JPH06166212A - Image device - Google Patents

Abstract

PURPOSE:To connect a substrate mounting an image array with another substrated mounting a control circuit without a bonding agent or a flexible printed board and simultaneously carry out the electrical connection. CONSTITUTION:An image array substrate 4 is bonded with a control circuit base 6 on a base plate 2, and substrates 4 and 6 are bonded together by slip terminals 20 and 22 from both sides, and the bonding and the electrical connection of substrate 4 and 6 are carried out almost simultaneously. A positioning component 14 for bringing the base plate 2 into contact with the end face of the substrate 4 is provided and the end face of the substrate 4 is positioned.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image device such as an LED print head, a contact image sensor and a liquid crystal shutter array head.

[0002]

2. Description of the Related Art In an image device such as an LED head, a liquid crystal shutter array head, and a contact image sensor, a substrate on which an image array is mounted is fixed to a base plate with an adhesive or the like. However, it is difficult to control the thickness of the adhesive, and the height position of the substrate varies, resulting in deterioration of image quality. Furthermore, with the adhesive, the process must be stopped while waiting for the adhesive to dry and solidify. Further, the use of the adhesive makes it difficult to disassemble the image device, and makes it difficult to repair or replace the board when a defect is found after the assembly. In addition to this, the substrate has a warp, and it is difficult to eliminate the warp of the substrate with an adhesive.

The mounting accuracy of the board is examined mainly in the mounting accuracy in the height direction, and the mounting accuracy in the lateral direction of the board, that is, the positioning of the end face in the longitudinal direction of the board is hardly studied. When the mounting accuracy of the substrate in the horizontal direction decreases, the focusing performance of the lens array and the image array deteriorates, and the image quality deteriorates. Another issue is the electrical connection to the substrate. The connection method that has been conventionally used uses a flexible printed circuit board (for example, Japanese Patent Laid-Open No. 4-2 / 1992).
No. 25327), a flexible printed circuit board is expensive, and it is difficult to control soldering to electrodes provided on the circuit board.

Therefore, in order to obtain a high-quality image device at a low price, it is possible to bond the substrate to the base plate without using an adhesive, and at the same time, the problem of the warp of the substrate, the problem of positioning the end face of the substrate, There is a need to solve the electrical connection problem.

As for the related prior art, it is known that the base plate of the image device and the lens holder of the lens array are separately provided and provided (see, for example, Japanese Patent Laid-Open No. 2-273258). There is a prior application by the inventors of the present invention to press the surface of the substrate with a sandwiching piece provided on the base plate and solder the clip terminal to the electrode provided on the substrate for connection (Japanese Patent Application No. 3-34185).
No. 7). However, these prior applications propose that the clip terminal is provided only on the side along one end surface of the substrate, and the other end surface is pressed by the sandwiching piece provided on the base plate.

[0006]

It is an object of the invention of claim 1 to (1) fix a substrate on which an image array is mounted to a base plate without using an adhesive, correct the warp of the substrate, and position the end face of the substrate. , (2) Positioning and electrical connection of the board should be performed almost simultaneously, and (3) Board with the control circuit of the imager and board with the image array should be easily connected. It is in. In addition to this, the object of the invention of claim 2 is to (4) use a clip terminal having a tip divided into two parts to more securely hold the substrate.

[0007]

The image device of the present invention comprises a base plate having an alignment member provided on the upper end portion, a substrate on which an image array is mounted, and a substrate for a control circuit of the image array. The image array board is brought into close contact with the main surface, the control circuit board is brought into close contact with the other main surface, and one end surface of the image array board is brought into contact with a positioning member of the base plate to position the two. A plurality of clip terminals are provided along one end surface of the board, the two boards are combined, and a plurality of other clip terminals are provided along the other end surface of the two boards.
It is characterized in that a plurality of substrates are joined together, and the two substrates are joined together by a plurality of clip terminals from both end face sides.

[0008] Preferably, two clip terminals whose ends are bifurcated are joined in the middle, and at least a part of the clip terminals are used to more securely hold and join the substrate. As the image device, in addition to the LED head shown in the embodiment, an image device such as a liquid crystal shutter array head or a contact image sensor is used.

