Many electronic products are now designed to offer some form of backlit illumination utilising LED’s mounted behind a silicone keypad, this could be a simple indicator to show the device is powered or it could be a complete array of illuminated legends.
The most common methods of creating backlit keypads are by negative printing or laser etching.
The first option is for use where the legends are only clearly visible when the buttons are illuminated by the LED’s, and when LED’s are not powered the legends are not easily seen.
This option requires a silicone that offers good light transmission, we would then spray the keypad in an opaque coloured ink and the legends would be formed by burning the surface of the ink using a laser etching machine to reveal the legends as the base silicone material.
The second option is for where the legends always need to be visible but when the LED’s are powered the legends are illuminated, this means the product can be used in light and dark environments. This option requires a silicone that offers good light transmission; we would then spray the keypad with a lightly coloured (often white) slightly translucent coloured ink. We then overspray with an opaque coloured ink and the legends would then be formed by burning away the surface of the opaque ink using a laser etching machine to reveal the legends as the lightly coloured translucent ink layer.
Where a simple and cost-effective solution to producing a backlit keypad is required we can use a negative print to create legends suitable for backlighting. This method requires a silicone with good light transmission, we then print the top surface with a negative image of the required legend. This results in the entire button surface being printed in 1 colour except the legend as this clear of ink revealing the translucent silicone.
This is a much cheaper option than laser etching as there would only be 1 print operation required, however because we are only printing the top surface of the button you will get illumination from the sides of the buttons as well as the legend on top.
Rubbertech have the facilities to offer both options of backlit keypads in our UK factory and also at our partner in China if required. Our UK spraying facilities and latest etching technology means often our processing costs are similar to the Far East cost but offer much improved delivery times.