JP2000114604A - Light emitting element array and manufacture of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To highly precisely set a light emission interval, and to realize high luminance. SOLUTION: An LED array 10 is provided with a substrate 12 and LED chips 14, and the substrate 12 is provided with a plurality of hole parts 18 for housing each LED chip 14. The emission interval of lights emitted from each LED chip 14 is decided according to an interval between each hole part 18 so that it is not necessary to hold the bonding precision of the LED chips 14 high.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting element array having a plurality of light emitting elements arranged on a substrate and a method of manufacturing the same.

[0002]

2. Description of the Related Art Generally, a plurality of light emitting elements such as SLDs or LEDs (hereinafter simply referred to as LEDs) are arranged in a linear and / or matrix form as light sources for an image reading scanner or an image output (recording) printer. An array of light emitting elements is used.

In this type of LED type light emitting element array, L
Variations in ED light intensity and array spacing directly
This leads to streaks and uneven density, which causes a decrease in print quality. For this reason, in order to improve print quality,
It is necessary to arrange a plurality of LED chips having a uniform light amount on a substrate at equal intervals with high precision. At that time, the order of the arrangement accuracy is required to be on the order of micrometers, and if this arrangement accuracy can be reduced to the order of several micrometers or less,
The printer itself can be reduced in cost and stabilized. Further, in order to shorten the printing time and to increase the printing speed, it is desirable that the brightness be high.

Therefore, conventionally, in a semiconductor manufacturing process, a method has been known in which light emitting elements are directly formed on a silicon substrate at regular intervals (see, for example, Japanese Patent Application Laid-Open No. 9-4).
5958 and JP-A-6-31075). However, in the above conventional method, each LED
There is a problem that the variation in light emission intensity of the chips becomes large and it becomes difficult to correct the light amount, and the yield decreases as the number of the LED chips increases. Furthermore, in the monolithic LED array, of the light emitted on the entire surface of the PN junction, only the light directed toward the front surface can be used effectively, so that it is difficult to obtain high intensity and the energy efficiency is poor.

On the other hand, a method of bonding LED chips one by one on a printed circuit board at regular intervals is disclosed in, for example, Japanese Patent Application Laid-Open Nos. 5-21849 and 8-156320. In these techniques, for example, as shown in FIG. 20, a plurality of LED chips 3 are arranged on a substrate 2 at regular intervals in a certain direction, so that L
The ED array 4 is configured.

[0006]

SUMMARY OF THE INVENTION However, LEDs
The outside diameter accuracy of the chip 3 is poor, and the outside diameter shape of the LED chip 3 and the light emission center are often shifted. Accordingly, in the LED array 4 described above, in order to maintain the interval between the light emission centers of the LED chips 3 with high accuracy, it is necessary to recognize the light emission center by a complicated and expensive optical process. The problem of being an economy has been pointed out. In addition, there is a problem that the accuracy of this type of optical processing is poor.

Further, the LED chip 3 has a side of 0.2
Some are considerably small, such as 5 mm to 0.4 mm, and it is extremely difficult to bond this type of LED chip 3 to the substrate 2 with high accuracy and stability.
Furthermore, as shown in FIG.
The light derived from the N-junction 5 is output in all directions, up and down, and in the horizontal direction, but has the property of having the highest intensity in the horizontal direction in FIG. As a result, a problem has been pointed out that the light emitted from the LED chip 3 cannot be used effectively.

The present invention solves this kind of problem, and provides a light emitting element array capable of maintaining a light emitting interval of each light emitting element with high precision and having a high luminance and a uniform light amount, and a method of manufacturing the same. The purpose is to provide.

[0009]

In the light emitting element array and the method of manufacturing the same according to the present invention, a plurality of holes are provided in a substrate, and one light emitting element is accommodated in each hole.
Thus, since the light emitting interval between the light emitting elements is determined by the accuracy of the interval between the holes, it is not necessary to bond each light emitting element with high accuracy, and the light emitting interval accuracy can be maintained satisfactorily.

[0010] Here, the hole has a substantially parabolic surface surrounding the light emitting element, and light derived from the light emitting element is reflected by the substantially parabolic surface to be surely emitted from the hole to the outside. Is irradiated. Therefore, light generated from the light emitting element can be used effectively. In particular, high-brightness and high-intensity light can be obtained by performing mirror processing on a substantially parabolic surface.

