Directional display device

Abstract

The switchable privacy display includes an emissive SLM, a parallax barrier, a switchable LC retarder, and a passive retarder disposed between parallel output polarizers. In the privacy mode, on-axis light from the SLM is guided losslessly, while the parallax barrier and retarder layers cooperate to increase the VSL for off-axis snoops. The display can be rotated to achieve privacy operation in both landscape and portrait orientations. In the public mode, the LC retardation is adjusted such that the off-axis brightness increases, thus increasing image visibility for multiple users. The display can also be switched between day operation and night operation, for example for automotive environments. The low-reflectivity emissive display for ambient lighting includes an SLM with emissive pixels, an absorptive parallax barrier, and a hyperspectral leakage optical isolator. The front light from the pixels is guided with increased transmittance efficiency, while the ambient light is strongly absorbed.

Description

Technical Field

[0001] The present disclosure generally relates to illumination from a light modulation device, and more particularly, to an optical stack for providing control of illumination used in a display including a privacy display and a night display. Background Art

[0002] A privacy display provides image visibility to a primary user (typically located at an on-axis position) and reduces the visibility of the image content to a snoop (typically located at an off-axis position). The privacy function can be provided by a microshutter optical film that transmits some light in the on-axis direction from the display and low luminance at off-axis positions. However, such films have high losses for front illumination, and due to pixel jitter of the spatial light modulator, the microshutters may cause Moiré artefacts. The pitch of the microshutters may need to be selected for the panel resolution, thereby increasing inventory and cost.

[0003] A switchable privacy display can be provided by controlling off-axis optical output.

[0004] Control can be provided by means of luminance reduction, for example by means of a switchable backlight for a liquid crystal display (LCD) spatial light modulator. Display backlights typically employ waveguides and edge-emitting sources. Some imaging directional backlights have the additional ability to direct illumination through the display panel to the viewing window. An imaging system can be formed between multiple sources and corresponding window images. An example of an imaging directional backlight is an optical valve that can employ a folded optical system and can thus also be an example of a folded imaging directional backlight. Light can propagate through the optical valve with substantially no loss in one direction, and the light propagating in the reverse direction can be extracted by reflecting the tilted facets, as described in U.S. Patent No. 9,519,153, which is incorporated herein by reference in its entirety. Summary of the Invention

[0005] According to a first aspect of the present disclosure, there is provided a display device including: a transmissive spatial light modulator including a pixel array arranged in a pixel layer; a parallax barrier that forms an array of holes, wherein the parallax barrier is spaced from the pixel layer by a parallax distance along an axis normal to the plane of the pixel layer; and each pixel is aligned with a hole. The parallax barrier can direct light from each pixel into a common viewing window. Advantageously, a full-resolution image with a low reflectivity and reduced off-axis luminance can be achieved.

[0006] Along the direction in which the holes are closest, the holes have a width a and the pixels have a width w, which can satisfy the requirement a≥w. Advantageously, full luminance can be achieved in at least one viewing direction.

[0007] Along the direction closest to the hole, the hole has a width a, the pixels have a pitch p, and the pixels have a width w, which can meet the requirement a ≤ (p - w / 2). Advantageously, for at least one viewing direction, the off-axis brightness can be reduced to at most 50%.

[0008] The parallax barrier has a spacing d from the pixels, the pixels have a pitch p along the direction closest to the hole, and the material between the parallax barrier and the pixels has a refractive index n, which can meet the requirement The direction of the minimum brightness can be at least 45 degrees to advantageously achieve the desired off-axis brightness for a privacy display.

[0009] The parallax barrier has a spacing d from the pixels, the hole has a width a along the direction closest to the hole, and the material between the parallax barrier and the pixels has a refractive index n, which can meet the requirement Provide at most 50% brightness at a polar angle of 90 degrees to advantageously achieve the desired off-axis brightness for a privacy display.

[0010] The parallax barrier has a spacing d from the pixels, the hole has a width a along the direction closest to the hole, and the material between the parallax barrier and the pixels has a refractive index n, which can meet the requirement Provide at most 50% brightness at a polar angle of 60 degrees to advantageously achieve the desired off-axis brightness for a privacy display.

[0011] The pitch p' along the direction closest to the hole can be less than the pitch p of the corresponding aligned pixels along the direction closest to the pixels; and the viewing window can be formed at the viewing window plane on the output side of the spatial light modulator. Advantageously, it increases the brightness uniformity for front-facing display users.

[0012] The parallax barrier can form a two-dimensional array of holes, with each pixel aligned with a corresponding hole. A reduction in brightness for side and elevation angles can be achieved. Advantageously, it can provide lateral and longitudinal privacy operations for a privacy display. The display reflectivity can be reduced and the display efficiency in the front direction can be improved.

[0013] The pixels can be arranged in columns and rows, the direction closest to the hole can be 45 degrees relative to the electric vector transmission direction of the output linear polarizer; and each pixel can have a square-shaped light-emitting region, where the edges are rotated 45 degrees relative to the electric vector transmission direction of the output linear polarizer. The hole can have a square shape, where the edges are rotated 45 degrees relative to the electric vector transmission direction of the output linear polarizer, or the hole can have a circular shape. Advantageously, a uniform brightness attenuation and brightness reduction at high polar angles can be achieved along the lateral and elevation azimuth directions.

[0014] For at least some of the pixels, the light-emitting region may include a light-emitting sub-region and a non-light-emitting sub-region. For red, green, and blue pixels, the area ratio of the light-emitting sub-region to the non-light-emitting region may be different. The color pixels can be driven with a similar drive voltage to achieve an output luminance that matches that provided by pixels in a display that does not provide a parallax barrier. Advantageously, the control and driver electronics reduce complexity and improve efficiency.

[0015] The parallax barrier can form a one-dimensional array of holes, with the pixels arranged in columns, and each pixel column aligned with a corresponding hole. Modifications to the pixel arrangement can be reduced, thereby reducing costs. Each pixel can have a light-emitting region that extends in the direction in which the holes extend; the widths of the red, green, and blue light-emitting regions can be the same for each pixel; and the heights of the light-emitting regions can be different for the red, green, and blue light-emitting pixels. The display can be conveniently rotated about an axis in one direction to advantageously provide a comfortable viewing height for a front observer. The yield and cost of aligning the parallax barrier can be reduced.

[0016] The parallax barrier can be arranged to absorb light incident thereon. Display reflections can be reduced, thereby advantageously increasing the display contrast in a brightly lit environment.

[0017] The absorption rate of the parallax barrier region between the holes can be less than 100% and can be greater than 80%, preferably greater than 90% and more preferably greater than 95%. Compared with a parallax barrier having a 100% absorption rate in the absorption region, the off-axis image visibility of the display can be increased.

[0018] The display device can be used for ambient lighting, and the parallax barrier can absorb at least some of the ambient lighting that is transmitted through the holes and reflected from the pixel layer. Reflections are reduced, thereby advantageously increasing the observed image contrast.

[0019] The display device can have one or more additional layers between the pixel layer and the parallax barrier, where the pixels, the one or more additional layers, and the parallax barrier can be formed as a monolithic stack. Advantageously, the separation of the pixel layer and the parallax barrier layer can have high stability during the applied mechanical force.

[0020] The one or more additional layers can include at least one light-transmissive inorganic layer arranged to provide a barrier against water and oxygen. The parallax barrier can include at least one light-transmissive inorganic material arranged to provide a barrier against water and oxygen. The parallax barrier can be arranged between the pixel layer and at least one light-transmissive inorganic layer arranged to provide a barrier against water and oxygen. Advantageously, the lifespan of the display can be increased.

[0021] The output polarizer can be arranged on the output of the spatial light modulator, and the output polarizer is a linear polarizer; and the reflection control quarter-wave retarder can be arranged between the output polarizer and the spatial light modulator. Advantageously, reflections from the pixel layer can be reduced.

[0022] The parallax barrier can be arranged between the pixel layer and the reflection control quarter-wave retarder. Advantageously, a small gap between the pixel layer and the parallax barrier can be conveniently achieved.

[0023] The display device can further include an additional polarizer arranged on the output side of the output polarizer, the additional polarizer being a linear polarizer; and at least one polarity control retarder arranged between the output polarizer and the additional polarizer. A privacy display with a high visual safety level can be advantageously provided.

[0024] When crossed with a conceptual polarizer of the same material, the transmittance of at least one of the output polarizer and the additional polarizer for wavelengths from 520 nm to 560 nm can be less than the transmittance for wavelengths from 450 nm to 490 nm. The transmittance for wavelengths from 450 nm to 490 nm can be greater than 1%, preferably greater than 2% and most preferably greater than 3%; and the transmittance for wavelengths from 520 nm to 560 nm can be less than 3%, preferably less than 2% and most preferably less than 1%. Compared with a broadband absorption polarizer, the transmittance of the display can be increased. Advantageously, the display efficiency is increased. For blue wavelengths, the transmittance may be relatively large. Advantageously, the lifespan of the display can be increased.

[0025] At least one polarity control retarder can further include at least one passive retarder.

[0026] At least one polarity control retarder may be capable of simultaneously performing the following operations: not introducing a net relative phase shift to the orthogonal polarization components of the light transmitted by the output polarizer along the axis normal to the plane of at least one polarity control retarder, and introducing a relative phase shift to the orthogonal polarization components of the light transmitted by the reflection polarizer along the axis inclined to the normal of the plane of at least one polarity control retarder. At least one passive retarder can include a retarder having an optical axis perpendicular to the plane of the retarder, and the retardation of the at least one passive retarder for light with a wavelength of 550 nm is in the range of -150 nm to -900 nm, preferably in the range of -200 nm to -500 nm and most preferably in the range of -250 nm to -400 nm. A large off-axis polar region with reduced brightness can be achieved. Advantageously, for many snooper positions, the visual safety level is high.

[0027] At least one retarder may include: a first quarter-wave plate and a second quarter-wave plate disposed between an additional polarizer and an output polarizer, the first quarter-wave plate being disposed on the input side of the second quarter-wave plate and being arranged to convert the polarization state of linearly polarized light transmitted by the output polarizer on its input side into a circularly polarized state, and the second quarter-wave plate on the output side being arranged to convert the polarization state of circularly polarized light incident thereon into a linearly polarized state transmitted by the additional polarizer on its output side; and at least one retarder disposed between the pair of quarter-wave plates. The retarder disposed between the pair of quarter-wave plates may include a retarder having an optical axis perpendicular to the plane of the retarder, and the at least one passive retarder has a retardation for light with a wavelength of 550 nm in the range of -150 nm to -500 nm, preferably in the range of -200 nm to -400 nm and most preferably in the range of -250 nm to -350 nm. A rotationally symmetric polar brightness reduction curve may be provided. Advantageously, the privacy display may be operated in both transverse and longitudinal modes. High visual security can be obtained for a snooper looking down from above the user's head.

[0028] At least one polarization control retarder may include a switchable liquid crystal (LC) retarder, the switchable liquid crystal retarder including a liquid crystal material layer and electrodes arranged to apply a voltage to switch the liquid crystal material layer. At least one polarization control retarder may be arranged to simultaneously perform the following operations in a first switchable state of the switchable liquid crystal retarder: not introducing a net relative phase shift to the orthogonal polarization components of light transmitted by a reflective polarizer along an axis normal to the plane of at least one polarization control retarder, and introducing a net relative phase shift to the orthogonal polarization components of light transmitted by the reflective polarizer along an axis inclined to the normal of the plane of at least one polarization control retarder; and simultaneously perform the following operations in a second switchable state of the switchable liquid crystal retarder: not introducing a net relative phase shift to the orthogonal polarization components of light transmitted by the reflective polarizer along an axis normal to the plane of at least one polarization control retarder, and not introducing a net relative phase shift to the orthogonal polarization components of light transmitted by the reflective polarizer along an axis inclined to the normal of the plane of at least one polarization control retarder. Advantageously, the display may be switched between a privacy operation mode and a public operation mode. An area that provides high visual security to off-axis snoopers in the privacy mode and high image visibility to off-axis users in the public mode is extended. The front user sees the image with high efficiency and high image visibility in both modes.

[0029] The display device may further include a reflective polarizer disposed between the output polarizer and at least one polarization control retarder, the reflective polarizer being a linear polarizer arranged to transmit a polarization component of the same linear polarization as the output polarizer. In the privacy operation mode, the privacy display may have a high reflectivity. In the privacy mode, a visual safety level can be maintained for various ambient lighting conditions. In the public mode, the display reflectivity is reduced to achieve high image visibility for various viewing positions.

[0030] The output polarizer may be a reflective polarizer. Advantageously, the display efficiency can be increased. Compared with a display without a parallax barrier, the display reflectivity can be reduced.

[0031] The pixel may include a light-emitting diode. Advantageously, high luminous efficiency, high contrast, and high brightness can be achieved through a wide color gamut.

[0032] The light-emitting diode may be an organic light-emitting diode including an organic light-emitting material. Advantageously, a thin and stable display can be provided. For each of the red, green, and blue light-emitting regions, the thickness of the light-emitting material may be different. For all colors, the pixel size may be nominally the same, such that the color attenuation is substantially the same for all polar angles. The cost and complexity of the driving electronics can be reduced.

[0033] At least some of the light-emitting diodes may be inorganic micro light-emitting diodes. Advantageously, extremely high brightness can be achieved. The barrier layer for water and oxygen can be omitted, thus advantageously reducing the cost. A larger area can be provided between the micro LEDs. Advantageously, the reflectivity of the pixel layer can be reduced. A leakage polarizer can be provided for the switchable privacy display to achieve increased output efficiency.

[0034] The hole has an absorption rate, and at the edge of the hole, the absorption rate may have a transmittance gradient, and the transmittance gradient has a transmittance gradient width greater than 1 micron, preferably greater than 2 microns, and more preferably greater than 3 microns. The diffraction effect can be reduced to advantageously achieve increased uniformity. The brightness attenuation curve may have an increased polar width to improve the uniformity for off-axis use.

[0035] The hole array may be formed on the touch sensor electrode array. At least one absorption region of the parallax barrier may include the touch sensor electrode array. Advantageously, a low-reflectivity touch electrode can be conveniently provided.

[0036] At least some of the holes of the parallax barrier may include color filters. The holes of the parallax barrier include an array of red, green, and blue color filters. Advantageously, the cross-interference between adjacent pixels can be reduced. The color gamut can be increased.

[0037] According to a second aspect of the present disclosure, a method of forming a display device is provided. The method includes the steps of: forming an emission pixel array on a backplane by guiding an emission material through a fine metal mask, the fine metal mask forming an encapsulation layer including at least one transparent inorganic layer on the emission pixel array; forming a parallax barrier including a hole array on a surface of the encapsulation layer by guiding a light absorption material through a fine metal. Advantageously, the same equipment used for forming an OLED display can be used to form the parallax barrier, thereby reducing costs.

[0038] According to a third aspect of the present disclosure, a method of forming a display device is provided. The method includes the steps of: forming an emission pixel array on a backplane by guiding an emission material through a fine metal mask, the fine metal mask forming an encapsulation layer including at least one transparent inorganic layer on the emission pixel array; forming a parallax barrier including a hole array on a surface of the encapsulation layer by photolithographic patterning. Advantageously, an accurate parallax barrier can be conveniently aligned with the pixel layer.

[0039] According to a fourth aspect of the present disclosure, a reflectivity control display device for ambient lighting is provided. The reflectivity control display device includes the display device of the first aspect, wherein the parallax barrier absorbs at least some of the ambient lighting. Advantageously, the output efficiency can be increased while maintaining or reducing the display reflectivity.

[0040] Any aspect of the present disclosure can be applied in any combination.

[0041] Embodiments of the present disclosure can be used in various optical systems. The embodiments can be incorporated or used with a variety of projectors, projection systems, optical components, displays, microdisplays, computer systems, processors, self - contained projector systems, visual and / or audiovisual systems, and electrical and / or optical devices. In fact, various aspects of the present disclosure can be used with any device related to optical devices and electrical devices, optical systems, presentation systems, or any device that can contain any type of optical system. Therefore, embodiments of the present disclosure can be used in optical systems, devices for visual and / or optical displays, visual peripherals, etc., as well as in a variety of computing environments.

[0042] Before entering into the detailed disclosed embodiments, it should be understood that the present disclosure is not limited in its application or creation to the details of the specific settings shown, as the present disclosure is capable of having other embodiments. In addition, the aspects of the present disclosure can be presented in different combinations and settings to define unique embodiments in terms of their own rights. Moreover, the terms used herein are for the purpose of description and not limitation.

[0043] By reading the entire content of the present disclosure, these and other advantages and features of the present disclosure will become apparent to those of ordinary skill in the art. Description of the Drawings

[0044] In the drawings, embodiments are illustrated by way of example, where like reference numerals indicate like parts, and where:

[0045] Figure 1A FIG. 8A is a schematic side perspective view of a switchable privacy display for ambient lighting, the switchable privacy display including an OLED emitting spatial light modulator, a parallax barrier, an output polarizer and a reflective control quarter-wave retarder, a reflective polarizer, a switchable polarity control retarder, and an additional polarizer disposed on the output side of the spatial light modulator;

[0046] Figure 1B FIG. 8B is a front view showing Figure 1A the alignment of the optical layers in the optical stack of;

[0047] Figure 2A and 2B FIG. 8C is a side view showing the parallax barrier for a Figure 1A privacy display of -B;

[0048] Figure 3A FIG. 8D is a schematic side perspective view showing the alignment of the parallax barrier with the Figure 1A pixels for non-pupil output;

[0049] Figure 3B FIG. 8E is a schematic side perspective view showing the alignment of the parallax barrier with the Figure 1A pixels for pupil output;

[0050] Figure 4 FIG. 8F is a top view showing the arrangement of uniform emission pixels and eye point positions for various polarization perspectives;

[0051] Figure 5 FIG. 8G is a top view showing the arrangement of structured emission pixels and eye point positions for various polarization perspectives;

[0052] Figure 6 FIG. 8H is a side view showing the structure of the spatial light modulator and the aligned parallax barrier including an upper incident reduction layer;

[0053] Figure 7 FIG. 8I is a side view showing the structure of the spatial light modulator and the aligned parallax barrier including a glass cover layer;

[0054] Fig. 8A 、 8B and 8C are schematic views showing the variation of the parallax barrier transmittance with the position of various parallax barrier structures;

[0055] Fig. 9A diagram showing the arrangement of the switchable retarder in the common mode in a perspective side view, where the switchable retarder includes a horizontally aligned switchable LC layer and a crossed A-plate polarization control retarder;

[0056] Fig. 10A A schematic diagram showing the propagation of the output light from the spatial light modulator through Figure 1A the optical stack in the common operating mode in a side view;

[0057] Fig. 10B A schematic diagram showing the propagation of the light rays from the ambient light source through Figure 1A the optical stack in the common operating mode in a side view;

[0058] Fig. 10C A schematic diagram showing the propagation of the output light from the spatial light modulator through Figure 1A the optical stack in the privacy operating mode in a side view;

[0059] Fig. 10D A schematic diagram showing the propagation of the light rays from the ambient light source through Figure 1A the optical stack in the privacy operating mode in a side view;

[0060] Fig.11A Is Figure 1A A polar plot array of the component ratios and outputs of the arrangement, including the spatial light modulator brightness, parallax barrier transmittance, switchable retarder transmittance, switchable retarder reflectance, common mode brightness, privacy mode brightness, and a polar plot for the visual safety level at a lux / nt ratio of 1.0;

[0061] Fig. 11B Is Fig.11A A linear graph array of the component ratios and outputs of the arrangement, including linear graphs at azimuth angles of 0 degrees (east direction), 90 degrees (north direction), 45 degrees (northeast direction), and 225 degrees (southwest direction);

[0062] Fig. 11C Is for Fig.11A -B an illustrative embodiment with a lux / nt ratio of 0.25, a polar graph, and a linear polar graph;

[0063] Fig. 12A Is for an illustrative arrangement in which the parallax barrier is removed Figure 1A A polar plot array of the component ratios and outputs of the arrangement, including the spatial light modulator brightness, parallax barrier transmittance, switchable retarder transmittance, switchable retarder reflectance, common mode brightness, privacy mode brightness, and a polar plot of the visual safety level;

[0064] Fig. 12B Is Fig. 12A Component weight ratios and output linear graph arrays of the arrangement, including linear curves at azimuth angles of 0, 90, 45, and 225 degrees;

[0065] Fig.13A is for an illustrative arrangement where a switchable retarder is removed Figure 1A Component weight ratios and output polar graph arrays of the arrangement, including polar graphs of spatial light modulator brightness, parallax barrier transmittance, switchable retarder transmittance, switchable retarder reflectance, common mode brightness, privacy mode brightness, and visual safety level;

[0066] Fig. 13B is Fig.13A Component weight ratios and output linear graph arrays of the arrangement, including linear curves at azimuth angles of 0, 90, 45, and 225 degrees;

[0067] Fig.14 is a schematic diagram in side view illustrating the reflection of ambient light in a Figure 1A display;

[0068] Fig.15 is a schematic diagram illustrating the variation of output brightness with the wavelength of a broadband absorption polarizer and a leakage absorption polarizer;

[0069] Fig.16A is a schematic diagram illustrating the variation of polarizer transmittance with the wavelength of a broadband absorption polarizer and a leakage absorption polarizer and with respect to the Fig.14 spectral output of red, green, and blue emitting pixels of the transmitted light;

[0070] Fig. 16B is a schematic diagram illustrating the variation of reflectance with the wavelength of a broadband absorption polarizer and a leakage absorption polarizer and with respect to the Fig.14 spectral output of red, green, and blue emitting pixels of the reflected light;

[0071] Fig.17A is a schematic diagram in side perspective view illustrating a switchable privacy display for ambient lighting, including a micro LED emitting spatial light modulator, a parallax barrier, an output polarizer and a reflection control quarter-wave retarder, a passive polarity control retarder, a reflective polarizer, a switchable polarity control retarder, and an additional polarizer arranged on the output side of the spatial light modulator.

