Delivering Quality Since 1952.

TECHNICAL ENGINEERING GUIDE

USER INTERFACESMembrane Switches, Touch Panels,

& Silicone Rubber Keypads

1DELIVERING QUALITY SINCE 1952.

TECHNOLOGY OVERVIEW

ENGINEERING OVERVIEW

Epec Engineered Technologies designs and manufactures customized, built-to-print, performance-critical products for all sectors of the electronics industry.

At Epec, we have a powerful story to tell a history of great achievements, world class talent, and innovative breakthroughs, but most importantly, a story of helping our customers deliver their high quality products to market, faster.

Epec has a sixty year history of reliability, on time delivery, and financial stability. Our continuous investment in people, technology, and new ideas are making it easier for our customers to do great work.

We have built the industrys leading supply chain platform and technology team, with Epec UL certified manufacturing operations in Shenzhen, Taipei, and North America, to seamlessly manage the needs of our customers product life cycles.

With more than 100 dedicated employees throughout North America and Asia, Epec EngineeredTechnologies has become one of the fastest growing companies in the Industry.

Epec has built one of the Industrys leading global supply chain and engineering platforms.

As one of North Americas leading PCB and built-to-print engineered product companies, Epecs annual capital expenditures are consistently among the highest in the industry.

Our investments are focused on world class engineering design systems, such as EpecDFx, and on continually improving our global technology platform, to accelerate our customers time to market.

Epec's technical engineering and manufacturing solutions have helped thousands of leading companies reduce their time to market.

With 24/7 North American engineering support we provide our customers the most in-depth feedback, with exact accuracy, eliminating delays and quality problems.

Epec can provide complete engineering and design services on all our engineered products, from concept through production in a quick and efficient time frame. With over sixty years of experience and knowledge across diverse industries, Epec has the ability to think outside the box and create innovative designs and solid manufacturing solutions.

Our technical staff will work with you to generate material specifications, product renderings, complete documentation and prototypes.

USER INTERFACES

2USER INTERFACES - MEMBRANE SWITCHES

MEMBRANE SWITCH DESIGN GUIDE

A membrane switch is a touch sensitive device created by the printing, cutting and laminating of precision thin film plastic materials. Low-voltage, low-current momentary electrical contact is made and retained by applying finger-tip force to the front surface of the switch.

Membrane switches are primarily utilized with microprocessor based control systems found in medical, communication, instrumentation and appliance products.

Membrane switch technology has become a reliable front panel solution where environmental concerns or frequent cleaning are an issue. The sealed nature of the technology coupled with its reliability and ability to offer tremendous aesthetic flexibility make it the solution of choice for many industries.

TYPES OF MEMBRANE SWITCHES

Non-Tactile Membrane SwitchesThe most reliable and economical membrane switch is the non-tactile type. However, they do not give the user direct feedback from the switch. Using a LED indicator or display change can sometimes overcome this drawback. Non-tactile switches also have the advantage of easily creating custom shapes and sizes of the active keypad areas.

Tactile Membrane SwitchesTactile membrane switches have a snap action that is clearly noticeable to the operator. Conductive stainless steel snap domes have the best action. They can also eliminate the need for a flexible upper circuit layer. To ease the final mating of the switch and avoid the possibility of a dome becoming inverted a .015" - .020" backing layer can be provided. Hydro formed polydomes offer a milder tactile response and a narrower operating temperature range then the metal dome.

Because of the relatively short travel of membrane switches, it is often necessary to provide users with some type of feedback. Feedback can be visual, audible, or tactile. Visual or audible feedback should be a consideration in the electronics design.

Domes can be added to a membrane switch to provide tactile feedback. There are two types of domes that we use in membrane switches, stainless steel and polyester. There is no significant difference in reliability between these two dome technologies.

Mixed PanelsNon-tactile and tactile switches can be mixed in the same panel. This can be desirable when a large active area is needed for a particular switch or perhaps hidden maintenance or programming switches.

PCB Backed Membrane SwitchesA printed circuit board can be used for the lower circuit. The board can provide structural support and incorporate numerous surface mount components. This assembly can be bonded to your PCB or sub-contractors can be utilized to provide this type of construction.

3USER INTERFACE

The Graphic OverlayThe appearance of the graphic overlay is integral to the operator's view of the equipment.

