LCD

LCD
Béotien lambda · CC BY-SA 3.0 · source
Name	Liquid crystal display
Invented	1968
Inventor	George H. Heilmeier
Developer	RCA Corporation, Texas Instruments, Hitachi, Sharp Corporation
Type	Flat-panel display
Introduced	1970s

LCD

Liquid crystal display technology uses anisotropic organic materials whose optical properties are controlled by electric fields to form images. LCDs revolutionized visual interfaces across consumer electronics, instrumentation, telecommunications, and aerospace by offering thin, low-power, and high-resolution screens. Major corporations such as Sony Corporation, Samsung Electronics, LG Electronics, Panasonic Corporation, and Apple Inc. drove adoption alongside research institutions like MIT, Stanford University, and Bell Labs.

Introduction

LCDs employ liquid crystals—mesophases discovered in the late 19th century by Friedrich Reinitzer and Otto Lehmann—to modulate light between polarizers under electronic control. Early practical implementations were advanced by engineers including George H. Heilmeier and companies like RCA Corporation that translated laboratory effects into products. The result displaced bulkier cathode-ray tubes made by firms such as RCA and Philips N.V. in many applications, and competed with emerging technologies from Sony Corporation (TRINITRON) and later Samsung Electronics (AMOLED development).

History and Development

Liquid crystal phenomena were first characterized in studies referenced by Reinitzer and Lehmann, then explored theoretically by Pierre-Gilles de Gennes whose work earned a Nobel Prize in Physics and informed device physics. In the 1960s and 1970s, researchers at RCA Corporation, Hitachi, Sharp Corporation, and Toshiba Corporation developed twisted nematic (TN) cells and multiplexed driving schemes. The 1980s and 1990s saw commercialization by Sharp with pocket calculators and by Casio Computer Co. and Seiko Epson in digital watches. Panel-size, resolution, and backlighting evolved through contributions by IBM, Canon Inc., Fujitsu Limited, and Samsung; by the 2000s thin-film transistor (TFT) active-matrix designs from Sony and LG enabled laptop and HDTV markets, challenging plasma displays marketed by Panasonic and Mitsubishi Electric.

Technology and Operation

Liquid crystals are organic compounds that exhibit order between crystalline and isotropic liquid phases; common types used in displays include nematic and smectic mesogens synthesized by chemical firms like Merck KGaA and BASF. In a typical LCD cell, substrates coated with transparent conductors such as indium tin oxide (ITO) and alignment layers orient liquid crystal molecules; the optical state between crossed polarizers is modulated by an applied voltage sourced from driver integrated circuits by vendors like Texas Instruments and Rohm Semiconductor. Active-matrix addressing uses thin-film transistors (TFTs) based on amorphous silicon or low-temperature polycrystalline silicon developed with processes from Intel Corporation and TSMC. Backlighting historically used cold-cathode fluorescent lamps from Osram and later light-emitting diode arrays supplied by Nichia Corporation and Cree, Inc.; color is produced using color filters patterned by Kodak-derived dye technologies and subpixel arrangements standardized by industry alliances including VESA.

Types of LCD Displays

Several architectures target tradeoffs among contrast, viewing angle, response time, and cost. Twisted nematic (TN) panels, pioneered by RCA and Sharp Corporation, offer fast response for gaming equipment from NVIDIA Corporation and AMD but limited viewing angles. In-plane switching (IPS), developed with roots at Hitachi and commercialized by LG Display, provides wide viewing angles for professional monitors by Dell Inc. and Apple Inc.. Vertical alignment (VA), used by Samsung Electronics and Philips N.V., balances contrast and black levels for televisions by Sony and Panasonic. Other variants include fringe-field switching (FFS), patterned vertical alignment (PVA/MVA) by Fujitsu and Chunghwa Picture Tubes, and transflective designs for handhelds by Nokia Corporation and Motorola.

Manufacturing and Materials

LCD panel fabrication occurs in cleanrooms at fabs operated by Samsung Display, LG Display, BOE Technology Group, and AU Optronics. Processes include photolithography, sputtering of ITO, chemical vapor deposition, and alignment rubbing or photoalignment developed in cooperation with suppliers like Applied Materials and KLA Corporation. Glass substrates historically came from Corning Incorporated and Nippon Electric Glass; flexible substrates employ polyimide films sourced from DuPont and Toray Industries. Liquid crystal chemistries and colorant formulations are supplied by specialty chemical firms including DIC Corporation and Clariant AG. Quality control leverages metrology tools from ZEISS and Hitachi High-Technologies and follows standards set by ISO and industry consortia.

Applications and Markets

LCDs dominate markets for laptop computers by Lenovo Group, HP Inc., and Acer Inc.; smartphone displays by Apple Inc. and Samsung Electronics have alternated between LCD and OLED choices. Televisions manufactured by Sony Corporation, LG Electronics, TCL Technology, and Hisense use large-format LCD panels with LED backlighting. Instrumentation panels in aircraft such as those by Boeing and Airbus employ ruggedized LCDs from companies including Collins Aerospace. Medical imaging devices by GE Healthcare and Siemens Healthineers use high-grade IPS panels; industrial controls from Siemens AG and Schneider Electric incorporate sunlight-readable transflective LCDs. Global supply chains are influenced by trade policies involving United States, China, Japan, and South Korea.

Limitations and Future Trends

LCDs face constraints in contrast ratio, black level, and flexibility compared with emissive alternatives like OLED produced by Samsung Display and LG Display. Efforts to improve performance include quantum-dot enhancement from Nanosys and local dimming arrays integrated by Sony and Samsung Electronics. Research into blue-phase liquid crystals and microLED backplanes involves institutions such as MIT, Stanford University, and companies including Apple Inc. and Google LLC. Sustainability and material supply issues center on indium availability and recycling initiatives from Umicore and regulatory frameworks in the European Union. While OLED and microLED target premium segments, LCD variants continue to evolve in efficiency and cost, sustaining large shares of panels supplied by BOE Technology Group and LG Display.

Category:Display technology