JPH03278575A - Driving method for solid state image sensor - Google Patents

Abstract

PURPOSE:To eliminate such drawback as unsettled black color on the screen by driving a first horizontal transfer register and a second horizontal transfer register having a plurality of potential wells, disposed between a charge detection/output section and the first horizontal transfer register, with individual pulses. CONSTITUTION:A second horizontal transfer register 5 having a plurality of bits is disposed between a first horizontal transfer register 4 adjoining to a vertical transfer register 3 and a charge detection/output section 6. Charges transferred from the vertical transfer register 3 to the first horizontal transfer register 4 are transferred to the second horizontal transfer register 5 by driving the first horizontal transfer register 4 with discontinuous pulses phiH1, phiH2. The second horizontal transfer register 5 transfers the charges to the charge detecting section 6 by means of driving pulses phiH1', phiH2' provided from another driver.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for driving a solid-state image sensor, and particularly to a method for driving a horizontal transfer register.

[Conventional technology]

In a charge transfer type solid-state image sensor, as shown in FIG. 3(a), charges generated by photoelectric conversion by a photodiode l in a light receiving section are transferred to a vertical transfer register 3 by a transfer gate 2, and then transferred to a vertical transfer register 3. 3 to horizontal transfer register 4 in parallel, horizontal transfer registers 4 and 5
The charge is transferred to the charge detection/output section 6 through the charge detection/output section 6. The driving pulses for the horizontal transfer registers 4 and 5 are shown in FIG. 3(b).
As shown in FIG. 3, a blanking period is required to stop driving in order to receive and take charge from the vertical transfer register 3. In addition, capacitive coupling 1 as shown in Fig. 4 is established between the electrode of the horizontal transfer register, the pressure gate electrode, and the charge detection section.
2.13 exists, crosstalk due to the discontinuity of the drive pulse during the blanking period is transmitted from the horizontal transfer register to the charge detection section 15 through this capacitive coupling 12.13. As a result, level fluctuations as shown in FIG. 5(a) occur in the output signal. This level fluctuation of the output signal leads to the occurrence of a level difference in the blanking period 17, as shown in FIG. 5(b).

[Problem to be solved by the invention]

If the level difference in the blanking period mentioned above is large, the dynamic range of the signal clamp circuit will deviate, resulting in
The DC component of the video signal is no longer accurately reproduced, which affects the reproduction of the black level of the video signal. Furthermore, when horizontal aperture correction is performed using a signal with a step difference, the aperture is also detected from the step component, which has the disadvantage of causing the signal at the left end of the image to rise or fall.

[Means to solve the problem]

A method for driving a charge transfer solid-state image sensor according to the present invention includes a first horizontal transfer register adjacent to a vertical transfer register, and a plurality of horizontal transfer registers provided between a charge detection/output section and the first horizontal transfer register. A second horizontal transfer register having a potential well is driven with separate pulses.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1(a) is a configuration diagram of a solid-state image sensor for explaining one embodiment of the present invention.

A multi-bit second horizontal transfer register 5 exists between the first horizontal transfer register 4 adjacent to the vertical transfer register 3 and the charge detection/output section 6 .

1st. The second horizontal transfer registers 4 and 5 have the same structure, with only the electrodes separated, and can perform continuous transfer by applying the same pulse to each transfer electrode. The charges transferred from the vertical transfer register 3 to the first horizontal transfer register 4 are generated by discontinuous pulses φH1 and φH with a blanking period as shown in FIG. 1(b).
By driving the first horizontal transfer register 4 at 2, the data is transferred to the second horizontal transfer register 5. In the second horizontal transfer register 5, charges are transferred to the charge detection section 6 by driving pulses φH,', φH2' generated by a drive device different from φH1 and φH2. Therefore, conventional transfer of signal charges at least during the video period is possible.

Note that φH2 and φH2' are φH1l and φH1', respectively.
It is an inverted version of . When the second horizontal transfer register 5 of several bits immediately before the charge detection section 6 is driven with continuous pulses in this way, crosstalk due to the discontinuity of the drive pulse in this part does not occur, and capacitive coupling The crosstalk from the charge detection/output section 6 through the drive is also attenuated while propagating through this continuous drive section. As a result, the crosstalk of the drive pulses in the output signal is reduced, and the influence on the screen can also be reduced.

FIG. 2(a) is a block diagram of another embodiment of the present invention. A first horizontal transfer register 4 adjacent to the vertical transfer register 3
The driving pulses φH1 and φH2 of φHr 'φH2' are generated by ANDing the horizontal blanking only pulse as shown in FIG. 2(b) inside the element.

This allows the scale of the external circuit to be reduced. The effect on the stroke during the blanking period is the same as in the embodiment shown in FIG.

〔Effect of the invention〕

As explained above, the present invention provides an output signal during the horizontal blanking period due to crosstalk due to discontinuity of the drive pulses by driving several bits immediately before the charge detection/output section of the horizontal transfer register with continuous drive pulses. As a result, defects such as floating black on the screen can be improved.

[Brief explanation of drawings]

FIG. 1(a) is a structural plan view of the solid-state image sensing device of the present invention, FIG. 1(b) and (c) are waveform diagrams of driving pulses of the horizontal transfer register, and FIG. FIG. 2(b) is a waveform diagram of a horizontal blanking pulse; FIG. 3(a) is a plan view of the configuration of a conventional solid-state imaging device; FIG. b) is a waveform diagram of the driving pulse of the horizontal transfer register, FIG. 4 is a configuration plan view of the charge detection section of the solid-state image sensor, FIG. 5(a) is a waveform diagram of the output signal, and FIG. 5(b) is a diagram of the waveform of the output signal. FIG. 3 is a waveform diagram of sample and hold output. 1...Photodiode, 2...Transfer gate, 3...Vertical transfer register, 4...
...Horizontal transfer register, 5...Horizontal transfer register, 6...Charge detection/output section, 7...
φH1, φH2 generation circuit, 8...2 layer poly-Si
Electrode, 9...Two-layer poly-Si electrode, lO...
...Ion implantation region, 11, 12.13...Coupling capacitance, 14...Charge detection section, 15...
Reset electrode, 16... Output section, 17...
...Blanking period.

Claims (1)

[Claims] 1. A first horizontal transfer register adjacent to a vertical transfer register, and a second horizontal transfer register having a plurality of potential wells provided between a charge detection/output section and the first horizontal transfer register. 1. A method for driving a solid-state image sensor, characterized in that the first and second horizontal transfer registers are each driven with separate pulses in a charge transfer type solid-state image sensor having a horizontal transfer register. 2. The solid-state imaging device according to claim 1, wherein the first horizontal transfer register is driven by a pulse having a periodic stop period, and the second horizontal transfer register is driven by a continuous pulse. Driving method.