JPH04217184A - Solid-state image pickup device - Google Patents

Abstract

PURPOSE:To reduce an ghost image and flare at a low cost with simple configuration by providing a light shielding board composed of a black member out of the range where the image pickup light on the protection glass surface on the side where the image pickup light of the solid-state image pickup element is made incident. CONSTITUTION:From among lights made incident on a first prism 10 from an image pickup lens 1, blue light component is all reflected by a dichroic film 9. From among lights passing through the dichroic film 9, red light component is all reflected by a dichroic film 11. Further, the lights passing through the dichroic film 11 reach solid-state image pickup elements 7B, 7R, and 7G respectively. Here, a light shielding board 53 is equipped on the surface of a protection glass 52 on the side of each solid-state image pickup element where the image pickup light is made incident. This light shielding board 53 is made of a black rubber member or black coated metal board. Thus, the ghost image and flare can be reduced at a low cost with simple configuration.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention particularly relates to a charge-coupled device (CC) device which reduces flare or ghost and improves image quality.
The present invention relates to a solid-state imaging device using a solid-state imaging device such as D).

0002

[Prior Art] In recent years, in solid-state imaging devices for color television, imaging light passing through an imaging lens is separated into a red component, a green component, and a blue component by a color separation prism, and a subject image of each color component is obtained. A standard color television signal is formed from each image output signal obtained by imaging with the solid-state image sensor and output.

The structure of a conventional solid-state imaging device for color television of this type will be explained with reference to FIG. As shown in the figure, the solid-state imaging device includes an imaging lens 101, an infrared cut filter 102, and a color temperature conversion filter 103.
, ND filter 104, optical low-pass filter 10
5. Three-color color separation optical unit 106, solid-state image sensor 10
7R, 107G, 107B, a glass block 108, etc.

[0004] Here, the three-color color separation optical unit 106 is
First, a first film for extracting the blue light component has a blue reflective dichroic film 109 that mainly reflects the blue light component.
a second prism 112 for extracting a red light component and having a red reflective dichroic film 111 arranged after the first prism and mainly reflecting a red light component; A third prism 113 for extracting a green light component is bonded to a surface on which a reflective dichroic film 111 is provided. A blue channel trimming filter, a red channel trimming filter, and a green channel trimming filter are provided on each output surface as necessary. Furthermore, a minute air layer is provided between the first prism 110 and the second prism 112 in order to efficiently totally reflect the red light component. Above, 3
In the vicinity of each output surface of the color separation optical unit 106, the solid-state image sensors 107R, 107G, and 107B adjust the subject image of each color component imaged by each solid-state image sensor to a predetermined position (registration adjustment). In this state, it is fixed with a glass block 108. The adjustment is performed between each output surface of the three-color color separation optical unit 106 and the entrance surface of the solid-state image sensor so that there is no interference between each output surface of the three-color color separation optical unit and the entrance surface of the solid-state image sensor. There is an air layer in the.

To explain the operation in the above configuration, FIG.
The blue light component of the light incident on the first prism 110 from the imaging lens 101 is totally reflected by the blue reflection dichroic film 109, and then passes through the total reflection surface and the blue channel trimming filter, and is then transferred to the blue solid-state image sensor. It reaches 107B. On the other hand, blue reflective dichroic film 1
Of the light that has passed through 09, mainly only the red light component is totally reflected by the red reflection dichroic film 111, and then passes through the total reflection surface and the red channel trimming filter, and then reaches the red solid-state image sensor 107R. Furthermore, the light that has passed through the red reflective dichroic film 111 becomes a green light component and reaches the green solid-state image sensor 107G via a green channel trimming filter. The above is the configuration and operation of the conventional solid-state imaging device for color television.

[0006]

[Problems to be Solved by the Invention] In the configuration of such a conventional solid-state imaging device for color television, there is a
Multiple lenses, infrared cut filters, color temperature conversion filters, ND filters, various prisms for color separation,
A protective glass for the solid-state image sensor is arranged, and some reflected light is generated at the interface between them, and the extra reflected light goes around and hits the light receiving surface of the solid-state image sensor, reaching the image plane and forming an image. However, there are problems such as generation of so-called ghost images and flare that does not form an image even if it reaches the image plane.

[0007] Conventionally, several methods listed below have been taken to solve the above problem. (1) Improve the performance of anti-reflection films as a measure against flare caused by interface reflections. (2) The performance of the dichroic film is also improved to prevent the generation of extra light that becomes a flare component. (3) Apply black paint to the outer periphery of the prism. (4) Provide a slit in the prism. Although these measures have been taken and improvements have been made, it is still not enough. The present invention has been made to solve the above problems, and an object of the present invention is to provide a solid-state imaging device that further reduces flare and ghost images with a simple configuration.

[0008]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a light-shielding plate made of a black material on a protective glass surface provided on a solid-state image sensor in a portion other than a range through which incident imaging light is transmitted. This is to block excess light from reaching the light receiving section of the solid-state image sensor.

[0009]

[Operation] The present invention realizes a solid-state imaging device that can obtain good image quality by blocking excess light from reaching the light-receiving section of the solid-state imaging device with a simple configuration. It is something to do.

0010

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view showing the structure of a solid-state imaging device for color television according to the present invention, and FIG. 2 is a conceptual diagram of the main parts of the solid-state imaging device. As shown in the figure, the solid-state imaging device includes an imaging lens 1, an infrared cut filter 2, a color temperature conversion filter 3, an ND filter 4, an optical low-pass filter 5, a three-color color separation optical unit 6, and a solid-state imaging device 7R.
, 7G, 7B, and a glass block 8. As shown in FIG. 2, the solid-state image sensors 7R, 7G, and 7B have a chip 50 (a photodiode on a silicon substrate,
The chip includes a solid-state image sensor package 51, a protective glass 52 for the solid-state image sensor provided on the front surface of the chip, and a light-shielding plate 53 attached to the protective glass 52. .

