SW_Cat_Email-html.html

Custom Engineered

Solutions for Harsh

Environment Survivability

Membrane

FEBR

2007

SW-CAT-02-07

DOMESTIC AGENTS

For a complete list of Bergquist sales representatives in the U.S. contact
The Bergquist Company: 1-800-347-4572.

INTERNATIONAL SALES OFFICES

HONG KONG

The Bergquist Company
Asian Headquarters
Room 15, 8/F
Wah Wai Industrial Centre
No. 38-40,
Au Pui Wan Street
Fotan, Shatin, N.T.
Hong Kong
Tel: 852-2690-9296
Fax: 852-2690-2344

THE NETHERLANDS

The Bergquist Company
European Headquarters
Bramenberg 9a
3755 BT Eemnes
The Netherlands
Tel: 31-35-5380684
Fax: 31-35-5380295

CHINA

The Bergquist Company
China
Rm. 7C
Aihe Mansion
No. 629 Ling Ling Road
Shanghai, China 200030
Ph: 86-21-6464-2206
Fax: 86-21-6464-2209

GERMANY

Bergquist ITC GmbH
Haderslebener Str. 19A,
D-25421
Pinneberg
Tel: 49-4101-803-230
Fax: 49-4101-803-100

SOUTH KOREA

The Bergquist Company
Korea, Ltd.
#5303 Dongil Technotown
Anyang 7 Dong
Manan Ku, Anyang Si
Kyunggi Do
South Korea, 430-817
Tel: 82-31-448-0382
Fax: 82-31-448-0383

ENGLAND

Bergquist UK Ltd.
Unit 27 Darin Court
Crownhill Ind. Est.
Milton Keynes MK80AD
Tel: 44-1908-263663
Fax: 44-1908-263773

AUSTRALIA
AUSTRIA
BELGIUM
BRAZIL
CANADA
CHINA
DENMARK
FINLAND
FRANCE

HOLLAND
HONG KONG
ISRAEL
ITALY
JAPAN
MALAYSIA
MEXICO
NEW ZEALAND
NORWAY

PORTUGAL
RUSSIA
SINGAPORE
SPAIN
SWEDEN
SWITZERLAND
TAIWAN
THAILAND
TURKEY

INTERNATIONAL AGENTS

Corporate Headquarters and Sales Office:

18930 West 78th Street

Chanhassen, MN 55317

Toll Free: (800) 347-4572 • Main: (952) 835-2322 • Fax: (952) 835-0430 • www.bergquistcompany.com

Thermal Products •

Membrane Switches

• Touch Screens • Electronics • Labels and Graphic Overlays

Bergquist Switches

Bergquist: Your Single Source for
Custom Membrane Switches

The Bergquist Company is the leader in engineering and manufac-

turing of high quality, custom membrane switches for a wide vari-

ety of applications, including:

•

Automotive

•

Medical instruments

•

Consumer/industrial electronics

•

Business equipment

•

Commercial appliances

•

Recreation products

Materials – The Key to
Bergquist Success

We began building membrane switches at a time when many companies’

switches were failing in the field. Our engineers and scientists realized that

the key to making durable membrane switches is to understand not only

the electronics of the switch, but also the chemistry of the materials, the

interaction of layers, and how the combinations work in harsh environ-

ments.

Today, our laboratory facilities in Minnesota are used to research material

compatibility in membrane switches and develop processes that improve

switch performance, durability and reliability.

In the pages that follow, you'll see in detail how Bergquist HeatSeal

mem-

brane switches provide you with the most cost-effective, most durable

solutions available.

Customer Focused

The Bergquist Company is clearly and

consistently focused on our customers.

Ensuring total customer satisfaction with

our products and relationships has always

been our company’s primary objective.

Our knowledgeable, courteous and diligent Customer Service

Representatives work with our customers to develop demand manage-

ment programs that allow us to customize manufacturing schedules to suit

individual customer requirements.

Delivery

We schedule consistent on-time deliveries using:

•

Customized demand-management systems

•

Forecasts

•

Kan Bans

•

E-Scheduling

•

Material authorizations

•

Annual contracts

•

Any other customer-preferred methods

Our manufacturing facility utilizes an MRPII system to ensure on-time deliv-

ery of your product.You get what you want, when you want it!

Quality

Every aspect of Bergquist engineering and manufacturing is firmly

anchored in our commitment to quality. Membrane switch manufacturing

facilities are ISO 9001:2000 certified.

