JPH04305608A - Range finder mechanism for camera - Google Patents

Abstract

PURPOSE:To prevent range-finding accuracy from lowering by preventing base length from becoming short in the case of providing an active system range finder mechanism in a small-sized camera. CONSTITUTION:A light projecting part 401 and a light receiving part 501 are arranged in the lateral direction of a camera main body 101. A mirror 512 which is positioned behind a light projecting(receiving) lens 511 and has a reflection surface (a) for bending the axis of an optical path to a direction in parallel with a base is provided in at least either of the light projecting part 401 and the light receiving part 501, and a light projecting(receiving) element 513 is arranged on the side of the internal mechanism such as a cartridge chamber 102.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring mechanism for a camera, and more particularly to an active distance measuring mechanism.

0002

2. Description of the Related Art Conventionally, active distance measuring mechanisms have been relatively frequently used as autofocus mechanisms in lens shutter cameras. In general, this distance measuring mechanism includes a light projecting section consisting of a light projecting element and a light projecting lens for emitting light toward a subject, and a light receiving section consisting of a light receiving lens and a light receiving element that receives light reflected from the subject. are attached to a common base, constructed as a single unit, and incorporated into the camera body.

By the way, in the field of such lens shutter cameras, there has been a strong demand for smaller and thinner cameras. In order to meet this demand, it is necessary to downsize and consolidate the internal mechanism, so it is naturally desired that the distance measuring unit described above be downsized as well. Here, in order to downsize the distance measuring unit, it is necessary to shorten the focal length of the light emitting/receiving lens and the base line length, that is, the distance between the light projecting section and the light receiving section.

On the other hand, in the past, such lens-shutter cameras did not require very high range-finding performance, but as the technology has become more sophisticated in recent years, even higher accuracy has been required. It has become. In this type of distance measuring mechanism, the longer the base line length, the greater the movement of the image on the light receiving element, and the better the distance measuring accuracy. Therefore, in order to improve the distance measurement accuracy, it is sufficient to increase the base line length. However, if the baseline length is made longer, the unit becomes larger, which goes against the miniaturization of cameras. It would be desirable if it were possible to downsize the .

However, it is difficult to miniaturize the camera by arranging the internal mechanisms in a concentrated manner without downsizing the distance measuring mechanism. The reason for this will be explained using FIGS. 1 and 2. FIG. 1 shows a front view of a conventional general lens shutter camera, and FIG. 2 shows an enlarged cross-sectional view thereof. In the figure, 1 is a camera body, 2 is a zoom lens barrel, 3 is a finder, and 4 and 5 are a light projecting section and a light receiving section of a distance measuring mechanism. The light projecting section 4 and the light receiving section 5 are arranged in the vertical direction of the camera body 1. As shown in FIG. 2, the camera main body 1 is composed of a body 11 and a front cover 12, and a back cover 62 having a film pressure bonding plate 61 is attached to the back thereof. A spool chamber 13, a cartridge chamber 14, and a battery chamber 15 are formed within the main body 1, and a flash condenser 16 is attached. The light projecting unit 4 of the distance measuring mechanism is constructed by attaching a light projecting element 44 held by an element holder 43 and a light projecting lens 41 to a base 42 disposed diagonally in front of the spool chamber 13. The base 42 is a member formed vertically in order to configure the light projecting section 4 and the light receiving section 5 as one unit, and the light receiving section 5 is
Although not shown, the lower portion of the base 42 is configured similarly to a light projecting section, including a light receiving lens and a light receiving element held by an element holder.

If, for example, the distance between the spool chamber 13 and the cartridge chamber 14 is to be shortened in order to downsize the camera with this configuration, keeping the distance measuring mechanisms 4 and 5 at the positions shown in FIG. This is difficult because the outer wall of the spool chamber 13 comes into contact with the distance measuring mechanisms 4 and 5. On the other hand, it is difficult to move the light projecting section and the light receiving sections 4, 5 toward the center of the camera because the distance measuring mechanisms 4, 5 come into contact with the lens barrel 2. To avoid these problems, the distance measuring mechanism 4,
5 must be moved toward the subject (to the front) and placed in front of the spool chamber 13, so a large protrusion is formed on the camera. In order to avoid forming such a protrusion on the camera, the distance between the light emitting and receiving parts should be adjusted so that the light emitting part 4 is located above the spool chamber 13 and the light receiving part 5 is located below the spool chamber 13. Since it has to be expanded, the camera increases in size in the height direction, which is contrary to the desired miniaturization of the camera. In addition, in FIG. 1, the light emitting section 4 and the light receiving section 5 are arranged above and below the camera, but if they are arranged side by side in the left and right direction, the distance between the spool chamber 13 and the cartridge chamber 14 can be reduced. and the baseline length becomes shorter,
Distance accuracy decreases.

