JP5738112B2 - Coordinate input device, control method therefor, and program - Google Patents

Description

The present invention relates to a coordinate input device that calculates a pointing position with a pointing tool or a finger for a coordinate input effective area, a control method therefor, and a program.
The present invention relates to a coordinate input device capable of controlling a connected computer and writing characters, figures, and the like, for example, by detecting an indicated position indicated on an input screen by an indicator or a finger.

  A coordinate input device used to control a connected computer or to write characters, figures, etc. by instructing the coordinate input surface with an indicator (for example, a dedicated input pen, a finger, etc.) and inputting coordinates. Exists.

  Conventionally, various types of coordinate input devices (touch panels and digitizers) have been proposed or commercialized as this type of coordinate input device. For example, a touch panel that can easily operate a PC (personal computer) or the like by touching the screen with a finger without using a special instrument or the like is widely used.

  As a coordinate input method, there are various methods such as a method using a resistance film or a method using ultrasonic waves. Moreover, there exists patent document 1 as what used light, for example. In Patent Document 1, an optical system is known in which a retroreflective sheet is provided outside the coordinate input surface, the light from the light projecting unit is reflected by the retroreflective sheet, and the light quantity distribution is detected by the light receiving unit. In this optical method, the direction of a light shielding area shielded by a finger or the like in the coordinate input area is detected, and the light shielding position, that is, the coordinate of the coordinate input position is determined.

  Patent Document 2 discloses a technique for specifically detecting a pixel number corresponding to the direction of a light shielding region in the optical system. In the light intensity distribution, when multiple rising and falling parts that are candidates for the light shielding area are detected, the center point of the pixel data distribution obtained from the rising edge that is detected first and the falling edge that is detected last is the center. A configuration for detecting the pixel number is disclosed. This is a technique aiming at a countermeasure against the influence of the direct light reflection on the retroreflected light when the light from the light projecting unit is reflected on the indicator and detected by the light receiving unit.

  Furthermore, there exists patent document 3 as a technique with respect to the same subject. These techniques disclose the following techniques as solving means. This is a technique relating to a method for detecting a plurality of pixel numbers that cross at a predetermined threshold level with respect to rising and falling portions of a light amount fluctuation region corresponding to a light shielding region of a light amount distribution obtained from a light receiving unit generated when instructed.

U.S. Pat. No. 4,507,557 Japanese Patent No. 04125162 Japanese Patent Laying-Open No. 2005-056140

  The above-described conventional optical coordinate input device has the following problems.

  As described above, the invention related to the countermeasure against direct reflected light in the prior art includes, as described above, the center of two sets of falling and rising formed by the directly reflected light between the light shielding portions based on the falling rising at both ends. A technique for setting a pixel as a detection angle is disclosed. Conversely, a technique for detecting based on the falling and rising corresponding to the directly reflected light is also disclosed.

  However, it is necessary to distinguish the light amount distribution including directly reflected light from the case of two inputs (two or more inputs) using two pointing tools. The background art also discloses a technique for discriminating between direct reflected light and two inputs by correspondence with a pen signal, but there is a problem that it cannot be distinguished in the case of an instruction with a finger.

  The present invention has been made to solve the above problems. The object of the present invention is to receive direct reflected light from the light projecting part when the instruction is given near the sensor unit in the coordinate input effective area with a finger or pointing tool, and the light quantity distribution of the received light affects the light shielding. It is also possible to accurately detect the indicated position.

In order to achieve the above object, a coordinate input device according to the present invention comprises the following arrangement. That is,
The pointing position by the pointing tool or the finger with respect to the coordinate input effective area in which the recursive reflecting portion is provided in the peripheral portion and the plurality of sensor units are provided in the plurality of corner portions is projected by the light projecting portions of the plurality of sensor units. A coordinate input device for calculating from angle information corresponding to a light shielding portion by the pointing tool or a finger in a light amount distribution reflected recursively by the recursive reflecting portion and obtained by light receiving portions of the plurality of sensor units. ,
Directly reflected light from the indicator or finger based on light from the light projecting unit of one sensor unit affects the light shielding part of the indicator or finger in the light amount distribution obtained from the light receiving unit of the one sensor unit. A determination means for determining whether or not the direct reflected light influence range is instructed by the pointing tool or the finger based on angle information corresponding to a light shielding portion in a light receiving portion of a sensor unit other than the one sensor unit;
Calculating means for calculating one indicated position from the light shielding range affected by the direct reflected light when the determining means determines that the direct reflected light affected range is indicated by the pointing tool or finger.

  According to the present invention, when an instruction is given to the vicinity of the sensor unit in the coordinate input effective area with a finger or an indicator, the direct reflected light from the light projecting unit is received, and the light quantity distribution of the received light affects the light shielding. It is possible to accurately detect the indicated position.

It is a schematic block diagram of the coordinate input device of this invention. It is a disassembled perspective view of the sensor unit of the coordinate input device of this invention. It is an external view of the sensor unit of the coordinate input device of the present invention. It is explanatory drawing of the detection part of the sensor unit of the coordinate input device of this invention. It is a figure which shows the relationship between the pixel number N and angle (theta) of the coordinate input device of this invention. It is a block diagram which shows the structure of the control and arithmetic unit of the coordinate input device of this invention. It is a timing chart of light emission of the light projecting means of the coordinate input device of the present invention. It is a figure which shows an example of the light quantity distribution of the light detection means of the coordinate input device of this invention. It is a figure which shows an example of the time-dependent change of the reflective surface of the retroreflection means of the coordinate input device of this invention. It is explanatory drawing of the light quantity change of the coordinate input device of this invention. It is explanatory drawing of the light quantity change amount and light quantity change rate of the coordinate input device of this invention. It is explanatory drawing of the light-shielding part detection of the coordinate input device of this invention. It is explanatory drawing of the coordinate calculation of the coordinate input device of this invention. It is a flowchart which shows the coordinate calculation process of the coordinate input device of this invention. It is a flowchart which shows the detail of step S18155 of this invention. It is a figure which shows the example of instruction | indication operation of this invention, and the example of a detection of a sensor unit. It is a figure which shows the example of instruction | indication operation of this invention, and the example of a detection of a sensor unit. It is explanatory drawing of the direct reflected light with respect to the sensor unit of this invention. It is a figure which shows the example of instruction | indication operation of this invention, and the example of a detection of a sensor unit.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  First, a schematic configuration of the optical coordinate input device of the present invention will be described with reference to FIG.

  In FIG. 1, reference numerals 2001L and 2001R denote sensor units having a light projecting unit (light emitting unit) and a light receiving unit (detecting unit). In the present embodiment, the horizontal line indicates the X axis, the vertical line indicates the Y axis, and O indicates the intersection coordinates (0, 0) between the X axis and the Y axis. The sensor units 2001L and 2001R are arranged at a predetermined distance away from each other at a position parallel to the X axis and symmetrical to the Y axis of the coordinate input effective area 300 which is a coordinate input surface as shown in the drawing. In other words, the sensor units 2001L and 2001R are provided near both ends (corner portions) of one side of the coordinate input effective area 300.

  The sensor units 2001L and 2001R are connected to the control / arithmetic unit 20, receive a control signal from the control / arithmetic unit 20, and transmit the detected signal to the control / arithmetic unit 20. The control / arithmetic unit 20 and various processes in the coordinate input device are controlled. The coordinate input effective area 300 is an area in which this type of optical coordinate input device can detect the position instructed to input by an indicator (finger, input pen, etc.).

