12 problems of LED Lighting Application

12 problems in High Power LED Lighting Application

 

Human’s lighting history has experienced three times: incandescent lamp, fluorescent lamp, high intensity gas discharge lamp. LED as the fourth generation light source has follows excellent characteristic: high luminous efficiency, less power consumption, long service life, safety reliability etc.  In recent years, LED lighting became popular gradually, but there are still existing some problems in high power LED in lighting application.

1, LED Color Difference Problem

Single LED application, basically there is no color difference problem. But when put many LEDs into to a lamp or with multiple LEDs at the same time, the color difference problem will be out. Although there are machines divide LEDs into 8 divisions by color temperature, with a batch of LEDs in a same color temperature still exists differenceS, and this difference is still can’t escape the naked eye.

2, LED Insulation Problem

A single LED is not insulated, impact can be ignored. But when lots of LEDs in series, insulation will be a problem.

3, LED Pulse resistance problem

This problem is still controversial. But, do exist in practical application. It mainly happened on a cold pulse. The moment of power on, a few LEDs will be breakdown or disconnected.

4, LED Beam Angle Problem

Due to various LED lens, and even the same beam angle, effect is also different. It makes it harder to select snoot.

5, LED Hidden Danger of Blinded Problem

LED light is dot light, its concentration light souce makes center super  brightness, so it is easy to hurt people’s eyes.

6, LED Heat Dissipation Problem

In theory, the LED is low hot, but as a result of current technology, LED heat’s problem is still need to be solved.

7, LED Efficiency Problem

At present, LED electric conversion efficiency is low.

8, LED Brightness Problem

For some application, like store spot light. It’s brightness is not enought to replace the traditional light.

9, LED Lumens depreciation and Life Problem

At present, LED light failure problem is still serious. Additional cooling solution is good or bad, driver matching or not is likely to affect LED light failure and life. So, 10,0000 hours are just a selling point.

10, LED Driver Problem

LED is driven by DC. Using constant current control, makes the drive circuit quite big, and efficiency low. At the same time, the driver life span is too much short than LED’s.

11, LED Modelling Limit

Due to the nature of single side lighting, LED lamp is limited by a certain shape.

12, LED Price Problem

It is still high price for quality products.

Problems in LED Application

12 problems in High Power LED Lighting Application

LED Light Soure Compare

LED Bead Compare

 

WAHLL Lighting

LED tube’s light source usually use 2038, 3014 and 3528. what’s the different and advantage? Let’s talk about it.

A: Heat dissipation way

1, Since 3528 bead’s heat is through a wire to the negative pin, so 3528 bead’s cooling mode can be referred as “negative heat”.

2. 2835, 3014 light beads are through heat-conducting fin, conduction to the aluminum base laminates directly. This operating mode is known as “electrically neutral thermal path”, which means that heat and current is not the same wire to conduction.

B. Main reason 2835, 3014 instead of 3528

1. Because of their package structure, the heat dissipation performance is better, can work in 30mA electricity.

2, 2835, 3014′s cost is better to control.

C.3528 Features

1. 3528 bead now can reach 7-8 lm with power is 0.0625 w.

2. 3528 beads have been used time longer compare to 2835 and 3014, its production process, quality is relatively stable, brightness reach 7-8lm. But mainly is the cost relatively high.  As only 0.0625 W, at the same wattage, 3528 need more beads.

D. 2835, 3014 Features

1. The middle power and small power chip’s price already gradually narrowed.

2. The brightness of 2835 and 3014 are: 10 ~ 12 lm of single bead with 0.1 w, 30mA.

Five Production Steps of LED

Five Production Steps of LED Lighting

 

 Written by WAHLL Lighting

Since electrical lighting produced, lighting is divided into three times: filament bulb era (incandescent), gas lamp (fluorescent lamp), semiconductor light era (LED). Incandescent light bulbs, with the longest history, and LED lighting will be the future lighting mainstream. Regard on incandescent and LED, you will find that, the lighting industry production work flow, China is in the downstream of the industry. Core technology is having in Europe, United States and Japan.

