JP2005078080A - Multiple view display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multiple view display (e.g. a dual view display) for displaying unrelated images in different viewing regions. <P>SOLUTION: The display is equipped with a liquid crystal display device (20-28) having pixels (101 102) with asymmetric viewing angle characteristics. The display is equipped with a driving device (29) to drive pixels to display a first image in a first viewing direction and to display a second image in a second different viewing direction. The pixel (101) to display the first image appears dark in the second direction, while the pixel (102) to display the second image appears dark in the first direction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a multiple view display. Such a display can be used to display two or more views that include images that are substantially different from each other. Such a display allows different viewers to see different images that may be independent of each other.

  FIG. 1 of the accompanying drawings shows the concept of a multiple view display, which in this embodiment includes a dual view display. Viewers 1 and 2 located in viewing areas 1 and 2 see dual view display 10. Display 10 has a separate viewing area where substantially different images can be displayed. For example, while the viewer 2 is reading a map, the viewer 1 can watch a movie. Such an example can be applied, for example, to a display for use in a car where a passenger is watching a movie simultaneously while the driver is watching navigation information.

  FIG. 2 of the accompanying drawings shows another example of use of the dual view display 10. In this case, the display is attached to the plane of the desk or counter 11 so that the viewers 1 and 2 on both sides of the desk or counter 11 can see different images. Similarly, FIG. 3 shows a horizontally oriented multi-view display that in this case displays four unrelated images to viewers 1-4 on the four sides of the display.

  The viewing angle characteristic of the twisted nematic (TN) liquid crystal (LC) mode is well known, and the viewing angle characteristic of such a liquid crystal display (LCD) is disclosed in Non-Patent Document 1. These characteristics are relatively nearly uniform in the horizontal viewing angle direction, but are asymmetric in the vertical viewing angle direction. Techniques are known for optimizing the viewing angle characteristics of LCDs to allow the same image to be viewed from a wide range of angles.

    A multiple-view video display is disclosed in Japanese Patent Application Laid-Open No. 2005-228561. In this example, lenticular lenses are used to generate different viewing areas.

  The directional viewing characteristics of TN and guest-host (GN) LCDs are disclosed in US Pat. These documents disclose spatially multiplexing two images of an LCD with a different arrangement of pixels for displaying one image than pixels for displaying another image. These documents refer to autostereoscopic displays or stereoscopic displays that display related images to provide a 3D display.

  Patent document 6 discloses a dual layer autostereoscopic display. One layer displays a spatially multiplexed image behind another layer, which serves as a direction control layer that directs the image to different viewing areas for autostereoscopic viewing.

  These documents disclose a configuration in which pixels for displaying one image are arranged in the same manner as pixels for displaying another image. However, the pixels for one image are substantially rotated, or are substantially mirror images, for the other image being displayed.

  Non-Patent Document 3 discloses a configuration that covers an image panel that displays a left-eye image and a right-eye image in which passive spatially patterned liquid crystal layers are spatially multiplexed. This passive layer includes a twisted nematic liquid crystal region and a Fredericks mode liquid crystal region that rotates the polarization of light for one view and does not rotate the light change for another view. The image can be viewed in an autostereoscopic manner without view assistance or without the use of polarizing glass in a stereoscopic manner.

  U.S. Patent No. 6,057,031 discloses a stereoscopic display including stacked guest-host liquid crystal device pairs. Each of the devices displays a respective view, and the device array is oriented perpendicular to each other. Thus, the left and right views are polarized perpendicular to each other, and polarizing glass is used to view the display in three dimensions.

  Patent Document 7 discloses a configuration using a lenticular screen for providing two or more 2D or 3D images.

  Patent Document 8 displays a left image and a right image in which the display screen is spatially multiplexed, and a plurality of additional devices in front of the display screen controls the visibility of the image by the left and right eyes of the observer Is disclosed.

  Patent Document 9 discloses a stereoscopic display that uses electrical switching between two liquid crystal barriers to move the effective position of the parallax barrier.

  U.S. Patent No. 6,057,031 uses a twisted nematic liquid crystal mode that optimally displays an image from a panel to two observers by controlling the direction of the maximum contrast ratio in the middle between the two viewing positions. Is disclosed.

  Patent Document 11 discloses the use of a twisted nematic liquid crystal mode. By changing the voltage range used, the viewing angle range is wide enough to produce an image with a distinguishable contrast ratio, so that all viewers can see the image, and only normal incidence viewers You can switch between viewing private mode where you can see some images.

  Patent document 12 discloses the use of an LC layer that prevents the image from the in-vehicle TV from reaching the driver by shifting the region of maximum contrast ratio towards the passenger's viewing position.

  Patent Document 13 and Patent Document 14 disclose the use of an LC layer that prevents the image from the in-vehicle TV from reaching the driver by switching the LC layer so that it appears black to the driver.

  U.S. Patent No. 6,057,032 discloses using pixels with different viewing angle characteristics to display different images in different viewing angle ranges from a display. This also discloses changing the viewing characteristics of the pixel by applying a voltage.

  Patent Document 16 discloses the use of a voltage according to the optical twist of the liquid crystal. Changing the voltage range used changes the viewing angle so that one image can be seen in one viewing angle range and the second image from one display can be seen in another viewing angle range To do.

  U.S. Patent No. 6,057,033 discloses the use of dual domain pixels that can be electrically controlled separately so that one domain can display an image and another domain can display a second image. Different images can be displayed in different viewing angle ranges due to different tilts or twists of the liquid crystal between each domain.

U.S. Patent No. 6,057,034 discloses the use of at least two different specific viewing angle pixels that are interlaced to produce a multi-view display. There may be more than one display layer.
JP-A-6-236152 Japanese Patent Laid-Open No. 2-146087 JP 60-211141 A JP 60-21114 A Japanese Patent Application Laid-Open No. 60-211428 JP-A-8-101367 US Pat. No. 6,424,323 European Patent Application No. 1250013 Japanese Patent Laid-Open No. 9-43540 International Publication No. 95/27973 Pamphlet WO99 / 45527 pamphlet US Pat. No. 5,059,957 US Pat. No. 5,562,065 US Patent Application Publication No. 2000/0007227 US Pat. No. 5,936,596 US Pat. No. 6,593,904 US Pat. No. 6,724,450 International Publication No. 2004/036286 Pamphlet P. Yeh and C.M. Gu, “Optics of Liquid Crystal Displays”, John Wiley and Sons Inc. 1999, Chapter 9 Okada et al. , “Possibility of Stereoscopic Displays by Using a Viewing Angle Dependence of Twisted Nematic Liquid Crystal 45, IEET Transact 45”, IEET Transact 45. Chen et al. , "Simple Multimode Stereoscopic Liquid Crystal Display", Japan Journal of Applied Physics, 1997, Vol. 36, L1685-L1688.

  Therefore, it is desired that different images be seen in different directions with a relatively high contrast ratio.

  The concept of “different configuration” when applied to a liquid crystal display (LCD) pixel (picture element) is defined to mean that the pixel is different with respect to any of the following, or any combination of: . Pretilt of one or both of the liquid crystal substrate interface; bulk liquid crystal director alignment; liquid crystal thickness; director twist; liquid crystal material doping with chiral additive; dye or polymer material; polarization transmission axis alignment; azimuth and / or zenith angle anchor Strength; retardation size and / or optical axis alignment; compensation layer effect; liquid crystal material; drive system. However, the case where a certain pixel is a rotated image or a mirror image of another pixel is excluded.

  The concept of “different LC modes” when applied to liquid crystal display pixels is defined to mean that the pixels are different with respect to any of the following, or any combination of: Pre-tilt of one or both of the liquid crystal substrate interface; bulk liquid crystal director alignment; liquid crystal thickness; director twist; azimuth angle and / or zenith angle anchor strength; polarization transmission axis alignment when the polarizer is placed in a liquid crystal cell; Retardation or compensation effect when the compensator is placed in a liquid crystal cell; liquid crystal material; doping of a liquid crystal material with a chiral additive; dye or polymer material. However, the case where a certain pixel is a rotated image or a mirror image of another pixel is excluded.

  According to the first aspect of the present invention, at least one liquid crystal display device including a plurality of pixels having asymmetric viewing angle characteristics, a first image in a first viewing direction, and a first view And a driving device that drives pixels to display a second image in a second viewing direction different from the viewing direction, and the driving device darkens the pixels that display the first image in the second direction. A multi-view display is provided, characterized by cooperating with at least one display device so that the pixels that appear and display the second image appear dark in the first direction.

  The pixels displaying the first image and the second image may appear to be maximally dark in the second direction and the first direction, respectively. The intensity of light supplied in the second direction and the first direction by the pixels that respectively display the first image and the second image is such that the pixels that display the first image and the second image May be smaller than X% of the maximum intensity of light that can be supplied in each of the second direction and the second direction. Here, X is a real number smaller than 20. X may be equal to 10. Alternatively, X may be equal to 3.5. Further alternatively, X may be equal to 1.

  The first image and the second image may be independent of each other.

  The first direction and the second direction may be in a plane that is perpendicular to the display surface of the at least one device and includes the direction of maximum viewing angle asymmetry. The first direction and the second direction may be on both sides of a perpendicular to the display surface. The first direction and the second direction may be substantially symmetric with respect to the normal, or alternatively may be asymmetric with respect to the normal.

  The pixels displaying the first image are configured to provide a first contrast ratio in the first direction and provide a contrast substantially equal to 1 in the second direction to display the second image. The pixel to be configured may provide a second contrast ratio in the second direction and provide a contrast substantially equal to 1 in the first direction.

  The angle between the first direction and the second direction may be substantially greater than or equal to 10 °.

  At least one device may include a set of pixels, and each set of pixels may be the same color or a different color than the other set of pixels. At least one device may include liquid crystal layers having different thicknesses in different color pixels. The at least one device may include a patterned retarder in which different retardation regions are optically arranged for different color pixels. Different retardation regions may contain different color pigments to function as color filters.

  At least one device may be a transmissive mode device.

  The at least one display device may have an asymmetric liquid crystal mode having a uniform alignment and an asymmetric viewing angle characteristic, and the driving device includes a first driving method for displaying the first image, a second It may be configured to drive at least one device with a second driving method different from the first driving method for displaying an image.

  The first driving method and the second driving method may include a first voltage range and a second voltage range that are different from each other.

  The liquid crystal mode may be any one of twist nematic, hybrid alignment nematic, and twist vertical alignment nematic.

  The first view and the second view may be spatially multiplexed on at least one device. The at least one display device may include a liquid crystal layer and a uniform retarder disposed between the uniform input polarizer and the output polarizer. The retarder has an optical axis oriented substantially at 45 ° with respect to one adjacent transmission axis of the polarizing plate and substantially at 67 ° with respect to the normal of the retarder plane in the plane of the retarder. You may have. The retarder may have a retardation of substantially 494 nm. The at least one device comprises a patterned polarizer having a first region and a second region for each of the first view and the second view, wherein the transmission axis of the first region is a second It may be different from the transmission axis of the region. The transmission axis of the first region may be substantially orthogonal to the transmission axis of the second region.

  At least one device may include a patterned retarder. The patterned retarder may be switchable to substantially zero retardation for single view mode operation.

  At least one device may include a parallax barrier.

  The first view and the second view may be temporally multiplexed in at least one device. At least one device may include a switchable retarder. The retardation of the retarder may be switchable between odd and even half-wavelengths of visible light.

  The at least one device includes a first pixel having a first configuration having a first asymmetric viewing angle characteristic, and a second asymmetric viewing oriented differently from the first asymmetric viewing angle characteristic. A second pixel having an angular characteristic and having a second configuration different from the first configuration, wherein the driving device includes a first pixel for displaying the first image, a second pixel, It may be configured to drive the second pixel for displaying an image.

  The first image and the second image may be viewed in a third viewing direction between the first direction and the second direction.

  The first pixels may be spatially dispersed in the second pixels.

  The first asymmetric viewing characteristic and the second asymmetric viewing characteristic may be oriented in substantially opposite directions.

  The first pixel and the second pixel may have a first liquid crystal mode and a second liquid crystal mode that are different from each other. At least one of the first mode and the second mode may be any of twist nematic, hybrid alignment nematic, twist vertical alignment nematic, Frederix, vertical alignment nematic, and pi-cell. The first pixel and the second pixel may have different liquid crystal directors in the absence of an applied electric field. Different twists may have different sizes. Different twists may have different twist effects. One of the different twists may be 0 °.

  The first pixel and the second pixel may have different liquid crystal directors at at least one liquid crystal substrate interface. Different pretilts may have different sizes. Different pretilts may have different directors.

  The first pixel and the second pixel may have different liquid crystal director alignments. The first pixel and the second pixel may have different surface anchor strengths at at least one liquid crystal substrate interface.

  The first pixel and the second pixel may have different liquid crystal materials.

  At least one of the first pixel and the second pixel may have a liquid crystal material including at least one of a chiral dopant, a polymer network, and a dye.

  The first pixel and the second pixel may have liquid crystal layers with different thicknesses.

  The first pixel may have a polarizer whose transmission axis is oriented at a first angle with respect to the liquid crystal optical axis of the first pixel, and the second pixel has a transmission axis that is the second pixel. The liquid crystal optical axis may have a second polarizer that faces a second angle different from the first angle.

  The first pixel and the second pixel may have a first retarder and a second retarder having different retardations.

  The first pixel and the second pixel may have a first compensation layer and a second compensation layer that provide different compensation effects.

  The driving device may be configured to drive the first pixel and the second pixel in different voltage ranges.

  At least one device may include a parallax barrier.

  The display may include additional liquid crystal devices that can be displayed via the devices described above and are configured to operate in time sequence.

  The at least one device includes a first liquid crystal device having a first asymmetric liquid crystal mode with a first asymmetric viewing characteristic and a second asymmetric viewing oriented differently from the first asymmetric viewing characteristic. And a second liquid crystal device having a characteristic second asymmetric liquid crystal mode, wherein the driving device drives the first device in a first driving method for displaying the first image, and the second image is displayed. The second device may be driven by the second driving method for displaying the image.

  The first driving method and the second driving method may include a first voltage range and a second voltage range, respectively. The first voltage range and the second voltage range may be substantially the same.

  The second device may be viewed via the first device. The second device may be disposed between the first device and the backlight.

  The first device and the second device may be substantially parallel to each other.

  Each of the first device and the second device may have a uniform arrangement.

  Each of the first device and the second device may be a transmissive mode device.

  The first liquid crystal mode and the second liquid crystal mode may be the same type.

