JPH112853A - Photometry device for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact photometry device for a camera surely preventing external light which is unnecessary for photometry from entering at a low cost. SOLUTION: An incident light limiting member 33 preventing the unnecessary external light other than from a subject from being made incident is provided on the front surface of a photoreceptor 32 constituting the photometry device. A light shielding layer 30a by black printing process is formed on the inside surface of a front surface cover 30, and a transparent photoreceiving window 30b obtained by eliminating the layer 30a by the specified range of the periphery of the optical axis of the photoreceptor 32 is formed. The member 33 is a cylindrical member entirely formed of elastic black rubber, the front end edge is brought into press-contact with the cover 30, and the trailing end edge is brought into press-contact with the photoreceptor 32. A photoreceiving body diaphragm 33a limiting light made incident on the photoreceiving surface of the body 32 is formed on the trailing end edge where the member 33 is brought into contact with the photoreceptor 32.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photometric device for a camera, and more particularly to a photoreceptor of the photometric device for a camera.

[0002]

2. Description of the Related Art In order to achieve cost reduction and miniaturization, a low-priced, highly portable compact camera is designed to reduce the number of parts and assembly costs by unitizing the components into functions and reduce the internal space. Is used effectively. For example, photoreceptors constituting a photometric device for object brightness, or parts requiring high mounting accuracy, such as a finder lens, are mounted on a block-shaped finder substrate to form a unit, which is mounted on the top of the camera body. ing.

The photometric device mounted on the finder substrate as described above has a transparent photometric window for a certain range on a front cover provided on the front of the finder substrate in order to enhance the photometric accuracy by center-weighted photometry. The light incident on the photoreceptor is limited by disposing the photoreceptor at a considerable distance behind the front cover.

[0004]

However, in the above-described method, the thickness of the camera is increased.
This is a major obstacle to downsizing the camera. On the other hand, if the photometric window of the front cover forming the photometric device is brought closer to the photoreceptor in order to reduce the thickness of the camera, the intrusion of extraneous light unnecessary for photometric measurement will increase, and photometric accuracy will decrease. Problems arise.

Further, since the light-shielding layer on the inner surface of the front cover is formed by printing, there is a limit to increasing the dimensional accuracy of the light-metering window formed by not providing a part of this light-shielding layer. There is a limit to effectively restrict the incidence of external light unnecessary for photometry only by the window.

Further, since the size of each part of the finder substrate is formed with a certain margin in terms of assembly efficiency, a light source for auto-focus and a red-eye prevention lamp provided adjacent to the photometric device are provided. It is inevitable that some of the light such as enters the optical path of the photometric device.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a compact photometric device for a camera which reliably prevents intrusion of external light unnecessary for photometric accuracy at low cost. .

[0008]

In order to solve the above-mentioned problems, according to the present invention, a photoreceptor is installed behind a light-shielding window of a fixed size provided on a front cover of a camera, and the light-receiving member is passed through the photometric window. In a photometric device for a camera for measuring subject brightness by receiving subject light with the photoreceptor, between the front cover and the photoreceptor, a rear edge is pressed against a light receiving surface on a front surface of the photoreceptor, and a front edge is formed. An incident light limiting member is provided which is pressure-bonded to the back surface of the front cover and is provided integrally with a photoreceptor aperture for limiting the exposure range of the light receiving surface on the rear end side.

According to a second aspect of the present invention, the incident light limiting member is formed of an elastic body. In a third aspect of the present invention, the light receiving body is formed with respect to a horizontal optical axis passing through the center of the photometric window. The center of the stop is shifted vertically upward, and the incident light limiting member has a rotationally asymmetric shape with respect to the optical axis.

[0010]

FIG. 2 is a perspective view showing the appearance of a camera embodying the present invention. The camera 2 has an IX240 in which a photo film is stored in a plastic cartridge.
This is a compact camera that uses a type film cartridge. The camera 2 includes a front outer plate 4 that is mounted on a front side of a camera body 3 (see FIG. 3) in which a film cartridge is loaded and various photographing mechanisms are assembled.
a and a rear exterior plate 4b.

