The most economical option is the non‑tactile membrane keypad.
No direct feedback: Users do not feel a snap response, but LED indicators or display changes can compensate.
Design flexibility: Non‑tactile switches allow easy customization of keypad shapes and sizes, making them ideal for unique layouts.
Tactile Membrane Keypads
Tactile membrane switches provide a noticeable snap action for clear operator feedback.
Best performance: Conductive stainless steel snap domes deliver the most reliable tactile response.
Simplified construction: Can eliminate the need for a flexible upper circuit layer.
Backing layer: A 0.015″–0.020″ backing layer helps prevent dome inversion during assembly.
Feedback options: Because of short travel, additional feedback (visual, audible, or tactile) should be considered in the electronics design. Dome switches can be added to enhance tactile feel.
A printed circuit board (PCB) can be used as the lower circuit layer:
Provides structural support
Allows integration of surface‑mount components
Can be bonded directly to your PCB or outsourced for specialized construction
Construction & Design Considerations
Material Selection: Polyester vs. Polycarbonate
Polyester overlays: Preferred for membrane keypads due to flexibility and durability under repeated use.
Polycarbonate overlays: Suitable for decals and labels, but less ideal for membrane switch applications.
Advantages of Polyester Films
Gloss or textured hard coat finishes embedded directly into the film
UV silk‑screening for texturing and gloss areas
Enhanced aesthetics and protection
Autotex XE: Excellent UV stability, ideal for outdoor applications.
Autotex AM: Embedded antimicrobial agent, perfect for medical environments requiring hygiene and cleanliness.
Circuit Layers in Membrane Switches
Two main circuit layer types are used in membrane switch assemblies:
PET (Polyester):
Circuit laid out in silver ink
Applied via screen‑printing process
Cost‑effective and reliable
FPC (Flexible Printed Circuit):
Polyimide (Kapton) base with copper etch
Similar to PCB manufacturing but thinner
Allows soldering of components and connectors
Best suited for fine circuit pitches under 1mm (e.g., 0.50mm
Typical Membrane Switch Layer Structure
Graphic Overlay (Top Layer)
Printed polyester or polycarbonate sheet.
Provides the visible interface with icons, text, or branding.
Designed for durability, chemical resistance, and user aesthetics.
Overlay Adhesive
Bonds the graphic overlay to the spacer or circuit layer.
Must be thin and transparent to avoid distortion.
Spacer Layer
Contains cut-outs (windows) that separate the top and bottom circuits.
Ensures the switch only activates when pressed, preventing accidental contact.
Upper Circuit Layer
Flexible printed circuit (often PET film with conductive ink).
Carries the conductive traces and switch contacts.
Spacer Adhesive
Holds the circuit layers apart while allowing precise alignment.
Lower Circuit Layer
Printed circuit with conductive traces.
Completes the electrical path when pressed against the upper circuit.
Rear Adhesive / Backer Layer Bonds the membrane switch to the product housing or enclosure. Provides mechanical stability and environmental sealing.
Circuit Layers in Membrane Switches
Two main circuit layer types are used in membrane switch assemblies:
PET (Polyester):
Circuit laid out in silver ink
Applied via screen‑printing process
Cost‑effective and reliable
FPC (Flexible Printed Circuit):
Polyimide (Kapton) base with copper etch
Similar to PCB manufacturing but thinner
Allows soldering of components and connectors
Best suited for fine circuit pitches under 1mm (e.g., 0.50mm
Typical Membrane Switch Layer Structure
Graphic Overlay (Top Layer)
Printed polyester or polycarbonate sheet.
Provides the visible interface with icons, text, or branding.
Designed for durability, chemical resistance, and user aesthetics.
Overlay Adhesive
Bonds the graphic overlay to the spacer or circuit layer.
Must be thin and transparent to avoid distortion.
Spacer Layer
Contains cut-outs (windows) that separate the top and bottom circuits.
Ensures the switch only activates when pressed, preventing accidental contact.
Upper Circuit Layer
Flexible printed circuit (often PET film with conductive ink).
Carries the conductive traces and switch contacts.
Spacer Adhesive
Holds the circuit layers apart while allowing precise alignment.
Lower Circuit Layer
Printed circuit with conductive traces.
Completes the electrical path when pressed against the upper circuit.
Rear Adhesive / Backer Layer Bonds the membrane switch to the product housing or enclosure. Provides mechanical stability and environmental sealing.
Membrane Keypads: Tactile vs. Non‑Tactile Options
Tactile Membrane Keypads with Metal Dome
Tactile membrane switches use pressed stainless steel domes to provide clear tactile and audible feedback.
Characteristics:
Raw material: Pressed stainless steel
Plating options: Nickel, silver, or gold
Typical sizes: 8–20 mm
Actuation force: 200–400 grams (depending on dome type)
Total travel: 0.033–1.17 mm (varies by dome size)
Rebound duration: Depends on dome size
Lifespan: 1–5 million actuations
Switching voltage: 1–50 VDC
Switching capacity: 1 Watt
Switching current: 0.005–100 mA DC
Operating temperature: –45°C to +100°C
Storage temperature: –55°C to +100°C
Advantages
Wide range of sizes and actuation forces
Strong tactile effect with audible feedback
Long lifespan
Suitable for high‑temperature environments
Disadvantages
Requires a rigid actuation surface for proper performance
Can be damaged if the membrane keypad is bent during application
Tactile effect reduced if excessive overlay material is applied
Non‑Tactile Membrane Keypads
Non‑tactile membrane switches provide no tactile or audible feedback. Circuit closure occurs directly between the top and bottom contacts, separated by a spacer/adhesive layer.
Characteristics
Raw material: Polyester with printed conductive ink
Key size/shape: Customizable per application
Rebound duration & travel: Application‑dependent
Lifespan: 5–10 million actuations
Operating temperature: –40°C to +85°C
Storage temperature: –40°C to +85°C
Advantages
No mechanical components required
Extremely long lifespan
Cost‑effective and simple construction
Suitable for large‑surface keys of varied shapes
Disadvantages
No tactile feedback
Audible feedback must be programmed electronically
Not recommended for embossed graphic overlays
Membrane Keypad Quotation
Our preferred method for quoting is via 3D drawings (STP or IGES format).
We can also quote from 2D dimensioned drawings or sketches.
