JPH07131585A - Contact-type image sensor - Google Patents

Abstract

PURPOSE:To easily assemble a frame while the dimensional precision and the mechanical rigidity of an optical system are held. CONSTITUTION:A frame consists of a high precision member 10 and a resin member 12. The high precision member pushes and shapes aluminum or press- works and manufactures a steel plate. Thus, the high dimensional precision of original surface glass 24, a light-receiving element 20 and a rod lens 22, which are provided on the high precision member, can be obtained. Parts which are originally worked in a different process after the frame is manufactured such as a light-guiding groove part and a screw hole are integrally worked at the time of injection-molding the resin member. Thus, the frame can easily be assembled by inserting the high precision member into a groove 18 provided for the resin member and fixing it by an engaging member 16.

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 or a copying machine.

[0002]

2. Description of the Related Art FIG. 9 is a perspective view of a conventional contact image sensor as seen from one end. In the figure, a frame (frame) 50 is made of aluminum, which is obtained by extruding a solid aluminum material in the longitudinal direction (main scanning direction). A document surface glass 52 through which a document passes and a light receiving element mounting substrate 54 on which a light receiving element is mounted are provided on the upper portion of the frame 50, and the positional relationship between the two is defined by the vertical dimension of the frame 50. .
At the center of the frame 50, there is an L for illuminating the document.
A lens 58 for focusing the reflected light from the ED light source 56 and the original on the light receiving element is provided.

In the contact type image sensor of FIG. 9, the document slides on the document surface glass 52 in the sub-scanning direction (direction of arrow in the figure) with the document surface facing downward. At this time, the light emitted from the LED light source 56 is reflected on the original surface, and the lens 5
The light is focused on the light receiving element substrate 54 by 8. One line of light receiving elements for photoelectrically converting light is provided in a line on the light receiving element substrate 54, and as the document moves in the sub-scanning direction, the image is read line by line, converted into an electric signal, and output. In this way, the image of the document is captured as an electric signal.

The contact type image sensor has a document surface glass 52, a light receiving element mounting substrate 5 in order to obtain an accurate image signal.
Regarding the positional relationship between the lens 4 and the lens 58, high dimensional accuracy is required. For example, even if there is a positional error of about 0.1 mm between the document surface glass 52, the lens 58, and the light receiving element, the focus may shift or the MTF (Modulation Transfer)
Function) may decrease. For this reason, as the frame 50 of the conventional contact type image sensor, a product obtained by extruding aluminum having high dimensional accuracy and excellent mechanical rigidity is used. That is, once the mold is made to have an accurate size, a frame having a high dimensional accuracy can be easily manufactured by subsequently extruding aluminum using this mold.

[0005]

The frame 50 of the conventional contact type image sensor shown in FIG. 9 is obtained by extruding a solid aluminum material, but screws for attaching to other equipment, for example, a facsimile body. Grooves and holes such as holes (not shown) in the direction perpendicular to the longitudinal direction require processing in a later step in addition to extrusion formation. When the number of steps is increased as described above, there is a problem that manufacturing efficiency is lowered and cost is increased.

[0006] Recently, a frame made of resin has been developed. Resin can be easily injection-molded and can be molded in a batch including grooves and holes in the direction perpendicular to the longitudinal direction, so the frame can be manufactured more efficiently than when aluminum is used as the material. . However, resin is easily twisted or distorted by applying a slight force, and is not suitable as a material for a frame to which a lens or the like that requires high dimensional accuracy is attached.

In order to solve such a drawback, it may be possible to manufacture the frame from a resin containing glass fiber or carbon fiber inside the base material, but the cost is high and the frame of the contact type image sensor is expensive. Not suitable as

The present invention has been made in view of the above circumstances, and an object thereof is to provide a contact type image sensor which can secure sufficient dimensional accuracy, can be manufactured at a low cost and in a simple process. To do.

[0009]

According to a first aspect of the present invention, there is provided a contact type image sensor for solving the above-mentioned problems.
A transparent substrate on which the document is slid, a light source for irradiating the document with light, an optical system for focusing the light from the light source reflected by the document, and a beam passing through the optical system for focusing. In a contact image sensor having a frame body that holds a plurality of photoelectric conversion elements that convert light into an electric signal, the frame body has a reference surface that defines a relative distance between the translucent substrate and the photoelectric conversion element, and It is characterized in that a high precision member having an optical system mounting surface for mounting the optical system and a resin member for holding the light source are assembled.

