1299 results about "Cholesteric liquid crystal" patented technology

Various structures for variable reflectance rearview mirrors and variable transmittance windows are disclosed. One embodiment pertains to the provision of a polarized reflector in a rearview mirror. Another embodiment pertains to the provision of a switchable cholesteric liquid crystal element in a window. Yet another embodiment pertains to the provision of a plurality of apertures in a reflector layer of a rearview mirror where the apertures are sized and positioned in alignment with light emitting areas of a display positioned behind the reflector layer. In another embodiment, a moveable display or mirror element is attached to a rearview mirror housing.

eSheets create a multitude of different products. One embodiment is a projected capacitive touch sensor created by embedding orthogonal arrays of coated metal wires into the surface of a polymer sheet or onto the back of a projector screen. To increase the capacitance of the electrodes or pixels in the sensor, transparent conductive electrodes can be electrically connected to the wire electrodes. Another embodiment is a reflective, energy-efficient display formed by sandwiching a reflective cholesteric liquid crystal (Ch. LC) material between electroded sheet substrates. The eSheet Ch. LCD is pressure sensitive and can be written on using a finger or stylus. The eSheet Ch. LCD can then be read using the wire electrodes in the eSheet LCD.

An electro-active lens is disclosed. The lens includes at least one electro-active cell to provide a lens having at least two focal lengths, the electro-active cell capable of adjusting its focal length based on voltages applied to the electro-active cell. The voltage is supplied by an alternating current source, including a flying capacitor circuit. The electro-active lenses reduce birefringence through the use of a single cholesteric liquid crystal electro-active cell.

An electro-active lens is disclosed. The lens includes at least one electro-active cell to provide a lens having at least two focal lengths, the electro-active cell capable of adjusting its focal length based on voltages applied to the electro-active cell. The voltage is supplied by an alternating current source, including a flying capacitor circuit. The electro-active lenses reduce birefringence through the use of a single cholesteric liquid crystal electro-active cell.

Reflective color filters using layers of cholesteric liquid crystals with two different center wavelengths and bandwidths per layer are stacked in two layers to provide colored light for displays. With a two layer stack circularly polarized light of one handedness can be provided. With a two layer stack circulary unpolarized colored light can be provided. With a broadband polarizing filter overlapping other filters in the stack a black matrix can be provided by reflecting all colors and transmitting no light in the overlapping areas. When broadband reflective cholesteric liquid crystals are used two primary colors can be reflected in the same pixel of a display making reflective layers with two reflective portions per layer possible. Color displays having three linear sub-pixels with three primary colors or with four sub-pixels of white, blue, green, and red in a pixel with two colors in a top row and two colors on a bottom row can are made with two colors per layer in two layer stacks. The pixels in the display are arranged such that multiple adjacent sub-pixels in a layer, or row in a layer, with the same color makes the color filters easier to manufacture. Displays using these reflective color filters may have a reflective polarizer for viewing the display at wide angles without color distortion.

A color liquid crystal display using reflective color filters using layers of cholesteric liquid crystals is disclosed. The reflective color filters have two different center wavelengths and bandwidths per layer and are stacked in two layers to provide colored light for displays. With various numbers of layers in the stack, different polarization levels are provided. The pixels in the display of the invention are arranged such that multiple adjacent sub-pixels in a layer with the same color makes the color filters easier to manufacture.

The present invention features a liquid crystal display device including a printed circuit board, PCB, substrate composed of non-conductive material and having a front surface and having an opposing back surface that contains electrical circuitry and is located near the back of the display device. A liquid crystal display is disposed on the front PCB substrate surface and includes first and second electrode layers and a dispersion layer disposed between the first and second electrode layers. The dispersion layer includes liquid crystal (e.g., cholesteric liquid crystal) dispersed in a polymer matrix. Electrical through-conductors extend between the front substrate surface and the back substrate surface. The through-conductors are in electrical contact with the first and second electrode layers. Drive electronics are disposed on the PCB substrate and are adapted to apply voltage pulses to the first and second electrodes effective to form images on the liquid crystal display. In one aspect the front of the PCB substrate is a non-component surface free of drive electronics. In another aspect, the PCB substrate is the only substrate of the display device. Also featured are methods of making the display device, including forming the display as a transfer film, which forms an electrical connection when the first electrode layer is applied to the PCB substrate. Another method forms the device by printing or coating the display component layers on the PCB substrate.

