Contact element for keypads

Part of the Shin-Etsu range of keypads is the contact element at the bottom section of each key that makes the actual electrical contact on the PCB or FPC. A range of materials are offered to meet various specific requirements towards switching electronic equipment. In addition to passive contact elements, metals domes are available that include a specific metal click-response.
Attaching metal domes to the keypad has the advantage that the pressure point is always centralized on the dome guaranteeing best click feeling by eliminating certain assembly tolerances.

Keypad contact element types

Type	Conductive material		Hardness	Tensile strength	Elongation	Compression set	Resistivity	Contact resistance	Size ∅	T
Unit			Shore A	N/mm2	%	%	Ω.cm	Ω	mm	mm
DCP	Direct Contact Print carbon silicone ink layer		(50)	(9)	(350)	(10)	4.0	< 200 20 typical	Various shapes 2.5 ~ 6.0	> 0.03
C40P	Carbon silicone rubber pill		65	5	200	18	4.0	< 200 20 typical	Round 2.5 ~ 5.0	0.55
Alpha97	Carbon silicone rubber pill		80	6.7	160	36	0.7	< 20 5 typical	Round 3.0, 3.5, 4.0	0.55
Gold	Au plated Ni/Cu plate		(50)	(9)	(350)	(10)	1.0 . 10^-2	< 2 0.5 typical	Round 3.0, 3.5, 4.0	0.5
H-flex	Au plated Ni/Cu plate		(50)	(9)	(350)	(10)	1.0 . 10^-2	< 2 0.5 typical	Round 3.0	0.55
			JIS K6301A	JIS K6301	JIS K6301	JIS C2123 150 °C, 22hrs
Test based on Shin-Etsu standard test on Au plated PCB, 1.0 pitch, track width 0.5 mm.

Keypad metal domes contact element types

Type	Conductive material		Size ∅	Contact resistance	Peak force	Stroke	Click ratio
Unit			mm	Ω	N	mm	%
MD	SUS			< 50	0.8 ~ 8	0.8 ~ 1.5	0 ~ 70
IF	SUS301CSP-H		4.0	< 50	1.8 ± 0.4	0.14 ± 0.05	45 ± 10
IF	SUS301CSP-H		5.0	< 50	1.8 ± 0.4	0.18 ± 0.05	45 ± 10
IF	SUS301CSP-EH		5.5	< 50	3.8 ± 0.5	0.23 ± 0.05	40 ± 10
IF	SUS301CSP-EH + carbon coating		5.5	< 100	3.9 ± 0.5	0.24 ± 0.05	40 +10/-15