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  • 1
    Electronic Resource
    Electronic Resource
    Analytical Calculation of the Light Extraction Efficiency of Micro Cavities Light-Emitting Diodes (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 364-366 (Dec. 2007), p. 98-103 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Using TracePro® Monte-Carlo ray-tracing simulations, this paper investigates theimproved light extraction efficiency (LEE) obtained by patterning the surface and/or substrate ofGaN LEDs with unique three-dimensional micro-cavity patterns. The simulations commence byconsidering the case of a sapphire-based GaN LED. The effects on the LEE of the micro-cavitydimensions, the absorption coefficient of the active layer, the point source location, and the chipdimensions are systematically examined. Subsequently, the LEE performance of the sapphire-basedGaN LED is compared with that of a thin-GaN LED for various surface texturing strategies. Ingeneral, the results show that patterning either the surface or the substrate of the LED structureprovides an effective improvement in the LEE of both the sapphire-based GaN LED and the thin-GaN LED. For both LED structures, the maximum LEE enhancement is obtained by patterning boththe upper surface of the LED and the substrate surface. However, the simulation results indicate thatthe improvement obtained in the LEE is the result primarily of pattering the upper surface of theLED
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/56/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.364-366.98.pdf
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Enhancement of the Optical Performances for the LED Backlight Systems with a Novel Dual Lens-Cap (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 364-366 (Dec. 2007), p. 132-137 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A novel dual-cone-shaped side-emitting lens cap for High Brightness Light EmittingDiodes (HB-LEDs) is proposed for improving brightness and high uniformity of the direct LEDbacklight Units (BLUs) for large-sized LCD-TVs. Combining the designed lens cap with red, greenand blue (RGB) chips on a Metal Core Printed Circuit Board (MCPCB), the LED module with theproposed cap is able to provide a compact white light source with unique features such as instantcolor variability and lower power usage, etc. The dual-cone-shaped of the proposed lens cap isdesigned to emit most of the light rays to the sides, only a small portion of light upward along theoptical axis of the lens, providing a uniform luminance distribution and the high brightness on thebacklight. In addition, a small reflective surface in semi-circular shape is designed and placed uponthe proposed LED module about 10mm, the surfaces of which are attached with reflective films toincrease the level of light mixing in the larger, global reflector optical box. With the structure of theLED module well designed, the LED backlight Module would be designed for the large-sized LCDTVusing the fewer number of LEDs to lead to lower power consumption. The results indeedidentify the attributes of the BLU, which make it possible to achieve excellent backlightperformance using a direct illumination approach from the light source of “Dual-Cone-Shaped Side-Emitting Lens Cap of LEDs.”
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/56/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.364-366.132.pdf
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Design of a Highly-Efficient Light Guide Plate for the Edge Lighting Backlight Module (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 364-366 (Dec. 2007), p. 128-131 
    Details
    ISSN: 1013-9826
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: This study develops a highly-efficient light-guide plate for edge lighting backlightmodule that has no optical films. The light guide plate is designed to control the angle of theincident rays to the top surface from light source, to get the highest uniformity of intensity for thinedge lighting backlight system applications. The micro-prisms of pyramidal shape on the topsurface can highly-efficient collimate with the light rays. Another micro-prism of v-cut shape on thebottom surface can reflect the incident light into the front direction and mixing the rays in the lightguideplate with the high uniformity. A novel design concept of the v-cut is the regular densityvaries of the cut in the LGP. The modeling simulation program, employing a Monte Carlo methodbased on TracePro software, has optimized the shape of the pyramidal micro-prisms on the topsurface and the density distribution condition of the v-cut micro-prisms on the bottom surface, alsothe multiple scattering characteristics. The two types of the micro-prisms at the top and bottomsurface can be highly recommended for the uniformity of the brightness via the optimal designprocess. Future work is warranted on improving the optical efficiency by using light-emittingdiodes as a light source. The backlight module will allow us to increase the optical efficiency and tolower the total cost in portable LCD applications. The study confirms that a uniformity ofbrightness can be achieved without using any optical films, resulting in a high uniformity of 84%
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/56/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.364-366.128.pdf
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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