JPS59122085A - Solid-state image pickup element - Google Patents

Abstract

PURPOSE:To eliminate blooming even when extremely intense light is incident by allotting two sensor arrays by one transfer shift register and linking two storage shift registers to one transfer shift register. CONSTITUTION:Signal charges are stored in picture elements arranged on a base body in plural arrays at an image pickup part 11, which transfers signal charges of respective picture elements to transfer registers 14 which are installed closely to plural arrays of picture elements in their array directions. Further, storage shift registers 18a and 18b are linked to the registers 14 and a storage part 15 wherein signal charges obtained through the registers 14 are stored is provided. Then, each transfer register 14 is given signal charges of picture elements forming those two adjacent arrays, every two registers 18B and 18A are provided to every transfer register 14, and each of the registers 18A and 18B is put in charge of the storage of signal charges of picture elements in a corresponding array.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a solid-state imaging device, specifically a solid-state imaging device that has both a transfer shift register and an accumulation shift register and is capable of improving smear, and particularly improves sensitivity and pluming suppression. It is designed to improve performance.

BACKGROUND ART AND PROBLEMS The present applicant has previously proposed a novel solid-state imaging device that can improve the degree of smearing, especially when used as a solid-state imaging device for still cameras. First, such a solid-state image sensor will be briefly explained below.

As shown in FIG. 1, this solid-state image sensor is roughly divided into an image section (1), a storage section (2), and a horizontal shift register (3). The image part (1) is an optical system (
This is for generating signal charges based on an optical image formed by a path shown in the figure. Sensor sections (4) consisting of photodiodes and the like are arranged in a matrix in this image section (1).

and the vertical direction of the sensor part (4) (up and down direction in the figure)
A transfer shift register (5) is provided for each column. A readout case (6) is arranged between the transfer shift register (5) and the sensor section (4).
6) allows the signal charges of the sensor section (4) to be shifted to the transfer shift register (5) for each column.

On the other hand, the storage section (2) has the above-mentioned transfer shift register (5).
), the number of storage shift registers (7) corresponds to the number of storage shift registers (7). The transfer end of the transfer shift register (5) is coupled to the transfer start end of the storage shift register (7). And this accumulation shift register (
Each bit of the horizontal shift register (3) is made to correspond to the transfer end of (7). In this case, a signal corresponding to one horizontal line of the image is transferred in parallel to a horizontal shift register, and then serially sent out by the horizontal shift register. Note that (8) in FIG. 1 is a channel stop area.

For example, an interlaced method is used to capture an image using a solid-state image sensor. That is, first, the signal charge of the sensor section (4) indicated by scattered dots is read out in an odd field, and then the signal charge of the sensor section (4) shown in white is sent out in an even field. Specifically, a signal as shown by E in the second diagram is supplied to the transfer electrode of the transfer shift reno star (5). still,
It is assumed that the transfer shift register is driven by a two-phase clock. The vertical retrace period To and the light receiving periods of the sensor section (4) corresponding to odd and even fields are as shown in FIGS. 2A, B, and C. To read out the signal charge of the odd field sensor section (4), that is, the sensor section (4) indicated by the scattered dots, first, drive the transfer shift reno star (5) with the φ moon clock, and read out the princess in it. The charge is swept out, and then a readout pulse P is supplied to the capacitor (6) corresponding to the scattered sensor portion (4). As a result, the signal charges of the sensor section (4) indicated by scattered dots are shifted to the transfer shift register (5), and then φA2
The frame is shifted by the clock indicated by and transferred to the storage shift register (7). In this case, the signal charge stored in the storage shift register (7) via the transfer shift register (5) is accumulated in the sensor section (4) shown scattered in one frame period before the readout pulse shown by PI. It is a signal charge.

A similar operation is performed when reading out the signal charge of the sensor section (4) shown in white in the even field.

In this case, read no 2 Lus P! is transmitted at the timing shown in FIG. 2E.

Note that the signal charges obtained in the odd and even fields mentioned above are transferred to the horizontal shift register (3) during the corresponding vertical scanning period.
) are sequentially read out as a predetermined signal series.

In such a solid-state image sensor, a transfer shift register (5)
By photoshielding the storage section (2) and the horizontal shift renoster (7), smear can be kept small.

