JPS60163583A - Drive system of charge transfer-type area image sensor - Google Patents

Abstract

PURPOSE:To conduct an interlace action, to reduce an after-image and to improve picture quality by summing charges of two photosensitive picture elements transferred to each line direction register and outputting them from a row direction register. CONSTITUTION:Two pieces of photosensitive picture elements 1i,1-1i,2n are arrayed in the line direction on a line address-type area image sensor, a photosensitive picture element array 2i is made, and m sets of photosensitive picture elements 2i are arrayed in the row direction opposite to the line direction. In correspondence to the arrayes 2i-2m, line direction registers 3i-3m are provided, and a row direction register 4 is installed on one end of the registers 3i-3m. Control gates 7i,1-7m,2n are provided between respective picture elements 1i,1- 1i,2n and the registers 3i-3m, and charges accumulated in the picture elements 1i,1-1i,n are transferred to the register 3i. A well having the common potential is formed downstream of transfer gates 11i,1-11i,2 of the register 3i, and sums up the transferred charges. By control of an address circuit 9, an interlace action is conducted, and after-images are reduced and the picture quality can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for driving a charge transfer type area image sensor when obtaining a standard television image signal using the charge transfer type area image sensor.

[Technical background of the invention]

FIG. 1 is a plan view showing the element configuration of a line address type area image sensor, which is one of the charge transfer type area image sensors. This area image sensor includes 2n photosensitive pixels Jt, k, each consisting of a pn junction photodiode, each of which generates and accumulates charges in response to light.
(k=1.2...2 n) 1 arranged in i column direction
By configuring one photosensitive pixel column 21 and further arranging m photosensitive pixel columns 21 (1=1.2...m) in the row direction perpendicular to the column direction, a total of (2nXm) pixels are photosensitive. It makes up the department. A column direction register 31 consisting of seven COD resistors is provided corresponding to and adjacent to each photosensitive pixel column 21, and one end of each column direction register 31 is provided with an extension of each column direction register 31. A row direction register 4 consisting of a COD shift register extending in a direction perpendicular to the direction is provided. The column direction register 31 sequentially transfers the electric charges accumulated in the photosensitive pixels zi, k in each corresponding photosensitive pixel column 21 to the row direction register 4 based on a control signal. Furthermore, this row direction register 4 is the column direction register 3.
The charges transferred by 1 are now sequentially transferred in the row direction based on a control signal, and the charges transferred here are detected by the charge detection section 5 provided at the tip of the row direction register 4. The signal is converted into an electrical signal, and then sequentially outputted from the output terminal 6.

Further, the photosensitive pixel 11. In order to transfer the charge accumulated in k to the corresponding column direction register 31, each photosensitive pixel Ji,
Control 1' F 7i is arranged between the column direction register 31 corresponding to the photosensitive pixel and the column direction register so as to be adjacent to each other.
, k (1"1.2 ,"'m, k =1.2...
・2n) is provided. These controls) 71. Those arranged in the corresponding rows are the same. They are connected in parallel to each signal line 8k, and these signal lines 8 are selectively driven by the output signal from the address circuit 9. It has become.

When a line address type area image sensor having such a configuration is driven according to a standard television imaging system, an interlaced operation is performed. This interlacing operation has conventionally been performed as follows. In the case of interlaced operation, odd fields and even fields are alternately successive, and when it is an odd field, the address circuit 9 selects the first and third rows.

...Signal line 81 corresponding to the (2n-1)th row.

83...J? 2n-1 are sequentially driven, and the photosensitive pixels 11, 1, 11, 3, ... 1 i , 2n in odd rows are
-1 adjacent to the control r-) 71. ,．． 7
1,5,"'7i, 2n-1'ft are operated sequentially.The above control r-door 1,1.71.3'"'7i,
2n-1 operates, in each photosensitive pixel column 21, the first, third, ... (2n-1)th odd row photosensitive pixels 11, 1, 11, 3, "' 1 i , 2n-
The charge pre-stored in one is transferred to the corresponding column direction register 31 via the adjacent control dart. The charges transferred to these column direction registers 31 are transferred to the row direction registers 4t.
- is transferred to the charge detection section 5 via the charge detection section 5, and then converted into an electrical signal and output from the output terminal 6.

