JPH0646196A - Photoelectric conversion unit - Google Patents

Abstract

PURPOSE:To easily mount a photoelectric conversion unit 14 on a holder where a lens is to be installed. CONSTITUTION:Notched parts 17a and 17b for positioning are provided on a substrate 16 having a circuit pattern. By taking the notched parts as reference, a CCD chip 15 is mounted on the substrate 16. After connecting it to the circuit pattern by a wire bonding 18, the CCD chip 15 and a wire bonding 18 are coated with a light transparent resin to form a sealing resin layer 19 for protection, constructing a photoelectric conversion unit 14. When the unit 14 is mounted on the holder, the CCD chip 15 can be located at the prescribed position by performing the positioning using the notched parts 17a and 17b of the substrate 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoelectric conversion unit used for image reading.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 5, an image reading apparatus includes a feed roller 2 for feeding a document 1, a light source 3 for irradiating a reading position A of the document 1, and a light source 3 for reading the document 1. A lens 4 for forming an image of reflected light, and a photoelectric conversion element array for photoelectrically converting the reflected light formed by the lens 4 such as a CCD
Photoelectric conversion unit 5 including chip 6 and substrate 7, and holder 8 for mounting lens 4 and photoelectric conversion unit 5
When the document 1 travels through the reading position A, the reflected light at the reading position A is photoelectrically converted by the photoelectric conversion unit 5 to perform reading.

As shown in FIGS. 6 and 7, the photoelectric conversion unit 5 used here has a CCD chip 6 fixed to a ceramic substrate 9, an upper surface thereof sealed with a cover glass 10, and a large number of connections. Package 12 with terminals 11 attached
The package 12 includes a board 7 having a circuit pattern for mounting the package 12, and peripheral circuit components 13 and the like mounted on the board 7. The package 12 has its terminals 11 soldered to the board 7. As a result, they were mechanically fixed and electrically wired. Also, FIG.
As shown in FIG. 3, the photoelectric conversion unit 5 was attached by fixing the substrate 7 to the holder 8.

[0004]

However, in such a conventional photoelectric conversion unit, since the package 12 is fixed to the substrate 7 by soldering the terminals 11 of the package 12 to the substrate 7, the substrate 7 of the package 12 is fixed. Therefore, the positional accuracy of the CCD chip 6 with respect to the substrate 7 is deteriorated not only in the X and Y directions on the plane of the substrate 7 but also in the Z direction perpendicular to the plane. Therefore, when attaching the photoelectric conversion unit 5 to the holder 8, it is necessary to attach the substrate 7 to the holder 8 while adjusting the position so that the CCD chip 6 is accurately positioned at the image forming position of the lens 4. It was a big limitation for automation of assembly and maintenance of the device.
Further, since the package 12 and the board 7 are separate parts, not only the number of parts is increased, but also an operation of connecting them is required, and moreover, the package 12 is soldered to the board 12 to the board 7. It was extremely difficult to fix the parallelism while maintaining the parallelism, which also caused an increase in cost.

The present invention has been made in view of the above problems, and it is inexpensive that the photoelectric conversion element array can be positioned and fixed at a predetermined position only by positioning and fixing the substrate at a predetermined position. Another object of the present invention is to provide a new photoelectric conversion unit.

[0006]

In order to solve the above problems, the present invention forms positioning means in the X and Y directions on a substrate having a circuit pattern, and uses the positioning means as a reference on the substrate. With a photoelectric conversion element array,
A structure is provided in which wire bonding is provided to connect the photoelectric conversion element array to a circuit pattern, and a light-transmissive sealing resin layer is further formed thereon to protect the photoelectric conversion element array and the wire bonding. Is.

[0007]

According to the present invention, since the photoelectric conversion element array is positioned and fixed with respect to the substrate by the above construction, the photoelectric conversion element array is mounted on the holder holding the lens with the positioning means as a reference. The rows can be accurately positioned in the X and Y directions, eliminating the need for conventional adjustments. Further, by directly mounting the photoelectric conversion element array on the substrate, it is not necessary to solder the package to the substrate as in the conventional case, and the cost can be reduced. Furthermore, since the transparent encapsulating resin layer covers the photoelectric conversion element array and the wire bonding, sufficient durability can be provided.