High Standards

Bergquist is a company whose high standards embrace product quality,

integrity, confidentiality and partnering. Rely on Bergquist for professional

and knowledgeable customer service.

Ready to Serve You

Whether you are developing a new product requiring a membrane

switch, or seeking a different or second source for an existing product, we

invite you to switch to Bergquist by calling us toll-free today at (800) 347-4572.

The Bergquist Advantage

Why Bergquist is Better:
HeatSeal

Technology

Bergquist manufactures membrane switches using HeatSeal, a pro-

prietary dry film adhesive bonding technique developed for appli-

cations where conventional membrane switches often fail. Key

benefits of HeatSeal include:

•

Bonds top and bottom circuit layers together

•

Protects the electrical integrity of your switches

•

Provides permanent seal from outside environment

Inadaquate sealing of switch layers is a major cause of failure. Moisture,

temperature extremes and chemicals are typical enemies of standard PSA

(pressure-sensitive adhesive) membrane switches.To overcome this issue,

Bergquist’s exclusive HeatSeal fabrication process thermally bonds switch

layers together with heat and pressure.The lamination strength is superi-

or to pressure-sensitive adhesive construction and there is no need to

externally vent the spacer layer. The result is a complete seal which pro-

tects the electrical integrity of your membrane switch.

Bergquist developed the HeatSeal process so you can design a membrane

switch for almost any environment. Bergquist membrane switches oper-

ate under water, in dust and dirt, in high and low temperature extremes,

and in critical-reliability environments such as hospitals where harsh clean-

ers are commonly used. No other membrane switch manufacturer has

developed a fabrication technique as durable as the Bergquist HeatSeal

membrane switch.

Graphic Layer

Graphic Adhesive

Top Switch Circuit Layer

HeatSeal Spacer Layer

Bottom Switch Circuit Layer

Rear Adhesive

What sets Bergquist membrane switches ahead of the competition is our
exclusive HeatSeal spacer layer. The strength and impenetrable lamination
created by the HeatSeal process protects the delicate switch circuitry from
harsh environments, solvent attack, fluid ingression and electrostatic
discharge (ESD). See facing page for details.

Bergquist Switches

HeatSeal Holds Up
Under Pressure

PSA Switches

Typical air distribution within a pressure sensitive adhesive (PSA) mem-

brane switch at time of manufacture is shown in Figure 3.The buildup of

air pressure differential as the membrane switch is raised to an elevation

of 40,000 feet is shown in Figure 4. The air pressure within the switch

becomes great enough to force its way through the micro fissures in the

PSA until the air pressures between the switch and the environment have

equalized.

The resulting distribution of air within the switch once it has returned to

a normal elevation is shown in Figure 5.The memory within the polyester

does not have enough force to draw air back into the switch cavities.The

end result is a collapsed, electrically shorted switch.

Bergquist HeatSeal Switch Construction

Figure 6 depicts the typical distribution of air within a HeatSeal membrane

switch at time of manufacture.

The buildup of air pressure differential as the HeatSeal switch is raised to

an elevation of 40,000 feet is shown in Figure 7. The air pressure buildup

will increase the actuation force of the switch at elevation. However, the

force of the air pressure cannot overcome the bond strength of HeatSeal.

The resulting, unaffected distribution of air within the HeatSeal membrane

switch once it has returned to normal elevation is shown in Figure 8.

FIGURE 3:

PSA Switch - Air Pressure @ Equilibrium

FIGURE 6:

HeatSeal Switch - Air Pressure @ Equilibrium

FIGURE 4:

PSA Switch - Air Pressure @ Higher Altitude

FIGURE 7:

HeatSeal Switch - Air Pressure @ Higher Altitude

FIGURE 5:

PSA Switch - Air Pressure @ Normal Altitude

FIGURE 8:

HeatSeal Switch - Air Pressure @ Normal Altitude

10X microscopic view of HeatSeal material shows solid nature of the material,
thus making it impervious to leakage under higher or lower air pressure.

10X microscopic view of PSA material shows air gaps inherent in the nature
of the material, thus making it susceptible to leakage under higher or lower
air pressure.

These illustrations show the overall protection strength of Bergquist HeatSeal.
HeatSeal’s strength and impenetrable lamination protects the delicate switch
circuitry from harsh environments, solvent attack, fluid ingression and electro-
static discharge (ESD).

Testing

Testing Programs

Anyone can

claim to be the best. At Bergquist, we can prove it!

