JP2012160664A - White light obtained from blue led, and silicone tape used for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique, with which, at a user side, light emitted from a blue LED can be controlled and, if required, the light can be converted to arbitrary white light.SOLUTION: White light produced by a combination of a blue LED and a yellow phosphor is obtained using a silicone tape including a silicone resin adhesive material layer formed on a surface of a silicone resin sheet in which a yellow phosphor is uniformly blended. The silicone tape is cut in a size sufficient to cover the blue LED, and is adhered on the blue LED with the adhesive material layer.

Description

  The present invention relates to white light based on a blue LED, and proposes a technique that makes it possible to easily obtain such white light.

  Conventionally, it is known that white light can be obtained by mixing light having complementary colors, and the present invention is a new proposal for obtaining white light in combination with a phosphor that emits yellow light using a blue LED as excitation light. .

  As a structure for obtaining white light, there are a method of obtaining white by mixing with LEDs of three primary colors of red, green, and blue, and a method of obtaining white by mixing of blue LED and yellow phosphor. In the latter case, the blue LED has a color function as blue light and a function as excitation light of the phosphor. The present invention relates to white light by the latter method, and generally has a structure in which yellow phosphor powder particles surround a blue LED. Such a yellow phosphor is excited by absorbing blue light, and a phosphor that emits yellow light is used. As described above, since blue light and yellow light are in a complementary color relationship, a mixed color of blue and yellow is perceived as white by human eyes. As the yellow phosphor, an yttrium-aluminum-garnet (YAG: Ce) phosphor activated mainly with cerium is used.

Japanese Patent Application Laid-Open No. 07-099345 Utility Model Registration No. 3048368 Utility Model Registration No. 3117306

  It is based on a blue LED and is obtained by suspending a yellow phosphor in an epoxy resin or an acrylic resin and applying it around the blue LED in white light using a yellow phosphor. For example, what is proposed in Patent Document 1 is to apply white fluorescent light on a blue LED crystal chip to obtain white light.

However, since it is difficult to control the thickness of the fluorescent powder, white light is not uniform. If the fluorescent powder layer is too thick, it is biased to yellow, and if it is too thin, it is biased to blue.

Furthermore, the phosphor suspended in the resin is difficult to be in a uniform state, and the phosphor settles with time, and the concentration of the phosphor in the resin is different at the beginning and end of work, so that white light of the same color is obtained. It was also a fact that it was difficult. Furthermore, if it is a type in which a yellow phosphor is directly attached to a blue LED chip, fine processing is required, and it takes time to manufacture. Moreover, although there are acrylic resins as the resin or the adhesive material layer, there is a drawback that it is weak against heat and easily deteriorates, and further, since these resins are relatively hard, the operation is difficult.

  For this reason, in this type of white light, an already manufactured white LED that is a combination of a blue LED and a yellow phosphor will be purchased from an LED manufacturer, but adjusting the light on the user side Almost no satisfactory white light was always available.

  An object of the present invention is to solve the drawbacks that have been pointed out in the past by simple means, and to control the light emitted from the blue LED on the user side and change it to any white light as necessary. To do.

The first gist of the present invention is white light in which a blue LED and a yellow phosphor are combined, and a silicone tape in which a silicone resin adhesive layer is formed on a silicone resin sheet surface in which the yellow phosphor is uniformly blended is used. The silicone tape is cut to a size sufficient to cover the blue LED, and is adhered to the blue LED with an adhesive layer.

  The second gist of the present invention is a white light in which a blue LED and a yellow phosphor are combined, and a silicone tape in which a silicone resin adhesive layer is formed on a silicone resin sheet surface uniformly blended with a yellow phosphor is used. The silicone tape is cut to a size sufficient to cover the blue LED, and is adhered to the blue LED irradiation surface with an adhesive layer.

  The silicone tape is adhered to the blue LED directly or by forming a gap, and the yellow phosphor used is a phosphor that emits excitation light by the blue LED, and generally a YAG phosphor is used. Preferably, it is 10 to 30% by weight based on the silicone resin.

A third aspect of the present invention is a silicone tape used for white light according to the first and second aspects, wherein the silicone resin sheet surface in which a yellow phosphor is uniformly blended is adhesive to the silicone resin sheet surface. The silicone tape which obtains white light from blue LED characterized by comprising the whole which formed the silicone resin adhesive material layer which provides UV with the silicone.

