JPH08282007A - Image device - Google Patents

Abstract

PURPOSE: To provide an image device which can be used as an image forming device and an image reading device for a long time by connecting an electrode to an image element array firmly. CONSTITUTION: In an image device, an image element member 1 and a lens member 4 are arranged fixedly. The image element member 1 is formed by connecting an electrode 3b adhered on an image element array 3 to an electrode wire 2a adhered to a base plate 2 by flip chip connection and the lens member 4 consists of a plurality of lenses 8. A center line average roughness (Ra) regulated in JIS-B-0601 of a surface to which the electrode 3b of the image element array 3 is to be adhered is set to be 0.05μm<=Ra<=0.5μm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus used in an image forming apparatus such as an optical printer head or an image reading apparatus such as an image sensor.

[0002]

2. Description of the Related Art A conventional image forming apparatus, for example, an image forming apparatus used in an image forming apparatus such as an optical printer head, usually has a lens made of a resin such as polycarbonate in which a plurality of lenses are linearly arranged and supported at predetermined intervals. The plate and the base plate made of aluminum oxide sintered body or glass in which a large number of light emitting diode element arrays are linearly mounted are arranged so that each lens and each light emitting diode element array have a one-to-one correspondence. It has a fixed structure, and each light emitting diode element of each light emitting diode element array is caused to selectively emit light in response to an external electrical signal, and the light emitted by the light emitting diode element is passed through a lens. An image is formed on an external photoconductor, and a latent image is formed on the photoconductor to function as an image forming apparatus.

A light-emitting diode element array linearly arranged and mounted on the base plate generally has 64 light-emitting diode elements linearly arranged therein, which is suitable for a B4 size image forming apparatus. When used, the 32 light emitting diode element arrays are mounted on the base plate so that each of the 32 light emitting diode element arrays has a one-to-one correspondence with each lens.

Further, in the light emitting diode element array linearly arranged and mounted on the base plate, each electrode thereof is electrically connected to an electrode wiring previously attached to the surface of the base plate through a bonding wire, By connecting the electrode wiring on the surface of the base plate to an external electric circuit, the light emitting diode element of each light emitting diode element array is connected to the external electric circuit via the electrode wiring and the bonding wire.

[0005]

However, in this conventional image device, each electrode of the light emitting diode element array is connected to the electrode wiring of the base plate through a bonding wire, and the number of electrodes of the light emitting diode element array is Since it is extremely large, it takes a long time to electrically connect the electrodes of the light-emitting diode element array to the electrode wiring of the base plate, and the manufacturing workability of the image device is poor, and the image device as a product has the disadvantages of being expensive. Was there.

In the above embodiment, the image forming apparatus used in the image forming apparatus such as the optical printer head has been described as an example. However, in the image reading apparatus such as the image sensor using the solid-state image sensor array, etc. The image device used has the same drawbacks.

Therefore, in order to solve the above-mentioned drawbacks, the applicant of the present application connected the electrodes adhered to the surface of the preceding image element array to the electrode wiring adhered to the surface of the base plate by flip-chip connection via solder or the like. An image device was proposed.

According to such an image device, since the electrodes of the image element array are connected to the electrode wirings attached to the base plate by flip chip connection, even if the number of electrodes of the image element array is large, all of them are the electrode wirings of the base plate. Then, the electric connection is made firmly at once and, as a result, the productivity of the image device becomes extremely excellent.

However, in this image device, since the surface of the image element array is extremely smooth, the image element array and the electrodes are flat and the bonding strength is slightly weak. Therefore, when this is used as an image forming apparatus or an image reading apparatus, when heat at the time of use is applied to the base plate and the image element array, thermal stress due to the difference in thermal expansion coefficient between the base plate and the image element array is generated between them. The thermal stress repeatedly acts on the electrodes of the image element array to separate the electrodes from the image element array, resulting in the loss of the functions of the image forming apparatus and the image reading apparatus.

[0010]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned drawbacks, and an object of the invention is to firmly bond electrodes to an image element array and to use it as an image forming apparatus or an image reading apparatus for a long period of time. An object is to provide an image device.

