JPH07183995A - Reader - Google Patents

Abstract

PURPOSE:To obtain an inexpensive reader having high resolution and sensitivity. CONSTITUTION:A pair of semiconductor chips 4a and 4b of a reader unit is arranged in a main scanning direction so that photoelectric conversion element arrays P1 to P64 may be parallel with each other in the main scanning direction. The semiconductor chip 4a of one side is arranged so that it is shifted from the semiconductor chip 4b by 1/2 of the pitch S of the photoelectric conversion element in the main scanning direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reading device which can be used in a facsimile machine, an image scanner or the like and which can obtain a high pixel density.

[0002]

9 is a perspective view of a reader unit 1 of a conventional reader, FIG. 10 is a partial cross-sectional view taken along the section line X--X of FIG. 9, and FIG. 11 is a section of FIG. It is a fragmentary sectional view along line YY. The reading device unit 1 includes a light source 2 such as a plurality of LEDs (light emitting diodes) for illuminating a document 9, and a lens 3 arranged to form reflected light from the document 9 to form a document image. , 64 photoelectric conversion elements P1 to P arranged to receive the original image
A semiconductor chip 4 having 64 (hereinafter, referred to as “photoelectric conversion element P” collectively), a substrate 5 to which the semiconductor chip 4 is fixed, and the like are configured.

The light emitted from the light source 2 illuminates the original 9 in an oblique direction, and the reflected light from the original 9 forms an image of the block A on the original by the lens 3 and forms the image on the semiconductor chip 4. By sequentially scanning the provided plurality of photoelectric conversion elements, the read signal corresponding to the above-described image information is output in time series. The housing 7 that holds the lens 3, the semiconductor chip 4, etc. is provided with light-shielding plates 7a on both sides for preventing ambient light. The light-shielding plate 7a on one side is not shown and is omitted.

As shown in FIG. 12, the reader unit 1 includes a printer mechanism section 2 of a word processor 11.
It is attached instead of the ink ribbon cassette and is electrically connected to the main body of the word processor 11 to read a document. That is, although the printer mechanism of the word processor 11 is normally used as a printer,
By replacing the ink ribbon cassette with the reading device unit 1, the reading device unit 1 can read the original set in the word processor 11 while moving in the M direction, and can be used as a reading device.
The image information read by the reading device unit 1 is sent to the main body of the word processor 11.

By mounting the reading device unit 1 on the word processor 11 in this manner, as shown in FIG. 13, the reading device unit 1 displays the image information on the document set in the word processor 11 on the light receiving surface 10. By repeating the main scanning in sequence by the photoelectric conversion elements P1 to P64, the original 9 is moved by moving in parallel with the y-axis.
The image information of the block A1 is read. The width S of the A1 block is the length of the area read by the photoelectric conversion elements P1 to P64, and corresponds to 64 pixels. Next, the document 9 is fed by a pitch width S in the x-axis direction, and the reading device unit 1 repeats the above-described operation to read the information of the A2 block of the document 1. The reading device unit 1 sequentially reads the image information of the document 1 for each block by sequentially repeating such operations.

[0006]

In the conventional reader, the information of the original is reduced and image-formed on the photoelectric conversion element P by the lens 3, and the reduction ratio is 1 / 2.5. Figure 1
4, the photoelectric conversion element P of the semiconductor chip 4
Has a pitch L1 of 50 μm (original pixel pitch is 125
μm), the resolution of the semiconductor chip is 8 dots /
mm. In the arrangement direction of the photoelectric conversion elements P, a region for separating the photoelectric conversion elements P from each other is required,
In particular, in the case of the transistor type photoelectric conversion element P, a certain area is required to form a junction region serving as a channel stopper. Therefore, the element width L3 of the photoelectric conversion element P is 34 μm.
m. Further, the distance L2 between the photoelectric conversion elements is 16 μm.
m, and the unreadable area on the document is 40 μm.

However, recently, there is an increasing demand for high resolution in the reading device. The reason for this is that the resolution on the printing device side is generally 16 dots / mm, so if the reading device is also adjusted to that resolution, software can be easily developed and combined with a printing device with high resolution. A reader can be obtained.

In order to realize the above-mentioned contents, the wiring rule of the photoelectric conversion element P needs to be 1/2 of the conventional one, which is a problem in terms of production technology. Further, since the area of the photoelectric conversion element P is 1/4, the output voltage of the sensor becomes low, the S / N ratio becomes small, and the sensitivity decreases. Further, there is also a problem that the reading speed decreases as much as the dot density increases.

An object of the present invention is to provide a reader which has both high resolution and high sensitivity and is low in cost.