[0072] Fig. 17B is a schematic diagram in front view illustrating the Fig.17A alignment of optical layers in an optical stack;

[0073] Fig. 17CIt is a schematic diagram showing the arrangement of micro-LED emission pixels and eye point positions for various polar viewing angles in a top view;

[0074] Fig.17D It is a schematic diagram showing a passive polarizing control retarder arranged between an output polarizer and a reflective polarizer in a side perspective view;

[0075] Fig.18A It is a schematic diagram showing the structure of a spatial light modulator and an alignment parallax barrier including a vignetting parallax barrier hole in a side view;

[0076] Fig.18B 、 18C and 18D are schematic diagrams showing the variation of parallax barrier transmittance with the position of various parallax barrier structures;

[0077] Fig.19A is Fig.17A a polar plot array of the component ratios and outputs of the arrangement, including polar plots of spatial light modulator brightness, parallax barrier transmittance, passive polarizing control retarder, switchable retarder transmittance, switchable retarder reflectance, common mode brightness, privacy mode brightness, and visual safety level;

[0078] Fig.19B is Fig.19A a linear graph array of the component ratios and outputs of the arrangement, including linear curves at azimuth angles of 0, 90, 45, and 225 degrees;

[0079] Fig.19C is Fig.17A a polar plot array of the component ratios and outputs of the arrangement, including polar plots of spatial light modulator brightness, parallax barrier transmittance, passive polarizing control retarder, switchable retarder transmittance, switchable retarder reflectance, common mode brightness, privacy mode brightness, and visual safety level;

[0080] Fig.19D is Fig.19C a linear graph array of the component ratios and outputs of the arrangement, including linear curves at azimuth angles of 0, 90, 45, and 225 degrees;

[0081] Fig. 20A It is for an illustrative arrangement where the parallax barrier is removed Fig.17A a polar plot array of the component ratios and outputs of the arrangement, including polar plots of spatial light modulator brightness, parallax barrier transmittance, switchable retarder transmittance, switchable retarder reflectance, common mode brightness, privacy mode brightness, and visual safety level;

[0082] Fig. 20B is Fig. 20AArray of component ratios and output linear graphs of the arrangement, including linear curves at azimuth angles of 0, 90, 45, and 225 degrees;

[0083] Fig.21A is for an illustrative arrangement where the switchable retarder and the passive polarization control retarder are removed and the parallax barrier provides transmission in the light absorption region Fig.17A Array of component ratios and output polar graphs of the arrangement; including polar graphs of spatial light modulator brightness, parallax barrier transmittance, switchable retarder transmittance, switchable retarder reflectance, common mode brightness, privacy mode brightness, and visual security level;

[0084] Fig. 21B is Fig.21A Array of component ratios and output linear graphs of the arrangement, including linear curves at azimuth angles of 0, 90, 45, and 225 degrees;

[0085] Fig. 21C is for an illustrative arrangement where the switchable retarder and the passive polarization control retarder are removed and the parallax barrier does not provide transmission in the light absorption region Fig.17A Array of component ratios and output polar graphs of the arrangement; including polar graphs of spatial light modulator brightness, parallax barrier transmittance, switchable retarder transmittance, switchable retarder reflectance, common mode brightness, privacy mode brightness, and visual security level;

[0086] Fig.21D is Fig.21A Array of component ratios and output linear graphs of the arrangement, including linear curves at azimuth angles of 0, 90, 45, and 225 degrees;

[0087] Fig.22A is a schematic diagram showing the arrangement of the switchable retarder in the privacy mode in a perspective side view, where the switchable retarder includes a switchable LC layer with a horizontal alignment arranged between the C-plate passive polarization control retarders;

[0088] Fig. 22B is a schematic diagram showing the arrangement of the switchable retarder in the common mode in a perspective side view, where the switchable retarder includes a switchable LC layer with a horizontal alignment arranged between the C-plate passive polarization control retarders;

[0089] Fig.23A is a schematic diagram showing the arrangement of the retarder layer of a 270-degree supertwisted switchable liquid crystal retarder arranged between parallel polarizers and including a quarter-wave plate;

[0090] Fig. 23B is Fig.23AComponent ratios of the arrangement and output polar plot arrays, including spatial light modulator brightness, parallax barrier transmittance, switchable retarder transmittance, switchable retarder reflectance, common mode brightness, privacy mode brightness, and polar plots of visual safety levels;

[0091] Fig.23C is Fig. 23B Component ratios of the arrangement and output line graph arrays, including line graphs at azimuth angles of 0, 90, 45, and 225 degrees;

[0092] Fig.24A is a perspective view schematic illustrating the brightness appearance of a mobile device in common mode, including Figure 1A the display of Fig.23A and the polar control retarder of , whose appearance is shown in the order from upper left in a clockwise direction: front horizontal, front vertical, top-down vertical, and right-side horizontal;

[0093] Fig. 24B is a perspective view schematic illustrating the brightness appearance of a mobile device in privacy mode, including Figure 1A the display of Fig.23A and the polar control retarder of , whose appearance is shown in the order from upper left in a clockwise direction: front horizontal, front vertical, top-down vertical, and right-side horizontal;

[0094] Fig.24C is a perspective view schematic illustrating the reflectance appearance of a mobile device in privacy mode, including Figure 1A the display of Fig.23A and the polar control retarder of , whose appearance is shown in the order from upper left in a clockwise direction: front horizontal, front vertical, top-down vertical, and right-side horizontal;

[0095] Fig.25A is a top view schematic illustrating a motor vehicle with a switchable directional display arranged in a vehicle cockpit in a night operation mode;

[0096] Fig.25B is a side view schematic illustrating a motor vehicle with a switchable directional display arranged in a vehicle cockpit in a night operation mode;

[0097] Fig.26 is a side perspective view schematic illustrating a switchable privacy display for ambient lighting, including an OLED emission spatial light modulator, a one-dimensional parallax barrier, an output polarizer and a reflection control quarter-wave retarder, a reflection polarizer, a switchable polar control retarder, and an additional polarizer arranged on the output side of the spatial light modulator;

[0098] Fig. 27 is a front view illustrating Fig.26Schematic diagram of alignment of optical layers in an optical stack;

[0099] Fig.28 Schematic diagram in side perspective view of a switchable privacy display for ambient lighting, including a micro-LED emitting spatial light modulator, a parallax barrier, and an output polarizer as a reflective polarizer, a reflection control quarter-wave retarder, a switchable polarization control retarder, and an additional polarizer arranged on the output side of the spatial light modulator;

[0100] Fig.29 Schematic diagram in side view showing Fig.28 reflection of ambient light in the display of

[0101] Fig.30 Schematic diagram in side perspective view of a low-reflectivity display for ambient lighting, including an OLED emitting spatial light modulator, a two-dimensional parallax barrier, a leaky output polarizer, and a reflection control quarter-wave retarder arranged on the output side of the spatial light modulator;

[0102] Fig.31 Schematic diagram in side view showing Fig.30 reflection of ambient light in the display of

[0103] Fig.32 Schematic diagram in side perspective view of a touchscreen low-reflectivity display for ambient lighting, including an OLED emitting spatial light modulator, a two-dimensional parallax barrier including a touch sensor electrode layer, a leaky output polarizer, and a reflection control quarter-wave retarder arranged on the output side of the spatial light modulator;

[0104] Fig.33 Schematic diagram in front view showing Fig.32 reflection of ambient light in the display of

[0105] Fig.34 Schematic diagram in side view showing Fig.32 the structure of

[0106] Fig.35A Schematic diagram in side perspective view of a low-reflectivity display for ambient lighting, including an OLED emitting spatial light modulator, a two-dimensional parallax barrier and no output polarizer arranged on the output side of the spatial light modulator;

[0107] Fig.35B Schematic diagram in side view showing Fig.35A reflection of ambient light in the display of

[0108] Fig.36AA schematic diagram showing a low-reflectivity display for ambient lighting in a side perspective view, including an OLED emitting spatial light modulator, two one-dimensional parallax barriers, and no output polarizer arranged on the output side of the spatial light modulator;

[0109] Fig.36B A side view showing Fig.36A the reflection of ambient light in the display of

[0110] Fig.37A A side view showing an array of reflection and refraction optical elements arranged between the pixels of the spatial light modulator and the parallax barrier;

[0111] Fig.37B Showing the change of output brightness with Fig.37A the polar angle of the arrangement of

[0112] Fig.38A 、 38B 、38C and 38D are side views showing a method of manufacturing a parallax barrier of an emissive display using a fine metal mask;

[0113] Fig.39A 、 39B 、39C, 39D, 39E and 39F are side views showing a method of manufacturing a parallax barrier of an emissive display using photolithography;

[0114] Fig.40A 、 40B 、40C and 40D are side views showing a method of manufacturing a parallax barrier of an emitter using printing;

[0115] Fig.41 A side perspective view showing a switchable privacy display for ambient lighting, including an OLED emitting spatial light modulator containing tangible OLED pixels, an output polarizer, a reflection control quarter-wave retarder, a reflective polarizer, a switchable polarity control retarder, and an additional polarizer arranged on the output side of the spatial light modulator;

[0116] Fig.42 A side perspective view showing the pixels of an OLED emitting spatial light modulator, where the OLED pixels are tangible OLED pixels including a tangible well and a high refractive index filling material;

[0117] Fig.43 A side view showing a pixel of an OLED emitting spatial light modulator, where the OLED pixel includes a tangible well and a high refractive index filling material;

[0118] Fig.44It is a schematic diagram showing the change in the emission intensity of tangible and intangible OLED pixels;

[0119] Fig.45A It is Fig.41 a polar plot array of the component ratios and outputs of the arrangement, including the polar plots of spatial light modulator brightness, switchable retarder transmittance, switchable retarder reflectance, common mode brightness, privacy mode brightness, and visual safety level;

[0120] Fig.45B It is Fig.45A a linear graph array of the component ratios and outputs of the arrangement, including the linear graphs at azimuth angles of 0, 90, 45, and 225 degrees;

[0121] Fig.46 It is a schematic diagram showing a switchable privacy display for ambient lighting in a side perspective view, including an emissive spatial light modulator, a parallax barrier, a first polarization control retarder arranged between the display polarizer and the first additional polarizer of the emissive spatial light modulator; and a reflective polarizer and a second polarization control retarder arranged between the first additional polarizer and the second additional polarizer;

[0122] Fig.47A It is a schematic diagram showing the arrangement of polarizers and polarization control retarders for an embodiment of Fig.46 wherein the first and second polarization control retarders cross;

[0123] Fig.47B It is a graph showing the simulated polar curve of the brightness output of an emissive spatial light modulator without a barrier structure;

[0124] Fig.47C It is a graph showing the simulated polar curve of the transmittance of the barrier structure of light from the pixels of an emissive spatial light modulator;

[0125] Fig.47D It is a graph showing the simulated polar curve of the transmittance of the second polarization control retarder arranged between the first and second additional polarizers, Fig.47A wherein the transmission directions of the electric vectors of the polarizers are parallel;

[0126] Fig.47E It is a graph showing the simulated polar curve of the reflectance of the second polarization control retarder arranged between the reflective polarizer and the second additional polarizer, Fig.47A wherein the transmission directions of the electric vectors of the polarizers are parallel;

[0127] Fig.47F It is a graph showing the simulated polar curve of the total reflectance including Fig.47E the reflectance and the Fresnel reflectance from the front surface of the display device;

[0128] Figure 47G It is a graph of the simulated polarization curve of the transmittance of the first polarization control retarder disposed between the display polarizer and the first additional polarizer, where the electric vector transmission direction of the polarizer is parallel; Fig.47A It is a graph of the simulated polarization curve of the transmittance of the first polarization control retarder disposed between the display polarizer and the first additional polarizer, where the electric vector transmission direction of the polarizer is parallel;

[0129] Figure 47H It is an illustration of Fig.47A a graph of the simulated polarization curve of the logarithm of the total output luminance of the spatial light modulator and the first and second polarization control retarders;

[0130] Fig.47I It is an illustration of Fig.47A a graph of the simulated polarization curve of the safety level S for the ambient illuminance measured in lux in the privacy mode, where the ambient illuminance is twice the front display luminance measured in nits; and

[0131] Fig.47J It is an illustration of Fig.47A a graph of the simulated polarization curve of the safety level S for the ambient illuminance measured in lux in the public mode, where the ambient illuminance is twice the front display luminance measured in nits. Detailed Description

[0132] Terms related to optical retarders for the purposes of this disclosure will now be described.

[0133] In a layer including a uniaxial birefringent material, there is a direction that controls the optical anisotropy, and all directions perpendicular to it (or at a given angle to it) have equal birefringence.

[0134] The optical axis of an optical retarder refers to the direction of propagation of light in a uniaxial birefringent material that does not experience birefringence. This is different from the optical axis of an optical system, which can be parallel to a symmetry line or perpendicular to the display surface along which the chief ray propagates, for example.

[0135] For light propagating in a direction orthogonal to the optical axis, when linearly polarized light with an electric vector direction parallel to the slow axis propagates at the slowest speed, the optical axis is the slow axis. The slow axis direction is the direction with the highest refractive index at the design wavelength. Similarly, the fast axis direction is the direction with the lowest refractive index at the design wavelength.

[0136] For a positive dielectric anisotropy uniaxial birefringent material, the slow axis direction is the extraordinary axis of the birefringent material. For a negative dielectric anisotropy uniaxial birefringent material, the fast axis direction is the extraordinary axis of the birefringent material.

[0137] The terms half - wavelength and quarter - wavelength refer to the operation of the retarder for a design wavelength λ that typically can be between 500 nm and 570 nm. 0 In this illustrative embodiment, unless otherwise stated, exemplary retardance values are provided for a wavelength of 550 nm.

[0138] The retarder provides a phase shift between two perpendicular polarization components of the light wave incident thereon, and is characterized by the amount of relative phase Γ imparted on the two polarization components; the relative phase is related to the birefringence Δn and the thickness d of the retarder:

[0139] Γ = 2. π. Δn. d / λ 0 Equation 1

[0140] In Equation 1, Δn is defined as the difference between the extraordinary refractive index and the ordinary refractive index, i.e.,

[0141] Δn = n e - n o Equation 2

[0142] For a half - wave retarder, the relationship between d, Δn, and λ 0 is chosen such that the phase shift between the polarization components is Γ = π. For a quarter - wave retarder, the relationship between d, Δn, and λ 0 is chosen such that the phase shift between the polarization components is Γ = π / 2.

[0143] The term half - wave retarder in this article generally refers to light that is perpendicular to the retarder and perpendicular to the light propagating through the spatial light modulator.

[0144] Some aspects of the propagation of light through a transparent retarder between a pair of polarizers will now be described.

[0145] The state of polarization (SOP) of light is described by the relative amplitude and phase shift between any two orthogonal polarization components. The transparent retarder does not change the relative amplitude of these orthogonal polarization components, but only acts on their relative phase. Providing a net phase shift between the orthogonal polarization components changes the SOP, while maintaining the net relative phase preserves the SOP. In the current description, the SOP can be referred to as the polarization state.

[0146] A linear SOP has a polarization component with non - zero amplitude and an orthogonal polarization component with zero amplitude.

[0147] A linear polarizer transmits the only linear SOP of the linear polarization component with the electric vector transmission direction parallel to the linear polarizer and attenuates light with different SOPs.

[0148] An absorptive polarizer is a polarizer that absorbs one polarization component of incident light and transmits a second, orthogonally polarized component. An example of an absorptive linear polarizer is a dichroic polarizer.

[0149] A reflective polarizer is a polarizer that reflects one polarization component of incident light and transmits a second, orthogonally polarized component. Examples of reflective polarizers that are linear polarizers are multi-layer polymer film stacks such as the DBEF from 3M Corporation TM or the APF TM , or a wire grid polarizer such as the ProFlux from Moxtek TM . A reflective linear polarizer can further include a cholesteric reflective material and a quarter-wave plate arranged in series.

[0150] A retarder disposed between a linear polarizer and a parallel linear analyzing polarizer that does not introduce a relative net phase shift provides complete transmission of light in addition to residual absorption within the linear polarizer.

[0151] A retarder that provides a relative net phase shift between orthogonal polarization components changes the SOP and provides attenuation at the analyzing polarizer.

[0152] In the present disclosure, an "A plate" refers to an optical retarder utilizing a layer of birefringent material with its optical axis parallel to the plane of the layer.

[0153] A "positive A plate" is a positive birefringent A plate, i.e., an A plate with a positive Δn.

[0154] In the present disclosure, a "C plate" refers to an optical retarder utilizing a layer of birefringent material, the optical axis of which is perpendicular to the plane of the layer. A "positive C plate" is a positive birefringent C plate, i.e., a C plate with a positive Δn. A "negative C plate" is a negative birefringent C plate, i.e., a C plate with a negative Δn.

[0155] An "O plate" refers to an optical retarder utilizing a layer of birefringent material, the optical axis of which has a component parallel to the plane of the layer and a component perpendicular to the plane of the layer. A "positive O plate" is a positive birefringent O plate, i.e., an O plate with a positive Δn.

[0156] An achromatic retarder can be provided, where the material of the retarder has a retardation value Δn.d that varies with wavelength λ as

[0157] Δn.d / λ = κ Equation 3

[0158] where κ is substantially constant.

[0159] Examples of suitable materials include modified polycarbonates from Teijin Films. In this embodiment, an achromatic retarder can be provided to advantageously minimize color variations between a viewing direction at a polar angle with low brightness reduction and a viewing direction at a polar angle with increased brightness reduction, as described below.

[0160] Various other terms related to retarders and liquid crystals used in this disclosure will now be described.

[0161] The liquid crystal cell has a retardation given by Δn·d, where Δn is the birefringence of the liquid crystal material in the liquid crystal cell and d is the thickness of the liquid crystal cell, independent of the alignment of the liquid crystal material in the liquid crystal cell.

[0162] Horizontal alignment refers to the alignment of liquid crystals in a switchable liquid crystal display where the molecules are aligned substantially parallel to the substrate. Horizontal alignment is sometimes referred to as planar alignment. Horizontal alignment typically provides a small pretilt angle, such as 2 degrees, such that the molecules on the surface of the alignment layer of the liquid crystal cell are slightly tilted, as described below. The pretilt angle is set to minimize degradation during cell switching.

[0163] In this disclosure, vertical alignment is a state where rod-shaped liquid crystal molecules are aligned substantially perpendicular to the substrate. In discotic liquid crystals, vertical alignment is defined as a state where the axis of the columnar structure formed by discotic liquid crystal molecules is aligned perpendicular to the surface. In vertical alignment, the pretilt angle is the pretilt angle of the molecules close to the alignment layer and typically close to 90 degrees and can be, for example, 88 degrees.

[0164] In a twisted liquid crystal layer, a twisted structure (also referred to as a helical structure or helix) of nematic liquid crystal molecules is provided. The twist can be achieved by non-parallel alignment of the alignment layer. Additionally, a cholesteric dopant can be added to the liquid crystal material to break the degeneracy of the twist direction (clockwise or counterclockwise) and further control the twist pitch in the relaxed (usually undriven) state. A supertwisted liquid crystal layer has a twist greater than 180 degrees. The twisted nematic layer used in a spatial light modulator typically has a 90-degree twist.