An identification medium 100 comprises an adhesive layer 102, an ink displaying layer 103, a cholesteric liquid crystal layer 106 including a hologram 107, and a transparent protective layer 108. The ink displaying layer 103 comprises a printed layer 104 formed by printing with an ink which includes cholesteric liquid crystals, and a printed layer 105 formed by an ordinary ink. When the printed layer 104 and the printed layer 105 are observed from the front side, the printed layer 104 and the printed layer 105 are formed so as to have the same color. Thus, when the identification medium is tilted, a visual effect is produced in which a figure formed by the printed layer 105 appears.

A semitransparent display (100), suitable for use with an electronic device (700), is provided. The semitransparent display (100), in one embodiment, includes a cholesteric liquid crystal display layer (101) and a translucent electroluminescent layer (102), such as an organic light emitting diode device. Control circuitry (109) is coupled to each layer, and is configured to selectively actuate each layer. The cholesteric liquid crystal display layer (101) can be operated in any of a planar mode (201), a focal conic mode (202), or a homeotropic mode (203). Segments of the cholesteric liquid crystal display layer (101) can be selectively actuated so as to hide and reveal user actuation targets. Capacitive sensors (621,622) can be included so that the semitransparent display (100) works as a touch sensitive user interface. A user can see an object, such as a hand (105) or stylus, from above the semitransparent display (100) when the hand (105) or stylus is placed beneath the semitransparent display (100).

An electronic writing tablet is composed of one or more layers on which an image is formed and can be selectively erased. One aspect of the invention is a bistable cholesteric writing tablet on which an image is formed while applying writing pressure. The image can be fully erased and new images written on the tablet. In addition, one can selectively erase any or all portions of the written image to restore the original background color. Another aspect of the invention is a multi-color stacked writing tablet in which a color of an image is selected (usually by applying a suitable voltage) while applying writing pressure using an instrument such as an untethered stylus on the surface of the tablet. The writing tablet includes at least two or three stacked layers of bistable cholesteric liquid crystal material. Selected colors can be additively mixed to achieve intermediate colors as desired. The image can be fully erased and new images written on the tablet. In addition, one can selectively erase any or all portions of the written image to restore the original background color.

A writing / drawing tablet utilizing a data capture device such as a pressure sensitive display that can capture data from the resulting image drawn on the device. In general, Bistable Liquid Crystal Displays (BLCD), and in particular, Cholesteric Liquid Crystal Displays (ChLCDs), can be utilized in such a device to create low cost pressure sensitive displays that are efficient power consumers and that can be utilized in a number of unique devices.

A thin holographic optical switch used in a liquid crystal display device contains opposing transparent substrates transparent electrodes between the substrates and a diffraction grating between the electrodes. The diffraction grating contains regions of transparent polymerized photopolymers and cholesteric liquid crystal micro-droplets. Refractive indexes of the photopolymers and liquid crystal are substantially the same when the electrodes have the same potential. The holographic optical switch transmits broadband LED light when the potential difference between the electrodes is zero and is polarization independent. The holographic optical switch diffracts broadband LED light when the potential difference between the electrodes is non-zero and is polarization independent.

One aspect of the invention is a bistable cholesteric writing tablet on which an image is formed by applying a suitable voltage while applying writing pressure, which results in a focal conic texture in a reduced gap region of the active layer while not changing the texture of the unreduced gap region of the active layer (e.g., a written portion being in a focal conic texture on a background in the planar texture). Another aspect of the invention is a multi-color stacked writing tablet in which a color of an image is selected by applying a suitable voltage while applying writing pressure using an instrument such as an untethered stylus on the surface of the tablet. The writing tablet includes at least two or three stacked layers of bistable cholesteric liquid crystal material. Selected colors can be additively mixed to achieve intermediate colors as desired. The image can be erased and new images written on the tablet. Gray scale achieved by varying the applied voltage during writing or the writing pressure in some cases, enables the writing tablet to produce a broad range of colors. The writing device is suitable for many applications such as a toy, sketch pad, erasable signage, tags or a large writing board without the mess of chalk or ink.

