JPH09265117A - Automatic focusing camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact automatic focusing camera by simplifying the constitution thereof. SOLUTION: This automatic focusing camera is obtained by arranging a main mirror 4 and a sub-mirror 5 observing an object at the central part of the optical axis of a photographing lens in a mirror box 3, forming an aperture part for range-finding 3a in an optical path reflected on the mirror 5 at the bottom part of the box 3 and arranging a disposing part for a dimming module on the more object side than the aperture part 3a so that light reflected from a film can be received. Besides, it is provided with a range-finding module 1 provided with a range-finding sensor 13 and a dimming module 2 provided with plural dimming sensors. Then, an incident aperture part 1e is faced to the aperture part 3a and the module 1 is arranged so that the sensor 13 is positioned on the object side. Besides, the plural dimming sensors are arranged to be near to the aperture part 3a and the sensor 13 so as to be almost symmetric on the upper side of the sensor 13 by interposing the central line of a photographic picture frame.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a main mirror in a mirror box and a sub-mirror for observing an object in the center of the optical axis of a photographing lens, and a distance measuring opening in the sub-mirror reflection optical path at the bottom of the mirror box. The present invention relates to an autofocus camera in which a light control module disposing portion is arranged on the subject side of the opening and the reflected light of the film can be received.

[0002]

2. Description of the Related Art Conventionally, a main mirror is rotatably provided in a mirror box, and a central portion of the main mirror is formed so that light from a subject can be transmitted therethrough. A sub-mirror for observing the subject in the center is arranged so as to be folded and housed, and a distance-measuring opening is formed in the sub-mirror reflection optical path at the bottom of the mirror box, and a dimming module arrangement portion is located closer to the subject than the opening. There is known an auto-focus camera in which is arranged so that the reflected light of the film can be received.

[0003]

However, in the above-described autofocus camera, since the main subject is usually located in the central portion of the photographing screen, the dimming sensor of the dimming module is usually used in the central portion of the photographing screen. In addition, the dimming sensor receives weak reflected light from the film surface and dims the light. Will be placed.

On the other hand, the distance measuring sensor of the distance measuring module is arranged at a position optically equivalent to the film surface through the distance measuring optical receiving system from the distance measuring opening provided at the bottom of the mirror box. Since the light control module and the distance measuring module are directly attached to the mirror box, it is necessary to adjust or replace them in the assembly process, the repair process, and the like. Especially in the distance measuring module, it is necessary to set the sensor desired for the subject on the surface orthogonal to the center axis of the taking lens, and set it under the mirror box together with the fine adjustment mechanism that finely adjusts the four corners of the surface of the distance measuring sensor. Was.

Therefore, in the conventional example, when the dimming module needs to be replaced after the assembling and adjusting, the distance measuring module needs to be readjusted by the fine adjustment mechanism, and these assembling or In order to easily carry out repairs, both of them are arranged independently at a position where they can be replaced with each other with a space between them, which has been a bottleneck for downsizing.

In view of the above circumstances, an object of the present invention is to provide a compact autofocus camera with a simple structure. Another object of the present invention is to provide an autofocus camera with improved workability in assembling. Another object of the present invention is to provide an autofocus camera that can improve the distribution characteristic of strobe light control and improve the S / N ratio of the light control signal.

[0007]

According to the present invention, a main mirror and a sub-mirror for observing an object at the center of the optical axis of a photographing lens are arranged in a mirror box, and distance measuring is performed in the sub-mirror reflection optical path at the bottom of the mirror box. In an autofocus camera that opens an opening and arranges a dimming module disposition part closer to the subject side than the opening to enable reception of reflected light from a film, an L-shaped cross section is formed from the entrance opening. The distance measuring module is provided with a distance measuring module having a distance measuring sensor on the side opposite to the entrance opening provided in the distance measuring optical path, and the light entrance module is provided at the distance measuring opening. The distance measuring sensor is located on the object side, the distance measuring module is arranged, and the plurality of light control sensors are arranged so that the center line of the photographing screen is above the distance measuring sensor. Nde configured by arranged close to the distance measuring opening and the distance measuring sensor to be substantially subject.

With this structure, the distance measuring sensor provided on the side opposite to the incident opening in the distance measuring optical path of the distance measuring module provided in the L-shaped cross section from the incident opening is used. The distance measuring opening and the distance measuring sensor are located closer to the subject than the distance measuring sensor opening so that the plurality of light control sensors are substantially symmetrical to each other with the center line of the photographic screen sandwiched above the distance measuring sensor. Since the distance measuring module and the light control module can be arranged in the vicinity of the sensor, the compact autofocus camera can be provided in which the distance measuring module and the light control module can be arranged in the vicinity of the distance measuring opening.

