JPH10215004A - Photoelectronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the strength against deformation and breakdown of light emitting diode chips and metal fine wires by external pressure and breakdown and peeling of sealing resin by bending and expansion/shrinkage differences of a printed wiring board by specifying the epoxy resin using cationic- polymerization-based curing catalyst for a resin sealing body. SOLUTION: A transparent resin sealing body 24 is made to have approximately a semispherical shape so as to be resistant against the bending of a printed wiring board 21. For this body 24, the epoxy resin using triallyl- sulfonium-hexafluoroantimonate, which is the cationic-polymerization-based curing catalyst, is adopted. Then, light emitting diode chips 22 and metal fine wires 23, which electrically connect the chips, are seeled and cured under the state, wherein the viscous flowing is blocked, on the main surface of the printed wiring board 21. The transparent resin material withstands bending and the expanding and shrinkage of the printed wiring board 21 and is the material having the high thixotropic property, which can seal and cure the substrate in the specified shape under the state, wherein the viscous flowing is blocked. The material contains silica as filling material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optoelectronic device applied to a light emitting device or a light receiving device used in a facsimile, a word processor, an image scanner for reading an image of a copying machine, a display device, and the like.

[0002]

2. Description of the Related Art In recent years, when an image reading light source reads out image information with an image sensor in a facsimile, a word processor, or an image scanner section of a copying machine, etc.
It is used as a light source for irradiating light to a document to be read. In addition, a light emitting diode light source is used as a light source of this type of device.

A light-emitting diode light source will be described below as an example of a conventional image reading light source with reference to FIGS. FIG. 4 is a sectional view of a main part of a contact image scanner unit using the light emitting diode light source. The contact type image scanner unit includes a light emitting diode light source 1, a document 2, a selfoc lens array 4, and an image sensor 5. 3 is an optical axis. In this contact type image scanner unit, light is emitted from a light emitting diode light source 1 along a reading line on a document 2 and reflected light from the document 2 is focused by a selfoc lens array 4 and arranged on the same straight line. It is led to 5.
Image information received by the image sensor 5 and decomposed into minute pixels is extracted as an electric signal for each pixel density.

FIGS. 5 and 6 show a light emitting diode light source 1 used in this contact type image scanner section. FIG.
6 is a perspective view thereof, and FIG. 6 is a sectional view taken along line YY of FIG. The light emitting diode light source 1 is composed of a printed wiring board 10 on which a conductor of a predetermined pattern is formed, a light emitting diode chip 11, a thin metal wire 12, a resin sealing body 13 thereof, and a current limiting resistor 19. A light emitting diode chip 11 is attached to a predetermined portion of a conductor 14 on the printed wiring board 10 to make electrical connection with a thin metal wire 12 and is sealed on the printed wiring board 10 by a transparent resin sealing body 13. The current limiting resistor 19 controls the current supplied to the light emitting diode chip 11 to a predetermined value.
As shown in FIG. 5, the light emitting diode chips 11 are mounted on the printed wiring board 10 so as to correspond to the groups, and are connected to the conductors.

[0005]

The conventional light-emitting diode light source 1 as described above is required to be low-priced in the market, and there is a light-emitting diode light source that is easy to handle with little restriction when assembled into a set. It has been demanded. Therefore, there is a demand for a resin-encapsulating material having good light-transmitting properties so that light from the light-emitting diode chips 11 can be efficiently extracted and the number of light-emitting diode chips 11 can be minimized.

In addition, when the light emitting diode light source 1 is attached to a set, or when the light emitting diode light source 1 is removed from the set due to a mounting failure, the printed wiring board 10 is bent, or the product is transported, and printed wiring due to a temperature change in an operating environment. In general, a flexible silicone resin is used so as to withstand separation or the like due to a difference in expansion / shrinkage rate between the substrate 10 and the resin sealing body 13.

However, since the silicone resin has a low resin hardness, an operator in a manufacturing process of manufacturing the light emitting diode light source 1 presses the resin sealing body 13 or mounts the resin sealing body 13 in a set. There is a drawback that the light emitting diode chip 11 and the thin metal wires 12 are deformed and destroyed by external pressure such as pressing. For this reason, it is necessary to always manage the light emitting diode light source 1 so that no external pressure is applied even in the assembling process, which leads to an increase in the number of assembling steps. Furthermore, the silicone resin has a weak adhesive force with other substances, and the light emitting diode chip 11 and the thin metal wires 12 are broken by peeling from the printed wiring board 10, which causes a problem. Further, the silicone resin has a disadvantage that it is expensive and impractical.

