Views: 12 Author: rubber-keypad.com Publish Time: 2025-05-09 Origin: Site
Conductive pill is the contact medium between the rubber keypad and PCB board. A typical silicone rubber keypad involves designing a flex key webbing around the perimeter of the button. When the key is pressed, the flex key webbing allows the center of the key to make contact with the circuit, then produces a tactile response for user.
In rubber keypads, there are typically two methods of making contact with the actual switch: dome switches or conductive pills.
The basic raw material of conductive pills are typically manufactured from a silicone.
There are four prevalent conductive materials—carbon black, gold-coated, silver-coated, and nickel particles.
· Composition
Amorphous carbon clusters (10-50μm) with sp⊃2; hybridized structures
· Conductivity
10⊃2;–10⊃3; Ω·cm
· Advantages
Cost-effective.
Stable contact resistance over 1 million cycles.
· Limitations
Susceptible to arcing in high-voltage (>12V) applications.
15-25% resistance drift under 85°C/85% RH aging tests.
· Application Example
The most common conductive way. Such as, TV remote controls, etc. Silicone rubber keypad for electronic products.
Shape | Type | Diameter | Thickness | Resistance |
round, square or customized | smooth or texture surface | 2-8mm | 0.4-0.6mm | <100ohms |
Smooth Surface Carbon Pill
Texture Surface Carbon Pill
Gold-Coated Particles(Conductive Glod Pills)
· Structure
Polymer cores (30-80μm) with 0.2-0.5μm gold plating
· Conductivity
5-20 mΩ·cm (Ohmic behavior)
· Key Metrics
Contact resistance <100mΩ maintained after 10⁶ cycles
Corrosion resistance up to 200°C (ideal for automotive ECUs)
· Trade-offs
Material cost higher than carbon
Requires pulse plating for uniform coverage
· Application
Silicone rubber keypad for auto industry, medical device
· Variants
Ag flakes (1-10μm): 1.6×10⁻⁶ Ω·cm (near-bulk sliver conductivity)
AgNW (nanowires): 80% transmittance at 10Ω/sq for transparent keypads
· Failure Modes
Sulfur-induced tarnishing reduces conductivity by 40% in 500hr H₂S tests
Migration risk under >50% strain
· Application
Ag-PDMS composites enabling stretchable input devices.
Nickel Conductive Elements
· Design: Electroless Ni-P coatings (3-8μm) on silicone cores
· Performance
Initial resistivity: 50-100 μΩ·cm
20% resistance increase after 500 thermal cycles (-40°C↔125°C)
· Cost-Benefit
Cheaper than gold pill
Limited to non-critical DC circuits <100mA
· Industrial Application
White goods control panels with IP54 sealing.
Necessary tool for conductive rubber keypad.
How to produce Conductive Rubber Keyboard?
Silicone Rubber Keypad | Self Adhesive Gaskets | Rubber Sealing Gasket | Rubber Bellows | Rubber Button | Silicone Keyboard Cover | Membrane Keyboard | Membrane Switches | Remote Control Keyboard | POS Keyboard | Keypad Legends | Conductive Keypad | Keypad Cover | Keypad Feature | Liquid Silicone Rubber | Screen Printing Keyboard | Laser Keyboard | Conductive Metal Pills | Metal Dome | Conductive Button | Carbon Pills | Conductive Printing | Epoxy Coating | PU Coating | Matte Smooth | Color Coating | Plastic Key Cover | Metal Key Cover | Fluorescent keyboard | Molded Keypad | Backlight Keypad | Translucent Keyboard