JPH0728366B2 - Reader - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is aimed at, for example, miniaturization of a facsimile apparatus, and a photoelectric conversion element array substantially corresponding to an original in a size of 1: 1 is arranged. The present invention relates to a reading device such as a contact image sensor.

[Prior art and its problems]

The development of approximation and contact type image sensors has been activated,
This sensor has been developed into a type that detects reflected light from a document through a converging rod lens array, and a type that achieves excellent light transmission rate and miniaturization without using this array.

FIG. 4 is a schematic diagram showing a close contact type reading system which does not use a converging rod lens array, in which the light detecting section 2 which is substantially 1: 1 in size with the original 1 comes into close contact with the original 1. Then, the light emitting diode 3 projects the original 1 and the reflected light is received by the photodetector 2.

5 and 6 show a reading device corresponding to the light detecting section 2, and FIG. 6 is a sectional view taken along the section line XX in FIG.

That is, a transparent substrate 4 made of glass or the like is attached to a substrate support 5 made of a metal frame or the like, and Cr, Al, etc. are vapor-deposited on the substrate 4 to form common electrodes 6a, 6b ... Is formed, a photoelectric conversion part 7 made of amorphous silicon or the like is formed on the common electrodes 6a, 6b, and a transparent electrode 8 made of a transparent material such as ITO is formed on the photoelectric conversion part 7 by sputtering or vapor deposition. It is formed in each photoelectric conversion part 7. Further, the extraction electrodes 9 are individually connected by vapor-depositing Cr, Al, etc. so as to cover a part of the transparent electrode 8, and a transparent protective layer made of glass or the like is provided on the uppermost part.
10 is formed, and a light passage hole 11 is formed in the common electrodes 6a and 6b, the photoelectric conversion section 7 and the transparent electrode 8. The light emitting diode 3 is arranged behind the substrate support 5. And
The original 1 is arranged above the protective layer 10, and the light emitted from the light emitting diode 3 is transmitted through the substrate 4, the light passage hole 11 and the protective layer 10.
The original 1 is illuminated via the transparent electrode 8 and the reflected light is transmitted through the transparent electrode 8 near the light passage hole 11 and is received by the photoelectric conversion unit. Further, the light passage holes 11 are arranged at intervals along the width direction (main scanning direction) of the original 1, that is, along the axial direction of the light emitting diode 3, and a drive circuit 12 such as a shift register is mounted on the substrate 4. To be done.

Further, FIG. 7 shows the light emitting diode 3. That is, LE
A plurality of LED chips 14 are arranged in a line on a D mounting substrate 13 with a predetermined interval, and a cylindrical rod lens 15 is located on the LED chip array and the central axis of the cylinder is an LED chip. The lens support member 16 is installed so as to be parallel to the array. Since the rod-shaped lens 15 can collect the irradiation light of the LED chip 14, the illuminance on the original 1 can be remarkably increased when the original 1 is positioned near its focal length.

However, according to this reading device, the distance between the original 1 and the rod-shaped lens 15 is equal to the focal length of the rod-shaped lens 15 (usually about
6 mm), and the height of the light emitting diode 3 is about 10 mm, so that the thickness of the reading device composed of the light detecting section 2 and the light emitting diode 3 is at least about 16 mm. As a result, making it even more difficult to miniaturize the reader.

[Object of the Invention]

Therefore, it is an object of the present invention to provide a reading device which is downsized by not using a condenser lens of an LED light source.

Another object of the present invention is to provide a reading device which achieves cost reduction by eliminating the condenser lens of the LED light source.

[Means for solving problems]

According to the present invention, a photoelectric conversion element array is formed on a first plate surface of a substrate, and a light source is provided on a portion of the substrate corresponding to the element array on the second plate surface side. In the reading device in which the object to be detected is projected, the reflected light is received by the photoelectric conversion element array, and read signals are sequentially obtained from this element array in time series, on the second plate surface side of the substrate. A reading device is provided, which comprises a light source support member having an elongated recess, and the light source is disposed in the recess.

〔Example〕

 Next, an embodiment of the present invention will be described with reference to FIG.

1 is a reader corresponding to the photodetector shown in FIG. 4, but is a cross-sectional view taken from the section line XX of FIG. The same parts as those in FIG. 6 are designated by the same reference numerals.

That is, the translucent substrate 4 is attached to the substrate support 17 composed of a metal frame or the like, and the common electrode 6 is provided on the substrate 4.
The photoelectric conversion part 7, the transparent electrode 8, the extraction electrode 9, and the protective layer 10 are sequentially formed. A long recess 18 is formed in the substrate support 17 substantially in parallel with the light receiving element array, and a plurality of LED chips 19 are provided on the bottom surface of the recess 18 at a predetermined interval (pitch) in the main scanning direction. Are arranged in. A printed circuit board 20 is attached to the substrate support 17, which forms the bottom surface of the recess 18, and a wiring pattern for driving the LED chip 19 is formed on the printed circuit board 20. Further, the printed board 20 is provided with a heat-dissipating metal plate 21 for radiating heat generated as the LED chip 19 is driven.

