JP2722972B2 - Solid-state imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digitized solid-state image pickup device, and more particularly to a solid-state image pickup device capable of reducing adjustment work in mass production.

[0002]

2. Description of the Related Art In recent years, signal processing of a solid-state imaging device has been digitized due to the progress of semiconductor technology. Regarding the digitization of solid-state imaging devices, see, for example, Journal of the Institute of Television Engineers of Japan, Vol. 45, no. 9 (199
1), pp 1060-1066, Ohtsubo (Hitachi), a special issue, “Image Sensor and Peripheral Circuits, 4. Digitization of Camera Signal Processing Circuit,” etc., and a detailed description thereof is omitted here. FIG. 3 is a block diagram showing an example of a conventional digital solid-state imaging device. Here, a lens system and the like are omitted for simplification.

In FIG. 3, a solid-state imaging device (CCD) 1
Outputs photoelectric conversion of a subject image formed by a lens system (not shown) as a time series of one-dimensional analog sample values. This analog sampled value signal is a CDS composed of a sample hold circuit and an AGC circuit (amplifier circuit).
/ AGC circuit 2, the CDS / AGC circuit 2 extracts an image signal component from the analog sampled value signal, amplifies and outputs it. The output of the CDS / AGC circuit 2 is A / D
The data is converted by the converter 3 into a digital image signal which is a time series of digital data. This digital image signal is input to the digital signal processing circuit 4.

The digital signal processing circuit 4 assumes that the CCD 1 is a color CCD having a color filter array.
Color signal processing such as color separation, RGB matrix, and gamma correction;
Luminance signal processing such as Y filter, enhancer, and gamma correction;
A signal processing circuit for performing encoder processing for performing NTSC / PAL color modulation and synchronization, a synchronizing signal generating circuit for supplying a synchronizing signal to this signal processing circuit and an external timing generating circuit 7, and an external microcomputer 8 The microcomputer 8 includes a microcomputer interface circuit for supplying input parameters and supplying image information such as white balance and black balance to the microcomputer 8, and a so-called digital image signal output from the A / D converter 3. Perform video processing.

The timing generation circuit 7 synchronizes with a synchronization signal generated by a synchronization signal generation circuit in the digital signal processing circuit 4 to generate a CDS / AGC circuit 2, an A / D converter 3,
Digital signal processing circuit 4, D / A converter 5 (5a, 5
b) Supply the required pulse signals to the digital CCD drive circuit 6 and the microcomputer 8 respectively. C
The CD drive circuit 6 converts the input pulse signal into a drive signal for the CCD 1 and supplies it to the CCD 1. Further, the microcomputer 8 controls the digital signal processing circuit 4 based on the pulse signal input from the timing generation circuit 7 and the image information read from the digital signal processing circuit 4. Then, the digital Y and C signals output from the digital signal processing circuit 4 are D / A converters 5a and 5b, respectively.
And converted into analog Y and C signals and output.

[0006]

