JPH0816308A - Ultrasonic coordinate input device - Google Patents

Abstract

PURPOSE:To always stably detect coordinates by immediately performing combination with another microphone when any defect signal such as a noise signal is detected at any one of both microphones or at both the microphones. CONSTITUTION:Just after a power source is turned on, two microphones to be used for default are decided, afterwards, coordinates are inputted from a coordinate indicator 1, and it is decided whether a noise detection circuit 11 detects noise in input data. When the noise is detected, microphone change processing is performed by a microphone change circuit 14. When no noise is detected, microphone coordinate calculating circuits 6-9 decide whether the coordinates are skipped or not and when the skip of coordinates is generated, the microphone change processing is performed by the microphone change circuit 14 similarly to the time of noise detection. When no noise is detected and no coordinate skip is detected, the microphone is not changed but that indicated coordinate is utilized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic coordinate input device for detecting a coordinate pointing position of the coordinate indicator based on an electromagnetic wave and an ultrasonic wave emitted from the coordinate indicator.

[0002]

2. Description of the Related Art Conventional coordinate input devices generally use a pen-shaped or cursor-shaped coordinate indicator to detect the coordinates of the input point on the tablet body by electromagnetic induction using a coil, or a resistive film. The coordinate position is detected by the change in the resistance value at one point on the tablet body pressed by, or the coordinate position is determined by the transmission time of the ultrasonic vibration transmitted from the coordinate indicator to the predetermined position. It is known to detect.

The configuration and operation of a conventional ultrasonic coordinate input device will be described below with reference to FIGS. 3 and 4. FIG. 3 is an explanatory diagram of an ultrasonic coordinate input device, and FIG. 4 is a circuit block diagram of a conventional ultrasonic coordinate input device.

In FIG. 3, 3A, 3B, 3C and 3D are microphones for receiving the ultrasonic signal transmitted from the coordinate indicator, and in the conventional structure, only two microphones 3A and 3B are used. . In FIG. 3, reference numeral 1 is a coordinate indicator, and a liquid crystal panel 4 of a main body (hereinafter referred to as a tablet main body) 2 is brought into contact with the tip of the coordinate indicator to input designated coordinates. At this time, the ultrasonic waves transmitted from the coordinate indicator are received by the microphones 3A and 3B.

FIG. 4 is a circuit block diagram of a conventional ultrasonic coordinate input device. The ultrasonic signal transmitted from the coordinate indicator 1 is detected by the microphones 3A and 3B provided on the tablet body 2. The electromagnetic wave signals simultaneously transmitted from the coordinate indicator are received by the coil 5 provided in the tablet body 2, and the output from the coil 5 is input to the electromagnetic wave receiving circuit 10.

Further, the microphone 3 which has received the ultrasonic signal
The outputs from A and 3B are input to the microphone coordinate interval calculation circuit 6 and the microphone coordinate interval calculation circuit 7. Noise detection circuit 1
1 receives the signals from the microphone distance calculation circuits 6 and 7, and determines whether the input signal is a coordinate instruction signal or a noise signal. When the determination result is a noise signal, this signal is sent to the noise data processing circuit 15 and processed so as not to affect the coordinate detection.

On the other hand, when it is determined that the determination result is the coordinate designation signal, this signal is sent to the coordinate calculation circuit 12 to calculate the designated coordinates.

[0008]

However, in the conventional structure, as shown in FIG. 3, for example, the operator may obstruct the space between the coordinate indicator 1 and the microphone 3A with his / her finger, or the microphone may be held by the operator depending on the state of use. In some cases, such as when it was covered, the accurate coordinate position could not be detected.

In addition, when one microphone fails,
There is a problem that the function of calculating the designated coordinates is lost. An object of the present invention is to solve the above-mentioned conventional problems and provide an ultrasonic coordinate input device capable of stably acquiring designated coordinates.

[0010]

In order to solve the above-mentioned problems, the present invention detects at least an ultrasonic signal from the coordinate indicator 1. Therefore, in addition to at least two microphones necessary for coordinate detection, at least One or more microphones are provided to solve the above problems.

That is, normally, the ultrasonic signal from the coordinate indicator 1 is detected by a combination of two microphones.
When there is noise detection in the noise detection circuit 11 and coordinate skip detection by the microphone coordinate calculation circuit, the microphone in use that has caused the abnormality is switched to a combination with another optimum microphone that can operate normally, and It is configured such that the designated coordinates are detected by an optimum combination of two microphones.

[0012]

In the ultrasonic type coordinate input device configured as described above, when noise is generated or the microphone is broken, it is possible to switch to another optimum combination of microphones, so that stable instructions can be given. You can get the coordinates.