Our commitment to testing before, during and after production is

among the reasons why Bergquist HeatSeal membrane switches

are known throughout the world for their high reliability.

While PSA switches are adequate for some applications, engineers

cannot always identify what the end use environmental conditions

will be. Bergquist HeatSeal switches are designed, manufactured

and tested to hold up in the toughest environments imaginable.

Bergquist Testing Includes:

Materials

Bergquist lab technicians use the latest technology and equipment to test

materials before and after manufacturing to maintain quality control.

Material from suppliers is checked regularly to identify any changes that

may affect the switches. In addition, TGA (Thermo Gravimetric Analysis)

equipment can be used to identify the exact “fingerprint” of a material.

Other equipment is used to measure the adhesion between switch layers,

and to simulate environmental conditions (see HeatSeal testing, pages 5-8).

Switch Actuation

Specialized devices operate switches through millions of actuations to test

reliability. Other testing conducted in the Bergquist laboratory includes

switch functional performance testing, high temperature humidity testing,

and low temperature testing on switch packages.

Electrical

A custom software program logs the electrical resistance of each key on

every switch manufactured. This information is stored in a database for

each customer. A barcode on each switch can be scanned to call up

detailed switch information.

-25

100

Chamber Temperature

(Celsius)

lbs/in

Testing

Temperature Endurance Test

Test Purpose

To determine the effect of temperature on the bond between the

layers of a membrane switch. In this test we evaluate switch bod-

ies constructed using a Bergquist HeatSeal spacer and a pressure

sensitive acrylic spacer.

Method

Bergquist uses test method ASTM D-1876-72 for measuring peel resist-

ance between the switch layers. Samples are prepared using the following

spacer materials and cut into one-inch-wide specimens for peel testing:

A) .005" Mylar™ polyester film (top), .009"

pressure sensitive acrylic spacer, .005"

Mylar polyester film (bottom).

B) .005" Mylar polyester film (top), .008"

HeatSeal spacer, .005" Mylar polyester

film (bottom).

Three (3) samples of each construction are

prepared for testing at eight temperatures:

-25, 0, 25, 50, 60, 70, 80 and 100°C.

Each test specimen is placed in the grips of an Instron Test Machine (see

Figure 9) and conditioned at the specified temperature for five (5) min-

utes.The top and bottom layers are then separated at a rate of ten (10)

inches per minute.A chart recorder is used to record load versus displace-

ment.The average peel strength of each specimen is determined by meas-

uring load at each half inch of separation until ten (10) readings are taken.

Peel strengths are reported in units of pounds per inch width.

Summary

The data demonstrates that the peel adhesion of PSA adhesive varies

greatly with temperature, while HeatSeal peel adhesion remains relatively

stable (see Figure 10). At temperatures exceeding 50°C, PSA is suscepti-

ble to delamination through both internal and external stresses inherent

in membrane switch constructions. Examples of these forces are interfer-

ence fits, differences in coefficients of thermal expansion, and upward force

due to connector/tail placement.Any delamination of the switch layers will

leave the circuit vulnerable to fluid ingression and/or contamination (i.e.

electrical failure).

FIGURE 9:

Instron Test Machine

Bond Strength vs. Temperature

FIGURE 10:

Peel adhesion at temperature

HeatSeal

Pressure Sensitive Adhesive (PSA)

Testing

General Purpose Cleaners Test

Test Purpose

To determine the effect of common household cleaners on the

switch bodies of membrane switches constructed with a Bergquist

HeatSeal spacer and with a pressure sensitive acrylic spacer.

Set Up

Standard 3 x 4 matrix switches 2.6" x 3.0" with 3" tails are used for test-

ing. All switches are constructed one month prior to any testing. Spacers

tested are as follows:

1) Bergquist HeatSeal spacer – .008" total thickness (.005" base poly-

ester with .0015" of HeatSeal adhesive on each side).

2) Pressure sensitive acrylic spacer – .009" total thickness (.005" base

polyester with .002" of acrylic adhesive on each side).

Pre-testing of all switches is performed by following these steps:

1) 24-hour immersion in a solution of water with .2% by volume of

soap added.

2) Insulation resistance readings are then taken on each switch at 100

VDC. A minimum of 1 mW insulation resistance is required for each

switch to enter the testing phase.

Solutions

Eight beakers are each filled 3/4 full with a cleaning solution and four

drops of green dye.The cleaning solutions are:

A) 409

B) Fantastik

C) Dow

Bathroom Cleaner

D) Lysol

Tub and Tile Cleaner

Parameters

Samples of each switch type are immersed in each of the four solutions.

