JPH0740715B2 - Image reading sensor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an image reading sensor for photoelectrically reading an image.

[Conventional technology]

For reading original images on digital copiers and fax machines
Arranging multiple linear image sensors on a single substrate,
As a result, a contact-type multi-chips near-line image sensor that can read a document one-on-one has been proposed.

As shown in FIG. 4, the contact type multi-chip linear image sensor proposed in the related art connects short linear image sensor chips 1 to 5 by a length sufficient to cover the main scanning length of the original. For this purpose, a long ceramic substrate
11, the linear image sensor chips 1 to 5 described above are formed on a continuous conductive land pattern 7 formed on the substrate 11.
Was attached by soldering and was manufactured as one piece.

That is, in FIG. 4, 1 to 5 each have a large number of photosensitive pixels arranged in a straight line, and each CCD linear image sensor chip which outputs an image signal in accordance with the incident amount, and 6 a CCD A long ceramic board for integrating the linear image sensor chips 1 to 5, 7 is an individual CCD linear image sensor chip provided on the ceramic board 6 is mounted on the ceramic board 6, and each CCD is mounted.
Conductive land patterns for supplying power to the linear image sensor chips 1 to 5, 8 is an externally applied sensor drive pulse or individual sensor to drive the independent CCD linear image sensor chips 1 to 5, respectively. The conductive pattern provided on the ceramic substrate 6 for taking out the image signal output by the device 9 terminates the conductive pattern 8 on the ceramic substrate 6, and each signal from the ceramic substrate 6 to the outside and to the outside. It is a terminal land for transmitting.
FIG. 5 shows an enlarged view of a portion surrounded by a circular frame in FIG. In FIG. 5, 10 is a bonding wire for driving the independent linear image sensor chips 1-5 or for connecting the outputs from the linear image sensor chips 1-5 to the conductive pattern 8 on the ceramic plate. Is. Reference numeral 11 in FIG. 4 shows a contact type multi-chip linear image sensor composed of linear image sensor chips 1 to 5 and a ceramic substrate 6.

As shown in FIG. 4 and FIG. 5, the conventional contact type multi-chip linear image sensor 11 has independent linear image sensor chips 1 to 5 assembled on a conductive land pattern 7 on one ceramic substrate 6, Through the conductive pattern 8, the bonding wire 10 and the terminal land 9 on the ceramic substrate 6, the driving signals, the power supply, and the image signals to and from the respective independent linear image sensor chips 1 to 5 are exchanged with the outside. Then, the divided main scanning images independently output by the independent linear image sensor chips 1 to 5 are combined by an external device (not shown) to form one continuous main scanning image.

However, a plurality of linear image sensor chips 1 of this conventional contact-type multichip image sensor 11 are used.
When driving .about.5 in parallel, there is a problem of signal crosstalk in which the signals between the adjacent independent image sensor chips are slightly mixed with each other. If the original image reading device using this sensor is a binary image reading device that discriminates only white and black, this is not a problem because the black and white detection comparison signal level difference is large.
When an attempt is made to read a continuous gradation image from the white level to the black level of the original, the signal leakage between the adjacent independent image sensor chips significantly deteriorates the quality of the original image reading signal in the main scanning.

For example, as shown in FIG. 6, when a black-and-white signal obtained by scanning an original 12 having a black-and-white pattern having a clear signal contrast enters a linear image sensor chip 4, as shown in FIG. Independent linear image sensor chips 3 and 5 adjacent to the sensor chip 4 also show the wet signal of the signal V4 of the linear image sensor chip 4 called VR3, VR5. The signal wetting between the adjacent linear image sensor chips is caused by the ceramic substrate 6
This is because the conductive land pattern 7 for mounting the above linear image sensor chip contains a minute electric resistance. In FIG. 7, the wet signal of the signal V4 of the linear image sensor 4 appears only in the linear image sensors 3 and 5 because the linear image sensors 1 and 2 are spatially separated from the linear image sensor 4. Therefore, since the resistance value is large, the wetting signal of the signal V4 of the linear image sensor 3 is unlikely to appear in the linear image sensors 1 and 2, and the wetting signal of the signal V4 of the linear image sensor 3 does not appear in the linear image sensors 1 and 2. This is because the case where it has not appeared is shown.

A power supply equivalent circuit of the image sensor of FIG. 5 is shown in FIG. That is, since the power supply to each independent linear image sensor chip is performed by the supply line having a minute electric resistance between the adjacent sensor chips, a current caused by a change in the optical input signal to one independent image sensor chip is generated. The change becomes the power supply voltage change of the other independent image sensor chip.

Therefore, due to the minute resistance component existing in this common power supply line, power fluctuations due to image signal changes occur, and the image outputs of the independent independent linear image sensor chips are slightly mixed with each other. This caused the performance of the original image reading device to deteriorate.

