JP2558471B2 - 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 machine, and substantially arranges a photoelectric conversion element array corresponding to a document in a dimension of 1: 1. The present invention relates to a reading device such as a contact image sensor.

[Prior art and its problems]

Recently, the development of a contact image sensor has become active, and a type of sensor that detects the reflected light from the original through a converging rod lens array as this sensor, or an excellent light transmission rate without using this array In addition, models that have achieved miniaturization have been developed.

FIG. 3 is a schematic diagram showing a coherent reading system that does not use a converging rod lens array, and the light detecting portion 2 corresponding to the original 1 in size is substantially 1: 1. In close contact, the light emitting diode 3 projects the document 1 and the reflected light is received by the photodetector 2.

FIG. 4 shows a reading device comprising a light emitting diode 3 and a light detecting section 2 which the applicant of the present invention has already stabilized.

That is, the common electrode 5 is formed by vapor-depositing Cr, Al, etc. on the light projecting substrate 4 made of glass or the like, and the photoelectric conversion unit 6 made of amorphous silicon or the like is formed on the common electrode 5. A transparent electrode 7 made of a transparent material such as ITO is formed on each photoelectric conversion section 6 by sputtering or vapor deposition. Further, the extraction electrodes 8 are individually connected by vapor-depositing Cr, Al, etc. so as to cover a part of the transparent electrode 7, and a transparent protective layer 9 made of glass or the like is formed on the uppermost portion, and Light transmission light 10 is formed on the common electrode 5, the photoelectric conversion unit 6, and the transparent electrode 7. The light emitting diode 3 is arranged behind the substrate 4, the original 1 is arranged above the protective layer 9, and the light emitting diode 3 irradiates the original 1 through the light transmitting hole 10 and the protective layer 9. The reflected light passes through the transparent electrode 7 near the light transmission hole 10 and is received by the photoelectric conversion unit 6.
Further, an integrated circuit chip 11 composed of a read drive circuit is mounted on the substrate 4, and a contacting underground layer 12 made of Cr or the like and Al or the like on the extraction electrode 8 formed as an individual electrode. The underlayer 13 for a pad made of is sequentially formed, and is wire-bonded to the chip 11 via the lead wire 14a made of the underlayer 13Au for a pad.
Further, the chip 11 is also wire-bonded to the drive signal input electrode 15 via the lead wire 14b. The chip 11 is covered with a shielding cover 16, which allows the original 1 to be smoothly and stably fed to the reading device.

Thus, the signal introduced through the driving signal input electrode 15 sequentially operates the photoelectric conversion element array through the chip 11. Then, in the photoelectric conversion unit 6, electric charges are accumulated according to the amount of incident light, and an output signal is obtained from each element according to the amount of electric charges.

However, when a reading device having such a configuration is mounted on a facsimile device or the like, noise is induced in the common electrode 5 by a noise generation source (for example, a switching power supply, a pulse motor, etc.) of the facsimile device itself,
This adds noise to the read signal, resulting in poor S / N ratio.

The light emitting diode 3 used in the reading device has a structure as shown in FIG.

That is, a plurality of LED chips 18 are arranged in a line on the LED mounting board 17 at a predetermined interval, and a cylindrical rod lens 19 is installed on the LED chip array by a lens supporting member 20. To be done. This rod lens 19 is an LED
Since the irradiation light of the chip 18 can be condensed, the illuminance on the original 1 can be remarkably increased when the original 1 is positioned near its focal length.

However, in this reading device, the distance between the original 1 and the rod-shaped lens 19 is the focal length of the rod-shaped lens 19 (usually about
6 mm), and the height of the light emitting diode 3 is about 10 mm, which makes it necessary to make the thickness of the entire reader at least about 16 mm.
As a result, it is difficult to make the reader even smaller.

[Object of the Invention]

Therefore, an object of the present invention is to provide a high-performance and highly-reliable reading device which shields the photoelectric conversion element array from external noise and has a high S / N ratio.

Another object of the present invention is to provide a reader which achieves miniaturization.

[Means for solving problems]

According to the present invention, a photoelectric conversion element array is formed on one main surface of an insulating substrate, and a long light source in which a plurality of LED chips are arranged is arranged on the other main surface side. Directly projects the object to be detected, which is arranged on the one main surface side, the photoelectric conversion element array receives the reflected light, and the photoelectric conversion element array sequentially obtains a read signal in a time series and further external noise. There is provided a reading device in which at least the longitudinal outer peripheral surface of the elongated light source is covered with a grounded conductor in order to block noise induced from a generation source into the photoelectric conversion element array.