 

1, LED lighting principle, it is electronic through the layers of semiconductor materials, stimulate the semiconductor materials convert electrical energy into light energy. Single semiconductor lighting ability is weak, so will a lot of single layer material stack up, this is “epitaxial slice”.
LED luminous efficiency depends on, in the same thickness how many layers can be pumped. The thinnersingle layer, the more higher luminous efficiency. Now every layer thickness is only 2-20 microns. Epitaxial wafer production is the most intractable part of the LED manufacturing process.

2, Cutting – LED core technology: It is like extracting filament from tungsten material. The difference is cutting the epitaxial wafer is a square shape.
As the special structure of epitaxial slice, to cut off light intact core, it is very difficult. Not only requires a vacuum environment, but also the professional cutting machine. At present, there are few manufacturers can make this cutting machine.

3, Put the core into LED chip: Chip of LED, like the lamp holder to the light bulb, is power supply parts. “Chip” is one of the import part to achieve ideal effect, because LED’s requirement to the current is extremely high.

4, Package LED chip into illuminant: LED package like add lamp shade to filament and holder to make a light bulb. Shape can be changed according to the requirement.The packaging technology determines the service life of the LED.

5, Lighting applications: Like using incandescent bulb. according to the requirements to assemble different LED products.

For LED lighting, the first three steps of epitaxial wafer, cutting and chip are upstream, the fourth step of encapsulation is middle stream, the application of step 5 is downstream. Want to upgrade work flow, increase LED technology,  we need more energy and time to break through.

LED Technology Relationship

8 Key Pionts of LED Lights' Price

LED Lights, products are almost the same appearance, structure and function, but price is changed 2-3 times. Users get faint head, and can’t tell the difference. What are the main factors of such a big price difference? How consumers to distinguish the quality? The follows are 8 key points on impact the LED lights price.

 

Key Pionts of LED Price Life Span

The key difference of quality is in life. Life is determined by the light failure. Light failure small, the life span long. Long life LED Lights, price will be high.

Key Pionts of LED Price LED Chip

LED illuminant is LED chip. Different chip, the price difference is big. Japan, USA’s chip is expensive. At the same time, manufacturers in Taiwan and China’s LED chip price is low.

Key Pionts of LED Price LED Chip Size

Size is depending on length. The size of bigger LED chip quality is better than a small chip. The chip size is proportional to the price.

Key Pionts of LED Price Package Resin

Standard package resin is an epoxy resin. With UV resistance and fireproofing, LED’s prices is more expensive. High quality outdoor LED lighting should be resistant to ultraviolet light and fire.

Brightness

Different brightness LED, different price. Used for LED lamps and lanterns, the LED should comply with the shock wave class I. High antistatic’s LED is long life. So the price is high. Usually antistatic greater than 700 v’s LED can be used for LED lighting.

Wave Length

Consistent LED wavelength, color is consistent. Request the same color, the price is high. No LED spectral color separation apparatus, manufacturer can not produce pure color products.

Leakage Current

LED is a one-way conductive lights. If there is a reverse current, called the leakage. If leakage current is big, service life is short, certainly, price is low.

Beam Angle

Different application, LED light beam angle is different. For special light angle, the price is higher. Such as big beam angle 360.

LED price

Is that safe uses LED lights at Home?

LED lights become more and more popular. But, is that safe use LED lights?
From a goverment research, we found that although most product is safe,this is one LED ceiling light will reach middle risk if you take out the light cover. Middle risk means it will heart your eye when you watch the light directly in a close distance.
The main reason causing harm to the eye is the blue light which is contained in LED lights. The medical professionals worried about the LED blue light can harm the eye. And some LED lights have blue light overflow problem. What’s the most harmful of blue light? Research shows that the harmful effect of a different wavelength of blue light is different. The most harmful wave is from 435nm to 440nm. This effect decreases gradually with the increase or decrease of wavelength. In general, home use LED lighting’s color temperature should not be more than 4000k, should avoid using above 5000k color temperature of LED lights. So, if using low color temperature of LED lights, is safe to the human body.
And when we are using LED lights, it is important do not move the lamp cover. Generally LED ceiling light, LED panel light, LED bubble etc., with an acrylic lampshade, can be good to prevent light damage to your eyes.
In our living life, not only the LED light having blue light, but also LED TV, LED neon lights, fluorescent lamps, LED monitor, iPad, mobile phone etc. are all background light source. Through the powerful electron flow excitation light source contains high-energy shortwave blue light, which will affect children’s eye. So, should avoid watching these home appliances for a long time.