Nearly any colors can be produced. The finest line (or space between lines) that can be effectively printed is a .006" thickness. The maximum line screen is 230 LPI (lines per inch) for graduated halftones and process printing.

Embossing can be used with either tactile or non-tactile switches but pillow embossing alone does not give a tactile response.

Display WindowsIntegral display windows and LED indicators can be easily incorporated into the membrane switch design. Single point and block LED's have the least limitations. They will perform well with any of the material surface finishes. However, for greater diffusion a matte or textured surface finish is preferred. LED's cannot come through the active area of a tactile switch, although graphically they can be made to appear as a part of the switch.

Integral (surface mounted) single point LED's can be mounted onto the bottom layer lower circuit. A wide range of colors, including bi-color, are available. Termination can then be provided from the same connector tail as the switches, if the graphic layer is embossed to accommodate the LED's. The graphic does not need to be embossed if the LED termination is provided on a separate tail.

Digital windows can be designed to enhance the specific display that will be used. Texture will distort the appearance of displays that are not directly against the overlays. Matte and gloss finishes work best. Translucent filtering inks can be printed to improve a display's appearance.

For an LCD the window will remain un-colored. The matte (anti-glare) finish offers more scratch resistance than the gloss (clear) finish but may diffuse displays further then .060" away. A red LED display's appearance will be improved with the addition of either a RED or SMOKE GRAY color. Use red to achieve better readability in low light conditions or smoke gray when used in brighter conditions or with other colored LED's.

The concept is the same for use with Green or Yellow (amber) LED's. Use GREEN or AMBER yellow filters, respectfully, for low light conditions or smoke gray in brighter conditions.

DEADFRONTING (hidden until lit) is an additional option that can be included if the legends are against a dark background.

Selective TexturingSelective texturing is a screen-printed application of a scratch resistant surface hardcoat to the front face of the graphic overlay. The purpose is to improve the clarity of display windows or to visually emphasize specific areas.

A textured hardcoat can be applied to glossy or anti-glare material. This results in the best display windows. Another method is to apply a clear hardcoat to textured material.

USER INTERFACES - GRAPHIC OVERLAY

4MATERIAL SELECTION

A variety of overlay materials are used in membrane switch applications.

Polycarbonate is a commonly used material because it is easy to print on, die cut and emboss making it a very cost effective alternative. The disadvantage of polycarbonate is that it begins to show signs of wear sooner than some of the alternate materials.

In most applications polycarbonate overlays will last a minimum of 100,000 cycles during life cycle testing. Uncoated polycarbonate is also susceptible to damage from a variety of chemicals. If a polycarbonate overlay is going to be in an environment that will subject it to chemicals, a hardcoat should be used to protect the overlay.

Polyester is a more robust material that has superior life cycle and chemical resistance properties. In life cycle testing, polyester shows no signs of wear at 1,000,000 cycles.

Polyesterisalsomoredifficulttodiecutresultinginmore frequent reblading of steel rule dies.

Both polyester and polycarbonate are available with a variety of textures and hardcoats. In their uncoated glossy form both materials are very susceptible to scratching. For this reason we recommend that gloss materials receive a hardcoat.

USER INTERFACES - MEMBRANE SWITCHES

EQUIPMENT INTERFACE

Circuit Design - ConfigurationTracking lay-out can affect the reliability and ease with which the membrane switch can be manufactured. Therefore, the pin-out (i.e. the order in which the tracks exit the tail) should be left to the switch manufacturer when possible. The best pin-out can then be provided by the manufacturer to you as part of the design preparation process.

Switches can be connected using:

1. A common line configuration. (A common bus, ground, connects a number of different switches. This works well with a smaller number of switches and is generally an easier layout to engineer).

2. A matrix configuration. (An X-Y matrix for interconnecting columns and rows is created. This greatly reduces the number of tracks relative to the number of switches that the connector will require).

3. A mixture of the two.

5SHIELDING

Conductive inks or metalized (aluminum clad) polyester can be used to introduce an additional shield to the switch beneath the graphic layer.

Grounding can be accomplished with a separate tail or using the same connector as the circuitry. Alternatively a grounding tab can be created for connecting to a metal backing plate or support panel.

