JPH07203130A - Close contact image sensor - Google Patents

Abstract

PURPOSE:To make the manufacturing process efficient by using one adhering means to fix components of the close contact image sensor mutually. CONSTITUTION:An original platen glass 14 and an optical guide plate 24 are all transparent, through which an ultraviolet ray is transmitted. Thus, a UV curing resin is coated in advance to each adhered face of a frame 12, the original platen glass 14, the optical guide plate 24 and 'selfoc (R)' lens array 32, and the UV curing resin is cured by an ultraviolet ray reaching each adhered face by emitting the ultraviolet ray from the upper side after each component is assembled. Furthermore, similar UV curing resin is used for resin sealing between the light emitting element 22 and the optical guide plate 24 to attain the curing processing altogether.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact type image sensor used as a document reading device in a small facsimile, a copying machine or the like.

[0002]

2. Description of the Related Art FIG. 3 is a schematic sectional view of a conventional contact image sensor. FIG. 3 shows a cross section of the contact image sensor taken along a plane perpendicular to the longitudinal direction (main scanning direction). Such a contact image sensor includes a frame 52, a document surface glass 54, a substrate 56 on which a light emitting element 56a made of an LED is mounted, and a SELFOC lens array 58.
And a substrate 62 on which the photoelectric conversion means 64 is mounted. The frame body 52 holds each component in a fixed relationship. The document surface glass 54 is a frame 52
The original is slid on the original surface glass 54, and the original slides on the original surface glass 54.

A large number of light emitting elements 5 provided on the substrate 56.
6a is for irradiating the original with light, and is provided substantially above the center of the frame 52. Further, for example, in the case of A4 size, 32 light emitting elements 56a are mounted on the substrate 56 along the main scanning direction. The substrate 56 is arranged so as to be inclined at about 45 ° with respect to the document surface glass 54, and the light emitting element 56a is kept at a constant distance from the document reading position. The reason why the light emitting element 56a is kept too close to the original surface glass 54 is that the illuminance at the reading position P of the original becomes poor, and the light emitting element 5a keeps a constant distance.
This is because only just above 6a becomes extremely bright. The light emitting element 56a is potted with a resin 56c in order to improve environment resistance such as humidity resistance and to protect the bonding wire 56b. The resin 56c also has a lens effect and improves the directivity of light.

In the SELFOC lens array 58, the sensor element 64, which is photoelectric conversion means, reflects the light emitted from the light emitting element 56a and reflected by the document at the document reading position P.
Is an optical system for focusing on the frame 52, and is provided on the frame 52 through a spacer 66 at the center of the frame 52. The mounting substrate 62 is provided below the frame body 52, and a large number of sensor elements 64 are mounted on the mounting substrate 62 along the main scanning direction.

To read a document placed on the document surface glass 54, first, the light emitting element 56a is caused to emit light, and the light is applied to the document reading position P. Then, the reflected light reflected by the document at the document reading position P is focused on the sensor element 64 on the mounting substrate 62 by the SELFOC lens array 58. The sensor element 64 reads an image for one line from the reflected light, converts it into an electric signal, and outputs it. Then, as the document slides in the sub-scanning direction, the sensor element 64 reads an image line by line, and the entire image of the document is captured as an electric signal.

[0006]

By the way, since the substrate 56 does not transmit light, the back surface of the substrate 56 and the frame 52 cannot be fixed by the UV curable resin. Therefore, in the conventional contact-type image sensor shown in FIG. 3, the substrate 56 is fixed by a double-sided tape, the SELFOC lens array 58 is made of an adhesive such as a silicone resin, and the original surface glass 54 is made of a UV curable resin (UV rays). Each of them is fixed to the frame body 52 by a cured resin). As described above, in the conventional contact image sensor, a plurality of fixing means must be used in the assembly process, and there is a problem that efficiency is low.

The present invention has been made in view of the above circumstances, and the contact type image sensor in which the efficiency of the assembly process is improved by allowing the constituent members held by the frame to be fixed by one fixing means. It is intended to provide.