In addition, since the light emitting element is arranged substantially corresponding to the focal position of the paraboloid, the effective use of the light generated from the light emitting element is more reliably performed. Further, since the drive current supply wiring is provided from the front surface or the hole of the substrate toward the back surface of the substrate, the wiring on the front surface of the substrate can be made unnecessary. Becomes possible.

Further, the substrate is divided into a plate member in which a hole is formed and a bottom plate on which the light emitting element is mounted, and the plate member and the bottom plate are integrally fixed. Thereby, in addition to the procedure for mounting the light emitting element after fixing the plate material to the bottom plate, the procedure for mounting the light emitting element on the bottom plate in advance and then fixing the plate material can be performed, and the workability can be easily improved. It is planned.

[0013]

FIG. 1 is a schematic perspective explanatory view of an LED array 10 which is a light emitting element array according to a first embodiment of the present invention. The LED array 10 includes a substrate 12 and a plurality of LEs arranged at equal intervals on the substrate 12.
And a D chip (light emitting element) 14.

The substrate 12 is made of a material such as a silicon wafer or glass, in addition to a metal such as copper or aluminum, and has a predetermined depth and is equally spaced from each other on the surface 16 of the substrate 12. A plurality of holes 18 are provided. Each hole 18 has a bottom surface 20 on which the LED chip 14 is arranged, and a substantially parabolic surface 22 around the LED chip 14.
And the substantially parabolic surface 22 has a mirror surface processing unit 2
4 are provided. This mirror surface processing unit 24 has a substantially parabolic surface 22.
Is formed by depositing or plating a metal such as silver, aluminum or chromium. The LED chip 14 has a bottom surface 2 corresponding to the focal position of the substantially parabolic surface 22.
0 (see FIG. 2).

A micro lens 28 is arranged on the substrate 12 corresponding to the opening 26 of the hole 18. The microlenses 28 are individually attached to the surface 1 of the substrate 12 with an adhesive.
6, the microlens array 30 in which the plurality of microlenses 28 are integrally formed is fixed to the surface 16 with an adhesive or the like.

As shown in FIG. 2, a through hole 32 is formed in the bottom surface 20 of each hole 18 and a lead (wiring for supplying a drive current) 36 is formed in the through hole 32 via an insulating material 34. You. One end of the lead 36 and the LED chip 14 are bonded by a wire 38, while the other end of the lead 36 is led out to the back side of the substrate 12 and wired.

FIG. 3 is a schematic diagram illustrating the configuration of a printing apparatus 40 incorporating the LED array 10. Printing device 4
Reference numeral 0 denotes an exposure section 42 for exposing and recording an image on the photosensitive material F wound in a roll, a developing section 44 for performing a developing process on the exposed photosensitive material F, and a developing section 44 after the development.
And an accumulating unit 46 for accumulating.

The exposure section 42 has a transport system 48 for feeding out the photosensitive material F and transporting the photosensitive material F in the horizontal direction (the direction of arrow A), and a pair of nip rollers 50 constituting the transport system 48.
LED exposure heads 52, 54 and 56 are arranged between them. The LED exposure heads 52, 54 and 56 are set corresponding to the three primary colors of R, G and B, respectively, for exposing and recording a color image on the photosensitive material F.

As shown in FIG. 4, the LED exposure head 5
Each of 2, 54 and 56 includes an LED array 10 and a selfoc lens array 58, and is configured to collect light on the photosensitive material F. An image processing device 60 and an image input device 62 are connected to the printing device 40, and a predetermined image is recorded and reproduced on the photosensitive material F.

FIG. 5 is a block diagram showing the L according to the first embodiment of the present invention.
FIG. 2 is a schematic configuration explanatory view of a scanner device 70 in which the ED array 10 is incorporated. The scanner device 70 includes a glass table 74 on which a document 72 for reading is placed, and a scanning table 76 movable in the direction of arrow B is disposed below the glass table 74.

