JP3026653B2 - Display control device in viewfinder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling a display in a viewfinder of a camera.

[0002]

2. Description of the Related Art Conventionally, a camera is configured to display an image in a finder using a light emitting diode or the like so that a photographer can recognize a shutter speed or the like when operating the camera. When such a display is performed during the shutter release, the light of the light emitting diode reaches the film surface,
Fogging may occur in the film. So conventionally,
To prevent fogging of the film, the light emitting diode is turned off at the same time as the shutter is released, and the light emitting diode is turned on again when the winding of the film is completed.

[0003]

However, according to the structure in which the light emitting diode is turned off during the shutter release operation as described above, there is a problem that the display disappears for a long time, and it is difficult for the photographer to see the display in the viewfinder.
In particular, in the continuous shooting mode in which a plurality of pictures are continuously taken, the display remains off during the shutter release, so that there is a problem that it is difficult to determine the shutter speed. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a display control device in a finder that does not cause film fogging and that makes it easier to view the display in the finder.

[0004]

SUMMARY OF THE INVENTION A display control device in a finder according to the present invention includes a means for turning on a light for displaying an image in a finder, a means for detecting opening of a shutter, and a means for substantially opening a shutter. Means for interrupting the lighting by the lighting means only during a certain period.

[0005]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
FIG. 1 shows a control circuit of a camera to which one embodiment of the present invention is applied. The control circuit includes a microcomputer (CPU) 10 for controlling the entire camera, a microcomputer (DPU) 20 for controlling photometry and the like, a microcomputer (IPU) 30 for controlling display and the like, and a photographic lens. Microcomputer (lens C
PU) 40. Of these, the lens CPU 40
Only the photographic lens is provided, and the others are provided in the camera body.

The CPU 10 performs various sequence controls, AF
Operation, exposure calculation, etc. are performed. For this reason, the CPU 10 has an EE circuit 11 that generates a pulse synchronized with the narrowing-down operation.
And a switch circuit 12 for inputting signals from various switches such as a photometric switch and a release switch, and motor drive circuits 13 and 14. The motor drive circuit 13 drives the mechanical charge motor 15,
The motor drive circuit 14 is for driving a film winding (wind) motor 16 and an AF motor 17. The CPU 10 also has an E ² PROM 18 for storing information such as the number of films and various correction values.
And a plurality of magnets 19 for electrically holding the shutter or releasing the locked state of the mirror, respectively.

The DPU 20 has a CCD as a distance measuring sensor.
The DPU 20 is connected to a photometric IC 22 that outputs a voltage signal corresponding to the luminance of the subject, and the DPU 20 performs a photometric operation and acts as an interface for the CCD 21. A display device (LED) 23 for displaying various information in the viewfinder is provided on the DPU 20 and the CPU 10.
Is connected.

[0008] The IPU 30 includes a display device (LCD) 31 for displaying various information outside the camera body,
A flash circuit 32 and a switch circuit 32 for switching between exposure control in a program mode and a manual mode are connected.

The lens CPU 40 is an IPU on the camera body side.
The IPU 30 is connected to the IPU 30 to exchange information data of various lenses with the IPU 30, and to perform various calculations based on the data. A motor drive circuit 41 and a switch circuit 42 are connected to the lens CPU 40. The motor drive circuit 41 is for electrically driving the power zoom motor 43, that is, the photographing lens, and the switch circuit 42 is for performing control such as mode switching between power zoom and manual zoom.

Next, control of display in the viewfinder during shutter release will be described with reference to FIGS. 2 is a flowchart showing a program of a shutter release operation, FIGS. 3 and 4 are flowcharts showing a program of a film winding process, and FIG. 5 is a timing chart showing a sequence of a shutter release.

The shutter release operation program shown in FIG. 2 is started when the release switch is turned on (A in FIG. 5). 60m in step 101
The s timer is started. This timer determines the time (symbol B) for the slide plate for controlling the aperture to move from the open aperture position to the minimum aperture position.
Next, at step 102, the shutter magnet (1
The first shutter (stMg, 2ndMg) is turned on (reference C), the shutter is held in a closed state, the release magnet (release Mg) is turned on (reference D), and the locked state of the mirror is released.

In step 103, the mirror-up operation is started (symbol E), and the focusing operation is started. In this narrowing-down operation, in step 104, E
The E circuit 11 (FIG. 1) is started, and the counting of the EE pulse (symbol F) is started. The EE pulse is output according to the narrowing-down operation. When the number of EE pulses reaches a predetermined value, in step 105, the EE magnet (EEM) is output.
g) is energized for 5 ms. As a result, the slide plate, that is, the diaphragm stops at a predetermined position, and the diaphragm value is determined.

In step 106, it is determined whether or not 60 ms has elapsed since the start of the timer in step 101. When 60 ms has elapsed, the shutter magnet (1stMg) is turned off in step 107 (reference numeral 1).
C) The front curtain runs (reference H). Then step 111
Then, the light emitting diode (LED) displayed in the viewfinder is turned off.

If it is determined in step 112 that the set shutter release time has elapsed, in step 113, the shutter magnet (2ndM
g) is turned off (reference 2C), and the trailing curtain runs (reference I). If it is determined in step 114 that the trailing curtain has been driven, the light emitting diode displayed in the viewfinder is turned on in step 115, and the program proceeds to the film wind processing program (FIGS. 3 and 4).

In FIG. 3, at step 121, the charge motor is started, and the mirror down (reference J) and the shutter charge (reference K) are started.
At 22, the wind motor is activated to start winding the film. Next, at step 123,
The ms timer is started, and in step 124, the charge motor and the wind motor are pulse-driven (duty ratio control) (references L and M). By this pulse driving, the rotation of the charge motor and the wind motor is gradually accelerated. In step 125, step 1
If it is determined that 20 ms has elapsed from the start of the timer in step 23, the pulse driving ends, and in step 126, the charge motor and the wind motor are driven by DC (references N and O).

In step 131, as will be described later, 100 is used for recognizing the end of the film at the time of film winding.
The ms timer is started. Then, step 1 of FIG.
At 32, it is determined whether or not the wind pulse has changed, and while the change is detected, 1 is set at step 133.
Reset the 00ms timer and step 13
At 4, it is determined whether or not the winding has been completed. When the winding of the film is completed, in step 135, the wind motor is stopped. And step 1
After the completion signal (symbol P) from the charge completion switch is detected in 36, the charge motor is stopped in step 137, and the power is turned off.

On the other hand, if no change in the wind pulse is detected in step 132, step 141
In the following, it is determined whether or not the film has reached the end. That is, if the completion signal (symbol P) from the charge completion switch is detected in step 141, the charge motor is stopped in step 142, and if the completion signal is not detected, immediately in step 143, step 131 is executed. Or, it is determined whether 100 ms has elapsed since the execution of 133, and
When it is determined that s has elapsed, in step 144, the wind motor is stopped. Then, after it is confirmed in step 145 that charging has been completed, the charging motor is stopped in step 146, and the flow proceeds to film end processing.

As described above, in the present embodiment, the display in the viewfinder is displayed until the traveling of the rear curtain is completed (step 114) after the shutter curtain (1stMg) is turned off and the front curtain runs (step 107). The light emitting diode is configured to be turned off. That is, the lighting of the display in the viewfinder is interrupted only during the period when the shutter is substantially opened (the period indicated by reference numeral Q in FIG. 5).

FIG. 6 shows a light-emitting diode constituting a main part of the display device 23 in the finder, and switch circuits 41 and 42 for controlling turning on and off of the light-emitting diode. These switch circuits 41 and 42 are composed of transistors, and the first switch circuit 41 is connected to the CPU 10 and the second switch circuit 41.
Are connected to the DPU 20 respectively. Each of these switch circuits 41 and 42 outputs an ON signal when a predetermined command signal is input, and the display device 23 is turned on when an ON signal is input from both switch circuits 41 and 42. To emit light.

The CPU 10 normally has the first switch circuit 4
1 for the DPU 20
Outputs an ON command signal to the second switch circuit 42 based on a signal input from the IPU 30. These switch circuits 41 and 42 are turned on before the shutter release operation, that is, the display device 23 is lit at the start of the release operation. During this release operation, the DPU 20 continues to output an ON command signal to the second switch circuit 42, but when the shutter is opened, the CPU 10 outputs an OFF command signal to the first switch circuit 41, As described above, the result display device 23 is turned off during the exposure.

As described above, the display device 23 in the finder is used.
Is turned off only during the period when the shutter is substantially open, and is turned on during the other periods. Therefore, the light-off period of the display device 23 is shorter than before, and the display in the viewfinder is easy to see. In the continuous shooting mode, the display does not remain off during the shutter release operation and is displayed during periods other than when the shutter is open, so that it is easy to check the shutter speed and the like. Since the display device 23 is turned off while the shutter is open, there is no possibility that film fogging will occur.

[0022]

As described above, according to the present invention, it is possible to obtain an effect that the display in the viewfinder can be easily viewed without causing film fogging.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a circuit configuration of a camera having a display control device in a finder according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a program of a shutter release operation.

FIG. 3 is a flowchart showing a first half of a film wind processing program.

FIG. 4 is a flowchart showing a latter half of a program of a film wind process.

FIG. 5 is a timing chart showing a shutter release sequence.

FIG. 6 is a diagram showing a switch circuit for controlling a display device.

[Explanation of symbols]

 23 Display device

Claims (1)

(57) [Claims] 1. A lighting device for lighting a display in a viewfinder, a means for detecting opening of a shutter, and a means for interrupting lighting by the lighting means only while the shutter is substantially opened. A display control device in a finder.