JPH0326500Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is a light receiving device for photometry of a camera, more specifically, a reflection photometry device of a single-lens reflex camera, in which the light receiving element for photometry has a light distribution characteristic. Regarding equipment.

2. Description of the Related Art Three types of photometry modes for cameras are conventionally known: partial photometry, average photometry, and center-weighted photometry. Each of these metering modes has its own advantages and disadvantages, so in general, depending on the subject conditions or shooting intention, for example,
Partial photometry and average photometry are selected for use, or center-weighted photometry, which is intermediate between the two, is used.

By the way, a conventional photometric light receiving device for a single-lens reflex camera that allows selective use of partial photometry and average photometry is configured as shown in FIG. 1, for example. That is, in FIG. 1, before the shutter release, the movable observation mirror 2 of the camera body 1 is lowered into the photographing optical path at an angle of 45 degrees, and the light that has passed through the photographic lens 3 passes through the movable observation mirror 2. It splits into two directions at 2. Most of the light transmitted through the photographic lens 3 is reflected upward by the movable observation mirror 2 and is guided to a piston screen 5, a pentaprism 6, and a finder eyepiece 7, which are located at a position conjugate with the film 4. A light-receiving element 8 for average photometry is provided in the viewfinder eyepiece, and the light-receiving element 8 measures the subject light in an average photometry mode. On the other hand, out of the light that has passed through the photographic lens 3, the light that is close to the optical axis is transmitted to the half mirror section of the movable observation mirror 2.
After passing through the half mirror section 2a, it is reflected by the photometry mirror 9 attached to the movable observation mirror 2, and then reflected by the photometry light receiving element 10 provided outside the photographing optical path below the mirror 9. is guided through the condensing lens 11. In this way, the light receiving element 10 for partial photometry performs partial photometry on the light that is focused on the center of the film 4 out of the light reflected from the subject.

However, when the light receiving element 8 for average photometry is provided in the viewfinder section as in the above configuration, reverse incident light from the viewfinder eyepiece 7 may become a problem, or depending on the type of piston screen 5.
This was not preferable because the EE accuracy could be affected. Further, providing the two photometric light receiving elements 8 and 10 at different positions has the disadvantage that the configuration becomes complicated.

Therefore, it has been proposed to allow more photographic light to pass through the half mirror portion 2a and to also perform average photometry using the partial photometry light receiving element 10 (Japanese Patent Laid-Open No. 55-4095). but,
In this device, it is necessary to switch the condensing lens 11 by moving it in the optical axis direction according to each photometry mode, and therefore, a mechanical switching means must be provided to switch and move the condensing lens 11. In addition to the fact that the structure is inevitably complicated, there are also drawbacks such as the fact that it is difficult to achieve a state of perfect average photometry or partial photometry simply by switching and moving the lens 11.

In view of the above points, the purpose of the present invention is to provide a light-transmitting element that has a curved surface that regulates the angle of acceptance of light to some of the light-receiving parts in a single-chip photometric light-receiving element in which a plurality of light-receiving parts are integrally formed. It is an object of the present invention to provide a photometric light receiving device for a camera configured by arranging members.

Hereinafter, the present invention will be explained based on the illustrated embodiments.

FIG. 2 is a sectional view of a photometric light receiving device for a camera showing an embodiment of the present invention. In Figure 2,
Inside the camera body 21 of the single-lens reflex camera,
A movable observation mirror (hereinafter referred to as observation mirror) 22, which is entirely formed of a half mirror, has its back edge supported by a movable mirror frame 23, and has a support shaft attached to a side wall (not shown) of the mirror box. 24 so as to be rotatable. On the back side of the movable mirror frame 23, a photometric reflector 26 is rotatably attached to the mirror frame 23 by means of a support shaft 25. This reflecting plate 26 is placed in a position where the observation mirror 22 blocks the photographing optical path as shown in the figure.
When descending at an angle of 45 degrees, the film 27 is opened at a predetermined angle with respect to the mirror 22 with its front reflecting surface facing forward and slightly downward.
and is located in front of the shutter curtain 28, and when the observation mirror 22 rotates and rises to a position 22A outside the photographing optical path shown by the two-dot chain line, it is rotated so as to overlap the same mirror 22. 26A. As shown in FIG. 3, at the center of the front surface of the photometric reflector 26, the subject light that passes through the photographic lens 29 and is focused and imaged on the center of the film 27 or shutter curtain 28 is placed. A specular reflection portion 26a is formed in a range that can receive the luminous flux. Further, the entire surface of the front surface of the reflector plate 26 excluding the specular reflection portion 26a is exposed to the photographic lens 29 and the film 27
Alternatively, a milky-white diffuse reflection portion 26b is formed to diffuse and reflect the object light directed toward the entire surface of the shutter curtain 28.

