JPH0736593B2 - Contact image sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a structure of a contact image sensor.

[Outline of Invention]

According to the present invention, in a contact type image sensor, a plurality of photodiode array chips each having a scanning circuit formed on the same chip are mounted in a cascade connection, so that effects such as cost reduction, realization of a large-sized sensor, and ease of manufacturing are achieved. Is to have.

[Conventional technology]

Conventional Example 1 As shown in Japanese Patent Application Laid-Open No. 59-229968, the photodiode and the scanning circuit are composed of separate chips and wire-bonded.

Conventional Example 2 As shown in Japanese Patent Application Laid-Open No. 59-86363, CCD chips are arranged in a staggered pattern and optically imaged so as to be the same chip in operation.

[Problems and Objectives to be Solved by the Invention]

However, in the conventional example 1, the cost of the scanning circuit having a different chip configuration, which requires a plurality, and the mounting cost such as wire bonding are heavy, and the cost is high. Further, the conventional example 2 has a problem that the cost of the optical imaging element and the mounting adjustment cost of the optical imaging element are heavy and the cost is high.

Therefore, the present invention solves such a problem, and an object of the present invention is to reduce the cost of a contact image sensor, thereby to realize a large-sized sensor, and to provide a structure of the contact image sensor which is easy to manufacture. It is in the place of providing.

[Means for solving problems]

The contact image sensor of the present invention includes a plurality of sensors arranged on a straight line at equal intervals, and first and second scanning circuits each of which includes a scanning circuit that sequentially scans the plurality of sensors based on a clock input and a start pulse. A contact type having an image sensor chip and a mounting substrate for connecting the first and second image sensor chips, and scanning the second image sensor chip after the scanning of the first image sensor chip is completed. In the image sensor, dummy sensors respectively provided at positions different from the plurality of sensors arranged on the straight line on the first and second image sensor chips at equal intervals, and the first and second images. And means for invalidating the output signal from the dummy sensor scanning from the output signal obtained from the sensor chip and performing continuous data output. And it features.

[Action]

According to the above configuration of the contact image sensor of the present invention,
A plurality of image sensor chips can be handled like a single chip. Optically, the sensors are arranged on the same straight line at equal intervals, so that the SELFOC lens array or the like used in the first conventional example can be used. That is, by arranging the dummy sensor at a position different from the plurality of sensors arranged on a straight line at equal intervals and performing effective video output, the plurality of image sensor chips can be continuously arranged. As a result, the influence of the undetectable region by the dummy sensor can be eliminated when the image sensor chips are connected, so that the image sensor chips can be operated as if they were a single image sensor despite the connection of the plurality of image sensor chips. The effective video signal can be output as continuous data by means of invalidating the output signal of the dummy sensor scan.

〔Example〕

FIG. 1 is a mounting view of a contact image sensor according to an embodiment of the present invention. Image sensor chips S1, S2, and S3 are mounted on a mounting board 103 and are connected by bonding wires 105. The video output terminals VID of the image sensor chips S1 and S2 and the video output terminals VID of the image sensor chips S2 and S3 are connected via the mounting substrate 103, respectively. The end pulse terminal EP of the image sensor chip S1 and the start pulse terminal SP of the image sensor chip S2, and the end pulse terminal EP of the image sensor chip S2 and the start pulse terminal SP of the image sensor chip S3 are connected through the mounting board of 103, respectively. Has been done. The mounting board 10 is respectively connected to the sensor bias terminal VBB, the clock input terminal group 104 and the start pulse terminal SP of the image sensor chip S1.
Peripheral circuits are connected via 3. The clock etc. input terminal group 104 also includes a power supply terminal of the scanning circuit 101.

Image sensor chips S1, S2, S3 are video output terminal VID, sensor bias terminal VBB, clock, etc., which are symmetrically provided (start pulse terminal SP, end pulse terminal EP are omitted) at both ends in the long side direction of the chip. It is provided with a terminal group 104, a scanning circuit 101, a switch array 102, and photodiodes D1 to D99.

The image sensor chips S1, S2, S3 are mounted on the mounting substrate 103 such that the photodiodes D1 are omitted and the photodiodes Dn are located on a straight line at equal intervals.

FIG. 2 is a circuit diagram of the contact image sensor according to the embodiment of the present invention. S.CK is a sensor clock terminal, FFn is a flip-flop, NORn is a NOR gate, and SWn is a switch element. In FIG. 2, only the image sensor chips S1 and S2 are shown. Flip-flop FFn, NOR gate NOR
The scanning circuit 101 is composed of n and inverters.

