TWI445402B - Image sensor - Google Patents

Description

Image sensor

The present invention relates to an image sensor, and more particularly to a line type image sensor.

Contact image sensor (CIS) has been widely used in scanners, photocopiers and fax machines. Contact image sensor modules are used to sense documents to be scanned or to be scanned. The electronic components can be typed in words such as text, photos and pictures.

In the process of scanning the paper document, the contact image sensor module first integrates the first line of the file, and after reading the first line of the file, the contact image sensor module sends a signal to the step. After entering the motor, the stepping motor will drive the roller after receiving the signal until the second line of the document enters the reading area of the contact image sensor module, and the contact image sensor module continues to read the file. Two lines, repeat the steps until all the lines on the file have been read.

FIG. 1 shows a schematic structural view of a conventional image sensor 10. The conventional image sensor 10 is mainly formed by arranging a plurality of sensing wafers 11 and 12 in a strip, and each of the sensing wafers 11 and 12 is provided with a plurality of pixel units 15 in a row. The pixel unit 15 is configured to sense images to generate image data, and the pixel units 15 located on the different sensing wafers 11, 12 are also aligned. The pixel unit 15 of this column can sense one line of the file at a time to generate image data corresponding to one line of the file.

In the conventional image sensor 10, a gap is left between the two sensing wafers 11, 12, so that the pitch of the adjacent pixel units 15 between the two sensing wafers 11, 12 and the general pixel unit 15 The spacing is inconsistent, even exceeding the spacing of the general pixel unit 15, resulting in defects in the scanned image. In severe cases, the scanned image will have a distinct thin line.

It is conservatively estimated that the distance D of the first pixel unit 15 of the sensing wafer 11 to the last pixel unit 15 of the sensing wafer 12 is at least 20+2+5+5+5+2=39 um, still The distance D2 of the two pixel units 15 when the resolution is 1200 DPI is exceeded, that is, 21.16 um. Even in the worst case, the distance D is at most 20+2+10+15+10+2=57 um, and there are fewer than two pixel widths in the middle. It can be seen that the gap between the two sensing wafers 11 and 12 has a great influence on the quality of the scanned image, and may be a serious problem if the design is poor.

Figure 2 shows a schematic diagram of a conventional pixel reading architecture. Each pixel unit 15 has a photodiode 22, an amplifier 24, a transistor switch 26, and a reset transistor 28. The photodiode 22 is configured to sense an optical signal to generate a current signal representative of the image data. The current signal is used to enhance the signal intensity through the amplifier 24, and the transistor switch 26 can control the output of the image data, and the reset transistor 28 is used to Set (offset) or clear the data.

By applying a control signal on the control line 201, the transistor switch 26 in each pixel unit 15 is sequentially turned on to sequentially read the image data generated by the photodiode 22, and the image data is output via the pixel data line 202. . However, the image data generated by the photodiode 22 in the conventional pixel reading architecture is a one-way output, thereby limiting the diversity of the arrangement design of the sensing wafers 11, 12 or the pixel unit 15, and cannot solve the two The problem of poor scanning image quality caused by the gap between the wafers 11 and 12 is sensed.

Therefore, how to improve the quality of the scanned image caused by the gap between the sensing wafers is an urgent problem to be solved in the industry.

It is an object of the present invention to provide an image sensor that solves the problem of poor quality of scanned images caused by sensing gaps between wafers.

According to the foregoing objective, the present invention provides an image sensor comprising: a first sensing chip; and a second sensing chip, wherein each of the two sensing chips is provided with a plurality of pixel units in a row, The pixel unit is configured to sense an image to generate image data, wherein the pixel unit in the first sensing chip is offset from the pixel unit in the second sensing chip and belongs to two columns, and the pixel A portion of the pixel unit in the sensing wafer is at the same column position as a portion of the pixel unit in the second sensing wafer.

Since the pixel units of the first sensing chip and the second sensing wafer overlap each other at the same edge or at the same column position, all the pixel units in the two sensing wafers are in the column direction. With the same spacing, there is no obvious spacing between the two sensing wafers in the column direction, so the scanned image quality is better, and there is no thin line, so the scanning image caused by the gap between the two sensing wafers can be solved. The problem of poor quality.

The image sensor of the present invention is configured by arranging at least one sensing wafer of a long strip type image sensor horizontally by 180 degrees, and the pixel of the rotated sensing wafer and other sensing wafers The cells are arranged in two columns, and some pixel cells are located at the same column position, thereby overcoming the problem of poor scanning image quality caused by the gap between the two sensing wafers.

