CN117546058A - Self-luminous display panel - Google Patents

Abstract

A self-emissive display panel includes a photonic integrated circuit layer including a waveguide array and an array of couplers for coupling out portions of illumination light through pixels of the panel. The self-luminous display panel may include a transparent electronic circuit layer backlit by a photonic integrated circuit layer; the two layers may be located on the same substrate or on opposite substrates defining a cell filled with an electroactive material. This configuration allows chief ray engineering, zonal illumination, and individual illumination with red, green, and blue illumination light.

Description

Self-luminous display panel

Technical Field

The present disclosure relates to electro-optic devices, and more particularly to visual display panels and methods of making the same.

Background

Visual displays provide information to one or more viewers, including still images, video, data, and the like. Visual displays find application in a variety of fields including entertainment, education, engineering, science, professional training, advertising, to name a few. Some visual displays (e.g., televisions) display images to digital users, while some visual display systems (e.g., near-eye displays (NED)) are intended for individual users.

An artificial reality system typically includes a NED (e.g., a head set) or a pair of glasses configured to present content to a user. The near-eye display may display the virtual object, or combine an image of the real object with an image of the virtual object, as in a Virtual Reality (VR) application, an augmented reality (augmented reality, AR) application, or a Mixed Reality (MR) application. For example, in an AR system, a user may view an image (e.g., a computer-generated image (CGI)) of a virtual object superimposed with the surrounding environment through a perspective "combiner" component. The combiner of the wearable display is typically transparent to external light, but includes some light routing optics to direct the display light into the field of view of the user.

Since the Head Mounted Display (HMD) or NED display is typically worn on the head of a user, large, bulky and heavy, unbalanced and heavy display devices with heavy batteries would be cumbersome and uncomfortable for the user to wear. Accordingly, head mounted display devices may benefit from a compact and efficient construction that includes efficient light sources and illuminators, high flux collimators, and other optical elements in an image forming system that provide illumination for a display panel.

Disclosure of Invention

According to a first aspect, there is provided a self-luminous display panel including: a first substrate; a photonic integrated circuit (photonic integrated circuit, PIC) layer supported by the first substrate, the PIC layer comprising an array of waveguides for guiding illumination light; an electronic circuit layer supported by the PIC layer; and a pixelated electrode layer comprising an array of pixel electrodes, wherein the electronic circuit layer is configured to apply an electrical signal to the array of pixel electrodes; wherein the PIC layer includes an array of couplers coupled to the waveguide array for coupling out portions of the illumination light through the electronic circuit layer and through the array of pixel electrodes.

The self-luminous display panel may further include: a second substrate opposite to the first substrate; a back plate electrode layer supported by the second substrate, the pixelated electrode layer and the back plate electrode layer defining cells; and an electroactive layer located in the cell. In operation, portions of the illumination light may propagate sequentially through the electronic circuit layer, the pixel electrode, the electroactive layer, the backplate electrode, and the second substrate.

The electroactive layer may include a liquid crystal.

The array of couplers may include gratings formed in an array of waveguides.

The grating may be slanted to provide a chief ray angle of the portions of the illumination light that varies spatially from one pixel electrode to another.

The outcoupler array may comprise a nanostructure array for providing a chief ray angle of portions of illumination light spatially varying from one pixel electrode to another.

The illumination light may comprise a plurality of color channels. Each waveguide of the waveguide array may be configured to transmit each color channel of the plurality of color channels. Each of the couplers of the coupler array may be configured to couple out each of the plurality of color channels at substantially the same chief ray angle.

The waveguide array may comprise a plurality of sub-arrays. Each sub-array may be configured to carry a particular color channel of a plurality of color channels of illumination light.

According to a second aspect, there is provided a self-luminous display panel including: a first substrate and a second substrate opposite to each other; a Photonic Integrated Circuit (PIC) layer supported by the first substrate, the PIC layer comprising an array of waveguides for guiding illumination light; a back plate electrode layer supported by the PIC layer; an electronic circuit layer supported by the second substrate; a pixelated electrode layer comprising an array of pixel electrodes, wherein the electronic circuit layer is configured to apply an electrical signal to the array of pixel electrodes, the pixelated electrode layer and the backplate electrode layer defining a cell; and an electroactive layer located in the cell; wherein the PIC layer includes an array of couplers coupled to the waveguide array for coupling out portions of the illumination light through the backplate electrode layer, the electroactive layer, and the array of pixel electrodes.

The electroactive layer may include a liquid crystal.

The array of couplers may include gratings formed in an array of waveguides.

The grating may be slanted to provide a chief ray angle of the portions of the illumination light that varies spatially from one pixel electrode to another.

The outcoupler array may comprise a nanostructure array for providing a chief ray angle of portions of illumination light spatially varying from one pixel electrode to another.

The illumination light may comprise a plurality of color channels. Each waveguide of the waveguide array may be configured to transmit each color channel of the plurality of color channels. Each of the couplers of the coupler array may be configured to couple out each of the plurality of color channels at substantially the same chief ray angle.

The waveguide array may comprise a plurality of sub-arrays. Each sub-array may be configured to carry a particular color channel of a plurality of color channels of illumination light.

The waveguide array may include a plurality of sub-arrays, each sub-array coupled to a beam splitter for illuminating a particular geometric region of the pixel electrode array.

According to a third aspect, there is provided a method of manufacturing a self-luminous display panel, the method comprising: forming an electronic circuit layer on the sacrificial substrate, the electronic circuit layer comprising a pixelated electrode layer comprising an array of pixel electrodes; bonding the first substrate to the electronic circuit layer; removing the sacrificial substrate; providing a Photonic Integrated Circuit (PIC) layer comprising a waveguide array for guiding illumination light and an coupler array coupled to the waveguide array for coupling out portions of the illumination light; forming a cell by disposing a second substrate in a fixed spaced relationship with the first substrate, the second substrate supporting a back plate electrode layer, wherein the pixelated electrode layer faces the cell, and wherein, in operation, portions of the illumination light propagate through the array of pixel electrodes; and filling the cell with an electroactive material.

The PIC layer may be formed on the first substrate, and after forming the cell, the PIC layer may face the cell.

An electronic circuit layer may be disposed between the PIC layer and the electroactive material.

The PIC layer may be formed on the second substrate, and after forming the cell, the PIC layer may face the cell.

Drawings

Examples will now be described in conjunction with the accompanying drawings, in which:

fig. 1A is a side cross-sectional view of a self-luminous display panel including a photonic integrated circuit layer formed on an electronic circuit layer of a silicon substrate;

FIG. 1B is a three-dimensional partial view of the illumination waveguide and via area of the self-emissive display panel of FIG. 1A;

FIG. 2 is a side cross-sectional view of a self-emissive display panel including a photonic integrated circuit layer supported by an electronic circuit layer on a transparent substrate;

FIG. 3 is a side cross-sectional view of a self-emissive display panel including an electronic circuit layer supported by a photonic integrated circuit layer on a substrate;

FIG. 4 is a side cross-sectional view of a self-emissive display panel including a photonic integrated circuit and an electronic circuit layer on an opposing substrate;

FIG. 5 is a flow chart of a method of fabricating an electronic circuit layer on a transparent substrate and a self-emissive display based thereon;

fig. 6A and 6B are schematic diagrams of a near-eye display based on the self-luminous display panel of fig. 1A, 1B and 2 to 4 without a chief ray engineering (fig. 6A) and with a chief ray engineering (fig. 6B);

fig. 7A to 7D are side cross-sectional views of various examples of grating couplers of photonic integrated circuits of self-luminous display panels of the present disclosure;

FIG. 8A is a top view of an example of a tilted grating of a coupler of a photonic integrated circuit of a self-emissive display panel of the present disclosure;

FIG. 8B is a side cross-sectional view of a grating coupler with nanostructure-based chief ray angle control that may be used in the photonic integrated circuit of the self-luminous display panel of the present disclosure;

FIG. 8C is a top view of an example nanoantenna of the coupler of the photonic integrated circuit of the self-emissive display panel of the present disclosure;

fig. 9A to 9C are schematic views of a color illumination configuration of the self-luminous display panel of the present disclosure;

FIG. 10 is a schematic top view of a photonic integrated circuit configured for zoned illumination of a display panel of the present disclosure;

FIG. 11 is a view of a near-eye display of the present disclosure having a form factor of a pair of eyeglasses; and

fig. 12 is a three-dimensional view of a head-mounted display (HMD) of the present disclosure.

Detailed Description

While the present teachings are described in connection with various embodiments and examples, the present teachings are not intended to be limited to these embodiments. On the contrary, the present teachings encompass various alternatives and equivalents, as will be appreciated by those of skill in the art. All statements herein reciting principles, aspects, and embodiments of the disclosure, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Furthermore, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure.

As used herein, the terms "first" and "second," etc. are not intended to imply a sequential order, but rather to distinguish one element from another unless otherwise explicitly stated. Similarly, the sequential order of the method steps does not imply a sequential order of their execution unless explicitly stated. In fig. 1A, 1B, and 2 to 4, like reference numerals denote like elements.

Resolution, power consumption and form factor are important performance factors for AR displays. Micro light emitting diode (μled) displays have the advantage of high brightness, but the efficiency of such displays drops rapidly as the pixel size decreases. Furthermore, realizing a single panel full color μled display can be challenging because the red LED and the blue LED/green LED require different materials. Thus, color display applications may require the use of three separate μled projectors, which results in a tripled size and weight of the light engine. Another approach is to use a 2D scanning beam generated by a laser or superluminescent diode (SLED) to impinge on a microelectromechanical system (microelectromechanical system, MEMS) scanning reflector. However, the drivers and graphics processing controllers are quite complex and power consuming, and the overall achievable resolution may be limited by the size of the scan mirror.

Micro-display panels based on nematic liquid crystal on silicon (liquid crystal on silicon, LCoS) or ferroelectric liquid crystal on silicon (ferroelectric liquid crystal on silicon, FLCoS) provide an alternative solution for light engines that can be used for near-eye displays (e.g., virtual reality displays or augmented reality displays). With the development of new ferroelectric liquid crystal materials, pixel sizes smaller than 1.5 μm (as low as 350 nm) are possible. However, unlike emissive displays, (F) LCoS displays require additional illumination optics (e.g., polarizing beam splitters), which can increase the size and weight of the system.

(F) The latter limitation of LCoS display panels can be overcome by integrating the illumination circuitry directly onto the (F) LCoS substrate. A Photonic Integrated Circuit (PIC) layer may be provided on an integrated circuit layer of a complementary metal oxide semiconductor (complementary metal oxide semiconductor, CMOS) chip to provide a self-emissive display panel. Furthermore, PLC technology may be adapted to provide so-called chief ray engineering capabilities. PLC technology can be used to direct the chief ray of the light beam emitted by each pixel to a common collimating element, so that the overall size and/or vignetting loss (wall plug efficiency) is significantly reduced and the overall electro-optic conversion efficiency of the display device is improved. In addition, PIC technology may provide features such as zoned illumination of the display panel to achieve higher perceived contrast and power savings. Furthermore, CMOS technology can be employed to provide a substantially transparent pixel area for circuitry, thereby providing a wider variety of CMOS PLC illumination configurations, and opening the way to transparent or translucent self-luminous displays.

According to the present disclosure, there is provided a self-luminous display panel including: a first substrate; a Photonic Integrated Circuit (PIC) layer supported by the first substrate, the PIC layer comprising an array of waveguides for guiding illumination light; an electronic circuit layer supported by the PIC layer; and a pixelated electrode layer comprising an array of pixel electrodes. The electronic circuit layer is configured to apply an electrical signal to the pixel electrode array. The PIC layer includes an array of couplers coupled to the waveguide array for coupling out portions of the illumination light through the electronic circuit layer and through the array of pixel electrodes.

The self-luminous display panel may further include: a second substrate opposite to the first substrate; a back plate electrode layer supported by the second substrate, the pixelated electrode layer and the back plate electrode layer defining a cell; and an electroactive layer located in the cell. In operation, portions of the illumination light may propagate sequentially through the electronic circuit layer, the pixel electrode, the electroactive layer, the backplane electrode, and the second substrate. The electroactive layer may include a liquid crystal.