On the scanning table 76, LED arrays 10 _R , 10 _G and 10 _B are arranged at different inclination angles, and each LED array 1
0 _R , 10 _G and 10 _B illuminate the original 72
And is introduced into the light receiving element array 78. LED
Arrays 10 _R , 10 _G and 10 _B represent R,
The colors are set corresponding to the three primary colors G and B. A light receiving signal processing device 80 is connected to the light receiving element array 78, and an image information storage device 82 is connected to the light receiving signal processing device 80.

A method of manufacturing the LED array 10 having the above-described structure will be described below.

First, as shown in FIG. 6, a substrate material 12a constituting the substrate 12 is prepared. This substrate material 12a
A plurality of holes 18 are equally spaced from each other on the surface 16a of the
Is formed to a predetermined depth by etching or machining (see FIG. 7). Next, a metal such as silver, aluminum, or chromium is coated on the substantially parabolic surface 22 constituting the hole portion 18 to form a mirror-finished portion 24 (see FIG. 8).

Further, as shown in FIG. 9, the LED chip 14 has a substantially parabolic surface 22 on the bottom surface 20 forming the hole 18.
Is mounted corresponding to the focal position of Here, a silver paste and a conductive adhesive are provided on the bottom surface 20 of the hole 18 in advance, and the LED chip 14 is fixed to the bottom surface 20. Then, as shown in FIG. 10, a microlens array 30 integrally formed with a plurality of microlenses 28 is fixed to the surface 16 of the substrate 12, and the LED array 10 is manufactured.

When wiring is performed on the back surface side of the substrate 12, as shown in FIG. 2, a lead 36 is previously mounted in the through hole 32 via an insulating material 34, and the LED chip 14
When the LED chip 14 is fixed to the bottom surface 20, the lead 36 is bonded to the LED chip 14 via a wire 38.

In the LED array 10 configured as described above, as shown in FIG. 11, the light generated at the PN junction surface 14a of the LED chip 14 is reflected by the mirror surface treatment provided on the substantially parabolic surface 22 of the hole 18. Reflected by the part 24,
Almost all light is emitted to the outside from the opening 26 of the hole 18. For this reason, the light generated from the LED chip 14 can be used effectively, and the high-brightness and high-intensity light is
The effect that irradiation from the ED array 10 becomes possible is obtained.

Therefore, in the printing apparatus 40, the exposure unit 4
LED on photosensitive material F fed out in the direction of arrow A at 2
By irradiating light from the exposure heads 52, 54 and 56, a desired color image can be formed on the photosensitive material F with high quality and quickly.

On the other hand, in the scanner device 70, the original 72 is moved from the LED arrays 10 _R , 10 _G and 10 _B through the scanning table 76 in the direction of arrow B.
By irradiating the original 72 with desired light, the color image information held by the original 72 can be reliably introduced into the light receiving element array 78. As a result, the color image held by the document 72 via the light reception signal processing device 80 can be stored in the image information storage device 82 with high quality and accuracy.

Further, in the first embodiment, as shown in FIG. 12, even if the center of the LED chip 14 is shifted from the center of the hole 18 by the distance H, the light generated from the LED chip 14 is subjected to mirror finishing. The light is reflected by the portion 24 and can be reliably led to the outside. That is, each LED chip 1
4 is determined by the accuracy of the spacing between the holes 18, and the LE at the bottom surface 20.
There is no need to set the bonding position of the D chip 14 with high accuracy. For this reason, the bonding operation of the LED chip 14 is simplified, and in particular, the LED chip 14 having a small size is used.
The effect of simplifying the bonding operation at once can be obtained.

As described above, in the first embodiment, the LED
High precision bonding of the chip 14 is not required, and with a simple operation and configuration, it is possible to obtain the LED array 10 having excellent light emitting interval accuracy, and to surely generate high brightness and high intensity light. Become. Moreover,
An LED chip 14 having a uniform luminance can be used in advance by performance inspection, and by manufacturing the LED array 10 having a uniform light amount, the light amount assurance control device and the like become unnecessary, and the entire printing device 40 and scanner device 70 are inexpensive. Further, there is obtained an advantage that it is possible to reduce the size.

Further, as shown in FIG.
Since the zero surface wiring is not required, it can be adopted in the contact exposure method. At this time, each micro lens 28
Prevents the sheet from being in close contact with the LED array 10 and allows the LED array 10 to run smoothly. Furthermore, for example, a long LED exposure head 5 for A3 size
It can be easily applied to 2, 54, 56 and the like.