Therefore, the technical problem to be solved by the present invention is to provide a distance measurement mechanism that can ensure a certain distance measurement accuracy even if the camera is miniaturized.

[0008]

[Means for Solving the Problems, Actions and Effects] In order to solve the above-mentioned technical problems, the distance measuring mechanism of the camera according to the present invention is constructed as follows.

That is, the distance measuring mechanism is such that a base line connecting the light emitting part and the light receiving part is arranged along the lateral direction of the camera body, and at least one of the light emitting part and the light receiving part is located at a predetermined position in the camera body. The light emitting (receiving) element includes a reflecting means disposed obliquely in front of the internal mechanism and having a reflecting surface positioned behind the emitting (receiving) light lens to bend the optical path axis substantially parallel to the base line; is located on the side of its internal mechanism. As this reflecting means, for example, a mirror can be used.

In this configuration, for example, if a mirror is provided as a reflection means in the light receiving section, the light emitted from the light projecting section and reflected by the object is transmitted through the light receiving lens, and is further reflected by the reflecting surface of the mirror parallel to the base line. The light is bent in this direction and enters a light receiving element placed on the side of the internal mechanism. By providing a mirror that bends the optical path in this way, even if the light receiving section is installed diagonally in front of the internal mechanism, it is possible to avoid the light receiving element and its internal mechanism coming into contact with each other. They can be placed close together, and the camera can be made smaller without shortening the baseline length.

[0011] Furthermore, in the above configuration, the reflecting means is
Preferably, the prism is formed by integrally forming a reflecting surface that reflects light along the base line and a light projecting (receiving) lens. With this configuration, unlike the case where the reflecting means is composed of a mirror and is separate from the light emitting (receiving) lens, there is no possibility of installation errors occurring between the light emitting (receiving) lens and the reflecting surface. Since there is no interference, positioning of the light emitting (receiving) element itself becomes easy, and workability during installation is improved.

Further, in the above configuration, it is preferable that the reflective surface of the mirror or prism is arranged along the outer wall of the film chamber such as the cartridge chamber or the spool chamber. With this configuration, when the distance between the cartridge chamber and the spool chamber is narrowed in order to make the camera smaller in the horizontal direction, it is possible to prevent the light emitting (receiving) element from hitting the outer wall of the film chamber without shortening the baseline length. Since it is possible to prevent this from occurring, the camera can be effectively miniaturized while maintaining a certain distance measurement accuracy.

[0013]

[Example] Below, the first embodiment of the present invention shown in FIGS. 3 and 4 will be described.
A camera equipped with a distance measuring mechanism according to an embodiment will be described in detail. FIG. 3 is a front view of this camera, and FIG. 4 is an enlarged cross-sectional view thereof. In the figure, 101 is the camera body, 20
1 is a zoom lens barrel, 301 is a finder, 401 is a light emitting section of a distance measuring mechanism, 501 is a light receiving section of the distance measuring mechanism, 701 is a photometric mechanism, and 801 is a flash. As shown,
The light projecting section 401 and the light receiving section 501 are arranged in the lateral direction of the camera body 101.

As shown in FIG. 4, the camera body 111 divides the interior of the camera body 101 into a cartridge chamber 1.
02, a spool chamber 103 and a battery chamber 104 are formed. The finder 301 includes objective lenses 313 and 314
, an image erecting optical system 312 such as a Porro prism, and an eyepiece 315 are held in a finder base 311 to form a unit, and the finder base 311 is attached to the camera body 111 .

The light projecting section 401 of the distance measuring mechanism includes a light projecting element 41
3, an element holder 414 and a light projection lens 412. The light projecting lens 412 is fixed to a distance measuring base 411 that holds both the light projecting and receiving parts. Light projecting element 4
13 is attached to the light emitting element holder 414, positioned with respect to the optical axis of the light emitting lens 412, and then mounted on the distance measuring base 4.
It is fixed at 11. The light receiving unit 501 includes a light receiving lens 5
11, a mirror 512, a light receiving element 513, and a light receiving element holder 514, and is arranged diagonally in front of the cartridge chamber 102. A distance measuring base includes a light receiving lens 511 and a mirror 512 having a reflective surface a inclined at 45 degrees with respect to the optical axis of the light incident on the lens in order to bend the light transmitted through the light receiving lens 511 along the base line. 4
It is fixed at 11. Mirror 512 is patrone room 1
It is arranged along the outer wall 102a of 02. The light-receiving element 513 is mounted on a light-receiving element holder 514, positioned with respect to the optical axis of the light-receiving lens 511, and then fixed to the ranging base 411. In this way, the light emitting unit 401 and the light receiving unit 501 are connected to each other by the distance measuring base 411.
The distance measuring base 411 is attached to the camera body 111. Further, the photometry mechanism 701 is configured integrally with the distance measurement mechanism by attaching a photometry lens 711 and a photometry element 712 to the base 411 of the distance measurement mechanism.

