In addition to colorful legends, printed symbols, and mechanical properties of silicone keypads, backlighting is commonly applied in these rubber keypads to enhance usability and versatility as well as overall user experience, especially in harsh ambiances. And this article will discuss the mechanism of the backlit, backlight technology, and how backlit silicone keypads improve user experience in tough environments.
What Is Backlighting?
The Backlight Mechanism
Backlight refers to light diffraction, which is the propagation of light behind an edge, and light is deflected when traveling as a wave and hitting an object. Besides, backlighting enables emphasizing the silhouette, including the legends on the key tops of the translucent silicone rubber keypad.
Not limited to silicone keypads, graphics or icons in other HMIs (human-machine interfaces) are generally operated with a backlight effect in low-light environments by offering enough illumination for legends or selective areas.
Backlit Silicone Keypad
Underneath the keytop of silicone keypads, there is a light source, which is referred to typically as light-emitting diodes (LEDs) or light guide films (LGFs). For specific requirements and improved illumination efficiency, LEDs, mounted typically in printed circuit boards (PCBs), can be positioned at the side of keys or in the center of the key.
LGF refers to a diffuser film positioned between two LEDs, which has temperature resistance with a wide spectrum in harsh conditions. It’s a flexible option for a uniform lighting effect and adaptation to any surface. Besides, LGF and fiber optic lighting also can be applied for precision backlighting.
How does light pass through legends on a silicone keypad?
For emphasizing and backlighting the legends, the silicone keypad should be treated via a negative printing or laser etching process. Our factory utilizes a precision printing technique and light diffusion under ink layers and legends to create a backlit pattern design on the keytop of silicone keypads.
However, compared to the printed ink layer on the key tops of the rubber keypads by the negative printing process, laser etching provides a more abrasion-resistant solution. Those treated legendary areas allow light to pass through.
Types of Backlighting Divided by Technology
LED & LGF, EL, and fiber optic lighting are common backlit technologies for silicone rubber keypads and other HMIs in machines by different techniques and mechanisms.
Light-Emitting Diode (LED) & Light-guided Film (LGF)
Light-emitting diodes, commonly called LEDs, are mounted on the circuit board and allow light transmission underneath the keytop with translucent silicone material or beside a single silicone button, which is applied typically in backlit silicone rubber keypads and backlit membrane silicone keypads. Design and placement of these light sources affect the energy effectiveness and backlight performance.
Electroluminescent lighting (EL)
Electroluminescent lighting (EL) applies phosphorescent ink to convert electrical energy into uniform lighting for large surface illumination, which consumes pretty little energy for dark and low-light applications.
Fiber Optic Lighting
Fiber optic lighting utilizes LEDs and fine plastic fibers, offering higher lighting efficiency, uniform light distribution, and improved durability over EL for backlighting solutions. Fiber optic lights as well as EL typically illuminate the whole surface of user interfaces in devices and equipment, while LGD can realize many independent areas in silicone keypads. However, fiber optic lamps draw more energy than energy-efficient LEDs, which also feature a maximum illumination effect.
What are the influences of tough environments for user interfaces?
Low-Light Environment
The equipment won’t always be used in areas with good lighting conditions. In areas that are outdoors, at nighttime, or warehouses with low light, ambient lighting will be poor and limited. Thus, backlit silicone keypads are significant in these operation environments to reduce input errors and unwanted accidents.
Vibration
For some construction machines or marine devices, like a vibrating excavator or a rocking boat, you can imagine continuous vibrations and unavoidable impacts can influence the life cycle and degree of wear. In terms of unavoidable vibration, silicone keypads can resist impacts and vibration in these tough conditions with integrity of user interfaces, unlike the sensitive touchscreen. Moreover, the backlit function helps you locate prominently illuminated keys in these rubber keypads with a durable lifespan of light sources inside.
Ambient Temperature Extremes
Not every user interface with physical buttons works at room temperature; they may have to be operated at freezing or high heat temperatures. And these ambient temperature extremes may affect lighting components.
Liquid Ingress
In high humidity and wet conditions, ingress of liquid is always a concern about failure of user interfaces and damage of whole machines. And a waterproof silicone keypad embedded in equipment can effectively prevent the mentioned problems by isolating liquids.
How Backlight Enhances User Experience in Tough Conditions
For maintenance and subsequent operation for the long term, environmental categories, including visibility, efficiency, robustness, ingress protection, UV exposure, vibration, and shock, are crucial for user interface with silicone keypads and other types of physical buttons. Ensuring environmental sealing and mechanical strength is essential for the performance and integrity of keypads and internal electrical components.
