JP3116687B2 - Linear sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state image pickup device, and more particularly to a linear sensor comprising a light receiving section in which a large number of light receiving elements for performing photoelectric conversion are linearly arranged.

[0002]

2. Description of the Related Art In a linear sensor comprising a solid-state image pickup device using a CCD, light-receiving elements constituting a large number of pixels are arranged in a straight line in a row, and photoelectrically converted in accordance with the intensity of received light to shift this electric charge. The signal is transferred via a register and taken out of the output circuit to obtain a signal output.

FIG. 2 shows an example of the configuration of a conventional linear sensor. A transfer gate 12 is provided on one side in parallel with the linear light receiving section 11, and the CCD shift register 13 is provided to the light receiving section 11 via the transfer gate 12.
Is connected. The shift register 13 has a bus line 14
And an output circuit 15 is connected to one end thereof. The light receiving section 11 has a configuration in which photoelectric conversion elements forming a large number of pixels are arranged in a line in one row.

In the linear sensor having the above structure, the light incident on each pixel of the light receiving section 11 is converted into electric charges in accordance with the light intensity and transferred to the shift register 13 via the transfer gate 12. As described above, the electric signal corresponding to the light amount is sequentially driven by the bus line 14 at a position corresponding to each pixel of the shift register 13 and is sampled and held for a certain period of time, and is directed toward the output circuit 15 as indicated by an arrow H. Will be transferred. The electric signals transferred in time series from the respective pixels of the light receiving unit 11 through the shift register 13 are output to the outside via the output circuit 15 as shown by the arrow J.

FIG. 3 shows another example of the configuration of a conventional linear sensor. In this example, CCD shift registers 24 and 25 are provided via transfer gates 22 and 23 on both sides of a linear light receiving section 21 in which light receiving elements are linearly arranged. Drive bus lines 26 and 27 are connected to the shift registers 24 and 25, and output circuits 28 and 29 are connected to respective ends.

In the linear sensor having the above structure, the light incident on each pixel of the light receiving section 21 is converted into electric charges according to the light intensity, and the pixels are alternately transferred to the transfer gates 22, 23 as indicated by arrows K and L for each pixel. Shift register 2 via
Transferred to 4,25. The signal charges sent to the shift registers 24 and 25 on both sides of the light receiving section 21 are sequentially transferred in the respective shift registers by driving signals from the bus lines 26 and 27 as shown by arrows M and N, and output. The signals are output to the outside via the circuits 28 and 29 as shown by arrows P and Q.

[0007]

However, in the conventional multi-pixel linear sensor shown in FIG. 2, in order to read out an output signal at a high speed, it is necessary to increase the driving frequency of the CCD shift register. For this reason, the amount of driving power increases, and the transfer signal is likely to deteriorate due to the large number of transfer stages in the shift register. Further, since the signal output taken out through the output circuit is sent out at high speed, it is difficult to adjust the phase of the sample hold of the transfer signal waveform at each pixel position in the shift register during transfer, and the frequency characteristics of the output circuit Needs to be increased.

Further, in the conventional multi-pixel linear sensor shown in FIG. 3, signal charges are taken out from both sides of the light receiving portion and transferred to shift registers provided on each side to be transferred. Can be reduced to one-half as compared with the configuration example of FIG. 2, but the pitch of the CCD is doubled as compared with the configuration example of FIG. For this reason, transfer deterioration is likely to occur, and driving at a low voltage cannot be performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks of the prior art, and causes transfer degradation of a high-speed output signal at a low voltage without increasing driving power and without increasing the frequency characteristics of an output circuit. It is intended to provide a linear sensor that can be obtained without using a linear sensor.

