It should come as no surprise that here at Sensigraphics, we are big fans of the membrane switch. Its diverse application potential and myriad of advantages make it an ideal solution for many interface applications. We recently came upon an article, featured below, from our friends at Membraneswitchnews.com that we felt was a perfect real world example that highlights some of the practical benefits of a membrane switch.

“Understanding the Value of a Membrane Switch”

membraneswitchnews.com

If you’re having trouble understanding how and why membrane switches are useful and important tools, consider this situation. You and a few friends have gathered in your living room to watch a game on TV. The gathering involves a lot of food and drinks, which, combined with spontaneous outbursts in reaction to the game, is a recipe for disaster. One of your friends, whose personality is characterized by a combination of hyper excitability and limited spatial awareness, inadvertently knocks a plate of sticky snacks over onto your remote, which is on the floor. There are two ways that this story could end.

Here’s the first way. If your remote is composed of a plastic shell and several individual buttons, you have at best a protracted and annoying cleaning effort ahead of you. At worst, the snack could get plugged in between the buttons and maybe even ruin the device. This situation is not far fetched, and it can be extrapolated to scenarios involving other electronic devices that can be ruined by spills, such as phones, PDAs and other electronics.

Here’s the second way the story could end. If your remote is composed of a plastic shell with a single switch membrane, you can simply wipe off the surface and resume watching the game. Membrane switches are composed of several layers of membranes that allow users to interact with the devices’ circuitry without the possibility of contaminating it. These devices are prized also because they can, in certain configurations, resist hazardous climatic conditions like moisture or dust accumulation, which means that some membrane switches are suitable for use outdoors. Imagine the implications for industry, where hazardous materials can frequently be in use. They also involve fewer moving parts than other kinds of keypads and switches, which means that they feature fewer things that can go wrong. For these reasons, membrane switches are very popular and important utilities.

If you knew that a certain type of minor change in your product could benefit your customers, improve the touch and feel, and help strengthen user feedback in the field, wouldn’t you want to get started?

Well, it has been proven that tactile feel and feedback can do all of that and more. Tactile response is not just about placing a dome in the membrane layers and getting a snap. There are different ways of the designing the membrane switch that affect the tactile feel. When the metal dome is actuated in a Sensigraphics designed switch you have that crisp tactile feel that will benefit your products.  

1-What is behind the membrane switch?

Before we even get into the membrane switch, I always ask a customer what is behind the membrane switch. This helps determine if the force behind the dome being actuated is a strong contact point for the snap back of the dome. Whether you are using a metal or polyester dome, you begin to lose a large percentage of your tactile response when the backer is not firm enough. It is suggested that a very firm backer of some type of metal or ABS plastic backer is behind the membrane switch. For example if you actuate a dome on flexible backer the deflection compromises and absorbs the snap back force,  but when actuated on a metal or ABS plastic backer, there is little to no snap back force  being absorbed. “One of the best ways to improve tactile response in a membrane switch is to add strength to the backing of the domes,” advises Bill Morris, Vice President and Chief Engineer of Sensigraphics.

2-What kind of Dome to use?

Domes have their own unique strengths and differences. Most of these differences have to do with the actuated tactile feel of the dome. The best size to use in most cases is a square 12mm 340 gram dome. It’s about the size of the tip of the finger and the trip force combination that is not too soft and not too strong. There are two types of Snaptron standard square domes, the F-series and U-series. The F series is the standard dome and the U series has the ultra snap. The U-series is ideal for anyone who wants a little bit more actuation response than the standard F-series. The domes can be seen at http://www.snaptron.com/domesdomesstanuserzxqL3157.cfm.

3-How many layers are between the dome and the force?

When you begin adding multiple options for your membrane switch they will make your product stand out. However a drawback to this is adding multiple layers and receiving a lower tactile ratio. The risk of the dome being actuated by indirect pressure is also increased. To solve the problem of maintaining your membrane options without sacrificing tactile feedback, a thin polyester or polycarbonate layer can be added with a small-debossed bump directly above the middle of the dome. This extra expense is worth the peace of mind.

Happy Holidays from all of us at Sensigraphics with our best wishes for a happy, healthy and prosperous 2012.

Whether it’s resistive, capacitive, surface acoustic wave or the new technology that is on such hot products like the iPhone, the iPad, or Android products, which use projected capacitive touch screen technology in various forms, everyone simply must have touch screen technology on their latest interactive device.

