JPS649790B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an image sensor used for reading a document in a facsimile machine or the like.

[Technical background of the invention and its problems]

A contact image sensor uses a 1-magnification imaging system such as a rod lens array to form and read an image on a document on a photoelectric conversion element array with a length that is approximately equal to the width of the document. Short (e.g. 17
mm), making it easy to downsize the device.
It is expected to be applied to facsimile devices, OCR, copying machines, etc.

However, it is technically and cost-effective to realize an image sensor with a photoelectric conversion element array as long as the width of an A4-sized document using a single chip such as a CCD, so a contact image sensor is used. When configuring this, a method is used in which multiple image sensor chips with an array length of several tens of millimeters are used side by side.

An example of such a contact type image sensor is an image sensor described in Japanese Patent Application Laid-open No. 129065/1983. Fig. 1 shows the outline of the system, and the image sensor chips 1a, 1b... are arranged in a staggered manner so that the photoelectric conversion element arrays 2a, 2b... are alternately located on two parallel straight lines 3, 4. Arranged. photoelectric conversion element array 2a,
The array length of 2b... is the image sensor chip 1a,
Since it is shorter than the length of 1b..., if the chips are arranged in a line, it becomes impossible to read the areas corresponding to both ends of the chips, but if the chips are arranged in a staggered manner, this problem is solved.

The photoelectric conversion element arrays 2a, 2b, . …
are arranged so that the arrays 2a, 2b, . . . face inward. In this way, the distance d between the lines 3 and 4 can be reduced, so that the image sensor chips 1a and 1 of the first row on the preceding line 3 in the sub-scanning direction Y
The information read by c... is stored in the memory, and the image sensor chips 1b and 1d in the second row on line 4
It is possible to reduce the memory capacity required to obtain one line of information by combining the information with the information read when the ... reaches the same line.

By the way, as each image sensor chip shown in FIG. 1, for example, a CCD image sensor as shown in FIG. 2 can be used. In Figure 2,
11 is a substrate, 12 is a photoelectric conversion element array such as a photodiode array, and the array 12 is arranged in a line near one side of the substrate 11. A charge storage section 13, a gate 14, and a charge transfer section 15 are sequentially provided adjacent to the photoelectric conversion element array 12, and charges corresponding to the amount of light incident on the photoelectric conversion element array 12 are temporarily accumulated in the charge storage section 13, and then the gate After being transferred in parallel to the charge transfer section 15 via the gate 14 opened by the pulse GP, the charge is transferred in series within the charge transfer section 15, and is converted into a voltage signal at the output section 16 to obtain the readout output Vout. It's becoming like that.

When the CCD image sensor of FIG. 2 is used as one image sensor chip and the staggered arrangement of image sensors of FIG. 1 is constructed, the result is as shown in FIG. 3. In other words, in the CCD image sensor as shown in FIG. 2, since the charge transfer direction A of the charge transfer section 15 is uniquely defined from the structure, the first row of chips 1a, 1c, . 2 rows of chips 1
When chips 1a, 1d, etc. are arranged so that the photoelectric conversion element array is located on the inside, the charge transfer direction in the arrangement state, that is, the reading scanning direction is the same as chips 1a, 1c.
...and the chips 1b, 1d... are reversed. Therefore, for example, chips 1a, 1d, etc. are connected to the output side of chips 1b, 1d, .
1c... A processing circuit 5 is required to match the reading scanning direction. This processing circuit 5 includes a memory having a capacity equivalent to the number of pixels read by one chip,
The configuration becomes quite complex.

[Purpose of the invention]

An object of the present invention is to match the reading scanning direction of each image sensor chip without adding a complicated processing circuit when image sensor chips in which a photoelectric conversion element array is arranged on one side of a substrate are arranged in a staggered manner. The objective is to provide an image sensor that can

[Summary of the invention]

The present invention is an image sensor chip of a type that serially transfers and outputs the charges of a photoelectric conversion element array arranged on one side on a substrate. Two types of image sensor chips are prepared, and these two
It is characterized in that the image sensor chips are arranged in a staggered manner so that the photoelectric conversion element arrays face inward and are located on two parallel straight lines.