Such a silicone tape preferably maintains adhesiveness with a silicone resin at −40 ° C. to 200 ° C. and a cushioning property made of a silicone resin containing a yellow phosphor, and has a total light transmittance of 92% at maximum (JIS K7361). ), And a tensile strength after heating at 180 ° C. for 500 hours has a heat resistance of 70% of the initial strength.

  Since the present invention has the above-described configuration, it has been necessary to purchase a ready-made product from an LED manufacturer in order to obtain white light from a blue LED. However, in the present invention, a silicone-based tape is used. By doing so, the customer can easily produce the desired white light.

FIG. 2 is a schematic diagram of an LED system for obtaining the first white light of the present invention. These are the schematic diagrams of the 3rd silicone tape of this invention. FIG. 3 is a schematic view showing an example of a manufacturing process of a silicone tape.

  The first and second aspects of the present invention are methods for obtaining white light by a combination of a blue LED and a yellow phosphor as described above. The yellow phosphor disposed on the blue LED is uniformly blended in the silicone resin. And the silicone tape which formed the adhesive material layer by the silicone resin in this one surface is used. The third invention provides a silicone tape suitable for use in the first and second inventions.

  The reason why blue LEDs and yellow phosphors are used as a method for obtaining white light is that white light can be composed of only a single yellow phosphor, so that adjustment of optical characteristics is easy and conversion efficiency is high, ultraviolet rays This is because the Stokes shift is small compared to the color conversion from, and the essential energy conversion can be improved, and the luminous efficiency is high because the transmitted light of the blue LED can be used. The blue LED emits blue-based visible light such as blue or bluish purple having a wavelength range of 430 nm to 500 nm, and includes, for example, a gallium nitride semiconductor (crystal).

  And as a characteristic of the yellow phosphor to be used, it emits light in visible light or near ultraviolet (having an excitation spectrum suitable for light emission of blue LED), high luminous efficiency (for example, light even at high temperature), chemically stable (In particular, durability against temperature and humidity) is required.

  As the yellow phosphor, the aforementioned yttrium aluminum garnet (YAG: Ce) phosphor is generally used. This is because blue light emitted by the blue LED in the wavelength range of 460 nm to 470 nm is well absorbed and converted into yellow visible light having a wavelength of about 560 nm to 590 nm. In addition, sulfide phosphors such as α sialon and β sialon, and silicate phosphors can also be used. Then, a silicone tape in which these yellow phosphor powders are uniformly mixed is adhered to a blue LED directly or by forming a gap, and generally 10 to 30% by weight based on a silicone resin. is there.

  In the third invention, a silicone resin is particularly used as the resin for supporting and blending the yellow phosphor. Such silicone resin is a material that is easy to handle and has excellent durability, heat resistance, weather resistance, transparency, etc., and the present invention is a highly utilized material, and further has excellent adhesion performance to blue LEDs. It is a drawer.

That is, a yellow phosphor used for a blue LED is uniformly blended in a silicone resin, preferably maintaining flexibility and cushioning, and having a total light transmittance of up to 92% (JIS K7361). ), The tensile strength after heating at 180 ° C. for 500 hours has a heat resistance of 70% of the initial strength, and more specifically, in the temperature range of −40 ° C. to 200 ° C., stable cushioning properties and adhesiveness The purpose is achieved by adopting the silicone tape provided with.

In the third invention, after blending a predetermined amount of the yellow phosphor in the uncured silicone resin, the yellow phosphor is stretched and cured, and then cut into a predetermined width and length to obtain the yellow phosphor. A kneaded silicone resin sheet is obtained, and it is preferable to use a silicone resin that hardly absorbs light having a wavelength of 400 nm to 1000 nm as the organic resin.

Then, an adhesive layer made of a silicone resin having the same effect is formed on one surface of the resin sheet, and the user cuts it into an appropriate size and adheres to the blue LED or the blue LED irradiation surface. Will be. In this way, by selecting a silicone material that has the same effect as the adhesive material layer and using a silicone resin for the entire tape, the material has excellent durability, heat resistance, weather resistance, transparency, and the like. . In addition, the tape shape achieves ease of handling, light uniformity, and reduction in production cost.

That is, the user can obtain the desired white light simply by preparing a blue LED, cutting a silicone tape containing a yellow phosphor into an arbitrary size, and bonding this to the blue LED. The customer can now produce the white light they need.