  Reference numeral 400 denotes a retroreflective unit having a retroreflective surface that recursively reflects incident light in the direction of arrival. The retroreflective unit 400 is disposed on the outer three sides (peripheral parts) of the coordinate input effective area 300, and the light projected from the left and right sensor units 2001L and 2001R in a range of approximately 90 ° to the sensor units 2001L and 2001R. Retroreflects towards.

  The light retroreflected by the retroreflecting unit 400 is one-dimensionally detected by the sensor units 2001L and 2001R, and a signal indicating the light amount distribution is transmitted to the control / arithmetic unit 20.

  With this configuration, when an input instruction is given to the coordinate input effective area 300 by the pointing tool, the light projected from the light projecting portions of the sensor units 2001L and 2001R is blocked by the pointing tool (light shielding portion). In this case, in the light receiving portions of the sensor units 2001L and 2001R, it becomes impossible to detect light (reflected light due to retroreflection) only at a portion (light-shielding portion) blocked by the indicator, and as a result, light from which direction Can be identified.

  Therefore, the control / arithmetic unit 20 detects the light-shielding portion of the portion instructed to be input by the pointing tool from the light amount change detected by the sensor units 2001L and 2001R. The direction (angle) of the light shielding position (designated position) is calculated from the information of the light shielding part. A method for detecting and calculating the light shielding portion will be described in detail later. Further, the light shielding position (coordinates) is geometrically calculated from the calculated direction (angle) and distance information between the sensor units 2001L and 2001R. At the same time, the coordinate value is output to an information processing apparatus such as a PC (personal computer) connected to a display unit (not shown) via a communication interface such as a USB.

  In addition, as a retroreflective member which comprises the retroreflective part 400, the bead type retroreflective sheet which has a retroreflective characteristic by arranging a spherical bead on a reflective surface is used. Alternatively, a retroreflective sheet or the like that causes a retroreflective phenomenon by regularly arranging corner cubes that are optical reflecting surfaces by machining or the like is used.

  Moreover, the material of the coordinate input surface which comprises the coordinate input effective area | region 300 of FIG. 1 is the display surface of the display apparatus combined with a coordinate input device, Furthermore, the transparent glass plate which is the front plate, or transparent Consists of resin plates. For example, the display device may be a liquid crystal display device, a plasma display device, a rear projection display device, or the like, or a configuration in which the coordinate input surface is a projector screen configuration. An integral configuration with this display device makes it possible to use as an interactive input device.

<Detailed description of sensor units 2001L and 2001R>
FIG. 2 is an exploded perspective view of the sensor units 2001L and 2001R, and shows a configuration example of a light projecting unit and a light receiving unit in the sensor units 2001L and 2001R.

  In FIG. 2, reference numeral 30 denotes a light projecting unit, and the light projecting unit 30 includes an infrared LED (light emitting diode) 31 that emits infrared light and a light projecting lens 32. The light emitted from the infrared LED 31 is projected by the light projecting lens 32 substantially parallel to the surface of the coordinate input effective area 300. At the same time, light is projected in a fan shape in the in-plane direction of the coordinate input effective area 300.

  3A is a front view of the assembled state of the sensor units 2001L and 2001R, and the arrows in FIG. 3 indicate that the light from the light projecting unit 30 is distributed in a fan shape in the in-plane direction of the coordinate input effective area 300. FIG. Is shown. FIG. 3B is a view of FIG. 3A viewed from the side. Similarly, the light is projected as a light beam restricted in the vertical direction substantially parallel to the surface of the coordinate input effective area 300, and is mainly displayed. FIG. 9 shows a state in which light is projected to the retroreflective portion 400.

  Referring back to FIG. 2 again, reference numeral 40 denotes a light receiving unit. The light receiving unit 40 includes a one-dimensional line CCD 41, a condensing lens 42 as a condensing optical system, a diaphragm 43 that roughly restricts the incident direction of incident light, The infrared filter 44 is configured to prevent the incidence of extra light such as visible light. Then, the light projected by the light projecting unit 30 is retroreflected by the retroreflecting unit 400, passes through the infrared filter 44 and the diaphragm 43, and is collected on the surface of the detection element group in the line CCD 41 by the condenser lens 42. Focused.

  In FIG. 2, 51 is a lower housing and 52 is an upper housing. The aperture 43, the upper housing 52, and the lower housing 51 mainly have a visual field in the height direction (the height direction from the surface of the coordinate input effective area 300) so that only the retroreflected light of the retroreflecting unit 400 passes. Is limiting. The field of view in the in-plane direction of the coordinate input effective area 300 is roughly limited.

  In the present embodiment, the lower housing 51 and the diaphragm 43 are integrally formed with each other, but it goes without saying that they may be formed of separate members.

  FIG. 4 is a diagram for explaining an optical path until light from the light projecting unit 30 of the sensor units 2001L and 2001R is retroreflected by the retroreflecting unit 400 and detected by the line CCD 41 as the light receiving unit. In the same figure, the same parts as those in FIGS. 2 and 3 are denoted by the same reference numerals.

  FIG. 4A is a front view seen from the direction perpendicular to the surface of the coordinate input effective area 300, and FIG. 4B is a side view thereof.

  In FIG. 4A, the light of the light projecting unit 30 projected in the substantially 90 ° direction described above is retroreflected through a light transmitting member (condensing lens 42, diaphragm 43, and infrared filter 44). 400 is retroreflected. Then, the light passes through the infrared filter 44 and the diaphragm 43 and enters the condenser lens 42. The light forms an image on the pixel 45 of the line CCD 41 in accordance with the incident angle with respect to the condenser lens 42 (FIG. 4 (b)). Accordingly, since the output signal of the line CCD 41 outputs a light amount distribution corresponding to the incident angle of the retroreflected light, the pixel number of the line CCD 41 indicates angle information.

  In the case of the present embodiment, the light projecting unit 30 and the light receiving unit 40 that is the detection unit are arranged so as to overlap each other. Therefore, the distance L (see FIG. 3B) is sufficiently smaller than the distance from the light projecting unit 30 to the retroreflective unit 400, and sufficient retroreflected light even when the distance L is present. Can be detected by the light receiving unit 40 which is a detection unit.

  FIG. 5 is a diagram showing the relationship between the pixel number N of the line CCD 41 observed by the light receiving optical system (light receiving unit 40) in the coordinate input device according to this embodiment and the angle θ to be derived. In the figure, the vertical axis indicates the angle θ to be derived, and the horizontal axis indicates the pixel number of the line CCD 41.

  Here, the normal direction of the line CCD 41 and the symmetry axes βL and βR of the light receiving optical system are made to coincide with each other, and the direction is defined as an angle of 0 °. At this time, if the measurement angle range is small, it is easy to design and manufacture a condensing lens 42 in which the relationship between the pixel number N of the line CCD 41 and the measurement angle θ is, for example, good linearity. However, when the measurement angle range becomes large, it becomes difficult to remove the optical distortion generated at the end of the condenser lens 42, and a large error occurs in the measurement angle.

  On the other hand, the coordinate input device according to the present embodiment displays the handwriting by the pointing tool on the display display by being arranged so as to overlap the display display (display device) or the front projector screen. This makes it possible to achieve ease of use like paper and pencil.

  Regarding the trend of display, the aspect ratio (aspect ratio) of the display area is mainly 4: 3, but the aspect ratio of 16: 9 is becoming widespread as seen in full HD images and the like. In other words, the coordinate input effective area 300 of the coordinate input device also has a horizontally long specification to cope with it.

<Description of Control / Calculation Unit 20>
Between the control / arithmetic unit 20 and the sensor units 2001L and 2001R, a CCD control signal for the line CCD 41, a clock signal for the CCD, an output signal of the line CCD 41, and a drive signal of the infrared LED 31 are exchanged.

