The dynamism of science and technology is about to end in 2017. Looking back at the LED industry's development throughout the year, it has achieved gratifying breakthroughs in many technical problems. In 2017, the degree of industrial concentration has been further improved and development has entered a virtuous track. In particular, under the strong promotion of technological innovation in recent years, the gap between the key technologies of China's LED industry and the international level has further narrowed, and the scale of the industry has continued to expand. So what are the technical teams concerned about LED? In addition to UV UV LED, Micro LED, etc., what are the latest technological advances in LEDs?
Study found that adding boron can solve the problem of LED luminous efficiency
The Michigan Research Group released a new study in November and found that adding the chemical element Boron to the indium gallium nitride (INGan) material can increase the thickness of the middle layer of the LED semiconductor and solve the problem of luminous efficiency along with the injection current. Increase and decline. This study has been published in Applied Physics Letters.
A light-emitting diode semiconductor is composed of a P-type semiconductor having positive electric properties and an N-type semiconductor having electrons. A hole having positive electric properties will be combined with electrons and generated when electricity is applied. Light, the material used in the middle layer will determine the wavelength length.
When electrons and holes move to the middle layer, too many electrons are squeezed into the middle layer at the same time, which causes them to collide with each other and cannot be effectively combined with holes to reduce the luminous efficiency. This situation is also called European. Accumeration (Auger recombination).
The solution to this problem is to increase the thickness of the middle layer so that there is enough space for electrons and holes; however, it is not as easy to imagine how to increase the thickness of the middle layer.
Because LED semiconductors are crystalline, there is a fixed arrangement of atoms between them, which is also known as the lattice parameter. When crystalline materials are stacked on top of one another, their lattice parameters must be similar, and the rules of atomic arrangement can match with the material joints, otherwise the material will be deformed.
Researchers Williams and Kioupakis found through prediction models that the addition of boron to indium gallium nitride can increase the thickness of the intermediate layer to facilitate the combination of electrons and holes. The wavelength of light emitted by the BInGaN material is also very close to that of indium gallium nitride, and different colors can be adjusted.
Whether or not this research can actually be produced in the laboratory is still unknown, and how much boron is to be incorporated is also a challenge, but the findings of the Michigan team are a major contribution to the development of new types of LEDs.
LED Application in Microscopy
Based on its high brightness, high controllability and wide spectral output characteristics, LED has recently developed some professional lighting applications that are not well known to everyone.
Fluorescence microscopy is widely used in life sciences and is often used to study biological samples, including single cell to whole tissue samples. This process involves the use of a light microscope to stimulate the sample using a specific wavelength of light. Because of the Stokes (Stokes) displacement, the wavelength difference or frequency difference between the absorption spectrum and the peak of the emission spectrum in the electronic transition (fluorescence) generated by the material after being excited by light, the fluorescence wavelength of the beam re-emitted is greater than the original excitation. The wavelength of light. The replacement of traditionally used light bulbs in fluorescent microscopy with LED light sources has brought benefits in this area that goes far beyond reducing operating costs.
Role one: meet the spectral requirements
Some studies require the use of live cell imaging, others require the use of cells that have been chemically immobilized for a specific period of life. In any case, the type and design of the light source used to illuminate the sample has a great influence on the hardware required for the microscope and the quality and effectiveness of the recorded image.
One of the important reasons for the early use of LED systems is the convenience of users and experimental management. The most common light bulb, such as a 100 W high pressure mercury lamp, has a very short life of approximately 300 hours. The user usually records the time the light bulb was turned on in the notebook, because if the bulb is used for too long, it will increase the risk of explosion. However, LED products have a lifetime of tens of thousands of hours.
Bulbs need to be warmed up and cooled down, and this should be done all day. The LED light source can be turned on or off electronically when needed, that is, the light source is turned on during observation or imaging, and turned off when not in use. Although there are many selling points for replacing light bulbs with LED light sources, there are two major problems with high brightness and spectral range, and LED light sources have not been widely used at first.