[0010]

SUMMARY OF THE INVENTION According to the present invention, an optical system for forming reflected light from a document to form a document image, and a large number of optical systems arranged in a row for receiving the document image. A reading device comprising a pair of semiconductor chips having a photoelectric conversion element, wherein the pair of semiconductor chips are arranged such that the photoelectric conversion element rows are parallel to each other in a main scanning direction, and one of the semiconductor chips is provided. The reading device is characterized in that the chip is arranged so as to be offset from the other semiconductor chip by ½ of the photoelectric conversion element pitch in the main scanning direction.

Further, the present invention is characterized in that the distance between one semiconductor chip and the other semiconductor chip in the sub-scanning direction is an integral multiple of the photoelectric conversion element size in the sub-scanning direction.

[0012]

According to the present invention, a pair of semiconductor chips are arranged for one optical system such as a convex lens so that the photoelectric conversion element rows are parallel to each other in the main scanning direction, and the photoelectric conversion elements are arranged in the main scanning direction. By arranging them so that they are shifted by ½ of the pitch, the document information received by the convex lens is imaged on both semiconductor chips. As a result, in one semiconductor chip, the width between adjacent photoelectric conversion elements is close to that of one photoelectric conversion element, and reading cannot be performed in that region. However, this unreadable area can be read by the other semiconductor chip. For this reason, it is possible to read at about twice the resolution of the conventional one.

According to the present invention, the distance between both photoelectric conversion elements P in the sub-scanning direction is n times the photoelectric conversion element size (n: natural number). By doing so, when one photoelectric conversion element reads the document information at a specific position and then scans n cycles in the sub-scanning direction, the other semiconductor chip can read the document information at the specific position. become. Therefore, by combining the read data of both semiconductor chips corresponding to the same document position by software, high-resolution reading can be performed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a reader unit 3 of a conventional reader.
1 is a perspective view, FIG. 2 is a partial cross-sectional view taken along the cutting line XX of FIG. 1, and FIG. 3 is a partial cross-sectional view taken along the cutting line YY of FIG. The reading device unit 31 includes a document 39.
A light source 32 such as a plurality of LEDs (light emitting diodes) for illuminating the light source, a lens 33 arranged to form reflected light from a document 39 to form a document image, and the document image received. Pair of semiconductor chips 4a, 4b having a large number of photoelectric conversion elements arranged for
It is composed of a substrate 35 to which a and 4b are fixed.

The light emitted from the light source 32 illuminates the original 39 in an oblique direction, and the reflected light from the original 39 forms an image of the block A on the original by the lens 33, and the light is emitted to the semiconductor chip 35. By sequentially scanning the plurality of provided photoelectric conversion elements, the read signal corresponding to the image information of the document 39 is output in time series. In addition,
A housing 37 that holds the lens 33, the semiconductor chip 4, and the like is provided with light-shielding plates 37a on both sides for preventing ambient light. The light-shielding plate 37a on one side is not shown and is omitted. In addition, as shown in FIG.
4b are displaced from the optical axis of the lens. But,
Such a deviation does not actually cause distortion in image formation or decrease resolution.

FIG. 4 is a partially enlarged view of the semiconductor chips 4a and 4b shown in FIGS. The semiconductor chip 4 is 6
The light receiving surface 10 including the four photoelectric conversion elements P1 to P64 and a terminal S0 for outputting a scanning end signal, a terminal CLK to which a scanning block signal is input, and a terminal VD to which a power source is connected
D, ground terminal GND, terminal SI that outputs a read signal
G, a ground terminal AGND for an analog circuit, and a terminal SI to which a scan start signal is input.

When scanning the document 39, first, a scanning start signal is input to the terminal SI of the semiconductor chip 4, the 64 photoelectric conversion elements P1 to P64 are scanned, and the read signal is sent to the terminal S.
After being sequentially output from the IG, a scanning end signal is output from the terminal S0, and a read signal for one scanning line of the document 60 is output in time series.

The size of each photoelectric conversion element P is 34 μm in the main scanning direction, 50 μm in the sub-scanning direction, and the interval between adjacent elements is 16 μm. The pitch between the adjacent photoelectric conversion elements P is 50 μm. Each photoelectric conversion element P is composed of a phototransistor. A channel stopper region is provided between adjacent photoelectric conversion elements to prevent photocurrent from flowing into the adjacent photoelectric conversion elements. When a phototransistor having such a structure is used, this channel stopper region does not read image information, so that the resolution is lowered.
Since it is used in combination with a 2.5 convex lens, the size of the photoelectric conversion element 50 μm × 34 μm is 12 on the original.
This corresponds to 5 μm × 85 μm. Also, by using a convex lens and a semiconductor chip at a ratio of 1: 1, 8 dots / mm
The resolution of is obtained.

