LCD Touchscreen Technology: Comprehensive Analysis and Selection Guide

1: Capacitive Touchscreen

Capacitive touch technology relies on the mutual induction between human body currents and the ITO conductive layer to function. It typically consists of four layers of glass, with ITO coatings on the inner surface and interlayer, and a protective layer of silica glass on the outermost layer. The interlayer ITO coating serves as the working surface, with electrodes drawn out from the four corners. When there is a touch with the human body, the finger and the working surface form a current, which is detected by the electrodes to determine the coordinates of the touch point. Capacitive touchscreens require only touch, not pressure.

Pros:

• Fewer post-production calibrations, improving efficiency and reducing defective products;
• Long lifespan;
• Better light transmittance and clarity compared to resistive touchscreens;
• Easy to design for large-size LCD displays at a relatively low cost;
• Supports multi-touch technology.

Cons:

• Large-area palm or handheld conductor proximity can cause unintended touch actions;
• Ineffective touch response with gloves or insulating objects;
• Non-uniform light transmittance and color distortion;
• Changes in ambient temperature and humidity can cause touch inaccuracies.

2: Resistive Touchscreen

A resistive touchscreen utilizes pressure sensing for control. It comprises two layers of ITO (Indium Tin Oxide) plastic film (ITO+Glass) coated with conductive function. When pressure is applied, the two layers of ITO make contact to form a current signal, enabling touch processing of the entire screen mechanism.

Pros:

• Mature technology, low cost;
• Good environmental adaptability, unaffected by dust, water vapor, and oil pollution;
• Stable performance, responsive to both human touch and objects;
• High precision, easy to design for large resolution LCD screens.

Cons:

• Susceptible to scratches, rendering touch ineffective;
• Poor light transmission, leading to increased battery consumption;
• Reduced touch sensitivity, especially with multi-touch usage.

3: Infrared  Touchscreen

Infrared touchscreens are easy to install, requiring only the addition of a light spot distance frame on the LCD display panel, without the need for any IoT coatings. They utilize a dense infrared matrix in the X and Y directions to detect and locate touch points.

Pros:

• Unaffected by current, voltage, and static electricity;
• Low cost, easy installation without the need for any controller;
• Compatible with computers of various grades.

Cons:

• Challenging to use on large-sized LCD screens;
• Susceptible to external light interference;
• Not waterproof or oil-proof, prone to errors from small foreign objects.

4. Surface Acoustic Wave Touchscreen

Surface Acoustic Wave Touchscreens utilize a glass plate installed on the surface of the display, with vertical and horizontal ultrasonic senders and receivers. When a finger touches the glass surface, it absorbs part of the sound wave energy, enabling the controller to determine the position of the touch point.

Pros:

• High clarity and good light transmittance;
• Highly durable, with good scratch resistance and responsiveness;
• Not affected by environmental factors such as temperature and humidity, with high resolution and longevity;
• High light transmittance, maintaining clear and bright image quality.

Cons:

• Applicable to smaller screens, challenging to use on larger screens exceeding 30 inches;
• Susceptible to moisture damage, unsuitable for many industrial and commercial applications;
• Dirty surfaces can cause dark spots on the screen, requiring regular cleaning.