  The first asymmetric viewing characteristic and the second asymmetric viewing characteristic may be oriented in substantially opposite directions.

  The first device and the second device may have an array oriented in substantially opposite directions.

  At least one of the first liquid crystal mode and the second liquid crystal mode may be any of twist nematic, hybrid alignment nematic, and twist vertical alignment nematic.

  Each of the first device and the second device may include a set of pixels of different colors. One of the first device and the second device may include a set of red, green, and blue pixels, and the other of the first device and the second device may include a set of cyan, magenta, and yellow pixels. May be included. The first device and the second device may include color filter stripes extending substantially parallel to a plane including the first direction and the second direction.

  The display may include a multi-color time series backlight, and the driving device may be configured to drive the first device and the second device in a color time series.

  The driving apparatus may be configured to supply temporally multiplexed images to the first device and the second device and to control the direction-switchable backlight synchronously. Each of the first device and the second device may include a spatial phase modulator.

  The display may include a switchable light scatterer that is switchable between a substantially non-scattering state for the multiple view mode of the display and a scattering mode for the single view mode of the display.

  According to a second aspect of the present invention, a liquid crystal display device having an asymmetric liquid crystal mode having a uniform alignment and asymmetric viewing angle characteristics, and a first image for displaying a first image in a first viewing direction. A driving apparatus that drives the device in a second driving method different from the first driving method in order to display the second image in a second direction different from the first direction. A multi-view display is provided.

  According to the third aspect of the present invention, the first pixel having the first configuration having the first asymmetric viewing angle characteristic is different from the first asymmetric viewing angle characteristic. A liquid crystal device comprising a second pixel having a second configuration different from the first configuration, having an asymmetric viewing angle characteristic of two, and for displaying a first image in a first viewing direction A multi-view display is provided comprising: a driving device for driving the first pixel and driving the second pixel to display a second image in a second viewing direction different from the first direction. The

  According to a fourth aspect of the present invention, a first pixel having a first configuration with a first asymmetric viewing angle characteristic, and a second pixel having a second configuration different from the first configuration, A liquid crystal device including: a first pixel for driving the first pixel to display the first image in the first viewing direction and the second viewing direction; and displaying the second image in the second viewing direction And a driving device for driving the second pixel to provide a multi-view display.

  According to the fifth aspect of the present invention, the first liquid crystal device having the first asymmetric liquid crystal mode with the first asymmetric viewing angle characteristic is directed to be different from the first asymmetric viewing angle characteristic. A second liquid crystal display device having a second asymmetric liquid crystal mode with a second asymmetric viewing angle characteristic, and a first driving method for displaying a first image in the first viewing direction. And a driving device that drives the second device in the second driving method in order to display the second image in a second viewing direction different from the first viewing direction. A multi-view display is provided.

  Accordingly, it is possible to provide a multiple view display in which different images can be seen in different directions with a relatively high contrast ratio. This improves the quality of the displayed image.

  According to the present invention, it is possible to provide a multiple view display in which different images can be seen in different directions with a relatively high contrast ratio.

  The invention is further illustrated by way of example with reference to the accompanying drawings.

  FIG. 4 shows a dual thin film transistor for directing two viewable, unrelated images in viewing regions 1 and 2, respectively, to viewers 1 and 2 as shown in FIGS. (TFT) Active matrix LCD. The display includes a front linear polarizer 20 that is attached to the outer surface of the substrate 21 or formed on the outer surface of the substrate 21. The substrate 21 may be made of glass or any suitable transparent non-birefringent material that is sufficiently stable. The substrate 21 has a transparent electrode made of, for example, indium tin oxide (ITO) on its inner surface. The electrode 22 functions as a counter electrode for the active matrix and uniformly covers the entire active area of the display 10. An alignment surface, such as an alignment layer 23 made of rubbed polyimide, is formed on the electrode 22 and is rubbed uniformly to have the same uniform alignment direction throughout the active area of the display 10.

  The second substrate 27 has a rear linear polarizer 28 and a TFT / electrode layer 26. The electrode layer 26 is patterned to define pixels (picture elements). Such TFTs and electrode arrangements are known and will not be further described. For example, an array surface such as an array layer 25 made of rubbing polyimide is formed on the layer 26. The alignment layer 25 also provides a uniform alignment direction across the entire active area of the display 10.

  The substrates 21 and 27 are formed to have layers 22, 23, 25, and 26. The alignment layer 23 and the alignment layer 25 are aligned so as to face each other, and a liquid crystal layer 24 having a liquid crystal cell therebetween is defined. To do. The liquid crystal layer 24 is, for example, a nematic liquid crystal containing ZLI4792 available from Merck UK. The polarizers 20 and 28 may be formed or provided before or after the liquid crystal cell is formed. Layer 26 includes or is connected to a drive device, indicated by reference numeral 29, to provide an appropriate signal for addressing individual pixels with a voltage defining gray scale. . The device 29 may form all or part of the external components for providing the first and second drive schemes for the first and second images to be displayed. Alternatively, the device 29 can be integrated on the panel.

  FIG. 5 shows the polarizers 20 and 28 and the layers 23 to 25 in an exploded view. FIG. 5 also shows the vertical and horizontal orientation of the display 10 as shown in FIG. The vertical upper reference direction is regarded as 0 °, and the horizontal perpendicular direction is regarded as 90 °. The different directions shown for the components shown in FIG. 5 are referenced to the upper vertical 0 ° direction.

  The front polarizer 20 has a transmission axis 30 oriented at an angle of + 90 ° with respect to the upper vertical. The alignment layer 23 has a uniform alignment direction 33 oriented at an angle of −45 ° with respect to the upper vertical direction. The alignment layer 25 has a uniform alignment direction 35 oriented at an angle of + 45 ° with respect to the upper vertical direction. The polarizer 28 has a transmission axis 38 that is oriented at 180 ° with respect to the upper vertical orientation. Therefore, for the normally white mode operation of the display 10 shown, the transmission axes of the polarizers 20 and 28 are orthogonal to each other. Similarly, the arrangement directions 33 and 35 are orthogonal to each other. In the absence of an applied voltage across the pixel, the liquid crystal layer 20 has a 90 ° twist so that incident light polarized by the back polarizer 28 has a polarization direction rotated by the layer 24 and passes through the polarizer 20. Are arranged in

  If a sufficiently large electric field is applied across the pixel, the directors of the liquid crystal molecules at that pixel are aligned substantially perpendicular to the surface of the layer 24 and will slightly affect the polarization of light passing through the display. Or no effect. Thus, the light passed by the rear polarizer is substantially extinguished by the front polarizer 20, and the pixel appears to be maximally dark or black. For an intermediate applied field, the polarization of light from polarizer 28 is rotated by different amounts to provide a plurality of gray levels that constitute a gray scale having black and white levels. 20 is analyzed.

  FIG. 6 shows a constant ratio variation at different viewing angles of the display 10 shown in FIGS. The display 10 is substantially rotated through 90 ° compared to the general orientation of a TN LCD so that the asymmetric viewing angle direction is substantially horizontal. In this example, the display is configured for viewing at -30 ° and + 30 ° on either side in the horizontal plane of the display normal.

  The viewing angle characteristics of the display 10 are shown in FIG. 7 with respect to enhanced viewing angles of −30 ° and + 30 °. The display is of a type where discrete gray levels 0-255 are addressable, and FIG. 7 is intended to provide a substantially evenly opened gray level when the display is displayed on an axis. FIG. 6 shows the intensity of gray level selection at various viewing angles for a conventional drive scheme.

  FIG. 8 shows the gray level and the transmission as intensity for the viewing directions at −30 ° and + 30 °. For example, when gray level 96 is displayed, pixels displaying this level appear to be substantially black from the + 30 ° viewing area, but half of the maximum brightness when viewed from the −30 ° viewing area. Looks slightly lower. By appropriately selecting the voltage level used to select the gray level according to the first drive scheme and the second drive scheme for the first image and the second image, the first image is The second image can be substantially seen only in the second viewing region. Drive scheme to create a sufficient contrast ratio to display each image in the intended viewing direction and to create a very low or substantially zero contrast ratio in the other viewing areas Is selected.

  A suitable drive scheme is illustrated in FIG. 9, which is the voltage applied to the pixel to select the gray level to be displayed when viewed from −30 ° and + 30 ° (in transmissive mode). Indicates brightness. By using the image 1 voltage range shown at 40 when addressing the pixel on which the first image is to be displayed, the first image is visible in the −30 ° viewing direction, but the first image is displayed. Pixels appear dark in the + 30 ° viewing area. Conversely, by using the image 2 voltage range 41 for the pixel displaying the second image, the first image is visible in the + 30 ° viewing direction, but the pixel is in the −30 ° viewing direction. Looks white. Thereby, the display 10 does not require any parallax optical elements and allows the viewer to view each view without using multi-domain liquid crystal technology with different arrangements for pixels displaying different images. Two viewing areas are created for viewing irrelevant images or sequences of images in the viewing area. Therefore, the display is easy to manufacture and inexpensive.

  In order to be able to provide a full color LCD, the effect of color on the LC mode needs to be taken into account when selecting the driving scheme for the first image and the second image. For a typical color display, the color filter filters the light from each set of pixels. The color may be red, green, blue, cyan, magenta, or yellow. Due to the scattering of the liquid crystal layer 24, the optical characteristics of the liquid crystal mode used in the LCD vary the wavelength of the light. For example, FIG. 10 shows the -30 ° and + 30 ° viewing direction variations for the red, green and blue pixels as gray levels and intensities for each color.

  In order to produce a good color dual view display, the effect of the dispersion of the liquid crystal mode of the grayscale curve can be overcome by making an individual careful mapping of the gray level to each of the color components. FIG. 11 shows that, as a result of such a mapping procedure, the same gray level can be selected and displayed for each of the colors. Thus, the intensity of the image is the same for a given gray level, regardless of whether the color is displaying the image.

  The color mapping can be selected depending on the display application. For example, in some applications it may be desirable to have a higher relative intensity of green light in one or both images for red and / or blue. The mapping can be selected to take into account such requirements.

FIG. 12 shows an alternative dual view display for displaying color images. The display of FIG. 12 differs from the display of FIG. 4 in that the color filter 45 is provided on the inner surface of the substrate 21 and the liquid crystal layer thickness 46 is different for pixels of different colors.
The optical characteristics of the pixel are determined by the retardation of the liquid crystal layer 24 in the pixel. The retardation is the product of birefringence and the thickness 46 of the liquid crystal layer 24. Thus, by varying the thickness of the layer 24 for different color pixels, each of the pixels can be optimized for its characteristics or improved for the color or range of colors to be displayed.

  The display of FIG. 12 has separate step thicknesses for different color pixels. In this particular example, this is done by shaping a polymer step such as 47 on the TFT substrate 26, 27 having the alignment layer 25 formed on top of the step. Such steps may be formed on other substrates below the alignment layer or on both substrates. Step 47 may be formed by photolithography processing of a suitable resist material. Alternatively, step 47 may be formed by screen printing a suitable polymeric material directly on the substrate or each substrate. In a further alternative, the color filter 45 may have a stepped thickness. In another example, to reduce the effect of any misalignment of the LC caused by the sharp edge of the step, the thickness of the liquid crystal layer can be adjusted using a suitably tilted wedge-shaped structure or similar structure without the sharp edge. Variations can be made.

  FIG. 13 shows another technique for compensating for liquid crystal dispersion. In this display, a pixelated retarder 50 is provided. Each “pixel region” of the retarder provides an amount of retardation that substantially compensates for the liquid crystal dispersion effects of the associated pixel. In order to reduce parallax, the pixelated retarder 50 is placed between the substrate 21 and 26, 27. In FIG. 13, the retarder 15 is shown to be disposed on the TFT substrates 26 and 27, but the retarder may alternatively be disposed on the color filter substrate 21.

  Various techniques for creating the pixelated retarder 50 are available. Such techniques are disclosed in van der Zande et al, Sid 03 Digest “Technologies towers Patterned Optical Foils”, pages 194-197. An example of a suitable technique is shown in FIG. 14 and utilizes polymerisable liquid crystals (eg, reactive mesogens, an example of which is RMM 34 available from Merck UK).

  The substrate 53 prepares an array surface such as an array layer 52 to align the optical axes of reactive mesogens. The reactive mesogen is then coated on the alignment layer 52 by any suitable technique (eg, spin coating). Reactive mesogens are a type that is polymerized such that when not polymerized, the birefringence varies with temperature, fixing the orientation of the optical axis exposed to light (eg, ultraviolet light).

  To form a region of the retarder for the first color, layer 51 is exposed to ultraviolet radiation through a photomask while being held at a temperature suitable to control its birefringence. The first region is the region that requires maximum retardation and thereby birefringence.

  Following the first ultraviolet polymerization, layer 51 is heated to a second temperature to provide the desired birefringence for the second region of the completed retarder. This is indicated at 55 in FIG. Accordingly, the birefringence of the unpolymerized reactive mesogen is reduced to the desired value, after which the second region of the next color is exposed to ultraviolet radiation through the second photomask 56. Thus, the second region is polymerized and its properties are fixed.

  The temperature is then increased again as indicated at 57 to reduce the birefringence of the remaining unpolymerized regions, which is polymerized by exposure to ultraviolet radiation through the third mask 58. It becomes. The retarder can then be effectively prepared for use and removed from the substrate 53 and alignment layer 52 for inclusion in a display device of the type shown in FIG. Alternatively, the retarder can be used with the upper substrate and its associated layers to form directly on the TFT substrate shown at 59 in FIG. 14 prior to forming the liquid crystal cell, with the alignment layer on the upper surface. Can be formed.

  Also suitable dyes can be added to the polymerizable liquid crystal to form a color filter for the display. In such cases, the retarders and color filters are formed in a single layer to reduce the number of layers required in the display, thereby simplifying manufacturing and reducing the number of alignment steps required. cut back.

  The viewing angle characteristics of the polarizer 20 and / or the polarizer 28 can be selected or optimized for non-normal incidence of light, so that performance and, in particular, the viewing area of the display Improve image quality.

The voltage used to address gray levels for different views can be selected or optimized by techniques similar to gamma correction. This is well known in the art, for example by Charles Poynton, www. infoamp. It is described in “Frequency Asked Questions about Gamma” available at net / ˜poyton / . This can be done by first remapping the gray level in the original image of each view to the gray level seen from the viewing area of that view. The remapping may be for a single linear range or two or more ranges of intensity levels. Adjustments are made according to the appearance of the image from its viewing area to improve the appearance of the image. This can be done by appropriate gamma correction of the image data. This type of correction cannot take grayscale outside the existing grayscale for the view. Any suitable gamma value can be used according to the effect desired to be obtained. For example, a gamma correction value of 2.2 may be used, or a lower value (eg, 1.7) may be used. Thus, gamma correction can be applied to the color correction curve or the original image prior to color correction.

