A back-plank structure of direct-type backlight module with equal parasitic capacitors

The display contrast and efficiency of power consumption for LCDs (Liquid Crystal Displays) continue to attract attention from both industry and academia. Local dimming approaches for direct-type backlight modules (BLMs, also referred to as backlight units, BLUs) are regarded as a potential solution. The purpose of this study is to explore how to optimize the local dimming method of LCD to achieve higher contrast and lower power consumption through deep learning techniques. In this paper, we propose a local dimming approach with dual modulation for LCD-LED displays based on VGG19 and UNet models. Experimental results have shown that this method not only reconstructs the input image into an HDR (High Dynamic Range) image but also automatically generates a control image for the backlight module and LCD panel. In addition, the proposed method can effectively improve the contrast and reduce the power consumption of the LCD in the absence of a public training dataset. Our method can achieve the best performance in MSE and HDR-VDP-2 among eight different combinations of mask and pre-training. Using deep learning techniques, this study has successfully optimized the local dimming approach of LCDs and demonstrated its benefits in improving contrast and reducing power consumption.

Photopolymers have been applied in many Additive Manufacturing (AM) systems and mostly are cured by UV light. Biodegradable photo-curable polymers are very limited and are not commercially available. DLP-projected maskless AM systems become more and more popular nowadays, but its working area is limited if the part resolution is required. For larger working envelope purpose, liquid crystal display (LCD) panel has great potentials, and LCD’s resolution has been improved significantly in the past few years due to the smart phone application. Therefore, in this research, LCD panel is used to replace DLP for a maskless AM system to cure biodegradable materials, Polycarprolactone (PCL) and Poly(ethylene glycol) diacrylate (PEG-DA). Due to the characteristics of LCD panel, the material systems should be sensitive and photo-polymerized in visible-light range, particularly in RGB. In this study, various percentages of visiblelight photoinitiator, Irgacure 784, in the material systems were investigated. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were utilized to characterize cured biomaterials. Because of the use of photoinitiator, the biocompatibility of the cured materials was also concerned, and hence, MTT assay tests were performed. The preliminary tests of fabrication, using the LCD-projected maskless AM system, cured grid patterns to illustrate the feasibility. The visible-light-curable PCL and PEG-DA will be able to be adopted in tissue engineering scaffold applications in the future.

We developed an electroholography unit, which consists of a special-purpose computational chip for holography and a reflective liquid-crystal display (LCD) panel, for a three-dimensional (3D) display. The special-purpose chip can compute a computer-generated hologram of 800x600 grids in size from a 3D object consisting of approximately 400 points in approximately 0.15 seconds. The pixel pitch and resolution of the LCD panel are 12 mum and 800x600 grids, respectively. We implemented the special purpose chip and LCD panel on a printed circuit board of approximately 28cmx13cm in size. After the calculation, the computer-generated hologram produced by the special-purpose chip is displayed on the LCD panel. When we illuminate a reference light to the LCD panel, we can observe a 3D animation of approximately 3cmx3cmx3cm in size. In the present paper, we report the electroholographic display unit together with a simple 3D display system.

Two new impulsive driving technologies for 120Hz liquid crystal display (LCD) panels are proposed to improve moving picture quality. One technology generates the dark frame using an adder and a shifter simply without using any look up tables (LUTs). It results in a cost effective impulsive scheme with motion picture quality comparable to that of high speed driving. The other is a backlight flashing method designed to avoid ghost images. The issue of ghost images caused by the slow response time of liquid crystal (LC) is solved by means of 120Hz overdriving and 120Hz backlight flashing. Using the perceived blur edge time (PBET) metric, measured moving picture response time (MPRT) values were 10.8ms and 4.4ms, respectively, while that of 120Hz high speed driving was 10.1ms.

Using image analysis techniques to enhance TFT-LCD manufacturing yield through timely detection of PI alignment layer defects

In‐cell sensor technology applied in Liquid Crystal Displays (LCDs) panels are investigated to enable adaptive adjustment of screen brightness and color temperature based on ambient light, thereby enhancing the display performance of screens in various environments. By incorporating ambient light sensors (ALS) and color temperature sensors (CTS), which are compatible with the normal manufacturing process of LCD panels, TCL CSOT has achieved a technological upgrade compared to traditional LCDs technology. In‐cell ALS referred to a wide sensing range of 0~10000 lux and high resolution of 1 lux below 50 lux. In‐cell CTS showed an effective range of 3500~9000 K with detection accuracy of 800 K. With these sensors, LCDs panel can adaptively change its brightness and color temperature within different environments, leading to a new feature of TV, monitor and other commercial LCDs.

