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Smart Materials and Devices for Human-Centric Lighting
Published in Tuan Anh Nguyen, Ram K. Gupta, Nanotechnology for Light Pollution Reduction, 2023
The OLED is fundamentally different from the LED. A p-n diode structure is used in LED and the conductivity of the host semiconductor is changed by doping. However, OLEDs do not use the p-n structures. Doping of OLEDs is used to increase radiative efficiency by direct modification of the quantum-mechanical optical recombination rate. Thus, in OLEDs, doping is used to determine the wavelength of photon emission. Adding mobile ions to an OLED could create a light-emitting electrochemical cell (LEC). An OLED display can be driven with a passive-matrix (PMOLED) or active-matrix (AMOLED) control scheme. In the PMOLED scheme, each row (and line) in the display is controlled sequentially, one by one, whereas AMOLED control uses a thin-film transistor (TFT) backplane to directly access and switches each pixel on or off, allowing for higher resolution and larger display sizes. Since the OLED emits visible light, the OLED display works without a backlight. Thus, OLEDs can display deep black levels and can be thinner and lighter than a liquid crystal display (LCD). OLEDs are mostly used as digital displays in model devices. However, currently, many works focus on the applications [9–11].
Green Electronics for Future Communication Systems
Published in Gurjit Kaur, Akanksha Srivastava, Green Communication Technologies for Future Networks, 2023
Sakshi Mittal, Gurjit Kaur, Manjeet Kumar
Light emitting diode, which generates heat in the form of light energy was first introduced in 1962. They work on the principle of electroluminescence. They offer a good picture quality but consume more power. LEDs were replaced by OLEDs in 1987. OLED or organic LED involves organic material in between conducting layers. Backlight is not required in the case of OLED as it works on the principle of self-luminescence (Sujith et al., 2020). They have comparatively better picture quality and consume less power. But they came at high cost and are less flexible as compared to LEDs.
Design of a new in-flight entertainment terminal
Published in Jimmy C.M. Kao, Wen-Pei Sung, Civil, Architecture and Environmental Engineering, 2017
Hairong Xu, Hong Zhou, Hui Yang
Traditional display device uses Liquid Crystal Display (LCD) panel as the output. A backlight system is used for display module, as LCD does not produce light by itself. LCD needs illumination (ambient light or a special light source) to produce a visible image.
A novel monitor for practical brain-computer interface applications based on visual evoked potential
Published in Brain-Computer Interfaces, 2021
Hamidreza Maymandi, Jorge Luis Perez Benitez, F. Gallegos-Funes, J. A. Perez Benitez
In VEP-based BCI, the user communicates with a computer via a graphical interface that is drawn from LCD. A graphical user interface (GUI) is generally an image that includes a set of computer icons or symbols that indicate the commands. Therefore, LCD is the first part of a monitor that allows a user to communicate with the computer via an image that is drawn on it. The image is a combination of millions of small red, blue, and green transistors arranged in groups of three to form picture elements (pixels). These pixels must be illuminated to be visible. As the LCD panel cannot produce its light, in a conventional monitor a backlight, a light source located behind the panel, provides needed light. Figure 3 illustrates the front view of the proposed monitor. The red rectangle shows the LCD including the black area (the blue rectangle) and the matrix part (the green rectangle). Ambient light can produce shift gaze effects on the subject and decrease the signal-to-noise ratio; therefore, a monitor hood surrounds the display (the purple rectangle).
Do users perceive the same image differently? Comparison of OLED and LCD in mobile HMDs and smartphones
Published in Journal of Information Display, 2019
Mobile displays have been undergoing tremendous advances of late in terms of technology, and the market is currently divided into two dominant panels: OLED and LCD. Within the past 10 years, the research on OLED and LCD has yielded remarkable results. Most LCD screens are being designed with a LED (light-emitting diode) backlight, and such backlight is dynamically controlled with dynamic backlight control [6]. This makes the screen brighter on average, and cleaner white, compared to OLED. The LCD technology has become the dominant display technology for products like televisions, laptops, tablets, and smartphones, but the competing OLED technology has been pushed into the market.