The adjustment operation of the above-described conventional solid-state imaging device is performed as follows. That is, in FIG. 4, 10 is the solid-state imaging device shown in FIG. 3, 11 is a lens system, 12 is a test chart, 13 is a light, 14
Denotes an image processing device (consisting of an A / D converter 15, a timing generation circuit 16, and a data processing device 17 such as a personal computer), which captures an image under such an adjustment environment, and digitizes / data Perform analysis. Then, the analysis data is supplied to the microcomputer 8 in the solid-state imaging device 10 via a serial interface such as RS232C, and stored in the nonvolatile memory element built in the microcomputer 8. Such adjustment work is a computerization of the work conventionally performed by analog-type imaging devices. The adjustment environment is complicated and not always suitable for mass production. Have not enjoyed it.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems of the prior art, the present invention provides a solid-state imaging device for photoelectrically converting a subject image and outputting the same, and an image based on a signal output from the solid-state imaging device. A sample hold / amplifier circuit for extracting, amplifying and outputting a signal component, an A / D converter for converting an image signal output from the sample hold / amplifier circuit into a digital image signal and outputting the digital image signal, D
A digital signal processing circuit for performing signal processing on a digital image signal output from the converter; a digital driving circuit for driving the solid-state imaging device;
A timing generation circuit for supplying a necessary timing signal to the amplifier circuit, the A / D converter, the digital signal processing circuit, and the digital drive circuit; and a microcomputer for supplying a control signal required for the digital signal processing circuit. A solid-state imaging device provided with a nonvolatile memory element for writing photoelectric conversion characteristics of the solid-state imaging element and the sample-hold / amplification circuit as digital data; A memory element is mounted on a first substrate, and the A / D converter, the digital signal processing circuit, the digital drive circuit, the timing generation circuit,
The microcomputer is mounted on a second substrate, and after assembling the first substrate and the second substrate, the microcomputer reads the digital data written in the nonvolatile memory element, and reads the digital signal. An object of the present invention is to provide a solid-state imaging device characterized in that a processing circuit is initialized.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A solid-state imaging device according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram showing an embodiment of the solid-state imaging device according to the present invention, and FIG. 2 is a diagram for explaining a data writing operation in the solid-state imaging device according to the present invention. In FIG. 1, the same parts as those in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted.

As can be seen from FIG. 1, what is newly added according to the present invention is a nonvolatile memory element 9. By the way, in a digitized solid-state imaging device, CCD 1
And CDS / A which is a sample hold circuit and an amplifier circuit
Paying attention to the fact that only the GC circuit 2 is an analog circuit, in the solid-state imaging device of the present invention, as shown in FIG.
And the CDS / AGC circuit 2 and the newly added nonvolatile memory element 9 are mounted on one board A, and the other A / D converters 3 to the microcomputer 8 are mounted on another board B. Divides into two blocks. Thus, all the circuits on the substrate B are digital circuits, and the circuit on the substrate A
By grasping only the variations in the characteristics of the circuit (including the photoelectric conversion characteristics and the spectral characteristics of the CCD 1), the characteristics of all the circuits can be determined.

Then, accurate information on the characteristics of the circuit on the substrate A and its variation is given in the form of digital data to the nonvolatile memory element 9 mounted on the same substrate as described later. In this way, after assembling the substrate A and the substrate B, the microcomputer 8 operates the nonvolatile memory element 9.
, The information (digital data) is read from the digital signal processing circuit, and the setup (initialization) of the digital signal processing circuit 4 is automatically executed based on the read information.

Here, an operation of writing data in the nonvolatile memory element 9 will be described with reference to FIG. As shown in FIG. 2, an A / D converter 21, a CCD driving circuit 22, a timing generation circuit 23, a data processing device 2 are used as measurement jigs when writing data to the nonvolatile memory element 9.
A drive device 20 for measuring the characteristics of the circuit of the substrate A and a projector 25 for projecting various lights onto the CCD 1 are prepared, and the drive device 20 is connected to each terminal of the substrate A. . In FIG. 2, 9a is a data input / output terminal, and 9b is a control terminal for controlling writing / reading of data. Here, since only data is written, the terminal 9a operates as an input terminal.

Thus, the CCD 1 and the CD on the substrate A are
The S / AGC circuit 2 is driven in the same state as in FIG. When the sensitivity characteristic data is obtained, for example, the CCD 25 is irradiated with light having a predetermined color temperature and illuminance from the projector 25 by the A / D converter 21.
CD so that the obtained image signal data has a predetermined value.
The AGC control data of the S / AGC circuit 2 is obtained. By this operation, the variation in the sensitivity of the CCD 1 is compensated by the gain of the CDS / AGC circuit 2. At this time, the obtained A
Although the GC control data varies from one CCD substrate to another, the reproduction accuracy does not vary because the data is expressed in digital quantities. Further, if the CCD 1 is a color CCD, sensitivity data for each color filter can be obtained at the same time, so that they can be used as basic data for obtaining a white balance later. After obtaining the basic data in this manner, these are written into the nonvolatile memory element 9 in a predetermined format, and the data collection operation is completed. As a result, the nonvolatile memory element 9 includes the CCD 1 and the CDS / AG
The photoelectric conversion characteristics by the C circuit 2 are written as digital data.

