JPS60137178A - Solid-state image pickup device - Google Patents

Abstract

PURPOSE:To improve the performance of a two-dimensional solid-state image pickup device provided with charge transfer elements by driving the charge transfer element of a horizontal register on three-phase basis. CONSTITUTION:When a three-phase register is used as the charge transfer element 8, information can be stored at positions corresponding to two phases among three phases. Therefore, two signals from two picture elements can be stored in the charge transfer element 8. Consequently, a vertical signal line 4 is swept in the beginning of a horizontal blanking period to sweep excessive charges out through a gate 10, and picture elements (a) and (b) and signals charges on one lateral line are read in the charge transfer element 8. Gates 5 and 6 are turned off during a horizontal scanning period to read a signal successively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a photodiode array in the light receiving section, and uses a charge transfer element (Charge) as a readout horizontal register.
The present invention relates to a two-dimensional solid-state imaging device equipped with a transfer device (hereinafter abbreviated as CTD).

FIG. 1 shows an example of a sensor having a diode array in the light receiving section and a CTD in the readout register (Utility Application No. 157030/1983).

In the figure, ■ is a photodiode, 2 is a vertical switch MI
S l-transistor, 3 is vertical scanning circuit, 4 is vertical signal line, 5 (5'), 6 (6') are Goo1-Ml5 transistor, 7 (7') is output amplifier, 8 (8') is cTD as a horizontal register, 9(9') is an input part of 4iCTD, and 10(10') is a blooming suppression circuit. Normally, CTD8 (8') consists of two phases (Hl, l-1
2 pulse) or quasi-4 phase. 7. to the vertical signal line 4 during the horizontal scanning period. The accumulated pseudo signals such as blooming and vertical smear are swept out through the gates 1 to 5 and 10 at the beginning of the horizontal and horizontal blanking periods. Thereafter, the pixels in the horizontal row indicated by ■ in FIG.
The data is transferred to the memory section 1 of each memory section.

The above operation is performed in the first half of the horizontal blanking period, and in the second half, the signal corresponding to the horizontal row of the diode indicated by ■ in the figure is transferred to the CTD register of the channel ■ in the lower part of Figure 1. Go to step 1. During the horizontal scanning period, the gates 6 and 6' are turned off, the CTD is driven, and two lines of signals are simultaneously read out from the output amplifiers 7 and 7'. The purpose of reading two lines of signals at the same time is to improve the resolution of the image as a single-plate color sensor. Figure 2 shows each pulse,
In particular, the timing chart 1 of the front part of the horizontal blanking period
− is indicated.

Now, the above example has the following problems.

■ ■, ■ The number of chip bins is large because it drives two channels of CT D and G1~.

■ In FIG. 1, in order to correct variations in the threshold voltages of gates 5 and 5', external charges are transferred from the blooming suppression circuit 10' to the vertical signal line 4, and then the charges are transferred to the outside through the gates 10' again. A sweeping operation is required.

(2) Therefore, the time required to transfer the desired signal charge to the CTD (2) and (3) is shortened.

■ Since the gains of the output cuffs and 7' of both CTDs are different, noise and noise are generated.

The present invention solves the above problems and improves the performance of solid-state imaging devices.

FIG. 3 shows an embodiment of the present invention. The features of this example are:
The CTD 8 as a horizontal register is, for example, a three-phase drive CTD (Patent N〆'2) having the cross-sectional structure shown in FIG.
8711).

In the cross-sectional view (A) of the CTD in FIG. 4, 41 is the first electrode material, and 42 is the second electrode. 46 is an oxide film, 4
3 is, for example, an ll-type Si layer, and 44 is a P-type S layer, which is the opposite type to 43.
It is 1. 45 is a layer in which impurities such as boron are ion-implanted between the first electrodes 41; The feature of this CTD is that one of the three-phase pulses (B) is applied to a pair of first and second electrodes connected to each other. Therefore, considering the region corresponding to the pulse of each phase, for example, the region 3 in FIG. 4, the potential within the channel 43 is non-uniform.

