CN104715688A - Brand-new large-sized vehicle-mounted LED display multiple-screen linkage control device capable of improving color rendering property - Google Patents

Abstract

The invention provides a brand-new large-sized vehicle-mounted LED display multiple-screen linkage control device capable of improving a color rendering property. Light outlet parts of LEDs are doped with or not doped with a scattering agent, and are colored or colorless, LEDs of various colors can be divided into four types namely colored transparent, colorless transparent, colored scattering and colorless scattering LEDs; and scattering LEDs are suitable for being used as indicator lights.

Description

The large-scale vehicle LED that completely newly can improve colour rendering shows multi-screen ganged control device

The large-scale vehicle LED that the present invention completely newly can improve colour rendering shows multi-screen ganged control device and belongs to electronic applications.

Launch LED structure

LED(Light Emitting Diode), light emitting diode, formed primarily of support, elargol, wafer, gold thread, epoxy resin five kinds of materials.

LED is a kind of can be the semiconductor of luminous energy by electric energy conversion, and it changes the principle of the luminescence of incandescent lamp tungsten filament and the luminescence of electricity-saving lamp tricolor powder, and adopts electroluminescence.According to analysis, the feature of LED is very bright

LED bulb and light fixture section sheet (18) show, and the life-span is long, light efficiency is high, radiation is low and low in energy consumption.The spectrum of white light LEDs almost all concentrates on visible light frequency band, and its luminescence efficiency can more than 150lm/W(2010).LED and ordinary incandescent lamp, spiral energy-saving lamp and T5 three-color fluorescent lamp are contrasted, result shows: the light efficiency of ordinary incandescent lamp is 12lm/W, life-span is less than 2000 hours, the light efficiency of spiral energy-saving lamp is 60lm/W, life-span is less than 8000 hours, and T5 fluorescent light is then 96lm/W, and the life-span is approximately 10000 hours, and the white light LEDs light efficiency that diameter is 5 millimeters in theory can more than 150lm/W, the life-span can be greater than 100000 hours.Someone also predicts, following LED life-span upper limit is by infinity.Along with the improvement of LED heat dissipation technology, the high-power LED lighting fixtures such as exterior lighting LED, Projecting Lamp have realized suitability for industrialized production and have started to be widely applied.The stage lighting, studio's lamp etc. of the exigent room lighting of gentle colour rendering of checking colors also has realized volume production and has dropped into application.T8, T5, T4 fluorescent tube of the general illumination that the scope of application is maximum, consumption is also maximum and the screw socket bulb lamp of replacement incandescent lamp and electricity-saving lamp form seriation, and serviceable life is up to 50,000 hours.LED illumination enters high-speed development period.

Packing forms

According to the application occasion of difference, peculiar block dimension, heat radiation plan and luminous function.LED mode is varied.Current, LED primarily has the lamp-led packaging technology flow process sections such as Lamp-LED, TOP-LED, Side-LED, SMD-LED, High-Power-LED, Flip Chip-LED by packaged type classification

Lamp-LED(vertical LED)

That Lamp-LED presents in early days is straight cutting LED, and the mode of embedding is selected in its encapsulation.The process of embedding first in LED shaping mold cavity, injects liquid-state epoxy resin, then lunges the LED support that pressure welding is good, puts into baking oven and allow after epoxy resin cure, detached by LED namely shaping from die cavity.Because manufacture craft is relatively simple, cost is low, has higher market share.

SMD-LED(paster LED)

Paster LED is affixed on wiring board appearance, is applicable to SMT processing, can Reflow Soldering.The problems such as brightness, visual angle, flatness, reliability, consistance are processed well, lighter pcb board and reflector material are selected, the carbon steel material pin that straight cutting LED is heavier is eliminated after improvement, make the epoxy resin manifesting reflection horizon demand filling less, meaning section reduces yardstick, decline component.Like this, product component can be alleviated half by paster LED easily, finally makes utilization further satisfactory.

Side-LED(side-emitting LED)

Another of LED will count face, side light emitting package.If want to use LED when LCD(liquid crystal visualizer) back light, so face, the side luminescence of LED need be luminous the same with appearance, and LCD backlight luminescence just can be made even.No doubt use the description of lead frame, also can arrive the meaning section of face, side luminescence, but thermolysis is owed.But, Lumileds company creates the description of catoptron, by the LED of appearance luminescence, uses catoptron principle to send out into sidelight, is successfully used on large scale LCD backlight module by high-capacity LED.

TOP-LED(top light emitting LED)

Top light emitting LED is more common paster type light emitting type.Primarily apply to the backlight in Multifunctional ultrathin mobile phone and PDA and condition indicator.

High-Power-LED(high-capacity LED)

In order to obtain the LED light source of high power, high brightness, manufacturers carry out to high-power direction in LED chip and encapsulation description.Current, the LED that can accept number W power presents.The package layout of analogy Norlux series high-power LED is the multi-chip combination that base (make its non-conductive) made by sexangle aluminium sheet, base diameter 31.75mm, luminous zone is located heart position therebetween, diameter is (0.375 × 25.4) mm about, can contain 40 LED die, aluminium sheet is also as heat sink.Convention tube core high density assembled package is selected in this encapsulation, and luminous power is high, and thermal resistance is low, under big current, have higher optical output power, is also a kind of LED solid light source having Developing prospect.

Visible, the thermal characteristics of power-type LED directly has influence on the working temperature, luminous power, emission wavelength, service life etc. of LED, thus, describes the encapsulation of power type LED chip, makes technical ability and seem further important.

Flip Chip-LED(covers brilliant LED)

LED chip package layout is substantially shaped with a plurality of perforation at PCB, each perforation place of the side of this substrate is provided with two peculiar regions and the conductive material of opening a way each other, and this conductive material is laid in substrate in appearance, the LED chip of a plurality of un-encapsulated is had to be positioned over each perforation place of the side with conductive material, positive pole and the negative contacts of single LED chip be use tin ball respectively conductive material apparent with substrate be connected, and all put the sealing of transparent material towards the appearance of the side of perforation in a plurality of LED chip, this sealing is located each perforation place in a hemispheroidal shape.Be attributed to flip chip bonding layout light emitting diode.

LED can be directly luminous energy electric energy conversion.The heart of LED is the wafer of a semiconductor, one end attachment LED strain of wafer

On a support, be negative pole, the other end connects the positive pole of power supply, and whole wafer is got up by epoxy encapsulation.Semiconductor wafer is made up of two parts, and a part is P-type semiconductor, and inside it, occupy an leading position in hole, and the other end is N-type semiconductor, at this side mainly electronics.But time these two kinds of semiconductors couple together, between them, just form one " P-N junction ".When electric current acts on this wafer by wire time, electronics will be pushed to P district, and in P district, electronics is with hole-recombination, then will send energy with the form of photon, the principle of LED luminescence that Here it is.And the wavelength of light determines the color of light, determine by forming P-N junction material.Paster LED

Classification

1, divide by luminotron glow color

Can be divided into redness, orange, green (segment again yellowish green, standard is green and pure green), blue light etc.In addition, the chip of two kinds or three kinds colors is comprised in some light emitting diodes.

Mix or do not mix scattering diluent, coloured or colourless according to light emitting diode bright dipping place, the light emitting diode of above-mentioned shades of colour also can be divided into colored transparent, water white transparency, have chromatic dispersion and colourless scattering Four types.Scatter-type light emitting diode is suitable for lamp use of giving instruction.

2, divide by luminotron exiting surface feature

Cyclotomy lamp, square lamp, rectangle, face luminotron, lateral tube, surperficial installation miniature tube etc.Circular lamp is divided into φ 2mm, φ 4.4mm, φ 5mm, φ 8mm, φ 10mm and φ 20mm etc. by diameter.Usually the light emitting diode of φ 3mm is denoted as T-1 abroad; φ 5mm is denoted as T-1(3/4); φ 4.4mm is denoted as T-1(1/4).

Circular luminous intensity distribution situation can be estimated by half-value angle size.

Three classes are had from luminous intensity angle distribution Duan Laifen:

(1) high directivity.Be generally tip epoxy packages, or the encapsulation of band metal reflection cavity, and do not add scattering diluent.Half-value angle is 5 ° ~ 20 ° or less, has very high directive property, can be used as local lighting light source, or with optical detector coupling to form automatic checkout system.

(2) standard form.Usually be used as pilot lamp, its half-value angle is 20 ° ~ 45 °.

(3) scatter-type.This is the larger pilot lamp in visual angle, and half-value angle is 45 ° ~ 90 ° or larger, and the amount of scattering diluent is larger.

3, divide by the structure of light emitting diode

There is the structure such as the encapsulating of loopful oxygen, metab epoxy packages, ceramic base epoxy packages and glass-encapsulated.

4, divide by luminous intensity and working current

There is the LED(luminous intensity 10mcd of general brightness); Between 10 ~ 100mcd, high brightness LED is luminous intensity.The working current of general LED is at tens mA to tens mA, and the working current of low current LED is below 2mA (brightness is identical with common luminotron).

Except above-mentioned sorting technique, press chip material classification and the method by Function Classification in addition.　

Relevant knowledge

The brightness of pottery LED Ceiling light (9) LED has must be related to the lighting angle of LED, and its brightness less of the angle of LED is higher, and production technology is different, and serviceable life is slightly different.The luminous intensity of the white light at the LED180 degree angle of 5MM only has hundreds of MCD, light intensity 20,000 MCD more than 10,000 at 15 degree of angles, use high-power LED out of doors, brightness is just higher, single power has 1W, 3W, 5W, also have plenty of and become a high-power LED with multiple high power combination, power goes to hundreds of W to be had.

Colour temperature and brightness have no relations, and brightness is relevant with lumen value

Several related notion:

(1) luminous flux (lm)

Because the electromagnetic wave of human eye to different wave length has different sensitivity, we directly can not weigh luminous energy with the radiation power of light source or radiation flux, and must to adopt with the sensation amount of human eye to light be benchmark, and unit----luminous flux is weighed.Luminous flux symbol Φ represents, unit is lumen (lm).

