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Generally, injection molding technique is applied to fabricate the traditional light guiding plate (LGP). MEMS and hot-embossing
techniques applied to fabricate the concentric circle light guiding plate (CCLGP) in this research. The concentric circle
v-groove structure and the micro-pyramid structure are constructed on the CCLGP. Therefore, the new...
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... backlight module applied in TFT-LCD which is consists of the light source (as a cold cathode lamp), light guiding plate (LGP), prism sheets, diffusive sheets and a reflective sheet and shown in Fig. 1. Following the development of the thin-LCD, many researchers improve the traditional backlight module and make it thinner, lighter, and brighter which has already become the trend. The LGP made by Polymethyl methacrylate (PMMA) material which is a very important optical component in backlight module. Injection molding technology is ...
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... the polyimide is spun on the (100)-oriented silicon wafer with nitride (Si 3 N 4 ). After that, the pattern is defined through lithography process. RIE process is used to etch the nitride layer. After the unexposed-PR is stripped, anisotropic etching process is applied to make pyramid mould. Finally, the pyramid mould is completed and shown in Fig. ...
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... material is used to fabricate the CCLGP with micro-structure on the double-side surface using hot embossing technology and shown in Fig. 12 ...
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... illuminative test unit (including the light source, optical illuminator, optical plate and black box) is ap- plied to measure the CCLGP and shown in Fig. 15. The white LED could be as the light source of the CCLGP. The nine test positions on the CCLGP are chosen to be measured the illumination with 1 · 1 cm 2 and shown in Fig. 16. ...
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... illuminative test unit (including the light source, optical illuminator, optical plate and black box) is ap- plied to measure the CCLGP and shown in Fig. 15. The white LED could be as the light source of the CCLGP. The nine test positions on the CCLGP are chosen to be measured the illumination with 1 · 1 cm 2 and shown in Fig. 16. ...
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... mould V-groove mould PMMA material Fig. 12 Hot-embossing process White LED Fig. 15 The illuminative measurement set up of CCLGP Microsyst Technol (2007Technol ( ) 13:1529Technol ( -1535Technol ( 1533 First type of the LGP is the non-prism LGP and Table 2 shows the tested illumination data. The maximum illumination is 138.2 lux and the minimum illumination is 72.7 lux; ...
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... mould V-groove mould PMMA material Fig. 12 Hot-embossing process White LED Fig. 15 The illuminative measurement set up of CCLGP Microsyst Technol (2007Technol ( ) 13:1529Technol ( -1535Technol ( 1533 First type of the LGP is the non-prism LGP and Table 2 shows the tested illumination data. The maximum illumination is 138.2 lux and the minimum illumination is 72.7 lux; therefore, the uniformity of illumination is 52%. ...
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... The maximum illumination is 365.7 lux and the minimum illumination is 300.7 lux; therefore, the uniformity of illumination is 82%. From the above measured results, the uniformity of the CCLGP is demonstrated better than other types of LGPs and shown in Table 6. The relationship of the illuminative uniformity of four different LGPs is shown in Fig. 18. ...
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Citations
... Many experts have devoted a tremendous amount of effort to increasing the qualities of CCFLBLU [1, 2, 3]. Furthermore, many researchers have been executed in efforts to enhance the luminance and uniformity of LED BLU by optimizing the microstructures, size and patterns of diffusive dots on the light guide plate [4, 5, 6, 7]. For improving the efficient and the luminous uniformity of the BLU, the design of LED reflector is considered. ...
An edge-backlight unit (EBLU) is applied as the light device to provide uniform light of liquid crystal display (LCD). Generally, the cathode cold fluorescent lamp (CCFL) is employed as the light source of BLU. With the advantages such as long durability, no mercury substance and good endurance of heavy impact, the light emitting diode (LED) is now accepted well known as available device for solid state lighting. To achieve the market requirement of the thin-film liquid crystal display (LCD) and the green-level product, the LED is replaced with the CCFL used in monitor in order to make display thinner, lighter, no Hg containing. In this paper, the integrated LED reflector is proposed because it enables the point-like light to distribute propagating-light line pattern successfully. To optimize the size and the radian of the reflector, our designed integrated LED reflector can achieve an optical efficiency more than 85%, and its light output length is 11 times of the input light source. Therefore, the integrated LED reflector not only can decrease the number of LED to save the built space, but also enhance the output efficiency. In the future, an integrated LED reflector could make displays thinner and brighter for backlight applications.
... Many researchers have devoted a tremendous amount of effort to improving the qualities of CCFL-BLU [2, 3, 4]. Furthermore, many studies have been performed in efforts to increase the luminance and uniformity of LED BLU by optimizing the location, size and patterns of microstructures or diffusive dots on the light guide plate [5, 6, 7, 8]. For realizing the efficient and the uniform luminance of the BLU, design of such an output lightguide is very important. ...
A conventional backlight unit (BLU) is used to as the light module to present uniform light of liquid crystal display (LCD). In general, cold cathode fluorescent lamp (CCFL) is utilized to be the light source of BLU. The light emitting diode (LED) is now considered well known as a promising device for solid state lighting. It has the advantages of long durability, no mercury substance and good endurance of heavy impact. To satisfy the market demands of the thin-film liquid crystal display (LCD) and the green product, the LED is applied to as the light source to make display thinner, lighter, no Hg containing. In this research, the LED uniform lightguide is demonstrated because it enables the point-like light to distribute propagating-light line pattern successfully. By optimizing the size and the radian of the device, the designed LED uniform lightguide can achieve the output efficiency more than 85%, and its illuminative uniformity is improved about 85%. Thus, the LED uniform lightguide not only can decrease the number of LED to save the space, but also enhance the optical efficiency. In the future, a novel LED uniform module could make displays thinner and lighter for backlight system applications.
