JPH0728367B2 - 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]

Recently, the development of contact image sensors has become active,
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. 2 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 corresponding to the original 1 in size is substantially 1: 1 in 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.

3 and 4 show a reading device corresponding to the light detecting section 2, and FIG. 4 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, the document 1 is arranged above the protective layer 10, and the light emitted from the light emitting diode 3 is emitted from the substrate 4, the light passage hole 11 and The original 1 is irradiated through the protective layer 10, and the reflected light is transmitted through the light passage hole 11
The light passes through the transparent electrode 8 in the vicinity and is received by the photoelectric conversion unit 7. 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. 5 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.

Still another object of the present invention is to provide a reading device which does not reduce the light quantity transmissivity to the object to be detected even if the condenser lens of the LED light source is unnecessary.

[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. And a photoelectric conversion element array receives the reflected light from the object to be detected on the first plate surface side, and a reading signal is sequentially obtained from the element array in time series. The light source supporting member having an elongated concave portion is provided on the second plate surface side of the substrate, the light source is arranged in the concave portion, and the irradiation light of the light source is reflected on the inner surface of the concave portion. There is provided a reading device characterized in that a reflecting means is formed so that light can be projected onto an object to be detected.

〔Example〕

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

1 is a reading device corresponding to the photodetector shown in FIG. 2, and is a cross-sectional view taken along the section line XX of FIG. 3 in place of FIG. The same parts as those in FIG. 4 in FIG. 1 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 8 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 silver tape 18a having a remarkably large reflectance is attached to the inner side wall of the recess 18, and the recess 18
Is formed by the plate surface of a printed circuit board 20 (a wiring pattern for driving the LED chip 19 is formed on this board 20) attached to the board support 17 on the board surface.
A highly reflective metal thin film 18b made of Al, Cu, Au or the like is formed. Reference numeral 21 is a heat-dissipating metal plate for releasing heat generated when 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. 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.

Further, according to this reading device, since the silver tape 18a and the metal thin film 18b having high reflectance are formed on the entire inner peripheral surface and the bottom surface of the recess 18, the irradiation light of the LED chip 19 is hardly absorbed by the recess 18, and As a result, it is possible to project the original 1 without waste. The reflectances of the silver tape 18a and the metal thin film 18b with respect to the projected wavelength of 570 mm of the LED chip 19 were 80% or more and about 90%, respectively.

Further, in the present embodiment, in forming Cr, Al, etc. on the light projecting substrate 4 to form the common electrodes 6a, 6b ...
A non-evaporated portion is formed in a part of the common electrodes 6a and 6b, and this is formed as a light passage hole 11. Therefore, this common electrode serves as a passage for the light passage hole 11, and the light projected on the vapor deposition metal layer other than this passage is reflected and returns to the concave portion 18 again.
This return light is reflected by the reflection means in the concave portion 18, whereby the light quantity transmissivity with respect to the document 1 is significantly increased.

According to the present invention, it is desirable that the reflectance of the reflecting means in forming the reflecting means is equal to or more than a predetermined value. That is, as a result of repeated experiments by the present inventors, a light source that is normally used (wavelength is within the range of 550 to 660 nm)
If so, it is desirable that the reflectance is 60% or more. If the reflectance is within this range, a practical read signal strength can be obtained.
The preferred reflectance is 80% or more. As a reflection means having such a high reflectance, for example, when the substrate support 17 is made of a metal frame made of Fe or Al, the inner surface of the recess is buffed, a surface grinder, sandpaper,
It may be polished by a method known per se such as electrolytic polishing, or its inner surface may be plated. Also, forming a vapor-deposited metal layer made of Al, Ag, Au, Cu, Rh, etc. on the inner surface of the recess, sticking white paper or cloth, or manufacturing the substrate support 17 itself with white plastics. The inner surface of the recess may be made the plastic white surface.

〔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 not necessary, and even if this lens is not used, the light quantity transmissivity to the object to be detected does not decrease. In addition, miniaturization and cost reduction are achieved, and the signal-to-noise ratio of the read signal strength is improved to obtain excellent resolution.

The present invention is not limited to the above embodiment,
Various reflecting means can be used without departing from the scope of the present invention.

[Brief description of drawings]

1 is a sectional view showing a reading device of the present invention, FIG. 2 is a schematic view showing a reading system relating to the reading device, FIG. 3 is a perspective view of a conventional reading device, and FIG. 4 is a cut in FIG. FIG. 5 is a schematic view showing a light emitting diode used in a conventional reading device, and FIG. 5 is a sectional view taken along the line XX. 1 ... manuscript, 2 ... light detection part 3 ... light emitting diode 5, 17 ... substrate support 14, 19 ... LED chip 15 ... rod lens, 18 ... recess 18a ... silver tape, 18b ... Metal thin film

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 light source support member having an elongated concave portion is provided, and the light source is arranged in the concave portion, and the irradiation light of the light source is reflected on the inner surface of the concave portion, and the reflected light can project the object to be detected. A reading device characterized in that the reflecting means is formed.