As shown in FIG. 3, the light shielding plate 53 has the following structure.
The solid-state image sensor 7R,
A range that does not block the light condensed on the imaging plane of 7G and 7B (depending on the type, there are some that have an accumulation section in addition to the light receiving section, but it is sufficient to focus the light on the light receiving section), the minimum window 60
It has an outer shape slightly smaller than that of the solid-state image sensor, and is further provided with an adhesive reservoir hole 61 as required. By providing the adhesive reservoir hole 61, the light shielding plate 53 can be placed on the surface of the solid-state image pickup device protective glass 52, and black adhesive can be poured into the hole 61 while aligned. Can be fixed with adhesive. If there is no adhesive reservoir hole 61, the solid-state image sensor 7R,
Adhesive may adhere to the portion through which light condensed on the imaging planes of 7G and 7B passes through, causing image defects similar to dust, scratches, etc. The light shielding plate 53 is made of a black rubber material or a metal plate coated with black paint. Of course, the same effect can be obtained by forming a film of silicon oxide or the like on the surface of the protective glass 52 or by printing black ink on the surface of the protective glass 52, but this method will increase the cost compared to the above method. It is.

The three-color color separation optical unit 6 first includes a first prism 10 for extracting the blue light component, which has a blue reflective dichroic film 9 that mainly reflects the blue light component.
a second prism 12 for extracting a red light component, which is disposed after the first prism and has a red reflective dichroic film 11 that mainly reflects the red light component; and a red reflective dichroic film of the second prism 12. and a third prism 13 for extracting the green light component, which is joined to the surface on which the prism 11 is provided. A blue channel trimming filter, a red channel trimming filter, and a green channel trimming filter are provided on each output surface as necessary. Furthermore, a minute air layer is provided between the first prism 10 and the second prism 12 in order to efficiently totally reflect the red light component. The solid-state imaging devices 7R, 7G, and 7B each have a light-shielding plate 53 attached to the light-shielding plate 53 in the vicinity of each output surface of the three-color color separation optical unit 6. The image is fixed to a glass block 8 with the image adjusted to a predetermined position (registration adjustment). Each exit surface of the three-color separation optical unit 6 and the solid-state image sensors 7R, 7G, 7B
An air layer is provided between the incident surfaces so that there is no interference between the respective output surfaces of the three-color separation optical unit and the incident surface of the solid-state image sensor during the adjustment.

To explain the operation in the above configuration, FIG.
, the blue light component of the light incident on the first prism 10 from the imaging lens 1 is totally reflected by the blue reflection dichroic film 9, passes through the total reflection surface and the blue channel trimming filter, and then passes through the window of the light shielding plate. 60 and reaches the blue solid-state image sensor 7B. On the other hand, among the light that has passed through the blue reflective dichroic film 9, only the mainly red light component is totally reflected by the red reflective dichroic film 1.
After passing through the total reflection surface and the red channel trimming filter, the light passes through the window 60 of the light shielding plate and reaches the red solid-state image sensor 7R. Furthermore, the light that has passed through the red reflective dichroic film 11 becomes a green light component, passes through a green channel trimming filter, and then passes through a window 60 of a light-shielding plate to reach the green solid-state image sensor 7G. Of course, a slit 20 is provided in each of the prisms to prevent flare or ghost images.

FIG. 4 shows data obtained by measuring the amount of flare in the solid-state imaging device of the present invention, and FIG. 6 shows data obtained by measuring the amount of flare in a conventional solid-state imaging device for comparison. The measurement conditions were F1.7, using a flare evaluation chart (test screen with a black window on a white background).
The amount of flare at 2000 Lux was compared. In FIGS. 4 and 6, when the white portion is taken as 100%, the flare amount in the black portions 70 and 71 does not become zero but exceeds 20%. The higher this value is, the more flare there is. As is clear from the figure, the configuration of the present invention can reduce flare. As for ghost images, although it is difficult to quantitatively evaluate them, it has been recognized that they are reduced by the configuration of the present invention compared to conventional ones. As described above, the effect of providing a black light-shielding plate on the protective glass surface for a solid-state image sensor is great.

A similar effect can be expected to some extent by providing a light-shielding window on the prism side, but since the CCD moves during registration, the light-shielding window must be made somewhat larger. By providing a light shielding plate on the CCD side, the size of the transmission window can be minimized, which is very effective.

[0017]

As is clear from the above embodiments, the present invention provides a solid-state imaging device that can reduce flare or ghost images and obtain good image quality with a simple configuration and at low cost. can.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the configuration of a solid-state color imaging device of the present invention.

[Figure 2] Conceptual diagram of main parts of solid-state image sensor

[Figure 3] Conceptual diagram of main parts of light shielding plate

[Fig. 4] Measurement data diagram of flare amount in the configuration of the present invention

[Fig. 5] Cross-sectional view showing the configuration of a conventional solid-state color imaging device

[Figure 6] Measurement data diagram of flare amount in conventional configuration

[Explanation of symbols]

7 Solid-state image sensor 50 chip (photodiode on silicon substrate, C
A device on which a CD, etc. is formed is called a chip) 52 Protective glass for solid-state image sensor 53 Light shielding plate

Claims (1)

[Claims] 1. A solid-state imaging device using a solid-state imaging device, in which a light-shielding plate made of a black material is provided on a portion of a protective glass surface other than the area through which imaging light is transmitted.