When the solid-state imaging device is started after assembling the substrates A and B, the microcomputer 8 reads the digital data written in the nonvolatile memory element 9 and initializes the digital signal processing circuit 4. Therefore, there is no need for complicated and extensive adjustment work as shown in FIG. 4 during mass production. In FIG. 1, when using an A / D converter 3 having a large number of bits,
The AGC circuit (amplifier circuit) in the S / AGC circuit 2 can be deleted.

[0014]

As described above in detail, the solid-state imaging device according to the present invention includes a solid-state imaging device (CCD), a sample hold / amplifier circuit (CDS / AGC circuit), and a nonvolatile memory device on a first substrate. A / D converter, digital signal processing circuit, CCD drive circuit, timing generation circuit,
A microcomputer is mounted on a second substrate, and the photoelectric conversion characteristics of the solid-state imaging device and the sample hold / amplifier circuit are previously written as digital data in a nonvolatile memory element of the first substrate. The second substrate is assembled, the digital data written in the nonvolatile memory element is read out by the microcomputer, and the digital signal processing circuit is initialized, so that the adjustment work at the time of mass production can be simplified. As a result, the efficiency of the manufacturing operation is improved. Furthermore, the collection of basic data (photoelectric conversion characteristics of the circuit of the first substrate) can be performed in the state of a small substrate, so that it is easy to mechanize. By doing so, adjustment is not required, and serviceability is improved. In addition, if the device is provided with an interface between the microcomputer and the outside, basic data such as the spectral characteristics and gradation characteristics of the solid-state imaging device can be used by an external image processing device, and correction and conversion of image colors can be performed. There is also a feature that such work can be easily performed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an embodiment of a solid-state imaging device according to the present invention.

FIG. 2 is a diagram for explaining a data writing operation in the solid-state imaging device of the present invention.

FIG. 3 is a block diagram illustrating an example of a conventional solid-state imaging device.

FIG. 4 is a diagram illustrating an adjustment operation of a conventional solid-state imaging device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Solid-state image sensor (CCD) 2 CDS / AGC circuit (sample hold / amplification circuit) 3 A / D converter 4 Digital signal processing circuit 5a, 5b D / A converter 6 CCD drive circuit 7 Timing generation circuit 8 Microcomputer 9 Non-volatile memory device A, B substrate

Claims (1)

(57) [Claims] 1. A solid-state imaging device for photoelectrically converting a subject image and outputting the same, and a sample-and-hold device for extracting an image signal component from a signal output from the solid-state imaging device and amplifying and outputting the image signal component.
An amplifier circuit; an A / D converter that converts an image signal output from the sample hold / amplifier circuit into a digital image signal and outputs the digital image signal; and a signal for the digital image signal output from the A / D converter. A digital signal processing circuit that performs processing, a digital drive circuit that drives the solid-state imaging device, the sample-hold / amplifier circuit, the A / D converter,
A solid-state imaging device comprising: a digital signal processing circuit; a timing generation circuit that supplies a timing signal necessary for the digital drive circuit; and a microcomputer that supplies a control signal required for the digital signal processing circuit. And a non-volatile memory element for writing photoelectric conversion characteristics by the sample hold / amplifier circuit as digital data, wherein the solid-state imaging device, the sample hold / amplifier circuit,
Mounting the nonvolatile memory element on a first substrate, mounting the A / D converter, the digital signal processing circuit, the digital drive circuit, the timing generation circuit, and the microcomputer on a second substrate; After assembling the first substrate and the second substrate, the microcomputer reads the digital data written in the nonvolatile memory element and initializes the digital signal processing circuit. Solid-state imaging device.