  FIG. 6 is a block diagram showing a detailed configuration of the control / arithmetic unit 20.

  In the figure, 2001L and 2001R are sensor units, 81L and 81R are A / D converters, 82 is a memory, and 83 is a CPU (central processing unit) constituted by a one-chip microcomputer or the like. Further, 84L and 84R are LED drive circuits, 85 is an operation clock generation circuit for CPU control, 86 is an operation clock generation circuit (CLK) for CCD control, and 87 is a serial interface.

  In FIG. 6, the CCD control signal is output from the CPU 83 and performs shutter timing of the line CCD 41, data output control, and the like. The clock for the line CCD 41 is transmitted from the CLK 86 to the sensor units 2001L and 2001R, and is also input to the CPU 83 in order to perform various controls in synchronization with the line CCD 41.

  The LED drive signal is supplied from the CPU 83 to the infrared LEDs 31 in the sensor units 2001L and 2001R via the LED drive circuits 84L and 84R.

  Detection signals from the line CCD 41 which is a detection unit in the sensor units 2001L and 2001R are input to the A / D converters 81L and 81R in the control / arithmetic unit 20, and are converted into digital values under the control of the CPU 83. The converted digital value is stored in the memory 82 as necessary, and an angle calculation and further a coordinate value are calculated by a method described later, and the result is sent to the external terminal (personal computer) or the like via the serial interface 87 or the like. Is output via.

<Explanation of light intensity distribution detection>
FIG. 7 is a timing chart of control signals according to the present embodiment. In the figure, reference numerals 91, 92 and 93 are control signals for controlling the line CCD 41, and the shutter release time of the line CCD 41 is determined by the interval of the Sh signal 91. The ICGL signal 92 and the ICGR signal 93 are gate signals to the left and right sensor units 2001L and 2001R, respectively, and are signals for transferring the charge of the photoelectric conversion unit in the line CCD 41 to the reading unit.

  The LEDL signal 94 and the LEDR signal 95 are drive signals for the infrared LEDs 31 of the left and right sensor units 2001L and 2001R, respectively. Then, in order to light one infrared LED 31 (in this case, the infrared LED 31 in the sensor unit 2001L) in the first cycle of the Sh signal 91, the LEDL signal 94 is sent to the LED driving circuit (in this case, the LED driving circuit). 84L) and supplied to the infrared LED 31.

  In the next cycle, in order to turn on the other infrared LED 31 (in this case, the infrared LED 31 in the sensor unit 2001R), the LEDR signal 95 causes the other LED drive circuit (in this case, the LED drive circuit 84R) to be turned on. Then, it is supplied to the infrared LED 31.

  After the driving of both infrared LEDs 31 is completed, the signal of the line CCD 41 is read from the left and right sensor units 2001L and 2001R.

  For example, when there is no input by the pointing tool, that is, when there is no light-shielding portion, the read signal has a light amount distribution as shown in FIG. 8A as an output from each of the sensor units 2001L and 2001R. .

  FIG. 8 is a diagram showing the relationship between the output level (V) of the line CCD 41 and the CCD pixel number [N]. In the figure, the vertical axis represents the output level (V) of the line CCD 41, and the horizontal axis represents the CCD pixel number [N].

  Of course, such a light quantity distribution is not necessarily obtained in every system. That is, depending on the characteristics of the retroreflective part 400 (retroreflective characteristics depending on the incident angle of the retroreflective part 400), the characteristics of the light projecting part 30 including the LED 31, and the change with time (dirt of the reflection surface of the retroreflective part 400, etc.) This light quantity distribution changes. Furthermore, the relationship between the light quantity distribution and the configuration of the retroreflecting portion is as described above.

  In FIG. 8A, it is assumed that level A is the level when the maximum light amount is detected, and level B is the level when the minimum light amount is detected. Therefore, in the state where there is no reflected light, the obtained light quantity level is near level B, and the level of light quantity approaches the level A as the reflected light quantity increases. In this way, the detection signal output from the line CCD 41 is sequentially A / D converted by the corresponding A / D converters 81L and 81R, and then taken into the CPU 83 as digital data. The actual light amount distribution is based on factors such as the light projection distribution of the light projecting unit 30, the light reception distribution of the light receiving unit 40, the reflection characteristics of the retroreflective unit 400, and the distance from the sensor unit 2001L (2001R) to the retroreflective unit 400. The light intensity distribution is at the level specified. However, here, it is schematically shown in a uniform level state.

  FIG. 8B is a diagram illustrating an example of output when input is performed with the pointing tool, that is, when the reflected light of the retroreflecting unit 400 is blocked, and part C of FIG. Since the reflected light of the reflection part 400 is blocked, the light quantity of only that part is reduced.

  The detection of the light quantity distribution is performed by detecting the change in the light quantity distribution. Specifically, first, an initial state without input as shown in FIG. 8 (a) (hereinafter, data obtained in the initial state is referred to as initial data) is stored in the memory 82 in advance, and in each sample period. The difference between the obtained data and the initial data stored in the memory 82 is calculated. Then, based on the calculation result, it is determined whether or not there is a change as shown in FIG.

<Description of angle calculation>
In calculating the angle, first, it is necessary to detect a light shielding portion.

  As described above, since the light quantity distribution is not constant due to a change with time or the like, it is desirable to store the aforementioned initial data in the memory 82 at the time of starting the system. That is, when initial data is set at the time of shipment from a factory or the like and the data is not updated sequentially, for example, when dust adheres to the reflection surface of the retroreflective unit 400 at a predetermined position, retroreflection at that part is performed. Efficiency is reduced.

  Therefore, the saddle causes a serious result that the coordinate input operation is performed at the position (direction seen from the sensor units 2001L and 2001R), that is, erroneous detection is performed. Therefore, by storing initial data in the memory 82 at the time of starting the system or the like, even if the reflection surface of the retroreflective unit 400 is contaminated with dust or the like over time and the retroreflective efficiency is lowered, the state is set as the initial state. Since it can be set again, malfunctions can be eliminated.

  Of course, if the signal from the retroreflective unit 400 cannot be received at the part where the dust is attached, the coordinate cannot be detected, and the dust or the like must be removed by some method. However, if the optical signal from the retroreflecting unit 400 is greatly reduced, the signal reliability is reduced due to the S / N ratio (for example, although the same point is indicated). A phenomenon in which the coordinates fluctuate, and the coordinate calculation resolution is reduced).

  When the power is turned on, the output of the line CCD 41 is converted into an A / D converter 81L and 81R by the A / D converters 81L and 81R in a state where there is no input (no light-shielding portion) and light projection from the light projecting unit 30 is stopped. After D conversion, this value is stored in the memory 82 as Bas_data [N]. This value is data including variations in the bias of the line CCD 41, and is data in the vicinity of the level B in FIG. Here, [N] is the CCD pixel number of the line CCD 41, and a pixel number corresponding to an effective input range is used.

  Next, the light amount distribution in a state where light is projected from the light projecting unit 30 is stored. This is data represented by a solid line in FIG. 8A and is stored in the memory 82 as Ref_data [N]. This completes the storage of two types of data as initial data.

Then, using Bas_data [N] and Ref_data [N] stored in the memory 82, first, the presence / absence of an input by the pointing tool and the presence / absence of a light shielding portion are determined.

Here, the pixel data of the Nth pixel within the sample period of the output of the line CCD 41 is Norm_data [N].

  First, in order to specify a light-shielding portion, the presence or absence of input is determined based on the absolute amount of change in pixel data. This is to prevent erroneous determination due to noise or the like and to detect a certain amount of reliable change.