According to this reading device, the light detecting section 2 shown in FIG.
Further, the light emitting diode 3 is integrated, and according to the experiments by the present inventors, if the distance between the LED chip 19 and the manuscript 1 is set to about 6 mm, the manuscript 1 can be projected with sufficient brightness. Therefore, even if the thicknesses of the printed circuit board 20 and the heat-dissipating metal plate 21 are taken into consideration, the total thickness of the reading device can be set to about 10 mm or less.

In addition, the reading device used in this embodiment is 2 to 16 dots /
When the resolution is set to mm, the size of the recess and LE
It was found from an experiment conducted by the present inventors that the pitch of the D chip should be set within the following range.

That is, the width w of the recess shown in FIG. 1 should be set in the range of 0.5 to 3 mm, preferably 1 to 2 mm.
If it is less than 3 mm, it becomes difficult to mount the LED chip, and if it exceeds 3 mm, the common electrodes 6a, 6b ... Can not be shielded completely and stray light is generated.

Further, as is clear from FIG. 2, the depth d of the concave portion causes a significant difference in illuminance depending on its size. In other words, A in the figure
B and C show the illuminance with respect to the distance from the LED chip when d is set to 2.0 mm, 3.0 mm and 5.0 mm respectively, and when d = 2.0 mm (A), it is the highest near the LED chip installation. Although the illuminance is shown, the illuminance decreases remarkably as the distance from the LED chip increases. On the other hand, d
= 3.0mm (B), and d = 5.0mm (C). As d increases, the illuminance near the LED chip installation decreases, but on the other hand, the illuminance is relatively small even if the LED chip is far away. Has been maintained.

Then, the inventors of the present invention measured the illuminance distribution in the main scanning direction when the pitch P of the LED chips was set to 5 mm and d was set to 3 ways as described above, and the results shown in FIG. 3 were obtained. Was obtained.

In FIG. 3, a, b, and c are d = 2.0 mm, 3.0 mm, and 5.
The illuminance distribution is set to 0 mm, and as is clear from the figure, the illuminance decreases as d increases, but the illuminance distribution is uniform over the main scanning direction.

Therefore, based on the above-mentioned experimental results, the present inventors set the depth d of the recess and the pitch P of the LED chip to 3 to 8 mm and 8 m, respectively.
m or less, preferably depth d is 4-5 mm, pit P is 2-6 mm
I found that it should be set to. If the depth d is less than 3 mm, the variation in the illuminance distribution becomes large and uniform output signal intensity cannot be obtained for each light receiving element. If the depth d exceeds 8 mm, the illuminance becomes small and the output signal intensity of the light receiving element becomes small. Further, when the pitch P of the LED chips exceeds 8 mm, the illuminance distribution of the chip array itself is significantly varied, and uniform output signal intensity cannot be obtained for each light receiving element.

〔The invention's effect〕

As described above, according to the reading device of the present invention, the rod-shaped lens (condensing lens) of the LED array is unnecessary, and
The D chip pitch was maintained at a certain size to reduce the amount of chips used, which resulted in further miniaturization and cost reduction.

Further, when the reader is equipped with an LED array having a rod-shaped lens, it is not possible in the current mass production technology to accurately arrange the LED chip array in a straight line and set all the chips at the focus of the rod-shaped lens. It is possible, and as a result, an even illuminance distribution in the main scanning direction cannot be obtained. On the other hand, according to the reading apparatus of the present invention, since the rod-shaped lens is not used, accurate focusing is not required, so that the manufacturing of the LED chip array is simplified, and thus the reading with high quality and high reliability is achieved. A device is provided.

The present invention is not limited to the above embodiment,
Various changes and improvements may be made without departing from the scope of the present invention.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the reading device of the present invention, FIG. 2 is a diagram showing the relationship between the distance from the LED chip and the illuminance with respect to the depth of the recess shown in this embodiment, and FIG. Diagram showing LED chip and illuminance distribution based on the results shown in Fig. 2,
FIG. 4 is a schematic view showing a reading system of the reading device, FIG.
FIG. 7 is a perspective view of a conventional reader, FIG. 6 is a sectional view taken along section line XX in FIG. 5, and FIG. 7 is a schematic view showing a light emitting diode used in the conventional reader. 1 ... manuscript, 2 ... light detection part 3 ... light emitting diode 5, 17 ... substrate support 14, 19 ... LED chip 15 ... rod lens, 18 ... recess

Claims (1)

[Claims] 1. A photoelectric conversion element array is formed on a first plate surface of a substrate, and a light source is provided on a portion corresponding to the element array on the second plate surface side of the substrate, and the light source is on the first plate surface side. In the reading device in which the photoelectric conversion element array receives the reflected light and the read signals are sequentially obtained in time series from the element array, the long side is extended to the second plate surface side of the substrate. A reading device comprising a light source support member having a scale-shaped recess, wherein the light source is arranged in the recess.