JPH0256533A - camera - Google Patents

Abstract

PURPOSE:To obtain an easy-to-see display by providing a photometry circuit which has such sensitivity characteristics that the sensitivity is relatively higher nearby a display position than at any position and controlling display emitted light with the output of the photometry circuit. CONSTITUTION:This device is provided with a partial photometry means having such sensitivity characteristics that the sensitivity is relatively higher nearby the display position of the display device is relatively higher than at any other position, and the quantity of display light emission is controlled with the photometry output of the photometry means. Namely, a photometry sensor SPC 4 for averaged photometry is provided slightly inside the image in a finder visual field and further photometry sensors SPC 1, SPC 2, and SPC 3 for spot photometry centering three range finding points are arranged further inside the sensor SPC 4. Then, the partial photometric value nearby the range finding point is compared with the photometric value of the whole screen and a larger value is used as a photometric value for light emission quantity arithmetic. Consequently, various pieces of information which are superposed on the finder visual field light image by light emission have invariably proper brightness without reference to the brightness of the light image in the finder visual field and its light quantity distribution.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the adjustment of the amount of emitted light in a so-called active type superimposed display in which information is displayed by emitted light superimposed on an optical image in a finder of a camera.

[Conventional technology]

BACKGROUND ART Conventionally, it has been widely practiced to display photographing information such as shutter time, aperture value, and in-focus/out-of-focus state of automatic focus adjustment outside the viewfinder field of a camera. At this time, there is a known method of constructing an information display that is easy for the observer to see by detecting the brightness of the light image within the viewfinder's field of view, and then modulating the brightness of the display device to emit light to the same brightness as the image. .

For example, as shown in FIG.
(Aperture value) display LED row 1139 Focus status display LED 1
A camera display device having 14 is known. Note that 115 is a field frame for automatic focus adjustment. Regarding display devices for such cameras, the Japanese Patent Application Laid-open No. 60-8 proposed by the present applicant
Brightness modulation as in No. 3995 to finder field of view 111
It is desirable to perform this based on the overall average brightness. On the other hand, when measuring the brightness of a finder light image using a method such as partial photometry that is specifically sensitive to the central area, if that area happens to have a particularly bright or dark light intensity distribution, the displayed luminescence amount will be large ( If the display is too large or too small, it becomes difficult to see.This is because the display position is outside the viewfinder field of view, and the viewer's eyes react to the overall brightness of the finder light image while looking at the display light. It is from.

[Problem to be Solved by the Invention] However, the inventors have discovered that when a display section is within the field of view of the finder, the photometric value for brightness modulation should be determined based on a methodology different from the conventional one.

As an example of the display within the viewfinder field, for example, the 1st O
There is a multi-point distance measurement point display as shown in the figure. 2. Description of the Related Art A focus adjustment device that can detect focus at a plurality of different positions within a photographic screen is known. The simplest method is to arrange a plurality of conventionally used focus detection devices in parallel and select one of the detection results by some method to adjust the focus. Furthermore, various focus detection devices suitable for providing a large number of distance measurement points have already been proposed. When selectively adjusting the focus at a plurality of different positions like this, clearly displaying which distance measurement point is to be adjusted for focus greatly affects the operability in use. Although there are various configurations of the display method shown in FIG. It causes the light to appear to emit light.

Field of view frame 121 corresponding to the selected distance measurement point. 122.
One field frame out of 123 apparently emits light.

As the above-mentioned distance measurement point display is observed superimposed on the viewfinder light image, studies have revealed that the visibility of the display light is influenced by the local brightness of the finder light image at the display position. This tendency is particularly noticeable when the viewfinder light image at the display position is brighter than the average brightness, and the visibility of the display light is determined predominantly by local brightness.On the other hand, the viewfinder light image at the display position When the image is dark compared to the average brightness, the average brightness of the finder becomes a factor that determines the brightness of display light that is easy to see.

In other words, when displaying localized light emission by superimposing it on the viewfinder light image, the amount of light emission is calculated from the local photometric value of the brightness of the light image near the display position and the photometric value of the overall brightness of the viewfinder. Otherwise, it will not be possible to obtain a display that is always easy to read in a wide range of shooting situations.

