Ultra-low Profile Dome Key
B3D
Single-key Type Added to Series of
B3DA Ultra-low Profile Dome Arrays
■ No soldering required. Attach directly to PCB to
make an ultra-low profile tactile switch. Construction provides strong resistance to static electricity
by having no soldered terminals.
■ Matrix adhesive used to create highly dust-proof
construction with good ventilation.
■ Lower profile, lighter weight, and crisp clicking
action.
■ OMRON’s unique circular contact action ensures
a high level of resistance to foreign matter.
RoHS Compliant
Application Examples
Use Dome Keys for the operating parts on various electronic
devices that require low-profile controls, as follows:
• Operating switches with few mounted parts above PCBs.
(Example: Camera operating buttons)
B3D-5112
• Small orders, where initial investment in Dome Arrays is not feasible.
(Example: Trial applications, commercial equipment, etc.)
• Applications requiring a single key only.
(Example: Reset buttons)
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-411
B3D
Specifications
■
List of Models/Ratings/Characteristics
Item
Model
B3D-4112
B3D-5112
Diameter of contact dome
4-mm dia.
Operating force (OF)
1.67±0.49 N {170±50 gf}
Releasing force (RF)
0.2 N {20 gf} min.
Pretravel (PT)
0.2±0.1 mm
Thickness
0.3±0.1 mm
Durability
500,000 operations min.
Switching capacity
10 mA, 12 VDC (resistive load)
(recommended minimum load: 1 mA, 3 VDC (resistive load))
Ambient operating temperature
−40 to 80°C (60%RH) (with no icing or condensation)
Ambient storage humidity
10% to 90% (at 40°C max.)
Contact dome
Stainless steel
Plating
Silver
Note:
5-mm dia.
1,000,000 operations min.
The Dome Keys are sold in units of 500 (20 sheets, with 25 Dome Keys per sheet). Order in multiples of 500 Dome Keys.
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B3D
B3D
Model Structure
Circular Contact
PET film (white)
(with matrix adhesive)
Stainless steel
contact dome
(circular contact)
Polyurethane
rubber film (with adhesive)
When contact dome keys are attached to the PCB, any PCB dust
or foreign particles will tend to collect in the center of the key
when it is pressed. Therefore, poor contact occurs easily in keys
that provide contact at the center point only.
The circular contact construction provides contact along the circumference of a circle, thus preventing poor contact by avoiding
the center point.
Conventional models
Contact dome resistant to
foreign matter (circular contact)
Matrix Adhesive
The surface structure of this adhesive has grid-shaped slits, as
shown in the following cross-sectional diagram. These slits provide both ventilation and dust-proofing, which is required for contact dome operation.
Cylindrical protrusion
Cover film
15 μm
Matrix (acrylic)
adhesive: 25 μm
Slits
Contact along
circle circumference
(circular contact)
Contact at center point
Recommended Contact Form
4-mm Diameter Contact Dome (B3D-4112)
5-mm Diameter Contact Dome (B3D-5112)
6.2 dia.
5.2 dia.
1.8 dia.
Gold-plated nickel
2.3 dia.
Gold-plated nickel
0.4
0.4
1.2 2.0
Single-side PCB
2.8 dia.
Resist (30 to 50 μm)
Resist (30 to 50 μm)
3.8 dia.
6.2 dia.
5.2 dia.
1.8 dia.
1.2 2.0
Single-side PCB
Gold-plated nickel
Multilayer PCB
2.3 dia.
Gold-plated nickel
Multilayer PCB
2.8 dia.
3.8 dia.
Recommended Operating Part Form
4-mm Diameter Contact Dome (B3D-4112)
5-mm Diameter Contact Dome (B3D-5112)
Resin
1 dia.
Entire
circumference: R 0.2
Note:
2
All units are in millimeters unless otherwise indicated.
Resin
1.5 dia.
Entire
circumference: R 0.2
B3D
B3D
Dimensions
Note:
All units are in millimeters unless otherwise indicated. Unless otherwise specified a tolerance of ±0.4mm applies all dimensions.
B3D-4112
Section A
(54)
25, 7.4 dia.
0.3
Section A enlarged
0.3
10
10
(54)
10
10
10
10
10
10
B3D-5112
Section A
(54)
25, 8.4 dia.
0.3
Section A enlarged
0.3
10
10
(54)
10
10
10
10
10
10
PCB Pattern Diagrams (Full scale)
■
B3D-4112
■
B3D-5112
3
B3D
B3D
Precautions
■
Correct Use
Note:
■
Be sure to read the safety precautions common to all Tactile Switches on pages for correct use.
Attaching to the PCB
Remove the Dome Key from the sheet using tweezers or a vacuum pick-up tool, and attach it above the contact on the PCB surface, which has been wiped clean in advance. Press down on the
top surface using an elastic material, such as urethane rubber,
and a force of 2.94 to 4.9 N {300 to 500 gf}. Place a positioning
mark (circle) on the PCB for easy positioning.
Make sure that the position of the Dome Key is aligned correctly
before use. Significant misalignment may result in short-circuits or
reduced sensitivity.
Note:
The recommended vacuum pick-up tool is the Hozan
P-835 Vacuum Pick with an M suction pad (7-mm dia.).
Do not reuse a B3D Dome Key that has been detached from the
PCB. Attach a new Dome Key to the PCB.
Do not touch the contact dome with bare hands, or with unclean
gloves. Doing so may damage the contact dome, which is the part
that comes in contact with the PCB.
■
Reflow Soldering
The Dome Key cannot withstand heat from reflow soldering.
Always perform reflow soldering before attaching the Dome Key
to the PCB.
■
Washing
Do not wash the Dome Key. The Dome Key is not water-resistant
and must not be exposed to water or other liquids.
ALL DIMENSIONS SHOWN ARE IN MILLIMETERS.
To convert millimeters into inches, multiply by 0.03937. To convert grams into ounces, multiply by 0.03527.
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