(2) luminous intensity (cd)

Luminous flux is the total luminous energy illustrating that a certain light source is launched to surrounding volume.The luminous flux that Different Light sends is different in the distribution in space.The unit of luminous intensity is candela, and symbol is cd, and it represents the luminous flux that light source is launched in certain unit sphere degree solid angle (angle that this body surface is formed pointolite).1 cd=1 lm/1 sr (sr: the sterad unit of solid angle).

Pottery (5) (3) brightness (cd/m2)

Brightness be represent eyes from a direction see the intensity of object emission light.Unit is candela/square metre [cd/m2], and symbol is L, and show the luminous flux of luminophor in specific direction unit solid angle unit area, it equals the luminous intensity that 1 square metre sends 1 candela on the surface.

(4) colour temperature (Color Temperature)

When the color of color and the black matrix radiation at a certain temperature of the light that light source sends is identical, the temperature of black matrix is just called the colour temperature of this light source, with absolute temperature K(Kelvin, and degree Kelvin=degrees Celsius+273.15) represent.

Colour rendering (Color rendering property)

In principle, artificial light should be identical with available light, makes the naked eyes of people correctly can distinguish the color of things, and certainly, this will determine according to the position of illumination and object.

The degree that light source presents for object color is called colour rendering.Usually " colour rendering index " (Ra) is called.Color relationship shown under the true colors (color and luster of himself) that colour rendering refers to things and a certain standard sources.The determination of Ra value, be define in DIN6169 standard 8 kinds of test colors compared under standard sources and tested light source, aberration is less, shows that the colour rendering of measured light color is better.

Ra value be 100 light source represent, the color that things shows under its light is consistent with under standard sources.

Industry development is applied

In view of the intrinsic advantage of LED, be mainly used in following a few broad aspect:

(1) the application LED light fixture of display screen, traffic signal display light source has that antidetonation is shock-resistant, speed of photoresponse is fast, power saving and the feature such as the life-span is long, be widely used in various indoor, outdoor display screen, be divided into panchromatic, double-colored and single color display screen, the whole nation has 100 Duo Ge units in Development and Production.Traffic lights mainly use the red, green, yellow look LED of super brightness, because adopt LED signal lamp both energy-conservation, reliability is high again, so in China, traffic lights are just regenerated at progressive updating, and promotion rate is fast, market demand is very large, is a good market opportunity.

(2) the using vehicle lamp in auto industry comprises the instrument panel of automotive interior, acoustics indication lamp, the backlight of switch, the brake lamp of reading lamp and outside, taillight, side lamp and head lamp etc.The shock-sensitive dynamic shock of automobile incandescent lamp, fragile, the life-span is short, needs often to change.1987, China started on automobile, install LED high-mount stop lamp.Due to LED fast response time, can remind brake driver early, reduce rear-ended car accident, in developed country, the rearmounted high-mount stop lamp of central authorities using LED to manufacture has become the standard component of automobile, and Hewlett-Packard Corporation of the U.S. was at semiconductor lighting in 1996

The LED automobile tail lamp module released can arbitrarily be combined into various automobile tail light.In addition, at the light source of fascia and other various illumination section, all can take on by LED, so all progressively adopting LED to throw light on.Domestic Automotive Industry is in great development period, is the fabulous opportunity of promoting LED illuminating lamp.The output value of annual output 1000000000 yuan can be formed in recent years, the output value of annual 3000000000 yuan in 5 years, can be formed.

(3) LED backlight is the most noticeable with the backlight of efficient side luminescence, LED applies as LCD backlight, have that the life-span is long, luminescence efficiency is high, noiseless and cost performance high, be widely used in accutron, mobile phone, beeper, electronic calculator and machine for punching the card, along with portable electronic products small, LED backlight has more advantage, and therefore backlight manufacturing technology will to more slim, low-power consumption and the development of uniformity aspect.LED is mobile phone Primary Component, and a regular handset or Personal Handyphone System about need use 10 LED component, and a color screen and the mobile phone with camera function then need to use about 20 LED component.Present stage, cell phone back light source consumption was very large, and 1 year with 3,500,000,000 LED chips.China's mobile phone turnout is very large, and most of LED backlight or import, for domestic LED product, this is a fabulous market opportunity.

(4) the product luminescence efficiency that LED illumination light source is early stage is low, and light intensity generally can only reach several to dozens of mcd, is useful in indoor scenarios, applies in household electrical appliances, instrument and meter, communication apparatus, microcomputer and toy etc.Along with the improvement of LED heat dissipation technology, the alternative trend that LED light source substitutes incandescent lamp and fluorescent light or even the high power light source such as iodine-tungsten lamp, high-pressure mercury lamp develops from topical application field.Japan is economize energy, planning the light emitting diode project (being called " illuminating Japan ") of alternative incandescent lamp, the budget of 5 years is 5,000,000,000 yen, if LED substitutes incandescent lamp and the fluorescent light of half, the energy being equivalent to 6,000,000,000 liters of crude oil can be saved every year, be equivalent to the generated energy of five 1.35 × 106kW nuclear power stations, and the generation of carbon dioxide and other greenhouse gases can be reduced, improve people and to live the environment of living.China also greatly develops the semiconductor lighting plan of energy-conserving and environment-protective in investment 5,000,000,000 in 2004.

(5) other application examples is as a kind of Glittering shoes being subject to children and welcoming, and when walking, built-in LED can flashing, only 500,000,000 light emitting diodes in Wenzhou Area 1 year; Utilize light emitting diode as the battery capacity indication lamp of electric toothbrush, according to domestic manufacturer's introduction of going into operation, should

LED lamp (5) company has a small amount of tooth brush for health protection listing, needs 300,000,000 electroluminescent lamps every year when estimating batch production; Just at popular LED Christmas lamp, due to the security that modern design, rich color, non-friable broken and low pressure use, closely powerful in south east asia situations of sale such as Hong Kong, be subject to the welcome that people are general, threaten and substituting the market on Christmas that existing electricity steeps.

(6) LED product of domestic indoor illumination is more next welcome, LED down, LED Ceiling light, LED daylight lamp, and the fine lamp of LED light enters family stealthily!

(7) led loudspeaker van, started to flow into domestic from 2010.LED moving advertising car (OMDM), Outdoor Mobile Direct Mail advertising is the association product after LED industry is risen.Refer to by LED screen as information output device, mobile vehicle body is as the advertising equipment of heavy body, and self can shift one's position, and generally carries generator, sound equipment, apparatus such as computer, belongs to the one in media.

Developing history

1. 1962, the joint laboratory of GE, Monsanto, IBM have developed gallium arsenide phosphide (GaAsP) semiconducting compound glowed, and from then on visible light emitting diode steps into commercialized development process.

2. nineteen sixty-five, global first item commercialization light emitting diode is born, and it is the LED of the sent infrared light made with germanium material, and unit price is at that time about 45 dollars.Thereafter soon, Monsanto and Hewlett-Packard are proposed the commercialization red LED made of GaAsP material.The efficiency of this LED is every watt of about 0.1 lumen, lower upper more than 100 times than every watt of 15 lumens of general 60 to 100 watts of incandescent lamps.

3. nineteen sixty-eight, the research and development of LED achieve breakthrough, utilize N doping technique to make the efficiency of GaAsP device reach 1 lumens/watt, and can send ruddiness, orange light and sodium yellow.

4. 1971, industry is proposed again the GaP Green Chip LED with same efficiency.

5. to 20 century 70s, due to the extensive application of LED component in family and office equipment, the price plummet of LED.In fact, LED is numeral and text importing technical applications in those epoch leading market.

6. the major technological breakthrough that the eighties is early stage have developed AlGaAsLED, and it can with the luminescence efficiency of every watt of 10 lumens

LED (5) sends ruddiness.This technical progress enables LED be applied to outdoor informational issue and automotive high position brake lamp (CHMSL) equipment.

LED application product chooses points for attention

1. see battery, have common batteries and lithium electricity two kinds, although lithium electricity is rechargeable battery, the life-span is low, about 2 years, in about 10 years life-spans of LED, can select according to actual conditions.High temperature resistant, ageing-resistant, discharge and recharge power-supply battery is often best.

2. see bulb, when bulb extinguishes, naked eyes are difficult to its quality of differentiation, can see the consistance of bulb when lighting.With a paster LED for the best! Optically focused, resistance toly to fall, never fried bulb, far firing range, can reach 100 meters;

3. see aperture, good LED flashlight aperture is a uniform circle, and the LED flashlight hot spot of difference is divided into champac dichromatism uneven distribution.

4. see brightness, good LED flashlight brightness is high, and the rate of decay is slow.Can calculate with lumenmeter.

5. see waterproof, good LED flashlight possesses water-proof function, and anti-seismic performance is good, namely resistance toly falls.

6. see outward appearance, this can be seen than me, and I has not spoken more.What I selected is aluminum alloy casing, elegant in appearance.

Development trend

Illumination consumes and accounts for 20% of whole power consumption, and greatly reducing electric consumption on lighting is the important channel saving the energy, for realizing this

Method for designing and the thinking of conventional light source have been broken in the appearance of LED, have the design concept that two kinds up-to-date.

1. sight illumination: be the sight illumination proposed by Philip for 2008, carry out design lamps with the demand of environment.Sight illumination is starting point with place, and be intended to build a kind of beautiful, gorgeous photoenvironment, go to set off scene effect by contrast, people is felt scene atmosphere.

2. emotional-appeal illumination: be the emotional-appeal illumination proposed by triumphant West Europe for 2009, carry out design lamps with Man's Demands.Emotional-appeal illumination is with people's emotion for starting point, goes to create the photoenvironment as a kind of artistic conception from the angle of people.Emotional-appeal illumination and sight throw light on different, and emotional-appeal illumination is dynamic, can meet the lighting system of the spiritual demand of people, make people feel there is sentiment; And sight illumination is static, it can only emphasize the demand of scene illumination, and can not express the mood of people, and in a sense, emotional-appeal illumination contains sight illumination.Emotional-appeal illumination comprises four aspects: one is environmental protection and energy saving, and two is healthy, and three is intelligent, and four is hommizations.

