JPS61248656A - Contact type optical image detector - Google Patents

Abstract

PURPOSE:To shorten the length of a rod lens and to simplify overall optical system by so constituting the titled device that a light source is located in the direction in which the shade surface of a photodetector is and the light from the source is condensed by the rod lens in order to illuminate an original, so that the reflecting light from the original passed through the rod lens and is condensed again, and is made incident to a photosensor. CONSTITUTION:The photosensors 2 of small area of such as 100mum<3> whose surface of the side facing the light source is shaded by a shading film 1 are arrayed streight perpendicularly to the surface of a paper to form a photodetector part, with constant intervals, for instance, of 150mum on a transparent base plate 3 made of such as glass. Above the said part, the light source 5 made of such as LED array is disposed so that it directly irradiates the shading film 1. And under the same part, the rod lens 4 of 2-3mm-length is disposed in a manner that the light from the source 5 passes through a glass plate 6 that if of the same thickness (aproximately 0.5mm) and refractive index as those of the transparent base plate 3 provided under the rod lens, and condenses the reflecting light from the original on the photosensor.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a close-contact optical image detection device that can be brought into close contact with a document and read the document as an electrical signal.

2. Description of the Related Art In recent years, with the advancement of information technology, close-contact optical image detection devices that can be placed in close contact with a document and read the document as an electrical signal have become important.

Hereinafter, the conventional contact type optical image detection device as described above will be explained with reference to the drawings.

As shown in FIG. 4, the conventional contact type optical image detection device has the following features:
A plurality of optical sensors 22 are arranged on a substrate 21 in a straight line in a direction perpendicular to the plane of the paper. Light source 23 by LED array
The original 24 is illuminated, and the information on the original 24 is focused on the optical sensor 22 through a rod lens.

Problems to be Solved by the Invention However, in the above configuration, in order for the light source 23 to illuminate the document 24 from diagonally above the rod lens 25,
The efficiency of the light source is poor. Ushi, board 21 and manuscript 24
The light source 23 is installed between the two and the light is irradiated from diagonally above, so in order to effectively use the light, the length of the rod lens is about 2 brocades, for example, and the loss of light due to the rod lens is large. Ru. Furthermore, the optical system is complicated because the optical axis of the light source 23 and the optical axis of the rod lens do not coincide.

In view of the above problems, the present invention has a high light utilization efficiency of a light source,
It is an object of the present invention to provide a contact type optical image detection device with a simple optical system.

Means for Solving the Problems In order to solve the above problems, the contact type optical image detection device of the present invention includes a light receiving device in which a plurality of optical sensors, one side of which is shielded from light, are arranged in a row on a transparent substrate. , a light source and a loft lens, the light source is located in the direction of the light-blocking surface of the light receiving device, the light from the light source is focused by the mouth lens and illuminates the document, and the light reflected by the document is reflected again. The light is condensed through a loft lens and enters the optical sensor.

Effect: With this configuration, light from a light source passes through a transparent substrate between a plurality of optical sensors having a light-blocking surface, and is efficiently transmitted by the rod lens to the document surface held at a predetermined distance from the rod lens. The light is focused. Further, the reflected light from the document is again focused on the light receiving surface of the optical sensor by the mouth lens and converted into an electrical signal.

Further, as described above, the light source and the rod lens face each other with the transparent substrate in between, and the length of the rod lens does not depend on the size of the light source. Furthermore, since the light from the light source is effectively focused on the document by the rod lens, the length of the rod lens can be shortened to 2 to 3 m/m.

EXAMPLE A first example of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the contact type optical image detection device according to the first embodiment of the present invention is a light sensor 2 having a small area of, for example, about 10 o/1 m2, which is shielded from light by a surface light shielding film 1 on the light source side. However, on a transparent substrate 3 made of glass, for example,
For example, they are arranged in a straight line in a direction perpendicular to the plane of the paper at regular intervals of about 15,071 m to form light receiving sections. A light source 5 made of, for example, an LED array is arranged above the light receiving part so as to directly irradiate the light shielding film 1, and a rod lens 4 with a length of 2 to 3 m2 is placed below the light receiving part. The light from the rod lens 4 is focused onto the original 7 through the glass plate 6 which has the same thickness (approximately 0.6 m/m) and the same refractive tangent as the transparent substrate 3 provided below the rod lens 4. In addition, it is arranged so that the reflected light from the original document 7 is focused onto the optical sensor 2 .

