JPH0368284A - Check device for solid-state image pickup element - Google Patents

Abstract

PURPOSE:To decrease number of times for averaging picture data and to reduce the check time by sharing the improvement of the S/N of the picture element with the averaging of a semiconductor memory and the averaging of binary picture element data. CONSTITUTION:A picture element of a solid-state image pickup element P being an object to be checked is photoelectric-converted by a drive circuit 7, inputted to an A/D converter 1 in the order of the arrangement of picture elements and a picture data converted into a digital signal is stored in a 1st semiconductor memory 2 corresponding to the picture element arrangement. The storage is implemented by n-times photoelectric conversion outputs as to a same picture element. The picture element data stored in the semiconductor 2 is transferred to an averaging circuit 3, where two picture element data opposite in the vertical direction are averaged.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to an inspection apparatus for a solid-state image sensor using photoelectric conversion elements as pixels.

(Prior art) Fig. 3 shows the configuration of a conventional solid-state image sensor inspection apparatus together with an object to be inspected, where P is the solid-state image sensor of the object to be inspected, 31 is an A/D converter, and 32 is an A/D converter. semiconductor memory, 33
34 is a data processing circuit, 34 is an operation procedure controller, and 35 is a drive circuit.

With this configuration, pixel signals photoelectrically converted by the drive circuit 35 are sequentially output from the solid-state image sensor P of the object to be inspected according to the pixel arrangement. The pixel signals are sequentially A/
The D converter 31 performs A/D conversion on the outputs of all pixels, converting them into digital signals of, for example, 10 bits, and storing the same pixel n times ( (n is any positive integer) The average value of the photoelectrically converted pixel signals is stored.

Next, the above n pixel data stored in the semiconductor memory 32 is sequentially transferred to the data processing circuit 33, where it is subjected to arithmetic processing and a pixel defect determination is performed, and the quality of the solid-state image sensor P of the object to be inspected is determined. be done.

The operation procedure controller 34 controls starting, stopping, etc. of the drive circuit 35 and the data processing circuit 33.

Conventionally, the solid-state image sensor P has been tested in one or more ways.

(Problem to be Solved by the Invention) However, the above-mentioned conventional inspection apparatus for solid-state image sensors has the disadvantage that the inspection time is long because the pixel data is read out from the same pixel n times and stored in the semiconductor memory 32 after being averaged. There is. The above averaging is intended to improve the pixel signal-to-noise ratio and make the judgment more accurate.If the averaging is not performed, the defective signal output of the defective pixel will be masked by noise, making it difficult to judge whether it is good or bad. become. Furthermore, if the required pixel signal-to-noise ratio cannot be obtained, the number of averaging operations must be further increased, resulting in even more testing time.

In view of the above-mentioned conventional problems, the present invention provides a solid-state image sensor that reduces the number of averaging times of stored pixel data and shortens inspection time while maintaining the same pixel signal-to-noise ratio as the conventional one. The purpose is to provide inspection equipment for

(Means for Solving the Problems) The present invention achieves the above object by using an A/D converter that converts the photoelectric conversion output of the pixels constituting the solid-state image sensor of the object to be inspected into a digital signal, and the same pixel. a first semiconductor memory that sequentially stores, as pixel data, the output obtained by A/D converting each of the photoelectric conversion outputs n times (n is any positive integer) (n is any positive integer); The above pixel data is divided by ji' + J in the vertical direction of the array.
an averaging circuit that averages each pixel; a second semiconductor memory that stores pixel data output from the averaging circuit; the stored pixel data is read out and subjected to arithmetic processing to determine whether or not there is a defect in the pixel. This is achieved by providing a data processing circuit.

(Function) According to the present invention, the conventional improvement in pixel signal-to-noise ratio achieved by averaging pixel data n times can be divided between the semiconductor memory and the averaging circuit, thereby reducing the number of averaging operations in the semiconductor memory. , thus reducing inspection time. In other words, the output obtained by averaging the outputs of two pixels facing each other in the vertical direction corresponds to two averages in the semiconductor memory, and since the semiconductor memory and the averaging circuit are connected in series,
Even if the averaging circuit is n/2 in semiconductor memory, the pixel signal-to-noise ratio is n/2 x 2, which is n.
Therefore, the inspection time can be shortened by the reduction in the number of times of averaging.