FIG. 5 is a circuit diagram showing an electrical configuration of the semiconductor chip 4 shown in FIG. The semiconductor chip 4
Is a plurality of photoelectric conversion elements P1 to P64 such as phototransistors and photodiodes, and each photoelectric conversion element P1 to P1.
A common signal line CL to which the output from P64 is commonly connected, a plurality of switching elements SW1 to SW64 such as transistors and analog switches interposed between the photoelectric conversion elements P1 to P64 and the common signal line CL, and each switching element. It is composed of a shift register 40, which is a scanning circuit for sequentially driving SW1 to SW64, and the common signal line CL further includes a condenser 42 for an integrator.
And a switching element 41 forcibly setting the potential during blanking scanning that does not output a read signal to the ground potential,
An inverter 48 and a capacitor 47 for capacitively coupling a signal having an opposite phase with respect to a clock signal CLK which is a main noise source are connected in series, and a signal transmitted through a common signal line CL is output from an operational amplifier 43 and resistors 45 and 46. Is input to the non-inverting amplifier. By adjusting the resistance 45, the amplification degree of the non-inverting amplifier can be adjusted.

This operation will be described with reference to the timing chart of FIG. When the reflected light from the document 39 is imaged by the lens 33 and is received by each of the light source conversion elements P1 to P64 of the semiconductor chip 4, a photoelectromotive force corresponding to the amount of received light is generated. On the other hand, when the scan start signal SI is input to the shift register 40, the rising edge of the clock is detected in synchronization with the clock signal CLK to detect the pulse signal D1.
By outputting ~ D64, the switching element S
W1 to SW64 are sequentially turned on. Then, an electric signal corresponding to the photoelectromotive force generated in each of the photoelectric conversion elements P1 to P64 is output to the common signal line CL in time series, amplified by the operational amplifier 43 to a predetermined level, and shown in FIG. Is output as the read signal SIG. The blanking time during which the clock signal CLK is at the high level is set to 0V which is the ground potential when the switching element 41 becomes conductive.

FIG. 7 is a plan view of the semiconductor chips 4a and 4b shown in FIGS. As shown in this figure, the semiconductor chip 4a and the semiconductor chip 4b are arranged back to back so that the respective photoelectric conversion elements P1 to P64 are parallel to each other in the main scanning direction, and the semiconductor chip 4a is placed on the semiconductor chip 4b. On the other hand, they are arranged so as to be displaced by ½ of the pitch S of the photoelectric conversion elements in the main scanning direction. Further, the distance L5 between the photoelectric conversion element P of the semiconductor chip 4a and the photoelectric conversion element of the semiconductor chip 4b is 250 μm, which is five times the photoelectric conversion element size = 50 μm in the sub-scanning direction.
And corresponds to 5 pixels.

As shown in FIG. 7, the reading device having the semiconductor chips 4a and 4b arranged as shown in FIG.
A case where the document 50 indicated by is read in the sub-scanning direction M10 will be described. Each area a (a11, a1) of the document 50
, A13, ..., Corresponds to the pixels corresponding to the photoelectric conversion elements P. Therefore, when the semiconductor chip 4a is scanned for the first time, the areas a11, a13, a1 on the original document are scanned.
5, ..., The read image data is shown in FIG. 8 (2).
Are stored in the memory 51 indicated by. The image data of the area an is defined as an '. At the same time, the semiconductor chip 4b reads the areas a62, a64, a68, ... On the original, which are shifted from the area read by the semiconductor chip 4a by about 1 pixel in the main scanning direction and by 5 pixels in the sub scanning direction, The read image data is stored in the memory 52 shown in FIG. Similarly, the semiconductor chip 4a is similar to that shown in FIG.
As shown in (2), the image data read in each scan is stored in the memory 51, and the semiconductor chip 4b stores the data read in each scan in the memory 52 as shown in FIG. Store.

In this case, when the image data in the memory 51 and the image data in the memory 52 are combined, the data in the memory 53 shown in FIG. 8 (4) is obtained. As shown in the memory 53, the image data obtained by combining the image data read by the sixth scan of the semiconductor chip 4a and the image data read by the first scan of the semiconductor chip 4a is an image on the same line. This is data, which corresponds to image data having a resolution of 16 dots / mm, and has twice the resolution of the conventional one.

Similarly, the image data read by the seventh and subsequent scans of the semiconductor chip 4a and the semiconductor chip 4b are similarly processed.
By sequentially synthesizing the image data read in the second and subsequent times, it is possible to sequentially obtain image data of 16 dots / mm. Here, the semiconductor chip 4a and the semiconductor chip 4b have independent drive circuits, and the respective photoelectric conversion elements P can simultaneously perform reading in the main scanning direction. Therefore, the resolution is improved and the reading speed is not reduced.

