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2016August

How to test the LED luminous intensity | LED lamp

From: www.szbako.com Data:02/08/2016

How to test the

LED luminous intensity | LED lamp brightness is LED

luminescence is another important parameter, with strong directivity. Brightness refers to in a certain direction light emitting body surface brightness is equal to the light emitting surface unit projected area per unit solid angle in the radiation flux. If the surface of the light source is an ideal diffuse reflection surface, the brightness Lo is independent of the direction. The clear blue sky and fluorescent light is about 7000cd/square meters, from the ground to see the sun's surface brightness is about 14 108cd/m2.LED x brightness and the external current density, usually Jo LED (current density) increased, L. Also approximate increase. In addition, the brightness is also related to the environmental temperature and environmental temperature. (composite efficiency) decreased, Lo decreased. When the ambient temperature change. The current increases to cause the PN junction temperature, temperature rise, brightness in the saturated state. (6) the life expectancy of LED is very long, and the current density Jo is less than lA/cm, the life can be 1000000h, it can continuously light for more than one hundred years. This is the current source of any light can not compete with it. The brightness of the LED is declining as the working time is prolonged. The speed of aging is related to the current density Jo and the aging time constant R. LED luminescence intensity with long time work and the intensity of light or light intensity attenuation is called aging. The time experienced by the LED is called life. Just when the light was measured by L0, the 103-104H was measured after L1 (1000-10000h LED). For a long time, the life of LED is 106h, which refers to a single LED in 1, =20mA. With the development and application of power type LED. Foreign scholars believe that the percentage of LED's light attenuation as a basis for its lifetime. As for the original 35%. LED decay lifetime of > 6000h.
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