The invention features electronic skin including an active layer formed of bistable cholesteric liquid crystal material and articles comprising the skin, the electronic skin having uniform gray scale reflectivity. Also featured is method for producing suitable reduction pulses that will provide a display (e.g., the electronic skin) with uniform gray scale reflectivity. Reduction pulses of narrow width are used to create uniform levels of gray in the electronic skin to overcome display imperfections that cause discontinuity in the gray scale reflectivity.

A computer-controlled system for producing a multi-color image on a substrate using multi-colored cholesteric liquid crystal (CLC) pigment materials made from CLC flakes tuned to predetermined bands of color. An image generator automatically generates an image specifying a pattern over which binder material is to be applied to a substrate by a binder material applicator. A plurality of CLC pigment applicators automatically apply patterns of different-color CLC pigment material to the pattern of binder material, which binds thereto as the binder material dries according to its drying characteristics. An output device is used to automatically return the substrate to a different one of CLC pigment applicators after each application of a pattern of different-color CLC pigment material to the pattern of binder material. The output device automatically repeats the return of the substrate to the CLC pigment applicators until all bands of color in the multi-color image are rendered.

The present invention features a liquid crystal display device including a printed circuit board, PCB, substrate composed of non-conductive material and having a front surface and having an opposing back surface that contains electrical circuitry and is located near the back of the display device. A liquid crystal display is disposed on the front PCB substrate surface and includes first and second electrode layers and a dispersion layer disposed between the first and second electrode layers. The dispersion layer includes liquid crystal (e.g., cholesteric liquid crystal) dispersed in a polymer matrix. Electrical through-conductors extend between the front substrate surface and the back substrate surface. The through-conductors are in electrical contact with the first and second electrode layers. Drive electronics are disposed on the PCB substrate and are adapted to apply voltage pulses to the first and second electrodes effective to form images on the liquid crystal display. In one aspect the front of the PCB substrate is a non-component surface free of drive electronics. In another aspect, the PCB substrate is the only substrate of the display device. Also featured are methods of making the display device, including forming the display as a transfer film, which forms an electrical connection when the first electrode layer is applied to the PCB substrate. Another method forms the device by printing or coating the display component layers on the PCB substrate.

An optical body includes a substrate and a cholesteric liquid crystal layer disposed on the substrate. The cholesteric liquid crystal layer has a non-uniform pitch along a thickness direction of the layer and comprises a crosslinked polymer material that substantially fixes the cholesteric liquid crystal layer. The crosslinking hinders diffusion of cholesteric liquid crystal material within the cholesteric liquid crystal layer. In other methods of making an optical body, a reservoir of chiral material is provided during the process over a first cholesteric liquid crystal layer to diffuse into the layer and provide a non-uniform pitch. Alternatively, two coating compositions can be disposed on a substrate where the material of the first coating composition is not substantially soluble in the second coating composition.

Reflective color filters using layers of cholesteric liquid crystals with two different center wavelengths and bandwidths per layer are stacked in two layers to provide colored light for displays. With a two layer stack circularly polarized light of one handedness can be provided. With a four layer stack unpolarized colored light can be provided. With a broadband polarizing filter overlapping other filters in the stack a black matrix can be provided by reflecting all colors and transmitting no light in the overlapping areas. When broadband reflective cholesteric liquid crystals are used two primary colors can be reflected in the same pixel of a display making reflective layers with two reflective portions per layer possible. Color displays having three linear sub-pixels with three primary colors or with four sub-pixels of white, blue, green, and red in a pixel with two colors in a top row and two colors on a bottom row can are made with two colors per layer in two layer stacks. The pixels in the display are arranged such that multiple adjacent sub-pixels in a layer, or row in a layer, with the same color makes the color filters easier to manufacture. Displays using these reflective color filters may have a reflective polarizer for viewing the display at wide angles without color distortion. A method of producing cholesteric liquid crystal color filters by polymerizing different portions of cholesteric liquid crystal mixtures at different temperatures and radiations to obtain different central wavelengths and bandwidths of reflection. By masking parts of a layer several portions with different colors are polymerized in a single layer. Further, with radiation which is attenuated in the cholesteric liquid crystal material stacks of different portions reflecting different colors in the same layer are made. Further the cholesteric liquid crystals are polymerized to have other optical properties in the stack such as quarter wave plates and broad band polarizers such that entire optical devices can be made in one layer of cholesteric liquid crystal material making the devices smaller, lighter, more robust, reliable, and easier to make by eliminating gluing and alignment problems. With overlapping reflective cholesteric liquid crystal which together reflect all light stacks with automatic black matrixes built into the layer are made saving light from being blocked by conventional black matrix light absorbing layers in display devices.

