• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.1
• /
• pp.79-84
• /
• 2003

A light guide panel is an element of the LCD backlight module that is often used for the display of compact electronic devices. In this study, a laser marking system is proposed to fabricate light guide panel, which can replace other manufacturing methods such as silk printing, stamping, or v-cutting methods. The objective of this research is to evaluate the process parameters of the laser marking system. Light guide patterns were marked with a 50W $CO_2$ laser (CW) to understand the effects of average power and scanning speed on the geometry and quality of groove pattern. The width of the fabricated grooves increases with increasing laser power and decreasing scan speed. In order to analyze surface characteristics and optical properties (luminance, uniformity), SEM photography and BM7 (luminance measuring system) were used. As a result, the optimal conditions of the process parameters were determined.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.693-696
• /
• 2009

The ray-tracing technique was used to optimize the light guide plate for the purpose of improving the on-axis luminance on the edge-lit backlights. One-dimensional prisms and engraved V-shaped patterns were applied to the upper and the lower surfaces of the light guide plate, respectively. By optimizing the apex angles of these micro-structures, as well as the shape of the reverseprism film put over the light guide plate, highly-collimated light-output distribution could be obtained on the backlight, which may contribute to the development of mobile LCD's with low power consumption.

• Proceedings of the Optical Society of Korea Conference
• /
• 2007.07a
• /
• pp.15-16
• /
• 2007

A design of a light coupler between a LED and a very thin light guide (0.2mm thickness) is presented. Due to the light guide's very thin thickness, conventional light couplings between LEDs and light guides do not provide enough coupling efficiency. We investigate two different coupling methods: side coupling using a complex-shaped lens and bottom coupling using a grating. This paper presents a draft design of the first approach which couples light from 0.4mm LED to 0.2mm light guide without significant losses.

• Journal of Radiation Protection and Research
• /
• v.41 no.3
• /
• pp.282-285
• /
• 2016

Background: To optimize the photon transmission efficiency of light guides used in scintillation detectors, LightTools code, which can construct and track light, was used to analyze photon transmission effectiveness with respect to light guides thickness. Materials and Methods: This analysis was carried out using the commercial light guide, N-BK 7 Optical Glass by SCHOTT, as a model for this study. The luminous exitance characteristic of the LYSO scintillator was used to analyze the photon transmission effectiveness according to the thickness of the light guide. Results and Discussion: The results of the simulations showed the effectiveness of the photon transmission according to the thickness of the light guide, which was found to be distributed from 13.38% to 33.57%. In addition, the photon transmission efficiency was found to be the highest for light guides of 4 mm of thickness and a receiving angle of $49^{\circ}$. Conclusion: Through such simulations, it is confirmed that photon transmission efficiency depends on light guide thickness and subsequent changes in the internal angle of reflection. The aim is to produce an actual light guide based on these results and to evaluate its performance.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.1519-1522
• /
• 2009

We describe a 32" liquid-crystal display (LCD) with multi-touch sensing capability by integrating IR detector arrays onto the LED backlight plate. A transparent light guide is placed in front of the display screen, with IR LEDs disposed at its edges and emitting IR light into the light guide, the light is trapped by total internal reflection within the light guide to be as touch-sensing light. A physical contact with the acrylic plate surface will stimulate some trapped light to be escaped from the light guide and pass through LCD panel to be detected by the IR detectors. The touch-sensing LCD with this configuration can locate simultaneous multiple touche points on the touchable surface.

• Korean Journal of Optics and Photonics
• /
• v.31 no.4
• /
• pp.176-182
• /
• 2020

The possibility of replacing the condensing-prism film used in conventional backlight units with a light-guide plate engraved with a submicrometer-periodic diffraction grating was investigated. The optimal period for the diffraction grating was determined through simulation and experiment, and the transmission-mode efficiency of the diffraction grating was calculated in terms of the polar angle and azimuthal angle of the incident light. In addition, the effects of the two methods of optimizing the polar angle and the directional angle were compared by simulation, by suggesting the shape and configuration of the light-guide plate, so that more light could be extracted by diffraction. By using a ray-tracing program, the luminance angular distribution of the light-guide plate engraved with the diffraction grating was calculated and compared to the luminance angular distribution for each actual prototype.

• Transactions of Materials Processing
• /
• v.21 no.2
• /
• pp.126-130
• /
• 2012

Accurate optical texturing of light guide plate over the entire surface area is an important technical issue in LCD TV industry. Injection molding process has the potential to produce large light guide plates having highly efficient optical textures such as micro-prism array. This study is focused on the effect of the degree of replication of the micro texture of the 40" injection molded light guide plates on the overall optical performance of the display panel. Measured replication ratios of the micro-textures formed with three different types of injection molding process were considered in the modeling of prismatic micro segment array. Optical simulation was conducted and results were discussed.

• 제어로봇시스템학회:학술대회논문집
• /
• 2000.10a
• /
• pp.162-162
• /
• 2000

We describe a new optical-type guide sensor for AGV. It is robust the disturbance of the light. The developed optical-type guide sensor is very useful in the clean room environment where the light disturbance is very critical through the hole on the surface of the floor.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2003.04a
• /
• pp.73-77
• /
• 2003

The backlight unit(BLU) is used as a light source of TFT liquid-crystalline-display (TFT-LCD) module. In this backlight unit, one of important components is the light guide, which is usually made of transparent polymers. Currently the screen-printing method is mainly used for the light guide as a manufacturing process. However, it has limitation to the flexibility of three-dimensional optical design. In the present paper a new alternative manufacturing method for the light guide with low-cost is proposed. This manufacturing method is named as direct surface forming (DSF), which is very similar to the well-known hot embossing except for partial contact between mold and substrate. The results of this new manufacturing method are presented in terms of processing condition, dimensional accuracy, productivity, etc.

• Transactions of Materials Processing
• /
• v.11 no.4
• /
• pp.341-348
• /
• 2002

For the light guide plate of the TFT-LCD, there have been increasing demands for higher brightness, thin and light-weight design, and lower power consumption. To meet these demands, a micro-prism-type frontlight that integrates a prismatic sheet and a light-guiding plate has been developed. In this paper, the influences of processing conditions on the brightness were studied lot the injection molding of the light guide plate. Based on the experiment with an actual mold, the design of experiments and the neural network theory were used lot choosing the optimal processing parameters to increase the brightness and the uniformity. The verification experiment also showed that the brightness and the uniformity were increased dramatically with the chosen processing conditions.