Q: What is dominant wavelength? Please specify the ranges of wavelength in red, green and blue color respectively.
A:Dominant wavelength is defined as the best range of wavelength showing the most natural color recognized by human eyes. Researches indicate that fixed colors with wavelength of 620-630nm (red), 520-530nm (green) and 460-470nm (blue), in fact mixed in a particular proportion, can get the pure white. That is, in display field, people use luminous materials with above wavelength to make “compounded” white more natural. In order to get a good balance white led display, we specify the led colors with wavelength within 4nm for each color.
Q: What is the brightness, viewing angle and wavelength of the LED?
A: Luminous Intensity is equal to the amount of luminous flux emitted into a very small solid angle at a defined angular orientation from the light source. The measurement for luminous intensity is the candela. Symbol is IV.
Viewing Angle is the total cone angle in degrees encompassing the central, high luminous intensity portion of the LED beam from the on-axis peak to the off-axis point where the LED intensity is 50% of the on-axis intensity. This off-axis point is known as theta one-half (θ 1/2). Two times θ1/2 is the LEDs’ full viewing angle; however, light is visible beyond theθ1/2 point.
Wavelength is the distance between two points of corresponding phase and is equal to waveform velocity divided by frequency. It defines what color human eyes could recognize.
Q: For new Customers, what’s LED Display or LED screen?
A: LED Display is a video display which uses light-emitting diodes. An LED panel is a small display, or a component of a larger display or screen. They are typically used outdoors in store signs and billboards, and in recent years have also become commonly used in destination signs on public transport vehicles. LED panels are sometimes used as form of lighting, for the purpose of general illumination, task lighting, or even stage lighting rather than display.
Types of LED Display
There are two types of LED panels: conventional (using discrete LEDs) and surface-mounted device (SMD) panels. Most outdoor screens and some indoor screens are built around discrete LEDs, also known as individually mounted LEDs. A cluster of red, green, and blue diodes is driven together to form a full-color pixel, usually square in shape. These pixels are spaced evenly apart and are measured from center to center for absolute pixel resolution. The largest LED display in the world is over 1,500 foot (457.2 m) long and is located in Las Vegas, Nevada covering the Fremont Street Experience. The largest LED television in the world, the Center Hung Video Display at Cowboys Stadium, is 160 by 72 feet (49 by 22 m), 11,520-square-foot (1,070 m2).
Most indoor screens on the market are built using SMD technology—a trend that is now extending to the outdoor market. An SMD pixel consists of red, green, and blue diodes mounted on a chipset, which is then mounted on the driver PC board. The individual diodes are smaller than a pinhead and are set very close together. The difference is that the maximum viewing distance is reduced by 25% from the discrete diode screen with the same resolution.
Indoor use generally requires a screen that is based on SMD technology and has a minimum brightness of 600 candelas per square meter (cd/m², sometimes informally called nits). This will usually be more than sufficient for corporate and retail applications, but under high ambient-brightness conditions, higher brightness may be required for visibility. Fashion and auto shows are two examples of high-brightness stage lighting that may require higher LED brightness. Conversely, when a screen may appear in a shot on a television studio set, the requirement will often be for lower brightness levels with lower color temperatures (common displays have a white point of 6500 to 9000 K, which is much bluer than the common lighting on a television production set).
For outdoor use, at least 6,000 cd/m² is required for most situations, whereas higher-brightness types of up to 7,000 cd/m² cope even better with direct sunlight on the screen. (The brightness of LED panels can be reduced from the designed maximum, if required.)
Q: Which chip vendors are you buying from?
A: It depends on the Customer’s requirement. We can purchase from Japan, Korea, Europe, and USA. We are using chips mainly from Taiwan. Most take Brand of Chip packaged company such as Nationstar, KNLight Company, Kinglight Company, Anplight Company, Cotco Cree or Nicha etc