Here are a couple of issues that could arise if you do not understand an LED Half Angle and why the distribution can change in an application:
- • Lack of uniformity
- • Lower intensity
- • Lower efficiency
- • Too many LEDs
LED Specification Sheet and LED Half Angles
LED location is determined by many variables including Refractive Index (RI) of Light Panel material, light coverage requirement, light uniformity requirement, light intensity requirement and mechanical space restraints. Early consideration of backlight panel design can help streamline the design process. By providing flexibility with regards to LED location, the lighting requirements are easier to achieve. By moving the LED location closer or further away from the optical region we can see the difference in light coverage which directly affects dark spots and “hot” spots in the viewable lighting areas and are now able to create 100% light coverage on the intended illuminated zone.
It should be noted that this may cause an undesired loss of efficiency/efficacy, but depending upon the application, tradeoffs can be discussed. If there are mechanical space restraints, and LEDs cannot be moved further away, LEDs may be rotated, or optical features can be added within the light panel itself to redistribute the light and still maintain a short LED transition zone. From this design approach you can achieve 100% light coverage as well. When LED Half Angles are accounted for early in the design process it is possible to both maximize performance and reduce tooling and piece price by adequately accounting for LED type, location and reducing quantity required.