Method for manufacturing light emitting device

Abstract

To provide a stable light emitting device and a method for manufacturing the same that do not affect conditions related to light emission, such as a color temperature of light emitting diodes, while providing waterproof performance and protection of light emitting diodes.SOLUTION: It has a light emitting substrate manufacturing process for manufacturing a substrate section (15) in which a light emitting diode (10), which emits light by supplied electric power and in which LED elements are encapsulated with a resin, is arranged, and a sealing process in which a sealing member is made at a temperature above or equal to the glass transition point of the sealing member (20) but below or equal to its melting point, and the sealing member is pressed by a difference in an air pressure to seal at least the light emitting diode with the sealing member, while providing a space (R) between the sealing member and the light emitting diode, and the sealing process includes a vacuum process in which air is left behind by medium to high vacuum.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a light-emitting device that uses a light-emitting diode as a light source and has improved waterproof performance. [Background technology]

[0002] High-brightness LEDs have been used as light-emitting diodes that consume little power and are a high-brightness light source, and light-emitting devices and lighting devices using these high-brightness LEDs have been proposed. Light-emitting devices using high-brightness LEDs have been used as lighting devices for use in lighting inspection equipment and for ceilings and walls of buildings. In addition, high-brightness light-emitting diodes have been proposed as light-emitting devices used not only in lighting devices but also in interiorly illuminated signboards, and practical functions are desired when using surface light emitters containing high-brightness light-emitting diodes for various purposes. One example is the increasing variety of light-emitting colors to match the design of lighting devices, signs, etc., and light-emitting diodes with various color temperatures are being used for white light alone. In addition, there is a demand for the development of light-emitting devices with enhanced waterproofing so that they can be used outdoors.

[0003] For example, Patent Document 1 describes a surface light emitter that is made up of a bendable substrate having electrical wiring, a plurality of LED elements arranged in a generally regular pattern on the substrate, and a top film that is stretched over the surface of the LED elements, and that is characterized in that the top film is attached by being sufficiently in close contact with the uneven shape of the LED elements when stretched over the substrate. Specifically, the invention includes an invention that is manufactured by a vacuum pressure bonding method in which a vacuum is created between the LED elements and the top film, and the heated top film is pressure bonded to the surface of the LED elements.

[0004] For example, Patent Document 2 discloses an invention comprising a substrate portion (15) on which a light-emitting diode (10) that emits light by the supplied power and has an LED element encapsulated with resin is disposed, a sealing member (20) that seals at least the light-emitting diode in a sealed state, and a space portion (R1, R2) provided with a space between the sealing member and the light-emitting diode.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Disclosure of the Invention

Problems to be Solved by the Invention

[0006] In a conventional light-emitting device, the waterproof performance is enhanced by coating the surface of a light-emitting diode with a film by a method of evacuating and crimping the film. Thus, although an invention for eliminating the specular reflection generated in the film by removing air pockets is disclosed in the method of evacuating and crimping the film, in a method of manufacturing without creating air pockets, the film is more surely adhered and stretched to the uneven shape of the light-emitting diode.

[0007] However, in the method of evacuating and crimping the film while applying temperature and pressure to the light-emitting diode 310 with the film, as shown in FIG. 7(A), the film 320 adheres in the direction of the substrate 330 while slightly stretching. After the film 320 is crimped to the light-emitting device, the film 320 shrinks when cooled, and as shown in FIG. 7(B), along with the shrinkage, the entire housing of the light-emitting diode 310 deforms, and the lower part is crushed and the light-emitting diode 310 deforms into a trapezoidal shape.

[0008] At that time, the encapsulating resin 315 inside the light-emitting diode 310 also deforms into a trapezoidal shape or the like. The light-emitting diode 310 formed in this way has a different color temperature from the light-emitting diode not encapsulated by the film 320. Therefore, there is a difference in color temperature from the light-emitting diode not encapsulated by the film 320, and it has been found that this greatly affects the design when designing a lighting device or a signboard.

[0009] The present invention provides a method for manufacturing a stable light-emitting device that achieves waterproof performance and protection of a light-emitting diode while not affecting conditions related to light emission such as the color temperature of the light-emitting diode.

Means for Solving the Problems

[0010] A light-emitting substrate manufacturing step of manufacturing a substrate portion on which a light-emitting diode in which an LED element that emits light by supplied power is encapsulated with resin is arranged, A sealing step of pressing the sealing member at a temperature equal to or higher than the glass transition point and lower than the melting point of the sealing member by a pressure difference to seal at least the light-emitting diode with the sealing member, and sealing while providing a space between the sealing member and the light-emitting diode, The sealing step in the previous stage is characterized by including a vacuum step performed in a state where air is left by vacuum from medium vacuum to high vacuum.