Improved Visibility & Safety
Unlike conventional LED strips with glare or shadows, backlighting with LEDs or LGFs illuminates the legend area with a uniform and soft glow, which improves readability and visibility in low-light environments or during power outages. The backlight is about necessary user guidance.
Your designed symbols with a backlighting effect are identified and pressed precisely, which enhances operation efficiency without an external light source. And reliable visibility in physical buttons ensures decreased cognitive load and operation safety to eliminate hazardous errors or accidents.
Efficient Illumination
Strategic LED placement, including the center or the side of a key, offers solutions for wide-area & high-intensity backlighting by centered LED placement or improved brightness in a targeted area. In terms of uniform illumination, integration with low-power LEDs and light guides is energy efficient and ensures consistent lighting for your silicone keypads.
Additionally, backlight will increase power consumption and heat production, which is unavoidable. Our efficient illumination for silicone keypads is optimal for applications of machines with reduced power demands and battery-powered devices. At the same time, low power production is beneficial to eliminate thermal issues for circuitry and electrical components.
Enhanced Robustness
The mounted LEDs in circuits are durable in case of frequent vibrations, impacts, or shocks in tough environments. Internal light sources have low sensitivity for these mentioned conditions.
Extra protective coatings can be applied to the keytops of silicone rubber keypads against UV exposure, salt fog, and friction from repeated keystrokes, which ensure wear resistance and operation safety in tough conditions.
Compatibility and Flexibility
Backlighting elements are compatible with different shapes involving flat or curved enclosures and flexible circuits. The legends and colors of lighting can be customized in a single key according to your needs.
Backlight Application of Silicone Keypad
Healthcare
Portable electronics and medical devices, referred to as emergency equipment, diagnostic monitors, patient monitors, ventilators, surgical systems, and home-use healthcare devices, are integrated widely in user interfaces.
In hospital settings, backlit silicone buttons help healthcare workers to make decisions efficiently in emergency situations in any lighting conditions. The errors and hazards should be minimized, which can be enhanced by backlit silicone keypads with precise operation.
Construction and Aerospace
The user interfaces with silicone keypads and other physical buttons in control panels or machinery that are utilized in construction and aerospace settings and require withstanding vibrations, impacts, and temperature extremes that occur continuously.
Marine and Outdoor Environments
In marine settings and outdoor environments with wet conditions, water- and shock-resistance and salt fog protection are essential for the user interface. Backlit silicone keypads retain performance and readability with wear-resistant legends and protective coating.
Common plastic buttons or membrane user interfaces are not suitable for UV exposure and repeated friction for the long term due to yellowing and sensitivity to damage. For the requirement of resistance to UV light, our factory treats silicone keypads with PU coatings.
Access Control
Access control is typically equipped outdoors or in the entry of cleanrooms, laboratories, industrial settings, and commercial uses for a reliable security system, where there are considerations of moisture, dust, and possibly relevant hygiene commands. Waterproof and sterilizable with disinfectants, access control with a silicone keypad will be backlit once your finger is pressed on a push button.
FAQ
Can custom backlit silicone keypads with LEDs not be integrated with metal domes?
Yes. Custom metal domes with a hole in the center are available to integrate with both tactile response and backlit effect via LEDs.
What level of water resistance or IP rating can backlit silicone keypads achieve?
Via wraparound and other waterproof designs, our SKF backlit silicone keypads can reach IP65 to IP64 with reliable backlight and protection against liquid and dust.
Can I custom silicone keypads with different colors of backlight?
Yes. SKF can manufacture multi-color backlit silicone keypads by mounting LEDs or using colorized ink spraying to offer noticeable visual feedback and desired functional zones.
How do you realize impact-resistant backlit silicone keypads?
The mounted LEDs in circuit boards can eliminate the influence of impacts, and the LGF technique applies a flexible film to absorb part of the impacts and to ensure uniform lights.
In extreme industrial or outdoor environments, will the translucent legends on backlit silicone keypads get worn or blurred?
The legends on our SKF silicone keypads are laser-etched and coated with protective coatings, which feature outstanding durability against wear, chemical exposure, and heavy use.
Conclusion
Our SKF backlit silicone keypads can enhance usability, visual feedback, operation safety, and backlight with stability and high efficiency, which make them optimal for application in tough environments. In applications of medical, industrial, aerospace, marine, access control settings, and outdoor, a reliable user interface solution is offered by SKF with high-quality backlit silicone keypads.