According to a second aspect of the present invention, in the contact type image sensor, side plate portions having fitting portions are provided at both ends of the resin member, and both ends of the high precision member are fitted in the respective fitting portions. The frame body is assembled according to the above.

A contact image sensor according to a third aspect of the present invention is characterized in that a positioning portion for fixing the optical system at a predetermined position is provided on the high precision member.

According to a fourth aspect of the present invention, in the contact type image sensor, when the resin member and the high precision member are assembled, the pressing member for pressing the optical system to the high precision member side is the resin. It is characterized in that it is provided on a member.

According to a fifth aspect of the present invention, in the contact type image sensor, the high precision member is made of aluminum.

According to a sixth aspect of the present invention, in the contact type image sensor, the high precision member is made of a steel plate.

[0015]

According to the first aspect of the present invention, with the above structure, the positional relationship between the light-transmitting substrate, the light receiving element, and the optical system is regulated by the high-precision member, so that the dimensional accuracy of these positional relationships is sufficiently secured. be able to. Further, since the resin member that constitutes the frame together with the high precision member can be easily manufactured by injection molding, the grooves and holes that need to be provided in the direction orthogonal to the longitudinal direction of the frame are not formed on the resin member during the injection molding. Can be integrally provided on the high precision member, and therefore, a post process for providing such a groove or hole on the high precision member is unnecessary.

According to the second aspect of the present invention, the high-precision member is simply fixed to the resin member by fitting the high-precision member to the fitting portions on the side plate portions provided at both ends of the resin member. Therefore, the assembly of the high precision member and the resin member becomes easy.

According to the third aspect of the present invention, by providing the positioning portion on the high-accuracy member according to the above configuration, the optical system can be easily attached, and the positional error of the attached optical system can be prevented, which results in high optical performance. Accuracy is secured.

According to the fourth aspect of the present invention, since the pressing member is provided on the resin member with the above configuration, the optical system is pressed against the high accuracy member side when the high accuracy member and the resin member are assembled. As a result, the lens is more firmly fixed at the correct position on the high precision member and is less likely to shift.

According to the fifth aspect of the present invention, the high-precision member made of aluminum has high dimensional accuracy and high mechanical rigidity due to the above-mentioned structure, so that twisting and distortion are less likely to occur. Also, aluminum can be easily processed into a frame by extrusion forming.

According to the sixth aspect of the present invention, the high-precision member made of a steel plate has high dimensional accuracy due to the above-mentioned structure.
Moreover, since it has high mechanical rigidity, it is difficult for twisting and distortion to occur. Further, the steel plate can be easily processed into a frame by press forming or the like.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a contact image sensor according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along the broken line a in FIG.

The frame which is the frame body of the contact type image sensor shown in FIG. 1 is made up of a high precision member 10 made of aluminum and a resin member 12 arranged to face the high precision member 10, and the high precision member 10 and the resin member 12 are provided. As will be described later, the fixing members are fixed to each other by fitting portions formed on the side plates 14 at both ends of the resin member 10 and each including a fitting member 16 and a groove 18.

When the contact image sensor of FIG. 1 is cut along the broken line a, a cross section as shown in FIG. 2 is obtained. A rod lens 22 for one line, which is an optical system for focusing the light reflected from the document surface on the light receiving element 20, is provided between the high-precision member 10 and the resin member 12 which form the frame. A document surface glass 24, which is a translucent substrate on which the document surface slides, is provided on the upper portion of the frame, and 1 is provided on the lower portion of the frame.
A light receiving element mounting substrate 26 on which the light receiving elements 20 for the lines are mounted is provided. Further, an LED array light source 28 that irradiates the original surface with light is attached to the resin member 12.

FIG. 3 is a perspective view showing only the high precision member 10 described above independently. A document surface glass reference surface 30 and a sensor reference surface 32 are provided above and below the high-precision member 10, and these define the vertical position of the document surface glass 24 and the light receiving element mounting substrate 26. Also,
A groove 34 for fitting the rod lens 22 is provided at the center of the high-precision member 10, and the vertical position of the rod lens 22 is defined by fitting and bonding the rod lens 22 into the groove 34.

The contact-type image sensor is, as described above,
In particular, the positional relationship among the original glass surface 24, the light receiving element 20, and the rod lens 22 requires high dimensional accuracy.
By the way, once an accurate mold is made of aluminum, it is possible to subsequently manufacture a large number of high-precision members 10 with accurate dimensions by extrusion molding. In this embodiment, the rod lens 22, the document surface glass reference surface 30, and the sensor reference surface 32, which are optical elements, are provided on the aluminum high-precision member 10 that is processed with high accuracy, whereby each optical element is provided. It is possible to define the mutual position of the with high accuracy. Since the LED array light source is for irradiating the original with light and does not require so high accuracy, it is provided on the resin portion 12.

