JPH04314255A - Close contact type image sensor unit - Google Patents

Abstract

PURPOSE:To mount a mounting board to a mount frame with high accuracy even when the inexpensive mounting board not requiring the thin film technology to manufacture a high density pattern. CONSTITUTION:Holes 30a, 30b of a same size are made to a glass epoxy board 4 and a mount frame 12 respectively. An image sensor 2 is mounted onto the glass epoxy board 4 by using a double sided tape so that a center of a sensor element 22 comes to a position on the epoxy board 4 apart from a center axis of the hole 30a by a prescribed distance A. The mount frame 12 is processed so that a distance B from the center axis of the hole 30b of the mount frame 12 till the center of a 'SELFOC(R)' lens 8 is equal to the distance A. The holes 30a, 30b are matched and the glass epoxy board 4 and the mount frame 12 are fixed by using a pin 14.

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 unit used in an image reading device such as a small facsimile.

0002

2. Description of the Related Art Among image sensor units, a contact type image sensor unit can read a document without using a reduction optical system, so the optical path length is short and the device can be made smaller. Therefore, in recent years, they have been widely used as image reading devices such as small facsimile machines, handy scanners, and barcode readers.

[0003] In the contact type image sensor unit, an equal-magnification optical system, typified by a SELFOC lens, is used instead of a reduction optical system. In such a contact type image sensor unit, an image on a document is formed on a sensor element through a SELFOC lens to obtain a clear image.

0004

By the way, after an image sensor is mounted on a ceramic substrate or a glass substrate (mounting board), it is mounted at a predetermined position on a mounting frame. Ceramic substrates and glass substrates have high external dimensional accuracy, so by mounting the mounting board with the side surface of the mounting frame against the reference side wall of the mounting frame, it is possible to align the sensor element relative to the SELFOC lens, light source, etc. Accurate,
Moreover, it can be done easily. Thereby, a contact type image sensor unit with high resolution can be formed.

However, when a ceramic substrate or a glass substrate is used as a mounting substrate, there is a problem in that the cost increases. That is, when a ceramic substrate is used as a mounting substrate, the material cost is high, and thin film technology is required to produce a high-density pattern, which further increases the cost. In addition, when using a glass substrate,
Although the material cost is relatively low, the cost is still high because thin film technology is required to create high-density patterns.

Furthermore, when a glass substrate is used, it must be handled with care, so there is a problem that mounting and mounting operations cannot be carried out quickly.

The present invention has been made based on the above circumstances, and even if an inexpensive mounting board that does not require thin film technology is used to create a high-density pattern, the mounting board can be accurately mounted on a mounting frame. The object of the present invention is to provide a contact type image sensor unit that can perform the following steps.

[0008]

[Means for Solving the Problems] To achieve the above object, the present invention provides a mounting board on which an image sensor is mounted,
A contact image sensor unit comprising: a convergence means for converging reflected light from a document onto a sensor element of the image sensor; and a mounting frame to which the mounting board and the convergence means are mounted; a second hole corresponding to the first hole or a protrusion to be fitted into the first hole is formed in the mounting frame, and a second hole corresponding to the first hole is formed in the mounting frame; The image sensor is mounted on the mounting board so that the center of the sensor element is located at a position separated by a predetermined distance, and the image sensor is converged at a position equidistant from the central axis of the second hole or the protrusion. The convergence means is attached to the mounting frame so that the center of the means is located, and the first hole of the mounting board is aligned with the second hole or protrusion of the mounting frame. This feature is characterized by alignment with the mounting frame.

[0009] Furthermore, it is preferable that the mounting board is a glass epoxy board.

0010

[Operation] According to the above-described structure, the present invention forms a first hole in the mounting board in advance and a second hole or protrusion in the mounting frame, and extends the distance from the central axis of the first hole of the mounting board to the center of the sensor element. The image sensor is mounted on the mounting board and the focusing means is mounted on the mounting frame so that the distance and the distance from the central axis of the second hole or protrusion of the mounting frame to the center of the focusing means are the same. As a result, the first hole of the mounting board and
By aligning and fixing the second holes or protrusions of the mounting frame, the mounting board and the mounting frame can be easily aligned with high accuracy without making any additional adjustments.