  Specifically, the absolute amount of change in pixel data is calculated by the following equation (1) for each pixel of the line CCD 41 and compared with a predetermined threshold value Vtha.

Norm_data_a [N] = Norm_data [N]-Ref_data [N] (1)
Here, Norm_data_a [N] corresponds to the absolute change amount in each pixel of the line CCD 41.

  Since this process only calculates the absolute change amount Norm_data_a [N] of each pixel of the line CCD 41 and compares it with the threshold value Vtha, the processing time can be shortened and the presence / absence of input can be determined at high speed. It is. Then, when the number of pixels exceeding the threshold value Vtha for the first time is detected exceeding a predetermined number, it is determined that there is an input from the pointing tool.

  Next, a method for determining the input point by calculating the change ratio of the pixel data in order to detect with higher accuracy will be described.

  FIG. 9 is a diagram illustrating a retroreflective surface of the retroreflective unit 400. In the figure, reference numeral 910 denotes a reflecting surface of the retroreflecting unit 400, and 911 denotes an indicator. Here, assuming that the reflectance of the region 10 on the reflecting surface 910 has decreased due to dirt or the like, the pixel data distribution (light amount distribution) of Ref_data [N] at this time is the region 10 as shown in FIG. The amount of reflected light at the portion corresponding to is reduced.

  FIG. 10 is a diagram showing the relationship between the output level (V) of the line CCD 41 and the CCD pixel number [N]. In the figure, the vertical axis represents the output level (V) of the line CCD 41, and the horizontal axis represents the CCD pixel number [N].

  In the state of FIG. 10 (a), assuming that approximately half of the retroreflective portion 400 is covered with the pointing tool 911 as shown in FIG. 9, the amount of reflected light is approximately halved, which is indicated by the bold line in FIG. 10 (b). The distribution Norm_data [N] will be observed. When the above formula (1) is applied to this state, the pixel data distribution is as shown in FIG.

  FIG. 11A is a diagram illustrating the relationship between Norm_data_a [N] and the CCD pixel number [N]. In the figure, the vertical axis indicates Norm_data_a [N], and the horizontal axis indicates the CCD pixel number [N].

  FIG. 11B is a diagram illustrating the relationship between Norm_data_r [N] and the CCD pixel number [N]. In the figure, the vertical axis indicates Norm_data_r [N], and the horizontal axis indicates the CCD pixel number [N].

  Here, in FIG. 11, the vertical axis represents the differential voltage from the initial state.

  When this pixel data is compared with the threshold value Vtha, there is a case where the original input range is deviated (broken line area in FIG. 11A). Of course, by setting the threshold value Vtha to a smaller value, a certain degree of detection is possible, but the possibility of being affected by noise or the like increases, resulting in an adverse effect of deteriorating coordinate calculation performance.

  Therefore, the amount of light of the light shielding portion blocked by the indicator 911 is the first half of both the area 10 and the area 11 of the reflecting surface 910 (equivalent to the V1 level in the area 10 and equivalent to the level V2 in the area 11). The ratio of change can be calculated in 2).

Norm_data_r [N] = Norm_data_a [N] / (Bas_data [N] -Ref_data [N]) (2)
The calculation result of the equation (2) is as shown in FIG. 11B, and the light quantity distribution is represented by a change ratio. Therefore, even when the reflectivity of the retroreflecting unit 400 is different, it can be handled equally.

  A threshold value Vthr is separately set for this pixel data (light quantity distribution). Then, from the pixel number of the rising part and the falling part of the light quantity variation region corresponding to the light shielding part in the light quantity distribution corresponding to the point crossing the threshold value Vthr, for example, the pixel corresponding to the input by the pointing tool at the center of both By doing so, pixel information can be acquired with high accuracy. However, if there is an influence of the direct reflected light of the pointing tool 911 itself, a plurality of light shielding portions are generated, and an error occurs if the coordinate values are calculated from the pixel numbers of the simple rising and falling portions. The processing for the directly reflected light will be described later.

  By the way, FIG. 11B is schematically drawn for convenience of explanation, and an actual detection signal waveform is displayed in detail as shown in FIG.

  Now, it is assumed that the rising portion of the light-shielding region as compared with the threshold value Vthr exceeds the threshold value Vthr at the Nrth pixel, and is below the threshold value Vthr at the Nfth pixel. At this time, as described above, the pixel number Np of the line CCD 41 to be output may be calculated as the median value of the pixel numbers of the rising part and the falling part as shown in the following formula (3). The pixel interval of the line CCD 41 becomes the resolution of the output pixel number.

Np = Nr + (Nf-Nr) / 2 (3)
Therefore, in order to detect with higher resolution, a virtual pixel number crossing the threshold value Vthr is calculated using the data level of each pixel and the data level of the immediately preceding adjacent pixel.

In FIG. 12, the output level of the line CCD 41 with the pixel number Nr is Lr, and the output level of the pixel number Nr-1 is Lr-1. Similarly, the output level of the pixel number Nf is Lf, and the output level of the pixel number Nf-1 is Lf-1. At this time, if the pixel numbers to be detected are the respective virtual pixel numbers Nrv and Nfv,
Nrv = Nr-1 + (Vthr-Lr-1) / (Lr-Lr-1) (4)
Nfv = Nf-1 + (Vthr-Lf-1) / (Lf-Lf-1) (5)
Can be calculated. According to this calculation formula, a virtual pixel number corresponding to the output level, that is, a pixel number smaller than the pixel number of the line CCD 41 can be acquired. And the virtual center pixel Npv of these virtual pixel numbers Nrv and Nfv is determined by the following equation (6).

Npv = Nrv + (Nfv-Nrv) / 2 (6)
Thus, by calculating the virtual virtual pixel number that crosses the threshold value Vthr of the predetermined level from the pixel number of the pixel of the data level exceeding the threshold value Vthr, the adjacent pixel number, and the data level thereof, the resolution can be further increased. High detection can be realized.

<Conversion from CCD pixel number to angle information>
Next, in order to calculate the actual coordinate value of the pointing tool from the center pixel number corresponding to the virtual center pixel indicating the center point of the light shielding portion, it is necessary to convert this center pixel number into angle information.

FIG. 5 is a graph plotting the relationship between the obtained pixel number and the angle θ. When an approximate expression of this relationship (the following expression (7)) is defined,
θ = f (N) (7)
Thus, it is possible to convert the pixel number to θ using this approximate expression (conversion expression).

  In the present embodiment, the lens group of the light receiving unit 40 of the sensor units 2001L and 2001R described above is configured so that it can be approximated using a primary approximation formula. However, there are cases where it is possible to obtain angle information with higher accuracy by using a higher-order approximate expression due to optical aberrations of the lens and the like.

  Here, what lens group is adopted is closely related to the manufacturing cost. In particular, when correcting optical distortion generally generated by lowering the manufacturing cost of the lens group using a higher-order approximate expression, a certain amount of calculation capability (calculation speed) is required. Therefore, both may be set as appropriate in consideration of the coordinate calculation accuracy required for the target product.

  As shown in FIG. 9, the light shielding state when instructed by the pointing tool 911 is shown in FIG. 11, but actually, a more complicated light shielding region is formed by the direct reflected light of the pointing tool 911 itself. Measures against this are the main points of the present invention and will be described in detail later.

<Description of coordinate calculation method>
FIG. 13 is a diagram illustrating a positional relationship between the sensor unit 2001L and the sensor unit 2001R in the coordinate input device according to the present embodiment. It is assumed that the coordinate input effective area 300 is arranged with the X axis in the horizontal direction, the Y axis in the vertical direction, and the center of the coordinate input effective area 300 at the origin position. Then, the sensor unit 2001L and the sensor unit 2001R are attached symmetrically with respect to the Y axis on the left and right sides of the upper side of the coordinate input effective area 300, and the distance between the sensor units 2001L and 2001R is Ds.