Further, aluminum has a high mechanical rigidity, so that it will not be twisted or distorted even if a considerable force is applied, and it is easy to handle. Therefore, even after the frame is assembled, the accuracy of the positional relationship between the optical elements is not impaired. As shown in FIG. 2, one side of the document surface glass 22 and the light receiving element mounting substrate 26 is provided with the resin member 1
The rod lens 22 is fixed on the high precision member 1.
Since it is provided close to 0, there is no problem in the accuracy as a whole even if the resin member 12 has some dimensional error or the resin member 12 has some twist.

By the way, if a groove or a hole in a direction orthogonal to the longitudinal direction, such as a screw hole for attaching to another device, is to be provided in the extruded aluminum, it is processed in a separate process after the extrusion process. There must be. On the other hand, resin is not suitable for mounting high-precision optical elements because it is easily twisted or distorted, but the desired shape can be easily obtained by injection molding, so the above screw holes can be easily integrally molded by injection molding. it can. Therefore, in this embodiment, a portion of the frame that requires high dimensional accuracy is manufactured with the aluminum high precision member 10, and a portion of the frame that does not require such dimensional accuracy is manufactured with the resin member 12, and screw holes and the like are removed. It is integrally molded on the resin member 12.

The high-precision member 1 thus manufactured separately
0 and the resin member 12 can be easily assembled. First, the high-precision member 10 is attached to the side plate portions 14 at both ends of the resin member 12.
It is inserted into the groove 18 provided in the. When the high-precision member 10 is pushed all the way in along this groove, the high-precision member 10 stops at a predetermined position, and at the same time, the fitting member 16 causes the high-precision member 10 to move.
Is pressed toward the resin member 12 side. With this, the high precision member 1
0 and the resin member 12 are fixed to each other to form a frame. By constructing the frame from the high-precision member 10 and the resin member 12 as described above, the dimensional accuracy of the positional relationship between the optical elements can be ensured, and at the same time, the screw holes and the like, which were conventionally required for the aluminum frame, can be secured. No processing is required, and the efficiency of the entire manufacturing process can be improved. Further resin member 1
By using 2, the weight of the contact image sensor as a whole can be reduced.

As shown in FIG. 4, a convex pressing member 36 is provided at a position facing the rod lens 22 of the resin member 12 at regular intervals in the longitudinal direction. The rod lens 22 is fixed at a predetermined position on the high-precision member 10 by, for example, an adhesive. When the high-precision member 10 is inserted into the groove 18 by the pressing member 36, the rod lens 22 is attached to the high-precision member 10 side. The rod lens 22 is pressed against and plays a role of making the fixation of the rod lens 22 stronger.
Instead of integrally molding the pressing member 36 with the resin member 12 as described above, a metal spring member 38 having substantially the same length as the frame as shown in FIG. 5 is provided between the rod lens 22 and the resin member 12. It is also possible. The elasticity of the projections 38a of the spring material provided at equal intervals presses the rod lens 22 toward the high-precision member 10.

FIG. 6 is a sectional view of another embodiment of the present invention and corresponds to FIG. However, unlike FIG. 2, the document surface glass 24 is arranged so as to come to the lower side of the frame. The feature of this embodiment is that a press-formed steel plate is used as the high-precision member 40. Since the press forming of a steel plate can obtain high processing accuracy similarly to the extrusion forming of aluminum, the high-precision member 40 obtained by press forming a steel plate is also suitable as a member constituting the frame of the contact image sensor. A recess 42 for accommodating the rod lens 22 is provided at the center of the high precision member 40, and this recess 42 is also formed at the same time when the steel plate is pressed. Further, since the steel plate has high mechanical rigidity like aluminum, it is possible to effectively prevent the frame from being twisted or distorted.

FIG. 7 shows a high precision member obtained by modifying the embodiment of FIG. The high-precision member 44 of this embodiment is also formed by pressing a steel plate as in the case of FIG. 6, but the recess 42 as shown in FIG. 6 is not provided. Instead, a large number of semi-circular convex portions 46 as shown in FIG. 8 are provided by stamping at a constant interval in the longitudinal direction, thereby defining the vertical position of the rod lens 22. High precision member 44
When the frame is assembled by inserting into the groove 18 of the resin member 12, the rod lens 22 is pressed toward the high precision member 44 by the pressing member 36 of the resin member 12 or the spring member 38, and the rod lens 22 is moved to a predetermined position. Fixed.