LED Lights safe?

What is Color Rendering Index

Some thing about Color Rendering Index

 

CRI-WAHLL Lighting 

 

In our life, we often encounter a scene: an apple under different light source present different color. A person’s skin show differences with real color under different indoor lighting. Hotel and restaurant use slant red light to create a warm environment. Office and factory purpose slant blue light etc. These examples are closely related to light color rendering.

Long time ago, humans have begun comparing color. They were usually put objects together to observe under the natural light (sunlight). Although incandescent light, torch, candle, and other light sources can be used for lighting, but people are used to compare color under natural light (sunlight).

Objects under the sun, will show its true color. But when the object under a florescent lamp, HID light, LED lights, the irradiation of color will have different degrees distortion. We name light source peformance real color rendering level as color rendering index.Simple as CRI. When CRI is calculated, it can be rated on a scale from 0 – 100. And it’s unite is Ra, The best performance is 100. We call close to natural light (sunlight)’s hue, the light source has a good color rendering index(high).

According to different application field, CIE divide color rendering index into five general categories:

1A, Ra> 90 Art gallerie, museum and printing industry.
2B, Ra=80-90 Family, restaurant, advanced textile technology, and similar industry.
2, Ra=60-80 Offices, schools, outdoor street lighting.
3, Ra=40-60 heavy industry factory, outdoor road lighting.
4, Ra=20-40 outdoor road lighting and some requirement low place.

Color Rendering Index

4 Points to Choose LED Tube

LED lights as its energy saving, long life span, no flicker, no noise, soft light, wide working voltage range characteristics is becoming more and more popular. Many  LED lights on the market, how to choose and buy your satisfy products?  By the follows 4 Points to Choose LED lights.

1, Package and Brand

Rated voltage, voltage range, rated power, rated frequency print in outer packaging is necessary. Generally speaking, the high quality product with high quality logo printing. The font is clear, not easy to fall off. Brand mark is clear, not easy to erase. And with the manufacturer’s trademark and related certification marks. Low quality products’ printing quality is poor, font fuzzy, easy to erase, no manufacturer’s trademarks and related certification marks.

2, LED light’s appearance

High quality LED lights, using highly pervious light cover, frosted white, and won’t see the light source inside. Compare with many same LED tubes, the tube shape and size consistent good. Cover haven’t been cracked, loose. The seal point should not have broken trace. In the process of installation, there should be no loosening of the lamp holder.

3, Woring tempreture

LED lights under normal working enviroment, the temperature rise should be low. Otherwise, LED lights life span is short.

4, Start up function

LED lights high quality startup has two characteristics: one is 0 delay starup. Second, no flash, after turn off.
If there is a quick flashing, or very dazzling, it is low quality LED lights.

how to choose led ligth

how to choose led lights

Five Production Steps of LED

Five Production Steps of LED Lighting

LED Lights 

Since electrical lighting produced, lighting is divided into three times: filament bulb era (incandescent), gas lamp (fluorescent lamp), semiconductor light era (LED). Incandescent light bulbs, with the longest history, and LED lighting will be the future lighting mainstream. Regard on incandescent and LED, you will find that, the lighting industry production work flow, China is in the downstream of the industry. Core technology is having in Europe, United States and Japan.

 

1, LED lighting principle, it is electronic through the layers of semiconductor materials, stimulate the semiconductor materials convert electrical energy into light energy. Single semiconductor lighting ability is weak, so will a lot of single layer material stack up, this is “epitaxial slice”.
LED luminous efficiency depends on, in the same thickness how many layers can be pumped. The thinnersingle layer, the more higher luminous efficiency. Now every layer thickness is only 2-20 microns. Epitaxial wafer production is the most intractable part of the LED manufacturing process.