USER INTERFACES - MEMBRANE SWITCHES

VENTING

A pocket of air exists between the contacts of the switch. This air must be displaced when the overlay is depressed. Normally venting tracks to accommodate this displacement are designed between switches a part of the spacer layer by the switch manufacturer. This will result in a completely sealed switch and is perfect under normal atmospheric conditions.

PINOUTS

Theschematicorpinoutofaswitchmaybespecifiedbythecustomerifnecessary;however,aswithanycircuitlayout,themorefreedomweareallowedthemoreefficientlayoutwecanproduce.

This has the advantage of shorter development time and a simpler circuit layout, which could affect switch cost. Membrane switches can be designed with a common bus or in a matrix. Matrix layouts are desirable for keyboards with many keys to simplify the interconnect.

CONNECTOR TAIL

The position of the tail should be carefully planned as it could have substantial impact on the design of the membrane switch. A minimum clearance of .10 from tail edges for the tracks and a .040 minimum for each track must be allowed.

The tail is formed from the circuit layers. Therefore, no feature requiring a circuit track (i.e. switch or integrated LED) can be between the tail exit point and the edge of the panel. The easiest exit location thatcanbeproducedistobringthetailstraightoutofapaneledge(edgeexit).Thisworksfineifabezelwill cover the panel edge. Also easily accomplished is if the tail can exit just inside the panel's perimeter.

Ifthetailmustexitfromwithintheperimeter(insetexit)thenatailfillermustbeusedtoreplacethemissing circuit layers. Alternatively a WATER TIGHT NEMA 4 type perimeter seal can be utilized at an additional cost when necessary.

Amaleorfemaleconnectorcanbefittedtotheendofthetail.Exposedsilvershouldbecoveredwithcarbon to avoid silver migration and not be adversely affected by moisture.

6INTEGRATED LED'S

Surface mount LED's can be integrated into a membrane switch circuit. However they cannot be mounted within the active switch area. Bi-Color LEDs can also be utilized.

USER INTERFACES - MEMBRANE SWITCHES

ELECTRICAL PERFORMANCE

The large variety of membrane switch designs can make it difficult to outline a general set of specifications that covers all membrane switches.

Listed below are some basic performance specifications.

Loop Resistance: The loop resistance of a switch is a function of trace width and length. In most applications the maximum loop resistance is less than 100 Ohms.

Open Circuit Resistance: 50 Mega Ohms minimum Contact Rating: 100 Milliamps at 28 VDC Maximum Maximum Load: 1.5 VA Nominal Contact Bounce: 5 Milliseconds Nominal OperatingTemperature:-20Cto+75C

CUT-OUTS & PARAMETERS

Switch cut-outs (unless a bezel covers the opening) should be .030" overall larger than chassis openings. Allow at least .062" between cut-outs and active switch or window areas.

Normally the membrane overlay is made slightly larger than the layers beneath and recesses should be .010"largerallaroundtoassureaproperfit.

Careshouldbetakenthatgraphicsarenotobstructedwithanybezelsfittingaroundcut-outs.

LASER CUTTING

The various layers of a membrane switch can be cut out by using a numerically controlled laser. This technology offers two advantages. Tighter mechanical tolerances can be held, and no tooling is required.

While laser cutting is a more expensive process than die cutting, in many low and medium volume applications it is quite cost effective.

DRAWING NUMBER: n/a

DESCRIPTION: Membrane switch with graphic overlay & tactile domes

REVISION: -

Epec, LLC174 Duchaine Blvd., New Bedford, MA 02745P: 508-995-5171 F: 508-998-8694www.epectec.com

Circuit Matrix

switch

SW 1

SW 1

# 2# 1 # 3 # 4 # 6# 5 # 7 # 8 # 9 # 10 # 11 # 12

SW 2

SW 2

Pin 1

D1

D1

D2

D2

D3

D3 green

blue

orange

red

D4

D4

pinsLED

1.342"34.10 mm

0.342"8.68 mm

1.24

0"31

.50

mm

1.98

1"50

.31

mm

1.517"38.53 mm

0.78

9"20

.05

mm

0.344"8.73 mm

3X 0.302"7.67 mm

1.160"29.47 mm

1.539"39.10 mm

2.288"58.12 mm

5.024"127.62 mm

5.818"147.77 mm

6.154"156.32 mm

0.32

8"8.