The present invention is not limited to the above embodiments, but various modifications can be made within the scope of the invention.

[0033]

As described above, according to the first aspect of the invention, the position of the optical system, such as the original, the light receiving element, and the lens, which requires high dimensional accuracy, is defined by the high-precision member, and conventionally, Screw holes that needed to be processed in the process can be integrally molded with a resin member, and the frame can be configured easily and at low cost by combining a high-precision member and a resin member, so that the MTF does not decrease. It is possible to provide a contact image sensor that can simplify the manufacturing process.

According to the second aspect of the present invention, both ends of the high precision member are fitted into the fitting members of the side plate portions provided at both ends of the respective resin members to fix them, thereby simplifying the two. Since it is possible to assemble the frame, it is possible to provide a contact-type image sensor in which a high-precision member and a resin member are separately manufactured and assembled without complicating the manufacturing process.

According to the third aspect of the present invention, by providing the positioning portion for fixing the lens at a predetermined position on the high precision member, the lens can be easily attached, and at the time of manufacturing and after manufacturing. It is possible to provide a contact type image sensor in which dimensional error is unlikely to occur.

Further, according to the invention described in claim 4, since the pressing member is provided on the resin member, when the frame is assembled from the high precision member and the resin member, it is mounted on the high precision member. It is possible to provide a contact-type image sensor that can securely fix the lens and can effectively prevent the lens from being displaced after manufacturing.

According to the fifth aspect of the invention, by using aluminum for the high-precision member, which can be easily processed with high precision by extrusion molding or the like, there are few dimensional errors and sufficient machine It is possible to provide a contact-type image sensor having dynamic rigidity.

According to the sixth aspect of the invention, since the high-precision member is made of a steel plate which can be easily subjected to high-precision processing such as press forming, the dimensional error is small and the machine is sufficiently machined. It is possible to provide a contact-type image sensor having dynamic rigidity.

[Brief description of drawings]

FIG. 1 is a perspective view of a contact image sensor according to an embodiment of the present invention.

FIG. 2 is a view showing a cross section when cut along a broken line in FIG.

FIG. 3 is a perspective view showing a part of a high precision member to which a rod lens is attached.

FIG. 4 is a cross-sectional view showing a state in which a rod lens is pressed against a high precision member side by a pressing member on a resin member.

FIG. 5 is a perspective view of a pressing member made of a spring material.

FIG. 6 is a cross-sectional view of an embodiment of the present invention using a steel plate pressed into a high precision member.

FIG. 7 is a perspective view showing an example of a high-precision member made of a pressed steel plate.

FIG. 8 is a perspective view of a high-precision member showing a convex portion that defines the vertical position of the rod lens.

FIG. 9 is a cross-sectional view of a conventional contact image sensor.

[Explanation of symbols]

 10, 40, 44 High precision member 12 Resin member 14 Side plate portion 16 Fitting member 18 Groove 20 Light receiving element 22, 58 Rod lens 24, 52 Original surface glass 26, 54 Light receiving element mounting substrate 28, 56 LED array light source 30, 32 Reference surface 34,42 Rod lens fixing groove 36,38 Pushing member 46 Rod lens fixing convex portion 50 Frame

Claims (6)

[Claims] 1. A transparent substrate on which a document is slid, a light source for irradiating the document with light, an optical system for focusing the light from the light source reflected by the document, and the optical system. In a contact image sensor having a frame body that holds a plurality of photoelectric conversion elements that convert the focused light into an electric signal, the frame body has a relative distance between the translucent substrate and the photoelectric conversion element. A contact-type image sensor comprising a high-precision member having a prescribed reference surface and an optical system mounting surface for mounting the optical system, and a resin member for holding the light source. 2. The frame body is assembled by providing side plate portions having fitting portions at both ends of the resin member and fitting both ends of the high precision member into the respective fitting portions. Item 3. The contact image sensor according to Item 1. 3. The contact type image sensor according to claim 1, wherein a positioning portion for fixing the optical system at a predetermined position is provided on the high precision member. 4. The resin member is provided with a pressing member that presses the optical system against the high-precision member side when the resin member and the high-precision member are assembled. 2. The contact image sensor according to 2 or 3. 5. The contact type image sensor according to claim 1, wherein the high-precision member is formed by molding aluminum. 6. The contact image sensor according to claim 1, wherein the high-precision member is made of a steel plate.