Each group of parts is then placed in an airtight container, to reduce evap-

oration, for a period of 180 days at room temperature.

Results (Refer to Figure 11)

•

HeatSeal spacer – no visual degradation of the switch occurred in any

of the switches.There were no measurable changes in the insulation

resistance of any of the parts (see Figure 12).

•

Pressure sensitive acrylic spacer – results varied with

each solution:

A) 409 – ingression and dissolving of the PSA adhesive occurred uni-

formly around the perimeter of the switch. 1st failure of insulation

resistance occurred on day 20 (Figures 13 and 14).

B) Fantastik – ingression and dissolving occurred as above. Failure

occurred on day 42 (see Figure 15).

C) Dow Bathroom Cleaner – ingression and dissolving occurred as

above. Failure occurred on day 56 (Figure 15).

D) Lysol Tub and Tile Cleaner – ingression and dissolving occurred as

above. Failure occurred on day 92 (see Figure 15).

FIGURE 11:

Insulation Resistance Over Time

10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 Test

Terminated

1 X 106 OHMS

INSULATION RESISTANCE

D A Y S

E L E C T R I C A L S H O R T F A I L U R E

PSA Switch, 409, switch to solution insulation resistance, failure in 20 days avg.

PSA Switch, Fantastik, switch to solution insulation resistance, failure in 42 days avg.

PSA Switch, Dow Bathroom Cleaner, switch to solution insulation resistance, failure in 56 days avg.

PSA Switch, Lysol Tub and Tile Cleaner, switch to solution insulation resistance, failure in 92 days avg.

HeatSeal Switch

, 409, switch to solution insulation resistance.

HeatSeal Switch

, Fantastik, switch to solution insulation resistance.

HeatSeal Switch

, Dow Bathroom Cleaner, switch to solution insulation resistance.

HeatSeal Switch

, Lysol Tub and Tile Cleaner, switch to solution insulation resistance.

409

is a registered trademark of The Clorox Company. Fantastik

is a registered trade-

mark of SC Johnson Company. Dow

and Bathroom Cleaner

are registered trade-

marks of Dow Corning Corporation. Lysol

and Tub and Tile Cleaner

are registered

trademarks of Reckit Benckiser, Inc.

Testing

General Purpose Cleaners Test Results

Observations

The ingression and dissolving of the PSA adhesive was consistent around

the perimeter, however at various stages some smaller areas of increased

ingression would appear.These inconsistencies in ingression advancement

point to inconsistency in lamination caused by air voids between the adhe-

sive and circuit layer. These voids enhance the cleaners' ability to ingress.

Summary

This simple test shows that 409, Fantastik, Dow Bathroom Cleaner and

Lysol Tub and Tile Cleaner are aggressive towards pressure sensitive acrylic

adhesive. These same cleaners have no effect on the Bergquist HeatSeal

switch construction.

FIGURE 12:

HeatSeal construction switch soaked in 409

FIGURE 13:

PSA construction switched soaked in 409

FIGURE 14:

Close-up of fluid ingression into key area (PSA switch soaked in 409)

FIGURE 15:

PSA construction switches soaked in other cleaners

Testing

Gasoline Test

Test Purpose

To determine the effect of gasoline on the switch bodies of membrane

switches constructed with a Bergquist HeatSeal spacer and with a pres-

sure sensitive acrylic spacer.

Set Up

Standard 3 x 4 matrix switches 2.6" x 3.0" with 3" tails are used for test-

ing. All switches are constructed one month prior to any testing. Spacers

tested are as follows:

Bergquist HeatSeal spacer

- .008" total thickness (.005" base polyester

with .0015" of HeatSeal adhesive on each side).

Pressure sensitive acrylic spacer

- .009" total thickness (.005" base

polyester with .002" of pressure sensitive acrylic adhesive on each side).

Pre-testing of switches is performed as in the General Purpose

Cleaners Test.

Results

HeatSeal spacer

- After 14 days of immersion in gasoline there were no

visual signs of degradation. There were no measurable changes, through-

out the 14-day duration of the test, in the insulation resistance measure-

ments.

Pressure sensitive acrylic spacer

- Severe dissolving of the PSA adhesive

and ingression of the gasoline occurred within the first 2 hours of the test.

