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Video Basics
Published in Wes Simpson, Video Over IP, 2013
Liquid crystal displays (LCDs) use liquid crystals (chemicals that can be used to block or pass light based on an electrical signal) and a light source to create a viewable image, either directly on a glass sheet or by projecting the light onto a screen. Plasma displays use electron beams and phosphors just like a CRT, except each pixel has its own microscopic beam source. Large outdoor displays can use thousands upon thousands of light-emitting diodes (LEDs, just like the ones used as power indicators on electronic devices) in three different colors to create an image. And finally, Digital Light Processing® (DLP) projectors use devices from Texas Instruments containing millions of movable microscopic mirrors to reflect light from three different color light sources onto a display screen.
The Home Cinema
Published in Lars-Ingemar Lundström, Understanding Digital Television, 2012
The competing technology is DLP, digital light processing and consists of a matrix with hundreds of thousands small mirrors whose orientation can be affected by electrical signals in the same way as the pixels in plasmas or LCDs. The micro-mirror chip is generally called DMD, for digital micro-mirror device. By pointing the mirrors in the right direction, the light from that pixel will be exposed on the projection screen. It is very similar to when you are traveling by car and suddenly get a reflection of the sun in a window that happens to be in the right angle to reflect the light straight towards you. The advantage in the DLP technology is that the contrast ratio in the picture will be much better than for LCD. The risk for the device to be over-heated by the light source is also much lower than in LCDs, since the light is reflected. This also makes it possible to use very bright light sources. In most cases only one DLP is used to produce all three colors. The three basic color pictures are produced in sequence by letting the light pass a rotating wheel with filters corresponding to the three basic colors (see Figure 11.7).
Projection
Published in Charles S. Swartz, Understanding Digital Cinema, 2004
The need for maintenance is an often-asked question. Digital projectors have no moving parts other than cooling fans. They are inherently reliable, but there is routine maintenance to be carried out. Lamp. As in a film projector, the lamp loses efficiency as it is used. To maintain optimal performance, the light output must be adjusted periodically to sustain specified brightness. This period is on the order of weeks. After 1000 to 2000 hours, the lamp will no longer output sufficient light for the screen and must be replaced.Dust and dirt filters. Periodically, the air filter must be changed. In addition, the optics may need to be cleaned to maintain optimum performance. Several versions of DLP Cinema™ projectors have sealed optical systems, substantially reducing the need for cleaning.Convergence. The alignment of the modulators may periodically drift and require touch-up. This should be done annually.
Driving Towards the Future: Exploring Human-Centered Design and Experiment of Glazing Projection Display Systems for Autonomous Vehicles
Published in International Journal of Human–Computer Interaction, 2023
Yancong Zhu, Yunke Geng, Ruonan Huang, Xiaonan Zhang, Lu Wang, Wei Liu
The advancement of automotive glazing projection display technology is primarily attributed to hardware technology development (Lampert, 2003; Sadek & Mahrous, 2018). In projection technology research, Digital Light Processing (DLP) technology is employed as the projection source (Kadry et al., 2019). Texas Instruments Digital Micromirror Device (DMD) is the basis for DLP technology, which allows for the digital visual display of information (Yang et al., 2021). DMD rapidly switches pixels and blends the three RGB primary colors to produce a vivid and realistic image. DLP technology has a significant performance advantage since its switching characteristics remain stable despite changes in temperature, which maintains image quality and color reproduction. Sunlight backflow is prevented, and projection clarity is enhanced through temperature control. The placement of the DLP projector determines front or rear projection, and information can be displayed on the windshield inside and outside the vehicle. Unlike W-HUD, DLP projection produces an authentic image visible from any position within the vehicle.
Particulate suspension: a review of studies characterizing particulates and volatile organic compounds emissions during additive manufacturing processes
Published in Particulate Science and Technology, 2023
Sayed Kaes Maruf Hossain, Azul Toledo Vega, Delia Valles-Rosales, Young Ho Park, Sarada Kuravi, Hansuk Sohn
VAT Photopolymerization involves exposing liquid resins to controlled light to harden the resin at a specific location, layer by layer. The more conventional technique in this group is Stereolithography (SLA). More recent technology involves Digital Light Processing (DLP). A study by Stefaniak, Bowers, et al. (2019) reported that the particulates and TVOC emissions during the VATP process were similar to or exceeded other AM processes, including Material Extrusion, especially peaking during the beginning and end of the printing process. Interestingly, the DLP type printers caused higher mean particles and TVOC yield than SLA type printers. The geometric mean of particles emitted from DLP type printers was smaller than SLA type printers. The authors identified this as an indication of how the underlying printing technology can help control exposure.
Use of additive manufacturing for the fabrication of cellular and lattice materials: a review
Published in Materials and Manufacturing Processes, 2021
Esmeralda Uribe-Lam, Cecilia D. Treviño-Quintanilla, Enrique Cuan-Urquizo, Oscar Olvera-Silva
The digital light processing (DLP) technique uses a projection mechanism that screens a single image which represents the 2D version of each layer, producing small square volumetric pixels (voxels).[76] Luxner and coworkers [77] used digital light processing and selective laser sintering (SLS) to produce different cellular materials simple cubic (SC) (Fig. 5c), body-centered cubic (BCC) (Fig. 5d) and Gibson – Ashby (GA) (Fig. 5e). They compared their relative density, stiffness, and directional dependence on their apparent Young’s moduli obtained both experimentally and computationally. The digital light processing (DLP) lattice structures were created with a 40 mm pixel resolution, considered as high resolution, and a 0.2 mm wall thickness; smaller when compared with the 0.4 mm wall thickness of selective laser sintering. The fabrication times were very similar for all the structures in this study. The main advantages of digital light processing in comparison with selective laser sintering are the fabrication time and no-support requirement for the manufacturing of lattice materials and porous structures. Digital light processing is an ideal alternative to produce lightweight ceramic structures as triply periodic minimal surfaces. The parts fabricated by digital light processing and a sintering process show homogeneity at the grain size, but the organic components of the resins may cause the formation of porous structures in the material.[78]