When a protective disc is mounted on top of a light-emitting display, such as an LCD, interference inevitably occurs reflections from the layers the outside light hits. Optical lamination involves filling the gap between the LCD and the disc with an optically clear material. This eliminates all visible light reflections in the interlayers.
While the reflections disappear, optical lamination brings a whole host of improvements: the image from the screen is perceived to be much clearer in colour and brightness, the viewing angle increases and contrasts are enhanced. These things add up to a very big difference - the laminated screen is perceived as so much more attractive and elegant that most people who see the two variants side by side for the first time start to wonder what's wrong with the non-laminated screen.
Using clear silicone to laminate has another major advantage: the product is more resistant to shock and impact, thanks to the softness and elasticity of silicone.
The image below shows how the concept works. An air gap allows light to bounce from the bottom of the glass and the top of the screen back up, which appears as annoying reflections.
If you fill the air gap with a transparent material, the reflections of the interlayer disappear, in the picture Reflection 2 and Reflection 3. What you need to add is an anti-reflection treatment on the top of the disc, which can almost completely remove the top residual reflection.
There are a few different varieties of materials to use for optical lamination, and silicone is a very common and technically sound solution. The advantages are numerous:
- High light transmission: over 95 %
- Refractive index 1.43-1.53, depending on the product
- Does not yellow over time
- Not affected by even strongly UV light
- Low surface tension provides perfect lamination and filling of micrometre-level irregularities
- Can be cured at room temperature, heat or with UV light
- Hardly any shrinkage - for robust production
- Excellent ability to absorb vibrations and impacts
- Minimal water absorption
- Maintains its mechanical properties over a very wide temperature range
In addition to its technical advantages, silicone is very friendly to the working environment as it is not classed as a thermosetting plastic. The optical lamination variants also have no odour and are generally very pleasant to work with.
Tribotec stocks and sells several different types of silicone for optical lamination. Please contact us if you want to know more!
