JPS61140284A - Solid-state image pickup device - Google Patents

Abstract

PURPOSE:To increase the drive speed of one line by using output 1 bit of a drive circuit to drive plural picture elements and reading an optical signal from plural series of signal lines. CONSTITUTION:The driving speed of one line is increased by using output 1 bit of the drive circuit to drive plural picture elements 105-110. The one line drive speed is increased by N times in comparison with one picture element drive by one bit output of the drive circuit, where N is picture element number driven by one bit output of the drive circuit. In this case, when a read signal line is one series, since the optical signal read from N picture elements is read overlappingly, N systems of signal lines are provided and it is required to read them separately. Further, in this case, since the bit number of the drive circuit is enough to be 1/N of the picture element number, the increase in the chip area is relaxed even with high resolution scheme. Since it is possible to extract the optical signal in time division from picture elements driven at the same time by inserting an analog switch respectively to N signal lines, it is not required for external signal processing.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to solid-state imaging devices.

[Conventional technology]

In the conventional solid-state imaging device, one pixel is driven by one beat I of the output of the drive circuit, and the readout signal line is also one.
It was a series. In the figure, 201 is a thin film transistor (hereinafter referred to as TPT) drive circuit, 202 to 205 are pixels, 206 to 209 are output terminals of the drive circuit 201, and 21G is a read signal line.

Figure 1E3 shows the equivalent circuit of one pixel. In the same figure, 30
1 is an analog switch using a TFT, 502 is a photoelectric conversion element based on a photoreceptor thin film,! 5O3t'i positive 1 source, 304
is a connection terminal to the read signal line, and the potential here is pseudo-grounded to the negative power supply. Reference numeral 305 is an input terminal for a signal that controls opening and closing of the analog switch 301, and is connected to an output terminal of the drive circuit. Hereinafter, it is assumed that when the potential of 305 is high, the analog switch 301 is conductive.

FIG. 4 shows the drive voltage waveform of the 1E2 solid-state imaging device. In the same figure, 401, 402. 403 are the output terminals 206. of the drive circuit 201, respectively. 207.
This is a voltage waveform applied to 208. Time tl to tt
l tt~1,,1. 20 pixels each from t4 to t4
2. 205. 204 is driven.

[Problems that the invention aims to solve]

Figure 11E2 In the conventional solid-state photographic device, l[movement circuit 2
At the operating speed of 01, the reading speed of the signal was limited. Especially when polysilicon TFTI is used in a dynamic circuit,
Since the practical upper limit frequency of the driving circuit is 500 KH2, it takes am
It is limited to sec centrality of 5°.Furthermore, it requires the same number of stages of drive circuits hζ as the number of pixels, which is disadvantageous for achieving high resolution. 5. In the case of a solid-state imaging device with a resolution of 16 pixels, the pixel width is approximately 60tsn, but since the drive circuit must be inserted in this width, the solid-state imaging device chip size is approximately 60tsn. This is because the stripes become larger in the direction perpendicular to the array. When polysilicon TPT is used for the circuit, the driving ability is inferior to that of MOS trunk transistors, etc., and it is necessary to increase the element size. ), resulting in a significant increase in chip size.

An object of the present invention is to solve the above-mentioned problems and realize a high-speed, high-resolution, low-cost solid-state imaging device.

[Means for solving problems]

The solid-state imaging device of the present invention is characterized in that a plurality of pixels are driven by one bit output from a drive circuit, and optical signals are read out from a plurality of signal lines.

[Effect]

According to the above configuration of the present invention, it is possible to increase the driving speed of one line rather than moving a plurality of pixels with one bit of output from the driving circuit. When the number of pixels driven by one drive circuit is N, the driving speed for one line is N times higher than when driving one pixel by one drive circuit. In this case, if there is one series of readout signal lines, the optical signals read out from N pixels will be read out overlappingly, so it is necessary to provide N series of signal lines and read them separately.

In this case, the number of bits of the drive circuit is 17 of the number of pixels.
Since only N is required, even if the resolution is increased, the increase in chip area is minimized.

By inserting seven analog switches in Mayu and N Shinyaren, it becomes possible to extract optical signals from pixels that are ringing at the same time in a time-divided manner, eliminating the need for external signal processing. disappears.

Therefore, by using the present invention, a high-performance, low-cost solid-state imaging device can be realized.

〔Example〕

FIG. 91 shows an embodiment of the present invention. In the same figure, there are 101 drive circuits, 102 to 104 are output terminals of the drive circuit 101, 105 to 11G are pixels, 111 and 112 are two-sequence input/output signal lines, and the figure shows 1-bit output of the drive circuit. This is an example in which two pixels are driven by .

FIG. 5 also shows an embodiment of the present invention, and the same symbols as in FIG. 1 represent the same elements as in FIG. 1.

501 to 510 are pixels, and 511 to 513 are read signal lines. The figure shows the output of the @ moving circuit is 1 B, and 3 at G.
This is an example of driving pixels.

Figure t$6 is also an embodiment of the present invention, in which the zWi element is set to I[by one bit of the output of the drive circuit], and an analog switch is inserted in the readout register. In the figure, 601 is a drive circuit, 602 to 605 are output terminals of the drive circuit 601, 606 to 613 are pixels, 614 and 615 are two-sequence input/output signal lines, and 616 and 617 are analog TFTs. Switches 618 and 619 are signal input terminals that control the opening and closing of analog switches 616 and 617, respectively, and 620 is a signal input terminal for controlling the opening and closing of analog switches 616 and 617.
The terminal No. 7 is connected to the terminal 7 and serves as a signal readout terminal to the outside.