[0011] Furthermore, by using a glass epoxy substrate as the mounting substrate, the first hole machining becomes easy.

0012

[Embodiment] An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a schematic cross-sectional view of a contact type image sensor unit that is an embodiment of the present invention. Note that this figure shows a cross section taken along a plane perpendicular to the main scanning direction (longitudinal direction) of the image sensor.

The contact type image sensor unit shown in FIG. 1 includes a glass epoxy substrate 4 on which an image sensor 2 is mounted.
, a linear light source 6 that emits light to the image on the document, a SELFOC lens 8 that converges the reflected light from the document onto the sensor element 22 of the image sensor 2, and a SELFOC lens 8 that protects the light source 6 and the SELFOC lens 8. The device includes a protective glass 10, an aluminum mounting frame 12 incorporating a glass epoxy substrate 4, a light source 6, a SELFOC lens 8, etc., and pins 14 for fixing the glass epoxy substrate 4 to the mounting frame 12.

The sensor element 2 is mounted on the glass epoxy substrate 4.
A driving IC (not shown) for driving the drive IC (not shown) and the like are arranged, and connection parts of the driving IC and the like are patterned. The mounting frame 12 is used not only for mounting the glass epoxy substrate 4 etc. on an image reading device such as a facsimile, but also for
It functions as a noise shield and a heat sink, and maintains the optimal operating condition of the contact type image sensor unit.

There are various types of image sensors 2, but the one used in this embodiment has a large number of sensor elements 22 arranged on a sensor substrate 24 in the main scanning direction (perpendicular to the plane of the drawing). They are arranged in a straight line. The sensor element 22 includes a photodiode that converts the reflected light from the original that is incident through the SELFOC lens 8 into an electrical signal;
It consists of a blocking diode that functions as a switching element when extracting charge corresponding to image information from each photodiode. Image information for one line in the main scanning direction is read by sequentially driving the sensor element 22 consisting of the photodiode and blocking diode.

In this embodiment, a plurality of holes 30a and 30b are formed in the glass epoxy substrate 4 and the mounting frame 12, respectively, and by aligning these two holes 30a and 30b and inserting the pin 14, the glass epoxy substrate 4 and the mounting frame 12 are formed. The epoxy board 4 is fixed to the mounting frame 12. The hole 30a serves as a reference when mounting the image sensor 2 on the glass epoxy substrate 4, and the hole 30b serves as a reference when mounting the SELFOC lens 8 into the mounting frame 12.

[0017] Conventionally, an epoxy or silicone adhesive has been used to attach an image sensor to a mounting board. Since this method requires a heat curing time of approximately 10 to 60 minutes, the substrate may warp or bend due to the difference in thermal expansion coefficient between the sensor substrate and the mounting substrate. Since a glass substrate is normally used as a sensor substrate, it has not been possible to use a glass epoxy substrate, which has a larger coefficient of thermal expansion than a glass substrate, for example, as a mounting substrate.

However, the present inventors devised a method to prevent the substrate from warping or bending by mounting the image sensor on the glass epoxy substrate using double-sided tape. In other words, when an A4 size image sensor is bonded to a glass epoxy substrate with a thickness of approximately 1.2 mm using a thermosetting adhesive, the substrate has a minimum thickness of approximately 1.0 m.
Warpage of up to approximately 5.0 mm occurs during or after manufacturing, but when an image sensor is attached to a glass epoxy substrate using double-sided tape, the substrate warps even after passing through a similar heating process. It was possible to suppress the warpage to about 0.5 mm or less. This degree of warping does not affect the performance of the contact image sensor unit in any way.
Furthermore, in constant temperature and humidity tests, thermal shock tests, etc., it was found that there was no inferiority in terms of performance compared to bonding with conventional heat-curable adhesives.

Furthermore, if the center of the sensor element 22 (in this embodiment, the center of the photodiode) is shifted from the focal point of the SELFOC lens 8, the resolution will decrease, so the center of the SELFOC lens 8 should be aligned with the center of the sensor element 22. ±0.1m
It is necessary to match with an accuracy of m. For this reason, ceramic substrates or glass substrates have conventionally been used as mounting substrates. Ceramic substrates and glass substrates can be machined with higher precision in external dimensions than glass epoxy substrates, so by placing the side of the mounting board on which the image sensor is mounted against the reference side wall of the mounting frame, the sensor element and self-lock can be easily processed. Positioning with the lens can be performed with high precision.