  Other image intensity adjustment techniques (eg, histogram equalization) may be used.

The range of pixel gray levels for the first viewing area and the second viewing area can be appropriately selected or optimized. For example, select a gray level range to give good image quality in the viewing area where the image is displayed, and the most gray level when pixels are seen from each other viewing range or each other viewing range The state may be given and its level may be substantially white or substantially black and has a minimum contrast ratio over the ray scale range.

  The drive arrangement 29 requires that the pixels can be driven according to different drive schemes (eg, the voltage ranges described above) so that each pixel has an appropriate voltage for the image selected for display. Receive. For displays designed to allow single view mode operation, additional drive schemes (eg, additional voltage ranges) may be used, and the drive 29 provides the appropriate voltage for each pixel. It needs to be possible.

  While the above embodiments were based on twisted nematic liquid crystal modes, any liquid crystal mode that produces an appropriate asymmetric viewing angle may be used. For example, a suitable smectic or ferroelectric liquid crystal mode may be used. Other twisted nematic modes such as hybrid aligned nematic (HAN) mode or twisted vertically aligned nematic (eg, as disclosed in EP 1103840) may be used. The TVAN mode has a vertical structure that does not substantially twist with respect to the substrate below the threshold voltage for switching. Beyond this threshold voltage, this mode gradually switches to more planar twist structures. This is similar to the twisted nematic mode lower than the threshold voltage. An example of the transmission voltage characteristics of a liquid crystal device in TVAN mode for −30 ° and + 30 ° viewing angles is shown in FIG. Can be.

  In the case of multiple view displays, such as the dual view display described above, the images can be spatially multiplexed across the active area of the display device by assigning an appropriate set of pixels to each image. For example, the image may be displayed as an interlaced vertical strip or column of pixels. For video images, the field or frame rate does not change, but the spatial resolution of each image is a display device divided by the number of images displayed, assuming that the pixels are divided substantially evenly into images. Equal to the spatial resolution of Alternatively, for display devices that can operate at a refresh rate higher than the normal video field or frame rate, the images can be multiplexed in time. In this case, the images are displayed one after the other in a sufficiently rapid repetitive cycle so that the central part fuses the intermittently displayed images of each view. The refresh rate of the display device needs to be high enough to avoid display flicker.

  By using temporal multiplexing, each image can be displayed with sufficient spatial resolution of the display device. However, since each image is only displayed for a portion of time, the perceived luminance for each view is reduced for a given level of luminance.

  Time multiplexing or “time series” operation is illustrated in FIG. 16 for the display 10 illustrated in FIG. The transfer characteristics of FIG. 9 are again shown at 70 in the voltage range for images 1 and 2 for the views 1 and 2 shown.

  In the period referred to as “time 1”, image 1 is displayed as shown in the figure at 71. Thus, an observer in the first viewing area looks at image 1 and an observer in the second viewing area sees the display device as black.

  During the second time period indicated as “time 2”, image 2 is displayed as shown at 72 in the figure. In this case, an observer in the first viewing area looks at the display device as white, and an observer in the second viewing area views the image 2.

  This cycle is repeated for still or moving images fast enough for the central part to perform image fusion. Thus, the viewer of the first viewing region fuses the alternately displayed image 1 and the white appearance of the display device and perceives image 1 with a reduced contrast ratio. Conversely, the observer in the second viewing region fuses image 2 and the black appearance of the display device to perceive image 2.

  FIG. 17 illustrates another mode of operation that combines temporal multiplexing with spatial multiplexing. During each frame period, the image is divided into vertical strips interleaved across the display devices described above at 73 and 74 for the time period of time 1 and time 2, as shown. However, during the time 1 period, the strip of image 1 is displayed by the odd-numbered columns of pixels and the strip of image 2 is displayed by the even-numbered columns of pixels. Conversely, in the second period, the strip of image 2 is displayed by the odd-numbered columns of pixels and the strip of image 1 is displayed by the even-numbered columns of pixels. As described above, the viewer in the first viewing area looks at image 1 and the white interlaced strip, and the viewer in the second viewing area looks at image 2 and the black interlaced strip. to see. Therefore, the mode shown in FIG. 17 is equivalent to dividing each image frame into two time-series displayed fields.

  A disadvantage of the embodiment described above is that one of the observers sees a pixel that displays an image that is intended as white for another observer. This has the effect of reducing the contrast ratio of the image. Therefore, it is desirable to use a mode of operation in which each observer sees a pixel that displays an image intended as black for another observer. For example, FIG. 18 shows an illustration of two drive schemes that substantially allow this to be obtained. This type of drive scheme can be obtained using a retarder having a liquid crystal device, an example of which is shown in FIG.

  The display 10 of FIG. 19 operates in the time-series temporal multiplexing mode shown in FIG. 16 and includes a switchable retarder 80 between the front polarizer 20 and the substrate 21. The switchable retarder 80 includes substrates 81 and 82, electrodes 83 and 84, alignment layers 85 and 86, and a liquid crystal layer 87. The electrodes 83 and 84 are planar electrodes and extend across the entire active area of the display so as to switch the entire liquid crystal layer 87 between the first state and the second state. In the absence of an applied electric field, the alignment layers 85 and 86 provide a proper alignment of the liquid crystal layer 87, which is changed when a voltage higher than the switching threshold is applied to the electrodes 83 and 84. The switching is controlled by a drive 29 that supplies the appropriate voltage to the electrodes 83 and 84.

  The switchable retarder 80 is an optional switchable between a first state that provides an odd number of retardation half wavelengths at visible light frequencies and a second state that provides an even number of retardation half wavelengths at visible light frequencies. Any suitable liquid crystal mode may be used. For example, the switchable retarder 80 may include a switchable half wave plate that is switchable between providing a half wavelength of retardation and a substantially zero retardation. Suitable liquid crystal modes for this application include vertically aligned nematic mode and Fredericks mode, both of which are well known in the art. FIG. 20 illustrates the principle of operation during a continuous pair of time periods. During the first time interval, the first angle seen at the viewing angle of −30 ° is displayed with the switchable retarder 80 switched to provide substantially zero retardation. This pixel appears black in the + 30 ° viewing direction.

  During the second time interval, the retarder 80 is switched to provide a half wavelength of retardation, and the image 2 seen in the + 30 ° viewing direction is displayed. The display device appears black in the −30 ° viewing direction.

  FIG. 21 shows the performance of a particular example of the embodiment shown in FIG. Here, the switchable retarder 80 includes a half-wavelength vertically aligned nematic device whose optical axis is 45 ° with respect to the transmission axes of the polarizers 20 and 28 orthogonal to each other. The display device including the components 20 to 28 is a twist vertical alignment nematic type having the optical axis of the liquid crystal layer 24 oriented at 45 ° with respect to the transmission axes of the polarizers 20 and 28. The liquid crystal layer 24 has a thickness of 5 mm, and the liquid crystal material of the layers 24 and 87 has negative dielectric anisotropy.

  No applied voltage is provided between the electrodes 83 and 84 of the retarder 80 during the first time interval of the time series. Accordingly, the layer 87 of liquid crystal directors is substantially homeotropically aligned. Devices 20-28 display images for viewing in the 30 ° direction, and the devices appear substantially black in the −30 ° viewing direction. During the second time period, an applied voltage, for example 23V, is applied between the electrode 83 and the electrode 84 so that the layer 87 of liquid crystal director is substantially planar. Display devices 20-28 display images that are intended to be viewed in the −30 ° viewing direction and appear black from the + 30 ° viewing direction.

  The embodiment shown in FIG. 19 is not limited to the liquid crystal mode described above. For example, it may be embodied by a combination of TN and Frederix; TN and VAN; TVAN and Fredericks mode.

  FIG. 22 illustrates another technique using a spatially multiplexed display so that pixels displaying one image intended for another viewing area appear black or substantially black. . The display is of the type shown in FIG. 4 except that the polarizer 28 is a patterned polarizer. A set of pixels 1 for displaying the first image is placed between the crossed or orthogonal polarizer regions, and a set 2 of pixels for displaying the second image is placed between the parallel polarizer regions. Is done. The device uses a 90 ° TVAN mode with a liquid crystal layer 24 having a thickness of 5 mm and negative dielectric anisotropy. The graph in FIG. 22 shows voltage and transmittance for two sets of pixels. The set of pixels 1 for displaying the first image in the first viewing area appears black when viewed from the second viewing area. The set of pixels 2 for displaying the second image in the second viewing area appears relatively black in the first viewing area, but this black appearance is suitable for the gray level voltage range. It can be improved by optimizing and selecting.

  In order to reduce the parallax effect between the liquid crystal pixels and the patterned polarizer 28, the space between them should be sufficiently small. For example, the patterned polarizer 28 may be disposed inside the substrate 27, and the substrate 27 may be relatively small.

  The display shown in FIG. 22 may be configured to operate in a single view mode that is intended to be viewed at normal incidence. In particular, the normally white and normally black TVAN modes of crossed and parallel polarizers have grayscale curves that are nearly opposite to the normal incidence viewing shown in FIG. To operate a display for normal incidence viewing, the gray level voltage for the first set of pixels between the crossed polarizer regions is increased, the gray level voltage for the second set of pixels is decreased, The same image is displayed by all pixels of the display. This mode of operation can be used for other liquid crystal modes.

  Another technique that can be used with spatially multiplexed type displays is between the polarizers 20, 28 of a patterned retarder (eg, patterned half-wave plate) in the case of a liquid crystal mode (eg, TN, TVAN, etc.). included. FIG. 24 shows an example of such a display using a 90 ° TVAN mode with the optical axis oriented at 45 ° with respect to the crossed polarizer. The liquid crystal layer has a thickness of 5 mm and negative dielectric anisotropy. A reactive mesogen retarder is disposed between the device substrates so as to provide a half-wave of retardation for the second set of pixels and an qualitatively zero retardation for the first set of pixels. Patterned. This is shown in the figure as a half-wave layer 90.

  Along with crossed polarizers, the first set of pixels is operated in a normally black mode, and the presence of a half-wave plate having a second set of pixels is made to operate in a normally white mode. The transmission graph of FIG. 24 shows this effect in each viewing region, such that the pixels displaying the image seen in the different viewing regions appear black or appear substantially black.

  In addition to improving the contrast ratio, a patterned retarder can be used to modify or optimize viewing angles and gray scale characteristics. For example, for this purpose, the patterned retarder may have non-zero retardation regions arranged for the first set of pixels. Further, more than one retarder layer may be provided to improve the color performance of the display. The second retarder layer can be uniform or patterned, and each of the patterned retarders or patterned retarders may be disposed between display device substrates to reduce the effects of parallax.

  Patterned retarders suitable for such use can be made by a variety of methods. For example, polymerizable liquid crystals such as reactive mesogens can be selectively deposited by screen printing and then polymerized, for example, by exposure to ultraviolet light. Examples of suitable techniques are disclosed in European Patent Application No. 0887692 and British Patent Application No. 2384318.

  This display can also be used in a single image display mode seen at or near normal incidence. The normally white and normally black TVAN modes have nearly opposite grayscale curves for orthogonal incidence viewing shown in FIG. For such viewing, increase the voltage to give an increased grayscale output output for normally black pixels, and increase the voltage to give a reduced grayscale output for normally white pixels. The drive scheme can be changed to decrease. The same image is then displayed by all of the pixels in the active area of the display device.

  In an alternative technique for providing a display that is switchable to single view mode operation, the patterned retarder may be of a switchable type using, for example, a VAN mode or a Fredericks mode. If a single view operation is required, the retarder is switched to convert all pixels to either normally black or normally white operation.

  In a further technique for providing a display switchable to single view mode operation, the same image can be displayed for both views when a single view is required.

  Another approach to prevent a pixel from displaying an image in one viewing area and being seen as a white pixel in another viewing area is to use a parallax barrier 95 as shown in FIG. is there. Such a barrier 95 limits the viewing angle of the pixels so that only pixels intended to display an image to be seen in the viewing area are seen in that area and other pixels are not visible. Configured.

  The parallax barrier may be formed from an emulsion, for example. However, conventional emulsions used for parallax barriers reduce the brightness of the display. Alternatively, a partial transmission barrier may be used to provide improved brightness and contrast. The parallax barrier may be formed from a patterned retarder, for example as disclosed in GB 2390172. Also, when using a switchable retarder, the barrier can be switched off to provide single view mode operation for viewing at or near normal incidence.

  Although the number of pixels used for images of different views may not be equal, having the same number has the advantage if the same spatial resolution is required for each image. Also, the distribution of pixels assigned to display different views need not be uniform and need not alternate across the display device. For example, it may be desirable to provide a high resolution area for one of the viewers to display text with a small front size. Thus, an increased number of pixels in that region is assigned to that view. In some embodiments, the multiple view effect basically depends on driving the display device, which may otherwise be uniform. Thus, each of the pixels of the display device can be assigned to any of the views, and this can be changed by selecting an appropriate applied voltage range at any time.

  When viewed by a person with a dual view display, as shown in FIG. 27, both the size of the panel and the distance from the panel to the person affect the angle at which the extreme edges of the panel move the person's eyes. In the case of the panel 100 having a width of 8 cm, the angle range in which the gray scale correction is performed is 23 ° to 35 °. With increasing angle range, software image correction techniques can be used to prevent changes from being observed at the extremes of the image.

  FIG. 28 is for directing two views of images 1 and 2 that may be unrelated in viewing regions 1 and 2 relative to viewers 1 and 2 as shown in FIGS. 2 shows a dual view thin film transistor (TFT) active matrix LCD. The display includes a front linear polarizer 20 that is attached to or formed on the outer surface of the substrate 21. The substrate 21 can be made of glass or any suitable transparent non-birefringent material of sufficient stability. The substrate 21 has a transparent electrode 22 made of, for example, indium tin oxide (ITO) on its inner surface. The electrode 22 functions as a counter substrate for the active matrix and uniformly covers the entire active area of the display 10. For example, an array surface such as a rubbing polyimide array layer 23 is formed on the electrode 22.

  The second substrate 27 has a rear linear polarizer 28, a TFT, and an electrode layer 26. The electrode layer 26 is patterned to define pixels (picture elements). Such TFT and electrode arrangements are known and will not be further described. For example, an alignment surface 25 such as an alignment layer 23 of rubbing polyimide is formed on the layer 26.