LED flashlight

This catalogue of relative merits relates to professional domain knowledge, and partial content exists dispute, examines verification by engineering college of Hong Kong University of Science and Thchnology doctoral candidate direction is bright.

The internal characteristics of LED determines it and has lot of advantages, such as:

1, volume is little

LED is that the wafer of a piece very little is encapsulated in inside epoxy resin substantially, so it is very little, very gently.

2, power consumption is low

LED power consumption is quite low, direct drive, and super low-power consumption (single tube 0.03-0.06 watt), electric light power transfer is close to 30%.In general the operating voltage of LED is 2-3.6V, and working current is 0.02-0.03A; In other words, the electric energy that it consumes is no more than 0.1W, equal illumination effect more energy-conservation than conventional light source nearly 80%.

3, long service life

Someone claims LED light source to be long-life lamp.It is solid cold light source, epoxy encapsulation, there is not the shortcomings such as filament light-emitting easily burns, heat deposition, under appropriate electric current and voltage, can reach 6 ten thousand to 10 ten thousand hours serviceable life, than long more than 10 times of conventional light source life-span.

4, high brightness, low in calories

LED uses chemiluminescence technology, and thermal value is more much lower than ordinary luminaire.

5, environmental protection

LED is made by nontoxic material, can pollute containing mercury unlike fluorescent light, and LED also can recycling simultaneously.Do not have ultraviolet and infrared ray in spectrum, both do not have heat, also do not have radiation, dazzle is little, cold light source, can safe touch, belongs to typical green illumination light source

6, sturdy and durable

LED is completely inside epoxy resin, than bulb and fluorescent tube all firm.Also the part do not loosened in lamp body, makes LED not fragile.LED

7, changeable

LED light source can utilize the red, green, blue principle of three primary colours, under computer technology controls, three kinds of colors are made to have 256 grades of gray scales and mixing arbitrarily, 256 × 256 × 256=16777216 kind color can be produced, form different photochromic combination changeful, realize colourful dynamic change effect and various sections of pictures.

8, advanced technology

Compared with the illumination effect of conventional light source dullness, LED light source is low pressure microelectronic product.Its successful fusion computer technology, the network communications technology, section are as treatment technology, embedded Control technology etc., so be also digital information product, be semiconductor photoelectric device " high-new point " technology, there is online programming, infinite update, flexible and changeable feature.

9, comprehensive

Long-life-life-span can more than 100,000 hours, the life-span comparing osram lamp only has 1000 hours, firmly-and there is no moving-member, do not have glass, size-most diameter only has 5 millimeters, electric energy conversion is become luminous energy by the conversion ratio of energy consumption-up to 9 0%, need few electric power supply, environment-protecting asepsis-do not have the toxic heavy metals such as mercury, multi-functional-shades of colour change can be realized, temperature is low-than HID or the less heat radiation of incandescent lamp, and safer under DC low-voltage-some applied field.

Shortcoming

Result shows, and includes antimony, arsenic, chromium, lead and other Determination of multiple metal elements in these LED.Wherein, the toxic element content of part LED has exceeded the standard that supervision department formulates.Such as in low-light level red LED lamp, researchist finds that its lead content exceeds standard and reaches 8 times, and nickel content also exceeds standard 2.5 times.

In fact in California, USA law, most LED is all explicitly defined to toxic refuse, if use the way process of common landfill will contaminated soil and underground water.And if LED is broken, also may cause damage to the health of directly contact.But so far, national governments or the common people know little about it to the environment of LED and health risk.

This report represents, the impact on human body and environment of the arsenic in LED, lead, nickel and copper is the most serious, and future should carry out more careful deep investigation, to promote that government is to the safe handling of LED product and recycling constituting criterion.Briefly, everybody should be clear, although the efficiency of LED is very high, the selection of its complete absolutely not environmental protection, the potential danger just contained is different with other lighting engineering.

Second point LED needs because single light-emitting area is narrow, and usual large-scale integrated in the circuit board, forms a larger light emitting source, amount of heat can be caused thus to accumulate, puncture circuit board sometimes.So the heat radiation of LED necessarily will be got well.Thirdly human eye is least receptible is blue light and UV light (i.e. ultraviolet), the ability that blue light kills and wounds human eye competent cell is 10 times of green glow, and the ability that UV light kills and wounds human eye competent cell is 10 times of blue light, the blue light of a large amount of low wavelength of Long Term Contact can kill and wound human eye competent cell in a large number, and final cancerization forms patch.And LED white light is formed mainly by the blue-light excited fluorescent powder of 450-455NM wavelength, its medium wavelength lower percussion ability is stronger, the wavelength of usual LED dispatches from the factory and controls within 500NM, i.e. 450-455NM, or 455-460NM, belong to the section that injury is the strongest, if wavelength becomes large, so the ability of excitated fluorescent powder just declines, and efficiency reduces.People, in order to pursue brightness, more can strengthen the blue light strength of LED usually, and the lighting time is more of a specified duration, and fluorescent powder decay is faster, and then the illumination of the blue wave band causing human eye to contact is stronger, thus damages human eye.

So LED lamp road traffic LED navigate instruction, LED street lamp, LED desk lamp use on there is certain unfavorable factor, people is easily allowed in use to produce dizzy, uncomfortable sensation, even Long-Time Service can become the fine injury of eye, and the probability had a trouble in one's eyesight can be increased.

Photochromic utilization white light for illumination LED

The spectrum of visible ray and the relation of LED white light.Many weeks, the wavelength coverage of visible light is 380nm ~ 760nm, is the seven-colour-light that human eye can be experienced---red, orange, yellow, green, blue, blue, purple, but all each a kind of monochromatic light naturally of the light of these seven kinds of colors.The peak wavelength of the ruddiness that such as LED sends out is 565nm.White light is not had in the spectrum of visible ray, because white light is not monochromatic light, but by the photosynthetic complex light of multiple monochrome, be by seven kinds of photosynthetic white lights of monochrome as sunshine, and the white light in colour television set is also synthesized by three primary colours red, green, blue.As can be seen here, LED be made to send white light, its spectral characteristic should comprise whole visible spectral range.But manufacturing the LED of this performance, is impossible under the process conditions.According to the research of people to visible ray, the white light that eye can be shown in, at least needs the mixing of two kinds of light, i.e. the pattern of two wavelength luminescences (blue light+sodium yellow) or three wavelength luminescences (blue light+green light+red light).The white light of above-mentioned two kinds of patterns, all needs blue light, so picked-up blue light has become manufacture the gordian technique of white light, i.e. and current Ge great LED manufacturing company " Blue-Ray technology " chased.Grasp the manufacturer of " Blue-Ray technology " in the world and only have several family, so the applying of white light LEDs, especially high-brightness white-light LED also has a process in the popularization of China.

The process structure of white light LEDs and white light source.For general illumination, on process structure, white light LEDs adopts two kinds of methods to be formed usually, and the first utilizes " Blue-Ray technology " to coordinate with fluorescent powder to form white light; The second is multiple monochromatic light mixed method.These two kinds of methods successfully can produce white light parts all.

The application prospect of White-light LED illumination new light sources.In order to the feature of white light LEDs is described, first look at the situation of illuminating lamp light source used.Incandescent lamp and halogen tungsten lamp, its light efficiency is 12 ~ 24 lumens/watt; The light efficiency of fluorescent light and HID lamp is 50 ~ 120 lumens/watt.To white light LEDs: in 1998, the light efficiency of white light LEDs only has 5 lumens/watt, has reached 15 lumens/watt by 1999, this index is close with general family expenses incandescent lamp, and 2000 time, the light efficiency of white light LEDs has reached 25 lumens/watt, this index is close with halogen tungsten lamp.2012, the light efficiency of white light LEDs reached 120 lumens/watt, and white light LEDs is made family expenses lighting source and started to popularize.When expecting the year two thousand twenty, the light efficiency of LED is expected to reach 200 lumens/watt.

Though the incandescent lamp of general lighting and halogen tungsten lamp low price, light efficiency low (the thermal effect power consumption in vain of lamp), the life-span is short, maintenance workload is large, if but throw light on white light LEDs, not only light efficiency is high, and the life-span long (stream time more than 10000 hours), almost Maintenance free.Hella company of Germany utilizes white light LEDs to develop aircraft reading lamp; The a street in Australia Canberra, capital has used white light LEDs to make street lighting; The urban traffic control lamp of China also just replaces early stage traffic order pilot lamp with white light LEDs.Can predict in the near future, white light LEDs surely can enter family and replace existing illuminating lamp.

LED light source have use low-tension supply, power consumption less, applicability is strong, stability is high, the response time is short, environmentally safe, multicolor luminous etc. advantage, although the more existing illuminating equipment of price is expensive, is still considered to it and incites somebody to action inevitably existing illuminating device.

Brightness adjustment control

Traditionally, the light modulation of LED utilizes a DC signal or filtrate PWM to regulate the forward current in LED.Reduce LED current and will play the effect regulating LED light output intensity, but the change of forward current also can change the colour of LED, because the colourity of LED can change along with the change of electric current.Many application (such as automobile and LCD TV back lighting) all can not allow LED that any color drift occurs.In such applications, owing to there is different light changes in surrounding environment, and human eye is all very sensitive for the subtle change of light intensity, and therefore wide region light modulation is required.The way controlling LED luminance by applying a pwm signal allows the light modulation completing LED when not changing colour.

Real colour (True Color) the PWM light modulation that it has often been said utilizes a pwm signal to regulate the brightness of LED.

LED luminance is regulated to have three kinds of common methods:

(1) SET resistance is used, the transfer resistance in parallel different at LED drived control IC pin RSET two ends, use a DC voltage that the electric current of LED drived control IC pin RSET is set, thus change the forward working current of LED, reach the object regulating ALED luminosity.