In the conventionally known techniques, there was insufficient recognition of this point, which caused a serious problem in practice.

[Means for solving problems]

The present invention provides a display device within the viewfinder field of a camera that displays information using emitted light superimposed on an optical image in the camera's finder, in which the sensitivity near the display position of the display device is relatively higher than the sensitivity at other positions. It is an object of the present invention to provide a display device for a camera that has a photometric circuit with high sensitivity characteristics and that solves the above problems by controlling at least the light source drive circuit for the display emitted light using the output of the photometric circuit. . The present invention also provides a brightness modulation calculation algorithm that can always obtain optimal display brightness by combining photometric outputs having different photometric sensitivity distributions.

〔Example〕

The present invention will be explained in detail below.

FIG. 1 is a circuit diagram showing an embodiment of a camera equipped with a display device according to the present invention.

In the figure, PRS is a camera control device that includes, for example, a CPU (central processing unit), ROM, and RAM.

It is a 1-chip microcomputer with an A/D conversion function. The control device PR3 performs a series of camera operations such as an automatic exposure control function, an automatic focus adjustment function, and film winding/rewinding according to a camera sequence program stored in the ROM. For this purpose, the control device PR3 uses communication signals SO, SI, and 5CLK, and communication selection signals CLCM and C3DR.

The CDDR and CLDDR are used to communicate with peripheral circuits within the camera body and a control device within the lens to control the operation of each circuit and lens.

SO is a data signal output from the control device PR3, SI
is a data signal input to the control device PR3, and 5CLK is a synchronization clock of the signals So and SI.

LCM is a lens communication buffer circuit, and when the camera is in operation, it supplies power to the lens power supply terminal VL, and the selection signal CLCM from the control device PR8 is set to a high potential level (hereinafter abbreviated as "H", low potential level). The level is “L”
), it serves as a communication buffer between the camera and lens.

When the control device PR5 sets the selection signal CLCM to "H" and sends predetermined data from the communication signal SO in synchronization with the communication signal 5CLK, the buffer circuit LCM outputs the communication signal via the camera-lens communication contact. 5CLK.

Each SO buffer signal LCK and DCL is output to the lens. At the same time, the buffered signal of the signal DLC from the lens is output as the communication signal Sl, and the control device PR5 inputs lens data from Sl in synchronization with the communication signal 5CLK.

SDR is a focus detection line consisting of CCD etc.
This is a drive circuit for the sensor device SNS, and the signal C3DR is “
"H", communication signals So and SI are selected.

It is controlled by the control device PRS using 5CLK. The signal CK is the CCD driving clock φ1. The signal INTEND is a clock for generating φ2, and the signal INTEND is a signal that notifies the control device PR3 that the accumulation operation has ended.

SNS is a photoelectric conversion section of a so-called image shift detection and focus detection device. The photoelectric conversion unit SNS has three series of sensor arrays, two pairs of which are connected in series in the array direction, and generates photoelectric signal arrays corresponding to the three distance measurement points. That is, the sensor arrays corresponding to distance measuring point 1 are SAI and SBI, the sensor arrays corresponding to distance measuring point 2 are SA2 and SB2, and the sensor arrays corresponding to distance measuring point 3 are SA3 and SB3.

It may be considered that the focus detection optical image incident on the sensor array pair at each distance measurement point is formed by separate separator lenses, or it may be considered that they are formed by a common pair of separator lenses. The method for realizing this function is either publicly known or proposed by the applicant, and is not related to the gist of the present invention, so the details will be omitted. Further, the number of distance measuring points in this embodiment does not limit the present invention. Furthermore, the method of focus detection is not intended to limit the present invention (for example, it may be implemented using blur detection).

The output signal O8 of the photoelectric conversion unit SNS is the clock φ1゜φ2
It is a time-series image signal synchronized with
It is output to R3. The control device PR5 inputs the signal AOS from an analog input terminal, and in synchronization with the signal CK, uses an internal A/D conversion function to sequentially store it at a predetermined address in the RAM as a digital signal.

5AGC, which is also the output signal of the photoelectric conversion unit SNS, is
AGC (automatic gain control + Out
.