[0165] Liquid crystal molecules with positive dielectric anisotropy are switched from a horizontal alignment (e.g., A-plate retarder orientation) to a vertical alignment (e.g., C-plate or O-plate retarder orientation) by an applied electric field.

[0166] Liquid crystal molecules with negative dielectric anisotropy are switched from a vertical alignment (e.g., C-plate or O-plate retarder orientation) to a horizontal alignment (e.g., A-plate retarder orientation) by an applied electric field.

[0167] Rod-shaped molecules have positive birefringence such that n e >n o , as described in Equation 2. Discotic molecules have negative birefringence such that n e <no 。

[0168] Positive retarders such as an A plate, a positive O plate, and a positive C plate can typically be provided by a stretched film or rod-shaped liquid crystal molecules. A negative retarder such as a negative C plate can be provided by a stretched film or disc-shaped liquid crystal molecules.

[0169] Parallel liquid crystal cell alignment means that the alignment direction of the horizontal alignment layer is parallel or more typically anti-parallel. In the case of pre-tilted vertical alignment, the alignment layer can have a substantially parallel or anti-parallel component. A liquid crystal cell with hybrid alignment can have a horizontal alignment layer and a vertical alignment layer. A twisted liquid crystal cell can be provided by alignment layers that do not have parallel alignment (e.g., oriented 90 degrees to each other).

[0170] The transmissive spatial light modulator can further include a retarder between the input display polarizer and the output display polarizer, for example, as disclosed in U.S. Patent No. 8,237,876, which is incorporated herein by reference in its entirety. Such a retarder (not shown) is in a different position from the passive retarder of the present embodiment. Such a retarder compensates for the contrast degradation at off-axis viewing positions, which is a different effect from the brightness reduction at the off-axis viewing positions of the present embodiment.

[0171] Terms related to the appearance of a privacy display will now be described.

[0172] The dedicated operating mode of the display is the mode in which the observer sees low contrast sensitivity such that the image is not clearly visible. Contrast sensitivity is a measure of the ability to distinguish different levels of brightness in a static image. Reverse contrast sensitivity can be used as a measure of visual security because a high visual security level (VSL) corresponds to low image visibility.

[0173] For a privacy display that provides an image to an observer, visual security can be given as follows:

[0174] VSL = (Y + R) / (Y - K) Equation 4

[0175] where VSL is the visual security level, Y is the brightness of the white state of the display at the snoop's viewing angle, K is the brightness of the black state of the display at the snoop's viewing angle, and R is the brightness of the reflected light from the display.

[0176] The panel contrast ratio is given by:

[0177] C = Y / K Equation 5

[0178] For a high-contrast optical LCD mode, the white state transmittance remains substantially constant with the viewing angle. In the contrast-reducing liquid crystal mode of the present embodiment, the white state transmittance typically decreases as the black state transmittance increases, such that

[0179] Y + K~P.L Equation 6

[0180] Then, the visual safety level can be further given as:

[0181]

[0182] where the off-axis relative luminance P is typically defined as a percentage of the frontal luminance L at the snooper angle, and the display can have an image contrast C, and the surface reflectivity is ρ.

[0183] The off-axis relative luminance P is sometimes referred to as the privacy level. However, such a privacy level P describes the relative luminance of the display at a given polar angle compared to the frontal luminance and is not a measure of the privacy appearance.

[0184] The display can be illuminated by a Lambertian ambient illuminance I. Thus, in a completely dark environment, a high-contrast display has a VSL of approximately 1.0. As the ambient illuminance increases, the perceived image contrast decreases, the VSL increases, and a private image is perceived.

[0185] For a typical liquid crystal display, for almost all viewing angles, the panel contrast C is above 100:1, allowing the visual safety level to approach:

[0186] VSL = 1 + I.ρ / (π.P.L) Equation 8

[0187] The perceived image security can be determined from the logarithmic response of the eye such that

[0188] S = log 10 (v) Equation 9

[0189] The required limit value of S is determined as follows. In the first step, a privacy display device is provided. The changes in the privacy level P(θ) of the display device at the polar viewing angle and the changes in the reflectivity ρ(θ) of the display device at the polar viewing angle are measured using a bright light measuring device. For example, a light source of a light box with a substantially uniform luminance is arranged to provide illumination from an illumination area, and the illumination area is arranged to irradiate the privacy display device along the incident direction so as to be reflected to the observer position at a polar angle greater than 0° with respect to the normal of the display device. Considering the change in the reflectivity ρ(θ), the change in the illuminance I(θ) of the substantially Lambertian emitting light box at the polar viewing angle is determined by measuring the change in the reflected luminance recorded at the polar viewing angle. The measurements of P(θ), r(θ), and I(θ) are used to determine the change in the safety factor S(θ) at the polar viewing angle along the zero elevation axis.

[0190] In a second step, a series of high-contrast images are provided on the privacy display, including (i) small text images with a maximum font height of 3 mm, (ii) large text images with a maximum font height of 30 mm, and (iii) moving images.

[0191] In a third step, each observer (with vision correction as appropriate for viewing at 1000 mm) views each image from a distance of 1000 mm and adjusts their polar angle at zero elevation until an image is not visible to one eye at a position near or on the centerline of the display. The polar position of the observer's eye is recorded. The safety factor at the said polar position is determined according to the relationship S(θ). For different images, various display brightnesses Y max , different light box illuminances I(q = 0), different background lighting conditions, and different observers, the measurements are repeated.

[0192] Based on the above measurements, S < 1.0 provides low or no visual safety, 1.0 ≤ S < 1.5 provides visual safety depending on the contrast, spatial frequency, and temporal frequency of the image content, 1.5 ≤ S < 1.8 provides acceptable image invisibility (i.e., no observable image contrast) for most images and most observers, and S ≥ 1.8 provides complete image invisibility independent of the image content for all observers.

[0193] Compared with the privacy display, the desired wide-angle display is easily observable under standard ambient illumination conditions. A measure of image visibility is the contrast sensitivity, such as the Michelson contrast, which is given by:

[0194] M = (I max - I min ) / (I max + I min ) Equation 10

[0195] And thus:

[0196] M = ((Y + R) - (K + R)) / ((Y + R) + (K + R)) = (Y - K) / (Y + K + 2.R) Equation 11

[0197] Therefore, the visual safety level (VSL) is equal to (but different from) 1 / M. In this discussion, for a given off-axis relative luminance P, the wide-angle image visibility W is approximately

[0198] W = 1 / VSL = 1 / (1 + I.ρ / (π.P.L)) Equation 12

[0199] In this discussion, assume a typical display spectral emitter that outputs a color (u w '+Δu', v w '+Δv') from the desired white point (u w ', v w '). The color change Δη can be determined by the CIELUV color difference metric and is given by:

[0200] Δη = (Δu' 2 +Δv' 2 ) 1 / 2 Equation 13

[0201] The reflective refraction element employs both refraction and reflection, which may be total internal reflection or reflection from a metallized surface.

[0202] The structures and operations of various directional display devices will now be described. In this specification, common elements have common reference numerals. Note that the disclosure regarding any element applies to each device in which the same or corresponding element is provided. Therefore, for the sake of brevity, such disclosures will not be repeated.

[0203] There is a need to provide a switchable privacy display using an emissive spatial light modulator.

[0204] Figure 1A FIG. is a schematic side perspective view of a switchable privacy display 100 for ambient lighting 604, including an OLED emissive spatial light modulator 48, a parallax barrier 700, an output polarizer 218, and a reflective control quarter-wave retarder 228, a reflective polarizer 302, a switchable polarity control retarder 300, and an additional polarizer 318 disposed on the output side of the spatial light modulator 48; and Figure 1B FIG. is a schematic front view illustrating Figure 1A the alignment of the optical layers in the optical stack.

[0205] The emissive spatial light modulator 48 includes an array of red, green, and blue pixels 220, 222, 224 disposed in a pixel layer 214 on a backplane substrate 212. The pixels are arranged to output light 400 along the output direction. The pixels 220, 222, 224 include light-emitting diodes, which are organic light-emitting diodes including an organic light-emitting material 232.

[0206] The regions 226 between the pixels 220, 222, 224 include control electronics, and for the OLED pixel layer 214, the regions 226 are typically reflective.

[0207] The parallax barrier 700 includes an array of holes 702 with light absorbing regions 704 therebetween. The parallax barrier 700 is arranged as a two-dimensional array of holes 702, with each pixel 220, 222, 224 aligned with a corresponding hole.

[0208] The parallax barrier 700 is arranged on the spacer layer 216, which provides a spacing from the pixel layer 214 at a parallax distance d along an axis 199 normal to the plane of the pixel layer 214.

[0209] The output polarizer 218 is arranged on the output of the spatial light modulator 48. The output polarizer 218 is a linear polarizer with an electric vector transmission direction 219. A reflective control quarter-wave retarder 228 with an optical axis direction 229 is arranged between the output polarizer 218 and the spatial light modulator 48. The retarder 228 can be provided by a stretched birefringent film such as polycarbonate. Advantageously, a low-cost retarder 228 can be provided.

[0210] In Figure 1A -B embodiments, the parallax barrier 700 is arranged between the pixel layer 214 and the reflective control quarter-wave retarder 228. In other embodiments (not shown), the quarter-wave retarder 228 can be formed by a layer formed between the pixel layer 214 and the parallax barrier 700. For example, such a retarder 228 can include a cured reactive liquid crystal cell liquid crystal layer. Advantageously, the retarder can have a thickness equal to or less than the required thickness d, as will be further described below.

[0211] An additional polarizer 318 is arranged on the output side of the output polarizer 218. The additional polarizer 318 is a linear polarizer. A polarity control retarder 300 is arranged between the output polarizer 218 and the additional polarizer 318. The output polarizer 218 and the additional polarizer 318 are arranged to pass through the polarization states of the respective linear polarizations.

[0212] The polarity control retarder 300 includes passive retarders 330A, 330B and a switchable liquid crystal retarder 301, which includes transparent substrates 312, 316 and a switchable liquid crystal layer 314. A voltage driver 350 can be used to select the operating mode and can be controlled by a controller 352.

[0213] Regarding Fig. 9 , Fig.17D , Fig.22A -B and Fig.23A Illustrative embodiments are described, as will be further described in detail below.

[0214] Figure 1AThe embodiment further includes a reflective polarizer 302 disposed between the output polarizer 218 and the at least one polarization control retarder 300. The reflective polarizer 302 is a linear polarizer having an electric vector transmission direction 303, and the polarizer is arranged to pass the polarization state of the same linear polarization as the output polarizer 218.

[0215] The structures and operations of the polarization control retarder 300 and the reflective polarizer 302 are described in more detail in U.S. Patent Publication No. 2019-0086706, U.S. Patent Publication No. 2019-0250458, U.S. Patent Publication No. 2018-0321553, U.S. Patent Publication No. 2020-0159055, and WIPO Publication No. WO 2018 / 208618, and all U.S. patent publications are incorporated herein by reference in their entirety. The polarization control retarder in this specification may be replaced by any of the polarization control retarders described therein.

[0216] Reference will be made hereinafter to Fig. 10A -D to further describe the operation of the switchable liquid crystal retarder. In the privacy operation mode, the at least one polarization control retarder 300 is capable of simultaneously performing the following operations: not introducing a net relative phase shift to the orthogonal polarization components of the light transmitted by the output polarizer 218 along the axis 199 normal to the plane of the at least one polarization control retarder 300, and introducing a relative phase shift to the orthogonal polarization components of the light transmitted by the reflective polarizer 302 along the axis 197 inclined to the normal of the plane of the at least one polarization control retarder 300. In the common operation mode, the at least one polarization control retarder 300 is capable of simultaneously performing the following operations: not introducing a net relative phase shift to the orthogonal polarization components of the light transmitted by the output polarizer 218 along the axis 199 normal to the plane of the at least one polarization control retarder 300, and substantially not introducing a relative phase shift to the orthogonal polarization components of the light transmitted by the reflective polarizer 302 along the axis 197 inclined to the normal of the plane of the at least one polarization control retarder 300.

[0217] When combined with the reflective polarizer 302, this phase control of the output light advantageously achieves a reduction in off-axis brightness and an increase in Figure 1A the off-axis reflectivity of the display in the privacy mode. In the common mode, high transmittance and low display reflectivity are achieved at various polar angles. In addition, in both operation modes, high transmittance and low reflectivity are achieved for on-axis display users. Advantageously, the display user sees a high-brightness and high-contrast image in both modes, while the off-axis snooper sees a high level of visual security in the privacy mode and the off-axis user sees high image visibility in the common mode.

[0218] The structure and operation of the parallax barrier 700 will now be described.

[0219] In emissive displays, high brightness is typically provided at high polar angles. For example, a typical emissive display such as an OLED display can provide a brightness greater than 25% of the front brightness at a polar angle of, for example, 60 degrees. A micro-LED display including inorganic LEDs can have a substantially Lambertian brightness output, so the brightness at 60 degrees can be close to 100% of the front brightness.

[0220] As will be described in Fig.11A -B, the polarization control retarder 300 is typically arranged to provide an optimal level of visual safety at the designed polarization positions. For example, this polarization position can be the + / -45 degree side angles and the 0 degree elevation angle. At a side angle with a 5-degree difference from the designed polarization position, the reduction in brightness and the increase in reflectivity are reduced.

[0221] There is a need to provide a switchable privacy display that has high visual safety in the privacy mode at polar angles greater than 45 degrees and high image visibility in the public mode at polar angles greater than 45 degrees. For high image visibility under typical ambient lighting conditions, the off-axis brightness can ideally be at least 2.5% and preferably at least 5% of the front brightness. For high image security under typical ambient lighting conditions, the off-axis brightness can ideally be less than 1% and preferably less than 0.5%. There will further be a need to provide low chromaticity variation at the polar viewing angles.

[0222] Figure 2A -B illustrates in a side view a schematic diagram of the parallax barrier 700 for the privacy display 100 of Figure 1A -B. Figure 2A -B illustrates a cross-section in the direction θ closest to the hole 702.

[0223] It can be assumed that the features of the arrangement not further discussed in detail Figure 2A-2B correspond to the features with equivalent reference numerals as discussed above, including any potential variations in the features.

[0224] For the purpose of description, the various output layers such as polarizers and retarders arranged at the output of the parallax barrier are indicated by the monolithic layer 110.

[0225] Through simulations of retarder stacks, parallax barriers, pixel arrangements, and experiments through the display optical stack, an ideal range for the parallax barrier structure has been established.

[0226] The light ray 710 guided along the axis 199 perpendicular to the spatial light modulator 48 is guided through the corresponding alignment holes 702 of width a. The hole size a is greater than the pixel width w to achieve 100% brightness in the front direction. Thus, along the direction closest to the hole 702, the hole 702 has a width a and the pixels 220, 222, 224 have widths w that satisfy the following requirements:

[0227] Equation 14: a ≥ w

[0228] Some of the light rays 726 are guided in an off-axis direction such that the brightness in the off-axis direction is reduced compared to the front brightness of the light rays 710. The minimum absorption rate provided by the parallax barrier is desirably 50%, such that along the direction closest to the aperture 702, the aperture 702 has a width a, the pixels 220, 222, 224 have a pitch p, and the pixels 220, 222, 224 have a width w that satisfies the following requirements:

[0229] Equation 15: a ≤ (p - w / 2)

[0230] Some of the light rays 712 from the pixels 220, 222, 224 can be incident on the lower side of the parallax barrier absorption region 704 and can be absorbed. When the light rays 712 from the center of the pixels are incident on the center of the absorption region 704, the minimum transmission angle is provided. The polar angle in air can be at least 45 degrees, such that along the direction closest to the aperture 702, the material between the parallax barrier 700 and the pixels 220, 222, 224 has a refractive index n that satisfies the following requirements:

[0231]

[0232] The light rays 716 incident on the edge of the absorption region of the parallax barrier 700 from the centers of the pixels 220, 222, 224 are at a polar angle in air at which the brightness is at most 50% of the front brightness. Desirably, (in air) is at most 90 degrees, and thus the parallax barrier has a spacing d from the pixels 220, 222, 224 that satisfies the following requirements:

[0233]

[0234] In other embodiments, the ideal angle of is preferably at most 60 degrees, and thus the parallax barrier has a spacing d from the pixels 220, 222, 224 that satisfies the following requirements:

[0235]

[0236] Table 1 gives illustrative dimensions in micrometers of a pixel pitch of 50 micrometers in the direction closest to the pixels, and a refractive index of 1.5 for the medium between the pixel layer 214 and the parallax barrier 700.

[0237]

[0238] Table 1

[0239] Accordingly, the thickness d of the parallax barrier separation layer 216 is approximately 30 μm. As will be further described below, such a thickness is typical of a typical encapsulation layer of an OLED panel. The parallax barrier 700 can be formed ideally close to the pixel layer 214 to advantageously achieve the desired performance of a switchable privacy display.

[0240] Table 2 illustrates the structure of a dual-view parallax barrier autostereoscopic display for the same pixel pitch and pixel width by comparison with an embodiment of the present invention, where pixel columns point to viewing windows, and each window provides a left-eye or right-eye image. An ideal thickness range is provided for a minimum window size of 60 mm, a maximum window size of 67 mm, a minimum viewing distance of 250 mm, and a maximum window distance of 700 mm.

[0241]

[0242] Table 2

[0243] Advantageously, compared with embodiments for autostereoscopic displays, embodiments of the present invention achieve increased brightness and lower thickness. The parallax barrier of an autostereoscopic display does not achieve the ideal brightness control characteristics of a privacy display.

[0244] Some light rays 714 can pass through the holes 702 at an angle greater than the critical angle and are thus totally internally reflected. Such light rays can be absorbed by the top of the parallax barrier absorption region 704. Other absorption mechanisms will be further discussed below.

[0245] The absorption region 704 can be partially absorbing. Due to the reduced absorption rate of the absorbing material, some light rays 712 can pass through the absorption region 704. Additionally or alternatively, the absorption region 704 can be disposed within the sub-holes 722, which are arranged to allow the propagation of the light rays 712. The sub-holes 722 can have sizes and densities arranged to provide a desired illumination distribution in a common operating mode.

[0246] In an illustrative example, the barrier region 704 can transmit 5% of the incident light rays by means of the sub-holes 722. For Lambertian emission pixels 220, 222, 224, the brightness at a 60-degree angle can be arranged to be 5% by controlling the density and size of the sub-holes 722 and the hole width for a given pixel pitch p and pixel size a. In the privacy mode, the brightness can be less than 1%. Advantageously, the image visibility in the common operating mode can be increased, while a high level of visual security can be achieved in the privacy mode by means of the polarization control retarder 300.

[0247] The arrangement of the parallax barrier pitch p' compared to the pixel pitch p will now be described.

[0248] Figure 3A is shown in a side perspective view for the parallax barrier 700 for non-pupil output and Figure 1ASchematic diagram of the alignment of pixels 220, 222, and 224.

[0249] The parallax barrier 700 guides light from each pixel 220, 222, 224 to a common viewing window 26. In Figure 3A it, the common viewing window is angled, in other words, the common sub-window 26 from each pixel overlaps with the aligned barrier holes 702 at infinity and is collimated. The window represents the angular distribution of light from each slit. Advantageously, this arrangement provides a spatial attenuation across the display 100 similar to that of the polarization control retarder 300 and polarizers 218, 318. For a moving observer, a natural variation in image uniformity across the display area is achieved, that is, the part of the display closest to the user appears the brightest.

[0250] Figure 3B is a side perspective view illustrating the alignment of the parallax barrier 700 for pupil output with Figure 1A the pixels 220, 222, 224. The pitch p' along the direction closest to the holes 702 is less than the pitch p of the corresponding aligned pixels 220, 222, 224 along the direction closest to the pixels 220, 222, 224. In any given direction, the pitch s' of the closest holes 702 is less than the pitch s of the corresponding aligned pixels 220, 222, 224.

[0251] The viewing window 26 is formed at a viewing window plane at a distance v, which is on the output side of the spatial light modulator 48, such that the common viewing window at the overlap of the viewing windows is at a finite distance. Advantageously, for a front observer located at the window plane, the brightness uniformity across the display area is increased.

[0252] At least some of the holes in the parallax barrier may include color filters 703R, 703G, 703B, so the holes in the parallax barrier include an array of red, green, and blue color filters. The color filters may correspond to the colors of the corresponding aligned pixels 220, 222, 224. The filters reduce color crosstalk, such as blue light leaking into the red pixel holes, thus advantageously achieving an increased color gamut.

[0253] Alternatively, only some of the holes 702 may include color filters. For example, the holes 702 corresponding to the red and green emitting pixels 220, 222 may include yellow transmission filters. In some embodiments, color emission may be achieved through, for example, a blue emitting pixel and color conversion materials aligned with the pixels 220, 222 to achieve a color output. The yellow filter in the holes 702 may provide absorption of residual blue light, thus advantageously achieving an increased color gamut.

[0254] The material of the color filter of the hole 702 may include a non-scattering or low-scattering material, so as to maintain the angular control function of the hole 702 and the absorption region 704.

[0255] It can be assumed that the features of the arrangement of -B correspond to the features with equivalent reference numerals as discussed above, including any potential variations in the features. Figure 3A -B's arrangement features correspond to those with equivalent reference numerals as discussed above, including any potential variations in the features.

[0256] Figure 4 It is a schematic diagram showing the arrangement of the uniform emission pixels 220, 222, 224 and the eye point positions 260, 262, 264 for various polar viewing angles in a top view.

[0257] The pixels 220, 222, 224 are arranged in columns and rows, and the direction closest to the hole 702 is 45 degrees relative to the electric vector transmission direction 219 of the output linear polarizer; and each pixel 220, 222, 224 has a light-emitting region in a square shape, where the edges are rotated 45 degrees relative to the electric vector transmission direction of the output linear polarizer.

[0258] The hole 702 has a square shape, where the edges are rotated 45 degrees relative to the electric vector transmission direction of the output linear polarizer.

[0259] The eye point positions 260, 262, 264 represent the images of the observer's pupils at the pixel layer 214 provided by the hole 702. The eye point position 260 represents the position of the pupil of a front observer. Since the point position 260 is larger than the size of the pixel, the observer sees the same brightness as the pixel brightness and achieves 100% brightness.

[0260] For the position 262, the observer's eyes are located in the display quadrant (with non-zero side angle and elevation angle) and have a minimum transmittance. For the position 262, the observer's eyes are positioned at zero elevation angle, with a lateral offset and have a minimum transmittance.

[0261] The eye point position 264 has a greater spacing from the on-axis position compared to the position 262, such that the minimum transmittance is in the quadrant rather than closest in the lateral direction. Advantageously, the suppression in the viewing quadrant can be optimized.

[0262] In addition, Figure 4 the pixel arrangement achieves an ideal presentation of horizontal and vertical lines while reducing the number of red and blue pixels compared to the number of green pixels.

[0263] Due to the different luminous intensities (lumen / mm 2 ) for the corresponding material systems, OLED displays typically provide different emission regions for red, green, and blue pixels. By means of Figure 4In comparison with the embodiments, when used with the two-dimensional array of holes 702, the pixels 220, 222, 224 of the present disclosure include emission regions having substantially the same area for all pixels. Advantageously, the variation of the white point with the viewing angle can be minimized.

[0264] It is necessary to compensate for the different luminous intensities of the red, green, and blue emitters in the OLED display to achieve the desired white point.

[0265] The luminous intensity of each pixel 220, 222, 224 can be changed by adjusting the drive current between different color pixels, thus maintaining the white point. Therefore, the green pixel 222 can have an emission area that is, for example, twice the emission area conventionally used. The drive currents of the green pixel 222 and the red pixel 220 can be reduced to achieve the desired white point.

[0266] It may be necessary to provide the same drive current as that used for a typical OLED display.

[0267] Figure 5 FIG. is a schematic diagram illustrating the arrangement of the structured emission pixels 220, 222, 224 and the eye point positions for various polar viewing angles in a top view.

[0268] For at least some of the pixels 220, 222, 224, the emission regions of at least some of the pixels include emission sub-regions 232R, 232G, 232B and non-emission sub-regions 234. For the red, green, and blue pixels 220, 222, 224, the area ratios of the emission sub-regions to the non-emission regions are different. For each pixel, the sub-regions 232R, 232G, 232B can be provided within the same area. The distribution of the sub-regions 232 and the size of the eye point 260 can be arranged to provide a substantially uniform attenuation of the luminance with the polar angle, so as to advantageously achieve a minimum change in the white point with the viewing angle; and the required drive current can be provided for each of the color pixels 220, 222, 224.

[0269] It can be assumed that the features of the Figures 4 to 5 arrangement not further discussed in detail correspond to the features with equivalent reference numerals as discussed above, including any potential variations in the features.

[0270] Now, the structure of the OLED display including the parallax barrier 700 will be described.

[0271] Figure 6 FIG. is a schematic diagram illustrating the structure of the spatial light modulator 48 and the aligned parallax barrier 700 including the upper incident reduction layers 750, 752 in a side view.

[0272] The pixel layer 214 is formed on a substrate 212 and includes a thin-film control circuitry 240, which includes thin-film transistors, capacitors, electrodes, and other electronic control components. The vias 242 provide connections to an electrode 230, which is typically reflective. Emission layers 232R, 232G, 232B are disposed between electron transport layers 236R, 232G, 232B and hole transport layers 238R, 238G, 238B. The transparent electrode 244 is arranged to provide an output-side electrical connection.

[0273] The emission layer thicknesses 233R, 233G, 233B and the electron transfer layer thicknesses 237R, 237G, 237B can be adjusted to provide suitable light output characteristics. For each of the red, green, and blue light-emitting regions in pixels 220, 222, 224, the thicknesses 233R, 233G, 233B of the light-emitting materials are different.

[0274] In another arrangement (not shown), the hole and electron transport layers 236, 238 can be alternately disposed below and above the emission region 232. The total thickness of the pixel layer 214 can typically be 1 micron or less, and thus the difference in the position of the emission layer 232 is small compared to the distance to the spacer layer 216.

[0275] The display 100 device has one or more additional layers 750, 752 in the spacer layer 216 disposed between the pixel layer 214 and the parallax barrier 700, where the pixels 220, 222, 224, the one or more additional layers, and the parallax barrier 700 are formed as a monolithic stack. The one or more additional layers include at least one light-transmissive inorganic layer 752, which is arranged to provide a barrier to water and oxygen. For example, the material 752 can be an oxide material such as SiOx.

[0276] The layer 750 can have an organic material. The substrate 212 can further have layers 750, 752 (not shown). The ingress of water and oxygen can be inhibited while maintaining a flexible display structure with desired mechanical properties. Advantageously, the display lifetime can be increased.

[0277] The total thickness d can be adjusted to advantageously achieve the desired brightness attenuation as described elsewhere herein.

[0278] The parallax barrier 700 further includes at least one light-transmissive inorganic material, which is arranged to provide a barrier to water and oxygen. Advantageously, the lifetime can be increased. Additionally, a non-transmissive barrier layer can be provided in the absorption region 704 to achieve enhanced inhibition of ingress on at least a portion of the barrier.

[0279] Further reduction in ingress may be required. The parallax barrier 700 is disposed between the pixel layer 214 and at least one light-transmissive inorganic layer 752, which is arranged to provide a barrier to water and oxygen. The inorganic layer 752 is separated by an organic layer 750. Advantageously, a high resistance to water and oxygen ingress can be provided in the flexible substrate.

[0280] Figure 7 FIG. 4 is a schematic diagram illustrating the spatial light modulator 48 and the structure of the alignment parallax barrier including the glass material 110 in a side view. Compared with Figure 6 the arrangement of, the glass material 110 can be provided for the cover layer 217, which provides a high barrier layer to oxygen and water ingress compared to the layers 752, 750 of Figure 6 . The separation layer 216 can be provided by an adhesive material or a polymer material. Alternatively, the separation layer 216 can be provided by a glass material, which is thinned by chemical mechanical polishing after manufacturing the backplane 212 and the pixel layer 214 to achieve the desired thickness d.

[0281] It can be assumed that the features of the arrangement of Figure 7 not further discussed in detail correspond to the features with equivalent reference numerals as discussed above, including any potential variations in the features.

[0282] The arrangement of the transmittance curve of the parallax barrier 700 will now be described in more detail.

[0283] Fig. 8A -FIG. 5C is a schematic diagram illustrating the variation of the transmittance of the parallax barrier 700 with the position of various parallax barrier 700 structures.

[0284] Fig. 8A Illustrates a first transmittance curve 701 of the relative transmittance with respect to the position in the direction θ closest to the hole; wherein the absorption region 704 has 100% absorption. Advantageously, at a polar angle greater than 45 degrees, extremely low brightness can be achieved in the privacy mode.

[0285] Figure 8B Illustrates the transmittance 705 of the absorption region 704 increased, for example, by controlling the thickness of the material used to form the absorption region 704. The absorption rate of the region of the parallax barrier 700 between the holes 702 is less than 100% and greater than 80%, preferably greater than 90% and more preferably greater than 95%. The transmittance 705 can be, for example, less than 5% or less than 2.5%. Advantageously, in the common operation mode, increased brightness can be provided at a higher polar viewing angle.

[0286] Figure 8C Illustrates, for example, by Figure 2AThe transmittance of the absorption region 704 increased due to the sub-aperture region 722 described in []. The average transmittance 705 across the light absorption region 704 can be, for example, less than 5% or less than 2.5%. Advantageously, in the common operating mode, increased brightness can be provided at higher polar viewing angles.

[0287] The structure of an exemplary embodiment of a polarizer will now be described. Figure 1A of the polarizer.

[0288] It can be assumed that the features of the arrangement of [] not further discussed in detail Fig. 8A -B correspond to the features with equivalent reference numerals as discussed above, including any potential variations in the features.

[0289] In the Figure 1A -B embodiment, the polarizer 300 includes a passive polarizer 330 and a switchable liquid crystal polarizer 301, but can generally be replaced by other configurations of at least one polarizer, some examples of which are present in the devices described below.

[0290] Fig. 9 FIG. [] is a perspective side view illustrating the arrangement of a switchable polarizer 300 including a liquid crystal polarizer 301, the liquid crystal polarizer including a switchable liquid crystal layer 314 with horizontal alignment and crossed A-plate polarizers 330A, 330B. It can be assumed that the features of the arrangement of [] not further discussed in detail Fig. 9 correspond to the features with equivalent reference numerals as discussed above, including any potential variations in the features.

[0291] Exemplary embodiments and polar curves in privacy and common modes are provided in Table 3.

[0292]

[0293] Table 3

[0294] The switchable liquid crystal polarizer 301 includes two surface alignment layers 419a, 419b, the two surface alignment layers being adjacent to the liquid crystal material 421 layer and disposed on opposite sides thereof, and each being arranged to provide horizontal alignment in the adjacent liquid crystal material 421. The layer 314 of the liquid crystal material 421 of the switchable liquid crystal polarizer 301 includes a liquid crystal material 421 having a positive dielectric anisotropy.

[0295] The passive polarization control retarder 330 is provided by a pair of A plates 330A, 330B having crossed axes. In the present embodiment, "crossed" means an angle of substantially 90° between the optical axes of the two retarders in the plane of the retarder. In order to reduce the cost of the retarder material, it is desirable to provide a material in which the retarder orientation varies somewhat, for example, due to stretching errors during thin film fabrication. Variations in the retarder orientation away from the preferred direction can reduce the front brightness and increase the minimum transmittance. Preferably, the angle 310A is at least 35° and at most 55°, more preferably at least 40° and at most 50°, and most preferably at least 42.5° and at most 47.5°. Preferably, the angle 310B is at least 125° and at most 145°, more preferably at least 130° and at most 135°, and most preferably at least 132.5° and at most 137.5°.

[0296] Horizontal alignment advantageously provides reduced recovery time during mechanical deformation (e.g., when touching a display). Stretch films can be used to provide the passive retarders 330A, 330B to advantageously achieve low cost and high uniformity. Additionally, the viewing field of the liquid crystal retarder with horizontal alignment is increased while providing resilience for the visibility of the flow of the liquid crystal material during the application of pressure.

[0297] At least one polarization control retarder 300 is arranged to perform the following operations simultaneously in the first switchable state of the switchable liquid crystal retarder 301: not introducing a net relative phase shift to the orthogonal polarization components of the light transmitted by the reflective polarizer 302 along the axis 199 normal to the plane of at least one polarization control retarder 300, and introducing a net relative phase shift to the orthogonal polarization components of the light transmitted by the reflective polarizer 302 along the axis 197 inclined to the normal of the plane of at least one polarization control retarder 300; and performing the following operations simultaneously in the second switchable state of the switchable liquid crystal retarder 301: not introducing a net relative phase shift to the orthogonal polarization components of the light transmitted by the reflective polarizer 302 along the axis 199 normal to the plane of at least one polarization control retarder 300, and not introducing a net relative phase shift to the orthogonal polarization components of the light transmitted by the reflective polarizer 302 along the axis 197 inclined to the normal of the plane of at least one polarization control retarder 300.

[0298] Such phase shifts provide polarization transmittance and reflectance curves that achieve the following: (i) high on-axis transmittance and low reflectance; (ii) in the privacy mode, reduced off-axis transmittance and increased reflectance; (ii) and in the common mode, high off-axis transmittance and low reflectance. Advantageously, as will now be described, the switchable privacy display provides high image quality to the front user, a high level of visual security to off-axis snoops, and high image visibility to off-axis display users.

[0299] Fig. 10A A schematic diagram showing the propagation of the output light from the spatial light modulator 48 through the optical stack in a common operating mode as viewed from a side view. Figure 1A of the optical stack.

[0300] In the common operating mode, the light ray 710 emitted by the pixels 220, 222, 224 in the on-axis direction and transmitted through the aperture 702 of the barrier 700 has a polarization state 360 parallel to the electric vector transmission direction 219 of the output polarizer 218. The on-axis light ray 710 then passes through a plurality of retarder layers 300 including a switchable liquid crystal retarder 301 and a passive retarder 330. In the common mode, the switchable liquid crystal retarder 301 is in the off state, where the control voltage across the liquid crystal layer 314 is different.

[0301] Therefore, the polarization state of the on-axis light ray 710 experiences a delay when passing through the switchable liquid crystal retarder 301. In the case where the passive retarder 330 is a C-plate retarder, the on-axis light ray 710 propagates in a direction substantially parallel to the optical axis of the passive retarder 330. Therefore, the on-axis light ray 710 experiences a minimum delay when passing through the passive retarder 330. The combined effect of the plurality of retarders 300 causes the on-axis light ray 710 to leave the plurality of retarders 300 with a linear polarization state 362 that is the same or similar to the linear polarization 360 of the on-axis light ray 710 entering the plurality of retarders 300. This linear polarization state 362 is parallel to the electric vector transmission direction 319 of the additional polarizer 318, so the on-axis light ray 710 leaves the display device 100 with relatively constant brightness.

[0302] In the common mode, the off-axis light ray 726 transmitted through the aperture 702 of the barrier 700 passes through the plurality of retarders 300 in a manner similar to the on-axis light ray 710. Therefore, when the switchable liquid crystal retarder 301 is in the first of the two states, the plurality of retarders 300 do not provide an overall transformation of the polarization states 360, 361 of the following light rays: the light ray 710 passing through it perpendicular to the plane of the switchable retarder or the light ray 726 passing through it at an acute angle to the plane perpendicular to the switchable retarder 301.

[0303] The polarization state 362 is substantially the same as the polarization state 360, and the polarization state 364 is substantially the same as the polarization state 361. Therefore, the angular transmission curve is substantially uniformly transmitted over a wide polar region.

[0304] In other words, when the layer 314 of the liquid crystal material 414 is in the first of the two states, the plurality of retarders 300 do not provide an overall delay to the light passing through it perpendicular to the plane of the retarder or at an acute angle to the plane perpendicular to the plurality of retarders 300.

[0305] Advantageously, in the first state, the change in the display brightness with the viewing angle is substantially unchanged. Multiple users can conveniently view the display from a wide range of viewing angles.

[0306] Fig. 10B FIG. is a side view illustrating the propagation of light from the ambient light source 604 through the Figure 1A optical stack in the common operating mode.

[0307] The on-axis light ray 410 of the ambient light 604 passes through the plurality of retarders 300 in a manner similar to the on-axis light rays 710 emitted from the emission pixels 220, 222, 224 discussed above. Although the direction in which the on-axis light ray 410 passes through the plurality of retarders 300 is opposite to the direction in which the on-axis light rays 710 are emitted from the emission pixels 220, 222, 224, passing through the plurality of retarders 300 in the opposite direction does not change the effect of the plurality of retarders 300 on the light, as discussed above for the light emitted from the emission pixels 220, 222, 224. Thus, the on-axis light ray 410 reaches the absorption region 704 of the parallax barrier 700 where it is absorbed; or the pixel layer 214 where it can be absorbed or reflected, as will be further described below.

[0308] In a similar manner, the off-axis light ray 412 does not undergo an overall transformation of the polarization state when passing through the plurality of retarders 300. The ambient light 604 is unpolarized, and the off-axis light ray is initially not polarized 370. The additional polarizer 318 allows the polarization component 372 parallel to the electric vector transmission direction 319 of the additional polarizer to pass through. The additional polarizer 318 absorbs most of the polarization state 372 perpendicular to the electric vector transmission direction 319 of the additional polarizer 318. Some light is reflected from the front surface of the polarizer 318 by Fresnel reflection at the external air interface. After passing through the plurality of retarders 300, the linear polarization state 374 of the off-axis light ray 412 is thus parallel to the electric vector transmission direction 303 of the reflective polarizer 302, and the off-axis light ray is not reflected but passes through the reflective polarizer 302 to reach the parallax barrier 700, where it can be absorbed by the absorption region of the parallax barrier or transmitted to the pixel layer 214. As further described below, some of the reflected light rays 412 will be further absorbed by the absorption region 704 of the parallax barrier 700.

[0309] Advantageously, the display reflectivity in the common mode decreases over a wide viewing angle range. Multiple users can conveniently view the display with high image contrast from a wide range of viewing angles.

[0310] Fig. 10C FIG. is a side view illustrating the propagation of the output light from the spatial light modulator 48 through the Figure 1A optical stack in the privacy operating mode.

[0311] In the privacy mode, the switchable liquid crystal retarder 301 is in the on state, where a voltage is applied to the liquid crystal layer 314. The switchable liquid crystal retarder 301 can thus be in the second of the two states. In the case where the switchable liquid crystal retarder 301 has positive dielectric anisotropy, the switchable liquid crystal retarder 301 thus acts in a similar manner in the second state to adjust the phase of the incident polarization state of the output. When passing through the switchable liquid crystal retarder 301 in the second state, the on-axis light ray 710 does not experience retardation, and thus the linear polarization state 360 of the on-axis light ray 710 before passing through the plurality of retarders 300 is the same as the linear polarization state 362 after passing through the plurality of retarders 300. Accordingly, the on-axis light ray 710 exits the display through the additional polarizer 318 with substantially unchanged brightness in the privacy operation mode.

[0312] The off-axis light ray 726 emitted from the emission pixels 220, 222, 224 and transmitted through the holes 702 of the barrier 700 undergoes a polarization transformation when passing through the material of the switchable liquid crystal retarder 301. This is because the off-axis light ray 726 is incident at an acute angle. Accordingly, the off-axis light ray 726 arrives at the additional polarizer 318 with a linear polarization state 364 that is at least partially rotated compared to the linear polarization state 361. The linear polarization 364 has at least some components perpendicular to the electric vector transmission direction 319 of the additional polarizer 318, and thus the brightness of the off-axis light ray 726 is reduced compared to the on-axis light ray 710.

[0313] Advantageously, the display brightness at wide viewing angles can be reduced in the second state. Thus, a snoop can be prevented from observing the image emitted by the display device 100 at wide viewing angles. Stray light can be reduced during night operation, while a front user can see the image.

[0314] Fig. 10D FIG. is a side view illustrating the propagation of light rays from an ambient light source 604 through Figure 1A the optical stack in the privacy operation mode.

[0315] In the privacy mode of operation, the incident on-axis light ray 410 from the ambient light source 604 is similar to that regarding Fig. 10CThe described manner of emitting on-axis light rays 710 from emission pixels 220, 222, 224 passes through a plurality of retarders 300. Although the direction in which the on-axis light ray 410 passes through the plurality of retarders 300 is opposite to the direction in which the on-axis light ray 710 is emitted from the emission pixels 220, 222, 224, the direction of the plurality of retarders 300 in and out of the display does not change the effect of the plurality of retarders 300 on the light rays, as discussed for the light emitted from the emission pixels 220, 222, 224. Thus, the on-axis light ray 410 reaches the parallax barrier 700, where the on-axis light ray may be absorbed by the absorption region of the parallax barrier or transmitted to the pixel layer 214. As further described below, some of the reflected light rays 412 will be further absorbed by the absorption region 704 of the parallax barrier 700.