Even in the case of a contact type image sensor unit using a glass epoxy substrate as a mounting board as in this embodiment, this positioning can be performed with high precision as explained below.

First, holes 30a and 30b are formed in the glass epoxy substrate 4 and the mounting frame 12. Although it is not easy to finish the glass epoxy substrate 4 with high precision in external dimensions, holes can be easily made with high precision. Next, the image sensor 2 is attached to the glass using double-sided tape so that the center of the sensor element 22 (the center of the photodiode) is located a predetermined distance A from the central axis of the hole 30a provided in the glass epoxy substrate 4. It is attached to the epoxy board 4.

[0022] Furthermore, the SELFOC lens 8 has a hole 30b.
The distance B from the center axis of the SELFOC lens 8 to the center of the SELFOC lens 8 is the distance B between the center axis of the hole 30a formed in the glass epoxy substrate 4 and the sensor element 22 of the image sensor 2 attached.
the device frame 12 so that it is equal to the distance A from the center of
Attach to.

Then, the hole 30a of the glass epoxy substrate 4 on which the image sensor 2 is mounted is inserted into the hole 3 of the mounting frame 12.
By fixing them together with pins 14 in alignment with 0b, the glass epoxy substrate 4 and the mounting frame 12 can be easily aligned.

In the close-contact image sensor unit of this embodiment, the sensor element and Selfox lens are mounted in advance at predetermined positions with reference to the center axis of the hole provided in the glass epoxy substrate and the mounting frame. The sensor element can be aligned with the SELFOC lens, light source, etc. with almost the same accuracy as a mounting board using a ceramic substrate or a glass substrate.

Furthermore, since a glass epoxy substrate is used as the mounting substrate, the material cost is approximately half that of using a ceramic substrate, and thin film technology is not required for high-density pattern production, making it possible to use conventional contact image sensors. Manufacturing costs can be significantly reduced compared to units. Furthermore, handling becomes easier than when a glass substrate is used as the mounting board.

[0026] In the above embodiment, a case has been described in which a hole is formed in the mounting frame, but the present invention is not limited to this. It may also be formed by In this case, pin 14 can be omitted.

[0027]

As explained above, according to the present invention, the distance from the center axis of the first hole provided in the mounting board to the center of the sensor element and the distance between the center axis of the first hole provided in the mounting frame and the distance between the second hole or protrusion provided in the mounting frame are determined. By mounting the image sensor and the focusing means on the mounting board and the mounting frame, respectively, so that the distance from the central axis to the center of the focusing means is the same, the first hole of the mounting board and the second hole of the mounting frame are Alternatively, the mounting board can be easily and accurately mounted on the mounting frame by simply aligning and fixing the protrusions, and therefore, it is possible to use an inexpensive glass epoxy board as the mounting board. can be provided.

[Brief explanation of the drawing]

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

[Explanation of symbols]

2 Image sensor 4 Glass epoxy board (mounting board) 6
Light source 8 SELFOC lens 10 Protective glass 12 Mounting frame 14 Pin 22 Sensor element 24 Sensor board 30a, 30b Hole

Claims (2)

[Claims] 1. A mounting board on which an image sensor is mounted, a converging means for converging reflected light from a document onto a sensor element of the image sensor, and a mounting frame on which the mounting board and the converging means are mounted. In the contact image sensor unit, a first hole is formed in the mounting board, and a second hole corresponding to the first hole is formed in the mounting frame.
or a protrusion that fits into the first hole, and the image sensor is arranged such that the center of the sensor element is located a predetermined distance from the center axis of the first hole of the mounting board. mounted on the mounting board, and attaching the converging means to the mounting frame so that the center of the converging means is located at a position equidistant from the central axis of the second hole or the protrusion, A contact type image sensor unit, wherein the mounting board and the mounting frame are aligned by aligning a first hole of the mounting board with a second hole or protrusion of the mounting frame. 2. The contact image sensor unit according to claim 1, wherein the mounting board is a glass epoxy board.