Abstract— We have developed a new technique for the production of thin crystal film (TCF) by deposition, molecular alignment, and the drying of water‐based lyotropic‐liquid‐crystal (LLC) materials. TCF exhibits high optical anisotropy and birefringence. This paper presents liquid‐crystal‐display (LCD) applications and opportunities for TCF plastic sheet polarizers, retarders, and color‐correction films as well as LCD designs with TCF internal polarizers.
We developed coatable retarders for visible range of light. The Thin Birefringent Film (TBF™) retarders are based on the newly developed family of water-soluble salts of aromatic polycyclic compounds, which absorb light in the ultra violet region of light spectra. TBF™ retarders are produced by coating and subsequent drying of an aqueous formulation on plastic or glass surface, thereby transforming the liquid coating material into molecularly oriented crystalline or amorphous nano-film. The TBF™ retarders are transparent in the whole visible spectral region and exhibit dichroic polarization characteristics in the UV region. We have produced films with thicknesses in the range of 100 nm to 1100 nm. Obtained TBF™ exhibit the negative A-plate birefringence characterized by n ∆ = n e -n 0 = -0.35 at 550nm. The thin form factor and the ability to coat on a variety of substrates give coatable retarders a great degree of design flexibility and advantages in LCD related applications. LCD applications of TBF™ retarders are also discussed.
We have studied a new class of materials for LCD retarders produced by Cascade crystallization method. Advanced materials comprise the amphiphilic compounds and include salts of carboxylic and sulfonic acids with conjugated aromatic cores, which do not absorb light in visible range of light spectra. The Cascade crystallization method of manufacturing of the thin crystalline films (TCF) is based on printing from aqueous solution of lyotropic liquid crystal phase. We have produced and examined a series of retardation films that exhibit properties of negative A-plates. As compared to conventional retardation materials, new retardation films produced with the Cascade crystallization method are strikingly thinner (thickness range is 100 -1000 nm), whereas birefringence is typically much higher (delta n varies from 0.05 to 0.40). Such a broad range of available thickness and retardation values makes feasible tailoring of LCD designs for customer needs. Viewing angle performance of the crossed polarizers is significantly improved in the presence of TCF retardation films, so that the light leakage at oblique incidence decreases several times. Formation of the new coatable stretchiess retardation coatings by a roll-to-roll process can be easily incorporated into the techniques widely used in the LCD industry. The TCF retarders are aimed for LCD HTV application and open up opportunities for the manufacturing cost reduction.
Controlling the phase of light with a high efficiency and precision is essential for applications in imaging, tunable devices, and optical systems. Spatial light modulators (SLMs) based on liquid crystals (LCs) have been regarded as one of the best choices for the generation of phase profiles for the steering of light. The upper glass substrate has an unpatterned electrode for a common electrode, while the lower glass substrate has one-dimensional micro-patterned electrodes for controlling the single pixel level by the applied voltages. By applying different voltages to each electrode to create a sawtooth-shaped phase profile, the collimated input beam is deflected to the desired angle. To maximize the diffraction efficiency (DE) values, an advanced simulation method has been developed to find the optimized phase profile through the analysis of LC director distributions. The resulting diffraction patterns are investigated both computationally and experimentally, with a good agreement between the results obtained. Finally, the beam deflector (BD) system with an advanced driving algorithm has a high 1st order DE, about 60%, 37%, and 7.5% at 1°, 2.5°, and a maximum steering angle of 7.5°, respectively. The LC director distributions in relation to various diffraction angles are simulated and an experimental success in realizing enhanced DE for the beam steering device is presented.
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