JPH0345940A - Warning display device in camera finder - Google Patents

Abstract

PURPOSE:To display a warning showing incapable state of photographing by arranging an electronic optical display element so as to cover the part of a finder screen, displaying the electronic optical display element at high density at the time that the conditions that focusing is not allowed or that exposure control is not correct for stroboscopic photographing are identified and covering the finder screen. CONSTITUTION:In a finder optical system 12, the electronic optical display element 15 is arranged so as to cover at least the part of the finder screen. When range-finding data detected by an autofocusing device 2 corresponds to closer range than the range which allows photographing or when correct exposure is not allowed for the stroboscopic photographing even when the stroboscopic photographing is performed, the electronic optical display element 15 is displayed at high density and at least the part of the finder screen is covered. Thus, the device surely informs a photographer of the abnormal conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a display device that actively hides a finder screen and displays a warning using an electro-optical display element such as a transmissive liquid crystal display element.

[Conventional technology]

2. Description of the Related Art Modern cameras utilize various electro-optical display elements, such as liquid crystal displays, whose light transmittance can be varied in response to applied electrical signals. Also, JP-A-60-10261
As shown in Japanese Patent Application No. 5, etc., there are also known devices in which a liquid crystal display is incorporated into the finder so that display data can be observed along with the subject image.

[Problem to be solved by the invention]

In a conventional viewfinder display device using such an electro-optical display, the display is installed outside the field frame so that the display does not overlap with the subject image observed through the finder. Therefore, it is necessary to secure space around the viewfinder to incorporate the display, which is disadvantageous in terms of compactness.

[Purpose of the invention]

The present invention has been made to solve the problems of the prior art as described above, and provides an in-finder warning display device that is advantageous in terms of installation space and can display a large and easy-to-understand display. The purpose is to

[Means to solve the problem]

In distantly related to the above object, the present invention arranges an electro-optical display element in the finder optical system so as to cover at least a part of the finder screen, and the distance measurement data detected by the autofocus device can be photographed at a close range. When the camera is compatible with shorter distances, or when the correct exposure is not obtained even with flash photography, the electro-optical display element displays a high density display to at least partially hide the viewfinder screen. This is what I did.

[Effect]

When the subject distance is too close or when proper exposure cannot be obtained even with flash photography, the electro-optical display element displays a wide space with high density, at least partially hiding the viewfinder screen, making it difficult for the photographer to Abnormal conditions can be reliably notified.

Embodiments of the present invention will be described below with reference to the drawings.

〔Example〕

In FIG. 2 showing the appearance of a camera using the present invention, a movable lens barrel 2 that can move forward and backward is built into the front of a camera body 1, and when a zoom knob 3 on the back side of the body is operated, it moves forward and backward in the optical axis direction. Change focal length. The movable lens barrel 2 has a built-in zoom lens as a photographic lens, but when not in use, its front surface is covered by a lens barrier 4 as shown. This lens barrier 4 can be opened and closed by operating an opening/closing knob 5 on the back side of the body.

Further, when the lens barrier 4 is opened, the barrier switch 6 is turned on. A shutter button 7 is provided on the top surface of the camera body 1, and a distance-measuring projecting/receiving window 8, 9, a finder window IO, and a strobe light emitting section 11 are provided on the front surface.

A real-image type finder optical system 12 shown in FIG. 3 is built in the back of the finder window 10. The finder optical system 12 includes, in order from the objective side, a parallax correction prism 13. Objective lens 14. Transmissive liquid crystal display board 15. Boropuri Dam16. It consists of an array of eyepiece lenses 17. The light flux that has entered the objective lens 14 through the prism 13 forms an image on the entrance surface 16a of the Porro prism 16, and the image is formed on the Porro prism 16. It is observed through the eyepiece 17. Therefore, if a field frame mark or the like is displayed on the incident surface 16a, it is possible to clearly observe the viewfinder image. Furthermore, since the liquid crystal display plate 15 is also arranged to coincide with the entrance surface 16a of the Porro prism 16,
The image displayed on the liquid crystal display board 15 is also observed with almost no difference in diopter from the finder image.