Effects of the Invention

[0011] Due to the above characteristics, the light-emitting device of the present invention can not only enhance the waterproof performance by the close adhesion of the sealing member, but also seal without impairing the color temperature of the light-emitting diode.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0013] The manufacturing method of the light-emitting device according to the present invention will be described in detail with reference to the drawings. Note that the embodiments and drawings described below are examples of a part of the embodiments of the present invention, and are not used for the purpose of limiting to these configurations, and can be appropriately changed without departing from the gist of the present invention. In the present invention, the means for solving the problem by the manufacturing method at the time of encapsulation below and the means for solving the problem by the protective member will be described.

[0014] (Example 1) <Structure of the Light-Emitting Device> The structure of the light-emitting device 1 will be described with reference to FIGS. 1 to 4. FIG. 1 is an overall perspective view of the light-emitting device 1 of the embodiment. FIG. 2 is a cross-sectional view taken along line A-A in FIG. 1 of the light-emitting device 1 of the embodiment. FIG. 3 is an outline of a side view of the light-emitting device 1 of the embodiment viewed from the side. FIG. 4 is a schematic diagram showing the printed pattern portion of the light-emitting device of the embodiment.

[0015] The light-emitting device 1 has a light-emitting diode 10 soldered to a long substrate 15 on which a printed pattern portion 8 is formed, in accordance with the position of the solder portion 11 of the light-emitting diode 10. In addition to the light-emitting diode 10, the substrate 15 mounts electronic components 6 such as a terminal portion 5, a resistor 6a, and an IC chip 6b. Further, as shown in FIG. 1 or FIG. 2, the light-emitting device 1 is entirely covered by a sealing material 20 made of a copolymer polyamide, including the substrate 15, the electronic component 6, and the light-emitting diode 10. Also, the light-emitting device 1 adheres the sealing material 20 by the manufacturing method described later, not only enhancing the waterproof performance but also being sealed without impairing the color temperature of the light-emitting diode 10.

[0016] As shown in FIG. 1, the light-emitting device 1 forms a protective space portion R in a dome shape to secure a space with the sealing material 20, including the light-emitting diode 10 mounted on the substrate 15 and the solder portion 11 sealed by the sealing material 20.

[0017] The light-emitting device 1 provides a protective space portion R as a space (the region of the broken line) so as not to press-contact the light-emitting diode 10, including the solder portion 11, from the side and upward directions. This dome-shaped protective space portion R can not only prevent the deformation of the sealing resin but also protect against external impacts.

[0018] As shown in FIG. 3, the thickness (t4) of the substrate 15 is 0.14 mm, the height (t1) of the resistor 6a from the substrate 15 is 0.5 mm, the height (t3) of the IC chip 6b from the substrate 15 is 1.2 mm, and the height (t2) of the light-emitting diode 10 from the substrate 15 is 0.77 mm.

[0019] And the height of the highest point of the light-emitting diode 10 forming the protective space portion R needs to be 0.5 mm or more. Also, the height of the highest point of the light-emitting diode 10 needs to be 3 to 5 times or more the thickness of the substrate 15.

[0020] Also, the surface of the light-emitting diode 10 forming the protective space portion R is preferably covered with a resin or the like having a low thermal conductivity. Conversely, the resistor 6a and the IC chip 6b, which are the portions to be sealed, have good heat conduction, and it has been confirmed that their temperature is higher than that of the resin when heated to 84°C.

[0021] As shown in FIGS. 2 and 4, the printed pattern portion 8 is provided on the front surface, back surface, or inside of the substrate 15. The printed pattern portion 8 occupies more than 50% of the area of the substrate 15. In this way, since the printed pattern portion 8 occupies more than 50% of the area of the substrate 15, heat is easily transmitted to the substrate 15. The printed pattern portion 8 is made of a conductor metal typified by copper or the like. The thermal conductivity of the printed pattern portion 8 typified by copper or the like is preferably 100 to 400 W / m·K.

[0022] In addition, the substrate 15 used in this embodiment is based on a paper base phenolic resin copper-clad laminate, a glass cloth base epoxy resin laminate, a glass cloth base epoxy resin laminate, or a glass composite base epoxy resin copper-clad laminate. For a highly flexible substrate 15, it is composed of a material based on polyimide or polyester.

[0023] The resin for encapsulating the light-emitting diode 10 LED element uses a plastic resin, such as an epoxy resin, an unsaturated polyester resin, a polypropylene resin, or the like. The thermal conductivity of this resin is 0.2 to 5 W / m·K.

[0024] <Manufacturing method of the light-emitting device> Next, with reference to FIGS. 5 and 6, the manufacturing method for the above-described light-emitting device 1 will be described. FIGS. 5 and 6 are explanatory diagrams showing the manufacturing process for encapsulating the light-emitting device 1 of the embodiment.

