JPH0591420A - Solid-state image pickup device - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide a solid-state imaging device that substantially expands the dynamic range in one screen and makes deterioration of image quality less likely to occur. A light transmitting member 13 having a light transmittance that decreases as the incident light intensity increases is provided on the front surface of the light incident surface of a solid-state image sensor 12 that generates an electrical signal corresponding to the intensity of the incident light. There is.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state image pickup device for converting an incident optical image into an electric signal, and more particularly to a solid-state image pickup device suitable for use in an electronic still camera, a video camera or the like.

[0002]

2. Description of the Related Art As is well known, as shown in FIG. 4, a solid-state image pickup device for converting an optical image of a photographed object into an electric signal has a plurality of photoelectric conversion characteristics (in the case shown in the figure) having equivalent photoelectric conversion characteristics. 25) sensitive pixels 11, 11, ...
Are arranged in a plane horizontally and vertically,
The photosensitive pixels 11, 11, ... Generate electric signals corresponding to the intensity of incident light.

The photoelectric conversion characteristics of each of the photosensitive pixels 11, 11, ... As shown by the solid line in FIG.
Until then, the noise level D is dominant in the output, and when the intensity of the incident light is between A and B, an output proportional to the intensity of the incident light is obtained.
When the intensity of the incident light is B or more, the output becomes the saturation level E.
Therefore, the photosensitive pixels 11, 11, ... Have a dynamic range between the incident light intensities A and B.

However, in the conventional solid-state image pickup device provided with the photosensitive pixels 11, 11, ... Having the above-mentioned photoelectric conversion characteristics, a low-luminance part and a high-luminance part are mixed in one screen. In this case, the output of the photosensitive pixels 11, 11, ... Corresponding to the high-luminance portion becomes the saturation level E and the image quality deteriorates, and when the luminance is particularly high, blooming, smear, etc. occur and the image quality further deteriorates. There is a problem.

[0005]

As described above, the conventional solid-state image pickup device has a problem that the dynamic range in one screen is narrow and the image quality is easily deteriorated.

Therefore, the present invention has been made in consideration of the above circumstances, and it is an object of the present invention to provide an extremely good solid-state image pickup device which substantially expands the dynamic range in one screen and makes it difficult to cause deterioration of image quality. To aim.

[0007]

A solid-state image pickup device according to the present invention transmits light to the front surface of a light-incident surface of a solid-state image pickup element which generates an electric signal corresponding to the intensity of incident light, as the incident light becomes stronger. A light transmitting member whose rate is reduced is installed.

[0008]

According to the above structure, the high-luminance portion is reduced in intensity of the luminance by the light transmitting member and is incident on the solid-state image pickup element, so that the dynamic range in one screen is substantially reduced. It is possible to enlarge the image quality and prevent the deterioration of the image quality.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. In FIG. 1, a light transmitting plate 13 is installed on the front surface of the light incident surface of the solid-state imaging device 12 including a plurality of photosensitive pixels 11, 11, .... The light transmitting plate 13 is provided for each of the photosensitive pixels 11, 11,
...... A plurality of segments 14, 14 respectively corresponding to
……have. As shown in FIG. 2, the light transmission characteristics of the light transmission plate 13 have a property that the intensity of the transmitted light decreases as the incident light increases, that is, the light transmittance decreases.

Such a light transmitting plate 13 is used for the solid-state image pickup device 1
By installing it on the front surface of 2, each photosensitive pixel 11,1
As shown in FIG. 3, the photoelectric conversion characteristics of 1, ... Are a combination of the characteristics shown in FIG. 4 and the characteristics shown in FIG. Therefore, in the photosensitive pixels 11, 11, ..., Outputs corresponding to the intensity of the incident light can be obtained between the intensities of the incident light A to C, as compared with the conventional example shown in FIG. The dynamic range in one screen can be expanded substantially,
Even for a subject in which a low-luminance portion and a high-luminance portion are mixed in the screen, the photosensitive pixels 11, 1 corresponding to the high-luminance portion
It becomes difficult for the outputs of 1, ... To reach the saturation level E, and the deterioration of image quality is less likely to occur. The present invention is not limited to the above-described embodiments, but can be variously modified and implemented without departing from the scope of the invention.

[0011]

As described in detail above, according to the present invention,
It is possible to provide a very good solid-state imaging device that substantially expands the dynamic range in one screen and makes it difficult for image quality to deteriorate.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a solid-state imaging device according to the present invention.

FIG. 2 is a diagram showing the characteristics of the light transmitting plate of the example.

FIG. 3 is a diagram showing photoelectric conversion characteristics of the same example.

FIG. 4 is a perspective view showing a conventional solid-state image sensor.

FIG. 5 is a diagram showing photoelectric conversion characteristics of the conventional device.

[Explanation of symbols]

11 ... Photosensitive element, 12 ... Solid-state imaging element, 13 ... Light transmitting plate, 14 ... Segment.

Claims (1)

[Claims] 1. A light transmissive member, whose light transmittance decreases as the intensity of incident light increases, is provided in front of a light incident surface of a solid-state image pickup device that generates an electrical signal corresponding to the intensity of incident light. A solid-state image pickup device comprising: