The leads should be formed so they are aligned exactly with the holes on the PC board. This will eliminate any stress on the LEDs.
Use LEDs with stoppers or resin spacer to accurately position the LEDs. The epoxy resin base should not be touching the PC board when mounting the LEDs. Mechanical stress to the resin may be caused by the warping of the PC board when soldering. The LEDs must not be designed into a product or system where the epoxy lens is pressed into a plastic or metal board. The lens part of the LED must not be glued onto plastic or metal. The mechanical stress to the leadframe must be minimized.<,p>
Solder the LEDs no closer than 3mm from the base of the epoxy resin.For solder dipping, it may be necessary to fix the LEDs for correct positioning. When doing this, any mechanical stress to the LEDs must be avoided.
When soldering, do not apply any mechanical force to the leadframe while heating.Repositioning after soldering must be avoided.
Avoid exposure to chemicals as they may attack the LED surface and cause discoloration. When washing is required, "isopropyl alcohol" is to be used.
The influence of ultrasonic cleaning on the LEDs differs depending on factors such as oscillator output and the way in which the LEDs are mounted. Therefore, ultrasonic cleaning should only be performed after making certain that it will not cause any damage.
LED emission wavelengths vary. LEDs are classified by emission color into different ranks. When a large volume of LEDs are purchased, LEDs with different color ranks will be delivered
The leadframes of the LEDs are coated with silver. Care must be taken to maintain a clean storage atmosphere. If the LEDs are exposed to gases such as hydrogen sulfide, it may cause discoloration of the leadframes. Moistureproof packing is used to keep moisture away from the chip type LEDs. When storing chip type LEDs, please use a sealable package with a moisture absorbent material inside.
LED Cluster Lamp and LED Dot Matrix Unit
Please refer to the recommended distance between the leads when designing lead holes on the PC board.Close attention must be paid on the correct positioning of O-rings and other water proof seals when assembling products/systems.
LEDs are vulnerable to static electricity. When handling the LEDs, necessary precautions regarding static electricity must always be taken into consideration.
Installation of LEDs
Make certain that the lead position and polarity are correct when installing the LEDs.The interface cable must be as short as possible.
The power supply and ground line must be selected according to their current capacity.
When many LEDs are mounted into a small area, heat generation must be taken into consideration. If there is a possibility that the ambient temperature may exceed 60 degrees centigrade, some kind of forced cooling system will be needed.
The ambient operating temperature must be taken into consideration when a product/ system is being designed. There are certain limits to maximum current, at certain temperatures which must be kept in mind.
When the surface of the LEDs must be cleaned, the LEDs should be wiped softly with detergent. The surface may be damaged and the effect of the lens may be reduced with violent scrubbing.
EMI countermeasures must be taken as a system.
When instantaneous power failure, or a current surge by lightning stops the controller at abnormal conditions, the abnormally high electric current may continue running through the LEDs for an extended period of time. This can damage the LEDs in the system. Circuit protection against abnormally high current must be built into the system to protect against this.
Copyright: Data Display Products 01/01/00
Disclaimer: The information provide herein are basics to educate one on the operating properties and user characteristics of LEDs. We do not imply that the information is accurate or applicable to every aspect of LED usage. Each application will have to be performed on its own merits and with full understanding that damages and injury are the sole responsibility of the "builder". We do not dispense engineering advice. You need to determine the specific products you will need for your specific application.