On the upper surface of the camera 2, there is provided a shutter button 6 which is half-pressed during focusing and deeply pressed during shutter release. On the front surface of the camera 2, a lens barrel 7, a light-emitting window 8 and a light-receiving window 9 for distance measurement, a light-metering window 10 for light measurement, an objective-side finder window 11, a red-eye reduction lamp window 12, a strobe light emission, and the like. A part 13 and the like are provided. On the back side of the camera 2, although not shown, an eyepiece side finder window, a liquid crystal panel on which various shooting information is displayed,
A zoom lever for changing the magnification of the lens barrel 7 as a zoom lens, a bottom cover for loading and unloading a film cartridge, and the like are provided.

FIG. 3 is an exploded perspective view showing the structure of the camera 2. The camera body 3 has a cartridge chamber 15 in which a film cartridge is loaded and a film in which a photographic film sent out from the film cartridge loaded in the cartridge chamber 15 is wound around a lens barrel 7 attached to the front center. And a winding chamber 16.

A take-up shaft for taking up a photographic film is rotatably arranged in the film take-up chamber 16, and the inside of the take-up shaft is a driving source for feeding the film. A motor is incorporated. A drive shaft 18 that engages with a spool of the film cartridge and rotates in a film feeding direction and a rewinding direction, and a gear 1 that rotates the drive shaft 18 is provided above the cartridge chamber 15.
A gear train 22, 9, 20, 21 is rotatably mounted. The gear train 22 is connected to a motor via a rotating shaft 23 coaxially mounted on the gear 21 and a gear train (not shown) incorporated at the bottom of the camera body 3.

An upper part of the camera body 3 holds a distance measuring and photometric element and a finder optical system, and a gear train 2 mounted on an upper part of the cartridge chamber 15.
A holding member 25 that supports the camera 2 is mounted, and a control board 26 on which a control circuit for controlling each part of the camera 2 is formed is mounted on the holding member 25. The holding member 25 is roughly divided into an AF / finder holding portion 28 which is a finder substrate to which various elements and a finder optical system are attached, and a gear supporting portion 29 which is a gear supporting plate for supporting the gear train 22. . In addition, this AF
A front cover 30 partially transparent is provided on the front side of the finder holding section 28 (see FIG. 2). Except for the transparent portion of the front cover 30, the inner surface of the front cover 30 is covered with a light-shielding layer 30a on which light-shielding printing is performed (see FIG. 1).

The AF / finder holding section 28 has a block shape, and a light receiving lens 31 for distance measurement is provided on the front surface thereof.
In addition, mounting openings 35, 36, and 37 are formed in which the photoreceptor 32 and the incident light limiting member 33 that constitute the photometric device of the present invention, and the red-eye reduction lamp 34 are respectively mounted. A light-tight cylindrical portion 38 is integrally formed behind the mounting opening 35 to which the light receiving lens 31 is mounted, and a light measuring body 39 for distance measurement is mounted behind the cylindrical portion 38.

An incident light restricting member 33 is provided on the front surface of the photoreceptor 32 constituting the photometric device to prevent unnecessary external light from other than the subject from being incident on the photoreceptor 32, which lowers the photometric accuracy. Have been. As shown in FIG. 1, the light receiving body 32 and the incident light limiting member 33 are attached.
The cylindrical portion 40 of the AF / finder holding portion 28 has a step 40a formed in the middle thereof, and the light receiving body 32 is mounted on the back side of the step 40a, and the incident light limiting member 33 is mounted on the front side of the step 40a. Can be

A light-shielding layer 30a formed by black printing is formed on the inner surface of the front cover 30 attached to the front side of the AF / finder holder 28. Only the corresponding parts
The transparent light receiving window 30b has no light shielding layer 30a in a certain range around the optical axis of the light receiving body 32.

The incident light restricting member 33 is a cylindrical member entirely formed of elastic black rubber, and its front edge presses against the front cover 30 and its rear edge presses against the photoreceptor 32, respectively. . At the rear end of the incident light restricting member 33 where the incident light restricting member 33 is in contact with the light receiving body 32, a light receiving body stop 33a for limiting light incident on the light receiving surface of the light receiving body 32 is formed.