  Further, as shown in the drawing, the light receiving surfaces of the line CCDs 41 of the sensor units 2001L and 2001R are arranged such that the normal direction forms an angle of 45 ° with the X axis, and the normal direction is 0 ° (reference Direction). At this time, the sign of the angle is the clockwise direction in the case of the sensor unit 2001L arranged on the left side, and the counterclockwise direction in the case of the sensor unit 2001R arranged on the right side. The direction of is defined as the “+” direction.

  Furthermore, Po in the figure is the position of the intersection of the sensor units 2001L and 2001R in the normal direction, and the distance from the origin in the Y-axis direction is defined as Poy. At this time, if the angles obtained by the sensor units 2001L and 2001R are θL and θR, the coordinates P (x, y) of the point P to be detected are obtained by the following equations (8) and (9).

x = Ds / 2 * (tanθR-tanθL) / (1-(tanθR * tanθL)) (8)
y = Ds / 2 * (tanθR + tanθL + (2 * tanθR * tanθL)) /
(1-(tanθR * tanθL)) + P0y (9)
Next, coordinate calculation processing of the coordinate input device according to the present embodiment will be described with reference to FIG.

  FIG. 14 is a flowchart showing coordinate calculation processing from data acquisition to coordinate calculation of the coordinate input device according to the present embodiment.

  When the power is turned on, first, in step S1801, various initializations relating to the coordinate input device such as port setting and timer setting of the CPU 83 are performed. Next, in step S1802, a CCD pixel effective range of the line CCD 41, which is a light receiving element to be described later, is set by reading from a setting value stored in advance in the memory 82, for example. Next, in step S1803, the initial reading count of the initial reading operation of the line CCD 41 is set.

  This initial reading operation is an operation for removing unnecessary charges from the line CCD 41 when the coordinate input device is activated. In the line CCD 41, unnecessary charges may be accumulated when the line CCD 41 is not operated. If the coordinate input operation is executed in a state where the charges are accumulated, detection becomes impossible or erroneous detection is caused. . Therefore, in order to avoid this, in step S1804, a predetermined number of reading operations are executed in a state where the light projection by the light projecting unit 30 is stopped. Thereby, unnecessary charges are removed.

  In step S1805, it is determined whether the number of readings has reached a predetermined number. If the number of readings has not reached the predetermined number (NO in step S1805), the process returns to step S1804. On the other hand, if the number of readings has reached the predetermined number (YES in step S1805), the process proceeds to step S1806.

  In step S1806, pixel data (Bas_data [N]) of the line CCD 41 in a state where the light projection by the light projecting unit 30 is stopped is taken as base data. In step S 1807, the base data is stored in the memory 82.

  In step S1808, pixel data (corresponding to an initial light amount distribution: Ref_data [N]) of the line CCD 41 in a state where light is emitted from the light projecting unit 30 is fetched as reference data. In step S 1809, the reference data is stored in the memory 82.

  The processing so far is the initial setting operation when the power is turned on. It goes without saying that this initial setting operation may be configured to operate according to the operator's intention using a reset switch or the like configured in the coordinate input device. After this initial setting operation, a transition is made to a normal take-in operation state for inputting coordinates with the pointing tool.

  In the normal capture operation, first, in step S1810, the normal capture operation of the line CCD 41 is executed in the coordinate input sampling state to capture pixel data (Norm_data [N]). Next, in step S1811, a difference value between the memory data (reference data Ref_data [N]) and the pixel data (Norm_data [N]) is calculated. In step S1812, the presence / absence of a light-shielding portion, that is, whether or not there is a coordinate input, is determined based on the difference value and the above-described threshold value Vthr. If it is determined that there is no coordinate input (NO in step S1812), the process returns to step S1810.

  On the other hand, if it is determined that there is a coordinate input (YES in step S1812), the process proceeds to step S1813, and the ratio of change in pixel data is calculated using equation (2). Next, in step S1814, the falling and rising of the pixel data distribution corresponding to the light-shielding portion by the pointing tool are detected using the threshold Vthr with respect to the calculated change ratio of the pixel data. Then, using the detected falling and rising edges and the equations (4), (6), and (7), a virtual center pixel number that is the center of the light shielding portion is calculated.

  In step S1815, for example, Tanθ is calculated from the calculated center pixel number using an approximate expression (Expression (7)).

  Subsequent to the above basic processing, in the present embodiment, the processing of step S18155 (direct reflected light countermeasure processing) is further executed here in order to cope with the influence of the direct reflected light of the pointing tool. Details of this process will be described later.

  In step S1816, the input coordinate P (x, y) of the pointing tool is calculated using Tan θ calculated for the sensor units 2001L and 2001R and the equations (8) and (9).

  In step S1817, the calculated coordinate value is transmitted to the external terminal. This transmission may be performed using an arbitrary communication interface such as serial communication such as USB or RS232C. Then, after the transmission process in step S1817 is completed, the process returns to the process in step S1810, and thereafter, this process is repeated until the power is turned off or a reset state is set according to the operator's intention.

  If this repetition cycle is set to about 10 [msec], the coordinate input device according to the present embodiment can output the coordinates designated by the pointing tool 911 to the external terminal at a cycle of 100 times / second.

  As described above, according to the coordinate input device according to the present embodiment, the difference between the maximum light amount and the minimum light amount of the detection signal waveform can be reduced, so that the coordinate calculation resolution of the coordinate input device is significantly improved. be able to.

<Explanation on direct reflected light countermeasure processing>
Here, a detailed description of the direct reflected light processing in step S18155 of FIG. 14, which is the main focus of the present invention, will be given with reference to FIG. Here, as a premise, the instruction with the pointing tool (finger, pen, etc.) is only a maximum of two points, and the coordinate input effective area is an example of processing related to an instruction (input) pattern having a high frequency with no extreme bias. Will be described.

  However, by using a configuration similar to that of the present invention, it is also possible to deal with inputs of three or more points. In the description, FIGS. 16 to 19 schematically show the designated positions assumed in the cases of the designated patterns and the light quantity distributions in the left and right sensor units 2001L and 2001R.

  As described above, after calculating the angle (Tan θ) in step S1815 in FIG. 14, the direct reflected light countermeasure process is executed in step S18155. As shown in FIG. 15, step S18155 of the direct reflected light countermeasure process includes a group of steps from step 181551 to step S181555.

  First, in step S181551, it is determined whether at least one of the left and right sensor units 2001L and 2001R has two sets of rising and falling higher than a predetermined threshold in the light shielding portion in the received light amount distribution. To do. Specifically, in step S1814, when the rising portion and the falling portion are determined with a predetermined threshold (Vthr), the number of rising and falling edges is stored in the memory 82, and the stored number is calculated. Use to determine.

  First, in step S181551, a process when there are not two sets of rising and falling exceeding a predetermined threshold (NO in step S18155) will be described. FIG. 16A shows the positional relationship between the sensor units 2001L and 2001R when only one point is designated at the designated position 90 on the coordinate input effective area 300. 112L is an angle on the narrow angle side formed by a line formed by the indicated position 90 from the sensor unit 2001L with respect to a reference line 1000 connecting the positions (reference positions) where the sensor unit 2001L and the sensor unit 2001R are arranged. . An angle corresponding to the same sensor unit 2001R is 112R.

