An experimental study of yellow shift in injection-molded light guide plate

Min, In-Ki; Lee, Sung-Jun; Lee, Sung‐Hee; Kim, Jongsun; Yoon, Kyung Hoon

doi:10.1007/s13367-016-0019-2

Cited by 2 publications

(3 citation statements)

References 8 publications

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“…In a previous study, Min et al tried to explain the cause of the color shift in patterned LGP as the difference in residence time during the filling process of injection molding [13]. In the present study, the effect of the existence of the LGP's micropattern on the evaluation of transmittance and color shift was experimentally investigated.…”

Section: Discussionmentioning

confidence: 88%

“…Interest in color reproducibility has recently started to increase, as this factor allows implementing more natural images while competing with display technologies such as OLED. Min et al introduced the concept of color shift angle and studied the effect of molding processes related to melt temperature, injection speed, mold temperature, injection speed, and packing pressure on the color difference of an LGP and the direction and magnitude of the color shift [13]. However, they could not determine the contribution to the color shift made by the micropatterns, which were manufactured for uniform distribution of the light from the light source in the LGP to the entire LCD panel.…”

Section: Introductionmentioning

confidence: 99%

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An Experimental Study on Color Shift of Injection-Molded Mobile LGP Depending on Surface Micropattern

2020

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In the display industry, the LCD backlight unit (BLU) module is variously used in mobile phones, notebook computers, monitors, and TVs. The light guide plate (LGP), which is one of the core parts of a BLU, is getting bigger and thinner consistently. Conventional injection methods and injection processes like injection compression molding (ICM) are becoming more complex and harsher with high-speed injection at high mold and melt temperatures. These approaches lead to a change in physical properties and a decrease in optical properties such as yellowing and color shift in injection-molded parts. In the present study, an injection molding experiment was conducted to understand the effect of surface patterns and major injection process conditions like mold and melt temperatures on the color shift in injection-molded mobile LGP. Optical properties obtained by the direct and total transmittance and CIE xy chromaticity diagram for injection-molded mobile LGP were measured with a UV–visible spectrophotometer. From the measurement of patternless LGP, it was found that total or direct transmittance was not affected by molding process variables. It was also found that yellow shift, ΔE(xy), occurred as much as 0.00111 ± 0.00014, and a color shift angle, Θ(xy), of 43.05 ± 2.44° was recorded in CIE coordinates for all nine experimental cases. From the measurement of total transmittance of patterned LGP, ΔE(xy) and Θ(xx) were found to be almost the same as those of patternless LGP for the locations of low and medium density of the pattern for the LGP, T1 and T2. The measured data of direct transmittance of patterned LGP showed that additional yellow shift due to scattering caused by surface micropattern. Interestingly, Θ(xy) of patterned data remained 43.05 ± 2.44°, which was almost the same as that found in the case of patternless LGP.

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Section: Discussionmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

An Experimental Study on Color Shift of Injection-Molded Mobile LGP Depending on Surface Micropattern

2020

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“…These structures’ aspect ratios and pitches effectively controlled the degree of light confinement (>80%) along the lenticular corridors. Min et al [ 32 ] conducted a series of IM experiments to understand the distribution of yellowness in injection-molded LGPs and changes in optical properties under various IM conditions. Lee et al [ 33 ] synthesized micro hollow plate-type silica, which was applied as an optical structure to develop a light-diffusion material that satisfied requirements of high transmissibility and luminance.…”

Section: Introductionmentioning

confidence: 99%

Optimized Micro-Pattern Design and Fabrication of a Light Guide Plate Using Micro-Injection Molding

et al. 2021

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This study examined the uniformity of illuminance field distributions of light guide plates (LGPs). First, the authors designed microstructural patterns on the surface of an LGP. Then, a mold of the LGP with the optimal microstructural design was fabricated by a photolithography method. Micro-injection molding (μIM) was used to manufacture the molded LGPs. μIM technology can simultaneously manufacture large-sized wedge-shaped LGPs and micro-scale microstructures. Finally, illuminance values of the field distributions of the LGPs with various microstructures were obtained through optical field measurements. This study compared the illuminance field distributions of LGPs with various designs and structures, which included LGPs without and those with microstructure on the primary design and the optimal design. The average illuminance of the LGP with microstructures and the optimal design was roughly 196.1 cd/m2. Its average illuminance was 1.3 times that of the LGP without microstructures. This study also discusses illuminance field distributions of LGPs with microstructures that were influenced by various μIM process parameters. The mold temperature was found to be the most important processing parameter affecting the illuminance field distribution of molded LGPs fabricated by μIM. The molded LGP with microstructures and the optimal design had better uniformity than that with microstructures and the primary design and that without microstructures. The uniformity of the LGP with microstructures and the optimal design was roughly 86.4%. Its uniformity was nearly 1.65 times that of the LGP without microstructures. The optimized design and fabrication of LGPs with microstructure exhibited good uniformity of illuminance field distributions.

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An experimental study of yellow shift in injection-molded light guide plate

Cited by 2 publications

References 8 publications

An Experimental Study on Color Shift of Injection-Molded Mobile LGP Depending on Surface Micropattern

An Experimental Study on Color Shift of Injection-Molded Mobile LGP Depending on Surface Micropattern

Optimized Micro-Pattern Design and Fabrication of a Light Guide Plate Using Micro-Injection Molding

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