JPS6028190B2 - solid state imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides time delay integral
The present invention relates to a new configuration of an imaging device, particularly an infrared imaging device, using a CCD (abbreviation: TDI) structure.

A linear array type infrared imaging device generally has a large number of infrared receiving elements arranged in a row, and the signals that have been optically converted by the infrared receiving elements are guided to each bit of a CCD and output as a time-series image signal. be.

In this type of moat imaging device, each light receiving element has an IJ-current, etc., resulting in a poor signal-to-noise ratio (S/N ratio) of the element itself, and also due to non-uniformity of characteristics of each element. It is difficult to reproduce good images.

Therefore, in order to eliminate the above drawbacks, improve the S/N ratio, improve the mounting density of infrared light receiving elements, and improve the spatial resolution, we have developed an array in which light receiving elements are arranged in rows and columns. The optical image is scanned, and the output signals from each light-receiving element on the row induced with a time difference are inputted to each bit of an integrator, for example, a CCD, which performs time-delay integration in synchronization with the scanning of the optical image. A device has been proposed in which the image signal is integrated to improve the S/N ratio of the image signal. In this method, if the signal obtained from one light-receiving element is S and the noise is N, then if the number of light-receiving elements in the column direction is n, the integral signal is nS and the noise signal is non-nN, so the resulting signal is The noise ratio will be improved by a factor of two. Therefore, the output from the integrators in each column is transferred to another CCD.
By connecting to the infrared rays and extracting time-series image signals and inputting them to a display device, it becomes possible to display an infrared image in a good form. However, in the above-mentioned time-delay-integration type linear array infrared imaging device, each detection element is required to be arranged as densely as possible in order to increase the spatial resolution of the device, but on the other hand, the time-delay-integration CCD requires a relatively large area. Since one input section is required for each light-receiving element, wiring and layout settings for the CCD and detection element become a major problem.Furthermore, the pitch of the infrared elements in the linear array needs to be approximately 100m as a typical value. However, if the bit length of a time-series signal processing CCD is matched to the pitch of this light receiving element, the problem arises that the CCD is too long to be transferred at a high clock frequency, making high-speed signal processing impossible.

In addition, the output signal from each infrared receiving element usually comes out in the form of a DC component as a background signal, which makes up most of the output signal, in addition to the signal fluctuation component for identifying the object to be imaged. In order to process the signal, CC is a signal accumulation area that has an overflow gate that extracts only the variation of the target signal and also has the function of removing unnecessary DC signal components.
It is necessary to provide the functional elements between the signal input section of D and the light receiving element, and in this respect as well, the arrangement of each functional element becomes complicated and a large space is required. The present invention has been made in view of the above-mentioned points, and includes a light receiving element array arranged in rows and columns with the direction perpendicular to the optical scanning direction, and optical signals in each column parallel to the optical scanning direction. In a solid-state imaging device comprising a CCD that performs time delay integration and a CCD that inputs the CCD output that integrates the signal for each column and outputs it as a time series signal in the row direction, light is received in each column parallel to the optical scanning direction. Connecting lines connecting the elements and time delay integrating CCDs are alternately led out on both sides of the light receiving element array in the column direction, and the time delay integrating CCDs are arranged corresponding to the leading lines, and corresponding to the alternate columns. C for outputting two time series signals from each time delay integral CCD
It is characterized in that it is connected to a CD respectively.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of an embodiment of the field imaging device of the present invention, particularly an infrared imaging device. In the figure, 1 and 0 indicate an infrared light receiving element array, which is an optical image. In other words, n light-receiving elements are arranged in the column direction parallel to the scanning direction x indicated by the signal arrow, and m light-receiving elements are arranged in the row direction orthogonal to the signal scanning direction. The rice bran imager is configured to scan an optical image in parallel to the row direction on the light receiving element array 10, and the light receiving element in the first row scans the same optical image detected at time t2 again. The light receiving elements in the second row detect this signal, and the light receiving elements in the third row detect this signal at a certain time.

In this way, the light receiving scan is repeated up to the n-th element while delaying the time. On the other hand, a photoelectric conversion signal detected by these light-receiving elements is provided corresponding to each row with a function of deriving changes in the received light signal through derivation lines a, b, c, etc. and excluding DC signal components such as background signals. t in the signal accumulation area 11
,, t2, . . . are derived at timings Tn.