  Further, the direct reflected light reference angle 111L is formed by a reference line 1000 and a line segment connecting the boundary of the direct reflected light influence range 101R and the sensor unit 2001L, which is affected by the direct reflected light according to the instruction of the pointing tool in the sensor unit 2001R. Is an angle. The directly reflected light reference angle corresponding to the same sensor unit 2001R is 111R. The direct reflected light reference angles 111L and 111R will be described later in association with the influence of the directly reflected light.

  FIG. 16A shows a case where an instruction is given to a position where the angle 112L is larger than the direct reflected light reference angle 111L and the angle 112R is larger than the direct reflected light reference angle 111R. FIGS. 16B and 16C are light amount distributions in the sensor units 2001L and 2001R, respectively. As will be described in detail later, of course, the fact that the angles 112L and 112R are larger than the directly reflected light reference angles 111L and 111R for both sensor units means that there is no influence of the directly reflected light. Therefore, when pointing to the pointing position 90 with the pointing tool, as can be seen from FIGS. 16B and 16C, the number of light shielding portions is only one.

  When the number of light shielding portions detected by the sensor units 2001L and 2001R is only one, in step S181551, the following determination is always made. That is, it is determined that at least one of the sensor units 2001L and 2001R does not have two sets of rising and falling portions that are equal to or greater than the predetermined threshold in the light shielding portion (NO in step S18155). That is, when there is one light-shielding part detected by both sensor units, it can be determined that only one point of instruction by the pointing tool has been instructed in an area not directly affected by reflected light. In this case, in step S181555, similarly to the process when the instruction by the pointing tool is one point (normally one input process), a process for calculating the angle from the pixel number corresponding to the designated position is performed as the processing method. . Specifically, since Tan θ is calculated as angle information in step S1815, the angle information is retained as it is and used for coordinate calculation in the next step S1816.

  Next, processing in the case where there are two sets of rising and falling that are equal to or greater than the predetermined threshold in step S181551 (YES in step S18155) will be described. In this case, the following two cases can be considered. As a combination of the number of light shielding portions, one of the sensor units 2001L and 2001R is 1, and the other is 2, and both are 2.

  First, the case where the number of light shielding parts detected by the sensor unit 2001L is 2 and the number of light shielding parts detected by the sensor unit 2001R is 1 in the former case will be described. Since the reverse case is the same, it is omitted here. In this case, two more cases can be considered. FIG. 17A schematically shows the designated position in case 1 and FIG. 17B schematically shows the designated position in case 2. FIG. 17C shows the light amount distribution in the sensor unit 2001L in case 1 of FIG. 17A, and FIG. 17D shows the light amount distribution in the sensor unit 2001R. Similarly, FIG. 17E shows the light amount distribution in the sensor unit 2001L in case 2 of FIG. 17B, and FIG. 17F shows the light amount distribution in the sensor unit 2001R.

  In case 1, as shown in FIG. 17A, the coordinate input effective area 300 is designated at two points of designated positions 90 and 91. The relationship between the two designated positions 90 and 91 is arranged along a straight line from the sensor unit 2001R. Further, an input instruction is made outside the direct reflected light influence range 101L for the sensor unit 2001L and the direct reflected light influence range 101R for the sensor unit 2001R.

  Therefore, in this case, in the light amount distribution (FIG. 17C) in the sensor unit 2001L, two sets of rising and falling of the light shielding portion are detected. On the other hand, in the light amount distribution in the sensor unit 2001R (FIG. 17D), the two pointed positions 90 and 91 are exactly the same angle from the sensor unit 2001R, so that the light-shielding part rises and falls only in one set. Is detected. This is, of course, a normal case assumed even in conventional coordinate input, which has nothing to do with direct reflected light.

  Next, the case 2 will be described. The pointing position 90 by the pointing tool is only one place in the direct reflected light influence range 101L with respect to the sensor unit 2001L. In this case, as for the light quantity distribution in the sensor unit 2001R far from the designated position 90, as shown in FIG. However, in the light quantity distribution in the sensor unit 2001L close to the indicated position 90 within the direct reflected light influence range 101L with respect to the sensor unit 2001L, as shown in FIG. Is done. This is due to directly reflected light, and this will be described with reference to FIG.

  FIG. 18 is an enlarged view of the vicinity of the sensor unit 2001L in FIG. As shown in FIG. 18A, when an area near the sensor unit 2001L is indicated, the light from the light projecting unit 30 is blocked by the indicating tool before reaching the retroreflecting unit 400. The configuration of detecting the indicated position by detecting the light shielding state is the principle of the original optical coordinate input device. However, all the light blocked here must be absorbed by the indicator. , Some reflected light is generated. The way of reflection varies greatly depending on the state and angle of the reflecting surface of the pointing device, but generally becomes scattered light. When it becomes scattered light, the amount of reflected light itself is usually not so large.

  However, as shown in FIG. 18A, when the pointing position 90 of the pointing tool is in the vicinity of the light projecting unit 30, the direct reflected light 103L (more precisely, the reflected light is the return arrow) has a short optical path distance, Since the attenuation is small, the amount of light is detected by the light receiving unit 40 of the sensor unit 2001L. In addition, in the pointing device, if there is a vertical surface that is substantially perpendicular to the coordinate input surface and smooth with respect to the direction of the light beam from the sensor unit 2001L, the surface becomes a regular reflection surface. Then, the light from the light projecting unit 30 is specularly reflected on its surface like the direct reflected light 103L, returns in the direction substantially opposite to the projection direction, and is detected by the light receiving unit 40 when the mirror image-related conditions are just met. End up.

  In that case, stronger reflected light (103L) is received by the sensor unit 2001L than in the case of scattered light. For both the scattered light and the specularly reflected light, there is no strict division, and even in the case of scattered light, a specularly reflected light surface exists when viewed microscopically. That is, there is only a difference between the two, and it can be regarded as the same directly reflected light optically. Hereinafter, the scattered light and the regular reflection are not particularly distinguished, and are directly reflected light. In any case, as the distance between the indication position and the sensor unit increases, the amount of received direct reflected light decreases, and it is possible to provide a reference value.

  As shown in FIG. 18A, assuming that the pointing tool has a substantially cylindrical shape, the direct reflected light 103L from the center position of the reflecting surface at the substantially pointing position 90 is reflected from the sensor unit 2001L. It becomes the maximum because it becomes a plane perpendicular to the light ray direction of the projected light. In this case, as shown in FIG. 18C, a light peak is generated in the pixel range 105 inside the original light-shielding portion 104 in the light amount distribution in the light reception by the sensor unit 2001L.

  Therefore, looking only at the light amount distribution in FIG. 18C, it is indistinguishable from the state where there are two light shieldings as a result of instructing two places. As described above, in step S1812, the presence / absence of a light-shielding portion is determined using a predetermined threshold value. Therefore, when the directly reflected light 103L larger than the predetermined threshold is detected, the number of light shielding portions corresponding to the number of input instructions should be 1 in step S1812, but it is different from the actual due to the influence of the directly reflected light 103L. The number of light shielding parts is counted as 2. In this case, an error occurs if the pixel number is calculated based on the two rising and falling edges where the number of light shielding portions is 2, and the angle information is calculated and the coordinate position is calculated based on the angle information.

  On the other hand, as shown in FIG. 18B, when the pointing position by the pointing tool is far from the sensor unit 2001L, the amount of light is small even if the direct reflected light 103L from the light projecting unit 30 enters the light receiving unit 40. Become. Since the round-trip optical path to the reflecting surface becomes longer, as shown in FIG. 18 (d), it falls below the predetermined threshold value in step S1812, and therefore the number of light-shielding portions is counted as 1 and is not affected by malfunction.