Here, the meaning of making the transfer directions of the charge transfer parts different from each other means that when the first type and second type image sensor chips are placed in the same state,
This means that the uniquely defined transfer directions are opposite to each other.

〔Effect of the invention〕

According to this invention, when the first type and second type of image sensor chips are arranged in a staggered manner, each charge transfer direction, that is, the reading scanning direction is the same. Therefore, a complicated processing circuit for adjusting the reading scanning direction is not required, so the interval between the rows of the first type of image sensor chips and the rows of the second type of image sensor chips can be reduced, and the overall configuration is improved. can be greatly simplified.

The first type and second type of image sensor chips in which the charge transfer portions have different transfer directions can be easily realized, for example, by making their structures mirror image symmetry with each other.

[Embodiments of the invention]

Figures 4a and 4b are the first images used in this invention, respectively.
This figure shows an example of the first type and second type of image sensor chip, and is an example using a CCD image sensor. 11 is a substrate, and 12 is a photoelectric conversion element array consisting of a photodiode array or the like, and the array 12 is disposed toward the lower side of the substrate 11 in both a and b. A charge storage section 13, a gate 14, and a charge transfer section 15 are sequentially provided above the photoelectric conversion element array 12 in the figure.

Here, the charge transfer section 15 receives the charges of the photoelectric conversion element array 12 in parallel via the charge storage section 13 and the gate 14, as explained in FIG.
Serially transferred and read out via output section 16
Although it is taken out as Vout, the transfer direction is opposite between a and b as shown by arrows A and B.

The image sensor chips of FIGS. 4a and 4b have, for example, a mirror-symmetric structure, as described above, and thus have mutually opposite transfer directions A, B. Two types of image sensor chips with mirror image symmetry, e.g.
CCD image sensors can be realized by using the same mask inverted, so only one type of mask needs to be designed and the manufacturing process can be exactly the same. Therefore, the cost is the same as manufacturing one type of CCD image sensor, and the electrical characteristics are also the same.

FIG. 5 shows the first type and second type image sensor chips shown in FIGS. 4a and 4b, with the photoelectric conversion element array facing inward as shown in FIG. This figure shows the structure of an image sensor according to an embodiment of the present invention, which is arranged on a common substrate (sensor substrate) so as to be located above. As is clear from the figure, the reading scanning directions of the first row, that is, the first type of image sensor chips 1a, 1c, and the second row, that is, the second type of image sensor chips 1b, 1d, are the same direction as shown by the arrow X. For example, there is no need for a processing circuit for reversing the reading scanning direction of the image sensor chips 1b, 1d, . . ., which was required in FIG.

The present invention is not limited to the above embodiments; for example, as an image sensor chip, a CCD
In addition to the image sensor, a MOS image sensor or the like can also be used. Further, the first type and the second type of image sensor chips do not necessarily have to have a completely mirror-symmetrical structure; in short, it is sufficient that the transfer directions of the charge transfer sections are opposite to each other.

[Brief explanation of drawings]

Figure 1 shows a conventional staggered array image sensor, Figure 2 shows an example of a CCD image sensor, and Figure 3 shows a staggered arrangement using the CCD image sensor shown in Figure 2 as one image sensor chip. Figures 4a and 4b show an image sensor arranged in the form of a
5 is a diagram showing an example of the structure of a first type and a second type of image sensor chip used in the present invention, and FIG. 5 is a diagram showing an image sensor according to an embodiment of the present invention. 1a, 1b...image sensor chip, 2a,
2b...Photoelectric conversion element array, 11...Chip substrate, 12...Photoelectric conversion element array, 13...Charge storage section, 14...Gate, 15...Charge transfer section,
16... Output section, A, B... Charge transfer direction.

Claims (1)

[Scope of Claims] 1. A photoelectric conversion element array arranged in a row on one side on a substrate, and a charge transfer section that serially transfers and outputs the charge of the photoelectric conversion element array, and Type 1 and type 2 image sensor chips, whose transfer parts have different transfer directions, are arranged in a staggered manner so that the photoelectric conversion element arrays face inward and are located on two parallel straight lines. An image sensor characterized by: 2. The image sensor according to claim 1, wherein the first type and second type of image sensor have mirror-image symmetrical structures with respect to each other.