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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The Effect of the Integrated Design of Light Guide and Diffusion Structures on the Uniformity of the Backlight Module

Lin, Chih-Hsing 06 July 2007 (has links)
Recently, the novel development of light guide is V-cut light guide which integrate the micro-prisms on the top and bottom surface of the light guide. Although the V-cut light guide can use the energy of light source efficiently, its uniformity is lower than the traditional scattering dots light guide. Therefore, the purpose of this study is to improve the low uniformity phenomenon of V-cut light guide. First, this study designs three micro-structures on the bottom surface of light guide, and analyzes the influences of shape and geometric parameters of each micro-structure on the luminous flux enhancement. Then, on the top surface of light guide, the micro-lens are modeled which includes the scattering characteristic of diffuser in order to improve the backlight uniformity. It can achieve the effect of diffuser does through the design of scattering micro-lens, so it can save the cost of diffuser. Finally, the integrated design of 7 inches light guide and diffusion structures was simulated by using commercial software LightTools, and the result shows that the backlight uniformity can achieve 90.6%.
2

Design of the Light Guide Plate with Stepped Micro Structures

Lien, Yen-Po 26 January 2008 (has links)
In this thesis, we utilized CCFL as the sidelight of backlight module. At the same time, we designed many um-size and 45 degree stepped microstructures on the bottom of LGP to reach the goal of uniform plane light due to its diffraction effect. Then mostly incident light can be induced to the ejected surface by once of total reflection. This way can avoid light energy being wasted, which always happens in traditional LGP design because of several times of diffraction and reflection occurred in front of light being ejected out of LGP. Moreover, stepped microstructures LGP combines the functions of reflector, diffuser, and prism film, so it can lower material cost. Relating to geometrical optics, we simulated our design with TracePro software to verify the effect we expect; relating to wave motion theory, we verified it by Definite Difference Method and programming with Matlab language. At last, we made samples to verify the above simulations and theories.
3

Analysis of Film Waving in LCD Backlight Module

Su, Pei-chun 03 September 2005 (has links)
Liquid crystal display is the most valuable and universal produce of the electric monitor presently. Due to the non-luminant display device, it must use the light source of the backlight module to reach display effect . In backlight module field , it is focus on the even distribution of the light source and the perfect appearance without any defect occurrence. Besides, the existence of film waving will cause the bad phenomenon .To improve and avoid the defect occurrence,through the workable analysis experiment can find the real element progressively . In the experiment , we will focus on the characteristic of the film material and each material¡¦s dimension which analyze by BM-7 and Nieo LCD analyzer,etc. According to angle orientation.From the result,we can realize that the stronger structure material and larger heat capacity of Diffusion Film, will decrease the expand and shrink for temperature , and film waving caused by temperature changing, which may resolve the film waving effectively.
4

Thermal Deformation Effects on Characteristics of LCD Backlight Module

Tseng, Yu-Ming 09 September 2005 (has links)
The liquid crystal displays itself has a lot of advantages, such as thin thickness, slight weight and high brightness, etc. It is an important target for many engineers to develop the high brightness, uniformity, low power consumption and thin backlight module. Due to the temperature raising of the cold cathode fluorescence lamp (CCFL) in a backlight module of a LCD under long-term lighting state, the micro-optic-structure will deform and cause an uneven luminance phenomenon. In this research, was provided a method of creating a model with thermal deformation and how to draw this model by using PRO/EINGINEER. Then, one can transform the model into the optical software, ASAP, to make optical analysis. Finally, the thermal module can be studied.
5

SMD Type Metallic Reflection Cup LED Component on the Application of Backlight Module