  As described above, the direct reflected light influence range 101L according to the instruction is uniquely determined by physical conditions and electrical conditions. The physical conditions include the surface state and shape of an indicator (finger, pen, etc.) used for coordinate input, the angle with respect to the coordinate input surface, and the light projection amount of the light projecting unit 30. The electrical condition is a predetermined threshold used in step S1812 in the light receiving unit 40. Therefore, the directly reflected light influence range 101L by the instruction is a semicircular range corresponding to the distance from the sensor unit 2001L in which the directly reflected light is just a predetermined threshold.

  As described above, the boundary of the influence range of the directly reflected light influence range 101L that is uniquely determined by various conditions is indicated by 102L in FIG. 18B. On the other hand, the direct reflected light reference angle 111R is an angle formed by a reference line 1000 and a line segment connecting the boundary 102L and the sensor unit 2001R. The same applies to the direct reflected light reference angle 111L corresponding to the sensor unit 2001L.

  Here, the description returns to the case 2 of FIG. When an instruction is given to one point in the direct reflected light influence range 101L, an error occurs as if two points were input as in case 1 due to the influence of the direct reflected light by the instruction as shown in FIG. It will be detected.

  Therefore, in the present invention, if there are two sets of rising and falling edges that are equal to or greater than the predetermined threshold value in the light shielding portion in step S181551 in FIG. 15 (YES in step S181551), the following processing is performed.

  First, in step S181552, it is determined whether the angles 112L and 112R from the sensor unit at the input instruction position are within a predetermined angle range (direct reflected light reference angles 111L and 111R) or outside the range. Here, the angle 112L is an angle formed by a line formed by the pointing position 90 of the pointing tool from the sensor unit 2001L with respect to a reference line 1000 connecting the positions where the sensor unit 2001L and the sensor unit 2001R are arranged. This is as described in FIG.

  As described above, the direct reflected light reference angles 111L and 111R serving as the determination reference are the following angles. That is, the maximum is within the angle formed by the reference line 1000 and the line segment connecting the boundaries 102R, 102L of the direct reflected light influence ranges 101R, L according to the instructions of the pointing tool in the sensor units 2001R, 2001L and the sensor units 2001L, 2001R. Is an angle. Instead of the influence of the direct reflected light of the sensor unit itself, the influence of the direct reflected light of the other sensor unit is determined by the angle from the sensor unit.

  In the case 1 of FIG. 17A, in step S181552, since there is only one light-shielding portion in the light amount distribution (FIG. 17D) regarding the sensor unit 2001R, in step S181552 regarding the other sensor unit 2001L. No judgment is made. In the light amount distribution (FIG. 17C) regarding the sensor unit 2001L, since there are two light-shielding portions, the determination regarding the other sensor unit 2001R is performed. With respect to the sensor unit 2001R, the angle 112L with respect to the light shielding portion is larger than a predetermined angle (angle 111L) as a reference for determination, so the light shielding portion in FIG. 17C is not directly reflected light, but is based on original two-point input. It can be determined that it is a thing. Therefore, in that case (NO in step S181552), as shown in FIG. 15, in step S181554, as in the conventional case, as a processing method, two sets of rising and falling are calculated as two different designated positions, respectively. Process. Specifically, since Tan θ is already calculated as two angle information in step S1815, the angle information is held as it is, and the coordinate calculation (coordinate calculation of two designated positions) in the next step S1816 is performed. Use to do.

  In the case 2 of FIG. 17B, in step S181552, since there is only one light-shielding portion in the light amount distribution (FIG. 17F) regarding the sensor unit 2001R, the processing of step S181552 regarding the other sensor unit 2001L is performed. No judgment is made. In the light amount distribution relating to the sensor unit 2001L (FIG. 17E), since there are two light shielding portions, the determination in step S181552 relating to the other sensor unit 2001R is performed. With respect to the sensor unit 2001R, the angle 112L with respect to the light shielding portion is smaller than a predetermined angle (angle 111L) that serves as a reference for determination. For this reason, step S181553, which is a process for the two light-shielding portions when receiving the influence of the directly reflected light related to the other sensor unit 2001L, is executed.

  Regarding the processing for the two light-shielding portions (step S181553), the technique disclosed in Patent Document 2 is used as a processing method. Specifically, when a plurality of rising portions and falling portions that are light shielding portion candidates are detected, the following processing is performed. That is, the center point of the pixel data distribution (pixel distribution) obtained from the first detected rising portion (smallest pixel number) and the last detected falling portion (largest pixel number) is detected as the central pixel number. . Regarding the processing for the two light shielding states in FIG. 17 (e), since it is found in step S181552 that the light shielding state is directly reflected light at this stage, this processing is limited to the method of this Patent Document 2. Is not to be done. Any technique may be used as long as it detects the center pixel number for one instruction from the light-shielded state in FIG.

  Next, as a combination of the number of light-shielding portions, a case where the number of sensor units among the sensor units 2001L and 2001R is 2 will be described with reference to FIG.

  In either case 1 of FIG. 19 (a) or case 2 of FIG. 19 (b), in step S181552, in the light quantity distribution (FIG. 17 (c) to (f)) regarding the sensor unit 2001L and the sensor unit R, Two light-shielding portions are detected. Accordingly, the determination in step S181552 regarding both sensor units 2001L and 2001R is performed.

  In the case 1, the determination of step S181552 is performed with respect to the angle 112L with respect to the light shielding portion with respect to the presence or absence of the direct reflection light of the sensor unit 2001R, and with respect to the angle 112R with respect to the light shielding portion with respect to the presence or absence of the direct reflection light of the sensor unit 2001L. Do. In any case, since it is determined that the angle is larger than the predetermined angles (angles 111L and 111R) which are the criteria for determination here, the light-shielding portions in FIGS. 19C and 19D are directly reflected light. Instead, it is determined that the original two-point input is used. Therefore, in that case (NO in step S18552), as shown in FIG. 15, in step S181554, two sets of rising and falling edges are calculated as separate two designated positions, as in the conventional case. Specifically, since Tan θ is already calculated as two angle information in step S1815, the angle information is held as it is, and the coordinate calculation (coordinate calculation of two designated positions) in the next step S1816 is performed. Use to do.

  Also in case 2, the determination in step S181552 is performed with respect to the angle 112L with respect to the light shielding portion with respect to the presence or absence of the direct reflection light of the sensor unit 2001R and with respect to the angle 112R with respect to the light shielding portion with respect to the presence or absence of the direct reflection light with respect to the sensor unit 2001L. Do. Regarding the presence or absence of the direct reflected light of the sensor unit 2001R, it is determined that the angle 112L with respect to the light shielding portion detected by the sensor unit 2001L is larger than the predetermined angle (angle 111L) that serves as a determination reference. Accordingly, it can be determined that the light-shielding portion in FIG. 19F is not due to the direct reflected light but is due to the original two-point input.

  On the other hand, regarding the presence / absence of the directly reflected light of the sensor unit 2001L, it is determined that the angle 112R with respect to the light shielding portion detected by the sensor unit 2001R is smaller than the predetermined angle (angle 111R) that serves as a determination reference. Therefore, it can be determined that the light-shielding portion in FIG. 19 (e) is due to directly reflected light. That is, in this case, two input positions are along a straight line from the sensor unit 2001L, and one of the input positions is within the direct reflected light influence range 101L in the vicinity of the sensor unit 2001L.

  In this case, with respect to the sensor unit 2001R, in step S181554, as in the conventional case, two sets of rising and falling portions are calculated as two different designated positions. On the other hand, as for the sensor unit 2001L, the technique shown in Patent Document 2 is used as in the case of the sensor unit 2001L of case 2 in FIG. Specifically, when a plurality of rising portions and falling portions that are candidate light shielding portions are detected, the center point of the pixel data distribution obtained from the first detected rising portion and the last detected falling portion is the center. Detect as pixel number.