[0316] In contrast, the off-axis light ray 412 undergoes a polarization transformation when passing through the material 414 of the switchable liquid crystal retarder 301. This is because the off-axis light ray 412 is incident at an acute angle, as discussed in further detail below. Thus, the off-axis light ray 412 reaches the reflective polarizer 302 with a linearly polarized state 374 that is at least partially rotated compared to the linearly polarized state 372. The linearly polarized state 374 has at least some states perpendicular to the electric vector transmission direction 303 of the reflective polarizer 302, and thus is at least partially reflected by the reflective polarizer 302. Then, the light ray 412 passes through the plurality of retarders 300 in the opposite direction, thereby reversing the polarization conversion from the first pass through the plurality of retarders 300 and generating a polarized state 376 parallel to the electric vector transmission direction of the additional polarizer 318. Thus, the off-axis light ray 412 leaves the display device 100 in a polarized state 378, resulting in the stack appearing as a mirror when viewed from a wide angle. The additional polarizer 318 absorbs most of the polarized state 372 perpendicular to the electric vector transmission direction 319 of the additional polarizer, but may reflect a small portion of the perpendicular state 404.

[0317] Advantageously, in the second state, the reflectivity at a wide viewing angle can be increased. Thus, a snoop can be prevented from viewing the image emitted by the display device 100 at a wide viewing angle, since the reflected light reduces the contrast of the image emitted by the display device, and thus increases the visual security level VSL due to the increased reflectivity R, as described in Equation 7 above.

[0318] It can be assumed that the features of the Fig. 10A -D arrangement correspond to the features with equivalent reference numerals as discussed above, including any potential variations in the features.

[0319] The simulated output of the illustrative embodiment will now be described.

[0320] Fig.11A is Figure 1AComponent weightings of the arrangement and the output polar plot arrays, including spatial light modulator 48 luminance, parallax barrier 700 transmittance, switchable retarder 300 transmittance, normalized switchable retarder 300 reflectance, common mode luminance, privacy mode luminance, and polar plots for a visual safety level of 1.0 lux / nit ratio; and Fig. 11B is Fig.11A Component weightings of the arrangement and the output line graph arrays, including line graphs for azimuth angles of 0 degrees (east direction), 90 degrees (north direction), 45 degrees (northeast direction), and 225 degrees (southwest direction). For the purposes of the current description, on Fig.11A the SLM luminance map of Fig. 11B the azimuthal orientation of the curves in

[0321] Fig.11A - Illustrative parallax barrier 700 and OLED pixel parameters for -B are provided in the first row of Table 4 with a spacing p of 50 μm in the direction of the closest pixels. In Figure 4 the diamond arrangement of

[0322]

[0323] Table 4

[0324] After considering the transmission of polarized light by polarizer 318 and the reflection of polarized light by reflector 302, a peak eQM reflectance of 36% is used, which corresponds to the 100% contour on the graph of the normalized switchable retarder reflection.

[0325] The SLM 48 luminance map shows that the OLED display provides non-Lambertian luminance attenuation, which typically has a front luminance greater than 20% of that provided at a polar angle of 50 degrees.

[0326] The parallax barrier 700 transmittance map shows the differences in the curves for azimuth angles of 0 degrees and 45 degrees due to the different separations of the pixels in this orientation.

[0327] The switchable retarder 300 transmittance and reflectance maps show the use of Fig. 9 the structure to control the phase along the transverse direction.

[0328] The common mode illuminance is determined by the transmittance of the parallax barrier 700 for the light from the spatial light modulator 48. The switchable polarity control retarder 300 only provides a small modulation of this luminance curve.

[0329] Privacy Mode Brightness Description Provides less than 1% brightness in the lateral direction and in the upper viewing quadrant. The display has high visibility for 0 degree side angles and for rotation about the horizontal axis. Advantageously, a comfortable viewing angle can be set for a user to view the display from an on-axis position.

[0330] The effect of ambient light level on visual safety level will now be described.

[0331] Fig. 11C The lux / nit ratio is 0.25 Fig.11A The display 100 characteristics are described in the second row of Table 4.

[0332] The Visual Safety Level (VSL) graph depends on the ambient illumination conditions. Ambient illumination is provided as a ratio of the frontal luminance. Thus, in a typical office environment, a display with a frontal luminance of 300 nits and an ambient luminance of 300 lux falling on the display has a lux / nit ratio of 1.0. In a darkened aircraft cockpit, a frontal luminance of 100 nits may be provided for an ambient luminance of 25 nits, providing a lux / nit ratio of 0.25.

[0333] The switchable reflectivity of embodiments of the present invention achieves increased visual safety levels at low lux / nit ratios. In addition, parallax barrier 700 can further reduce off-axis brightness to advantageously achieve further increased visual safety under low illumination conditions.

[0334] It has been determined by means of experiments and simulations that a visual safety level greater than 3.0 and preferably greater than 4.0 in privacy mode is required for a high degree of isolation of the displayed image from off-axis snoopers. It has also been determined by means of experiments and simulations that an image visibility W greater than 50% and preferably greater than 83.3% (a visual safety level V less than 2.0 and preferably less than 1.2 in public mode) achieves the desired image visibility of the displayed image for off-axis users.

[0335] Fig. 11B The visual safety level curve for -C illustrates that a visual safety level of greater than 4.0 can be achieved for side angles and in the viewing quadrant at side angles of at least 45 degrees, and for azimuth angles in the viewing quadrant in the lateral direction and under lighting conditions of less than 0.25 lux / nit. Advantageously, high visual safety levels can be achieved for off-axis users at various polar positions. The visual safety level does not degrade at higher polar angles in the lateral direction.

[0336] By comparison with the embodiment of the present invention, the embodiment in which the parallax barrier 700 is omitted will now be described. Figure 1A A simulated appearance of the arrangement.

[0337] Fig. 12A for an illustrative arrangement in which the parallax barrier 700 is removed Figure 1A a polar plot array of the component weights and outputs of the arrangement, including spatial light modulator 48 luminance, parallax barrier 700 transmittance, switchable retarder transmittance, switchable retarder reflectance, common mode luminance, privacy mode luminance, and a polar plot of the visual safety level at 1.0 lux / nit; and Fig. 12B is Fig. 12A a linear graph array of the component weights and outputs of the arrangement, including linear graphs at azimuth angles of 0, 90, 45, and 225 degrees. The display 100 characteristics are described in the third row of Table 4.

[0338] By comparison with an embodiment of the present invention as will be described in Fig. 12A -B, the polarizing control retarder 300 may not achieve the desired visual safety level in a display having a high off-axis luminance level, such as is typically provided by an emissive spatial light modulator 48 in which there is no parallax barrier 700.

[0339] Considering the linear polarization graph of the visual safety level in the lateral (0 degree) direction at angles greater than 60 degrees, for 1.0 lux / nit, the VSL is below 4.0. This arrangement provides an undesirable visual safety to off-axis snoops, despite having a high VSL at an angle of approximately 45 degrees.

[0340] By comparison with an embodiment of the present invention, the simulated appearance of an arrangement Figure 1A in which the polarizing control retarder 300 is omitted will now be described.

[0341] Fig.13A for an illustrative arrangement in which the switchable retarder is removed Figure 1A a polar plot array of the component weights and outputs of the arrangement, including spatial light modulator 48 luminance, parallax barrier 700 transmittance, switchable retarder transmittance, switchable retarder reflectance, common mode luminance, privacy mode luminance, and a polar plot of the visual safety level for 1.0 lux / nit; and Fig. 13B is Fig.13A a linear graph array of the component weights and outputs of the arrangement, including linear graphs at azimuth angles of 0, 90, 45, and 225 degrees.

[0342] The display 100 characteristics are described in the fourth row of Table 4. The parallax barrier thickness 700 is designed to be a minimum thickness to provide a VSL greater than 4.0 at at least one azimuth angle at a 45 degree polar angle in the lateral direction.

[0343] This display has an undesirable privacy performance within a wide range of polar viewing angles, especially in the viewing quadrants, without significantly reducing the aperture size and subsequent undesirable loss of transmission efficiency.

[0344] We will now further consider the spectral transmission and spectral reflection of ambient light from the surface of the display 100 in a common operating mode Figure 1A thereof.

[0345] Fig.14 Figure 9 is a side view illustrating a schematic diagram of the reflection of ambient light in the display 100 Figure 1A thereof. It can be assumed that the features of the arrangement Fig.14 not further discussed in detail correspond to the features with equivalent reference numerals as discussed above, including any potential variations in the features.

[0346] The light rays 710 are transmitted by the linear polarizers 218, 318, where the spectral transmission of the polarizers 218, 318 provides spectral modification of the light from the pixels 220, 222, 224.

[0347] The light rays 714, 715 are totally internally reflected from the outer surface of the display 100. The light ray 714 that would be absorbed upon incidence is directed onto the absorption region 704 of the parallax barrier 700. The light ray 715 is reflected from the reflective pixel layer 214. The reflection-reducing quarter-wave retarder 228 provides a circularly polarized state 442 that undergoes a phase change upon reflection to provide a circularly polarized state 444 after reflection, which is converted to a polarized state orthogonal to the direction 219 and absorbed.

[0348] Therefore, the light rays 714, 715 pass through the polarizers 218, 318 two or three times, thus modifying the spectral absorption rate.

[0349] The parallax barrier 700 is arranged to absorb the light incident thereon. The light rays 410 from the ambient source 604 are transmitted by the polarizers 218, 318 and absorbed by the barrier region 704. The light rays 412 that pass through the barrier and are reflected can be absorbed by the barrier after reflection. The display 100 device can be used for ambient lighting 604, and the parallax barrier 700 absorbs at least some of the ambient lighting 604 light rays 412 that are reflected from the pixel layer 214 and transmitted through the apertures 702.

[0350] It is necessary to increase Figure 1A the spectral transmittance of the display 100. Additionally, it is necessary to increase the blue transmittance without degrading the appearance of the display reflection.

[0351] Fig.15It is a schematic diagram showing the variation of the output brightness with the wavelength in the case where the additional polarizer 318 is a broadband absorption polarizer and in the case where the additional polarizer 318 is a leakage absorption polarizer. Curve 870 shows the variation of the brightness transmitted by the parallel broadband polarizer; curve 872 shows the variation of the brightness transmitted by the parallel leakage polarizer; curve 874 shows the variation of the brightness transmitted by the crossed broadband polarizers; and curve 876 shows the variation of the brightness transmitted by the crossed leakage polarizers. The leakage polarizer 318 increases the leakage in the blue spectral band and increases the transmittance.

[0352] When crossed with a second conceptual polarizer of the same material, the transmittance of the output polarizer 218 and the additional polarizer 318 for wavelengths from 520 nm to 560 nm is less than the transmittance for wavelengths from 450 nm to 490 nm. The transmittance for wavelengths from 450 nm to 490 nm is greater than 1%, preferably greater than 2% and most preferably greater than 3%; and the transmittance for wavelengths from 520 nm to 560 nm is less than 3%, preferably less than 2% and most preferably less than 1%.

[0353] The operation of the display 100 when using a leakage polarizer will now be described. Figure 1A when using a leakage polarizer.

[0354] Fig.16A It is a schematic diagram showing the variation of the transmittance of the polarizers 218, 318 with the wavelength of the broadband absorption polarizer and the leakage absorption polarizer and with respect to Fig.14 the spectral outputs 890R, 890G, 890B of the red, green, and blue emission pixels 220, 222, 224 of the transmitted light ray 710.

[0355] Curve 882 shows the spectral transmittance of an Figure 1A embodiment including the leakage polarizers 218, 318.

[0356] By comparison with an embodiment of the present invention, curve 880 shows the spectral transmittance of an Figure 1A embodiment including the broadband absorption polarizers 218, 318. Advantageously, compared with the arrangement including the broadband polarizers 218, 318, the embodiment of the present invention illustrated by curve 882 has a substantially higher transmittance in the red, green, and blue channels.

[0357] Further comparison with embodiments of the present invention shows that curve 870 illustrates the spectral output of a display that includes a broadband absorption polarizer and a broadband reflectivity control quarter-wave retarder, and does not include barrier 700, polar control retarder 300, or additional polarizer 318. Advantageously, embodiments of the present invention illustrated by curve 882 have substantially the same blue light transmittance as a display that does not include additional polarizer 318. Efficient blue light emission provides a longer service life for OLED displays. Advantageously, embodiments of the present invention achieve the same display life as a conventional display without an additional polarizer 318.

[0358] Fig. 16B is a schematic diagram illustrating the variation of reflectivity with the wavelength of broadband absorption polarizers 218, 318 and leakage absorption polarizers 218, 318 and the spectral outputs 890R, 890G, 890B of red, green, and blue emission pixels 220, 222, 224 of transmitted light relative to Fig.14

[0359] The reflectivity is at least partially determined by Fig.14 the transmittance of light 440 in [] through polarizers 218, 318 after reflection reduction quarter-wave retarder 228 and the absorption rate of parallax barrier 700.

[0360] Continuing with the illustrative embodiment of the first row of Table 4, the aperture ratio of the parallax barrier is 25%, such that Fig.14 the barrier absorption rate of light 410, 412 is 75%. Returning to the embodiment of [] that includes leakage polarizers 218, 318, curve 888 illustrates the average spectral transmittance of the display integrated in terms of viewing angle. Advantageously, a very low average reflectivity can be provided by the display. As Fig.14 illustrated in [], the display efficiency is further increased. Fig.16A

[0361] Curve 884 illustrates Fig.14 the spectral transmittance of a display for light 440 transmitted and reflected by holes 702 of parallax barrier 700. Compared with curve 876, curve 884 shows a significant improvement in extinction when the leakage at the peak blue spectral wavelength is less than 1%. Advantageously, a low reflectivity is achieved.

[0362] Further comparison with embodiments of the present invention shows that curve 886 illustrates the spectral output of a display that includes a broadband absorption polarizer and a broadband reflectivity control quarter-wave retarder, and does not include barrier 700, polar control retarder 300, or additional polarizer 318. This display achieves a low reflectivity in a wide spectral range but reduces the spectral transmittance.

[0363] Further comparison with embodiments of the present invention shows that curve 876 illustrates the spectral output of a display that includes a leaky absorption polarizer and a broadband reflectance control quarter-wave retarder and does not include barrier 700, polarizer control retarder 300, or additional polarizer 318. This display achieves low reflectance over a wide spectral range. This display exhibits an undesired reflectance of light, particularly in the blue and green portions of the spectrum. Thus, the leaky polarizers with spectral transmittance curves 872, 876 are not suitable for reflectance control in emissive displays.

[0364] The operation of an embodiment including inorganic micro-LEDs will now be described.

[0365] Fig.17A FIG. 7 is a schematic side perspective view of a switchable privacy display 100 for ambient lighting 604, including a micro-LED emissive spatial light modulator 48, a parallax barrier 700, an output polarizer 218, and a reflection control quarter-wave retarder 228, a passive polarizer control retarder 380, a reflective polarizer 302, a switchable polarizer control retarder 300, and an additional polarizer 318 disposed on the output side of the spatial light modulator 48; and Fig. 17B FIG. 9 is a front view illustrating Fig.17A the alignment of the optical layers in the optical stack of FIG. 8. It can be assumed that the features of the arrangement of FIG. 8 - B that are not further discussed in detail Fig.18A correspond to the features with equivalent reference numerals as discussed above, including any potential variations in the features.

[0366] Compared to OLED materials, the pixels 220, 222, 224 including inorganic micro-LEDs can have a luminance greater than 10 3 lm / mm 2 2). To achieve the same brightness, the area of the micro-LED pixels 220, 222, 224 can be significantly smaller than the area used for the OLED pixels 220, 222, 224. Due to the reduced use of monolithic semiconductor area, the other smaller micro-LED pixels 220, 222, 224 are less costly. For example, for a pixel pitch of 50 microns in the direction of closest pixels, the micro-LEDs can have a width or diameter of less than 5 microns.

[0367] There is a need to implement a common operating mode with high image visibility over a wide polarization range and a privacy mode with a high level of visual security for off-axis snoops.

[0368] The pixel layer 214 can include a light-absorbing material 227 to advantageously achieve a reduced reflectance compared to the typical reflective pixel layer of the OLED pixel layer 214 of FIG. 8 - B. Figure 1A

[0369] Fig.17A also differs from Figure 1A in that it includes holes 702 having a circular shape. Advantageously, the symmetry of the transmittance curve can be increased.

[0370] Pixels 220, 222, 224 are arranged on a square grid instead of a rhombic grid. This arrangement reduces the brightness in the lateral direction while increasing the brightness in the quadrants. Advantageously, the visual security level in the privacy mode can be increased for small elevation angles, as described below.

[0371] In an embodiment (not shown), a display (not shown) including a mixture of OLEDs and micro-LED pixels can be provided. For example, blue micro-LEDs and green and blue OLED pixels can be provided. Advantageously, the blue lifetime can be increased without using color conversion for the micro-LEDs.

[0372] Fig. 17C is a schematic diagram showing the arrangement of the micro-LED emitting pixels 220, 222, 224 and the eye point positions for various polar viewing angles in a top view.

[0373] Fig.17D is a schematic diagram showing the passive polarization control retarder 380 arranged between the output polarizer 218 and the reflective polarizer 302 in a side perspective view.

[0374] The passive polarization control retarder 380 is arranged between the output polarizer 218 and the reflective polarizer 302. The passive polarization control retarder 380 is capable of simultaneously performing the following operations: not introducing a net relative phase shift to the orthogonal polarization component of the light transmitted by the output polarizer 218 along the axis 199 normal to the plane of at least one polarization control retarder 380, and introducing a relative phase shift to the orthogonal polarization component of the light transmitted by the reflective polarizer 302 along the axis 197 inclined to the normal of the plane of at least one polarization control retarder 380.

[0375] At least one passive retarder 380 includes a retarder material 430 having an optical axis 431 perpendicular to the plane of the retarder. The at least one passive retarder 330 has a retardation for light with a wavelength of 550 nm in the range of -150 nm to -900 nm, preferably in the range of -200 nm to -500 nm, and most preferably in the range of -250 nm to -400 nm.

[0376] The operation of the passive polarization control retarder 380 will be further described below with respect to Fig.19A -B.

[0377] It is necessary to optimize the spatial brightness uniformity of the display 100 including the micro-LED pixels 220, 222, 224.

[0378] Fig.18A FIG. is a schematic view showing a spatial light modulator and the structure of an alignment parallax barrier including a vignetting parallax barrier hole in a side view.

[0379] The hole 702 has an absorption rate, and at the edge of the hole 702, the absorption rate has a transmittance gradient, and the transmittance gradient has a transmittance gradient width ε greater than 1 μm, preferably greater than 2 μm, and more preferably greater than 3 μm.

[0380] In operation, the point emitter 720 within the pixel 222 emits a spherical wavefront 711 towards the hole 702. When the wavefront 711 is incident on the hole 702, the residual wavefront curvature causes near-field Fresnel diffraction, such that light rays 714 are provided at an unexpected angle in the far field.

[0381] In a parallax barrier having a hard edge such that the transmittance gradient width ε is less than 1 μm, such light rays can provide an undesired polar brightness variation from a point source and provide a visible uniformity variation that an observer can see over an area of the display 100.

[0382] In an illustrative micro-LED embodiment, the pixel pitch p can be 50 μm and the pixel width can be 3 μm. In an illustrative OLED embodiment, the pixel pitch p can be 50 μm and the pixel width can be 25 μm. In both arrangements, the hole 702 width a can be 16 μm. In a display having organic emitters such as those shown in Figure 1A the diffraction light rays are blurred due to convolution with a large pixel area. Advantageously, high display uniformity can be achieved. Due to the small size of the micro-LED emitters 220, 222, 224, the convolution blur in the OLED arrangement may be substantially greater than that in the micro-LED display.

[0383] In an embodiment of the present invention, the transmittance gradient width ε provides a diffraction apodization of the diffraction light rays 714, especially for small emission regions, such as micro-LEDs that do not provide a large amount of convolution blur. The brightness variation of the diffraction light rays 714 decreases due to the decrease in the transmittance gradient width ε. Advantageously, the visibility of the spatial brightness variation on a display using micro-LED pixels 220, 222, 224 is reduced.

[0384] The transmittance curves of various parallax barriers 700 will now be further described.

[0385] Fig.18B -D is a schematic view showing the variation of the parallax barrier transmittance with the position of the structure of various parallax barriers 700.

