Optoelectronic Epoxy Mold Compounds

Epoxies are also great alternatives to silicones in regards to their refractive properties. They are cost effective solutions for mid power LED encapsulation that retain a >90% transmittance rate @400-1600nm while also staying clear (non yellow) after thousands of hours at 105°C. Their refractive index is pretty much similar to expensive phenyl silicones so they are more efficient and can accomodate a reduced cost per lumen as well as increased lumens per watt. An overall improvement.

Non yellowing

To stay on the non yellowing matter, the color of the bulb is very important for larger led lamps. It is important not to tell the "old" lamps from the new by their color. That\'s why our epoxies offer minimal transmission loss and minimal yellowing at demanding operating conditions.

Sensor replacement
Old school glass optical sensors are expensive to manufacture and difficult to miniaturize. Their require an intricate process with multiple steps to create lens filters and sensors for light sensing electronics. Enter clear epoxies which can be used as a low cost glass replacement that is easy to handle and miniaturise while are also able to adjust to your wavelength requirements. Be it for automotive, biometric or consumer applications, our light filter technology allows for precise wavelength cut off values with excellent initial and long term transmittance.

Transmission, absorption and reflection

Clear epoxies require the highest possible initial transmission and need to maintain this high transmission after aging. Mainly used in low power and high wavelength applications, clear molding compounds are widely popular in fields where early transmittance onset, high transmittance and no discolouration are strict requirements.

That\'s why we offer products with the earliest transmittance onset in the UV region (280 nm), the highest transmittance in visible & IR wavelengths that are also non-yellowing after continuous elevated temperature exposure. Products that are used to protects displays against degradation from humidity, dust, and UV exposure and are field-tested for use in outdoor displays

Optically clear epoxies are tailored for use on sensors and opto couplers with a revolutionary customized chemical filter technology that achieves the desired cut-off and bandpass transmission. So , if it wasn\'t "clear" enough yet, clear epoxies need, above all, to be transmissive.

Absorption has no place in the Optoelectronics category. Since it reduces light efficiency and generates heat it can only have a negative impact for any optoelectronic device, making it a value that needs to be reduced as much as possible. Imagine a (non opto graded) Black epoxy. It wont reflect or transmit any light through it. That\'s absorption for you. 

Reflectivity on the other hand is highly sought after for housing LED applications. 95% of the time this concerns White epoxy mold compounds that are surrounding the clear compounds. White compounds need to be highly reflective both initially and after ageing and assist into making ideal opto packages. 

Combining White and Clear compounds into a package

White colored epoxy mold compounds with low CTE are designed for applications requiring high brightness and reflectivity, and are ideally combined with clear optoelectronic molding compounds with similar CTE resulting in amazingly CTE matched LED packages.

Matched CTEs minimize warpage and the associated failures. 

As you can see in the following images it is very important for substrates and materials to be CTE matched. This means that the Coefficient of thermal expansion needs to be similar if not identical. This way when the adhesive/encapsulant/you name it shrinks, the substrate will shrink for the same %. And the same goes for expansion. So in practice you will have two (or more) materials that shrink and expand together and do not cause fractures or structural issues within their bond/package.

A higher CTE material will shrink more during cooling, or expand more during heating.

• This behavior causes warpage in the molded package.
• If adhesion between two materials of mismatched CTE is poor, delamination may occur.
• Even when adhesion is excellent, excessive thermal stress between materials with two different CTEs can lead to cracking or wire breakage.