Further, it is preferable that the light control module is arranged directly on the bottom of the mirror box, and the distance measuring module is arranged on the bottom of the mirror box via a mount. With this structure, the distance measuring module is mounted on the mount. Therefore, when the dimming module is replaced, the distance measuring module is removed together with the mounting base, so that it is not necessary to readjust the mounting position of the distance measuring module even after the adjustment is completed.

Further, it is preferable that the light control sensor of the light control module is arranged so as not to receive the reflected light on the lower side of the photographing screen. The upper part of the subject is photographed on the lower side of the photographing screen, and the lower part of the subject is photographed on the upper side. Since the light control module measures diffused light reflected from the film surface, the amount of light is weak on average. When strong light from the upper part, which is the back light of the subject, that is, from the sky enters the weak light amount, the light becomes noise and the S / N ratio deteriorates. Therefore, the S / N ratio is improved by cutting the light from the sky.

Further, the dimming sensor of the dimming module is Ys / Ys, where Yf is the vertical length of the photographic screen and Ys is the vertical length from the upper end of the photographic screen corresponding to the viewing angle of the dimming sensor. It is preferable to set and set Yf = 0.5 to 0.75.

According to this structure, the length Ys in the vertical direction from the upper end of the photographing screen corresponding to the viewing angle of the light control sensor is 5
It can be set to 0% to 75%, and noise due to light from the sky can be removed to improve the S / N ratio.

Further, the dimming sensor of the dimming module is Xs / Xf = 0, where Xf is the lateral length of the photographing screen and Xs is the lateral length of the photographing screen corresponding to the viewing angle of the dimming sensor. It is preferable to set it to 0.8-1.

With this configuration, when Xs / Xf = 1, about 70% of the photographic screen including the central portion of the photographic screen where the effect of the sky is cut is observed, and the average photometric output is obtained. If Xs / Xf = 0.8, you can measure the output of spot-like photometry of about 55% of the shooting screen including the central part of the shooting screen part where the effect of the sky is cut. You can

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be exemplarily described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, and are merely illustrative examples. Only.

FIG. 1 is a sectional view of a mirror box used in the present invention, showing a basic configuration showing a state where a main mirror is returned to a photographing standby position, and FIG. 2 is a mirror box used in the present invention. FIG. 3 is a cross-sectional view showing a configuration in which a main mirror is raised to a photographing position, and FIG.
FIG. 4 is a front view of the mirror box, FIG. 4 is a sectional view taken along the line AA of FIG. 1, FIG. 5 is a view taken along the line BB of FIG. 1, and FIG. 6 is a side view showing a mounted state of the distance measuring module. Is a bottom view of the mirror box showing the mounting state of the distance measuring module, and FIG. 8 is a light quantity distribution diagram on the film surface observed by the light control sensor.
(A) shows a plane pattern, (b) shows the intensity of light quantity in a graph, FIG. 9 shows the light quantity distribution on the film surface observed by the dimming sensor, and (a) shows two sensors. Is located at the maximum distance and (b) is located at the minimum distance between the two sensors. FIG. 10 is a basic circuit diagram used in the autofocus camera according to the present invention.

In FIG. 1, a main mirror frame 11 to which a main mirror 4 is attached is provided in a mirror box 3 so as to be rotatable about a shaft 11a in a counterclockwise direction by applying a rotation return force (not shown). Thus, the main mirror 4 has returned to the illustrated shooting standby position. A pin 9a is projectingly provided on a mirror drive plate 9 which is rotatable coaxially with the shaft core 11a and which is rotated by a drive mechanism (not shown), and the pin 9a abuts the lower edge 11b of the main mirror frame 11. In contact with each other, the main mirror frame 11 is provided so as to be rotatable clockwise.

A sub-mirror 5 is implanted in the main mirror frame 11 and a sub-mirror mounting plate 10 is rotatably arranged in a clockwise direction with a shaft center 10a as a center of rotation so as to be rotatable. A pin 10b is provided at one end of the plate 10 in contact with the cam surface 9b of the mirror driving plate 9.

The central portion of the main mirror 4 becomes a half mirror, and a part of the light from the subject is reflected upward, but a part of it is transmitted to the distance measuring opening 3a formed in the mirror box 3 by the sub mirror 5. Is reflected.

