JPS59210776A - Image sensor - Google Patents

Abstract

PURPOSE:To obtain a picture with high quality by using a substrate made of glass or the like through which light is transmitted as a convexed curved surface structure substrate and forming a transparent electrode layer, an amorphous silicon layer of p-i-n structure and a sensor mechanism comprising a back side electrode on the substrate. CONSTITUTION:The amorphous silicon layer 7 consists of a (p) layer 10, an (i) layer 11 and an (n) layer 12 and the thickness is, e.g., <=1mum. Lots of unit elements are provided in matrix longitudinally and laterally. The electrode 8 is led out at each element. Each element of the amorphous silicon can be separated and since the specific resistivity is large, when the thickness is 1mum and the interval between elements is 10mum, the series impedance is large and it is not especially necessary to separate each element. The boundary between the transparent electrode layer 6 and the amorphous silicon layer 7 becomes a photodetecting face 13. The light passes through a lens L, transmits through the glass substrate 5 and the transparent electrode 6 are reaches the photodetecting face 13. Since the photodetecting face 13 is matched to the curve of image, a picture without the out-of-focus even at the circumference of an image is obtained.

Description

[Detailed description of the invention] (a) Technical field This invention relates to a two-dimensional image sensor.

(B) Prior art and its problems Generally, as an 11il image input section of an image recognition device, etc., a lens system and an image pickup tube or a two-dimensional image sensor are connected at (t).
An imaging system is also used.

FIG. 4 is a diagram showing the optical system opening [A] for explaining the conventional imaging system.

An image of an object T is formed on an image sensor 1 by a lens LVc. The light receiving plane of a conventional image sensor is 3.1 plane. When an image of an object is formed using a flat image sensor, the image quality deteriorates at the fixed edges of the screen.

The reason for this is thought to be as follows.

Strictly speaking, the true image forming surface through the lens L is concave, k,
This means that it will not be flat.

The true image forming surface S is a concave 1-1 that touches the light-receiving surface Q at the center.
・Become alone.

The imaging surface S and the flat light-receiving surface Q shift back and forth toward the periphery. At the periphery of this useless image, the image on the light-receiving surface becomes blurred.

To avoid this, conventionally, a combination lens etc. was used,
A method was used to correct the field curvature and prevent the image quality from deteriorating.

However, conventional imaging systems use combination lenses/
It had the disadvantages of being bulky, heavy, and large.

It is desirable for imaging devices to become more compact and compact.

In promoting miniaturization, heavy and large coarse-grained lenses are unsuitable. I would like to configure an imaging system using a simple lens system without using a combination of lenses. In this way, a light 1i, small-sized image input device can be manufactured.

Determine how far the true imaging plane S deviates from the plane Q. FIG. 5 is a schematic diagram of the optical system for explaining the curvature of field in the tun lens.

The optical axis of lens L is assumed to be the X axis. Let O be the imaging point of the object T on the optical axis. Let Q be the plane passing through 0 and perpendicular to the X axis. And then
An image S with the y-axis above is shown by a broken line.

Since the imaging surface 5 (is rotationally symmetrical with respect to the X-axis), if the deviation ΔX between the imaging surface and the plane Q in the y-axis direction is known, the imaging surface S can be determined.

Assume that object 14 is at infinity. focal length of the lens f2
82 seats, (assuming that there are 56 seats in one radius. θ is the angle of view,
y is the distance from the plane 1ilI+, and ΔX is the deviation of the imaging river S from the plane Q.

Table 1 (1 angle of view θ, deviation Δx, distance from x-axis UP, y
・This is a table showing the calculation results of field curvature corresponding to k.
.

Table 1 Calculation results of field curvature (g - = 28 tsm, D = 56 Mi, object at infinity) As shown above, at a field angle of 19.24°, the imaging position is on the plane Q
The lens is shifted about 2 mm away from the lens. In this way, field curvature occurs.

In this case, the imaging surface S approximates a spherical surface with a radius of 20M, but is not a strict spherical surface.

In addition, although the cross-sectional shape of the imaging surface S is approximated to a parabola by fl, it is not strictly a parabola.

In general, the image surface () curvature is the curvature of the surface after 1]fi of the lens, 1ii! 4714: It varies depending on the shape of the object and the position of the object.

The image plane ζ411 is an aberration in geometric optics and has been known for a long time.

Usually, a flat image plane is omitted by combining two lenses that satisfy the Happenvall (Petzval) condition. However, when lenses are combined, it becomes large and heavy.

However, the curvature of field can be calculated using a certain formula by determining convenient parameters such as lens curvature and refractive index according to Perapard's theorem. The formula underlying this calculation is well known.

(1) Structure of the present invention Conventionally, a flat image was obtained by using a c-h, rit combination lens.

The present invention uses a full lens and a light-receiving section that matches the field curvature. 1j(
Determine j by I (V?). Using a concave light receiving part that matches the curvature of field (even if it is on the optical axis, it is far from the optical axis.
1 distance f1. Even in the fWi, range (.), it is possible to equally form a blurred image on the light receiving section.

