JPH01168060A - Charge transfer device - Google Patents

Abstract

PURPOSE:To shift and horizontally transfer by a normal periodic pulse waveform by so wiring the electrode pattern of a transfer electrode for 2-phase-driving a horizontal CCD as to displace phase by one phase through a shift gate between the horizontal CCDs. CONSTITUTION:A horizontal transfer electrode 17 for forming two horizontal CCDs (HCCDs) 13, 14 is provided with 2-layer polysilicons Poly1, Poly2 arranged horizontally with two as one set, and driving pulses phiA, phiB are so applied between the first HCCD 13 and the other second HCCD 14 disposed near at a photodetector 10 that the phases between the electrodes disposed oppositely become reverse. To this end, the 2-layer polysilicons Poly1, Poly2 are so obliquely wired at a position formed with a shift gate electrode 12 that the transfer electrodes of the first and second HCCDs 13 and 14 are displaced horizontally by one from one each other.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a charge transfer device, and more particularly, to a charge transfer device that facilitates multi-line readout.

[Prior art]

As a charge transfer element, a so-called multi-line readout element has been proposed in which a plurality of horizontal CCDs are arranged in parallel and connected to each other at the output end of a light receiving part, and the signal charge generated in the light receiving part is distributed to each horizontal COD and read out. ing.

In such a charge transfer element, for example, two rows of photoelectric conversion elements adjacent to each other in the vertical direction of the light receiving section are assigned to one scanning line, and signal charges generated in the first row are supplied to a first horizontal CCD. However, it is suitable for a color image image sensor provided so that the signal charges of the second row are supplied to the second horizontal COD and the two rows are read out in combination.

That is, in the color image sensor, by arranging color filters with different color patterns in each of the two rows, color separation is improved and a complete color signal is generated within one scanning line. can be obtained, and a high-resolution color image can be obtained.

[Problem that the invention seeks to solve]

However, the charge transfer element having the above structure has the disadvantage that the driving waveform of the horizontal CCD becomes complicated due to the allocation of signal charges.

That is, to illustrate and explain the electrode pattern in the horizontal transfer section of the charge transfer element in FIG. 5, two horizontal CC
The horizontal transfer electrodes 3 constituting the DI, 2 are made of a two-layer structure of polysilicon Po1yl, Po1, which has a plurality of layers arranged in the horizontal direction.
y2, and the horizontal transfer electrode is provided so as to be divided into two approximately at the center by a third polysilicon Po1y3. The Po1y3 is contacted with the substrate through a window 4 formed in a partial region of the two-layer polysilicon Polyl and Po1y2 to form a shift gate 5, and the potential of the gate portion is changed. IJ? Wholesale.

The horizontal transfer section configured in this way uses three types of drive pulses φA and φ as shown in FIG. 6 for charge transfer.
B, φC and shift gate pulses φ, G were required.

Moreover, the charge injected into the packet of the electrode 3 to which the drive pulse φ1 is applied in the first horizontal CCDI (in the figure,
Indicated by a black circle. ) to the opposite electrode of the second horizontal 〇CD, as is clear from FIG. 6, the drive pulse φ8. φC becomes an irregular pulse, making the drive waveform complicated.

Further, in order to normally drive the two horizontal CCDIs 2, drive pulses corresponding to the respective electrodes were required. Furthermore, in such a horizontal transfer section, normal horizontal transfer is stopped until the shift operation is completed, so extra time is wasted for reading out the charges.

SUMMARY OF THE INVENTION An object of the present invention was made in view of the above circumstances, and it is an object of the present invention to provide a charge transfer element that can perform shifting and horizontal transfer using a normal periodic pulse waveform.

[Means and effects for solving the problem] That is, the above object of the present invention is to convert the signals of photoelectric conversion elements arranged in a matrix into at least two horizontal CODs connected in parallel to each other via shift gates. In a charge transfer element that is distributed to and read out in a horizontal transfer section consisting of a charge transfer element, the electrode pattern of the transfer electrode that drives the horizontal COD in two phases is wired so that the phase is shifted by one phase between the horizontal CCDs via a shift gate. This is achieved by a charge transfer element characterized by:

By wiring the two horizontal CCDs so that the phases of the transfer electrodes arranged in correspondence with each other are opposite to each other, the signal supplied to one horizontal CCD is transferred to the horizontal CCD.
A separate horizontal CCD can be created by simply controlling the shift gate provided between D.
The signals can be easily allocated.

〔Example〕

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

FIG. 1 is a block diagram showing one embodiment of a charge transfer device according to the present invention. In this embodiment, a case will be described in which two horizontal CODs (HCCDs) connected in parallel are driven in two phases.

In the figure, the light receiving section 10 and the vertical transfer section 11 are simplified and shown as one block.

That is, the light receiving section 10 includes a plurality of light receiving elements arranged in a matrix, and the vertical C corresponding to the vertical rows of the light receiving elements.
A vertical transfer section 11 consisting of an OD is arranged, and a horizontal transfer section to be described later is arranged on the output side of this vertical transfer section 11.