(2) adopt PWM technology, utilize pwm control signal, regulated the luminosity of ALED by the dutycycle of the forward working current of control LED.

(3) linear regulation, the easiest method is in LED drived control C, use outside SET resistance to realize the brightness adjustment control of LED.Although this dimming controlling method is effective, lacks dirigibility, user cannot be allowed to change light intensity.Linear regulation then can lower efficiency, and causes white light LEDs towards the color offset of yellow spectrum.May be slight skew, but can detect in sensitive application.

Adopt numeral or cry the LED brightness adjustment control method of PWM to be greater than the switch operating frequency of 100HZ, the pulse duty factor changing LED drive current with the method for width modulation carrys out real brightness adjustment control of managing LED, select and be greater than 100HZ switch dimming controlled frequency mainly in order to avoid human eye perceives is to light modulation scintillation, under the PWM brightness adjustment control of LED, the luminosity of LED is proportional to the pulse duty factor of PWM, under this dimming controlling method, can be more constant than keeping the glow color of LED in scope in height light modulation, adopt the light modulation of the LED brightness adjustment control of PWM can reach 3000:1 than scope.

Linear LED dimming controlling method adopts simulation dimming controlling method exactly, and under simulation brightness adjustment control, by the brightness adjustment control regulating the forward working current of LED to realize LED, brightness adjustment control scope can reach 10:1.

If the forward working current of LED will be reduced further, LED glow color can be produced and to change and can not the problem of the accurate forward working current of regulable control LED.

The general modal LED operating power of parameter efficiency is all be set in below 30 to 60 milliwatt electric energy.Started in 1999 to introduce the business grade LED that can use continuously under 1 watt of electric power input.These LED process the problem of high electric energy input with especially big semi-conductor chip, and that semi-conductor chip is all be fixed on metal iron plate, to help heat radiation.In 2002, commercially start the appearance of the LED having 5 watts, and its efficiency is approximately every watt 18 to 22 lumen.

In September, 2003, Cree, Inc. company illustrates its trendy blue-ray LED, is issued to the illumination efficiency of 35% at 20 milliamperes.They have also manufactured a white light LEDs commodity reaching 65 lumen every watt, and this is white light LEDs the brightest on market at that time.They show a white light LEDs prototype in 2005, under 350 milliamperes of working environments, create the record efficiency of every watt of 70 lumens.

Today, the work efficiency of OLED is much lower compared with general LED, and the highest is all about 10%.But the production cost of OLED is much lower, such as, especially big OLED array can be placed on screen, in order to manufacture colorful display screen with simple printing method.

The measurement of light intensity

The measuring distance that CIE defines luminous intensity has two kinds: far field (condition A) is 316mm, and corresponding solid angle is 01001Sr; Near field (condition B) is 100mm, and corresponding solid angle is 0101Sr: can mutually change between the two, far-field measurement result is multiplied by 10 and just obtains near field measurement result.

The measuring distance that IEC specifies is only near field (condition B), solid angle < 0101Sr.

To measuring distance, the sensitive face of CIE clear stipulaties from the housing top end of LED to photo-detector.And IEC specifies fuzzyyer.

Comment: surface seems, sometimes uncertainty is little than near field measurement for far-field measurement because with this understanding to measuring distance, electric current can be relative lower with the requirement of parasitic light.But meanwhile, the impact of LED mounted angle but increases relatively, this is a big error source.Generally speaking, the applicable strong illumination of far field condition and encapsulating products, and Near Field is applicable to weak illumination and chip, pilot lamp and backlight etc.Therefore all have the necessity of existence.Secondly, CIE is logically rigorous not.

First, it describes LED with very large length is not pointolite, therefore square distance law of reciprocity is false, and this concept of luminous intensity is also inapplicable.In addition in practice, it is actually measures the illumination of LED in photodetector sensitive face, be then multiplied by distance square and obtain luminous intensity.

Like this, the square distance law of reciprocity be once denied in fact still has been used.Briefly be divided into: synchronous control system (with computer export content synchronization); Asynchronous off line control system (content being stored in control card, offline operation)

Along with the develop rapidly of nearly 2 years LED display, it is more wide that the market of LED control system also becomes, especially the just new Victor USB flash disk LED control card use risen in 09 year is maximum, Victor USB flash disk LED control card can connect computer with serial ports, also USB flash disk transmission of information can be used, economize computer, exempt from wiring, support simulated clock simulation clock, flowing water frame, Victor USB flash disk LED control card is applicable to various indoor and outdoor display screen, has deeply liked by LED display manufacturer in all parts of the country since listing.LED control card

LED display develops into the present and progressively enters into civil nature, and the door head as various StoreFront shields, the various square screen of indoor and outdoor and other various stripe shape screens etc.Join display screen must connect a computer and carry out update content, this make greatly user particularly advertising user upgrade program difficulty.USB flash disk LED control card solves this difficult problem, use this common and the most inexpensive information transmission media instrument of USB flash disk, go to upgrade screen content even if user does not have computer can finish content by the computer of Internet bar, family or friend yet, USB flash disk does not need to be inserted on display screen or its extended line always, after plugging rear a few second, information is just stored in screen, and USB flash disk just can pull out away.USB flash disk LED control card has conventional serial communication function, wants directly to connect use with the user of computer Direct Communication.Transmit LED display content with USB flash disk, and be progressively applied in LED display in all parts of the country.

LED display control card, also known as LED nonsynchronous controller, is the core component of LED segment literary composition display screen.Be responsible for receiving the picture display information from computing machine serial port, insert frame memory, by the series display data needed for subregion type of drive generation LED display and scan control sequential.

LED display is to show various word, symbol and section shape.Picture display information, by Computerized Editing, is inserted the frame memory of LED display in advance, is then displayed the play by screen, move in circles through RS232/485 serial port.Display mode is rich and varied, display screen off-line working.LED display controls flexibly because of it, easy to operate, with low cost, has a wide range of applications in social every profession and trade.

Problem development obstacles

One, domestic enterprise's coreless

Most core patents of the upstream of LED industry grasp by external manufacturer.We do not grasp core technology, although our LED application product manufacturing capacity accounts for 50% in the whole world, share accounts for 50%, and profit is a minimum ring.

LED chip adopts more large scale wafer manufacture craft with technique, quantity growth, constantly can reduce costs, reduce, in LED chip cost factor in 20% speed every year, the lifting of light efficiency also will be counted in price reduction, same price have purchased better product.The cost of LED illumination lamp is mainly at LED chip, as long as chip price lowers, the lumen unit price of LED can drop to the electricity-saving lamp of present stage suitable, and room lighting is just naturally in full flourish.LED chip also has room for price-cut greatly.

Two, the heat radiation of LED application product is difficult

Structural design probably accounts for 20% in light fixture, and the people that China is industrious all the time can fix a price very low, and 20% cost thinks quite reasonable, and maximum problem how more to have innovation, and it is more reasonable to design.

Heat radiation cost will maintain 5%, and actual heat dissipation design is very simple, holds both direction: one is, LED chip and outer radiating element path more short better, your heat dissipation design shorter is better; Two are, heat radiation resistance, and enough heat radiation conducting paths be had also will to have enough ' heat radiation road ' simultaneously. this part cost is mainly in structure, also few for the cost that dispels the heat.

Three, LED applied power source management

Power supply is the link that LED lamp is the weakest, and serious delayed LED lamp development, quality has much room for improvement.Design accounts for about 20% of light fixture cost, and some is high.Along with technical development power supply is probably reasonable at 5-10%.

LED cost is high, is relative other light sources in fact, and as the just invention blue-ray LED nineties in 20th century, thus cause the LED industry that LED white light is achieved, LED manufacturing cost is not high in fact.Especially LED environmental protection, energy-conservation, not mercurous, and the price of quarterly LED lamp is all sliding down, and believes the level that necessarily can reach people in the short period of time and can accept.According to the electricity consumption rule of electrical network and the characteristic requirements of LED drive power, to consider that when Choice and design LED drive power following nine large performance characteristics require:

1. the driving power of high reliability special picture LED street lamp, is contained in high-altitude, and maintenance is inconvenient, and the cost of maintenance is also large.

2. high-level efficiency LED is energy-conserving product [3], and the efficiency of driving power wants high.Power supply is arranged on to the structure in light fixture, particularly important.Because the luminescence efficiency of LED declines, so the heat radiation of LED is extremely important along with the rising of LED temperature.The efficiency of power supply is high, and its dissipation power is little, just little in light fixture internal heat generation amount, also just reduces the temperature rise of light fixture.Favourable to the light decay delaying LED.

3. high power factor power factor (PF) is the requirement of electrical network to load.The electrical appliance of general less than 70 watts, does not have compulsory index.Although the little lower impact on electrical network of single electrical appliance power factor (PF) of power is little, lighting in evening, similar load is too concentrated, can produce more serious pollution to electrical network.For the LED drive power of 30 watts ~ 40 watts, it is said in the near future, perhaps can have certain index request to power factor (PF) aspect.

4. what type of drive was current has two kinds: first constant pressure source is for multiple constant current source, and each constant current source powers to separately every paths of LEDs.This mode, flexibly, a paths of LEDs fault, does not affect the work of other LED, but cost can omit height a bit in combination.Another kind is direct constant current-supplying, LED strip connection or parallel running.Its advantage is that cost is lower, but very flexible, also to solve certain LED fault, not affect the problem that other LED run.This two kinds of forms, deposit within a period of time.Multiple constant current exports power supply mode, can be better at cost and aspect of performance.Perhaps be later main flow direction.

5. the ability of surge protection LED antisurge is poor, and particularly anti-reflective is to voltage capability.The protection strengthening this respect is also very important.Some LED is contained in open air, as LED street lamp.Open the induction of getting rid of and being struck by lightning due to network load, can invade various surge from network system, some surge can cause the damage of LED.Therefore LED drive power will have the intrusion suppressing surge, the not impaired ability of protection LED.

6. defencive function power supply is except the defencive function of routine, in constant current output, preferably increase the negative feedback of LED temperature, prevents LED temperature too high.

