Papers by Author: Chi Feng Chen

Abstract: A light emitting diode (LED) light guide bar based on concave V-grooves is investigated by using optical simulation software to control the distribution of illumination angle. The structure parameters of V-groove and the distribution of micro-prism are considered. It is found that the illumination angle of LED light guide bar is most concentrated within ±35 degrees.

Abstract: A novel optical sheet with double-layer microstructures is proposed to improve the brightness uniformity and optical efficiency in the LED direct-lit backlight module. By means of 2D ray-tracing program design and commercial optical software simulation, we enhance the brightness uniformity from 45.3% with traditional planar diffuser to 82.7% with new optical sheet, and the average brightness is promoted about 10.9% in the same frame of backlight module which internal thickness is only 13mm. Thus, this novel optical sheet with microstructures design is useful for a slim LED direct-lit backlight module.

Abstract: This study discusses optimization of the adiabatic optical directional coupler (AODC) based on sin-square weighting functions (SSF) for waveguide structure. The objective of the work includes the define coupler of theory ranges, low crosstalk and short coupler length, respectively. When the crosstalk is demanded to be smaller than -35 dB, the coupler length for SSF is 2 b0 λ (minimum local beat length). Definitely SSF which is proposed can obtain a better result after the structural design.

Abstract: The optimization of the directly-under-light type backlight module structure for brightness uniformity is investigated. All structure parameters of the 32-inch LCD-TV backlight module are chosen by the ray-tracing method for the optimal brightness uniformity. It is shown that the brightness uniformity without optical sheets can be made as high as 87.3%.