LED资料译文
LED种类及英文翻译

LED种类及英文翻译LED是一种发光二极管(Light Emitting Diode)的简称,它是一种能够将电能转换为光能的固态发光装置。
由于其能耗低、寿命长、颜色鲜艳、体积小等优点,LED在照明、显示、通信等领域得到了广泛应用。
下面将介绍一些常见的LED种类及其英文翻译。
1. 蓝色LED(Blue LED)蓝色LED是一种利用镓化合物与氮化镓材料制成的发光二极管,其发射蓝光的波长通常在450纳米左右。
2. 绿色LED(Green LED)绿色LED是基于磷化镓材料制成的发光二极管,其发射绿光的波长通常在520纳米左右。
3. 红色LED(Red LED)红色LED是利用化合物半导体材料制成的发光二极管,其发射红光的波长通常在620-630纳米之间。
4. 黄色LED(Yellow LED)黄色LED是通过掺杂化合物半导体材料制成的发光二极管,其发射黄光的波长通常在580纳米左右。
5. 橙色LED(Orange LED)橙色LED是一种发射橙光的发光二极管,其波长介于红光和黄光之间。
6. 紫色LED(Purple LED)紫色LED是通过掺杂化合物半导体材料制成的发光二极管,其发射紫光的波长通常在380-420纳米之间。
7. 白色LED(White LED)白色LED是一种通过使用荧光材料或混合红、绿、蓝三种发光二极管的光源,以实现白光发射。
8. 红外线LED(Infrared LED)红外线LED是一种发射红外线光的发光二极管,其波长通常大于700纳米。
9. 紫外线LED(Ultraviolet LED)紫外线LED是一种发射紫外线光的发光二极管,其波长通常小于400纳米。
10.RGBLEDRGBLED是一种由红、绿、蓝三种颜色的发光二极管组合而成的,通过控制各个LED的开关,可以通过光的混合达到所需的颜色。
11. 定向LED(Directional LED)定向LED是一种能够将光束集中在特定方向的LED,例如高亮度发光二极管(High-brightness LED)和高功率发光二极管(High-power LED)。
LED道路照明中文翻译版本资料

– 白光LED将会拥有更高的色温, 会比其他光源更白
• 不会像钠灯那样黄 • 不会是卤素灯丝那样的琥珀色 • 灵便性
– 由于其离散特性,LEDs 有很广的品种范围,可以为设计者在灯的外观上 提供很大的灵活性
LED Roadway Lighting: Background, Challenges, and Solutions, Slide 20
Illuminance
LED Roadway Lighting: Background, Challenges, and Solutions, Slide 16
色温(CCT)
• 一个“黑体”的操作温度同与之比对的光源/发射器的 颜色外观相同
– 例如: 一个CRT的CCT是9300 K 这个CRT的外观(白色)和操作
• Cree 科锐 – XR-E – XR-C – MC-E – XP-E – XP-C – 4550 – XR
• Nichia 日亚 – Dozens of LEDs
• Cotco 华刚 • 更多…
LED Roadway Lighting: Background, Challenges, and Solutions, Slide 21
LED 道路照明: 背景, 挑战, 与解决方案
2009年2月 美国光学协会 莎益博设计系统商贸(上海)有限公司翻译
Copyright © 2008 Optical Research Associates
提纲
• 道路照明
– 分类 – 设计标准
• 照明基础 • 发光二极管
• 设计方法 -非序列光学问题
光度定义(2)
• 照度 (lux)
E Incident A
LED灯说明书中英文介绍

第8页光源系列 LAMP Series闪射系列 FLASHING SERIES外形设计美观、烟尘式散热排气孔Beautiful and decent appearance design, Smoke-Dust cooling exhaust hole产品特性 PRODUCTS FEATURES灯体采用6063航空铝材,冷锻式一体成型,外形新颖,美观大方;独有烟尘式散热设计,通过散热排气孔能更快的带走热量,散热效率高;电源采用美国BCD方案设计,高精度智能控制电路,具有过载欠压等保护,使用更安全;进口一体化透镜,透光率高达93%,表面鳞面设计,更好的防止眩光;新型EMC超导热大功率灯珠,具有高光效,高显指,采用陶瓷支架,散热效果更好,将低光衰。
The lamp body is made of 6063 aviation aluminum with novel and beautiful appearance. Product Category: Cold Forging, Integrated molding.Cooling Design: Unique Smoke-Dust Type, it can take away heat faster through the vent holes, so the cooling efficiency is very high.Power source: Using BCD solution design from US with precision smart control circuit, overload & under voltage protection, keeps it more secure.Lens: Integrated lens imported from abroad, light transmission rate is as high as 93%, and the surface design uses Scaly surface, so it can prevent glare much better;New EMC Lamp beads: superconducting heat and high power, high luminance, and high color render index.Ceramic bracket: provides better heat dissipation and low light decay.应用范围商业重点照明、酒店重点照明、装饰照明、专卖店、咖啡厅、KTV、超市、写字楼、书房、面包店、书店、家居等场所。
关于LED的外文文献和中文译文

多个LED发光装置的新型采集系统作为光源的一种,发光二极管(LED)有很多优点。
LED集成度更高,颜色种类多,使用寿命更长,而且工作电压较低。
但是,它仍有一个非常大的缺陷:一只LED的光照强度还是比较低。
这个缺点导致显示屏上的光通量不会很高。
但是无论如何,LED还是以其出色的性能在低电压装置中普遍应用。
因此,利用此系统采集多个LED的光,集成为更高强度的照明装置。
本设计提出三种采集系统,来实现增强光强的功能。
效率最好的一种采集系统可以达到96%。
同时,还分析了本系统的制造误差以及预算。
1 简介利用传统的光源来设计一个便携式探照灯,尺寸和能耗会很大。
而利用LED 来设计将会避免这些问题。
LED有很多优点:节能、体积较小、使用寿命长(约100,103小时)等,尤其是LED的光很适合环境工作。
Carel Zeiss和Philips打算用LED光源设计两种便携式探照灯。
尽管LED有诸多优点,可以让他们设计出的探照灯更加便携和小巧,但是由于光学元件的转换效率问题,导致系统有很多困难。
解决这个困难将是本文研究的重点。
通常,用一种合成非线性集中器(CPC)来减小分散度。
但是,这种传统的CPC采集效率仅为72%,必须要改善采集效率来提高光的利用率。
本文中将解决分散度和采集效率两个问题。
为实现这个目标,设计了三种不同的采集系统,以提高效率,下面逐一介绍。
2 仿真部分利用光学仿真软件和标签查找模块(BRO),来设计并分析采集系统的性能。
LED光源部分来自Osram-Opical半导体。
远程LED光源是一种Lambertian模式,LED的规格见表1。
在采集系统的底部有四个LED。
系统各个LED之间的位置关系如图1。
通光部分为2.1×2.1mm2,孔径3.26mm。
LED阵列对称的分布于系统的底部。
采集系统的第一个光学元件为均质器。
这个均质器的受光角度是12.5°。
因此,这个系统就是要把LED的受光角度的范围控制在±60°到±12.5°之间。
LED英文资料及中文翻译

First LED SummaryLED (Light Emitting Diode), light-emitting diode, is a solid state semiconductor devices, which can be directly converted into electricity to light. LED is the heart of a semiconductor chip, the chip is attached to one end of a stent, is the negative side, the other end of the power of the cathode, the entire chip package to be epoxy resin. Semiconductor chip is composed of two parts, part of the P-type semiconductor, it inside the hole-dominated, the other side is the N-type semiconductor, here is mainly electronic. But linking the two semiconductors, among them the formation of a "PN junction." When the current through the wires role in this chip, will be pushing e-P, P zone in the hole with electronic composite, and then to be issued in the form of photon energy, and this is the principle of LED luminescence. The wavelength of light that is the color of light, is formed by the PN junction of the decisions of the material.Second LED history and development50 years ago, people have to understand semiconductor materials can produce light of the basic knowledge, the first commercial diodes in 1960. English is the LED light emitting diode (LED) acronym, and its basic structure is an electroluminescent semiconductor materials, placed in a wire rack, then sealed with epoxy resin around, that is, solid package, Therefore, the protection of the internal batteries can play the role of line, so the seismic performance LED good.LED is the core of the P-type semiconductor and components of the N-type semiconductor chips, the P-type semiconductor and N-type semiconductor between a transition layer, called the PN junction. In some semiconductor materials in the PN junction, the injection of a small number of carrier-carrier and the majority of the extra time will be in the form of light energy to release, thus the power to direct conversion of solar energy. PN junction on reverse voltage, a few hard-carrier injection, it is not luminous. This use of injection electroluminescent diodes is produced by the principle of light-emitting diodes, commonly known as LED. When it in a positive state of the work (that is, at both ends with forward voltage), the current flows from the LED anode, cathode, semiconductor crystals on the issue from the ultraviolet to infrared light of different colors, light and the strength of the currents.Instruments used for the first LED light source instructions, but all kinds of light colored LED lights in traffic and large screen has been widely applied, have a very good economic and social benefits. The 12-inch red traffic lights as an example, is used in the United States have long life, low-efficiency 140 watt incandescent lamp as a light source, it produced 2,000 lumens of white light. The red filter, the loss-90 percent, only 200 lumens of red light. In the light of the new design, Lumileds companies have 18 red LED light source, including the loss of circuit, atotal power consumption of 14 watts to generate the same optical effect. Automotive LED lights is also the source of important areas.For general lighting, people need more white light sources. The 1998 white LED successful development. This is the GaN LED chip and Yttrium Aluminum Garnet (YAG) package together cause. GaN chip of the Blu-ray (λ p = 465nm, Wd = 30nm), made of high-temperature sintering of the Ce3 + YAG phosphors excited by this Blu-ray after irradiating a yellow, the peak 550 nm. Blue-chip installed in the LED-based Wanxing reflection in the cavity, covered with a resin mixed with YAG thin layer, about 200-500 nm. LED-based tablets issued by the Blu-ray absorption part of the phosphor, the phosphor another part of the Blu-ray and a yellow light mixed, can be a white. Now, the InGaN / YAG white LED, YAG phosphor by changing the chemical composition of the phosphor layer and adjust the thickness of the3500-10000 K color temperature can be colored white. This blue LED through the method by white, constructed