As shown in FIG. 7, the semiconductor chip 4a
Ideally, the area read by the semiconductor chip 4b is equal to the image area not read by the semiconductor chip 4a by shifting the semiconductor chip 4b and the semiconductor chip 4b. However, the image area where the semiconductor chip 4a cannot be actually read has a width of 40 .mu.m on the original document, and the width of the image area is 40 .mu.m.
Read with a width of 5 μm. Therefore, in both semiconductor chips, there are document areas to be partially overlapped for reading, and the resolution in the main scanning direction is not exactly twice the original resolution. However, in practice, this method can sufficiently enhance the resolution.

Further, as shown in FIG. 7, the distance L5 between the photoelectric conversion element P of the semiconductor chip 4a and the photoelectric conversion element of the semiconductor chip 4b is 5 times the size = 50 μm of the photoelectric conversion element P in the sub-scanning direction. However, the value of the interval L5 is preferably 5 to 7 times the photoelectric conversion element size. The reason is that when the magnification is 4 times or less, the semiconductor chips are too close to each other to be physically arranged, and when the magnification is 8 times or more, the optical path passes around the lens, and the resolution is reduced.

Further, in this embodiment, the reduction ratio is 1 / 2.5, but if the reduction ratio is 1 / 1.25 using the same lens and the same photoelectric conversion device, one row of photoelectric conversion devices is obtained. Only 16 dots / mm can be read.
However, in this case, the sensitivity of the photoelectric conversion element is lowered because the amount of light incident on each element is reduced. In order to compensate for this decrease in sensitivity, it is necessary to increase the light amount of the illumination light source, but this increases the current consumption, which goes against the reduction in power consumption of the reading device. On the contrary, if the reduction ratio is too large, high resolution cannot be obtained. Therefore, in order to obtain sufficient sensitivity without increasing the current consumption of the light source, the reduction ratio is preferably in the range of 1/2 to 1/3.

Further, in this embodiment, the semiconductor chips 4a,
Although the reading device having 4b and one lens has been described, it goes without saying that a line type reading device in which a plurality of lenses and semiconductor chips are arranged may be used. Alternatively, a Selfox lens array (SLA), a roof mirror lens array, or the like may be used as the other optical system.

[0029]

As described above, according to the present invention, by reading and using a pair of semiconductor chips arranged in parallel at the same time, it is possible to obtain a high-resolution reading device without lowering the reading speed. Moreover, since the conventional semiconductor chip can be used as it is without changing the design of the semiconductor chip, a low-cost reading device can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view of a reading unit 31 of a reading device of the present invention.

2 is an X-X of the reader unit 31 shown in FIG.
It is a fragmentary sectional view which followed the disconnection.

FIG. 3 is a partial cross-sectional view of the reading device unit shown in FIG. 1, taken along the line YY.

FIG. 4 is an enlarged plan view of a semiconductor chip 4.

FIG. 5 is a circuit diagram showing an electrical configuration of a semiconductor chip 4.

6 is a time chart of each signal in the circuit diagram shown in FIG.

FIG. 7 shows semiconductor chips 4a, 4 of the reading device unit 31.
It is a layout of b.

FIG. 8 is a diagram for explaining a case where a document is read using the reading device unit 31 shown in FIG.

FIG. 9 is a perspective view of a conventional reading device unit 1.

10 is an XX of the reading device unit 1 shown in FIG.
It is a fragmentary sectional view which followed the disconnection.

11 is a partial cross-sectional view of the reading device unit shown in FIG. 9 taken along the line YY.

FIG. 12 is a perspective view of a reader equipped with a conventional reader unit 1.

FIG. 13 is a diagram for explaining a case where a document is read using the reading device shown in FIG.

FIG. 14 is a partially enlarged view of a conventional semiconductor chip 4.

[Explanation of symbols]

 4a, 4b Semiconductor chip 31 Reader unit 32 Light source 33 Lens 35 Substrate 37 Housing

Claims (2)

[Claims] 1. A pair of semiconductors having an optical system for forming reflected light from a document to form a document image, and a plurality of photoelectric conversion elements arranged in a line for receiving the document image. A reader comprising a chip, wherein the pair of semiconductor chips are arranged such that the photoelectric conversion element rows are parallel to each other in the main scanning direction,
A reading device, wherein one semiconductor chip is arranged so as to be displaced from the other semiconductor chip by ½ of a photoelectric conversion element pitch in the main scanning direction. 2. The reading device according to claim 1, wherein the distance between the one semiconductor chip and the other semiconductor chip in the sub-scanning direction is an integral multiple of the photoelectric conversion element size in the sub-scanning direction.