JPH10214953A - Solid-state image pickup device, video camera and digital camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To equalize output levels of a red electric signal, a green electric signal and a blue electric signal which are generated with white light is incident on a solid-state image pickup device. SOLUTION: In a substrate part 1 at a solid-state image pickup device, an R-sensor part coverts a red component in incident light into a red electric signal, A G-sensor part coverts a green component in the incident light into a green electric signal, and a B-sensor part converts a blue component in the incident light into a blue electric signal. A color filter 2 which is laminated on the substrate part 1 separates the incident light into a red component, a green component and a blue component in such a way that the red component is transmitted through the R-sensor part, that the green component is transmitted through the G-sensor part and that the blue component is transmitted through the B- sensor part. On-chip lenses 3R, 3G, 3B which are formed on the color filter 2 have a condensing rate corresponding to respective colors in such a way that a red electric signal, a green electric signal and a blue electric signal which are generated when white light is incident become the same level.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state imaging device, and more particularly, to a solid-state imaging device that separates incident light into three primary colors of light (RGB) using a color filter and converts the light into electric signals.

[0002]

2. Description of the Related Art With the advance of integration technology for semiconductor devices, a CCD (Charge Coupled Device) type solid-state imaging device in which functions of photoelectric conversion, accumulation, and charge readout of a large number of pixels are formed into an LSI (Large Scale Integrated Circuit) chip. It has become widespread. Currently, CCD is
It is widely used in digital cameras and video cameras.

In order to color the CCD, a color filter for separating incident light into RGB (R: red, G: green, B: blue) may be arranged on the photoelectric conversion unit. When placing,
Laminating the color filters directly on the substrate of the CCD is superior in positioning accuracy and excellent in mass productivity, rather than laminating the formed color filters on glass.

When white light is decomposed, red, green, and blue should have the same ratio. However, conventional CC
In D, since the transmittance of each color is different depending on the characteristics of the laminated color filters, even if white light is incident,
The generated red electric signal, green electric signal, and blue electric signal are not at the same level.

FIG. 2 is a diagram showing an example of how an electric signal is generated when white light is incident on a conventional CCD. FIG. 2A is a schematic cross-sectional view of one pixel of the CCD. FIG. 2B is a diagram showing an output level of an electric signal generated by making white light incident on the CCD shown in FIG.

The substrate 10 of the CCD has an R sensor for generating a red electric signal, a G sensor for generating a green electric signal, and a B sensor for generating a blue electric signal.
A color filter 12 is laminated on the light incident surface of the substrate unit 10, and transmits only the red component to the R sensor, transmits only the green component to the G sensor, and transmits only the blue component to the B sensor. On the light incident surface of the color filter 12, on-chip lenses 13R, 13G, and 13B are further formed, and the incident light is collected at the center of each sensor.

[0007] When light is incident, such a CCD performs photoelectric conversion according to the amount of light obtained by each sensor, and generates a red electric signal, a green electric signal, and a blue electric signal. As shown in FIG. 2B, the output level of the generated electric signal is non-uniform. Here, the output levels of the green electric signal G, the red electric signal R, and the blue electric signal B decrease in this order due to the characteristics of the color filter 12.

In order to adjust the level of such an output signal, a process called white balance is required in the production process of the CCD. In this step, white light is incident on the CCD, and a human observes an image generated from the output electric signal, and increases or decreases the electric signal of each color.

When the CCD is incorporated in a camera or the like, it is necessary to provide a white balance circuit.

[0010]

However, the white balance process that requires labor and time is originally unnecessary if the output level of the electric signal output from the CCD is constant. Even when a CCD is incorporated in a camera or the like, if the electric signals G, R, and B are constant, the white balance circuit can be omitted, and miniaturization and cost reduction can be expected.

The present invention has been made in view of the above points, and has as its object to provide a CCD type color solid-state imaging device that does not require a white balance step. Another object of the present invention is to provide a CCD that does not require white balance adjustment.
To provide a video camera having a color solid-state imaging device.

Still another object of the present invention is to provide a digital camera having a CCD type color solid-state imaging device which does not require white balance adjustment.

[0013]

According to the present invention, in order to solve the above-mentioned problems, in a solid-state imaging device for converting incident light into an electric signal, a red sensor unit for converting a red component of the incident light into a red electric signal. And a green sensor unit that converts a green component into a green electric signal, a substrate unit that has a blue sensor unit that converts a blue component into a blue electric signal, and a red component that is stacked on the substrate unit and converts the incident light into a red component. , Green component,
A color filter that decomposes into a blue component, transmits the red component to the red sensor unit, transmits the green component to the green sensor unit, transmits the blue component to the blue sensor unit,
An on-chip lens formed on the color filter and having a light-collecting rate corresponding to each color such that a red electric signal, a blue electric signal, and a green electric signal generated when white light is incident are at the same level. And a solid-state imaging device characterized by having:

When converting incident light into an electric signal in such a solid-state imaging device, a sensor unit included in the substrate unit converts the incident light into an electric signal. That is, the red sensor unit converts a red component into a red electric signal, the green sensor unit converts a green component into a green electric signal, and the blue sensor unit converts a blue component into a blue electric signal. Color filters are stacked on the substrate. The color filter decomposes the incident light into a red component, a green component, and a blue component, the red component to the red sensor unit, the green component to the green sensor unit,
The blue component is transmitted through the blue sensor unit. On-chip lenses are further formed on the color filters.
The on-chip lens has a light-collecting rate corresponding to each color so that when white light is incident, the generated red electric signal, blue electric signal, and green electric signal are at the same level.