FIG. 1 schematically shows the control circuit of the camera and the display segment arrangement of the liquid crystal display panel 15. As shown in FIG. The transmissive liquid crystal display panel 15 consists of a total of 32 display segments 20a to 35a, 20b to 35b arranged symmetrically, and is driven by an LCD driver 38. These display segments can be driven independently according to the voltage applied from the LCD driver 38, and are transparent when not driven, and become highly concentrated and almost light-shielded when driven. Note that the LCD driver 38 has a built-in ROM 39, and the ROM 39 stores data for driving the liquid crystal display board 15 in a predetermined display pattern.

The microcomputer 40 refers to the program stored in the sequence ROM 41 and executes the camera operation sequence, that is, the lens barrier opening/closing mechanism 42. Release switch mechanism 43. AE circuit 44. AF mechanism 45. Shutter drive mechanism 46° Film feeding mechanism 47. Controls the operation of the strobe device 48. Note that various data used at this time are written to or read from the RAM 49 at any time.

The lens barrier opening/closing mechanism 42 opens and closes the lens barrier 5 described above, and inputs switching data of the barrier switch 7 associated with the opening/closing to the microcomputer 40. The release switch mechanism 43 detects the pressing operation of the shutter button 7 and inputs a half-press operation signal and a full-press operation signal to the microcomputer 40. The AE circuit 44 photometers the subject brightness and calculates the shutter speed corresponding to the photometered value. This camera uses a programmable shutter, and the exposure amount can be controlled simply by adjusting the shutter speed.

The AF device +145 receives a command from the microcomputer 40 and starts a distance measuring operation. As a result, near-infrared light for distance measurement is emitted from the light projection window 8 shown in FIG. 2 toward the subject, and when the reflected light is received by the light receiving window 9, distance measurement data corresponding to the subject distance is is obtained. Then, the photographing lens is controlled to extend to the focus position in accordance with this distance measurement data. Further, the distance measurement data obtained in this way is also used for Franschmatic control as will be described later.

The shutter drive mechanism 46 controls the opening and closing of the shutter blades according to the shutter speed calculated by the AE circuit 44 . In FIG. 4, which schematically shows the shutter drive mechanism 46, a pair of shutter blades 51a and 51b pivotally attached to a shutter board 50 constitute a program shutter that also serves as an aperture, and each has a slot formed therein. ing.

Pins 53a, 5 of the drive ring 52 are inserted into these slots.
3b are fitted, and when the drive ring 52 rotates clockwise against the spring bias, the shutter blades 51a and 5
1b rotates in the opening direction, and when the drive ring 52 reverses, each rotates in the closing direction.

The drive ring 52 is rotated by a stepping motor 56 via a gear train 54 and a gear train 55 formed in a portion thereof.

Further, as shown in the figure, in the closed state, the shutter blade 51a
, 51b partially overlap. The drive ring 52 rotates a predetermined amount and the exposure starts at the moment when the bin 57 turns on the timing switch 58, and the timing switch remains on during the exposure period.

The stamping motor 56 is driven by a motor driver 60. The motor driver 60 receives from the microcomputer 40 a driving clock pulse CK as well as a PF signal PR signal for determining the rotation direction. When the PF multiplier signal "IJ" and the PR signal are "0", the stepping motor 56 rotates forward and the shutter blade 51a
, 51b are rotated in the opening direction, and the PF multiplied signals rOJ, P
When the R signal is "rl", the shutter blade 51a.

51 is rotated in the closing direction. Note that when both the PF and PR signals are rQJ, the stepping motor 56 stops;
Rotation of the shutter blade also stops.

The shutter display counter 62 is cleared to a count value "0" at the moment the shutter button 7 is fully pressed, and then increases by a timer interrupt every 50 m5ec, for example.

