P-184: Novel Diffuser for LCD Backlight Application

Guo, Huang-Chen; Yang, Chorng-Horng; Lü, Ying; Lai, Pong; Tyan, Wann‐Diing; Chu, Chang-Sheng

doi:10.1889/1.2036504

Cited by 5 publications

(7 citation statements)

References 6 publications

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“…This indicates that the birefringence of the fabricated LGP is negligible. We inscribed fine prismatic line patterns on the lower surface of the LGP by CO 2 laser ablation, [17][18][19][20][21][22][23] which is more effective for maintaining the polarization state of light within the LGP, as reported in our preliminary study. 40) In addition, this patterning technology enables fast fabrication for various patterns designs, and it is low-cost as compared with other commercial-scale LGP patterning technologies because it does not require a mold to form light extraction patterns in the LGP.…”

Section: Design and Experimental Resultsmentioning

confidence: 99%

“…1. Here, we used a polymer light guide plate (LGP) with fine prismatic line patterns fabricated by CO 2 laser ablation [17][18][19][20][21][22][23] and a Ag bottom reflector to enhance the specular reflection. We used a reflective polarizer 24,25) instead of an absorptive polarizer as the polarizing element for the light source to generate linearly polarized incident light.…”

Section: Configuration and Evaluationmentioning

confidence: 99%

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Polarized light-emitting backlight unit using a retardation film for improving light efficiency in a twisted nematic mode liquid crystal module

Moon

Lee

et al. 2014

Jpn. J. Appl. Phys.

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We propose and demonstrate a new polarized backlight unit (BLU) configuration to enhance light transmission in a twisted nematic (TN) mode liquid crystal (LC) panel. By adding an optimized phase retardation film (PRF) to the BLU, we efficiently controlled the polarization state of the light from the light guide plate (LGP), enabling it to be aligned along the transmission axis of the bottom polarizer of the LC panel. We designed and fabricated a 7 in. edge-lit BLU with a PRF. To obtain a uniform positional distribution in both light intensity and degree of polarization (DOP), the LGP was optimized with linear groove patterns. To maximize BLU light transmission through the bottom polarizer in a TN-mode LC panel, the slow axis of the PRF was aligned at 22.5° with respect to the LED array axis. We improved the transmittance from 45 to 72%.

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Section: Design and Experimental Resultsmentioning

confidence: 99%

Section: Configuration and Evaluationmentioning

confidence: 99%

Polarized light-emitting backlight unit using a retardation film for improving light efficiency in a twisted nematic mode liquid crystal module

Moon

Lee

et al. 2014

Jpn. J. Appl. Phys.

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“…Here, we used a polarized BLU configuration similar to that used in our previous study 20) but with a new LRF on the LGP. The BLU configuration consisted of a polymer LGP with fine prismatic line patterns produced by CO 2 laser ablation [21][22][23][24][25][26][27] on its back surface. The LGP had prism patterns whose interval ranged from 280 to 600 µm to ensure a uniform luminance, as reported in our previous study.…”

Section: Configuration and Evaluationmentioning

confidence: 99%

Polarized backlight unit using a polarization-preserving light-redirecting film for improving luminance gain

Moon¹,

Lee²,

Oh³

2015

Jpn. J. Appl. Phys.

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We proposed and demonstrated a polarized backlight unit (BLU) configuration with a new light-redirecting film (LRF) to improve the luminance gain and light transmittance in liquid crystal displays. We combined a very low birefringence triacetyl cellulose (TAC) base layer with UV-cured prismatic patterns in a mass-producible process to demonstrate a polarization-preserving LRF. Detailed analyses of the states of polarization (SOP) through the LRF were reported. We also fabricated a 7-in. edge-lit BLU using the new LRF. We found that the light directing capability of the new LRF was equivalent to that of a conventional prism film whose base layer was a poly(ethylene terephthalate) (PET) film, and that the new LRF successfully suppressed random polarization changes of the transmitted light. Utilizing these new advantages, we obtained 68% transmittance through the polarizer over the BLU with the new LRF, which was about 1.3-fold that for the BLU with the conventional prism film (54%). We also obtained 127% luminance gain using the new LRF, which was equivalent to that of the conventional prism film. Here, the luminance gain is referred to as the amount of increase in luminance on the surface normal of the light-guiding plate without any film.

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“…A conventional CMO 27-inch LCD-TV uses 14 CCFLs and the pitch is 23.8mm. The brightness uniformity was shown as figure (5). From the CCD picture, not only CCD analysis system but also human eyes cannot find any bad uniformity from brightness difference.…”

Section: / C-c Humentioning

confidence: 99%

“…Reducing the CCFL number in normal backlight unit will decrease the brightness uniformity. There are several approaches to help designer get better backlight uniformity, however it does need effort to modify the component manufacture processes [1][2][3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%