After 2 hours the parts had failed the insulation resistance test. After four-

teen days switches were completely delaminated with only some gelati-

nous masses of PSA adhesive left.

FIGURE 16:

PSA switch soaked in gasoline and green dye for 10 hours indicates sub-

stantial fluid ingression and switch delamination.

FIGURE 17:

HeatSeal switch soaked in gasoline and green dye for 10 hours shows no

fluid ingression or switch delamination.

Engineering

Leading Edge Technologies

Bergquist uses leading-edge CAD systems to engineer your cus-

tom membrane switch. Our CAD professionals can import your

engineering files or we can create new ones from your specifica-

tions and prints. All switch layers are engineered on the CAD sys-

tem to ensure consistent base-line accuracy for all production

operations.

Individual layers from CAD drawings are used for screen making

and die board making, and are used to drive our laser cutter for

prototypes and small production runs.

Engineering

Involve our engineering staff early in your design-build process to benefit

from our switch design expertise. Our engineers are accessible and eager

to assist you in ensuring that your circuit and graphic designs meet our

manufacturing capabilities. For example, there should be .125" between

any exposed edge and the first trace of silver to properly HeatSeal switch

layers. Also, circuits should be designed to avoid dielectric jumpers and still

achieve proper pin-out. Involve us early; we can help in many ways.

Operating Environment

The environment your switch will be operating in often determines the

switch material and its construction. Polyester has a long flex life and is

resistant to solvents. Polycarbonate is available with a tough matte texture.

In many cases a hardcoat can be applied to either material for added pro-

tection. For chemical, high moisture, dusty and variable temperature envi-

ronments (as well as unknown or uncontrollable environments), we rec-

ommend HeatSeal construction.

Graphic Life

The type of material, its thickness and the embossing of keys can all affect

the life of the graphic layer. Polyester is recommended for long flex life.

Our life testing indicates polyester outlasts polycarbonate. Embossing and

contact with chemicals may also reduce polycarbonate graphic life.

Power Levels

Most membrane switches are used in logic level power applications.

Generally, screened silver inks are used with switching loads under one

watt. Copper foil laminate may be used when switching loads are one watt

and above.

Materials - The Key to Bergquist’s Success

We began building membrane switches at a time when many

companies’ switches were failing in the field. Our engineers and sci-

entists realized that the key to making durable membrane switches is

to understand the chemistry of the materials, the electronics of the

switch, the interaction of the layers, and how the combinations work

in a harsh environment.

Today, our laboratory facilities in Chanhassen, Minnesota are used to

research materials compatibility in membrane switches, and develop

processes that improve switch performance, durability and reliability.

Research & Development

Innovation and New Product Development
are the Lifeblood of the Company.

Bergquist invests in research and development including an exten-

sive developmental laboratory and engineering department where

new products are researched, developed and tested.

Innovation

Many proprietary and patented products originated in Bergquist
laboratories, including Thermal-Clad, variations of Sil-Pad materials
and the HeatSeal adhesive used in Bergquist membrane switches.

Development

At Bergquist, developing new and innovative quality products is no
accident. Bergquist follows a proven development methodology for
new product and process development. From the first stage of
development to high volume manufacturing, Research and
Development is involved to assure Bergquist products meet our
customers’ needs.

Capabilities

Located in the Chanhassen, MN headquarters facility, the Bergquist
R&D laboratory and engineering department is home to a full staff
of chemical engineers, manufacturing engineers and laboratory
technicians working to improve existing products and dream up
new ones.

Partnership

Partnering with our customers to develop unique solutions to spe-
cific market needs enables Bergquist to be a valuable and cost-
effective supplier.

Manufacturing

Accuracy and Quality

Screen Making

Our state-of-the-art CAD system outputs directly to finished film via a

photo laser imagesetter. Finished film is then exposed directly to screen

stencils. All film layers are registered using optical equipment to ensure

consistently accurate registration of screened circuitry and graphics. For

accuracy, Pneumatic screen stretchers are used and each screen is tested

for uniformity of pressure before use.

Screen Printing

Our screen printing facility is ISO 9001:2000 certified and a model of

cleanliness, precision and efficiency. Automatic, semi-automatic and

manual presses are matched to each switch project for maximum produc-

tivity and cost-efficiency.

The Bergquist Company uses a computerized color matching system to

formulate custom colors for your membrane switch.This system helps us

make the necessary color adjustments needed to provide colors that will

match the rest of your assembly from start to finish.

