2012年7月26日星期四

street solar lights in LED lumen


Increasing LED lights brightness can be broadly divided into two types, one is to increase chip itself, the amount of light emitted; Another method is the effective use of the light generated by the chip, increasing the exposure of the light irradiation to the expected direction.
street solar lights in LED lumen
The former is trying to improve the luminous efficiency of the chip active layer, as well as to improve the chip shape to increase the external light extraction efficiency, or chip, large-scale use of high current density to increase the amount of light emitted; the latter is the use of light wave control technology, that is, the package resin to form a special optical structure, the chip produced by light irradiation to the expected direction. If the LED (street solar lights) screen brightness of less than the expected value, you can also try using the following methods to improve the brightness after use.
(1) Changing the flow through the LED current, general LED tube  (street solar lights)  to allow continuous current at 20 mA or so, in addition to the red LED saturation phenomenon, the other LED brightness is basically proportional to the current flowing through.
(2) the use of the human visual inert gray scale control pulse width modulation method to achieve, that is, cyclical changes in the optical pulse width (duty cycle), as long as this repeated cycle of light is short enough , the human eye do not feel light-emitting pixels in jitter. LED display to provide a pulse width modulation is more suitable for digital control, so in general the use of computer content, almost all of the LED control system is usually composed from three parts of the main control box, the scanning plate and the display and control device. The main control box from the computer's graphics card to obtain a screen pixel colors and brightness information, and then re-allocated to a number of block scanning plate, each scanning the board responsible for controlling the LED screen on the number of rows (columns), and each row (column) on the LED display and control signal with the serial transmitted. There are two serial transmission of control signals: one is to scan the board centralized control of each pixel grayscale scanning plate from the control box of each line of pixel brightness value decomposition (Pulse Width Modulation) then the opening of the line LED signal  (street solar lights)  pulses (light does not shine to 0) to the corresponding LED on the line with serial transmission, control whether the light. Used in this way the device is less, the serial transmission of data in a repeating cycle of light, each pixel requires 16 pulses in 16 gray, 256 gray scale needs 256 pulses, the device operating frequency limit, generally only the LED lights screen to do the 16 gray.

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