If you’re wondering whether a TFT LCD display module is the right choice for your application or not, then you’re in the right place. We prepared a detailed guide to help you make the smartest choice for your business. The guide will help you in better understanding the choices you have in subassemblies of a TFT display module.
Read on to find out everything you need to know about TFT display modules before approaching a manufacturer.
Let’s start with the basics. What does TFT LCD actually mean? TFT stands for “Thin-Film Transistor” and LCD stands for “Liquid Crystal Display.” When put together, a TFT LCD display is a flat-panel display or screen that you may find in computer monitors, TV sets, and mobile devices like smartphones and tablets.
TFT displays are made of large sheets of transistors, where each transistor of which is controlled independently. In its essence, a TFT screen is an active-matrix screen – each pixel on display is illuminated individually.
The first layer we’re going to examine is the cover glass in its rigid variant. Most of the time, clients choose chemically strengthened glass or Gorilla Glass™ in different impact-resisting thicknesses. The cover glass may come with a gloss or matte anti-reflective finish. Adding static backlit images is an option as well. The cover glass may also have mechanical buttons – fixed capacitive or through-hole mechanical ones.
Let’s dive into the details:
Final notes: Glass strength is mostly related to the question of equilibrium. As the market requires thinner and stronger glass options, the manufacturers of protective glass strive to innovate and develop new glass technologies. It’s also likely that the demand for flexible protection choices grows in the future.
If you’re looking to develop a TFT LCD resistive touch screen that responds to touch pressure, you need a cover glass that is flexible. To accomplish that, the manufacturer may use the same material as the top layer of a membrane switch – a resistive touch screen can include membrane switch functions.
How does this glass layer work in a resistive touch screen? A resistive touch screen is an overlay that uses physical pressure to detect any touch input. This type of touch screen consists of two layers – a flexible outer layer and a glass inner layer. These two layers are separated by an air gap maintained by microdots. This layer configuration can process only single touch events, reducing the transmittance (brightness) of the display underneath by 20% to 30%.
PCAP screens
The capacitive touch screen (PCAP) was invented many years before resistive touch screens, but they have become more popular recently with the rise of consumer electronics products like smartphones and tablets.
PCAP touch screens offer high sensitivity and respond immediately to touch input. These screens are made of transparent and conductive materials such as ITO that are coated onto the glass material.
Contrary to the resistive touch screen we mentioned in the previous point, PCAP screens don’t rely on mechanical pressure. Instead, they take advantage of the electroconductivity of the human body (which is naturally conductive). This is why PCAP screens work only with exposed human fingers or special styluses.
Resistive touch screens
As we mentioned in the preceding section, a resistive touch screen includes a glass panel and a film screen. Both are covered with a thin metallic layer, which is separated by a small gap. When the user touches the screen and applies pressure, the two metallic layers meet and create an electrical flow. This change in voltage detects the point of contact, converting the voltages into X and Y coordinates that are later sent to the controller.
Final notes: It’s important that you select a touch sensor appropriate that matches the requirements of your application – for example, exposure to moisture and humidity or use of gloved hands.
Thanks to their durability, resistive touch screens find broad use in manufacturing, ATMs, and kiosks, or medical devices. Since in many industries, users need to wear gloves when using touch screens, the resistive screen is a good solution since it doesn’t require contact with exposed human skin or a stylus with capacitive capabilities.
However, thanks to advancements in this technology, PCAP screens are replacing resistive solutions thanks to greater capabilities in handling moisture or gloved hand usage.
When it comes to the TFT display itself, you can choose from two technologies: TFT IPS and TFT TN.
In general, many businesses choose IPS and consider it better than the traditional TFT TN display – especially when it comes to the viewing angle and color conversion. IPS offers higher contrast but also consumes slightly more power. This technology is also more costly – an IPS display costs around 30-50% more than a standard TFT TN screen.
TFT IPS display
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Cons:
TFT NT display
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Stay tuned for the next part of this series, where we continue to explain all the different subassemblies that are part of TFT display modules.
And if you need expert advice, please get in touch with our consultants. At Melrose Systems, we have the know-how and expertise you need to make the best decisions for your application.
If you have any questions on tft lcd modules. We will give the professional answers to your questions.