Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
1999-05-27
2001-12-04
Sikes, William L. (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S147000
Reexamination Certificate
active
06327013
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a liquid crystal device. Such a device may be used, for example, in liquid crystal displays based on diffraction using nematic liquid crystal (NLC), ferroelectric liquid crystal (FLC) and antiferroelectric liquid crystal (AFLC).
DISCUSSION OF THE RELATED ART
Liquid crystal devices having multi-layer electrode structures on one substrate are known. For example, U.S. Pat. Nos. 5,126,865, 5,321,535, 5,576,863 and 5,610,739 disclose liquid crystal displays in which each picture element (pixel) is divided into subpixels in order to provide grey scale capability. The addressing arrangements in these known devices use multilayer electrode arrangements to control addressing of the subpixels so as to achieve grey levels,
U.S. Pat. No. 5,608,556 discloses a liquid crystal display intended to provide a wider viewing angle. A multilayer electrode arrangement on one substrate provides a radial electric field component to the normally perpendicular electric field so as to cause the switched orientation of the liquid crystal molecules to vary across the pixel.
EP 0 749 029 discloses a liquid crystal display in which the electric field is generally parallel to the substrates. The electric field is generated between a common electrode and a pixel electrode, both of which are disposed on the lower substrate of the device.
Diffraction based devices using phase-only grating techniques are disclosed in GB 2 313 920 and EP 0 811 872, Addressing arrangements for such devices are disclosed in British patent applications numbers 9702076.2, 9709467.6, 9712134.7 and 9716112.9. Such devices require the use of high resolution electrodes and are suitable for use in projection displays providing high brightness and good contrast ratio.
U.S. Pat. No. 5,182,665 discloses a liquid crystal device which comprises an electrode layer consisting of a pair of inter-digitated electrodes. It is possible to define a diffraction grating in the liquid crystal layer by applying voltages of opposite sign to the two inter-digitated electrodes. In another embodiment of U.S. Pat. No. 5,182,665, the electrode layer consists of an upper electrode layer having a comb-shape disposed over a continuous lower electrode layer, and it is possible to define a diffraction grating in the liquid crystal layer by applying voltages of opposite sign to the two electrode layers.
WO 89/12033 is directed to increasing the physical strength of a conductive film, without adversely affecting the conductivity or optical properties of the film. It discloses a transparent conductive coating containing a transparent insulating layer and a transparent conductive layer, with the two layers having substantially the same refractive index. The transparent conductive coating can be set to have any desired thickness and any desired electrical conductivity. The optical properties of the coating will be determined by the combined thickness of the two layers, provided that the refractive indices of the two layers are equal.
EP-A-0 823 654 discloses a reflective liquid crystal device in which the scanning electrodes on the lower substrate are metallic and are provided with a reflective and diffusive upper surface.
U.S. Pat. No. 5,737,050 is directed to reducing scattering of light substrates of a liquid crystal display device, in order to prevent cross-talk between adjacent pixels. It discloses an “anti-reflection counter electrode”, which consists of a dielectric film disposed on an ITO layer. The ITO layer acts as the electrode, and the dielectric film reduces the reflection that occurs at the interface between the substrate and the electrode. It also discloses an anti-reflection counter electrode which consists of a dielectric film, an ITO layer, and a second dielectric film. Each of the dielectric films consists of three dielectric layers having, respectively, a low refractive index, a high refractive index, and a low refractive index.
SUMMARY OF THE INVENTION
According to a fist aspect of the invention, there is provided a liquid crystal device comprising first and second substrates, a layer of liquid crystal disposed between the first and second substrates, and a plurality of picture elements, each of which comprises a first electrode disposed on the first substrate, a plurality of laterally spaced second electrodes electrically insulated from and disposed above the first electrode relative to the substrate, and a third electrode disposed on the second substrate; wherein at least one of the second electrodes is electrically connected to the third electrode.
The second electrodes may be electrically connected together
According to a second aspect of the invention, there is provided a liquid crystal device comprising first and second substrates, a layer of liquid crystal disposed between the first and second substrates, and a plurality of picture elements, each of which comprises a first electrode disposed on the first substrate, a plurality of laterally spaced second electrodes electrically insulated from and disposed above the first electrode relative to the substrate, and a third electrode disposed on the second substrate; wherein the second electrodes in at least one picture element are electrically connected to earth potential.
According to a third aspect of the present invention there is provided a liquid crystal device comprising first and second substrates, a layer of liquid crystal disposed between the first and second substrates, and a plurality of picture elements, each of which comprises a first electrode disposed on the first substrate, a plurality of laterally spaced second electrodes electrically insulated from and disposed above the first electrode relative to the substrate, and a third electrode disposed on the second substrate; wherein the picture elements are arranged in a regular array; and wherein the device further comprises addressing means for address the second electrodes corresponding to a row, or column, of picture elements independently from the second electrodes corresponding to other rows, or columns, of picture elements.
The second electrodes may comprise striped substantially parallel electrodes. The second electrodes may be substantially evenly spaced apart.
The picture elements may be arranged as a regular array.
Each third electrode may extend along and be common to a column of picture elements and each first electrode may extend along and be common to a row of picture elements to form a passive matrix addressing arrangement. The second electrodes may extend substantially parallel to the first or third electrodes. Alternatively, the second electrodes may extend at substantially 45° to the first electrodes.
The third electrode may be common to all of the picture elements and each of the first electrodes may comprise a picture element electrode connected to an active non-linear device to form an active matrix addressing arrangement.
The pixels may be arranged in rows and columns and the second electrodes may extend in substantially the row or column direction. Alternatively, the second electrodes may extend at substantially 45° to the row direction.
A fourth aspect of the present invention provides a liquid crystal device comprising first and second substrates, a layer of liquid crystal disposed between the first and second substrates, and a plurality of picture elements, each of which comprises a first electrode disposed on the first substrate, a second electrode electrically insulated from and disposed above the first electrode relative to the substrate, and a third electrode disposed on the second substrate; wherein the second electrode extends over a central area of the pixel and a plurality of apertures are provided in the second electrode; wherein the second electrode is electrically connected to the third electrode.
A fifth aspect of the present invention provides a liquid crystal device comprising first and second substrates, a layer of liquid crystal disposed between the first and second substrates, and a plurality of picture elements, each of which c
Anderson Duncan James
Mayhew Nicholas
Robinson Michael Geraint
Slack Jason
Todd Karen Emma
Qi Mike
Renner Otto Boisselle & Sklar
Sharp Kabushiki Kaisha
Sikes William L.
LandOfFree
Liquid crystal device in which an electric field within the... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Liquid crystal device in which an electric field within the..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Liquid crystal device in which an electric field within the... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2565422