The Study on the influence of V-Cut design to the Brightness Distribution of BLM

• Main Authors: Bo-Hua Lin, 林伯樺
• Other Authors: Shih-Ming Wang
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/64625944536010113557

碩士 === 中原大學 === 機械工程研究所 === 94 === The effect of the vertex angle of V-cut and the pitch distance between V-cuts in the light incident surface of light guide plate (LGP) on the brightness performance of the back light module (BLU) is studied. A 2.2-inch back light module is established and simulated this model by the aid of Specter software. To simplify the LGP condition, the dot pattern is fixed in the reflection surface. The criterion for this selective dot pattern is that the 9-point brightness uniformity of BLU is higher than 80%. The Specter has a light trace capability on the simulated BLU. The light is emitted from the LED, passes into incident V-cut surface and transports through whole LGP by internal reflection repeatedly. The light leaves the LGP when it hits the irregular surface and breaks the internal reflection condition. The light trace phenomena are observed by Specter to treat the light in the LGP as an object traveling history. A special function, called observer, is established in the active area of the LGP to monitor the variation of the central brightness, average brightness, uniformity and maximum brightness with the different V-cut geometric features. After evaluating the difference among the simulated results, we select an optimal result and practice a mold for comparison purpose. The simulated error converged limit of this study is set as 6.8% to reduce the calculating time. The LED lumen is adjusted to fit the gap between the experimental data and simulated result. After adjustment, the gaps of the central, average brightness and uniformity are 1.2%, 0.5% and 7.6% respectively. However, the maximum brightness has 51.4% gap and occurs the region neighboring to LED. This significant difference may come from singularity calculation when the calculated area is close to LED. The optimal V-cut vertex angle obtained is 120o and the pitch distance is 0.2mm under this studied condition.