Now, let's return to Figure 3. If a three-phase register is used as a CTD as shown in FIG. 3, information can be stored in locations corresponding to two of the three phases. Therefore, 2
CT D of two signals from pixels (■ and ■ in the figure)
8 can be stored. In this embodiment, the operation during the horizontal blanking period (1-IBL) is as follows.

■ At the beginning of the horizontal blanking period, the vertical signal line 4 is cleaned and excess non-signal charges are swept out through the gate IO.

■ CTD the signal charge of the pixel ■ and its horizontal direction - rows.
Load into 8.

■ Shift CTD by one phase.

■ Next, the signal charge for one row that resounds in the pixel ■ is CTD
Load into 8.

Gates 5 and 6 are used during the horizontal scanning period. ffL drives the CTD and sequentially reads out the signals.

In this way, it is possible to solve the problems that existed in the conventional embodiments, and it is possible to expect a significant improvement in the performance of solid-state imaging devices by applying the present invention.

FIG. 5 shows another embodiment of the invention. This device uses a priming transfer type image sensor (S, Terakava et al.
al; IEEE, Electron De
vice Letter.

No, 5. 1980). Even in this case, by using the CTD as a three-phase drive register, signals from two pixels can be read out simultaneously to obtain a high-resolution image.

In addition, in the embodiments shown in FIGS. 3 and 5, CTD8 is set to 2.
If a phase drive or four-phase drive register is used and the number of stages is twice the number of horizontal pixels, more microfabrication technology will be required than when using a three-phase drive CTD. , it is possible to read the signals of two pixels with one register.

In the embodiment shown in FIG. 6, three phases C'r'D8.8' are provided above and below. At this time, before reading the information of the pixels indicated by ■ and ■ in the figure, remove the excess noise charge.

Read out to lower CTD 8, 8' or one CTD.

If you do this, you will get a 2-pixel signal ■.

It is possible to read out the noise charge ■ and the noise charge ■, and finally sweep out only the noise charge ■ to the outside.

In the embodiment shown in FIG. 7, only one four-phase CTI') 8 is provided to read out the noise charge (2) and the signals (2) and (2) of the two pixels, respectively.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the configuration of an MO3 type imaging device using the CTD register readout method, Fig. 2 is a diagram showing the drive pulse (for channel ■) in Fig. 1, and Fig. 3 is a diagram showing an embodiment of the present invention. , FIG. 4 is a diagram showing the structure (A) of a three-phase drive CTD and drive pulse CB), and FIGS. 5, 6, and 7 are diagrams showing other embodiments of the present invention. 1 ・Ho 1 diode, 2 ・Vertical switch (insulated G1~ type field effect transistor, etc.), 3 ・Vertical scanning circuit, 4 ・Vertical signal output line, 5, 6 ・Transfer gate ( Insulating goo 1 ~ type field effect 1 - transistor etc.), 8.
・・CTD, 10・ Recesso 1 ~ Game 1 ~ (Insulation Goo 1
~ type field effect transistor, etc.). Figure 5 Figure 8 Figure 6

Claims (1)

[Claims] ■. During the horizontal blanking period, the pseudo signal on the vertical signal line is read out, and then the signal on the vertical signal line is read out to a charge transfer element, which is a horizontal register, and during the horizontal scanning period, the charge transfer element is switched off. In a solid-state imaging device that is driven to read out signals, the charge transfer element, which is the horizontal register, is
A solid-state imaging device characterized by sum drive. 2. The solid-state imaging device according to claim 1, wherein the charge transfer element serving as the horizontal register is driven in two phases and has twice the number of stages as the number of horizontal pixels. 3. In claim 1, simultaneous reading of two lines is performed, and two of the charge transfer elements for the three phases are read out simultaneously.
A solid-state imaging device that stores signals in two electrodes, transfers them, and reads out the signals.