JPH047954A - Close contact type linear image sensor module - Google Patents

Abstract

PURPOSE:To improve the stability as a reference level by adopting a structure such that a specific picture element is already shut in a module single body so as to obtain a complete dark state output. CONSTITUTION:Plural picture elements are shielded at the left end of an image sensor module in which sensor chips 12 each comprising 10 picture elements are mounted. As the means of a light shield, a light shield object 13 is formed by placing any light shied object such as an IC onto a picture element or a black resin. Thus, an output signal of a dark part is used as a basis to calibrate a reference level and sensitivity or the like to make an incident luminous quantity to each picture element accurately and the picture reading of a high resolution image scanner or the like is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure of a contact type linear image sensor module in which several image sensor semiconductor chips are mounted on a circuit board.

[Summary of the invention]

This invention provides a close-contact image sensor module in which an image sensor semiconductor chip is mounted on a circuit board, by preventing light from hitting some pixels, so that the sensor is always in a pitch-dark state from the pixels. By using this signal to calibrate the reference level and sensitivity, the amount of light incident on each pixel can be accurately determined, making it possible to use image reading devices such as high-resolution image scanners. This has been made possible.

[Conventional technology]

The third recessed hole is a side view showing a structure around an image sensor module of a conventional image scanner. Also, the third
In other words, the third recessed hole is concave in cross section A-A. In the conventional example shown here, the two unit guide holes 6 are guided by the rod of the unit guide, and the image sensor
is an example of a fixed document image scanner that moves in the front and back directions of the paper surface. In this example, an original is set on the original table 5 so as to face the image sensor unit 1-1 (face down), and the original is illuminated by the light a8 and drawn on the original. Reflected light corresponding to the image is guided to the sensor search 7 through the SELFOC lens array 4. Thereby, the sensor chip 2 is configured to generate an electrical signal corresponding to the image of the reflected light, and transmit this to the control circuit of the image scanner to read the image.

In conventional high-resolution image scanners with such a configuration, in order to obtain the output in pitch darkness (reference output) described above, the image sensor reading range (image A black plate-shaped male reference plate 7 is placed at the same height as the document surface outside the area (in the main scanning direction that is captured as information), and even if light hits this plate, there is almost no reflected light, so This is the output when it is completely dark (hereafter,
(abbreviated as dark output), and using this as a reference output level, signal processing is performed to calibrate the actual image output portion.

[Problem to be solved by the invention]

However, the conventional method as described above has the following problems.

■The black reference plate not only does not provide a complete dark output due to a small amount of reflected light, but also has a problem with its stability as a reference level, as the amount of reflected light also varies slightly due to variations in the black tone.

■Where and where do the pixels of the contact linear image sensor module go? A. Compatibility with the reference plate is determined by the relative positional relationship between the black reference position and the contact type linear image sensor module, but the relative positional relationship between the two depends on the mechanical positioning accuracy of each other. Because it depends on the synergistic accuracy of both, it is necessary to strictly control the mechanical positioning accuracy of both. Furthermore, if positional deviation between the two is allowed, it is necessary to provide a wider area for the black reference, resulting in an increase in wasted space.

[Means to solve the problem]

In order to solve the above problems, the present invention has a structure in which a specific pixel of a contact type linear image sensor module is already shielded from light when the module is alone.

[Effect]

The close-contact linear image sensor module configured as described above is: (1) By using a method that allows the light blocking means to completely block light, the output of the pixel can be completely dark; In addition to improving the stability as a reference level, ■By accurately managing the light-shielding area and performing it at the time of module mounting, it is possible to improve the mechanical It becomes possible to accurately determine the position regardless of the actual positioning.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

The first recessed hole is shown in FIG.
is its side view. In this embodiment, seven sensor chips 12 each having 10 pixels are placed on a sensor substrate 11.
This shows an image sensor module that is individually mounted, and is an example in which light is shielded from the leftmost pixel to the third pixel.

