JPH05100186A - Image sensor - Google Patents

Abstract

PURPOSE:To provide a small-sized image sensor system which requires no large image forming lens. CONSTITUTION:The small-sized, inexpensive image sensor which requires no large-diameter image forming lens is constituted by arraying plural unit element systems S each consisting of three elements, i.e., a unit photodetecting element (d), a lens corresponding to the unit photodetecting element (d), and a pinhole P which is provided between unit photodetecting elements (d) and nearby the focal length (f) of the lens and has a much smaller aperture than the aperture diameter of the lens.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic image pickup tube and a CC.
The present invention relates to an image sensor system configured by arranging a plurality of light receiving elements in a linear shape or a plane shape such as a D or photodiode array.

[0002]

2. Description of the Related Art Image pickup devices used for optical information processing,
CCD (charge coupled device)
Image sensors such as e) and photodiode arrays are
As shown in FIG. 9, the image 13 of the subject 12 is displayed on the image sensor (image forming surface) 14 by utilizing the image formation of the lens 11.

[0003]

However, in such a conventional image pickup system, a single relatively large imaging lens is indispensable, and the existence of this imaging lens depends on the size of the image sensor system. It is a deciding factor and limits its miniaturization. The reason is that the distance between the lens and the light receiving element, which has a size necessary for image formation, is required in accordance with the size of the imaging lens.

On the other hand, as shown in FIG. 10, by using the lens 21 and the pinhole 22, only light having a specific spatial frequency passes (that is, in FIG. 10, only light A passes and light B is blocked. There is a spatial filter.

An object of the present invention is to provide a small image sensor system which does not require a large imaging lens by utilizing this method, that is, a method of interposing a pinhole between the lens and the light receiving element.

[0006]

According to the present invention, as a means for solving the above-mentioned problems of the conventional image sensor system, the image sensor of the first invention comprises a plurality of unit light receiving elements arranged. In the image sensor, a unit light receiving element, one lens corresponding to each unit light receiving element, and an aperture that is sufficiently smaller than the diameter of the aperture of the lens provided between the lens and the unit light receiving element and near the focal length of the lens. It is characterized in that a plurality of unit light-receiving elements, each of which is a set of three types of elements including the pinhole formed in the above, are arranged.

The image sensor of the second invention of the present application comprises one lens and a pinhole formed in an aperture sufficiently smaller than the diameter of the aperture of the lens provided near the focal length of the lens. It is characterized in that a plurality of unit space filter systems constituted by are provided on the light receiving element.

A plurality of lenses, a plurality of pinholes,
It is advantageous for ease of assembly and accurate imaging to have a plurality of single light receiving elements on the same surface. Further, it was effective that the optical axes of the single light receiving system were not parallel so that the size of the target space could be selected regardless of the size of the image sensor. Further, forming the lenses on the same substrate is effective in eliminating the trouble of adjusting the positions of the plurality of lenses. In addition, by providing the pinholes in contact with the front surface of the substrate on which the plurality of lenses are provided, the lenses and the pinholes can be aligned all at once, and there is an effect that they are resistant to impacts. Furthermore, providing an infrared cut filter between the unit light receiving element and the lens or on the lens surface was effective in removing ambient light.

[0009]

[Operation] In FIG. 10 showing the principle of the spatial filter, the smaller the pinhole size, the more effective the directivity becomes. However, it is not necessary to set it below the light diffraction limit. It is most effective to place the pinhole at the focal position of the lens.

However, as shown in FIG. 10, if a pinhole having an aperture sufficiently smaller than the lens diameter is provided near the focal point of the lens, the light propagating along the optical axis formed by the pinhole and the lens. A passes through the pinhole, but the light B that intersects the optical axis is blocked. Therefore, the intensity of only the light traveling from the vicinity of the optical axis to the lens can be detected. As a result, the scattered light intensity distribution in the space can be detected by arranging a plurality of optical systems as shown in FIG. 10 in parallel and directing the respective optical axes in arbitrary directions.

For example, in the image sensor system as shown in FIG. 8, in the optical system in which the lens l ₁ and the pinhole P ₁ are combined, the combination of the lens l ₂ and the pinhole P _{2 in} the region a ₁ of the image A is set. the combined area of a ₂ in the optical system due to the lens l in _n and the pinhole P _n combination optical system according to the respectively detected scattered light intensity in the region of a _n, it is found scattered light intensity of the space by combining them .. As a result, shape recognition and the like can be performed as in the conventional image sensor.

It is not always necessary for each light-receiving element to correspond one by one, and a plurality of small pixels such as CCDs may correspond thereto. Further, as shown in FIG. 8, one light receiving element d such as a CCD or an electronic picture tube capable of detecting the intensity distribution on the light receiving element surface may be provided for all optical systems.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

[0014]

[Embodiment 1] This embodiment specifically illustrates the invention of claim 1 of the present invention. In FIG. 1, the lens l
And a plurality of unit light receiving elements 5 each including a pinhole P having an opening sufficiently smaller than the diameter of the lens 1 provided at the focal position of the lens 1 and a unit light receiving element d are arranged to form an image sensor. is doing. The lens 1 may be a gradient index lens, a diffractive lens such as a micro Fresnel lens, in addition to a normal convex lens. The pinholes P may be formed by either a method of forming holes in a metal plate by etching or a method of mask-depositing a metal or the like on a glass plate. It should be noted that the lenses l _{1 to} l _n , the pinholes P _{1 to} P _n , and the light receiving elements d _{1 to} d _n can be configured on the same plane for easy assembly, and for accurate image formation. It is advantageous.