As described above, the light receiving window 30b whose light transmission range is limited by the light shielding layer 30a and the photoreceptor stop 33a of the incident light restricting member 33 define the range of the reflected light from the subject as shown in FIG. Unnecessary external light outside the angle θ, which lowers the photometric accuracy, is prevented from entering the photoreceptor 32, and only the subject light within the range of the angle θ is allowed to enter.

A cylindrical portion 42 for mounting an objective lens unit 41 constituting a finder optical system is formed on the side of the mounting opening 36 of the photoreceptor 32. An opening 43 for the lens unit 41 is formed, and a prism 44 constituting a finder optical system is attached to the rear end. On the side of the cylindrical portion 42, a cylindrical portion 47 to which a light emitting element 45 for distance measurement and a light emitting lens 46 are attached is formed.

The AF / finder holder 28 is mounted on the upper part of the camera body 3 and has a light receiving lens 3 for distance measurement.
1, a light receiving body 32 for photometry, a lamp 34 for red eye reduction, an objective lens unit 41, and a projection lens 46 for distance measurement are provided with a light receiving window 9 for distance measurement, a photometry window 10 for photometry, and a lamp window for red eye reduction. 12, an object-side finder window 11, and a distance measuring light-emitting window 8 are arranged behind.

The gear support 29 has a plate shape.
It is integrally formed so as to protrude from the side of the cylindrical portion 38 of the F / finder holding portion 28 to which the light receiving lens 31 for distance measurement is attached. On an upper surface of the gear support portion 29, a zoom lever 49 used for zooming operation of the lens barrel 7 as a zoom lens is assembled. The zoom lever 49 is attached to a pin 50 erected on the upper surface of the gear support plate 29, and is swingable between a telephoto position and a wide-angle position sandwiching the neutral position. Also, this zoom lever 49
An elastic piece 51 for returning the zoom lever 49 rocked between the telephoto position and the wide-angle position to the neutral position is integrally formed.

On the upper surface of the zoom lever 49, a metal contact piece 53 for a zoom changeover switch is attached.
The metal contact piece 53 comes into contact with the control board 26 mounted on the upper part of the holding member 25, and swings together when the zoom lever 49 is swung to contact the conductive surface of the control board 26, thereby performing zoom switching. Turn the switch on and off.

The control board 26 is attached to the holding member 25 with two screws 55 and 56. Further, two flexible substrates 57 and 58 are sandwiched between a portion where the control substrate 26 and the holding member 25 are attached. One flexible board 57 is for connecting a control board 26 to a barcode reader provided on the film cartridge for reading barcode data. The other flexible substrate 58 is for connecting the control substrate 26 to a magnetic head for magnetically recording various data on the magnetic recording layer of the photographic film.

The flexible boards 57 and 58 and the control board 26 are formed with conductive portions, respectively.
When the control board is attached to the holding member 25 with the flexible boards 57 and 58 sandwiched therebetween, these conductive portions come into contact and are electrically connected.

The operation of the camera having the above configuration will be described. As shown in FIG. 1, photometry outside the angle θ, which is the range of the reflected light from the subject, is achieved by the light receiving window 30b whose light transmission range is restricted by the light shielding layer 30a and the light receiving member stop 33a of the incident light restricting member 33, as shown in FIG. Unnecessary external light that reduces accuracy can be prevented from being incident on the photoreceptor 32.
The light receiving window 30b and the photoreceptor stop 33a of the incident light restricting member 33 restrict the incidence of external light unnecessary for photometry. The distance from the window 30b can be shortened, and the camera can be made compact.

The light shielding layer 30 on the inner surface of the front cover 30
It is difficult to precisely maintain the size of the light receiving window 30b without error because it is difficult to accurately maintain the accuracy of the printing process a. However, the incident light between the light receiving body 32 and the light receiving window 30b of the front cover 30 is difficult. By providing the restricting member 33, even if the dimensional accuracy of the light receiving window 30b is slightly shifted, the incident light restricting member 33
As a result, unnecessary external light affecting photometry is reliably cut.

On the other hand, since the incident light restricting member 33 is formed of elastic rubber, the cylindrical portion 38 of the AF / finder holder 28 to which the incident light restricting member 33 is attached.
Even if there is some play in the dimensions without being formed by costly high-precision processing, the elasticity of the rubber ensures that the incident light restricting member 33 adheres tightly to the inner wall of the cylindrical portion 38 and swings in the cylindrical portion 38. Does not move.

