In the 1970s, the US military first applied touch panel technology for military use. Subsequently, this technology gradually transitioned to civilian applications. With the development of network technology and the widespread use of the internet, a new generation of touch technologies and products emerged, gaining widespread acceptance for their durability, fast response speed, space-saving design, and ease of communication. Currently, this most convenient human-computer interaction technology has been applied to numerous fields. Besides personal portable information products (such as PCs, PDAs, and AVs using handwriting input), its applications extend to information appliances, public information (such as e-government, banking, hospital, and power sector business inquiries), video games, communication equipment, office automation equipment, information collection equipment, and industrial equipment. Although touch panel technology has only been used in my country for a little over a decade, it has already become the most widely accepted computer input method for ordinary people after keyboards, mice, handwriting tablets, and voice input. Using this technology, users can operate the computer simply by lightly touching the icons or text on the screen, making human-computer interaction more direct and convenient. This technology greatly facilitates users and is very suitable for multimedia information retrieval. Meanwhile, this human-computer interaction method gives multimedia a brand-new look, making it a highly attractive new multimedia interactive device. 1. Basic Principles of Touchscreens The essence of a touchscreen is a sensor, consisting of a touch detection component and a touchscreen controller. The touch detection component is installed in front of the display screen to detect the user's touch position and send the information to the touchscreen controller. The main function of the touchscreen controller is to receive touch information from the touch point detection device, convert it into touch point coordinates and send them to the CPU, and also receive and execute commands from the CPU. Currently, based on the type of sensor, touchscreens are roughly divided into four types: infrared, resistive, surface acoustic wave, and capacitive touchscreens. (1) Infrared Touchscreens Infrared touchscreens have a circuit board frame installed in front of the display. The circuit board has infrared emitters and receivers arranged on the four sides of the screen, forming a horizontal and vertical infrared matrix. When a user touches the screen, their finger blocks the horizontal and vertical infrared rays passing through that position, thus allowing the user to determine the position of the touch point on the screen. Any touchable object can change the infrared rays at the touch point to achieve touchscreen operation. Infrared touchscreens are not affected by current, voltage, or electrostatic interference, making them suitable for certain harsh environmental conditions. Its main advantages are low price, easy installation, no need for cards or other controllers, and applicability to computers of all levels. (2) Resistive Touchscreen The main part of a resistive touchscreen is a resistive film screen that fits perfectly with the display surface. Two layers of OTI transparent metal oxide conductive layers are coated on the tempered glass surface. Control is achieved using pressure sensing. When a finger touches the screen, the two conductive layers make contact at the touch point, and the resistance changes. Signals are generated in both the X and Y directions and then transmitted to the touchscreen controller. The controller detects this contact and calculates the (X, Y) position, then operates in a manner similar to a mouse. Resistive touchscreens are not affected by dust, water, or dirt and can work in harsh environments. However, because the outer layer of the composite film is made of plastic, its explosion resistance is poor, and its service life is somewhat affected. (3) Surface Acoustic Wave Touchscreen Surface acoustic waves are mechanical waves that propagate along the surface of a medium. This type of touchscreen is equipped with ultrasonic transducers at the corners. It can send a high-frequency sound wave across the screen surface. When a finger touches the screen, the sound wave at the touch point is blocked, thereby determining the coordinate position. Surface acoustic wave (SAW) touchscreens are unaffected by environmental factors such as temperature and humidity, have extremely high resolution, excellent scratch resistance, long lifespan, and high light transmittance, maintaining clear and bright image quality, making them ideal for public places. However, dust, water, and dirt can severely affect their performance, requiring frequent maintenance to keep the screen surface clean. (4) Capacitive touchscreens work by sensing the electrical current of the human body. A layer of transparent special conductive metal is attached to the glass surface. When a conductive object touches it, it changes the capacitance of the contact point, thus detecting the touch location. However, there is no response when touched with a gloved hand or a non-conductive object, because a more insulating medium is added. Capacitive touchscreens can effectively sense light and rapid touches, are scratch-resistant, and are unaffected by dust, water, and dirt, making them suitable for use in harsh environments. However, because the capacitance changes with temperature, humidity, or environmental electric field, its stability is poor, resolution is low, and it is prone to drift. The performance comparison of the above four types of touchscreens is as follows: Source: Zhang Xuefeng (Reference 3, 2004). 