JPH0727105B2 - Light-receiving element for camera distance measurement - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a distance-measuring light-receiving element of a camera used for detecting a distance to a subject by receiving reflected light from the subject.

[Description of Prior Art] In the so-called light-projection-type distance measurement in which a subject is projected and the reflected light is received to detect the distance to the subject, a light receiving configuration shown in FIG. 3 is known. In FIG. 3, 1 and 2 are light receiving elements, and 3 and 4 are condenser lenses. Light receiving element 1
And 2 are arranged vertically, and light-receiving images 5 and 6 by reflected light from the subject are given to these light-receiving surfaces via the corresponding condenser lenses 3 and 4. The light receiving surface of the light receiving element 1 is provided with a sawtooth-shaped light shielding filter 7,
Nothing is provided on the light receiving surface of the other light receiving element 2.
With such a configuration, when the incident angle of the reflected light changes according to the distance to the subject, the light-receiving images 5 and 6 are displaced in the directions AB in the figure. If the brightness of the reflected light is always constant, the light receiving element 1 provided with the light shielding filter 7 provides the displacement information of the light receiving image 5, that is, the distance information to the subject. However, since the brightness of the reflected light changes depending on the degree of reflection of the subject, the brightness of the external environment, etc., the output of the light receiving element 1 is affected by the change in the brightness of the reflected light. Therefore, a method is adopted in which the light receiving element 2 detects the brightness of the reflected light and cancels the change in the brightness of the reflected light using the detected light to extract the distance information to the subject.

According to such a light receiving structure, two light receiving elements and two
Two condensing lenses are required, and there are problems such as parallax caused by the difference in the positions of the two light receiving elements, and manufacturing variations between the light receiving elements and between the condensing lenses.
If the detection of the distance information to the subject and the detection of the brightness of the reflected light can be performed by a single light receiving element, not only the above problems can be solved but also the space of the light receiving portion can be reduced and It is possible to reduce the score.

[Object of the Invention] The present invention has been made based on the above viewpoint, and an object of the present invention is to provide a distance-measuring light-receiving element for a camera capable of detecting distance information to a subject and brightness of reflected light. To provide.

[Means for Achieving the Object] In the present invention, a first photoreceptor having a plurality of light-receiving surfaces arranged in a comb-teeth shape, each light-receiving surface having a strip shape with a uniform width, and a comb-teeth shape A plurality of light receiving surfaces arranged in a line, each light receiving surface having an elongated tapered shape, and the first and second light receiving bodies are electrically independent of each other,
The above object is achieved by a distance-measuring light-receiving element of a camera in which the light-receiving surfaces of the respective light-receiving bodies are combined in an interleaved pattern.

That is, when a light-receiving image of reflected light from a subject is given, the first light-receiving body receives the light-receiving image on the light-receiving surface of a uniform width to give an output according to the brightness of the reflected light,
When the second light receiving body receives the light receiving image on the tapered light receiving surface, an output including displacement information of the light receiving image, that is, information on the distance to the object is given.

[Embodiment of the Invention] FIG. 1 is a block diagram showing an embodiment of the present invention.

In the figure, 10 is a light receiving element for distance measurement, which is provided with a first light receiving body 11 and a second light receiving body 12 which are electrically independent from each other. The first light receiving body 11 has a base portion 13 and a plurality of light receiving surfaces 14 arranged in a comb tooth shape. Each light-receiving surface 14 has a uniform width
The strips of W ₁ are arranged in parallel with each other with a gap W ₂ therebetween, and one end thereof is integrated with the base portion 13. The lengths of the respective light receiving surfaces 14 are the same, as is clear from the figure. The second light receiving body 12 has a base portion 15 and a plurality of light receiving surfaces 16 arranged in a comb tooth shape.
Each light-receiving surface 16 has an elongated tapered shape having a uniform width portion 16a having the same axis as the uniform width W ₁ of the light-receiving surface 14 and a wedge-shaped portion 16b that is tapered with the uniform width portion 16a as the maximum width, and has a uniform width component. 1
6a are arranged in parallel at the same spacing as the spacing W ₂ of the light receiving surface 14,
The end on the side of the uniform width portion 16a is integrated with the base portion 15. The tip of the wedge-shaped portion 16b is configured to converge on the center line of the uniform width portion 16a, and the uniform width portion 16a of each light receiving surface 16 is formed.
The dimensions and shape of the wedge-shaped portion 16b are the same, as is apparent from the drawing. The length of the light receiving surface 16 is shorter than the length of the light receiving surface 14, and the width W ₁ is selected to be smaller than the interval W ₂ .