Here are some of the technologies available and their advantages:

Projected Capacitive technology allows for multiple zones of touch to occur. This can be accomplished due to an invisible grid of sensors on the back of the substrate that map the location of all fingers that come in contact with the screen. The grid pattern detects location of touch by determining relative levels of current within the matrix.

Surface Acoustic Wave technology is the next most advanced technology and is best suited for kiosks and Point of Purchase displays. It relies on piezoelectric transmitters and receivers arrayed along the edges of the touch screen. They transmit and receive signals at once, by converting the signal into ultrasonic waves. When you touch the screen, the waves fan out, are absorbed by the array of traces around the perimeter of the screen, and a touch event is directed to the point.

Advantages:

• Most widely used touch technology
• Activation by finger, soft conductive stylus or some gloves
• Low Cost and wide range of sizes

Resistive technology offers the durability that – for example – a field tester will need when using an instrument to detect leaks. Much like membrane switches, many of the same ruggedized materials are used in their construction. They hold up well to temperatures between -10º and 60º C. Due to the ITO shield, these touch screens are resistant to shorting or interference as well as chemicals. The screen, while appearing solid, is actually a thin shield with a space between it and the glass. When this durable and conductive ITO shield comes in contact with the glass, the location is noted and a command is executed.

5-Wire Resistive touch screens interact with some form of microprocessor, LCD controller and a graphics chip which renders images on the screen. 5-wire resistive touch screens render the images to the LCD allowing the processor to work harder processing information, especially for hi-use rugged applications. This is because they have a glass substrate suited for more extreme temperatures. Light screens can be added for outdoor usage. LED back lighting is often used to increase contrast and brighten the graphics.

Advantages:

• Most widely used touch technology
• Activation by finger, stylus pen or gloved hand
• Low Cost and wide range of sizes

Surface Capacitive touch screens generally are composed of a scratch resistant top layer, an insulator around the perimeter, a clear anti-glare hard coated layer, then the electrical traces that exit as a connection tail, under this array of traces is the conductive coating, and finally the glass. We choose to reinforce the tail at the conjunction of the traces before their parallel path down the tail. The tail is fitted with a connector each specific controller.

Advantages:

• Withstands contaminants and liquids
• Very light force by finger or tethered pen for activation
• Extremely fast response to touch time

Touch screens are rapidly becoming the interface solution of choice in medical technology, military applications, testing and detection equipment, retail banking, transportation, and the entertainment and gaming industry, just to name a few.

Touch screens are part of our daily lives as we make transactions, buy groceries and home improvement products, or travel to our next destination. They continue to be the next destination for designers who develop new products around the world. Sensigraphics is proud to be a part of this growing world-wide creative technology for a new generation of designers.

For more information reference our touch screen product page.

Welcome to the first edition of Touch Points, the new Senisgraphics blog on the latest developments in the industry. Although we have been around since 1994, our latest year has been our most eventful. Our new blog is small part of the overhaul of our company and is part of our commitment to provide leading industry ideas and information.  Our new logo, web site, blog and new facility are all part of the “new” Sensigraphics story, positioning our company for the future. Yet, we still maintain the same dedication to customer satisfaction by hand selecting our customer base and providing top notch design, engineering, and prototyping services.

As you may know, Sensigraphics is an industry-leading manufacture/supplier of custom of membrane switches, graphic overlays, control panels, and touch screens.  Sensigraphics is the most dependable partner for manufacturing user interface components and utilizes the most state of the art manufacturing techniques and equipment.  We moved earlier this year to our Mount Laurel, NJ facility to specifically encompass a one piece flow system using lean manufacturing principles and are convienently located with Productive Plastics, a custom plastics thermoformer. In addition Productive Industrial Finishing, a custom industrial finishing and powder coating facility is also located nearby.

At Sensigraphics our custom capabilities and core competences are broad and include:

• Membrane Switch Assemblies
• Graphic Overlays
• Elastomer Keypads
• Control Panel Assemblies
• Touch Screen Assemblies
• Graphic labels/overlays
• PCB Based Switch Assemblies
• Prototyping
• Design and Engineering

Lots of changes here at Sensigraphics, but our commitment to providing the highest quality products and service remains unchanged.

We will enjoy sharing our thoughts and ideas via Touch Points. But more importantly, we seek your feedback. We look forward to hearing from you.