In such a solid-state imaging device, a red electric signal, a green electric signal, and a blue electric signal generated when white light is incident are at the same level. Therefore, a white balance step and a white balance circuit are not required.

In a video camera or digital camera using such a solid-state imaging device, a red electric signal, a green electric signal, and a blue electric signal generated when white light is incident are the same and have the same level. Therefore, a white balance circuit is not required.

[0017]

FIG. 1 is a diagram showing the principle of a color solid-state imaging device according to the present invention. FIG. 1A is a diagram schematically showing a cross-sectional view of one pixel of a CCD according to the present invention. , (B)
FIG. 3A is a diagram showing an output level of an electric signal generated when white light is incident on the CCD shown in FIG.

The substrate section 1 of the CCD includes an R sensor for generating a red electric signal, a G sensor for generating a green electric signal,
And a B sensor for generating a blue electric signal. A color filter 2 is laminated on the light incident surface of the substrate unit 1 and transmits only the red component to the R sensor, transmits only the green component to the G sensor, and transmits only the blue component to the B sensor.
An on-chip lens 3 having a different light-collecting rate (shape, refractive index) is further provided on a light incident surface of the color filter 2.
R, 3G and 3B are formed, and the incident light is collected at the center of each sensor.

When light is incident, such a CCD performs photoelectric conversion according to the amount of light acquired by each sensor, and generates a red electric signal, a green electric signal, and a blue electric signal. Note that the light transmittance of the color filter 2 decreases in the order of green, red, and blue.

Here, the on-chip lenses 3R, 3G, 3B
The light collection rate is adjusted so that the output level of the generated electric signal becomes uniform. That is, B which generates a blue electric signal from a blue component having a low color filter transmittance
The on-chip lens 3B that collects light at the sensor is formed with a high light collection rate so that the output level of the blue electric signal is the same as the output level of the green electric signal. Similarly, the on-chip lens 3R is configured so that the output level of the red electric signal is the same as the output level of the green electric signal.
B is formed at a light collection rate lower than B and higher than that of the on-chip lens 3G.

The output levels of the red electric signal R, the green electric signal G, and the blue electric signal B are the same because the light-gathering rates of the on-chip lenses 3R, 3G, and 3B are adjusted.
Therefore, a white balance step is not required in the process of producing such a CCD. When such a CCD is incorporated in a video camera, a white balance circuit becomes unnecessary.

Similarly, when such a CCD is incorporated in a digital camera, a white balance circuit becomes unnecessary. In the above description, the case where the present invention is applied to a CCD type color solid-state imaging device has been described.
The present invention is also applicable to an S (Metal Oxide Semiconductor) type color solid-state imaging device or the like.

[0023]

As described above, according to the present invention, the thickness of the on-chip lens is changed according to the transmittance of the red, green, and blue components of the color filter laminated on the solid-state imaging device. The electric signals of the respective colors generated when light enters are at the same level, and the white balance circuit and white balance adjustment are not required.

[Brief description of the drawings]

1A and 1B are diagrams illustrating the principle of a color solid-state imaging device according to the present invention, in which FIG. 1A is a diagram schematically illustrating a cross-sectional view of one pixel of a CCD according to the present invention, and FIG. FIG. 3 is a diagram showing the output level of an electric signal generated when white light is incident on the CCD shown in FIG.

FIG. 2 is a diagram showing an example of how an electric signal is generated when white light is incident on a conventional CCD, wherein (a)
FIG. 3 is a diagram schematically showing a cross-sectional view of one pixel of the CCD, and FIG. 4B shows an output level of an electric signal generated by making white light incident on the CCD shown in FIG. FIG.

[Explanation of symbols]

1 ... substrate part, 2 ... color filter, 3R, 3G, 3
B: On-chip lens.

Claims (4)

[Claims] 1. A solid-state imaging device that converts incident light into an electric signal, comprising: a red sensor unit that converts a red component of the incident light into a red electric signal; and a green sensor unit that converts a green component into a green electric signal. A substrate unit having a blue sensor unit that converts a blue component into a blue electric signal; and a blue component that is stacked on the substrate unit, decomposes the incident light into a red component, a green component, and a blue component, and A color filter that transmits the red component, the green component to the green sensor portion, the blue component to the blue sensor portion, and a color filter formed on the color filter, when white light is incident, A solid-state imaging device comprising: an on-chip lens having a light-collecting rate corresponding to each color such that the generated red electric signal, green electric signal, and blue electric signal are at the same level. Nest. 2. The on-chip lens has a condensing rate for each color, which is proportional to a reciprocal of a transmittance of a red component, a transmittance of a green component, and a transmittance of a blue component of the color filter. The solid-state imaging device according to claim 1, wherein: 3. A video camera having a solid-state imaging device that outputs a red electric signal, a green electric signal, and a blue electric signal at the same level with respect to incident white light. 4. A digital camera having a solid-state imaging device that outputs a red electric signal, a green electric signal, and a blue electric signal at the same level with respect to incident white light.