This blog post explains the flow and principles of technological development, from the birth of television to the latest smart TVs.
Television (TV), one of the main electronic devices in our homes, is a telecommunication method that sends the optical image of an object over the airwaves and reproduces it on a receiving device, or a receiver that receives the image. Television is a combination of the words “tele,” which is Greek for “far,” and “vision,” which is Latin for “see.” The principle of this technology is to convert the video sent from the broadcasting station into radio waves, receive it through an antenna in the air, and then convert the video again to make it visible to our eyes. The introduction of television brought about a major innovation in home life at the time and caused a fundamental change in the way people consume information.
Television has evolved in various ways depending on the method of implementing radio waves on the television screen. Starting with black-and-white television in the early 1950s and 1970s, it has continued with color television (CRT) in the 1980s, and then with LCD, LED, and PDP televisions since the 1990s, with the quality and functions of the image greatly improved with technological advancements. The development of television began in earnest when German physicist Karl Ferdinand Braun (1850-1918) developed the cathode ray tube (CRT), commonly known as the “ブラウン管” (Braun tube). The cathode ray tube uses the principle that light is emitted when fluorescent material is hit by a cathode electron fired from an electron gun and deflected by a coil, which utilizes a characteristic of visual perception, just like a film.
The ‘flip book’ is also based on this principle. Simply put, if you quickly flip the pages with your thumb, the illustrations will look like a moving image. This phenomenon was thought to be due to the images remaining on the retina for a long time, but in fact, it is caused by the stimulation of certain parts of the retina that are specialized for detecting movement. As the Lumière brothers, who first created a movie in 1895, understood, a series of images gives the impression of movement. The principle of continuous images on television is similar.
The principle of color television is also based on a cathode ray tube, just like black-and-white television, but the difference starts with the way our eyes perceive color. Our retinas analyze color through receptors called cones, and these cones are sensitive to three colors: red, green, and blue. Mixing these three colors produces a wide range of colors, and the colors on a television screen are based on this principle. The screen of a television receiver is made up of hundreds of thousands of pixels, each of which consists of three subpixels that emit red, green, and blue light. This allows all colors to be reproduced, and as a result, our eyes perceive a wide range of colors.
As the size of a CRT television increases, the space it takes up front and back increases dramatically, and the production cost increases significantly. Therefore, flat-panel display televisions such as LCD, LED, and PDP televisions began to be commercialized in the 2000s. LCD (Liquid Crystal Display) televisions operate in a similar way to the liquid crystal devices used in portable electronic watches and wristwatches. This technology uses liquid crystal particles that reflect light in response to electrical signals to form the screen, and the screen is illuminated by the backlight behind the panel.
LED (Light Emitting Diode) televisions are similar to LCD televisions, but they use light-emitting diodes as the backlight. This technology boasts high efficiency with low power consumption, but it is somewhat expensive and, like LCDs, can cause screen drag. OLED (Organic Light Emitting Diodes) televisions are differentiated from LEDs by using self-luminous organic materials, which eliminates the need for backlighting. This allows for a thinner and lighter design and lower power consumption. However, there are limitations to commercialization due to the difficulty of scaling up and the problem of lifespan.
PDP (Plasma Display Panel) televisions display the screen using the principle of gas discharge using plasma gas. This method is excellent in terms of reaction speed, viewing angle, and color, but it has the disadvantage of being heavy and consuming a lot of power. In addition, there are limitations in terms of efficiency because heat is generated by gas discharge.
The development of television is not limited to changes in screen technology. It has also expanded its functionality, such as linking with smartphones and integrating with the Internet. In particular, smart TVs, which have appeared since the 2010s, have gone beyond simple broadcasting reception and now provide various functions such as Internet search and app launch, playing an important role in the smart home environment. Televisions are now becoming more than just a device for watching TV, but are becoming the main media hub in the home, providing a variety of entertainment such as live streaming, video calls, and online games through an internet connection.
The television of the future is expected to go beyond simply improving current functions and will transform the user experience even further by combining artificial intelligence (AI) and the Internet of Things (IoT). For example, AI-based personalized content recommendation features and voice recognition-based control systems will make using the television more convenient and smarter. In addition, the introduction of hologram technology will enable a more immersive viewing experience, and through this, the television will evolve from a simple video playback device to a window that breaks down the boundaries between reality and virtual reality.