Although the use of an epoxy resin instead of the silicone resin is conceivable, a general acid anhydride or amine epoxy resin has high hardness and lacks flexibility. Failure and delamination of the resin occur, and as a result, the light emitting diode chip 11 and the thin metal wires 12 are broken. In addition, the epoxy resin is generally of a two-liquid type, and its viscosity changes with the passage of time. Therefore, it is necessary to use the epoxy resin in a short period of time. If it becomes difficult to do so, the material must be discarded, so that the material loss increases. Further, the acid anhydride curing agent is mixed with the epoxy resin in an equivalent amount, and a trace of unreacted curing agent remains even when thermally cured. The permeated water reaches the light emitting diode chip 11 while extracting the unreacted curing agent. Since the water containing the unreacted curing agent shows strong acidity, it promotes the corrosion of the P-side electrode of the light emitting diode chip 11 in a high-temperature and high-humidity environment, and the disconnection occurs due to the corrosion destruction of the electrode portion. Resulting in. In addition, the amine-based epoxy resin has a problem in that the resin discolors in a use environment and light from the light emitting diode chip 11 cannot be efficiently extracted.

The present invention solves the above problems,
Resistant to deformation and destruction of light emitting diode chips and thin metal wires due to external pressure, resistant to destruction and peeling of sealing resin due to bending, expansion and contraction differences of printed wiring boards, and also effective in preventing electrode corrosion, assembly An object is to provide an easy and low-cost optoelectronic device.

[0010]

According to a first aspect of the present invention, there is provided an optoelectronic device, comprising: a substrate; an element mounted on and connected to the substrate for receiving or emitting light; and a translucent element in which the element is sealed on the substrate. And a resin sealing body, wherein the resin sealing body is an epoxy resin using a cationic polymerization-based curing catalyst.

According to the optoelectronic device of the first aspect, the light emitting diode chip and the thin metal wire can be prevented from being deformed or destroyed by the external pressure because they are resistant to external pressure, bending, expansion and contraction, and electrode corrosion. The destruction and peeling of the sealing resin due to the difference in the bending and expansion and contraction of the substrate can be prevented, and the reliability against electrode corrosion can be improved. Furthermore, it is possible to provide a product that is easy to assemble and that can respond to cost reduction.

According to a second aspect of the present invention, in the first aspect, the cationic polymerization type curing catalyst is a triarylsulfonium hexafluoroantimonate salt type curing agent. According to the optoelectronic device of the second aspect, in addition to the effect of the first aspect, it is possible to use one liquid of the epoxy resin, thereby shortening the assembling process, reducing the number of steps, and further reducing the cost.

According to a third aspect of the present invention, there is provided the optoelectronic device according to the first aspect, wherein the epoxy resin is made of a bisphenol A type, a bisphenol F type, and a first epoxy resin comprising an alicyclic epoxy alone or in combination with the first epoxy resin. It is made of polypropylene glycol diglycidyl ether, which is a second epoxy resin to be provided.

According to the optoelectronic device of the third aspect, the same effect as that of the first aspect is obtained. According to a fourth aspect of the present invention, there is provided the optoelectronic device according to the first aspect, wherein the resin sealing body contains a filler for imparting thixotropic properties. According to the optoelectronic device of the fourth aspect, the predetermined resin shape of the resin sealing body can be maintained.

According to a fifth aspect of the present invention, in the fourth aspect, the filler is silica. According to the optoelectronic device of the fifth aspect, the same effect as that of the fourth aspect is obtained. The optoelectronic device according to claim 6 is the photoelectron device according to claim 1, wherein the epoxy resin is:
Bisphenol A type, bisphenol F type, alicyclic epoxy, alone or in combination, 100 parts by weight of first epoxy resin, 1 to 10 parts by weight of polypropylene glycol diglycidyl ether as second epoxy resin, average particle size 2 to 10 parts by weight of 5 to 50 nm silica,
It contains 1 to 10 parts by weight of a triarylsulfonium hexafluoroantimonate salt-based curing agent.