  Substrates 21 and 27 are formed with layers 22, 23, 25, 26 and define a liquid crystal cell in which alignment layers 23, 25 facing each other are gathered and a liquid crystal layer 24 is interposed therebetween. The liquid crystal layer 24 is a nematic liquid crystal. The polarizers 20 and 28 may be formed or provided before or after the liquid crystal cell is formed. Layer 26 includes or is connected to a driver, indicated at 29, to provide a signal suitable for addressing individual pixels at a voltage defining gray scale. Device 29 may form all or part of the external components to provide the appropriate drive scheme for the first and second images to be displayed. Alternatively, the device 29 can be mounted on the panel using, for example, continuous particle silicon.

  The LCD is pixelated to provide a first set of pixels 101 and a second set of pixels 102 for displaying images 1 and 2 to be viewed in different directions. Pixels 101 and 102 are spatially multiplexed or distributed with each other so that each image is viewed from the viewing direction over the entire display surface of the display. For example, the pixels 101 and 102 can be comprised of a checkerboard pattern or alternating vertical strips of one or more columns of pixels.

  The pixel 101 has a first configuration, and the pixel 102 has a second configuration that is different from the first configuration. Different configurations may be characterized by differences in any one or more of the following features. Pretilt on one or both surfaces of liquid crystal layer 24; bulk liquid crystal director alignment in layer 24; thickness of layer 24; twist in the absence of applied electric field; doping of liquid crystal layer 24; either or both of polarizers 20 and 28 Orientation axis and / or zenith angle anchor of liquid crystal substrate interface in alignment layers 23 and 25; retarder and / or compensation film (not shown in FIG. 28); material of liquid crystal layer 24; Driving method such as voltage range provided by.

  In embodiments where the pretilt is different for the pixels 101 and 102, either or both of the alignment layers 23 and 25 can be appropriately patterned to provide a different pretilt for the pixels 101 and 102. The pretilt may be different for magnitude, direction, or both.

  When the bulk liquid crystal director orientation is different between the pixel 101 and the pixel 102, the alignment layers 23 and 25 can be patterned to provide different pretilts and / or alignment directions at the liquid crystal layer surface. The combination of the pretilt characteristic and the alignment direction determines the liquid crystal director alignment in the bulk of the liquid crystal layer 24.

  The thickness of the liquid crystal layer 24 in the pixels 101 and 102 may be different from each other. This will be described in more detail below.

  If the twist is different between pixel 101 and pixel 102, the angle and / or effect of the twist between pixels, i.e. clockwise or counterclockwise in the absence of an electric field between electrode 22 and electrode 26 Can be different. Further, for example, the pixel 101 may be zero twist, or may be non-zero in the pixel 102 without an electric field between the electrodes 22 and 26.

  The liquid crystal layer 24 may include a chiral dopant. The thickness and alignment differences between pixels 101 and 102 along with the effect of such chiral dopants affect the bulk director orientation of layer 24, for example, suppressing that orientation and with a given hardness and pitch. A twist structure is formed.

  The LC layer 24 may also include dopants such as dyes or polymeric materials to improve the viewing characteristics of the LCD.

  Polarizer 20 and / or polarizer 28 may be patterned such that the transmission axis of the polarization region of pixel 101 relative to the optical axis of pixel layer 24 may be different from that for pixel 102.

  By providing a difference in the anchor strength of the liquid crystal director at the interface between either or both of the alignment layers 23 and 25 and the adjacent layer 24 of liquid crystal material, the switching characteristics of the liquid crystal material in the presence of an applied voltage is , The pixels 101 and 102 may be different.

  Although not shown in FIG. 28, a retarder and / or compensation film may be provided for either pixel 101 or pixel 102, or for both. For example, patterned retarders and / or compensation films may be used with different retardations or different compensation effects between the pixels 101 and 102.

  As described in detail below, different liquid crystal materials may be used for the pixels 101 and 102. By using different materials, the birefringence, elastic constant, dielectric constant may be appropriately selected and may be different for the pixels 101 and 102.

  The difference in liquid crystal director structure and anchor may be combined with the difference in dielectric constant and elastic constant, thereby using different voltage ranges for the pixels 101 and 102. Accordingly, the driving device 29 provides an appropriate driving scheme (eg, an appropriate voltage range) for optimizing the quality of the first image and the second image in each viewing area, and other viewing areas. Minimize in areas and make pixels relatively dark or black in other areas.

  FIG. 29 illustrates the polarizers 20 and 28 and layers 23 to 25 in an exploded view for the particular embodiment of the display 10 shown in FIG. 28 using twisted vertically aligned nematic (TVAN) liquid crystal mode. Show. FIG. 29 also shows the vertical and horizontal directions for the vertical orientation of the display 10 as in FIG. The vertical upper reference direction is called 0 °, and the horizontal perpendicular direction is called 90 °. The various directions shown for the components shown in FIG. 29 are referred to the upward vertical 0 ° direction.

  The front polarizer 20 has a transmission axis 30 oriented at 180 ° (equivalent to 0 ° as shown) with respect to the upper vertical direction. The array 23 is patterned with an array direction 33a for pixels 101 oriented at + 90 ° with respect to the upper vertical orientation and an orientation direction 33b for pixels 102 oriented at + 70 ° with respect to the upper vertical direction. With different arrangement directions. The alignment layer 25 is also patterned to have an alignment direction 35a oriented at + 180 ° with respect to the upper vertical direction relative to the pixel 101 and an alignment direction 35b oriented at 0 ° relative to the upper vertical direction relative to the pixel 102. ing. The polarizer 28 has a transmission axis 38 oriented at + 90 ° with respect to the upper vertical direction. Accordingly, polarizers 20 and 28 are uniform and are not patterned.

  In the particular embodiment of the display shown in FIGS. 28 and 29, the liquid crystal layer 24 has a thickness of 3.7 mm in the region 34 a of the pixel 101 and a thickness of 4.0 mm in the region 34 b of the pixel 102. Have. The liquid crystal is of the type known as MJ97174 available from Merck UK.

  Patterned alignment layers 23 and 25 are disclosed in, for example, Harold et al., Sharp technical journal “3D display systems hardware research Laboratories of August 74, Issue 74; ing.

  A material such as polyimide PI2555 available from Dupont UK is coated onto the substrate, for example by spin coating. The layer is suitably cured, for example by heat treatment, and then rubbed uniformly to define a specific alignment direction and pretilt when in full contact with the liquid crystal material. A photoresist such as S1865 available from Shipley UK is coated on the rubbed polyimide layer. For example, the photoresist is exposed to ultraviolet radiation through a suitable mask so that the region corresponding to the pixel 101 is exposed and the region corresponding to the pixel 102 is not exposed. The resist is developed so that the region of the alignment layer is protected by the photoresist for one of the set of pixels and the other pixel regions are exposed. A further rubbing operation is then performed with a different direction and different rubbing intensity than the first rubbing operation, producing a different alignment direction and pretilt. The photoresist is then removed to provide two sets for pixels 101 and 102 having different alignment directions and pretilts.

  Alternatively, a photo alignment technique may be used instead of the rubbing technique. For example, after the first uniform exposure, the second patterned exposure may be continued in order to change the alignment direction and the pretilt of the first exposure. Photoalignment may be done by utilizing bond breakage, bond creation, or photoreorienting materials (eg, azo dyes).

  Alternatively, a combination of rubbing and photo alignment may be used to define the alignment direction and pretilt of the patterned alignment layer.

  Further possibly, a microstructure array surface of the type disclosed in GB 2384318 may be provided.

  Other techniques such as photolithography and polymeric embossing may be used. For example, a microstructured array surface may be provided and steps may be formed at the polymer layer thickness between different sets of pixels 101 and 102. Such techniques may be used to provide pixels with different liquid crystal layer thicknesses without requiring any other processing steps other than the formation of alignment layers.

  In the display of FIGS. 28 and 29, pixel 101 and pixel 102 appear to be maximally dark or “black” in the respective viewing directions in the absence of an electric field applied between electrode 22 and electrode 26. , Normally black type. In this case, the liquid crystal layer 24 is arranged substantially homotropically. When voltage is applied across the liquid crystal layer of either pixel 101 or pixel 102, light is transmitted in the viewing direction of the pixel. The transfer function of pixel 101 and pixel 102 is shown in FIGS. 30 and 31, respectively, as the brightness of transmission for applied voltages for the −30 ° and 60 ° viewing directions perpendicular to the display surface in the horizontal plane. The drive 29 supplies a voltage in the range to produce a gray scale in the + 60 ° direction, and these pixels 101 appear to be substantially black in the −30 ° direction. Conversely, driver 29 provides a voltage to select a gray level in the −30 ° viewing direction for pixels 102, and these pixels appear substantially black in the + 60 ° viewing direction.

  FIG. 32 shows the luminance ratio with respect to the applied voltage to the pixel 101, and particularly shows the luminance ratio for an image viewed from + 60 ° divided by the luminance in the black state at −30 °. This ratio is very high, for example over 100 up to 25% transmission.

  FIG. 33 shows another embodiment of a display having pixels 101 operating in a Fredericks or non-twisted planar alignment nematic mode and pixels 102 operating in a twisted nematic mode. The front polarizer 20 has a transmission axis oriented at 180 ° with respect to the upper vertical direction. The array layer 23 includes a region corresponding to the pixel 101 having the array direction 33a oriented at + 45 ° with respect to the upper vertical direction, and a pixel 102 having the array direction 33b oriented at + 90 ° with respect to the upper vertical direction. It is put into the corresponding area. Similarly, the arrangement layer 25 has a region corresponding to the pixel 101 having the arrangement direction 35a oriented at + 45 ° with respect to the upper vertical direction, and an arrangement direction 35b oriented at + 180 ° with respect to the upper vertical direction. The area corresponding to the pixel 102 is put into a pattern. The polarizer 28 is uniform and has a transmission axis 38a oriented at + 90 ° with respect to the upper vertical direction. The liquid crystal layer 24 has a uniform thickness of 2 mm, for example, and may include a material known as E7 available from Merck UK.

  The displays shown in FIGS. 28 and 33 operate in normally white mode. With no voltage applied between the electrode 22 and the electrode 26, the liquid crystal layer 24 is arranged in a planar non-twisted arrangement for the pixel 101 and a planar 90 ° twist for the pixel 102. Accordingly, the liquid crystal layer 24 rotates the polarization direction of the light passing therethrough by 90 °. When a voltage is applied between the electrode 22 and the electrode 26 to either the pixel 101 or the pixel 102, the pixel transmits light according to the applied voltage and provides a gray scale. Pixel 101 and pixel 102 show FIGS. 34 and 35, respectively, as the luminance in transmission with respect to the applied voltage at viewing angles + 60 ° and −30 °. The drive device 29 displays the grayscale image as seen in the −30 ° direction, but supplies the voltage to the pixel 101 in a voltage range such that these pixels appear substantially black in the + 60 ° direction. Conversely, the drive 29 supplies a voltage to the pixels 102 for displaying gray scale in the + 60 ° direction, and these pixels appear substantially black in the −30 ° viewing direction. The luminance ratio for Fredericks pixel 101 and twisted nematic (TN) pixel 102 (as defined above) is shown in FIG. 36, which is very high, eg, 20% for both types of pixels. Is at least 200.

FIG. 37 shows the display 10 in which the liquid crystal layer has different thicknesses for different pixels 101 and 102. Different thicknesses may be obtained by any suitable technique, for example as disclosed herein. FIG. 37 also shows different viewing angular directions a ₁ and a ₂ in the horizontal plane relative to the display perpendicular to the image displayed by the set of pixels 101 and 102. In general, the viewing angles a ₁ and a ₂ are required to be substantially larger than conventionally used for autostereoscopic displays. For example, for a typical autostereoscopic display, the angle between viewing directions may be on the order of 10 °. For images to display irrelevant or non-autostereoscopic images for two different observers, the angular separation between viewing directions is generally much larger and can be asymmetric (a ₁ to a ₂ Not equal). For example, when the display 10 is used in a car dashboard where the viewers can be at different heights and thus can sit at different distances from the display, the viewing angles a ₁ and a ₂ are of different sizes. Also good. Also, the operation of the display can be optimized for different viewing angles so that it can adapt to different observer positions.

  For example, as described below, known types of patterned arrays or multi-domain configurations can provide optimization or sufficient image quality with a relatively wide or large viewing angle required. The description disclosed herein enables this and allows the pixel to appear relatively dark when viewed from the unintended viewing direction of the pixel.

  The combination of liquid crystal material and alignment surface has a substantial effect on the bulk liquid crystal director configuration. By providing different materials for different pixels and using them to form an array surface, differences in anchor strength (azimuth and / or zenith angle) may be obtained, resulting in differences in liquid crystal director structures The behavior may switch from one type of pixel 101 to another type of pixel 102. This is used to provide two or more sets of pixels in a single liquid crystal device so that each set displays a grayscale image in its viewing direction and dark in the other viewing direction, or Looks black.

  In order to provide pixels of different liquid crystal layer thickness, the step is performed by etching a glass substrate on one or both of the substrates, for example by photolithography, by techniques such as embossing of a suitable polymeric material, Alternatively, it may be formed by any other suitable technique. The array surface may then be formed on a stepped surface. Then, using two stepped substrates or one stepped substrate and a uniform counter substrate, a liquid crystal cell having a different thickness of the liquid crystal layer for the pixel 101 and the pixel 102 can be formed.

  In displays that use different liquid crystal materials for different pixels 101 and 102, it is necessary to include each of the liquid crystal materials and provide a different arrangement from that liquid crystal material or each liquid crystal material. This can be done, for example, by forming polymer walls on either or both substrates by photolithography of a high binary resist material such as SU8 available from MicroChem. FIG. 38 shows that the polymer wall 110 extends substantially vertically in a separate path leaving a filling hole 111 for the first liquid crystal material (LC1) and a filling hole 112 for the second liquid crystal material (LC2). This type of configuration is shown.

  For example, one liquid crystal material LC1 can be chirally doped to define a specific twist effect, and the other liquid crystal material LC2 cannot be doped. Thereby, a certain twist effect can be preferably selected when the arrangement condition is otherwise a twist degeneracy. Alternatively, different dopings for different materials may be used. One material may have a positive dielectric anisotropy and the other liquid crystal material may have a negative dielectric anisotropy. Liquid crystal materials having different birefringence and / or different elastic moduli may be used.

