Effects of adding injection–compression to rapid heat cycle molding on the structure of a light guide plate

Hong, Seok-Kwan; Min, In-Ki; Yoon, Kyung Hoon; Kang, Jeong-Jin

doi:10.1088/0960-1317/24/1/015009

Cited by 24 publications

(18 citation statements)

References 29 publications

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“…To improve the transcription quality and uniformity of the microstructures, local mold heating (LMH) during the micro‐injection molding has been proposed . The mold temperature is maintained near the glass transition temperature ( T g ) of the plastic using LMH.…”

Section: Introductionmentioning

confidence: 99%

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Numerical and experimental investigation of plastic injection molding of micro‐engineered surfaces

Lee

Park

2017

Polymer Engineering & Sci

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We carried out experimental and numerical investigations into the effects of injection‐molding parameters on the transcription quality and uniformity of micro‐pillar arrays. For the experiment, we used a precise metallic mold insert, which was shaped like an inverted micro‐pillar array. This was fabricated using UV‐photolithography and a nickel electroforming process. With the mold insert, the effects of the distance from gate and uniformity on the transcription quality could be investigated experimentally by varying the main processing parameters, such as flow rate, polymer melt temperature, and mold wall temperature. The results of the injection molding experiment indicated that increasing the three processing parameters improved the transcription quality of micro‐pillar arrays. In numerical investigation, we used the interpolated domain decomposition method. This was based on 2.5D and 3D simulations, and was used to effectively solve the filling behavior of the polymer melt inside the mold which contains multi‐scale cavities. Numerical results revealed that the transcription quality was significantly affected by the mold wall temperature. Based on the experimental and numerical investigations, the local mold heating (LMH) technique for the high mold wall temperature was employed to enhance the replicability of the micro‐pillar array. The result of injection molding with LMH showed that the transcription quality and uniformity were considerably improved. These numerical and experimental results provide insights into the foundations of the field of injection molding of plastic micro‐engineered surfaces. POLYM. ENG. SCI., 58:E73–E81, 2018. © 2017 Society of Plastics Engineers

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Section: Introductionmentioning

confidence: 99%

“…Thus, the microstructures can be faithfully replicated along with the BP. In addition, injection molding with LMH attenuates unexpected defects, such as the weld line, warpage, and birefringence, by diminishing the frozen layer or molecular orientation .…”

Section: Introductionmentioning

confidence: 99%

Numerical and experimental investigation of plastic injection molding of micro‐engineered surfaces

Lee

Park

2017

Polymer Engineering & Sci

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“…Then, the melting polymer is injected into the microstructured mold under relatively high pressure. In order to get better replication results, vacuum-assisted injection molding, injection compression molding, and many other kinds of injection molding methods were developed [ 130 , 131 ]. Fourthly, after the melting polymer is fully filled into the microstructured mold, it should be cooled below the solidification temperature of the polymer within mold for structure definition.…”

Section: Common Manufacturing Methods For Polymer-based Microfluidmentioning

confidence: 99%

Microfluidic-Based Single-Cell Study: Current Status and Future Perspective

Zhu

Huang

et al. 2018

Molecules

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Investigation of cell behavior under different environments and manual operations can give information in specific cellular processes. Among all cell-based analysis, single-cell study occupies a peculiar position, while it can avoid the interaction effect within cell groups and provide more precise information. Microfluidic devices have played an increasingly important role in the field of single-cell study owing to their advantages: high efficiency, easy operation, and low cost. In this review, the applications of polymer-based microfluidics on cell manipulation, cell treatment, and cell analysis at single-cell level are detailed summarized. Moreover, three mainly types of manufacturing methods, i.e., replication, photodefining, and soft lithography methods for polymer-based microfluidics are also discussed.

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“…Yokoi et al made a vacuum in the mold and observed the filling process while conducting a molding experiment to increase the transferability of the V-groove pattern in the ultrahigh-speed injection molding process [3]. In addition, Hong et al conducted a comparative study on the transferability and birefringence distribution of the pattern through 7-inch LGP molding using the rapid injection-compression molding (RICM) process that combines the injection-compression process and rapid mold heating [4]. However, previous studies related to LGP mainly focused on optimization of optical patterns to increase luminance and uniformity and enhance the transcriptional properties of micropatterns during molding [5][6][7][8][9][10][11][12].…”

Section: Color Chromaticitymentioning

confidence: 99%

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

2020

Self Cite

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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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Effects of adding injection–compression to rapid heat cycle molding on the structure of a light guide plate

Cited by 24 publications

References 29 publications

Numerical and experimental investigation of plastic injection molding of micro‐engineered surfaces

Numerical and experimental investigation of plastic injection molding of micro‐engineered surfaces

Microfluidic-Based Single-Cell Study: Current Status and Future Perspective

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

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