The occurrence of leakage current (also called ground current) that can occur in photovoltaic (PV) system depends strongly on the value of parasitic capacitance between PV cell and its metal frame, usually earth connected. This paper presents a straightforward approach to calculate the involved panel parasitic capacitance in order to predict the likeliness of such leakage current. A novel 2-D parasitic edge capacitance model is developed to accurately calculate the grounding capacitance of PV panel. Experimental results are obtained on five different PV panels of mono-crystalline, polycrystalline and thin-film type with rated power 10W, 50W and 175W. It is demonstrated that the proposed approach combines easy of applications and satisfying accurateness.

A back light module is a key product for providing sufficient light source for a liquid crystal display (LCD). The light guide plate (LGP), used to increase the light usage rate, is a key component in the back light module. This study researches the microinjection molding process parameters and the quality performance of the LGP. Its purpose was to develop a combining Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) with the Taguchi method. This is to optimize the multiquality performance of the LGP for the injection molding manufacturing process, in which both the LCD and the LGP spontaneously produce the best quality performance for V‐cut depth and angle. First, an L18 orthogonal array was planned for the manufacturing parameters that affect the microinjection molding process. These included cooling time, mold temperature, melt temperature, injection speed, injection pressure, packing pressure, packing switching, and packing time. The TOPSIS was used to deal with the single‐quality optimization disadvantage of the Taguchi method. Then, the TOPSIS response table was used to obtain the optimized manufacturing parameters combination for a multiresponse process optimization. From the analysis of variance, the significant factors for the quality performance of the LGP could be obtained. In other words, by controlling these factors, it was possible to efficiently control the quality performance of the LGP. Finally, with the five verified experiments, the optimized processing parameters came within a 95% confidence interval. © 2010 Wiley Periodicals, Inc. Adv Polym Techn 29:54–63, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20181

The fine-tube cold cathode fluorescent lamp (CCFL) [1-2] and external electrode fluorescent lamp (EEFL) [3-9], have been widely used as a backlight source in liquid crystal display (LCD) modules. In a notebook PC, the glass tube diameter of the lamp is a small as 1 mm. As the display area becomes larger in LCD TVs, the tube diameter is 3~4 mm and the lamp length is up to 1~2 m. However, the mechanism for radiation of light along such a long positive column is not well understood. The characteristics of light emission in the EEFLs have been reported, specifically the propagation of a light-emitting along a tube driven by high voltage AC [8-9]. In the long positive column lamp, the light emits first from the side of high voltage propagates to the ground side with the propagation time of ~┤s and the propagation velocity of 105~106 m/s. The previous observations have not been reported elsewhere to our knowledge since the fluorescent lamps have been introduced commercially in the 1940's. However, those observations of light propagation would not be recognized even if they have been found first in the history of fluorescent lamps. Even more, those observations are misapprehended as the kinds of unstable waves during the lamp operation of lamp, such as striation, snaking, flickering, and streaming, etc. Generally, a moving light source in the long positive column plasma has been associated with “striation”. A striation is a quasistanding wave which can be observed visually [1012]. However, striations as well as the other unstable waves are not observed in commercial lamps, and would be considered a major defect for hot cathode fluorescent tubes as well as CCFL. In the manufacture of those lamps, inadequate vacuum during the evacuation process results in impurity gases such as H2O, CO2, O2, and N2, etc. These impurities cause the perturbations of unstable discharge, and those lamps are discarded in the production line. Striations can sometimes appear in aging lamps or in the operation with an unstable inverter system. However, we have never observed striations in the normally manufactured lamps of our test samples. Our observation of optical signal is quite different from striations, as it is not visible to the naked eye and moves on the micro-second timescale. Rather than the instability, they are related to the stable process of distribution of plasma and fields that generate light in these discharges.

This article documents the results of the first in a series of experiments designed to evaluate the suitability of a novel, high resolution, color, digital, liquid crystal display (LCD) panel for diagnostic quality, gray scale image display. The goal of this experiment was to measure the performance of the display, especially with respect to luminance. The panel evaluated was the IBM T221 22.2" backlit active matrix liquid crystal display (AMLCD) with native resolution of 3840 x 2400 pixels. Taking advantage of the color capabilities of the workstation, we were able to create a 256-entry grayscale calibration look-up table derived from a palette of 1786 nearly gray luminance values. We also constructed a 256-entry grayscale calibration look-up table derived from a palette of 256 true gray values for which the red, green, and blue values were equal. These calibrations will now be used in our evaluation of human contrast-detail perception on this LCD panel.