The microlens 28 may be used as needed, and the microlens 28 can be made unnecessary by designing an optical system on the apparatus side. Here, when the microlens array 30 is fixed to the substrate 12, if the microlens array 30 is bonded in a nitrogen-substituted atmosphere, the LED chip 14 may be exposed to moisture or the like.
Can be prevented from deteriorating. In addition, although the mirror surface processing unit 24 is provided on the substantially parabolic surface 22, it may be configured as a curved surface or a flat surface close to the parabolic surface depending on the use.

FIG. 13 is a schematic explanatory view of an LED array 90 according to the second embodiment of the present invention. The same components as those of the LED array 10 according to the first embodiment are denoted by the same reference numerals, and a detailed description thereof will be omitted.

The LED array 90 has a substrate 92, and the substrate 92 is provided on the plate 9 on which the hole 18 is formed.
4 and a bottom plate 96 on which the LED chip 14 is mounted. The plate member 94 and the bottom plate 96 are integrally fixed by an adhesive or a screw.

The operation of manufacturing the LED array 90 thus configured will be described below.

First, as shown in FIG.
a is prepared. Like the bottom plate 96, the plate material 94a is made of a metal such as copper or aluminum, or a material such as a silicon wafer or glass. Board material 94a
Are provided with through holes 9 at regular intervals and corresponding to the holes 18.
8 are formed (see FIG. 15), and the plate material 94 in which the through holes 98 are formed is fixed on the bottom plate 96 by an adhesive, a screw, or the like (see FIG. 16). Thus, the hole 18 is formed between the plate member 94 and the bottom plate 96, and the substrate 92 is formed.

Next, as shown in FIG. 17, after the substantially parabolic surface 22 constituting the hole 18 is coated with a metal such as silver, aluminum or chromium to form the mirror-finished portion 24, the bottom plate 96 LED chip 1 on bottom surface 20
4 is mounted via a silver paste and a conductive adhesive (see FIG. 18). Further, in a nitrogen atmosphere, the microlens array 30 is fixed to the surface of the
The ED array 90 is manufactured (see FIG. 19).

In addition to the procedures shown in FIGS. 14 to 19, the LED chip 14 is bonded to the bottom plate 96 in advance, and a hole is formed in the plate material 94a. The obtained plate 94 is attached to the LE.
The D chip 14 may be fixed on the bottom plate 96 to which the D chip 14 is bonded by using an adhesive or a screw.

As described above, in the second embodiment, the substrate 9
Since 2 is divided into the plate material 94 and the bottom plate 96, the work procedure can be changed as needed, and the effect of improving the degree of freedom of work can be obtained. Besides, LED chip 1
No need to maintain high bonding accuracy of 4
The first is that the production work of the D-array 90 is simplified at once.
The same effect as that of the embodiment can be obtained.

Although the microlenses 28 are used in the first and second embodiments, flat glass or the like may be used instead of the microlenses 28.

In the second embodiment, the plate member 94 is made of an insulating material, or the surface of the bottom plate 96 (corresponding to the bottom surface 20) is insulated, and a wiring is formed on the bonding surface of the bottom plate 96 in advance. A pattern can be formed.
This eliminates the need for a wire bonding operation at a deep position, thereby improving productivity.

[0042]

In the light emitting element array and the method of manufacturing the same according to the present invention, a plurality of holes are provided in the substrate, and one light emitting element is accommodated in each of the holes. For this reason, since the light emission interval is determined according to the interval between the holes, it is not necessary to bond the light emitting elements with high precision, and a light emitting element array with excellent light emission interval accuracy is reliably manufactured in a simple process. can do.

[Brief description of the drawings]

FIG. 1 is a schematic perspective explanatory view of an LED array according to a first embodiment of the present invention.

FIG. 2 is a partially sectional explanatory view of the LED array.

FIG. 3 is a schematic configuration explanatory view of a printing apparatus incorporating the LED array.

FIG. 4 is an explanatory diagram of an LED exposure head incorporated in the printing apparatus.

