Design of a brightness-enhancement-film-adaptive freeform lens to enhance overall performance in direct-lit light-emitting diode backlighting

Abstract

In this study, a brightness-enhancement-film- (BEF) adaptive method is proposed to design freeform lenses for enhancing brightness performance in a direct-lit light-emitting diode (LED) backlight system. A detailed design algorithm is presented based on the analysis of the output optical properties of the BEF. By introducing a constriction factor, we can control the light intensity distribution curve at will to adapt to the characteristics of the BEF and make more light transmit through the BEF. Compared with an LED backlight system without a freeform lens, the BEF-adaptive lens method can improve axial luminance by 20.67% and output efficiency by 6.02%.

Improvement of Spatial Luminance Uniformity in Emitted Light from Flexible Backlight Using Notch-Type Variable Light Distribution Films

“…Light from the LGP is directed in a normal direction by two crossed-prism films attached to the diffusing film. [4], [6]. The edge-type BLU has approximately a cone shape solid angle for emergent light [4].…”

“…Figure 3 shows the effect of the prism films on the angular luminance distribution; the luminance along the normal direction is especially strong, leading to effective light utilization efficiency when viewed from above. Notably, the optical characteristics of the prism film are maintained even in films in a curved state [6]. However, the most commonly used flexible backlight shows a poor luminance distribution in a curved state, due to the characteristics of the prism film.…”

“…Under these conditions, the notch angle α and cutting pitch p were determined by Eqs. (6) and 4, respectively. The incident light on the film is represented by θ = 0 • .…”

LED packaging for high light quality: Status and perspectives

“…对于阵列LED模块. Zhang和 Lee [130] 通过在基板上加工微槽来限制封装胶的流动, 从而得到和基板之间具有较大接触角的晶圆级荧光 粉涂覆方法; Yu等人 [131] [117,118,134,135] . 针对于扩展光源, Munon等人 [137] 和Benitez等人 [138] 于2004年提出多曲面同时设计法 ( [154] .…”

Developments for lighting applications by using prismatic film

“…In addition to areas such as lighting in architecture, the automotive illumination and display technology has undergone considerable technological advances in recent decades such as the use of LEDs which represents an industry breakthrough in lighting technology and is rapidly becoming the most important innovative technologies around the world in the lighting community [13,14,15]. This paper show several developments related to the performance of prismatic sheets.…”