As shown in FIGS. 2, 4, and 5, outside the photographing optical path below the observation mirror 22, a light-transmitting element 30 for photometry and a light-transmitting element for giving light distribution characteristics to the light-receiving element 30 are provided. A member 31 is provided. The photometric light receiving element 30 is arranged facing the photometric reflecting plate 26 so that it can receive the reflected light from the photometric reflecting plate 26. This photometric light receiving element 30
consists of a silicon photodiode, etc., and as shown enlarged in FIG. 4, its light-receiving surface is divided into three parts in the horizontal direction, and there are three light-receiving parts 30a, 30b, and 30c from which photometric output can be taken out independently. are integrally formed. Three light receiving sections 30a, 30
b, 30c, the central light receiving section 30a serves as a light receiving section for partial photometry, and the light receiving sections 30 on both sides thereof
b and 30c are light receiving sections for average photometry. The light-transmitting member 31 provided in front of the light-receiving surface of the photometric light-receiving element 30 is made of plastic, glass, or the like, and the surface facing the photometric reflector 26 is formed into a curved surface. That is, the translucent member 31
The central light receiving section 30 of the photometric light receiving element 30
The portion corresponding to a is formed in the first curved surface portion 31a which is a convex surface with a large curvature, and this first curved surface portion 31a
The portions on both sides sandwiching the two are formed as second curved surface portions 31b and 31c which are convex surfaces with relatively small curvature.
This first curved surface portion 31a and second curved surface portion 31
b, 31c are for regulating the acceptance angle of light incident on this translucent member 31, and the curvature of the first curved surface portion 31a is the same as that of the second curved surface portions 31b, 31c.
The first curved surface portion 31a is larger than the curvature of the first curved surface portion 31a.
The light receiving angle of the second curved surface portions 31b and 31c is regulated to be much narrower than that of the second curved surface portions 31b and 31c. Condensing lenses 32 and 33 are disposed in front of the first curved surface portion 31a of the light-transmitting member 31. As shown in FIG.

In this way, the photometric light receiving element 30, the light-transmitting member 31, and the condensing lenses 32 and 33 constitute the photometric light receiving device 34.

In the camera equipped with the photometric light receiving device 34, before the shutter release, as shown in FIG.
6 has descended into the photographing optical path, and therefore, a portion of the subject light that has passed through the photographic lens 29 is directed upwards by the observation mirror 22 to form an image on the focusing screen 36. Light is pentaprism 3
7 and the viewfinder eyepiece lens 38 to reach the photographer's eye as observation light, and some of the other light passes through the observation mirror 22 and is reflected by the photometry reflector 26 to be used for photometry. It reaches the light receiving element 30 of the light receiving device 34.

The photometric light receiving device 34 is the photometric reflector 2
6, the reflected light from the photometric reflector 26 is directed toward the photometric light receiving device 34 as shown in FIG. That is, in FIG. 5, the curved surface portion 31a of the light-transmitting member 31 and the central light-receiving portion 30a of the photometry light-receiving element 30 reflect the specular reflection portion 26a of the photometry reflection plate 26 through the condenser lenses 32 and 33. The central part is oriented in the range shown by the chain line,
Further, the second curved surface portions 31b, 3 of the translucent member 31
1c, the light receiving sections 30b and 30c on both sides of the photometric light receiving element 30 are directed toward the diffuse reflecting section 26b of the photometric reflecting plate 26 excluding the specular reflecting section 26a within the range shown by the dotted line. Therefore, among the light transmitted through the photographic lens 29 and observation mirror 22 and reflected by the photometric reflector 26, the specular reflection portion 26a
The reflected light in the vicinity is directed to the condensing lenses 32 and 33,
incident on the first curved surface portion 31a of the translucent member 31,
The light is received by the central light receiving section 30a of the photometric light receiving element 30. Therefore, the photometric output from the light receiving section 30a is aligned with the optical axis of the photographing lens as shown by the solid line in FIG.
Partial photometry characteristic A showing a steep rise in the O _A part
becomes. In addition, the diffuse reflection part 2 of the photometric reflection plate 26
The reflected light from 6b enters the second curved surfaces 31b and 31c of the light-transmitting member 31, and is received by the light-receiving parts 30b and 30c on both sides of the photometric light-receiving element 30. Therefore, the photometric output obtained by adding the output of the light receiving section 30b and the output of the light receiving section 30c has a center-weighted average photometric characteristic B that increases slightly near the optical axis _OA , as shown by the dotted line in FIG. becomes.

In this way, a partial photometry output and a center-weighted average photometry output can be obtained at the same time from one photometry photoreceptor 30, so shooting can be performed in the partial photometry mode or the center-weighted average photometry mode depending on the photographer's intention. can be carried out freely.

