ASA Color LED
ASA Color LEDs are available based on existing tooling to mold a compatible cap. Electrical/thermal characteristics match base Nichia LED.
A unique integrated remote phosphor assembly, the ASA Color LED is a blue diode surface mount LED with adhered silicone rubber cap.
Capped base LEDs are exclusively world-leading Nichia products.
ASA Color LED is a discrete, monochrome, low- to mid-power visible light LED+cap assembly.
It offers free customization of target color (chromaticity) as well as optical control of brightness (intensity) with optional shader.
Optimal use is in consumer-facing applications with great care for design/aesthetics, or in applications with exacting color requirements for operator ergonomics.
Example implementations are durable goods with backlit graphics/buttons or light-up indicators, such as vehicle cockpits, household appliances, or branded/high-end decorative lighting.
It is reflow solder and pick-and-place ready, suitable for all standard manufacturing techniques, and ready as a drop-in replacement.
Mass produced for 2 decades, the ASA Color LED has a track record of billions sold.
Any individual wavelength of light will resolve as a maximally saturated color on the rainbow
Less saturated colors, notably white, require photons of multiple wavelengths mixing
Any white LED is a mixture of blue (or violet) diode with some combination of green~yellow~red wavelengths.
Phosphors are chemicals that absorb light of one wavelength and re-emit at a lower energy, longer wavelength, providing the effect of turning blue light into green~yellow~red. Mixed with some of the original blue light passing through, the result is a white or other unsaturated color light.
Typical white LEDs use blue diodes with phosphors in the potting; the ASA Color LED simply moves these phosphors to a separate cap.
CIE 1931 Diagram
2D Representation of Human-Visible Color Space
The 1D visible spectrum rainbow above has been bent around the outside of the curve in increasing wavelengths (decreasing energy) from violet to red. White and other less saturated colors derived by mixing wavelengths fill the center.
Of course you are familiar with another way to create unsaturated colors: the display you are reading this on uses pixels in red, green, and blue, mixing them at various relative power to create a rich gamut.
The common sRGB gamut triangle is shown above. Color changing LEDs work this way as well, typically with three diodes in R/G/B quite similar to screen pixels.
Most screen gamuts are weak in the cyans, showing only a fraction of possible human perception.
Taking the modular approach of moving phosphors to a separate cap, while counterintuitive at first consideration, has several advantages.
Variations in blue diodes can be corrected by pre-binning and matching phosphors, allowing extremely precise targeting.
ASA Color LEDs are always available in a single, tightly-defined chromaticity rank.
For the same reason, customization comes as a matter of course. Asahi Rubber adjusts the cap to match the diodes anyhow, and adjusting the cap to move a target is no extra effort.
ASA Color LEDs support custom centerpoints for pretty much any chromaticity an sRGB display can show, plus a bit extra around the edges.
Precise targeting of any centerpoint is available–but not only that, the production run will come out as a normal distribution around that target.
Three problems are solved:
- You never have to buy a rank you don’t want
- You never have to buy more than one rank
- Corner cases taking your module out of spec are at or near zero
Intensity is also carefully controlled with the modular capping system, creating a normal distribution.
First we tightly bin blue LEDs by intensity as well as chromaticity.
Then a common denominator is set with an intensity specification, and shaders are added to darken the cap to even them out.
This provides the additional option of optical dimming–another tool to use with or instead of resistor adjustment or PWM to bring your module luminance in-spec.
Asahi Rubber Color Matching
With us as your supplier you can iterate freely and rapidly without having to renegotiate bin selection and pricing.*
The timescale for creating a new specification is a few days, making the ASA Color LED an ideal choice for dealing with last-minute changes on a project with exacting requirements.
*so long as base LED remains the same and with some rare exceptions
We can readily produce parts when provided a defined target chromaticity x and y coordinates (or u’, v’) and clarity on desired package footprint and intensity/flux.
If you have these values ready and wish to discuss procurement, or if you seek advice to help work through defining these values, please contact us and we’ll be happy to help!
Additionally, Asahi Rubber offers a color matching service to support your engineering.
Leveraging our decades of experience from back in the days of incandescent filter caps, we’ll receive your set shipped to our factory and find the precise LED specification you need to hit your set target chromaticity and luminance specs. Please contact us and we’ll be happy to help!