On the other hand, in the case of an even field, the signal lines 8 . . . corresponding to the 2nd row, 4th row, . . . ．． 84, . . . 82n k are sequentially driven,
Even-numbered row photosensitive pixels 11.2n Ji, 4, . . . Ji,
Control dart 71.2.2 located adjacent to 2n
By sequentially operating 1, 4, . . . 7i, zn', charges are read out in the same manner as above.

[Problems of Background Art] In the above-described conventional driving system, charges are read out from each photosensitive pixel Jik once every two fields. That is, if the field period is Tf, then the period of continuous charge output from each pixel is 2Tf. Therefore, an afterimage of about 2Tf will occur for moving subjects! l), the television picture based on the signal obtained with this sensor will be very unsightly.

In solid-state imaging devices such as line-address type area image sensors, the area of the imaging section (photosensitive section) of the entire device is small (approximately 20 mm), so moiré phenomena tend to occur, resulting in poor image quality. There is a subcommittee.

[Purpose of the invention]

This invention was made in consideration of the above-mentioned circumstances), and its purpose is to be able to completely reduce afterimages during interlacing operation, to roughly reduce the occurrence of moiré phenomena, and to improve image quality. An object of the present invention is to provide a driving method for a charge transfer type area image sensor that can improve the performance.

[Summary of the invention]

In order to achieve the above object, the present invention combines the charges of the photosensitive pixels in two adjacent rows in the column direction, and simultaneously
Alternatively, the charges are sequentially transferred to the corresponding column direction registers, and the charges of these two photosensitive pixels are added and read out as a signal.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In the driving method according to the present invention, in the case of a 0-odd field, the line address type area image sensor having the configuration as shown in FIG. First, the signal lines 81882 corresponding to the first and second rows are simultaneously driven by the address circuit 9. Then, the photosensitive pixels 11, 1.1 in the first and second rows in each photosensitive pixel column 21
Control r-doors 1, 1 provided 14 adjacent to 1, 2
．． 71,2 are opened at the same time, and each of the above two photosensitive pixels 1
Charges previously stored in 1, 1, N, and 2 are transferred to the corresponding column direction registers 31. The above two photosensitive pixels 1
As shown in the potential state diagram of FIG. Control signals with the same phase are supplied to the transfer darts I Ji, 1251.111.2 of the column direction register 31, which are
A common potential well 12 is formed below 11.2. For this reason, the two photosensitive pixels 11, 1 b
The charges transferred from Ji,2 are transferred to the column direction register 31.
are stored together in the well 12 formed by the . That is, the charges from the 52 photosensitive pixels are stored in the column direction register 3.
It is added by being transferred to 1. The addition of these two charges is performed from each photosensitive pixel column C to each column direction register 31.
This is done in parallel when the charges are transferred. Next, each column direction register 31 transfers the added charge in the column direction to the row direction register 4 by sequentially valves the common potential wells formed under each of the two transfer darts.

The row direction register 4 sequentially transfers the charge f transferred by each column direction register 31 to the signal detection section 5 in the row direction.

Therefore, after this, from the output terminal 6, the two photosensitive pixels 11 in the first row and the second row in each photosensitive pixel column 21 are output.
, 1, 11, and 2 are sequentially output as electric signals for one row.

Next, signal lines 83 and 84 corresponding to the third and fourth rows are simultaneously driven by the address circuit 9. Then, the photosensitive pixels 11 in the third and fourth rows in each photosensitive pixel column 21
, 5.11, the control group F provided adjacent to 4
yt, s% 71.4 are opened at the same time, and the charges previously stored in each of the two photosensitive pixels 11.3.11, 4 are transferred to the corresponding column direction register 31. In this case, similarly to the above, in the column direction register 31, control signals having the same phase are supplied to the two transfer darts provided adjacent to the control gates 71jb 7i, 4, respectively. The charges transferred from the two photosensitive pixels to the column direction register 31 are accumulated together in a potential well formed under the two transfer darts and are added together.

Then, the charges added by the lever are transferred to the row direction register 4 via the column direction register 31, and roughly transferred to the signal detection section 5 via the row direction register 4. From the output terminal 6, two photosensitive pixels 11.3.11 in the third and fourth rows in each photosensitive pixel column 21 are output.
, 4 are sequentially output as electric signals for one row. After this, the same operation as above is performed on the 5th and 6th lines, the 7th and 8th lines, etc.
The process is repeated up to the n-1)th line and the 2nd nth line.