Process Controls

Bergquist employs a wide variety of process control tools and

techniques including:

•

Variety of SPC controls to insure repeatable product quality

•

Heat stabilization of circuit and graphic substrate materials

•

Statistical monitoring of screen tension

•

First article inspection of each screened layer

•

Belt speeds and UV light output are monitored using SPC

techniques for accurate process control

•

UV hardcoats are cured using a Linde nitrogen curing system

Whether it’s screened silver circuits or graphics, accuracy and qual-

ity are first and foremost at Bergquist. Our state-of-the-art screen

making and printing facilities feature the latest technologies and

professionals who know how to use them.

Manufacturing

Every Step is Important

At Bergquist, every step in our manufacturing process, including the

embossing, die cutting and assembly processes described here, is

critically important to achieving the high standards that we and our

customers expect.

Polyester Dome Forming and Graphic Embossing

Our specialized multi-station embossing and dome forming presses allow

the operator to work quickly through consecutive operations. Our in-

house dome forming equipment provides consistent tactile feel from

dome to dome and lot to lot.

Die Cutting

At Bergquist, craftsmanship and technology work seamlessly together to

deliver a higher quality solution. Our premium hardwood die boards are

precision cut on a CNC laser cutter from approved CAD files. In our com-

plete in-house die shop, experienced steel-rule die makers ensure long

production life, accuracy and faster turnaround.

Pin registration is used in die cutting to maintain accuracy throughout all

processes. Our die cutting presses are set-up, maintained and operated by

highly skilled people who understand the critical nature of membrane

switch quality.

Assembly

Membrane switch assembly at Bergquist is a function of skilled people and

quality-driven processes. Switch layer assembly is all pin registered for con-

sistent accuracy. The exclusive Bergquist HeatSeal process is equally pre-

cise and consistent.The result is a custom membrane switch that performs

as specified and will stand the test of time.

Options

More Choices Mean
Better Solutions

Bergquist offers a wide range of choices of how your HeatSeal

membrane switches can look, feel and function. This page shows

many of our standard features, available options and an inside look

at what makes a higher quality switch.

Graphic Layer

Materials

•

Polyester – offers long life and chemical resistance; 7 mil std.

•

Polycarbonate – with velvet texture; 7 or 10 mil std.

Hardcoats

•

Gloss, semi-gloss and matte finishes are available

•

Increases chemical and scratch resistance

•

Selectively applied to create display windows and
decorative finishes

Colors

•

Pantone (PMS) or custom matching using a color computer

•

Transparent/translucent colors for back-lighting and windows

•

“Deadfront” available to hide leg ends/windows until back-lit

Embossing

•

Tactile formed graphic over flat circuits
(typically most cost-effective)

•

Pillow embossing – 0.015" typical height; generally used
over polyester domes

•

Rim embossing – 0.010" typ. height; for locating pads by feel

Graphic Adhesive

•

5 mil standard thickness

Switch Circuit Layers (top and bottom)

Switch Types

•

Screened silver circuit – most economical; for switching loads one
watt or less; typical top and bottom layer thickness is 5 mil

•

PC board – copper circuitry for switching loads greater than one
watt or when components (LEDs, displays, etc.) are used

Circuit Types

•

Matrix and short-to-ground are most common

•

Involving us early in the design stage allows us to make suggestions
that help ensure a reliable membrane switch

Polyester Domes

•

Formed into top switch circuit layer of silver circuit switches

•

Formed into shunt/dome cover layer of PC board switches

•

Provides tactile feel and long life; typically 24 – 30 mil height

Shielding

•

Screened silver grid – applied to top side of silver circuit for
ESD protection

•

Aluminum and gold vapor deposition – ESD, EMI and RFI
protection; adds approximately 5 mil to total thickness

Spacer Layer

•

HeatSeal – internally vented preferred for most applications
(PSA available - externally vented)

•

6 – 8 mil thickness typical when using polyester domes

•

6 – 14 mil thickness typical for flat switch

•

Spacer thickness depends on actuation force requirements
back lighting

•

Electroluminescent lamp

•

Fiber-optic

•

LEDs – soldered on PC board switches

PC board components

•

Standard PC board thickness from 0.030" to 0.125"

•

Stainless steel snap domes – used on nickel-plated copper or PC
boards; for tactile feel and temperatures above 150

•

Surface mount and feed-through components

Backers or Enclosures

•

Metal, FR4 or polycarbonate backers

•

Plastic enclosures

Graphic Layer

Graphic Adhesive

Mylar Shunt or
Dome Cover Layer

Stainless Steel Domes

HeatSeal Spacer

Lighting

PC Board, standard
thickness from .030"
to .125"