In some examples, the coupler array includes a grating formed in a waveguide array. The grating may be slanted to provide a chief ray angle of the portions of the illumination light that varies spatially from one pixel electrode to another. In some examples, the coupler array includes a nanostructure array for providing chief ray angles of portions of illumination light that spatially vary from one pixel electrode to another.

In examples where the illumination light includes a plurality of color channels, each waveguide of the waveguide array may be configured to transmit each color channel of the plurality of color channels. Each of the couplers of the coupler array may be configured to couple out each of the plurality of color channels at substantially the same chief ray angle. In some examples, the waveguide array includes a plurality of sub-arrays, and each sub-array may be configured to carry a particular color channel of a plurality of color channels of illumination light.

According to the present disclosure, there is provided a self-luminous display panel including: a first substrate and a second substrate opposite to each other; a Photonic Integrated Circuit (PIC) layer supported by the first substrate, the PIC layer comprising an array of waveguides for guiding illumination light; a back plate electrode layer supported by the PIC layer; an electronic circuit layer supported by the second substrate; a pixelated electrode layer comprising an array of pixel electrodes, wherein the electronic circuit layer is configured to apply an electrical signal to the array of pixel electrodes, the pixelated electrode layer and the backplate electrode layer defining a cell; and an electroactive layer located in the cell. The PIC layer may include an array of couplers coupled to the waveguide array for coupling out portions of the illumination light through the backplate electrode layer, the electroactive layer, and the array of pixel electrodes. The electroactive layer may include a liquid crystal.

In examples where the coupler array includes a grating formed in a waveguide array, the grating may be slanted to provide a chief ray angle of portions of illumination light that varies spatially from one pixel electrode to another. In some examples, the coupler array includes a nanostructure array for providing chief ray angles of portions of illumination light that spatially vary from one pixel electrode to another.

In examples where the illumination light includes a plurality of color channels, each waveguide of the waveguide array may be configured to transmit each color channel of the plurality of color channels. Each of the couplers of the coupler array may be configured to couple out each of the plurality of color channels at substantially the same chief ray angle.

In examples where the waveguide array includes a plurality of sub-arrays, each sub-array may be configured to carry a particular color channel of a plurality of color channels of illumination light. Each sub-array may be coupled to a beam splitter for illuminating a particular geometric area of the pixel electrode array.

According to the present disclosure, there is also provided a method of manufacturing a self-luminous display panel. The method comprises the following steps: forming an electronic circuit layer on the sacrificial substrate, the electronic circuit layer comprising a pixelated electrode layer comprising an array of pixel electrodes; bonding the first substrate to the electronic circuit layer; removing the sacrificial substrate; providing a Photonic Integrated Circuit (PIC) layer comprising a waveguide array for guiding illumination light and an coupler array coupled to the waveguide array for coupling out portions of the illumination light; forming a cell by disposing a second substrate in a fixed spaced relationship with the first substrate, the second substrate supporting a back plate electrode layer, wherein the pixelated electrode layer faces the cell, and wherein, in operation, portions of the illumination light propagate through the array of pixel electrodes; the cell is filled with an electroactive material.

The PIC layer may be formed on the first substrate, and after forming the cell, the PIC layer faces the cell. An electronic circuit layer may be disposed between the PIC layer and the electroactive material. The PIC layer may be formed on the second substrate to face the cell after forming the cell.

Referring now to fig. 1A, the self-luminous display panel 100 includes an electronic circuit layer 102, such as a CMOS circuit layer formed on a silicon substrate, supported by a first substrate 104. The electronic circuit layer 102 may include electronic gates (electronic gates) 103 for independently controlling the respective pixels of the display panel 100. The pixels of the display panel 100 are defined by a pixelated electrode layer 106 comprising an array of pixel electrodes 107.

A Photonic Integrated Circuit (PIC) layer 108 may be formed on, disposed on, and/or supported by electronic circuit layer 102. The PIC layer 108 may include an array of waveguides 109, such as single-mode waveguides or few-mode ridge waveguides running under an array of pixel electrodes 107, and configured to guide illumination light 110 emitted by an optional semiconductor light source 112 optically coupled to the waveguides 109. In this context, the term "few-mode waveguide" refers to a waveguide that supports up to 12 lateral propagation modes. The semiconductor light source 112 may be, for example, a superluminescent light emitting diode, a laser diode, or an array of such diodes. The PIC layer 108 supports the pixelated electrode layer 106.

The PIC layer 108 may include an array of couplers 111, such as grating couplers optically coupled to an array of waveguides 109, for coupling out portions 110A of the illumination 110 through an array of pixel electrodes 107 to provide self-luminous capability to the display panel 100. Herein, the term "self-illumination or self-lite" means that pixels of the display panel are internally illuminated by an internal illumination structure or an internal light guide structure, as opposed to a reflective or transmissive display panel that requires an external light source to externally irradiate light onto the panel to operate. The coupler 111 is registered with respect to the pixel electrode 107, for example, one coupler 111 may be disposed directly under one pixel electrode 107.

In the example shown in fig. 1A, the display panel 100 includes a second substrate 120 disposed opposite the first substrate 104 and a back plate electrode layer 122 supported by the second substrate 120. The pixelated electrode layer 106 and the backplate electrode layer 118 define cells 116, which are typically plane-parallel cells that are 1 to 9 microns thick. An electroactive layer 124 (e.g., a nematic liquid crystal fluid layer or a ferroelectric liquid crystal fluid layer) may fill the cells 116. The electroactive layer 124 is responsive to the electric field applied by the pixelated electrode layer 106 and the backplate electrode layer 118. Herein, the term "responsive to an electric field" refers to the electroactive layer 124 changing its properties by application of the electric field, which properties affect the optical properties (e.g., polarization state) of the portions 110A of the illumination light 110.

The second substrate 120 is transparent to the plurality of portions 110A of the illumination light 110. In the illustrated example, the PIC layer 108 is disposed between the electronic circuit layer 102 and the pixelated electrode layer 106 and electrically separates the two layers. To electrically couple the electron gate 103 with the corresponding pixel electrode 107, an array of conductive vias 114 may be provided, allowing the gate 103 of the electronic circuit layer to apply an electrical signal to the corresponding pixel electrode 107. As best seen in fig. 1B, an array of vias 114 may extend from the electronic circuit layer 102, through the PIC layer 108 between the waveguides 109 of the array, and to the array of pixel electrodes 107 at a distance large enough to not substantially interfere with the optical functions of the waveguides 109 and the couplers 111.