  As described above, based on the number of sets of rising and falling portions and the determination result of whether or not the angle from the sensor unit at the input instruction position is within a predetermined angle (direct reflected light reference angle) range. Then, the processing method for calculating the angle of the designated position with respect to the coordinate input effective area is selected. Thereby, even when there is an influence of direct reflected light, accurate coordinates can be calculated without erroneous detection.

  In the cases described above, most cases that occur in normal operations can be dealt with. However, for example, cases other than the above may occur. For example, in the case of two inputs, there are a case where one point is input in each of the directly reflected light affected ranges 101R and 101L, or a case where two points are simultaneously input to either of the directly reflected light affected ranges 101R and 101L. In this case as well, although detailed explanation is omitted here, it can be dealt with by executing processing corresponding thereto.

  In the former case, the sensor units 2001L and 2001R detect three light-shielding portions, but after making a determination on a predetermined angle (direct reflected light determination reference angle) that is a reference for determining directly reflected light from each other. Perform the following process. Only the light-shielding portion with the smallest angle uses the technique shown in Patent Document 2 for conventional processing and the remaining two large angles.

  On the other hand, in the latter case, one of the sensor units detects four light-shielding portions and the other sensor unit detects one or two light-shielding portions. The following processing is performed. In the determination regarding the direct reflected light reference angle, the technique shown in Patent Document 2 is used for the four light shielding portions on the side of the sensor unit in which it is determined that the light shielding portion is caused by the direct reflected light. Then, the same processing as in the conventional case is performed.

  Note that the above processing is not limited to this, and any processing may be used as long as the processing regarding the direct reflected light reference angle is added.

  Moreover, in the above description, the structure which detects a coordinate is demonstrated based on two sensor units. However, the invention relating to the direct reflected light countermeasure processing of the present invention is not limited to this configuration, and it goes without saying that it can be applied to a case where three or more sensor units are rearranged at any time during coordinate calculation.

  As described above, according to the present embodiment, when an instruction is given in the vicinity of the sensor unit in the coordinate input effective area with a finger or an indicator, the light directly reflected from the light projecting unit is received, and the received light quantity distribution. Even in the case where the light shielding is affected, the designated position can be accurately detected.

  Specifically, although there is actually one light-shielding portion by one point input by the pointing tool, a portion with a large amount of light is formed between the light-shielding light quantity distributions by the direct reflected light from the pointing tool, and apparently The case where it is difficult to distinguish from two-point input can be distinguished, and accurate detection is possible. That is, for a one-point input that is directly affected by reflected light, it is possible to accurately detect the position of the one-point input, and in the case of two inputs, it is possible to accurately detect the position of two points.

  The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed.

Claims (7)

The pointing position by the pointing tool or the finger with respect to the coordinate input effective area in which the recursive reflecting portion is provided in the peripheral portion and the plurality of sensor units are provided in the plurality of corner portions is projected by the light projecting portions of the plurality of sensor units. A coordinate input device for calculating from angle information corresponding to a light shielding portion by the pointing tool or a finger in a light amount distribution reflected recursively by the recursive reflecting portion and obtained by light receiving portions of the plurality of sensor units. ,
Directly reflected light from the indicator or finger based on light from the light projecting unit of one sensor unit affects the light shielding part of the indicator or finger in the light amount distribution obtained from the light receiving unit of the one sensor unit. A determination means for determining whether or not the direct reflected light influence range is instructed by the pointing tool or the finger based on angle information corresponding to a light shielding portion in a light receiving portion of a sensor unit other than the one sensor unit;
Calculating means for calculating one indicated position from the light shielding range affected by the direct reflected light when the determining means determines that the direct reflected light affected range is designated by the pointing tool or finger. Coordinate input device characterized by When there are two light shielding portions in the light receiving portion of the one sensor unit, and the angle information corresponding to the light shielding portions in the light receiving portions of sensor units other than the one sensor unit corresponds to the direct reflected light influence range, The coordinate input device according to claim 1, wherein the determination unit determines that the direct reflected light influence range of the one sensor unit is instructed by the pointing tool or a finger. When there are two light-shielding portions in the light-receiving portion of the one sensor unit, and angle information corresponding to the light-shielding portions in the light-receiving portions of sensor units other than the one sensor unit does not correspond to the direct reflected light influence range, The coordinate input device according to claim 1, wherein the determination unit determines that the outside of the direct reflected light influence range of the one sensor unit is instructed by the pointing tool or a finger. The pointing position by the pointing tool or the finger with respect to the coordinate input effective area in which the recursive reflecting portion is provided in the peripheral portion and the plurality of sensor units are provided in the plurality of corner portions is projected by the light projecting portions of the plurality of sensor units. The pointing position in the coordinate input device that is recursively reflected by the recursive reflecting portion and is calculated from the angle information corresponding to the light shielding portion by the pointing tool or the finger in the light amount distribution obtained by the light receiving portions of the plurality of sensor units The calculation method of
The light-shielding portion by the indicator or finger in the light quantity distribution in which the direct reflection light by the indicator or finger based on the light from the light projecting unit of one sensor unit is obtained from the light receiving unit of the one sensor unit. Determination based on angle information corresponding to a light-shielding part in a light receiving part of a sensor unit other than the one sensor unit, whether or not the direct reflected light influencing range affecting the light is instructed by the pointing tool or a finger Process,
When the determination unit determines that the direct reflected light influence range is instructed by the pointing tool or a finger, the calculation unit calculates one indication position from the light shielding range affected by the direct reflected light A method for calculating a designated position in a coordinate input device, characterized by comprising: When there are two light shielding portions in the light receiving portion of the one sensor unit, and the angle information corresponding to the light shielding portions in the light receiving portions of sensor units other than the one sensor unit corresponds to the direct reflected light influence range, 5. The method of calculating a designated position in a coordinate input device according to claim 4, wherein the judging means judges that the direct reflected light influence range of the one sensor unit is designated by the pointing tool or a finger. When there are two light-shielding portions in the light-receiving portion of the one sensor unit, and angle information corresponding to the light-shielding portions in the light-receiving portions of sensor units other than the one sensor unit does not correspond to the direct reflected light influence range, 5. The method for calculating a designated position in a coordinate input device according to claim 4, wherein the judging means judges that the outside of the direct reflected light influence range of the one sensor unit is designated by the pointing tool or a finger. The pointing position by the pointing tool or the finger with respect to the coordinate input effective area in which the recursive reflecting portion is provided in the peripheral portion and the plurality of sensor units are provided in the plurality of corner portions is projected by the light projecting portions of the plurality of sensor units. A computer as a coordinate input device for calculating from angle information corresponding to a light-shielding portion by the pointing tool or a finger in a light quantity distribution recursively reflected by the recursive reflecting portion and obtained by light receiving portions of the plurality of sensor units. A program for functioning,
Directly reflected light from the indicator or finger based on light from the light projecting unit of one sensor unit affects the light shielding part of the indicator or finger in the light amount distribution obtained from the light receiving unit of the one sensor unit. A determination means for determining whether or not the direct reflected light influence range is instructed by the pointing tool or the finger based on angle information corresponding to a light shielding portion in a light receiving portion of a sensor unit other than the one sensor unit;
When the determination unit determines that the direct reflected light influence range is instructed by the pointing tool or a finger, the computer serves as a calculation unit that calculates one indicated position from the light shielding range affected by the direct reflected light. Program to make it work.

Images