Étendue‐density homogenization lamps with light concentration function

Abstract— In order to increase the screen brightness of Digital Micromirror Device? projectors (DMD? projectors), we designed a new compact lamp. In our previous work, we discussed a lamp that has an aspherical lamp reflector and an aspherical front glass, which we called EHLa. Although EHLas improve the light convergence at the entrance of rod integrators, they require external lenses for light condensation. We, therefore, discuss a new EHLa that can converge light without the need for external lenses. The new lamp corresponds to conventional elliptic reflector‐type lamps, which are widely used for mobile‐type DMD? projectors. Our simulations demonstrated that the ratio of increased brightness is 17.1% for the new lamp design versus conventional lamps in a 0.7‐in.‐diagonal DDR DMD? panel.     

Development and application of less‐mercury flat fluorescent lamps for backlights and general lighting

Abstract— A novel flat discharge fluorescent lamp used as the light source of backlight modules for LCDs and general lighting systems has been researched and developed. This new type of lamp is a less‐mercury flat fluorescent lamp with two‐dimensional emission and superior to conventional one‐dimensional cold‐cathode fluorescent lamps in terms of optics, energy‐savings, production efficiency, reliability, and chromatic performances. Physical characterization of the optics, temperature, mechanical design, thermal shocking, reliability, and corresponding environments have verified that flat fluorescent lamps will be the next‐generation light sources for backlight modules and general lighting systems.     

A 100,000‐cd/m2 capacity‐coupled electrodeless discharge backlight with high efficacy for LC TVs

A capacity‐coupled electrodeless Hg discharge lamp has been developed for LC TV backlightings. By applying sinusoidal voltages which are 180° out of phase with a pair of external electrodes, a luminous uniformity of over 84% is attained in two types of lamps whose lengths are 190 and 390 mm. Luminance, efficacy, and input power to the lamp are 114,000 cd/m², 35 lm/W, and 21.5 W when the 390‐mm lamp is driven at 5 MHz. With a frequency below 1.1 MHz, eight 390‐mm lamps, connected in parallel to one another without external ballast impedance, can be driven by using a single inverter.     

Higher‐output more‐compact UHP lamp systems

Abstract— Projection systems have reached convincing performance with several thousand screen lumens created by systems of only a few liters in volume. With more than 10 lm/W they are the most efficient display systems realized today. The tremendous progress achieved up to now relies on the outstanding properties of the UHP lamp. The combination of high brightness with lifetimes extending up to more than 10,000 hours is ideal for projection applications. This paper will summarize some recent technological achievements: the volume of the lamp and driver system has been reduced by a factor of 10, exploiting a reduced ignition voltage as well as new optical concepts for the reflector. The optical performance of short‐arc projection lamps can be improved dramatically: a dichroic coating on one half of the UHP burner is applied to focus all light into one hemisphere. This allows for extremely compact reflector systems and an improvement by 20–30% in light collection.     

Color‐tuning projection system for adaptive combination of high brightness and wide color gamut

Abstract— The demand for projectors with high brightness and wide color gamut has been increasing; however, UHP lamp projectors cannot deliver those two qualities efficiently and simultaneously because of its color‐separation system. The newly developed projection system — “Color‐Tuning Projection System” — realizes the adaptive combination of high brightness and wide color gamut with one projector. This projector features a fourth liquid‐crystal panel — “Color Tuner” — with a 3LCD optical engine, which controls yellow light separately from the RGB light of a UHP lamp. This color‐tuner‐based optical engine — “Color‐Tuning Optical Engine” — and a new color‐conversion signal‐processing algorithm — “Adaptive Color Conversion Algorithm” — controls the yellow‐light volume and corrects color‐shifted pixels according to the brightness and chromaticity analysis of the input image, key technologies of the Color‐Tuning Projection System. This additional panel system enables the projector to ach ieve up to 115% higher brightness and 120% wider color gamut according to the input image. This paper presents an innovative design concept, a novel technology regarding brightness and a color‐gamut conversion projection system, and the characteristics of the prototype.     

Sphere‐supported thin‐film electroluminescence: A new platform technology for displays and lighting

Abstract— Currently, powder electroluminescence is used for low‐brightness flexible lamps offering durable plastic‐based lighting solutions principally for low‐ambient light conditions where lighting or backlighting is required. Sphere‐supported thin‐film electroluminescence (SSTFEL) promises dramatic new capability in both flexible lamps and displays owing to its high brightness and long‐life capability. SSTFEL is based on robust thin‐film phosphors deposited on spherical ceramic dielectric particles which are embedded in a thin plastic sheet. A printing approach permits versatile, low‐cost manufacturing of patterned SSTFEL devices and eliminates the need for high‐temperature substrates.     

