JPH11308532A - Multi-element sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain miniaturization, low noise, low power consumption and high speed processing for the sensor. SOLUTION: The sensor is provided with a electromagnetic wave detection means 19 that converts an electromagnetic wave into an analog signal depending on its strength and with an A/D converter means 20 that converts the analog signal converted by the electromagnetic wave detection means 19 into a digital signal. Then one-chip or multi-chip module processing unifies the circuit components from the electromagnetic wave detection means 19 to the A/D converter means 20. Since pluralities of packages in a conventional sensor are decreased into one package, miniaturization of the sensor is attained. Moreover, wiring interconnecting the conventional packages having been required for the conventional sensor is not required, low noise configuration is attained. Since it is not required to amplify analog signals with a high amplification factor as that of the conventional sensor, low power consumption is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a multi-element sensor device such as a CCD image pickup device.

[0002]

2. Description of the Related Art As shown in FIG. 3, a conventional CCD image pickup device comprises a photo array 21, a CCD (charge-coupled device) 2, and the like.
2. It comprises a clamp circuit 23, an output amplifier 24, an A / D converter 25 and the like. Photo array 21
The CCD 22 is formed on one chip. The photo array 21 and the CCD 22, the clamp circuit 23, the output amplifier 24, and the A / D converter 25 are housed in separate packages, and are connected to each other by a lead wire or the like.

[0003]

However, the conventional CCD image pickup apparatus has the following problems.

[0004] Analog processing circuits such as the clamp circuit 23, the output amplifier 24, and the A / D converter 25 housed in separate packages must be arranged near the photo array 21 and the CCD 22 in order to minimize superposition of noise. Therefore, the photo array 21 and C
Since many packages are densely packed in the vicinity of the CD 22, the head of the CCD image pickup device cannot be miniaturized.

[0005] These analog processing circuits are arranged in the vicinity of the photoarray 21 and the CCD 22, but must be arranged outside the package of the photoarray 21 and the CCD 22 as a matter of course. For this reason, noise from wirings connecting the packages has been superimposed to some extent.

[0006] In order to reduce this noise and improve the S / N ratio of the A / D converter 25, the analog output signal of the CCD 22 is greatly amplified by the output amplifier 24. Because of the power required for this amplification, it has been difficult to reduce power consumption.

[0007] Various corrections such as dark current are collectively processed in the final stage of signal processing after digitizing an analog signal. Therefore, high-speed processing was difficult due to a heavy burden on the subsequent stage.

[0008]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to achieve downsizing, low noise, low power consumption, high speed processing, and the like.
It is to provide a multi-element sensor device.

[0009]

A multi-element sensor device according to the present invention comprises: an electromagnetic wave detecting means for converting an electromagnetic wave into an analog signal according to its intensity; and a digital signal for converting the analog signal converted by the electromagnetic wave detecting means. A to convert to signal
/ D conversion means. The feature of the present invention resides in that the components from the electromagnetic wave detection means to the A / D conversion means are integrated. These integrations are, for example, 1
It is realized by making into chips or multi-chip modules.

[0010] By integrating the electromagnetic wave detecting means to the A / D converting means, a plurality of conventional packages are reduced to a single package, so that downsizing is achieved. In addition, since wiring for connecting the packages, which is conventionally required, is not required, noise reduction is achieved. This lower noise eliminates the need to amplify the analog signal as much as in the past, thus achieving lower power consumption.

Further, the present invention may further include a temperature detecting means integrated with the electromagnetic wave detecting means and detecting a temperature of the electromagnetic wave detecting means. The integration of the temperature detecting means with the electromagnetic wave detecting means is realized by forming one chip or bonding a plurality of chips together. Furthermore,
The present invention may be provided with analog signal correction means for correcting an analog signal based on the temperature detected by the temperature detection means.

The temperature of the electromagnetic wave detecting means is directly and accurately detected by the temperature detecting means integrated with the electromagnetic wave detecting means. In addition, since the analog signal is corrected based on the temperature, the analog signal is corrected before digitization, so that the burden on the subsequent stage is reduced, thereby achieving high-speed processing.

[0013]

FIG. 1 is a block diagram showing an embodiment of a multi-element sensor device according to the present invention. Less than,
Description will be made based on this drawing.

The multi-element sensor device of the present embodiment has a CC
A D imaging apparatus, comprising: an electromagnetic wave detecting unit 19 that converts an electromagnetic wave into an analog signal according to its intensity; and an A / D converting unit 20 that further converts the analog signal converted by the electromagnetic wave detecting unit 19 into a digital signal. It is a thing. Then, the components from the electromagnetic wave detection means 19 to the A / D conversion means 20 are integrated by one chip or multichip module. Further, the temperature sensor 19 as the temperature detecting means for detecting the temperature of the electromagnetic wave detecting means 19 is integrated with the electromagnetic wave detecting means 19 by integrating the chips into one chip or by bonding a plurality of chips to each other. The temperature sensor 19
It can be incorporated in one chip as a polysilicon layer or a diffusion layer.