〔Purpose〕

The present invention has been made in view of the above points, and an object of the present invention is to realize an image reading sensor that eliminates cross talk between chips in a contact type multi-chip linear image sensor and creates an image signal with high accuracy. .

〔Example〕

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

FIG. 1 shows the configuration of a contact type multi-chip purine image sensor 41 to which the present invention is applied. In FIG. 1, 31 to 35
Is a CCD linear image sensor chip that has a large number of photosensitive pixels arranged in a line and outputs an image signal according to the amount of incident light, and 36 is an integrated CCDR linear image sensor chip 31-35. Long linear ceramic substrate, 21 to 25 are independent CCD linear image sensor chips 31 to 35 provided on the ceramic substrate 36, and are individually mounted on the ceramic substrate 36, and each CCD linear image sensor chip is mounted. Conductive land patterns for supplying power to 31 to 35, and 38 are sensor drive pulses given from the outside to drive the independent CCD linear image sensor chips 31 to 35, and image signals output by each sensor. Conductive pattern provided on the ceramic substrate 36 for taking out the signal to the outside, 39 terminates the conductive pattern 38 on the ceramic substrate 36, and outputs each signal from the ceramic substrate 36 to the outside. Et al., Also is a terminal land for transmission to the outside. FIG. 2 shows an enlarged view of a portion surrounded by a circular frame in FIG. In FIG. 2, 40 is an independent linear image sensor chip 31 ...
The output from the linear image sensor chips 31 to 35 for driving 35 is set as the conductive pattern 38 on the ceramic board.
Bonding wire to connect to.

The contact-type multi-chip linear image sensor 41 shown in FIGS. 1 and 2 is provided with independent linear image sensor chips 31 to 35 electrically on one ceramic substrate 36 corresponding to each linear image sensor chip. Assembled on independent conductive land patterns 21 to 25, through the conductive pattern 38 on the ceramic substrate 36, the bonding wire 40, and the terminal land 39, the drive signals to the individual independent linear image sensor chips 31 to 35, and the power supply. , Exchange image signals with the outside. Then, the divided main scanning images independently output by the independent linear image sensor chips 31 to 35 are combined by an external device (not shown) to form one continuous main scanning image.

In this manner, the conductive land patterns 21 to 25 for mounting the sensor chips on the ceramic substrate 36 are electrically independent for each chip 31 to 35. That is, by forming a contact-type multi-chip linear image sensor with a configuration in which power is independently supplied to each linear image sensor chip as in the equivalent circuit shown in FIG. 3, it is possible to suppress fluctuations in power supply voltage between adjacent image sensor chips. is there.

In this embodiment, the contact type multi-chip image sensor in which the five linear image sensor chips are provided on the ceramic substrate is presented, but the present invention is not limited to this, and the linear scanning sensor may be used depending on the main scanning width to be read and the resolution. The number of image sensor chips and the length of each can be appropriately selected.

[Effect]

As described above, according to the present invention, power is not supplied to a plurality of linear image sensor chips on a single ceramic substrate through a common power supply line, but electrical power is supplied on a single ceramic substrate. Since a plurality of electrically conductive land patterns that are independent of each other are provided and the power can be independently supplied to the plurality of linear image sensor chips through each of the plurality of land patterns, the plurality of linear image sensors are driven in parallel. In this case, it is possible to eliminate the occurrence of crosstalk between the linear image sensor chips, which makes it possible to read a high quality original image having continuous gradation.

[Brief description of drawings]

FIG. 1 is a block diagram of a contact type multi-chips image sensor to which the present invention is applied, and FIG. 2 is a partially enlarged view of FIG.
FIG. 3 is an equivalent circuit diagram of FIG. 1, FIG. 4 is a configuration diagram of a conventional contact-type multi-chips image sensor, FIG. 5 is a partially enlarged view of FIG. 4, and FIG. 6 shows an example of an image. Figure, 7th
FIG. 8 is a diagram showing an output when the image shown in FIG. 6 is scanned by the contact type multi-chips image sensor shown in FIG.
The figure is an equivalent circuit diagram of FIG. 4, 21 to 25 are conductive land patterns, 31 to 35 are CCD linear image sensor chips, and 36.
Is a ceramic substrate and 39 is a terminal land.

Claims (1)

[Claims] 1. An image reading sensor comprising a plurality of linear image sensor chips on a single ceramic substrate, wherein the plurality of linear image sensor chips divide a main scanning area of an original to read. A plurality of electrically independent conductive land patterns are provided on the substrate, a linear image sensor chip is attached to each of the plurality of conductive land patterns, and a power source for driving the plurality of linear image sensor chips is externally provided. An image reading sensor, characterized in that it can be independently supplied from a power supply source to the plurality of linear image sensor chips via each of the plurality of land patterns.