[0009]

According to the present invention, the board of the image array and the board of the control circuit thereof are arranged with the base plate in the middle and are connected by the clip terminals from both sides. Further, a part of the clip terminal is used for electrical connection between these boards. As a result, the flexible printed circuit board and the adhesive are not required. The board on which the image array is mounted is pressed against the base plate by the spring property of the clip terminal, and the warp is eliminated.
As a result, the focusing performance of the image device is improved. Further, since the two substrates are joined by the clip terminals from both sides, they can be joined firmly, and the warp is eliminated accordingly. Furthermore, by using a clip terminal, a mechanical connection and an electrical connection can be simultaneously made with the clip terminal. One of the end faces of the substrate of the image array is brought into contact with a positioning member provided on the base plate to position the end face. As a result, the position of the end surface of the substrate of the image array is accurately determined.

In order to more firmly hold the substrate by the clip terminal, it is preferable to use a so-called F-shaped clip whose tip is bifurcated. However, if the F-shaped branch portions are provided on the upper and lower sides of the clip terminal, the width of the clip terminal is widened, which is not suitable when high-density wiring is required as in an image device. Therefore, it is preferable that the clip terminal is divided into two, and the terminal for the image array substrate and the terminal for the control circuit are separated and connected in the middle. In this case, the clip terminals are those whose ends are bifurcated. Even when the F-type clip terminal is used, it is not necessary to divide all the clip terminals into two. In the present invention, the clip terminals are provided on both end surfaces of the board, but one terminal is, in principle, merely for connecting the boards, and can be arranged at a low pitch. Therefore, it is not necessary to divide such a clip terminal into two.

[0011]

EXAMPLES FIGS. 1 to 6 show an example of an LED head. In FIGS. 1 and 2, reference numeral 2 is a base plate, and is made of an engineering plastic such as polyphenylene sulfide or polycarbonate, which is inexpensive and has high rigidity and heat resistance and processing accuracy. 4 is a substrate of the image array,
A glass substrate or a glass-glaze ceramic substrate having a uniform thickness and a smooth surface is used. Reference numeral 6 is a board on which an image array control circuit is mounted, and an inexpensive plastic printed board is used. 8 is an LED mounted on the substrate 4
For example, about 40 arrays are arranged linearly. Further, 10 is a part of the control IC of the LED array 8. Reference numeral 12 is another control IC mounted on the substrate 6.

Reference numeral 14 is a positioning member provided on the base plate 2, and the contact portion with the upper end surface of the substrate 4 is surfaced to be a reference surface. A sandwiching piece 16 presses the main surfaces of the substrates 4 and 6. The sandwiching piece 16 may not be provided. Two
Clip terminals 0 and 22 are clip terminals 2 in the embodiment.
0 is also used as the wiring between the substrates 4 and 6, and the clip terminal 22 is used only for mechanical connection between the substrates 4 and 6. Therefore, the clip terminal 22 is called a board fixing clip. Clip terminal 2
0 is arranged in the highest density in the vicinity of the control IC 10, and has a pitch of, for example, about 1 mm. In other portions, the pitch is, for example, about 5 mm. On the other hand, for example, about 5 to 10 substrate fixing clips 22 may be provided as a whole and arranged at a large pitch. One of the clip terminal 20 and the board fixing clip 22 is preferably integrally formed with the base plate 2, or is inserted into a hole provided in the base plate 2 after the base plate 2 is formed to be integrated.

FIG. 3 shows soldering of the clip terminal 20 and the substrate electrode 30 of the substrate 4. In the figure, 32 is an insulating film, for example, a polyimide resin film is used, and 34 is a soldering part using cream solder. Clip terminals 20, 2
2 is set, then the insulating film 32 and the clip terminal 2
The cream solder is applied indiscriminately regardless of 0 or 22. Therefore, application of cream solder becomes extremely easy.
Next, when the cream solder is melted by a hot air heater or the like, the cream solder escapes from the unfamiliar insulating film 32 and concentrates on the clip terminals 20, 22 and the substrate electrode 30. Therefore, soldering can be performed simply by indiscriminately applying cream solder and heating it with a hot air heater. The insulating film 32 is for separating the common electrode of the image array 4 and its data bus, and is originally necessary for the substrate 4. Therefore, even if the insulating film 32 is provided, the number of steps does not increase. On the printed circuit board 6 side, it is not necessary to provide the insulating film 32 because the cream solder and the plastic of the circuit board 6 do not fit well.
Set the clip terminals 20 and 22 on the printed circuit board 6,
Similarly, cream solder may be applied and soldering may be performed using a hot air heater or the like. The heater is not limited to the hot air heater, and may be a non-contact type heater such as an infrared heater which can easily be locally heated.