By the way, in such a solid-state image sensor, as can be understood from the second diagram E, a predetermined voltage is applied to the transfer electrode of the transfer shift register (5) at a timing other than the retrace period to cause an overflow. It is used as a drain. For example, when light is being received by the sensor unit (4) shown as scattered dots, the energy level of the transfer shift register (5) is lowered (quiet) during the period shown by 'r, l'r2 in E in the second figure. (higher at electrical level) sensor section (
This is to discard the excess signal charge overflowing from 4). However, in this case, when the reverse field analogy is that the sensor unit (4) shown as scattered dots is receiving light, the transfer shift register (5) is Since a CCD operation must be performed, an overflow drain cannot be used, and in this case, the amount of light that generates the maximum allowable charge during this vertical retrace period reaches the limit of blooming suppression. In this regard, the limit for blooming suppression has previously been considered to be several tens of times the saturation load.

Therefore, with such a configuration, it is difficult to suppress blooming against fairly strong light.

Of course, the overflow control dirt and overflow drain sensor parts (4) are attached to the configuration shown in Figure 1.
It is also possible to provide this for each column, thereby suppressing blooming. However, in this case, the light-receiving area of the sensor section (4) is relatively reduced, which has the disadvantage of lowering the sensitivity.

Purpose of the Invention The present invention has been made in consideration of the above-mentioned circumstances, and it is an object of the present invention to suppress blooming and improve sensitivity in a solid-state image sensor having the configuration shown in FIG. Summary of the Invention In the solid-state imaging device of the present invention, the number of transfer shift registers is one for the number of columns of sensor sections. Specifically, two adjacent picture element columns are supported by one transfer shift register. Furthermore, one transfer shift register is associated with two storage shift registers, and these storage registers serve as a receiver for the above-mentioned array of sensor units.

According to this invention, the number of transfer shift registers can be reduced to 1, and sensitivity can be improved.

Furthermore, since an overflow drain and an overflow control date can be formed in the space created by reducing the number of transfer shift registers, blooming suppression can be improved without reducing sensitivity.

In addition, one overflow drain and overflow control cable ``-1'' is provided for each row of two sensor sections.
In this case, the above-mentioned effect can be made even more remarkable.

EXAMPLE Hereinafter, an example of the present invention will be explained with reference to the drawings from FIG. 3 onwards. Note that this embodiment employs an overflow drain.

FIG. 3 shows this embodiment as a whole. In FIG. 3, sensor units 0 are formed in a matrix in the image unit 09. A color separation filter (not shown) is arranged on the front surface of the image section α°C (on the optical system side). and the column (13A) corresponding to ■, C),
The sensor section (2) (13B) is configured to accumulate signal charges of the corresponding color. Each row of the sensor section (2) (
Transfer shift register α for 13A) and (13B)
→ is formed every second. In other words, one column (13A) of sensor sections α is formed via the -ill K readout port (15A) of the transfer shift register 04, and the sensor section α is formed on the other side via the readout gate (15B). and other columns (1
3B) is arranged. Overflow drain O
Q is also formed for every second sensor section 02 (13A) and (13B). In other words, one row (13B) of the sensor sections 02 is arranged on one side of the overflow drain 0Q, and the row (13A) of the sensor sections 02 is arranged on the other side of the overflow drain 0Q.

On the other hand, in the storage section 0~, each column (1) of the sensor section (company)
, 3A) and (13B) are arranged in a number corresponding to the number of storage shift registers (18A) and (18B). And these accumulation shift resistors (18A), (
18B) are each coupled with one transfer shift register α→. Accumulation shift cash register (18A), (18
The terminal end of B) is coupled to one horizontal shift register α, and signal charges are sequentially sent out through each output circuit (A). This point is the same as before.

In order to read out a video signal from the optical image formed on the image section (11) with such a configuration, for example, a drive signal shown in FIG. . and a read case (15A).

(15B) Readout/Grus P1+P shown in Figure 4 B and C
2 is supplied. In this case, when the dirt pulse P1 is supplied to the readout register (15A), the signal charge is shifted from the sensor section 0 of the column (13A) to the transfer shift register 04, and immediately after that, the clock φVIA (fourth Diagram A
) is frame shifted. And the transfer shift register θ→ which has been swept out by this frame shift
Then, the read pulse P2 is supplied to the other read gate (15B), and the signal charge of the sensor section (12) of the other column (13B) is shifted.This shifted signal charge is also supplied to the next timing. It goes without saying that the frame is shifted to the storage section α by the clock φV.

