JPH0519352B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an image reading device with a simple structure and high resolution.

[Technical background of the invention]

2. Description of the Related Art Image reading devices in facsimile machines and office automation equipment conventionally generally perform image reading by focusing an original image on a linear image sensor surface via a spherical lens optical system. However, when using such an optical system,
For example, when scanning and reading an image of an A4-sized document (approximately 210 mm), the optical system requires a distance of approximately 30 cm, leading to an increase in the diameter of the device. In addition, when realizing such an optical system, it is necessary to align the optical axes of the original, the lens, and the linear image sensor, and a skilled technique is required for assembly and maintenance.

Therefore, in recent years, contact type linear image sensors illustrated in FIGS. 1 and 2 have been proposed to compensate for these drawbacks. This close-contact linear image sensor uses a rod lens array in its optical system to form an image of a document with the same size on the optical sensor array surface to read the image. The aim is to miniaturize the device by taking advantage of the short imaging distance of the array, that is, the distance between object images of 15 to 20 mm. That is, in FIG. 1, an image of a document 2 illuminated by a light source 1 such as a fluorescent lamp is transmitted through a rod lens array 3 to a CdSe or CdSe formed on a substrate 4.
The image is input to a photosensor section 5 made of a photoconductive thin film such as CdS. The signal output from the optical sensor section 5 is taken out through matrix wiring to reduce the number of wiring lines, and is called a photoconductive matrix type.

On the other hand, the one shown in FIG. 2 has an optical sensor section 6 on a substrate 4 that uses a diode photovoltaic force such as amorphous Si, a pin junction, or a Schottky barrier.
The IC chip 7 of the signal processing circuit is disposed on the same substrate 4, and is called a charge accumulation mode hybrid type.

[Problems with background technology]

However, the above-mentioned photoconductive matrix type has a simple element structure and excellent photoconductive properties.
Although it has the advantage of high productivity, it has a problem that the response to light irradiation is long, ranging from several milliseconds to several tens of milliseconds, and cannot sufficiently handle high-speed reading. Moreover, since an extra board area is required to realize the matrix wiring structure, a large amount of space is still required for incorporating the device.

In addition, the charge accumulation mode hybrid type has high responsiveness to light irradiation and is suitable for high-speed image reading, but in order to reduce the adverse effects of stray capacitance depending on the wiring formed on the substrate 4, peripheral circuits ( It is necessary to provide the IC 7) close to the optical sensor section 6. For this reason, the peripheral circuitry becomes complicated, the configuration becomes complicated, the cost increases, and productivity is poor. Furthermore, the response of the optical sensor section 6 itself is 1 m.
Although it is possible to read sec/line, the actual operating speed limit is 5 msec/line due to the amount of floating containers mentioned above. Furthermore, there are other problems, such as the need for extra space on the board 4 for incorporating peripheral circuits.

Therefore, attempts have been made to shorten the wiring length or improve the peripheral circuitry, but these efforts are impractical and cause problems such as a decrease in the photodetection output and a deterioration of the S/N ratio. Ta.

[Purpose of the invention]

The present invention was made in consideration of these circumstances, and its purpose is to provide high resolution and
Moreover, it is an object of the present invention to provide a highly practical image reading device equipped with a simple contact type linear image sensor that can operate at high speed and has good mass productivity.

[Summary of the invention]

The present invention provides multiple CCD linear arrays on a long substrate.
The image sensor chips are arranged with their sensor lengths aligned in a straight line, and these CCD
A rod lens array provided on the substrate facing the sensor surface of the linear image sensor chip allows the CCD linear image
This image reading device is characterized in that a contact type image sensor having a sealed sensor chip is arranged opposite to an image surface of an original illuminated by a light source.

In particular, the focal positions of the plurality of contact image sensors are set in a straight line on the original screen, and the position of each CCD linear image sensor chip of the plurality of contact image sensors is set opposite to the original screen. The CCD linear image sensor chips are shifted from each other so that they face each other in a straight line on the original screen.

〔Effect of the invention〕

Therefore, according to the present invention, since the contact type image sensor has a structure in which the rod lens array and the CCD chip are integrated and the CCD chip is sealed, handling thereof is very easy. Furthermore, the simple drive of the CCD chip enables signal extraction without the need for complex processing using conventional peripheral circuitry or routing of wiring, simplifying the structure and downsizing of contact-type image sensors. can be achieved. Moreover, it has tremendous effects such as enabling high-speed and high-resolution image reading.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 3 is a perspective view showing the main parts of the embodiment apparatus, and FIG. 4 is a diagram schematically showing its arrangement structure. The original screen 2 is illuminated by a light source 1 such as a fluorescent lamp, and its image is captured by two contact linear image sensors 11a and 11 arranged opposite to the original screen 2.
b. Close-contact linear image sensor 11 (11a, 11b)
As shown in FIG. 5, a plurality of CCD linear image sensor chips 13 (13a, 13b to 13n) are arranged on a long substrate 12 with the longitudinal direction of the sensor surface 14 aligned in a straight line. established,
A rod lens array 15 is provided on the substrate 12 with a spacer 16 in between, facing the sensor surface 14, and a rod lens array 15 is provided on the substrate 12 with a spacer 16 interposed therebetween.
It has a structure in which the CCD chip 13 is sealed with a lens array 15.