FIG. 3 is a block diagram showing the structure of an image sensor 30 implemented in accordance with the present invention. The image sensor 30 of the present invention includes a plurality of sensing wafers 31, 32, 33. Each of the sensing chips 31, 32, 33 is provided with a plurality of pixel units 35 in a row, and the pixel units 35 are used to sense images to correspondingly generate image data.

As shown in FIG. 3, the pixel units 35 in the first sensing wafer 31 are offset from the pixel units 35 in the second sensing wafer 32 and are divided into two columns, and the pixels in the first sensing wafer 31 are included. The unit 35 is offset from the pixel units 35 in the third sensing wafer 33 and belongs to two columns, and the pixel unit 35 in the second sensing wafer 32 is in the same state as the pixel unit 35 in the third sensing wafer 33. Column.

A portion of the pixel unit 35 in the first sensing wafer 31 is located at the same column position as a portion of the pixel unit 35 in the second sensing wafer 32, and the first sensing wafer 31 has another The partial pixel unit 35 is located at the same column position as a portion of the pixel unit 35 in the third sensing wafer 33. It should be noted that the column position herein refers to the positioning of one-dimensional coordinates, and the same column position refers to having substantially the same coordinate value when positioned by one-dimensional coordinates.

The pixel units 35 at the end edges of the first sensing wafer 31, the second sensing wafer 32, and the third sensing wafer 33 overlap each other or at the same column position. For example, the pixel unit 35 at the end of the first sensing wafer 31 is aligned with the pixel unit 35 of the first segment of the second sensing wafer 32, and the pixel unit 35 of the first segment of the first sensing wafer 31 is The pixel units 35 at the end of the third sensing wafer 33 are arranged in a row. It should be noted that the number of pixel units 35 overlapping the first segment and the last segment is not limited, but preferably, one or two pixel units 35 may be overlapped. If the number of overlapping pixel units 35 is one, the last pixel unit 35 in the first sensing wafer 31 is aligned with the first pixel unit 35 in the second sensing wafer 32, or The first pixel unit 35 in the first sensing wafer 31 is aligned with the last pixel unit 35 in the third sensing wafer 33.

The two column pixel units 15 of the first sensing wafer 31, the second sensing chip 32, and the third sensing wafer 33 arranged as above can sense one line of the file at a time to generate an image corresponding to one line of the file. The image data generated by each pixel unit 15 is sequentially read in the same direction.

In the present invention, since the pixel units 35 at the end edges of the first sensing wafer 31, the second sensing wafer 32, and the third sensing wafer 33 overlap each other or at the same column position, the column direction is In other words, all of the pixel units 35 in the sensing wafers 31, 32, and 33 have the same pitch, and there is no significant spacing between the two sensing wafers in the column direction, so the scanned image quality is better, and the image quality is not improved. There is a thin line, so the problem of poor scanning image quality caused by the gap between the two sensing wafers can be solved.

It should be further noted that the image data generated by the pixel units 35 overlapping each other or at the same column position can be corrected by software, for example, the image data generated by the two overlapping pixel units 35 are equally calculated. , take the average output of the two.

In addition, each of the sensing wafers 31, 32, and 33 in the image sensor 30 of the present invention has an identification point 36 and a control unit 38. Each of the identification points 36 can be used as an implement for aligning and aligning the sensing wafers 31, 32, and 33. When each of the sensing wafers 31, 32, and 33 is disposed, the sampling camera of the implement can calculate the distance according to each of the identification points 36. Each of the sensing wafers 31, 32, 33 is placed, so that the pixel units 35 can be accurately arranged and arranged at the same column position, and the distance of the overlapping pixel units 35 can be appropriately controlled, and the error can be controlled. Within the range of ±7um.

In addition, each of the sensing wafers 31, 32, 33 in the image sensor 30 of the present invention has a control unit 38. Each control unit 38 is configured to control the reading order of the image data generated by the respective pixel units 35 in each of the sensing wafers 31, 32, 33, and to sense all the pixels in the wafers 31, 32, 33. The image data generated by unit 35 is sequentially read in the same direction.

In addition, each of the sensing wafers 31, 32, and 33 in the image sensor 30 of the present invention may be the same sensing wafer, or a sensing wafer of the same specification, or a compatible sensing wafer, with different specifications but different phases. A capacitive sensing wafer can also be implemented.

Figure 4 shows a schematic diagram of a pixel reading architecture implemented in accordance with the present invention. Each pixel unit 35 has a photodiode 42, an amplifier 44, a transistor switch 46, and a reset transistor 48. The photodiode 42 is used to sense the optical signal to generate a current signal representing the image data. The current signal is used to gain the signal intensity through the amplifier 44. The transistor switch 46 can control the output of the image data, and the reset transistor 28 is used to Set (offset) or clear the data.