32 m

m

1.14

6"29

.11

mm

2.31

1"58

.71

mm

3.25

3"82

.63

mm

3.78

1"96

.03

mm

0.00

0"0.

00 m

m

4.766"121.06 mm

5.268"133.81 mm

0.000"0.00 mm

2X 0.270"6.85 mm

(conductivesilver pad)

4X R 0.039"1.00 mm

EPEC date code

0.10

0"2.

54 m

m

2X metal domes

2X vent/retainer

exposed carboncontacts (front)

dielectric coat (front)

Asia brand connector(12-pin female)

Front View Assembly

Back View Upper Circuit Layer

Total part thickness = approx. .032 (.81mm)

0.84

7"21

.52

mm

2.32

4"59

.02

mm

0.364"9.25 mm

4.142"105.20 mm

7USER INTERFACES

CAPABILITIES - PROCESSES

Die CuttingUnusual shapesRounded cornersHard dies for metal partsSteel rule dies for flexible materialsThermal dies for vinyl substrate

EmbossingAdds three-dimensions to printing for unique

identification

LaminatingProtects printed nameplates, overlays, and

decalsSubsurface printing on flexible substrates can

be laminated on aluminum nameplates for i creased durability and protection

FormingBending to your specifications

MachiningFull in-house machine shopManufacture any rectangular, square, or round

metal nameplate, serial / VIN plate, or control panel without additional tooling charge.

Serial StampingSerial, vehicle identification numbers (VIN) or

model numbers can be stamped on flexible or metal substrates

Bar CodesBar codes can be printed on any nameplate,

serial / VIN plate, control panel, or graphic overlay, on any surface type

CAPABILITIES - MATERIALS

MetalsAluminumAnodized Aluminum (clear or black)Stainless SteelBrassMetalphoto

AdhesivesPermanent, pressure-sensitive acrylicSpecial adhesives for application to

powder coated surfaces or low surface energy plastic

Various foam thicknesses to adhere to rough surfaces or to dampen vibrations

FlexiblesPolycarbonatePolyester FilmVinylFoilAdhesive-Backed Litho PaperPolystyrene

8SCREEN PRINTED NAMEPLATES

Screen-printed nameplates are high quality and visually appealing for decorative, promotional or instructional purposes. They are typically recommended for mild indoor or outdoor applications where exposure to sunlight and durability are of prime concern. Screen-printed nameplates are used in a variety of commercial and industrial applications.

Screen Printed Nameplate Capabilities:Most sheet stock materials paper, plastic, films and metalsUp to 25" x 33" in size, larger sizes available upon reviewMaterial thickness from .002" to .250"Top surface or second surface printedPantone, Federal Standard or custom colorsEmbossing or stamped serial numbers on metal substratesMechanical fastener, studs or adhesive attachment methods3 to 5 year outdoor durability

Polycarbonate nameplates have superior mechanical strength, toughness and clarity. The polycarbonate nameplate can also survive extreme environmental conditions, such as high temperatures, chemical abrasions and corrosion. Polycarbonates are known for their dimensional stability, optical clarity, printability and graphic design freedom.

Polyesters various characteristics, such as high tensile strength, durability, clarity, resistance to abrasion and solvents, electric insulation, resistance to shrinking and stretching and is great for printing and die cutting.

USER INTERFACES - NAMEPLATES

ETCHED NAMEPLATES

Etched nameplates are recommended for harsh indoor or outdoor applications where exposure to weather, temperature extremes, sunlight, chemicals, solvents, fuels and lubricants is possible. Images are chemically etched into the substrate surface and could be filled with ink for added aesthetic and functional value.

They are particularly suited for industrial, marine, aircraft or automotive applications. Most metallic materials including aluminum, brass and stainless steel.

Etched Nameplate Capabilities:Material thickness from .008" to .125"002" standard etch depth with capability up to .005"Embossing or stamped serial numbersChemical and scuff resistantPantone, Federal Standard or custom colorsMechanical fastener, studs or adhesive attachment methods7 year minimum outdoor durability

9USER INTERFACES - TOUCH PANELS

MANUFACTURED TOUCH PANELS

Epec Engineered Technologies offers a full range of high quality touch panel technologies and sizes designed to fit a wide range of applications and LCD sizes.