[0011]

SUMMARY OF THE INVENTION The present invention comprises a plurality of lenses, and an image element member in which electrodes attached to an image element array are connected to electrode wirings attached to a base plate by flip-chip connection. An image device in which a lens member and a lens member are fixed together, and the surface of the image element array on which the electrodes are adhered has a center line average roughness (Ra) defined in JIS-B-0601 of 0.05 μm ≦ Ra ≦ 0.5 μm
It is characterized by being.

[0012]

According to the image device of the present invention, the area on the surface of the image element array where the electrodes are applied has a center line average roughness (Ra) specified in JIS-B-0601 of 0.05 μm ≦ Ra ≦
Since the image element array and the electrodes are joined three-dimensionally and firmly because of the appropriate roughness of 0.5 μm, the electrodes of the image element array are always firmly flip-chip connected to the electrode wiring of the base plate, and the image is It can be used for a long period of time as a forming device or an image reading device. Further, according to the image device of the present invention, the electrodes of the image element array are connected to the electrode wirings of the base plate by flip-chip connection, so that even if the number of electrodes of the image element array is large, all of them are simultaneously attached to the electrode wirings of the base plate. In addition, since the electric connection is made firmly, the image device as a product becomes inexpensive.

[0013]

The present invention will now be described in detail with reference to the accompanying drawings. 1 to 3 show an embodiment in which the image device of the present invention is applied to an optical printer head as an image forming device, 1 is an image element member, 2 is a light emitting diode element array, and 4 is a lens member. .

The image element member 1 comprises a base plate 2 and a large number of light emitting diode element arrays 3, and the base plate 2 is made of an electrically insulating material such as an aluminum oxide sintered body, crystallized glass, quartz or glass epoxy resin. , A plurality of light emitting diode element arrays 3 on its lower surface
Are arranged linearly.

The base plate 2 functions as a support member for supporting the light emitting diode element array 3, and as shown in FIG. 3, the electrode wiring 2a attached to the base plate 2 is flipped with each electrode 3b of each light emitting diode element array 3. Chip connection, specifically, the light emitting diode element array 3 on the surface of the base plate 2, the electrode wiring 2a attached to the base plate 2 and each electrode 3b of the light emitting diode element array 3 face each other with the solder 5 interposed therebetween. In this manner, the solder 5 is heated and melted, and the electrode wirings 2a of the base plate 2 and the electrodes 3b of the light emitting diode element array 3 are solder-bonded to each other, so that each light emitting diode element array 3 is attached to the base plate. 2 is arrayed and mounted on the lower surface. Further, at this time, even if the total number of the electrodes 3b of each light emitting diode element array 3 is extremely large, all of the electrodes 3b are firmly fixed to the electrode wirings 2a attached to the surface of the base plate 2 at once through solder. Since they are electrically connected, each electrode 3b of the light emitting diode element array 3 and the electrode wiring 2a of the base plate 2 can be electrically connected in an extremely short time, and the workability and the productivity of assembling the image device are increased. improves.

The base plate 2 is made of an aluminum oxide sintered body, crystallized glass, quartz, glass epoxy resin, liquid crystal polymer resin, or the like. An opening is provided in the portion, the opening serves as a window portion for forming a light passage between the light emitting diode element array 3 and the lens 8 of the lens member 4 described later, and is made of a transparent material such as crystallized glass or quartz. In that case, the central region of the light emitting diode element array 3 serves as a window for forming a light passage between the lens element 8 and the lens 8.

When the base plate 2 is made of an opaque material such as an aluminum oxide sintered body, each light emitting diode element of each light emitting diode element array 3 is formed by making a hole in the central portion of the base plate 2 using a laser or the like. An opening serving as a window portion for transmitting the light emitted by 3a to the lens 8 side is formed in a predetermined shape.