[0008]

1 (a) is a schematic plan view of a photoelectric conversion unit 14 according to an embodiment of the present invention, and FIG. 1 (b) is a schematic sectional view thereof. In the figure, reference numeral 15 is a chip constituting a photoelectric conversion element array, for example, a CCD chip, and 16 is its CCD.
This is a substrate to which the chip 15 is attached. As the substrate 16, a material that is an insulator and has strength and flatness for mounting a chip and has a small characteristic change with respect to temperature and humidity changes is used. For example, ceramic is used. 17a, 17
Reference numeral b is a notch formed in the substrate 16 and constitutes a positioning means when the substrate 16 is attached. The positioning means is not limited to the notches 17a and 17b, but may be of another type, for example, a combination of a round hole and an elongated hole. In addition, the two adjacent sides of the substrate are accurately processed,
The two sides may be used as the positioning means.

The CCD chip 15 is directly mounted on the substrate 16. The mounting of the CCD chip 15 is usually
It is performed using an adhesive. At this time, the light receiving portion of the CCD chip 15 is provided with the cutouts 17a and 17b serving as the position reference of the substrate 16.
To suit. This operation can be performed by an automatic recognition and assembling apparatus using an industrial television camera. Thus,
The CCD chip 15 is provided with notches 17a, 17 on the substrate 16.
It is arranged at a predetermined position with reference to b.

A circuit pattern (not shown) is provided on the substrate 16. Reference numeral 18 is wire bonding for wiring the CCD chip 15 and the circuit pattern, and reference numeral 19 is a light-transmissive sealing resin layer formed thereon so as to protect the CCD chip 15 and the wire bonding 18. The sealing resin layer 19 can be easily manufactured by applying a liquid resin and curing it. Examples of the sealing resin include silicon resin. 20 is the substrate 1
6 is a peripheral circuit component attached to No. 6.

Next, a method of using the photoelectric conversion unit 14 configured as described above will be described. In FIG. 2, 22
Is a lens for forming an image of reflected light from the original, and 23 is a holder for holding the lens 22. This holder 23
Has positioning pins 24a, 24b and a screw hole 25, and the center of the optical axis of the lens 22 is the positioning pin 24
It is designed to be attached to a predetermined position with high precision with reference to a and 24b.

When the photoelectric conversion unit 14 is attached to the holder 23, the positioning pins 24a and 24b of the holder 23 are combined with the notches 17a and 17b of the substrate 16. As a result, the position of the light receiving portion of the CCD chip 15 with respect to the center of the optical axis of the lens 22 is very highly accurate,
Positioning is performed in the X and Y directions. Then
In order to fix the board 16, it is assembled by the fixing screw 26. After the above assembly, the focus is adjusted by the fine movement of the lens 22. With the above, the assembling operation is completed.

As described above, in the photoelectric conversion unit 14 of this embodiment, the positioning pins 24a and 24b and the notches 17a and 17b are used to position the holder 23 so that the optical axis of the lens 22 is centered. On the other hand, C
It is possible to position the light receiving portion of the CD chip 15 in the X direction and the Y direction with high accuracy.
No direction adjustment required. Therefore, the assembling work becomes extremely easy and the automation becomes possible.

FIG. 3 is a schematic plan view showing a photoelectric conversion unit 14A according to another embodiment of the present invention, FIGS. 4 (a) and 4 (b).
Shows an example of use of the photoelectric conversion unit 14A. In the photoelectric conversion unit 14A, instead of providing a cutout in the substrate 16A, the adjacent sides 16a, 1a of the substrate 16A,
6b is machined at a right angle to serve as positioning means,
With reference to the sides 16a and 16b, the CCD chip 15
Is attached in place. Other configurations are the same as those of the photoelectric conversion unit 14 shown in FIG.

On the other hand, as the object to which the photoelectric conversion unit 14A is attached, the lens 28 with a holder in which the holder and the lens are integrated is used. The holder-equipped lens 28 has a recess at one end for mounting the substrate 16A of the photoelectric conversion unit 14A, and the X-direction positioning reference surface 29X and the Y-direction positioning reference surface 29Y are formed on the side surfaces of the recess. A Z-direction positioning reference surface 29Z is formed on the bottom surface of the recess. The distances between these positioning reference planes 29X, 29Y, 29Z and the lens are kept to a predetermined accuracy in advance.