[0386] Fig.18BDescribe a first apodized transmittance curve 701 of relative transmittance with respect to a position in the direction θ closest to the aperture; wherein the absorption region 704 has 100% absorptance. The slope can be formed by a change in the thickness of the absorbing material and / or a halftone pattern across the width ε. Advantageously, the brightness variation across the display can be minimized. Within the width ε of the slope of curve 701, as referenced Fig.18A as described, the transmittance varies to apodize the output.

[0387] Fig. 18C Describe the transmittance 705 of the absorption region 704 increased, for example, by controlling the thickness of the material used to form the absorption region 704. The absorptance of the parallax barrier 700 region between the apertures 702 is less than 100% and greater than 80%, preferably greater than 90% and more preferably greater than 95%. The transmittance 705 can be, for example, less than 5% or less than 2.5%. Advantageously, in a common operating mode, increased brightness can be provided at higher polar viewing angles.

[0388] Fig.18D Describe the transmittance of the absorption region 704 increased, for example, Figure 2A by the sub-aperture region 722 as illustrated in

[0389] Now will describe Fig.17A the simulated output of an illustrative embodiment of

[0390] Fig.19A is a polar plot array of component weights and outputs of an arrangement omitting the passive polarizing retarder 380, including spatial light modulator 48 brightness, parallax barrier 700 transmittance, switchable retarder 300 transmittance, normalized switchable retarder 300 reflectance, common mode brightness, privacy mode brightness, and a polar plot of the visual safety level for a lux / nit ratio of 1.0; and Fig.17A is a linear graph array of component weights and outputs of an arrangement of Fig.19B is Fig.19A of an arrangement.

[0391] Fig.19A -B illustrative parallax barrier 700 and micro-LED pixel 220, 222, 224 parameters in the direction closest to the pixel are provided in the first row of Table 5 for a pitch p of 50 μm. The pixels 220, 222, 224 are provided in a square packing arrangement and provide square parallax barrier 700 apertures 702 (compared to the illustrated circular apertures). The direction closest to the pixel is for an azimuth angle of 0 degrees. Fig. 17C as provided and provide square parallax barrier 700 apertures 702 (compared to the illustrated circular apertures). The direction closest to the pixel is for an azimuth angle of 0 degrees.

[0392]

[0393] Table 5

[0394] Compared with Fig.11A the output of, the luminance curves from the micro-LED pixels 220, 222, 224 are shown as Lambertian and thus provide a higher level of luminance at higher polar angles.

[0395] The polar output curve from the parallax barrier 700 has a high center output region and then slopes to 5% luminance at high polar angles using an arrangement such as Figure 2A . Advantageously, the common operating mode maintains the required image visibility at high viewing angles.

[0396] The slope of the luminance decay in the common mode is determined by the profile of the barrier edge which is a hard edge in this illustrative embodiment. Fig.18A A soft-edge parallax barrier of -D can further achieve a smoother decay of the luminance curve in the common operating mode. Advantageously, the luminance uniformity for front use and the uniformity of the off-axis polar viewing region are improved.

[0397] In the privacy operating mode, a visual safety level greater than 4.0 is advantageously achieved for polar angles greater than 45 degrees and especially in the viewing quadrant. In other embodiments not shown, the visual safety level can be further increased by reducing the transmission level of the absorption region 704 of the parallax barrier 700.

[0398] It may be necessary to provide further luminance reduction in the viewing quadrant.

[0399] Fig.19C is Fig.17A a polar plot array of the component weights and outputs of the arrangement, including the luminance of the spatial light modulator 48, the transmittance of the light absorption region 704 of the parallax barrier 700, the transmittance of the passive polar control retarder 380, the transmittance of the switchable retarder 300, the reflectance of the switchable retarder 300, the common mode luminance, the privacy mode luminance, and the visual safety level; and Fig.19D is Fig.19C a linear graph array of the component weights and outputs of the arrangement, including the linear curves at azimuth angles of 0, 90, 45, and 225 degrees. The characteristics of the display 100 are described in the second row of Table 5. The passive polar control retarder 380 reduces the luminance in the viewing quadrant. Advantageously, the visual safety level in the viewing quadrant can be improved.

[0400] By comparison with embodiments of the present invention, the simulated appearance of an arrangement omitting the parallax barrier 700 and the polar control retarder 380 will now be described. Fig.17A of the arrangement.

[0401] Fig. 20Afor an illustrative arrangement in which the parallax barrier 700 is removed Fig.17A a polar plot array of the component weights and outputs of the arrangement, including the spatial light modulator 48 luminance, the parallax barrier 700 light absorption region 704 transmittance, the switchable retarder 300 transmittance, the switchable retarder 300 reflectance, the common mode luminance, the privacy mode luminance, and the visual safety level polar plot; and Fig. 20B is Fig. 20A a linear graph array of the component weights and outputs of the arrangement, including the linear curves at azimuth angles of 0, 90, 45, and 225 degrees. The display 100 characteristics are described in the third row of Table 5.

[0402] By comparison with embodiments of the present invention, the polarizing control retarder 300 may not achieve the required visual safety level in a display having a high off-axis luminance level, such as is typically provided by a transmissive spatial light modulator 48 including micro LEDs in which no parallax barrier 700 is present.

[0403] Considering the linear polar graph of the visual safety level in the lateral (0 degree) direction at angles greater than 60 degrees, for almost all polar viewing angles, the VSL remains below 4.0 for 1.0 lux / nit. This arrangement provides undesirable visual security for off-axis snoops.

[0404] By comparison with embodiments of the present invention, the simulated appearance of an arrangement omitting the polarizing control retarders 300, 380 will now be described Figure 1A of the arrangement

[0405] Fig.21A for an illustrative arrangement in which the switchable retarder 300 and the passive polarization control retarder 380 are removed and the parallax barrier 700 provides transmission in the light absorption region 704 Fig.17A a polar plot array of the component weights and outputs of the arrangement; including the spatial light modulator 48 luminance, the parallax barrier 700 transmittance, the switchable retarder 300 transmittance, the switchable retarder 300 reflectance, the common mode luminance, the privacy mode luminance, and the visual safety level polar plot; and Fig. 21B is Fig.21A a linear graph array of the component weights and outputs of the arrangement, including the linear curves at azimuth angles of 0, 90, 45, and 225 degrees. The display 100 characteristics are described in the fourth row of Table 5. To achieve the required image visibility in the common mode, the luminance at high polar viewing angles is 5%. However, the visual safety level is below 4.0 for all polar viewing angles and below 2.0 for most polar viewing angles. This display does not provide a satisfactory privacy operation mode.

[0406] Fig. 21Cfor an illustrative arrangement in which the switchable retarder 300 and the passive polarization control retarder 380 are omitted and the parallax barrier 700 provides no transmission in the light absorption region 704 Fig.17A a polar plot array of the component weights and outputs of the arrangement; including polar plots of spatial light modulator 48 luminance, parallax barrier 700 transmittance, switchable retarder 300 transmittance, switchable retarder 300 reflectance, common mode luminance, privacy mode luminance, and visual security level; and Fig.21D is Fig. 21C a linear graph array of the component weights and outputs of the arrangement, including linear graphs at azimuth angles of 0, 90, 45, and 225 degrees. The characteristics of the display 100 are described in the fifth row of Table 5. To achieve the desired visual security level in the privacy mode, the luminance at high polar viewing angles is 0%, i.e., the absorption region 704 is highly absorptive. However, for polar viewing angles greater than about 45 degrees, no image visibility is provided. This display does not provide a satisfactory common operating mode. A transmission level between 0% and 5% does not provide a satisfactory compromise between the privacy and common operating modes.

[0407] Advantageously, embodiments of the present invention achieve a high visual security level over a wide polar range in the privacy mode and high image visibility over a wide polar range in the common mode. In addition, high front image visibility is achieved in both the privacy and common operating modes.

[0408] Other arrangements of the polarization control retarder will now be described.

[0409] Fig.22A is a schematic diagram illustrating the arrangement of the switchable retarder in the privacy mode in a perspective side view, where the switchable retarder includes a switchable LC layer having a horizontal alignment disposed between C-plate passive polarization control retarders 330A, 330B; and Fig. 22B is a schematic diagram illustrating the arrangement of the switchable retarder in the common mode in a perspective side view, where the switchable retarder includes a switchable LC layer having a horizontal alignment disposed between C-plate passive polarization control retarders 330A, 330B. It can be assumed that the features of the arrangement of -B correspond to the features with equivalent reference numerals as discussed above, including any potential variations in the features. Figure 22A -B

[0410] The retarders 330A, 330B can include substrates for the switchable liquid crystal layer 314. Advantageously, the thickness can be reduced. In addition, a flexible substrate can be provided. The display 100 can be provided in an active flexible embodiment (which can be bent multiple times by the user) or in a passive flexible embodiment (which can be bent during manufacturing) to achieve a free-form display profile.

[0411] Displays that operate in both landscape and portrait orientations for both privacy and public operation modes are required.

[0412] Figure 23A FIG. 4 is a schematic diagram showing the arrangement of a retarder layer disposed between parallel polarizers and including a 270-degree supertwist switchable liquid crystal retarder 301 disposed between quarter-wave plates. It can be assumed that the Figure 23A features of the arrangement of -C correspond to the features with equivalent reference numerals as discussed above, including any potential variations in the features. Other embodiments of a polarity control retarder that achieve a symmetric polarity distribution are described in U.S. Patent Publication No. 2020-0159055, which is incorporated herein by reference in its entirety.

[0413] A first quarter-wave plate 296A and a second quarter-wave plate 296B are disposed between an additional polarizer 318 and an output polarizer 218. The first quarter-wave plate 296A is disposed on the input side of the second quarter-wave plate 296B and is arranged to convert the polarization state of linearly polarized light transmitted by the output polarizer 218 on its input side into a circularly polarized state. The second quarter-wave plate 296B on the output side is arranged to convert the polarization state of circularly polarized light incident thereon into a linearly polarized state transmitted by the additional polarizer 318 on its output side. At least one retarder 301 is disposed between the pair of quarter-wave plates 296A, 296B.

[0414] At least one polarity control retarder 300 includes a switchable liquid crystal retarder 301, which includes a liquid crystal material layer and electrodes arranged to apply a voltage to switch the liquid crystal material layer. The liquid crystal material layer has a twist of 360 degrees and has a retardation for light with a wavelength of 550 nm in the range of 1100 nm to 1400 nm, and most preferably in the range of 1150 nm to 1300 nm.

[0415] The simulation output of an illustrative embodiment of a Figure 23A switchable polarity control retarder including Figure 17A will now be described.

[0416] Figure 23B is a polar plot array of the component weights and outputs of an arrangement that omits the passive polarity control retarder 380, including the spatial light modulator 48 brightness, the parallax barrier 700 transmittance, the switchable retarder 300 transmittance, the normalized switchable retarder 300 reflectance, the common mode brightness, the privacy mode brightness, and the polar plot of the visual safety level for a lux / nt ratio of 1.0; and Figure 17A is Figure 23C isFigure 23A Component weight ratios of the arrangement and an array of linear graphs of the output.

[0417] Descriptive liquid crystal retarder 300 is described in Table 6. Figure 23B -C Descriptive parallax barrier 700 and OLED pixels 220, 222, 224 with a pitch p of 50 μm in the direction of the closest pixels are described in Table 7. Pixels 220, 222, 224 are provided in a Figure 4 square packing arrangement and provide square parallax barrier 700 holes 702. The direction of the closest pixels is for an azimuth angle of 0 degrees.

[0418]

[0419] Table 6

[0420]

[0421] Table 7

[0422] Advantageously, a rotationally symmetric privacy mode can be achieved as compared to the laterally symmetric curves achieved by embodiments using a polarizing control retarder 300 (such as Figure 9 those).

[0423] Figure 24A is a schematic diagram showing the brightness appearance of the mobile device in the public mode in perspective view, including Figure 1A display device 100 of and polarizing control retarder 300 of FIG. 23, and its appearance is shown in the clockwise order from the upper left: front lateral, front longitudinal, top longitudinal, and right view lateral.

[0424] The viewing direction along axis 199 of display device 100 is perpendicular to the viewing surface of display device 100. In all the shown orientations, in the public mode, the image emitted by display device 100 is visible to the observer, as represented by the white color representing the image emitted by display device 100. The image is visible in the lateral and longitudinal orientations 520 on all axes, top longitudinal orientation 522, and right view lateral orientation 528.

[0425] Figure 24B is a schematic diagram showing the brightness appearance of the mobile device in the privacy mode in perspective view, including Figure 1A display device 100 of and switchable polarizing control retarder 300 of FIG. 23, and its appearance is shown in the clockwise order from the upper left: front lateral, front longitudinal, top longitudinal, and right view lateral.

[0426] In the privacy mode, the field of view of the observer remains unchanged in the on-axis horizontal and vertical orientations 520, and the image emitted by the display device 100 is visible to the observer. However, in the top-down vertical orientation 522 and the right-side horizontal orientation 528, the image emitted by the display device is no longer visible. Instead, a snooper observing from a wide angle observes the mirror-like surface provided by the reflective polarizer 302 as described above.

[0427] Figure 24C FIG. is a schematic diagram illustrating the reflectance appearance of a mobile device in the privacy mode, including Figure 1A the display device 100 of FIG. and the switchable polarization control retarder 300 of FIG. 23, the appearance of which is shown in a clockwise order from the upper left: front horizontal, front vertical, top-down vertical, and right-side horizontal.

[0428] In the privacy mode, due to the minimum reflectance from the additional polarizer 318, the field of view of the observer remains unchanged in the on-axis horizontal and vertical orientations 520. However, in the top-down vertical orientation 522 and the right-side horizontal orientation 528, the reflection from the surface of the additional polarizer 318 can produce the front-end reflection as described above, thereby ideally increasing the visual safety level VSL.

[0429] Figure 25A FIG. is a schematic diagram illustrating a motor vehicle 600 having a switchable directional display 100 disposed within a vehicle cockpit 602 in a night operation mode.

[0430] The night mode of the switchable directional display 100 may correspond to the privacy mode discussed above. A light cone 620 (e.g., representing a light cone with a brightness greater than 50% of the peak brightness emitted by the switchable directional display 100) may indicate the angular range within which the image emitted by the switchable directional display 100 is distinguishable. As Figure 25A shown, when the switchable directional display 100 is in the night mode, the driver 604 is within the region defined by the light cone 620 in the horizontal direction, and the image emitted by the switchable directional display 100 is thus distinguishable to the driver 604. In contrast, the high-angle light rays 622 falling outside the light cone 620 in the horizontal direction have a reduced brightness, and thus the image emitted by the switchable directional display 100 may not be distinguishable to the passengers 608 in the vehicle 600. This may be advantageous if the passengers are trying to sleep or relax at night.

[0431] In this arrangement, if the visibility of a certain image to other users is acceptable, the reflective polarizer 302 can be omitted. Advantageously, the display efficiency can be increased and the visibility of stray light can be reduced.

[0432] Figure 25BSchematic diagram illustrating a motor vehicle 600 with a switchable directional display 100 arranged in a vehicle cabin 602 in a nighttime operating mode in a top view.

[0433] In night mode, the volume 606 occupied by the driver's face is within the area defined by the light cone 620 in the vertical direction, and therefore the image emitted by the switchable directional display 100 is discernible to the driver in the volume 606. However, high-angle light rays 622 that fall outside the light cone 620 in the vertical direction can have reduced brightness in the night mode of operation. The brightness of high-angle light rays 622 that can be reflected from the windshield 618 of the motor vehicle 600 can be reduced. This can advantageously reduce the reflection of the display 100 perceived by the driver on the windshield 618 in the volume 606.

[0434] There is a need to provide increased uniformity for rotation of display 100 about a horizontal axis and to relax alignment tolerances between parallax barrier 700 and pixel layer 214 .

[0435] Figure 26 is a schematic diagram illustrating in side perspective view a switchable privacy display 100 for ambient lighting 604, including an OLED emissive spatial light modulator 48, a one-dimensional parallax barrier 700, an output polarizer 218 and a reflective controlled quarter wave retarder 228, a reflective polarizer 302, a switchable polarity controlled retarder 300, and an additional polarizer 318 disposed on the output side of the spatial light modulator 48; and Figure 27 This is a front view illustration. Figure 26 Schematic diagram of the alignment of the optical layers in an optical stack. It can be assumed that Figures 26 - 27 Features of the arrangement correspond to features as discussed above with equivalent reference numerals, including any potential variations in features.

[0436] The polarity control delay device 300 is Figure 22A -Description in B.

[0437] The parallax barrier 700 forms a one-dimensional array of apertures 702 , with the pixels 220 , 222 , 224 arranged in columns, with each column of pixels 220 , 222 , 224 aligned with a respective aperture.

[0438] Pixels 220, 222, 224 have light-emitting areas extending in the direction in which hole 702 extends; the width of the red, green and blue light-emitting areas is the same for each pixel 220, 222, 224; and the height of the light-emitting areas is different for red, green and blue light-emitting pixels 220, 222, 224.

[0439] Advantageously, the switchable privacy display can have high image visibility for off-axis users in the horizontal direction and high visual security for off-axis snoops in the horizontal direction in the public mode and the privacy mode, respectively. The viewing freedom of rotation about the horizontal axis can be increased. Advantageously, the front user position can be conveniently adjusted with high luminance uniformity in the elevation angle direction.

[0440] In addition, compared with the arrangement in which the alignment is controlled on the lateral, vertical, and orientation axes Figure 1A the alignment of the parallax barrier 700 with the pixel layer can be controlled on the lateral and orientation axes. Advantageously, the yield can be increased and the cost can be reduced.

[0441] It is necessary to increase the efficiency of the display 100 while providing a low reflectance of light from the reflective pixel layer 214.

[0442] Figure 28 FIG. 12 is a schematic side view illustrating a switchable privacy display 100 for ambient lighting 604, including a micro-LED emitting spatial light modulator 48, a parallax barrier 700, and an output polarizer 218 as a reflective polarizer 302, a reflective control quarter-wave retarder 228, a switchable polarity control retarder 300, and an additional polarizer 318 disposed on the output side of the spatial light modulator 48; and Figure 29 FIG. 13 is a schematic side view illustrating the reflection of ambient light in the display 100 in Figure 28 It can be assumed that the features of the arrangement not further discussed in detail Figures 28 - 29 correspond to the features with equivalent reference numerals as discussed above, including any potential variations in the features.

[0443] Compared with Figure 1A and 17A the arrangement, reflective output polarizers 218, 302 are provided. The absorptive polarizer 218 is omitted, so that advantageously the transmittance of the display is increased, thereby achieving increased luminance and reduced power consumption for the desired image brightness.

[0444] Compared with Figure 14 the embodiment, the light rays 760 from the ambient light source 604 have a polarization state that is substantially reflected from the reflective output polarizers 218, 302 to provide light rays 762 that are absorbed by the absorptive regions 704 of the parallax barrier 700. The light rays 764 transmitted by the reflective polarizers 218, 302 are absorbed by the polarizer 318. Advantageously, the reflection of the ambient light 760 is reduced.

[0445] It is necessary to provide a low-reflectance display with high efficiency.

[0446] Figure 30A schematic diagram showing a low-reflectivity display 200 for ambient lighting 604 in a side perspective view, including an OLED emitting spatial light modulator 48, a two-dimensional parallax barrier 700, a leakage output polarizer 218, and a reflection control quarter-wave retarder 228 arranged on the output side of the spatial light modulator 48; and Figure 31 A schematic diagram showing the reflection of ambient light in the display 200 in a side view in Figure 30 The features of the arrangement that are not further discussed in detail can be assumed to correspond to the features with equivalent reference numerals as discussed above, including any potential variations in the features. Figures 30 - 31

[0447] The reflectivity control display 200 device for ambient lighting includes the display 200, where the parallax barrier 700 absorbs at least some of the ambient lighting 604.

[0448] Compared with Figure 1A the arrangement, the display 200 does not provide a privacy display 100. For example, the output can be provided as illustrated in Figure 21A -B and in the illustrative embodiment in the fourth row of Table 5, such that the aperture ratio of the holes 702 is 25% and the transmittance of the absorption region 704 of the parallax barrier 700 is 5%. The polarizer 218 includes, for example, Figure 15 the leakage polarizer as illustrated in. Advantageously, compared with the arrangement with a high extinction type polarizer, the output efficiency in the front direction is increased.

[0449] A touch sensor for the low-reflectivity display 200 needs to be provided.