The application of the cream solder and the soldering with the hot air heater have the effects of shortening the soldering time, improving the work efficiency, and preventing the substrate 4 from overheating. For example, heating with a soldering iron requires a heating time of 1 minute or more, but with a hot-air heater, for example, hot air of about 250 ° C. may be added for a few seconds, which has the effect of preventing deformation of the substrate 4 due to overheating.

FIG. 4 shows the completed LED head. In the figure, reference numeral 40 is a housing in which conductive particles such as metal powder are mixed with an engineering plastic such as polyphenylene sulfide or polycarbonate, and since the conductive particles are mixed, it also serves as an electrostatic shield. Four
2 is a lens array such as a self-focusing lens array, 44 is a protrusion provided on the housing 40, and 46 is a metal cover that seals the inside of the housing 40 to prevent toner and paper dust from entering, and also acts as an electrostatic shield. To do. As a result, the LED array 8, the control ICs 10, 12 and the like are protected from noise at the time of charging and developing on the photosensitive drum, and the noise generated in the LED array 8 and the like is prevented from leaking to the outside. A pressing member 48 presses the substrate 4 via the substrate 6 against a reference surface provided on the bottom surface of the protrusion 44. The pressing member 48 may not be provided.

In the assembly of the LED head of the embodiment, the substrates 4 and 6 are set on the base plate 2, and the substrate 4 is set.
The upper end surface of the above is brought into contact with the reference surface provided on the surface of the positioning member 14. Further, the substrates 4 and 6 are sandwiched and temporarily fixed by the pieces 16. Next, cream solder is applied as described above and soldering is performed with a hot air heater or the like, whereby the attachment of the substrates 4 and 6 to the base plate 2 and the electrical connection between them are completed.

FIG. 5 shows an LED for the lens array 42.
The positioning of the array 8 is shown. The ∇ mark in the figure represents the reference plane, and the number of them has nothing to do with accuracy. Since the image array substrate 4 is pressed by the clip terminals 20 and 22 from both end surfaces, the image array substrate 4 is brought into close contact with the base plate 2 and the warp and deformation are corrected. Also, the upper part of the end surface of the substrate 4 is the positioning member 1.
4 is brought into contact with a reference plane provided on the surface of the surface No. 4 and the lateral position of the image array 8 in the drawing is determined. The substrate 4 comes into contact with the reference surface provided on the bottom surface of the protrusion 44 by the force exerted on the pressing member 48 from the metal cover 46. As a result, the substrate 4 is positioned on the reference surface of the bottom surface of the protrusion 44 in a state where the warp and the deformation are corrected. The base plate 2 with respect to the housing 40 is
It is positioned by a reference surface provided on the side surface of the housing 40. In the figure, a reference surface is provided on the left side surface. On the other hand, the lens array 42 is positioned by the housing 40, and the bottom surface and one side surface thereof are positioned by the housing 40. As a result, the vertical spacing between the lens array 42 and the LED array 8 is such that the housing 40 is in contact with the reference surface provided on the bottom surface of the protrusion 44 and the bottom surface of the lens array 42.
It is determined by the reference plane provided in. As a result, the distance between the two becomes constant. The left and right positioning of the lens array 42 and the LED array 8 is determined by bringing the upper end surface of the substrate 4 into contact with a reference surface provided on the surface of the positioning member 14. The position of the positioning member 14 is determined by bringing the base plate 2 into contact with the housing 40, and the left and right positions of the lens array 42 are determined by bringing its side surfaces into contact with a reference surface provided in the housing 40. As a result, the lens array 4
The left and right positions of the image array 8 with respect to 2 are also accurately determined.

In the embodiment, the upper end surface of the substrate 4 is brought into contact with the reference surface provided on the surface of the positioning member 14. Details are shown in FIG. The substrate 4 is cut out from the side where the LED array 8 is provided by cutting with a diamond cutter or the like. Therefore, the cutting accuracy is high at the upper portion of the end surface of the substrate 4 on the side where the diamond cutter is arranged, but the cutting accuracy at the bottom portion of the substrate 4 is low and uneven. Therefore, the upper end surface of the substrate 4 having high cutting accuracy is brought into contact with the reference surface of the surface of the positioning member 14, so that the bottom surface of the end surface of the substrate 4 is not affected by the unevenness.
Positioning can be performed.

