In spite of backlit silicone keypads, your rubber keypads in electronic devices or instruments can be designed with glow-in-the-dark illumination for specific applications. And the following article will discuss additives with different luminescence durations in rubber keypad manufacturing, applications by meeting the demands, and diverse glowing options, including legends on the keytops, silicone buttons, and entire elastomer keypads.
How do phosphorescent materials realize glow-in-the-dark in silicone rubber keypads?
Phosphorescent Materials as a Type of Luminescent Materials
When we hear about luminescence, fluorescence, or phosphorescence, our brain usually heats up with something that glows. Among these, fluorescence and phosphorescence belong to luminescence, and they differ just in the timescale to happen in the mentioned situation.
Overall, when the light disappears immediately, it refers to fluorescence, whereas if the light lasts, it goes to phosphorescence. For instance, the emergency exit sign or other safety signs are phosphorescent continuously.
The applications and developments of phosphorescent materials focus on materials, natural and synthetic pigments, technologies for microscopy or spectroscopy, oxygen sensors, biolabeling, and bioimaging.
How does Phosphorescent Illumination Way achieve glow-in-the-dark?
Illumination of phosphorescent substances and keypads relies on a substance to absorb light and then emit the light at a longer wavelength with lower energy. From the aspect of molecular, phosphorescence originates from the decay of an excited state of a molecule to its ground state with the concomitant emission of luminescence.
When the molecule is in its excited state, it has a higher energy. The process, including the conversion between two different electronic states, is referred to as an “electronic transition,” and the excited state is created when one electron is promoted from an occupied molecular orbital to a high-level unoccupied orbital.
How Is LED Illumination Different from the Phosphorescent Method in Elastomer Keypads?
And illumination by LEDs (light-emitting diodes) is a typical application of electroluminescence. Further, electroluminescence refers to an electrical and optical phenomenon in which a material emits light in response to the passage of an electric current or a strong electric field.
In this phase of functioning LEDs, the exited states are generated by the recombination of electrons and holes injected from the cathode and the anode. And it undergoes radiative decay to emit light.
Then your LEDs in backlit silicone rubber keypads illuminate as well as specific silicone buttons.
How Does “Glow-In-The-Dark” Work in Rubber Keypads?
Glow-in-the-dark silicone rubber keypads, also called luminous silicone keypads or phosphorescent rubber keypads, are molded by a mixture of silicone raw materials, curing agents, fillers, and special phosphorescent pigments or phosphors.
Additives Types for Grow-In-The-Dark Effect
The color additive luminescent zinc sulfide refers to zinc sulfide containing a copper activator, which is a conventional and common luminescent powder for glow-in-the-dark effect creation. Moreover, they can be applied in paints, resins, extrusion, or compression molding with rubber materials.
Our silicone raw materials and luminescent pigments are qualified with RoHS and REACH compliance and medical grade for medical rubber keypad applications.
But it cannot reach high clarity of silicone buttons, graphics, or legends in elastomer keypads for 1~4 hours, and illumination will decrease over time.
SKF also offers an improved glow-in-the-dark effect for your rubber keypads by enhanced luminescent pigments like strontium aluminate.
How Do Phosphorescent Pigments for Luminescence in Elastomer Keypads Work?
Phosphorescent pigments, like zinc sulfide, can be activated under exposure to daylight or proper artificial light and create a yellow-green phosphorescence. That is how these luminescence additives glow.
Glow-In-The-Dark Silicone Keypad Manufacturing with Glowing Legends by Laser Etching or Screen Printing
Luminescent silicone rubber keypads do not keep the entire keypad glowing, including silicone buttons and silicone keymats. Screen printing and laser etching can be applied for realizing illumination in the dark.
Silicone-based inks with luminescent pigments are applied in screen printing for graphics printing on the rubber keypads that are not mixed with phosphorescent additives and do not have a luminescence effect.
Moreover, the laser etching process enables the glow-in-the-dark silicone rubber keypads to highlight the part of the graphics on the keytop, which decreases the mistakes of keys being pressed during operation.
What Factors Should Be Taken Into Consideration of Glow-In-Dark Silicone Keypad Sources?