Further, the electrode wiring 2a attached to the surface of the base plate 2 has a function of connecting each electrode 3b of the light emitting diode element array 3 to an external electric circuit, and the surface of the base plate 2 is made of aluminum, copper or the like. The surface of the base plate 2 is formed by applying a conductive material to a predetermined thickness by a plating method, a vapor deposition method, a sputtering method or the like, processing this into a predetermined pattern by an etching method, and then applying nickel plating and gold plating to the surface. It is deposited on.

Further, the solder 5 for connecting the electrode wiring 2a previously deposited on the surface of the base plate 2 and each electrode 3b of the light emitting diode element array 3 is previously coated on the surface of the electrode wiring 2a to a predetermined thickness by solder plating. If it is attached, the electrode wiring 2a of the base plate 2 and each electrode 3b of the light emitting diode element array 3 are automatically arranged between the electrode wiring 2a and the electrode 3b only by facing each other, and are attached to the base plate 2. The workability of flip-chip connection between the electrode wiring 2a and each electrode 3b of the light emitting diode element array 3 becomes extremely simple. Therefore, it is preferable that the solder 5 for connecting the electrode wiring 2a previously attached to the surface of the base plate 2 and the light emitting diode element array 3 is previously applied to the surface of the electrode wiring 2a to a predetermined thickness by solder plating. .

Furthermore, the light emitting diode element array 3 arranged and mounted on the base plate 2 comprises a plurality of light emitting diode elements 3a.
a selectively emits light individually in response to an external electric signal, and irradiates the photoconductor P with the emitted light to form a latent image for forming an image on the photoconductor P.

The light emitting diode element 3a is a GaAsP type,
GaP-based light-emitting diodes are used.For example, in the case of GaAsP-based light-emitting diodes, first, the GaAs substrate is heated to a high temperature in a furnace and AsH ₃ (arsine) and PH ₃ (
A single crystal of n-type semiconductor GaAsP (gallium-arsenic-phosphorus) is grown on the substrate surface by contacting a gas containing an appropriate amount of phosphine) and Ga (gallium), and then Si ₃ is grown on the GaAsP single crystal surface.
A windowed film of N ₄ (silicon nitride) is deposited, and Zn (zinc) gas is exposed to the window to form an n-type semiconductor GaAsP.
Zn is diffused into a part of the single crystal to form a p-type semiconductor, and pn
It is formed by providing a bond.

In the case of the B4 size optical printer head, the number of the light emitting diode elements 3a is 2048 (8 per 1 mm).
Are arranged in a straight line. Specifically, 32 light emitting diode element arrays 3 each having 64 light emitting diode elements 3a as a unit, and 2048 light emitting diode elements 3a by linearly arranging Are arrayed and mounted on the base plate 2.

As shown in FIG. 3, in the light emitting diode element array 3, the area A on the surface of which the electrode 3b is deposited has a center line average roughness (Ra) specified by JIS-B-0601. The roughness is 05 μm ≦ Ra ≦ 0.5 μm. For this reason, when the electrodes 3b are joined to the light emitting diode element array 3, the joining between them becomes three-dimensionally strong, whereby the electrodes 3b of the light emitting diode element array 3 are firmly flip-chip connected to the electrode wiring 2a of the base plate 2. Thus, the image forming apparatus can be used for a long period of time. The surface roughness of the light emitting diode element array 3 has a center line average roughness (Ra) of 0.0.
When 5 μm> Ra, the surface of the light emitting diode element array 3 becomes smooth and the electrodes 3b cannot be firmly joined, and when 0.5 μm <Ra, the mechanical strength of the light emitting diode element array 3 is greatly reduced. , It is easily damaged when an external force is applied. Therefore, the surface roughness of the light emitting diode element array 3 is 0.05 μm ≦ Ra ≦ in terms of center line average roughness (Ra) specified in JIS-B-0601.
It is specified in the range of 0.5 μm.

Further, the base plate 2 on which the light emitting diode element array 3 is arrayed and mounted is provided with a lens member 4 above the base plate 2 with a certain distance therebetween.
Is composed of a lens plate 7 in which a plurality of holes are linearly arranged and a lens 8 which is adhered and fixed to the lens plate 7 with an adhesive such as resin so as to close the holes.