... Nagasawa fabricated an ultra slim backlight system using optical-patterned film, which has a lot of advantages to be composed of a single component [9]. Chien [10, 11] recommended the integrated light guide plate on microstructure-based by using Microelectromechanical Systems (MEMS) technique for BLU application. There are also many patents, which have been proposed for small size LCD backlight panel In comparison to previous researches and patents, their proposed light guide plate (LGP) is not concerned the LED incident light uniformity, dark band problem and illuminative efficiency, etc. ...
A conventional backlight unit (BLU) is utilized to as the light module to present uniform light of liquid crystal display (LCD). In general, cold cathode fluorescent lamp (CCFL) is used to be the light source of BLU. The light emitting diode (LED) is well known as a promising device for solid state lighting. It has the advantages of long life, no mercury containing and good endurance of heavy impact. To satisfy the market demands of the thin-film liquid crystal display (LCD) and the green product, the LED is applied to as the light source to make display thinner, lighter, no Hg containing. In this research, the LED light-linear device with microprism structure is demonstrated that it can make the point-like light to distribute propagating-light line pattern successfully. By optimizing the distributions and sizes of microprisms, the designed LED-linear device can achieve an illuminative efficiency more than 80%~90%, and its light output area is two times the input light source. Thus, the LED light-linear device with microprsims not only can decrease the LED to save the space, but also increase the optical efficiency. In future, a novel LED light module could make displays thinner and lighter for light guide plate (LGP) applications.
... Feng et al [9] approved a design concept of integrated LGP based on microstructures using polymethylmethacrylate (PMMA) material, to control the illuminative angle. Chien [10,11] recommended the integrated light guide plate on microstructure-based by using Microelectromechanical Systems (MEMS) technique for BLU application. There are also many patents, which have been proposed for small size LCD backlight panel [12, 13, 14]. ...
An edge-backlight unit (EBLU) is applied to as the light device to provide uniform light of liquid crystal display (LCD). Generally, cathode cold fluorescent lamp (CCFL) is utilized to be the light source of BLU. With the advantages like long life, no mercury containing and good endurance of heavy impact, the light emitting diode (LED) is well known as a viable device for solid state lighting. To achieve the market requirement of the thin-film liquid crystal display (LCD) and the green-level product, the LED is replaced the CCFL used in monitor to make display thinner, lighter, no Hg containing. In this paper, the integrated LED luminance-uniform device with right angle microprism structure is proposed that it can make the point-like light to distribute propagating-light line pattern successfully. To optimize the distributions and sizes of microprisms, our designed LED-linear device can achieve an optical efficiency more than 85%, and its light output area is 2.5 times the input light source. Therefore, the LED luminous device with microprsims not only can decrease the LED to save the space, but also enhance the luminous efficiency. In future, an integrated LED luminance-uniform device could make displays thinner and brighter for light guide plate (LGP) applications.
Main technological approaches to production of light-conducting systems with scattering microstructures are considered with a special attention to processing method of the optical material influence on geometrical parameters of the being formed microstructure. Relevance of it is caused by an insufficiency of studying influence of the microstructural scattering element configuration distortion on output luminance distribution of the light-conducting systems (because of the technological features of their production). As exemplified by a light-conducting system made by milling technology, a physically correct simulation of this system is carried out, and influence of the microstructure relief on output luminance distribution is shown. For the simulation, the Lumicept program system was used, which has provided physical correctness of the modelling results. © 2018, LLC Editorial of Journal "Light Technik". All rights reserved.
Many components need microstructures on both upper and lower surfaces for integrating and enhancing functions. For the replication of microstructures on the polymeric substrate, hot embossing is an inexpensive and flexible method. However, the cycle time is too long and the embossing pressure is not uniform. This study is devoted to developing an innovative hot embossing system, which integrates induction heating and gas-assisted pressuring for the imprinting of double-sided microstructures. In this study, a wrapped coil for induction heating was designed, implemented, and tested. Then, an apparatus with wrapped coils for induction heating and gas pressuring for hot embossing was designed and constructed in a chamber. Experiments showed that the cycle time can be reduced to 4 min. V-cut patterns and microlens array had been successfully replicated on both surfaces of the polycarbonate substrates. The replication rates were above 95%. This study proves the potential of induction heating gas-assisted embossing for rapid replication of double-sided microstructures for industrial applications.
The LGP (Light guide plate) plays a key role of the backlight in LCD module. It determines the efficiency and uniformity
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non-sequential ray-tracing. Two semi-analytical formulations are conducted to optimize the micro-dots’ distribution
when LGP is with mirrored or corrugated entrance plane. The ultra-slim LGPs fabricated by solid-state laser and diamond-ruling machine show excellent elimination of the Hotspot phenomenon.
In this study, we demonstrated a simple method that can be used to simultaneously modulate the far field pattern and enhance
the light extraction of GaN-based light-emitting diodes (LEDs). In this method, microstructures were imprinted on a reliable
spin-on-glass surface on top of a transparent conductive layer. The far-field pattern was modulated using microoptical structures,
and at the same time, the light extraction was enhanced owing to the small refractive index difference and surface roughness.
There was no decrease in the electrical performance of these devices. The peak intensity shifted from 0 to 22° in one-dimensional
(1D) asymmetrically blazed periodic structures, and a flattened distribution with a uniform intensity within a span of 110°
was observed in two-dimensional (2D) symmetrically periodic structures. This method achieved 13 and 40% light enhancements
for 1D and 2D structures, respectively.
KeywordsGaN-light-emitting diode (LED)-imprinting technology-far-field pattern modulation-light extraction