FIG. 3 is an operation waveform diagram of the contact image sensor according to the embodiment of the present invention. Similar to FIG. 2, FIG. 3 shows the case of only the image sensor chips S1 and S2.
The system clock CK is commonly given to the image sensor chips S1 and S2. When the start pulse SP is given to the image sensor S1 while the system clock is being supplied, the start pulse SP is sequentially transmitted to the flip-flops FF1, FF2, ... According to the system clock CK. As a result, the NOR gates NOR1, NOR2, ... Are sequentially activated, and SW1, SW2 ,. As a result, the photodiodes D1, D2, ... Are sequentially scanned or selected (selection pulse). After the last photodiode D99 is selected, the start pulse SP that has passed through the NOR 100 passes through a delay circuit formed by connecting a plurality of inverters, and is output as an end pulse EP. This end pulse EP becomes the start pulse SP of the second image sensor S2. The start pulse and the end pulse generate noise in the video signal due to the stray capacitance with the video signal line. At the timing of the start pulse SP and end pulse EP surrounded by the dotted line, the video signal becomes an invalid output. S.CK is a sensor clock, and the start pulse SP is read at the rising edge of the waveform. Image sensor chip S1
In S1-NOR1 to S1-NOR99, and in the image sensor chip S2, time-sequential selection pulses of the switching elements SWn from S2-NOR1 to S2-NOR99 are generated. Stray capacitance (switch element SWn for the video signal line from the rising and falling waveforms of adjacent selection pulses)
(Including the gate capacitance of) is almost balanced, so the noise generated in the video signal is suppressed. However, the selection pulses S1-NOR1, S1-NOR99, S2-NOR1, S2-NOR9
At the timing surrounded by the dotted line of 9, there is no selection pulse that suppresses noise, so the video signal becomes an invalid output.

UID is a video signal waveform, from S1-D2 to S1-D99, S2-D
2 to S2-D99 are valid outputs. This is a photodiode arranged in a straight line at equal intervals in FIG.
Since it hits all of Dn, all necessary sensor signals are valid video output signals. The integrated waveform is obtained by integrating the video signal for each sensor output, and has an invalid output period as shown in FIG. Noise caused by the start pulse SP and invalid area scan output due to the scanning of the dummy sensor D1 are invalidated by a data latch circuit and a data selector circuit described later. Image sensor chip for continuous data output
This shows that if the video output of S1 is delayed by two clock cycles, a continuous and effective output can be obtained.

FIG. 4 is a system block diagram of the contact image sensor according to the embodiment of the present invention. When the start pulse SP and the clock CK are input to the timing generator 403, a control signal required for each block is generated. Croff buffer 405
From the sensor clock S.CK to the image sensor chips S1, S2,
The start pulse SP is given to the image sensor chips S1, S2 and S3. The video signals of the image sensor chips S1, S2, S3 are amplified by the preamplifier 407 and integrated by the integrator 408 for each sensor output. The integrated output is amplified by the buffer amplifier 409 and converted into a digital signal by the A / D converter 401. A / D converted digital signals are data latches R1, R2 and data selector 402
Is converted to continuous data by the continuous data output terminal 40
Output to 4. The procedure for converting to continuous data is as follows. While the video output of the image sensor chip S1 is being output, the output of the data latch R2 (data selector 1) is selected by the data selector 402, and while the video output of the image sensor chip S2 is being output, While the output of the latch R1 (data selector 2) is selected by the data selector 402 and the video output of the image sensor chip S3 is being output, the output of the A / D converter (data selector 3) remains unchanged. Selected by.

Invalid output and start pulse SP by selecting dummy sensor D1
The noise due to can be cut by the selection timing of the data selector, and continuous data output composed of effective sensor output can be obtained.

〔The invention's effect〕

As described above, according to the present invention, a contact image sensor having a long number of sensors can be obtained by mounting a plurality of image sensor chips on a mounting substrate. In other words, by arranging the dummy sensor outside the straight line where multiple sensors are arranged, the non-detection area by the dummy sensor can be eliminated, and the invalid output due to the dummy sensor selection can be eliminated, and continuous data as if it were one sensor. You can get the output. Even if a plurality of image sensor chips are used, only one signal processing system such as a preamplifier is required, and therefore, the cost of peripheral circuits can be reduced. Since the structure is simple and the cost is low, a large-sized sensor can be easily realized in terms of manufacturing and cost. Since no special processing is performed in terms of circuitry and optics, it has the effect of high reliability.

[Brief description of drawings]

FIG. 1 is a mounting view of the contact image sensor of the present invention. FIG. 2 is a circuit diagram of the contact image sensor of the present invention. FIG. 3 is an operation waveform diagram of the contact image sensor of the present invention. FIG. 4 is a system block diagram of the contact image sensor of the present invention. 101 …… Scan circuit 102 …… Switch array Dn (n = 1,2,3 …… 99) …… Photodiode S1, S2, S3 …… Image sensor chip VID …… Video output terminal EP …… End pulse terminal 103 …… Mounting board 401 …… A / D converter R1, R2 …… Data latch 402 …… Data selector 403 …… Timing generator

Claims (1)

[Claims] 1. A first image sensor chip and a second image sensor chip, each of which includes a plurality of sensors arranged on a straight line at equal intervals, and a scanning circuit which sequentially scans the plurality of sensors based on a clock input and a start pulse. A mounting substrate for connecting the first and second image sensor chips to each other, and the second substrate after completion of scanning of the first image sensor chip.
In the contact type image sensor configured to scan the image sensor chip, the plurality of sensors arranged on the straight line on the first and second image sensor chips at different positions are provided respectively. A contact image sensor, comprising: a dummy sensor; and means for invalidating an output signal obtained by scanning the dummy sensor from output signals obtained from the first and second image sensor chips and performing continuous data output. .