The present invention relates to a structure applying an optical wave-guide layer with LED (Light Emitting Diode), and more particularly to a structure using a combination of materials with different optical properties to collect incident light and effectively guide the collected incident light to outside ambient to effectively overcome a drawback of the prior art optical component that loss a portion of the light by reflection loss, absorption, and limitation of the light extraction method.
The optoelectronic industry relates to all business conducts including the manufacture or application of optoelectronic components, and the equipment, tools, and systems that adopt optoelectronic components as key component modules.
As defined by the Optoelectronic Science and Technology Association, the optoelectronic industry is divided into six main categories, respectively: optoelectronic component, optical display, optical input/output, optical storage, optical communication, laser and other optoelectronic applications.
The aforementioned optoelectronic components can be applied to a light-to-electricity converter (or a solar cell), an optical fiber communication, an optical information storage device (such as a laser CD), an optical display and an optical detector.
In the case of LED device, the light loss would happen as follows:
1. Absorption loss: As light emitted from the light emitting layer, it need to pass through several cladding layers before escaping outer ambient. Portion of the emitting light could be absorbed.
2. Reflectivity loss: Generally, when light emitted from light emitting layer. For some particular LED structures, such as, flip-chip and thin-GaN LED, a mirror reflector is used to reflect either upward or downward light. The reflecting light would have certain degree of loss due to the reflectivity.
3. The total-reflection loss: As the emitting light arrive the top surface of LED device (usually III V compound surface), the totally reflection behavior would happen. A significant emitting light would be lost and confined in the LED chip. Only small portion of emitting light can be extracted toward the outer ambient.
It is a subject for manufacturers to develop a new technology to prevent the reflectivity loss, absorption loss, and the totally reflection loss on the top emitting surface, so as to promote the development and advancement of the industry.
In view of the foregoing shortcomings of the light extraction method adopted by a conventional optoelectronic component that still cannot obtain a portion of light, the inventor of the present invention based on years of experience in the related industry to conduct extensive researches and experiments to overcome the shortcomings of the prior art, and finally developed a structure applying an optical wave guide layer in accordance with the present invention.
The primary objective of the present invention is to provide a novel structure applying an optical wave guide layer, adopt a combination of materials having different optical properties, and apply the structure of the optical limit guide layer for guiding the collected incident emitting light. The invention collects the incident emitting light and the effectively prevent the conventional optoelectronic component from being unable of obtaining a portion of the light by the conventional light extraction method. Obviously, the structure of the invention is valuable to the applications in the related industries, such as LED.
To make it easier for our examiner to understand the technical measures and operating procedure of the invention, we use a preferred embodiment together with the attached drawings for the detailed description of the invention.
The invention relates to a structure applying an optical wave guide layer. Referring to
In this invention, the incident light source 20, and at least one optical wave guide layer 40 can be a single-layer film 41 or a multilayer film 42, wherein the single-layer film 41 can be disposed on a continuous surface or an orderly arranged non-discontinuous surface (such as photonic crystal array), and the single-layer film 41 is made of a material with a high light penetrability (such as silicon dioxide, silicon nitride, aluminum nitride, indium tin oxide, zinc oxide, cadmium oxide, aluminum oxide, zinc sulfide, magnesium oxide, cerium oxide, niobium oxide and epoxy resin). The multilayer film 42 can be made of a composition of materials with different refractive indexes and a high light penetrability (such as silicon dioxide, silicon nitride, aluminum nitride, indium tin oxide, zinc oxide, cadmium oxide, aluminum oxide, zinc sulfide, magnesium oxide, cerium oxide, niobium oxide and epoxy resin), and the materials with different refractive indexes are arranged orderly according to the magnitude of the refractive indexes.
With the foregoing structure, the incident light source 20 can be collected, and the collected light can be guided in any other directions (by simply changing the installation direction of at least one optical limit guide layer 40).
Referring to
Step 1 (Wafer bonding): An e-gun evaporator is used for forming an epitaxy made of a Group III˜V material (such as gallium nitride, AlGaN-based ternary compound, aluminum nitride, InGaN-based ternary compound, AlGaInN-based quaternary compound, indium nitride, GaInAsN-based quaternary compound and GaInPN-based quaternary compound) on the surface of an epitaxial layer of an epitaxial substrate 10 (such as sapphire substrate, silicon carbide substrate, zinc oxide substrate and gallium nitride substrate). In the embodiment of the thin GaN LED, the Group III˜V material is an incident light source 20, and a p-type contact metal layer 30 (such as nickel oxide), the optical limit guide layer 40, an electrode layer 50 (such as aluminum and silver), a first bonding metal layer 60, a second bonding metal layer 70 and a high-performance heat dissipating substrate 80 (such as silicon, aluminum nitride, beryllium oxide, copper) is plated onto a surface of the Group III˜V material by a physical deposition method.
Step 3 (Substrate Lift-Off): A substrate lift-off technology (such as laser lift-off) is provided for removing the epitaxial substrate 10.
The epitaxial substrate 10 serves as a substrate for growing the epitaxial layer to produce a good-quality epitaxial layer. The Group III˜V material is used as the main composition of the components. The p-type contact metal layer 30 is provided for reducing the contact energy barrier to improve the using efficiency of the optoelectronic components. The optical limit guide layer 40 is the main technical characteristic of the present invention, which is provided for guiding the incident light source 20 in a specific direction to prevent the occurrence of a common full reflection or absorption that will affect the light extraction efficiency, and the optical limit guide layer 40 can be a single-layer film 41 or a multilayer film 42 (as shown in
The electrode layer 50 serves as a reflecting layer, which is also an electrode of the optoelectronic component, and has the functions of conducting and reflecting a light source. The first bonding metal layer 60 and the second bonding metal layer 70 are materials applied in the wafer bonding process for bonding the metal bonds into one. The high-performance heat dissipating substrate 80 is provided for eliminating the high heat produced during the operation of components to facilitate a stable operation of components.
In summation of the description above, the structure of the optical limit guide layer 40 in accordance with the present invention uses a combination of materials having different optical properties to collect and guide lights, controls the incident angle of the collected light, and selects materials to effectively overcome the shortcoming of the conventional light extraction method for optoelectronic components that cannot obtain a portion of the light. Therefore, any structure capable of collecting an incident light source 20 and guiding the collected light in any direction falls within the scope of the present invention. The present invention complies with the requirements of patent application, and the structure of the invention is valuable to the applications in the related industries (such as LED manufacturing factories, packaging factories and optoelectronic semiconductor packaging factories). Thus, the invention is duly filed for patent application.
While the invention has been described by way of example and in terms of a preferred embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.
Number | Date | Country | Kind |
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096146315 | Dec 2007 | TW | national |