JPS59100686A - Solid-state image pickup device - Google Patents

Abstract

PURPOSE:To apply all pickup under the optimum white balance at all times by providing a photo diode having a color transmission filter of three primary colors with red, green and blue and a white balance detecting section made of a diffusion plate in front of the diode. CONSTITUTION:Each sensor 3 is of the same constitution, and the white balance detecting section comprising photo diodes 6r, 6g, 6b having color transmission filters 5r, 5g, 5b to three primary colors with red, green and blue and the opaque diffusion plate prvided in front of each photo diode are constituted. Then, the diodes 6r, 6g, 6b diffuse the light from the object by the diffusion plate 7 and detects it at the filters 5r, 5g, 5b with spectroscopy. The output of the diode 6r corresponding to the red color, the output of the diode 6b corresponding to the blue color are compared with the output of the diode 6g corresponding to the green color at comparators 8, 9, and the relative gain of the three primary color signals required for the color temperature correction of the object is detected.

Description

TECHNICAL FIELD The present invention relates to a solid-state imaging device that is capable of continuously correcting white balance in accordance with the color temperature of illumination irradiated onto a subject.

Background Art Color cameras generally require color temperature correction that changes the relative gain of the three primary color signals depending on the color temperature of the light source.
If this correction is incomplete, white will not be reproduced as white -/-. This is because the spectrum of each wavelength differs depending on the color temperature, and countermeasures such as color temperature conversion by inserting a color temperature conversion filter and electrical correction of the relative gains of the three primary color signals are required. Conventionally, electrical correction here has been performed by turning on a white balance switch while imaging a white subject with a camera, and adjusting the gains of the red signal and blue signal relative to the green signal.

For this reason, there is no problem with imaging while the lighting conditions are maintained during white balance adjustment, but if the weather changes from sunny to cloudy after adjustment, or if you switch from outdoor to indoor imaging, the lighting conditions may change. If the white balance is different, the white balance must be adjusted at the same time, resulting in disadvantages such as missing an opportunity to take an image or having to take an image without obtaining an appropriate white balance.

DISCLOSURE OF THE INVENTION The present invention eliminates the above-mentioned drawbacks, and includes a photodiode having color transmission filters for the three primary colors of red, green, and blue outside the effective imaging area of the solid-state image sensor within the image circle of the objective lens, and By installing a white balance detection unit consisting of a diffuser plate that diffuses incident light on the front of the photodiode, the color temperature of the subject can be constantly monitored and the relative levels of the three primary color signals required for white balance adjustment can be continuously detected. An object of the present invention is to provide a solid-state imaging device that can detect images in a solid state.

In order to achieve this object, the present invention provides a solid-state imaging device having a predetermined effective imaging area within the image circle of the objective lens, and outside the effective imaging area of this solid-state imaging device,
Further, within the image circle, there is provided a white lance detection unit consisting of a photodiode having color transmission filters of three primary colors and a diffuser plate for diffusing incident light in front of the photodiode. be.

According to the present invention, the photodiode for color temperature correction is
The solid-state image sensor and photodiode always receive light from the same subject through the diffuser plate, so it is possible to continuously adjust the white balance to the appropriate level under any imaging conditions. Since they are formed on the same substrate, the spectral sensitivity characteristics of the two can be more closely matched, and this provides excellent effects such as white balance adjustment with extremely little error.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 and 2 are a front view and a schematic configuration diagram, respectively, showing an embodiment of the solid-state imaging device of the present invention.

In the figure, the solid-state imaging device/ is equipped with a solid-state imaging device 2 using a CCD (charge-coupled device) and one sensor 3 for detecting the color temperature of the object, in the image circle IIa of the objective lens. It is the composition.

The effective imaging area of the solid-state imaging device 2 is the image circle l
It is represented by a rectangle inscribed in Ia, and the sensors 3 are arranged outside each side of the rectangle. Color transmission filter 3r corresponding to the three primary colors of green and blue! ;
Three photodiodes 6r, 6g+ with g, jb
”- and these fort diodes 4r,'g+g
A white balance detection section is constituted by a milky-white diffuser plate 7 provided in front of b. Therefore, each photodiode l
r, 6g.

+b is a diffusion plate β that diffuses the light from the subject, and a color transmission filter! rr,! Detected by spectroscopy using g and jb. In the case of this embodiment, the output of the photodiode Ar corresponding to red and the output of the photodiode 6b corresponding to blue are as follows:
Each comparator! , 51CL compares the output of the photodiode tg corresponding to green to detect the relative gain of the three primary color signals necessary for correcting the color temperature of the subject.

Note that these relative gains can be obtained separately for each sensor 3, but by using the average value of the values,
It is possible to compensate for variations between sensor positions.

In addition, instead of a simple average, the output of each sensor 3 can be weighted and a weighted average value can be used.On the other hand, the telegraph signals of the subject obtained by the solid-state image sensor 2 are red, green, green, and red, respectively. Amplifier 10 r , 1 for blue
0 g.

/(1) After being amplified by b, gamma correction circuit //r,
It passes through //g and //b and is sent to the encoder circuit /,2.

Here, amplifiers 10r, 10b and gamma correction circuit //r
.

//1) Gain control circuits zaa and ria are provided between the comparators f and 9, respectively, and are connected to the comparators f and 9, respectively.
? The red and blue gain control circuits zaa and 9a are controlled by the correction signal obtained in .

Therefore, the red and blue signals obtained from the solid-state image sensor 2 are gain-adjusted with the green signal as a reference, and level adjustment is continuously performed to obtain an appropriate white balance.

In this way, the solid-state continuous image device l having the above structure can constantly correct the color temperature using the sensor 3 installed near the solid-state image sensor 2, so it can always correct the color temperature of any subject under the optimal white balance. In addition, the solid-state image sensor 2 and the seven sensors 3 can be formed on the same silicon substrate, and in that case, the spectral sensitivity characteristics of the two can be matched. Therefore, white balance adjustment with extremely few errors is possible.

In the above embodiment, the number of sensors 3 for detecting the color temperature of the object is not limited to 1, but may be 1 to 3, or 5 or more.

[Brief explanation of the drawing]

1 and 2 are a front view and a schematic configuration diagram, respectively, showing an embodiment of the solid-state imaging device of the present invention. 1... Solid-state imaging device, 2... Solid-state imaging device, 3...
・Sensor, G...Objective lens, Fa...Image circle,! ;r, jg,,t b--・Color transmission filter, 6r, 6g. 6b...Photodiode, 7...Diffusion plate. 7-

Claims (1)

[Claims] A solid-state imaging device having a predetermined effective imaging area within the image circle of the objective lens; a photodiode having color transmission filters for three primary colors outside the effective imaging area of the solid-state imaging device and within the image circle; A solid-state imaging device characterized in that a white balance detection section comprising a diffuser plate that diffuses incident light is provided in front of a photodiode.