7. the outer mount type of protection aspect light fixture, power supply architecture wants waterproof, protection against the tide, and shell wants sun-proof.

8. the life-span of driving power is suitable with the life-span of LED.

9. to meet the requirement of safety and electromagnetic compatibility.

Along with the application of LED is increasingly extensive, the performance of LED drive power will more and more be applicable to the requirement of LED.

Problems faced

Promote upgrading of the industrial structure in country, cultivate new this strategic task of industry growth point guidance under, LED becomes the development priority of each place government, the local governments such as Dongguan, Huizhou, Foshan, Shenzhen, Dalian, Nanchang, Xiamen have formulated strategy of industrial development planning one after another, have domesticly started one LED investment tide.As the Guangdong of nearly half of the country occupying the domestic LED gross output value, in " the some suggestions changed about the mode of accelerating economic development " issued May, semiconductor lighting (LED) industry is classified as one of three great strategy new industries that Guangdong emphasis mainlys grasp.LED industry has defined the situation of all the competitors strive to be the best in Guangdong.LED industry is all classified as column support type industry development by Shenzhen, Dongguan, Foshan.LED industry has presented the gesture of being on the upgrade everywhere.

Domestic LED enterprise emerges rapidly and enhances production capacities rapidly, for attack strategy is launched in contention LED market.Pacify photoelectricity from domestic LED industry leading enterprise three to reach to the moral person of outstanding talent profit of switching to a job one was not trained for again to the Silan expanding production capacity is micro-, LED industry upsurge has almost swept across whole industry, because domestic LED product technology integral level is not high, the general small scale of domestic enterprise, technical strength are weak, product specification is also lower, LED Market competition, relevant manufactures is striven and is carried out feverish price war, and has also occurred the phenomenons such as unordered investment, harmful competition in LED industry simultaneously.From home market, there is the problem of very serious overlapping investment in dynamic and LED industry structure distribution.

In addition, local market opens to local manufacturing enterprises intentionally by some local governments in developing the economy, or pins local market to invest the mode of changing market, and local protectionism has new line trend.If do not break this district administration barrier, the industry project between area must be brought convergent, direct increasing industry foam, hinder regional integration development process.Zones of different will give prominence to different characteristic, avoid, into the simple duplicate construction of short-term interests, causing following harmful competition.

In addition, also there is a series of other problem in the LED illumination of China, such as China does not also have LED lamp national standard, only has the standard in some places; The obvious deficiency of China's native country LED lamp Shape Creative Design ability etc.Resolve these problems, LED industry just can be made to develop more healthy, LED product more could adapt to popular needs.Leading market be LED illumination industry can long-term health development basis, government will guide in many-sides such as policy, regulation, Innovation Input, Applied D emonstration and standards and help, and take the whole country into account, integrated planning, could guide LED industry sustainable and healthy development.

Application problem

1, heat dissipation problem.Although LED is energy-conservation, but it is the same with general incandescent lamp decoration, part energy is converted into other part energy in the process of light and changes into heat, especially LED is point-like illuminating source, its heat produced also concentrates on minimum region, if the heat produced cannot distribute in time, the junction temperature of PE knot will raise, speed-up chip and potting resin aging, solder joint also may be caused to melt, make chip failure, and then the serviceable life directly affecting LED shows with luminous, especially great power LED, its thermal value is larger, require higher to heat dissipation technology.Can say that heat dissipation problem is directly connected to the development prospect of LED.Therefore will promote the heat-sinking capability of LED product, crucial being also finds a kind of radiating mode can accelerating to be taken away fast by lamp surface heat.

2, photochromic problem.The light that LED sends still has a certain distance compared with natural light, and natural light has very strong yellow spectrum composition, to a kind of warm sensation of people.And the white light that LED sends is with more blue light ingredient, under the illumination of this light, the visual experience of people is not very natural, and the light ratio that LED sends comparatively is dazzle the eyes, and easily causes dazzle.

3, selling at exorbitant prices.Current about 4 times of remaining conventional lamp price with isolux LED lamp price, this remains a larger obstacle to popularizing of LED.

Encapsulation technology 1. expands crystalline substance: the thickly dotted wafer of arrangement is removed any and is convenient to die bond.

2. die bond: (whether conduct electricity depending on wafer is upper and lower LED workshop to conduction/nonconducting glue on frame bottom point

Type PN junction or left right model PN junction and determine) then wafer is put into inside support.

3. short roasting: allow glue curing bonding wire time wafer do not move.

4. bonding wire: with gold thread wafer and support conducting.

5. before measurement: preliminary test can be bright.

6. encapsulating: chip and support are wrapped up with glue.

7. long roasting: to allow glue curing.

8. survey after: whether bright test energy is and whether electrical parameter is up to standard.

9. color-division branches away product consistent haply with voltage for color.

10. pack.

Since mechanics of communication high-capacity LED is about to the main force becoming solid-state illumination of future generation (SSL), electronic industry circle has also appeared more bold new thinking in one's mind.Namely give up close-packed radio frequency width, speed of using instead is difficult to the LED switching mode of identification to transmit data near human eye, and such mode is just called LED visible light communication (VLC).Through the technical support of advanced person, each new LED lamp can access backbone network in a wired fashion, makes can realize immanent wireless telecommunications between distinct device, and can not increase the burden of existing radio frequency width.This LED visible light communication transfer technology many employings white light LEDs, because white light LEDs feature is rapid reaction, can as the basis of visible ray mechanics of communication.LED visible light transmission technology utilizes the interior illumination fixture such as fluorescent lamp or white light LEDs, sends the high speed light and shade flicker signal that naked eyes cannot be discovered, wirelessly carry out data transmission.Adopt visible ray to be because its wavelength coverage is large, can pass through design and visible ray signal is transmitted through different wave length.And research staff also to test Different lightwave long, utilize the different color forming white light, many data streams carried out to the research and development of encoded content.

The advantage of LED visible light mechanics of communication, can avoid the electromagnetic wave of general WLAN or high frequency wireless transmission at what, human body and periphery electronic equipment are caused to the impact of interference, and can replace radio base station, possess the feature that security is high simultaneously.Industry, normal structure, or the plan obtaining government-funded all starts to research and develop LED visible light communication, and its prospect is extremely expected.Only the scale in traditional lighting market just reaches several million dollars after all, is transitioned into solid-state illumination market future, and its business opportunity is very considerable.

Important parameter forward working current If

Forward current value when it refers to light-emittingdiode normal luminous.Should IF be selected as required at below 0.6IFm in actual use.

Forward operating voltage VF

The operating voltage provided in parameter list obtains under given forward current.Generally record when IF=20mA.Light-emittingdiode forward operating voltage VF is at 1.4 ~ 3V.When ambient temperature raises, VF will decline.

V-I characteristic

The voltage of light-emittingdiode and the relation of electric current, when forward voltage is just being less than a certain value (being threshold value), electric current is minimum, not luminous.After voltage exceedes a certain value, forward current increases sharply with voltage, luminous.

Luminous intensity IV

The luminous intensity of light-emittingdiode typically refers to the luminous intensity on normal (referring to its axis to cylindrical luminotron) direction.If when radiation intensity is (1/683) W/sr in the direction in which, then luminous 1 candela (symbol is cd).Because the luminous intensity of general LED is little, so luminous intensity commonly uses candle light (candela, mcd) office.

The lighting angle of LED

-90°- +90°

Spectral half width Δ λ

It represents the spectral purity of luminotron.

Half-value angle and visual angle

θ 1/2 refers to that luminous intensity values is the direction of axial strength value half and the light-emitting axis angle to (normal direction).

Holotype

According to the angle that LED light-emitting 3 D angle converses, be also plane angle.

Visual angle

Refer to the maximum angle of LED luminescence, different according to visual angle, application is also different, also cries light intensity angle.

Half shape

Angle between normal direction 0 ° and maximum emission intensity value/2.Strict upper, be maximum emission intensity value and the angle corresponding to maximum emission intensity value/2.The encapsulation technology of LED causes maximum lighting angle to be not the light intensity value of normal direction 0 °, introduces deviation angle, refers to be angle between angle corresponding to maximum emission intensity and normal direction 0 °.

Forward current IFm

Allow the maximum DC Forward Current added.Exceed this value and can damage diode.

Reverse voltage VRm

Allow the inverse peak voltage that adds.Exceed this value, light-emittingdiode may breakdown damage.

Working environment topm

The ambient temperature range that light-emittingdiode can normally work.Below or above this temperature range, light-emittingdiode is by cisco unity malfunction, and efficiency reduces greatly.

Allow power consumption Pm

Allow the long-pending maximal value of the electric current being added on LED two ends forward dc voltage and flowing through it.Exceed this value, LED heating, damage.

Welding requirements 1, must wear antistatic gloves, antistatic wrist strap when producing, electric soldering iron must ground connection, forbids two terminal pins of free-hand touch white light LEDs.Because the electrostatic prevention of white light LEDs is 100V, and when working relative humidity is 60%-90% on the table, the electrostatic of human body can damage the crystallizing layer of light-emittingdiode, after work a period of time, (as 10 hours) diode will lose efficacy (not working), can lose efficacy immediately time serious.

2, welding temperature is 260 DEG C, 3 seconds.Temperature is too high, and overlong time can burn out chip.In order to protect LED better, LED colloid and PC plate should keep the spacing of more than 2mm, and to make, welding heat is loose in pin to be removed.

3, the running current of LED is 20mA, and the minor fluctuations (as 0.1V) of voltage all will cause fluctuate widely (10%-15%) of electric current.Therefore, different current-limiting resistances should be matched according to the pressure drop of LED, to ensure that LED is in optimum Working when circuit design.Electric current is excessive, and LED can shorten the life-span, and electric current is too small, does not reach required light intensity.General can by LED color-division when volume shipment, namely strong, the voltage of same LED light of contracting for fixed output quotas in product, photochromic all yes, and to indicate on light splitting color table.