[0008]

According to a first aspect of the present invention for solving the above-mentioned problems, an original surface glass on which an original slides and a light emitting means for irradiating the original with light are mounted, and the original surface is the original. A substrate arranged to be in contact with the face glass, a light guide means for guiding the light emitted by the light emitting means to the vicinity of the reading position of the original document, and an optical system for focusing the light from the light emitting means reflected by the original document. A photoelectric conversion means for converting the light focused by the optical system into an electric signal; a glass body for holding the original surface glass, the substrate, the light guide means, the optical system, and the photoelectric conversion means. Then
At least the original surface glass and the substrate, the original surface glass and the light guide means, the original surface glass and the frame body, and the optical system and the frame body are fixed to each other by a UV curable resin. To do.

According to a second aspect of the present invention, in the first aspect of the invention, the space between the light emitting means on the substrate and the light guide means is sealed with the UV curable resin. .

[0010]

According to the invention described in claim 1, the original surface glass, the optical system and the light guide means are transparent by the above construction,
Transmits ultraviolet light. Further, by providing the light guide means capable of guiding the light to the reading position of the original without waste, the degree of freedom of arrangement of the substrate on which the light emitting means is mounted is increased, and the substrate is placed at a position where the ultraviolet light reaching the optical system is not blocked. Can be provided. Therefore, the original surface glass,
When the substrate, the light guide means, and the optical system are assembled inside the frame body, these parts are in contact with each other, in particular, the document surface glass and the substrate, the document surface glass and the light guide means, the document surface glass and the frame body, and UV curing resin is applied to the area where the optical system and the frame are in contact with each other, and then UV rays are radiated to make U
By curing the V-curable resin, it is possible to fix the above-mentioned constituent members to each other and to provide sufficient strength.

According to a second aspect of the present invention, by the above configuration,
By sealing the space between the light emitting means on the substrate and the light guide means with a UV curable resin, the UV curable resin protects the light emitting means. This UV curable resin can be the same as the UV curable resin used for fixing when assembling the original surface glass, the substrate, the light guide means, and the optical system inside the frame body as described above. It can be cured simultaneously with the UV curable resin for fixing each component. The UV curable resin also plays a role of effectively guiding the light from the light emitting means to the light guide means.

[0012]

EXAMPLES Examples will be described below with reference to the drawings. Here, FIG. 1 is a schematic cross-sectional view of a contact image sensor which is an embodiment of the present invention. In addition, in FIG.
The cross section by the plane perpendicular to the longitudinal direction (main scanning direction) of the contact image sensor is shown.

The contact image sensor of this embodiment is shown in FIG.
As shown in FIG. 2, a frame 12, a document surface glass 14, a substrate 20 on which a large number of light emitting elements 22 are mounted in the main scanning direction,
The light guide plate 24 is a light guide unit, the SELFOC lens array 32, and a substrate 34 on which a large number of sensor elements 36, which are photoelectric conversion units, are mounted in the main scanning direction. This contact image sensor is for A4 size and has a length in the main scanning direction of about 230 mm.

The frame 12 holds the respective constituent members in a fixed positional relationship and is obtained by extruding a metal such as aluminum or stainless steel. The document surface glass 14 is provided on the upper portion of the frame body 12, and the document slides on the document surface glass 14. LEDs on the substrate 20
16 light emitting elements 22 are provided. 16
The individual light emitting elements 22 are mounted on the substrate 20 at intervals of about 14 mm in the main scanning direction. The substrate 20 is inserted and fitted into a groove 12a of a frame body 12 formed at an end portion of the lower side of the document surface glass 14 in the sub-scanning direction, and the frame body 12 is perpendicular to the document surface glass 14. Fixed to. With such a configuration, it is possible to effectively prevent the substrate 20 from being warped and deformed during use.

The light guide plate 24 guides the light emitted from the light emitting element 22. One end face of the light guide plate 24 faces the light emitting element 22, and the other end face is arranged near the SELFOC lens 32. The length L of the light guide plate 24 in the sub-scanning direction is about 8 mm. As the material of the light guide plate 24, a transparent resin such as an acrylic resin is used. Acrylic resin is characterized by good workability and very low cost. The light guide plate 24 is processed by molding or cutting, and the light guide plate 24 does not need to be subjected to any special end surface treatment. The light guide plate 24 is transparent and transmits ultraviolet rays for curing the UV curable resin as described later.