PC Board HeatSeal Membrane Switch

Resistive Touch System

Innovative, Seamless Membrane Switch/Touch Screen Technology

Introducing a New Standard in Reliability
and Redundancy for Critical Control Applications

As a world leader in both membrane switches and analog resistive

touch screens, it seemed an obvious choice to combine these two

technologies to create the innovative seamless RTS resistive touch

system.This permits the design and manufacture of custom prod-

ucts having the reliability and redundancy required for medical

devices, industrial controls and other critical applications.

Membrane Switch

Bergquist’s proprietary HeatSeal membrane switches are custom engi-

neered for use in environments where reliability is critical. The HeatSeal

process thermally bonds switch layers together, providing a seal that is

impervious to moisture, temperature extremes and cleaning chemicals.

Options include screened silver ink or PC board circuitry, tactile graphics,

rim or pillow embossing, deadfront or translucent windows and more.

Touch Screen

Bergquist’s patented 5-Wire analog resistive touch screens are engineered

for critical applications. Features include drift-free operation, fast speed,

actuation force consistency, industry-leading light transmission and touch-

point density, plus reliability up to 30 million cycles.

RTS Interface

By combining membrane switch and touch screen technology into a sin-

gle RTS unit, devices used in critical applications benefit from unprecedent-

ed reliability and redundancy. The many design options allow engineers

extensive flexibility in the design process. Plus, the seamless top layer elim-

inates all cracks and crevices where build-up can cause contamination and

premature failure.

Since both the membrane switch and touch screen are manufactured in
house, Bergquist customers experience no dispute between vendors over
product quality.

Membrane Switch + Touch Screen = Resistive Touch Systems

Resistive Touch System

Custom Engineered for Your Application

The Bergquist RTS resistive touch system has a seamless one-piece

face that is easily cleaned, with no cracks, crevices or ledges for dirt

and grime to collect. Each custom-engineered RTS unit can employ

the same functional and performance features offered on all

Bergquist HeatSeal membrane switches and 5-Wire resistive

touch screens as shown below.

Graphic Layer

Polyester construction

– offers long life and chemical resistance

Optional hardcoats

•

Gloss, semi-gloss or matte

•

Chemical and scratch resistant

•

Can be used to create display windows and decorative finishes

Custom colors

•

Translucent colors for back-lighting and windows

•

Deadfronts to hide legends until back-lit

Variety of tactile response options

•

Tactile graphic over flat circuits

•

Pillow or rim embossing

•

Polyester or metal domes

Switch Circuit Layers

•

Screened silver circuit – for switching loads up to one watt

•

Copper PCB – for switching loads greater than one watt, or
when using LEDs, displays, etc.

•

Screened silver shield applied to top of circuit for ESD
protection

Spacer Layer

•

HeatSeal – internally vented

•

Thickness based on actuation force requirements

Construction Features

•

Patented design

•

Custom sizes

•

Diagonals as small as 3.8"

•

High-accuracy off-ratio sizes

•

Slim perimeter – drops into most
existing 4-Wire and 8-Wire spaces

•

Variety of glass thicknesses

•

Flexible tail location

•

Custom lengths and terminations

5-Wire Advantages

•

5-Wire resistive analog technology –
superior to 4-Wire, 8-Wire and
resistive matrix technologies

•

Most durable resistive analog –
drift-free operation even when
exposed to temperature fluctuation

•

Increased optical clarity

•

Greater touch point density

•

Increased speed and accuracy

•

Simple 2-point calibration versus up
to 25-points for others

•

No external electronic correction
needed (NovRam)

•

Windows

compatible

Membrane Switch Features

Touch Screen Features

RTS Resistive Touch System

Touch Screen

Assembly

Seamless top layer

Membrane Switch
Assembly

Smooth,
easy-to-clean surface

No dirt build-up

like this:

Bergquist Switches

The Bergquist Company...

was founded in 1964 by Carl Bergquist as a distributor of compo-

nents to electronics products manufacturers. Today, the company

is a recognized authority in the manufacture and distribution of

thermal products, membrane switches, electronic components and

touch screens.

Membrane Switches

Bergquist’s proprietary HeatSeal

membrane switches are custom engi-

neered for use in harsh environments where reliability is critical. The
HeatSeal process thermally bonds switch layers together, providing a seal
that is impervious to moisture, temperature extremes and cleaning chemicals.

