A graded-index optical element may include a nanovoided material including a first surface and a second surface opposite the first surface. The nanovoided material may be transparent between the first surface and the second surface. Additionally, the nanovoided material may have a predefined change in effective refractive index in at least one axis due to a change in at least one of nanovoid size or nanovoid distribution along the at least one axis. Various other elements, devices, systems, materials, and methods are also disclosed.

Disclosed herein are devices that change their appearance and/or physical properties when under an external influence, and methods for their production and use. Such devices may be used as features of any type of items, documents, billboards, posters, display devices, advertisements and other items etc. and may be adapted to include decipherable content. Such devices also afford new techniques for a user to check quickly and easily whether the item is a legitimate or a counterfeit copy, either by hand-manipulation of the device, or with the assistance of an additional screening tool.

The present invention relates to methods for calibrating and controlling a polarization modulator, for example a photoelastic modulator (PEM) device on a CD measurement instrument, the method comprising scanning the control input voltage (V.sub.in) at a fixed wavelength (.sub.meas); and recording the CD scan, wherein the control input voltage (V.sub.in) determines the peak retardation () at the fixed wavelength (.sub.meas), and wherein the method is repeated for one or more fixed wavelengths. An augmented drive function allows the PEM to be operated with greater accuracy over the full wavelength range, and measurement of resonant frequency provides a means to continually correct for temperature related drift of retardation.

The present disclosure discloses an electronic device, to solve the technical problem that it is relatively complex to implement a change in color of an appearance of the electronic device in the related art. The electronic device comprises a main body having a basic form and a deformed form; and a color changing film attached to the main body to form a part of a surface of an appearance of the main body, the color changing film being deformed as the main body is changed from the basic form to the deformed form, wherein if the main body is in the basic form, the color changing film as the part of the appearance of the main body presents a first visual effect, and if the main body is in the deformed form, the color changing film as the part of the appearance of the main body presents a second visual effect different from the first visual effect. Based on the same concept, the present disclosure further discloses another electronic device.

An apparatus includes a photoelastic modulator (PEM) optical element including a first driving axis and a second driving axis arranged at a selected angle with respect to each other and perpendicular to an optical axis, wherein the first driving axis and the second driving axis extend respective predetermined non-equal lengths that correspond to respective predetermined non-equal natural first and second PEM frequencies f.sub.1 and f.sub.2. Methods of manufacture and operation are also disclosed.

An imaging system includes an indicator installed around an antenna, wherein optical characteristics of the indicator change as a function of an electromagnetic field formed by the antenna, an imaging apparatus for imaging a change in optical characteristics of the indicator, a transmitter for radiating radio waves toward the antenna, and a receiver for receiving a signal from the antenna.

The present application discloses a display panel free of a liquid crystal layer including a base substrate, and an array of a plurality of pixels on the base substrate, each of the plurality of pixels comprising at least one subpixel. Each subpixel includes an electroactive layer on the base substrate; and a light transmission layer on the base substrate configured to be actuated by the electroactive layer so that light transmittance of the light transmission layer in the at least one subpixel changes in response to a change in an electrical signal applied to the electroactive layer to achieve levels of gray scale; wherein the light transmission layer is reversibly deformable.

Disclosed herein are devices that change their appearance and/or physical properties when under an external influence, and methods for their production and use. Such devices may be used as features of any type of items, documents, billboards, posters, display devices, advertisements and other items etc. and may be adapted to include decipherable content. Such devices also afford new techniques for a user to check quickly and easily whether the item is a legitimate or a counterfeit copy, either by hand-manipulation of the device, or with the assistance of an additional screening tool.

The present invention provides an array substrate comprising a transparent substrate and a polarizer attached on the transparent substrate, the polarizer comprises a first protective layer in contact with the transparent substrate, and a relational expression is satisfied between the first protective layer and the transparent substrate, 0|C|1.010.sup.13, wherein C is defined by the equation $C=\frac{C_{100}{}_{100}{d}_{100}}{{}_{100}{d}_{100}+{}_{200}{d}_{200}}+\frac{C_{200}{}_{200}{d}_{200}}{{}_{100}{d}_{100}+{}_{200}{d}_{200}}.$
When designing an array substrate provided by this invention, it is not required to consider the improvement of the material of the polarizer, and it may be ensured that the change of photoelastic birefringence of a finally formed array substrate is zero (or close to zero) in the case of being subjected to stress by only adjusting the thickness of a first protective layer or the material of the first protective layer, such that the phenomenon of light leakage of a finally formed liquid crystal display panel generated due to photoelastic birefringen

A display device includes: a plurality of pixel units, where each pixel unit includes two suppression color changing sub-pixel units configured for exciting light waves of different colors. Each suppression color changing sub-pixel unit includes: a first transparent electrostatic sheet and a second transparent electrostatic sheet which are disposed opposite to each other and insulated from each other, where the first transparent electrostatic sheet is disposed on a substrate and the second transparent electrostatic sheet is disposed on the first transparent electrostatic sheet. The display device further includes: a suppression color changing light emitting layer disposed between the first transparent electrostatic sheet and the second transparent electrostatic sheet; and a transparent pressure deformation sensor disposed at a side of the second transparent electrostatic that is away from the substrate.