Here, an example is shown in which the light-shielding object 13 is made of black resin as a light-shielding means, but it goes without saying that the same effect can be obtained by placing some kind of light-shielding object such as an IC on top of the pixel. .

In this example, the first to third pixels from the left, that is,
The configuration is such that after three pieces of dark output level data are output, the original image output is obtained from the fourth pixel onwards.

In a device configured in this way, if the average value of the output levels from the first pixel to the third pixel is X volts, and the output of the fourth pixel is y volts, then the image scanner circuit will be
-X volts is set as data for the fourth pixel, and data for the fifth and subsequent pixels are obtained in the same manner.

Next, the necessity of data processing will be explained.

FIG. 2 is a graph showing dark output on the vertical axis and temperature on the horizontal axis. As shown in the figure, as the temperature increases, the dark output also tends to increase. However, the rate of increase in dark output as the temperature rises varies depending on the workpiece. Furthermore, the temperature rise of the image sensor module when used in an image scanner also varies depending on the state of use. In addition, the bright output (output of pixels that receive reflected light from the original) is output with the output due to light energy added to the dark output, so the bright output becomes almost the dark output as the temperature rises. The output increases by an amount commensurate with the increase. therefore,
If the image data is the value obtained by subtracting the dark output from the bright output, then
This means that the output characteristics due to the ambient temperature and the software component can be offset.

In the actual operation of an image scanner, the temperature drift is large because the system is not in a thermal equilibrium state immediately after power is turned on. Furthermore, depending on the image scanner's built-in memory and the processing capacity of the host computer, the image scanner may temporarily stop during image reading (so-called busy control). In such a case, the data will have a certain time difference in the middle of the image. The sensitivity of human vision is quite sharp in these adjacent areas, and even a small difference can be recognized, so uniformity of sensitivity within one screen is strictly required, and even the slightest temperature difference before and after busy control will affect the image quality.

Therefore, management with such strict accuracy is particularly important for color scanners.

〔Effect of the invention〕

As explained above, according to the present invention, by preventing light from hitting some pixels of an image sensor semiconductor chip mounted on a circuit board, a reference level is set based on the output signal of this pitch-black area. , sensitivity, etc. are calibrated, thereby accurately grasping the amount of light incident on each pixel, and has the effect of realizing a high-resolution image reading device such as an image scanner.

[Brief explanation of drawings]

FIG. 1 is a diagram of an image sensor module showing an embodiment of the present invention, where the round part is a plan view and the part (■) is a side view. Second
The figure is a graph showing the relationship between dark output on the vertical axis and temperature on the horizontal axis. FIG. 3 is a diagram showing the structure around the image sensor unit of a conventional image scanner, where the cross section is a side view and the cross section is a cross-sectional view taken along the line A--A of the cross section. SELFOC lens array manuscript table, Unisotosite hole, black reference plate, light source, light-shielding object or more Applicant Seiko Electronics Co., Ltd. Agent Patent attorney Keisuke Hayashi 1...Image sensor unit 2...Sensor chimp 3... Sensor board diagram (A) Dark work V diagram

Claims (4)

[Claims] (1) The main components are a circuit board and an image sensor semiconductor chip, and there are N pieces on the circuit board (N is a natural number of 1 or more).
In a close-contact linear image sensor module mounted with an image sensor semiconductor chip, some specific sensing pixels (hereinafter simply referred to as pixels) are masked to prevent light from entering. Features a close-contact linear image sensor module. (2) The contact type linear image sensor module according to claim 1, wherein the image sensor semiconductor chip is a color image sensor semiconductor chip in which a color filter is attached to an IC chip. (3) The contact type linear image sensor module according to claim 1, wherein the pixel is masked by covering the pixel with a black resin. (4) The contact type linear image sensor module according to claim 1, wherein N pixels (N is a natural number of 1 or more) are masked from the left end or right end of the module.