We present a method to display an integral three-dimensional (3D) image without gaps between multiple display active areas by using multiple liquid crystal display (LCD) panels and multi-image combining optical systems (MICOS). We designed a MICOS to improve the resolution characteristics and decrease the luminance unevenness corresponding to the viewpoint. Furthermore, we developed a method for correcting the distortion of the integral 3D image by using image processing. We prototyped an integral 3D display using four 8K dual-green (8KDG) LCD panels and the improved MICOSs. The prototype display achieved to magnify the display area about 5.66 times more than when a single LCD panel was used.

A digital time‐modulation pixel memory circuit on glass substrate has been designed and verified in a 3‐μm low temperature poly‐silicon (LTPS) technology. The proposed circuit can generate 4‐bit digital codes and the corresponding inversion data by time‐modulation technique to refresh the static image without activating the data driver circuit. Therefore, the data driver of liquid crystal display (LCD) panel is not required to provide the image data of the frame by the proposed circuit while the LCD panel operates in the still mode. The power consumption from data driver can be further reduced in the LCD panel.

A photolithography processing and wet-etching technology for use in forming ZnO transparent electrodes that are just a few micrometers in line-widths for application to Liquid Crystal Display (LCD) panels was developed. The chemicals (developed or obtained commercially) used for the photolithography process included a strong alkaline photoresist-developer, an alkaline photoresist-stripper with pH11-13 and a weak acidic etchant with pH 5.5-6.8 suitable for ZnO compound films with amphoteric properties. Optimization of the process conditions for photolithography and etching played a critical part in the development of the technology. We succeeded in forming transparent fine-patterns of Ga-doped ZnO films with 4 micronmeter line-widths and space-widths using this method. These fine line sizes indicate that our technology has reached a technical level comparable to those used for forming the ITO fine-pattern electrodes currently used for commercially available LCD panels.

Our previous study demonstrated massive emissions of liquid crystal monomers (LCMs) from liquid crystal display (LCD)-associated e-waste dismantling; however, the compositions, priority list, and inventory of LCMs in waste LCD panels remain unknown. Herein, we conducted the first comprehensive identification covering a broader range of LCMs, including 21 biphenyls and analogues (BAs), 28 cyanobiphenyls and analogues (CBAs), and 44 fluorinated biphenyls and analogues (FBAs), in waste television/computer LCD panels. A total of 64 of the 93 target LCMs, including 19 BAs, 6 CBAs, and 39 FBAs, were widely detected in collected waste LCD panels. Approximately 10-18 of the 64 detectable LCMs were identified as the main compositions in various waste LCD panels, which contributed to >90% of the total LCMs. Total concentrations of FBAs in the television/computer LCD panel samples were comparable to those of BAs but much higher than those of CBAs, indicating FBAs and BAs being the commonly used LCM categories. The composition distribution of LCMs varied between television/computer LCDs and among different brands of television/computer LCDs. A preliminary estimate of the globally direct release of LCMs from waste television/computer LCD panels into various environmental compartments was about 1.07-107 kg/year, which will increase considerably in the near future.

Anisotropic conductive films (ACFs) are adhesive films with anisotropic conductivity induced by dispersing conducting particles such as metal coated plastic balls and metal particles into polymer matrices such as thermoplastics and thermosetting resins. ACFs have been widely used for driver IC packaging technologies in FPDs(Flat panel displays) such as LCDs(Liquid crystal displays) for last two decades. So far various packaging technologies such as TCP(Tape carrier package) on LCD panel or PWB(Printed wiring board), COF(Chip on flex) on LCD panel or PWB, and COG(Chip on Glass) using ACFs have been realized to meet the requirement of fine pitch capability and make the flat panel displays smaller, lighter and thinner. In this paper, the history of ACF and driver IC packaging are described. In addition, it is mentioned that how important driver IC packaging is in implementing the miniaturization, high resolution, low cost and high display quality. ACF material design for COF which is advantageous in fine pitch interconnection is described. It is indicated that low temperature curable ACF is very useful in improving productivity of LCD modules and reducing the thermal stress at the interface in large LCD modules. We also indicates that the warpage of LCD panel after COG interconnection induces the light linkage issue in LCD modules. Lowering bonding temperature of ACF is also very important in reducing the warpae issue and avoiding the light linkage issue when COG is applied for driver IC packaging in large LCD modules.