Next, the change signal from this signal accumulation area is applied to the first bit, third bit, and
...At the (phantom-1)th bit, time t,,t2,...
The photoelectric conversion signals introduced through the input gate 13 at timing tn and detected by the light receiving elements of the first to nth rows are time-integrated. For time delay integration, the clock frequency of the CD is synchronized with the frequency at which the photodetectors in each row sequentially receive light. This time-delay integrated signal, that is, nS, is taken out from the output detection section 14, and the signal is output in time series.
The signal is inputted to the CCD 15 of the system and transferred and derived in the direction of arrow A. The time delay integrators 12 are provided correspondingly from the first column to the m-th column, and output signals of the 1st to nth outputs P, ~Pm of the time delay integral in time series, respectively. This signal is simultaneously introduced into each corresponding bit of the CCD 15 to be output, and this signal is sequentially derived from the output terminals 16 and 17 to be taken out as an image signal. The delay integrator 12 is configured to take out the signal detected by each light receiving element, and time series signal output CCDs 15 are provided on the left and right sides of the light receiving element array 10 corresponding to each time delay integrator 12. As described above, this makes it possible to simplify wiring between elements and achieve high-speed operation.

By providing the signal processing system on the left and right sides of the light-receiving element array in this way, the complexity of wiring can be eliminated, and the number of bits of the time-series signal output CCD 15 can be reduced to 1/2 bit compared to the conventional one. Yield can also be improved. Note that 19 indicates an input signal processing section from the time delay integration CCD 12 to the time series signal output CCD 15. FIG. 2 shows a specific configuration of the infrared light receiving element array shown in FIG.

In the figure, the same parts as those in FIG. 1 are given the same reference numerals and explained. In Fig. 2, a is a light-receiving element forming substrate 2 made of a multi-component semiconductor such as mercury, dTe, etc.
FIG. 2 is a diagram showing a section of a light-receiving element array including a plurality of light-receiving elements arranged in n columns and m rows. The infrared receiving element generally has a light-receiving area of about 50 square meters by 50 square meters, and the pitch P of each element is 100 square meters. The light receiving section Se of such a light receiving element array is a time delay integrating CCD 12 constructed on a silicon substrate Si as shown in FIG. 2b.
The indium ln pad part of the wiring connected to the input diode of the signal storage part 11 configured at the input part of
The wiring between each element is simplified by connecting through a conductor such as n. Note that the dotted lines in the multi-component semiconductor substrate 20 in figure b indicate P-n junctions, 21 is an ln pad, and 22 is an ln pad.
Showing solder. Note that figure c shows an example of a wiring pattern formed on a silicon substrate Si, 23 shows an ln pad part formed at a position corresponding to a light receiving element, and other hatched parts show wiring made of aluminum or the like. In this wiring, the signal detection lines from the light-receiving element one row above in the column direction are led out to the left and right for each column, as shown by R and L in the figure, to prevent a reduction in wiring density and complication. This is how it was done.

As described above, by configuring a linear array type infrared imaging device, it is possible to easily configure a TDI structure, improve the S/N ratio, and increase the speed of signal processing. It can also be easily realized in a device, and furthermore, the configuration of the device can be simplified.

Note that the gist of the present invention can be applied not only to infrared imaging devices but also to semiconductor imaging devices for visible light, and is highly effective.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an embodiment of the solid-state imaging device according to the present invention, and FIG. 2 is a diagram illustrating the configuration of the light-receiving element array section of FIG. 1. 10... Light receiving element array, 11... Signal accumulation region,
12... Time delay integrator, 13... Input gate, 1
4... Output detection unit, 15... Time series signal output CCD
, 16, 17...signal output terminal, 19...input signal processing section,
20...Multiple semiconductor substrate, 21...Indium pad, 22...Indium solder, 23...Indium pad. Diagram 2

Claims (1)

[Claims] 1. An array of light receiving elements arranged in a matrix with the row direction perpendicular to the optical scanning direction, a CCD that performs time delay integration of optical signals in each column parallel to the optical scanning direction, and a signal for each column. Input the integrated CCD output,
It has a CCD that outputs a time series signal in the row direction, and includes light receiving elements in each column parallel to the optical scanning direction and a time delay integral C.
Connection lines connecting the CDs are alternately led out on both sides of the light receiving element array in the column direction, and the time delay integration CCDs are arranged corresponding to the lead-out lines, and each time delay integration CCD corresponding to the alternate columns is provided. C for outputting CCD output as two time series signals
A solid-state imaging device characterized in that it is connected to a CD.