DR .chiba: Welcome to the Touch Screen Museum. I am Masao Chiba, a manager of the museum. This museum was established to introduce brief ideas of touch screens, their structures, how they work, and where they are used.
Taro: Nice to meet you, Dr. Chiba. I am Taro Shinagawa. I came here to learn about touch screens.
DR .chiba: Nice to meet you, Taro. I hope you will enjoy the museum.
DR .chiba: Do you know what a touch screens is? It is a human machine interface (HMI). HMI, as its name indicates, is an interface or device that allows communication between machine and its user.
Taro: Can you give me examples of HMI?
DR .chiba: There are various types of HMI around us. Push button is one of the simplest types of HMI. You see them on a TV remote control, on telephone set, in an elevator, and many other locations. Mouse and keyboard are more advanced types of HMI than push buttons. These types of HMI are used to interact with electronic devices with images. When a user operates a personal computer, he moves image of the cursor in the screen with mouse, and input images of characters with keyboard. A touch screen is also this type of HMI that uses images for communications between a user and electronic device. Unlike mouse and keyboard, touch screen allows a user to interact with electronic device by directly touching images displayed on the screen.
Taro: OK, I think I grasped the idea of HMI and touch screen. I have a smartphone that I operate with my fingers. As I touch its display, the images on the display change. It is a touch screen, isn't it?
DR .chiba: Yes, exactly. But, touch screen itself is just a transparent switch that detects touched locations. How the device reacts to your touches is controlled by software. Various input devices can be made with combination use of touch screen, display and software.
Taro: What kind of input devices can be made with touch screen? Can you give me an example?
DR .chiba: OK. For instance, a touch screen can work as a simple push button. Image of a button switch can be displayed on screen, and the device will be programmed to be on and off upon a touch on the image. If number of the button images increase, a touch screen can be used like a keyboard. Since a touch screen can detect coordinate points, it can also function as a mouse (although it does not distinguish between right and left clicks like a mouse).
Taro: I see, a touch screen can perform the same functions as other types of HMI like push button, mouse and keyboard. But, then do we need a touch screen if it performs just the same functions as other HMI? Is there any advantage to choose a touch screen over other HMI?
DR .chiba: I will not be saying that a touch screen is better than other HMI in every aspect, but it surely has many advantageous aspects that no other HMI can replace it. The advantages and drawbacks of touch screen will be introduced here.
DR .chiba: Can you name any touch screen product in your life?
Taro: I have some touch screen devices such as smartphone, camcorder, tablet computer and so on. I also see touch screens in a car, automotive navigation device.
DR .chiba: As you see, a touch screen has been familiar to us today, as mobile devices such as smartphones achieved popularity. However, touch screens have been used in many occasions well before these mobile devices appeared. Its intuitive operation is useful to users, and its high degree of freedom in design is advantageous for device makers. These factors back up the broad use of touch screens today. The technology advancement of touch screens has been remarkable. It has been keeping expanding its application areas. Below are just some examples of touch screens around us. (chart of Touch screens around us)
Touch screens around us
- In-flight Entertainment
- Handheld Game Console
- Tablet PC
- Fitness machine
- Automotive navigation
- Network Terminal
- Ticketing Machine
- Sewing Machine
- Order Terminal
- In a Ship
- Factory Automation
- Medical Equipment
- Office Automation
- Arcade Game
- Interactive White Board
- Digital Signage
- Large-size Monitor
Taro: How does touch screen detect touched locations?
DR .chiba: There is a variety of touch screen technologies, and each technology has a unique detecting method. Electricity, light, or sound is usually used for detection, according to the technology.
Taro: Which technology should be employed?
DR .chiba: Each technology has its unique feature. Thus which technology to be used depends on applications. Thus, buyers of touch screens usually consult with a touch screen supplier about it. The most common technologies are introduced in this museum. They are resistive, capacitive,surface acoustic wave, and infrared technologies. (chart of Technologies)
- Resistive Technology
- Capacitive Technology
- Surface Acoustic Wave
- Infrared technology