The film feeding mechanism 47 not only feeds the film frame by frame each time shooting is completed, but also rewinds the film after shooting all frames of the film. Furthermore, the strobe device 48 has a low-brightness automatic flash function, and the AE circuit 44
When the shutter time calculated corresponding to the subject brightness becomes long enough to be easily touched during hand-held photography, a constant amount of illumination light is emitted from a strobe light emitting part 11 (with a constant guide number). Based on the distance measurement data obtained by the AF mechanism 45, the light emission trigger signal is supplied from the microcomputer 40 at the moment when the shutter blades 51a, 51b have an aperture diameter corresponding to the subject distance. This enables so-called flashmatic control in which the strobe emits light at an aperture that corresponds to the distance to the subject.

The operation of the camera having the above configuration will be explained below.

The flowcharts shown in FIGS. 5 and 6 represent processing accompanying a series of photographing operations. When the lens barrier 4 remains closed, all of the display segments 20a to 35a and 20b to 35b of the liquid crystal display board 15 are displayed with high density, and the viewfinder screen becomes completely black, making it impossible to observe the viewfinder screen. You can confirm in the viewfinder that it is not possible to take pictures. When the opening/closing knob 5 is operated to operate the lens barrier opening/closing mechanism 42, the lens barrier 4 is opened, and when fully opened, an ON signal is input from the barrier switch 6 to the microcomputer 40. As a result, the microcomputer 40
Since all display segments of the liquid crystal display panel 15 are made transparent via the CD driver 38, the viewfinder image can be observed through this, and it can be seen that the camera is ready for photographing.

After framing through the viewfinder, when the shutter button 7 is pressed halfway, the halfway press signal is input to the microcomputer 40 via the release switch mechanism 43, and the microcomputer 40 outputs an operation command signal to the AE circuit 44. The AE circuit 44 calculates the shutter speed of the program shutter in accordance with the subject brightness. The program shutter starts exposure by increasing the aperture diameter as the exposure time passes, corresponding to the brightness of the subject.
After that, the so-called triangular exposure mode enters the closing operation,
It operates in one of the trapezoidal exposure modes, in which the opening diameter is gradually increased and the opening diameter is maintained at a constant value for a predetermined period of time, and then the closing operation begins. However, when calculating the shutter time as described above, the opening diameter gradually increases. Both the time SA and the time S11 during which the predetermined opening diameter is maintained are calculated. Of course, in the triangular exposure mode, it becomes "S, -0". The shirt time data calculated in this way is stored in the microcomputer 40.
The data is fed back to the RAM 49 and stored at a predetermined address location.

When the shutter speed data is obtained, the microcomputer 40 refers to this data and determines whether flash photography is necessary. That is, regarding the times Sa and Sa calculated by the AE circuit 44, when the time 5IlO value becomes, for example, 40 m5ec or more, the value of the time Sa is stored as is, but the time Sll is limited to 40 msec, and the microcomputer 40 by RAM
A light emission flag "1" is set at a predetermined location 49.

Furthermore, when the time Sll is less than 40 msec, the light emission flag remains at "0" and non-strobe photography is performed.

During non-strobe photography, it is first determined whether the distance measurement data obtained by the AP mechanism 45 is appropriate. In general, a photographic lens has a closest photographing distance at which it can take pictures, and it is not possible to focus on objects that are closer than that.

Therefore, when the distance measurement data corresponds to an object closer than the closest shooting distance, focusing becomes impossible.
In this case, all segments of the liquid crystal display board 15 are displayed in black and the finder screen is hidden. This allows the photographer to confirm that there is an abnormal condition, and furthermore, the shutter button 7 is locked and cannot be pressed.

On the other hand, when the flash flag is set to "1" and flash photography is performed, the aperture diameter that provides the appropriate exposure for flash photography is determined from both distance measurement data corresponding to the subject distance and the strobe guide number. Further, based on this aperture diameter, the time SF (see FIG. 7) from the moment when exposure is started until reaching the aperture diameter is calculated.