FIG. 1 is a schematic diagram of an LED system for obtaining a first white light according to the present invention, in which a plurality of depressions 2 are formed in a base 1 and a blue LED 3 is set therein. These blue LEDs are connected to lead wires (not shown), and a blue light is emitted by applying a voltage to the lead wires. Then, the silicone tape 5 is adhered with an adhesive material so as to cover the blue LED 3. This silicone tape 5 is composed of a silicone resin portion 6 and a silicone adhesive layer 7, and a yellow phosphor is uniformly blended in the silicone resin portion 6 so that yellow light is emitted by blue light. .
In the figure, an example is shown in which the silicone tape 5 adheres to all of the blue LEDs 3, but this is optional. For example, by adhering the silicone tape 5 to every other blue LED, the blue light And white light are obtained alternately.

  FIG. 2 is a schematic view of the third silicone tape 5 of the present invention. Now, the silicone tape 5 is composed of a silicone resin portion 6 and a silicone adhesive material layer 7, and the yellow fluorescent material is uniformly blended in the silicone resin portion 6 as described above.

That is, as described in paragraph 0021 and shown in FIG. 3, as a first step, the yellow phosphor 8 is suspended and blended in an uncured silicone resin 6a, and then stretched and cured in a second step. The silicone sheet 6b is formed. Next, as a third step, a silicone tape 5 is obtained by laminating a silicone thin layer 7a to be the adhesive material layer 7 on the surface of the silicone sheet 6b and then cutting it into a predetermined width and length. .

In FIG. 3, a release paper 9 is usually attached to the surface of the adhesive material layer 7, and when attaching to the blue LED 3, the silicone tape 5 is further cut into a desired size, and the release paper 9 Is peeled off to perform adhesion work to the blue LED 3 to obtain a white LED.
Needless to say, it is also possible to apply a thin silicone resin as the adhesive material layer 7 on the surface of the silicone sheet 6b and attach a release paper 9 thereon to form a silicone tape.

  The most significant feature of the present invention is that the yellow phosphor side is composed of a silicone resin (6 and 7) with respect to the blue LED 3, and even the adhesive layer 7 uses the silicone resin 7a to produce white light. It satisfies various requirements suitable for obtaining. Moreover, the silicone tape 5 according to the present invention is flexible and can easily follow the surface shape of the blue LED 3 (or the surface shape of the base 1). The user can cut the tape 5 appropriately. Thus, the desired white light can be easily obtained.

  The white light using the blue LED of the present invention can be easily obtained by using a silicone tape. Therefore, the use range is wide, and various lighting, store lighting, showcase lighting, and back of liquid crystal displays are used. It can be widely used for lights.

1 ・ Base 2 ・ Dimple 3 ・ Blue LED
5. Silicone tape 6. Silicone resin part 7. Silicone adhesive layer 6a Silicone sheet 7a Silicone thin layer (adhesive layer)
8. Yellow phosphor 9. Release paper

Claims (8)

  White light combining a blue LED and a yellow phosphor, and using a silicone tape in which a silicone resin adhesive layer is formed on a silicone resin sheet surface in which the yellow phosphor is uniformly mixed, covers the blue LED with the silicone tape. The white light is characterized by being cut into a size sufficient to adhere to the blue LED with an adhesive layer.   White light combining a blue LED and a yellow phosphor, and using a silicone tape in which a silicone resin adhesive layer is formed on a silicone resin sheet surface in which the yellow phosphor is uniformly mixed, covers the blue LED with the silicone tape. The white light is characterized by being cut to a size sufficient to adhere to the blue LED irradiation surface with an adhesive layer.   The white light according to claim 1 or 2, wherein the silicone tape is adhered to the blue LED directly or by forming a gap.   The white light according to claim 1 or 2, wherein the yellow phosphor is a phosphor that emits excitation light by a blue LED.   4. A silicone tape used for white light according to claim 1, wherein a silicone resin pressure-sensitive adhesive layer that imparts adhesiveness to the silicone resin sheet surface is formed on a silicone resin sheet surface uniformly blended with a yellow phosphor. Silicone tape for obtaining white light from a blue LED.   The silicone tape according to claim 5, wherein the silicone tape maintains stable adhesiveness and cushioning properties at -40 ° C to 200 ° C.   The silicone tape according to claim 5 or 6, wherein the silicone tape is a tape having a maximum total light transmittance of 92% (JIS K 7361).   The silicone tape according to any one of claims 5 to 7, wherein the silicone tape is a tape having a heat resistance of 70% of initial strength after heating at 180 ° C for 500 hours.