The main mirror 4 constructed as described above is rotated clockwise through the pin 9a and the lower edge 11b of the main mirror frame 11 when the mirror drive plate 9 is rotated clockwise, as shown in FIG. Thus, it reaches the upper stop position as the shooting position and stops. In the process, the sub-mirror mounting plate 10, which has been given the turning habit in the clockwise direction, comes out of sliding contact between the cam surface 9b of the mirror driving plate 9 and the pin 10b, and the sub-mirror 5
Covers the central portion of the main mirror 4, which is a half mirror, and is folded up on the back surface of the main mirror 4 as shown in FIG. 2 to block the reverse incident light from the finder section 14.

When a predetermined exposure time elapses, a shutter (not shown) is closed, the mirror driving plate 9 is rotated counterclockwise, the main mirror 4 is lowered, and the sub-mirror mounting plate 10 is moved.
Pin 10b comes into contact with the cam surface 9b of the mirror drive plate 9 and returns to the photographing standby position in FIG. In this way, the main mirror 4 and the sub mirror 5 are configured.

On the other hand, on the bottom surface of the mirror box 3, there is provided a dimming module opening 3b in which the dimming module 2 is arranged on the object side near the distance measuring opening 3a. The dimming module 2 is made of synthetic resin, is provided with recesses 2R and 2L on which the dimming sensors 12R and 12L of the photodiodes are mounted, and mounting portions 2b and 2c (FIGS. 4 and 5). It is configured so that it is inserted into the opening 3b from the side of the bottom surface 3c of the box bottom portion and is screwed by the mounting portions 2b, 2c.

The distance measuring module 1 is formed as a light receiving optical system and forms an image forming lens 27 facing the distance measuring opening 3a.
L-shaped crank-shaped portion 1 having an opening 1e in which
a (FIG. 6), mounting arms 1b, 1c, 1d (FIG. 7) extending from the crank-shaped portion 1a, and a distance measuring sensor 13 provided at the end opposite to the opening 1e. It

The distance measuring module mounting base 6 for mounting the distance measuring module 1 is mounted like a shelf on the lower surface 3c of the bottom of the mirror box with screws (FIG. 3). The rectangular opening 6a and the light control sensor 12R are mounted on the shelf surface. A missing portion 6b is provided to avoid contact with the lower portion of 12L (FIG. 7). The opening 1e of the distance measuring module 1 is inserted into the opening 6a of the mounting base 6 and faces the distance measuring opening 3a of the mirror box 3, and the mounting arms 1b, 1c, 1d interpose an adjusting spring 7 therebetween. To the mounting base 6 with the adjusting screw 8.

A force acts on the mounting arms 1b, 1c, 1d in a direction away from the surface of the mounting base 6 by the adjusting spring 7. Therefore, by twisting or loosening the adjusting screw 8 of the arm portion, the light receiving surface of the distance measuring sensor 13 can be accurately adjusted so as to be orthogonal to the optical axis of the photographing lens. To adjust this surface, place a surface having a reference pattern at an appropriate reference distance from the camera, read the output of the distance measuring sensor, compare it with the reference output, and remove the screws on the arms 1b, 1c, 1d. The fine adjustment is performed, but the details are omitted because they are not directly related to the present invention.

Since this embodiment is constructed in this way, it is provided from the entrance opening 1e on the side opposite to the entrance opening 1e in the distance measuring optical path of the distance measuring module 1 having an L-shaped cross section. The distance measuring sensor 13 is located closer to the object side than the distance measuring opening 3a of the mirror box 3, and the plurality of light control sensors 12R and 12L have the center line of the photographing screen above the distance measuring sensor 13. Since the distance measuring opening 3a and the distance measuring sensor 13 can be arranged close to each other so that they are substantially symmetrical to each other, the distance measuring module 1 and the light control module 2 are close to the distance measuring opening 3a. A compact autofocus camera that can be arranged is provided.

Further, the present invention is a dimming sensor 12R, 12
If a dimming module 2 in which L is incorporated and a mounting base assembly in which the distance measuring module 1, the module adjusting spring 7, the adjusting screw 8 and the like are mounted in the mounting base 6 are prepared, the dimming module 2 and the By incorporating the mounting base assembly, it is possible to provide an autofocus camera with improved workability in assembling, and simplify management and storage of members.

Further, this embodiment is based on the light control module 2 described above.
Is disposed directly on the bottom of the mirror box 3, and the distance measuring module 1 is disposed on the bottom of the mirror box 3 via the mounting base 6, so that the dimming module 2
When replacing the distance measuring module 1, the distance measuring module 1 is removed together with the mounting base 6, so that the distance measuring module 1 can be easily carried out and readjustment is not necessary even after the mounting position of the distance measuring module 1 is completed. .