According to the optoelectronic device of the sixth aspect, the same effects as those of the first, second, third, fourth and fifth aspects are obtained. In addition, with respect to 100 parts by weight of the epoxy resin and 3 parts by weight of the curing agent, the disconnection occurs when the second epoxy resin is 0 parts by weight and the silica is 2 parts by weight, and the second epoxy resin and the silica are 12 parts by weight. In this case, resin peeling occurs. When 100 parts by weight of epoxy resin, 4 parts by weight of polypropylene glycol diglycidyl ether and 6 parts by weight of silica are used, curing is insufficient when the curing agent is 0.5 part by weight, and disconnection occurs when the curing agent is 11 parts by weight. .

According to a seventh aspect of the present invention, in the first aspect, the resin sealing body is an epoxy resin having a viscosity of 5,000 to 30,000 cps. According to the optoelectronic device of the seventh aspect, the same effect as that of the sixth aspect can be obtained. An eighth aspect of the present invention provides an optoelectronic device according to the first aspect, which has a substantially hemispherical shape in which a large number of resin sealing bodies are formed on a substrate.

According to the optoelectronic device of the eighth aspect, in addition to the effect of the first aspect, the present invention can be applied not only to linearly aligning elements but also to a display device and the like arranged in a matrix. In the optoelectronic device according to claim 9, in claim 1, claim 2, claim 3, claim 4, claim 5, claim 6, claim 7, or claim 8, the element is a light emitting diode.

According to the optoelectronic device of the ninth aspect, the same effect as that of the first, second, third, fourth, fifth, sixth, seventh or eighth aspects is obtained. .

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of a light emitting diode light source which is an optoelectronic device according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view of this embodiment, and FIG. 2 is a sectional view taken along line XX of FIG. 1 and 2, 21 is a printed wiring board, 22 is a light emitting diode chip, 23 is a thin metal wire,
24 is a transparent resin sealing body, 25 is a conductor formed in a predetermined pattern, and 26 is a current limiting resistor for maintaining a current to the light emitting diode chip 22 at a predetermined value. The printed wiring board 21 is obtained by cutting a fixed size sheet into a work size, simultaneously forming the conductors 25 of the respective wiring circuit patterns as a multi-piece configuration for cost reduction, and finally dividing the conductor into predetermined dimensions. is there. The light emitting diode chip 22 is provided at a predetermined position on each conductor 25 as shown in FIG.
As shown in (1), one electrode is connected by being mounted on a straight line, and the other electrode is connected to a predetermined portion of another conductor 25 'by a thin metal wire 23. The light emitting diode chip 22 and the conductor 25 and the fine metal wire 23 to which the light emitting diode chip 22 is electrically connected are sealed and protected by a transparent resin sealing body 24 on the main surface of the printed wiring board 21. . As shown in FIG. 1, the transparent resin sealing body 24 has a substantially hemispherical shape from a conventional monolithic body so as to be more resistant to bending of the printed wiring board 21, and is a triarylsulfonium hexacene as a cationic polymerization-based curing catalyst. A fluoroantimonate salt-based curing agent is employed. The light emitting diode chip 22 and the fine metal wire 23 for electrically connecting the light emitting diode chip 22 are sealed and cured on the main surface of the printed wiring board 21 in a state where the viscous flow is prevented. It is desirable that the transparent resin material has a high thixotropic property that can withstand the bending, expansion and contraction of the printed wiring board 21 and can be sealed and cured in a predetermined shape while preventing the viscous flow. For this reason, it is preferable to contain silica as a filler.

[0021]

[Table 1]

As shown in Table 1, the inventor changed the mixing ratio of polypropylene glycol diglycidyl ether as the second epoxy resin to 100 parts by weight of the first epoxy resin, and carried out a pressure cooker bias test (condition Ta = 121 ° C., 2 atm, rated voltage, 48 hours). In addition, about silica, average particle diameter 5-50n
m, and an amount capable of maintaining the sealing shape was added. As the curing agent, 3 parts by weight of a triarylsulfonium hexafluoroantimonate salt-based curing agent dissolved in an organic solvent was blended.

As is clear from Table 1, the mixing ratio of the first epoxy resin to polypropylene glycol diglycidyl ether is suitably 1 to 10 parts by weight of polypropylene glycol diglycidyl ether per 100 parts by weight of epoxy resin. In order to ensure thixotropic property having a resin height capable of sealing the light emitting diode chip 22 and the thin metal wires 23, it was necessary to add 2 to 10 parts by weight of silica having an average particle size of 5 to 50 nm. The viscosity of the epoxy resin after blending is 5,000 to 30,000 c.
ps.