In operation, portions 110A of illumination light coupled out of waveguide 109 by coupler 111 propagate sequentially through pixel electrode 107, electroactive layer 124, backplane electrode layer 122, and transparent second substrate 120. The optical properties of each portion 110A (e.g., its polarization state) may be controlled in a spatially selective manner by applying a signal to the gate electrodes 103, each gate electrode 103 being electrically coupled to a respective pixel electrode 107 through a via 114 to vary the local electric field applied to a respective portion of the electroactive layer 124. Spatially varying polarization states of the coupled-out portions 110A of illumination light may be converted into an optical power density distribution (optical power density distribution) by a downstream polarizer (not shown for simplicity). The optical power density distribution of the portions 110A of the illumination light corresponds to an image displayed by the display panel 100.

Referring to fig. 2, the self-luminous display panel 200 is similar to the self-luminous display panel 100 of fig. 1 and includes similar elements. The self-luminous display panel 200 of fig. 2 includes: an electronic circuit layer 102 supported by a transparent first substrate 204, such as glass, sapphire, crystal, or the like; a PIC layer 108 located on the electronic circuit layer 102; a pixelated electrode layer 106 located on the PIC layer 108, wherein, as described above, the via 114 electrically couples the pixelated electrode layer 106 to the electronic circuit layer 102 through the PIC layer 108. The cells 116 defined by the pixelated electrode layer 106 and the backplate electrode layer 118 are filled with an electroactive layer 124. The second substrate 120 supports a backplate electrode layer 118 that includes backplate electrodes 122.

The opaque substrate material in the region 202 under the pixel electrode 107 between the electron gates 103 may be removed such that the first substrate 204 and the electronic circuit layer 102 are transparent to incident light in the region of the pixel electrode 107. The transparent substrate 204 and the transparent electronic circuit layer 102 enable the self-emissive display panel 200 to be used in various applications, such as, but not limited to, in Augmented Reality (AR) applications where image light formed by the coupled-out portions 110A of the illumination light 110 needs to be combined with external light from the surrounding environment. A method of manufacturing the electronic circuit layer 102 on the transparent substrate 204 will be further considered below.

Turning to fig. 3, a self-luminous display panel 300 is similar to the self-luminous display panel 200 of fig. 2 and includes similar elements. In the self-light emitting display panel 300 of fig. 3, the positions of the electronic circuit layer 102 and the PIC layer 108 in the layer stack supported by the first substrate 204 are exchanged, i.e., the transparent first substrate 204 supports the PIC layer 108, and the PIC layer 108 in turn supports the electronic circuit layer 102. This configuration does not require vias, as the pixelated electrode layer 106 may be directly coupled with the electronic circuit layer 102, allowing each gate 103 of the electronic circuit layer to apply an electrical signal to a corresponding pixel electrode 107. The overall structure is simplified because the via fabrication adds a number of steps to the fabrication process.

In operation, the plurality of portions 110A of illumination light coupled out of the waveguide 109 by the array of couplers 111 propagate sequentially through the electronic circuit layer 102 (specifically, through the region 202 transparent to the plurality of portions 110 of illumination light), the pixelated electrode layer 106, the electroactive layer 124, the backplate electrode layer 118, through the second substrate 120, and then out of the self-emissive display panel 300. A collimator (not shown for brevity) may receive the plurality of portions 110A of illumination light and convert an image in a linear domain displayed by the self-luminous display panel 300 into an image in an angular domain. Herein, the term "image in the angular domain" refers to such an image: in the image, the different elements of the image in the linear or spatial domain (i.e. the pixels of the image displayed by the display panel) are represented by angles of corresponding rays of image light that carry optical power levels and/or colors corresponding to the brightness and/or color values of the pixels of the image.

Referring now to fig. 4, a self-luminous display panel 400 is similar to the self-luminous display panel 300 of fig. 3 and includes similar elements. In the self-luminous display panel 400 of fig. 4, the electronic circuit layer 102 is moved to another substrate; in other words, the first substrate 204 supports the PIC layer 108 that supports the backplate electrode layer 118, while the second substrate 120 supports the electronic circuit layer 102 that supports the pixelated electrode layer 106 (shown inverted in fig. 4). The pixelated electrode layer 106 and the backplate electrode layer 118 define a cell 116, wherein an electroactive layer 124 is disposed in the cell 116, as in the previous examples.

In operation, portions 110A of illumination light coupled out of waveguide 109 by the plurality of couplers 111 propagate sequentially through backplate electrode 122, electroactive layer 124, pixel electrode 107, electronic circuit layer 102 (more specifically, through transparent region 202), and transparent second substrate 120, and further to collimation/imaging optics (not shown).

Turning to fig. 5, a method 500 of manufacturing a self-luminous display panel of the present disclosure includes: an electronic circuit layer is formed (502) on a sacrificial substrate, for example, a CMOS electronic circuit layer is formed on a silicon substrate. The electronic circuit layers may include pixel control gates, connections, vias, pixelated electrode layers including arrays of pixel electrodes, etc., as desired for the intended display operation. The formed electronic circuit layer is bonded (504) from an opposite side of the electronic circuit layer to a first substrate, such as a glass or sapphire transparent substrate. The sacrificial substrate is then removed 506 by, for example, etching.

Opaque material from under the pixelated electrodes may be removed 508 and the resulting structure may be backfilled or planarized 510 to form transparent regions, such as the region 202 under the pixel electrodes of the self-emissive display panel 200 of fig. 2, the self-emissive display panel 300 of fig. 3, or the self-emissive display panel 400 of fig. 4. The PIC layer may then be set 512. The PIC layer may be disposed on a planarized electronic circuit layer ("EC layer" in fig. 5), for example, as in the self-luminous display panel 300 in fig. 3. The electronic circuit layer may be disposed on another substrate of the cell, for example as in self-luminous display panel 400 of fig. 4. The formed PIC layer may include a waveguide array for guiding illumination light and an outcoupler array coupled to the waveguide array for outcoupling portions of the illumination light, as explained above with reference to fig. 1-4. The cell may then be formed (514) by providing a second substrate in a fixed spaced relationship to the first substrate, the second substrate supporting the backplate electrode layer. The cell is defined by electrodes facing the cell as in the display panels of fig. 1 to 4. The cell may then be filled 516 with an electroactive material, such as a nematic or ferroelectric LC fluid.

