A higher color gamut can bring more comfort to one’s watching experience; therefore, it is a key aspect when assessing the quality of the display. To improve the color gamut of a display, many techniques have been used. Although some techniques have been claimed to work, the overall quality of the color gamut of the display still does not satisfy many researchers. In this paper, we will consider several key factors that can affect the color gamut of the newly developed laser display system, including the center wavelength of the Quantum dot film, the efficiency of the Brightness Enhancement Film, and the quality of the color filter of the liquid crystal display panel. An improvement of nearly 45% can be achieved through fine tuning of the key factors when compared with our earlier models without finetuned ones. The average color gamut of the laser quantum dot backlight display system can reach up to 110% NTSC color gamut that yields vivid color results.
Luminance is a key factor for outside displays because of background light interference. Many methods have been used to enhance the luminance of backlit display systems. The key to enhancing the luminance of a backlit system is to increase the light coupling between the light guided plate (LGP) and the light source. In this paper, we present an effective method to enhance light trapping and boost light harvesting by introducing cross-grooved textures on the side surface of the LGP. Elevated light coupling between the line laser and the LGP with a cross-grooved texture has been observed in both 3 mm and 4 mm thick LGPs, respectively. A light trapping mechanism has been proposed in which greater interaction surface area between the LGP and line laser source and an elongated light traveling channel contribute to overall light trapping. As a result, reduced reflection loss boosts light harvesting. A nearly 100% luminance efficiency enhancement has been achieved using this simple technique.
Nanocrystalline cellulose (NCC) exhibits unusual optical properties that make it of interest for hierarchical optical
encryption in nanostructured films. The color-travel phenomenon of iridescence is exhibited by NCC when cast as a film
from chiral nematic aqueous phase suspensions of the nanocrystals. “Iridescence by self-assembly” has potential for
overt encryption as an anti-counterfeiting measure. It also offers an intrinsic level of covert encryption by reflecting leftcircularly
polarized light. We show that addition of a UV sensitive dye adds another level of (covert) encryption, and
that specially prepared films manifest a rare form of optical non-reciprocity that does not require the application of an
external field. Chirality parameters and stokes vector analyses suggest a simple authentication scheme. The method uses
a UV light source and a circular polarizer in conjunction with an iridescent feature that can be verified by the eye or by
chiral spectrometry.
Nanocrystalline cellulose (NCC) solid films derived from spruce pulp exhibit iridescence when cast from chiral nematic aqueous phase suspensions of the nanocrystals. The iridescence has potential for overt encryption as an anti-counterfeiting measure and also offers an intrinsic level of covert encryption since films of NCC reflect left-circularly polarized light. Addition of TINOPAL, an optical brightening agent (OBA), adds a third level of (covert) encryption potential since the chromophore exhibits strong fluorescence when excited with ultraviolet (UV) light. The overall result is a selectively polarizing fluorescent iridescent film. We examined the impact of additions of OBA on NCC iridescence, optical activity, and physical structure variation with polarized optical microscopy, circular dichroism (CD) spectropolarimetry, and zeta potential analysis. Increasing OBA additions increase the chiral nematic pitch of NCC films and alter chiral nematic domain structure in the solid film. Under low-concentration conditions, OBA yields intense UV fluorescence without compromising the visible light iridescent properties of the film. The potential security offered by the NCC film can be authenticated using a UV light source, a circular polarizer in conjunction with an iridescent feature that can be verified by the eye or by chiral spectrometry.
Nanocrystalline cellulose solid films derived from spruce pulp exhibit iridescence when cast from chiral nematic
aqueous phase suspensions of the nanocrystals. Iridescence is a color travel phenomenon that might have potential for
overt encryption as an anti-counterfeiting measure. The iridescent phase also offers an intrinsic level of covert
encryption by virtue of the fact that films of NCC reflect left-circularly polarized light. Addition of TINOPAL, an
optical brightening agent (OBA), adds a third level of (covert) encryption potential since the chromophore exhibits
strong fluorescence when excited at ultra-violet wavelengths. The overall result is a selectively polarizing fluorescent
iridescent film. We study the impact of additions of OBA on NCC iridescence, optical activity, and physical structure
variation with polarized optical microscopy, circular dichroism spectropolarimetry and zeta potential analysis. Increasing
OBA additions increase the chiral nematic pitch of NCC films, and this in turn alters chiral nematic domain structure in
the solid film. Under low concentration conditions defined by our experiments, OBA yields intense UV fluorescence,
without compromising the visible light iridescent properties of the film. The potential security offered by NCC and its
optical responses can be authenticated using a UV light source such as is commonly used for banknote verification, a
circular polarizer in conjunction with an iridescent feature which can be verified by the eye or by chiral spectrometry.
Nano Crystalline Cellulose (NCC) in aqueous suspension gives rise to anisotropic order that leads to iridescence from
the fluid phase. Phase separation and order formation were studied using polarized optical microscopy and laser
diffraction. Factors affecting liquid crystal phase separation, such as hydrolysis time, wood pulp species, sonication
are discussed. Long range order and a physical grating structure are important to produce iridescence in the bulk fluid
liquid crystal phase Stereomicroscopy showed that retardation lines propagate through the bulk of the fluid. Laser
diffraction light experiments reveal features of the time evolution of the bulk grating. The grating structure may be
used as tool to cast a chiral iridescence grating for security applications.
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