In addition to this, there is a problem of variation in height of the lens array 42. The focusing performance of the lens array 42 is
It is determined by the distance between the center of the lens array 42 in the height direction and the surface of the LED array 8. There are various variations in the height of the lens array 42. Therefore, preferably, the lens array 42 is selected according to its height, and a spacer is inserted between the housing 40 and the bottom surface of the lens array 42 so as to correct the height variation. If the error in the distance from the center of the lens array 42 in the height direction to the surface of the LED array 8 is ± 100 μm or less, this distance is set between the surface of the photosensitive drum (not shown) and the center of the lens array 42 in the height direction. A high focusing performance can be obtained if the distance is matched with. For this purpose, the variation Δ of the width of the lens array 42 in the height direction may be measured, and the mounting interval between the LED head and the photosensitive drum (not shown) may be corrected by Δ. When the distance between the surface of the LED array 8 and the center of the lens array 42 in the height direction is H, the distance between the center of the lens array 42 and the surface of the photosensitive drum (not shown) must also be H.
Here, if the thickness of the lens array 42 decreases by Δ, L
The distance between the photosensitive drum and the center of the lens array 42 in the height direction is reduced by Δ / 2.
It increases by 2 and becomes H + Δ / 2. Therefore, if the mounting distance between the LED head and the photoconductor drum is shortened by Δ, high focusing performance can be obtained without adjusting the position of the lens array 42 in the height direction with a spacer.

In order to increase the holding strength of the substrates 4 and 6,
The so-called F with the tip branched to the clip terminal 20
It is preferable to use mold clips. However, the F-shaped clip is generally wide, and its width becomes 1 mm or more.
It is not suitable for wiring in an image device that requires an array pitch of about mm. Therefore, like the clip terminal 70 of FIG.
Different clip terminals 70 and 70 are used on the substrate 4 side and the substrate 6 side, and these clip terminals are combined and used. Clip terminal 7 in FIG.
For example, 0 can be formed with a width of about 0.4 mm. It is to be noted that deformed clip terminals 80 may be used like the clip terminals 80, 80 shown in FIG. In the case of the clip terminal 80 of FIG. 8, the maximum width is 0.8
A terminal of about mm can be obtained.

9 and 10 show the connection of the substrates 4 and 6 using the clip terminal 70. In this case, the clip terminals 70 are soldered to the substrates 4 and 6, respectively, and set on the base plate 2. The lengths of the clip terminals 70, 70 are set so as to overlap each other, and the overlapping portions are crimped by using a crimp ring 72, for example. FIG. 10 shows the crimp ring 72. In this way, the clip terminals 70, 70 can be connected without heating the image array substrate 4.

FIG. 11 shows another method of connecting the clip terminals 70, 70. In this modification, a protrusion 74 is provided on the base plate 2, and an insertion hole 76 for the clip terminal 70 is provided in the protrusion 74. The width of the clip terminal insertion hole 76 is
The thickness is set to be slightly smaller than the wall thickness when the two clip terminals 70, 70 are overlapped, and a curvature is provided so that the width becomes slightly narrow at the center of the hole 76. Then, the clip terminals 70, 70 are soldered to the boards 4, 6 in advance, and the clip terminals 70, 70 are passed through the clip terminal insertion holes 76. By doing so, the clip terminals 70, 70 are pressed and closely contacted with each other because the width of the insertion hole 76 is narrow, and the width of the hole is narrowed at the center of the insertion hole 76, so that the clip terminals 70 cannot be pulled out in any of the upper and lower directions. Even in the modification of FIG. 11, the clip terminal 7 is not heated.
There is an advantage that the glass substrate 4 is not heated because the bonding between 0 and 70 is possible.

12 and 13 show the connection between the clip terminals 120 and 120 using caulking. The clip terminal 120 has a circular overlapping portion, and a small hole 128 is provided in the center thereof. The base plate 2 has a protrusion 1
22 and the caulking projection 124 are provided. The diameter of the caulking projection 124 is set to match the diameter of the hole 128 provided in the circular portion of the clip terminal 120. Also in this modification, the clip terminals 120 are soldered to the substrates 4 and 6, the clip terminals 120 and 120 are overlapped, and the caulking projection 1
Pass through 24. Next, when the caulking projection 124 is heated with ultrasonic waves or hot air, the caulking portion 126 is formed by deforming the projection. As a result, the clip terminals 120, 120 are joined and cannot be pulled out. In this modification, local heating by ultrasonic waves or the like is possible, but since heating is involved, the glass substrate 4 may be deformed, which is not preferable compared to the examples of FIGS. 9 to 11.

