What color and technology is the led display screen of Huayuanxiang Group?

Different materials manufactured by Huayuanxiang Group can generate photons with different energies, thus controlling the wavelength of light emitted by LED, that is, spectrum or color. The material used for the first LED in history is gallium arsenide (Ga), and its forward PN junction voltage drop (VF, which can be understood as lighting or working voltage) is 1.424V, and the emitted light is in the infrared spectrum. Another commonly used LED material is gallium phosphide (Ga), whose forward PN junction voltage drop is 2.26 1V, and the light emitted is green. 3. Based on these two materials, the early LED industry used GaAs 1-xPx structure, which can theoretically produce LEDs with any wavelength from infrared light to green light, and the subscript x represents the percentage of phosphorus replacing arsenic. Generally, the wavelength color of LED can be determined by the voltage drop of PN junction. Typical ones are the red led of GaAs0.6P0.4, the orange led of GaAs0.35P0.65 and the yellow led of GaAs0. 14P0.86. Because gallium, arsenic and phosphorus are used in the manufacture, these LEDs are commonly known as ternary LEDs. The blue led of GaN, the green LED of GaP and the infrared LED of GaAs are called binary LEDs. At present, the latest technology is a quaternary LED made of AlGaInN quaternary materials mixed with aluminum (Al), calcium (Ca), indium (In) and nitrogen (N), which can cover all the spectral ranges of visible light and part of ultraviolet light. Luminous intensity: 4. Luminous intensity is measured by lux, lumen and candlelight. 5. 1cd (candle light) refers to the luminous intensity of a completely radiated object every sixtieth square centimeter at the freezing point temperature of platinum. (It used to refer to a whale oil candle with a diameter of 2.2 cm and a mass of 75.5 g, which burns 7.78 g per hour, with a flame height of 4.5 cm and luminous intensity along the horizontal direction) 6. 1L (lumen) refers to the luminous flux of 1 CD candle shining on a plane with a distance of 1cm and an area of 1cm. 7. 1Lux (lux) refers to the illuminance where the luminous flux of 1L is evenly distributed on the area of 1m2. 8. Active illuminators generally use candle CD with luminous intensity unit, such as incandescent lamp, LED reflecting or penetrating objects using luminous flux unit lumen L, such as LCD projector; Luminance unit Lux is generally used in photography and other fields. The three units of measurement are equivalent in value, but they need to be understood from different angles. For example, if the brightness (luminous flux) of a liquid crystal projector is 65,438+0,600 lumens, and its projection size on the total reflection screen is 60 inches (65,438+0 square meters), its illuminance is 65,438+0,600 lux, assuming that its light outlet is 65,438+0 cm away from the light source and its light outlet area is 65. However, due to the loss of light propagation, the loss of reflective or light-transmitting film and the uneven distribution of light, the brightness of a real LCD projector will be greatly reduced, and the efficiency of 50% is generally good. 9. In practical use, light intensity calculation often uses data units that are easy to map or use them in different directions. For LED display screen, which is an active luminous body, CD/ m2 is generally used as the luminous intensity unit, and the observation angle is used as an auxiliary parameter, which is equivalent to the illuminance unit lux on the screen surface. Multiply this value by the effective display area of the screen to get the luminous intensity of the whole screen at the perfect angle. Assuming that the luminous intensity of each pixel in the screen is constant in the corresponding space, this value can also be regarded as the luminous flux of the whole screen. Generally, the brightness of outdoor LED display screen must reach more than 4000 CD// m2, in order to have ideal display effect in the sun. Ordinary indoor LED, the maximum brightness is about 700~2000 CD//m2. The luminous intensity of a single LED is in the unit of CD, and it is equipped with viewing angle parameters, and the luminous intensity has nothing to do with the color of LED. The luminous intensity of a single tube ranges from several MCD to five thousand MCD. The luminous intensity given by the LED manufacturer refers to the point where the LED lights up at 20mA current, and the luminous intensity is the highest at the perfect angle and center. The shape of the top lens and the position of the LED chip from the top lens determine the LED viewing angle and light intensity distribution. Generally speaking, the larger the viewing angle of the same LED, the smaller the maximum luminous intensity, but the cumulative luminous flux on the whole solid hemisphere remains unchanged. 10. When a plurality of LEDs are closely and regularly arranged, their luminous spheres overlap each other, thus producing a relatively uniform luminous intensity distribution on the whole luminous plane. When calculating the luminous intensity of the display screen, it is necessary to multiply the maximum point luminous intensity provided by the manufacturer by 30% ~ 90% as the average luminous intensity of a single tube according to the LED viewing angle and LED emission density. 1 1. Generally, the light-emitting life of LED is very long, and the manufacturer generally marks it as 100000 hours or more. In fact, we should also pay attention to the brightness decay period of LED. For example, most UR red tubes used in automobile taillights are lit for ten to dozens of hours, and the brightness is only half of the original. The brightness decay period has a great relationship with the material technology of LED production. Generally, when economic conditions permit, quaternary led with slow brightness attenuation should be selected. Color matching and white balance: 12. White is a mixture of red, green and blue according to the brightness ratio. When the brightness of green is 69%, the brightness of red is 2 1%, and the brightness of blue is 10%, people will feel pure white after mixing colors. However, the chromaticity coordinates of LED red, green and blue can't achieve the effect of full color spectrum due to process flow and other reasons, and controlling the brightness of primary colors including deviation from primary colors to get white light is called color matching. 13. Before the color matching of full-color LED display screen, in order to achieve the best brightness and the lowest cost, LED devices with three primary colors of about 3:6: 1 should be selected as far as possible to form pixels. 14. White balance requires that the three primary colors are still pure white at the same gray adjustment value. 15. Primary color, primary color: 16. Primary color refers to the basic color that can synthesize various colors. The primary colors of colored light are red, green and blue. The following figure is a spectrum table, and the three vertices in the table are ideal primary color wavelengths. If the primary colors deviate, the area where colors can be synthesized will be reduced, and the triangle in the spectrum table will also be reduced. Visually, the color will not only be biased, but also the richness will be reduced. 17. According to different wavelength characteristics, the red, green and blue light emitted by LED can be roughly divided into purplish red, pure red, orange red, orange yellow, yellow-green, pure green, emerald green, blue-green and blue-purple. Orange, yellow-green, blue-purple are much cheaper than pure red, pure green and pure blue. Green is the most important of the three primary colors, because it occupies 69% of the brightness of white and is in the center of the horizontal color arrangement table. Therefore, when weighing the purity and price of color, Zhengzhou Bank of Communications information display screen.

The green relationship is the key consideration. Four: Review of LED display screen development for 40 years