As the ITO layers of the top and bottom sheets contact, electricity gets conducted at the contacted point, and the location of the conducted point is detected. I see. So, we press the top sheet and make it physically contact the bottom sheet.
The contacted point of the top and bottom sheet is detected. What material is used on base materials of top and bottom sheets? I think the material of the top sheet must be flexible, because it needs to yield when pressed. PET film, glass or polycarbonate plastic is most commonly used.
Each combination has its distinctive features. In the video below, Tom Poplawski and Will Hoffarth demonstrate how capacitive and resistive touchscreens work. There are two types of capacitive touchscreens: projected capacitive and surface capacitive.
The two work similarly and as a user, it is difficult to differentiate between them. Projected capacitive is the more common type of touchscreen and it is what Teguar uses on many industrial and medical computers and tablets.
Projected Capacitive PCap touchscreens are used on the vast majority of smartphones and tablets. PCap screens consist of a layer of glass, a matrix of electrodes and a protective film. When you tap the surface of a resistive touchscreen, the two layers make contact — and this is how resistive touchscreens are able to identify where, exactly, you touched. The two layers of a resistive touchscreen contain electrodes. There are different configurations for these electrodes, some of which include matrix and analog.
In a matrix configuration, the electrodes are arranged in a striped formation on opposite sides of the layers. Since the top layer is acting only as a probe it will still function if the top surface becomes scratched or torn unlike the 4-wire making it a more durable design. The last type is the 8-wire and this is based on the 4-wire technology principle by adding an additional 4-wire set. Having the additional set doubles the level of electrodes and in turn will increase the overall accuracy and reduces drifts so you won't have to recalibrate as much as you would with a 4 or 5 wire touch panel.
The general benefits of resistive touch panels include lowest costs in comparison to other types of touch panels. Additionally they offer low power consumption and are pressure actuated with a finger, gloves, stylus etc. RTPs are also resistant to external factors such as water and dust so if the end product were to be used in an outdoor application or in a machine shop it won't create a false actuation.
Here are some limitations to consider when deciding whether or not RTPs are suitable for your application. You may be more familiar with multi-touch panels but the standard for resistive touch panels is one-touch. There are some controller companies working on multi-touch technology with resistive touch panels but again, it's not the standard.
The touch life is lower for resistive touch panels because they use ITO film as the conductive material which is less durable than other options. Repeated pushing and selecting over time will create fractures and can degrade the touch panels' ability to operate. With a 4-wire and 8-wire expect 1 million actuations in one location because they both share the same technology. The 5-wire will allow 10 million actuations. The standard sizes for all range from 2. Another type of touch panel, are the infrared touch panels ITPs.
Infrared technology consists of infrared LEDs Light emitting diode and light sensors that are placed on the perimeter of the bezel. LEDs transmit beams of light that run parallel to the assigned light sensor create a light grid. Anything that disrupts the light or reduces the light such as a finger or stylus will register a touch See Figure 2 ; the controller will distinguish where contact was made. Figure 2: Contact and disrupted light to Infrared Touch Panel.
The benefits that come with using infrared touch panels start with the size. This technology works best with larger screens. Standard sizes are between 15"- 46" with options for custom sizes. Infrared touch panels are capable of multi-touch with two contact points which will work with any opaque object. There is no flexing of layers like that within the resistive panels so the durability and touch life is a lot higher. The light transmission is greater without the need of a glass substrate.
Since there isn't a need for an extra layer of film or glass over the top of the application the light opacity won't be affected as much.
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