4. Komei's image sensor has (1) a substrate with a concave curved structure close to the field curvature, and (2)
It consists of a sensor mechanism provided on a substrate with a concave curved surface structure, and (3) a medium 1/2-lens lens or a small number of combination lenses that form an image of an object onto the sensor mechanism.

FIG. 1 is a schematic diagram of an optical system structure of an image sensor according to the present invention.

The lens holder is not a combination of lenses, but a single lens. It consists of an image sensor 1 concave curved structure substrate 1 and a sensor device 4% 2 formed on this -42.

The sensor mechanism 2 converts the actual intensity into an electrical signal. The concave curved surface of the substrate 1 is made to match, for example, the field curvature of a plane object T placed at infinity due to a single lens L. If it is difficult to match exactly, then as a part of an approximate concave spherical surface or a part of an approximate curved modified surface,
A concave curved structure substrate 1 is manufactured; litho is performed.

14, amorphous silicon, crystalline silicon, crystal compound ゛I'-conductor (GaA
s, GaAl1? AsI nGaA//p, etc.) can be used.

The second section shows an example in which an amorphous silicon layer of p + n I'fkb is used as a sensor device t1'δ and is formed on a glass substrate. FIG. 3 is a partially enlarged sectional view of the amorphous silicon sensor device (1).

In the case shown in FIG. 1, a sensor device (1'k) is provided on the concave side of a concavely curved substrate 1.The sensor device (1'k) is provided on the convex side of a transparent substrate such as glass. +I'6 has been completely formed.

This image sensor has a glass substrate 5 having a concave curved structure.
-, a transparent electrode 6 and an amorphous silicon layer 7 with a ρ-1-n structure are formed, and electrodes #t and 8 are formed on each element separated by a pair of 1·b. . As described above, the concave curved glass substrate 5 has a concave curve that approximates the im-plane curvature.

The amorphous silicon layer 7 includes a p layer 10 and an i layer 11.0.
It consists of a layer 12, and its thickness is, for example, 1 μl or less. The amorphous silicon layer 7 is a collection of a large number of intermediate elements. Unit elements are arranged in a matrix in both directions. Electricity, Corps EI (・Ma is drawn out for each element. 6 elements of amorphous silicon rQ, j, minutes before, may be done,
If the element spacing is 10μ7n or more, it is not necessary. Amorphous silicon has a large resistivity, so if the thickness is 1 μrn and the distance between elements is 10/l + n,
The series impedance is increased and there is no need to separate old elements.

The boundary between the transparent electrode layer 6 and the amorphous silicon layer 7 becomes the light receiving surface 13.

In other words, it passes through the lens L, the glass substrate 5, and the transparent electrode layer 6.
Transmit 1. Then, the light reaches the light receiving surface 13. Since the light-receiving surface 13 is adapted to coincide with the image plane ζ/1,000 degrees, it is possible to produce a plane image without blur even in the peripheral area of the image.

(1) Effect: When a single lens is used in an image input device that images an object, curvature of field is always caused.

In the present invention ii, the number of lenses is increased, and the image plane is 7! We solved this difficult problem by using a concave sensor device f'i7j <1 that matches the image plane 7 and the ψ-curve, instead of 1 since we modify the ψ-curve.

Is the sensor concave? Since the light plane is tilted, -C at the periphery of the image is also focused on the positive plane, so that blurring occurs in the +η part of the image. You can rl high quality images.

Since there is only one lens per lens, it can be made smaller with a light claw.

This image sensor is widely used in both image processing devices.
9 human power i/, (closed 11) can be 1, Senza i 1' i ro part 1 ・ Since it is curved, 1 amorphous '1', ij' (Nori: '1)) This is the easiest material to make. However, in addition to this, there are also sensors that open the p-1-n junction of semi-crystalline (silicon, chemical compound (I'), photoconductor sensors) and (7)
available.

[Brief explanation of the drawing]

a'lJt t: Melij Mio 1st 1 Optical system configuration of the image sensor Figure 2 shows the sensor mechanism and 1. te, -i -
Optical system IV7i diagram showing an example using n f+'H amorphous silicon. FIG. 3 is a partially enlarged cross-sectional view of the sensor device 114. Figure 4 i-:t A case diagram of a lens system that explains the field curvature of 11゛ when using a single lens. Parameters for a. Silicon layer 8...
・Back electrode 10-1 layer 11...--1 layer 12...-1 layer L--Lens T-Object Q Light-receiving section S-True imaging surface (image surface 3 (Tokyo) Inventor: Kimi Ono Three major players: Akira Oka, Yukazu 1) Yutaka

Claims (2)

[Claims] (1) An image sensor comprising a concave curved surface (11t+: J'+"C substrate 1) and a sensor mechanism 2 provided on the concave curved structure substrate 1. (2) A light-transmissive substrate 5 such as glass is used as the concave curved surface +1'η substrate, and on the substrate 5, a transparent sales layer 6,
An image sensor according to claim 1, which comprises a sensor mechanism constituted by an amorphous silicon layer 7 having an o-1-n structure and a back electrode 8.