In some examples, such as in the self-light emitting display panel 200 of fig. 2, and in the self-light emitting display panel 300 of fig. 3, the PIC layer is formed on the first substrate so as to face the cell after the cell is formed. In such an example, the electronic circuit layer may be disposed between the PIC layer and the electroactive material. In some examples, after forming a cell, the PIC layer may be formed on a second substrate facing the cell, for example as in self-emissive display panel 400 of fig. 4.

The self-luminescence properties provided by the PIC structure with the waveguide array and the coupler array enable the chief rays of the respective coupled-out illumination light portions to be guided to a predetermined position, for example to the position of a collimating element such as a collimator lens, so-called chief ray engineering. As used herein, the term "chief ray" refers to a ray that carries a majority of emitted light energy as compared to other rays in a ray fan representing a beam of light. It should be noted that the term "chief ray" as defined herein does not necessarily propagate through the center of the optical system.

Referring to the non-limiting illustrative example of fig. 6A, a display device 650A, shown in partial view, includes a self-emissive display panel 600A optically coupled to a collimator 630. The self-light emitting display panel 600A includes a pixel array defined by respective pixel electrodes as described above with reference to the self-light emitting display 100 of fig. 1A, the self-light emitting display 200 of fig. 2, the self-light emitting display 300 of fig. 3, and the self-light emitting display 400 of fig. 4. Each pixel emits a cone of light that is to be collimated into a collimated beam by a common collimator 630. The collimator 630 is disposed at a position one focal distance from the self-luminous display panel 600A. In other words, the self-luminous display panel 600A is disposed in the focal plane 632 of the collimator 630. The angle of the collimated beam relative to the X-axis depends on the X-coordinate of the emission pixel. For example, pixel 601A of self-emitting display panel 600A emits a cone or diverging beam 602A of light that is collimated by collimator 630 into a collimated beam 604A at an angle β to the X-axis.

Each pixel of the self-luminous display panel 600A emits light cones whose principal rays are perpendicular to the plane or XY plane of the self-luminous display panel 600A, i.e., the angle α between the principal rays and the XY plane is equal to 90 degrees. In other words, most of the light energy emitted by the pixel propagates along the Z-axis, as indicated by dashed line 606. It can be seen that the external light rays (two external light rays on each side of the collimator 630) are truncated (clip) and do not propagate through the collimator 630, because in this example, the collimator 630 is smaller than the self-luminous display panel 600A. This will cause the image displayed by the self-luminous display panel 600A to vignetting.

Turning now to fig. 6B, a display device 650B includes a self-emissive display panel 600B optically coupled to a collimator 630. The self-light emitting display panel 600B includes a pixel array defined by respective pixel electrodes as described above with reference to the self-light emitting display 100 of fig. 1A, the self-light emitting display 200 of fig. 2, the self-light emitting display 300 of fig. 3, and the self-light emitting display 400 of fig. 4. Each pixel emits a cone of light to be collimated by a common collimator 630 disposed at a focal distance from the self-luminous display panel 600B. The angle of the collimated beam relative to the X-axis depends on the X-coordinate of the pixel. For example, pixel 601B of self-emitting display panel 600B emits a cone or diverging beam 602B of light that is collimated by collimator 630 into a collimated beam 604B at an angle β to the X-axis. The chief ray angle of divergent light beams emitted from different pixels of the self-luminous display panel 600B depends on the X-coordinate to guide the chief rays to the collimator 630. For example, the diverging beam 602B is tilted rather than straight as shown in fig. 6A. This makes it possible to avoid or significantly reduce vignetting of an image displayed by the self-light emitting display panel 600B. It should also be noted that in the first approximation, the angle β of the collimated beam 604B is not affected by the angle α of inclination of the chief ray, since this angle β depends only on the pixel coordinates. The desired guiding of the chief rays of the light beams emitted by the pixels of the self-luminous display panel 600B may be achieved by configuring an array of couplers 111 (fig. 1A, 2, 3 and 4) coupled to the array of waveguides 109 for coupling out portions 110A of the illumination light 110 through the array of pixel electrodes 107 at chief ray angles spatially varying from one pixel electrode 107 to another, e.g. passing all rays through a collimator. It is further noted that the outcoupler 111 may also be configured to control the cone angle of the diverging beam 602B of the outcoupled portions of illumination light, i.e. the angular width of the emitted light cone 602B.

A non-limiting example of the coupler 111 for any of the self-luminous display panels of the present disclosure will now be described. These configurations may be used for chief ray engineering and may be optimized for uniform illumination, exit pupil control, etc. Referring first to fig. 7A, the coupler 711A includes a grating structure 702A etched into the core 704 of the ridge waveguide of the PIC layer. The period or pitch (pitch) of the grating structures 702A may be selected to couple out portions of the illumination light toward the electroactive layer at a desired coupling-out angle. The etch depth of grating structure 702A may be spatially varied to provide spatially varying outcoupling efficiency.

In fig. 7B, the coupler 711B includes a grating structure 702B supported by a spacer layer 706 supported by the core 704 of the ridge waveguide. The period or pitch of the grating structures 702B may be selected to couple out portions of the illumination light toward the electroactive layer at a desired coupling-out angle. The thickness of the spacer layer 706 may be spatially varied to provide spatially varying outcoupling efficiency.

Referring now to fig. 7C, the coupler 711C is similar to the coupler 711A of fig. 7A. The coupler 711C of fig. 7C includes a slanted grating structure 702C that is etched into the core 704 of the ridge waveguide of the PIC layer. The tilting of the grating structure 702C enables the amount of light energy entering a selected diffraction order to be changed (increased or decreased).