simple, low-cost, high technology is mature, so use the most.The development of LED display can be divided into the following phases: first phase 1990 to 1995, mainly monochrome and 16 color graphics screen. Used to display text and simple images, mainly used in railway stations, financial securities, banks, post offices and other public places, as public information display tools. The second stage is from 1995 to 1999, there have been 64, 256 level gray-scale two-color video screen. Video control technology, image processing, optical fiber communication technology applications will enhance the LED display to a new level. LED display control LSI chips special at this time developed by domestic companies, and can be applied. The third stage, from 1999, red, pure green, blue LED in bulk into China, while domestic enterprises in-depth research and development work, using red, green, and blue LED production of full-color display has been widely used , poured into sports stadiums, convention centers, squares and other public places, which will bring the domestic large-screen full-color era. With the rapid development of LED materials market, surface mount device is available from 2001, mainly used in indoor full color, and its high brightness, colorful, low temperature characteristics, the point spacing can be adjusted by different price Requirements were accepted, in just two years time, product sales have more than 300 million yuan, surface mount full-color LED display application market entered the new century. To meet the 2008 Olympic Games, "downsizing" plan, Liard developed a surface mount dual color displays, a lot of time for the training center and game scoring. Full color in Olympic venues, in order to tighten investment, full color way is mostly detachable, live during the Olympic Games as a tool can be used for rental after the event, as the performance of national policies such as public places, tools released by In this way cost recovery as soon as possible. On the market, China's accession to WTO, Beijing's successful Olympic bid and so on, into the development of LED display industry, a new opportunity. Domestic LED display market continues to grow, currently in the domestic market, domestic LED display market share of nearly 95%. LED display theinternational market capacity is expected to 30% a year growth rate. Currently, LED display manufacturers concentrated primarily in Japan, North America, China LED manufacturers in which the insignificant share of exports. According to incomplete statistics, the world, there are at least 150 manufacturers full color, in which products are complete, the larger company has some 30 or so.Third LED advantagesConductor light-emitting diode (LED) as a third-generation semiconductor lighting source. This fantastic product has a lot of advantages: (1) efficient light: spectra of almost all concentrated in the visible light frequency, the efficiency can reach 80% -90%. The luminous efficiency of incandescent visible light efficiency of almost 10% -20% only. (2) high quality of light: not as a result of spectrum UV and infrared, there is no heat, no radiation, is typically a green light illumination. (3) energy consumption of the small: single power generally 0.05-1w, through the cluster can be tailored to meet different needs, and waste very little. As a light source, under the brightness in the same power consumption of only ordinary incandescent 1/8-10.(4) long life: flux attenuation to 70% of the standard life expectancy is 100,000 hours.A semiconductor light can be used under normal circumstances 50 years, even if the long life of the people, life will be used up to two lights. (5) durable and reliable: No tungsten wire, glass and other easily damaged components, non-normal retirement rate is very small, very low maintenance costs. (6) the application of flexibility: small size, can flat pack, easy to develop into a short thin products, make point, line, face various forms of specific applications. (7) Security: working voltage 1.5-5v or less in between the current 20-70mA in between. (8) green: recyclable waste, no pollution, unlike fluorescent lamps containing mercury as ingredients. (9) response time is short: to adapt to frequent and high-frequency switching operation of occasions.Fourth Classification of LED display1, color by color can be divided intoSingle-color display: Single color (red or green).Two-color display: red and green dual-color, 256 gray scale levels, can display 65,536 colors.Full-color screen: red, green, blue color, 256 grayscale full color display can display more than 16 million kinds of colors.2, according to display device classificationLED Digital Display: 7 segment display devices for the digital control code, suitable for production of the clock screen, the interest rate screens, showing the number of electronic display.LED dot-matrix graphic display: display device is arranged by a number of uniform composition of the dot-matrix LED display modules, suitable for broadcast text, image information.LED video display: display devices are formed by a number of light-emitting diodes that can display video, animation and other video files.3, by using the occasion categoriesIndoor Display: LED spots smaller, general Φ3mm - Φ8mm, shows the general area of a few to more than ten square meters.Outdoor Display: dozens of square meters in size to several hundred square meters, high brightness, can work in the sun, with wind, rain, water resistant.4, classified according to light spot diameterIndoor screen: Φ3mm, Φ3.75mm, Φ5mm,Room external screen: Φ10mm, Φ12mm, Φ16mm, Φ19mm, Φ20mm, Φ21mm, Φ22mm, Φ26mmRoom external screen as the basic unit of light emitting tube, LED tube principle is a set of red, green, and blue light-emitting diode sealed in a plastic barrel and jointly develop5, Display a static, horizontal scroll, vertical scroll and flip display. One block module control drive 12 (up to control 24) 8X8 Dot Matrix, a total of 16X48 dot matrix (or 32X48 dot matrix), is a single block of MAX7219 (or PS7219, HD7279, ZLG7289 and 8279, and the like LED display driver module) 12 times (or 24 times)! Can use "cascade" approach the composition of any large dot matrix display. Effects, good power consumption, and the MAX7219 circuit than the use of lower cost.Fifth LED applicationsIt is a semiconductor light-emitting diode by controlling the display, which probably look like that from lots of small red lights are usually formed by the bright lights off to show character. Used to display text, graphics, images, animations, quotes, video, video signals and other information on the display screen.Graphic display and LED display into the video display by the LED matrix blocks. Graphic displays can be synchronized with the computer display Chinese characters, English text and graphics; video display using micro-computer control, graphics, images, and Mao, real-time, synchronization, clear message to the broadcast of a variety of information dissemination, but also shows two dimensional, three-dimensional animation, video, TV, VCD programs and live on. LED display shows the screen brightly colored, three-dimensional sense of strong, static, such as painting, moving as the film is widely used in finance, tax, business, telecommunications, sports, advertising, industrial enterprises, transport, education systems, stations, docks, airports, shopping malls, hospitals, hotels, banks, securities markets, construction market, auction houses, industrial enterprises in management and other public places.LED display can show changes in the numbers, text, graphics and video; not only can be used in the indoor environment can also be used for outdoor environment, with a projector, TV wall, LCD screen can not match advantage.Sixth LED screen test methodA look at Screen size, appearance, smoothness, with the screen connection and so onSecond look after the dead pixel screen light up, not in not within the scope of (in general the screen is basically gone now)Color consistency, display text is normal, display pictures, play full screen full color to white, red, green, and blue.一 LED概述LED(Light Emitting Diode),发光二极管,是一种固态的半导体器件,它可以直接把电转化为光。