〔Example〕

The present invention will be described below with reference to the embodiments shown in FIGS. 1 and 2.

FIG. 1 is a sectional view of the reading device of the present invention in the sub-scanning direction, and FIG. 2 is an exploded view showing the positional relationship between the insulating substrate and the conductor. In FIGS. 1 and 2 and FIG. 4, the same parts are designated by the same reference numerals.

In the reading apparatus of the present invention, the substrate 4 is attached to the conductor, that is, the substrate supporting member 21, the substrate supporting member 21 is formed with an elongated concave portion 21a in the main scanning direction, and the concave portion 21a is elongated. The light source 22 is arranged. The elongated light source 22 is composed of an elongated insulating recessed body 23 and a plurality of LED chips 24 arranged on the bottom surface of the recessed body 23, and the light emitted from the LED chips 24 is protected by the light transmitting hole 10 and the protection. The original 1 is irradiated through the layer 9, and the reflected light is received by the photoelectric conversion unit 6.

In the reading device having such a configuration, the light source 22 is arranged on the plate surface of the substrate 4 and the rod-shaped lens 19 is not required, and therefore the size can be further reduced. Therefore, when the present inventors prototyped various reading devices,
The distance between the chip 24 and the manuscript 1 can be set to about 6 mm, and even if the thickness of the substrate supporting member 21 is taken into consideration, the thickness of the entire reader can be set to about 10 mm or less.

Further, the light source 22 is formed by an insulating concave body 23, and the light source 22 is close to the photoelectric conversion element array, particularly the common electrode 5, so that a stress is generated between the common electrode 5 and an external noise source. Although the capacitor is easily induced, in the reader of the present invention, the outer circumferential surface of the light source 22 in the longitudinal direction is protected by a conductor and the conductor is grounded. Member 21
And a stray capacitor generated between the external noise generation source and the stray capacitor generated between the photoelectric conversion element array and the external noise generation source become extremely large, and as a result, most of the noise is inductively absorbed by the substrate support member 21. Then, no noise is added to the common electrode 5.

Thus, in the reading device of the present invention, the light source was arranged on the substrate to miniaturize the device itself, and the light source was protected by the conductor, and the conductor could shield the photoelectric conversion element array from external noise.

In the above embodiment, the light source 22 is placed on the plate surface of the substrate 4.
When arranging, a light-shielding film is formed between the both 4 and 22, and a slit or the like is formed in this film, whereby the light quantity transmissivity with respect to the original 1 can be increased.

Furthermore, in the above-mentioned embodiment, the light source 22 is formed by the insulating recessed body 23, and the conductor according to the present invention is explained by the substrate supporting member 21, but as another embodiment, the light source itself is made of a long conductive material. It is also possible to form a concave body and use this as the conductor according to the present invention.

[Advantages of the Invention] As described above, according to the reader of the present invention, the rod-shaped lens (condensing lens), which is required in the LED array, is not required, and thereby the size and cost can be reduced.

Further, according to the reading device of the present invention, noise is not induced in the photoelectric conversion element array by an external noise generation source, so that noise is not added to the read signal,
As a result, a high performance and reliable reader is provided.

The reading device of the present invention is not limited to the above embodiment, and various modifications and improvements can be made without departing from the scope of the present invention.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of the reading device described in the embodiment of the present invention, FIG. 2 is a schematic exploded view showing the dimensional relationship between an insulating substrate and a conductor, and FIG. 3 is a schematic showing a contact type reading system. FIG. 4 is a sectional view of a conventional reader, and FIG. 5 is a schematic view of a light emitting diode. 1 ... Original, 3 ... Light emitting diode 4 ... Substrate, 5 ... Common electrode 6 ... Photoelectric conversion part, 21 ... Substrate support member 22 ... Long light source, 23 ... Long insulating recess body

Claims (1)

(57) [Claims] 1. A photoelectric conversion element array is formed by arranging a plurality of photoelectric conversion elements formed by sequentially forming a common electrode, a photoelectric conversion portion, and a transparent electrode on one main surface of an insulating substrate, and forming individual photoelectric conversion elements. A light passage hole is provided in the conversion element, and a long light source in which a plurality of LED chips are arranged is arranged on the other main surface side, and this long light source is arranged on one main surface side through the above-mentioned light passage hole. A reading device that projects a detected object, receives the reflected light by a photoelectric conversion element array, and sequentially obtains read signals from the photoelectric conversion element array in time series. A reading device characterized in that a conductor is arranged on the other main surface side of the substrate and the conductor is grounded so as to block noise induced from an external noise source to the common electrode.