The present invention enables a user of a portable electronic communications device such as a cell phone to view information on a larger remote reflective cholesteric display. The portable communications device may connect with the remote display by wire or wirelessly. The remote display is separate from the portable communications device but can interact with it. The remote display receives and / or receives and sends information relative to the portable communications device. This information can include e-mail text and graphics. The remote display, being a bistable cholesteric liquid crystal display, possesses low power requirements unmatched by other display technologies. Moreover, the remote display can serve a dual purpose of displaying images and collecting solar power whereby a photovoltaic material behind the display generates electrical energy from light incident on the cholesteric liquid crystal material, which may be used not only to power the remote display but also the portable communications device. This may result in a completely self-powered remote display and associated portable communications device. The solar cell itself can be a component of the display. A display having only a single substrate may employ the solar cell as the substrate. A dispersion layer comprised of cholesteric liquid crystal material dispersed in a polymer matrix, may be disposed over the substrate. Another aspect of the invention features a drapable remote bistable cholesteric display.

One aspect of the invention is a bistable cholesteric writing tablet on which an image is formed by applying a suitable voltage while applying writing pressure, which results in a focal conic texture in a reduced gap region of the active layer while not changing the texture of the unreduced gap region of the active layer (e.g., a written portion being in a focal conic texture on a background in the planar texture). Another aspect of the invention is a multi-color stacked writing tablet in which a color of an image is selected by applying a suitable voltage while applying writing pressure using an instrument such as an untethered stylus on the surface of the tablet. The writing tablet includes at least two or three stacked layers of bistable cholesteric liquid crystal material. Selected colors can be additively mixed to achieve intermediate colors as desired. The image can be erased and new images written on the tablet. Gray scale achieved by varying the applied voltage during writing or the writing pressure in some cases, enables the writing tablet to produce a broad range of colors. The writing device is suitable for many applications such as a toy, sketch pad, erasable signage, tags or a large writing board without the mess of chalk or ink.

A thin holographic optical switch used in a liquid crystal display device contains opposing transparent substrates transparent electrodes between the substrates and a diffraction grating between the electrodes. The diffraction grating contains regions of transparent polymerized photopolymers and cholesteric liquid crystal micro-droplets. Refractive indexes of the photopolymers and liquid crystal are substantially the same when the electrodes have the same potential. The holographic optical switch transmits broadband LED light when the potential difference between the electrodes is zero and is polarization independent. The holographic optical switch diffracts broadband LED light when the potential difference between the electrodes is non-zero and is polarization independent.

A liquid crystal device for writing, inputting, and displaying information comprises: a first substrate, a second substrate, and a cell structure sandwiched between the two substrates, defining a plurality of isolated subcells. Means for applying an electric field to drive states of the cholesteric liquid crystal in the subcells is coupled to the electrodes. An electromagnetic sensitive panel is positioned proximately under the surface of the second substrate for receiving an electronic / magnetic signal transmitted by a writing tool. In use, when the tip of the writing tool is forced again and moved around the surface of the first substrate, a true track of the movement of the tip is directly shown on the writing surface, while information of the movement of the tip of the writing tool is sensed by the electromagnetic sensitive panel simultaneously.

The present invention enables a user of a portable electronic communications device such as a cell phone to view information on a larger remote reflective cholesteric display. The portable communications device may connect with the remote display by wire or wirelessly. The remote display is separate from the portable communications device but can interact with it. The remote display receives and / or receives and sends information relative to the portable communications device. This information can include e-mail text and graphics. The remote display, being a bistable cholesteric liquid crystal display, possesses low power requirements unmatched by other display technologies. Moreover, the remote display can serve a dual purpose of displaying images and collecting solar power whereby a photovoltaic material behind the display generates electrical energy from light incident on the cholesteric liquid crystal material, which may be used not only to power the remote display but also the portable communications device. This may result in a completely self-powered remote display and associated portable communications device. The solar cell itself can be a component of the display. A display having only a single substrate may employ the solar cell as the substrate. A dispersion layer comprised of cholesteric liquid crystal material dispersed in a polymer matrix, may be disposed over the substrate. Another aspect of the invention features a drapable remote bistable cholesteric display.