Turning to fig. 7D, the coupler 711D is similar to the coupler 711C of fig. 7C. The coupler 711D of fig. 7D includes a binary slanted grating structure 702D etched into the core 704 of the ridge waveguide of the PIC layer. Binary tilted grating structure 702D may be obtained by a series of straight etching steps. In fig. 7A-7D, grating structures 702A-702D may be disposed on top and/or bottom of respective ridge waveguides. The pitch of the grating structures 702A-702D may be chirped to control the cone angle, i.e., the angular spread of the portions of the out-coupled illumination light.

Referring now to fig. 8A, the coupler 811A is similar to the coupler 711A of fig. 7A and includes similar elements. The grating structure 802A etched in the core 804 of the ridge waveguide of the PIC layer is tilted in the plane of the PIC layer (i.e., in the XY plane) to redirect the chief rays of the corresponding out-coupled illumination light portion in a direction perpendicular to the core 804, e.g., toward a collimator, to reduce vignetting and improve light utilization efficiency, as explained above with reference to fig. 6A and 6B. More generally, the etched grating structure may be tilted in two planes, namely in the plane perpendicular to the plane of the PIC layer (XY plane) (XZ plane) of fig. 7C and in the plane of fig. 8A (XY plane), to redirect the chief ray in two orthogonal directions. Etched grating structure 802A may also be chirped for taper angle control.

Referring to fig. 8B, the coupler 811B includes: a grating 802B etched into the ridge waveguide 804; an optional spacer layer 806 supported by the grating 802B; and an array of nanostructures 808 supported by the spacer layer 806. The array of nanostructures 808 may be configured to provide a desired chief ray angle, cone width, etc.

Turning to fig. 8C, the coupler 811C includes a nanoantenna 802C that is shaped and sized to provide the desired angular cone width and chief ray angle of the portion of illumination light coupled out of the core 804 of the ridge waveguide. The length L and width W of the nanoantenna 802C, as well as the material of the nanoantenna 802B, may be selected to provide desired out-coupling strength and angular characteristics, for example, due to the electromagnetic resonance of the nanoantenna 802C defined by its geometry and material. The nanoantenna 802B may be dielectric or metallic (plasmonic). The length L and width W are typically less than 1 micron. A nanoantenna 802C array may be provided, wherein a row of the array is coupled to each ridge waveguide. Furthermore, in all examples of the outcouplers of fig. 7A to 7D and 8A to 8C, the relevant parameters of the outcouplers may be spatially varied to provide spatially varying chief ray angles, as explained above with reference to fig. 6A and 6B.

An exemplary color illumination configuration of the PIC layer in the self-luminous display panel of the present disclosure will now be described. Fig. 9A is a top view of the PIC layer 908A, which is a variation of the PIC layer 108 of any one of the self-light emitting display panel 100 of fig. 1A, the self-light emitting display panel 200 of fig. 2, the self-light emitting display panel 300 of fig. 3, and the self-light emitting display panel 400 of fig. 4. The PIC layer 908A of fig. 9A includes an array of waveguides 905A that includes a plurality of sub-arrays, each configured to carry a particular color channel of a plurality of color channels of illumination light. Specifically, in this example, the waveguide 905A array includes a red waveguide sub-array 904R for transmitting illumination light of a red channel, a green waveguide sub-array 904G for transmitting illumination light of a green channel, and a blue waveguide sub-array 904B for transmitting illumination light of a blue channel. The red, green, and blue sub-arrays 904R, 904G, 904B are staggered and extend parallel to each other in a common plane (i.e., XY plane), as shown in fig. 9A. The waveguides of the red waveguide sub-array 904R include a plurality of grating couplers 902R for coupling out portions of the illumination light; the waveguides of the green waveguide sub-array 904G include a plurality of grating couplers 902G for coupling out portions of the green illumination light; and the waveguides of the blue waveguide sub-array 904B include a plurality of grating couplers 902B for coupling out portions of the blue illumination light.

Referring to fig. 9B, the PIC layer 908B is a variation of the PIC layer 108 of any one of the self-light emitting display panel 100 of fig. 1A, the self-light emitting display panel 200 of fig. 2, the self-light emitting display panel 300 of fig. 3, and the self-light emitting display panel 400 of fig. 4. The PIC layer 908B of fig. 9B includes an array of waveguides 905B having a plurality of sub-arrays, each configured to carry a particular color channel of a plurality of color channels of illumination light. Specifically, in this example, the waveguide 905B array includes a red waveguide sub-array 904R for transmitting illumination light of a red channel, a green waveguide sub-array 904G for transmitting illumination light of a green channel, and a blue waveguide sub-array 904B for transmitting illumination light of a blue channel. As shown, the waveguides of red sub-array 904R, the waveguides of green sub-array 904G, and the waveguides of blue sub-array 904B extend one below the other at different z-depths in PIC layer 908B. The waveguides of the sub-array 904R include a plurality of grating couplers 902R for coupling out portions of the red illumination light 910R, the waveguides of the green sub-array 904G include a plurality of grating couplers 902G for coupling out portions of the green illumination light 910G, and the waveguides of the blue sub-array 904B include a plurality of grating couplers 902B for coupling out portions of the blue illumination light 910B. As shown, the grating couplers 902R, 902G, and 902B that illuminate the same pixel are disposed one below the other.

Turning to fig. 9C, the PIC layer 908C is a variation of the PIC layer 108 of any one of the self-luminous display panel 100 of fig. 1A, the self-luminous display panel 200 of fig. 2, the self-luminous display panel 300 of fig. 3, and the self-luminous display panel 400 of fig. 4. The PIC layer 908C of fig. 9C includes an array of waveguides 905C, each waveguide 905C including an array of color non-selective couplers 902. Each color non-selective coupler 902 is configured to couple out each of a plurality of color channels (i.e., red illumination light 910R, green illumination light 910G, and blue illumination light 910B) at substantially the same chief ray angle. An example of a color non-selective coupler is given in U.S. patent No. 10,877,214B2 to Shipton et al, which is incorporated herein by reference in its entirety.