[0025] As shown in FIG. 1 or FIG. 5(A), first, the substrate 15 on which all components such as the electronic component 6 and the light-emitting diode 10 are mounted is placed on the workbench 80, the upper arm 99 is lowered, and the upper box 96 and the lower box 95 are fitted together to form an airtight state. Next, the pressures P1 and P2 are adjusted by the pressure adjustment tubes 92 and 93 to evacuate the inside of the upper box 96 and the lower box 95.

[0026] As shown in Fig. 5(B), the temperature inside is raised by the heater 91. At this time, for example, a copolymer polyamide with a thickness of 50 to 100 microns is used as the sealing material 20j, and it is heated by raising the temperature from room temperature to 84°C over 24 seconds. The heating time of the sealing material 20 is preferably a short time within 20 seconds to 1 minute. The melting point of the resin of the sealing material 20 is 90°C to 160°C, and since the glass transition point of this resin is around 50°C, the temperature in the range from the glass transition point to the melting point is controlled.

[0027] Next, the sealing material 20j that has become rubbery due to this temperature droops as shown in Fig. 5(B), but as shown in Fig. 6(C), the pressures P3 and P4 are adjusted by the pressure adjustment tubes 92 and 93 so that the pressure adjustment tubes 92 and 93 adjust the pressures P3 and P4 so that the sealing material 20j is slightly lifted upward to easily form a dome shape.

[0028] Then, as shown in Fig. 1 or Fig. 6(D), while maintaining the temperature at 84°C, the pressure P6 is set from 100 Pa to 10 μPa, which is from high vacuum to medium vacuum, and the pressure P5 is set to atmospheric pressure of 101.3 kPa. The sealing material 20 is pressure-bonded to the substrate 15 including the light-emitting diode 10 and the electronic component 6, and further, 200 kPa of compressed air is sent in to closely adhere the substrate 15 including the light-emitting diode 10 and the electronic component 6 and the sealing material 20j.

[0029] At this time, since it is not ultra-high vacuum of 0 kPa, there is dissolved air present. Also, the substrate 15 and the electronic component 6 with high thermal conductivity are in a state of higher temperature compared to the part of the light-emitting diode 10, and the rubbery sealing material 20 adheres. On the other hand, the part of the light-emitting diode 10 with low thermal conductivity has a lower degree of becoming rubbery, and the air in the substrate 15 and the electronic component 6 is pushed out, and that air gathers to form the protective space part R.

[0030] Finally, the inside of the upper box 96 and the lower box 95 is returned to atmospheric pressure, the upper arm 99 is raised, the fitting of the upper box 96 and the lower box 95 is released, and the light-emitting device 1 is taken out. At that time, the heater is turned off and the operation of returning from 84°C to room temperature is started.

[0031] Also, in the case of double-sided sealing as well, a sealing material 20k is laid on the workbench 80, and a substrate 15 on which all components such as electronic components 6 and light-emitting diodes 10 are mounted is placed on the sealing material 20k. Further, a sealing material 20j is laid from above the substrate 15, the substrate 15 is sandwiched between the sealing material 20k and the sealing material 20j, temperature control and pressure conditions as described above are set, and a light-emitting device 1 is manufactured while forming a dome shape for sealing.

[0032] By the above manufacturing method, the above-described dome-shaped protective space portion R is formed, and the light-emitting diode 10 did not deform even after cooling. At a temperature of 84°C, the resin changes to a rubbery state, but if it is molded at 105°C exceeding the melting point as in the conventional case, it becomes quite soft and adheres to the light-emitting diode 10, compresses the light-emitting diode 10 after the resin cools, and deforms it to the sealing resin 315 (FIG. 7), resulting in a change in color temperature. In this way, the deformation of the light-emitting diode 10 is prevented by temperature control of the resin before it changes to the state of adhesion.

[0033] The resin used for the sealing material 20 is not limited to polyamide resin, and any film-like resin that transmits light may be used. Applications such as polyethylene terephthalate, polyester, polyimide, vinyl chloride, and epoxy resin are desirable. Also, temperature control can be applied to a manufacturing method by vacuum pressure bonding to the extent that a space such as an air pocket is formed between the light-emitting diode 10 and the film in the range from the glass transition point to below the melting point.

[0034] In addition, in the embodiment of the present invention, an example using a plurality of light-emitting diodes 10 is shown, but the light-emitting diode may be a single unit. Also, the light-emitting diode 10 is not limited to single color and may be full color. Further, the present invention is applicable not only to the light-emitting diode 10 but also to light-emitting diodes using phosphors such as organic EL.