FIG. 10 is a basic circuit diagram used in the autofocus camera according to the embodiment configured as described above. The CPU (central processing unit) 20 includes a photometric circuit 21 having a photodiode 25 as a photometric element, a distance measuring circuit 22 having a CCD sensor as a distance measuring sensor 13, an AF driving unit 23 for driving a photographing lens, a film winding and a shutter. A sequence driving unit 24 for controlling driving, driving of a main mirror, and the like, a dimming circuit 25 for sending a light emission stop signal to a strobe 26 are connected, and the photodiodes 12R, 12L are dimming elements.

The dimming circuit 25 of the basic circuit configured as described above generally has a photodiode connected between the input terminals of an operational amplifier and an integrating circuit connected between the output terminal of the operational amplifier and the anode of the photodiode. It is composed of a circuit and a comparison circuit connected to the output terminal of the operational amplifier. Then, the dimming circuit 25 causes the photocurrent generated by receiving the light emitted by the strobe by the photodiode to flow into the integrating circuit, and feeds back so as to erase the counter electromotive voltage of the photodiode to stop the strobe. It acts to send out a signal. Therefore, by increasing the photocurrent for a given integration capacitor, the S / N
The ratio can be improved.

The upper part of the subject is photographed on the lower side of the photographing screen, and the lower part of the subject is photographed on the upper side. Since the light control module measures diffused light reflected from the film surface, the amount of light is weak on average. When strong light from the upper part, which is the back light of the subject, that is, from the sky enters the weak light amount, the light becomes noise and the S / N ratio deteriorates. Therefore, if the dimming sensor of the dimming module is arranged so as not to receive the reflected light on the lower side of the photographing screen, the light from the sky can be cut off, and S /
The N ratio is improved.

FIG. 8 is a light quantity distribution diagram on the film surface observed by the light control sensor. FIG. 8A shows a plane pattern,
(B) shows the intensity of light in a graph. In the case of the present embodiment, as shown in FIG. 8, assuming that the vertical length Yf of the photographing screen is 24 mm, the dimming sensor 12 is approximately Ys = 18 from the upper end of the photographing screen between the viewing angle lines L1 and L2 of the dimming sensor 12.
mm section (b) and the width of the shooting screen about Xf = 36
The section (a) of mm is observed and arranged so as to receive the diffused reflected light of the film surface. In addition, the light control sensor 12
About Ys from the top of the shooting screen between the viewing angle lines L1 and L2
= 18 mm, the sum of the light output power is calculated as (S1 + S
2), and the total sum of the light amount outputs in the section approximately Ys = 12 mm from the upper end of the photographic screen between the viewing angle lines L1 and L3 of the light control sensor is S1, the relationship between the area S1 and (S1 + S2) in (b) is , S1 + S2 = 7S2 +, S
1 = 6 S2 is slightly stronger, and S1 is 6 / compared to (S1 + S).
7 = 85% optical output will be delivered.

Therefore, the dimming sensor 12 of the dimming module has a vertical length Yf of the photographing screen, and a vertical length Y from the upper end of the photographing screen corresponding to the viewing angle of the dimming sensor.
If s is set, Ys / Yf = 0.75 can be used with a light output up to 85% when Ys / Yf = 0.75 is set as the maximum light output by setting Ys / Yf = 0.75 to 0.75.
Further, with this configuration, the vertical length Ys from the upper end of the photographing screen corresponding to the viewing angle of the light control sensor can be set to 50% to 75% from the upper end, and noise due to light from the sky is removed. The S / N ratio can be improved.

FIG. 9 shows the light quantity distribution on the film surface observed by the dimming sensor, where (a) shows the maximum distance between the two sensors and (b) shows the distance between the two sensors. Is located at the minimum distance. In (a), the dimming sensors 12R and 12L of the dimming module 2 have center-to-center Rm.
If ax = 16 mm is set, the horizontal length of the shooting screen is Xf, and the horizontal length Xs of the shooting screen corresponding to the viewing angle of the light control sensor is Xs / Xf = 1.
In the case of Xs / Xf = 1, the photographing screen portion Vo formed by Ys and Xf, which is the influence of the sky as shown in FIG. 8, is formed.
About 70% of total light quantity distribution V including the central part
The average photometry can be performed by receiving the light amount of (V is approximately 0.7 Vo).

Further, in (b), the light control module 2
The dimming sensors 12R, 12L of Rmin = 10
When Xs' / Xf = 0.8 is set to mm, the light amount of the total light amount distribution V'of about 55% including the central portion of the photographing screen portion Vo in which the influence of the sky is also cut is received (V 'Is approximately 0.55 Vo), and spot-like photometry can be performed.