LED报告相关中英文对照

衬底技术:LED 衬底材料;衬底结构;衬底抛光;衬底切割;衬底掺杂;衬底(substrate underlayment substratum)材料(material)结构(structure formation)抛光(polishing)切割(cut)掺杂(doping)外延技术:外延工艺,外延退火;LED 缓冲层,LED 覆盖层,LED 量子阱,LED 晶格,LED 接触层外延(epitaxial)工艺(manufacturing process)退火(annealing)缓冲层(buffer layer)覆盖层(covering layers ; overlay)量子阱(quantum well)晶格(lattice)超晶格(superlattice)接触层(contact layer)芯片技术:芯片结构;芯片制造;表面粗糙;外形;光子晶体;衬底剥离;衬底健合;导光结构;划片;刻蚀;钝化;电极;芯片(chip)结构(structure formation)制造(manufacturing,manufacture)表面(surface)粗糙(rough)外形(form;appearance)光子(photon,photonic)晶体(crystal)剥离(stripping)健合(bond)导光(Light conducting;Guiding light)划片(dicing)刻蚀(etching)钝化(Passivation)电极(electrode)封装技术:封装体、基座、透镜、反射体、引线、引线框架、热沉、白光、荧光粉、测量、导光板、粘结剂、材料、改进、形状、结构;封装(encapsulation;packaging)透镜(lens)反射体(reflector)引线框架(Leadframe)引线(Lead wire)热沉(Heat sink)白光(white light)荧光粉(phosphor)测量(measure)导光板(light guide plate;Light conducting plate)粘结剂(adhesive)材料(material)改进(Modified)结构(structure formation)形状(shape,form)应用技术:汽车照明、室内照明、手机背光源、液晶显示背光源应用(application)汽车(car,automobile,vehicle)室内(Indoors,room)手机(Mobile,cellphone)照明(illumination,lighting)液晶显示(LCD,liquid crystal display)背光源(Backlight source)荧光材料:荧光芯片;荧光封装体;荧光基板;荧光材料芯片;荧光反射体;荧光粘结剂;荧光导光板;荧光间隔膜;荧光有源层;荧光材料(Fluorescent material)芯片(chip)荧光粉(phosphor)封装体(package)基板(substrate)材料(material)反射体(reflector)粘结剂(adhesive)导光板(light guide plate;Light conducting plate)间隔膜(diaphragm)有源层(active layer)。
LED英文资料及中文翻译

First LED SummaryLED (Light Emitting Diode), light-emitting diode, is a solid state semiconductor devices, which can be directly converted into electricity to light. LED is the heart of a semiconductor chip, the chip is attached to one end of a stent, is the negative side, the other end of the power of the cathode, the entire chip package to be epoxy resin. Semiconductor chip is composed of two parts, part of the P-type semiconductor, it inside the hole-dominated, the other side is the N-type semiconductor, here is mainly electronic. But linking the two semiconductors, among them the formation of a "PN junction." When the current through the wires role in this chip, will be pushing e-P, P zone in the hole with electronic composite, and then to be issued in the form of photon energy, and this is the principle of LED luminescence. The wavelength of light that is the color of light, is formed by the PN junction of the decisions of the material.Second LED history and development50 years ago, people have to understand semiconductor materials can produce light of the basic knowledge, the first commercial diodes in 1960. English is the LED light emitting diode (LED) acronym, and its basic structure is an electroluminescent semiconductor materials, placed in a wire rack, then sealed with epoxy resin around, that is, solid package, Therefore, the protection of the internal batteries can play the role of line, so the seismic performance LED good.LED is the core of the P-type semiconductor and components of the N-type semiconductor chips, the P-type semiconductor and N-type semiconductor between a transition layer, called the PN junction. In some semiconductor materials in the PN junction, the injection of a small number of carrier-carrier and the majority of the extra time will be in the form of light energy to release, thus the power to direct conversion of solar energy. PN junction on reverse voltage, a few hard-carrier injection, it is not luminous. This use of injection electroluminescent diodes is produced by the principle of light-emitting diodes, commonly known as LED. When it in a positive state of the work (that is, at both ends with forward voltage), the current flows from the LED anode, cathode, semiconductor crystals on the issue from the ultraviolet to infrared light of different colors, light and the strength of the currents.Instruments used for the first LED light source instructions, but all kinds of light colored LED lights in traffic and large screen has been widely applied, have a very good economic and social benefits. The 12-inch red traffic lights as an example, is used in the United States have long life, low-efficiency 140 watt incandescent lamp as a light source, it produced 2,000 lumens of white light. The red filter, the loss-90 percent, only 200 lumens of red light. In the light of the new design, Lumileds companies have 18 red LED light source, including the loss of circuit, atotal power consumption of 14 watts to generate the same optical effect. Automotive LED lights is also the source of important areas.For general lighting, people need more white light sources. The 1998 white LED successful development. This is the GaN LED chip and Yttrium Aluminum Garnet (YAG) package together cause. GaN chip of the Blu-ray (λ p = 465nm, Wd = 30nm), made of high-temperature sintering of the Ce3 + YAG phosphors excited by this Blu-ray after irradiating a yellow, the peak 550 nm. Blue-chip installed in the LED-based Wanxing reflection in the cavity, covered with a resin mixed with YAG thin layer, about 200-500 nm. LED-based tablets issued by the Blu-ray absorption part of the phosphor, the phosphor another part of the Blu-ray and a yellow light mixed, can be a white. Now, the InGaN / YAG white LED, YAG phosphor by changing the chemical composition of the phosphor layer and adjust the thickness of the3500-10000 K color temperature can be colored white. This blue LED through the method by white, constructed simple, low-cost, high technology is mature, so use the most.The development of LED display can be divided into the following phases: first phase 1990 to 1995, mainly monochrome and 16 color graphics screen. Used to display text and simple images, mainly used in railway stations, financial securities, banks, post offices and other public places, as public information display tools. The second stage is from 1995 to 1999, there have been 64, 256 level gray-scale two-color video screen. Video control technology, image processing, optical fiber communication technology applications will enhance the LED display to a new level. LED display control LSI chips special at this time developed by domestic companies, and can be applied. The third stage, from 1999, red, pure green, blue LED in bulk into China, while domestic enterprises in-depth research and development work, using red, green, and blue LED production of full-color display has been widely used , poured into sports stadiums, convention centers, squares and other public places, which will bring the domestic large-screen full-color era. With the rapid development of LED materials market, surface mount device is available from 2001, mainly used in indoor full color, and its high brightness, colorful, low temperature characteristics, the point spacing can be adjusted by different price Requirements were accepted, in just two years time, product sales have more than 300 million yuan, surface mount full-color LED display application market entered the new century. To meet the 2008 Olympic Games, "downsizing" plan, Liard developed a surface mount dual color displays, a lot of time for