Alternatively, the clip terminals 70, 70 can be soldered at the overlapping portions. However, in this case, it is necessary to preliminarily thickly fill the overlapping portions of the clip terminals 70, 70 with solder, or to supply the solder from the outside at the time of soldering.
Further, since soldering requires a heating time of about 1 minute, heat may be transmitted through the clip terminal 70 and deform the glass substrate 4. Therefore, the clip terminals 70, 70
It is not preferred to bond the by direct soldering.

FIG. 14 shows an F-type clip terminal for a board fixing clip. In the figure, 140 is a board fixing clip, 142, 144, 146 and 148 are branches, and 150
Is a root portion and is to be cut off after the substrates 4 and 6 are joined. In this board fixing clip 140, for example, a branch 142
And 144 are used to connect to the substrate 4, and the branches 146 and 148 are used to connect to the substrate 6. As is clear from the figure, the maximum width A of the board fixing clip 140 is large, for example 1.6.
It is about 2 mm, which is not suitable for high-density wiring. However, about 5 to 10 board fixing clips 140 may be provided, and the board fixing clips 140 as shown in FIG. 14 can be used since they can be arranged at a low pitch.

[0026]

According to the invention of claim 1, (1) the substrate on which the image array is mounted is bonded to the base plate without an adhesive, the warp of the substrate is corrected, and the end face of the substrate is positioned to improve the focus performance. It is possible to improve (2) the positioning and electrical connection of the board almost at the same time, simplify the assembly, improve the positioning accuracy, and (3) eliminate the need for the flexible printed board for the connection. Claim 2
In addition to this, in the invention of (4), (4) the connection between the clip terminal and the substrate can be made stronger. Moreover, the clip terminals can be arranged at a high density, and can be adapted to an image device that requires high-density wiring.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part of an image device according to an embodiment.

FIG. 2 is a cross-sectional view of the main part of the image device according to the embodiment.

FIG. 3 is a side view of a main part showing a soldering part in the embodiment.

FIG. 4 is a sectional view of the image device according to the embodiment.

FIG. 5 is a diagram showing positioning of the image device according to the embodiment.

FIG. 6 is a diagram showing positioning of a substrate end surface in the image device of the embodiment.

FIG. 7 is a diagram showing a clip terminal used in an example.

FIG. 8 is a diagram showing a modified clip terminal.

FIG. 9 is a sectional view of an essential part showing the connection of two clip terminals in the embodiment.

FIG. 10 is a side view of a main portion showing a connecting portion of two clip terminals in the embodiment.

FIG. 11 is a sectional view of an essential part showing a connection of two clip terminals in a modified example.

FIG. 12 is a cross-sectional view of an essential part showing the connection of two clip terminals in another modification.

FIG. 13 is a side view of a main portion showing a connecting portion of a clip terminal according to another modification.

FIG. 14 is a view showing a board fixing clip terminal of a modified example.

[Explanation of symbols]

 2 base plate 4 image array board 6 control circuit board 8 LED array 10 control IC 12 control IC 14 positioning member 16 sandwiching piece 20 clip terminal 22 board fixing clip 30 board electrode 32 insulating film 34 soldering section 40 housing 42 lens array 44 protrusion 46 Metal cover 48 Pressing member 70 Clip terminal 72 Crimping ring 74 Protrusion 76 Clip terminal insertion hole 80 Clip terminal 120 Clip terminal 122 Protrusion 124 Caulking protrusion 126 Caulking portion 128 hole 140 Board fixing clip 142, 144, 146, 148 Branch 150 Root portion

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical indication H01L 27/15 8934-4M 33/00 N 7376-4M H04N 1/028 Z 8721-5C 1/036 A 8721-5C

Claims (2)

[Claims] 1. A base plate having an alignment member provided on an upper end portion thereof, a substrate on which an image array is mounted, and a control circuit substrate of the image array, wherein the image array substrate is provided on one main surface of the base plate. And the control circuit board in close contact with the other main surface, and one end surface of the image array board is brought into contact with the alignment member of the base plate to position it, and one end surface of the two boards is attached. A plurality of clip terminals are provided along the two boards to join the two boards, and another clip terminal is provided along the other end surface of the two boards to join the two boards. An image device characterized in that a plurality of substrates are connected to each other from both end faces by a large number of clip terminals. 2. The image device according to claim 1, wherein at least a part of the clip terminal is formed by connecting two clip terminals having two ends branched off in the middle.