Wang, Hui-chi 17 July 2009 (has links)
Nowadays, using the LED as backlight module's light source becomes generalization gradually, and the application of LED light source develops from the liquid crystal display to the liquid crystal TV. However, thermal dissipative problem of LED component is still an important issue to study presently, since it can affect the service lives of LED and LCD seriously. In order to increase the luminous energy of the LED component, one need to increase the supply of electric power and it will cause the increment of thermal dissipative problem of the LED component also. Therefore, by considering the LED components as the light source of the backlight module , the purpose of this study is to reduce number of the required LED components in order to decrease the thermal dissipative problem of LEDs, and maintain the luminous and uniformity of the backlight module simultaneously. A new packaging for LED, named SMD type metallic reflection cup LED component, was proposed in this study. The new LED package not only has a better thermal dissipative property, but also can control its radiation property by changing the angle of its reflection cup. So, the proposed LED package can be applied for different purposes. By applying the proposed LED components as the light source of a backlight module, under the condition of same illumination, it can be shown that the required number of LED components can be decreased tremendously and so the thermal dissipative problem can be decreased too. Also, the numerical simulated results showed that by choosing the suitable angle of the reflection cup, the uniformity of the backlight module can be improved. Besides, this study proposed a modified method for assessing the uniformity of a backlight module. The simulated results showed that the proposed method can assess the uniformity of a backlight module more suitable than the traditional nine points measurement method can do.
6

The Studying about Major Factors of Manufacture in LED Backlight Module

Chen, Chun-Ho 17 June 2010 (has links)
In the LCD display products source section LED light display product is OK to replace the traditional CCFL light display products, especially in the NB computer and computer monitor are almost over two to three years CCFL products will be completely out of the market. The LCD itself does not glow and need another light source to support it. Backlight module can provide light source to LCD display product. In the early the light source of backlight module is CCFL. But LED light source is going to replace CCFL from 2007. Most of all new developments in the field of the NB computer backlight module changes light source from CCFL to LED. Even the computer monitor light source is starting to use LED too. The development technologies and production quality of the LED backlight module are significant challenges in LED backlight module factory. The purpose of this study was to identify development technologies and production technologies factors of bottlenecks, and finding a solution. And can provide some help to LED backlight module industry terms. This study selects ' 8D process ' to be analysis model. And collect 5 backlight module factories development experience and production status data. Hope these data through 8D analysis process can find the major related factors of development technologies and production technologies. In-depth research, look forward to finding out the production technologies relevant factors oppression ' technical specification ' production. This study is expected to be able to find some effect LED backlight module process yield factor, then apply the stratification out product issues and process issues, this study is intended for process issue do take an in-depth look at the problem and solution, but about product issue will be' design solutions ' way to describe. I believe this research can help LED backlight module industry to reduce production cost and improve the development speed.
7

Optimization of Processing Parameters for LED with Surface Mount Technology

Tseng, Kuan-ling 03 August 2010 (has links)
In July 2006, the legislation of RoHS(The Restriction of the use of the Hazardous Substances in Electrical and Electronic Equipment) is fully implemented in EU. Although the major industries have response and preparedness for lead-free products, but they have no complete solution for using lead-free solder paste to replacing tin-lead solder paste. Therefore, two major issues arose in the surface mount process which are the cost increasing and the reliability decreasing of electronic products caused by higher reflow temperature. In addition to these two issue, surface mount of LED is also faced with the problem of attenuating of light intensity of LED due to the increasing of reflow temperature. After years, the companies of solder paste product and surface mount technology accumulate a lot of processing experience and they have certain yield on reflow process of LED. In order to keep competitiveness and market share, the know-how is treated as confidential. By working with about 10 professional surface mount manufacturers, it is interesting to note that solder paste and oven temperature curve used by each manufacturer are not actually the same. By adopting the experiences of cooperation with several professional surface mount manufacturers through experiments, the purpose of this thesis is to find the optimal reflow process parameters such that the light intensity loss of the LED caused by lead-free reflow process can be reduced as much as possible. By using Taguchi method and the executed experiments , the optimal parameter-combination have found efficiently from the four parameters: the peak of reflow temperature, the peak temperature of residence time, the brand of solder and the pre-baking time of LED. The results showed that the peak reflow temperature has the greatest influence among the selected four parameters and the following is the peak temperature residence time. The light intensity loss can be reduced up to 4-9% by adopting the obtained optimal parameters.
8