the training center and game scoring. Full color in Olympic venues, in order to tighten investment, full color way is mostly detachable, live during the Olympic Games as a tool can be used for rental after the event, as the performance of national policies such as public places, tools released by In this way cost recovery as soon as possible. On the market, China's accession to WTO, Beijing's successful Olympic bid and so on, into the development of LED display industry, a new opportunity. Domestic LED display market continues to grow, currently in the domestic market, domestic LED display market share of nearly 95%. LED display theinternational market capacity is expected to 30% a year growth rate. Currently, LED display manufacturers concentrated primarily in Japan, North America, China LED manufacturers in which the insignificant share of exports. According to incomplete statistics, the world, there are at least 150 manufacturers full color, in which products are complete, the larger company has some 30 or so.Third LED advantagesConductor light-emitting diode (LED) as a third-generation semiconductor lighting source. This fantastic product has a lot of advantages: (1) efficient light: spectra of almost all concentrated in the visible light frequency, the efficiency can reach 80% -90%. The luminous efficiency of incandescent visible light efficiency of almost 10% -20% only. (2) high quality of light: not as a result of spectrum UV and infrared, there is no heat, no radiation, is typically a green light illumination. (3) energy consumption of the small: single power generally 0.05-1w, through the cluster can be tailored to meet different needs, and waste very little. As a light source, under the brightness in the same power consumption of only ordinary incandescent 1/8-10.(4) long life: flux attenuation to 70% of the standard life expectancy is 100,000 hours.A semiconductor light can be used under normal circumstances 50 years, even if the long life of the people, life will be used up to two lights. (5) durable and reliable: No tungsten wire, glass and other easily damaged components, non-normal retirement rate is very small, very low maintenance costs. (6) the application of flexibility: small size, can flat pack, easy to develop into a short thin products, make point, line, face various forms of specific applications. (7) Security: working voltage 1.5-5v or less in between the current 20-70mA in between. (8) green: recyclable waste, no pollution, unlike fluorescent lamps containing mercury as ingredients. (9) response time is short: to adapt to frequent and high-frequency switching operation of occasions.Fourth Classification of LED display1, color by color can be divided intoSingle-color display: Single color (red or green).Two-color display: red and green dual-color, 256 gray scale levels, can display 65,536 colors.Full-color screen: red, green, blue color, 256 grayscale full color display can display more than 16 million kinds of colors.2, according to display device classificationLED Digital Display: 7 segment display devices for the digital control code, suitable for production of the clock screen, the interest rate screens, showing the number of electronic display.LED dot-matrix graphic display: display device is arranged by a number of uniform composition of the dot-matrix LED display modules, suitable for broadcast text, image information.LED video display: display devices are formed by a number of light-emitting diodes that can display video, animation and other video files.3, by using the occasion categoriesIndoor Display: LED spots smaller, general Φ3mm - Φ8mm, shows the general area of a few to more than ten square meters.Outdoor Display: dozens of square meters in size to several hundred square meters, high brightness, can work in the sun, with wind, rain, water resistant.4, classified according to light spot diameterIndoor screen: Φ3mm, Φ3.75mm, Φ5mm,Room external screen: Φ10mm, Φ12mm, Φ16mm, Φ19mm, Φ20mm, Φ21mm, Φ22mm, Φ26mmRoom external screen as the basic unit of light emitting tube, LED tube principle is a set of red, green, and blue light-emitting diode sealed in a plastic barrel and jointly develop5, Display a static, horizontal scroll, vertical scroll and flip display. One block module control drive 12 (up to control 24) 8X8 Dot Matrix, a total of 16X48 dot matrix (or 32X48 dot matrix), is a single block of MAX7219 (or PS7219, HD7279, ZLG7289 and 8279, and the like LED display driver module) 12 times (or 24 times)! Can use "cascade" approach the composition of any large dot matrix display. Effects, good power consumption, and the MAX7219 circuit than the use of lower cost.Fifth LED applicationsIt is a semiconductor light-emitting diode by controlling the display, which probably look like that from lots of small red lights are usually formed by the bright lights off to show character. Used to display text, graphics, images, animations, quotes, video, video signals and other information on the display screen.Graphic display and LED display into the video display by the LED matrix blocks. Graphic displays can be synchronized with the computer display Chinese characters, English text and graphics; video display using micro-computer control, graphics, images, and Mao, real-time, synchronization, clear message to the broadcast of a variety of information dissemination, but also shows two dimensional, three-dimensional animation, video, TV, VCD programs and live on. LED display shows the screen brightly colored, three-dimensional sense of strong, static, such as painting, moving as the film is widely used in finance, tax, business, telecommunications, sports, advertising, industrial enterprises, transport, education systems, stations, docks, airports, shopping malls, hospitals, hotels, banks, securities markets, construction market, auction houses, industrial enterprises in management and other public places.LED display can show changes in the numbers, text, graphics and video; not only can be used in the indoor environment can also be used for outdoor environment, with a projector, TV wall, LCD screen can not match advantage.Sixth LED screen test methodA look at Screen size, appearance, smoothness, with the screen connection and so onSecond look after the dead pixel screen light up, not in not within the scope of (in general the screen is basically gone now)Color consistency, display text is normal, display pictures, play full screen full color to white, red, green, and blue.一 LED概述LED(Light Emitting Diode),发光二极管,是一种固态的半导体器件,它可以直接把电转化为光。
led照明毕业论文中英文资料外文翻译文献