The electromagnetic wave detecting means 19 includes the photo array 1,
It comprises a CCD 2, a reset circuit 3, an output amplifier 4, a delay circuit 5, a sample and hold circuit 6, and the like. The A / D converter 20 includes comparators 7-1 to 7-
512, an encoder 8, a D / A converter 9, and the like. Further, the electromagnetic wave detecting means 19 and the A / D
Outside the package of the conversion means 20, a dark current correction value generation circuit 10, a dark current coefficient memory 11, a pixel counter 1
2. The analog signal correction means and the like are constituted by the dark current correction circuit 13, the configuration data conversion circuit 14, the buffer circuit 15, the data processing circuit 16, the CCD drive circuit 17, the correction operation setting circuit 18, and the like.

FIG. 2 is a time chart showing a part of the operation of the multi-element sensor device of FIG. Hereinafter, the operation of the multi-element sensor device according to the present embodiment will be described with reference to FIGS.

The electromagnetic waves are converted by the photo array 1 into electric charges proportional to the intensity. The charges are transferred to the CCD 2 by a transfer clock, and are sequentially transferred by a drive signal. The reset circuit 3 clears the remaining charge of the previous pixel with the reset signal φR, determines the reference voltage level, and outputs the signal level from the output amplifier 4. The reference level of the output signal from the output amplifier 4 is first held by the sample and hold circuit 6. Based on this reference level, the D / A converter 9 sets the maximum voltage level of the signal level or an arbitrarily set maximum voltage level. Voltages obtained by dividing the maximum voltage level by 29 uniform resistance values are generated, and the respective voltages and signal levels are compared by comparators 7-1 to 7-512. 'Or' L 'if low. By encoding these signals by the encoder 8,
A digital value corresponding to the intensity of the electromagnetic wave is obtained. When the signal level becomes equal to or higher than the voltage set as the maximum voltage, the overflow detection signal becomes active, and when the gain is automatically set, the voltage is reset to the next higher voltage.
However, when changing from the next frame, it is switched by the start pixel signal.

Before starting the imaging operation or at the manufacturing stage, in order to correct the dark current, a digitized signal is stored as data obtained by normalizing the dark current value. A dark current correction value generation circuit 10 having a coefficient based on temperature, gain, and the like finally generates a digital value (correction data) corresponding to the dark current, and a dark current correction circuit 13 subtracts the correction data from the signal. By doing so, the offset of the dark current is subtracted. When acquiring the dark current correction data, the dark current correction data setting enable signal of the dark current correction circuit 13 and the dark current coefficient memory 11 is activated. Further, it is also possible to transfer the temperature data to the signal line at a timing that is not an effective pixel.

The signal subjected to the dark current correction is converted by a correction data conversion circuit 14 in accordance with sensitivity correction data or non-linear data programmed in advance, and the buffer circuit 1
At 5, a signal is transmitted. Also in this case, it is possible to switch to a mode in which the correction value is recorded by the correction data enable signal.

The image data is processed according to the purpose in the data processing. In addition, a function of generating and outputting correction data and gain data is provided. The timing of these signals is generated by the CCD drive circuit 17 and used for overall control. The correction operation setting circuit 18 controls the execution of initialization or programming of dark current correction.

The temperature sensor 19 is provided in the photo array 1.
And the temperature data of the CCD 2 can be directly grasped. This temperature data is digitized and does not require an analog processing circuit. Therefore, the dark current correction value generation circuit 10 can output a corresponding dark current correction value by logic calculation. It is to be noted that there is a possibility that these correction values are different from each other, so when accuracy is required, individual data is input. If accuracy is not required, a conversion table of a correction value having a temperature function and a gain function is input for each lot or each product. If it is desired to correct even individual pixels, a dark current coefficient memory 1 storing the dark current coefficient of the pixel corresponding to the pixel counter value is stored.
From 1, the coefficient is output to the dark current correction value generation circuit 10.

Since the dark current coefficient of this pixel may be different between the individual photo array 1 and the CCD 2, the dark current is measured by a high temperature test to obtain the temperature coefficient in order to make the coefficient correspond exactly. Sometimes. For this purpose, the dark current value from the encoder 8 is stored in the dark current coefficient memory 11.
The data is directly input to the memory, and the data setting (data acquisition) and the output mode of the dark current correction data are switched by the dark current correction data setting enable signal. When switching the gain, the dark current correction value generation circuit 10 takes in the gain value and multiplies the dark current correction value by a gain. Although the gain data is also input to the D / A converter 9, the timing for setting the gain can be switched by the gain data setting enable signal. When switching automatically, switching is performed instantaneously by the overflow detection signal from the encoder 8. To lower or fix the gain, the data processing circuit 1
The gain data is set by obtaining an average value at 6 or the like. In the case where the gain has several stages by automatic gain switching, a means for outputting the value together with the data may be used.