This is the output of the Ga1n Control) sensor, is input to the drive circuit SDR, and is used for storage control of the photoelectric conversion unit SNS.

5PCI to 5PC4 are photometric sensors that receive light from a subject via a photographic lens. The output group 5spc is input to the analog input terminal of the control device PR3, and after AD conversion, is used for automatic exposure control and brightness modulation of the viewfinder display according to a predetermined program. Each sensor SP
The output of C is logarithmically converted by a logarithmic compression diode D, converted to low impedance by an operational amplifier, and then sent to the control device PR8.
is input. FIG. 2 shows the photometric area division pattern of four SPCs. A condenser lens is disposed behind the pentaprism and above the eyepiece, and a patterned SPC plate is provided behind the condenser lens, so that the focusing plate and the SPC plate are placed in a substantially image-forming relationship. In the SPC pattern of this embodiment, a photometric sensor 5PC4 for average photometry is located slightly inside the image 111' in the viewfinder field of view, and further inside that is a photometric sensor 5PCI for spot photometry centered on the positions of three distance measurement points. 5PC2 and 5PC3 are placed.

DDR is a circuit for switch detection and external display, and is selected when the signal CDDR is "H", and the signals So and SI are selected.
, 5CLK by the control device PR3. That is, based on the data sent from the control device PR3, the display on the display member DSP of the camera is switched, and the on/off states of various operating members of the camera are notified to the control device PR3 by communication.

LDDR is a circuit for displaying information in the finder, and is selected when the signal CLDDR is "H" and displays the data signals So,
SI, control device PRS using synchronized clock 5CLK
Controlled by That is, the TLED for TV display is based on the data sent from the control device PR3.

ALED for AV display, APLED for focus display, LEDI for displaying selected focus point, LED2. Switch the display of LED3.

SWI and SW2 are switches that are linked to a release button (not shown), and when the release button is pressed in the first step, SW is activated.
1 is turned on, and then SW2 is turned on at the second stage of pressing. The control device PRS performs photometry and automatic focus adjustment when SWI is on, and performs exposure control and film winding when SW2 is on.

In addition, SW2 is a control device P which is a microcomputer.
Connected to the "interrupt input terminal" of R3, switch SW
Even when a program is being executed when I is on, an interrupt is generated by turning on switch SW2, and control can be immediately transferred to a predetermined interrupt program.

MTRL is for film feeding, MTR2 is for mirror up/
It is a motor for down and shutter spring charging,
Forward rotation and reverse rotation are controlled by respective drive circuits MDRI and MDR2. Control device PR3 to MDRI, MDR
The signal MIF input to 2.

MIR, M2F, and M2R are signals for motor control.

MCI and MG2 are magnets for starting the movement of the front and rear shutter curtains, respectively, and are energized by the signals SMGI, 5MG2, and amplification transistors TRI and TR2, and the shutter control is performed by the control device PRS.

- Note that the switch detection and display circuit DDR, motor drive circuits MDRI and MDR2, and shutter control are not directly related to the present invention, so detailed explanations will be omitted.

The signal DCL input to the lens control circuit LPR3 in synchronization with the clocks L and CK is transmitted from the camera to the lens FLNS.
This is command data for the lens, and the operation of the lens in response to the command is determined in advance. The lens LPR3 analyzes the command according to a predetermined procedure, and determines the operation of focus adjustment and aperture control, and the operation status of each part of the lens (driving status of the focusing optical system, driving status of the aperture, etc.) and various parameters from the output DLC. (open F number, focal length, coefficient of defocus amount versus amount of movement of the focusing optical system, etc.).

In the embodiment, an example of a zoom lens is shown, and when a focus adjustment command is sent from a camera, the focus adjustment motor LMTR is driven by signals LMF and LMR according to the drive amount and direction sent at the same time. Then, the optical system is moved in the optical axis direction to adjust the focus. The amount of movement of the optical system is monitored by the pulse signal 5ENCF of the encoder circuit ENCF, and is calculated by a counter in the control circuit LPR3, and when the predetermined movement is completed, the control circuit LPR3 itself outputs the signal L.
MF and LMR are set to "L" to brake motor LMTR.