(Example> The present invention will be explained in detail below using the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.
P is a solid-state image sensor which is the object to be inspected, 1 is an A/D converter,
2 is a first semiconductor memory, 3 is an averaging circuit, 4 is a second semiconductor memory, 5 is a data processing circuit, 6 is an operation procedure controller, and 7 is a drive circuit.

In the above configuration, the solid-state image sensor P of the object to be inspected
The pixels are photoelectrically converted by the drive circuit 7.

Output signals are input to the A/D converter 1 in the order of the pixel arrangement, and the pixel data converted into, for example, a 10-bit digital signal is sent to the first semiconductor in accordance with the pixel arrangement of the solid-state image sensor of the object to be inspected. Stored in memory 2. This storage is performed for n photoelectric conversion outputs for the same pixel.

Next, the above pixel data stored in the semiconductor memory 2 is sequentially transferred to the averaging circuit 3, where two vertically opposing pixel data are averaged.

FIG. 2 is a diagram schematically showing the relationship between pixels and photoelectric conversion outputs to explain the averaging.

21 to 25 are pixel columns, and the photoelectric conversion output signal of each pixel is taken out as output signals 26 to 29 as the average output of two pixels facing each other in the vertical direction. The average value of the outputs of the pixels in columns 21 and 22, and the output signal 27 of two opposing pixels in pixel columns 22 and 23, respectively, is output and stored in the semiconductor memory 4.

In this way, for example, if the pixel 22' is a defective pixel, the defective output will appear in the output signals 26 and 27, and the semiconductor memory 4 will store the average pixel data of the vertically opposing pixels. Become.

That is, as described above, the output data of the averaging circuit 3 is stored in the second semiconductor memory 4, and the stored data is sequentially transferred to the data processing circuit 5, where it is subjected to arithmetic processing and the quality of the pixel is determined. , the quality of the solid-state image sensor P is determined. Note that the 5-operation procedure controller 6 controls the operation procedure of the entire apparatus, and controls starting, stopping, etc. of the drive circuit 7.

As explained above, the present invention improves the pixel signal-to-noise ratio by dividing the burden between the semiconductor memory IJ 2 and the averaging circuit 3 in order to facilitate pixel inspection.
Even if the number of times of averaging in the semiconductor memory 2 is reduced, a pixel signal-to-noise ratio similar to the conventional one can be obtained, and therefore the time required for inspection can be shortened.

(Effects of the Invention) As is clear from the above explanation, the present invention improves the pixel signal-to-noise ratio by dividing it into averaging in the semiconductor memory and averaging data of two pixels facing each other in the vertical direction. By reducing the number of times of averaging, it is possible to maintain the same pixel signal-to-noise ratio as in the prior art. That is, the present invention can reduce the number of times pixel data stored in a semiconductor memory is averaged, and has the effect of shortening inspection time.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a diagram explaining pixels of a solid-state image sensor and their output signals, and FIG. 3 is a block diagram showing a conventional inspection apparatus for a solid-state image sensor. It is a diagram. 1... A/D converter, 2... First semiconductor memory, 3... Averaging circuit, 4... Second semiconductor memory, 5... Data processing circuit, 6... Operation procedure controller, 7... Drive circuit, P... Solid-state image sensor.

Claims (1)

[Claims] An A/D converter that converts the photoelectric conversion output of the pixels constituting the solid-state image sensor of the object to be inspected into a digital signal, and each of the photoelectric conversion outputs n times (n is any positive integer) for the same pixel. A first semiconductor memory sequentially stores the A/D converted and averaged output as pixel data in the same way as the pixel array of the solid-state image sensor of the object to be inspected, and the sequentially stored pixel data is stored in the array as pixel data. An averaging circuit that averages two pixels facing each other in the vertical direction, a second semiconductor memory that stores pixel data output from the averaging circuit, and the stored pixel data is read out and processed to calculate the value of the pixel. 1. An inspection device for a solid-state image sensor, comprising a data processing circuit for determining the presence or absence of a defect.