As shown in FIG. 3 and FIG. 4, the control unit 38 in the image sensor 30 of the present invention generates a control signal transmitted through the control line 201, and the control signal is a signal having a high level and a low level alternately. When the control signal is at a high level, the transistor switch 46 can be turned on to output image data generated by the photodiode 42, and when the control signal is at a low level, the transistor switch 46 is turned off, and no image data is output at this time. It should be noted that the image data generated by the photodiode 42 is transmitted via the pixel data line 402.

The control signal generated by the control unit 38 sequentially turns on the transistor switch 46 in each pixel unit 35 to sequentially read the image data generated by the photodiode 42. The control signal generated by the control unit 38 can be transmitted in different directions on the control line 401, that is, the control signal can be input in both directions, and the control signal can control the image data to be sequentially read in a first direction, and can also control the image data to The second direction is reversed in the first direction, that is, the image data generated by the photodiode 42 can be selected to output in one of two directions, and has the characteristics of bidirectional output.

Since the image data generated by each of the sensing wafers 31, 32, and 33 has a bidirectional output characteristic, the arrangement of each of the sensing wafers 31, 32, 33 or the pixel unit 35 is limited in design, and the image data can be satisfied. The requirement that the directions are sequentially read out, the linear structure in which the sense wafers are rotated 180 degrees horizontally (such as the first sensing wafer 31) can be supported and implemented.

In view of the above, the present invention has been disclosed in the above preferred embodiments, and is not intended to limit the invention, and the present invention may be made without departing from the spirit and scope of the invention. Various modifications and refinements are made, and the scope of the present invention is defined by the scope of the appended claims.

10. . . Conventional image sensor

11. . . Sense wafer

12. . . Sense wafer

15. . . Pixel unit

twenty two. . . Photodiode

twenty four. . . Amplifier

26. . . Transistor switch

28. . . Reset transistor

30. . . Image sensor

31. . . First sensing chip

32. . . Second sensing chip

33. . . Third sensing chip

35. . . Pixel unit

36. . . Identification point

38. . . control unit

42. . . Photodiode

44. . . Amplifier

46. . . Transistor switch

48. . . Reset transistor

201. . . Control line

202. . . Pixel data line

401. . . Control line

402. . . Pixel data line

D, D1~D5. . . distance

Figure 1 shows a schematic diagram of the structure of a conventional image sensor.

Figure 2 shows a schematic diagram of a conventional pixel reading architecture.

Figure 3 is a block diagram showing the structure of an image sensor according to the present invention.

Figure 4 shows a schematic diagram of a pixel reading architecture implemented in accordance with the present invention.

30. . . Image sensor

31. . . First sensing chip

32. . . Second sensing chip

33. . . Third sensing chip

35. . . Pixel unit

36. . . Identification point

38. . . control unit

Claims (9)

An image sensor includes: a first sensing chip; and a second sensing chip, wherein each of the two sensing chips is provided with a plurality of pixel units in a row, the pixel units are used Sensing the image to generate the image data, wherein the pixel unit in the first sensing chip is offset from the pixel unit in the second sensing chip and belongs to two columns, and the first sensing chip is in the last stage. The pixel unit is arranged in parallel with the pixel unit of the first segment in the second sensing wafer. The image sensor of claim 1, further comprising: a third sensing chip, wherein a plurality of pixel units in a row are arranged, wherein the pixels in the first sensing chip The cells are offset from the pixel units in the third sensing chip and are divided into two columns. The first pixel unit in the first sensing chip is arranged in parallel with the pixel unit in the last sensing chip. The image sensor of claim 1, wherein the last pixel unit in the first sensing wafer is aligned with the first pixel unit in the second sensing wafer. The image sensor of claim 1, wherein each of the two sensing chips has a control unit for controlling the reading order of the image data generated by the respective pixel units in the two wafers. The image sensor of claim 4, wherein the image data generated by the pixel units in the two sensing wafers are sequentially read in the same direction. The image sensor of claim 4, wherein the control unit controls the reading order of the image data by transmitting a control signal having a high level and a low level alternately. The image sensor of claim 4, wherein the control unit can control the image data to be sequentially read in a first direction, and can also control the image data to be in a second direction opposite to the first direction. read out. The image sensor of claim 1, wherein each of the two sensing wafers The utility model has an identification point for arranging and aligning the two sensing chips. The image sensor of claim 1, wherein the two sensing chips are the same sensing wafer.