As described above, in the present embodiment, a plurality of dimming sensors are used so as not to receive the direct light from the sky, and the influence of the reflected light from the sky is eliminated. Can be cut, and good photometry with an improved S / N ratio can be performed.

[0037]

As described above in detail, according to the present invention, the distance measuring module 1 is formed with the light receiving optical path having an L-shaped cross section, and the light is incident on the mirror box facing the distance measuring opening formed in the mirror box. The distance measuring sensor is provided at one end and the distance measuring sensor is provided at the other end, and the distance measuring sensor is arranged so as to be located closer to the subject side than the distance measuring opening of the mirror box. An optical sensor is provided, and the dimming sensor is arranged above the distance measuring sensor in close proximity to the distance measuring opening and the distance measuring sensor so as to be substantially symmetrical with the center line of the photographing screen interposed therebetween. Therefore, the distance measuring module and the light control module can be arranged close to the distance measuring opening, and a compact autofocus camera is provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a mirror box used in the present invention, which is a basic configuration diagram showing a state in which a main mirror is returned to a shooting standby position.

FIG. 2 is a cross-sectional view of a mirror box used in the present invention, which is a configuration diagram showing a state in which a main mirror is raised to a shooting position.

FIG. 3 is a front view of a mirror box.

4 is a cross-sectional view taken along the line AA of FIG.

5 is a view taken along the line BB of FIG.

FIG. 6 is a side view showing a mounted state of the distance measuring module.

FIG. 7 is a bottom view of the mirror box showing a mounted state of the distance measuring module.

FIG. 8 is a light intensity distribution diagram on the film surface observed by the light control sensor, in which (a) shows a plane pattern and (b) shows the intensity of light as a graph.

9A and 9B show light amount distributions on a film surface observed by a light control sensor, where FIG. 9A shows the maximum distance between two sensors, and FIG. 9B shows the minimum distance between two sensors. It is located in.

FIG. 10 is a basic circuit diagram used in the autofocus camera according to the present invention.

[Explanation of symbols]

 1 Distance Measuring Module 2 Light Control Module 3 Mirror Box 4 Main Mirror 5 Sub Mirror 6 Mounting Base 7 Adjustment Spring 8 Adjustment Screw 9 Mirror Drive Plate 10 Sub Mirror Mounting Plate 11 Main Mirror Frame 12 Light Control Sensor 13 Distance Measuring Sensor 14 Finder 15 Film 20 CPU 21 Photometry circuit 22 Distance measurement circuit 23 Distance measurement drive circuit 24 Sequence drive unit 25 Light control circuit 26 Strobe

Claims (5)

[Claims] 1. A main mirror and a sub-mirror for observing an object in the center of the optical axis of a photographing lens are arranged in a mirror box, and a distance measuring opening is formed in the sub-mirror reflection optical path at the bottom of the mirror box. In an autofocus camera in which the light control module disposition part is arranged on the subject side of the opening so that the reflected light of the film can be received, in the range-finding optical path provided in an L-shaped cross section from the entrance opening, A distance measuring module having a distance measuring sensor on the side opposite to the entrance opening; and a light adjusting module having a plurality of light adjusting sensors, wherein the entrance opening faces the distance measuring opening, and the distance measuring The sensor is located on the subject side, the distance measuring module is arranged, and the plurality of dimming sensors are substantially symmetrical to each other with the center line of the photographing screen above the distance measuring sensor. Autofocus camera, characterized in that arranged above and close to the distance measuring opening and the distance measuring sensor. 2. The autofocus camera according to claim 1, wherein the dimming module is arranged directly on the bottom of the mirror box, and the distance measuring module is arranged on the bottom of the mirror box via a mount. . 3. The autofocus camera according to claim 1, wherein the dimming sensor of the dimming module is arranged so as not to receive the reflected light on the lower side of the photographing screen. 4. The dimming sensor of the dimming module is Ys / Ys, where Yf is the vertical length of the shooting screen and Ys is the vertical length from the upper end of the shooting screen corresponding to the viewing angle of the dimming sensor. The autofocus camera according to claim 3, wherein Yf is set to 0.5 to 0.75. 5. The dimming sensor of the dimming module is Xs / Xf = 0, where Xf is the lateral length of the photographing screen and Xs is the lateral length of the photographing screen corresponding to the viewing angle of the dimming sensor. The autofocus camera according to claim 1, wherein the autofocus camera is set to 0.8-1.