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- Products for optoelectronics
 
 

 

  
  Outdoor applications, such as signal lamps, information panels, motor vehicle lights, etc., are exposed to exceptional climatic influences. We have developed special products for this application field that not only protect against environmental influences but also fulfil highest functional and optical demands like very high transparency or light diffusion.

Besides various transparent and opaque casting compounds and resins we offer our unique transparent and opaque ELPEGUARD® conformal coatings. To avoid or indeed create different light effects, such as diffusion or absorption for example under LEDs, we have developed various lacquer systems for substrate coating.

For the increasingly important issue of thermal management in optoelectronics we offer thermally conductive heatsink pastes.

 
   
 
Transparent conformal coatings for optoelectronics
 
       
  Conformal coatings of the series ELPEGUARD® SL 1305 AQ-ECO
On account of its superior yellowing resistance this environmentally friendly, water-borne and fast drying conformal coating series is especially suitable for use in optoelectronics. The possibility of individual transparent colouration in red, green or blue by means of special dyestuff concentrates enhances its versatility.

Conformal coatings of the series ELPEGUARD® SL 1307 FLZ/2
 Fast drying, excellent protection, extremely high yellowing resistance and easy to repair – these properties characterise our conformal coatings of the series ELPEGUARD® SL 1307 FLZ/2.
Filled in handy aerosol cans, conformal coating ELPEGUARD® SL 1307 FLZ-S is always at your fingertips for service and repair work as well as for the quick coating of pilot and low-volume series'.

ELPEGUARD® thick film lacquers of the series TWIN-CURE® DSL 1600 E-FLZ and diffuser ink EH 13.400 UV
 The TWIN-CURE® thick film lacquers are UV-curing, solvent-free systems that exhibit high transparency and yellowing resistance. They are excellently suitable for coating optical components, such as sensors or LEDs. On account of a second curing mechanism the lacquers cure completely even in shadow areas without an additional tempering step.
With the diffuser ink EH 13.400 UV, a matt-finish UV-curing lacquer system which effects a diffuse light dispersion, the scattering angle of LEDs can be increased.
EH 13.400 UV is applied as an additional layer over the thick film lacquers of the series TWIN-CURE® as it has a purely visual effect and is not electrically insulating.

Silicone thick film lacquers DSL 1705 FLZ and DSL 1706 FLZ
 These solvent-free, colourless transparent 1-pack thick-flim lacquers, based on polyorganosiloxane, convince also at high temperatures up to 180 °C and high moisture stress by their resistance against weathering influences and UV radiation as well as their high chemical resistance.
DSL 1705 FLZ is an addition crosslinking, thermal curing conformal coating for the application of thick films up to 3 mm.
The three viscosity adjustments of DSL 1706 FLZ are room temperature condensation crosslinking conformal coatings for the application of thick films up to 300 µm.

 

 

  
   
 
Opaque conformal coatings for optoelectronics
 
       
  ELPEGUARD® conformal coatings SL 1347 and SL 1397

 Selective coating with the white opaque conformal coating ELPEGUARDâ SL 1397 ensures maximum luminous efficacy: The LEDs are left uncoated while dark components are hidden, thus amplifying the luminous efficacy (reflectivity) considerably. As key characteristics, ELPEGUARDâ SL 1397 boasts very high reflectivity ratings (> 0.9 at 460 nm) along with high UV and thermal stability.

Application of the black opaque, mat conformal coating ELPEGUARDâ SL 1347 ensures a strong contrast to the base material. With this material, it is possible to coat selected areas of assemblies (which are usually coated with green solder resist) in black to achieve a strong contrast of the LEDs to the non-reflective base material. This is of particular advantage in applications with emphasis on high optical quality, such as information panels, traffic lights, etc.

 


 

  
   
 
Casting compounds for optoelectronics
 
       
  Crystal clear Wepuran casting resins of the series VT 3402 KK
The solvent-free Wepuran casting resins of the series VT 3402 KK, based on polyurethane resin, are absolutely colourless and crystal clear. Their extremely high transparency means they can be used for applications with highest demands on optical properties. Due to their excellent climatic resistance and exceptional UV light resistance they are also suitable for use out of doors.
Moreover, the Wepuran casting resin VT 3402 KK-NV-UVP protects the potted substrate against weathering influences caused by UV radiation. This effectively prevents the substrate from chalking and thus increases the reliability of the use of LEDs in an outdoor environment.
Also, by adding the hazing paste TP 3492 LS to the casting resins of the series VT 3402 KK a light dispersing effect can be created. Furthermore, by adding one of the dyestuff concentrates FK 3432, red, FK 3452, blue, FK 3462 YG, yellow-green, or FK 3462 DG-P, dark-green, a specific colouring can be achieved.

