LED and LCD screens invented
LED (Light Emitting Diode) and LCD (Liquid Crystal Display) screens are two pivotal technologies that have transformed visual displays since their invention. The first visible-spectrum LED was created in 1962 by Nick Holonyak, Jr., leading to their use in small displays for calculators and watches by the early 1970s. Initial LED displays primarily emitted a deep red color and utilized magnifying lenses for visibility. In contrast, LCD technology emerged in the late 1960s, featuring a liquid solution that changes color when a voltage is applied, which allowed for lower power consumption compared to LEDs. By the mid-1970s, LCDs gained prominence, especially in calculators and watches, as they evolved to include features like protective filters against UV light.
The development of these screens had a significant impact on various consumer electronics, paving the way for digital quartz watches and compact calculators that utilized minimal power. The 1970s marked a shift from traditional cathode ray tubes (CRTs) to these more efficient screen technologies, leading to widespread applications across devices, including mobile phones, portable TVs, and laptops. Today, the combination of LCDs and LEDs continues to advance, expanding their use in a diverse range of modern electronic displays.
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LED and LCD screens invented
Electronic devices that can project data and images onto a screen
The development of screen displays using light-emitting diodes (LEDs) and liquid crystal displays (LCDs) in the 1970’s led to myriad applications ranging from digital watches to jumbo televisions.
An LED screen is a semiconducting material that emits light when electrical current flows through it in one direction. The color of the light depends on what semiconducting material is used. The first visible-spectrum LED was invented in 1962 by Nick Holonyak, Jr. By the early 1970’s, LEDs were being manufactured by General Electric and Motorola for calculator and watch displays. Most LED displays of that time were very small, requiring that a bubble magnifying lens be mounted above each displayed digit to enlarge the numerals for viewing. During the early to mid-1970’s, most watch and calculator displays in the United States were using gallium arsenide LEDs, which produced a deep-red color. By 1973, the Soviets had developed silicon carbide LEDs, which emitted a greenish-yellow color. By the later 1970’s, LED displays were being used in electronic games, such as Mattel’s Missile Attack and Baseball.
An LCD screen consists of a layer of voltage-sensitive liquid solution that is encased between two sheets of polarizing material. When a small voltage is applied, the liquid changes color. The first operational LCDs were developed in the late 1960’s. In 1971 and 1972, Rockwell, Sharp, and Texas Instruments released some bulky portable calculators with LCD displays that were lit from behind. For pocket-sized calculators that were rapidly being developed during the early to mid-1970’s, LED displays were utilized. However, since LCDs consumed less power than LEDs, LCD development was pursued. Between 1976 and 1977, LCD technology advanced to the point that LCDs became the choice for calculator and watch displays. The first LCD pocket calculator displays used a yellow filter to protect the display surface, which was sensitive to ultraviolet (UV) light. Most used one or two replaceable miniature batteries for power. By 1979, the UV problem was solved, yielding LCD calculators with gray-colored display surfaces. That same year, Milton Bradley released the first handheld game system with interchangeable cartridges, Microvision, which used a monochrome LCD screen.
Impact
During the 1970’s, digital quartz watches were developed that used LEDs or LCDs instead of gears that turned numbered cards. Pocket calculators that consumed little power evolved from the development of LED and LCD displays. The 1970’s marked the development of LED and LCD displays that continued to replace the once widely used cathode ray tube (CRT) for screen displays. LCD and LED screens came to be used in a multitude of applications that continued to grow, ranging from cellular phones to pocket-sized portable television sets and laptop computers to jumbo television displays. Display screens using LCDs coupled with LEDs continued to be developed for a variety of applications.
Bibliography
Bloomfield, Louis A. How Things Work: The Physics of Everyday Life. New York: John Wiley & Sons, 1997.
Fukuda, Mitsuo. Reliability and Degradation of Semiconductor Lasers and LEDs. Boston: Artech House, 1991.
Lueder, Ernst. Liquid Crystal Displays. New York: John Wiley & Sons, 2001.