Abstract: The present invention is directed to an electrophoretic dispersion comprising charged pigment particles, in particular, an electrophoretic dispersion including both uncharged or lightly charged neutral buoyancy particles and uncharged or lightly charged additive particles. The combination improves the performance of an electrophoretic display, in particular the color state stability over time.

Abstract: In a method of manufacturing a one-dimensionally varying optical filter, a substrate is coated to form a stack of layers of two or more different types. The coating may, for example, employ sputtering, electron-beam evaporation, or thermal evaporation. During the coating, the time-averaged deposition rate is varied along an optical gradient direction by generating reciprocation between a shadow mask and the substrate in a reciprocation direction that is transverse to the optical gradient direction. In some approaches, the shadow mask is periodic with a mask period defined along the direction of reciprocation, and the generated reciprocation has a stroke equal to or greater than the mask period along the direction of reciprocation. The substrate and the shadow mask may also be rotated together as a unit during the coating. Also disclosed are one-dimensionally varying optical filters, such as linear variable filters, made by such methods.

Abstract: The present invention is directed to an electrophoretic fluid which comprises additive particles. The concentration of the additive particles in the electrophoretic fluid does not exceed 25% by weight and the additive particles are not seen at the viewing side during operation of the display. The resulting fluid can improve optical performance of a display device, such as image stability and contrast ratio. The present invention is also directed to an electrophoretic display comprising the electrophoretic fluid.

Abstract: The present invention is directed to an electrophoretic dispersion, in particular, an electrophoretic dispersion comprising uncharged or lightly charged additive particles for improving bistability of an electrophoretic display. The average diameter of the additive particles is about 1% to about 25% of the average hydrodynamic diameter of the charged pigment particles.

Abstract: In a method of manufacturing a one-dimensionally varying optical filter, a substrate is coated to form a stack of layers of two or more different types. The coating may, for example, employ sputtering, electron-beam evaporation, or thermal evaporation. During the coating, the time-averaged deposition rate is varied along an optical gradient direction by generating reciprocation between a shadow mask and the substrate in a reciprocation direction that is transverse to the optical gradient direction. In some approaches, the shadow mask is periodic with a mask period defined along the direction of reciprocation, and the generated reciprocation has a stroke equal to or greater than the mask period along the direction of reciprocation. The substrate and the shadow mask may also be rotated together as a unit during the coating. Also disclosed are one-dimensionally varying optical filters, such as linear variable filters, made by such methods.

Abstract: The present invention is directed to an electrophoretic fluid which comprises additive particles. The concentration of the additive particles in the electrophoretic fluid is 2.5% to 25% by weight and the additive particles are not seen at the viewing side during operation of the display. The resulting fluid can improve optical performance of a display device, such as image stability and contrast ratio. The present invention is also directed to an electrophoretic display comprising the electrophoretic fluid.

Abstract: Phosphor elements comprising phosphors in a host material having a phosphorescence-emitting surface with surface nanostructures are disclosed. Phosphor wheels having such phosphor elements, methods of making such phosphor elements, and methods of using such phosphor elements are also disclosed.

Abstract: This application is directed to driving methods for electrophoretic displays. The driving methods and waveforms have the advantage that they provide a clean and smooth transition from one image to another image, without flashing or other undesired visual interruptions. The methods also provide faster image transitions. In an embodiment, a method drives a display device from a first image to a second image wherein images of a first color are displayed with a background of a second color, which method comprises driving pixels of the first color directly to the second color before driving pixels of the second color directly to the first color.

Abstract: Devices and methods are disclosed for characterizing point flaws (including pinholes and point defects) of an optical filter. A passband test is performed, including: illuminating the optical filter with passband illumination whose spectral range at least overlaps a passband of the optical filter; acquiring a passband map of the optical filter using a two-dimensional array of photodetectors while illuminating the optical filter with the passband illumination; and identifying point defects of the optical filter as low intensity locations of the passband map. A stopband test is performed, including: illuminating the optical filter with stopband illumination whose spectral range lies entirely outside of the passband of the optical filter; acquiring a stopband map of the optical filter using the two-dimensional array of photodetectors while illuminating the optical filter with the stopband illumination; and identifying pinholes of the optical filter as high intensity locations of the stopband map.

Abstract: The disclosure is directed toward driving methods and a driving circuit which are particularly suitable for bi-stable displays. In certain embodiments, methods provide the fastest and most pleasing appearance to the desired image while maintaining the optimal image quality over the life expectancy of an electrophoretic display device.

