JPH01241264A - Photoelectric converter - Google Patents

Abstract

PURPOSE:To save an external memory and to reduce the cost by arranging plural lines of optical sensors of one line each comprising a photodetection section and a light shielding section while the photodetection sections are arranged side by side. CONSTITUTION:R, G, B signals obtained from a photoelectric converter 201 are held by a sample-and-hold S/H circuit and stored in an external memory 202 via an A/D conversion circuit. At first signals R1, G2, Bn+3 are held in the S/H circuit, the signal R1 is a read signal with respect to the read original position, the signal G2 is the 2nd line position and the signal Bn+3 is the (n+3)th line position read signal. Signals R2, G3, Bn+4 of the succeeding line position are read, the signals R1, G2, Bn+3 are A/D-converted and stored in an external memory 202. Similar operations are repeated, finally signals R, G, B of the same original position are read and outputted simultaneously. Thus, the memory capacity M' of the required minimum of the external memory 202 is expressed in equation I and since line sensor R, G photodetection sections are arranged side by side, then the readout of signals Rn+3 and Gn+3 is a difference of one step. Thus, the memory quantity is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photoelectric conversion device in which a plurality of line sensors each including a light receiving section and a light shielding section are arranged in a plurality of lines.

[Conventional technology]

FIG. 5 shows a conventional photoelectric conversion device using sound. It is a schematic block diagram of a reading system.

As shown in the figure, the photoelectric conversion device 101 has three
It is composed of a line sensor, and each line sensor is composed of a light shielding part 11 and a light receiving part 12.

A sensor drive system and a signal transfer output system are formed in the light shielding section 11, and light receiving surfaces of optical sensors are arranged in the light receiving section 12. In addition, in this conventional example, each of the three lines is red (R).
, green (G), and blue (B) filters, forming a color line sensor.

The lengths of the light blocking section 11 and the light receiving section 12 in the line sensor arrangement direction (vertical direction) are n bits and 1 bit, respectively. 1
The bit corresponds to the light receiving part of one photosensor cell, and is, for example, in the shape of a square with a negative side of 10 μm.

In this way, each line sensor corresponding to RGB has a different position, so when the R signal of a certain line of the document is obtained at the 9th point, the G signal is the position of the document of the (n+2)th line from that line, and the B The signals are the signals at the document position of the (2n + 3)th line.

Therefore, in order to obtain RGB signals at the same document position, the RGB signals must be input to sample and hold circuits (S, 4()).
It is necessary to store at least the previously outputted GB multiplied signal in the external memory 102 via the GB and GB conversion circuits. This external memory will be further explained.

6(A) to 6(D) are the steps in which the RGB signals are stored in the external memory. FIG.

First, in the S first step, R11'n+21B2n
A +S signal is output from each line sensor and held in the circuit (S/) (see figure).

Here, one step is a vertical movement of the optical sensor relative to the document, and lsy lag corresponds to a movement of one bit. Suffix of each signal (1, n+
2, 2n+3) is the position of the document corresponding to each signal (((expressed in number of lines with respect to the document position of the R signal. The same applies hereinafter.

Subsequently, in the second step, the next line is read by each line sensor, and each S/i (the R2*Gn+5 + 82n+4 signal is held in the circuit and the 'R1''n+2' 82H+5 signal is ψ
It is converted and stored in the external memory 102 ((B) in the same figure)
.

The above steps are repeated, and the RGB signals are sequentially stored in the external memory 102. And the (2n +
3) When the step is reached, the B2n+5 that was read first
The R2n+5 signal of the line at the same yK position as the signal is subsequently taken and held in the S/)1 circuit. 02n+ in the same position
As shown in the figure, since the three signals have already been read at the (n+2)th step, the RGB signals at the same document position are obtained only at the (2n+3)th step. Then, as shown in (e) and (D) of the same figure, k
Therefore, the external memory 102 requires a minimum capacity iM expressed by the following equation.

M = (2n + 2 + n + 1) , 4
For the line sensor, a memory capacity of @l''t (5n+5) x (number of bits of the line sensor Nm) is required.