In the distance measuring mechanism configured as described above, the mirror 512 is arranged at an angle of 45 degrees along the outer wall 102a of the patrone chamber 102 to bend the optical path axis of the light receiving section 501, and the light receiving element 513 is placed directly behind the light receiving lens. Even if the distance between the spool chamber 103 and the cartridge chamber 102 is narrowed, the light-receiving element 513 and the outer wall 102a of the cartridge chamber 102 are prevented from hitting each other, and the baseline length is kept wide. be able to. Therefore, it is possible to both prevent a decrease in distance measurement accuracy and downsize the camera.

Next, the distance measuring mechanism according to the second embodiment shown in FIG. 5 will be explained. The light projecting unit 401 and the photometry mechanism 701 of this distance measuring mechanism have the same configuration as in the first embodiment, so a description thereof will be omitted (the same parts are given the same reference numerals as in the first embodiment). Light receiving unit 50 configuring the distance measuring mechanism
1' has a prism 522 which integrally constitutes a light receiving lens section 521 and a reflecting surface a as a reflecting means,
The light receiving element 513 and the light receiving element holder 514 are constructed in the same manner as in the first embodiment.

[0018] With this configuration, not only is it possible to prevent a decrease in distance measurement accuracy and downsize the camera, but also the workability during assembly is improved compared to the mechanism of the first embodiment. In other words,
In the mechanism of the first embodiment, the mirror 512 is connected to the distance measuring base 41.
1, there is a risk that the position may shift relative to the light receiving lens 511 or the mounting angle may be incorrect.
Therefore, the amount of adjustment required for positioning the light receiving element 513 may increase, but with this configuration, it is not necessary to align the light receiving lens section 521 and the reflective surface a, so the adjustment amount necessary for positioning the light receiving element 513 is The amount of necessary adjustment can be reduced. Additionally, the number of parts can be reduced.

Note that the present invention is not limited to these embodiments, but can be implemented in various other embodiments. For example, in the above embodiment, the mirror 512 or prism 522 as the reflecting means is used as the light receiving section 501, 522.
01', but it may be provided only in the light projecting section 401 or in both the light projecting section 401 and the light receiving section 501. Furthermore, although each of the above embodiments is an example in which the light receiving element 513 is shifted toward the light projecting section 401, it is preferable that the internal mechanism such as the cartridge chamber 102 is located between the light projecting section 401 and the light receiving section 501. In this case, the light receiving (emitting) element 503 (
413) may be shifted in the opposite direction to the light emitting (receiving) portion 401 (501).

[Brief explanation of drawings]

FIG. 1 is a front view of a camera equipped with a distance measuring mechanism according to a conventional example.

FIG. 2 is an enlarged cross-sectional view of the camera shown in FIG. 1;

FIG. 3 is a front view of a camera equipped with a distance measuring mechanism according to a first embodiment of the present invention.

4 is an enlarged cross-sectional view of the camera shown in FIG. 3. FIG.

FIG. 5 is an enlarged cross-sectional view of a distance measuring mechanism according to a second embodiment.

[Explanation of symbols]

101 Camera body 102 Patrone room 102a External wall 103 Spool room 104 Battery compartment 111 Camera body 201 Zoom lens barrel 301 Finder 311 Finder base 312 Porro Prism 313, 314 Objective lens 315 Eyepiece 401 Light projection part 411 Ranging base 412 Flood lens 413 Light projecting element 414 Light emitter holder 501, 501' Light receiving part 511 Light receiving lens 512 Mirror 513 Photo receiving element 514 Photodetector holder 521 Light receiving lens section 522 Prism 701 Photometering mechanism 711 Photometric lens 712 Photometric element 801 Flash

Claims (4)

[Claims] Claim 1: A light projecting lens (412) and a light projecting element (
a light emitting unit (401) having a light receiving lens (413) and a light receiving lens (5
11, 521) and a light receiving section (501, 501') having a light receiving element (513), and the baseline connecting the light emitting section (401) and the light receiving section (501, 501') is the camera body (101, 521). ), the light projecting section (401) and the light receiving section (501, 501
At least one of the lenses (501, 501') of
21) having a reflecting surface (a) that bends the optical path axis substantially parallel to the base line (512, 52);
2), the element (513) of which is connected to the internal mechanism (102).
) A camera distance measuring mechanism characterized by being placed on the side of the camera. 2. Reflection means (
5. The distance measuring mechanism for a camera according to claim 1, wherein 512) is a mirror. 3. A distance measuring mechanism for a camera according to claim 1, wherein the reflecting means (522) is a prism formed by integrally forming the lens (521) and the reflecting surface (a). . 4. The reflective surface (a) is located in the film chamber (1).
4. The distance measuring mechanism for a camera according to claim 1, wherein the distance measuring mechanism is disposed along an outer wall (102a) of the camera.