led照明毕业论文中英文资料外文翻译文献Renewable and Sustainable Energy ReviewsHigh-brightness LEDs—Energy efficient lighting sources and their potential in indoor plant cultivation ABSTRACTThe rapid development of optoelectronic technology since mid-1980 has significantly enhanced the brightness and efficiency of light-emitting diodes (LEDs). LEDs have long been proposed as a primary light source for space-based plant research chamber or bioregenerative life support systems. The raising cost of energy also makes the use of LEDs in commercial crop culture imminent. With their energy efficiency, LEDs have opened new perspectives for optimizing the energy conversion and the nutrient supply both on and off Earth. The potentials of LED as an effective light source for indoor agriculturalproduction have been explored to a great extent. There are many researches that use LEDs to support plant growth in controlled environments such as plant tissue culture room and growth chamber. This paper provides a brief development history of LEDs and a broad base review on LED applications in indoor plant cultivation since 1990.Contents1. Introduction2. LED development.3. Color ratios and photosynthesis4. LEDs and indoor plant cultivation.4.1. Plant tissue culture and growth4.2. Space agriculture84.3. Algaculture4.4. Plant disease reduction5. Intermittent and photoperiod lighting and energy saving6. Conclusion1. IntroductionWith impacts of climate change, issues such as more frequent and seriousdroughts, floods, and storms as well as pest and diseases are becoming more serious threats to agriculture. These threats along with shortage of food supply make people turn to indoor and urban farming (such as vertical farming) for help. With proper lighting, indoor agriculture eliminates weather-related crop failures due to droughts and floods to provide year-round crop production, which assist in supplying food in cities with surging populations and in areas of severe environmental conditions.The use of light-emitting diodes marks great advancements over existing indoor agricultural lighting. LEDs allow the control of spectral composition and the adjustment of light intensity to simulate the changes of sunlight intensity during the day. They have the ability to produce high light levels with low radiant heat output and maintain useful light output for years. LEDs do not contain electrodes and thus do not burn out like incandescent or fluorescent bulbs that must be periodically replaced. Not to mention that incandescent and fluorescent lamps consume a lot of electrical power while generating heat, which must be dispelled from closed environments such as spaceships and space stations.2. LED developmentLED is a unique type of semiconductor diode. It consists of a chip of semiconductor material doped with impurities to create a p–n junction. Current flows easily from the p-side (anode), to the n-side (cathode), but not in the reverse direction.Electrons and holes flow into the junction from electrodes with different voltages. When an electron meets a hole, it falls into a lower energy level, and releases energy in the form of a photon. The color (wavelength) of the light emitted depends on the band gap energy of the materials forming the p–n junction. The materials used for an LED have a direct band gap with energies corresponding to near-infrared, visible or near-ultraviolet light.The key structure of an LED consists of the die (or light-emitting semiconductor material), a lead frame where the die is placed, and the encapsulation which protects the die (Fig. 1).Fig.1LED development began with infrared and red devices made with gallium arsenide. Advances in materials science have made possible the production of devices with ever-shorter wavelengths, producing light in a variety of colors. J.Margolin reported that the first known light-emitting solid state diode was made in 1907 by H. J. Round. No practical use of Round’s diode was made for several decades until the invention of the first practical LED by Nick Holonyak, Jr in 1962. His LEDs became commercially available inlate 1960s. These GaAsP LEDs combine three primary elements: gallium, arsenic and phosphorus to provide a 655nm red light with brightness levels of approximately 1–10 mcd at 20mA. As the luminous intensity was low, these LEDs were only used in a few applications, primarily as indicators. Following GaAsP, GaP (gallium phosphide) red LEDs were developed. These device sex hibit very high quantum efficiencies at low currents. As LED technology progressed through the 1970s, additional colors and wavelengths became available. The most common materials were GaP green and red, GaAsP orange, and high efficiency red and GaAsP yellow. The trend towards more practical applications (such as in calculators, digital watches, and test equipment) also began to develop. As the LED materials technology became more advanced, the light output was increased, and LEDs became bright enough to be used for illumination.In 1980s a new material, GaAlAs (gallium aluminum arsenide) was developed followed by a rapid growth in the use of LEDs. GaAlAs technology provides superiorperformance over previously available LEDs. The voltage requirement is lower, which results in a total power savings. LEDs could be easily pulsed or multiplexed and thus are suitable for variable message and outdoor signs. Along this development period, LEDs were also designed into bar code scanners, fiber optic data transmission systems, and medicalequipment. During this time, the improvements in crystal growth and optics design allow yellow, green and orange LEDs only a minor improvement in brightness and efficiency. The basic structure of the material remained relatively unchanged.As laser diodes with output in the visible spectrum started to commercialize in late 1980s, LED designers used similar techniques to produce high-brightness and high reliability LEDs. This led to the development of InGaAlP (indium gallium aluminum phosphide) visible light LEDs. Via adjusting the energy band gap InGaAlP material can have different color output. Thus, green, yellow, orange and red LEDs could all be produced using the same basic technology. Also, light output degradation of InGaAlP material is significantly improved.Shuji Nakamura at Nichia Chemical Industries of Japan introduced blue LEDs in 1993. Blue LEDs have always been difficult to manufacture because of their high photon energies (>2.5 eV) and relatively low eye sensitivity. Also, the technology to fabricate these LEDs is very different and less advanced than standard LED materials. But blue is one of the primary colors (the other two being red and green). Properly combining the red, green, and blue light is essential to produce white and full-color. This process requires sophisticated software and hardware design to implement. In addition, the brightness level is low and the overall light output of each RGB die being used degrades at a different rate resulting in an eventual color unbalance. The blue LEDs available today consist of GaN (gallium nitride) and SiC (silicon carbide) construction. The blue LED that becomes available in production quantities has result in an entire generation of new applications that include telecommunications products, automotive applications, traffic control devices, and full-color message boards. Even LED TVs can soon become commercially available.Compare to incandescent light’s 1000-h and fluorescent light’s 8000-h life span, LEDs have a very significantly longer life of 100,000 h. In addition to their long life, LEDs have many advantages over conventional light source. These advantages include small size, specific wavelength, low thermal output, adjustable light intensity and quality, as well as high photoelectric conversion efficiency. Such advantages make LEDs perfect for supporting plant growth in controlled environment such as plant tissue culture room and growth chamber. Table 1 is a list of some common types of LEDs as compiled from .The chlorophyll molecules in plants initiate photosynthesis bycapturing light energy and converting it into chemical energy to help transforming water and carbon dioxide into the primary nutrient for living beings. The generalized equation for the photosynthetic process is given as:CO2 + H2O—light—>(CH2O)+ O2where (CH2O) is the chemical energy building block for thesynthesis of plant components.Chlorophyll molecules absorb blue and red wavelengths most efficiently. The green and yellow wavelengths are reflected or transmitted and thus are not as important in the photosyntheticprocess. That means limit the amount of color given to the