Disclosed is an infrared light reflecting plate for reflecting infrared light, which comprises a substrate and at least four light-reflective layers X1, X2, X3 and X4 each of which is formed of a fixed cholesteric liquid-crystal phase. The reflection center wavelength of the light-reflective layers X1 and X2 is the same and is λ1 (nm), the two layers reflect circularly-polarized light in opposite directions, and the reflection center wavelength λ1 (nm) falls within a range of from 1010 to 1070 nm, and the reflection center wavelength of the light-reflective layers X3 and X4 is the same and is λ2 (nm), the two layers reflect circularly-polarized light in opposite directions, and the reflection center wavelength λ2 (nm) falls within a range of from 1190 to 1290 nm.

An electronic writing tablet is composed of one or more layers on which an image is formed and can be selectively erased. One aspect of the invention is a bistable cholesteric writing tablet on which an image is formed while applying writing pressure. The image can be fully erased and new images written on the tablet. In addition, one can selectively erase any or all portions of the written image to restore the original background color. Another aspect of the invention is a multi-color stacked writing tablet in which a color of an image is selected (usually by applying a suitable voltage) while applying writing pressure using an instrument such as an untethered stylus on the surface of the tablet. The writing tablet includes at least two or three stacked layers of bistable cholesteric liquid crystal material. Selected colors can be additively mixed to achieve intermediate colors as desired. The image can be fully erased and new images written on the tablet. In addition, one can selectively erase any or all portions of the written image to restore the original background color.

A a chiral fiber grating mimicking a cholesteric liquid crystal structure to achieve fiber Bragg grating properties, is provided. The chiral fiber grating includes a first and a second helical structures disposed along its central longitudinal axis, where the second helical structure is identical in orientation to the first helical structure but is shifted by one half of the structure's pitch forward. In another embodiment of the invention, only a single helical structure is disposed along the fiber to create an optically resonant chiral fiber.

A polychromic ink composition depending on viewing angle comprises 0.5 to 40% by weight of cholesteric liquid crystal polymer particles whose maximum particle diameter is 1 to 200 mum, 1.0 to 30.0% by weight of binder resins, 0.05 to 20% by weight of pigments with a deep-colored coloring matter whose average particle diameter is 0.01 to 0.5 mum, 0.01 to 5.0% by weight of a shear-thinning property imparting agent, and water with respect to the total amount of the ink composition.

In a display element in which three or more display layers for displaying mutually different color lights are stacked within one pixel and which controls display states of the plural display layers by applying a voltage from the outside of the plural display layers, eight colors-white, black, blue, green, red, cyan, magenta, and yellow-can be displayed within one pixel. Display layers having cholesteric liquid crystals selectively reflecting blue, green, and red lights are stacked between a pair of substrates, and a light absorption layer is formed on the back of the substrate of a non-display side. Threshold voltages of orientation change of the display layers are mutually changed, and a threshold voltage Vpf90(A) of change from a planer state to a focal conic state of the display layer having the highest threshold voltage is made higher than a threshold voltage Vfh90(C) of change from a focal conic state to a homeotropic state of the display layer having the lowest threshold voltage.

Methods of making an optical body are disclosed. A method includes the steps of coating a mixture including a first cholesteric liquid crystal polymer, a second cholesteric liquid crystal monomer, a second cholesteric liquid crystal polymer formed from a portion of the second cholesteric liquid crystal monomer, and a solvent on a substrate. The first cholesteric liquid crystal polymer is different than the second cholesteric liquid crystal polymer. Then, forming from the mixture an optical body including a first layer, a second layer, and a third layer disposed between the first and second layer. The first layer includes a majority of the first cholesteric liquid crystal polymer. The second layer includes a majority of a second cholesteric liquid crystal monomer. The third layer includes the second cholesteric liquid crystal polymer.