Next, only the signal line 81 corresponding to the first row is driven by the address circuit 9, and the control circuit provided adjacent to the photosensitive pixels 11, 1 of the first row in each photosensitive pixel column 21 is driven. Goo) 71.1 will be held.

As a result, the charges previously accumulated in the photosensitive pixels 11, 1 of each first row are transferred to the corresponding column direction register 31, and this charge is sequentially transferred via the column direction register 31 and the row direction register 4. Although the signal is transferred and output from the output terminal 6, this signal is not used as a painter signal. The charge read operation is performed during the field blanking period.

When an even field follows the odd field, the address circuit 9 simultaneously drives the signal lines &, . . . , Ss corresponding to the second and third rows. At this time, the control gates 75z, 71.5 provided adjacent to the second and third rows of photosensitive pixels 11, 2.11.5 in each photosensitive pixel column 21 are simultaneously opened, and each of the above Charges previously stored in the two photosensitive pixels 11.2, Jl, 3 are transferred to the corresponding column direction registers 31. In one column direction register 31 that receives charges from the two photosensitive pixels 11, 2, 11, and 3, the control is performed in the same manner as above.
The transfer r-) of the column direction register 31 provided adjacent to each of 71, 2, C, and 5 has a position.

Control signals of equal phase are supplied, and this transfer f-
A common potential well is formed below the top.

Therefore, the charges transferred from the two photosensitive pixels 411, 2. are added by being transferred to the column direction register 31. The addition of these two charges is performed in parallel when the charges are transferred from each photosensitive pixel column 21 to each column direction register 31. Next, each column direction register 3
1 transfers the calculated charges in the row direction register 4t in the column direction through common potential wells e7i formed under each of the two transfer darts. The row direction register 4 sequentially transfers the charge transferred by each column direction register 31 in the row direction to the signal detection unit sf. Therefore, after this, from the output terminal 6, each photosensitive pixel column q
Two photosensitive pixels 21 in the second and third rows in .l.
The sum of the charges of 2%11.3 is sequentially output as one row's worth of electrical signals.

Next, signal lines 84*86 corresponding to the fourth and fifth rows are simultaneously driven by the address circuit 9. Then, the photosensitive pixels 11 in the fourth and fifth rows in each photosensitive pixel column 21
, 4.11.5)
71.4b, 7t, and s are simultaneously opened, and the charges previously stored in each of the two photosensitive pixels 1i, 4% Ji', and 5 are sent to the corresponding column direction register JIK41. Similarly, in the column direction register 3t, control signals having the same phase are supplied to the two transfer darts provided adjacent to the control darts 71, 4, C, and 5, respectively, so that the two photosensitive The charges transferred from the pixels to the column direction register 31 are accumulated together in the potential well formed under the two transfer gates and multiplied by 7J11.Then, this added charge is transferred to the column direction register 31. Row direction register 4 via 31
, and further transferred to the signal detection section 5 via the row direction register 4. After that, the output terminal 6 outputs the signals from the fourth and fifth rows in each photosensitive pixel column 21. The sum of the charges of the two photosensitive pixels Ji, 4-zt, and s is sequentially output as an electric signal for one row.

After this, the same operation as above is performed on the 6th and 7th rows,
This is repeated until the (2n-2)th line and (2n-1)th line, such as the 8th line, the 9th line, and so on.

Next, only the signal line 82n corresponding to the second digit is driven by the address circuit 9, and the control provided adjacent to the 2nth row of photosensitive pixels 11, 2n in each photosensitive pixel column 21 is driven. Gates 7i and 2n are opened. For this,
Charges previously accumulated in each of the second n-th row photosensitive pixels 71.2n are transferred to the corresponding column direction registers 31, and these charges are transferred to the column direction registers 31 and the row direction registers 4' (
Although the signals are sequentially transferred via i- and output from the output terminal 6, this signal is not used as an image signal.

The charge read operation is performed during the field blanking period. After this, the field returns to the odd field and the same operation is repeated.