Backlight module industry electronic supply chain management model -- A case study of a company

Hsieh, Ming-jiuan 17 July 2007 (has links)
Supply Chain Management involves the cross-organizational interaction and integration, sharing of resources and information, supply chain to optimize the overall goal. In this process there are many interference performance of the uncertainty factors, instead of the uncertainty generated, the extent of the supply chain members unable to obtain the information needed for decision-making. The lack of transparency of information, it will cause the supply chain every member of inventory cost and increase productivity without the use of efficiency, reduce the competitiveness of enterprises. Based on the study that through information sharing, process reengineering and the establishment of performance appraisal system can be an effective supply chain operation of the uncertainty facing the problems and improve the performance of the supply chain and business performance. The results showed that backlight module manufacturing industries belong to industry, labor-intensive, highly customized products. short product life cycles and frequent changes in the demand for the supply chain characteristics, its own high demand uncertainty, through with the customer demand for information-sharing and coordination process, which can effectively reduce demand uncertainty, Implement process improvement orders In cross-organizational coordination mechanism, through information sharing will help the supply chain, reduce the bullwhip effect on the supply chain significantly, and its customers and share the risks and profit sharing. In addition, the synergistic operation of the supply chain framework of analysis, cooperative enterprise in pursuit of enterprises operating information Seamlessly and the operation of the synchronization overall cooperation can play the largest comprehensive Synergy.
9

A Study on Reducing LED Amount Used in 14 Inches LCD Back Light Module

Chen, Wen-fei 14 January 2010 (has links)
In this study, the optical simulation software Light Tools was executed to reduce the LED amount used by improving the performance of light guide plate of backlight module with LED illuminator. The improvement of the design including: 1.replacing the V-cut microstructures on the lower layer of the light guide plate by the micro-semispherical lens structures;2.replacing the diffusion film by the micro-semispherical lens structures on the upper layer of the light guide plate ; 3.adding the lateral microstructure on the light guide plate to reduce the dark-area phenomenon. The sizes of upper/lower microstructures, their spacings and the amount of LED were selected as the parameters and applying L18 orthogonal array to process the simulations firstly. Then integrating different kind of lateral microstructures to find the best uniformity, and obtain a set of parameters that could improve the performance of backlight module and then the amount of LED can be reduced. The results show that the uniformity of backlight module is over 88% without diffusion film which have overcome the requirement of 85% in traditional design with 2 diffusion films. This improvement not only reduces the cost from diffusion film, also removes the dark-area phenomenon. Additionally, the amount of LED is reduced to 45 from 48 that retrench about 7% of power. Energy and cost are saved simultaneously.
10

Fourier series-based optimization of LED angular intensity profiles for displays and backlighting

Beauchamp, Andrea January 2019 (has links)
A method using a Fourier series is demonstrated to optimize an LED array for local dimming applications in liquid crystal display backlighting. The same optimization method is also suitable for LED displays in which the Moiré effect must be suppressed during photography with a minimum loss of spatial resolution. Initially, the angular intensity profile of a Lambertian LED is modelled when backlighting a Lambertian rear projection screen and compared to experimental data. An array of optimized LEDs and the resulting screen intensity pattern is then derived such that an intensity distribution with an intensity deviation of less than 2% is achieved. The angular intensity profile of the LED is modified using adjustable Fourier coefficients optimized according to an algorithm. The algorithm is designed to achieve an illuminated screen area of maximum size for a bounded LED backlight array to appear uniform in intensity to an observer. This Fourier series approach provides an elegant method to optimize the intensity profile of LED backlight arrays without the use of ray tracing. A lens was designed in order to provide this optimized intensity profile as well as created and tested. / Thesis / Master of Science (MSc)

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