Our product range consists of 4-wire, 5-wire, 8-wire resistive and capacitive touch panels. As a full service touch screen provider, we offer controllers and drivers that have been designed and developed specifically for our touch panel products.

In addition to our standard products, Epec can also design and manufacture custom touch screens to meet your unique LCD size and application. Our touch panels are designed and manufactured to the highest standards. Manufacturing occurs in class 10,000 cleanrooms. Throughout the process strict assembly procedures are followed to ensure total and effective quality control. Prior to shipping each touch panel is 100% electrically tested and visually inspected.

Epec delivers touch panel products to a variety of industries including: Medical, Retail and Industrial. Applications range from mobile communications products, industrial controllers, kiosks and household appliances.

Epec offers a wide variety of touch solutions for all types of environments and applications. Our technical and sales staff can assist you in selecting the best touch panel technology for you.

Resistive Product Construction Options:Film to FilmFilm to Film to Substrate (PC, Acrylic)Film to Glass

Touch Panel Benefits:Excellent Optical PerformancesFPC Tail TechnologyHigh ReadabilityAnti-Glare and Anti-Reflective CoatingsLong Product LifeTouch Accuracy

RESISTIVE TOUCH PANEL TECHNICAL SPECIFICATIONS

Material: ITOGlassThickness:.7;1.1;1.8;2.0;and

3.0mm ITO Film Thickness: 0.188mmSurface Hardness: 0-3HOptical/Light Transmission: >80%

Temperatures:OperationTemperature:-20-60CStorageTemperature:-20-70C

Life Expectance:4-wire/5-wire: >10,000,0008-wire: >1,000,000

Electrical:Operating Voltage: 5V Insulation Impedance: >20M ohms (DC25V)

Standard Size Range:Standard 4-Wire Sizes 2.8 21Standard 5-Wire Sizes 5.8 21Standard 8-Wire Sizes 8.4 21

10

USER INTERFACES - TOUCH PANELS

CAPACITIVE TOUCH PANEL TECHNOLOGY

Capacitive Touch Panels are all-glass touch panels with a transparent metallic conductive coating. An electrode pattern printed along the edges which distributes a low voltage field over the conductive layer.

When a finger touches the panel and draws a minute amount of current to the point of contact, creating a voltage drop. The current flow from each corner is proportional to the distance to the touch point.

The X/Y location of the point of contact is calculated by the controller and transmitted to the computer.

Capacitive Touch Panel Benefits:Excellent optical properties with a transmittance greater than 90%.Tempered glass with a scratch hardness of 6H.FPC tail offers low resistance, flexibility and robustness.High sensitivity, immediate response at the slightest touch.Touch panels are extremely durable. Withstanding water,

dust, harsh chemicals and grease.

Advantages:AccurateControl:Lessthan+/-1.5%linearitydeviation

and controller with excellent speed.FPC Tail Technology: FPC tail has low resistance and

is very flexible and robust.Durability: Our Capacitive touch screen withstand

contaminants such as grease, dirt, water, running liquid, harsh chemicals.

Performance: A transparent protective hard-coating minimizes reflection and maximizes light transmission. Hardened glass offers excellent scratch resistance and durability.

Specifications:Circuit: 5V DC35mALight Transmission: > 90%Contact: < 3msLinearity: 1.5%Surface Hardness: 6H Input Mode: Conductive stylus or bare fingerLife Expectancy: > 100 million Operating Temperature: 15 degree C to 70 degree CStorage Temperature: 50 degree C to 85 degree C

11

USER INTERFACES - SILICONE RUBBER KEYPADS

KEYPAD APPLICATION GUIDE

The Application Guide is an aid in the design and development of silicone keypads and specialty products. Silicone combines excellent feel, reliability and long life in the most rugged environment.Silicone keypads are used in a wide range of applications including medical, industrial, instrumentation and communications equipment.

Silicone material is supplied to the keypad industry in two forms, liquid and gumstock. Liquid silicone is atwopartsystemmixedasitisused;gumstockisaonepartsystemthathasashelflife.Bothareheat cured. Liquid silicone has the consistency of vaseline while gumstock is more like putty or clay. Silicone is measured for hardness in a shore A scale. The lower the number, the more silicone there is in the product and the softer it feels. The higher the numbers the less silicone and the more filler there is in the product and the harder it feels. Fillers and tensile strength.