[Problem to be solved by the invention]

However, in the conventional example described above, since the external memory IJ cannot be made smaller than the above-mentioned capacity fM, it is not possible to fully improve the utilization efficiency of the entire memory.

It is also disadvantageous in terms of cost.

An object of the present invention is to provide a photoelectric conversion device t that can save external memory IJ and achieve cost reduction.

[Means to solve the problem]

The photoelectric conversion device according to the present invention is characterized in that a plurality of lines of optical sensors each including a light receiving section and a light shielding section are arranged adjacent to the light receiving section t.

[Effect]

By arranging all of the light receiving sections adjacent to each other, it is possible to simultaneously output the reading signals from each line sensor at the same document position with a significantly smaller capacity than in the past. Therefore, it is possible to save external memory and ultimately reduce costs.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIGS. 1A to 1C are schematic layout diagrams of line sensors showing first to third embodiments of the photoelectric conversion device according to the present invention, respectively.

FIG. 2A shows an example in which two-line sensors are arranged.

The light receiving part 12i of each line sensor is placed adjacent to each other, and RG is
This is a method of reading out the BB double signal from the other double signal.

Figure (B) shows an example in which 3-line sensors are arranged in gold.

The light receiving sections 12 of the two-line sensor that outputs the RG multiplied signal are placed adjacent to each other.

FIG. 2C shows an example in which four line sensors are arranged.

Light receiving section 12 of the 2-line sensor that reads the W (white) R signal
and a light-receiving section 12 of a two-line sensor for reading out GB multiplied signals are arranged adjacent to each other.

Hereinafter, the case of the 3-line sensor (second embodiment) shown in FIG. 3(B) will be explained as an example.

FIG. 2 is a schematic diagram of the image reading system used in this embodiment.

As shown in the figure, a photoelectric conversion device 1i2 according to this embodiment
The RGB signals obtained from 01 are each held in one S/) circuit and stored in the external memory 202 through the ψ conversion circuit.

FIGS. 3-3D are explanatory diagrams showing steps in which RGB signals are stored in the external memory 202.

First, in the first step, R1+G2*B
The n+4 signal is held in the S//H circuit. The G2 signal is the second line based on the document position where the R4 signal was removed.

The Bn+3 signal is a read signal at the (n+3)th line position.

B2' at the position of the primary line in the second step
GS' Bn+4 signal is detected, R1" 2
'Bn+5 signal is A/'D converted and sent to external memory 20
2. The same operation is repeated thereafter, and the (nth
+3) In the step, Bn+! in the first step. The document position where the l signal was stacked is now taken three times as the Rn+5 signal. As a result, RGB at the same document position
Signals can be read and output simultaneously.

Therefore, as shown in (C) CD in the same figure, the minimum memory M'fl required for the external memory 202 is expressed by the following formula % M= (n+2+1)X (Number of bits of line sensor N5)= ( n+3)X (Number of bits of line sensor N
m) In this example, since the light receiving parts of the R and G line sensors are arranged adjacent to each other, Rn+
There is only a one step difference between the reading of the 3 signal and the Gn+3 signal. In comparison, the memory capacity itt can be reduced by 2nX (the number of bits of the line sensor Nm) compared to the conventional method.

The same applies to 2-line sensors and 4-line sensors.

In a 2-line sensor, conventional M - (n+1)XN s
In contrast to the following, in the present invention, it becomes M'-IXNs,
The memory capacity is reduced by nXN5. In a 4-line sensor, L is conventionally M-(5n+5)XNm, but in the present invention it is M'-(3n+6)xN-, which is 2nXNs.
memory capacity is reduced.

The photoelectric conversion device according to the present invention can be applied to any type of optical sensor, such as a photodiode, MOS type, SIT type, transistor, etc., regardless of the type of optical sensor.

Next, as a specific example of this embodiment, a base storage type optical sensor will be described.