The light emitted by the LED light source is not a broad spectrum but a Gaussian-like spectrum with a half peak width of about 10 nm to 40 nm. Therefore, the light source designer must use multiple LEDs to meet the researchers' spectral requirements, which brings about new optoelectronic and mechanical complexities in the light source design process. These problems do not exist for traditional light sources. It has become the standard method to capture and calibrate the Lambertian emission of the LED chip and then use the dichroic mirror to combine multiple colors. Lambert's law shows that the luminous intensity observed from the diffuse surface is proportional to the cosine of the included angle θ between the incident light and the surface normal. This complexity and loss cause most LED light sources to contain up to 6 different wavelengths of light.
A novel and patented method uses the concept of a wavelength group, ie, LED light wavelengths with similar spectra become a user-selectable channel. According to the requirements for high-speed applications, four sets of spectrally separated LEDs can be combined together. But the key point is that some of the wavelength groupings are rarely used in the same sample at the same time. Today, researchers can use LED light sources that contain 16 wavelengths. Using this method can increase the brightness, spectral range, and cost of LEDs.
For a long time, the green light region of the light bulb spectrum is the weakest. This region is called a “green gap†in solid-state lighting and is also an extremely weak region in the LED spectrum. One solution is to use a light stick that is excited by a series of bright blue LEDs. Compared with single-chip LEDs, using this method on a common fluorescence microscope increases the cost and is inconvenient to use. The latest research on the power of blue LED chips presents a simpler solution, namely placing a fluorescent agent directly on the LED and selecting only the fluorescent agent that provides the largest green spectral region. The following figure shows the red light excited by Stokes shift by the bright green LED.
Function two: imaging enhancement
The ultimate goal of microscopy is to obtain high-quality images. Because of its solid state characteristics, LEDs can be used directly as a microscope attachment without recalibration. Using Köhler Illumination (a sample illumination technology under a modern scientific optical microscope), the optics in the light source can image the LEDs onto the rear aperture of the microscope objective. This reverse working objective lens can evenly disperse light throughout the entire field of view of the sample. However, some LED systems still use light guides to reduce the weight and vibration of the microscope.
Filters with good blocking and transmission areas can improve the signal-to-noise ratio of the image. In typical excitation filters and emission filters used for imaging of DAPI (6-dimethyl-2-phenylfluorene) fluorophores, the excitation filter blocks the blue region of the mercury (Hg) spectrum. High energy light.
In contrast, LEDs used to excite DAPI produce extremely low energy in the corresponding excitation bands, including in the blue areas where the sample is imaged relatively weakly. The comparison result is that using an LED as a light source can obtain a better image signal-to-noise ratio because it reduces the background color gradation of the sample. Research by Sandrine Prost of the University of Edinburgh and colleagues showed that the use of wavelength-controllable, stand-alone LED light sources has improved signal-to-noise ratios over bulb systems and even surpasses some white wide-spectrum LED light sources.
At the same time, sample observations are also affected by the observation process because the cells are not suitable for exposure to high-intensity light. The negative effects of improper illumination include photobleaching and phototoxicity. Over time, light causes weakening of the signal, death of living cells, or abnormal behavior. Reducing the lighting time of the sample is critical to reducing these negative effects. Traditional lamp light sources control the exposure through a mechanical shutter, sometimes causing long delays, causing the sample to be unnecessarily illuminated during the camera's exposure time.
Using an automatically controlled LED light source can solve this problem. The LED's direct logic circuit (TTL) control achieves microsecond on/off times that are superior to USB communication. Many high-end cameras have a TTL signal output during exposure. This signal can be directly fed back to the LED light source, controlling the light source on/off and precisely matching the camera exposure time. Since two to three fluorophores are continuously imaged, the latest LED light source programs the wavelength sequence into the light source, and the cameras sequentially expose them in sequence. This circuit connection reduces unnecessary exposure of the sample, and the mechanically controlled shutter or computer control method does not have a real-time operating system.