  FIG. 39 shows image 1 and image due to overlapping viewing angle characteristics of pixel 101 and pixel 102 in addition to the viewing region for viewer 1 and viewer 2 where a single view is substantially seen respectively. 2 shows a dual view display 10 with a “crosstalk area” 115 in which both are seen. In certain applications, the crosstalk region 115 is undesirable and the display 10 can be designed or optimized to minimize crosstalk. In some applications, the crosstalk region may be replaced with a black central region. However, in other applications, crosstalk 115 may be used. For example, for a company presentation that a first person wants to display information on a laptop or PC monitor to a second person, or for customer use, the first person (observer 1) As shown in FIG. 40, the display 10 can be viewed from the crosstalk area. Thus, the viewer 1 can see the image 1 and the image 2 that substantially overlap each other, and in this application, the display sacrifices the overlapping image of the region 115, for example, the quality of the image of the viewing region 1. And can be controlled or optimized to improve. The viewer 2 in the viewing area 2 substantially sees only the image intended for the viewer 2. For example, if the viewer 1 is demonstrating, the image 1 may include further details to the image, such as a prompt for a presentation or menu option, so that the image data shown to the viewer 2 can be selected. . The display 10 also operates as a dual “separate” view display or a single view display with high resolution (eg, optimized for normal incident viewing) when the demonstration hunts. Also good.

  In yet another application, it is desirable to utilize a viewing area 1 where image 1 and image 2 are only visible to viewer 1 and viewer 2, respectively, and a crosstalk region 115 where both images can be viewed simultaneously. obtain. This example is a multiplayer game in which a player in the crosstalk area 115 can see all of the image data and a player in a zone on either side can see only a part of the image data.

  The display described below is of a type in which two unrelated images (eg, by being non-stereoscopic) are displayed and, for example, two viewers view different images simultaneously from different viewing areas. However, by optimizing viewing angle characteristics, the crosstalk region can be sufficiently reduced or substantially eliminated so that a display providing more than two views can be displayed. For example, as shown in FIG. 41, four different unrelated (or related) images are directed to four viewing regions by using four different types of pixel configurations of a liquid crystal device, thereby A human observer can see different images displayed simultaneously on the same device.

  Alternatively, as shown in FIG. 42, four device configurations 120 are displayed by two liquid crystal devices 121 and 122 having stacked devices, whereby one device 122 is routed through the other device. It is possible at times. For example, the device can operate in time series, so that in one time frame, one of the devices supplies images to two viewing areas, black in the other area, and liquid crystal in the second time frame. The device role is reversed. Such a configuration provides images with twice the resolution (assuming all images are displayed with the same spatial resolution) compared to the configuration shown in FIG.

  A suitable hologram can be used to eliminate or reduce the crosstalk region.

  In order to prevent or reduce the changes described above with reference to FIG. 27, the position may be optimized across the panel, alternatively or in addition to software correction techniques, alignment layer patterning. This can be used, for example, to change the twist angle across the panel for each set of pixels 101 and 102 in opposite directions depending on the selected viewing direction. Angular variation across the panel for a set of pixels can be made by using the effect of angular variation in the light alignment direction with exposure energy. This can be done, for example, by a scanning ultraviolet source incident on the light alignment layer and by varying the ultraviolet flux when the beam is scanned across that surface to produce a change in angle across the surface. During this time, other regions may be masked. This ultraviolet source may be polarized.

  Alternatively, a variable amplitude mask may be used with a uniform ultraviolet exposure source. As a further alternative, an array may be used to rotate the angle across the panel, eg, a phase mask formed by different oriented wave plates. This can be used with bond breaking or bond making light sequences.

  Alternatively, different liquid crystal materials may be used across the panel to optimize image quality.

  The gray level range used for pixel 101 and the gray level range used for pixel 102 may be optimized. For example, optimization may be the best image quality in the viewing direction, with each pixel displaying an image and in the best gray level state (eg, substantially black) relative to other viewing directions. It may be for providing. If different voltage ranges are required to operate such a display in a dual or multi-view display and / or single view normal incidence mode, the drive 29 is required to influence the appropriate voltage range It is said to be a spear.

  A dual view display may be used as a single view or a 2D display. When such a display is used for normal incidence viewing, the vertical and horizontal angular range at which a single view is viewed with good quality can be reduced compared to a single view type of conventional displays. In order to improve the normal incidence viewing of multiple view displays, different sets of pixels appear to differ due to different configurations to optimize the range over which a single image can be viewed with acceptable quality. May need to be driven to.

  Flexibility to adjust the required viewing angle characteristics for a limited range is an angle that is optimized by changing the grayscale range used until the image is correct or optimal for the user This can be done by adjusting For example, if such a display is used in a car dashboard, this may be done at the same time as the driver or passenger adjusts its seat and rear view mirror. Alternatively, the position of the observer (s) in the vehicle may be located using a suitable tracking device so that compensation for different viewing angles is automatically performed.

  In applications where a single view is required to be seen in the multiple view viewing area, but not necessarily at normal incidence of the display, all of the set of pixels may display the same image. This does not require any changes to the voltage range used for the set of pixels, for example. However, each observer sees the same image with a lower spatial resolution compared to a form in which a single image is displayed using all of the pixels.

  In order to be able to provide a full color LCD, the techniques described above and shown in FIGS. 10-14 can be used.

  Although embodiments with two sets of pixels 101 and 102 are based on TVAN, TN and Frederick liquid crystal modes, any liquid crystal mode that provides an appropriate asymmetric viewing angle may be used. For example, a suitable smectic or ferroelectric liquid crystal mode may be used. Further, other twisted nematic modes (for example, a hybrid alignment nematic (HAN) mode or a pi-cell mode) may be used.

  Viewing angle compensation films are known in the art. Van de Witte et al., “Viewing angle compensators for liquid crystal displays based on layers in a positive 101”, Japan Journal 108, published in Japan. Such films are used to optimize liquid crystal mode characteristics, such as viewing angle characteristics and / or black / white and gray level conditions. In known single view displays, such a film is used to generate viewing angle characteristics that are as uniform as possible in the vertical and horizontal directions to optimize gray levels.

  For the multiple view display disclosed herein, the different requirements for the grayscale viewing angle characteristics of the liquid crystal mode require different optimization than known configurations, and therefore when using such a film. Different designs of viewing angle compensation films are required. Such viewing angle compensation film requirements optimize each image when viewed in its viewing direction and make the appearance of the pixels displaying the image to be viewed in the other direction as black as possible.

  More than one retarder layer can be used to improve the chromatic properties of the image. For example, two retarders may be used, and each may be patterned or uniform. Such retarders may be formed from liquid crystal layers or polymerizable liquid crystals (eg, reactive mesogens) and may be used inside the liquid crystal cell to reduce or eliminate parallax effects. Alternatively, a thin substrate may be used between the patterned lidar and the liquid crystal layer.

  Alternatively, such a retarder may be external to the liquid crystal cell. As a further alternative, the uniform retarder may be laminated out of the cell or fixed outside the cell.

  Patterned retarders may be made by any suitable technique, and known examples of several techniques are disclosed in UK Patent Application Publication No. 2384318 and European Patent Application Publication No. 0887692.

  FIG. 43 shows images that may be irrelevant in two views in viewing region 1 and viewing region 2 for viewer 1 and viewer 2, respectively, as shown in FIGS. Includes two thin film transistor (TFT) active matrix twisted vertically aligned nematic (TVAN) LDCs for orientation. The first LCD includes a first linear polarizer 20 formed thereon or on the outer surface of the substrate. The substrate 21 may be made of glass or any suitable transparent non-birefringent material that is sufficiently stable. The substrate 21 has a transparent electrode made of, for example, indium tin oxide (ITO) on the inner surface thereof. The electrode 22 functions as an active matrix counter electrode and uniformly covers the entire active area of the display 10. For example, an array surface such as an alignment layer 23 of rubbing polyimide is formed on the electrode 22 and is uniformly rubbed to have the same uniform alignment direction over the active area of the display 10.

  The second substrate 27 has an intermediate linear polarizer 28, a TFT, and an electrode layer 26. The electrode layer 26 is patterned to define pixels (picture elements). Such TFT and electrode configurations are well known and will not be further described. For example, an alignment surface such as alignment layer 25 of rubbing polyimide is formed on layer 26. The alignment layer 25 provides a uniform alignment direction across the active area of the display 10.

  The substrate 21 and the substrate 27 are formed so as to have the layers 22, 23, 25 and 26, and are gathered together with the alignment layer 23 and the alignment layer 25 facing each other, and a liquid crystal cell having the liquid crystal layer 24 therebetween. Stipulate. The liquid crystal layer 24 is, for example, a nematic liquid crystal containing MJ97174 available from Merck UK. The polarizer 20 and the polarizer 28 may be formed before or after the liquid crystal cell is formed, or may be provided. Layers 22 and 26 include or are connected to a driver, indicated at 29, to provide appropriate signals for addressing individual pixels with voltages defining gray scale. Yes. Device 29 may be formed on all or some of the external components. Alternatively, device 29 may be integrated on the LCD, for example using continuous particle silicon.

  The second LCD has the same type of substrate 21 ′, electrode 22 ′, alignment layer 23 ′, liquid crystal layer 24 ′, alignment layer 25 ′, TFT and electrode layer 26 ′, and substrate 27 ′ as the corresponding components 21 to 28. A polarizer 28 '. Layer 22 ′ and layer 26 ′ are connected to drive device 29. A display is provided with the backlight 30, which can also be controlled by the drive 29.

  The driving device 29 provides a first driving method and a second driving method for the first image and the second image to be displayed on the first LCD and the second LCD. These driving methods will be described in detail below.

  Although the first LCD and the second LCD are shown as substantially independent devices integrated together, the LCD can be made by a single integrated device. For example, substrate 27 and substrate 21 'can be replaced by a single common intermediate substrate. In some embodiments, the intermediate polarizer 28 may be omitted.

  FIG. 44 shows, in an exploded view, polarizers 20, 28 and 28 'and layers 23-25 and layers 23'-25'. 44 also shows the vertical and horizontal directions relative to the normal orientation of the display 10 shown in FIG. The vertical information reference direction is regarded as 0 °, and the horizontal perpendicular direction is regarded as 90 °. The various directions shown for the components shown in FIG. 44 are considered the upper vertical 0 ° direction.

  The front polarizer 20 has a transmission axis 31 oriented at an angle of + 90 ° with respect to the upper vertical. The alignment layer 23 has a uniform alignment layer 32 oriented at + 90 ° with respect to the upper vertical direction. The alignment layer 25 has a uniform alignment layer 33 oriented at 0 ° with respect to the upper vertical direction. The polarizer 28 has a transmission axis 34 oriented at + 180 ° with respect to the upper vertical direction. The alignment layer 23 ′ has a uniform alignment direction 35 oriented at + 270 ° with respect to the upper vertical direction. The alignment layer 25 ′ has a uniform alignment layer 36 oriented at + 180 ° with respect to the upper vertical direction. The polarizer 28 ′ has a transmission axis 37 that is oriented at + 90 ° with respect to the upper vertical direction.

  The apparatus shown in FIGS. 43 and 44 includes two TVAN (twisted vertical alignment nematic) LCDs operating in normally black mode operation. In the absence of an applied voltage across either of the liquid crystal layers 24 and 24 ', the liquid crystals are arranged substantially homotropically so that no light is transmitted. If both liquid crystal layers 24 and 24 'have a sufficiently large applied voltage across them, light is transmitted. However, as the voltage across the liquid crystal layer 24 'decreases, the amount of light entering the other liquid crystal layer 24 progressively attenuates so that the range of gray levels that can be displayed progressively decreases.

  This effect is shown in FIGS. 45 and 46. FIG. FIG. 45 shows the light transmission through the liquid crystal layer 24 with respect to the applied voltage for the liquid crystal layer 24 'switched in voltage selection with respect to the viewing angle direction of -30 [deg.] Perpendicular to the display. Conversely, FIG. 46 shows the transmission through the liquid crystal layer 24 'with the liquid crystal layer 24 switched in the voltage selection in the + 30 ° viewing direction.

  FIG. 47 shows the effect of removing or omitting the intermediate polarizer 28. If a voltage is applied across one of the layers (eg, layer 24 having another layer 24 '), the display behaves as a white-white TVAN LCD. If a voltage greater than the threshold for switching is applied to layer 24 ', the display will resemble a normally black TVAN LCD. FIG. 47 illustrates this in terms of voltage and transmittance through the liquid crystal layer 24 with the layer 24 ′ switched in selecting a voltage for a viewing angle of −30 °.

  Techniques for overcoming or reducing certain liquid crystal layer switching problems that affect light available through other liquid crystal layers are described below.

  FIGS. 6-9 show the characteristics of a single LCD similar to that shown in FIGS. 43 and 44, but operating in twisted nematic (TN) mode.

  FIG. 48 shows the drive scheme used for the two LCDs forming the display shown in FIG. The driving scheme for the upper LCD including the LC layer 24 is shown at 42 and the lower LCD including the LC layer 24 ′ is shown at 43. The LCDs are of the same type and are substantially the same as each other, but the lower LCD is substantially rotated 180 ° relative to the upper LCD. Therefore, the alignment direction of the alignment layers 23 ′ and 25 ′ is rotated by 180 ° with respect to (or opposite to) the alignment direction of the alignment layers 23 and 25, respectively.

  The voltage range 40 may be used as a driving method for each of the LCDs. Thus, as shown at 42, the top LCD is used to display the image by appropriately mapping the voltage to the appropriate gray level in range 40, so that the image is viewed in the −30 ° viewing direction. However, the pixels of the upper LCD appear substantially black with a contrast ratio substantially equal to 1 when viewed in the + 30 ° direction.

  The same drive scheme is shown at 43, but the viewing direction corresponds to the viewing direction of the lower LCD. Thus, in the + 30 ° viewing direction, the lower LCD appears substantially black with a contrast ratio substantially equal to 1 in the −30 ° viewing direction. Thus, the display 10 allows each viewer to view each viewing region without the need for any parallax optic and without using multi-domain liquid crystal technology with different arrangements for pixels displaying different images. Create two viewing areas for viewing an irrelevant image or sequence of images. Therefore, such a display is easy to manufacture and inexpensive. Techniques for overcoming or reducing certain liquid crystal layer switching problems that affect light available through other liquid crystal layers are described below.

  As an alternative to the drive scheme described above, a voltage range 41 can be used for each of the LCDs. In this case, the upper LCD displays an image that appears in the + 30 ° viewing direction but appears bright or “white” in the −30 ° viewing direction. Conversely, the lower LCD displays an image that appears in the −30 ° viewing direction but appears white in the + 30 ° viewing direction.

