LED pioneers talk about LED: is in the "infancy period"

On the whole, LED is beginning to take over the lighting market, from special lighting to all types of lighting. For now, the entire world uses LEDs in various forms and colors.

In 1962 50 years ago, Nick Holonyak Jr. and his team at General Electric invented the Light Emitting Diode (LED). Although LED light is almost everywhere today - from bridges to headlights to keychain flashlights - LED lights that look brighter than the sun are used - but their initial development is full of uncertainty. Competing research work with each other. At the time, LED was a direct result of another pioneering technology, lasers, and in the following days, LEDs have continued to evolve and have now become the lighting source of our home, and are used to transmit our data.

The magazine design channel interviewed Helenak, who is currently a professor at the University of Illinois. He asked him about the history of LEDs and discussed the future of LEDs. The following is a summary of the contents of this interview:

Q: What is the initial market response for LED?

Holenak: When I realized that I was on the road to developing LEDs, I had already beaten the entire world in the visible laser field with my own alloys. An editor of Reader's Digest called me in February 1963 and pointed out the fact that LEDs will eventually cover the entire spectrum and become a source of white light. That was what happened at the time, but I think the time for this incident to happen is not as long as 50 years.

Q: Laser?

Holenak: At that time there was a lot of speculation that light may not be coherent, just like microwave signals; or if the light energy has a coherence, the human eye may not see it because people’s eyes have been Only incoherent light can be seen.

Although others believe that ruby ​​cannot be a light source, a scientist named Theodore Maiman proposed an idea that ruby ​​can be used as a maser, but no one Had used ruby ​​to make the laser. He eventually succeeded, and I think it should be in May 1960 when he demonstrated how a laser beam was generated. After he demonstrated the first laser, everything started to break away from the cage.

In 1962, Lincoln Laboratories of the Massachusetts Institute of Technology under Robert Rediker stated that they manufactured a diode that emits many self-illumination diodes and can use this diode to fire Infrared i-line signal. When they released a report on such diodes at a conference held in July of that year, many of us said that it is possible to make it a coherent light, such as a laser?

Q: What is the difference between this and what Maiman has done?

Holenak: In the case of Maiman's laser, it was a flash similar to that used in photography. You can release a strong white light, and then the white light is absorbed by the ruby ​​rod. Then the ruby ​​rod raises all the red chromium atoms to a higher state, and then it is released and becomes a laser beam. It is a primary process that drives the secondary process. All the light you see is a source of heat, and the heat causes the atoms to vibrate lightly, releasing some light. It is better to say that the heater is better than the illuminator.

The laser I'm talking about is the light coming in from one end and coming out from the other end. In this journey it is itself a light generator, which is a diode laser.

Q: How old is the initial LED?

Howlenak: Very small. Of course, you can make it bigger, and people have already done so. You know, in the field of semiconductor applications, semiconductors will always win and sweep away from ordinary electronic products.

Q: Did the LED at the time look like today?

Holenak: The LED you see today is on an inexpensive platform, but that's just a form. In fact, LEDs can be produced in a variety of forms, and the variety and geometry can be different.

Q: What else can we do?

Holenak: There are many things that can be done to make it more suitable. We are still looking for better ways to make crystals and carry out chemical research work so that everything is in place.

I made the first alloy at General Electric. Later I made some other semiconductor alloys and they got even better - that's the alloy you can see now, they can emit red-orange light, then yellow light. Others then switched to other forms of alloy that allowed them to emit blue light; but they encountered greater difficulties in converting blue light to green light. Moreover, no one can solve the problem of obtaining yellow light very well.

Q: But after these developments, LEDs have become the dominant light source.

HOLENAC: On the whole, LED is beginning to take over the lighting market, from special lighting to all types of lighting. For now, the entire world uses LEDs in various forms and colors.

Q: Then, will we see that the usage of LEDs continues to grow?

HOLENAC: You can only think of LEDs as a light source, but you can also use it as a laser in the fields of surgery and photosensitivity. You cannot use a light bulb to do the same thing. It's like saying, I'm going to put a pacemaker made of vacuum tubes in a patient - it can only be a joke.

You can use LED to make a series of things, whether in the field of medicine, instrumentation or automotive. Some car companies have completely achieved that all the lights on the car are light-emitting diodes, which makes it unnecessary to change the headlights, taillights or lights, because the LED lights can be used for a long time.

And this is not the end, in fact, to some extent, LED is in the "infancy." Although LED has long passed the babyhood in terms of time, my feeling is that in the future it will have to go a long way. In this case, it is still in infancy.

Q: Are you still working on this job?

Holenak: No, I and my partner have other things to do. A particle flow in the transistor was originally useless, but it has now become a light emitter, that is, a laser signal, so now we have two forms of signals that can become part of a new generation of chips.

Optical information is better than electronic information. Electrons lose their power as they move from place to place, and optical signals are much better. Optical signals can also be used to make a chip, but this is something that can take 10 years, 20 years, 30 years, or even 40 years to do.