Recently, an energy-efficient 340 nm LED light source has entered the market for the imaging of calcium fluorescence indicators (Fura-2). This application can capture neural network activity to study Alzheimer's disease and other similar conditions. Research by Peter Tinning and colleagues at the University of Strathclyde in the United Kingdom showed that using a strong 340nm or 380nm LED system can result in a 25% lower Fura-2 concentration in cells than standard cell preparation protocols. This study not only saves money for experimental research, but more importantly, it can reduce the cytotoxic effects that fluorescent labeling may cause to observe the more typical natural behavior of biological samples. (Content from "China Laser")
Corporate R&D progress
LG Develops World's First 100mW Germicidal Ultraviolet UVC-LED
LG Innotek has developed the world's first ultraviolet sterilizing ultraviolet (UV)-C LED with an output power of up to 100 milliwatts (mW). Industries that are likely to be developed in comparison to 2020 are expected to be completed two years ahead of schedule.
UV-C LED is a 200 to 280 nanometer (nm) UV product with a short emission wavelength, also known as Deep UV. The LED developed by LG Innotek at this time destroys bacterial DNA at a wavelength of 278 nm and chemically reacts with specific substances to act on sterilizing or hardening devices.
The UV-C LED can create a bactericidal device with a higher light output and stronger bactericidal power. However, due to problems such as heat generation, it is difficult to ensure stable quality. Japanese companies that have been leading the market have also planned to launch 100mW UV-C LEDs by 2020.
LG Innotek has broken the technical limitations by applying an optical output-maximizing epitaxial structure and vertical chip technology. Increased UV output and effective heat release ensure stable quality and viability. 100mW 1 LED can sterilize ultraviolet radiation for more than 10,000 hours.
With the development of 100mW optical output products, LG Innotek can more quickly expand the application of UV-C LEDs. It can quickly sterilize the flowing water or air. It can be used not only in home appliances such as water purifiers and air purifiers, but also in air-conditioning systems and water treatment equipment for buildings and automobiles.
Most of the original UV-C LED light output is 1 ~ 2mW level, mainly used for portable sterilizers or small appliances. This is because the UV-C output is weak and it is difficult to expand the application.
LG Innotek has discussed with many global companies the application of UV-C LEDs for many years. Since the market has been eager to introduce high-output LEDs, the demand for 100mW UV-C LEDs is expected to grow rapidly.
LG Innotek will accelerate the pace of ensuring the UV LED market dominance. In particular, we have exclusive technology in the field of UV-C, which has excellent sterilization and hardening properties, and are confident of occupying the market.
Prior to the introduction of innovative LED water sterilizer faucet LED modules and UV LED sterilizers for elevator handrails, quality competitiveness has also been recognized.
According to LG Innotek sources, “We will continue to increase the technological gap with the competing companies, continuously launch innovative products that meet customer needs, and lead the market.â€
BOE: Micro LED technology research has made progress
On November 29th, BOE A (000725) responded to questions from investors on the interactive platform. At present, the company has carried out technical research on micro LED displays (Micro LEDs) and has made some progress. Micro LED is a new generation of display technology. The structure is that the miniaturized LED array inherits the characteristics of the LED. The advantages of the Micro LED include low power consumption, high brightness, fast response and so on. However, because the technology is not yet mature, it will take some time to develop.
Samsung: CES or 150-inch Micro LED TV to be displayed next year
Apple's active deployment of the Micro LED screen has also been reported to be related to TSMC's efforts to solve the bottleneck problem. Samsung Electronics is not to fall behind, and it is said that it intends to show up at the Consumer Electronics Show in Las Vegas in January 2018. , published a Micro LED TV.
According to ZDNet South Korea reported on the 24th, Samsung's Micro LED TV, the screen will reach 150 inches, will be officially listed later in the year, targeting the home theater market.
It is very difficult to manufacture a reduced version of the LED. The LED used in the Micro LED screen has a size of less than 100 micrometers. Each LED chip can be used as a pixel. The advantage is that the power consumption is low, and there is no problem of burn-in of the OLED. If you use a plastic substrate, it will have flexibility. Smart phones require even smaller LED chips, so they have to wait for a while.