The epoxy resin is bisphenol A
Type, bisphenol F type, and alicyclic epoxy were used alone or in combination, and the same results were obtained.

[0025]

[Table 2]

Next, Table 2 was used to confirm the mixing ratio of the curing agent.
Pressure cooker bias test (condition Ta = 121 ° C., 2 atm, rated voltage, 48 hours) by changing the blending ratio of the triarylsulfonium hexafluoroantimonate salt-based curing agent dissolved in the organic solvent as shown in
Was performed, the results shown in Table 2 were obtained. The other components were 100 parts by weight of epoxy resin, 4 parts by weight of polypropylene glycol diglycidyl ether, and silica had an average particle size of 5 parts.
6 to 50 parts by weight.

As is evident from Table 2, the appropriate mixing ratio of the triarylsulfonium hexafluoroantimonate salt-based curing agent dissolved in the organic solvent is 1 to 10 parts by weight. In addition, it was confirmed that the solvent in which the triarylsulfonium hexafluoroantimonate salt was dissolved did not particularly affect the properties.

[0028]

[Table 3]

The light emitting diode light source 1 employing the epoxy resin encapsulating body 24 using the triarylsulfonium hexafluoroantimonate salt-based curing agent, which is the cationic polymerization-based curing catalyst of this embodiment, was prepared. , A result as shown in Table 3 was obtained. The evaluation results of the light emitting diode light source using the conventional silicone resin are also shown.

As apparent from Table 3, the product of the present invention employing the epoxy resin sealing body 24 using the triarylsulfonium hexafluoroantimonate salt-based curing agent as a cationic polymerization-based curing catalyst is different from the conventional product. A remarkable effect on external pressure was obtained.

[0031]

[Table 4]

Further, a destruction test of the resin sealing body 24 with respect to the bending of the printed wiring board 21 under each use environment was performed. The evaluation results of the light-emitting diode light source employing the acid anhydride-based epoxy resin are also shown. As is clear from Table 4, the product of the present invention employing the epoxy resin sealing body 24 using the triarylsulfonium hexafluoroantimonate salt-based curing agent, which is a cationic polymerization-based curing catalyst, has a lower yield than conventional products. Has stable characteristics in high temperature range.

The evaluation results show that the addition of a long-chain component such as polypropylene glycol diglycidyl ether for imparting flexibility lowers the glass transition temperature, plasticizes the resin, and increases the strength against external stress. It depends.

[0034]

[Table 5]

Next, when the life was confirmed, the results shown in Table 5 were obtained. The evaluation results of a light emitting diode light source employing a conventional acid anhydride-based epoxy resin are also shown. As is clear from Table 5, the product of the present invention employing an epoxy resin sealed body using a triarylsulfonium hexafluoroantimonate salt-based curing agent, which is a cationic polymerization-based curing catalyst, has a longer service life than conventional products. Has stable characteristics for test items.

An acid anhydride curing agent generally used as a light emitting diode chip encapsulating resin material is an epoxy resin and
Even if it is blended in an equivalent amount and cured by heating, a small amount of unreacted curing agent remains. In such a situation, when the light emitting diode chip is energized in a high temperature and high humidity environment, moisture from the outside reaches the light emitting diode chip while extracting the unreacted curing agent. Since the water containing the unreacted curing agent exhibits strong acidity, it promotes electrical corrosion of the P-side electrode of the light emitting diode chip under a high-temperature and high-humidity environment, resulting in disconnection.

According to this embodiment, the curing system does not use an acid anhydride curing agent, and no electrode corrosion due to the unreacted curing agent occurs. In addition, each light emitting diode chip 2
2 and the resin sealing body 24 of the fine metal wire 23 is an epoxy resin sealing body using polypropylene glycol diglycidyl ether and a triarylsulfonium hexafluoroantimonate salt-based curing agent which is a cationic polymerization-based curing catalyst. There is no deformation or destruction of the light emitting diode chip 22 and the thin metal wire 23 due to external pressure, and no destruction or peeling of the sealing resin due to the difference in bending, expansion or contraction of the printed wiring board 21. It has become possible to provide possible products.

Furthermore, the triarylsulfonium hexafluoroantimonate salt-based curing agent, which is a cationic polymerization-based curing catalyst, has a high activation temperature, and an epoxy resin using this curing agent does not progress the curing reaction up to 90 ° C. Since the resin can be made into one liquid, the assembling process can be shortened and the number of steps can be reduced, and further cost reduction can be realized.

