• Matrix – a double diamond pattern that works great for gestures
• Discrete – a cost-effective option requiring less production time, they also offer specific touch points that help prevent false touches and are often favored in harsh environments
• Slider – maximizes versatility by allowing the entire X axis to serve as a touch point, while still maintaining a cost-effective approach

• Standard – off-the-shelf, comes in standard sizes (4.3″, 5.0″, 7.0″, 10.4″, etc.)
• Custom – allows for any shape and size required

• Acrylic – a durable polymer material with a scratch-resistant coating and available in standard thicknesses
• Chemically-Strengthened Glass – provides an excellent touch surface and looks great
• Polycarbonate – provides greater impact resistance at the expense of a softer surface that can be scratched more easily

The tail connects the electrodes of the sensor to the inputs of the controller. Off-the-shelf sensors use a bonded tail with fixed length and location, often requiring the electronics to be reconfigured. A custom sensor can place the tail in almost any location on the sensor, in the exact length that best meets the requirements. Moving the tail on the sensor is often much easier than moving electrically noisy components or adding specialized shielding to those components.

The length and location of the tail can make a significant difference in the cost of the overall part, both through material costs and physical dimensions pertaining to the manufacturing configuration. By strategically positioning the tail in the optimal location, more parts can be printed per sheet, thus optimizing the cost and facilitating ideal integration with the circuitry.

There are two main ways to create the tail:

• Integrated Tail – printing conductive traces on the same polyester sheet from which the sensor is made. Think of it like an extension of the sensor itself. Integrated tails provide the most reliable connection to the sensor. Kodak HCF film with PEDOT allows for an extremely tight bend radius for final assembly – meaning the finished assembly is very durable.
• Bonded Tail – made from a different flex circuit and bonded to the sensor. This is the standard configuration for ITO sensors. You typically see the orange colored polyimide tail connected to the transparent sensor using conductive bonding materials to make the electrical connections. Generally more expensive to produce, bonded tails can also include the sensor controller directly on the tail itself (called chipon-flex or COF).

The controller is the brains of the operation. The sensor detects changes in capacitance, and the controller chip is required to interpret those changes. Most standard sensors feature a controller on a flex circuit bonded to the sensor; however, that may not always be the best configuration.

When choosing a controller, be sure to ask:

• Is this the best controller for the application?
• Are the settings in the controller optimal for the application?

In most instances, it is most economical to have the controller be part of the main control board. Placing the controller directly on the tail is only economical when space on the main board is limited.