  Since two “stacked” or “continuous” LCDs are used in the optical path of display 10, it is necessary to consider using color filters to provide a color display. If only one LCD is provided with a color filter, light from the other LCD needs to pass through the color filter in an accurate manner to avoid inaccurately coloring the displayed image. For example, FIG. 49 illustrates liquid crystal layers 24 and 24 ′ with finite liquid crystal layer separation 44. The LCD is pixelated with the same pixel pitch shown in 45, for example. The display is such that the first viewing angle and the second viewing angle are substantially the same and are defined by a minimum angle a and a corresponding maximum angle b, respectively. In order to ensure that light passes along the exact light paths 46 and 47 through the display, the absorption region shown as part of the black masks 48 and 49 blocks at least some inaccurate light paths. Provided to be. FIG. 50 shows an embodiment where both LCDs have color filters. The filters for each color are indicated by the same cross-hatching as the liquid crystal layers 24 and 24 '. The light passing through the pixel 50 is encoded with the corresponding color and enters the color filter of the upper LCD. Depending on the color of the incoming color filter, the light is transmitted or absorbed. FIG. 50 shows the relative position of the color filter relative to the two LCDs having pixel 51 and pixel 52 having the same color filter as the filter of pixel 50.

  Similar to FIG. 49, FIG. 50 shows the main angular range through the pixel 51 for the light from the pixel 50. This is largely defined by the relationship between the color pixel pitch of layers 24 and 24 'and the separation 44 between the liquid crystal layers of the LCD. Separation 44 is important because light needs to be able to reach layer 24 'in order to encode the data to form both images to be displayed. This therefore provides a constraint on the separation 44 between layers for a given color pixel pitch. In general, for practical purposes, the separation 44 is required to be relatively small and can be smaller than would normally be possible for a conventional LCD component as shown in FIG.

  In order to reduce the thickness, the two substrates 27 and 21 'can be replaced by a common substrate shown at 55 in FIG. 51 for an embodiment without an intermediate polarizer. A common substrate 55 is processed on both sides to provide the alignment and electrode layers 25, 26, 22 ', 23'. The color filters for the two LCDs are shown at 56,57.

  Alternatively or additionally, the intermediate substrate (s) can be formed from very thin glass. Suitable glasses are known as “microsheets” and are available from Scott, Germany.

  There are a variety of different pixel configurations that allow flexibility in the angle at which light of a particular color can pass through both LCDs. For example, the configuration shown in FIG. 50 may be used. For a 200 mm pixel pitch and 700 mm liquid crystal layer separation 44, light in the angular range of air from about 12 ° to about 61 ° passes through the color filters of the same color in layers 24 and 24 '. Although light from pixel 50 is passed by pixel 52 of the same color, there is a second range of angles where this light is totally reflected at the glass: air interface. By taking into account the interface effects between media of different refractive indices, it is possible to generate a configuration in which light that is not within the desired primary angular range is totally reflected to avoid undesirable visual effects. Become.

  In the configuration shown in FIG. 50, each of the liquid crystal layers is provided with the same type of filter, for example, so that each layer has red, green, and blue filters. However, LCDs can be provided with different color filtering, for example, filters for one LCD can include red, green and blue filters, but filters for other LCDs can include cyan, magenta, yellow filters.

  FIG. 52 shows another form of color filtering in which individual filters include horizontal strips extending across the width of the display. For example, as shown in FIG. 52, the color filter includes a group in which red 60, green 61, and blue 62 filters are repeated. The individual color filters for the two LCDs are arranged relative to each other such that the red filter for the upper LCD is directly above the red filter for the lower LCD. Thus, such an arrangement allows a wide range of viewing angles in the horizontal plane relative to the display for light transmission, but does not itself prevent light propagation at inappropriate angles.

  To avoid the need to consider the color filter geometry, the display can be implemented using time series color technology. In this case, a color filter is not necessary. This is because the LCD displays different color components in successive time frames or slots and a switched multi-color backlight is used. For example, the red, green and blue diodes are activated periodically using colored light emission to obtain a sufficiently high frame rate so that the color component image is confused by the human eye in a full color image A backlight may be formed.

  Alternatively, a color wheel configuration and a white light source may be used for this purpose. Such an arrangement is shown in FIG. 53 and includes display components 20 to 28, 21 'to 28' having a backlight in the form of a white light source 30a and a color wheel 30b. The wheel 30b includes equally sized sector shaped color filters, and the wheel is configured to rotate so that each filter in turn passes between the light source 30a and the other components of the display.

  As a further alternative, a color schooling band may be used to avoid color splitting problems that may be associated with time series color displays. Such a configuration is disclosed in Katoh et al., “A Novel High-Definition Projection System using Single CG-Silicon TFT-LCD and an Optical Image Shift Device”, LN-5, Euro2200.

  In such a time series color embodiment, only one color is displayed in each time slot, and the gray scale correction used in each time slot is different for each color to compensate for the chromatic dispersion of the LCD. obtain.

  In the embodiment described above, it is necessary to consider the influence of two LCDs that variably attenuate light passing through the display in two images. To reduce or avoid this difficulty, the two LCDs may be configured to manually function as two spatial phase modulators between the polarizers shown in FIG. In this configuration, the LCD includes a spatial phase modulator SPM 170 and a modulator 171 disposed between the polarizer 20 and the polarizer 28 ', where the modulator 170 and the modulator 171 are designated a to 1. Pixelated to provide pixels. The display then provides spatial phase modulation, thereby intensity modulation passing through the display in a first direction (eg, R1 and R2) and in a second direction (eg, L1 and L2). Can be controlled. In particular, by appropriately controlling the modulator 170 and the modulator 171, light propagating in the first direction and the second direction can be modulated independently of each other. Both images are formed with the same spatial resolution as that of the modulator 170 and the modulator 171, respectively.

  Light propagating in the direction L1 with respect to the “left” image and passing through the pixel b also passes through the pixel c. The resulting intensity is a combination of phase changes caused by pixel b and pixel c. Similarly, light propagating in the direction L2 has an intensity resulting from a combination of phase changes caused by the pixels d and e. For the “right” image, the light propagating in directions R1 and R2 is affected by the combination of phase changes caused by pixel b and pixel a and pixels d and c, respectively. Each pixel can provide a range of phase changes substantially over 180 °.

  It is necessary to select a boundary condition for a direction for either the first pixel or the last pixel of each of modulator 170 and modulator 171. This allows each image pixel intensity to be controlled independently of each other by solving a sufficiently large set of simultaneous equations. For example, for the propagation paths L1, L2, R1, and R2 shown in FIG. 54, the generated light intensity (I) can be expressed as the following simultaneous expression.

I (R1) = C (A (a) + A (b))
I (R2) = C (A (c) + A (d))
I (L1) = C (A (b) + A (c))
I (L2) = C (A (d) + A (e))
Here, A is a phase change caused by each pixel, and C is a constant. The value of the phase change can be formed so that the intensities of the two displayed images can be selected independently of each other.

  The above set of simultaneous equations includes four equations with five variables. However, the pixel a is a terminal pixel of the modulator 170, and is different from the pixel c that controls the phase of light passing in two directions, for example, and is necessary to change the movement of light passing in a certain direction. If, for example, providing a nominal black pixel for the left image, the pixel can be set to a (boundary) value for the left image. In this case, the phase change A (a) of the pixel may be set to nπ (where n is an integer). This provides a fifth equation, whereby a set of simultaneous equations can be solved for the fifth variable.

  The phase change is preferably optimized for the angle at which light passes through the liquid crystal layer in order to take into account the viewing angle depending on the three layers. The phase change is also preferably optimized for the wavelength of light passing through the liquid crystal layer. This may be the same or different for each LCD used. Its performance is preferably optimized for a particular angular viewing position and is substantially correct for a range of viewing angles.

  The separation between viewing areas can be changed by changing the distance between the LCDs.

  The pixel pitch may be adjusted to constitute a viewing window to be correctly formed.

  There may be opaque areas of “black mask” between the pixels of the LCD. A wide black mask may be used to increase the size of the viewing window so that the inaccurate angular range in which image data is displayed is substantially blocked.

  For example, as shown in FIG. 55, different combinations of pixels may be used to change the angle between the viewing directions for the two views being displayed. To increase the angular separation in the viewing direction, each pixel of each modulator does not cooperate with the nearest pixel of the other pixels, but instead cooperates with the next nearest pixel. Therefore, the intensity of a pixel in the right image is determined by the influence of pixels c and f, not pixels c and d as shown in FIG. In fact, switching between different angles of this view separation can be done electrically by changing the angular range over which the modulator 170 and modulator 171 are optimized.

  FIG. 56 shows how extensive angular ranges can be obtained by using time multiplexing and directional backlights. A directional backlight (not shown) is such that it provides illumination only at certain different angular ranges at different times.

  For example, as shown at the top of FIG. 56, during time frame 1, the backlight is set to only illuminate the view in the direction of right image 1 and left image 2. During this frame, the modulator 170 and the modulator 171 operate according to the operation shown in FIG. During the next time frame 2, the backlight is set to only illuminate the view in the direction of right image 2 and left image 1. During this time frame, modulator 170 and modulator 171 operate as shown in FIG.

  Such a configuration can show four views in different viewing directions. This may be used to provide a multiple view display or to form a dual autostereoscopic 3D display. As a further alternative, such a configuration may be used to increase the viewing range of a dual view display where the right images 1 and 2 are the same and the left images 1 and 2 are the same.

  Alternatively, the views may be displayed in a different order, for example as shown in FIG.

  Such a configuration may be used in the alternating high resolution single view mode shown in FIG. The light for each image pixel passes through the respective pixels of modulator 170 and modulator 171. Unlike the boundary pixels of modulator 170 and modulator 171, each pixel modulates light for two image pixels. The simultaneous equations described above may be set up so that all image pixels can be controlled independently of each other. An observer viewing the display from within the normal incidence angle range sees an image that doubles the spatial resolution of each of modulator 170 and modulator 171.

  Correct viewing of the image occurs within a predetermined angular range, eg, near normal incidence viewing of the display. In order to increase the angular range, a scatterer or diffuser 175 may be placed in front of the display as shown in FIG. The scatterer 175 may be switchable to a non-scattering mode to return to multiple view mode operation.

  FIG. 60 illustrates the operation of the alternating time series switching mode that does not require simultaneous equations to be solved. In each time frame, one LCD displays an image and the other LCD is switched to a uniform configuration, such as a uniform retarder or homeotropic layer. Each LCD displays its image in alternating time frames. Thus, as shown in FIG. 60, in an odd numbered time frame, one LCD displays an image that appears in the first viewing phrase but appears black in the second viewing direction. In the even numbered time frame, the other LCD displays an image that appears in the second viewing phrase but appears black in the first viewing direction. By selecting a sufficiently high frame rate, the images are fused by the viewer at each viewing.

  The LCD may or may not have a polarizer between them. The LCD operates in a liquid crystal mode such as normally black, normally white TN, normally white or normally black TVAN (twisted vertical alignment nematic). For example, FIG. 61 shows gray scale as applied voltage and transmittance for different viewing angles for a TVAN LCD with 90 ° twist and no polarizer. FIG. 62 shows the effect of the polarizer during 90 ° twisted TVAN.

  There must be consideration to avoid a situation where there is a polarizer between the LCDs and one LCD is switched to not transmit enough light for the image produced by the other LCD to be viewed.

  In another single view mode of operation, for substantially normal incidence viewing, one LCD may remain switched to function as a uniform layer, and its image is displayed by the other LCD. May be displayed. The uniform layer may have a substantially planar arrangement when the LCD functions as a uniform retarder, may be substantially panotropic, or switched to a state between these two. Also good. 61 and 62 show the performance when an LCD that does not display an image is substantially homeotropic with respect to the 0 ° marked curve.

  When using a display in single view time series mode, the plane on which the image is generated is different from the two LCDs that form the image. As a result, when the observer changes the position, parallax occurs between the images. This problem can be overcome or reduced by using the switchable scatterers described above or by using the switchable lens shown in FIG. The display shown in FIG. 63 includes a backlight in the form of a light source 180 and a collimator 181. The switchable lens device 182 is disposed between the collimator 181 and the LDCs 170 and 171, and as shown in FIG. 63, the right part and the left part, respectively, the inactive mode in the first time frame, the second mode It is possible to switch between active modes in the time frame. In the active mode, the lens device 182 is aligned with the adjacent media so that it does not substantially affect the light collimated from the collimator 181. In active mode, alignment is disabled so that the lens functions as a focusing lens.

  In the first time frame, LCD 170 displays an image for normal incidence viewing and LCD 171 functions as a uniform retarder. In the second time frame, the lens 182 is activated to converge the LCD 171 pixels in the same plane that the LCD 170 pixels were converged in the previous time frame. Here, the LCD 170 functions as a uniform retarder. Thus, the image is formed in the same plane as both types of time frames so as to avoid parallax problems.

  FIG. 64 shows that at 183, LCDs 170 and 171 are arranged substantially parallel to each other as in the embodiment described above. For each LCD that has a relatively large optimal viewing angle (eg, 30 °) from the normal to the device, this provides a relatively large angular separation between viewing angles. However, if it is desired to use this type of LCD to reduce the difference between the optimal viewing angles, the LCDs are oriented non-parallel to each other as shown at 184 in FIG. Also good. In this example, the LCDs 170 and 171 are rotated by 5 ° in opposite directions in the horizontal plane towards their respective normals. Thus, the angle between the optimal viewing directions is reduced from 60 ° to 50 °.

  FIG. 65 shows a dual view display that can be used to form two pairs of autostereoscopic images in a first viewing direction and a second viewing direction so that the display functions as a dual autostereoscopic display. . The display differs from the embodiment described above primarily or solely in that a parallax barrier 185 is disposed between the LCDs. The parallax barrier 185 functions as a rear parallax barrier for the LCD including the components 21, 24, 27, and functions as a front parallax barrier for the LCD including the components 21 ', 24', 27 '. Appropriate values for the parallax barrier pitch and the spacing of the parallax barrier 185 from each of the pixel planes in the liquid crystal layers 24 and 24 'are selected. Different pixel pitches may be required for the LCD. The operation of the front and rear parallax barrier autostereoscopic displays is well known and will not be further described.

  Any of the techniques described above with reference to FIGS. 10-15 may be applied to either or both displays 20-28 and 21-28 '.

  The voltage range selected to operate each LCD of the dual view display depends on the characteristics of the liquid crystal mode used. For example, each LCD can be driven with a different voltage range. Alternatively, both LCDs may be driven with substantially the same voltage range. Appropriate voltage ranges for dual view operation and, where appropriate, single view or dual autostereoscopic view modes are provided by the drive 29.