Similarly, the front edge and the rear edge of the incident light restricting member 33 are firmly adhered to the front cover 30 and the photoreceptor 32, respectively, due to the elasticity of the rubber, even if there is some play in the dimensions. The AF / finder holding unit 2
By working the cylinder portion 38 with a slight play, the work becomes easier when the light receiving body 32 and the incident light limiting member 33 are assembled to the cylinder portion 38. Further, since the rubber forming the incident light restricting member 33 is black, irregular reflection on the inner surface of the incident light restricting member 33 is suppressed, and excellent photometric accuracy is maintained.

Incidentally, the incident light limiting member may be shaped as shown in FIG. The incident light restricting member 80 according to the second embodiment is provided such that the center of the photoreceptor diaphragm 81 on the photoreceptor (not shown) side is vertically shifted upward. Also, the incident light restricting member 80 has a gentle R surface only on the upper surface side so as to be rotationally asymmetrical with respect to the optical axis. Also in 84, the upper inner wall is an R-plane. As described above, by forming the photoreceptor diaphragm 81 of the incident light restricting member 80 so as to be shifted upward, low-weighted photometry can be performed at low cost. By shifting the position of the photoreceptor stop to an arbitrary position, it is possible to easily perform light measurement with emphasis on only a part of the subject.

In addition, by forming a gentle R surface only on the upper surface side of the incident light limiting member 80, in the assembling process,
When the incident light restricting member 80 is inserted into the cylindrical portion 84 of the AF / finder holder 83, the incident light restricting member 80 is not turned upside down. Since the incident light restricting member 80 is also formed of flexible rubber, the incident light restricting member 80 swings in the cylindrical portion 84 even if there is some play in the dimensions of the cylindrical portion 84. Without sticking to the inner wall, it is fixed.

In the above two embodiments, the incident light limiting member is made of rubber. Can be. In the above embodiment,
Although a compact camera has been described as an example, the present invention can be applied to, for example, a single-lens reflex camera or an instant camera.

[0033]

As described above, according to the present invention,
A photometric device for a camera that incorporates a photoreceptor behind a light-shielding window of a fixed size provided on a front cover of a camera and receives subject light passing through the photometric window with the photoreceptor and measures subject brightness. Between the front cover and the photoreceptor, the rear edge is pressed against the light-receiving surface of the front of the photoreceptor, the front edge is pressed against the back of the front cover, and the exposure range of the light-receiving surface is limited to the rear end side An incident light limiting member with an integrated aperture is provided to prevent external light unnecessary for photometry from entering.
It is possible to provide a compact camera photometric device that reliably prevents it at low cost.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view near a photometric device of a camera.

FIG. 2 is a perspective view showing the appearance of the camera.

FIG. 3 is an exploded perspective view partially showing a configuration of a camera.

FIG. 4 is an explanatory diagram showing a second embodiment.

[Description of Signs] 2 Camera 3 Camera main body 25 Holding member 26 Control board 28 AF / finder holding unit 29 Gear support unit 33 Incident light limiting member 33a Photoreceptor aperture

Claims (3)

[Claims] 1. A camera for incorporating a photoreceptor inside a light-shielding window of a predetermined size provided on a front cover of a camera, and measuring subject brightness by receiving the subject light passing through the photometry window with the photoreceptor. In the photometric device, between the front cover and the photoreceptor, the rear edge is pressed against the light receiving surface of the front surface of the photoreceptor, the front edge is pressed against the rear surface of the front cover, and the light receiving surface is exposed on the rear end side. A photometric device for a camera, comprising an incident light restricting member integrally provided with a photoreceptor aperture for restricting the light. 2. The photometric device for a camera according to claim 1, wherein said incident light limiting member is formed of an elastic body. 3. The method according to claim 2, wherein the center of the photoreceptor diaphragm is shifted vertically upward with respect to a horizontal optical axis passing through the center of the photometric window, and the incident light restricting member has a rotationally asymmetric shape with respect to the optical axis. The photometric device for a camera according to claim 2, wherein: