JP2002223000A - Optical printer head and method for manufacturing it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical printer head which can restrain the image formation of an abnormal dot generated when the width size of a light emitting element array is small and which can output a satisfactory picture quality, and to provide a method for manufacturing it. SOLUTION: The optical printer head is provided with a plurality of first- conductivity semiconductor blocks which are isolated in element from each other, a plurality of second-conductivity semiconductor regions 13 formed in the semiconductor blocks, matrix interconnections which connect the prescribed semiconductor regions 13 formed in the semiconductor blocks and a second- conductivity pad electrode 5 which is connected to the matrix interconnections. The pad electrode 5 is provided with the light emitting element array 1 in which the multilayered pad electrode 5 is formed on the matrix interconnections, a drive circuit which individually drives the semiconductor regions 13 and bonding wires 104a which electrically connect the pad electrode 5 to the drive circuit. The optical printer head comprises a structure in which the component of light at a radiation angle of within 60 deg. from among the component of light radiated from the semiconductor regions 13 is not incident on the bonding wires 104a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical printer head and a method for manufacturing the same, which can suppress the formation of abnormal dots caused by reducing the width of a light emitting element array.

[0002]

2. Description of the Related Art In recent years, as digital image output devices such as digital copiers, printers, and digital facsimile machines have become smaller, optical writing units for performing digital writing have been required to be smaller. As a method of performing digital writing, there are an optical scanning method in which a light beam emitted from a light source such as a semiconductor laser is optically scanned by an optical deflector and a light spot is formed by a scanning image forming lens, and a light emitting diode (LE).
D) There is a solid-state writing method in which a light beam emitted from a light emitting element array such as an array or an organic EL array is used to form a light spot by an imaging element array. The optical scanning method scans light with an optical deflector, so the optical path length becomes longer.
The solid-state writing method is suitable for downsizing an optical writing unit because the optical path length can be very short. L
A printer head using an ED array is called an LED printer head, which includes an LED array and a driving circuit for individually driving LEDs on the LED array on a mounting substrate.

Japanese Patent Application Laid-Open No. 11-40842 discloses a conventional light emitting element (LED) array in which a p-side pad electrode and a matrix wiring are formed in separate areas, and a p-side pad electrode and a matrix wiring. A light emitting element array, a method of manufacturing the same, and a light emitting element array in which the width of the light emitting element array is reduced by the width of the p-side pad electrode (or the width of the matrix wiring formation region) There is disclosed a printer head using the same.

The light emitting element array disclosed in Japanese Patent Application Laid-Open No. H11-40842 will be described below. FIGS. 7A to 7D are views showing the structure of the light emitting element array disclosed in Japanese Patent Application Laid-Open No. H11-40842. FIG. 7A is a plan view of the LED array 1 in which electrodes are arranged on both sides of the light emitting unit. FIG. 7B is a cross-sectional view taken along the line AA ′ in FIG. LED array 1 is 1200 DPI
(Dot Per Inch) Compatible Matrix LE
A high-resistance semiconductor substrate 2, an n-type semiconductor block 11, interlayer insulating films 12a, 12b, and 12c;
It has a p-type semiconductor region (light emitting portion) 13, individual matrix wiring 14 and common matrix wiring 4 constituting a matrix wiring, a p-type pad electrode 5, a p-type pad wiring 6, and an n-type pad electrode 15. Become. n-type semiconductor block 1
M (M is a positive integer) 1 is arranged in one row on the high resistance semiconductor substrate 2. FIG. 7A shows an example where M = 3. The n-type semiconductor block 11 is obtained by dividing an n-type semiconductor layer such as an epitaxial layer formed on a high-resistance semiconductor substrate 2 by an isolation groove 3. Therefore, the n-type semiconductor block 11 is element-isolated from each other by the high-resistance semiconductor substrate 2 and the separation groove 3. Each n-type semiconductor block 11 has a p-type semiconductor region 1 formed by a diffusion method or the like.
3 (N is a positive integer) are formed in one row. FIG.
(A) shows an example where N = 5. One p-type semiconductor region 13 and n-type semiconductor block 11 are connected to one LED
Is configured. That is, N-type semiconductor block 11 has N
LEDs are formed. The depth of the p-type semiconductor region 13 is smaller than the thickness of the n-type semiconductor block 11. Therefore, the p-type semiconductor region 13 is formed in the n-type semiconductor block 11 in a floating island shape.

A first interlayer insulating film 12a is formed on the n-type semiconductor block 11 in which the p-type semiconductor region 13 has been formed. In the first interlayer insulating film 12a, a light-emitting opening 16 exposing substantially the entire surface of the p-type semiconductor region 13;
A pad opening 17 for exposing the surface of the n-type semiconductor block 11 is formed. On the n-type semiconductor block 11 on which the first interlayer insulating film 12a is formed, N individual matrix wirings 14 and n-type pad electrodes 15 are formed. The individual matrix wirings 14 are individually in contact with the p-type semiconductor regions 13 at the light emitting openings 16. The n-type pad electrode 15 is formed in the pad opening 17 and is in contact with the n-type semiconductor block 11.

A second interlayer insulating film 12b is formed on the n-type semiconductor block 11 on which the individual matrix wiring 14 and the n-type pad electrode 15 are formed. In the second interlayer insulating film 12b, a light emitting opening 16 exposing substantially the entire region of the p-type semiconductor region 13, a pad opening 17 exposing the n-type pad electrode 15, and a matrix via exposing the individual matrix wiring 14 are provided. A hole 18 and a pad via hole 19 are formed. The matrix via hole 18 is for contacting the individual matrix wiring 14 and the common matrix wiring 4, and the pad via hole 19 is for connecting the p-type pad electrode 5 to the matrix wiring. The n-type semiconductor block 11 on which the second interlayer insulating film 12b is formed has P
(P is an integer equal to or greater than N) common matrix wirings 4 are formed. FIG. 7A shows an example where P = 5.
The common matrix wiring 4 is formed over all the n-type semiconductor blocks 11, and contacts a predetermined individual matrix wiring 14 in a matrix via hole 18.

Further, a third interlayer insulating film 12 is formed on the n-type semiconductor block 11 on which the common matrix wiring 4 is formed.
c is formed. The third interlayer insulating film 12c includes
A light-emitting opening 16, a pad opening 17, and a pad via hole 19 are formed. Third interlayer insulating film 12
On the n-type semiconductor block 11 on which c is formed, a p-type pad electrode 5 and a p-type pad wiring 6 are formed. p
The mold pad electrode 5 and the p-type pad wiring 6 are formed integrally. The p-type pad electrode 5 is formed on the common matrix wiring 4 via the third interlayer insulating film 12c, and is connected to a predetermined individual matrix wiring 14 via the p-type pad wiring 6. The p-type pad wiring 6 is in contact with a predetermined individual matrix wiring 14 in a pad via hole 19. FIG. 7A shows an example in which two p-type pad electrodes 5 are formed on each n-type semiconductor block 11.

The LED array 1 has a p-type pad electrode 5 and an n-type pad electrode 5.
When a voltage is applied between the mold pad electrodes 15, a light-emitting phenomenon occurs at the junction surface between the p-type semiconductor region 13 and the n-type semiconductor block 11, and the emitted light is emitted to the outside from the surface of the p-type semiconductor region 13 . As shown in FIG. 7B, the light emitted from the p-type pad 13 is emitted vertically upward from the surface of the p-type semiconductor region 13.

In the conventional LED array, the p-type pad electrode and the matrix wiring are formed in separate regions without forming a multilayer structure.
And the matrix wiring (here, the individual matrix wiring 14
And the common matrix wiring 4) have a multilayer structure, and the p-type pad electrode 5 is formed on the matrix wiring.
The width of the array 1 can be reduced by the width of the p-type pad electrode 5 (or the width of the matrix wiring formation region).

FIG. 7C is a plan view of the LED array 51 in which the electrodes are arranged on one side of the light emitting section, and FIG.
FIG. 8 is a sectional view taken along the line AA ′ in FIG. FIG.
In FIG. 7C, the same elements as those in FIG. 7A are denoted by the same reference numerals. The LED array 51 includes an n-type contact electrode 52, a contact opening 53, and an n-type pad wiring 54.
And the position of the n-type pad electrode 55 is different from that of the LED array 1 of FIG. The LED array 51 is characterized in that the n-type contact electrode 52 is formed on the same side as the n-type pad electrode 55 with respect to the p-type semiconductor region 13.

FIG. 8A is a sectional view showing the structure of an LED printer head using the LED array 1 of FIG. 7A. The LED printer head shown in FIG. 8A includes an LED array 1 on a mounting board 201 and a driving circuit (a driving IC 2).
02 and the scanning pattern 203). LED
The p-type pad electrode 5 of the array 1 is electrically connected to the drive IC 202 by a bonding wire 204a on one side in the width direction of the LED array 1, and the n-type pad electrode 15 is on the other side in the width direction of the LED array 1. It is electrically connected to the scanning pattern 203 by a bonding wire 204b.

FIG. 8B is a sectional view showing the structure of an LED printer head using the LED array 51 of FIG. 7C. 8B, the same elements as those in FIG. 8A are denoted by the same reference numerals. The LED printer head shown in FIG. 8B uses the LED array 51 in which the n-type contact electrode 52 is formed on the same side as the n-type pad electrode 55 with respect to the p-type semiconductor region 13 so that the bonding wire 204 a 204b is drawn out from one side in the width direction of the LED array 51. Therefore, FIG.
The width of the LED printer head shown in FIG. 8B is smaller than that of the LED printer head shown in FIG.

Next, a description will be given of wire bonding used for connecting an electrode and a drive circuit when manufacturing an optical printer head. FIG. 9 is a schematic diagram showing that the first bonding point 34 and the second bonding point 35 on the bonding stage 33 are wire-bonded using the bonding wires 14.
FIG. 10 is a schematic explanatory view showing a wire bonding step by a ball bonding method used in the wire bonding shown in FIG. The process of wire bonding by the ball bonding method is as follows. First, a ball 15 is formed at the tip of the bonding wire 14 passed through the capillary 30 by using a high-voltage spark (a). Next, the ball 15 is pressed against the electrode 12 on the chip 10 by the capillary 30, and at the same time, ultrasonic waves are applied to the capillary 30. At this time, the ball 15 is pressed against the electrode 12 by pressure, ultrasonic waves and heat,
At the bonding point 34, a bonding portion like a crushed ball is formed (b). Further, the capillary 30 is moved in the direction of the second bonding point 35. At this time, the bonding wire 14 extending upward from the first bonding point 34 bends toward the second bonding point 35 (c). Finally, the bonding wire 14 is pressed against the second bonding point 35 by the capillary 30, and at the same time, ultrasonic waves are applied to the capillary 30. At this time, the bonding wire 14 is pressed against the second bonding point 35 by pressure, ultrasonic waves, and heat. At the second bonding point 35, a fan-shaped bonding portion formed by crushing the bonding wire 14 is formed ( d). The diameter of the bonding wire needs to be 18 to 20 μm even when it is small. Therefore, a hemispherical bonding portion having a diameter of about 60 to 75 μm and a height of about 50 to 60 μm is formed at the first bonding point 34. The bonding wire 14 rises vertically from the bonding portion on the first bonding side, and rises obliquely from the bonding portion on the second bonding side.

As a wire bonding method, there is a wedge bonding method in addition to the ball bonding method shown in FIG. In the case of the wedge bonding method, the first
The wire bonding process on the bonding side and the second bonding side are the same as the processes on the second bonding side in the ball bonding method. That is, the bonding wire is directly crushed by the capillary and pressed against the bonding portion. Therefore, in the case of the wedge bonding method, the bonding wire rises obliquely from the bonding portion on both the first bonding side and the second bonding side.

Next, the state of light emitted from the light emitting section on the LED array element will be described. Generally, in an LED array element used for an optical printer head, FIG.
As shown in (a), the light emitted from the light emitting part 111b on the LED array element 111a is emitted almost vertically upward on the surface of the light emitting part 111b, and the emission pattern is Lambert distribution (complete diffusion type distribution). Spread according to. L
The radiation angle is defined as an index indicating the distribution of light emitted from the light emitting unit 111b on the ED array element 111a. The emission angle is defined as the emitted light and the light passing through the light emitting portion 111b and the LED.
Axis 111 standing perpendicular to the surface of array element 111a
is an angle formed by c and is indicated by a symbol θ. In the emission pattern of the Lambert distribution, assuming that the intensity of light emitted vertically upward (radiation angle θ is 0 degree) is 1, the intensity of light emitted in the direction of radiation angle θ of 60 degrees is about 0.5. Becomes Figure 1
FIG. 1B is a schematic diagram showing the relationship of the light intensity distribution in the printer head. Generally, the aperture angle of an optical element for imaging used in a printer head is about 20 degrees. Therefore, most of the light emitted from the LED, which is the light emitting unit, is emitted in a direction horizontal to the vertical direction, and does not contribute to image formation. In the past, most of the light that did not contribute to imaging was scattered, absorbed, and attenuated in the optical printer head.

[0016]

However, in the case of the optical printer head disclosed in Japanese Patent Application Laid-Open No. H11-40842, since the width of the LED array is small, the distance between the p-type semiconductor region (light emitting portion) and the bonding wire is small. Distance becomes shorter. Therefore, a part of the light emitted from the light emitting part is reflected or scattered on the surface of the bonding wire and then enters the imaging lens, and these lights are imaged as abnormal dots. FIG. 12 shows a light-emitting unit having a size of
It is a sectional view of an optical printer head using an LED array having a wiring width of 10 μm, a chip width of 200 μm, and a bonding wire diameter of 20 μm, wherein (a) is an LED array having electrodes on both sides of a light emitting portion, and (b) is The case where the LED array has an electrode on only one side of the light emitting unit is shown. FIG.
In order to observe the image formation state of the light beam at the position corresponding to the photoconductor, the light beam emitted from the LED array is imaged when all the light emitting units on the LED array are turned on. It is a schematic diagram of a lighting state in a corresponding position. The imaging of the light beam is performed on the upper and lower sides of the paper with the regular dots 13a therebetween, in addition to the regular dots 13a appearing in a line in the horizontal direction of the paper, at positions parallel to the regular dots 13a. It appears irregularly as an abnormal dot 13b. This phenomenon that the abnormal dots 13b are imaged hardly occurs when the width of the LED array is large and the distance between the light emitting portion and the bonding wire is long as in the conventional LED array. Becomes smaller as the distance between the light emitting portion and the bonding wire becomes shorter. An optical printer head in which such an abnormal dot 13b is imaged,
This significantly deteriorates the image quality of the printer, which is a problem.

The present invention has been made to solve the above-mentioned problems of the prior art, and it is possible to suppress the formation of abnormal dots which occur when the width of the light emitting element array is small, thereby improving the image quality. An object of the present invention is to provide an optical printer head capable of outputting and a manufacturing method thereof.

[0018]

According to the first aspect of the present invention,
A plurality of first conductivity type semiconductor blocks separated from each other, a plurality of second conductivity type semiconductor regions formed in each first conductivity type semiconductor block, and a predetermined second conductivity type formed in each first conductivity type semiconductor block A matrix wiring connecting between the mold semiconductor regions, a light emitting element array having a second conductive side pad electrode connected to the matrix wiring, wherein the second conductive side pad electrode is formed in multiple layers on the matrix wiring; An optical printer head comprising: a drive circuit for individually driving the second conductivity type semiconductor region; and a bonding wire for electrically connecting the second conductivity side pad electrode to the drive circuit. It is characterized in that, among the components of light emitted from the mold semiconductor region, a component of light having an emission angle within 60 degrees is not incident on the bonding wire.

According to a second aspect of the present invention, in the first aspect, the second conductive side pad electrode and the driving circuit are connected by a wedge bonding method.

According to a third aspect of the present invention, in the first aspect, the second conductive side pad electrode and the drive circuit are connected by a ball bonding method in which the second conductive side pad electrode is on the second bonding side. It is characterized by having.

According to a fourth aspect of the present invention, there are provided a plurality of first conductivity type semiconductor blocks separated from each other, a plurality of second conductivity type semiconductor regions formed in each first conductivity type semiconductor block, and each first conductivity type semiconductor block. A matrix wiring connecting between predetermined second conductivity type semiconductor regions formed in the semiconductor block; and a second conductive pad electrode connected to the matrix wiring, wherein the second conductive pad electrode is provided on the matrix wiring. A light emitting element array formed in multiple layers, a driving circuit for individually driving the second conductive type semiconductor region, and a bonding wire for electrically connecting the second conductive side pad electrode to the driving circuit. In the optical printer head, a light component having a radiation angle within 60 degrees among light components emitted from the second conductivity type semiconductor region is incident on the bonding wire. Light reflectance of the surface, characterized in that the lower than other portions of the bonding wire.

A fifth aspect of the present invention is characterized in that, in the fourth aspect of the present invention, a material having a lower light reflectance than the surface of the bonding wire is applied.

According to a sixth aspect of the present invention, in the fourth aspect, the bonding wire is covered with a coating material having a lower light reflectance than the surface of the bonding wire.

According to a seventh aspect of the present invention, there are provided a plurality of first conductivity type semiconductor blocks separated from each other, a plurality of second conductivity type semiconductor regions formed in each first conductivity type semiconductor block, and each first conductivity type semiconductor block. A matrix wiring connecting between predetermined second conductivity type semiconductor regions formed in the semiconductor block; and a second conductive pad electrode connected to the matrix wiring, wherein the second conductive pad electrode is provided on the matrix wiring. A light emitting element array formed in multiple layers, a driving circuit for individually driving the second conductive type semiconductor region, and a bonding wire for electrically connecting the second conductive side pad electrode to the driving circuit. A step of connecting the second conductive side pad electrode and the drive circuit by a wedge bonding method, wherein the second conductive side pad electrode is connected to the drive circuit by a wedge bonding method. Among the components of the light emitted from the semiconductor region, components of light within 60 degrees radiation angle is characterized by a structure that does not incident on the bonding wire.

According to the present invention, there are provided a plurality of first conductivity type semiconductor blocks separated from each other, a plurality of second conductivity type semiconductor regions formed in each first conductivity type semiconductor block, and a plurality of first conductivity type semiconductor blocks. A matrix wiring connecting between predetermined second conductivity type semiconductor regions formed in the semiconductor block; and a second conductive pad electrode connected to the matrix wiring, wherein the second conductive pad electrode is provided on the matrix wiring. A light emitting element array formed in multiple layers, a driving circuit for individually driving the second conductive type semiconductor region, and a bonding wire for electrically connecting the second conductive side pad electrode to the driving circuit. A method of manufacturing an optical printer head comprising: a ball bond in which the second conductive side pad electrode and the drive circuit are connected to the second conductive side pad electrode on the second bonding side. A step of performing connection by a bonding method, wherein, among the components of light emitted from the second conductivity type semiconductor region, a component of light having an emission angle within 60 degrees is not incident on the bonding wire. I do.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of an optical printer head and a method of manufacturing the same according to the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of an optical printer head according to the present invention. FIG. 1 (a)
7 shows an optical printer head using an LED array similar to the LED array 1 in FIG. 7A except for a wire bonding portion as a light emitting element array. In addition, LED
As described above, the array 1 is a matrix-type LED array in which the first conductivity type is n-type and the second conductivity type is p-type. The p-type pad electrode 5 is electrically connected to a driving IC (not shown) by a bonding wire 104a, and the n-type pad electrode 15 is electrically connected to a scanning pattern (not shown) by a bonding wire 104b. Here, in the step of electrically connecting the p-type pad electrode 5 and the driving IC with the bonding wire 104a, a wedge bonding method may be used, or a ball in which the p-type pad electrode 5 is on the second bonding side may be used. A bonding method may be used. In the case of the wedge bonding method, the p-type pad electrode 5 may be on either the first bonding side or the second bonding side. Similarly, in the step of electrically connecting the n-type pad electrode 15 and the scanning pattern with the bonding wire 104b, a wedge bonding method may be used, or ball bonding in which the n-type pad electrode 15 side is the second bonding side. Method may be used. In the case of the wedge bonding method, the n-type pad electrode 15 is connected to the first bonding side,
Alternatively, any of the second bonding side may be used. Next, FIG. 1B shows the LED array 5 of FIG. 7C as a light emitting element array except for a wire bonding portion.
1 shows an optical printer head using the same LED array as in FIG. Like the LED array 1, the LED array 51 is a matrix-type LED array in which the first conductivity type is n-type and the second conductivity type is p-type. In the optical printer head shown in FIG. 1B, similarly to the optical printer head shown in FIG. 1A, the p-type pad electrode 5 and the driving IC may be connected by a wedge bonding method. ,
Alternatively, the p-type pad electrodes 5 may be connected by a ball bonding method on the second bonding side.
Further, the n-type pad electrode 55 and the scanning pattern may be connected by a wedge bonding method, or may be connected by a ball bonding method in which the n-type pad electrode 55 side is the second bonding side.

FIG. 2 is a diagram showing a difference in the shape of a bonding portion between two types of wire bonding methods, a ball bonding method and a wedge bonding method. In the case of the ball bonding method, on the first bonding side,
As shown in FIG. 2A, a bonding portion such as a crushed ball is formed, and the bonding wire 2a rises almost perpendicularly to the bonding stage 200. On the other hand, on the second bonding side, a fan-shaped bonding portion formed by crushing the bonding wire 2b is formed, as shown in FIG. 2B, and the bonding wire 2b rises obliquely with respect to the bonding stage 200. In the case of the wedge bonding method, the first
FIG. 2 shows the bonding side and the second bonding side.
As shown in (b), a fan-shaped bonding portion formed by crushing the bonding wire 2b is formed, similar to the second bonding side of the ball bonding method, and the bonding wire rises obliquely to the bonding portion. Therefore, the optical printer head according to the present invention has the structure shown in FIG.
Compared with the conventional optical printer head shown in (a) and (b), the height of the bonding portion can be reduced, and the bonding wire 104a or 104b can be kept away from the light emitting portion 13.

FIG. 3 is a sectional view of the optical printer head according to the present invention, showing the relationship between the bonding wires and the light emitted from the light emitting portion of the LED array.
00 is an LED array, 310 is a light emitting unit, 320 is an axis passing through the light emitting unit 310 and standing perpendicular to the surface of the LED array 300, and 330 is a component of the emitted light emitted from the light emitting unit 310 whose emission angle is 60 degrees. A component 340 of the emitted light indicates a bonding wire when bonding is performed as a second bonding side of a wedge bonding method or a ball bonding method. Further, reference numeral 350 shown by a dotted line
4 shows a bonding wire of the optical printer head shown in FIG. 4 bonded as a first bonding side of the ball bonding method. Here, FIG. 4 is a cross-sectional view of a conventional optical printer head, and reference numeral 360 indicates a bonding wire when bonding is performed as a first bonding side of a ball bonding method. As described above, the component 330 of the emitted light emitted from the light emitting unit 310 is incident on the bonding wire 360 and is reflected on the surface of the bonding wire 360, and an abnormal dot is imaged.

As shown in FIG. 3, the component 330 of the emitted light that enters the bonding wire 350 does not enter the bonding wire 340 due to the difference in the shape of the bonding portion. Therefore, when the optical printer head according to the present invention shown in FIG. 1 is used, the occurrence of abnormal dot image formation can be suppressed as compared with the case where the conventional optical printer head shown in FIG. 12 is used.

According to the above-described embodiment, the plurality of first conductive type semiconductor blocks 11, which are element-isolated from each other,
A plurality of second conductive type semiconductor regions 13 formed in each first conductive type semiconductor block 11, and matrix wiring connecting predetermined second conductive type semiconductor regions 13 formed in each first conductive type semiconductor block 11. 14, the matrix wiring 1
4, a second conductive side pad electrode 5 connected to the second
A light emitting element array 1 in which conductive side pad electrodes 5 are formed in multiple layers on the matrix wiring 14; a drive circuit for individually driving the second conductive type semiconductor regions 13; In an optical printer head having a bonding wire 104a for electrically connecting a drive circuit, of the light components emitted from the second conductive type semiconductor region 13, the light components having a radiation angle within 60 degrees are included. By adopting a structure that does not enter the bonding wire 104a, the width of the light emitting element array 1 is small,
Second conductivity type semiconductor region 13 and bonding wire 104
Even in an optical printer head having a short distance a, the formation of abnormal dots can be suppressed, so that a small optical printer head that outputs good image quality can be provided.

Here, by connecting the second conductive side pad electrode 5 and the drive circuit by the wedge bonding method, the emission angle of the light component emitted from the second conductive type semiconductor region 13 is 60 degrees. It is possible to adopt a structure in which the light component within the above does not enter the bonding wire 104a.

The second conductive side pad electrode 5 and the drive circuit are connected by a ball bonding method in which the second conductive side pad electrode 5 is on the second bonding side, so that the second conductive type semiconductor region 13 is formed. It is also possible to adopt a structure in which, of the light components emitted from the light emitting device, the light components having a radiation angle within 60 degrees do not enter the bonding wire 104a.

Next, another embodiment of the optical printer head according to the present invention will be described. FIG. 5 is a sectional view of the optical printer head of the present embodiment. FIG. 5 (a),
The configuration of the optical printer head according to the present invention shown in FIG. 12B is almost the same as that of the conventional optical printer head shown in FIGS. 12A and 12B, but is abnormal due to light emitted on the surface of the bonding wire. To suppress dot image formation,
The difference is that a substance having a lower light reflectance than the surface of the bonding wire is applied to the vicinity of the bonding portion. A method for manufacturing the optical printer head according to the present embodiment will be described below based on the optical printer head shown in FIG. P-type pad electrode 5 on LED array 1
And a driving IC (not shown) by bonding wire 204
After connection by a, the colored resin 500 is dropped onto the bonding portion on the p-type pad electrode 5 at the tip of the bonding wire 204a, and then the resin 500 is solidified. The light reflectance of the resin 500 is lower than the bonding wire 204.
If the light reflectance is lower than the light reflectance of the surface of the bonding wire 204a, the light reflectance of the bonding portion where the resin 500 is solidified can be lower than that of the surface of the bonding wire 204a. Similarly, L
Also for the bonding wires 204b connecting the n-type pad electrode 15 on the ED array 1 and a scanning pattern (not shown), reflection of emitted light can be suppressed by applying the resin 500 to the bonding portion. As described above, even if the emitted light emitted from the light emitting unit 13 enters the bonding wires 204a and 204b where the resin 500 is applied, the reflection of the emitted light can be suppressed. Therefore, the resin 500 is applied to the bonding wires 204a and 204b where the light components having a radiation angle of 60 degrees or less among the components of the emitted light emitted from the light emitting unit 13 are incident, so that the emitted light is reflected. Image formation of abnormal dots can be suppressed.

In the optical printer head shown in FIG. 5B in which the electrodes are arranged only on one side of the light emitting section 13, the resin 500 is similarly attached to the bonding wire near the bonding section.
Is applied, image formation of abnormal dots can be suppressed. The color of the resin 500 to be applied is not particularly limited, such as black, dark brown, and green, and the components for coloring are not particularly limited, such as pigments and paints. If the gloss is matte, the effect of suppressing the imaging of abnormal dots due to the reflection of the emitted light is further enhanced. Furthermore, the substance to be applied is a substance having electrical insulation performance, such as a resin such as a polyimide-based or silicon-based resin, and if the light reflectance is lower than the surfaces of the bonding wires 204a and 204b, other than the resin. It may be something. Here, the optical printer head according to the present embodiment includes bonding wires 204a, 204a in the manufacturing process of the conventional optical printer head.
Since it can be manufactured only by adding a step of applying a resin to 04b, it can be easily manufactured.

According to the above-described embodiment, the plurality of first conductive type semiconductor blocks 11, which are element-isolated from each other,
A plurality of second conductive type semiconductor regions 13 formed in each first conductive type semiconductor block 11, and matrix wiring connecting predetermined second conductive type semiconductor regions 13 formed in each first conductive type semiconductor block 11. 14, the matrix wiring 1
4, a second conductive side pad electrode 5 connected to the second
A light emitting element array 1 in which conductive side pad electrodes 5 are formed in multiple layers on the matrix wiring 14; a drive circuit for individually driving the second conductive type semiconductor regions 13; In an optical printer head having a bonding wire 204a for electrically connecting a drive circuit, of the light components emitted from the second conductivity type semiconductor region 13, the light components having a radiation angle of 60 degrees or less are included. Since the light reflectance of the surface of the bonding wire 204a to be incident is lower than that of the other part of the bonding wire 204a, even if a light component having a radiation angle of 60 degrees or less is incident on the bonding wire 204a, the wire is not affected. Since reflection of light can be suppressed regardless of the bonding method, imaging of abnormal dots can be suppressed,
A small optical printer head that outputs good image quality can be provided.