4, LED lens filling gel process

(1) substrate surface should clean drying.The moisture of heat abstraction substrate surface can be added; Naphtha, methyl ethyl ketone oxime (MEK) or other suitable solvent cleaning substrate surface can be used.Should not use and have to base material the solvent dissolving or corrode, should not use residual solvent.

(2) according to blending ratio---A:B=1:1(weight ratio of recommending), precise in clean glass container, and fully mixes.When using mixing plant mixing at a high speed, the heat that high-speed stirred produces likely makes the temperature of glue raise, thus shortens service time.

(3) under the vacuum of 10mmHg, bubble is deviate from.Generally before distribution encapsulating material, deviate from bubble.Also the program of de-bubbled can be increased as required after dispensing.

(4) for ensureing the operability of sizing material, be please finished in 60 minutes after A, B mixing.

(5) Best Curing is solidify at 25 DEG C, within 3-4 hour, starts solidification, solidifies needs 24 hours completely; Also can in 50 DEG C of heating 60min solidification.When solidification temperature is lower than 25 DEG C, proper extension set time or raising solidification temperature contribute to the solidification completely of product.

Industrial chain LED industry chain roughly can be divided into five parts.One, starting material.Two, LED upstream industry, mainly comprises epitaxial material and chip manufacturing.Three, LED middle reaches industry, mainly comprises various LED component and encapsulation.Four, LED downstream industry, mainly comprises the application product industry of various LED.Five, testing tool and production equipment.

About LED upstream, midstream and downstream industry, detailed introduction will be had below to introduce starting material industry and testing tool and production equipment industry here.Light emitting diode is referred to as LED.The diode be made up with the compound of arsenic (AS), phosphorus (P) of gallium (Ga), can give off visible ray when electronics and hole-recombination, thus can be used for making light emitting diode.As pilot lamp in circuit and instrument, or form word or numerical monitor.Gallium arsenide phosphide diode glows, gallium phosphide diode green light, silicon carbide diode Yellow light-emitting low temperature.

History light emitting diode (English: Light-Emitting Diode is called for short LED) is a kind of semiconductor electronic component that can be luminous.This electronic component early

Occurred in 1962, can only send the ruddiness of low luminosity in early days, develop other monochromatic versions afterwards, the light that can send even to this day is throughout visible ray, infrared ray and ultraviolet, and luminosity also brings up to suitable luminosity.And purposes is also by the beginning as pilot lamp, display board etc.; Along with the appearance of white light emitting diode, continuous being gradually developed to is used as illumination.

LED can only toward a direction conducting (energising), be called forward bias (forward bias), when the current flows, electronics and hole compound and send monochromatic light within it, this is electroluminescent effect, and the wavelength of light, color are relevant with the element impurity of mixing with its semiconductor material kind adopted.Have that efficiency is high, the life-span be long, advantage that conventional light source such as high, the high reliability of cracky, switching speed is not too late.The luminescence efficiency of white light LEDs, has had obvious lifting in recent years, meanwhile, in the buying price of every kilolumen, also because of the impact that the manufacturer put goods on the market vies each other, and obviously declines.Although more and more people uses LED illumination to make office, furniture, decoration, signboard even street lamp purposes, technically, LED in photoelectric transformation efficiency (Effective Illuminance is to the ratio of power consumption) still lower than novel fluorescent light.

Brief introduction light emitting diode

It is the one of semiconductor diode, electric energy conversion can be become luminous energy; Often be abbreviated as LED.Light emitting diode is the same with general-purpose diode to be made up of a PN junction, also has unilateral conduction.After adding forward voltage to light emitting diode, be injected into the hole in N district from P district and be injected into the electronics in P district by N district, near PN junction in several microns respectively with the electronics in N district and the hole-recombination in P district, produce the fluorescence of spontaneous radiation.In different semiconductor materials, electronics is different with the energy state residing for hole.The amount discharged when electronics and hole-recombination is different, and the energy discharged is more, then the wavelength of the light sent is shorter.Conventional is glows, the diode of green glow or gold-tinted.

The breakdown reverse voltage of light emitting diode about 5 volts.Its forward volt-ampere characteristic is very steep, and during use, necessary series limiting resistor is to control the electric current by pipe.Current-limiting resistance R can calculate with following formula:

Computing method R=(E-UF)/IF

In formula, E is supply voltage, and UF is the forward voltage drop of LED, and IF is the general work galvanoluminescence diode of LED

One longer in two lead-in wires of physical characteristics light emitting diode is positive pole, should connect positive source.Two of some light emitting diodes go between equally long, but shell have the uvula of a projection, and the lead-in wire near uvula is positive pole.Light emitting diode

Steep with small filament lamp and compare with neon lamp, the feature of light emitting diode is: operating voltage very low (more several volts had); Working current very little (the only zero point several milliamperes had can be luminous); Shock resistance and anti-seismic performance good, reliability is high, and the life-span is long; Can the power of modulated luminescence easily by modulating that the electric current that passes through is strong and weak.Owing to there being these features, light emitting diode is used as light source in some photoelectric control equipments, in many electronic equipments, be used as Signal Monitor.Its die is done into strips, forms 7 segmentation semiconductors with the luminotron of 7 strips, each charactron can show 0 ~ 90 figure.

Principle of luminosity before 50 years people understood the ABC that semiconductor material can produce light, first commercial diode results from nineteen sixty.LED is English light emitting diode(light emitting diode) abbreviation,

Light emitting diode

Its basic structure is one block of electroluminescent semiconductor material, is placed on a leaded shelf, then surrounding epoxy sealing, plays the effect of protection internal core, so the anti-seismic performance of LED is good.

The wafer that the core of light emitting diode is made up of P-type semiconductor and N-type semiconductor, has a transition bed, is called PN junction between P-type semiconductor and N-type semiconductor.In the PN junction of some semiconductor material, the minority carrier of injection and majority carrier compound tense can discharge unnecessary energy in the form of light, thus electric energy is directly converted to luminous energy.PN junction adds reverse voltage, and minority carrier is difficult to inject, therefore not luminous.This diode utilizing injection electroluminescence principle to make, light emitting diode, is generally called LED.When it is in forward duty (two ends add forward voltage), when electric current flows to negative electrode from LED anode, semiconductor crystal just sends the light from ultraviolet to infrared different colours, the power of light and current related.

Be below the inorganic semiconductor material that uses of conventional light emitting diodes and the color of their luminescences

Aluminum gallium arsenide (AlGaAs)-redness and infrared ray

Aluminum gallium phosphide (AlGaP)-green

The Chinese red of AlGaInP (AlGaInP)-high brightness, orange, yellow, green

Gallium arsenide phosphide (GaAsP)-redness, Chinese red, yellow

Gallium phosphide (GaP)-redness, yellow, green

Gallium nitride (GaN)-green, emerald green, blue

Indium gallium nitride (InGaN)-near ultraviolet ray, blue-green, blue

Silit (SiC) (as substrate)-blue

Silicon (Si) (as substrate)-blue (in exploitation)

Sapphire (Al2O3) (as substrate)-blue

Zincselenide (ZnSe)-blueness

Diamond (C)-ultraviolet

Aluminium nitride (AlN), aluminiumgalliumnitride (AlGaN)-wavelength is as far as near ultraviolet

Classification light emitting diode also can be divided into normal monochrome light emitting diode, high brightness LED, super brightness emitting LED

Diode, color-changing light-emitting diode, blinking light emitting diode, voltage-controlled type light emitting diode, infrarede emitting diode and negative resistance light emitting diode etc.

Normal monochrome light emitting diode

Normal monochrome light emitting diode has the advantages such as volume is little, operating voltage is low, working current is little, luminescence is uniform and stable, fast response time, life-span length, and the power drives such as available various direct current, interchange, pulse are lighted.It belongs to electric current controlling semiconductor device, need be connected in series suitable current-limiting resistance during use.

The glow color of normal monochrome light emitting diode is relevant with luminous wavelength, and the wavelength of luminescence depends on light emitting diode processed

Make the semiconductor material that light emitting diode is used.The wavelength of red light emitting diodes is generally 650 ~ 700nm, the wavelength of amber light emitting diode is generally 630 ~ 650 nm, the wavelength of orange luminescence diode is generally about 610 ~ 630 nm, the wavelength of yellow light-emitting diode is generally about 585 nm, and the wavelength of green LED is generally 555 ~ 570 nm.The domestic normal monochrome light emitting diode commonly used has BT(emblem mark model) serial, FG(portion mark model) serial and 2EF series, in Table 4-26, show 4-27 and show 4-28.

Conventional import normal monochrome light emitting diode has SLR series and SLC series etc.

High brightness single color LED

The semiconductor material that high brightness single color LED uses with super brightness single color LED is different from normal monochrome light emitting diode, so the intensity of luminescence is also different.

Usually, high brightness single color LED uses the materials such as arsenic calorize gallium (GaAlAs), super brightness single color LED uses the materials such as phosphorus indium gallium arsenide (GaAsInP), and normal monochrome light emitting diode uses the materials such as gallium phosphide (GaP) or gallium arsenide phosphide (GaAsP).

The major parameter of conventional High brightness Red LED is in Table 4-29, and the major parameter of conventional super brightness single color LED is in Table 4-30.

Color-changing light-emitting diode

Color-changing light-emitting diode is the light emitting diode that can convert glow color.Color-changing light-emitting LED lighting color category can be divided into dichromatic LED, Tricolor LED and polychrome (having red, blue, green, Bai Si kind color) light emitting diode.

Color-changing light-emitting diode can be divided into two end color-changing light-emitting diodes, three end color-changing light-emitting diodes, four end color-changing light-emitting diodes and six end color-changing light-emitting diodes by pin number.

Conventional dichromatic LED has 2EF series and TB series, and conventional Tricolor LED has the models such as 2EF302,2EF312,2EF322.

Blinking light emitting diode

Blinking light emitting diode (BTS) is a kind of special luminescent device be made up of CMOS integrated circuit and light emitting diode, can be used for report to the police instruction and under-voltage, superpressure instruction.