The lens plate 7 of the lens member 4 acts as a support member for supporting a plurality of lenses 8 on the upper surface at a predetermined interval, and the holes allow the light emitted by each light emitting diode element 3a of the light emitting diode element array 3 to be emitted. It has the function of transmitting light to the lens 8. The lens plate 7 is formed of a material such as glass epoxy resin.

Each lens 8 supported by the lens plate 7 has a function of irradiating the surface of the photoconductor P with light emitted from each light emitting diode element 3a, and is made of a transparent resin such as an acrylic resin or a polycarbonate resin, or glass. A lens formed of the transparent inorganic material is preferably used.

The lenses 8 are linearly adhered to the lens plate 7 at predetermined intervals by adhering a part of the outer surface to the lens plate 7 via an epoxy resin adhesive, for example.

Furthermore, the base plate 2 on which the light emitting diode element array 3 is mounted and the lens member 4 having a plurality of lenses 8 are fixed to the spacers 9, so that each light emitting diode element array 3 and each lens 8 are fixed.
And are placed side by side so as to correspond one-to-one with a predetermined distance.

The spacer 9 has a first alignment reference surface 9a at its upper portion and a second alignment reference surface 9b at its lower portion, and the first alignment reference surface 9a of the spacer 9 has a lower surface of the lens plate 7. By fixing the outer peripheral portion of the upper surface of the base plate 2 to the second alignment reference surface 9b so that each light emitting diode element array 3 and each lens 8 are in a one-to-one correspondence with a predetermined distance therebetween. Has become. The spacer 9 is made of, for example, the same material as the base plate 2 and the lens plate 7.

Thus, according to the image device of the present invention, a predetermined power is applied to each light emitting diode element 3a to cause each light emitting diode element 3a to individually and selectively emit light, and the light emitted by each light emitting diode element 3a is emitted. Is formed on the surface of the external photoconductor P via the lens 8 to form a predetermined latent image on the photoconductor P, thereby functioning as an image forming apparatus.

The present invention is not limited to the above-mentioned embodiments, and various modifications can be made without departing from the scope of the present invention. For example, in the above-mentioned embodiments, the optical printer head, etc. However, the light emitting diode element array may be replaced with a solid-state image pickup element array to be used in an image reading apparatus such as an image sensor.

[0032]

According to the image device of the present invention, the area on the surface of the image element array where the electrodes are attached is defined by JIS-B-06.
The center line average roughness (Ra) specified in 01 is 0.05 μm ≦
The moderate roughness of Ra ≦ 0.5 μm makes the connection between the image element array and the electrode three-dimensional and strong, whereby the electrode of the image element array is always firmly flip-chip connected to the electrode wiring of the base plate. Therefore, it can be used as an image forming apparatus or an image reading apparatus for a long period of time. Further, according to the image device of the present invention, the electrodes of the image element array are connected to the electrode wirings of the base plate by flip-chip connection, so that even if the number of electrodes of the image element array is large, all of them are simultaneously attached to the electrode wirings of the base plate. In addition, since the electric connection is made firmly, the image device as a product becomes inexpensive.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment in which an image forming apparatus of the present invention is applied to an optical printer head as an image forming apparatus.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is an enlarged cross-sectional view of a main part of the image device shown in FIG.

[Explanation of symbols]

 1 ... Image element member 2 ... Base plate 2a ... Electrode wiring 3 ... Light emitting diode element array 3a ... Light emitting diode element 3b ... ..Electrode 4 ... Lens member 7 ... Lens plate 8 ... Lens 9 ... Spacer P ..

Claims (1)

[Claims] 1. An image element member formed by connecting an electrode attached to an image element array to an electrode wiring attached to a base plate by flip-chip connection, and a lens member including a plurality of lenses are fixed together. Image device, wherein the surface on which the electrodes of the image element array are deposited is JI
An image device characterized in that the center line average roughness (Ra) specified by S-B-0601 is 0.05 μm ≦ Ra ≦ 0.5 μm.