• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.2
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• pp.133-133
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• 1999

Average illuminance and luminance can be calculated by graphical methods to a certain extent but to calculate for a wide place a suitable software is needed. Softwares suitable for this purpose have been already developed in foreign nations, but the appropriate softwares for domestic use have not been developed. Therefore a program is developed which is executable in Hangul Windows. The softwares LAPRoad, is developed to calculate luminance and illuminance distribution of road surface, as well as average luminance and illuminance, overall uniformity, longitudinal uniformity, threshold increment veilling luminance and glare. And an apparatus that measures road surface reflection properties is developed. Because the road surface reflection properties is very important in luminance calculation, then concrete road surface reflection properties were measured.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.5
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• pp.382-388
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• 2016

When Flat Panel Display (FPD) is made with backlight module, such as LED TV, it inherently suffers from the non-uniform backlight luminance problem that results in un-even brightness distribution throughout the TV screen. If the luminance of each pixel location of a TV screen as a function of the driving voltage can be measured, it can be used to compensate the non-uniformity of the backlight module. We use a carefully calibrated imaging system to take pictures of a TV screen at different levels of brightness and generate the compensation functions for the driving circuitry to correct the luminance level at each pixel location. Making use of the fact that the luminance of the screen is normally brightest at around the center of the screen and gradually decreases toward the border of the screen, the luminance of the whole TV screen is approximated by a mathematical function of the pixel locations. The parameters of the function are computed in the least square sense by the values of both the pixel luminance sent from the driving circuit and the grayscale value measured from the image taken by the imaging system. To justify the correction system, a simple second order polynomial function is used to approximate the luminance across the screen. When the driving circuit voltage is corrected according to the measured function, the variance of the screen luminance is reduced to one tenth of the one measured from the un-corrected TV screen.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1487-1490
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• 2005

This study proposes a controller with the techniqu e of voltage -compensated driver for producing grayscaled pictures on passive matrix organic light emitting diodes (PMOLEDs) panels; especially, the controller overcomes the problem of luminance nonuniformity on displaying pictures. Because the controller is a voltage type driver, the output impedance of the driver is much less than that of the current-type driver. Hence, the controller provides a better electron-optical response than those of traditional current drivers. An area compensated look-up table (ACLUT) is designed in data feeding paths for removing luminance non-uniformity; thus, the proposed controller provides nearly 95% luminance uniformity.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.227-230
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• 2004

Phosphor layers on rear plate of PDP were formed via osmosis coating process in an attempt to improve thickness uniformity of phosphor layer and eventually to enhance luminance and its efficiency of plasma display panel. The phosphor layers were formed uniformly not only on the sidewalls of barrier ribs but also on the dielectric layer of rear plate by the process. The processing parameters affecting the thickness uniformity of the phosphor layer formed by the osmotic coating process were investigated.

• Journal of the Optical Society of Korea
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• v.11 no.3
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• pp.118-123
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• 2007

The emitting structure of multi-channel-type flat fluorescent lamps (FFLs) combined by a lenticular-lens-patterned diffuser plate was optimized by the ray tracing technique. The optimal parameters such as the distance between the channels of the FFL and the distance between the FFL and the diffuser plate were suggested from the viewpoint of the luminance uniformity. The best luminance uniformity, which was higher than 90%, was obtained at the channel distance of 4 mm and the distance of 12.5 mm between the FFL and the patterned diffuser plate.

• Transactions on Electrical and Electronic Materials
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• v.8 no.6
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• pp.268-273
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• 2007

In this study, It was studied about the luminance characteristics of 17 inch direct-type back light using EEFL(external electrode fluorescent lamp) and CCFL(cold cathode fluorescent lamp). The EEFL has a long life time because the electrode is installed outside of lamp. And it is produced in lower price than conventional CCFL. Moreover, it does not need process of installing internal electrode. However, the EEFL technology has several problems such as difficulty of designing driving inverter and preventing this phenomenon along the skin of lamps. We suggested two types of backlight unit for LCD TV application using the EEFL and the CCFL. We found optimized optical design parameters. We set the optical variation parameters such as lamp height, lamp distance, total thickness, and angles of inner walls. We achieved 7580 nits of center luminance, 82% of luminance uniformity by using 20 lamps of the EEFL and 7297 nits of center luminance, 78% of luminance uniformity by using 16 lamps of the CCFL.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.12a
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• pp.35-38
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• 2006

As a display becomes large recently, Acquisition of high luminance and Luminance uniformity is becoming difficult in the existing CCFL or EEFL backlight system. So, study for a performance enhancement has enforced. but lamp development of flat type is asked for high luminance and a luminance uniformity security in of LCD and area anger trend ultimately. In this paper, we changed a tip shape of an electrode for production by the most suitable LCD backlight surface light source, and confirmed discharge characteristic along discharge gas pressure and voltage, and confirmed electric field distribution and discharge energy characteristic through a Maxwell 2D simulation. Therefore the discharge firing voltage characteristic showed a low characteristic than a rectangular type and round type in case of electrode which used tip of a triangle type, and displayed a discharge electric current as a same voltage was low.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.12
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• pp.15-21
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• 2015

We proposed 50W-LED modules of using Heat-pipe and Stack-fin and produced LED modules was evaluated heat dissipation characteristics with comparison of the conventional die-casting type. It verified the application of products by applying it to 150W-LED road luminaires through simulation. The LED module was measures aimed design temperature of the Stack-fin and showed 26% upward heat dissipation effect than a conventional die-casting type. The luminous efficacy of 150W-LED road luminaires using this LED module reached over 112lm/W, and the simulation results showed average of horizontal luminance, overall luminance uniformity($U_O$) and lane luminance uniformity($U_I$) that is suitable for five-lane road with the KS standards.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.1
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• pp.114-119
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• 2011

There is a limit to technology of improving luminous intensity uniformity and glare, known as a weakness of existing LED lamp. Because of Using many LED, LED lamp not only waste energy but have bad effect on efficiency. Our goal is to develop security lights solution which is contented with suitable area in KS(Korean Industrial Standards) and to remove glare by combining asphere in optical system with different concept. To improve luminous intensity uniformity, a reflect mirror system was used after an aspheric optical system design for this study. We made a mirror and measured it after analysing luminance changes depend on aspheric shapes with simulation program to see if aspheric shapes effect luminance distribution. We made progress to find problems and improve them by comparing measured data and analysed data. This result of the study will contribute to industry of LED lighting through developing solution of emotional illumination of LED security lights by knowing the importance of reflectivity with this study and improving luminous intensity uniformity with solving the problem.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.2
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• pp.1-6
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• 1999

Average illuminaoce and luminance can be calculated by grarhical rrethods to a certain extent, but to calculate for a wide place, a suitable software is needed. Softwares suitable for this purpose have been already developed in foreign nations, but the appropiate softwares for domestic use have not been developed 1berefore a program is develqJed which is executable in Hangul Windows. The softwares LAPRoad, is develqJed to calculate luminaoce and illuminance distribution of road surlace, as well as average luminance and illuminance, overall uniformity, longitudinal uniformity, threshold increement, veilling luminance, and glare. And an apparatus that measures road surface reflection properties is developed. Because the road surlace reflection properties is very important in luminance calculation, then concrete road surlace reflection properties were measered.asered.