CCD linear image sensor chip 13
The device is operated by receiving a driving power source and a driving pulse through a conductive signal line 17 printed on a substrate 12, and outputs the received light output in time series. The substrate 12 on which such a CCD linear image sensor chip 13 is disposed is provided with a hole 16a at a position facing the chip 13, as shown in the assembled structure in FIG. A spacer 16 which has been subjected to anti-reflection treatment is aligned and tightly fixed, and the rod lens array 15 is further aligned and tightly fixed on this spacer 16. The above anti-reflection treatment blocks input of external light and stray light.
The distance between the rod lens array 15 and the CCD chip 13 is regulated by the spacer 16, and the focal position of one of the rod lenses is regulated by the spacer 16.
It is designed to be set on the sensor surface 14 of No. 3. As a result, a light image introduced through the rod lens array 15 is formed on the sensor surface 14 of the CCD chip 13. In addition, in FIG. 6, the substrate 12, spacer 16, rod lens array 1
The holes shown at 5 are guide holes for these alignments. These are aligned using these guide holes, fixed to each other with adhesive, and the CCD is installed inside.
A linear image sensor chip 13 is sealed and integrated. In this case, the substrate 12,
Rod lens array 15 and spacer 1
It is desirable to make the lengths of the short sides of 6 equal to each other to facilitate alignment and assembly.

Now, the contact type linear image sensors 11a and 11b having such an integrated structure are capable of detecting the original screen 2 illuminated by the light source 1 as described above.
placed opposite. At this time, each sensor 11
a and 11b are provided on a straight line of the original screen 2 with the focal position of the rod lens array 15 aligned. As a result, the original image on a straight line on the original screen 2 is focused on the sensor surface 14 of the CCD chip 13 of each sensor 11a, 11b via the rod lens array 15, and the image is read. Now, the respective CCD chips 13 in these two contact type linear image sensors 11a and 11b are arranged at intervals equal to or less than the effective length l of the sensor surface 14, and for the original screen 2, as shown in FIG. As shown in FIG. 2, the opposing positions are shifted from each other so that the areas where the sensor surfaces 14 are interrupted are mutually compensated for. In other words, any position on a straight line of the original screen 2 is always opposed to the sensor surface 14 of the CCD chip 13 of either one of the sensors 11a, 11b. By arranging the CCD chips 13 in a so-called zigzag pattern, the entire image on a straight line of the original screen 2 can be completely read.

According to the image reading device configured using the contact type linear image sensors 11a and 11b configured as described above, since the sensors 11a and 11b themselves are compact, they can be easily incorporated into the device. The overall size can be made more compact. Moreover, the image sensors 11a and 11b
Since it has an integrated structure, there is no need for complicated alignment of the optical system, it can be easily assembled, and its maintenance is also simple. Moreover, the operating characteristics of the CCD chip 13 and the characteristics of the rod lens combine to enable high-speed operation of, for example, 1 msec/line, and high-resolution image reading of 16 lines/mm.

Specifically, a 2048-pixel CCD linear image sensor (manufactured by Toshiba: TCD102C-1) is mounted on a chip board 12, and a rod lens (manufactured by Nippon Sheet Glass: SLA-20) is bonded to create an integrated structure. When the type linear image sensors 11a and 11b were manufactured and a device was assembled using them, the result was 8 line pairs/mm depending on the resolution of the rod lens.
It was possible to read an image signal with a resolution of .
Furthermore, when three color filters of red, green, and blue were sequentially arranged on the CCD chip at a pitch of 14 μm, it was confirmed that image signals with good color separation could be obtained.

As explained above, according to the present invention, the conventional
It is possible to easily downsize the device, which has been a problem with image reading devices structured using a CCD linear image sensor and a spherical lens system. Moreover, the sensor structure shown in Figs. 1 and 2, which was conventionally considered, cannot be expected at all.
Enables high-resolution image reading through high-speed operation. Also, a rod lens 15 and a spacer 16
functions as a package body for the CCD chip 13, which simplifies the production process and improves image quality.
The sensor itself can be made smaller. Furthermore, the substrate 1
2 is easy to manufacture, and there is no need to form peripheral circuits, so it has the advantage of increasing mass productivity. Furthermore, it is possible to significantly reduce manufacturing costs.

Note that the present invention is not limited to the above embodiments. For example, whether or not to provide a color filter on the CCD chip surface can be determined depending on the specifications. Furthermore, two sets of CCD chips arranged in a staggered manner facing the document screen may overlap each other at their ends to read images, thereby making the connection between the images smooth. . Furthermore, the number of CCD chips sealed to one contact type linear image sensor may be determined as appropriate. Of course, it is also possible to use an LED array or the like as a light source. In short, the present invention can be implemented with various modifications without departing from the gist thereof.

[Brief explanation of the drawing]

Figures 1 and 2 are schematic configuration diagrams of conventional contact type linear image sensors, respectively;
FIG. 3 is a perspective view showing the main parts of a device according to an embodiment of the present invention, FIG. 4 is a diagram showing the arrangement structure in the same embodiment, and FIG. 5 is a plan view of a contact type linear image sensor according to the present invention. FIG. 6 is a diagram showing the assembly structure of the linear image sensor, and FIG. 7 is a diagram showing the arrangement of CCD chips. 1... Light source, 2... Original screen, 11a, 11b
...Contact linear image sensor, 12...
Substrate, 13... CCD linear image sensor chip, 14... Sensor surface, 15... Rod lens array, 16... Spacer.

Claims (1)

[Claims] 1. A substrate, a plurality of CCD linear image sensor chips arranged on the substrate with the longitudinal direction of the sensor surface aligned in a straight line, and these plurality of CCD linear image sensor chips.
A rod lens array is provided to face the sensor surface of the CCD linear image sensor chip, and a spacer is provided between the substrate and the rod lens array. A close-contact image sensor formed by sealing the plurality of CCD linear image sensor chips with an array, a substrate, and a spacer is arranged opposite to an image surface of an original illuminated by a light source. image reading device.