White LEDs still have problems such as poor uniformity of light emission and long life of the sealing material, and it is impossible to exert the application advantages that white LEDs are expected. However, as far as the demand level is concerned, not only the general lighting use, but also the wide application of mobile phones, LCD TVs, automobiles, medical treatments, etc., the technical research results that are most suitable for developing stable white LEDs are widely concerned. To improve the luminous efficiency of white LEDs, there are currently two major directions. One is to increase the area of LED chips , thereby increasing the amount of illumination. The second is to package several small chips together under the same module.
Increase the amount of luminescence by increasing the chip area
Although the area of ​​the LED chip is increased, thereby achieving much higher brightness, due to the excessive area, there is a counterproductive phenomenon in the application process and results. Therefore, in response to such problems, some LED manufacturers have improved on the surface of the chip according to the improvement of the electrode structure and the structure of flip chip. For example, in the portion of the white LED flip chip package, since the light emitting layer is very close to the vicinity of the package, the light of the light emitting layer is not blocked when the light of the light emitting layer is emitted to the outside, but the disadvantage is that the generated heat is not easily dissipated.
Not only after the chip surface is improved, but also by increasing the chip area, the brightness can be quickly increased, because when the light is diffused outward from the inside of the chip, the improved part of the chip cannot be reflected, so it will receive a little bit in the light extraction. According to the calculation, the LED chip size that best utilizes light efficiency is about 7mm2. Using a small number of small-area LED chips to quickly improve the luminous efficiency compared with large-area LED chips, using a small power LED chip to package the same module, so that it can achieve high brightness requirements quickly, for example, Citizen will be 8 small The LEDs are packaged together. However, this kind of practice also raises some doubts. Because multiple LEDs are packaged on the same module, some insulating materials must be placed to avoid short circuit between LED chips. This will increase the number of LEDs. cost.
Citizen's explanation is: "The impact on cost is quite small, because these insulation materials are less than one percent compared to the overall cost ratio, and existing materials can be used for insulation applications. These insulation materials do not need to be redeveloped or added to new equipment. "Although Citizen's explanation is theoretically reasonable, for inexperienced operators, this is a challenge because of the yield. R & D, production engineering are all need to be overcome. There are other ways to achieve the goal of improving luminous efficiency. Many manufacturers have found that the uneven structure is formed on the LED sapphire substrate, which may increase the light output. Therefore, there is a gradual orientation to establish Texture or Photonics crystal on the surface of the chip. The architecture. For example, OSRAM in Germany developed "Thin GaN" high-brightness LEDs with such a structure. The principle is to form a metal film on the InGaN layer, and then peel off the sapphire, so that the metal film will produce a reflection effect and obtain more light. According to the OSRAM data, such a structure can obtain 75% light extraction efficiency. . In addition to the effort required to remove the light from the chip, it is necessary to make some improvements in the package part because it is expected to achieve higher light efficiency. In fact, every additional project will have some impact on the efficiency of light extraction. However, this does not mean that the process of packaging will definitely increase the light loss, just like the planar light source developed by OMROM in Japan. The technology can greatly improve the light extraction efficiency. The structure is to control the light emitted by the LED, using the LENS optical system and the reflective optical system, so the OMROM calls it "Double Reflection". With such a structure, the light loss caused by the LED of a conventional bullet-type package or the like can be obtained by reflecting the wide angle of the package to obtain higher light efficiency, and further, processing on the Mesh formed on the surface, and A double-layered reflection effect is formed, which can achieve good light extraction efficiency control. Because of this special design, LEDs that use reflection effects to achieve high light extraction efficiency are mainly used for LCD TV backlights.
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The whole product is thin in shape, exquisite in quality and exquisite in design. It reflects the aesthetic value of industrial design everywhere. It is a model for the integration of green technology and design art. In the lighting area, the combination of LED backlight and acrylic transfixion is adopted, together with the densely perforated planning of the lighting panel, which makes the modeling more generous and elegant, and also builds a softer application environment for the users. As a public welfare product, the FIZZ GLOBAL strives to achieve the most central functional requirements with the lowest cost in the development process, so that the product can reach the relevant people on a larger scale. Save more information, let the whole lighting more light. During this planning process, FIZZ GLOBAL constantly tested differences, broke the inherent design ideas, and completed new inventions of traditional products.
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