When the photoelectric conversion unit 14A is attached to the lens 28 with the holder, the surface of the substrate 16A is pressed against the positioning reference plane 29Z and the substrate 16 is also attached.
The sides 16a and 16b of A are positioned on the positioning reference plane 29, respectively.
Fix it with screws 30 while pressing it against X and 29Y. As a result, the CC attached to the board 16A
The light receiving portion of the D chip 15 is positioned with high accuracy in the X direction, the Y direction, and the Z direction with respect to the lens, and adjustment work is unnecessary in the X, Y, and Z directions.

Thus, in the embodiment shown in FIGS. 3 and 4,
No adjustment is required at the time of assembling, the assembling work becomes easier, and the automation becomes easier. Furthermore, since all the adjustments that have been conventionally performed can be omitted, when a defect occurs in the reading unit, it is not necessary to replace the entire reading block as in the conventional case, and only the photoelectric conversion unit 14A needs to be replaced. It is also possible to reduce the maintenance management cost by improving the efficiency and reducing the size and simplification of the maintenance parts.

[0018]

As is apparent from the above description, according to the present invention, positioning means in the X and Y directions are formed on a substrate having a circuit pattern, and photoelectric conversion is performed on the board with the positioning means as a reference. In addition to providing the element array, wire bonding for connecting the photoelectric conversion element array to the circuit pattern is provided, and further, a light-transmissive sealing resin is applied to protect the photoelectric conversion element array and the wire bonding. With the configuration, the structure is extremely simple compared to the conventional assembly of the package and the board, and the difficult work of soldering while keeping the package parallel to the board is unnecessary. It is easy to manufacture and has an effect that the cost can be significantly reduced.

Further, in the photoelectric conversion unit of the present invention, since the photoelectric conversion element array is positioned and fixed with respect to the substrate, when attaching it to the holder holding the lens, the substrate is fixed. By attaching the positioning means as a reference, the photoelectric conversion element array is arranged in the X direction and the Y direction.
The position of the photoelectric conversion unit can be accurately positioned, and the adjustments in the X and Y directions can be omitted. This makes it extremely easy to mount the photoelectric conversion unit and also enables automation. .

As in the embodiment shown in FIGS. 3 and 4,
If the configuration is performed not only in the X direction and the Y direction but also in the Z direction, the adjustment at the time of mounting the photoelectric conversion unit can be further simplified, the mounting work becomes easier, the maintainability is improved, and the maintenance management cost is increased. It is also possible to obtain the advantage of being able to reduce

[Brief description of drawings]

FIG. 1A is a schematic plan view of a photoelectric conversion unit according to an embodiment of the present invention, and FIG. 1B is a schematic sectional view thereof.

FIG. 2 is a schematic perspective view illustrating a state in which the photoelectric conversion unit is attached to a holder.

FIG. 3 is a schematic plan view of a photoelectric conversion unit according to another embodiment of the present invention.

4A is a schematic vertical sectional view showing a state in which the photoelectric conversion unit of FIG. 3 is attached to a lens with a holder, and FIG. 4B is a schematic horizontal sectional view thereof.

FIG. 5 is a schematic cross-sectional view showing a main part of a reading device including a conventional photoelectric conversion unit.

FIG. 6 is a schematic perspective view of a conventional photoelectric conversion unit.

FIG. 7 is a schematic sectional view thereof.

[Explanation of symbols]

 14, 14A Photoelectric conversion unit 15 CCD chip 16, 16A Substrate 17a, 17b Cutout 18 Wire bonding 19 Sealing resin layer 20 Peripheral circuit component 22 Lens 23 Holder 24a, 24b Positioning pin

Claims (1)

[Claims] 1. A substrate having positioning means in the X and Y directions, a photoelectric conversion element array mounted on the substrate with the positioning means as a reference, a circuit pattern formed on the substrate, and the photoelectric conversion element. A photoelectric conversion unit having wire bonding for connecting a row to a circuit pattern, and a light-transmissive sealing resin layer formed thereon so as to protect the photoelectric conversion element row and the wire bonding.