In the above description, an example was described in which the light emitting diode chips 22 were linearly arranged and mounted, but as shown in FIG.
The same applies to a display device in which hemispherical transparent resin sealing bodies 24 each of which is sealed are arranged in a matrix. Further, although the description has been given of the example in which the light emitting element is configured by the light emitting diode, the present invention can be similarly applied to other light emitting elements such as a laser and an EL. And it can also be implemented for a light receiving device.

[0040]

According to the optoelectronic device of the present invention, the light-emitting diode chip and the thin metal wire can be prevented from being deformed or broken by the external pressure because they are strong against external pressure, bending, expansion and contraction and electrode corrosion. It is possible to prevent destruction and peeling of the sealing resin due to bending of the printed wiring board and differences in expansion and contraction, and furthermore, it is possible to realize improvement in reliability against electrode corrosion. Furthermore, it is possible to provide a product that is easy to assemble and that can respond to cost reduction.

According to the optoelectronic device of the second aspect, in addition to the effect of the first aspect, it is possible to use one liquid of the epoxy resin, thereby shortening the assembling process and reducing the number of steps, and further reducing the cost. realizable. According to the optoelectronic device of the third aspect, the same effect as that of the first aspect is obtained. According to the optoelectronic device of the fourth aspect, the predetermined resin shape of the resin sealing body can be maintained.

According to the optoelectronic device of the fifth aspect, the same effect as that of the fourth aspect is obtained. According to the optoelectronic device of the sixth aspect, the same effects as those of the first, second, third, fourth and fifth aspects are obtained. According to the optoelectronic device of the seventh aspect, the same effect as that of the sixth aspect can be obtained. According to the optoelectronic device of the eighth aspect, in addition to the effect of the first aspect, the present invention can be applied not only to linearly aligning elements but also to a display device and the like arranged in a matrix.

According to the optoelectronic device of the ninth aspect, the same effect as that of the first, second, third, fourth, fifth, sixth, seventh or eighth aspects is obtained. .

[Brief description of the drawings]

FIG. 1 is a perspective view of a light emitting diode light source according to an embodiment of the present invention.

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

FIG. 3 is a perspective view of a display device according to another embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating an example of a conventional image scanner.

FIG. 5 is a perspective view of the light emitting diode light source.

FIG. 6 is a sectional view taken along the line YY.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Printed wiring board 22 Light emitting diode chip 23 Metal thin wire 24 Resin sealing body 25 Conductor 26 Current limiting resistor

Claims (9)

[Claims] 1. A resin sealing body comprising: a substrate; an element mounted on and connected to the substrate for receiving or emitting light; and a translucent resin sealing body sealing the element on the substrate. Is an epoxy resin using a cationic polymerization-based curing catalyst. 2. The optoelectronic device according to claim 1, wherein the cationic polymerization curing catalyst is a triarylsulfonium hexafluoroantimonate salt curing agent. 3. A first epoxy resin comprising an epoxy resin of bisphenol A type, bisphenol F type and alicyclic epoxy alone or a combination thereof, and polypropylene glycol which is a second epoxy resin for imparting flexibility. 2. The optoelectronic device according to claim 1, comprising diglycidyl ether. 4. The optoelectronic device according to claim 1, wherein the resin sealing body contains a filler for imparting thixotropic properties. 5. The optoelectronic device according to claim 4, wherein the filler is silica. 6. The epoxy resin is a bisphenol A type,
Bisphenol F type, 1 to 10 parts by weight of polypropylene glycol diglycidyl ether as the second epoxy resin, 100 parts by weight of the first epoxy resin alone or in combination of alicyclic epoxy, average particle diameter 5 to 5
2 to 10 parts by weight of 50 nm silica and 1 part of triarylsulfonium hexafluoroantimonate salt-based curing agent
2. The optoelectronic device according to claim 1, wherein the optoelectronic device contains from 10 to 10 parts by weight. 7. The resin sealing body is 5,000 to 30,000 cp.
2. The optoelectronic device according to claim 1, wherein the viscosity is s. 8. The optoelectronic device according to claim 1, wherein a large number of resin sealing bodies are formed on the substrate and have a substantially hemispherical shape. 9. The device according to claim 1, wherein the device is a light emitting diode.
Claim 2, Claim 3, Claim 4, Claim 5, Claim 6,
An optoelectronic device according to claim 7 or claim 8.