[0015]

[Embodiment 2] This embodiment explains a preferred embodiment of claim 4 of the present invention, and its outline is shown in FIG. The present embodiment is characterized in that the optical axes x _{1 to} x _n of the unit light receiving elements are not parallel. In other words, each lens l
The distance between the optical axis centers of No. 2 and the distance of the corresponding pinhole P do not match. With such an arrangement, the size of the target space can be selected regardless of the size of the image sensor.

[0016]

[Third Embodiment] This embodiment describes a preferred embodiment of the fifth aspect of the present invention, in which the lens 1 is formed on the same lens substrate LB as shown in FIG. The present embodiment has a feature that a plurality of lenses l _{1 to} l _n can be formed at once without the need for special position adjustment. As the substrate LB, a plastic plate such as a glass plate, an acrylic plate or a polycarbonate plate can be used. The lens 1 can be formed by a light irradiation molding method using an ultraviolet curable resin, an injection molding method, an ion diffusion method, or the like.

[0017]

[Embodiment 4] This embodiment explains a preferred embodiment of claim 6 of the present invention, and as shown in FIG.
It is formed in a structure in which pinholes P _{1 to} P _n are provided in contact with the back surface of a substrate provided with a plurality of lenses l _{1 to} l _n . In order to focus the light on the pinhole portion P, the thickness of the substrate LB is made substantially equal to the focal length f of the lens 1. The pinhole P may be formed by adhering a pinhole plate to the lens substrate LB, or may be provided by vapor deposition or the like. With such a configuration, the lens 1 and the pinhole P are collectively aligned, and besides, the lens 1 and the pinhole P are strong against impact.

[0018]

[Embodiment 5] This embodiment explains a preferred embodiment of claim 8 of the present invention. As shown in FIG. 5, a light receiving element d is provided with a lens 1 and a pinhole P. The structure is characterized by being fixedly integrated with the substrate. The distance between the light receiving element surface and the pinhole should be not larger than the focal length f of the lens.

[0019]

[Sixth Embodiment] This embodiment is intended to invent a preferred embodiment of claim 9 of the present invention. As shown in FIG. 6, an infrared cut layer R is provided to remove disturbance light. There are features. In this embodiment, an example in which a multilayer thin film R for infrared cutting is formed on a lens substrate LB provided with pinholes P by a vapor deposition method is illustrated.

[0020]

[Embodiment 7] This embodiment explains the second invention described in claim 2 of the present application. As shown in FIG. 7, one lens 1 and one lens l Focal length f
A plurality of unit spatial filter systems S, that is, S _{1 to} S _n , each including a pinhole having an aperture sufficiently smaller than the aperture diameter of a lens provided nearby, that is, S _{1 to} S _n are provided on one light receiving element d. Form an image sensor. In this way, a CCD that can detect the intensity distribution on the light receiving element surface,
Even if one light receiving element d such as an electronic image pickup tube is provided for all optical systems, the same effect as the first invention can be obtained.

[0021]

As described above, according to the present invention, a plurality of unit light receiving systems each including a light receiving element, a lens, and a pinhole are arranged, or a unit spatial filter including a lens and a pinhole is set. Multiple electron tube type image sensor and CC
By providing it on a light receiving element such as D, it is possible to provide a small and inexpensive image sensor system that does not require an expensive large-diameter imaging lens.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a first embodiment of an image sensor according to the present invention.

FIG. 2 is an explanatory diagram of a second embodiment of the present invention.

FIG. 3 is an explanatory diagram of Embodiment 3 of the present invention.

FIG. 4 is an explanatory diagram of Embodiment 4 of the present invention.

FIG. 5 is an explanatory diagram of Example 5 of the present invention.

FIG. 6 is an explanatory diagram of Example 6 of the present invention.

FIG. 7 is an explanatory diagram of Embodiment 7 of the present invention.

FIG. 8 is an explanatory diagram of an image forming operation of the image sensor according to the present invention.

FIG. 9 is an explanatory diagram of an image forming action of a conventional image sensor.

FIG. 10 is an explanatory diagram of the principle of a spatial filter.

[Explanation of symbols]

 d unit light receiving element f focal length l lens P pinhole S unit light receiving system

Claims (9)

[Claims] 1. An image sensor comprising a plurality of unit light receiving elements arrayed, wherein a unit light receiving element, one lens corresponding to each unit light receiving element, and the lens between the lens and the unit light receiving element. A plurality of unit light receiving elements, each of which is a set of three types of elements, that is, a pinhole formed in an aperture sufficiently smaller than the diameter of the aperture of the lens provided near the focal length of Image sensor. 2. A plurality of unit spatial filter systems each including one lens and a pinhole formed in an aperture that is provided near the focal length of the lens and is sufficiently smaller than the diameter of the aperture of the lens. An image sensor provided on a light receiving element. 3. The plurality of lenses, the plurality of pinholes,
The image sensor according to claim 1 or 2, wherein a plurality of unit light receiving elements are provided on the same surface. 4. The image sensor according to claim 1, wherein the directions of the optical axes of the respective unit light receiving element systems or the unit spatial filter systems are not coincident with each other. 5. The image sensor according to claim 1, wherein the lenses are formed on the same substrate. 6. The thickness of the substrate on which the lens is formed is
6. The image sensor according to claim 5, wherein the focus position of the light incident on the lens surface and the flat surface of the substrate on the side where the lens surface is not provided are matched with each other. .. 7. The image sensor according to claim 6, wherein a pinhole is provided in contact with a flat surface of the substrate on which the lens surface is not formed. 8. A substrate provided with a lens surface and a pinhole such that the distance between the light receiving element surface of the substrate provided with a plurality of unit light receiving elements and the pinhole is shorter than the focal length of the lens. The image sensor according to claim 7, wherein the image sensor is integrally formed and fixed. 9. The image sensor according to claim 1, further comprising an infrared cut filter provided between the unit light receiving element and the lens or on the lens surface.