The structure of the optical sensor 1 used here is shown in FIG.
For example, indium tin oxide (IT
Lower electrodes made of a transparent conductive film using O) are deposited, and then P-type 413, I-type 412, and N-type 411 amorphous silicon layers are sequentially laminated.

On top of that, it also serves as a light-shielding film, such as Cr.
'Each element is constructed by depositing an upper electrode 43 made of metal or the like, and the elements are insulated by forming a transparent inter-element insulating film 44 made of silicon oxide, for example, and further on the upper electrode 43, An An wiring 46 for signal extraction is attached.

The operation of the contact type optical image detection device configured as described above will be explained below.

As shown in FIG. 1, the light from the light source 5 passes through the rod lens 4.
The light is efficiently focused on the 7th surface of the document.

Note that since the optical sensor 2 is provided with the shading film 1, the light from the light source does not directly hit the optical sensor 2.

On the other hand, the image of the original 7 is formed by the rod lens 4 on the light receiving surface of the optical sensor 2, and the optical sensor 2 performs photoelectric conversion to obtain an output signal.

67.7 By making the direction of the projected light from the light source 5 coincide with the optical axis of the loft lens 4, and by making the thickness of the transparent substrate 3 and the glass plate 6 coincide with the focal length of the rod lens 6, the light source The light from 6 is sent to the original 7, and the light reflected from the original is sent to the optical sensor 2.
The light is focused on the light-receiving surface of the

In addition, if high integration technology of semiconductor process is applied, a large number of fine optical sensors (for example, 8/1) can be placed on the transparent substrate 3.
(2) can be formed simultaneously and easily.

In the first embodiment, the optical sensor 2 was fixed to the light source side of the transparent substrate 3, but in the second embodiment, for example, the third
As shown in the figure, the optical sensor 2 may be fixed onto the light shielding film 1 on the rod lens 4 side of the transparent substrate 3. In this case, the rod lens 4 needs to be held such that the distances between its upper and lower end surfaces and the light-receiving surface of the optical sensor and the document correspond to the focal length of the rod lens 4, respectively.

In the first embodiment, the optical sensor is an amorphous silicon optical sensor, but the optical sensor is not limited to an amorphous silicon optical sensor.
Any material may be used as long as it has a photoelectric conversion function. For example, PN junction diodes made of single-crystal silicon may be bonded onto the transparent substrate 3 at predetermined intervals.

Effects of the Invention As described above, according to the present invention, the light from the light source is efficiently focused on the document surface by the rod lens, so that the power of the light source can be small. The optical system is extremely simple, as the light source, optical sensor, and rod lens are aligned in a straight line and the optical axes are aligned. The practical effects of this are impressive.

The light source and rod lens are on opposite sides of the transparent substrate, and the length of the rod lens does not depend on the size of the light source, and the light from the light source is effectively focused on the document by the rod lens. Because light is emitted, the length of the rod lens can be made as short as 1 compared to conventional models.

[Brief explanation of drawings]

FIG. 4 is a sectional view of a contact type optical image detection device according to a second embodiment of the invention, and FIG. 4 is a sectional view of a conventional contact type optical image detection device. 1... Light-shielding film, 22, 2... Optical sensor, 21... Substrate, 3... Transparent substrate, 26,
4... Rod lens, 23, 5... Light source,
6...Glass plate, 24.7...Manuscript, 41
...PIN type amorphous silicon, 411...
...N-type amorphous silicon layer, 412...
Type 1 amorphous silicon layer, 413...P type amorphous silicon! , 42...lower electrode,
43... Upper electrode, 44... Insulating film between light receiving elements, 45... Afi wiring. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 3
Figure 4

Claims (1)

[Claims] A light-receiving section is formed by arranging a plurality of optical sensors each having a light-shielding film on a transparent substrate at a predetermined interval, a light source is provided on the light-shielding film side of the optical sensor, and a rod lens is provided on the light-receiving side of the optical sensor. type optical image detection device.