By repeating the above operations in odd and even fields, in the odd field, the 2nd (-1)th row and the 2nd (-K) row of each photosensitive pixel column 21 are = 1, 2, ・n) are sequentially output as electrical signals for one row.
The sum of the charges of the two photosensitive pixels in the (2nd and +1)th rows is sequentially output as an electrical signal for one row, thereby performing an interlacing operation. According to this embodiment, charges are read out from each photosensitive pixel it, k for each field. For this reason, the charge readout period from each pixel is F k )' M Tt
Accordingly, the afterimage of about 2 Tf that conventionally occurs can be reduced to half of that amount of Ti. Since the rough calculation of the charges of two photosensitive pixels is made to correspond to the image signal of one running tatami line segment, the effective spacing of the photosensitive pixels in the column direction is two pixels. Therefore, the MTF (amplitude modulation factor) for the scanning line in the column direction is 0, and the occurrence of moire phenomenon can be significantly suppressed compared to the conventional method.

It goes without saying that the present invention is not limited to the above-mentioned embodiments, but that various modifications are possible.

For example, according to the above embodiment, the (2-1)th row and the second row of each photosensitive pixel column 21 or the second row and the (
When transferring the electric charge of each of the two photosensitive pixels in the 2nd +1) row to the corresponding column direction register 31, the control gates 7 provided adjacent to each of the two photosensitive pixels are simultaneously opened, and On the register 31 side, as shown in FIG. 2, we have explained the case where a common potential well is formed under the two transfer darts and the charges from each two photosensitive pixels are added, but this is due to the above two controls. The darts 7 are sequentially opened at different times, and the charges transferred to the column direction register 31 are transferred individually as shown in the potential diagram in FIG. 3, and are added when transferred to the row direction register 4. It's okay. Furthermore, although the above embodiment has been described for a case where it is applied to a black and white sensor without a color filter, it goes without saying that this can also be applied to a color sensor that has a color filter all over the photosensitive pixel. .

〔Effect of the invention〕

As explained above, according to the present invention, a drive method for a charge transfer area image sensor can reduce afterimages during interlaced operation, and further reduce the occurrence of moiré phenomena, thereby improving image quality. can be provided.

[Brief explanation of the drawing]

Fig. 1 is a plan view of a line address type area image sensor, Fig. 2 is a potential state diagram for explaining an embodiment of the present invention, and Fig. 3 is a potential state diagram for explaining the present invention in detail. be. DESCRIPTION OF SYMBOLS 1... Photosensitive pixel, 2... Photosensitive pixel column, 3... Column direction register, 4... Row direction register, 5... Signal detection section, 7... Control dirt, 9... Address circuit, 1
1...Transfer dart.

Claims (2)

[Claims] (1) A photosensitive section with a plurality of photosensitive pixel columns arranged in a column direction in which photosensitive pixels that generate and accumulate electric charge in response to light are arranged in a row direction perpendicular to the column direction, and each of the plurality of photosensitive pixel columns. A column direction register is provided corresponding to the column direction and transfers the charge accumulated in each photosensitive pixel in the column direction, and a column direction register is provided adjacent to each of the plurality of photosensitive pixel columns and transfers the charge accumulated in each photosensitive pixel with a control signal. a control dart that selectively transfers the charges to the corresponding column registers according to the voltage, and a row register that transfers charges transferred by the plurality of column registers in the row direction and outputs the same to the outside. In a charge transfer type area image sensor, in one of two consecutive fields, each (2nd curtain-1)th and each 2nd row of the plurality of photosensitive pixel columns (K is a positive integer of 1 or more) ) are transferred as a pair to the corresponding column direction register, and the charges of each two photosensitive pixels transferred to each column direction register are added and transferred from the above row direction register. In the other of the two fields, the charges stored in the photosensitive pixels corresponding to the 2nd and (2+1)th rows of the plurality of photosensitive pixel columns are paired and output in the corresponding column direction. A charge transfer type area image sensor characterized in that an interlace operation is performed by adding charges of two photosensitive pixels transferred to each column direction register and outputting the result from the row direction register. drive method. (2) By selectively operating the control darts provided adjacent to the photosensitive pixels corresponding to each two rows of the plurality of photosensitive pixel columns, the charge of the photosensitive pixels corresponding to each of the two rows is changed. 2. A driving method for a charge transfer type area image sensor according to claim 1, wherein the charge transfer type area image sensor is configured to transfer the charge transfer type area image sensor to the corresponding column direction register.