The data processing speed varies depending on the number of pixels, the frame processing speed, and the intensity of electromagnetic waves. For general camera applications,
The rate is 30 frames per second, but is not limited to the case where it is used for industrial use such as a production line. Therefore, the processing time of one pixel is changed by a delay adjustment signal so that the delay time can be changed because the timing of multiplying S / H is delayed from the reset signal φR. I do.

When the distance between the acquired data subjected to the respective corrections and the data processing circuit 16 is large, the buffer circuit 15 is inserted so as to act as a line driver, thereby making it possible to avoid restrictions on the distance. If it is desired to minimize the head portion that converts electromagnetic waves into electric signals, the pixel counter 12 and the like before the dark current correction value generation circuit 10 can be separated from the encoder 8. However, since the data is exchanged digitally even with this separation, the image quality is not impaired.

The multi-element sensor device according to the present invention can be applied to any sensor from ultraviolet rays to far infrared rays as long as it is a conversion element for converting electromagnetic waves into electricity. For example, in the case of a CCD sensor in the near infrared region, it is conceivable that the photo array and the CCD have heat because the subject has heat. As described above, the present invention is considered to be highly effective in that temperature correction can be performed particularly in data acquisition where the temperature environment is severe. When the radiant energy of the subject is small, the photographing time may be lengthened. In this case, the level of the dark current becomes quite anxious,
In particular, it can be said that the correction method according to the present invention is very effective.
As an example where the imaging time is long, there is an astronomical telescope using a CCD camera. In this case, the photo array and the CCD are cooled as required, but the temperature data at this time is important. Even in such a case,
The present invention has a configuration in which accurate temperature data can be obtained.

[0026]

According to the multi-element sensor device of the present invention, since the electromagnetic wave detecting means and the A / D converting means are integrated, the conventional plural packages become one package. Miniaturization can be achieved. In addition, since wiring for connecting each package, which is conventionally required, is not required, low noise can be achieved. This reduction in noise eliminates the need to amplify the analog signal as much as in the past, so that low power consumption can also be achieved.

The temperature of the electromagnetic wave detecting means can be detected very accurately by the temperature detecting means integrated with the electromagnetic wave detecting means. Further, by correcting the analog signal based on this temperature, the analog signal can be corrected before digitization, so that high-speed processing can be achieved.

As described above, according to the present invention, since the analog signal of the output amplifier is immediately converted into a digital signal, the clamping process or the signal amplification performed in the subsequent stage is performed simultaneously in the digitizing process as in the related art. In addition, it is possible to eliminate superimposed noise in analog processing, and it is possible to eliminate the need for an analog circuit. In addition, since the dark current can be corrected in the head,
When accurate measurement and high-speed processing are required, or when data compression is performed, the time can be particularly effectively reduced.
This correction can be performed by programmably recording a dark current correction value, setting a gain, performing non-linear processing, and the like, before imaging.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a multi-element sensor device according to the present invention.

FIG. 2 is a time chart showing a part of the operation of the multi-element sensor device of FIG.

FIG. 3 is a block diagram showing a conventional multi-element sensor device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoarray 2 CCD 3 Reset circuit 4 Output circuit 5 Delay circuit 6 Sample hold circuit 7-1 to 7-512 Comparator 8 Encoder 9 D / A converter 10 Dark current correction value generation circuit 11 Dark current coefficient memory 12 Pixel counter 13 Dark Current correction circuit 14 Configuration data conversion circuit 15 Buffer circuit 16 Data processing circuit 17 CCD drive circuit 18 Correction operation setting circuit 19 Electromagnetic wave detection means 20 A / D conversion means

Claims (7)

[Claims] An electromagnetic wave detecting means for converting an electromagnetic wave into an analog signal according to its intensity, and an A / D converting means for further converting the analog signal converted by the electromagnetic wave detecting means into a digital signal. A multi-element sensor device, wherein the electromagnetic wave detection means and the A / D conversion means are integrated. 2. The multi-element sensor device according to claim 1, wherein the part from the electromagnetic wave detecting means to the A / D converting means is integrated by one chip. 3. The multi-element sensor device according to claim 1, wherein the part from the electromagnetic wave detection means to the A / D conversion means is integrated by a multi-chip module. 4. The multi-element sensor device according to claim 1, further comprising temperature detecting means integrated with said electromagnetic wave detecting means and detecting a temperature of said electromagnetic wave detecting means. 5. The multi-element sensor device according to claim 4, wherein said temperature detecting means is integrated with said electromagnetic wave detecting means by one chip. 6. The multi-element sensor device according to claim 4, wherein said temperature detecting means is integrated with said electromagnetic wave detecting means by bonding a plurality of chips together. 7. The multi-element sensor device according to claim 4, further comprising an analog signal correcting unit for correcting the analog signal based on the temperature detected by the temperature detecting unit.