[0035] The above-described light-emitting diode 10 has been described in a form in which the LED element is sealed with a sealing resin and a case 12 made of resin on its outer periphery. However, the light-emitting diode 10 may be in a form in which the LED element mounted on the substrate 15 is sealed only with a transparent or translucent sealing resin. Note that the sealing resin may contain a phosphor or a diffusing material. Further, the sealing resin may contain both a phosphor and a diffusing material.

[0036] (Technical Feature) An example of the technical feature points of the present embodiment is shown in parentheses below. However, the present invention is not particularly limited and is merely illustrative, and the effects considered from these features are also described.

[0037] <First Feature Point> A light-emitting substrate manufacturing step of manufacturing a substrate portion (for example, mainly the substrate 15) on which a light-emitting diode (for example, mainly the light-emitting diode 10) that emits light by the supplied power and seals the LED element with resin is disposed; A sealing step of pressing the sealing member (for example, mainly the sealing material 20) at a temperature equal to or higher than the glass transition point and lower than the melting point of the sealing member by a pressure difference to seal at least the light-emitting diode with the sealing member, and sealing while providing a space (for example, mainly the protection space portion R) between the sealing member and the light-emitting diode; The sealing step is characterized by including a vacuum step performed in a vacuum from medium vacuum to high vacuum while leaving air.

[0038] Due to the above features, the light-emitting device of the present invention can not only enhance the waterproof performance by closely adhering the sealing member, but also seal the light-emitting diode without impairing the color temperature of the light-emitting diode.

[0039] <Second Feature Point> The substrate portion is characterized in that the printed pattern portion (for example, mainly the printed pattern portion 8) occupies an area of 50% or more of the substrate. Due to the above characteristics, in a part with a high thermal conductivity like the printed pattern part, heat is easily transmitted even with short-time heating, so the sealing member is likely to become rubbery and is likely to adhere closely to the substrate.

[0040] <Third characteristic point> The light-emitting diode is characterized in that the LED element is sealed with a resin having a lower thermal conductivity than the substrate. Due to the above characteristics, in a part with a high thermal conductivity like the printed pattern part, heat is easily transmitted even with short-time heating, so the sealing member is likely to become rubbery and is likely to adhere closely to the substrate. Also, in a location with a low thermal conductivity, the shorter the time, the more difficult it is for heat to be transmitted, and it is difficult to become rubbery. Therefore, air is likely to gather at the location where the temperature is low, so air is likely to gather at the location of the light-emitting diode and a protection part is formed.

[0041] <Fourth characteristic point> The sealing process is characterized in that the time for heating the sealing member is a short time within 1 minute and includes a heating process for heating the sealing member. Due to the above characteristics, in a part with a high thermal conductivity like the printed pattern part, heat is easily transmitted even with short-time heating, so the sealing member is likely to become rubbery and is likely to adhere closely to the substrate. Also, in a location with a low thermal conductivity, the shorter the time, the more difficult it is for heat to be transmitted, and it is difficult to become rubbery. Therefore, air is likely to gather at the location where the temperature is low, so air is likely to gather at the location of the light-emitting diode and a protection part is formed.

Industrial applicability

[0042] Since it has waterproof performance, it can also be used as a lighting device for exterior parts of automobiles, lighting devices for outdoor and indoor commercial facilities, lighting devices for inspection, lighting devices for refrigerators and decorative showcases, and lighting devices using light-emitting devices in libraries, art galleries, etc.

Explanation of symbols

[0043] 1... Light-emitting device, 5... Terminal part, 6... Electronic component, 8... Printed pattern part, 10... Light-emitting diode, 11... Solder part, 12... Case, 13... Light-emitting surface, 15... Substrate, 20... Encapsulant, 24... Pressing part, 80... Workbench, 91... Heater, 92·93... Pressure regulating tube, 94... Lower arm, 95... Lower box, 96... Upper box, 99... Upper arm, R... Protection space part.

Claims

1. A light-emitting substrate manufacturing process for manufacturing a substrate portion on which a light-emitting diode in which an LED element is encapsulated with a resin and emits light by supplied power is disposed; A sealing process of pressing the sealing member at a temperature equal to or higher than the glass transition point and lower than the melting point of the sealing member by a pressure difference, and sealing at least the light-emitting diode with the sealing member while providing a space between the sealing member and the light-emitting diode; The manufacturing method of a light-emitting device, characterized in that the sealing process includes a vacuum process performed in a state where air is left by vacuum from medium vacuum to high vacuum.

2. The manufacturing method of the light-emitting device according to Claim 1, characterized in that the substrate portion occupies an area of 50% or more of the substrate in the printed pattern portion.

3. The manufacturing method of the light-emitting device according to Claim 1, characterized in that the light-emitting diode encapsulates the LED element with a resin having a lower thermal conductivity than the substrate portion.

4. The manufacturing method of the light-emitting device according to Claim 1, characterized in that the sealing process includes a heating process of heating the sealing member for a short time within 1 minute.

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