China
Africa
Explore chapters and articles related to this topic
Introduction to Additive Manufacturing and 3D Printing Technology
Published in G.K. Awari, C.S. Thorat, Vishwjeet Ambade, D.P. Kothari, Additive Manufacturing and 3D Printing Technology, 2021
G.K. Awari, C.S. Thorat, Vishwjeet Ambade, D.P. Kothari
Looking at digital light processing machines, these types of 3D printing technology are almost the same as SLA. The key difference is that DLP uses a digital light projector to flash a single image of each layer all at once (or multiple flashes for larger parts).Because the projector is a digital screen, the image of each layer is composed of square pixels, resulting in a layer formed from small rectangular blocks called voxels. DLP can achieve faster print as compared to SLA. That’s because an entire layer is exposed all at once, rather than tracing the cross-sectional area with the point of a laser. Light is projected onto the resin using light-emitting diode (LED) screens or a UV light source (lamp) that is directed to the build surface by a digital micromirror device (DMD). A DMD is an array of micro-mirrors that control where light is projected and generate the light-pattern on the build surface.
Increasing Projector Contrast and Brightness through Light Redirection
Published in Khosla Ajit, Kim Dongsoo, Iniewski Krzysztof, Optical Imaging Devices, 2017
Hoskinson Reynald, Stoeber Boris
To explain our proposal for a high-contrast projector using an auxiliary mirror array, it helps to first outline the architecture of a modern projector system. Most projection displays available today are based on either digital light projection (DLP) or liquid crystal on silicon (LCoS). They differ in the type of light valve used, the element that selectively blocks light. A lamp provides uniform illumination to the light valve, and the liquid crystals in the LCoS, for example, selectively reduce illumination of a pixel on the screen in order to form the dark parts of the image. The digital micro-mirror device (DMD) inside a DLP projector functions in a similar manner. A DMD is an array of micromirrors, one for each pixel, each one of which can be tilted in one direction so that incident light reflects toward the projection lens and then out onto the screen, or in another direction so the light is reflected to a heat sink and that spot on the screen remains dark.
Microtools and Toys: MEMS, NEMS, and BioMEMS
Published in John D. Cressler, Silicon Earth, 2017
Gigantic, high-definition TV (HDTV) displays bring a movie-house-like experience into the home. Bravo for movie-buffs like me! Depending on your needs (and $!), you have several options. You can buy either a high-resolution LCD, a plasma display, or something called a DLPTM (Digital Light Projection) HDTV display (Figure 10.30). Interestingly enough, this latter type of HDTV display is based on a sophisticated MEMS chip tour de force (Figure 10.31). Read on. In 1987, from seemingly out of nowhere, Larry J. Hornbeck of Texas Instruments introduced the Digital Micromirror Device (DMDTM), patented on October 7, 1986 (U.S. Patent 4,615,595) [3]. A DMD is a MEMS gadget consisting of a 2D array of steerable MEMS optical-mirror pixels fabricated on a silicon substrate by surface micromachining. Each MEMS pixel is made up of a reflective aluminum micromirror supported on a central post, and this post is mounted on a lower aluminum platform, the mirror “yoke” (Figures 10.32 and 10.33). The yoke is then suspended above the silicon substrate by compliant L-shaped hinges anchored to the substrate by two stationary posts. As you might imagine, control electronics are then embedded in the silicon wafer under each pixel. The two bias electrodes can tilt the micromirror either +10° or −10° with the application of 24 V between one of the electrodes and the yoke (Figures 10.34 and 10.35). In other words, we can controllably steer the micromirror!
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.
Benchmarking modern algorithms to holographically create optical tweezers for laser-cooled atoms
Published in Journal of Modern Optics, 2018
Naomi Holland, Dustin Stuart, Oliver Barter, Axel Kuhn
As we have said, the physical device used to create the hologram may only modulate either the amplitude or the phase of the light, but not both simultaneously. A DMD consists of a large array of micro-mechanical mirrors in which each mirror can be switched between two different angles, which we refer to as ‘0’ and ‘1’. A mirror in the ‘1’ position reflects light through the remainder of the optical setup whereas a mirror in the ‘0’ position deflects light towards a beam stop, thus acting as a binary amplitude modulator. A typical full frame rate for such a device is . In contrast, PSLMs are 1–2 orders of magnitude slower, but they offer the advantage of improved control over the hologram, since despite no amplitude control, they permit a quasi-continuous modulation of the phase between 0 and . In a liquid crystal PSLM, an applied voltage across each of the pixels of the device causes the phase of the light traversing that pixel to be modulated by an amount proportional to that voltage. For a digitally controlled PSLM, the standard response time is , and 256 phase levels are the norm.
An ultrashort throw ratio projection lens design based on a catadioptric structure
Published in Journal of Modern Optics, 2018
The specifications of the UST lens are shown in Table 1. For a 0.3 inch DMD chip, the pixel size is 7.6 μm and the resolution is 854 × 480. In this design, there is the lateral displacement of the DMD chip from the optical axis because the surface 2 and surface 3 produce the blind area in the CPL lens (12). Therefore, in order to avoid the blind area, the object height is set to 5.45 mm, and the off-set is set to 3.374 mm. The effective focal length of the UST lens is about −1.97 mm. In order to get an ultrashort throw ratio, a diagonal screen size of 80 inch and 410 mm projection distance are adopted in the UST lens design. Consequently, the throw ratio of the UST lens is 0.23 and magnification is about 269×. Finally, an ultrashort throw ratio projector system is obtained based on this design.