In addition, in the above embodiment, the photometric reflector 2
Since the specular reflection part 26a is provided at the photometry reflector 26a, the partial photometry output shows a steep rise in a narrow range. What is necessary is to eliminate the specular reflection section 26a in . Further, in the above embodiment, the reflected light from the photometric reflector 26 is photometered,
This photometric value is memorized, and based on this memorized value, the above-mentioned observation mirror 2 is pressed by pressing the release button.
2 and the photometric reflector 26 are raised to open the photographing optical path to the shutter curtain 28 and the film 27, but the exposure time is controlled, but this is not limited to cameras of this type. The light receiving device 34 for photometry is installed directly facing the shutter curtain 28 and film 27 without using the photometry reflector 26, and the reflected light from the shutter curtain 28 and film 27 is applied to so-called direct photometry. may be received by the photometric light receiving element 30. In this case as well, the one-chip light receiving element 3
0 and the light-transmitting member 31, it becomes possible to obtain a partial photometric output and an average photometric output at the same time. The condensing lenses 32 and 33 are used to improve the light distribution characteristics of the first curved surface portion 31a of the light-transmitting member 31, and the curvature of the first curved surface portion 31a allows reflection for photometry. If the desired position range of the plate 26, shutter curtain 28, or film 27 can be directed sufficiently, there is no need to use the condensing lenses 32 and 33, but for example, if the light-transmitting member is made of plastic, etc. In this case, as shown in FIG.
A condensing lens part 41d is integrally installed with the member 41 in front of the member 41.
It is also possible to use a material formed by forming a . Further, the light receiving portions 3 on both sides of the curved surface portion 41a of the transparent member 41
Portions 41b and 41c that guide reflected light in the average photometry range to 0b and 30c may be formed as flat surfaces. Further, as shown in FIG. 8, a curved surface portion 51a that transmits light from the light receiving portion of the light-transmitting member 51 in a partial photometry range is provided.
may be made transparent, and the parts 51b and 51c on both sides that transmit the reflected light in the average photometry range may be mixed with a member that diffuses light, and the same parts may be formed on the matte surface.

In addition, the photometric light-receiving element 30 has light-receiving sections 30a, 30b, and 30c whose light-receiving surface is divided into three parts, and in addition, as shown in FIG.
It is also possible to use a photometry light-receiving element 60 having two light-receiving parts: a light-receiving part 60a for partial photometry formed in the center and a light-receiving part 60b for average photometry formed surrounding the light-receiving part 60a. .

As described above, according to the present invention, a one-chip photometric light-receiving element having a plurality of light-receiving parts and a light-transmitting member having a curved surface regulating the light-receiving angle to some of the light-receiving parts are combined. Since the outputs of multiple photometry modes are taken out from one photometry photoreceptor, there is no need to use complicated switching means as in the past, and the simple structure ensures reliable operation. It exhibits excellent effects such as being able to obtain any photometry mode.

[Brief explanation of the drawing]

FIG. 1 is a sectional view schematically showing an example of a conventional photometric light receiving device, FIG. 2 is a sectional view of a photometric light receiving device showing an embodiment of the present invention, and FIG.
FIG. 4 is an enlarged perspective view of the main part of the apparatus shown in FIG. 2, and FIG. 5 is a front view of the photometric reflector of the apparatus shown in FIG. 2. FIG. 6 is an enlarged plan view, a characteristic curve diagram showing the photometric characteristics of the device shown in FIG. 2, FIG. 7 is a perspective view showing another example of the translucent member, and FIG. FIG. 9 is a perspective view showing still another example of the optical member and a front view showing another example of the photometric light receiving element. 3, 29... Photographing lens, 9, 26... Reflector plate for photometry (reflection surface), 8, 10, 30, 60... Light receiving element for photometry, 30a, 30b, 30c, 60
a, 60b... Light receiving portion, 31, 41, 51... Transparent member, 31a, 41a, 51a... Curved surface portion regulating the light receiving angle.

Claims (1)

[Claims for Utility Model Registration] A light receiving element for photometry formed on one chip and having a first light receiving section in the center and a second light receiving section on the periphery thereof, and this light receiving element for photometry. a first light condensing section that is disposed in front of the element and has a light condensing effect of guiding a light flux that mainly corresponds to the center of the photographing screen out of the light flux that has passed through the photographing lens to the first light receiving section; It is provided at the outer edge of the light condensing part and has a different curvature from that of the first light condensing part, and the light flux corresponding to the entire photographing screen is directed to the second light condensing part.
A light-receiving device for photometry of a camera, comprising: a light-transmitting member having a second light condensing portion that guides the light to the light-receiving portion;