Features:

•

HeatSeal, a proprietary adhesive bonding process

•

Up-front problem solving through team management

•

Customer-focused engineering and support

Thermal Products

Bergquist’s Sil-Pad

thermally conductive insulators and Thermal-Clad

insulated metal substrates control and manage heat in electronic assem-
blies and printed circuit boards. Extensive research and development helps
Bergquist meet the critical thermal management needs of the rapidly
changing electronics industry.

Features:

•

Sil-Pad and Gap Pad

, world’s top heat management products

•

Broad range of thermal options from interfacing to adhesives

•

Thermal Clad, recognized leader in dielectric coated material

Electronic Components

Bergquist Electronics is a value-add supplier to OEMs in a wide variety of
industries.The division provides assistance in design, manufacturing, global
sourcing, and logistics.The division also distributes electronic components
in the Midwest United States.

Features:

•

Electronic components to complete engineered solutions

•

Asian and European manufacturing and assembly facilities

•

Customer engineering and strategic support

Touch Screens

Bergquist’s 5-Wire touch screens feature unique construction and electri-
cal functionality, making them extremely durable. 5-Wire touch screens
also feature patented optical technology, providing an enhanced level of
clarity and contrast.

Features:

•

Drift-free operation during temperature changes

•

Ability to withstand 35 million activations in a single touch-point

•

Continued functionality, even with damage to top film

Labels and Graphic Overlays

This division designs and manufactures printed nameplates, graphic over-
lays, pressure sensitive labels, and other products to meet the product
identification and interface needs of a variety of industries. With challeng-
ing application requirements, they offer a full line of U.L. recognized, CSA
and CE materials.

Features:

•

Full line of identity materials from rolls to custom shapes

•

SharpTech

4-color printing technology

•

Broad range of graphic overlays and nameplates

Custom Engineered

Solutions for Harsh

Environment Survivability

Membrane

FEBR

2007

SW-CAT-02-07

DOMESTIC AGENTS

For a complete list of Bergquist sales representatives in the U.S. contact
The Bergquist Company: 1-800-347-4572.

INTERNATIONAL SALES OFFICES

HONG KONG

The Bergquist Company
Asian Headquarters
Room 15, 8/F
Wah Wai Industrial Centre
No. 38-40,
Au Pui Wan Street
Fotan, Shatin, N.T.
Hong Kong
Tel: 852-2690-9296
Fax: 852-2690-2344

THE NETHERLANDS

The Bergquist Company
European Headquarters
Bramenberg 9a
3755 BT Eemnes
The Netherlands
Tel: 31-35-5380684
Fax: 31-35-5380295

CHINA

The Bergquist Company
China
Rm. 7C
Aihe Mansion
No. 629 Ling Ling Road
Shanghai, China 200030
Ph: 86-21-6464-2206
Fax: 86-21-6464-2209

GERMANY

Bergquist ITC GmbH
Haderslebener Str. 19A,
D-25421
Pinneberg
Tel: 49-4101-803-230
Fax: 49-4101-803-100

SOUTH KOREA

The Bergquist Company
Korea, Ltd.
#5303 Dongil Technotown
Anyang 7 Dong
Manan Ku, Anyang Si
Kyunggi Do
South Korea, 430-817
Tel: 82-31-448-0382
Fax: 82-31-448-0383

ENGLAND

Bergquist UK Ltd.
Unit 27 Darin Court
Crownhill Ind. Est.
Milton Keynes MK80AD
Tel: 44-1908-263663
Fax: 44-1908-263773

AUSTRALIA
AUSTRIA
BELGIUM
BRAZIL
CANADA
CHINA
DENMARK
FINLAND
FRANCE

HOLLAND
HONG KONG
ISRAEL
ITALY
JAPAN
MALAYSIA
MEXICO
NEW ZEALAND
NORWAY

PORTUGAL
RUSSIA
SINGAPORE
SPAIN
SWEDEN
SWITZERLAND
TAIWAN
THAILAND
TURKEY

INTERNATIONAL AGENTS

Corporate Headquarters and Sales Office:

18930 West 78th Street

Chanhassen, MN 55317

Toll Free: (800) 347-4572 • Main: (952) 835-2322 • Fax: (952) 835-0430 • www.bergquistcompany.com

Thermal Products •

Membrane Switches

• Touch Screens • Electronics • Labels and Graphic Overlays