  The dual LCD embodiment described above is based on the TN and TVAN modes, but any liquid crystal mode that produces an appropriate asymmetric viewing angle may be used. For example, a suitable smectic or ferroelectric liquid crystal mode may be used. Further, other twisted nematic modes (for example, hybrid alignment nematic (HAN) mode) may be used.

  With the appropriate liquid crystal mode, each LCD of the display can have a different viewing angle. This can be adjusted for each specific application of the display. This increases the flexibility to obtain and adjust viewing angle characteristics. For example, each view may be optimized for different angles, which may be preferred in some applications, such as an automated application. By adjusting the gray scale used with the appropriate liquid crystal mode, the viewing angle that is optimized can be adjusted to be optimal for a particular viewer.

  An advantage of not using parallax optics or patterned layers is that no alignment step for the LCD is required. In general, arranging parallax optical elements or patterned layers on an LCD is time consuming and costly. With an additional uniform waveplate, pixel 1 presents an image in view 1, pixel 2 presents an image in view 2, and black in view 1 using an LC mode such as uniform TN or TVAN. A uniform LC panel can be made.

  FIG. 66 shows the layers forming the polarizer, LCD, etc. in an exploded view. Also shown are the vertical and horizontal directions relative to the vertical orientation of the display. The vertical upper reference direction is called 0 °, and the horizontal perpendicular direction is called 90 °. The various directions shown for the components shown in FIG. 66 are referred to as the upper vertical 0 ° direction.

  The front polarizer 20 has a transmission axis 30 oriented at an angle of + 90 ° with respect to the upper vertical. The alignment layer 23 has a uniform alignment direction 33 oriented at an angle of 0 ° with respect to the upper vertical. The alignment layer 25 has a uniform alignment direction 35 oriented at an angle of + 90 ° with respect to the upper vertical. The polarizer 28 has a transmission axis 38 that is oriented at an angle + 180 ° with respect to the upper vertical. The liquid crystal layer 24 is, for example, nematic liquid crystal available from Merck.

  The additional uniform wave plate 200 is disposed between the polarizer 200 and the liquid crystal layer 24. The uniform wave plate 200 has its optical axis 215 oriented at an angle of 315 ° with respect to the vertical direction above, has a birefringence of 494 nm, and its optical axis is 64 ° to the normal to the plane of the display. Inclined from the retarder plane at an angle. As a result, as shown in FIG. 67, display operation occurs in the viewing direction along the upper vertical direction at an angle of + 30 ° to −30 ° with respect to the normal to the plane of the display.

  FIG. 67 shows that there is a nearly uniform block state for the + 30 ° plot, where there is a range of brightness increase for −30 °, from the intersection of the two curves (about 1.5V) to about 4V. Show. This means that if the image can be presented at −30 °, a nearly constant black state is presented at + 30 °. From the intersection point at about 1.5V to 0.75V, there is a uniform black state for -30 °, but there is a range in which the luminance for + 30 ° increases. This means that the image can be presented at + 30 ° and a nearly constant black state is presented at -30 °. Thus, different high contrast images can be provided simultaneously in each viewing direction.

  The black state obtained in each state is a suboptimal black. The black state can be further optimized by variations in the properties of the waveplate. Alternatively, two wave plates may be used in combination. For example, the optical axes of the wave plates may be orthogonal to each other. By selecting the direction of the optical axis to be extended, one viewing plate may be optimized using one wave plate, and the other viewing direction may be optimized using the other wave plate. Alternatively, two viewing plates may be used to compensate for both viewing directions simultaneously. Alternatively, more than two wave plates may be used to compensate for different viewing directions. In addition to optimizing the black state, the color of the transmission may be compensated. Furthermore, the range of viewing angles that the system compensates for may also be optimized through the use of additional waveplates.

  The uniform wave plate may be a fixed layer such as a fixed retarder layer or a switchable layer such as a liquid crystal layer. A further advantage when the switchable layer is is that it provides a high contrast dual view image, thus providing a compensation layer to produce a more uniform viewing angle when used in 2D mode operation. It is to be switched to. This switching may be over the thickness of the cell or in a plane.

  Alternatively, two switchable viewing angle compensators may be used to generate a dual view display associated with an image providing an LCD. A switchable viewing angle compensator may be used in time series. In time frame 1, viewing angle compensator 1 compensates the pixels to provide view 1 with black and view 2 with an image. The viewing angle compensator 2 is switched to a configuration that does not affect the optical system. In time frame 2, viewing angle compensator 2 compensates the pixels to provide black for view 2 and an image for view 1. The viewing angle compensator 1 is switched to a configuration that does not affect the optical system. Alternatively, viewing angle compensators 1 and 2 can be switched between two configurations where the combined effect provides a high contrast ratio for each view. Viewing angle compensators 1 and 2 can also be switched to a third configuration that functions to produce an improved 2D mode.

  30 and 31 show the performance of a TVAN type display for viewing angles of −30 ° and + 60 °. 68 and 69 show the same display performance for -30 ° and + 30 ° viewing angles. Thus, the display can be used for substantial angular range operation.

  In the embodiment of FIGS. 4 and 5, the first pixel presents an image in view 1, presents black in view 2, the second pixel presents an image in view 2, and black in view 1. Present. The second pixel 2 can convert apparent white to black by using an additional switchable retarder, for example, as shown in FIG.

  If a large area of pixels is allocated as the first pixel and another large area is allocated as the second pixel, the switchable retarder is not a first pixel but a half-wave plate for the second pixel 2 May be switched to provide This converts the white from the second pixel to black and improves the contrast ratio. Since a large area is used, the parallax effect can be ignored, so there is no need to provide a switchable retarder in the LCD panel. The area may be user selectable and the area of the switchable retarder in that case needs to be selectively switchable. Pixels may be assigned to any view in any configuration and in any case. Alternatively, the pixels may be defined in advance, in which case a fixed retarder may be used.

  Various modifications may be made within the scope of the present invention. It includes:

  1. When there is a narrow viewing angle range with good image quality, tracking of each observer's eye position is performed, thereby driving the observer's eyes to stay in a region of good image quality The angle optimized by the change in can be adjusted.

  2. With regard to switching from dual view to 2D mode, using a TN or TVAN panel, the panel is rotated 90 ° so that the maximum asymmetric direction of the viewing angle is now vertical and the dual view compensation means is It can be switched off to provide maximum uniformity in the horizontal viewing direction.

  3. More than one gamma correction may be used.

  4). The number of gray levels does not necessarily have to change with respect to switching between dual view and 2D mode. The voltage range used for each gray level can instead be adjusted according to the same number of gray levels within the new voltage range. This provides the maximum number of gray levels in each case. However, this requires more complex drive and circuitry. Instead, the number of gray levels used is simply changed when switching between dual view and 2D mode, with no complex changes in drive and circuitry.

  5). A sensor may be used to detect whether the display operates in dual view or 2D mode. For example, if only one person can be detected in a vehicle, a 2D image may be provided to the occupant with maximum resolution. If the passenger is in the car and wants to see the email on the car panel, the display automatically switches to dual view mode so that the driver is not distracted.

  6). When time multiplexing is used, the brightness of each view is reduced. This can be compensated for by increasing the backlight brightness (eg, by using an alternative or additional backlight) when the panel is operated in dual view mode.

  7). A dual view display may efficiently switch to uniform mode operation by displaying the same image in each view. This reduces costs without the need for additional optical elements and complex driving.

  8). Appropriate holograms, cholesteric liquid crystals or lenticulars may be used to reduce crosstalk.

  9. A dual view display may be provided using a standard LCD with a parallax barrier. However, when using a parallax barrier with an LCD in this embodiment, it is advantageous that the optical properties of the panel are optimized for off-axis dual view position rather than normal incidence. Thus, improvements in brightness and crosstalk for each viewer can be made compared to standard LCDs and parallax barriers.

  10. A switchable scattering layer or diffuser (eg, polymer dispersed liquid crystal) may be used to switch between dual view mode and 2D mode operation.

  11. More than two panels (eg, four panels) may be used to provide a multi-view display of the type described above. By using additional panels, the resolution can be increased. The panel may be patterned or uniform.

  12 A reflective or transflective LCD panel with asymmetric scattering or reflection points may be used to control the viewing angle direction.

  13. If regions of different thickness are formed, a suitable polymer may be coated onto the substrate in a simultaneous step and the grid array surface may be embossed in the polymer.

  14 In order to obtain the maximum number of gray levels, it is necessary to maximize the voltage range where the pixels for view 1 provide an image for view 1 while appearing dark in view 2 (and vice versa). . The minimizing voltage that increases with each gray level is determined in part by the drive technique used and also limits the number of gray levels.

  15. A parallax barrier may also be used with embodiments having a patterned liquid crystal configuration.

  According to the present invention, a multiple view display (eg, a dual view display) is provided for displaying unrelated images in different viewing areas. The display comprises a liquid crystal display device (20-28) having pixels (101, 102) with asymmetric viewing angle characteristics. The display also comprises a drive device (29) for driving the pixels for displaying the first image in the first viewing direction and displaying the second image in the second different viewing direction. The pixel (101) displaying the first image appears dark in the second direction, and the pixel (102) displaying the second image appears dark in the first direction.

FIG. 1 is a diagram illustrating the use of a multiple view display. FIG. 2 is a diagram illustrating the use of a multiple view display. FIG. 3 is a diagram illustrating the use of a multiple view display. FIG. 4 is a cross-sectional view of a display constituting the embodiment of the present invention. FIG. 5 is an exploded view showing the orientation of the components of the display of FIG. FIG. 6 is a polar diagram showing the display contrast ratio at different viewing angles. FIG. 7 is a graph of viewing angle and intensity for different gray levels of the display of FIG. FIG. 8 is a graph of gray level and intensity at two different viewing angles. FIG. 9 is a graph of voltage and brightness showing two different voltage ranges. FIG. 10 is a graph of gray level versus intensity for different viewing angles and different pixel colors. FIG. 11 is a graph of image gray levels and corrected gray levels showing the results of gray scale correction for different colors. FIG. 12 is a cross-sectional view of a display constituting another embodiment of the present invention. FIG. 13 is a cross-sectional view of a display constituting a further embodiment of the present invention. FIG. 14 shows a cross-sectional view illustrating a method of creating a pixelated retarder. FIG. 15 is a graph of voltage and transmittance for two different viewing directions. FIG. 16 is a diagram showing a temporal multiplexing mode of operation of the display. FIG. 17 is a diagram showing a spatial and temporal multiplexing mode in which the operations of the display are combined. FIG. 18 is a graph of luminance against applied voltage indicating an idealized display driving method. FIG. 19 is a cross-sectional view of a display constituting a further embodiment of the present invention. FIG. 20 shows a graph of voltage and transmittance to illustrate the operation of the display of FIG. FIG. 21 shows a graph of voltage and transmittance for illustrating the operation of the display of FIG. FIG. 22 shows a diagram of a portion of a display that constitutes a further embodiment of the invention, with a graph of voltage and transmittance showing its operation. FIG. 23 is a graph of transmittance versus voltage for single view mode operation of the display of FIG. FIG. 24 shows a diagram of a part of still another display constituting the embodiment of the present invention, and a graph of voltage and transmittance showing the operation thereof. FIG. 25 is a graph of transmittance and voltage illustrating the operation of the display of FIG. 25 in single view mode. FIG. 26 is a cross-sectional view of a display constituting still another embodiment of the present invention. FIG. 27 is a diagram showing displays of different sizes and their viewing conditions. FIG. 28 is a cross-sectional view of a display constituting an embodiment of the present invention. FIG. 29 is an exploded view showing the orientation of the components of the display of FIG. FIG. 30 illustrates voltage and luminance in transmission for the device configuration. FIG. 31 illustrates the voltage and luminance in transmission for the device configuration. FIG. 32 illustrates the variation of the luminance ratio along with the voltage. FIG. 33 is an exploded view showing the orientation of the components of the display. FIG. 34 illustrates voltage and luminance in transmission for the device configuration. FIG. 35 illustrates the voltage and luminance in transmission for the device configuration. FIG. 36 illustrates the variation of the luminance ratio along with the voltage. FIG. 37 shows a dual display usage pattern. FIG. 38 illustrates the use of polymer walls to separate different LC materials. FIG. 39 illustrates the operation of a dual display having a central crosstalk region. FIG. 40 illustrates the operation of the dual display along with the use of the central crosstalk region. FIG. 41 illustrates the use of four device configurations. FIG. 42 illustrates the use of four device configurations. FIG. 43 is a cross-sectional view of a display constituting the embodiment of the present invention. 44 is an exploded view showing the orientation of the components of the display embodiment of FIG. FIG. 45 is a graph of voltage and transmittance for the LCD of the display of FIG. FIG. 46 is a graph of voltage and transmittance for the LCD of the display of FIG. FIG. 47 is a graph of voltage versus transmittance for a display of the type shown in FIG. 43, omitting the intermediate polarizer. FIG. 48 shows two graphs similar to FIG. 9 showing the driving method for the LCD of the display of FIG. FIG. 49 illustrates a display having a single set of color filters and constituting an embodiment of the present invention. FIG. 50 shows a display having two sets of color filters and constituting an embodiment of the present invention. FIG. 51 is a cross-sectional view of a display constituting another embodiment of the present invention. FIG. 52 shows an example of a pixel and color filter configuration. FIG. 53 shows a time-series display constituting the embodiment of the present invention. FIG. 54 is a cross-sectional view of a display constituting a further embodiment of the present invention. FIG. 55 shows an alternate mode of operation of the display of FIG. FIG. 56 shows a time series mode of operation of the display of FIG. FIG. 57 shows a time series mode of operation of the display of FIG. FIG. 58 illustrates the high resolution single view mode operation of the display of FIG. FIG. 59 shows a modification of the mode shown in FIG. FIG. 60 shows the operation in the time series mode. FIG. 61 shows two graphs of voltage and transmission for a display including two TVAN LCDs without an intermediate polarizer. FIG. 62 shows two graphs of voltage and transmission for a display including two TVAN LCDs with intermediate polarizers. FIG. 63 shows a display with a further time series mode of operation. FIG. 64 shows the use of an angled or non-parallel LCD to adjust the angle between viewing directions. FIG. 65 shows a cross-sectional view of a display including a parallax barrier constituting another embodiment of the present invention. 66 is a view similar to FIG. 5 showing the orientation of the components of the display making up the embodiment of the present invention. FIG. 67 is a graph of voltage and luminance showing the operation of the display of FIG. FIG. 68 is similar to FIGS. 30 and 31 for different viewing angles. FIG. 69 is similar to FIGS. 30 and 31 for different viewing angles.

