Analysis of high power LED in LED lighting applications

1, LED color difference problem

There is basically no chromatic aberration problem in a single LED application, but if many LEDs are put into use together or one lamp has multiple LEDs at the same time, the chromatic aberration problem will appear. Let me first talk about a group of lamps. If we can see at a glance that the colors of the lights are inconsistent, although the LEDs are divided into eight military regions according to the color temperature, like LUXEON, then several cells are divided into right in each military region, and a large range of color difference is performed to a certain extent. Control, but there are still differences in the same batch of LEDs in the same color zone, and this difference still cannot escape the provocation of the naked eye.

2, LED insulation problem

(Insulation refers to the heat-dissipating substrate for the positive and negative electrodes of the LED) We dare not say that we are the first to find the insulation problem of LED, but at least the big-name manufacturers are surprised by our doubts. Up to now, the fundamental problem has not been solved, but only to take remedial measures, such as the use of aluminum substrates to deal with insulation (the original aluminum substrate is not insulated, almost now done) may be incomprehensible. A single LED is not insulated, and the effect is small. There are problems when multiple series are connected.

3, LED anti-pulse problem

This problem is still controversial with the manufacturer. It does exist in my practical application. The main reaction is on the cold pulse, that is, at the moment of power-on, a few LEDs are broken or broken at the moment of cold power-on. I don't think it's caused by static electricity or high voltage (the starting voltage is in range).

4, the problem of LED illumination angle

Since the LED lens packages of different manufacturers are different, even if they are the same illumination angle (nominal angle), the effect is not the same, making the selection of the concentrator difficult and difficult to use.

5, LED potential blinding hidden dangers

The LED light-emitting point is too concentrated to make the center point super bright, which is easy to hurt people's eyes. Although some lighting manufacturers are making efforts in this regard, due to the lag of regulations, it can only be a moral issue for people.

6, LED fever problem

In theory, LEDs don't heat up very much, but due to the immature technology, LED heating is well known.

7, LED efficiency is low (luminosity)

At present, the LED's electrical conversion efficiency is too low (due to the lack of instrument testing, dare not give specific data).

8, LED brightness is insufficient

Insufficient brightness makes LEDs only play a supporting role in the lighting industry, mainly for decoration.

9, LED light decay and life

At present, the LED light decay and lifespan problems produced by mainland or Taiwanese companies are more serious. First, the big-name manufacturers such as LUXEON have a nominal 100,000 hours. I am afraid that they are only psychologically clear, and the heat dissipation is good or bad. Matching can affect the light decay and life of the LED, so 100,000 hours is just a selling point!

10, LED drive power problem

At present, most of the drive lines are borrowed from the switching power supply. Of course, there are also very small numbers of lines that are specifically used for LED driving, but the effect is basically the same. Since the LEDs need to be driven by DC, constant current control is adopted, which makes the driving lines quite large. Can not be compared with the electronic transformer, and the efficiency is relatively low, reaching 80% is not bad (single can not reach). In addition, in order to pursue applicability, the manufacturer claims that a driver can take ten or so casually (one, two, ... can be). In fact, this is a misunderstanding. Although it is a constant current, the initial voltage is too high. Will kill the LED in an instant.

11, limited LED shape

Due to the characteristics of LED single-sided illumination, the shape of LED lamps is limited.

12, LED unit price is too high

An imported 1W-3W LED is about $3, and more than 10 pieces are made in China (poor quality, no intellectual property rights). A 6-LED or so lamp is sold to consumers, about 1,000 yuan. Do you want to buy a color TV or buy a lamp?