[0450] Figure 32 A schematic diagram showing a touch screen low-reflectivity display 200 for ambient lighting 604 in a side perspective view, including an OLED emitting spatial light modulator 48, a two-dimensional parallax barrier 700 including a touch sensor electrode layer, a leakage output polarizer 218, and a reflection control quarter-wave retarder 228 arranged on the output side of the spatial light modulator 48; Figure 33 A schematic diagram showing the reflection of ambient light in the display 200 in a front view in Figure 32 ; and Figure 34 A schematic diagram showing the structure of Figure 32 in a side view. The features of the arrangement that are not further discussed in detail can be assumed to correspond to the features with equivalent reference numerals as discussed above, including any potential variations in the features. Figures 32 - 34

[0451] ​​An array of holes 702 is formed on the touch sensor electrode array 500. The position of the finger 25 at or near the protective cover layer 320 is detected by the touch electrode arrays 500, 502, the touch drivers 452, 454, and the touch control system 450. The touch electrode array 500 may be formed on the surface of the parallax barrier 700 or on the surface of the quarter-wave retarder.

[0452] The pair of touch electrode arrays 500, 502 are arranged in layers separated by a dielectric layer 504. The dielectric layer 504 is arranged between the switchable liquid crystal layer 314 and the additional polarizer 318. The first touch electrode array 500 and the second touch electrode array 502 are arranged on the dielectric layer 504 and on opposite sides of the dielectric layer 504.

[0453] The touch electrode arrays 500, 502 are arranged between the pixel layer 214 and the parallax barrier 700, or as Figure 32 illustrated in, arranged between the parallax barrier 700 and the quarter-wave reflection control retarder 228.

[0454] The touch input display device 100 further includes a control system 450, wherein the control system 450 is arranged to address the touch electrode arrays 500, 502 for capacitive touch sensing.

[0455] The control system 450 is further arranged to address the SLM 48. The control system includes a system controller, which is arranged to control the application to and measurement from the touch electrode arrays 500, 502 through the touch drivers 452, 454.

[0456] The electrodes 500, 502 are arranged between the holes 702 of the parallax barrier. Advantageously, high efficiency can be achieved.

[0457] In other embodiments as Figure 34 illustrated in, at least one absorption region 704 of the parallax barrier 700 includes the touch sensor electrode array 502. Advantageously, the touch sensor electrode arrays 500, 502 can have a reduced reflectivity. In addition, touch electrodes 504 can be provided at the pixel layer 214.

[0458] In other embodiments (not shown), the touch sensing electrode layer may be arranged at the pixel layer 214. Advantageously, the control of the sensing electrodes can be provided together with the control of the pixel data, thereby reducing cost and complexity.

[0459] It is further desirable to achieve increased transmission efficiency.

[0460] Figure 35ASchematic diagram showing a low-reflectance display 200 for ambient lighting 604 in a side perspective view, including an OLED emissive spatial light modulator 48, a two-dimensional parallax barrier 700, and an output polarizer not arranged on the output side of the spatial light modulator; and Figure 35B Schematic diagram showing in a side view the reflection of ambient light in the display 200 of Figure 35A It can be assumed that the features of the arrangement of -B not further discussed in detail correspond to the features with equivalent reference numerals as discussed above, including any potential variations in the features. Figure 35A -B's arrangement features corresponding to those with equivalent reference numerals as discussed above, including any potential variations in the features.

[0461] Compared with Figure 30 the embodiment of, the output polarizer 218 is omitted. Advantageously, the efficiency is increased.

[0462] Ambient light rays 410, 412 are absorbed by the absorption region 704, while the output light rays 710 in the normal direction are transmitted without loss. High-angle light rays 712 from the pixels 220 are further absorbed. Thus, some ambient light is absorbed, thereby advantageously increasing the image contrast.

[0463] It is necessary to further reduce the reflectance of ambient light.

[0464] Figure 36A Schematic diagram showing a low-reflectance display for ambient lighting in a side perspective view, including an OLED emissive spatial light modulator, two one-dimensional parallax barriers 700A, 700B, and an output polarizer not arranged on the output side of the spatial light modulator 48; and Figure 36B Schematic diagram showing in a side view the reflection of ambient light in the display of Figure 36A It can be assumed that the features of the arrangement of -B not further discussed in detail correspond to the features with equivalent reference numerals as discussed above, including any potential variations in the features. Figure 36A -B's arrangement features corresponding to those with equivalent reference numerals as discussed above, including any potential variations in the features.

[0465] The barriers 700A, 700B can be arranged on separate substrates 216A, 216B that provide the spacing of the barriers. Light can be trapped within the substrate 216B and absorbed.

[0466] Compared with Figure 35A the embodiment of -B, the alignment tolerances of each of the barriers 700A, 700B can be relaxed, thereby increasing the yield and reducing the cost. In addition, additional high light rays 713 can be absorbed, thereby reducing the leakage between pixels. Advantageously, the image contrast can be increased.

[0467] It may be necessary to reduce the off-axis light from the emitting pixels and increase the efficiency in the forward direction.

[0468] Figure 37AFIG. is a schematic diagram showing an array of reflective-refractive optical elements arranged between pixels 220, 222, 224 of a spatial light modulator 48 and a parallax barrier 700 in a side view; and Figure 37B is a schematic diagram showing the change in output luminance with Figure 37A the polar angle of the arrangement of. It can be assumed that the features of the arrangement not further discussed in detail Figure 37A correspond to the features with equivalent reference numerals as discussed above, including any potential variations in the features.

[0469] The reflective-refractive optical elements for an emissive display are described in WIPO Publication No. WO 2019 / 138243 (Attorney Docket No. 442002), which is incorporated herein by reference in its entirety.

[0470] The reflective-refractive optical structure 800 is aligned with the emissive pixels 220, 222, 224 to provide a directional light output distribution from the spatial light modulator 48 that is similar to Figure 11A or Figure 19A the directional light output distribution illustrated in. The reflective-refractive optical structure 800 includes a plurality of reflective-refractive optical elements 838 arranged in an array of reflective-refractive optical elements. Each of the plurality of reflective-refractive optical elements 838 in the plurality of reflective-refractive optical elements 800 is correspondingly aligned with one or more of the corresponding pixels of the plurality of pixels 220, 222, 224. Each of the pixels of the plurality of LEDs is aligned only with a corresponding one of the reflective-refractive optical elements 838 of the reflective-refractive optical structure 800.

[0471] Each of the plurality of reflective-refractive optical elements 838 includes a first cross-sectional outer interface 804A and a second cross-sectional outer interface 804B facing the first cross-sectional outer interface 804A in at least one reflective-refractive cross-sectional plane passing through its optical axis 199.

[0472] The first cross-sectional outer interface 804A and the second cross-sectional outer interface 804B each include a curved interface that includes a first outer interface region 840 and a second outer interface region 842.

[0473] The first cross-sectional outer interface 804A and the second cross-sectional outer interface 804B extend from a first end of the reflective-refractive optical element 838 to a second end of the reflective-refractive optical element 838. The second end of the reflective-refractive optical element 838 faces the first end of the reflective-refractive element.

[0474] The distance between the first and second cross-sectional outer interfaces at the first end of the reflective-refractive optical element located at the pixel layer is less than the distance between the first and second cross-sectional outer interfaces 804A, 804B at the second end of the reflective-refractive optical element 838 at the output side of the reflective-refractive optical element 838.

[0475] At least one transparent internal interface 810 is disposed between the first and second ends and between the first and second external interfaces 804A, 804B.

[0476] The reflective refraction optical structure 838 includes: (i) a first transparent non-gaseous material having a first refractive index, which is disposed between the first and second cross-sectional external interfaces and at least one transparent internal interface and between the first and second ends of each of the reflective refraction optical elements; (ii) a second transparent non-gaseous material having a second refractive index less than the first refractive index, which is disposed between the corresponding aligned pixels 220, 222, 224 and the transparent internal interfaces of each of the reflective refraction optical elements; (iii) a third transparent non-gaseous material having a third refractive index less than the first refractive index, which is disposed between the first cross-sectional external interface of the first reflective refraction optical element and the second cross-sectional external interface of an adjacent reflective refraction optical element among the plurality of reflective refraction optical elements, and between the first and second ends of each of the reflective refraction optical elements.

[0477] The tilt angle of the optical axis 199 with respect to the interface normal of each of the first cross-sectional external interface 804A and the second cross-sectional external interface 804B varies continuously with the distance c from the first end towards the second end. The derivative of the tilt angle with respect to the distance ξ from the optical axis 199 has a discontinuity at the boundary 844 between the corresponding first and second external interface regions 840, 842 of the first and second cross-sectional external interfaces 804A, 804B.

[0478] The materials 802, 814 can be transparent and are conveniently provided in the layer 800, thereby reducing manufacturing costs and complexity.

[0479] Embodiments of the present invention achieve encapsulation of OLED pixels through a solid reflective refraction optical element 838 having interfaces 804A, 804B, which are arranged to advantageously achieve directional illumination with low-level crosstalk to snoops. Figure 37B The curve 850 can be provided by the illustrative embodiments of Table 8.

[0480]

[0481] Table 8

[0482] Most of the main light rays 820 in the second external interface region 842 are guided by total internal reflection in a direction nearly parallel to the optical axis 199, thereby providing a high level of collimation for the light rays reflected from the outer surfaces 804A, 804B. The light rays 822 incident on the region 840 are guided in a direction close to but different from the collimation direction of the known low-cost materials in the solid reflective refraction optical element 38.

[0483] Advantageously, losses are reduced and the efficiency of the on-axis light is increased.

[0484] In other embodiments, the interface 804 may be provided by a metal surface to provide some collimation of the output light.

[0485] There is a need to reduce the number of light rays at higher polar angles. The absorption region 704 of the parallax barrier 700 may be arranged to reduce the brightness at higher polar angles.

[0486] In other embodiments, the shapes of the surfaces 804A, 804B may be arranged to provide controlled light rays at high polar angles to achieve increased brightness at higher polar angles, such as between 2.5% and 15% of the front brightness. A common-mode brightness with high image visibility may be provided. The polarizers 218, 318 and the polarization control retarder 300 may be arranged to achieve switching between the common mode and the privacy mode. Other pixels may be arranged on the pixel layer between the reflective refractive optical elements 838 to achieve increased light at high polar angles, as described in WO 2018 / 185475 (Agent Ref. No. 439002), which is incorporated herein by reference in its entirety.

[0487] A method of manufacturing a display device according to an embodiment of the present invention will now be described.

[0488] Figure 38A -D is a schematic view showing a method of manufacturing the parallax barrier 700 of the emissive displays 100, 200 using a fine metal mask 900 in a side view.

[0489] Figure 38A It is illustrated that in a first step, an array of emissive pixels 220, 222, 224 is formed on the backplane by guiding the emissive material 802 through the fine metal mask. For example, the structure of the pixels 220, 222, 224 is further described in Figure 6 The structure of the pixels 220, 222, 224 is further described in.

[0490] Figure 38B It is illustrated that in a second step, an inorganic layer 752 and an organic layer 750 are added to provide the substrate 216 as an encapsulation layer for the pixel layer 214. The step of forming the encapsulation layer on the array of emissive pixels 220, 222, 224 thus includes forming at least one transparent inorganic layer 752. The at least one transparent inorganic layer may be a glass layer. By chemical mechanical polishing of a thicker glass layer, the glass layer may have an appropriate thickness d. The organic layer 750 may be omitted. An adhesive layer 244 may be provided between the pixel layer 214 and the substrate 216.

[0491] Figure 38CIt is described that a parallax barrier 700 including an array of holes 702 is formed on the surface of the encapsulation layer substrate 216 by guiding a light-absorbing material 903 through a fine metal mask 904. The mask 904 may be the same as the mask 900. The alignment of the mask 904 is shifted in the lateral position relative to the alignment of the mask 900 to achieve alignment of the holes 702 with the centers of the pixels 220, 222, 224.

[0492] Figure 38D It is described that the barrier is formed on the layer 216 before arranging layers such as other encapsulation layers, a reflection-reducing retarder 228, polarizers 218, 318, and a polarization control retarder 300 on the parallax barrier.

[0493] Advantageously, similar devices and masking techniques used to form the pixels 220, 222, 224 can be used to form the parallax barrier 700. The cost of applying the parallax barrier 700 can be advantageously reduced.

[0494] The pixels 220, 222, 224 have a pitch p along the direction closest to the holes 702, the material between the parallax barrier 700 and the pixels 220, 222, 224 has an overall refractive index n, and the encapsulation layer has a thickness d that meets the requirements The holes 702 have a width a along the direction closest to the holes 702, the material between the parallax barrier 700 and the pixels 220, 222, 224 has an overall refractive index n and the encapsulation layer has a thickness d that meets the requirements and preferably meets the requirements of.

[0495] A high-precision lithography is required to provide the parallax barrier.

[0496] Figure 39A -F is a schematic view showing a method of manufacturing a parallax barrier 700 of an emissive display using lithography in a side view.

[0497] A method of forming a display device includes the following steps: forming an array of emissive pixels 220, 222, 224 on a backplane by guiding an emissive material through a fine metal mask, the fine metal mask forming an encapsulation layer including at least one transparent inorganic layer on the array of emissive pixels 220, 222, 224; forming a parallax barrier 700 including an array of holes 702 on the surface of the encapsulation layer by lithographic patterning.

[0498] In the first and second steps, an emissive display is provided as illustrated in Figure 38A -B.

[0499] Figure 39A It is described that in the third step, a barrier material 904 is formed on the upper surface of the layer 216.

[0500] Figure 39B It is illustrated that in the fourth step, the photolithography masking material 906 is disposed on the upper surface of the material 904.

[0501] Figure 39C It is illustrated that in the fifth step, the photomask 908 is aligned with the pixels 220, 222, 224 and exposed to the UV radiation 910.

[0502] Figure 39D It is illustrated that in the sixth etching step, the material 904 is removed.

[0503] Figure 39E It is illustrated that in the seventh step, the photolithography material is removed.

[0504] Figure 39F It is illustrated the final device after adding another encapsulation layer.

[0505] Advantageously, a high-resolution and accurately aligned parallax barrier can be provided, thereby reducing costs and complexity and providing the highest brightness in the normal direction aligned with the axis 199.

[0506] It may be necessary to provide the parallax barrier on a separate layer and align it with the spatial light modulator 48.

[0507] Figure 40A -D is a schematic view illustrating a method of using printing to fabricate the parallax barrier 700 of the emissive displays 100, 200 in a side view.

[0508] Figure 40A It is illustrated that a printing method such as inkjet printing, photolithography, flexographic printing or other known printing techniques can be used to provide the parallax barrier 700 to apply the absorbing material to the region 704. The parallax barrier 700 can be disposed on the substrate 110.

[0509] Figure 40B It is illustrated that the parallax barrier can be aligned with the pixel layer 214. The material 246 is input into the gap between the substrate 216 and the parallax barrier 700.

[0510] Figure 40C It is illustrated the device structure after curing the adhesive material 246.

[0511] Figure 40D It is illustrated that the substrate 110 is thinned, for example, by chemical mechanical polishing of the substrate 110.

[0512] Advantageously, the parallax barrier can be formed after manufacturing the emissive display.

[0513] It can be assumed that those not further discussed in detail Figure 38A -D, Figure 39A -F and Figure 40AThe features of the arrangement of -D correspond to the features with equivalent reference numerals as discussed above, including any potential variations in the features.

[0514] There is a need to provide an emissive privacy display with increased front efficiency and reduced off-axis brightness.

[0515] Figure 41 FIG. is a schematic side view illustration of a switchable privacy display 100 for ambient lighting, including an OLED emissive spatial light modulator 48 containing tangible OLED pixels 220, 222, 224, an output polarizer 218, and a reflective control quarter-wave retarder 228, a reflective polarizer 302, a switchable polarity control retarder 300, and an additional polarizer 318 disposed on the output side of the spatial light modulator 48; and Figure 42 FIG. is a schematic side view illustration of a pixel of the OLED emissive spatial light modulator 48, where the OLED pixels 220, 222, 224 are tangible OLED pixels including a tangible well 272 and a high refractive index filling material 270. It can be assumed that Figures 41 - 42 The features of the arrangement correspond to the features with equivalent reference numerals as discussed above and below, including any potential variations in the features.

[0516] The structure and operation of one of the pixels 220 will now be described.

[0517] Figure 43 FIG. is a schematic side view illustration of a pixel of the OLED emissive spatial light modulator, where the OLED pixel includes a tangible well 272 and a high refractive index filling material 270. The pixel 220 is driven by a pixel circuitry 249 including electrodes 243, 245 and layers 241, 251, 253 including semiconductors and dielectrics to provide transistors, capacitors, and other drive circuitry elements. As Figures 6 - 7 illustrated in, a via 242 is arranged to connect to an electrode 234, which in turn contacts a rear reflector 240, which can be, for example, a silver electrode. An electron transport layer 236, an emissive layer 232, a hole transparent electrode layer 238, and a transparent electrode 244 are disposed on the electrode 234 to implement the emissive pixel 220.

[0518] The pixel 220 has a well profile 272 and can further have a planar surface or a curved surface, the well profile having a central region 273 that can be substantially planar and a sloped inclined region 271.

[0519] The filling material 270 is disposed between the inclined regions 271. The filling material can have, for example, a refractive index of approximately 1.8. The refractive index of the filling material can be similar to the refractive index of the emissive layer 232 material.

[0520] In operation, light is provided by source 269, which has an angular distribution of luminous intensity determined by the wavelength, reflection of the reflective layer, interference between coherent wavefronts, guiding within the layer, and surface plasmon absorption in the metal layer. Such propagation characteristics are commonly referred to as the microcavity emission effect.

[0521] In an embodiment of the present invention, the light ray 276 emitted towards the normal direction is directly output without being incident on the outer region 271 of the pixel 220. The light ray 274 is output after being incident on the reflective layer of the inclined region 271. The light ray 276 is guided within the filling material 270 and output after being incident on the inclined region 271.

[0522] Advantageously, the light rays 274 and 276 that would be lost by guiding in the cover layer 246 are guided in the forward direction. Compared with the arrangements described elsewhere, the parallax barrier 700 can be omitted and the cost can be reduced. In other embodiments, tangible pixels (not shown) and the parallax barrier 700 can be provided. Advantageously, the efficiency is increased and the off-axis visual safety level is increased for the privacy operation mode. Figures 41 - 43 Advantageously, the efficiency is increased and the off-axis visual safety level is increased for the privacy operation mode.

[0523] Returning to Figure 42 For the red, green, and blue pixels 220, 222, and 224, the profiles of the inclined region 271 may be different. Such differences can compensate for the different color attenuations of the microcavity interference effect. Advantageously, the color uniformity can be improved.

[0524] Figure 44 is a schematic diagram illustrating the variation of the luminous intensity of tangible and intangible OLED pixels. Compared with the curve of luminance versus polar angle, a curve of luminous intensity versus azimuth angle is provided. Therefore, the Lambertian output curve 280 has a cosθ curve. Curves 282 for conventional OLED pixels and the desired curves 284 and 286 that can be provided by the tangible pixel 220 having the inclined region 271 are provided. Ideally, the luminous intensity at a polar angle of at least 45 degrees is less than 15% of the maximum luminous intensity, and preferably less than 10% of the maximum luminous intensity. Additionally, the maximum luminous intensity at a polar angle of at least 60 degrees is less than 7.5% of the maximum luminous intensity, and preferably less than 5% of the maximum luminous intensity.

[0525] Figure 45A is Figure 41 a polar plot array of the component weights and outputs of the arrangement, including Figure 44 the spatial light modulator luminance, switchable retarder transmittance, switchable retarder reflectance, common mode luminance, privacy mode luminance, and polar plot of the visual safety level of the luminous intensity curve 286 in Figure 45B is Figure 45AGraph arrays of component weights and outputs of the arrangement, including linear curves at azimuth angles of 0, 90, 45, and 225 degrees.

[0526] The tangible OLED pixels 220, 222, 224 are arranged to provide increased front brightness and reduced off-axis brightness. Advantageously, the visual security level is increased for off-axis snoops in the privacy operation mode. Additionally, the output efficiency is increased for front users.

[0527] It may be necessary to provide a display that provides privacy features in both landscape and portrait operation modes.

[0528] Figure 46 FIG. is a schematic side perspective view illustrating a switchable privacy display device 100 for ambient lighting 604, including an emissive spatial light modulator 48, a parallax barrier 700, a first polarization control retarder 300A disposed between a display polarizer 218 of the emissive spatial light modulator 48 and a first additional polarizer 318A; and a reflective polarizer 302 and a second polarization control retarder 300B disposed between the first additional polarizer 318A and a second additional polarizer 318B.