Referring to fig. 10, the PIC layer 1008 is a variation of the PIC layer 108 of any one of the self-light emitting display panel 100 of fig. 1A, the self-light emitting display panel 200 of fig. 2, the self-light emitting display panel 300 of fig. 3, and the self-light emitting display panel 400 of fig. 4. The PIC layer 1008 of fig. 10 includes a waveguide array that includes a plurality of sub-arrays 1004-1, 1004-2, …, 1004-N, each coupled to a beam splitter 1009-1, 1009-2, …, 1009-N for illuminating a particular geometric area of the array of pixel electrodes 1007. Each sub-array may include a red waveguide, a green waveguide, and a blue waveguide (i.e., waveguides configured to guide red (R), green (G), and blue (B) illumination light) for guiding light of the respective color channels. Such a configuration provides the possibility of a divisional illumination for the self-luminous display panel, i.e. the possibility of reducing or even cutting off the illumination light under dark areas of the image being displayed, thereby achieving overall energy saving for images where only a part of the image is bright and improving the overall perceived image contrast.

In some examples, each zone is illuminated by a dedicated laser source or a set of laser sources, or more generally semiconductor light sources, as shown in fig. 10. In some examples, a single light source per color channel may be used, such as a light source for the R color channel, a light source for the G color channel, and a light source for the B color channel. The light sources of each of R, G and B color channels may be coupled to one or more dedicated on-chip active PIC elements (e.g., optical switches or variable splitters) that redistribute light energy among different regions according to image content.

Referring to fig. 11, a Virtual Reality (VR) near-eye display 1100 includes a frame 1101 that supports for each eye: a self-light emitting display panel 1110 (e.g., any of the self-light emitting display panels disclosed herein); and an eyepiece or collimator 1120 for converting an image in the linear domain produced by display panel 1110 into an image in the angular domain for direct viewing at eyebox 1112. A plurality of eyebox illuminators 1106, shown as black dots, may be placed around display panel 1110 on the surface facing eyebox 1112. An eye tracking camera 1104 may be provided for each eyebox 1112.

The purpose of the eye-tracking camera 1104 is to determine the position and/or orientation of the user's eyes. The eyebox illuminator 1106 illuminates the eye at the corresponding eyebox 1112, allowing the eye tracking camera 1104 to obtain an image of the eye and provide a reference reflection, i.e., glint. Flicker may be used as a reference point in the acquired eye image to facilitate the determination of the eye gaze direction by determining the position of the eye pupil image relative to the flicker image. To avoid distracting the user's light from the eyebox illuminator 1106, the eyebox illuminator may be caused to emit light that is not visible to the user. For example, infrared light may be used to illuminate the eyebox 1112.

Turning to fig. 12, hmd 1200 is an example of an AR/VR wearable display system that encloses a user's face in order to more immerse it in an AR/VR environment. HMD 1200 may generate a fully virtual 3D image. HMD 1200 may include a front body 1202 and a belt 1204 that may be secured around a user's head. The front body 1202 is configured for placement in front of the user's eyes in a reliable and comfortable manner. A display system 1280 may be disposed in the front body 1202 for presenting AR/VR images to a user. The display system 1280 may include any of the self-emissive display panels disclosed herein. The side 1206 of the front body 1202 may be opaque or transparent.

In some examples, the front body 1202 includes a locator 1208 and an inertial measurement unit (inertial measurement unit, IMU) 1210 for tracking acceleration of the HMD 1200, and a position sensor 1212 for tracking a position of the HMD 1200. The IMU 2100 is an electronic device that generates data representing a position of the HMD 1200 based on received measurement signals from one or more of the plurality of sensors 2112 that generate one or more measurement signals in response to movement of the HMD 1200. Examples of the position sensor 1212 include: one or more accelerometers, one or more gyroscopes, one or more magnetometers, other suitable types of sensors that detect motion, a type of sensor for error correction of IMU 1210, or some combination thereof. The position sensor 1212 may be located external to the IMU 1210, internal to the IMU 1210, or some combination thereof.

The localizer 1208 is tracked by an external imaging device of the virtual reality system so that the virtual reality system can track the position and orientation of the entire HMD 1200. The information generated by the IMU 1210 and the position sensor 1212 may be compared to the position and orientation acquired by the tracking locator 1208 to improve the tracking accuracy of the position and orientation of the HMD 1200. As a user moves and rotates in 3D space, the exact position and orientation is important for presenting the user with the proper virtual scene.

The HMD 1200 may also include a depth camera assembly (depth camera assembly, DCA) 1211 that collects data describing depth information of a partial region surrounding part or all of the HMD 1200. The depth information may be compared to information from IMU 1210 in order to more accurately determine the position and orientation of HMD 1200 in 3D space.

The HMD 1200 may also include an eye tracking system 1214 for determining the orientation and position of a user's eyes in real-time. The acquired position and orientation of the eyes also allows the HMD 1200 to determine the gaze direction of the user and adjust the image generated by the display system 1280 accordingly. The determined gaze direction and vergence angle may be used to adjust the display system 1280 to reduce vergence adjustment conflicts. As disclosed herein, the direction and vergence may also be used for exit pupil steering of the display. Further, the determined vergence and gaze angle may be used to interact with a user, highlight an object, bring an object to the foreground, create additional objects or pointers, and so forth. An audio system may also be provided that includes, for example, a set of small speakers built into the front body 1202.

Embodiments of the present disclosure may include or be implemented in conjunction with an artificial reality system. The artificial reality system adjusts sensory information (e.g., visual information, audio, touch (somatosensory) information, acceleration, balance, etc.) about the outside world obtained through the sense of sense in some way, and then presents to the user. As non-limiting examples, the artificial reality may include Virtual Reality (VR), augmented Reality (AR), mixed Reality (MR), mixed reality (hybrid reality), or some combination and/or derivative thereof. The artificial reality content may include entirely generated content, or generated content in combination with captured (e.g., real world) content. The artificial reality content may include video, audio, physical or tactile feedback, or some combination thereof. Any of these content may be presented in a single channel or in multiple channels (e.g., in stereoscopic video that produces a three-dimensional effect to the viewer). Further, in some embodiments, the artificial reality may also be associated with applications, products, accessories, services, or some combination thereof, for creating content in the artificial reality and/or otherwise for use in the artificial reality (e.g., performing an activity in the artificial reality), for example. The artificial reality system providing artificial reality content may be implemented on a variety of platforms including a wearable display (e.g., an HMD connected to a host computer system), a stand-alone HMD, a near-eye display with a form factor of glasses, a mobile device or computing system, or any other hardware platform capable of providing artificial reality content to one or more viewers.

