LED light-emitting diode use precautions!

A, the use of light-emitting diode current

(1) LED LAMP's normal operating current is 20mA, small voltage fluctuations (such as 0.1V) will cause a large swing in current (10%-15%).  

(2) overcurrent protection: too high a current will cause the LED lamp burnout and accelerated decay of brightness. In the circuit design should be paired with different current limiting resistors for series protection according to the voltage drop of the LED, to ensure that the LED

operating stability and in the best operating conditions. Resistor value calculation formula: R = (VCC - VF) / IF [VCC: supply voltage, VF: LED drive voltage, IF: downstream current]. 

(3) LED should operate under the same current conditions, generally advocate the use of LED current 15 ~ 18mA. Current is too large, the LED will shorten the life of the current is too small, can not achieve the required light intensity. It is necessary to ensure that the forward/reverse voltage can not exceed the maximum rated value and the use of stable forward current. 

Second, the brightness test and product use instructions 

(1) test VF, brightness, wavelength when the current must be set to 20mA, test VR when IR set to 10uA, test IR when VR set to 5V, and our test synchronization; 

Detection and use of LEDs, it is necessary to supply the same current to each LED, that is, the use of constant current detection, in order to ensure consistent measurement of brightness, the current should not exceed 20mA, the best use of 15 to 18mA of current.  

(2) the use of the product has been divided into light color, please use the BIN number in the order of categorization, can not be different levels of BIN number (each package label with identification) of the product mixed in the same product to prevent

occurrence of color, voltage and brightness differences. If you really want to mix BIN use, adjacent BIN number can be used together, but should try to prevent.  

Three, anti-static considerations  

(1) static electricity and surge voltage can damage the LED 

(2) all touch LED equipment and instruments, workbench are required to install ground, especially soldering iron and tin furnace must be well grounded; in the use of LED equipment should be anti-surge voltage measures. 

(3) operators must wear anti-static gloves, anti-static wrist and ensure good grounding, and the ground and the city ground potential difference does not exceed 5 V or impedance does not exceed 25 Ω. In touch with LED before the dissipative action, soldering iron or dip soldering equipment must be grounded, together with the use of ion fans to eliminate static electricity. It is strictly prohibited to touch the LED's two lead feet with bare hands. Because the LED anti-static for 100V, and people working on the bench humidity of 60%-90% when the human electrostatic will damage the crystalline layer of light-emitting diodes. If the LED crystalline layer has been electrostatic damage, will show some bad characteristics, such as increased leakage current, static Shun He voltage reduction or rise in the low current test does not light or light is not normal (dark), was damaged by static electricity LED operation after a period of time (such as 10 hours) will be abnormal light, darkening or failure (no light), serious will immediately fail.  

(4) anti-static wrist is necessary to test every day, failed to be replaced.  

Four, welding conditions

(1) welding LED can not be energized. 

(2) the use of soldering iron welding: the maximum power of 30W soldering iron, soldering iron tip of the highest temperature: 280 ℃, the longest preheating time of 60 seconds, the longest welding time shall not exceed 3 seconds; the use of dip welding, the highest temperature shall not exceed 260 degrees, the longest time shall not exceed 5 seconds. 

(3) soldering iron welding position: more than 4mm from the bottom of the gel; dip welding position: more than 3mm from the bottom of the gel. 

(4) in welding or heating, the temperature back to normal before, it is necessary to prevent the LED is subject to any vibration or external force on it, advocate the use of fixtures fixed welding.

Five, due to the design needs to bend or cut the foot when the pin forming method  

(1) in the LED bend and cut the foot, bend the foot and cut the foot position from the bottom of the colloid at least more than 2mm, otherwise the LED colloid colloid rupture and damage to the internal structure, the foot in the same place the number of folding can not exceed 3 times, the foot bend into 90 °, and then back to the original position for 1 time. 

(2) Bracket molding shall be done with a jig or by professionals. 

(3) Bracket forming should be completed before welding.  

(4) The stent forming should ensure that the pin and distance correspond to the distance of the board hole on the circuit board.  

(5) cut the foot because the foot cutting machine oscillation friction occurs very high voltage static electricity, so the machine should be reliable grounding, good anti-static work (can blow ion fan to eliminate static electricity). 

Six, LED device approach  

(1) pay attention to the placement of various types of LED leads, to prevent the wrong polarity installed. LED can not be too close to the heating element, operating conditions do not exceed its prescribed limits. 

(2) Please do not install LEDs in the case of pin deformation.  

(3) When deciding to install in the hole, calculate the size of the hole distance and the metric service on the panel and circuit board to prevent excessive pressure on the bracket. (4) When installing LEDs, it is recommended to use guide bushings for positioning.  

VII. Cleaning  

   When cleaning with chemicals is necessary to take special care, do not use organic solvents (such as acetone, tianna water, trichloroethylene) to clean or wipe the LED colloid, the formation of colloid surface damage and cause fading, abnormal luminescence or internal rupture of the colloid, leading to the LED internal gold line and chip over-connection damage. Formation of luminous abnormalities or internal rupture of the colloid, leading to the LED internal gold wire and chip over-connection damage.  

If you need to clean LED, advocate the use of ultrasonic cleaning LED, such as the temporary absence of ultrasonic cleaning machine can be temporarily wiped with ethanol, dipping, the moment at room temperature does not exceed 1 minute. 

Eight, operation and storage temperature  

(1) LED LAMPS: operating temperature -30 ℃ ~ 80 ℃ storage temperature -40 ℃ ~ 85 ℃. Under the condition of power, prevent the operation of high temperature above 80℃, such as high temperature operation must do a good job of heat dissipation protection measures. 

(2) LED DISPLAYS: Operating temperature -20℃～70℃ Storage temperature -20℃～85℃.

(3) OUT-DOOR LED LAMPS: Operating temperature -20℃～60℃ Storage temperature -20℃～70℃.