LED as an epoch-making source of new sources, with many traditional light sources can not compare the advantages, but also for the lighting era has brought infinite possibilities. With the rapid development of LED technology, LED has been applied to new fields.
US-developed single-chip integrated tri-color LED future will contain more color combinations
Based on gallium nitride technology and existing manufacturing facilities, strain engineering can provide a feasible method for micro-display.
Based on the strain engineering of indium gallium nitride (InGaN) Multiple quantum wells, the University of Michigan has developed a monolithic integrated amber-green-blue LED. The strain engineering is achieved by etching different diameters of nano-columns.
The researchers hope to produce a red-green-blue led in the future with a 635nm luminous quantum well, providing a viable method for a micro-display based on this pixel led. Other potential applications include illumination, biosensors and optical genetics.
In addition to support from the National Science Foundation (NSF), Samsung supports manufacturing and equipment design. Researchers hope to develop a chip-level multicolor LED platform based on existing manufacturing infrastructure.
First successful development of ultra-pure green led by researchers
Researchers at the Chemical Engineering Laboratory of the Federal Institute of Technology in Zurich recently invented a thin, curved light-emitting diode (LED) that emits a very pure green light that the researchers used to show three-letter "ETH". Professor Chih-jenshih, head of the research team, was very pleased with his breakthrough: "So far, no one has succeeded in producing pure green light like ours." ”
Prof Shih says the study will help the next generation of ultra-high-resolution displays for TVs and smartphones. The electronic device screen must be able to produce ultra pure red, blue, and green light so that the display can produce clearer, richer details and a finer range of colors to adjust the image. Prior to the technical research has been able to achieve the purity of red and blue production, but the pure color green light seems to have encountered a technical bottleneck, it is difficult to achieve technological breakthroughs, mainly due to visual constraints. Compared to red and blue light, it is difficult for the naked eye to distinguish the changes in green tones, which makes the super pure green in the technical production becomes very complex.
Prof Shih also points out that they have developed a thin, flexible light-emitting diode that can be used to emit pure green light at room temperature. "Because our LED technology does not require high temperatures, it opens up opportunities for the simple, low-cost industrial production of future Ultra pure Green light-emitting diodes," he said. "The team used perovskite crystals as LED radiation light, and the thickness of the perovskite material in the LED was less than 4.8 nm," he said. And the LED material can be made like paper can be bent, so that it can be achieved in volume to the volume of rapid production process, not only improve production efficiency, but also reduce production costs. But this ultra pure green LED will take some time before it is put into industrial use.
Led brings great changes to the optical microscope industry
In the microscope, the light source that has been applied is quartz-halogen incandescent lamp, the LED is now entering the microscope, because the halogen source usually wants dissipation 50w-100w. However, it can be seen that the halogen source is still very advantageous, they are essentially blackbody radiator.
This means that they produce continuous spectra, without any raised areas, so that any visible color can be seen and any visible color can be separated by optical filters.
"The advantage of halogen is that it is a good broad spectrum light source," said Clivebeech, a component manager at Plessey, a British led manufacturer. The spectrum is very uniform and the color is very good. ”
The first problem with halogen is the effect of protecting the sample from being heated. Beech said: "It has a high load of infra-red, which is harmful to any tissue sample or organic material, so you have to filter it out." ”
The LED avoids this layer of filtering because the standard blue core plus phosphor technology does not produce IR. "Most [LED companies] can simulate blackbody emission spectra," said Plessey optics designer Samirmezouari. But the challenge is to get the best possible performance. ”
Lighting New Achievements! New carbon nanotubes yarn can be stretched to light the LED.
In short, you take a yarn and stretch it, and it generates electricity. Sew them into a jacket without the need for a power supply, and a person's normal breathing can produce electrical signals. the University of Texas at Dallas, said in an interview recently published in the journal Science.
The yarn, called Twistron, is spun by many carbon nanotubes, with a single carbon nanotube diameter 10,000 times times smaller than the diameter of a human hair. In order to make the yarns highly elastic, the researchers continuously improve the twist to form a similar spring structure.
"These yarns are essentially a super capacitor, but they don't need to be recharged with a power supply." "said Dr. Li Na of the Nano Institute. Because the carbon nanotubes are different from the chemical potential of the electrolyte, a portion of the charge is embedded when the yarn is immersed in the electrolyte. When the yarn is stretched, the volume is reduced, the charge is close to each other, and the voltage generated by the charge increases, thus obtaining electricity.
"When stretched at 30 times per second, the yarn can produce a peak power of 250 watts/kg." A yarn that weighs less than a fly, and each time it is stretched, it can light an LED. ", one of the authors of the Institute of Nanotechnology, said," compared with other non-woven power fibers, the unit weight of the Twistron yarn produced by the power can be increased by more than a hundredfold.
At present, the most suitable application of carbon nanotube yarns is to provide power to the sensor or the IoT communication. "Based on our average output power, only 31 mg of yarn can be connected to the IoT within a radius of 100 meters, transmitting 2000-byte packets every 10 seconds." ”