2. Applications of Touchscreens As mentioned earlier, touchscreens have seen rapid development recently. Touchscreen multimedia presentation systems, with their vibrant colors, rich multimedia presentations, and user-friendly operation, provide comprehensive functions such as image display, business consultation, and information inquiry. Currently, touchscreens are widely used in various fields. Here are a few major application areas: ⑴ Store Payment Systems: Some modern stores use computer interactive terminals at their checkout counters. Customers can print payment slips with the names and prices of goods by operating the touchscreen. Merchants can use full-screen video images for product promotion on the terminal, while customers can also inquire about products according to their needs. ⑵ Admission Ticket Inquiry and Reservation Systems: Touchscreen admission ticket inquiry and reservation systems can display reserved seats and viewing conditions at those seats on the screen. After confirming the seats, customers can complete the reservation process by inserting their credit cards into the system. ⑶ Video and Music Players: Video and music players store multiple songs with visuals, multiple video music tracks, and karaoke songs. These can be selected via the touchscreen. Some video and music on-demand machines also offer optional game software. These lively and interesting games can be played simply by touching the screen. For example, Chengdu Jirui Touchscreen Computer Co., Ltd., a company in my country specializing in the research, development, production, sales, and service of touchscreen products, has its touchscreens widely used in the horse racing, gambling, and game console industries in Europe, America, and South Korea. (4) Financial Transactions: In financial transactions, speed and accuracy are two extremely important factors. The use of touchscreens provides users with an easy and rapid means to process rapidly changing information. Users can make judgments based on the displayed content and then complete the decision by touching the screen, thus allowing users to concentrate on the transaction. (5) Public Information Inquiry Services: This application is the most common. For example, a) Real Estate Inquiry and Sales: The online real estate information network designed by ERA in the United States provides various real estate information to users through touchscreen information kiosks set up in public places. This saves homebuyers the trouble of running around and also provides real estate owners with the opportunity to advertise nationwide. b) Postal and Telecommunications Inquiry and Telephone Bill Inquiry: Post offices and telephone bureaus also use touchscreen systems to provide the public with various inquiries, including postal service inquiries, telecommunications service inquiries, postal code and long-distance telephone area code inquiries, and savings and remittance inquiries. For example, the Beijing South District Post Office uses touchscreen inquiry kiosks from Huanxing Company to serve the public. c) Ticketing and Shipping Services: For example, the touchscreen ticket kiosks in the Beijing Railway Station ticket hall allow users to select train numbers, carriage types, number of tickets, destinations, fares, and inquire about other related matters; the stand-up touchscreens at Tokyo Narita Airport in Japan allow passengers to view flight numbers, departure and arrival times, etc. ⑹ Application of Touchscreens in Libraries: With the development and application of multimedia technology, a multimedia retrieval system called hypertext retrieval has been developed and applied. This hypertext stores basic information units such as words, sentences, chapters, documents, and even images, music, and videos on nodes, and the endpoints are connected by active chains such as hierarchical chains, cross-reference chains, and index chains to form a network hierarchical structure. Hypertext software systems include text editing, graphic editing, database management, 3D viewing tools and mapping displays, mouse windows, icons, and pop-up menus, among other standard hypertext tools. Their characteristics include associative, non-linear, chain-like hierarchical connections, allowing users to link information in a meaningful way and quickly retrieve the information they need. In the field of library retrieval, with its extensive collections and rich multimedia resources, this system can be used to retrieve various information such as people, news, documents, novels, prints, calligraphy, paintings, biology, and paleontology. Readers unfamiliar with keyboard operation can use the touchscreen to intuitively and quickly access the multimedia search platform; they only need to touch the relevant content on the touchscreen to immediately view the documents they need. 3. Development Trends of Touchscreen Technology Touchscreen technology facilitates the use of computers and is a highly promising interactive input technology. Countries worldwide have generally attached great importance to it and invested significant human and material resources in its research and development, resulting in the continuous emergence of new types of touchscreens. Stylus: Touchscreens operated with a stylus are similar to whiteboards. In addition to displaying interfaces, windows, and icons, they also have the function of signing and marking with a stylus, and the system has achieved automatic recognition. This stylus is a significant improvement over the earlier light pens that only offered menu selection. Touchpad: The touchpad uses pressure-sensitive capacitive touch technology, boasting the largest screen area at 3m x 4m, making it a wall-mounted system. The touchpad consists of three parts: the bottom layer is a central sensor that monitors whether the touchpad is being touched and processes the information; the middle layer provides interactive graphics and text; and the outermost layer is the touch surface, made of high-strength plastic. When a finger touches the outer surface, the information is sent to the sensor and processed within a millisecond. The touchpad is PC compatible and features high brightness, clear images, and ease of interaction, making it ideal for point-and-click information retrieval systems (such as electronic bulletin boards) with excellent results. In summary, the development of touchscreens shows trends towards specialization, multimedia capabilities, three-dimensionality, and larger screen sizes. It is foreseeable that with the rapid development of touchscreen technology, touchscreens will play a crucial role in the widespread use of computer technology.