Therefore, once the focus adjustment command is sent from the camera, the camera control device PR3 does not need to be involved in lens driving at all until the lens driving is completed. Furthermore, the configuration is such that it is possible to send the contents of the counter to the camera if there is a request from the camera.

When an aperture control command is sent from the camera, a stepping motor DMTR, which is known for driving an aperture, is driven in accordance with the number of aperture stages sent at the same time. In addition,
Stepper motors are open-controlled and do not require an encoder to monitor operation.

ENCZ is an encoder circuit attached to the zoom optical system, and the control circuit LPR3 receives a signal 5ENCZ from the encoder circuit ENCZ to detect the zoom position. Lens parameters at each zoom position are stored in the control circuit LPR8, and when requested by the camera-side control device PR3, the parameters corresponding to the current zoom position are sent to the camera.

The information display device in the finder of this embodiment is shown in FIG. In other words, T composed of 7 segment LEDs
V display 112, AV display 113, focus status display LED lamp 114, and three distance measurement point displays 121°122, 12
It has 3. The distance measurement point displays 121, 122, and 123 are formed by forming fine prisms in the display shape on the matte surface of the focusing plate, and the cross section of the focusing plate is enlarged as shown in FIG. That is, a fine prism 33 is formed on the matte surface 32 side of the focusing plate 31. A Fresnel lens 34 is formed on the opposite side of the focusing plate 31. Under normal conditions, the imaging light beam that enters the photographic lens, is reflected by the main mirror, and reaches the focusing plate is refracted by the fine display prism 33.
As the light is scattered and deflected so that it does not enter the viewer's pupil, only the areas where the prisms are formed are visible in the dark based on the Schlieren principle.Therefore, the prism formation pattern is perceived by the viewer as a black display.However, illumination light 3
5 is irradiated at a predetermined angle from an illumination light source LED (not shown), it is deflected by a fine prism 33 and travels in the direction of arrow 36, that is, in a direction perpendicular to the focusing plate surface, so that a regular ray of light enters the viewer's pupil. direction, and the prism forming portion appears to emit bright light depending on the color of the illumination light. If an illumination light source is provided for each of the plurality of distance measuring point display sections and each of them is locally illuminated, one distance measuring point display prism can be caused to emit light independently. It should be noted that the illumination light that has entered the matte portion that is not the fine prism forming portion is diffused by the matte surface and follows the arrow 37.
Since this angle does not reach the roof surface of the pentaprism, it does not enter the observer's pupil.

FIG. 4 shows the optical arrangement around the pentaprism 41.

The display illumination light 35 emitted from the illumination light source LED is partially deflected by the fine prism on the upper surface of the focusing plate 31, and is emitted onto the roof surface 41b of the pentagonal prism.

Unnecessary illumination light becomes a light ray 45 and is absorbed by the suminuri surface 41a of the pentaprism. In the figure, 42 is a diopter lens, 4
3 is a photometric condenser lens, and 44 is a photometric sensor.

The basic operation of this embodiment will be explained based on the flowchart of FIG. After the switch SWI closes during the first stroke of the shutter release button and power is turned on to the camera's electrical circuit system, the ROM in the control device PR3
AE subroutine and A according to the program stored in
F subroutines are called alternately. Here, the conceptual flow and calculation method of the AE subroutine will be shown.

When the AE subroutine is called, the four photometric SPs
The output value of C is sampled and held in step (001), and AD converted in step (002). The exposure control mode is detected in step (003), and if it is automatic exposure mode, the process branches to step (004). In step (004), data such as the aperture f-number of the lens required for automatic exposure calculation is detected through communication with the lens control circuit LPR8, and in step (005), setting values for TV, AV, etc. are detected, and in step At (006), automatic exposure calculation is performed. The details of the automatic exposure calculation will be omitted since they are not the gist of the present invention.