The horizontal transfer section is composed of two HCCDs 13 and 14 which are connected in parallel to each other via a shift gate electrode 12, and each has a buffer amplifier 15.1 at its output terminal.
6 is connected.

FIG. 2 illustrates an electrode pattern in the horizontal transfer section of the charge transfer element.

The horizontal transfer electrodes 17 constituting the two HCCDs 13 and 14 are made of two-layer polysilicon Po1y1. Provided by Po1y2.

The feature of the present invention is that the first HCCD13 and the other second HCCD are arranged close to the light receiving section 1 side.
14, drive pulses φ, φ, are applied so that the phases between the electrodes disposed opposite to each other are opposite to each other. Therefore, the two-layer polysilicon Po1yl, Po1
y2 is a location where a shift gate electrode 12, which will be described later, is formed, and the transfer electrodes of the first HCCD 13 and the second HCCD 14 are wired diagonally so that they are shifted by one line from each other in the horizontal direction. Therefore, the same drive pulse φ as the horizontally adjacent electrode is applied to the electrode of the second HCCD 14 opposite to the electrode to which the drive pulse φ is applied to the first HCCD 13. It is set in.

The two-layer polysilicon Po1y1. On Po1y2, the two-layer polysilicon Po1yl and Po1y2 are located approximately in the center.
A third polysilicon Po1y3 is arranged so as to intersect with the polysilicon layer, dividing the two-layer polysilicon into two parts, upper and lower. The third polysilicon Po1y3 is a partial region of the two-layer polysilicon Po1yl and Po1y2, and in this embodiment, 5
A shift gate 12 is formed by contacting the substrate through a window 18 opened corresponding to the transfer electrode.

It should be noted that Po1y1.corresponding to the window 18. Since Po1y2 is disconnected, it is wired so as to be continuous outside the transfer path area.

Next, the operation of the charge transfer device according to the present invention configured as described above will be explained with reference to FIGS. 3 and 4.

Signal charges generated in the light receiving section 10 are transferred by the vertical transfer section 11 and sent to the first HCCD 13. At this time, if the shift gate 12 is provided at L level and the potential barrier of the gate is in a high state, the charge is not shifted to the second HCCD 14 and the drive pulse φ^ applied to each transfer electrode.

Normal horizontal transfer is performed by two-phase driving by φ. On the other hand, the first HCC to which the drive pulse φ is applied
When charge is injected into the packet under the electrode of Dl3 and the shift gate 12 is set at H level to set the potential level deep to a predetermined potential, the charge is injected into the packet under the electrode of the corresponding second HCCDl4. will be shifted to. At this time, the charge under the electrode of the first HCCD 13 is not transferred in the horizontal direction, and the charge under the electrode of the first HCCD 13 is not transferred horizontally.
FIG. 4 shows how the electrode is shifted below the electrode.

That is, the potential level under each transfer electrode is different between Po1yl and Po1y2 for charge transfer, and this difference acts as a barrier between horizontally adjacent packets (1=1+). - side, first H
The charges injected into the deep potential level of CCDl 3 are transferred to the lower potential level of the corresponding second HCCDl4 under the Polyl electrode before the potential level under the horizontally adjacent Poly2 electrode becomes relatively deep due to horizontal transfer. Since the potential level of (t”b
), are shifted to the second HCCD 14 without being horizontally transferred.

The charge shifted to the second HCCDl 4 is transferred to the first H
Similar to the horizontal transfer in the CCD 13, the signal is driven in two phases by drive pulses φA and φ crown and horizontally transferred. Note that at this time, an L level voltage is applied to the shift gate electrode 12, and this shift gate portion acts as a vertical potential barrier.

〔Effect of the invention〕

As described above, according to the charge transfer element of the present invention, since the transfer electrodes of the corresponding horizontal CD are wired so as to have opposite phases, distribution can be performed only by shift gate operation, and The transfer pulse is performed as a periodic pulse without irregular portions even during shifting, which simplifies drive control. Furthermore, horizontal transfer and shift operations can be performed in parallel, and the time required for shift operations is also shortened.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a charge transfer device according to an embodiment of the present invention, FIG. 2 is an electrode wiring diagram in the horizontal transfer section of the device in FIG. 1, and FIG. 3 is a timing diagram explaining the operation. 4 is a perspective view schematically shown to explain the operation, FIG. 5 is an electrode wiring diagram of the conventional element, and FIG. 6 is a timing diagram showing the operation of the conventional element. 10: Light receiving section, 11: Vertical transfer section, 12: Shift gate electrode, I3: First HCOD, 1
4: Second HCCD, 15, 16: Buffer amplifier, 17: Horizontal transfer electrode, 18: Window 2, Figure 33 Figure 4 "0°°' 6-111 Drunk Figure 5 Figure 6 Φ5q

Claims (1)

[Claims] In a charge transfer element that distributes and reads signals from photoelectric conversion elements arranged in a matrix to a horizontal transfer section consisting of at least two horizontal CCDs connected in parallel via a shift gate, the horizontal CCDs are driven in two phases. A charge transfer element characterized in that electrode patterns of transfer electrodes are wired so as to shift the phase by one phase between horizontal CCDs via a shift gate.