FIG. 4(A) is a schematic plan view showing a part of the line sensor adjacent to the light receiving part; FIG. 4(B) is a sectional view taken along line I-1; FIG. 4(C) is a - FIG. 3 is an equivalent circuit diagram of an optical sensor cell.

In FIGS. 4A and 4B, one layer 402 is formed by epitaxial growth on an n substrate 401, and p space regions 404 and 405 are fully diffused therein with a region 403 serving as an element isolation region sandwiched therebetween.

Subsequently, n+ emitter regions 406 and 407 are formed in p base regions 404 and 405, respectively, and a reset transistor Q? The p+S regions 408 and 409 are carefully formed, and the dart electrode 4 is formed through an insulating layer.
10 and 411. Then, light shielding films 412 and 413 such as a cap film are formed, and the light receiving part 12 and the light shielding part 11 are
Divide into.

In this photosensor cell, p pace regions 404 and 405
When photo-excited carriers accumulate in , a sensor signal corresponding to the accumulated voltage is read out to the emitter side, and the carriers remaining in the base are transferred to the reset transistor Qr, l ON
It is removed by Therefore, the base storage al
The base potential can be made completely uniform regardless of the t-pressure, and the afterimage characteristics can be improved and noise can be completely reduced.

A plurality of line sensors in which such optical sensor cells are arranged in a line in the vertical direction of the paper of FIG.

Next, an example of an image reading device to which the present invention is fully applied will be shown.

FIG. 7 is a schematic configuration diagram of an example of an image reading device.

In the figure, a document 501 is mechanically moved in the direction of arrow X relative to a reading section 505.

However, the image is read by scanning in the direction of arrow X using the image sensor 504.

The light from the light source 502 is reflected by the original 501, and the reflected light passes through the entire imaging optical system 503 and reaches the image sensor 50.
Form an image on 4. As a result, the image sensor 5
04, carriers are accumulated in response to the intensity of the incident light,
It is photoelectrically converted and output as image No. 13.

This image signal is digitally converted by an AD converter 506 and taken into a memory in an image processing unit 507 as image data. Processing such as shading correction and color correction is then performed on the image, and the image is sent to a printer 508 or a printer.

When the image signal transfer for scanning in the X direction is completed, the original 501 moves relatively in the X direction, and by repeating the same operation, the previous image of the original 501 is converted into an electrical signal and transmitted as image information I can put it out.

〔Effect of the invention〕

As explained in detail above, the photoelectric conversion device i according to the present invention has light receiving sections arranged adjacent to each other, so that the reading signals from each line sensor at the same document position can be output simultaneously with a significantly smaller capacity than conventional ones. Can be done. However, it is possible to save external memory and reduce costs.

[Brief explanation of the drawing]

Figures 1 (A) to (C) are schematic diagrams of line sensors showing first to third embodiments of the photoelectric conversion device according to the present invention. Figure 2 is a schematic diagram of an image reading thread using the second embodiment. Fig. 3 (A) to (D) Fi, RG in external memory 202
FIG. 2 is an explanatory diagram showing a system in which a B signal is stored. Fig. 4 is a schematic plan view showing a part of the line sensor height where the light receiving part is adjacent to the light receiving part, Fig. 4 (B) is a sectional view taken along the line I-I, and Fig. 4 (C) is a - light Is the equivalent circuit diagram of the sensor cell, Figure 5, a conventional photoelectric conversion device? A schematic configuration diagram of the image reading system used; FIGS. 6(A) to (DJ) are explanatory diagrams showing steps in which RGB signals are stored in an external memory; FIG. 7 is a schematic diagram of an example of an image reading device. It is a configuration diagram. 11... Light shielding section, 12... Light receiving section, 201... Photoelectric conversion device, 202... External memory. Agent Patent attorney Minoru Yamashita Figure 1 (A) (8) (C)
Figure 2 Figure 3 (A) (8) Figure 4 (B) (C)

Claims (1)

[Claims] (1) A photoelectric conversion device characterized in that a plurality of lines of optical sensors each consisting of a light receiving section and a light shielding section are arranged with the light receiving sections adjacent to each other.