After that, it is determined whether or not it is within the flashmatic interlocking range. In other words, if the distance measurement data corresponds to a subject that is too far away, and the flash is underexposed even if the flash is fired at the maximum aperture, it will be determined that the flash is outside the flashmatic range, and in this case, The entire surface of the liquid crystal display board 15 is displayed in black, and a warning is displayed that the photographing is inappropriate by hiding the viewfinder screen. After that, similarly to non-stroboscopic photography, it is determined whether the distance measurement data corresponds to something closer than the closest shooting distance, and if it is closer than the closest shooting distance, all segments of the liquid crystal display board 15 are displayed. is displayed in black to notify the photographer of the abnormal condition.

When the camera is within the AF interlocking range during non-stroboscopic photography, or when it is within the AF interlocking range and within the flash match interlocking range during flash photography, the process shifts to the process shown in FIG. 6, and the shutter button 7 is pressed. A shooting sequence is started by pressing the button fully. When the shutter button 7 is fully pressed, a full press signal is input from the release switch mechanism 43 to the microcomputer 40 . The microcomputer 40 holds this full-press signal as a release signal until exposure is completed, and starts the photographing sequence. At the start of the photographing sequence, the AF mechanism 45 is first activated, and the photographic lens is set at a focus position corresponding to the distance measurement data stored in the RAM 49, and then the shutter drive mechanism 46 is activated to perform exposure.

In addition, whether the light emission flag is "0" or "1" is
The operation of the shutter drive mechanism 46 is not affected.

The operation of the shutter drive mechanism 46 begins when the microcomputer 40 first supplies the motor driver 60 with a PF multiplier signal of "1" and the stepping motor 56 starts normal rotation. stepping motor 56
When the lens rotates forward by a predetermined amount, a pinhole is formed by the shutter blades 51a and 51b, and exposure is started. At the moment when this exposure starts, the timing switch 58 is turned on, and from this point on, measurement of the time SA is started, and the stepping motor 56 continues to rotate normally during that period. Therefore, the shutter blades 51a and 51b perform exposure while gradually increasing the aperture diameter.

After the elapse of time SA, the PF multiplied signals rl, to rQJ
Then, both the PF multiplied signal and the PR signal become rQJ, and the driving of the stepping motor 56 is stopped. At the same time, measurement of time S is started. Therefore, time S,
Until the time elapses, the shutter blades 51a and 51b maintain a constant aperture diameter, thereby performing exposure in the trapezoidal exposure mode. Of course, when the result of the exposure time calculation in the AE circuit 44 is 'Sg=0', the time S is not measured and exposure is performed in the triangular exposure mode.

When the measurement of time Sll is completed, the PR signal becomes "1" and the stepping motor 56 starts rotating in reverse. At the same time, the shutter blades 51a and 51b rotate in the closing direction,
Exposure is completed the moment the timing switch 58 is turned off. Even after the timing switch 58 is turned off, the stepping motor 56 continues to operate at the time S. After that, the PR signal also becomes "0" and the shutter blades 51a and 51b are restored to their initial state.

Note that when the light emission flag is "l", the shutter blades 51a and 51b are opened to the maximum opening, and the opening is 40m5.
The ec is driven to close after opening and stopping, but during the opening process, a strobe trigger signal is sent to the microcomputer 4.
0 to the strobe device 48. The generation timing of this strobe trigger signal is determined by the timing switch 5.
This is the moment when the time SF has elapsed from the moment when 8 is turned on, that is, the moment when the shutter blades f151a and 51b have an aperture diameter corresponding to the subject distance.

While the shutter drive mechanism 46 is driven as described above, the shutter display counter 62 performs a count-up operation every 50 m5ec. And the shutter display counter 62
Corresponding to the count value, a simulation display of the shutter operation is displayed on the liquid crystal display board 15 as shown in FIG. The pattern P is displayed in the display segments 20a,
20b.

22a and 22b are displayed at high density, and the display of pattern P2 is further performed by displaying the display segments 21a and 21b.
, 23a, 23b, 25a, 25b.

26a, 26b, 29a, 29b, 30a, 30b, 3
This is done by displaying 5a and 35b in high density.

