JPS5962274A - Method for driving solid-state image pickup device - Google Patents

Abstract

PURPOSE:To obtain the smear component with high S/N by stopping a horizontal charge coupling element and operating a vertical charge coupling element only after all signal charges of one field are read out, in an interline charge coupling solid-state image pickup device. CONSTITUTION:When the signal charge from all lines is read out of a CCD 3 after the end of one field period, the signal charge is not included in the uppermost line 31 of the vertical CCD yet. But, the smear component leaked while the charge is transferred as 3N-31 in the vertical CCD is stored therein. Thus, when a pulse phiH of the horizontal CCD is stopped and the transfer for a line's share is performed to the vertical CCD with a pulse 31' of phiv1, phiv2, for example, after the signal charge is transferred from the photoelectric converting element to the vertical CCD with a switching pulse 25, the smear nXs multiplied by (n) is outputted to the output signal 24' during the 1st one horizontal period, by repeating the transfer of the vertical CCD transfer and the readout by the horizontal CCD with pulses 21', 22', 23.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention is an inter-line charge-coupled solid-state imaging device that blocks only the smear component that occurs as a white band above and below a point where strong light is incident. The present invention relates to a method for driving a solid-state imaging device that can achieve high SN without providing a line.

[Prior art]

An example of a two-dimensional solid-state imaging device using a conventional lightning-in-one charge coupling device (hereinafter referred to as COD) is shown in FIG.

In the figure, 2 is a group of photoelectric conversion elements that convert incident light into signal charges. 11.12. ..., IN is a light-shielded CCD that transfers the charge accumulated in the photoelectric conversion element section in the direction of the vertical arrow, and the transfer pulse is synchronized with the horizontal pulse of the television signal. be.

The 7ζ charge accumulated in the photoelectric conversion unit is transferred to the vertically adjacent COD in the vertical retrace period. The transferred signal charges are sequentially transferred upward using pulses synchronized with the horizontal pulses. A CCD 3 transfers charges in the horizontal direction, and outputs signal charges transferred from the vertical COD in synchronization with horizontal pulses from an output terminal 4 as a video signal during one horizontal period.

By the way, in the device shown in FIG. 1, a smear occurs in which white bands appear in the vertical direction at six points hit by strong light, as shown in FIG. This is because the vertical structure of the device in Figure 1 has a CCD for transfer and a photoelectric conversion element (photodiode) adjacent to each other on the same plane as shown in Figure 3, and this occurs on the substrate below the photodiode. Did 1? CC where part of the load is vertical
This occurs because it leaks into D. At this time, as shown in the signal waveform of FIG. 2, the amount of smear varies depending on the position in the horizontal direction, but remains almost constant in the vertical direction of the screen (therefore, it is applied to a band in the vertical direction).

Conventional smear removal is performed as follows. That is, as shown in the schematic diagram of FIG. 4, there are n lines (n is 1 or more) of fluorophore 5 between the light receiving section 4 and the CCD 3 in the horizontal direction.
As shown in FIG.
) 21', 22', 23
Read the signal by: As a result, a smear 24' (nXs) multiplied by 5 is obtained in the first horizontal quadrant. As a result, the SN of the smear 24' can be obtained with a high SN compared to the video coefficient slope, so the circuit shown in FIG.
A television signal without smear and with little 8N degradation is obtained by the signal processing circuit 8 through the smear removal circuit 10' having the TV signal.

However, in the above-described first driving method, it is necessary to provide a light shielding part to the solid-state image sensor, which has the disadvantage of increasing the area of the element.

[Purpose of the invention]

The purpose of the present invention is to eliminate the need for such a light shielding part.
It is an object of the present invention to provide five driving methods for a solid-state imaging device that can obtain only high SN smear components.

[Embodiments of the invention]

FIG. 7 is a diagram showing an embodiment of a method for driving an inter-line type charge-coupled solid-state imaging device according to the present invention.

As shown in FIG. 3, CCDs 1, 12, .・・・・・・This is generated by the signal charge leaking into the IN, and the signal charge accumulated in the photoelectric conversion element is leaked while being transferred from the bottom to the top of the light receiving part inside the vertical CCD in order to read out the signal charge accumulated in the photoelectric conversion element. The integral of the accumulated charge is the second
Output as a smear of the figure. By the way, after completing one field period, the signal ftt from all lines is transferred to CCD3.
When read from the vertical COD top line 31
No signal charge is already included within. However, there are 3N, 3(N-11...) inside the CCD in the vertical direction.
....

32.31, the leaked smear components are accumulated during the transfer.

Therefore, the horizontal CCD3 pulse φnk stops November G
If, for example, n lives are transferred (where !1 is an integer greater than or equal to 1 and less than or equal to the ratio of the line period to the horizontal period of No. 11) using the pulses 31' of φVl and φV, the switch pulse 25, the signal charge is transferred from the photoelectric conversion element to the vertical COD, and after ft a pulse 21'
, 22', and 23, the vertical CCD transfer and the horizontal COD readout +a:・* are repeated, so that the output signal 24' in the first horizontal period has 5
The multiplied smear nxs can be output. By passing this output signal through a circuit similar to the conventional one shown in Fig. 6,
A television signal without smear and with little SN deterioration can be obtained.

〔Effect of the invention〕

As explained above, by using the method for driving an inter-line type charge-coupled solid-state imaging device according to the present invention, a smear signal with a higher SN than a video signal can be obtained without providing a light-shielding part in the solid-state imaging device. A television signal with less S/N deterioration due to smear removal can be obtained.

[Brief explanation of drawings]

Figure 1 is a block diagram of a conventional inter-line charge-coupled solid-state imaging device, Figures 2 and 3 are illustrations of the nature and causes of smear generation, and Figures 4, 5, and 6 are A conventional solid-state imaging device provided with a light-shielding section to remove smear, a schematic diagram of the conventional solid-state imaging device, its driving method, and a block diagram of a smear removal circuit.
1 Hidaka 3 Figure 4 Figure 4 γ Figure 6 Figure 6

Claims (1)

[Claims] 1. A plurality of photoelectric conversion elements arranged two-dimensionally, a plurality of charge-coupled devices that vertically transfer signal charges accumulated in each photoelectric conversion element, and a plurality of charge-coupled devices that transfer signal charges accumulated in each photoelectric conversion element in a vertical direction; Read the signal charge horizontally in one horizontal period,
In a solid-state imaging device consisting of a protruding charge-coupled device, 1
After reading out all the signal charges in the field, stop the horizontal charge-coupled device and operate only the vertical charge-coupled device, which corresponds to n lines (however, n is 1 or more and less than or equal to the ratio of the vertical retrace period to the horizontal period). (an integer of
After that, signal charges are transferred from the photoelectric conversion element group to the vertical charge-coupled devices, and signals are read out by the horizontal charge-coupled devices and transferred to the vertical charge-coupled devices alternately to drive the solid-state imaging device. Method.