FIG. 7 is an example of the drive voltage waveform of the sixth repositionable body imaging device, with 70
1, 702, and 703 are drive circuits 601, respectively.
output terminal 602. 60! l, the voltage waveform applied to 604, 704. 705 is the opening/closing of analog switches 616 and 617, and the control signal input terminal 61
This is the voltage waveform applied at 8,619 K. Time t
, to t2, the potential of the output terminal 602 of the drive circuit 601 becomes f)Z/-i, and the pixels 606 and 607 are driven. During this time 1. During the period from 11 to 11, the open/close control signal input terminal 618 of the analog switch 616 becomes high, so that the analog switch 616 is conductive and the analog switch 617 is A1.
Since 9 is C, there is no conduction. Therefore, the optical signal of the pixel 606 is output to the read signal terminal 620. In the period from t2 to t3, 618. At the ninth stage when the phase of the signal input to 619 is switched, the Anagsui Ichiro 16 becomes non-conductive and the 617 becomes conductive, and the readout signal terminal 620K stops outputting the optical signal of the pixel 607. Similarly, from t3 to each pixel 608. , 609. 610
．． The optical signal from 611 is output.

FIG. 8 also shows an embodiment of the present invention, in which three pixels are t-driven with one bit output from the drive circuit, and an analog switch is inserted in the readout signal line. In the figure, 801 is a drive circuit, 802 and 805 are output terminals of the drive circuit 801, 806 and 817 are pixels, 818 and 820 are three-series readout signal lines, 821 and 823 are TPT analog switches, and 824 825, 826 are signal input terminals that control the opening and closing of analog switches 821, 822, and 825, respectively, and the terminals of analog switches 827, 822, and 825 are connected to each other.

This is a signal readout terminal to the outside.

Figure $9 is an example of the drive voltage waveform of the 8th stationary body imaging device, and the 90
1. 902. 903 are output terminals 802 . 803. 804 is marked 1, positive waveform, 904. 905. 906 is a voltage waveform applied to the opening/closing control signal input terminals 824825, 8261c of the analog switches 821, 822, 823, respectively. 1 pixel 806 from time tl to t,
807, 808 bz drive me.

The tVC analog switch 821 is conductive between this time and 8
22 and 823 become non-conductive, an optical signal is output from the pixel 806 to the read signal terminal 827.

During the period from t to t, the analog switch 822 is conductive,
Since 821 and 825 are non-conductive, 827 is the optical signal of pixel 807, or the analog signal is not transmitted during period t.
4. The optical signal of the pixel 808 is read out at the ninth point 827, where the switch 825 is conductive and 821 to 822 are non-conductive.

From t to 1.1 to t, etc., the active pixels are sequentially read out from pixels 809°, 55, 810, and so on.

〔Effect of the invention〕

By using the present invention, it is possible to increase the driving speed of one line. Assuming that the number of pixels driven by one drive circuit bit is N, the line drive speed is N times faster than when one pixel moves 2LIK. This means that when polysilicon TPT is used in the drive circuit, the practical operating upper limit frequency of the drive circuit is 5eOKK type, which is particularly effective. By using the present invention, you can achieve as much as 9 things! A solid-state imaging device that can be driven within 71 msec and operates at high speed has been realized.

The present invention is also advantageous when applied to high-resolution solid-state image carriers; even if the number of pixels is multiplied by N, the number of bits in the drive circuit remains the same compared to when driving one pixel with one bit of the drive circuit. The reader output speed can be the same as ζ and others. In particular, when polysilicon TPT is used in the drive circuit, TP
Since the size of the T unit must be increased, the increase in solid-state image sensor chip area due to the trend towards higher resolution can be greatly alleviated. Therefore, even if high resolution is achieved, a low-cost solid-state imaging device with a small chip area will not be realized.
By inserting an analog switch in each of the readout signal lines for multiple series installations, it is possible to extract optical signals in a time-division manner from pixels that are simultaneously driven by the same bit of the drive circuit. This eliminates the need to combine multiple output signals and reduces the number of terminals within the chip.

The present invention can also be applied to a two-dimensional solid-state imaging device that has a high driving speed and a short pixel pitch.

As described above, by using the present invention, a high-performance, low-cost solid-state imaging device has been realized.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining the present invention in detail. 101...Drive circuits 105 to 110...Pixels 111 and 112 have signal readout lines FIG. 2 is a diagram for explaining a conventional solid-state imaging device. @3 Figure is a t diagram showing the equivalent circuit of one pixel. Figure 4 shows the driving voltage waveform of the conventional solid-state tank device shown in Figure 2.
Figure. Figures 11 and 5 are diagrams showing an example of an embodiment of the present invention in which three pixels are driven by one bit of drive circuit output. FIG. 6 is an embodiment of the present invention, showing an example in which an analog switch is inserted in the read signal line. ．． Figure 7'j. Figure t47 is a diagram showing the driving voltage waveform of the solid-state imaging device of the present invention. @Figure 8 is an example of the present invention, [# circuit output 1 bit = 3
Figure 5 shows an example of performing pixel movement and roughly inserting an analog switch into the readout signal line. ! FIG. 9 is a diagram showing the driving voltage waveform of the solid-state imaging device of the present invention shown in FIG. that's all

Claims (2)

[Claims] (1) In a solid-state imaging device comprising a photoelectric conversion element made of a photoreceptor thin film and a drive circuit made of a thin film transistor on an insulating substrate, a plurality of pixels are driven with one bit of output from the drive circuit, and an optical signal is transmitted in a plurality of series. A solid-state imaging device characterized by reading out from a signal line. (2) The solid-state imaging device according to claim 1, wherein an analog switch made of a thin film transistor is inserted into each of the plurality of signal lines, and separate terminals of the analog switch are connected inside the chip.