2, Cutting – LED core technology: It is like extracting filament from tungsten material. The difference is cutting the epitaxial wafer is a square shape.
As the special structure of epitaxial slice, to cut off light intact core, it is very difficult. Not only requires a vacuum environment, but also the professional cutting machine. At present, there are few manufacturers can make this cutting machine.

3, Put the core into LED chip: Chip of LED, like the lamp holder to the light bulb, is power supply parts. “Chip” is one of the import part to achieve ideal effect, because LED’s requirement to the current is extremely high.

4, Package LED chip into illuminant: LED package like add lamp shade to filament and holder to make a light bulb. Shape can be changed according to the requirement.The packaging technology determines the service life of the LED.

5, Lighting applications: Like using incandescent bulb. according to the requirements to assemble different LED products.

For LED lighting, the first three steps of epitaxial wafer, cutting and chip are upstream, the fourth step of encapsulation is middle stream, the application of step 5 is downstream. Want to upgrade work flow, increase LED technology,  we need more energy and time to break through.

LED Technology Relationship

How to increase the reliability of LED lighting

How to increase the reliability of LED lighting

LED Light source’s life can reach 50,000 hrs,or even reach 100,000 by theory. But, as a whole LED lighting another important factor is LED driver.

For normal LED driver, usually only work about 5,000 hours. Which make LED driver become the bad actor of LED lights.

One crucial reason impact LED driver’s life is the short life of aluminum electrolytic capacitor which is the main material of LED driver.It is because after working for a long time the LED light’s temperature is high. In this condition, the aluminum electrolytic capacitor electrolyte will be quickly dries. When it happens, working days will be greatly shortened, typically only work about 5,000 hours. However, LED light source is 50,000 hours. LED driver hinder the LED lights’ development.

 

How to increse the reliablity of LED lighting the most important factor is increase the life of LED driver.

1, Some suppliers have idea deal with this problem. They create a new LED driver without aluminum electrolytic capacitors. But without it, a new problem appears, it can’t pass many tests, such as EMI test and flicker-free test.

2, Another idea is using film capacitors, ceramic capacitor or tantalum capacitor.

1) Film capacitor reach the same capacitance of aluminum electrolytic capacitor (usually 100-220 uf), the volume will be very big, and the cost will be very high.

2) Ceramic capacitor capacity is too small, usually if you use multiple ceramic capacitors to reach such capacity. Board area and the cost are too high.

3) If tantalum capacitor reach the equivalent capacity, it is too expensive. On the other hand, the pressure is too low, cannot meet the demand.

So for any other variety of capacitance, basically volume is too roomy, or too expensive. Such as for these defects with smaller capacitor capacity, remove the ripple effect is not so good, various export products required strict certification test target can’t pass, so the high quality of the LED drive power supply is still in use aluminum electrolytic capacitor.

Some suppliers said no electrolytic capacitor of the LED drive power supply plan, but probably just remove the AC aluminum electrolytic capacitor at the input side, output constant current to the aluminum electrolytic capacitor should be difficult to remove or replace.

We have to solve this problem base on aluminum electrolytic capacitor.

No doubt that, aluminum electrolytic capacitors working time problem will certainly affect the whole LED bulb life spans. But to adopt some physical methods to alleviate this problem, such as place the aluminum electrolytic capacitor on the PCB location close to the tail of lamp. Generally speaking, the most close to the LED light source, the higher temperature. And some of the highest temperature can reach 100-200 ℃, but, with better cooling metal case, usually about 100 ℃. At the tail of lamp, usually about 70 ℃. We need to pay attention to the aluminum electrolytic capacitor close to the tail of lamp, the life will be longer. Our experiment indicated, its life can reach 10,000 hours, equivalent to 10 years time, it usually family users, ten years in LED bulb are basically acceptable. Certainly, if make the cooling system better, the life will be any longer. Nowadays, 35,000hrs can be reached with good whole light performance.

LED Driver