Molding silicone rubber varies by process. The tools themselves are very similar and are usually made from P20 steel or 6061 aluminum. Wear on the tooling is usually negligible over the life of a project unless fillers that cause abrasion are added.

The types of molding processes are liquid, compression, transfer and extruding. Liquid molding is a closed loop system and molded under pressure using computer controlled repeatable equipment.Compression molding is open-air system similar to a waffle iron, material is hand cut and weighed.Transfer molding is a combination of compression molding and gumstock material pushed into a mold under low pressure. Extruding molding uses gumstock molding processes for continuous product such as tubing.

DESIGN RECOMMENDATIONS

Mechanical Keypad:1. Distance of a keys diaphragm to the edge of the keypads matte and any through hole is 0.040.2. Minimum key pitch dimension is 0.080. 3. Distance between two diaphragms is 0.040 (measured at base of diaphragm).4. The smallest blend radius of keys side wall to top of key is 0.010. 5. Typicalkeytaperis1dependingonkeyheight.6. Typical chamfer dimension on tactile keypad is 0.020. 7. Typical chamfer angle on tactile keypad is 45.8. Clearance between a bezel to a key is 0.012. 9. Typical base (mat) thickness is 0.040. 10.Standard air channel geometry is 0.080 to 0.125 wide by 0.010 to 0.013 deep. 11.Conductive contact area is 0.030 based on keypad application and size. 12.Sealing bead(s) top and/or bottom for environmental design requirements.13.Assembly aids via bosses and/or perimeter lip to hold rubber keypad to feature.

Through hole diameter is 0.025 Corner radius on matte and keys 0.015Corner radius on matte and keys 0.015

12

USER INTERFACES - SILICONE RUBBER KEYPADS

DESIGN RECOMMENDATIONS (continued)

Display/ LED Lightpipe/ Window Opening:1. Maximum depth of undercut for feature window opening is 0.250.2. Underside lip for window opening is the depth of undercut (#14) x 0.660.3. Minimum size for molded in silicone window/lightpipe is 0.060.4. Minimum thickness for molded in silicone window is 0.030.5. Minimum height for molded in silicone lightpipe is 0.030.6. Minimum distance from window/lightpipe to and edge is 0.030.7. Min / Max wrap around underside is 0.060 to 0.500. Deeper8. wraps may be considered depending on design.9. Sealing rib diameter is 0.030.

Keypad Wrap - Around Design:The wrap-around design offers unique capabilities in silicone rubber. Using liquid injection process, one can create hand held units similar to complete plastic cases. With the wrap-around feature, an appealing product can be designed with all the protection requirements for harsh environments.

TYPICAL PART TOLERANCES < 0.400 0.004 0.401 - 0.800 0.006 0.801 - 1.200 0.008 1.201 - 1.600 0.010 1.601 - 2.000 0.012 > 2.001 0.6%

RECOMMENDED GRAPHIC PARAMETERS

Graphic Design:1. Solid colors can be screened up to the edge of flat keytop.2. On curved keytops, solid colors can be screened up to 0.015 to the tangent point of the outer

radius.3. Distance from edge of the keypad to legend is 0.015.4. Distance of matte legends to key is dependent on key height.5. Minimum line weight for legends is 0.007.6. Minimum text height is 0.050.7. Color consistency is within 1 Delta for production run. Typical screening tolerances are 0.015.

Keytops Considerations for Graphic Screening:1. Minimum radius allowable for printing over the edge is 0.375.2. On legend overrun onto matte surface, a minimum transition radius of 0.010 is required.3. Maximum curvature depth for concave keytops with a minimum radius of 0.375 is 0.060.4. Maximum curvature height for convex keytops with a minimum radius of 0.375 is 0.060.