室内照明智能控制技术研究与仿真

研究室内照明亮度调节优化问题,由于室内照明系统中,根据需要亮度各有不同。针对实际照度需求,为了能自动调整亮度,达到提高工作效率和节能的目的,提出建立遗传算法的室内灯具亮度调节精确模型。构建了以最小化照度误差和能量消耗的适应度函数,优化使亮度需求达到照度值。将灯具亮度调节分为场景切换和特定场景下灯具亮度微调两种模式,用不同场景灯具,对特定场景下需求亮度的调节进行了仿真,结果证明改进方法可以按不同照度需求时获得优化亮度。     

Mercury‐free 18‐in. flat fluorescent lamp with good uniformity

Abstract— We have developed an 18‐in. 287 × 359‐mm mercury‐free flat fluorescent lamp (FFL) having a new structure that utilizes dielectric barrier discharge and contains pure xenon gas. The electro‐optical characteristics have been analyzed. The surface luminance of the lamp having a diffuser sheet is 5600 cd/m² and the luminance uniformity is 92% at an applied voltage of 1050 Vrms and an applied frequency of 20 kHz in the form of a sine wave.     

High‐efficiency light‐collection optics for lamp‐based projection TV

Abstract— A new light‐collection optics has been developed that enhances the luminance of projection TV which use lamps as the light source. The conventional optical system consists of an elliptical reflector and a flat‐surface front glass, but these systems cannot sufficiently collect the beams coming from the light source, and they cause loss in the coupling with the light pipe. To solve this problem, we devised a new optical system through a structure of an aspherical reflector and an aspherical front glass. This new optical system concentrates the beams coming from the light source to a smaller point which improves the coupling efficiency. Thus, we have successfully increased the luminance of the projection TV by approximately 10%. This paper reports the design principles of the new optical system and the results of a prototype experiment.     

Mercury‐free 18‐in. flat fluorescent lamp with good uniformity

We have developed an 18‐in. 287 × 359‐mm flat fluorescent lamp (FFL) that uses a xenon dielectric barrier discharge and analyzed its electro‐optical characteristics. The surface luminance of the lamp having a diffuser sheet thickness of 3 mm was 5600 cd/m² and the luminance uniformity was 92% at an applied voltage of 950 Vrms. The luminous efficacy of the FFL was 24.5 lm/W for a luminance of 4200 cd/m² when driven by a sine‐wave voltage.     

Optimal maintenance planning for sustainable energy efficiency lighting retrofit projects by a control system approach

The energy savings achieved by implementing energy efficiency (EE) lighting retrofit projects are sometimes not sustainable and vanish rapidly given that lamp population decays as time goes by if without proper maintenance activities. Scope of maintenance activities refers to replacements of failed lamps due to nonrepairable lamp burnouts. Full replacements of all the failed lamps during each maintenance interval contribute to a tight project budget due to the expense for the lamp failure inspections, as well as the procurement and installation of new lamps. Since neither “no maintenance” nor “full maintenance” is preferable to the EE lighting project developers (PDs), we propose to design an optimal maintenance plan that optimises the number of replacements of the failed lamps, such that the EE lighting project achieves sustainable performance in terms of energy savings whereas the PDs obtain their maximum benefits in the sense of cost–benefit ratio. This optimal maintenance planning (OMP) problem is aptly formulated as an optimal control problem under control system framework, and solved by a model predictive control (MPC) approach. An optimal maintenance plan for an EE lighting retrofit project is designed as a case study to illustrate the effectiveness of the proposed control system approach.     

LCD backlights,light sources,and flat fluorescent lamps

Abstract— Backlights are indispensable for the operation of LCDs. Light sources or lamps are the core components of backlights. There are many types of light sources for backlights such as cold cathode fluorescent lamps (CCFLs), external electrode fluorescent lamps (EEFLs), hot‐cathode fluorescent lamps (HCFLs), flat fluorescent lamps (FFLs), and light‐emitting diodes (LEDs). Recently, FFLs are becoming one the most interesting light sources for LCD‐TV backlights. Channel profiles and the structure of FFLs in more detail are discussed in this paper. The channel profile of FFLs with maximum brightness uniformity was designed, fabricated, and characterized. The FFL backlight demonstrated 10,500 nits and the total power consumption was 110 W at room temperature.     

A directly addressed monolithic LED array as a projection source

Abstract— Light‐emitting‐diode arrays have been fabricated and demonstrated by several groups in a variety of applications in which structured illumination is desired, such as direct‐view displays and fluorescence detection. State‐of‐the‐art LEDs can achieve a high optical power density, exceeding 40 W/cm². This allows the use of such LEDs, if patterned into an array, as a light and pattern source for projection displays. As a proof of principle, a projection source using a monolithically integrated patterned LED array at a power density of 0.69 W/cm², a source brightness of 21,000,000 cd/m², and a projected brightness of 100,000 cd/m² is reported. It is shown that an improved version of such a display would allow significantly better power consumption and overall system efficiency than permitted by current projection‐display concepts.     