[0529] Figure 47A FIG. is a front perspective view illustrating Figure 46 a schematic diagram of the arrangement of polarizers and polarization control retarders for an embodiment of, where the first and second polarization control retarders cross and the spatial light modulator includes a parallax barrier 700. In this embodiment, the liquid crystal alignment in the switchable polarization control retarder 301A is provided by a vertical alignment layer having an alignment direction 419AAz with a pretilt direction 419AAy and a horizontal alignment layer having a pretilt direction 419AB, where the directions 419AAy, 419AB are anti-parallel; and the liquid crystal alignment in the switchable polarization control retarder 301B is provided by a vertical alignment layer having an alignment direction 419BAz with a pretilt direction 419BAy and a horizontal alignment layer having a pretilt direction 419BB, where the directions 419BAy, 419BB are anti-parallel and the directions 419AAy, 419AB are perpendicular to the directions 419BAy, 419BB.

[0530] It can be assumed that the features of the embodiments of Figure 47A not further discussed in detail correspond to the features with equivalent reference numerals as discussed above, including any potential variations in the features.

[0531] Figure 47B FIG. illustrates the emission spatial light modulator without Figure 46 a graphical representation of the simulated polarization curves of the brightness output of the barrier structure 700.

[0532] Figure 47CIt is a graph showing the simulated polarization curve of the transmittance of the barrier structure of FIG. 2 that illustrates the light from the pixels of the emission spatial light modulator. Illustrative examples are provided in Table 9, where the emission spatial light modulator 48 and the aligned parallax barrier 700 have an output luminance curve having a full width at half maximum of up to 40 degrees.

[0533] Parameter, x - axis direction Illustrative value Pixel 224 pitch 20 microns Pixel 224 emission width 10 microns Barrier hole 702 width 10 microns Barrier spacing, d 20 microns

[0534] Table 9

[0535]

[0536] Table 10

[0537] Figure 47D It is a graph showing the simulated polarization curve of the transmittance of the Figure 47A and the second polarization control retarder of Table 10 arranged between the first and second additional polarizers, where the electric vector transmission directions of the polarizers are parallel; Figure 47E It is a graph showing the simulated polarization curve of the reflectance of the Figure 47A and the second polarization control retarder of Table 10 arranged between the reflective polarizer and the second additional polarizer, where the electric vector transmission directions of the polarizers are parallel; Figure 47F It is a graph showing the simulated polarization curve of the total reflectance including Figure 47E and the reflectance of Table 10 and the Fresnel reflectance from the front surface of the display device; Figure 47G It is a graph showing the simulated polarization curve of the transmittance of the Figure 47A and the first polarization control retarder of Table 10 arranged between the display polarizer and the first additional polarizer, where the electric vector transmission directions of the polarizers are parallel; and Figure 47H It is a graph showing the simulated polarization curve of the logarithm of the total output luminance of the Figure 47A spatial light modulator and the first and second polarization control retarders.

[0538] Figure 47I It is a graph showing the simulated polarization curve of the Figure 47A , Table 9 and Table 10 for the security level S with respect to the ambient illuminance measured in lux in the privacy mode, where the ambient illuminance is twice the front display luminance measured in nits. Advantageously, the emission display can have a polarization curve of the security level required for both horizontal and vertical operations.

[0539] Figure 47J It is a graph showing the simulated polarization curve of the Figure 47A, Tables 9 and 10 are arranged in a privacy mode for a simulated polarity curve of safety level S for an ambient illuminance measured in lux that is twice the front display brightness measured in nits. In public mode, the output is determined by multiplying curve 47B by curve 47C. Figure 47J The safety factor is described in . Advantageously, the safety factor S is less than 0.1 over a wide polar angle range, so that the image can be clearly seen on the display.

[0540] As an alternative to the embodiment of Table 10, the retardation and alignment layers of the first and / or second polarity controlled retarders 301A, 301B may be provided by two horizontal alignment layers or two vertical alignment layers. Compared to the arrangement of Table 10, the polarity range with a high safety factor and the resilience to applied pressure may be modified to achieve desired alternative characteristics.

[0541] As may be used herein, the terms "substantially" and "approximately" provide an industry-accepted tolerance for the terms and / or correlations between items to which they correspond. Such industry-accepted tolerances range from zero to ten percent and correspond to, but are not limited to, component values, angles, etc. Such correlations between items range from approximately zero to ten percent. As may be used herein, a term describing the "direction in which the holes are closest" refers to the direction in which the smallest distance between holes extends. Similarly, a term describing the "direction in which the pixels are closest" as may be used herein refers to the direction in which the smallest distance between pixels extends.

[0542] Although various embodiments according to the principles disclosed herein have been described above, it should be understood that these embodiments are presented only as examples and not limitations. Therefore, the breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments, but should only be defined in accordance with any claims and their equivalents issued from the present disclosure. In addition, the above-described advantages and features are provided in the described embodiments, but the application of such issued claims should not be limited to processes and structures that achieve any or all of the above-described advantages.

[0543] In addition, the section headings provided herein are for consistency with the recommendations under 37 CFR 1.77 or to provide organizational cues. These headings should not limit or characterize the embodiments set forth in any claims that may be issued from this disclosure. Specifically and by way of example, although the heading refers to a "Technical Field", the claims should not be limited by the language selected under the heading to describe the so-called field. Further, the technical descriptions in the "Background Art" should not be construed as admitting that certain techniques are prior art to any embodiments in this disclosure. The "Summary of the Invention" is also not considered to be a characteristic of the embodiments set forth in the issued claims. Additionally, any reference in this disclosure to the singular form of the "invention" should not be used to argue that there is only a single novel point in this disclosure. Multiple embodiments may be set forth in accordance with the limitations of the multiple claims issued from this disclosure, and such claims accordingly define the embodiments protected thereby and their equivalents. In all cases, the scope of these claims should be considered in light of this disclosure on its own merits and should not be limited by the headings set forth herein.

Claims

1. A display device, the display device comprising: a transmissive spatial light modulator, the transmissive spatial light modulator including an array of pixels arranged in a pixel layer; and a parallax barrier, the parallax barrier forming a two-dimensional array of holes, wherein the parallax barrier is spaced from the pixel layer by a parallax distance along an axis normal to the plane of the pixel layer, and each pixel is aligned with a corresponding hole in the two-dimensional array of holes.

2. The display device according to claim 1, wherein the parallax barrier guides light from each pixel into a common viewing window.

3. The display device according to claim 1 or 2, wherein along the direction in which the minimum distance between the holes extends, the holes have a width a and the pixels have a width w satisfying the requirement a≥w.

4. The display device according to claim 1, wherein along the direction in which the minimum distance between the holes extends, the holes have a width a, the pixels have a pitch p, and the pixels have a width w satisfying the requirement a≤(p - w / 2).

5. The display device according to claim 1, wherein the parallax barrier has a spacing d from the pixels, and the pixels have a pitch p in a direction along which the minimum distance between the holes extends, and the material between the parallax barrier and the pixels has a refractive index n satisfying the requirements thereof.

6. The display device according to claim 1, wherein the parallax barrier has a spacing d from the pixels, and the holes have a width a in a direction along which the minimum distance between the holes extends, and the material between the parallax barrier and the pixels has a refractive index n that satisfies the requirements .

7. The display device according to claim 6, wherein the parallax barrier has a spacing d from the pixels, and the holes have a width a in the direction in which the minimum distance between the holes extends, and the material between the parallax barrier and the pixels has a refractive index n that satisfies the requirement s.

8. The display device according to claim 1, wherein the parallax barrier has a pitch p', the pitch p' being the distance between the centers of adjacent holes along the direction in which the minimum distance between the holes extends, wherein the pitch p' is less than the pitch p of the corresponding aligned pixels along the direction in which the minimum distance between the pixels extends; and a viewing window is formed at a viewing window plane on the output side of the transmissive spatial light modulator.

9. The display device according to claim 1, wherein the pixels are arranged in columns and rows, the direction in which the minimum distance between the holes extends is at 45 degrees with respect to the electric vector transmission direction of the output linear polarizer; and each pixel has a light-emitting region in the shape of a square, wherein the edges are rotated 45 degrees with respect to the electric vector transmission direction of the output linear polarizer.

10. The display device according to claim 9, wherein the holes have a square shape, wherein the edges are rotated 45 degrees with respect to the electric vector transmission direction of the output linear polarizer; or the holes have a circular shape.

11. The display device according to claim 9, wherein for at least some of the pixels, the light-emitting region includes a light-emitting sub-region and a non-light-emitting sub-region.

12. The display device according to claim 11, wherein the area ratio of the light-emitting sub-region to the non-light-emitting region is different for red, green, and blue pixels.

13. The display device according to claim 1, wherein each pixel has a light-emitting region extending in the direction in which the holes extend; the widths of the red, green, and blue light-emitting regions are the same for each of the pixels; and the heights of the light-emitting regions are different for red, green, and blue light-emitting pixels.

14. The display device according to claim 1, wherein the parallax barrier is arranged to absorb light incident thereon.

15. The display device according to claim 1, wherein the absorptivity of the region of the parallax barrier between the holes is less than 100%, and greater than 80%.

16. The display device according to claim 14 or 15, wherein the display device is for ambient lighting, and the parallax barrier absorbs at least some of the ambient lighting reflected from the pixel layer and transmitted through the holes.

17. The display device according to claim 1, wherein the display device has one or more additional layers between the pixel layer and the parallax barrier, and the pixels, the one or more additional layers, and the parallax barrier are formed as a monolithic stack.

18. The display device according to claim 17, wherein the one or more additional layers include at least one light-transmissive inorganic layer arranged to provide a barrier against water and oxygen.

19. The display device according to claim 1, wherein the parallax barrier includes at least one light-transmissive inorganic material arranged to provide a barrier against water and oxygen.

20. The display device according to claim 1, wherein the parallax barrier is arranged between the pixel layer and at least one light-transmissive inorganic layer, and the at least one light-transmissive inorganic layer is arranged to provide a barrier against water and oxygen.

21. The display device according to claim 1, wherein an output polarizer is arranged on the output side of the emission spatial light modulator, and the output polarizer is a linear polarizer; and a reflection control quarter-wave retarder is arranged between the output polarizer and the emission spatial light modulator.

22. The display device according to claim 21, wherein the parallax barrier is arranged between the pixel layer and the reflection control quarter-wave retarder.

23. The display device according to claim 1, the display device further includes an additional polarizer arranged on the output side of the output polarizer, and the additional polarizer is a linear polarizer; and at least one polarization control retarder, and the at least one polarization control retarder is arranged between the output polarizer and the additional polarizer.

24. The display device according to claim 21, wherein when crossed with a conceptual polarizer of the same material, the transmittance of at least one of the output polarizer and the additional polarizer for wavelengths from 520 nm to 560 nm is less than the transmittance for wavelengths from 450 nm to 490 nm.

25. The display device according to claim 24, wherein the transmittance for wavelengths from 450 nm to 490 nm is greater than 1%; and the transmittance for wavelengths from 520 nm to 560 nm is less than 3%.

26. The display device according to claim 23, wherein the at least one polarization control retarder further includes at least one passive retarder.

27. The display device according to claim 26, wherein the at least one polarization control retarder is capable of simultaneously performing the following operations: not introducing a net relative phase shift to the orthogonal polarization components of the light transmitted by the output polarizer along the axis normal to the plane of the at least one polarization control retarder, and introducing a relative phase shift to the orthogonal polarization components of the light transmitted by the reflection polarizer along the axis inclined to the normal of the plane of the at least one polarization control retarder.

28. The display device according to claim 26, wherein the at least one passive retarder includes a retarder having an optical axis perpendicular to the plane of the at least one passive retarder, and the retardation of the at least one passive retarder for light with a wavelength of 550 nm is in the range of -150 nm to -900 nm.

29. The display device according to claim 26, wherein the at least one polarization control retarder comprises: a first quarter-wave plate and a second quarter-wave plate arranged between the additional polarizer and the output polarizer, the first quarter-wave plate being arranged on the input side of the second quarter-wave plate and being arranged to convert the polarization state of linearly polarized light transmitted by the output polarizer on the input side of the first quarter-wave plate into a circularly polarized state, and the second quarter-wave plate on the output side being arranged to convert the polarization state of circularly polarized light incident thereon into a linearly polarized state transmitted by the additional polarizer on the output side of the second quarter-wave plate; and at least one retarder arranged between the pair of quarter-wave plates.

30. The display device according to claim 29, wherein the retarder arranged between the pair of quarter-wave plates includes a retarder having an optical axis perpendicular to the plane of the retarder, and the retardation of the at least one passive retarder for light with a wavelength of 550 nm is in the range of -150 nm to -500 nm.

31. The display device according to claim 23, wherein the at least one polarization control retarder includes a switchable liquid crystal retarder, and the switchable liquid crystal retarder includes a liquid crystal material layer and electrodes arranged to apply a voltage to switch the liquid crystal material layer.

32. The display device according to claim 31, wherein the at least one polarization control retarder is arranged such that: in a first switchable state of the switchable liquid crystal retarder, the following operations are performed simultaneously: no net relative phase shift is introduced to the orthogonal polarization components of the light transmitted by the reflective polarizer along the axis normal to the plane of the at least one polarization control retarder, and a net relative phase shift is introduced to the orthogonal polarization components of the light transmitted by the reflective polarizer along the axis inclined to the normal of the plane of the at least one polarization control retarder; and in a second switchable state of the switchable liquid crystal retarder, the following operations are performed simultaneously: no net relative phase shift is introduced to the orthogonal polarization components of the light transmitted by the reflective polarizer along the axis normal to the plane of the at least one polarization control retarder, and no net relative phase shift is introduced to the orthogonal polarization components of the light transmitted by the reflective polarizer along the axis inclined to the normal of the plane of the at least one polarization control retarder.

33. The display device according to claim 23, wherein the display device further includes a reflective polarizer disposed between the output polarizer and the at least one polarization control retarder, and the reflective polarizer is a linear polarizer configured to transmit a polarization component of the same linear polarization as the output polarizer.

34. The display device according to any one of claims 21 to 33, wherein the output polarizer is a reflective polarizer.

35. The display device according to claim 1, wherein the pixel includes a light-emitting diode.

36. The display device according to claim 35, wherein the light-emitting diode is an organic light-emitting diode including an organic light-emitting material.

37. The display device according to claim 36, wherein the thickness of the light-emitting material is different for each of the red, green, and blue light-emitting regions.

38. The display device according to claim 35, wherein at least some of the light-emitting diodes are inorganic micro light-emitting diodes.

39. The display device according to claim 38, wherein the hole has an absorption rate, and at the edge of the hole, the absorption rate has a transmittance gradient, and the transmittance gradient has a transmittance gradient width greater than 1 micron.

40. The display device according to claim 1, wherein the two-dimensional array of holes is formed on a touch sensor electrode array.

41. The display device according to claim 1, wherein at least one absorption region of the parallax barrier includes a touch sensor electrode array.

42. The display device according to claim 1, wherein color filters are included at least at some of the holes of the parallax barrier.

43. The display device according to claim 42, wherein the holes of the parallax barrier include an array of red, green, and blue color filters.

44. A reflectivity control display device for ambient lighting, the reflectivity control display device including a display device, the display device comprising: an emission spatial light modulator including an array of pixels disposed in a pixel layer; and a parallax barrier forming a two-dimensional array of holes, wherein the parallax barrier is spaced from the pixel layer by a parallax distance along an axis normal to the plane of the pixel layer, and each pixel is aligned with a corresponding hole in the two-dimensional array of holes, wherein the parallax barrier absorbs at least some of the ambient lighting.

45. The reflectivity control display device according to claim 44, wherein the parallax barrier guides light from each pixel into a common viewing window.

46. The reflectivity control display device according to claim 44, wherein the parallax barrier absorbs at least some of the ambient lighting reflected from the pixel layer.

47. The reflectivity control display device according to claim 45, wherein along the direction extending along the minimum distance between the holes, the hole has a width a and the pixel has a width w satisfying the requirement a≥w.

48. The reflectivity control display device according to claim 44, wherein along the direction extending along the minimum distance between the holes, the holes have a width a, the pixels have a pitch p, and the pixels have a width w satisfying the requirement a ≤ (p - w / 2).

49. The reflectivity control display device according to claim 44, wherein the parallax barrier has a spacing d from the pixels, and the pixels have a pitch p in a direction extending along the minimum distance between the holes, and the material between the parallax barrier and the pixels has a refractive index n satisfying the requirement s.

50. The reflectance control display device according to claim 49, wherein the hole has a width a in the direction in which the minimum distance between the holes extends, and the material between the parallax barrier and the pixel has a refractive index n that satisfies the requirement s.

51. The reflectivity control display device according to claim 44, wherein the parallax barrier has a pitch P, the pitch P being the distance between the centers of adjacent holes along the direction extending along the minimum distance between the holes, wherein the pitch P is less than the pitch p of the corresponding aligned pixels along the direction extending along the minimum distance between the pixels; and An observation window is formed at an observation window plane on the output side of the emission spatial light modulator.

52. The reflectivity control display device according to claim 44, wherein the pixels are arranged in columns and rows, The direction in which the minimum distance between the holes extends is 45 degrees with respect to the electric vector transmission direction of the output linear polarizer; and Each pixel has a light-emitting region in a square shape, wherein the edges are rotated 45 degrees with respect to the electric vector transmission direction of the output linear polarizer.

53. The reflectivity control display device according to claim 52, wherein the holes have a square shape, wherein the edges are rotated 45 degrees with respect to the electric vector transmission direction of the output linear polarizer; or the holes have a circular shape.

54. The reflectivity control display device according to claim 44, wherein the absorption rate of the region of the parallax barrier between the holes is less than 100%, and Greater than 80%.

55. The reflectivity control display device according to claim 44, wherein the display device has one or more additional layers between the pixel layer and the parallax barrier, wherein the pixels, the one or more additional layers, and the parallax barrier are formed as a monolithic stack.

56. The reflectivity control display device according to claim 55, wherein the one or more additional layers include at least one light-transmissive inorganic layer arranged to provide a barrier against water and oxygen.

57. The reflectivity control display device according to claim 44, wherein the parallax barrier includes at least one light-transmissive inorganic material arranged to provide a barrier against water and oxygen.

58. The reflectivity control display device according to claim 44, wherein the parallax barrier is arranged between the pixel layer and at least one light-transmissive inorganic layer, the at least one light-transmissive inorganic layer being arranged to provide a barrier against water and oxygen.

59. The reflectivity control display device according to claim 44, wherein an output polarizer is arranged on the output side of the emission spatial light modulator, the output polarizer being a linear polarizer; and A reflection control quarter-wave retarder is arranged between the output polarizer and the emission spatial light modulator.

60. The reflectivity control display device according to claim 59, wherein the parallax barrier is arranged between the pixel layer and the reflection control quarter-wave retarder.

61. The reflectance control display device according to claim 59, wherein when crossed with a conceptual polarizer of the same material, the transmittance of at least one of the output polarizer and the additional polarizer for wavelengths from 520 nm to 560 nm is less than the transmittance for wavelengths from 450 nm to 490 nm.

62. The reflectance control display device according to claim 61, wherein the transmittance for wavelengths from 450 nm to 490 nm is greater than 1%; and the transmittance for wavelengths from 520 nm to 560 nm is less than 3%.

63. The reflectance control display device according to claim 44, wherein the pixel includes a light emitting diode.

64. The reflectance control display device according to claim 63, wherein the light emitting diode is an organic light emitting diode including an organic light emitting material.

65. The reflectance control display device according to claim 64, wherein the thickness of the light emitting material is different for each of the red, green, and blue light emitting regions.

66. The reflectance control display device according to claim 65, wherein for at least some of the pixels, the light emitting region includes a light emitting sub-region and a non-light emitting sub-region.

67. The reflectance control display device according to claim 66, wherein the area ratio of the light emitting sub-region to the non-light emitting region is different for red, green, and blue pixels.

68. The reflectance control display device according to claim 63, wherein at least some of the light emitting diodes are inorganic micro light emitting diodes.

69. The reflectance control display device according to claim 68, wherein the hole has an absorption rate, and at the edge of the hole, the absorption rate has a transmittance gradient, and the transmittance gradient has a transmittance gradient width greater than 1 micron.

70. The reflectance control display device according to claim 44, wherein the two-dimensional array of holes is formed on a touch sensor electrode array.

71. The reflectance control display device according to claim 44, wherein at least one absorption region of the parallax barrier includes a touch sensor electrode array.

72. The display device according to claim 44, wherein the display device does not have a polarizer arranged on the output side of the emission spatial light modulator.

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