13

USER INTERFACES - SILICONE RUBBER KEYPADS

TYPICAL DRAWING INFORMATION

Overall Keypad Size Key Spacing Keypad Mat Thickness Actuation Force (grams) Keytop Dimensions MaterialSpecifications(durometer) Mounting Hole Details Legends & Color(s) (PMS numbers, etc.) Mounting Boss Details Keypad Color Radii Dimensions (keypad and buttons)

ACTUATION FORCES OF CERTAIN KEY SHAPES & STYLES

Name OfShape Cone Double Cone Bell/Cone Cone Double Cone Flat

Profile OfShape

Force Vs.Travel

TypicalActuationForce

20-250 Grams

20-250 Grams

20-200 Grams

20-150 Grams

20-150 Grams

20-100 Grams

Rubber keypads can be designed so that they achieve a positive tactile response when the operator depresses the keypad. To achieve good tactile feel that is inherent in the rubber keypad the keypad should have at least .060 of travel and should have an actuation force of between 50 and 170 grams.

As an alternative, a tactile layer can be incorporated in between the rubber keypad and the circuitry layer, which will enable a good tactile feel even with small keys and minimal travel distances. This option, which utilizes either stainless steel domes or formed polydomes, does add cost to the project.

Rubber keypads should be designed with a minimum return force of 30 grams in order to eliminate the potential of sticking keys.

TACTILE RESPONSE

F = Return Force A = Actuation force C = Contact force

Snap Ratio = (A-C)/A) A = 350 grams C = 230 grams (350-230)/350=0.343)

14

USER INTERFACES - SILICONE RUBBER KEYPADS

KEYPAD DESIGN

Physical Properties of Silicone RubberTypical Physical Property Carbon Conductor Silicone InsulatorSpecificGravity@72C 1.18 1.17Durometer Hardness (Shore A) 65 5 30-80 5Tensile Strength (KG/CM) >50 >70Elongation (%) >100 >250Tear Strength (KG/CM) >9 >12Linear Shrinkage (%) 3 - 5 3 -4.5Volume Resistivity (Ohm/CM)

15

USER INTERFACES - SILICONE RUBBER KEYPADS

RUBBER KEYPAD TERMINOLOGY

Actuation Force: The force required to collapse the web of a rubber keypad in conjunction with polydome, metal dome, mechanical switch or rubber only.

Air Channel: Air path(s) on the bottom of rubber keypads that allows for air passage when rubber is depressed.

Alignment Hole: Through hole in rubber keypad that is used to position keypad in enclosure.

Base Matte: Silicone sheet material that joins all keys on a rubber keypad. Also known as mat.

Bezel: The faceplate or cover, typically plastic or metal, used to secure a keypad to a printed circuit board or switch.

Bosses: Small posts used for positive alignment of rubber keypad in bezels or assemblies.

Compression Set: The measurement of a materials ability to recover its original size and shape after compression under prescribed conditions.

Conductive Rubber: Silicone keypad impregnated/coated with conductive material.

Color Matching: The visual and electronic analysis of a mixed silicone rubber material compared to a supplied color sample.

Diaphragm / Web: The thin hinged area that permits a rubber key to flex.

Durometer: A measurement range of hardness for silicone rubber.

Key Height: The measured distance from the bottom of a keypad (base matte) to the top surface of a key.

Legend: Printed graphic (symbol, letter or number) on the top of the rubber surface.

Life: The number of actuations realized before the rubber diaphragm/web ruptures.

Reversed-Out Graphics: Graphics that allow rubber color or masking color to be seen through top surface printing on keypad.

Positive-image Graphics: Single or multi-color printing on top of key surface.

Stroke / Travel: Distance from the contact surface of a rubber part to a surface.

Swell: The increase in volume of rubber when in contact with petrochemicals for a determined period.

Tactile Feel: The response of rubber while depressing. For tactile rubber keypads, it is a critical function of the diaphragm web geometry.

Tear Strength: The tear strength is a measure of the resistance of rubber to tear forces. The tear strength is calculated by dividing the maximum force load by the thickness of the rubber.

Wear or Abrasion Resistance: The resistance of a particular ink or coating to manual wearing. The testing process is usually a Norman tester with the number of cycles legends can perform before wear is noticeable.