The first light receiving body 11 and the second light receiving body 12 having such a configuration are combined in a comb shape in which the light receiving surface 14 and the light receiving surface 16 are alternately arranged, and with respect to the displacement direction CD of the received light image. Section
In P ₁ , only the light-receiving surface 14 of the first light-receiving body 11 exists, and in the intermediate section P ₂ , the wedge-shaped portion of the second light-receiving body 12 that changes in area with the light-receiving surface 14 of the first light-receiving body 11 16b and the light receiving surface 14 of the first photoreceptor 11 and the uniform width portion 16a of the second photoreceptor 12 are present in the section P ₃ . The size of the light receiving element 10 for distance measurement is about 2.5 x 2.5 mm,
The width W ₁ is selected to be 40 μm and the interval W ₂ is selected to be about 50 μm.

FIG. 2 is an operation explanatory diagram of the configuration of FIG. 1, and shows the photocurrent I ₁₁ of the first photoconductor ₁₁ and the photocurrent I _{12 of} the second photoconductor ₁₂ with respect to the displacement of the received light image. 1st with reference to FIG. 2 below
The operation of the configuration shown in the figure will be described.

The light receiving surface 14 of the first light receiving body 11 and the light receiving surface 16 of the second light receiving body 12 combined in a comb shape are provided with a light receiving image by reflected light from a subject through a condenser lens (not shown). The received light image is displaced in the CD direction according to the change in the incident angle of the reflected light according to the distance to the subject. Since the light-receiving surface 14 of the first light-receiving body 11 has a uniform width W ₁ , the photocurrent according to the brightness of the light-receiving image is independent of the displacement of the light-receiving image.
Outputs I ₁₁ . Therefore, if the brightness of the received image, that is, the brightness of the reflected light changes, I ₁₁ shown in FIG. 2 changes. Second
The light receiving body 12 has no light receiving surface in the section P ₁ , has a wedge-shaped portion 16b of the light receiving surface 16 in the intermediate section P _{2, and} has a light receiving surface 16 in the section P _3.
Since there is a uniform width portion 16a, the photocurrent I ₁₂ changes according to the displacement of the received image. That is, as shown in FIG. 2, when the received light image exists in the section P ₁ , the second
In the photocurrent I ₁₂ is substantially zero of the photoreceptor 12, the light receiving image intermediate section P ₂
, The photocurrent I ₁₂ is increased as the received light image is displaced from the tip of the wedge-shaped portion 16b toward the uniform width portion 16a.
Is increased and the received light image exists in the section P ₃ , the photocurrent I ₁₂ of the second photoconductor ₁₂ becomes equal to the photocurrent I ₁₁ of the first photoconductor ₁₁ . The photocurrent I ₁₂ is curved at the boundary between the sections P ₁ -P ₂ and the sections P ₂ -P ₃ because the received light image has a width.

Photocurrent I ₁₁ of the first photoreceptor 12 and photocurrent I ₁₁ of the second photoreceptor 12
By taking out ₁₂ and and obtaining the ratio I ₁₂ / I ₁₁ between them, the change in brightness can be canceled, and the displacement of the received light image, that is, the distance information to the object can be obtained.

EFFECTS OF THE INVENTION As described above, according to the present invention, the first light receiving body having the band-shaped light receiving surface of uniform width and the second light receiving body having the elongated tapered light receiving surface are respectively provided. Since the light-receiving surfaces are combined in an interleaved arrangement, the first light-receiver gives an output according to the brightness of the reflected light, and the second light-receiver gives the displacement information of the light-receiving image, that is, the distance information to the object. It is possible to provide a light-receiving element for distance measurement of a camera that gives an output including, and there is no need to consider the parallax due to the use of two light-receiving elements and the manufacturing variations of elements and lenses.
Since the light receiving element and the condenser lens are single, the space of the light receiving portion can be reduced and the number of parts can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG.
FIG. 3 is a diagram for explaining the operation of the configuration shown in FIG. 3, and FIG. 3 is a diagram showing a conventional light receiving configuration. 10 ...... Distance measuring light receiver, 11 ...... First light receiving member 12 ...... Second light receiving member, 14,16 ・ ・ ・ Light receiving surface 16a …… Uniform width part, 16b …… Wedge shape part

Claims (1)

[Claims] 1. A first photoreceptor having a plurality of light-receiving surfaces arranged in a comb tooth shape, each light-receiving surface having a strip shape with a uniform width, and a plurality of light-receiving surfaces arranged in a comb tooth shape. And a second light-receiving body each having a light-receiving surface having an elongated tapered shape, wherein the first and second light-receiving bodies are electrically independent of each other, and the light-receiving surfaces of the respective light-receiving bodies are arranged alternately. A photodetector for distance measurement of a camera, characterized in that it is combined in a blind shape.