[0013]

Embodiments of the present invention will be described below with reference to FIGS. As shown in FIG. 3, in this embodiment, four microphones 3A, 3B, 3C and 3D are provided on the tablet body.
Are provided, and the microphones 3A and 3 are provided by default.
B combination is selected.

At this time, an obstacle such as a finger enters between the designated coordinate of the coordinate indicator 1 and the microphone 3A, and the noise detection circuit 6 of FIG.
Even if the received signal is judged as noise or not as noise, coordinate skipping occurs in the microphone coordinate calculation circuit 6, and as a result, in the noise data processing circuit 15, these data are calculated as noise data and coordinate calculation is performed. Is processed so as not to affect.

At the same time, the noise data processing circuit 14 sends a signal to the microphone changing circuit, and the microphone changing circuit makes an optimum combination with a microphone other than the microphone that picked up the defective data, for example, the combination of the microphones 3C and 3D. select. The optimum method of selecting two microphones in the microphone changing circuit 14 is to select the one of the microphones that is the most effective as the continuous data (for example, the distance difference is the smallest) for the position coordinates that are continuously input, going back in the past. Select a combination.

Next, FIG. 2 shows a flowchart from the time when power is supplied. First, immediately after the power is turned on, the two microphones to be used by default are determined, and thereafter, the coordinate input from the coordinate indicator 1 is performed. In the next step, it is determined whether the noise detection circuit 11 has detected noise in the input data.

When noise is detected, the microphone changing circuit 14 performs a microphone changing process. If no noise is detected, the microphone coordinate calculation circuit determines whether or not there is a coordinate skip, and if a coordinate skip occurs, the microphone change circuit 14 performs the microphone change processing as in the case of noise detection. If noise and coordinate skipping are not detected, the designated coordinate is used without changing the microphone.

After receiving the electromagnetic wave signal from the coordinate indicator, the electromagnetic wave receiving circuit 10 generates a reference signal based on the electromagnetic wave signal, and the coordinate position is detected by delaying the ultrasonic signal with respect to the reference signal. The time is counted by a counter (not shown) or the like, and is calculated by the calculation performed thereafter.

[0019]

As described above, according to the present invention,
If a bad signal such as a noise signal is detected by either or both of the two microphones in use, it can be immediately combined with another microphone, so that it may be affected by external noise or the user There is an effect such that stable coordinate detection can be always performed without particularly limiting the operation state of.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an ultrasonic coordinate input device of the present invention.

FIG. 2 is a flowchart of an ultrasonic coordinate input device according to the present invention.

FIG. 3 is an explanatory view schematically showing the present invention.

FIG. 4 is a block diagram showing a configuration of a conventional ultrasonic coordinate input device.

[Explanation of symbols]

 1 coordinate indicator 2 tablet body 3A, 3B, 3C, 3D microphone 4 liquid crystal panel 5 coil 6, 7, 8, 9 microphone coordinate interval calculation circuit 10 electromagnetic wave reception circuit 12 coordinate calculation circuit

Claims (3)

[Claims] 1. A coordinate indicator for generating at least an ultrasonic signal, a plurality of microphones for receiving an ultrasonic signal from the coordinate indicator, and a combination of two microphones for indicating a designated position of the coordinate indicator. A microphone inter-coordinate calculation circuit for calculating, a noise detection circuit that receives an input from the microphone inter-coordinate calculation circuit, and performs noise detection for an ultrasonic signal from the coordinate indicator, based on the ultrasonic signal from the coordinate indicator In the ultrasonic coordinate input device configured with a tablet body having a coordinate calculation circuit for calculating the designated coordinates of the coordinate indicator, if noise detection or coordinate skipping occurs during the designated coordinate detection, the combination of microphones is changed. An ultrasonic coordinate input device, characterized in that a microphone changing means is provided. 2. The coordinate indicator generates an ultrasonic wave signal and an electromagnetic wave signal, the tablet body is provided with at least three or more microphones for detecting the ultrasonic wave signal, and two selected microphones among these microphones are provided. 2. The ultrasonic coordinate input device according to claim 1, wherein the ultrasonic wave signal is detected by using, and the designated coordinate is detected from the ultrasonic wave signal received using the electromagnetic wave signal as a reference signal. 3. A tablet body, which has at least three or more microphones for receiving ultrasonic signals, and which detects a designated coordinate by a combination of two microphones, has a microphone according to a reception state from a coordinate indicator. The ultrasonic coordinate input device according to claim 1, further comprising circuit means for changing a combination of the above.