The optical coupling resin 26 is used for the light emitting element 22.
The light emitting element 22 so that the coupling loss of light between the light guide plate 24 and the light guide plate 24 is reduced, that is, the light emitted from the light emitting element 22 enters the light guide plate 24 efficiently.
The light guide plate 24 and the light guide plate 24 are sealed. The optical coupling resin 26 is, for example, a transparent U described later.
V-curable resin can be used.

The SELFOC lens array 32 is provided substantially at the center of the frame 12, and the reflected light emitted from the light emitting element 22 and reflected by the document at the document reading position P is focused on the sensor element 36. It is a thing. The SELFOC lens array 32 is configured by bundling a large number of optical fibers. As the SELFOC lens array 32, as shown in FIG. 2A, SLA20D manufactured by Nippon Sheet Glass Co., Ltd. having a width w of 0.6 mm and a focal length (TC (total conjugate) length) d of 9.1 mm is used. The TC length d corresponds to the distance from the document reading position to the sensor element 36.

A mounting board 34 provided under the frame 12
A large number of sensor elements 36 are mounted in the main scanning direction. The sensor element 36 includes a photodiode and a blocking diode. The photodiode is for converting the reflected light from the original, which is focused by the SELFOC lens array 32 and is incident, into an electric signal, and the blocking diode is for switching when the electric charge corresponding to the image information from each photodiode is taken out. Functions as an element.

In the contact image sensor of this embodiment, the light guide plate for guiding light from one end to the other end is provided, and the space between the light emitting element and the light guide plate is sealed with the optical coupling resin, so that the light emitting element is Since the light emitted by the can be efficiently guided to the vicinity of the SELFOC lens array, even if the number of light emitting elements is reduced to about half compared to the conventional one, the same illuminance can be obtained at the document reading position. .

Conventionally, it has been necessary for the light emitting element to be resin-sealed by potting in order to improve the environment resistance and protect the bonding wire. However, in this embodiment, since the space between the light emitting element and the light guide plate is sealed with the optical coupling resin, the optical coupling resin has the functions of improving the environmental resistance and protecting the bonding wires as described above. Therefore, it is not necessary to seal the light emitting element with resin by potting as in the related art.

Further, in the contact type image sensor of this embodiment, the light emitting element is provided at the lower end in the sub-scanning direction on the lower side of the document surface glass so as to be perpendicular to the document surface glass. It is possible to reduce the height of the contact-type image sensor as compared with the conventional one in which the contact-type image sensor is tilted at 45 ° with respect to the original reading position and kept at a constant distance from the original reading position. For example, as a SELFOC lens array, conventionally, as shown in FIG. 2B, the width w is 0.9 m.
SLA2 made by Nippon Sheet Glass with m and TC length of 14.4 mm
Although 0B was used, in this embodiment, the width w is 0.6 m.
SLA20 made by Nippon Sheet Glass with m and TC length of 9.1 mm
By using D, the distance from the document reading position to the sensor element is shortened, and the contact-type image sensor can be made thinner and more compact. In addition, since the selfoc lens array having a shorter TC length is cheaper, the cost can be further reduced.

By the way, in FIG. 1, the document surface glass 1
4 and the frame 12 are joined surfaces 40a and 40b, the original surface glass 14 and the substrate 20 are joined together, the original surface glass 14 and the light guide plate 14 are joined together, and the SELFOC lens array 32 and the frame body are joined together. The joint surface 46 with 12 is fixed by an ultraviolet curable resin. This UV curable resin is characterized in that it can be easily cured by irradiating it with ultraviolet rays.

As described above, the original surface glass 14 and the light guide plate 24 are both transparent and transmit ultraviolet rays. Therefore, when the ultraviolet rays are irradiated from the upper side, the ultraviolet rays reach the above-mentioned bonding surfaces. Therefore, before assembling each constituent member, a UV curable resin is applied to each joint surface in advance using a dispenser or the like, these constituent members are assembled in a predetermined arrangement, and ultraviolet rays are irradiated from the upper side. It is possible to simultaneously cure the respective joint surfaces to fix the respective constituent members to each other. With this configuration, the efficiency of the assembly process can be significantly improved, as compared with the conventional case where different fixing means are used depending on the joint surfaces.