[0010]

In order to achieve the above object, a linear sensor according to the present invention is a linear sensor having a light receiving portion in which a large number of light receiving elements constituting pixels are arranged in a straight line in one row. The light receiving unit is divided into a plurality of parts, and a shift register is alternately provided on the opposite side of the light receiving unit via a transfer gate corresponding to each divided portion, and between two shift registers adjacent on one side of the light receiving unit. Is characterized in that a drive circuit and an output circuit are provided for each shift register.

[0011]

The light receiving section in one row is divided into a plurality of portions, and an output signal is generated for each divided portion, and the outputs are multiplexed.

[0012]

FIG. 1 is a configuration diagram of a linear sensor according to an embodiment of the present invention.

The light receiving section 1 is divided into four parts, and a CCD shift register 3 is connected via a transfer gate 2 to each of the divided parts (A) to (D). Each of the divided portions (A) to (D) of the light receiving section 1 has a configuration in which photoelectric conversion elements constituting a large number of pixels are arranged in one row. The four shift registers 3 are alternately arranged on both sides of the light receiving unit 1 in a zigzag manner. Each shift register 3 is connected to a drive circuit 4 composed of an inverter and the like and an output circuit 5 composed of an amplifier and the like. The drive circuit 4 is provided for each shift register 3
On the other hand, as shown by an arrow F, wiring connection is performed so that each pixel portion (not shown) of the shift register 3 is sequentially driven from the side surface side. The output circuit 5 is connected to one end of each shift register 3.

The driving circuit 4 and the output circuit 5
It is provided at a position corresponding to a gap between adjacent shift registers 3 alternately arranged on both sides of the light receiving unit 1. Each drive circuit 4 is a bus line (not shown) for applying a drive pulse.
It is connected to the.

In the four-part linear sensor having the above structure, light incident on each pixel part of each of the divided parts (A) to (D) is converted into electric charge according to the amount of light, Is sent to the shift register 3. The shift register 3 samples and holds a signal charge in order at a position corresponding to each pixel portion for a predetermined time in accordance with a drive signal from the drive circuit 4, for example, as shown by an arrow E in the case of a divided portion (B). To the output circuit 5. The output circuit 5 outputs a signal sent in time series via the shift register 3 to the outside as an output signal as shown by an arrow G. In this way, by dividing one linear light receiving unit 1 into four parts and multiplexing them,
Four multiplexed signals are obtained.

Although the light receiving section is divided into four in the above embodiment, the number of divisions is not limited to four, but may be any number.
Further, the length of each divided portion may be different.

[0017]

As described above, in the linear sensor according to the present invention, the light receiving section is divided, and the CCD shift registers are arranged on both sides of the light receiving section so as to correspond to each divided portion, and each shift section is shifted. Because the output circuit is connected to the register and the output is multiplexed, the output can be read at high speed equivalently without increasing the driving frequency, and it is not necessary to improve the frequency characteristics of the output circuit and the load on the circuit is reduced. Become.

Further, since the degree of freedom of division is large, the degree of freedom of circuit design is increased, and it is possible to easily deal with circuits under various application conditions. In addition, since the CCD shift register is divided and multiplexed, the number of transfer stages is reduced and transfer deterioration is less likely to occur. In addition, since the transfer pitch in the CCD shift register is the minimum pixel pitch, transfer deterioration is further suppressed and low voltage driving is performed. And the phase adjustment of the sample hold can be easily performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a linear sensor according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of an example of a conventional linear sensor.

FIG. 3 is a configuration diagram of another example of a conventional linear sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Light receiving part 2 ... Transfer gate 3 ... Shift register 4 ... Drive circuit 5 ... Output circuit

Claims (1)

(57) [Claims] 1. A linear sensor having a light receiving section in which a large number of light receiving elements constituting a pixel are arranged in a line in a straight line, the light receiving section is divided into a plurality of light receiving sections, and the light receiving sections are alternately arranged corresponding to the respective divided portions. A shift register is provided on the opposite side of the shift register via a transfer gate, and a drive circuit and an output circuit are provided for each shift register and between adjacent shift registers.