Next, still another embodiment of the optical printer head according to the present invention will be described. FIG. 6 is a sectional view of the optical printer head of the present embodiment. FIG.
The configuration of the optical printer head shown in FIGS.
2 (a) and 2 (b), but in order to suppress the formation of abnormal dots due to the emitted light incident on the surface of the bonding wire, the bonding wire is moved to the surface of the bonding wire. It is different in that it is covered with a coating material having a lower light reflectance than that of the coating material. FIG. 6 (a)
A method for manufacturing the optical printer head according to the present embodiment based on the optical printer head shown in FIG. After connecting the p-type pad electrode 5 on the LED array 1 and the drive IC (not shown) with the bonding wire 204a, the surface of the bonding wire 204a is covered with a colored coating material 600. If the light reflectance of the coating material 600 is lower than the light reflectance of the surface of the bonding wire 204a,
The surface of the bonding wire 204a covered with the covering material 600 can have a lower light reflectance than the surface of the bonding wire 204a not covered with the covering material 600. Similarly, the n-type pad electrode 15 on the LED array 1
Also, by covering the bonding wire 204b connecting the scanning pattern (not shown) with the covering material 600, the reflection of the emitted light can be suppressed. As described above, even if the emitted light emitted from the light emitting unit 13 enters the bonding wires 204a and 204b covered with the covering material 600, the reflection of the emitted light can be suppressed. Therefore,
By covering the portions of the bonding wires 204a and 204b, into which the light component having a radiation angle of 60 degrees or less among the components of the emitted light emitted from the light emitting unit 13 is incident, with the coating material 600, abnormal dots due to the reflection of the emitted light are obtained. Can be suppressed.

In the optical printer head shown in FIG. 6B in which the electrodes are arranged only on one side of the light emitting section 13, the bonding wires 204 a and 204 b are similarly covered with the covering material 600.
, The formation of abnormal dots can be suppressed. The color of the coating material 600 may be black, dark brown, green, or the like, and is not particularly limited. The coating material 600 has a light reflectance of the bonding wire 204.
What is necessary is just to be lower than the surface of a, 204b. Here, the optical printer head according to the present embodiment includes a bonding wire 2 in a manufacturing process of a conventional optical printer head.
Since it can be manufactured only by adding a step of covering the layers 04a and 204b with the coating material 600, it can be easily manufactured.

Next, still another embodiment according to the present invention will be described. The present embodiment is the same as the optical printer head shown in FIG. 6 in that imaging of abnormal dots due to reflection of emitted light incident on the bonding wire is suppressed by covering the bonding wire with a covering material. The difference is that a bonding wire previously covered with a covering material is used. That is, in the present embodiment, the bonding wire is already covered with the covering material before the wire bonding, and the covering wire is not covered with the covering material after the wire bonding. Here, the optical printer head according to the present embodiment can be manufactured easily by simply changing the bonding apparatus to a bonding apparatus for a bonding wire with a coating material without changing the conventional manufacturing process. can do.

[0039]

According to the first, second, and third aspects of the present invention,
A plurality of first conductivity type semiconductor blocks separated from each other, a plurality of second conductivity type semiconductor regions formed in each first conductivity type semiconductor block, and a predetermined second conductivity type formed in each first conductivity type semiconductor block A matrix wiring connecting between the mold semiconductor regions, a light emitting element array having a second conductive side pad electrode connected to the matrix wiring, wherein the second conductive side pad electrode is formed in multiple layers on the matrix wiring; An optical printer head comprising: a drive circuit for individually driving the second conductivity type semiconductor region; and a bonding wire for electrically connecting the second conductivity side pad electrode to the drive circuit. The light emitting element having a radiation angle of 60 degrees or less among the light components emitted from the mold semiconductor region is configured not to be incident on the bonding wire. A small optical printer that outputs good image quality because it can suppress the formation of abnormal dots even in an optical printer head having a small width size and a short distance between the second conductivity type semiconductor region and the bonding wire. A head can be provided.

According to the present invention, a plurality of first conductivity type semiconductor blocks separated from each other, a plurality of second conductivity type semiconductor regions formed in each first conductivity type semiconductor block, A matrix wiring connecting between predetermined second conductivity type semiconductor regions formed in the first conductivity type semiconductor block; a second conductive side pad electrode connected to the matrix wiring; A light emitting element array formed in multiple layers on the matrix wiring, a driving circuit for individually driving the second conductivity type semiconductor region,
In an optical printer head having the second conductive side pad electrode and a bonding wire for electrically connecting the driving circuit, the light component emitted from the second conductive type semiconductor region has a radiation angle of 60%. The light reflectance of the surface of the bonding wire on which the light component within a degree is incident is lower than other portions of the bonding wire,
Even if a light component having a radiation angle of 60 degrees or less is incident on the bonding wire, the reflection of light can be suppressed regardless of the method of wire bonding. It is possible to provide a small optical printer head that outputs high image quality.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of an optical printer head according to the present invention.

FIG. 2 is a diagram showing an example of a difference in the shape of a bonding portion between two types of wire bonding methods, a ball bonding method and a wedge bonding method.

FIG. 3 is a sectional view showing an embodiment of the optical printer head according to the present invention.

FIG. 4 is a sectional view showing an example of a conventional optical printer head.

FIG. 5 is a cross-sectional view showing another embodiment of the optical printer head according to the present invention.

FIG. 6 is a sectional view showing still another embodiment of the optical printer head according to the present invention.

FIG. 7 is a diagram showing an example of the structure of a light emitting element array used in the optical printer head according to the present invention.

FIG. 8 is a sectional view showing an example of the structure of a conventional optical printer head.

FIG. 9 is a schematic view showing an example of a conventional wire bonding.

FIG. 10 is a schematic explanatory view showing an example of a wire bonding step by a ball bonding method.

