JPH08182006A - Single ccd solid-state color image pickup device - Google Patents

Abstract

PURPOSE: To obtain a solid-state image pickup device with high light utilizing efficiency and high sensitivity by adopting a single CCD and a prism system for the color separation system. CONSTITUTION: A light stopped in a stripe by a micro condenser lens 100 is made incident on a prism main body 200. Plural prism sections are formed to a prism main body 200 and each color light dispersed by each prism section is led to each pixel of a single solid-state image pickup element 300 arranged opposite thereto.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color solid-state image pickup device, and more particularly, it can improve the light-collecting sensitivity.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional color solid-state image pickup device. In FIG. 5A, incident light is separated into three primary colors of RGB by a dichroic prism 10 and solid-state image pickup devices (R-CCD, G-CCD, B) corresponding to the respective primary colors.
-CCD) is provided. This type of color solid-state imaging device is called a three-plate type. This color solid-state image pickup device requires three image pickup elements and requires a technique for attaching the solid-state image pickup element to the prism with high accuracy, so that it is expensive and large in size.

On the other hand, there is a single plate type, but an image pickup device thereof is shown in FIG. This solid-state image sensor has RGB color filters arranged in stripes as color pixels in spatial pixels. Since this color solid-state imaging device is a single plate, it is inexpensive and can be miniaturized. However, since it is a type in which color separation is performed by a color filter, incident light of a wavelength other than a desired color is absorbed by the color filter in terms of a pixel unit and is not effectively used. In particular, the separation by the primary color filter has a problem that only one color of RGB passes through and the sensitivity is insufficient. In order to solve this, the pixel area must be increased. However, if the pixel area is increased, the problem of resolution and the size of the device increase accordingly.

[0004]

As described above, in the conventional color solid-state image pickup device, the three-plate type has a large number of elements and requires mechanical assembling precision, so that it is expensive and large in size. Further, the single plate type has a problem that the sensitivity is low or the resolution is sacrificed because the absorption rate of the incident light by the filter is large. Therefore, it is an object of the present invention to provide a single-plate color solid-state image pickup device which uses a prism type color separation system and has high light utilization efficiency and high sensitivity.

[0005]

According to the present invention, a plurality of prism parts are formed in a prism body, and each color light corresponding to a plurality of pixels separated by each prism part corresponds to a single plate type solid-state image pickup device. It is configured to be led to each of the pixels.

[0006]

According to the above means, there is no loss of incident light, the light utilization efficiency is good, and the imaging sensitivity is improved. Further, since it is a single plate type, it is smaller and cheaper than the multi-plate type.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention. Figure 1 (A)
In the above, reference numeral 100 denotes a micro condensing lens having a plurality of lenses. Below the micro condensing lens 100, an external planar prism main body 200 having a prism portion in a stripe shape is arranged. The light that has entered through the micro condenser lens 100 is separated by the prism portion of the prism body 200, and the separated color lights are applied to the image forming surface of the solid-state image sensor 300. In FIG. 1B, a part of the prism main body 200 is taken out and shown. One surface of the prism body 200 has a sawtooth cross section. The inclination is, for example, an inclined surface of 45 degrees.

In each lens portion of the micro condensing lens 100, assuming that the focal length of the front-side convex lens is a and the focal length of the back-side convex lens is b, the incident light 2 is condensed by the micro condensing lens 100 into b / a. And the light flux 3 is not diffused. The space between the lens 100 and the prism 200 is air having a refractive index of 1.

In the above image pickup apparatus, the prism body 2
As for the physical properties of the material of No. 00, the refractive index nd is 1.58, the Abbe number νd is 30, and the wavelength dependence characteristic of the refractive index is shown in FIG. 3 at the d-line of wavelength 587.6 nm. Try to calculate. If the light condensed by the condenser lens 100 is sufficiently narrowed, the incident angle 45
The light of a degree is refracted at a depth of 1219 μm from the incident point and is color-spectral-spectral. Now, taking one prism part and showing it, the spectral position from red to blue is 15 μm at a position 400.2 μm away from the straight traveling position of light as shown in FIG.
Range. FIG. 1C is an enlarged view of a part of the image plane of the image sensor 300. The above-mentioned color spectral position extends over a range of 15 μm, but in this range, 700
Light having a wavelength of nm to 400 nm is irradiated, and this is repeatedly arranged in stripes. 700 nm
Since a wavelength of 400 nm includes RGB, RGB pixels are formed and placed at each spectral position to form a color solid-state image sensor.

FIG. 2 shows the above-mentioned micro condenser lens 10
The cross-sectional structure of 0 is shown. This micro condenser lens 1
In each of the lens units 00, a semi-cylindrical convex lens is formed in a stripe shape on one surface, and each of the front surface side convex lens groups corresponds to each of the above-mentioned prism portions. A back-side convex lens group is formed so as to face the other surface of the convex lens group of the micro-condensing lens 100. The convex lens group is for irradiating the opposite prisms with incident light. is there.

FIG. 4 shows an example of an optical image forming surface of the solid-state image pickup device 300 corresponding to the above-mentioned specific optical system.
One spatial pixel is set as an area of 15 μm × 15 μm,
The space pixels are divided into RGB regions. A photoelectric conversion pixel exists in each RGB area.

The gap between the micro condensing lens 100 and the prism body 200 is equal to that of the lens 100 and the prism body 2.
It is an optical material having a refractive index and a low dispersion lower than 00, and is air in the above embodiment. However, when the gap is an optical material other than air, the micro condenser lens 10
The design values of the back-side convex lens and the prism of 0 are different from those in the case of air.

[0013]

As described above, according to the present invention,
Since the color separation system is a prism system, there is no absorption of color filters, the light utilization efficiency is high, and high sensitivity is obtained.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of the present invention.

FIG. 2 is a diagram showing a structural example of the micro condenser lens of FIG.

FIG. 3 is a diagram showing a refractive index of a prism.

FIG. 4 is a diagram showing an example of pixel arrangement of a solid-state image sensor.

FIG. 5 is an explanatory diagram of a conventional solid-state imaging device.

[Explanation of symbols]

100 ... Micro condensing lens, 200 ... Prism body,
300 ... Solid-state image sensor.

Claims (4)

[Claims] 1. A micro-condensing lens having a plurality of lens portions, and a prism body having a plurality of prism portions corresponding to the plurality of lenses, wherein each color light dispersed by each prism portion is A single-plate color solid-state imaging device configured so as to be guided to each corresponding pixel of a solid-state imaging device arranged facing the prism body. 2. The single color light according to claim 1, wherein the respective color lights separated by one of the prism parts correspond to RGB pixels arranged in one spatial pixel of the solid-state image pickup device. Plate color solid-state imaging device. 3. The single-plate color solid-state image pickup device according to claim 1, wherein a gap is provided between the micro condenser lens and the prism portion. 4. The color solid-state image pickup device according to claim 3, wherein the gap is filled with an optical material having a refractive index and a low dispersion ratio lower than those of the micro condenser lens and the prism main body.