Abstract: This application is directed to driving methods for electrophoretic displays. The driving methods and waveforms have the advantage that they provide a clean and smooth transition from one image to another image, without flashing or other undesired visual interruptions. The methods also provide faster image transitions. In an embodiment, a method drives a display device from a first image to a second image wherein images of a first color are displayed with a background of a second color, which method comprises driving pixels of the first color directly to the second color before driving pixels of the second color directly to the first color.

Abstract: The present invention is directed to an electrophoretic fluid which comprises uncharged or lightly charged neutral buoyancy particles. The resulting fluid can improve not only image stability but also contrast ratio of a display device, without significantly affecting the switching speed. The present invention is also directed to an electrophoretic display comprising display cells filled with the electrophoretic fluid.

Abstract: An interference filter includes a layers stack comprising a plurality of layers of at least: layers of amorphous hydrogenated silicon with added nitrogen (a-Si:H,N) and layers of one or more dielectric materials, such as SiO2, SiOx, SiOxNy, a dielectric material with a higher refractive index in the range 1.9 to 2.7 inclusive, or so forth. The interference filter is designed to have a passband center wavelength in the range 750-1000 nm inclusive. Added nitrogen in the a-Si:H,N layers provides improved transmission in the passband without a large decrease in refractive index observed in a-Si:H with comparable transmission. Layers of a dielectric material with a higher refractive index in the range 1.9 to 2.7 inclusive provide a smaller angle shift compared with a similar interference filter using SiO2 as the low index layers.

Abstract: In a method of manufacturing a one-dimensionally varying optical filter, a substrate is coated to form a stack of layers of two or more different types. The coating may, for example, employ sputtering, electron-beam evaporation, or thermal evaporation. During the coating, the time-averaged deposition rate is varied along an optical gradient direction by generating reciprocation between a shadow mask and the substrate in a reciprocation direction that is transverse to the optical gradient direction. In some approaches, the shadow mask is periodic with a mask period defined along the direction of reciprocation, and the generated reciprocation has a stroke equal to or greater than the mask period along the direction of reciprocation. The substrate and the shadow mask may also be rotated together as a unit during the coating. Also disclosed are one-dimensionally varying optical filters, such as linear variable filters, made by such methods.

Abstract: An interference filter includes a layers stack comprising a plurality of layers of at least: layers of amorphous hydrogenated silicon with added nitrogen (a-Si:H,N) and layers of one or more dielectric materials, such as SiO2, SiOx, SiOxNy, a dielectric material with a higher refractive index in the range 1.9 to 2.7 inclusive, or so forth. The interference filter is designed to have a passband center wavelength in the range 750-1000 nm inclusive. Layers of a dielectric material with a higher refractive index in the range 1.9 to 2.7 inclusive provide a smaller angle shift compared with a similar interference filter using SiO2 as the low index layers.

Abstract: The disclosure is directed toward driving methods and a driving circuit which are particularly suitable for bi-stable displays. In certain embodiments, methods provide the fastest and most pleasing appearance to the desired image while maintaining the optimal image quality over the life expectancy of an electrophoretic display device.

Abstract: The present invention is directed to an electrophoretic fluid which comprises additive particles. The concentration of the additive particles in the electrophoretic fluid is 2.5% to 25% by weight and the additive particles are not seen at the viewing side during operation of the display. The resulting fluid can improve optical performance of a display device, such as image stability and contrast ratio. The present invention is also directed to an electrophoretic display comprising the electrophoretic fluid.

Abstract: The present invention is directed to electrophoretic displays comprising microcups of a first shape and the microcups of a second shape, wherein each of the microcups of the first shape is surrounded by the microcups of the second shape, and the second shape is 90% or less of the first shape in area. The present electrophoretic displays comprise novel microcup designs, which may reduce the appearance of defects in the display images.

Abstract: The invention relates to waveforms, circuits and methods for driving bistable displays. The invention is directed to a method, comprising in combination: applying, across a bistable display device, a shaking signal comprising a plurality of positive and negative pulses each driven for a first time to disperse partially packed particles; applying, across the device, one or more first driving signals to first pixels of the device for second times that are sufficient to drive the first pixels to one or more reference states; and concurrently with the first driving signals, applying, across the device, one or more second driving signals to second pixels of the device for third times that are shorter than necessary to drive the second pixels to any of the one or more reference states.

Abstract: The present invention is directed to color tuning methods for electrophoretic display devices. For example, a color tuning agent may be added to a composition for forming a display cell structure or a primer layer. Alternatively, a separate color tuning layer may be added to a display device. Further, a color tuning agent may be added to an electrophoretic display fluid. The color tuning methods are useful for adjusting the color temperature of a display device.