The other storage shift register (18A,), (18B)
is driven by a three-phase clock and has an accumulation shift register (
18A), (18B) second electrode, third city pole φVS
21φvs3 are the same, and the same clock is supplied as shown in the third diagram. On the other hand, the first electrodes are made individual in the storage shift registers (18A) and (18B), ie, φ 1 and φ 1 , and are supplied with a lock of V31 vSl, respectively, as shown in FIGS. 3E and 3F, respectively. As can be understood from the figure, after the signal charge of the sensor section α of the column (13A) passes through the transfer shift register 04, one of the storage shift registers (18A) is transferred because the first electrode φVSt is on (in the driven state).
will be accumulated. The signal charge of the sensor section (12) in the other column (13B) is transferred to the other storage shift register (12).
8B) will be similarly accumulated. Signal πL accumulated in accumulation shift registers (18A) and (18B)
It is unnecessary to explain that the load is converted into a serial signal series by the horizontal shift register α and sent to the outside.

To make it easier to understand, I would like to add an explanation: As shown in FIG. be. Also in this example, an interlaced signal sequence can be obtained, which is the same as in the case of FIG. 1, so the explanation will not be repeated.

In this example, it is only necessary to apply one transfer shift register α→ to two rows of sensor units α9, so the number of transfer shift registers α→ is reduced to 1 compared to before, and the light reception of sensor unit (2) is reduced to 1. The area can be increased. In addition, due to the area reduction by the transfer shift register 04, the overflow drain 0Q and overflow control case are
Blooming can be suppressed without deteriorating sensitivity. For this reason, blooming can be suppressed even in the presence of extremely strong light. Moreover, in this example, only one overflow drain θe is required for each of the two rows of sensor sections α, so that the above-mentioned effect can be made even more remarkable.

Note that this invention is not limited to the above-described embodiments, and various modifications are possible. For example, a transfer shift register may be used as an overflow drain. In this case, as shown in Fig. 5, the transfer clock φ7□ is added to the signal applied to the transfer electrode of the transfer shift register.
. Just take it into consideration. That is, as can be understood by comparing with FIG.
2 shift, a sweep transfer clock φ7.
. is added to the transfer electrode, thereby sweeping out excess charge that had overflowed from the sensor section (6) during the previous light reception period.

As described in detail, according to the present invention, two sensor columns are allocated to one transfer shift register, and two storage shift registers are connected to one transfer shift register. , the same imaging operation as before can be performed with one transfer shift register. Therefore, the proportion occupied by the transfer shift register in the image section can be halved compared to the conventional one, and the light-receiving area of the sensor section can be correspondingly increased to improve sensitivity.

Furthermore, since an overflow drain can be created using the extra space, blooming can be eliminated even in the presence of extremely strong light.

[Brief explanation of drawings]

Fig. 1 is a plan view showing a conventional row, Fig. 2 is a time chart for explaining the conventional example of Fig. 1, Fig. 3 is a plan view showing an embodiment of the present invention, and Fig. 4 is a third cape. - Figure 5 is a time chart to explain the example.
It is a time chart which shows the modification of the example of a figure. Figure 3 Figure 4

Claims (1)

[Claims] Signal charges are accumulated in pixels arranged in a plurality of columns on the substrate, and the signal charges of each of these pixels are transferred to a plurality of transfer shifts arranged in the vicinity of the plurality of columns of pixels along the direction of the columns. an image pickup unit configured to be able to transfer signal charges to a register; an accumulation unit configured to have an accumulation shift register connected to the transfer shift register; and an accumulation unit configured to accumulate signal charges obtained via the transfer shift register; In a solid-state imaging device having an output section that serially reads out parallel signal charges from the transfer end of the register, the signal charges of the pixels in two adjacent columns are transferred to one of the transfer shift registers. and two of the accumulation shift registers are provided for each of the transfer shift registers, so that the signal charges of the pixels in the corresponding column are stored in one of the accumulation shift registers. A solid-state image sensor characterized by being made to have a receptacle.