plants and still have them grow as well as with white light. So, there is no need to devote energy to green light when energy costs are aconcern, which is usually the case in space travel.The LEDs enable researchers to eliminate other wavelengths found within normal white light, thus reducing the amount of energy required to power the plant growth lamps. The plants grow normally and taste the same as those raised in white light.Red and blue light best drive photosynthetic metabolism. These light qualities are particularly efficient in improving the developmental characteristics associated with autotrophic growth habits. Nevertheless, photosynthetically inefficient light qualities also convey important environmental information to a developing plant. For example, far-red light reverses the effect of phytochromes, leading to changes in gene expression, plant architecture, and reproductive responses. In addition, photoperiod (the adjustment of light and dark periods) and light quality (the adjustment of red, blue and far-red light ratio) also have decisive impacts on photomorphogenesis.The superimposed pattern of luminescence spectrum of blue LED (450–470 nm) and that of red LED (650–665 nm) corresponds well to light absorption spectrum of carotenoids and chlorophyll. Various plant cultivation experiments are possible when these twokinds of LED are used with the addition of far-red radiation (730–735 nm) as the light source. Along the line of the LED technology advancement, LEDs become a prominent light source for intensive plant culture systems and photobiological researches. The cultivation experiments which use such light sources are becoming increasingly active. Plant physiology and plant cultivation researches using LEDs started to peak in 1990s and become inevitable in the new millennium. Those researches have confirmed that LEDs are suitable for cultivation of a variety of algae,crop, flower, fruit, and vegetable.Some of the pioneering researches are reviewed in the followings.Bula et al. have shown that growing lettuce with red LEDs in combination with blue tubular fluorescent lamp (TFL) is possible. Hoenecke et al. have verified the necessity of blue photons for lettuce seedlings production by using red LEDs with blue TFL. As the price of both blue and red LEDs have dropped and the brightness increased significantly, the research findings have been able to be applied in commercial production. As reported by Agence France Press, Cosmo Plant Co., in Fukuroi, Japan has developed a red LED-based growth process that uses only 60% of electricity than a fluorescent lighting based one.Tennessen et al. have compared photosynthesis from leaves of kudzu (Pueraria lobata) enclosed in a leaf chamber illuminated by LEDs versus by a xenon arc lamp. The responses of photosynthesis to CO2 are similar under the LED and xenon arc lamps at equal photosynthetic irradiance. There is no statistical significant difference between the white light and red light measurements in high CO2. Some leaves exhibited feedback inhibition of photosynthesis which is equally evident under irradiation of either lamp type. The results suggest that photosynthesis research including electron transport, carbon metabolismand trace gas emission studies should benefit greatly from the increased reliability, repeatability and portability of a photosynthesis lamp based on LEDs.Okamoto et al. have investigated the effects of different ratios of red and blue (red/blue) photosynthetic photon flux density (PPFD) levels on the growth and morphogenesis of lettuce seedlings. They have found that the lettuce stem length decreases significantly with an increase in the blue PPFD. The research has also identified the respective PPFD ratio that (1) accelerates lettuce seedlings’stem elongation, (2) maximizes the whole plant dry weight, (3) accelerates the growth of whole plants, and (4) maximizes the dry weights of roots and stems. Photosynthesis does not need to take place in continuous light. The solid state nature allows LEDs to produce sufficient photon fluxes and can be turned fully on and off rapidly (200 ns), which is not easily achievable with other light sources. This rapid on–off feature has made LEDs an excellent light source for photosynthesis research such as pulsed lighting for the study of photosynthetic electron transport details. The off/dark period means additional energy saving on top of the LEDs’low power consumption.4. LEDs and indoor plant cultivation4.1. Plant tissue culture and growthTissue culture (TC), used widely in plant science and a number of commercial applications, is the growth of plant tissues or cells within a controlled environment, an ideal growth environment that is free from the contamination of microorganisms and other contaminants. A controlled environment for PTC usually means filtered air, steady temperature, stable light sources, and specially formulated growth media (such as broth or agar). Micropropagation, a form of plant tissue culture (PTC), is used widely in forestry and floriculture. It is also used for conserving rare or endangered plant species. Other uses of PTC include:1short-term testing of genetic constructions or regeneration oftrans genic plants,2 cross breeding distantly related species and regeneration of the novel hybrid,3 screening cells for advantageous characters (e.g. herbicidere sistance/tolerance),4embryo rescue (i.e. to cross-pollinate distantly related specie sand then tissue culture there sulting embryo which would normally die),5 large-scale growth of plant cells in liquid culture inside bioreactors as a source of secondary products (like recombinant proteins used as biopharmaceuticals).6production of doubled monoploid plants from haploid cultures to achieve homozygous lines more rapidly in breeding programs (usually by treatment with colchicine which causes doubling of the chromosome number).Tissue culture and growth room industries have long been using artificial light sources for production. These light sources include TFL, high pressure sodium lamp (HPS), metal halide lamp (MHL) and incandescent lamp, etc. Among them, TFL has been the most popular in tissue culture and growth room industries. However, the use of TFL consumes 65% of the total electricity in a tissue culture lab. That is the highest non-labor costs. As a result, these industries continuously seek for more efficient light sources. The development of high-brightness LED has made LED a promising light source for plant growth in controlled environments.Nhut et al. have cultured strawberry plantlets under different blue to red LED ratios as well as irradiation levels and compared its growth to that under plant growth fluorescent. The results suggest that a culture system using LED is advantageous for the micropropagation of strawberry plantlets. The study also demonstrates that the LED light source for in vitro culture of plantlets contributes to an improved growth of the plants in acclimatization.Brown et al. have measured the growth and dry matter partitioning of ‘Hungarian Wax’pepper (Capsicum annuum L.) plants grown under red LEDs compared with similar plants grown under red LEDs with supplemental blue or far-red radiation. Pepper biomass reduces when grown under red LEDs without blue wavelengths compared to plants grown under supplemental blue fluorescent lamps. The addition of far-red radiation results in taller plants with greater stem mass than red LEDs alone. Fewer leaves developed under red or red plus far-red radiation than with lamps producing blue wavelengths. The results of their research indicate that