Weather resistant Wepuran casting resin VT 3404 HE
The Wepuran casting resin VT 3404 HE is based on polyurethane resin and exhibits a good weathering resistance especially for applications which place no particular demand on the optical properties, e.g. for encapsulating assemblies where an opaque potting result does not restrict their use. Due to the highly elastic adjustment (Index H, Shore A = 50) the casting resin can be easily removed for repair purposes.

Economic highly transparent Wepuran casting resin VT 3405
The Wepuran casting resin VT 3405 is clear and highly transparent and based on polyurethane resin. It is distinguished by a good weather/UV light stability and moderate optical thermal stability and therefore is particularly suitable, for example, for potting assemblies which must remain permanently visible. With a Shore A hardness of just 35 this casting resin is highly elastic and can be easily removed for repair purposes.

Clear transparent Wepesil casting resin VT 3601 E
 This casting resin, based on silicone rubber, is also colourless and clear transparent as well as weathering and UV resistant. Furthermore, it is characterised by its excellent temperature resistance up to 200 °C as well as by its extremely high elasticity and tear resistance.

Black Wepuran casting compounds VU 4442/61 HE, VU 4443/61 HE and VU 4444/31 SB-WB
 These solvent-free casting compounds are used to seal or pot electrical components and assemblies. The compounds are absolutely opaque and jet-black in colour, thus exhibiting an excellent contrast to LEDs embedded with these compounds.
VU 4442/61 HE and VU 4443/61 HE are slightly less viscous and thus are particularly suitable for component geometries that are difficult to access.VU 4442/61 HE exhibits a high temperature resistance of 120 °C, whereas the other two casting compounds are utilisable up to 90 °C. VU 4444/31 SB-WB is hardly flammable and exceptionally weatherproof.

White Wepuran casting compound VU 4490/31 K
 Due to its high yellowing resistance this white casting compound based on polyurethane resin is especially suitable for use in optoelectronics. Even when exposed to intense sunlight only minimum yellowing of the surface is to be expected which, however, does not have any influence on the protective effect. High-quality and shock-sensitive electronic components, LED lamps, illuminated keyboards and fittings, etc. are reliably protected by the comparatively hard potting. The smooth white surface gives the potted object a particularly elegant appearance.


 

 

 

 

  
 

   
   
 
Heatsink pastes for optoelectronics
 
       
  1-pack heatsink pastes HSP 2740 and HSP 2741 for the thermal management of LEDs – for a longer life cycle

The life cycle of LEDs essentially depends on the operating and ambient temperature. Indeed, compared to light bulbs, total breakdowns rarely occur, but rather a decrease in the illuminating power takes place, which however can be accelerated by heat accumulation during use. To guarantee a consistently high radiation performance, the pcb or additional heatsinks must disperse the heat reliably.

In many cases this can be achieved by means of our heatsink pastes HSP 2740 and HSP 2741. They are screen and stencil printable pastes with a high thermal conductivity and excellent electrical insulation properties.

Compared to the conventional processes the number and size of the heat transition resistances can be greatly reduced by using a heatsink paste. Moreover, on account of their screen printability these systems are very economical to apply.

 
   
 
Lacquers for substrate coating
 
       
  A white LED assembled on a standard green solder mask may "reflect" a pale green light. This falsification of the colour spectrum can be effectively avoided by a neutral white or black substrate coating.

White solder resists and marking inks
 Ultra-colour stable lacquers are especially suitable as a reflective background for LED applications, such as the white photoimageable ELPEMER® solder resist SD 2491 SM-TSW-R2 or the 2-pack solder resist SD 2496 TSW, or the corresponding marking inks ELPEMER® SD 2691 TSW and SD 2696 TSW which keep their pure white colouration even after reflow soldering and temper processes. Underneath white LEDs they totally prevent the substrate from influencing the light colour. If LEDs are assembled on flexible substrates a special flexible lacquer system, such as the white UV curing solder resist SD 2490/201 UV-FLEX-HF, should be used.

Black solder resists and marking inks
 If all kinds of reflection should be avoided, the application of a black solder resist, as for example the photoimageable solder resists ELPEMER® SD 2447 SG (silk-glossy), SD 2447 SM (silk-mat) and SD 2447 XM (extra mat), or the mat conventional 2-pack solder resist SD 2444 NB-M, or the black marking ink SD 2642 T, is recommendable. On flexible substrates the black UV curing solder mask SD 2440/201 UV-FLEX-HF can be applied. Especially lacquers with a mat surface behave favourably with regard to light reflection.


 

  

Upon request we will gladly provide you with further information as well as  free of charge samples of our special products for optoelectronics.

  Lackwerke Peters GmbH + Co KG, Hooghe Weg 13, 47906 Kempen, Tel.: +49 (0) 2152-2009-0, Fax.: -70, peters@peters.de, www.peters.de, Impressum