Further, in this embodiment, as the optical coupling resin 26, the same UV curing resin as that used for joining is used. As a result, the optical coupling resin 26 can be simultaneously cured at the same time as the UV curable resin for bonding at the end of the assembly process, and the manufacturing efficiency can be further improved. In the conventional case, the temperature rise due to continuous energization of the light emitting element 22 causes a flux to flow out when the chip resistors on the substrate 20 are soldered, which may cause a problem that the original surface glass becomes cloudy. . However, in this embodiment, by sealing with the coupling resin 26 as shown in FIG.
Generation of such flux can be effectively suppressed.

Next, the operation of the contact image sensor of this embodiment will be described. First, the document is placed on the document surface glass 14 with the document surface facing down. Then, the light emitting element 22
When the light is emitted, the light efficiently enters the light guide plate 24 through the optical coupling resin 26, and is efficiently guided to the vicinity of the SELFOC lens array 32 through the light guide plate 24. A part of the light extracted from the end surface of the light guide plate 24 directly illuminates the document reading position P on the document surface glass 14, and the other part of the light illuminates the frame body 12.
The original reading position P is illuminated by the reflected light.

The reflected light reflected by the document at the document reading position P is focused by the SELFOC lens array 32 on the sensor element 36 on the mounting substrate 34, and the sensor element 36 reads an image for one line from the reflected light. ,
It is converted into an electrical signal and output. Then, as the document slides in the sub-scanning direction, the sensor element 36 reads an image line by line, and the entire image of the document is captured as an electric signal.

The present invention is not limited to the above embodiment, but various modifications can be made within the scope of the gist thereof. For example, in the above embodiment, the document surface glass 14, the light guide plate 24, the substrate 20, and the SELFOC lens array 32 are all fixed with UV curable resin.
If it is difficult to reach the selfoc lens array 32 with ultraviolet rays, the selfoc lens array 32
May be fixed by another means such as a silicone resin adhesive.

[0028]

As described above, according to the first aspect of the invention, the original surface glass, the substrate on which the light emitting means is mounted, the light guide plate, and the optical system are made of the UV curable resin inside the frame. By mutually fixing, the UV curable resin is applied to the joint surfaces in advance, and after assembling each constituent member, the UV curable resin on each joint surface is collectively cured by irradiation with ultraviolet rays. Therefore, it is possible to provide a contact type image sensor in which the efficiency of the assembly process is improved.

According to the second aspect of the invention, the same UV as the joint surface is provided between the light emitting means and the light guide means.
By encapsulating with a curable resin, the UV curable resin can be simultaneously cured at the same time as the UV curable resin used for fixing on the joint surface, and the flux used for soldering the board can flow out. It is possible to provide a contact image sensor that can effectively prevent the above.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a contact image sensor that is an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a Selfoc lens array used in an example.

FIG. 3 is a schematic cross-sectional view of an example of a conventional contact image sensor.

[Explanation of symbols]

 12, 52 Frame 14, 54 Original surface glass 20, 34, 56, 62 Substrate 22, 56a Light emitting element 24 Light guide plate 26 Optical coupling resin 32, 58 SELFOC lens array 36, 64 Sensor element 40a, 40b, 42 , 44, 46 Bonding surface

Claims (2)

[Claims] 1. A manuscript surface glass on which a manuscript slides, a substrate on which a light emitting means for irradiating the manuscript with light is mounted, and a surface of which is placed in contact with the manuscript surface glass, and a light emitted by the light emitting means. Light guide means for guiding the vicinity of the reading position of the original, an optical system for converging the light from the light emitting means reflected by the original, and a photoelectric conversion means for converting the light converged by the optical system into an electric signal. A frame for holding the document surface glass, the substrate, the light guide means, the optical system, and the photoelectric conversion means, and at least the document surface glass and the substrate, the document surface glass and the light guide. A contact type image sensor characterized in that the means, the document surface glass and the frame body, and the optical system and the frame body are fixed to each other by a UV curing resin. 2. The contact type image sensor according to claim 1, wherein a space between the light emitting means on the substrate and the light guide means is sealed with the UV curing resin.