Also, pattern P3. P can also be displayed sequentially as shown in FIG. 8 by displaying appropriate display segments arranged as shown in FIG. 1 with high density.

At the time when the simulation display of the shutter operation is completed, the entire liquid crystal display board 15 is displayed in black (pattern P). Then, in synchronization with the film feeding after the exposure display, a simulated display of film feeding is started. This film feeding display is performed, for example, by changing from pattern Q to pattern Q7 in FIG. 9 each time the film passes through a film perforation, and becomes fully transparent when one frame feeding is completed. In this way, when the liquid crystal display panel 15 becomes fully transparent and the entire viewfinder image can be observed, the next shooting is possible.
Similar to the shutter operation display described above, it is possible to display the display in the viewfinder without any disadvantage in terms of space and which is easy to observe.

In the embodiments described above, the liquid crystal display board 15 is composed of a plurality of display segments in order to display the shutter operation and film feeding synchronization, but it is simply outside the AF interlocking range or flashmatic interlocking range. If it is only necessary to display on the viewfinder that this is the case, it is sufficient to arrange one liquid crystal display segment so as to overlap at least a portion of the viewfinder screen. Furthermore, the display form is not necessarily limited to a completely light-blocking state, but may also be replaced by a translucent display or a blinking display.

Furthermore, display elements that can be applied to the present invention include, in addition to the above-mentioned liquid crystal display elements, light transmittance and transmitted color light that change in response to applied electrical signals (high concentration in a specific wavelength range, light transmission It is also possible to use an electro-optical display element, such as an electroluminescent display element, which exhibits wavelength selectivity. Further, the finder optical system incorporating such a display element is not necessarily limited to a real image type.

〔Effect of the invention〕

As described above, according to the viewfinder display device of the present invention, the electro-optical display element is arranged so as to cover at least a portion of the viewfinder screen, and it is possible to prevent focus adjustment while the sequence processing of the camera is being executed. Alternatively, when it is identified that exposure control during strobe photography cannot be performed properly, the electro-optical display element displays a high-density display to hide the viewfinder screen. This makes it possible to effectively display a warning indicating that photographing is not possible within the viewfinder screen, which is limited due to human pace.

[Brief explanation of drawings]

FIG. 1 is a block diagram schematically showing the circuit configuration of a camera to which the present invention is applied. FIG. 2 is an external view of a camera to which the present invention is applied. FIG. 3 is a perspective view showing an example of a finder optical system. FIG. 4 is a schematic diagram of the shutter drive mechanism. 5 and 6 are flowcharts showing the operational sequence of the camera to which the present invention is applied. FIG. 7 is a timing chart showing the operation of the camera to which the present invention is applied. FIG. 8 is an explanatory diagram showing an example of shutter operation display. FIG. 9 is an explanatory diagram showing an example of film feeding display. 12... Finder optical system 15... Liquid crystal display boards 20a to 35a, 2ob to 35b... Component 40... Microcomputer 46... Shutter drive mechanism 48... Strobe device 51a, 51b... Shutter blade 58... Timing switch 62 ...Shutter display counter.・Display segment No. 6

Claims (2)

[Claims] (1) In a camera with a built-in autofocus device, an electro-optical display element whose light transmittance is variable in response to an applied electrical signal is arranged in the finder optical system so as to cover at least a portion of the finder screen. , when the distance measurement data obtained by the autofocus device corresponds to a distance shorter than the closest distance that can be photographed, the electro-optical display element displays a high density display to hide at least a part of the finder screen. A warning display device in a camera viewfinder characterized by: (2) In a camera with a built-in strobe, an electro-optical display element whose light transmittance can be varied in response to an applied electrical signal is arranged in the viewfinder optical system so as to cover at least a portion of the viewfinder screen, and the strobe is A warning display device in the viewfinder of a camera, characterized in that when switching to photography, the electro-optical display element displays a high-density display to hide at least a part of the viewfinder screen when the flash photography is out of the interlocking range. .