with proper combination of other wavelengths, red LEDs may be suitable for the culture of plants in tightly controlled environments.4.2. Space agricultureBecause re-supply is not an option, plants are the only options to generate enough food, water and oxygen to help make future explorers self-sufficient at space colonies on the moon, Mars or beyond. In order to use plants, there must be a light source. Standard light sources that used in homes and in greenhouses and in growth chambers for controlled agriculture here on Earth are not efficient enough for space travel. While a human expedition outside Earth orbit still might be years away, the space farming efforts are aimed at developing promising artificial light sources. LEDs, because of their safety, small mass and volume, wavelength specificity, and longevity, have long been proposed as a primary light source for space-base plant research chamber or bioregenerative life support systems .Infrared LEDs that are used in remote controls devices have other uses. Johnson et al. have irradiated oat (Avena sativa cv Seger) seedlings with infrared (IR) LED radiation passed through a visible-light-blocking filter. The irradiated seedlings exhibited differences in growth and gravitropic response when compared to seedlings grown in darkness at the same temperature. This suggests that the oat seedlings are able to detect IR LED radiation. These findings also expand the defined range of wavelengths involved in radiation–gravity (light–gravity) interactions to include wavelengths in the IR region of the spectrum.Goins et al. grow wheat under red LEDs and compare them to the wheat grown under (1) white fluorescent lamps and (2) red LEDs supplemented with blue light from blue fluorescent lamps. The results show that wheat grown under red LEDs alone displayed fewer subtillers and a lower seed yield compared to those grown under white light. Wheat grown under red LEDs + 10% BF light had comparable shoot dry matter accumulation and seed yield relative to those grown under white light. These results indicate that wheat can complete its life cycle under red LEDs alone, but larger plants and greater amounts of seed are produced in the presence of red LEDs supplemented with a quantity of blue light.The research of Goins and his team continues in plant growth chambers the size of walk-in refrigerators with blue and red LEDs to grow salad plants such as lettuce and radishes. They hope the plant growth chamber would enable space station staff to grow and harvest salad greens, herbs and vegetables during typical fourmonth tours on the outpost .4.3. AlgacultureAlgaculture, refers to the farming of species of algae, has been a great source for feedstock, bioplastics, pharmaceuticals, algae fuel, pollution control, as well as dyes and colorants. Algaculture also provides hopeful future food sources.Algae can be grown in a photobioreactor (PBR), a bioreactor which incorporates some type of light source. A PBR is a closed system, as opposed to an open tank or pond. All essential nutrients must be introduced into the system to allow algae to grow and be cultivated. A PBR extends the growing season and allows growing more species. The device also allows the chosen species to stay dominant. A PBR can either be operated in ‘‘batch mode’’or ‘‘continuous mode’’in which a continuous stream of sterilized water that contains air, nutrients, and carbon dioxide is introduced. As the algae grows, excess culture overflows and is harvested.When the algae grow and multiply, they become so dense that they block light from reaching deeper into the water. As a result, light only penetrates the top 7–10 cm of the water in most algalcultivation systems. Algae only need about 1/10 the amount of direct sunlight. So, direct sunlight is often too strong for algae. A means of supplying light to algae at the right concentration is to place the light source in the system directly.Matthijs et al. have used LEDs as the sole light source in continuous culture of the green alga (Chlorella pyrenoidosa). The research found the light output of the LED panel in continuous operation sufficient to support maximal growth. Flash operation at 5-ps pulse ‘‘on’’ duration between dark periods of up to 45 ps would stillsustain near maximum growth. While longer dark periods tend to cut the growth rate, the light flux decrease resulting from such operation does not reduce the growth as much as that of the similar flux decrease in continuous operation. Their research concludes that the use of flashing LEDs (which means intermittent light) in indoor algal culture yielded a major gain in energy economy comparing to fluorescent light sources. An additional advantage is that heat waste losses are much smaller. The most interesting discovery of this study may be that adding blue light to the red LED light did not change the growth properties.In order to take advantage of the biotechnological potential of algae, Lee and Palsson have calculated theoretical values of gas mass transfer requirements and light intensity requirements to support high-density algal cultures for the 680 nm monochromatic red light from LED as a light source. They have also designed a prototype PBR based on these calculations. Using on-line ultra filtration to periodically provide fresh medium, these researchers have achieved a cell concentration of more than 2×109cells/ml (more than 6.6%, vol/vol), cell doubling times as low as 12 h, and an oxygen production rate as high as 10 mmol oxygen/l culture/h. This research indicates that the development of a small LED-based algal photobioreactors is economically achievable.Another research of algae via LEDs is conducted by Nedbal et al. Their research is a study of light fluctuation effects on a variety of algae in dilute cultures using arrays of red LEDs to provide intermittent and equivalent continuous light in small-size (30 ml) bioreactors. The results endorse that the algae growth rates in certain calculated intermittent light can be higher than the growth rate in the equivalent continuous light. Yanagi and Okamoto has grown five spinach plants under the red LEDs and another five under 40W plant growth fluorescent lamps at the same light intensity of 125 mmol/m2/s. The dry matter production under the LEDs is slightly less than that under the fluorescent lamps. The plant leaf area under the red LEDs is also smaller than that under the fluorescent lamps. Nevertheless, they reach a conclusion that LEDs can qualify as an artificial light source for plant growth.4.4.Plant disease reductionSchuerger and Brown have used LED arrays with different spectral qualities to determine the effects of light on the development of tomato mosaic virus (ToMV) in peppers and powdery mildew on cucumbers. Their research concludes that spectral quality may alter plant disease development. Latter research regarding bacterial wilt on tomato has confirmed this conclusion and demonstrates that spectral quality may be useful as a component of an integrated pest management program for space-based ecological life support systems. Schuerger et al. have shown that the spectral quality effects on peppers’ anatomical changes in stem and leaf tissues are corr elated to the amount of blue light in primary light source.Miyashita et al. use red LEDs (peak wavelength: 660 nm) and white fluorescent lamps as light sources for potato plantlets growth in vitro. They found that shoot length and chlorophyll concentration of the plantlets increases with increasing 630–690 nm red photon flux (R-PF) while there are no significant differences in dry weight