Samsung spokesman declined to comment. In 2012, Sony first showed off a 55-inch Micro LED TV and several prototypes, but it has not yet been commercialized.
According to the report of the LED research center of the State-Consulting Consulting Group, Sony has introduced the Crystal Micro LED display screen and received significant market attention. The advantages of its products include a wider angle of view, higher contrast and better picture quality, and can be applied to niche-type markets such as automobile showrooms, museums, and cinemas through seamless splicing. According to LEDinside's investigation, many traditional display screen factories and LCD factories are actively investing in the development of Mini/Micro LED displays at this stage. I believe that in the next 3 to 5 years, with the technology being bottlenecked, it will help the Mini/Micro LED display to enter the high-end niche market.
Sharp's investment in Sharp announced on May 22 that in order to speed up the development and commercialization of Micro LED panels, it will join hands with CyberNet Venture Capital (indirect ownership of Hon Hai 100%), Qunchuang, Rongchuang, etc. In October this year, the group company acquired eLux, a US start-up company that developed Micro LED panels.
According to Sharp, after completing the acquisition process, Sharp, CyberNet, Innolux and Rongchuang invested 31.82%, 45.45%, 13.64% and 9.09% of eLux respectively.
BDO Runda Develops Full Flip RGB COB Display Module
Since 2016, the small-pitch display has been the main R&D target for domestic and foreign display companies. Although COB technology has successfully led the development revolution of the new generation of high-definition LED displays, due to the limitation of the process technology, the COB light emitting angle and line are being installed. Distance, from the technical route, limits the performance of the product.
BDO Runda through the integration of its business unit resources, in the device, display the joint development of the two major business units, the successful output of the entire flip RGB packaged COB display module, a very small spacing of P0.95mm with a 180 ° The large-angle exposure shocked the experience and succeeded in surpassing the technical problems of the currently installed COB display screen.
At present, BDO Runda has mass-produced a single display module of 171*76mm, which can complete a 27.5-inch full flip RGB COB display through seamless splicing. At the same time when the pixel pitch reaches P0.95, it also provides High brightness 1200nits perfect specification. With a single-pixel size as small as 0.025mm2, the black optical ratio of the display has been substantially increased by 98%.
Mass-produced large angle small pitch full flip RGB COB high sharp display module
In the development phase of the progress of full-flip RGB COB experiments, the P0.5 ultra-dense display screen module model has been successfully completed. I believe in the near future, BDO Runda will bring endless possibilities to the display.
The original title on LED technology, what are they studying?
Stainless steel round steel belongs to a class of long wood, also belongs to a class of bar, the so-called stainless steel round steel refers to the cross section of uniform circular long wood, generally about four meters long. It can be divided into light circles and black rods. The so-called light circle, refers to the smooth surface, after the quasi-rolling treatment; And the so-called black rod, refers to the surface of the black thick, hot rolled directly.
Stainless steel round steel can be divided into hot rolling, forging and cold drawing according to the production process. Hot rolled stainless steel round steel is 5.5-250 mm in size. Among them :5.5-25 mm small stainless steel round steel mostly to straight strips in bundles supply, commonly used for reinforcing bars, bolts and various mechanical parts; Stainless steel round steel greater than 25 mm, mainly used in the manufacture of machine parts or seamless steel pipe billets.
Stainless steel round steel has broad application prospects, and is widely used in hardware kitchenware, shipbuilding, petrochemical, machinery, medicine, food, power, energy, aerospace, building decoration. Seawater equipment, chemical, dye, paper, oxalic acid, fertilizer and other production equipment; Photography, food industry, coastal facilities, ropes, CD rods, bolts, nuts.
304 Stainless Steel Round Rod,Stainless Steel Round Bar,Mirror Stainless Steel Round Bar,Astm Stainless Steel Round Bar
Shandong Xinsuju Steel Co.,Ltd. , https://www.sawlpipe.com