16

USER INTERFACES

USER INTERFACE PRODUCTS

Membrane Switch Products Include: Embedded LED Construction Dome Embossed Rim Embossed Non Tactile (Flat Buttons) Various Material Finishes

Graphic Overlay Products Include: PET Labels Polydomed Construction (Raised Buttons) Custom Shapes and Designs Printed and Laser Etched Graphics Various Material Finishes

Rubber Keypad Products Include: Standard Keypads Multi color Keypads Injection Molded Laser Etched Epoxy Coated

17

USER INTERFACES

ARTWORK GUIDELINES

Support Software

Epec Currently Supported Software: Other Acceptable Formats:AutoCAD (.dwg & .dxf) Adobe Portable Document File (.pdf)Adobe Illustrator (.ai) Encapsulated Postscript (.eps)Adobe InDesign (.indd) Scalable Vector Graphics (.svg)

Tagged Image File (.tif or .tiff)Adobe Photoshop (.psd)

Many other formats exist for electronic file transfer. If you have a file type other than what is listed above please send us what you have and we will do our best to accommodate your format.

ResolutionA minimum resolution of 300 dpi is recommended. Lower formats may result in poor quality reproduction.

Text & FontsAll text needs to be converted to outlines to prevent character or font substitution. Convert the fonts to "curves" (when using CorelDraw) or "Create Outlines" (when using Adobe Illustrator).

If you do not have this capability please include any associated font files along with your graphic file.If fonts are not included or converted to curves we cannot guarantee the graphics will match your intended design.

ColorArtwork should be submitted as spot colors (pantone colors).Please provide the pantone color numbers being used with your artwork file.

Linked GraphicsIf you are using a program that allows for linked images, rather than embedded in the file, please provide linked graphics separately.

BleedsElements that extend beyond the edge cut (bleeds) should extend a minimum of .125" beyond the edge cut.

18

USER INTERFACES

ADDITIONAL ENGINEERED PRODUCTS

USER INTERFACESMembrane SwitchesRubber KeypadsTouch PanelsTactile & Non-TactileKeyboard AssembliesLEDs, Cutouts & Display Windows

GRAPHIC PRODUCTSOverlays & FaceplatesRoll LabelsRigid Metal NameplatesSerial Number TagsBarcode & QR CodesPrinted Cut PlasticUrethane DomingDigital & Screen Printing

FANS & MOTORSAC/DC Axial FansMotorized Impellers Industry Leader in Electronically

Commutated Motors

CUSTOM BATTERY PACKS Industry Leading Design Team

NiMH, NiCH & Sealed Lead BatteriesLi-Ion, Li-Pol & LFP

Smart Battery TechnologyCustom Enclosures

IATA, DOT & UL TestingBattery Chargers

FLEXIBLE & RIGID FLEX PCBSPrototype, Low-High Volume & Roll to Roll

Polyimide & Polyester Materials IPC 2223C Constructions

Coverlay & Flexible SoldermaskStiffeners, PSAs & Strain Reliefs

Controlled Impedance & ShieldingDesign & Gerber Layout Support

RIGID PRINTED CIRCUIT BOARDSLeader in Quick-Turn PCB's

Up to 18 LayersFine Lines & Spaces

Heavy CopperThermal Clad

Many RoHS and RF Materials

Blind & Buried Via'sControlled Impedance

Visit Our Website @ www.epectec.com

AMERICA'S OLDEST. A HISTORY OF INNOVATION.

CONTACT US

The 60-year story of Epec is connected to the development of the PCB and the electronics industry.

Epec, through the merger of Electralab and Printed Electronics Corp (EPEC), are proudly two of the five founding members of the IPC, the 2,900 member trade association supporting the $1.5 trillion global electronics industry.

From pioneering innovation in the PCB Industry with R & D, training and setting professional core values, the legacy of Epec has now passed to a new generation of very bright young people, but still continues the great tradition of imagination.

In incubating new technologies, the Epec team continue breaking new frontiers in engineering, and enjoying exponential growth in related sectors of electronics, with custom battery packs, membrane switches, rubber keypads, and EC fans and drives.

Our knowledgeable staff has many years of experience in the industry. We welcome the opportunity to put our skills to work for you! Please contact us with any questions or requests.

North American Headquarters174 Duchaine Blvd.New Bedford, MA 02745Toll Free: (888) 995-5171Tel: (508) 995-5171Fax: (508) 998-8694

Contact Us By Email:Sales sales@epectec.comQuotes quoting@epectec.comEngineering engineering@epectec.comQuality quality@epectec.com

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