In step (007), the TVV display 112. outside the viewfinder field of view. AV table display 113 Calculate the amount of gold emitted light. This calculation method is known. For example, using the Bv4 signal output from the sensor 5PC4 that covers most of the screen, the LED light emission duty cycle η may be determined as a function η=η(BV4) (1). For example, as shown in Fig. 6(a), η is a constant below a predetermined BV value BVa and above BVbV, and BVb>BV>BVa (D range is continuously variable, Fig. 6(b) A simplified step-like function such as It is not preferable to control the display luminescence amount using the photometric value.In this embodiment, it is preferable to control the display luminescence amount using the photometric value mainly from the sensor 5PC4, and the sensors 5PC1 to 5PC3 are used only as subordinates.Next In step (OOS), the out-of-field LED display device is controlled based on the calculated LED light emission value.

In this embodiment, the finder information display circuit LDDR is selected by setting the signal CLDDR to H level, and the display value and light emission value of the ALED for TV display (7) TI, ED, and AV display is selected using the data signal SO. is sent from the control device PR3 to the display circuit LDDR, and the display circuit LDDR
controls the light emission of the display LED based on the received data.

In step (009), it is detected which of the three distance measurement points is the focus adjustment target. The distance measuring point may be selected manually or automatically. For example, an automatic selection method is known in which the distance measuring point where the object is located closest to the camera is selected. Since the distance measurement point has already been selected in the AF subroutine, the detection in this step is performed by referring to the contents of the flag set by the AF subroutine. In the next step (010), the amount of LED light emitted for display within the viewfinder field of view is calculated. In this case, unlike the case of visibility display, the outputs of the sensors 5PCI-3 are actively utilized. One calculation method in this embodiment is as follows. Let the BV values of the sensors 5PC1 to 4 be Bv1 to Bv4. For example, when the selected ranging point is ranging point 1, BVX=max (BV H, BY 4) (2
a) η=η(BVX) Calculate the amount of LED light emission using (2b). That is, the partial photometric value BV near the distance measurement point and the photometric value BV4 of the entire screen are compared, and the larger one BVX is used as the photometric value for light emission amount calculation. Thereafter, the light emission duty cycles of LEDs 1 to 3 are determined using BVX. The method of calculating equation (2b) at this time may be the same as that of equation (1) or that shown in FIG. However, as a result of examination, it has been found that when BV and BV4 are extremely different, it becomes slightly difficult to see the viewfinder, so it is more desirable to determine the amount of light emitted from both the partial photometry value and the average photometry value, etc. . The weighting ratio between BV and BV4 is α>β when BV,>BV4, BV,<BV4
When , let α be β. Furthermore, as a very simplified configuration, the effects of the present invention can also be achieved in brightness modulation based only on partial photometric values.

Note that it is preferable that equation (2b) relating the photometric value and the amount of light emitted light not change linearly, but exponentially, as shown in FIG. 7.

[Other Examples]

The present invention is also useful in a camera equipped with a focus detection device having only one distance measuring point 130 as shown in FIG. Conventionally, the rangefinder frame display of single-lens reflex cameras with a focus adjustment function often uses a black display that takes advantage of the light scattering effect of microprisms, but this type of display device has a dark viewfinder (
It is easy to use when it is dark, so it is easier to use when it is dark.Also, the function of the in-focus indicator lamp 114, which was conventionally provided outside the viewfinder field of view, can be replaced by the light emitting light that indicates the distance measurement point.For example, By configuring the electrical flow so that the AF point display blinks slowly during focus adjustment, lights up continuously when in focus, and blinks at a rapid rate when focus cannot be detected, the light image of the subject can be seen in the viewfinder. The camera can be superimposed and visually check the in-focus state of the camera while observing, making it possible to realize a camera that is very easy to use.In this case as well, the present invention, which determines the amount of display light emission using partial photometry values around the display section, is extremely effective. Conventionally, the applicant has proposed a photometer for a camera with one distance measuring point, which has a sensor SPC pattern in which the viewfinder field of view is divided into six, as shown in Fig. 8. By averaging the logarithmically compressed BV ratio output of the SPC, a substantially averaged photometric value is obtained.On the other hand, since the spot photometric sensor 5PC81 and the partial photometric sensor 5PC82 are arranged at the center of the screen, these sensors 5PC81 ~86 B Vs
Using the +86 value and the average measured value, the display luminescence value is determined by calculation based on equations (2) and (3). For example, in the case of the distance measurement point display 130, BVX=max(BVa+
, BVs+-86), and in the case of the distance measuring point display 132, BVX = max (BV82. BV+n
-as).