Claims (80)

  At least one liquid crystal display device (20-28, 21'-28 ') comprising a plurality of pixels (101, 102) having asymmetric viewing angle characteristics, and a first image in a first viewing direction (1) And a driving device (29) for driving the pixels to display a second image in a second direction (2) different from the first viewing direction (1), the driving device (29) wherein the at least one display device is such that pixels displaying the first image appear dark in the second direction and pixels displaying the second image appear dark in the first direction. Multi-view display in cooperation with (20-28, 21'-28 ').   Pixels (101, 102) displaying said first image and said second image appear maximally dark in said second direction and said first direction (2, 1), respectively. Multi-view display as described. The intensity of light supplied in the second direction and the first direction (2, 1) by the pixels (101, 102) for displaying the first image and the second image, respectively, is And the pixels (101, 102) for displaying the second image are more than X% of the maximum intensity of light that can be supplied in each of the first direction and the second direction (1, 2). The multi-view display of claim 2, wherein X is a real number less than 20, wherein X is less than 20. The multi-view display of claim 3, wherein X is equal to 10. The multi-view display of claim 3, wherein X is equal to 3.5. The multi-view display according to claim 3, wherein X is equal to one.   The multi-view display according to claim 1, wherein the first image and the second image are independent of each other.   The first direction and the second direction are perpendicular to the display surface of the at least one device (20-28, 21'-28 ') and in a plane that includes the direction of maximum viewing angle asymmetry. The multi-view display according to any one of claims 1 to 6. The multi-view display according to claim 8, wherein the first direction and the second direction (1, 2) are on the side corresponding to a normal to the display surface. The multi-view display according to claim 9, wherein the first direction and the second direction (1, 2) are substantially symmetric with respect to the normal. The multi-view display according to claim 9, wherein the first direction and the second direction (1, 2) are asymmetric with respect to the normal.   The pixels displaying the first image are configured to provide a first contrast ratio greater than 1 in the first direction and provide a contrast substantially equal to 1 in the second direction; The pixel displaying a second image is configured to provide a second contrast ratio in the second direction and provide a contrast substantially equal to 1 in the first direction. The multi view display in any one of -11. The multi-view display according to claim 1, wherein an angle between the first direction and the second direction may be substantially equal to or greater than 10 °.   The at least one device (20-28, 21'-28 ') may comprise a set of pixels, each set of pixels being the same color and a different color than the other set of pixels. The multi view display in any one of 1-13. 15. The multi-view display according to claim 14, wherein the at least one device (20-28, 21'-28 ') comprises liquid crystal layers having different thicknesses (46) in different color pixels. 16. The at least one device (20-28, 21'-28 ') comprises a patterned retarder (50) in which regions of different retardations are optically arranged for pixels of different colors. Multi-view display as described in The multi-view display according to claim 16, wherein the different retardation regions include different color pigments for functioning as a color filter. 18. Multi-view display according to any of the preceding claims, wherein the at least one device (20-28, 21'-28 ') is a transmissive mode device. The at least one display device (20-28, 21′-28 ′) has an asymmetric liquid crystal mode having uniform alignment and asymmetric viewing angle characteristics, and the driving device (29) displays the first image. At least one of a first driving method (40) for displaying and a second driving method (41) different from the first driving method (40) for displaying the second image. The multi-view display according to any of the preceding claims, configured to drive a device (20-28, 21'-28 '). The multi-view display according to claim 19, wherein the first driving scheme and the second driving scheme include a first voltage range and a second voltage range (40, 41) which are different from each other. The multi-view display according to claim 19 or 20, wherein the liquid crystal mode is any one of twist nematic, hybrid alignment nematic, and twist vertical alignment nematic. 22. The first view and the second view according to any of claims 19 to 21, wherein the first view and the second view are spatially multiplexed with the at least one device (20-28, 21'-28 '). Multi-view display. The at least one device includes a liquid crystal layer (24) and at least one uniform retarder (200) disposed between the uniform input polarizer and the output polarizer (20, 28). Multi-view display as described. The retarder (200) is oriented substantially 45 ° in the plane of the retarder (200) with respect to one transmission axis (30) adjacent to the polarizing plate (20), and is perpendicular to the plane of the retarder. 24. A multi-view display according to claim 23, having an optical axis oriented substantially at 67 [deg.] Relative to. The multi-view display of claim 24, wherein the retarder has a retardation of substantially 494 nm. The at least one device (20-28, 21'-28 ') includes a patterned polarizer (28) having a first region and a second region for a first view and a second view, respectively. The multi-view display according to claim 22, wherein the transmission axis of the first region is different from the transmission axis of the second region. 27. The multi-view display according to claim 26, wherein the transmission axis of the first region is substantially perpendicular to the transmission axis of the second region. The multi-view display according to claim 22, wherein the at least one device (20-28, 21'-28 ') comprises a patterned retarder. 29. The multi-view display of claim 28, wherein the patterned retarder is switchable to substantially zero retardation for single view mode operation. 30. A multi-view display according to any of claims 22 to 29, wherein the at least one device (20-28, 21'-28 ') comprises a parallax barrier (95).   31. A method according to any of claims 19 to 30, wherein the first view and the second view are temporally multiplexed in the at least one device (20-28, 21'-28 '). Multi-view display. 30. A multi-view display according to claim 29, wherein the at least one device (20-28, 21'-28 ') comprises a switchable retarder (80). The multi-view display according to claim 32, wherein the retardation of the retarder (80) is switchable between odd and even half-waves of visible light. The at least one device (20-28, 21′-28 ′) includes a first pixel (101) having a first configuration of a first asymmetric viewing angle characteristic, and a first asymmetric viewing angle characteristic. A second pixel (102) having a second configuration different from the first configuration of a second asymmetric viewing angle characteristic that is oriented differently from the first configuration, 19. The device according to claim 1, configured to drive the first pixel for displaying one image and the second pixel for displaying the second image. Multi-view display. The first image and the second image are seen in a third viewing direction (115) between the first direction and the second direction (1, 2). Multi-view display as described. 36. A multi-view display according to claim 34 or 35, wherein the first pixels (101) are spatially distributed to the second pixels (102). 37. A multi-view display according to any of claims 34 to 36, wherein the first asymmetric viewing characteristic and the second asymmetric viewing characteristic are oriented in substantially opposite directions. The multi-view display according to any one of claims 34 to 37, wherein the first pixel and the second pixel (101, 102) have a first liquid crystal mode and a second liquid crystal mode which are different from each other. The multi-view display according to claim 38, wherein at least one of the first mode and the second mode is any one of twisted nematic, hybrid aligned nematic, twisted vertically aligned nematic, Frederix, vertically aligned nematic and pi-cell. . 40. A multi-view display according to claim 38 or 39, wherein the first pixel and the second pixel (101, 102) have different liquid crystal director twists in the absence of an applied electric field. 41. The multi-view display of claim 40, wherein the different twists have different sizes. 42. A multi-view display according to claim 40 or 41, wherein the different twists have different twist effects. 43. A multi-view display according to any of claims 40 to 42, wherein one of the different twists is 0 [deg.].   44. The multi-view display according to claim 38, wherein the first pixel and the second pixel (101, 102) have different liquid crystal director pretilts at at least one liquid crystal substrate interface. 45. The multi-view display of claim 44, wherein the different pretilts have different sizes. 46. A multi-view display according to claim 44 or 45, wherein the different pretilts have different directors.   47. A multi-view display according to any of claims 38 to 46, wherein the first pixel and the second pixel (101, 102) have different liquid crystal director orientations. 48. A multi-view display according to any of claims 38 to 47, wherein the first pixel and the second pixel (101, 102) have different surface anchor strengths at at least one liquid crystal substrate interface. 49. A multi-view display according to any of claims 38 to 48, wherein the first pixel and the second pixel (101, 102) comprise different liquid crystal materials. 50. At least one of the first pixel and the second pixel (101, 102) comprises a liquid crystal material comprising at least one of a chiral dopant, a polymer network and a dye. Multi-view display. 51. The multi-view display according to claim 38, wherein the first pixel and the second pixel have liquid crystal layers having different thicknesses. The first pixel (101) has a polarizer whose transmission axis is oriented at a first angle with respect to the liquid crystal optical axis of the first pixel (101), and the second pixel (102). 52. A second polarizer according to claims 38 to 51, wherein the second polarizer has a transmission axis oriented at a second angle different from the first angle with respect to the liquid crystal optical axis of the second pixel (102). A multi-view display according to any one of the above. 53. A multi-view display according to any of claims 34 to 52, wherein the first pixel and the second pixel (101, 102) have a first retarder and a second retarder with different retardations.   54. The multi of any of claims 34 to 53, wherein the first pixel and the second pixel (101, 102) have a first compensation layer and a second compensation layer that provide different compensation effects. View display. The multi-view according to any of claims 34 to 54, wherein the driving device (29) is configured to drive the first pixel and the second pixel (101, 102) in different voltage ranges. display. 56. A multi-view display according to any of claims 34 to 55, wherein said at least one device (20-28, 21'-28 ') comprises a parallax barrier (95). 57. A multi display as claimed in any of claims 34 to 56, wherein the display comprises a further liquid crystal device (122) which can be displayed through the previous device (122) and is configured to operate in time sequence. View display. The at least one device is oriented differently than the first liquid crystal device (20-28) having a first asymmetric liquid crystal mode with a first asymmetric viewing characteristic. And a second liquid crystal device (21′-28 ′) having a second asymmetric liquid crystal mode having a second asymmetric viewing characteristic, wherein the driving device (29) displays the first image. The first drive method (40) of the first device (20-28) is driven, and the second drive method for displaying the second image is (41) the second device (21′- The multi-view display according to any of the preceding claims, configured to drive 28 '). 59. The multi-view display according to claim 58, wherein the first driving scheme and the second driving scheme each include a first voltage range and a second voltage range (40, 41), respectively. 60. The multi-view display of claim 59, wherein the first voltage range and the second voltage range are substantially the same. 61. A multi-view display according to any of claims 58 to 60, wherein the second device (21'-28 ') is viewed via the first device (20-28). 62. A multi-view display according to claim 61, wherein the second device (21'-28 ') is arranged between the first device (20-28) and a backlight (30).   63. A multi-view display according to any of claims 58 to 62, wherein the first device and the second device (20-28, 21'-28 ') are substantially parallel to each other. 64. A multi-view display according to any of claims 58 to 63, wherein each of the first device and the second device (20-28, 21'-28 ') has a uniform arrangement. 65. A multi-view display according to any of claims 58 to 64, wherein each of the first device and the second device (20-28, 21'-28 ') is a transmissive mode device. 66. A multi-view display according to any of claims 58 to 65, wherein the first liquid crystal mode and the second liquid crystal mode are of the same type. 67. A multi-view display according to any of claims 58 to 66, wherein the first asymmetric viewing characteristic and the second asymmetric viewing characteristic are oriented in substantially opposite directions. 68. The first device and the second device (20-28, 21'-28 ') have an array oriented in substantially opposite directions, according to any of claims 58 to 67. Multi-view display. 69. The multi-view according to claim 58, wherein at least one of the first liquid crystal mode and the second liquid crystal mode is one of twist nematic, hybrid alignment nematic, and twist vertical alignment nematic. display. The at least one device (20-28, 21'-28 ') includes a set of pixels, each set of pixels being the same color and a color different from the other set of pixels;
70. A multi-view display according to any of claims 58 to 69, wherein each of the first device and the second device (20-28, 21'-28 ') comprises a set of pixels of different colors. One of the first device and the second device (20-28, 21′-28 ′) includes a set of red, green, and blue pixels, and the first device and the second device ( The multi-view display of claim 70, wherein the other of 20-28, 21'-28 ') comprises a set of cyan, magenta, and yellow pixels. The first device and the second device (20-28, 21′-28 ′) have color filter stripes extending substantially parallel to a plane including the first direction and the second direction ( The multi-view display according to claim 70 or 71, comprising: 60-62). The display includes a multi-color time series backlight (30a, 30b), and the driving device (29) colors the first device and the second device (20-28, 21′-28 ′). 70. A multi-view display according to any of claims 58 to 69, configured to drive in a time series of: The driving device (29) supplies temporally multiplexed images to the first device and the second device (20-28, 21′-28 ′), and synchronously switches the direction switchable backlight. 74. A multi-view display according to any of claims 58 to 73, wherein the multi-view display is configured to control the display. 75. A multi-view display according to any of claims 58 to 74, wherein each of the first device and the second device (20-28, 21'-28 ') comprises a spatial phase modulator. 76. A switchable light scatterer switchable between a substantially non-scattering state for a multiple view mode of the display and a scattering mode for a single view mode of the display. A multi-view display according to any one of the above.   A liquid crystal display device (20-28) having an asymmetric liquid crystal mode having uniform alignment and asymmetric viewing angle characteristics, and a first driving method for displaying a first image in a first viewing direction (1) ( 40) and a second different from the first driving scheme (40) for displaying a second image in a second direction (2) different from the first viewing direction (1). A multi-view display comprising: a driving device (29) that drives the device (20-28) by a driving method (41).   A first pixel (101) having a first configuration of a first asymmetric viewing angle characteristic and a second asymmetric viewing angle characteristic oriented differently than the first asymmetric viewing angle characteristic; A liquid crystal device (20-28) including a second pixel (102) having a second configuration different from the first configuration, and a first image in a first viewing direction (1). Driving the first pixel (101) for display and displaying the second image (102) in a second viewing direction (2) different from the first viewing direction; And a driving device (29) for driving two pixels (102).   A liquid crystal device comprising a first pixel (101) having a first configuration with a first asymmetric viewing angle characteristic and a second pixel (102) having a second configuration different from the first configuration (20-28), driving the first pixel (101) to display the first image in the first viewing direction and the second viewing direction (115), And a driving device (29) for driving the second pixel (102) to display a second image in the viewing direction (2).   A first liquid crystal device (20-28) having a first asymmetric liquid crystal mode with a first asymmetric viewing angle characteristic and a second asymmetric oriented differently from the first asymmetric viewing angle characteristic A second liquid crystal device (21′-28 ′) having a second asymmetric liquid crystal mode with viewing angle characteristics, and a first driving scheme for displaying a first image in a first viewing direction; Driving the first device (20-28) and displaying the second image in a second viewing direction different from the first viewing direction in the second driving manner in the second device And a driving device (29) for driving (21'-28 ').

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