Provided is a set of techniques for measuring different properties or parameters of liquid crystal mixtures by applying a driving waveform and measuring the response current and/or the optical response. This may be done by using specific liquid crystal test cells. Also provided are the optimized test cell parameters that are used in the algorithms for calculating the properties.

There is provided a liquid crystal composition that exhibits a sufficiently low viscosity (), a sufficiently low rotational viscosity (1), and a large elastic modulus (K.sub.33) without decreasing the refractive index anisotropy (n) and the nematic phase-isotropic liquid phase transition temperature (T.sub.ni) and without increasing the solid phase-nematic phase transition temperature (T.sub.cn). The liquid crystal display element that uses this liquid crystal composition satisfactorily obtains a pretilt angle and has a high voltage holding ratio (VHR) and high-speed response. Thus, a liquid crystal display element that has no or less alignment defects and display defects such as image sticking, and has high display quality and high response speed is obtained.

A liquid crystal composition having negative dielectric anisotropy, large refractive index anisotropy, and low viscosity and containing as a first component, one or two or more compounds represented by general formula (I) and, as a second component, one or two or more compounds represented by general formula (II), wherein dielectric anisotropy () at 25 C. is 2.0 or less. Also, a liquid crystal display device having high contrast, fast response, and excellent display quality without causing image sticking and display defects.

A vehicle includes a windshield, a display panel, a virtual image optical system forming an optical path of an image light emitted from the display panel onto the windshield, an outer housing, and a control circuit to control the display panel. The outer housing includes an outer case accommodating the virtual image optical system and having the image display panel attached thereto, an upper cover from which the image light is emitted, and a bottom cover covering a bottom portion of the outer case and having fins on an outer surface thereof. The bottom cover accommodates the display panel and the bottom surface of the outer case when fixed to the outer case and the display panel to isolate them from an external space of the outer housing. A heat conductive portion having a thermal conductivity higher than that of air is between the control circuit and the bottom cover.

A liquid crystal composition satisfying at least one characteristic such as high maximum temperature, low minimum temperature, small viscosity, suitable optical anisotropy, large negative dielectric anisotropy, large specific resistance, high stability to UV light or to heat, or having a suitable balance regarding at least two of the characteristics, and an AM device having characteristics such as a short response time, a large voltage holding ratio, a low threshold voltage, a large contrast ratio and a long service life are shown. The liquid crystal composition contains a specific compound having at least three polymerizable groups, and the liquid crystal display device includes the composition. The composition may contain a specific compound having large negative dielectric anisotropy as a first component, and a specific compound having a high maximum temperature or small viscosity as a second component.

A liquid crystal display according to an exemplary embodiment of the invention includes: a first type pixel including first liquid crystal molecules aligned approximately in a first direction; a second type pixel including second liquid crystal molecules aligned approximately in a second direction different from the first direction; a first lower polarizer disposed opposite to the first type pixel and having a transmissive axis approximately parallel to the first direction; and a second lower polarizer disposed opposite to the second type pixel and having a transmissive axis approximately parallel to the second direction.

Systems, devices, and methods for optical waveguides that are well-suited for use in wearable heads-up displays (WHUDs) are described. An optical device comprises an optical waveguide including a volume of optically transparent material, an in-coupler, an out-coupler, a volume of liquid crystal carried by the volume of optically transparent material, and a controller to modulate a refractive index of the volume of liquid crystal. Light is in-coupled into the waveguide and is propagated along a length of the waveguide by total internal. As the light crosses a thickness of the waveguide the light passes through or within the volume of liquid crystal and is refracted according to the modulated refractive index of the volume of liquid crystal. In this way, light signals can be steered to create an image and/or to move an exit pupil of an image. WHUDs that employ such optical waveguides are also described.

Systems, devices, and methods for optical waveguides that are well-suited for use in wearable heads-up displays (WHUDs) are described. An optical device comprises an optical waveguide including a volume of optically transparent material, an in-coupler, an out-coupler, a volume of liquid crystal carried by the volume of optically transparent material, and a controller to modulate a refractive index of the volume of liquid crystal. Light is in-coupled into the waveguide and is propagated along a length of the waveguide by total internal. As the light crosses a thickness of the waveguide the light passes through or within the volume of liquid crystal and is refracted according to the modulated refractive index of the volume of liquid crystal. In this way, light signals can be steered to create an image and/or to move an exit pupil of an image. WHUDs that employ such optical waveguides are also described.

Systems, devices, and methods for optical waveguides that are well-suited for use in wearable heads-up displays (WHUDs) are described. An optical device comprises an optical waveguide including a volume of optically transparent material, an in-coupler, an out-coupler, a volume of liquid crystal carried by the volume of optically transparent material, and a controller to modulate a refractive index of the volume of liquid crystal. Light is in-coupled into the waveguide and is propagated along a length of the waveguide by total internal. As the light crosses a thickness of the waveguide the light passes through or within the volume of liquid crystal and is refracted according to the modulated refractive index of the volume of liquid crystal. In this way, light signals can be steered to create an image and/or to move an exit pupil of an image. WHUDs that employ such optical waveguides are also described.

Systems, devices, and methods for optical waveguides that are well-suited for use in wearable heads-up displays (WHUDs) are described. An optical device comprises an optical waveguide including a volume of optically transparent material, an in-coupler, an out-coupler, a volume of liquid crystal carried by the volume of optically transparent material, and a controller to modulate a refractive index of the volume of liquid crystal. Light is in-coupled into the waveguide and is propagated along a length of the waveguide by total internal. As the light crosses a thickness of the waveguide the light passes through or within the volume of liquid crystal and is refracted according to the modulated refractive index of the volume of liquid crystal. In this way, light signals can be steered to create an image and/or to move an exit pupil of an image. WHUDs that employ such optical waveguides are also described.