In addition, when the apparent light emission of the AF point display also serves as an indication of the focus state, it is easier to understand by using a light source of two or more different colors and using different illumination colors depending on the operating state of the focus adjustment device. Display is obtained. For example, it may be possible to use different colors such as orange during focus adjustment, green when in focus, and red when focus cannot be detected. In this case as well, it is effective to adjust the amount of light emitted according to the brightness of the subject light image and its light amount distribution.

The present invention is generally effective for devices that display information by superimposing it on a light image within the field of view of a finder by emitting light.

Even if the display device does not use refraction using a microprism, it may use reflection from a microprism, or it may insert a light-emitting substance such as electroluminescence into the finder optical system. It may be. Furthermore, the type of display information is not limited to distance measurement point display; for example, even if it is a TV, AV display, or various warning displays, it may be locally localized, and
The present invention can be effectively used as long as the configuration has a photometric means that can obtain a partial photometric value in the vicinity of that position.

In the case of photometry near the display position of the present invention, when the distance measurement point is displayed,
It is possible to substitute the output value of the focus detection sensor. Normally, a photometric sensor outputs logarithmically compressed output to increase latitude, but a focus detection sensor outputs a linear output, so it requires some modification. Let Ai be the output of the focus detection sensor array (eg, 5AI in FIG. 1). The sensor array consists of N pixels, and the SAI output is A
It is assumed that it consists of time-series outputs of I, . . . AN. Take the sum of N pixels and Ao = ΣAt
If (4) is the photoelectric output of the virtually connected sensors, the value divided by the accumulation time T int is proportional to the amount of subject light incident on the entire area of the sensor array SAI, so λ = A o / T tnt
(5) When this value λ is digitally or analog-logarithmically converted, a photometric value can be obtained in which the focus detection sensor SAI is equivalently regarded as a photometric sensor.

Advantageously, the partial photometric value can be obtained from the output of the focus detection sensor, since the invention can be practiced without a dedicated partial photometric sensor. In particular, in the case of distance measurement point display, since the focus detection sensor is located at a position equivalent to the display position, it is well compatible with the present invention.

〔Effect of the invention〕

As explained above, according to the present invention, the various information displays that are superimposed on the viewfinder field of view light image and are displayed by emitting light always have appropriate brightness and are easy to see, regardless of the brightness of the light image within the viewfinder field of view and its light intensity distribution. A display device for a camera is obtained. Further, according to the present invention, since the display is improved, the operability of automatic functions such as the automatic focus adjustment function of the camera is significantly improved, and it is possible to construct a camera that is easy to use.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a camera according to an embodiment of the present invention. FIG. 2 shows a photometric division pattern of a camera according to an embodiment of the present invention. FIG. 3 shows a display element of a camera according to an embodiment of the present invention. FIG. 4 is an optical path diagram of a display system of a camera according to an embodiment of the present invention. FIG. 5 is a flowchart of a camera according to an embodiment of the present invention. FIG. 6 shows an example of a brightness calculation method for a camera according to an embodiment of the present invention. FIG. 7 shows an example of a brightness calculation method for a camera according to an embodiment of the present invention. FIG. 8 shows a photometric division pattern of another embodiment of the present invention. Figure 9 shows the viewfinder display of a conventional camera. FIG. 10 is a viewfinder display of a camera according to an embodiment of the present invention.

Claims (3)

[Claims] (1) In a camera's viewfinder display device that displays information using emitted light, which is superimposed on the optical viewfinder image of the optical viewfinder that confirms the camera's shooting screen, the sensitivity near the display position of the display device is It is characterized by having a partial photometry means having a sensitivity characteristic relatively higher than the sensitivity at other positions, and further comprising a light source drive circuit that controls the amount of display light emitted by the photometry output of the photometry means. Camera display device. (2) The display device according to claim (1), wherein a partial photometric value and an average photometric value are compared, and the drive circuit is controlled mainly based on the larger value. (3) The display device according to claim 1 or 2, wherein the display indicates the position of a focus detection point of a focus detection device.