FIG. 5 is a schematic configuration explanatory view of a scanner device in which the LED array is incorporated.

FIG. 6 is a front view of a substrate material for manufacturing a substrate constituting the LED array.

FIG. 7 is an explanatory view when drilling a hole in the substrate material.

FIG. 8 is an explanatory view when a mirror surface treatment is performed on a substantially parabolic surface obtained by the drilling.

FIG. 9 is an explanatory view when mounting an LED chip on the substrate.

FIG. 10 is an explanatory diagram when a microlens array is fixed to the substrate.

FIG. 11 is an explanatory diagram of a light emitting state of the LED chip in the hole.

FIG. 12 is a diagram illustrating a light emitting state when the center of the LED chip is shifted in the hole.

FIG. 13 is a schematic perspective explanatory view of a light emitting element array according to a second embodiment of the present invention.

FIG. 14 is an explanatory front view of a plate material for manufacturing a plate material, which is one element of a substrate constituting the light emitting element array.

FIG. 15 is an explanatory cross-sectional view when a hole is formed in the plate material.

FIG. 16 is an explanatory view showing a state where the plate material is fixed to a bottom plate which is the other element of the substrate.

FIG. 17 is an explanatory diagram when a mirror surface treatment is performed on a substantially parabolic surface obtained by the drilling.

FIG. 18 is an explanatory diagram when an LED chip is mounted on the bottom plate.

FIG. 19 is an explanatory diagram when the microlens array is fixed on the plate material.

FIG. 20 is an explanatory perspective view of an LED array according to the related art.

FIG. 21 shows an LED constituting the LED array shown in FIG. 20;
It is operation | movement explanatory drawing of a chip | tip.

[Explanation of symbols]

_{10,10 R, 10 G, 10 B} , 90 ... LED array 12,92 ... substrate 14 ... LED chip 16 ... surface 18 ... the hole 20 ... bottom 22 ... substantially paraboloid 24 ... mirror section 26 ... opening 28 ... Microlens 30 ... Microlens array 36 ... Lead 40 ... Printing device 42 ... Exposure unit 52,54,56
... LED exposure head 58 ... Selfoc lens array 60 ... Image processing device 62 ... Image input device 70 ... Scanner device 74 ... Glass table 80 ... Light receiving signal processing device 82 ... Image information storage device 94 ... Plate material 96 ... Bottom plate

Claims (9)

[Claims] 1. A light emitting element array comprising a plurality of light emitting elements arranged on a substrate, wherein the substrate has a plurality of holes for accommodating the light emitting elements one by one. Light emitting element array. 2. The light emitting element array according to claim 1, wherein
The light emitting element array, wherein the hole has: a bottom surface on which the light emitting element is arranged; and a substantially paraboloid surrounding the light emitting element. 3. The light emitting element array according to claim 2, wherein
The light emitting element array, wherein the substantially parabolic surface is subjected to a mirror surface treatment. 4. The light-emitting element array according to claim 2, wherein said light-emitting elements are arranged on said bottom surface corresponding to a focal position of said substantially parabolic surface. 5. The light emitting element array according to claim 1, wherein
A light emitting element array, wherein a drive current supply wiring is provided from the front surface of the substrate or the hole to the rear surface of the substrate. 6. The light emitting device array according to claim 1, wherein
The light emitting device array, comprising: a substrate having the hole formed therein; and a bottom plate on which the light emitting element is mounted, wherein the plate and the bottom plate are integrally fixed. 7. A method of manufacturing a light emitting element array by arranging a plurality of light emitting elements on a substrate, comprising: providing a plurality of holes at a predetermined depth from a surface of the substrate; Mounting the light emitting elements one by one on each bottom surface. 8. A method for manufacturing a light-emitting element array by arranging a plurality of light-emitting elements on a substrate, the method comprising: providing a plurality of holes in a plate material forming the substrate; A step of integrally fixing the plate member, and a step of mounting the light emitting element corresponding to the hole portion on the bottom plate before or after fixing the bottom plate and the plate member. A method for manufacturing a light-emitting element array. 9. The method for manufacturing a light emitting element array according to claim 7, further comprising a step of subjecting the substantially parabolic surface of the hole surrounding the light emitting element to a mirror surface treatment.