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Increasing Projector Contrast and Brightness through Light Redirection
Published in Laurent A. Francis, Krzysztof Iniewski, Novel Advances in Microsystems Technologies and Their Applications, 2017
Reynald Hoskinson, Boris Stoeber
All projectors can be broken down into a number of functional subsections. Figure 9.1 shows the subsections of single-chip DLP projectors. For purposes of clarity, only the light reaching one pixel of the DMD is shown; in reality there is a ray bundle that reaches each pixel of the DMD. First, in the light path, a reflector collects the light from a small lamp or LED and directs it into the illumination optics. In a single-chip DLP projector, the lamp reflector minimizes the spot size of the light at the colour wheel. After, the colour wheel is the integrator, which spatially redistributes the image of the light source from a highly peaked to a more uniform distribution with an aspect ratio that matches that of the light valve. This affects the final distribution of the light on the screen. For DLP projectors, the integrator is usually a rod, made of hollow mirrored tunnels. From the integrator rod, the light travels through relay/folding optics, which form an image of the integrator rod face on the DMD. The image of the DMD is then transmitted to the screen using a projection lens system.
Lighting and Communications: Devices and Systems
Published in Zabih Ghassemlooy, Luis Nero Alves, Stanislav Zvánovec, Mohammad-Ali Khalighi, Visible Light Communications, 2017
Luis Nero Alves, Luis Rodrigues, José Luis Cura
Figure 2.1 depicts a conceptual overview of the main blocks in a typical lighting system. The four main components are the power source (PS), the lighting device (D), a reflector (R), and a shaping lens (L). Note that the physical enclosure for the lamp is not shown in Figure 2.1; this will not be covered in this chapter. Each of the components depicted in Figure 2.1 have a specific functionality. The PS is the energy provider, which is responsible for controlling and providing energy to the lighting device. Different lighting devices may have different requirements for the PS, which usually have different names. For instance, a driver for a light-emitting diode (LED), ballast for fluorescent lamps. The next element is the lighting device where the electrical energy is converted into light. There are several types of lighting devices with different conversion mechanisms, each suitable for different applications. The most common lighting devices available on the market are fluorescent lamps, compact fluorescent lamps (CFL), high-intensity discharge lamps (HIDs), LEDs, and more recently, laser-based visible lights [1,2]. The incandescent lamps with very low energy efficiency are being phased out at a global level. The reflector element is used to confine the light radiation in a specific direction. And finally, a shaping lens is employed to assure uniform lighting conditions.
New Methods of Analysis
Published in Boris Levin, Antennas, 2021
An example of such structure is the in-phase reflector array (Fig. 4.19a). It is a flat equivalent of a parabolic reflector. The structure consists of primary exciter 1 of antenna array (e.g., a horn) and an equally spaced array of secondary microstrip radiators 2, situated in one plane along surface 3. In order to sum the signals of secondary radiators in a direction, perpendicular to the array plane, their phases should be identical. Since distances r, (i is the radiator number) between the primary exciter and an arbitrary reradiator are not identical, this results in a phase path difference, which should be compensated with a phase shift in the reradiating signal.
Axially symmetric reflector antennas: Geometrical-optics models and efficient electrodynamic analysis of double-mirror structures
Published in Electromagnetics, 2020
Yuriy Sirenko, Paul Smith, Lyudmyla Velychko, Olena Velychko
Reflector antennas are quite widespread, being the main type of antennas currently used in radio location, space communication, radio astronomy, and electronic countermeasure sets. This is due to the simplicity of design and mechanical strength of these antennas, their bandwidth, high efficiency, and relative ease way of forming different radiation patterns. In the development of specific devices of this kind, particularly problematic have been issues related to the determination of the optimum wave dimensions of the mirrors, their precise relative position, the choice of optimal design, and electrodynamic compatibility of all major functional elements of the antenna feeder. Electrodynamic modeling and numerical experiments turn out to be helpful and rather efficient in dealing with these issues that continue to be problematic.
The effect of the reflective property of a reflection film on the performance of backlight units with quantum-dot films for LCD applications
Published in Journal of Information Display, 2021
Gi Jung Lee, Jung-Gyun Lee, Younduk Kim, Taehee Park, Young Wook Ko, Jae-Hyeon Ko
Optical simulation for the backlight unit with QD films using the ray-tracing technique was carried out for comparison with the experiment results. A commercial software (LightTools, Synopsys) was used for the simulation. The absorption, excitation, and emission spectra of both QDs were adopted from the reported values [13]. The mean free path of the QDs in the film was adjusted to control the density of the QD particles. Two kinds of reflectors were adopted: one was a perfect specular reflector and the other, a diffuse reflector with a Gaussian distribution that had a spreading angle of ± 10°. The detailed simulation conditions are shown in Tables 1 and 2.
A compact CPW-fed wideband slot antenna with reflector for wireless communication
Published in Electromagnetics, 2019
Amrita Gorai, Bappadittya Roy, G.K. Mahanti
In the proposed article, an effort has been made to design a simple single-feed patch antenna with a metallic reflector having circular polarization and a wideband characteristic. The use of metallic reflector aids in the increase of the gain of the antenna. The antenna has a co-planar waveguide feed and a pentagonal patch nested within an asymmetrical pentagonal slot on the ground plane. A considerable 3 dB axial ratio bandwidth is achieved along with a good overall gain of 6.64 dBi in the desired frequency band. The results are simulated and studied in HFSS to minimize the errors by ensuring that the mesh used was sufficiently fine.