Airborne Vision-Based Navigation Method for UAV Accuracy Landing Using Infrared Lamps

In this paper, an airborne vision-based navigation method for Unmanned Aerial Vehicle (UAV) accuracy landing is presented. In this method, a visible light camera integrated with a Digital Signal Processing (DSP) processor is installed on the UAV and a 940 nm optical filter is fixed in front of the camera lens. In addition, four infrared light-emitting diode (LED) lamps whose emission wavelengths are 940 nm are placed behind ideal landing site on the runway. In this way, the infrared lamps in the image are distinct even if the image background is complicated. In the image processing procedure, firstly maximum between-class variance algorithm and region growing algorithm are used to determine candidate infrared lamp regions in the images. Then Negative Laplacian of Gaussian (NLOG) operator is applied to detect and track centers of the infrared lamps in the images. The space position and attitude of the camera can be obtained according to the corresponding relationship between image coordinates and space coordinates of the infrared lamp centers. Finally, high precision space position of the UAV can be calculated according to the installation relationship between the camera and the UAV. Plenty of real flight and static precision experiments have proved the validity and accuracy of the proposed method.     

Technology trends of high‐pressure mercury short‐arc lamps for projection systems

Abstract— We will discuss the advantages and limitations of ac and dc lamp technology for microdisplay‐based projection systems. The performance of the lamp in terms of brilliance and thermal robustness together with the potential lamp lifetime for ac and dc lamps will be discussed. ac and dc lamp designs will be evaluated to judge their potential for future improvements in terms of usable projector lumens.     

High‐luminance and luminous‐efficacy mercury‐free flat fluorescent lamp (MFFL) with local‐dimming functionality

Abstract— In order to realize high‐luminance and luminous‐efficacy mercury‐free flat fluorescent lamps (MFFLs) for LCD backlighting, the phosphor profile was optimized to enlarge the surface area. The proposed uneven profile of the rear phosphor increases the effective surface area of the phosphor, resulting in a wide luminance range from 3000 to 16,788 cd/m² with a corresponding high luminous efficacy from 66 to 34.7 lm/W, respectively. Also, a dynamic operation method for an adaptive local‐dimming and scanning operation is proposed which can be used in a 32‐in. multi‐structured configuration having one inverter system. With the deployment of the bipolar drive scheme and dual auxiliary electrodes, a stable and selective diffuse glow discharge with high luminance is possible.     

基于逐点路由的路灯组网方案设计

城市LED路灯推广效果明显,已在路面安装中占主要地位。但是LED路灯的测控系统暂未普及,特别是现场组网的成本和稳定性对测控系统的推广造成了制约。通过对比现有的现场组网技术,分析路灯安装环境和测控需求,设计出一套以网关为中心,以全部节点为路由进行逐点传递的现场通信网络方案,为实现现场网络的自组织能力,提出了相关的MAC协议,分析了网络组织过程,利用演绎改进的生成树设计出组网算法。基于逐点路由的组网方案具有廉价、简单、稳定的特点,有利于在现场组网工程中的应用推广。     

OLED‐based pico‐projection system

Abstract— Two pico‐projection systems, a monochrome green and a full‐color system, based on high‐efficiency OLED microdisplays (VGA; pixel size, 12 μm) are presented. Both optical systems are described by a numerical aperture of about 0.3, a magnification of 15x, and a working distance of 300–360 mm. The frequency limit of both systems is 42 cycles/mm at an image contrast of about 60%. The monochrome projection system with a volume smaller than 10 cm³ consists of one green OLED and a projection lens with five elements. The measured luminance in the image plane is about 0.061 lm. The image has a diagonal of 150 mm with a working distance of about 300 mm and has a considerable image contrast of 396:1. The second system combines three high‐brightness OLEDs, red, green, and blue colored, together with a projection lens and an image‐combining element, and an X‐Cube to achieve full‐color projection. The estimated luminance value for the three‐panel projection unit with an OLED luminance of 10,000 cd/m² for each display will be about Φcalculated = 0.147 lm. In this paper, the system concepts, the optical designs, and the realized prototypes of the monochrome and full‐color projection system are presented.     

Environmental and optical testing of Thin Crystal Film™ polarizers

Abstract— We have developed an advanced polarizing nanomaterial that provides new technical and economical advantages over traditional iodine film polarizers for LCD designers and manufacturers. Thin Crystal Film (TCF)? polarizer material is based on modified organic dichroic dyes and can be simply coated as a thin molecular oriented film (less than 1 μm) directly onto a plastic or glass substrate. This crystalline material exhibits enhanced viewing‐angle characteristics, high thermal stability, and lightfastness. Replacement of conventional polarizers by the new TCF polarizer allows decreasing thickness of LCD designs by 20–75%, improving LCD durability and reliability, all while significantly reducing cost. This paper presents TCF polarizer products for LCD applications. We report the results of TCF optical and environmental testing. Ultraviolet‐light photostability of TCF is also studied.     

Étendue‐density homogenization lens optimized for high‐pressure mercury lamps

Abstract— In order to increase the screen brightness of Digital Micromirror Device? projectors (DMD?), we have developed a new aspherical lens. Homogenizing the étendue‐density distribution made by a high‐pressure mercury lamp, this lens improves the light convergence at its focal point where the rod integrator's entrance is placed. Our simulation showed that the percentage of increase in brightness is up to 18.4%.