and leaf area of the plantlets with different R-PF levels. This means red lightaffects the morphology rather than the growth rate of potato plantlets in vitro. As a result, they suggest that red LEDs can be used for controlling plantlet morphology in micropropagation.5. Intermittent and photoperiod lighting and energy savingTime constants for photosynthetic processes can be divided into three ranges: primary photochemistry, electron shuttling, and carbon metabolism. These three photosynthetic processes can be uncoupled by providing pulses of light within the appropriate range for each process. At high frequencies, pulsing light treatments can be used to separate the light reactions (light harvesting and charge separation) from the dark reactions (electron shuttling) of photosynthetic electron transport. LEDs’ flexible pulsating ability can be coupled with such characteristics of photosynthesis and lead to additional energy saving.Tennessen et al. use LEDs to study the effects of light pulses (micro- to milli-second) of intact tomato leaves. They found that when the equivalent of 50 mmol photons mp -2s-1 is provided during 1.5 ms pulses of 5000 mmol photons mp -2s-1 followed by 148.5 ms dark periods, photosynthesis is the same as in continuous 50 mmol photons mp -2s-1 . Data support the theory that photons in pulses of 100 ps or shorter are absorbed and stored in the reaction centers to be used in electron transport during the dark period. Pigments of the xanthophyll cycle were not affected by pulsed light treatments. This research suggests that, instead of continuous light, using effectively calculated intermittent light (which means less energy consumption) might not affect the plant production.Jao and Fang have investigated the effects of intermittent light on growth of potato plantlets in vitro. They also use conventional TFLs for the experiment to explore the electrical savings realized by adjusting the frequency and duty ratio of LEDs. TFLs provide continuous fluctuating light at 60 Hz while LEDs provide nonfluctuating light and pulse light of the preset frequency and duty ratio. When the growth rate is the only concern, LEDs at 720 Hz (1.4 ms) and 50% duty ratio with 16-h light/8-h dark photoperiod stimulated plant growth the most. When energy consumption is the major concern, using LEDs at 180 Hz (5.5 ms) and 50% duty ratio with 16-h light/8-h dark photoperiod would not significantly sacrifice plant growth, especially when energy for heat removal is also taken into account.6. ConclusionsThe first sustained work with LEDs as a source of plant lighting occurred in the mid-1980s when a lighting system for plant growth was designed for space shuttles and space stations for it is realized that people cannot go to the Moon, Mars, or beyond without first mastering the art of indoor farming on Earth. As the performance of LED continues to improve, these lighting systems progress from red only LED arrays using the limited components available to high-density, multi-color LED chip-on-board technologies. Today, space age gardeners who have been testing high-efficiency light sources for future space colonists have identified energy efficient LEDs as the major light source not only to grow food but also to generate and purify oxygen and water—key sustainers of human life. The removal of carbon dioxide from a closed environment is another added benefit.LEDs are the first light source to provide the capability of true spectral composition control, allowing wavelengths to match to plant photoreceptors to optimize production as well as to influence plant morphology and composition. They are easily integrated into digital control systems, facilitating complex lighting programs like varying spectral composition over the course of a photoperiod or with plant development stage. LEDs do not contain mercury. They are safer to operate than current lamps since they do not have glass envelopes or high touch temperatures.While the process of photosynthesis does not require continuous light of full spectrum, LEDs can produce sufficient photon fluxes of specific wavelength on and off rapidly. Such mechanism of photosynthesis coupled with the solid state characteristics of LEDs constitute two ways of energy saving (cutting out unnecessary spectrum segment and turning off the light periodically) on top of the LEDs’ low power consumption. These are not easily achievable with other light sources.This paper provides a broad base review on LED applications in horticulture industry since 1990. These researches pave the way for the researches of similar types using different species and lead to comparable conclusion that LEDs are well qualified to replace its more energy demanding counterparts as controlled environment light source for agricultural research such as providing tissue culture lighting as well as supplemental and photoperiod lighting for greenhouses.With the energy it can save, LED’s becoming ec onomically feasible in large-scale indoor farming lighting applications is just around the corner.再生可持续能源评论高亮高效节能LED灯的来源及其在室内植物栽培中的潜力摘要自1980年中期以来,光电子技术的迅猛发展,显著调高了发光二极管(LED)的亮度和效率。
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带集成反光镜和散热结构的金属封装二极管的热学和光学
性能
Jin Hwan Kim, Jong Hwa Choi, and Moo Whan Shin
摘要——我们设计了一个集反光杯和散热区集成与一体的LED光源。
从热瞬态测量获得的数据显示,集成结构的金属可以导致热性能的提高,我们花了很多研究来弄清LED的出光与金属表面内部的关系。
LED芯片的辐射通量计算热阻被用来作为输入参数来预测光功率和射线追踪。
远场模式的模拟光输出功率为145.3兆瓦,这与积分球测量值达到了很好的相符性。
结果表明大部分的反射光(3 7.12 mW)到达远处接收处之前就损失了。
这证明了第一个反光杯的角度是我们研究的金属封装结构的关键。
当第一反射镜角度优化从80度变为55度个(第二反射镜角度取50度时),光功率相比145.3 -170.15 mW的初始值增加了,并且出光效率从75.63%提高到88.57%。
射线追踪和照度光栅图也指出金属封装结构的光学性能的改善主要源于反射角度的优化。
1.介绍
发光二极管(LED)的应用扩展到许多领域,包括背光单元显示,通用灯具、医疗设备等。
随着对出光强度和功率的需求的不断提升,许多关于LED封装的研究着力于高效的散热和提高出光上面。
这是因为高温交界处会导致长期使用时寿命减少,并且对短期内固态照明的效率有坏处。
各种热与不同的材料和结构设计已经被开发并被商业化。
很特别的一种就是III-Nitride材料的热电性质的热设计高功率led的主动冷却系统的应用。
通常,由于LED塑料包装由于有低热传导性(例如聚邻苯二甲酰胺或者环氧玻璃布层压板),热阻通常是很大的(通常小于1W/mk)。
特别不同的是用于L ED封装的陶瓷材料,因为他们有各种优势包括高导热塑料材料。
陶瓷封装持久热强度分析的数据显示它有更好的热特性。
然而,结果表明陶瓷封装的低弹性系数会导致更高的形变场的压力。
散热部分和反光部分不连续的封装会导致有效的热耗散障碍,这些问题在最近的塑料和陶瓷封装中很常见。
在许多情况下两个热膨胀系数的不匹配的封装材料(CTE)之间在受热或制造加工时会导致分层。
分层是导致LED性能和寿命下降的主要因素之一。
尽管有着相对较高的重量和高的价格,金属也还是因为他们优良的导热性能而被使用。
另外,高延展性也是金属作为可能的LED封装材料的一个优势,尤其是对大规模工业生产。
然而,还没有任何关于消除了反光杯和封装间不连续性的金属封装结构被提出来。
在本文中,我们提出了一种新的封装结构,它的分散器和反光杯是用同一种金属制成。
将金属封装与传统塑料封装的热学和光学性质进行比较和评估后,表明金属封装因其一体化结构而在热血性能上有显著优势。
,此外,在光学性能方面,金属封装与塑料封装却基本没有任何差异。
2.实验步骤
新开发的金属封装是由下面的步骤完成的。
铜粉和有机粘结剂混合,混合物粘贴挤进一个模子后烧定型为设计的结构。
抛光后,通过与2微米镍和4微米银电镀在一起完成制造。
3 D模型的剖视图包检查图1中所示。
3结果与讨论
图2显示了有限体积模型测出的塑料和金属封装的温度分布。
在强制冷却条件下,连接点处温度塑料模型是75.9摄氏度,金属模型是50.3摄氏度。
这明显
表明金属封装比塑料封装具有更好的热学特性。
图3显示了热瞬态测试的实验结果,第一幅图比较的冷却曲线强制冷却条件下金属盒塑料封装,连接处金属封装温度是57摄氏度,而塑料封装是86摄氏度,测量结果与仿真结果吻合的很好。
仿真中这个较低的温度源于仿真中对于完美接触的假设。
第二幅图表现了2种结构的不同功能。
测量得出金属和塑料的总热阻分别是49 K/W和27 K/W。
结构函数的峰间阻力表明每一层的部分贡献包的总热阻。
部分电阻系列的包层由比较结构功能与封装结构和命名(从接点到双丙酮丙烯酰胺),(从双丙酮丙烯酰胺到散热器),(从散热器到外壳),(从外壳到周围环境)下标“m”和“p”代表分别金属封装和塑料封装。
为了弄清反射角度对光学性能的影响,图6显示了金属封装的初始和优化后的结构的模拟射线追踪和照度光栅图。
第一反射杯附近的射线追踪结果显示总体方向的反射光线。
显然未经优化的结构的可视化的反射光从传播主要在横向方向,而优化结构大量的反射光指向垂直方向。
照度的光栅图(在图6(b)和(d)),显示了发射光的照度分析。
分析,平面接收器表面收集的远离LED芯片400毫米的位置一平方米表面。
在每个图,颜色分布地图左边显示了根据坐标平面的照度接收器,右边描绘的是相应的相对频率表。
未经优化的结构椭圆的颜色分布(图.6(b))符合第一反射杯的形状。
它表明,
发出的光线从LED芯片主要局限于第一反射杯的边界。
然而,优化结构能让第一反射器发出的射线克服障碍,达到第二反射器在所有的方向。
反射镜角度相对较高时,入射和反射角度发出的射线和杯子的表面之间预计会降低。
这意味着光更有可能被反射回入射光的方向,又反射到另一边。
因此,在射出封装材料之前光会在里面来回反射好几次。
另一方面,当反射角度更低,入射和反射角度相对较高,因此光可以在更短的传播距离内被集中。
4结论
我们设计制造了一种集散热器和反光杯于一体的LED封装结构。
并且评估了金属封装的热学与光学性能,并与传统塑料封装做了比较。
表明了金属封装由于其一体化结构而具有显著的优势。
然而却显示出它有大量的出射光线由于与封装表面的相互作用,在到达远处的接收点之前就被耗散了。
近场和远场模拟显示, 金属封装的光学性能明显受反射角度的影响,特别是第一反射镜角度。
结果表明, 通过优化反射角度从80℃到55℃,光功率从原来的145.3毫瓦增加到170.15毫瓦。
金属的射线追踪和照度光栅图也能够解释金属封装的光学性质。
结论表示第一反光杯角度是发展高效金属封装主要的设计因数之一。