FIG. 11 is a schematic explanatory view showing an example of a state of light emitted from a light emitting unit on an LED array element.

FIG. 12 is a sectional view showing an example of a conventional optical printer head.

FIG. 13 is an explanatory diagram showing an example of an image forming state of a conventional optical printer head.

[Explanation of symbols]

Reference Signs List 1,51 LED array 2 High-resistance semiconductor substrate 4 Common matrix wiring 5 P-type pad electrode 6 P-type pad wiring 11 N-type semiconductor block 12a, 12b, 12c Interlayer insulating film 13 P-type semiconductor region (light emitting unit) 14 Individual matrix wiring 15 n-type pad electrode 52 n-type contact electrode 55 n-type pad electrode 104a, 104b bonding wire 202 drive IC 203 scanning pattern 204a, 204b bonding wire 500 resin 600 coating material

Claims (8)

[Claims] 1. A plurality of first conductivity type semiconductor blocks separated from each other, a plurality of second conductivity type semiconductor regions formed in each first conductivity type semiconductor block, and a plurality of first conductivity type semiconductor blocks formed in each first conductivity type semiconductor block. A matrix wiring connecting between predetermined second conductivity type semiconductor regions; a second conductive pad electrode connected to the matrix wiring; and the second conductive pad electrode is formed in multiple layers on the matrix wiring An optical printer head comprising: a light emitting element array; a drive circuit for individually driving the second conductivity type semiconductor region; and a bonding wire for electrically connecting the second conductivity side pad electrode and the drive circuit. In the structure, the component of the light emitted from the second conductivity type semiconductor region and having a radiation angle within 60 degrees is not incident on the bonding wire. And an optical printer head. 2. The drive circuit according to claim 1, wherein the second conductive side pad electrode is connected to the drive circuit by a wedge bonding method.
The optical printer head as described. 3. The optical printer head according to claim 1, wherein the second conductive side pad electrode and the drive circuit are connected by a ball bonding method in which the second conductive side pad electrode is on the second bonding side. 4. A plurality of first conductivity type semiconductor blocks separated from each other, a plurality of second conductivity type semiconductor regions formed in each first conductivity type semiconductor block, and a plurality of first conductivity type semiconductor blocks formed in each first conductivity type semiconductor block. A matrix wiring connecting between predetermined second conductivity type semiconductor regions; a second conductive pad electrode connected to the matrix wiring; and the second conductive pad electrode is formed in multiple layers on the matrix wiring An optical printer head comprising: a light emitting element array; a drive circuit for individually driving the second conductivity type semiconductor region; and a bonding wire for electrically connecting the second conductivity side pad electrode and the drive circuit. Of the light components emitted from the second conductivity type semiconductor region, the light reflectance of the surface of the bonding wire on which the light component having a radiation angle within 60 degrees is incident is higher. An optical printer head which is lower than other portions of the bonding wire. 5. The optical printer head according to claim 4, wherein a substance having a lower light reflectance than the surface of the bonding wire is applied. 6. The optical printer head according to claim 4, wherein the optical printer head is covered with a coating material having a lower light reflectance than the surface of the bonding wire. 7. A plurality of first conductivity type semiconductor blocks separated from each other, a plurality of second conductivity type semiconductor regions formed in each first conductivity type semiconductor block, and a plurality of first conductivity type semiconductor blocks formed in each first conductivity type semiconductor block. A matrix wiring connecting between predetermined second conductivity type semiconductor regions; a second conductive pad electrode connected to the matrix wiring; and the second conductive pad electrode is formed in multiple layers on the matrix wiring An optical printer head comprising: a light emitting element array; a drive circuit for individually driving the second conductive semiconductor region; and a bonding wire for electrically connecting the second conductive pad electrode and the drive circuit. A method of connecting the second conductive side pad electrode and the drive circuit by a wedge bonding method, wherein the second conductive side pad electrode is connected to the second conductive type semiconductor region. Among the components of the light, manufacturing method of an optical printer head component of light within 60 degrees radiation angle is characterized by a structure that does not incident on the bonding wire. 8. A plurality of first conductivity type semiconductor blocks separated from each other, a plurality of second conductivity type semiconductor regions formed in each first conductivity type semiconductor block, and a plurality of first conductivity type semiconductor blocks formed in each first conductivity type semiconductor block. A matrix wiring connecting between predetermined second conductivity type semiconductor regions; a second conductive pad electrode connected to the matrix wiring; and the second conductive pad electrode is formed in multiple layers on the matrix wiring An optical printer head comprising: a light emitting element array; a drive circuit for individually driving the second conductive semiconductor region; and a bonding wire for electrically connecting the second conductive pad electrode and the drive circuit. A manufacturing method, wherein the second conductive-side pad electrode and the drive circuit are connected to the second conductive-side pad electrode.
Performing a step of connecting by a ball bonding method in which the conductive side pad electrode is on the second bonding side, and among the light components emitted from the second conductive type semiconductor region, the light component having a radiation angle within 60 degrees is A method for manufacturing an optical printer head, wherein the optical printer head does not enter a bonding wire.