Glow-In-The-Dark Pigments & Illumination Duration Selection
There are diverse glow-in-the-dark pigments in the markets, offering distinct colors and glow duration. If you require occasional glowing, traditional zinc sulfide is an option. But if you want long-lasting luminescence duration for several hours or longer, color additives with strontium aluminates are more recommended.
Environmental Resistance for Your Applications with Reliable Elastomer Keypads
Based on your applications of silicone keypads, the protection level against high humidity, moisture, mechanical impact, chemicals, or salty corrosion should be determined at the same time. SKF also offers waterproof silicone rubber keypads that enable glowing in the dark in low-light ambiances.
Colors of Legends and Luminescent Additives in Silicone Keypads
If the colors of your desired legends and luminescence additive are similar, the clarity and visbility of characteristics or symbols on the keytops won’t reach enough levels for rapid recognition. These two colors had better offer high contrast, whether in the night or daylight.
When should I choose glow-in-the-dark silicone rubber keypads?
Special Illumination Way Without LEDs or Fibers
When your rubber keypad project requires illumination but with less or no power support in electronics, glow-in-the-dark rubber keypads with luminescent pigments are optimal.
Low-Light Environments
For low-light environments or at night, quickly finding your devices or desired silicone buttons in instruments is significant. Glow-in-the-dark silicone keypads, integrated into electronics or user interfaces in machines, improve effective user experience.
Applications of Glow-In-The-Dark Silicone Rubber Keypads
Remotes and Controllers
For some common consumer electronics like remotes and controllers, glow-in-the-dark helps us to find the devices and desired buttons rapidly in low-light environments. Parts of silicone buttons, like essential buttons (power, mute, and volume), can be customized with a luminescent effect.
Outdoor Operation at Night
In spite of consumer electronics indoors, luminescent silicone rubber keypads also are applied to handheld devices, scanners, VoIP phones, two-way radios, control panels in base stations, portable testers, wireless communication devices, and field equipment. Moreover, control panels for smart home or security access also can be integrated with glow-in-the-dark rubber keypads.
Continuous backlighting or other luminescence for keypads in user interfaces or devices may result in power consumption, whereas glow-in-the-dark silicone rubber keypads remain in a luminescent state with less power waste and support your electronics and instrument operation for the long term at night.
By matching your operation experience with ergonomic design, luminescent silicone keypads offer ease of legend recognition, less power consumption, and safe operations without mistakes in harsh environments outdoors.
Medical or Industrial Settings in Low-Light Environments
In medical settings, these luminescent rubber keypads enhance operational efficiency and experience in patient bedside controllers, diagnostic devices that are required to be operated in low-light exam rooms, and monitoring instruments.
In industrial factors, functionality of glowing refers to operational experience, safety, and rapid reaction in emergency situations. Emergency shut-off silicone buttons with high actuation force deal with sudden power outages or poor-visibility ambiances.
FAQs
Is the entire glow-in-the-dark silicone keypad illuminated?
Commonly, silicone buttons of silicone keypads illuminate with lower costs and enough illumination effect, but you can also choose illumination of entire rubber keypads.
How long is the glow duration of a glow-in-the-dark elastomer keypad?
In general, it lasts for about 6 hours and can be improved by long-afterglow materials (like strontium aluminates) for 10~12 hours of illumination before fading significantly.
Will the light leak from the gap or edges of the outer bezels?
Maybe. It may result in light leakage when the entire rubber keypad can glow in the dark. But we can design silicone keypads where only the silicone buttons illuminate.
What are the colors of illumination of glow-in-the-dark rubber keypads?
Typically yellow, yellow-green, blue-green, blue, and purple.
Is it safe to operate a glow-in-the-dark rubber keypad?
Yes. It won’t release toxic substances or hurt your skin or fingers during operation. These pigments are also applied in toys for children, which do not contain any hazardous chemicals or radioactive substances.
Final Thoughts
SKF offers qualified glow-in-the-dark silicone keypads for your rubber keypad project in applications of industrial, medical, construction, outdoor devices, and remotes.
Your requirements about illumination duration, colors of glowing, integration assemblies, and wanted applications of elastomer keypads can help us to offer professional engineering solutions.
