JPS583485A - Color image pickup device - Google Patents

Abstract

PURPOSE:To improve color balance and to increase sensitivity, by changing each effective area of color filters provided corresponding to picture elements and controlling each color component output, and adjusting an output signal ratio of each color component. CONSTITUTION:Color filters G, R and B provided at a light incident plane of a solid-state image pickup element are adjusted with the effective areas respectively. That is, an effective area of color filters R, G and B to each picture element 1a of the image pickup element, that is, an area actually transmitting light is variably set. The adjustment of the effective area of the color filters R, G and B allows the output of each chroma component to independently be adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color imaging device having a highly practical and simple structure capable of obtaining an imaging screen output with good color tone and sensitivity.

Recently, imaging devices such as a nine-color television camera and other imaging devices using semiconductor imaging devices such as COD+BBD have been attracting attention. This type of color imaging device is configured such that a plurality of color filters are arranged to correspond to each pixel of an image sensor, and output signals of nine color components corresponding to the color filters are obtained from each pixel.

However, in an imaging device such as a CCD, the spectral characteristics in the wavelength range used for color telephotography are not flat, and generally exhibit maximum sensitivity at a wavelength around 700%. Therefore, it is necessary to correct this spectral sensitivity characteristic.
In other words, if the characteristics of the image pickup device were to remain as they were, the difference in output between, for example, a blue signal and a red signal would become large, resulting in a significant loss of color balance, and as a result, the image pickup screen would deteriorate.

Conventionally, therefore, a cyan filter or the like is provided over the entire surface of the image sensor, thereby reducing the difference in output between the red signal and the blue signal and achieving balance. However, designing the characteristics of such color filters must be done in conjunction with each other and is very complicated. Moreover, the amount of input light is reduced by the correction filter, resulting in a decrease in the brightness signal and a decrease in the sensitivity of the camera.

The present invention has been made in consideration of these circumstances, and its purpose is to provide a simple and highly practical color imaging device that has excellent color balance and high sensitivity.

That is, the present invention controls the output of each color component by changing the effective area of each color filter arranged corresponding to one pixel without using a correction filter, and in this way, the output signal ratio of each color component can be adjusted. The above-mentioned objective has been effectively achieved by adjusting the color to obtain color photography with excellent color and contrast and high sensitivity.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram of an embodiment apparatus, and FIG. 2 is a layout configuration diagram of color filters.

Color filters 2 are disposed on the imaging surface of a solid-state imaging device 1 such as a CCD, corresponding to each pixel, and a color separation optical system is configured. This color filter 2 is a green filter G.
, red filter RJ'll filter B are arranged as shown in FIG. That is, the green filter G corresponds to each pixel, and for each pixel, one green filter G is applied to every other pixel in the vertical and horizontal directions.
The red filters R and the blue filters B are arranged in a so-called checkerboard pattern, and the red filters R and blue filters B are arranged alternately in the remaining pixel area, resulting in a nine structure. Thus, the output signal of each pixel read out by scanning the solid-state image sensor 1 is amplified to a predetermined level via the amplification a3, and then the output signal is amplified to a predetermined level via the amplification a3.
They are led to steps 4h, 4b, and 4c, respectively. These switch circuits -a+#b, #@ correspond to each color component, and sample the color signals mixed in the above output signal point-sequentially at a predetermined period. This is to extract the ring. In this case, if the switch circuit dm extracts the green component, the switch circuit 4b extracts the red component, and the switch circuit 4@ extracts the back component, then the switch circuit 4a extracts the sun! The ring period is set twice for switch circuits 4b and 4@, and switch circuit 4
b + 4 e's sun! The ring phase is shifted by 1/2.

Therefore, each color component signal separated and extracted in this way is sent to a low-frequency circuit j a + j b
It is then outputted as color code I via r j g. , - By the way, each filter G of the color filter 2.

The effective areas of R and B are respectively adjusted as shown in FIG. That is, color filters G and B are applied to each pixel 1a of the image sensor 1 indicated by a broken line.

The effective area of R, that is, the area through which light actually passes, is variably set. Filters G and B forming color filter 2
, R have a structure in which they are each divided into regions by light-transmitting portions 1, and here, the effective area of the red filter R is particularly set to be narrow.

As shown in FIGS. 4 and 5, the CCD, which is the solid-state image sensor 1, has maximum sensitivity around a wavelength of 700.
It has a sensitivity characteristic as shown in characteristic a. For this reason, in the past, an infrared filter and an infrared filter as shown in FIG. 4 have been used to balance the spectral sensitivity characteristics on the long wavelength side. However, this t
Until then, the above-mentioned COD characteristics still remain, and the signal of the red component becomes stronger than the signal of the pond color component. Particularly in COD, there is a problem in that charge leakage occurs between pixels, and color mixing is likely to occur between a pixel for one red and other pixels adjacent to it. Therefore, conventionally, a correction filter as shown by characteristic a in FIG. 4 has been used to further reduce the red component light. Therefore, this correction filter reduces light components outside of red meat, leading to a decrease in color sensitivity.In contrast, this device does not use a correction filter such as red meat. By adjusting the effective area of each filter, the output of each color component can be adjusted independently, as shown in FIG. Moreover, unlike the case where a correction filter is used, it does not affect other color components, so there is no deterioration of the sensitivity characteristics. Therefore, it is possible to easily adjust the color balance and obtain an imaging screen with excellent color tone and high sensitivity.

As described above, according to the present invention, an imaging screen with excellent color tone can be obtained by easily adjusting the signal output ratio of each color component. Furthermore, the sensitivity of the solid-state image sensor is not impaired. In addition, the filter design can be done independently for each color component, which is easy to implement, and the spectral characteristics do not change.

Note that the present invention is not limited to the above embodiments. For example, it is of course possible to adjust the output of color components other than the red signal, and the color filter may be striped. Furthermore, the solid-state image sensor is not limited to CCD K. In short, the present invention can be implemented with various modifications without departing from the gist thereof.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an apparatus showing one embodiment of the present invention, and FIG.
The figure is a diagram showing the arrangement and configuration of color filters, Figure 3 is a diagram showing the relationship between the effective area of color filters and pixels, and Figures 4 and 5 are C
It is a diagram showing the relationship between the sensitivity characteristics of the OD, the spectral characteristics of the filter, and the output and characteristics of each color component. 1... solid-state image sensor, 2... color filter, 3...
Amplifier, 1m, #b+Je-* switch, circuit, 61°5
b, 5@...Low frequency f wave@road, C...Color code,
11... Pixel, 1... Continuous light section.

Claims (1)

[Claims] In a color imaging device in which a plurality of color filters are arranged corresponding to the pixels of an image sensor, and an output signal of a color component corresponding to the color filter is obtained from each pixel, the effective area of each color filter is changed to A color imaging device characterized in that an output signal ratio of color components corresponding to a filter is determined.