The scope of the present disclosure is not limited by the specific embodiments described herein. Indeed, various other embodiments and modifications in addition to those described herein will be apparent to those skilled in the art from the foregoing description and accompanying drawings. Accordingly, such other embodiments and modifications are intended to fall within the scope of this disclosure. Furthermore, although the present disclosure has been described herein in the context of a particular implementation in a particular environment for a particular purpose, those of ordinary skill in the art will recognize that its usefulness is not limited thereto and that the present disclosure may be beneficially implemented in any number of environments for any number of purposes. Accordingly, the appended claims should be construed in light of the full breadth of the disclosure as described herein.

Claims (15)

1. A self-luminous display panel, the self-luminous display panel comprising:

a first substrate;

a Photonic Integrated Circuit (PIC) layer supported by the first substrate, the PIC layer comprising an array of waveguides for guiding illumination light;

an electronic circuit layer supported by the PIC layer; and

a pixelated electrode layer comprising an array of pixel electrodes, wherein the electronic circuit layer is configured to apply an electrical signal to the array of pixel electrodes;

Wherein the PIC layer includes an array of couplers coupled to the waveguide array for coupling out portions of the illumination light through the electronic circuit layer and through the array of pixel electrodes.

2. The self-luminous display panel according to claim 1, further comprising:

a second substrate opposite to the first substrate;

a back plate electrode layer supported by the second substrate, the pixelated electrode layer and the back plate electrode layer defining a cell; and

an electroactive layer located in the cell;

wherein, in operation, portions of the illumination light propagate sequentially through the electronic circuit layer, the pixel electrode, the electroactive layer, the backplate electrode, and the second substrate;

preferably, wherein the electroactive layer comprises liquid crystal.

3. The self-luminous display panel according to claim 1 or 2, wherein the coupler array comprises a grating formed in the waveguide array;

preferably, wherein the grating is slanted to provide a chief ray angle of the plurality of portions of the illumination light that varies spatially from one pixel electrode to another pixel electrode.

4. A self light emitting display panel according to any preceding claim, wherein the coupler array comprises a nanostructure array for providing a chief ray angle of the plurality of portions of the illumination light that varies spatially from one pixel electrode to another.

5. A self light emitting display panel according to any preceding claim, wherein,

the illumination light includes a plurality of color channels;

each waveguide of the waveguide array is configured to transmit each color channel of the plurality of color channels; and is also provided with

Each coupler of the array of couplers is configured to couple out each color channel of the plurality of color channels at substantially the same chief ray angle.

6. A self light emitting display panel according to any preceding claim, wherein the waveguide array comprises a plurality of sub-arrays, wherein each sub-array is configured to carry a particular color channel of the plurality of color channels of the illumination light.

7. A self-luminous display panel, the self-luminous display panel comprising:

a first substrate and a second substrate opposite to each other;

a Photonic Integrated Circuit (PIC) layer supported by the first substrate, the PIC layer comprising an array of waveguides for guiding illumination light;

A backplate electrode layer supported by the PIC layer;

an electronic circuit layer supported by the second substrate;

a pixelated electrode layer comprising an array of pixel electrodes, wherein the electronic circuit layer is configured to apply an electrical signal to the array of pixel electrodes, the pixelated electrode layer and the backplate electrode layer defining a cell; and

an electroactive layer located in the cell;

wherein the PIC layer includes an array of couplers coupled to the waveguide array for coupling out portions of the illumination light through the backplate electrode layer, the electroactive layer, and the array of pixel electrodes.

8. The self-luminous display panel of claim 7, wherein the electroactive layer comprises liquid crystal.

9. The self-luminous display panel according to claim 7 or 8, wherein the coupler array comprises a grating formed in the waveguide array;

preferably, wherein the grating is slanted to provide a chief ray angle of the plurality of portions of the illumination light that varies spatially from one pixel electrode to another pixel electrode.

10. The self-luminous display panel of any one of claims 7 to 9, wherein the coupler array comprises a nanostructure array for providing a chief ray angle of the plurality of portions of the illumination light that varies spatially from one pixel electrode to another pixel electrode.

11. The self-luminous display panel according to any one of claims 7 to 10, wherein,

the illumination light includes a plurality of color channels;

each waveguide of the waveguide array is configured to transmit each color channel of the plurality of color channels; and is also provided with

Each coupler of the array of couplers is configured to couple out each color channel of the plurality of color channels at substantially the same chief ray angle.

12. The self-luminous display panel of any one of claims 7 to 11, wherein the waveguide array comprises a plurality of sub-arrays, wherein each sub-array is configured to carry a particular color channel of the plurality of color channels of the illumination light;

preferably, wherein each sub-array is coupled to a beam splitter for illuminating a specific geometrical area of the pixel electrode array.

13. A method of manufacturing a self-luminous display panel, the method comprising:

Forming an electronic circuit layer on a sacrificial substrate, the electronic circuit layer comprising a pixelated electrode layer comprising an array of pixel electrodes;

bonding a first substrate to the electronic circuit layer;

removing the sacrificial substrate;

providing a Photonic Integrated Circuit (PIC) layer comprising a waveguide array for guiding illumination light and an outcoupler array coupled to the waveguide array for outcoupling portions of the illumination light;

forming a cell by disposing a second substrate in a fixed spaced relationship with the first substrate, the second substrate supporting a backplane electrode layer, wherein the pixelated electrode layer faces the cell, and wherein, in operation, portions of the illumination light propagate through the array of pixel electrodes; and

the cell is filled with an electroactive material.

14. The method of claim 13, wherein the PIC layer is formed on the first substrate and faces the cell when the cell is formed;

preferably, wherein the electronic circuit layer is disposed between the PIC layer and the electroactive material.

15. The method of claim 13 or 14, wherein the PIC layer is formed on the second substrate and faces the cell when the cell is formed.