Blinking light emitting diode in use, need not other element external, as long as add that at its pin two ends suitable direct-current working volts (5V) get final product flashing.

Voltage-controlled type light emitting diode

Common light emitting diode belongs to current control device, needs the current-limiting resistance being connected in series suitable resistance in use.Voltage-controlled type light emitting diode (BTV) be by light emitting diode and current-limiting resistance integrated be made as one, directly can be attempted by both ends of power during use.

Infrarede emitting diode

Infrarede emitting diode also claims infrared light emitting diode, and it electric energy can be directly changed into infrared light (invisible light) and the luminescent device that can radiate, and is mainly used in various light-operated and remote controlled transmitting circuit.

Structure, the principle of infrarede emitting diode are close with common light emitting diode, and the semiconductor material just used is different.Infrarede emitting diode uses the material such as gallium arsenide (GaAs), arsenic calorize gallium (GaAlAs) usually, adopts all-transparent or resin-encapsulated that is light blue, black.

Conventional infrarede emitting diode has SIR series, SIM is serial, PLT is serial, GL is serial, HIR is serial and HG is serial etc.

The blue-ray LED that LED is formed with GaN 1993, the Shuji Nakamura (ShujiNakamura) worked at Japanese NichiaCorporation (day sub-chemical industry) has at that time invented the blue-ray LED with commercial application value of sowing (InGaN) based on semiconductor material with wide forbidden band gallium nitride (GaN) and indium nitrogenize, and this kind of LED was used widely in the later stage in the 1990's.Blue-ray LED can produce white light in conjunction with original red-light LED and green light LED in theory, but white light LEDs is created seldom like this.

The white light LEDs major part of current production is that this yellow phosphor normally passes through the YttriumAlum mixing cerium by making at the upper faint yellow fluorescent coating of one deck that covers of blue-ray LED (near-UV, wavelength 450nm to 470nm)

Light emitting diode

InumGarnet (Ce3+:YAG) crystal is mixed in a kind of dense binder after claying into power and makes.When LED chip sends blue light, some blue light just can be converted to the light being mainly yellow of a spectrum wider (spectral centroid is about 580nm) very efficiently by this crystal.(in fact the YAG mixing Ce of monocrystalline is regarded as scintillater more than phosphor.) ruddiness in naked eyes and green glow acceptor can be stimulated due to gold-tinted, then mix the blue light of LED itself, make it seem just as white light, and its color and luster is often referred to as " white of moonlight ".The method of this making white light LEDs is developed by NichiaCorporation and was used in from 1996 to produce on white light LEDs.To the color of the yellowish coloured light of adjustment, other rare earth metal Tb available or gadolinium replace the cerium (Ce) mixed in Ce3+:YAG, even can accomplish in the mode replacing part in YAG or whole aluminium.And based on the characteristic of its spectrum, red and green object seems under this LED illumination can not as good as so distinct during wealthy spectrum light source irradiation.

In addition due to the variation of working condition, the colour temperature of the finished product of this LED disunity, having to cold blueness from warm yellow, so can make differentiation with its characteristic out in process of production.

The method of another white light LEDs made is then a little as daylight lamp, the LED sending black light can be coated with the potpourri of two kinds of phosphors, be glow and the europium of blue light, another kind is green light, is doped with copper and the aluminium of zinc sulphide (ZnS).But because ultraviolet can make the epoxy resin cracking in binder go bad, so production difficulty is higher, and the life-span is also shorter.Compare with first method, its efficiency is lower and produce more heat (because StokesShift the former larger), but benefit to be the characteristic of spectrum better, the light of generation is good-looking.And due to the LED power of ultraviolet light higher, though so its efficiency to compare first method low, brightness is out similar.

A kind of up-to-date method manufacturing white light LEDs does not use phosphor again.New way is the epitaxial layer at zinc selenide (ZnSe) grown on substrates zinc selenide.During energising its enliven area can send blue light and substrate can Yellow light-emitting low temperature, mixing is white light.

Method for designing and the thinking of conventional light source have been broken in the appearance of design concept LED, have the design concept that two kinds up-to-date at present.

1. sight illumination

Carry out design lamps with the demand of environment.Sight illumination is starting point with place, and be intended to build a kind of beautiful, gorgeous photoenvironment, go to set off scene effect by contrast, people is felt scene atmosphere.

2. emotional-appeal illumination

Carry out design lamps with Man's Demands.Emotional-appeal illumination is with people's emotion for starting point, goes to create the photoenvironment as a kind of artistic conception from the angle of people.Emotional-appeal illumination and sight throw light on different, and emotional-appeal illumination is dynamic, can meet the lighting system of the spiritual demand of people, make people feel there is sentiment; And sight illumination is static, it can only emphasize the demand of scene illumination, and can not express the mood of people, and in a sense, emotional-appeal illumination contains sight illumination.

Light source feature voltage

LED uses low-tension supply, and supply voltage is between 6-24V, different according to product difference, so it is the power supply that a ratio uses high-voltage power supply safer, is specially adapted to public place.Light emitting diode

Usefulness

Consumed energy comparatively reduces 80% with the incandescent lamp of light efficiency

Applicability

Volume is very little, and each unit LEDs small pieces are squares of 3-5mm, so can be prepared into the device of various shape, and is suitable for variable environment

Stability

100000 hours, light decay was initial 50%

Response time

The response time of its incandescent lamp is Millisecond, and the response time of LED is nanosecond

Environmental pollution

Without poisonous metal mercury

Color

Light emitting diode is conveniently by chemical modification method, and the band structure of adjustment material and energy gap, realize red, yellow, green and blue orange multicolor luminous.Ruddiness pipe operating voltage is less, and the operating voltage of red, orange, yellow, green, the blue light emitting diode that color is different raises successively.

Price

The price of LED is more and more popular, because of the characteristic of LED power saving, perhaps in the near future, people all can incandescent lamp is changed into LED.The places such as China's urban highway, school, plant area have changed the outfit LED street lamp, electricity-saving lamp etc.

Kind develops

The LED light source that application semiconductor P-N junction principle of luminosity is made the earliest was come out in early 1960s.Material used is at that time GaAsP, and glow (λ p=650nm), is 20 MAHs at drive current, and luminous flux only has a ppt lumen, corresponding luminescence efficiency about 0.1 lumens/watt.

The mid-1970s, introduces element In and N, and make LED produce green glow (λ p=555nm), gold-tinted (λ p=590nm) and orange light (λ p=610nm), light efficiency also brings up to 1 lumens/watt.

To the beginning of the eighties, there is the LED light source of GaAlAs, make the light efficiency of red LED reach 10 lumens/watt.

The beginning of the nineties, glow, the GaAlInP of gold-tinted and greening, blue light the succeeding in developing of GaInN two kinds of new materials, the light efficiency of LED is greatly enhanced.In 2000, the LED that the former makes reached 100 lumens/watt at the light efficiency of red, orange district (λ p=615nm), and the LED that the latter makes can reach 50 lumens/watt at the light efficiency of green area (λ p=530nm).

The application light emitting diode of monochromatic light LED

Initial LED is used as the instruction light source of instrument and meter, and various photochromic LED was widely applied in traffic lights and large-area displays screen afterwards, created good economic benefit and social benefit.For the red traffic light of 12 inches, be adopt the long-life originally in the U.S., 140 watts of incandescent lamps of low light efficiency are as light source, and it produces the white light of 2000 lumens.After Red lightscreening plate, light loss 90%, the only ruddiness of remaining 200 lumens.And in newly-designed lamp, Lumileds company have employed 18 red LED light source, comprise circuit loss, power consumption 14 watts altogether, can produce same light efficiency.

Automobile signal light is also the key areas of LED light source application.1987, China started to install high-mount stop lamp on automobile, due to LED fast response time (nanosecond), the driver of pursuit-type vehicle can be allowed early to know travel conditions, reduced the generation of rear-ended car accident.

In addition, LED is at outdoor red, green, blue full color display, and the fields such as key ring formula mini flashlight are obtained for application.

Parameter introduces several aspects important in the optical parametric of LED: luminous flux, luminescence efficiency, luminous intensity, light distribution, wavelength.

Luminous intensity and light distribution

LED luminous intensity is that to characterize its luminescence in a certain direction strong and weak, because LED is mutually far short of what is expected in different space angle light intensity, thereupon we have studied the light distribution characteristic of LED.This parameter practical significance is very large, directly has influence on the minimum viewing angle of LED display.The LED large colour display screen of such as stadiums, if the LED single tube distribution range selected is very narrow, the spectators that display screen is so in larger angle will see the section picture of distortion.And traffic sign lamp also requires that people in a big way can identify.

Wavelength

For LED spectral characteristic we mainly see that whether its monochromaticity excellent, and it should be noted that whether the main color such as red, yellow, blue, green, White LED pure.Because in many situations, such as traffic lights require stricter to color relation, but some LED signal lamp Greens of China turn blue according to observations, and red is dark red, and from this phenomenon, we specialize in the spectral characteristic of LED is very necessary and highly significant.

Detect the detection of common light emitting diode

(1) detect with multimeter.Utilization has × and pointer multimeter that 10k Ω keeps off roughly can judge the quality of light emitting diode.Time normal, diode forward resistance is tens to 200k Ω, and the value of back resistance is ∝.If forward resistance value is 0 or for ∞, back resistance value is very little or be 0, then fragile.This detection method, can not see the luminous situation of luminotron substantially, because × 10k Ω gear can not provide larger forward current to LED.

If there are two block pointer multimeters (best same model) that the luminous situation of light emitting diode can be checked preferably.With a wire, wherein "+" binding post of one piece of multimeter is connected with "-" binding post of another block table.Remaining "-" pen connects the positive pole (P district) of tested luminotron, and remaining "+" pen connects the negative pole (N district) of tested luminotron.Two pieces of multimeters all put × and 10k Ω keeps off.Under normal circumstances, just can normal luminous after connecting.If it is not brightness is very low, even luminous, if two pieces of multimeters all can be allocated to × 1m Ω, if still very dark, even not luminous, then illustrate that this light emitting diode performance is bad or damage.It should be noted that to measure at the beginning and just two pieces of multimeters are placed in × 1m Ω, in order to avoid electric current is excessive, damage light emitting diode.

