1. lighting using discrete LEDs

LED lighting utilises small light emitting diodes known as LEDs. These small points of light can be used alone or together to illuminate specific areas. LEDs are thin and stable, inexpensive and last a long time. They can be used to illuminate an area in different colours and different brightness levels can be selected.

Advantages of discrete LEDs

• Thin and robust construction
• No impact on the tactile feel of buttons or snap domes
• Long operating life
• Ability to illuminate the same area with different colors
• Varying brightness level and color options
• Cost-effective

Challenges with discrete LEDs

• Potential hotspots and/or stray light
• Difficulty illuminating large areas uniformly

2. lighting light guide film

When lighting with light guide films, a thin film is used to distribute the light from one or more LEDs in a targeted manner. This technology is particularly effective for the uniform illumination of small to large surfaces, even if they are curved. It is often used in designs where thinness, compactness and flexibility are important.

Advantages of light guide films

• Limited impact on the tactile feel of buttons
• Energy efficient
• Ideal for the uniform lighting of small, large, and curved surfaces
• Suited for thin, compact, and flexible designs

Challenges with light guide foils

• Light leaks from the edges
• Potential hotspots around the LEDs
• Backlighting of the same area with several colours is only possible to a limited extent. Please ask us about the possibilities.

3. lighting using electroluminescent (EL) films

Electroluminescent (EL) films are a special type of lighting that produce a soft, uniform light. These films are made of luminescent materials that emit light when energised. At the heart of this technology are luminescent pigments, usually made of zinc sulphide, which glow when current flows.

EL films have several advantages: they are thin, flexible and can glow in different colours. They produce a soft light without harsh shadows or glare, which makes them ideal for places where homogeneous lighting is important. This type of lighting is also energy efficient and environmentally friendly as it operates at lower temperatures and consumes less energy than conventional light sources.

Advantages of EL films

• Ability to illuminate large surfaces
• Little to no effect on the tactile function of buttons or domes
• Clear light structure
• Various colour options through overprinting

Challenges with EL films

• Half-life of 4,000 hours

• Requires a DC-AC converter

• Cost-intensive than the other two options

Illumination with disappearing effect

To make a membrane keypad or glass front look good even without lighting, you can print a special "disappearing effect" (dead front) in the area of the small lights (status LEDs). When the lighting is off, this print is barely visible so that the keyboard looks uniform. As soon as the lighting is switched on, the print effect becomes visible and the LED lights appear. This effect is useful for making the keyboard visually appealing both when lit and unlit.

Advantages

• Can be illuminated selectively or across the entire surface
• Makes inactive input elements appear invisible
• Provides a better overview and user-friendliness