(2) external power supply is measured.Can compared with the optical and electrical properties of Measurement accuracy light emitting diode with the dry cell of 3V source of stable pressure or two joint series connection and multimeter (pointer-type or digital all can).For this reason can by connecting circuit shown in section 10.If record VF between 1.4 ~ 3V, and luminosity is normal, can illustrate luminous normal.If record VF=0 or VF ≈ 3V, and not luminous, illustrate that luminotron is bad.

The detection of infrarede emitting diode

Due to infrarede emitting diode, it launches the infrared light of 1 ~ 3 μm, and eye be can't see.Usual single infrarede emitting diode emissive power only has several mW, and the infrared LED luminous intensity angle distribution of different model is not identical yet.The forward voltage drop of infrared LED is generally 1.3 ~ 2.5V.The infrared light people just launched due to it can not see, so utilize the detection method of above-mentioned visible LED to judge, whether the forward and reverse electrology characteristic of its PN junction is normal, and cannot judge that its luminous situation is normally no.For this reason, preferably prepare a photosensitive device (as 2CR, 2DR type silicon photocell) and make receiver.By the situation of change of multimeter light-metering battery both end voltage.Judge whether infrared LED launches infrared light after adding suitable forward current.

Measuring principle light intensity

Standard lamp of luminous intensity, LED and be furnished with V(λ) the silicon photoelectric diode installment and debugging of optical filter on optical bench, particularly strictly adjust filament position, LED luminous site and receiving surface position.

First calibrate silicon photoelectric diode with standard lamp of luminous intensity, C=E/S

Rs=Is/Ds in formula

Ds is the distance between standard lamp and receptacle, and I s is the light intensity of standard lamp, and R s is the response of standard lamp.

In Et=C R t formula, E t is the illumination of tested LED, and R t is the response of tested LED, then the light intensity I t of LED is: I t=E t Dt

In formula, Dt is the distance of LED and receiving surface.

For LED, its light-emitting area is dome shape, and Light distribation is very special, so under different measuring distances, light intensity value can change, deviation distance inverse square law, even if secure measuring distance, but due to receptacle receptor area difference, its light intensity value also can change.Therefore, in order to improve measuring accuracy, measuring distance and receptor area size relatively should be given to fix as well.Such as, measuring distance is recommended to adopt 316mm according to GIE, and receptacle area is fixed as 10 × 10mm.Under same measuring distance, LED corner is different, and its light intensity also correspondingly changes, and therefore in order to obtain optimum value, it is good for preferably reading full-scale reading R t.

Luminous flux

Luminous flux measurement carries out on the turntable of goniophotometer, and on turntable, peace has turned LED, and this turntable is around vertical axis revolving ± 90 degree on its surface level, and LED is on the vertical plane around photometer axis rotating 360 degrees.Realized by step motor with the control of the corner on vertical plane in the horizontal plane.Turntable is arbitrarily movement on guide rail, and when measurement standard lamp, turntable should leave guide rail.

During measurement, traffic cycle is in the horizontal plane around vertical axis revolving, and step angle is 0.9 °, positive dirction 90 °, 90 ° in the other direction.LED self also in rotation, under each level angle, vertical plane carries out a signals collecting every 18 °, collects 20 data altogether, be calculated as follows total light flux after having turned 360 °.

If during large disc spins 0 ° ~ 90 °, shallow bid turns 0 ° ~ 360 °.But during large disc spins 0 ° ~ 90 °, likely LED installs uneven (asymmetric) and causes error, therefore best solution is that deep bid turns-90 ° ~ 0 ° ~ 90 °, shallow bid still turns 0 ° ~ 360 °, and the brightness value in angle equal for absolute value within the scope of deep bid 0 ° ~ 90 ° and-90 ° ~ 0 ° two is averaged is used as 0 ° of light emitting diode

Value in ~ 90 °.

The second method that LED total light flux is measured is that integration asks method.The advantage of the method is simple, but measuring accuracy is not high.The total light flux computing method of LED are as follows, first calculate the luminous flux phi s entered from integrating sphere incidence window (incidence window area A) 1 apart from upper standard lamp (light intensity value I s) in integrating sphere, Φ s=I s A/I 2

Read the photo-signal i s on receiver, then LED is placed on window, reads corresponding receiver photo-signal it, then the total light flux Φ of LED is:

In Φ t=It/Is Φ sK formula, K is colour correction factor.

Measuring method

The spectral power distribution of light emitting diode is measured, and object grasps spectral characteristic and the colourity of LED, moreover be to revise the luminosity value of the LED recorded.

When measuring LED light spectral power distributions, should note following some, one is that spectrum spoke strength ratio LED when comparing with standard spectrum irradiance due to standard lamp is much better than, in order to avoid this problem, preferably before standard lamp, add a neutral colour filter, make its spectrum spoke intensity close to LED.

The spectral width of LED is very narrow, in order to describe the spectral distribution profile of LED exactly, preferably adopts the monochromator of narrowband wavelength width to measure, wavelength interval be 1nm as well.

Be calculated as follows the spectral power distribution E t of LED.

Etλ=Esλ·Itλ/Isλ。

Claims (3)

1. the large-scale vehicle LED that can improve colour rendering shows multi-screen ganged control device colour temperature and brightness has no relations, and brightness is relevant with lumen value

Several related notion:

Luminous flux (lm)

Because the electromagnetic wave of human eye to different wave length has different sensitivity, we directly can not weigh luminous energy with the radiation power of light source or radiation flux, and must to adopt with the sensation amount of human eye to light be benchmark, and unit----luminous flux is weighed; Luminous flux symbol Φ represents, unit is lumen (lm);

Luminous intensity (cd)

Luminous flux is the total luminous energy illustrating that a certain light source is launched to surrounding volume; The luminous flux that Different Light sends is different in the distribution in space; The unit of luminous intensity is candela, and symbol is cd, and it represents the luminous flux that light source is launched in certain unit sphere degree solid angle (angle that this body surface is formed pointolite); 1 cd=1 lm/1 sr (sr: the sterad unit of solid angle).

2. the large-scale vehicle LED that can improve colour rendering show multi-screen ganged control device be represent eyes from a direction see the intensity of object emission light; Unit is candela/square metre [cd/m2], and symbol is L, and show the luminous flux of luminophor in specific direction unit solid angle unit area, it equals the luminous intensity that 1 square metre sends 1 candela on the surface;

Colour temperature (Color Temperature)

When the color of color and the black matrix radiation at a certain temperature of the light that light source sends is identical, the temperature of black matrix is just called the colour temperature of this light source, with absolute temperature K(Kelvin, and degree Kelvin=degrees Celsius+273.15) represent;

Colour rendering (Color rendering property)

In principle, artificial light should be identical with available light, makes the naked eyes of people correctly can distinguish the color of things, and certainly, this will determine according to the position of illumination and object;

The degree that light source presents for object color is called colour rendering; Usually " colour rendering index " (Ra) is called; Color relationship shown under the true colors (color and luster of himself) that colour rendering refers to things and a certain standard sources; The determination of Ra value, be define in DIN6169 standard 8 kinds of test colors compared under standard sources and tested light source, aberration is less, shows that the colour rendering of measured light color is better;

Ra value be 100 light source represent, the color that things shows under its light is consistent with under standard sources;

The large-scale vehicle LED that can improve colour rendering shows the intrinsic advantage of multi-screen ganged control device, is mainly used in following a few broad aspect:

The application LED light fixture of display screen, traffic signal display light source has that antidetonation is shock-resistant, speed of photoresponse fast, power saving and the feature such as the life-span is long, be widely used in various indoor, outdoor display screen, be divided into panchromatic, double-colored and single color display screen, the whole nation has 100 Duo Ge units in Development and Production; Traffic lights mainly use the red, green, yellow look LED of super brightness, because adopt LED signal lamp both energy-conservation, reliability is high again, so in China, traffic lights are just regenerated at progressive updating, and promotion rate is fast, market demand is very large, is a good market opportunity;

It is the most noticeable with the backlight of efficient side luminescence that the large-scale vehicle LED that can improve colour rendering shows multi-screen ganged control device, LED applies as LCD backlight, have that the life-span is long, luminescence efficiency is high, noiseless and cost performance high, be widely used in accutron, mobile phone, beeper, electronic calculator and machine for punching the card, along with portable electronic products small, LED backlight has more advantage, and therefore backlight manufacturing technology will to more slim, low-power consumption and the development of uniformity aspect; LED is mobile phone Primary Component, and a regular handset or Personal Handyphone System about need use 10 LED component, and a color screen and the mobile phone with camera function then need to use about 20 LED component; Present stage, cell phone back light source consumption was very large, and 1 year with 3,500,000,000 LED chips; The large-scale vehicle LED that can improve colour rendering shows multi-screen ganged control device, and it has lot of advantages, such as: the little LED of volume is that the wafer of a piece very little is encapsulated in inside epoxy resin substantially, so it is very little, very gently; Power consumption is low

LED power consumption is quite low, direct drive, super low-power consumption (single tube 0.03-0.06 watt), and electric light power transfer is close to 30%; In general the operating voltage of LED is 2-3.6V, and working current is 0.02-0.03A; In other words, the electric energy that it consumes is no more than 0.1W, equal illumination effect more energy-conservation than conventional light source nearly 80%.

3. long service life, someone claims LED light source to be long-life lamp; It is solid cold light source, epoxy encapsulation, there is not the shortcomings such as filament light-emitting easily burns, heat deposition, under appropriate electric current and voltage, 6 ten thousand to 10 ten thousand hours can be reached serviceable life, more than 10 times high brightness longer than the conventional light source life-span, low in calories, ED uses chemiluminescence technology, and thermal value is more much lower than ordinary luminaire.