Optical display system and electronic device

Abstract

An optical display system (100) and an electronic device (600) are disclosed. The optical display system (100) comprises: an image generating unit (101) generating an image light output, wherein the image light output has a narrow angular luminance distribution (321, 322); and an optical lens system (104) placed in front of the image generating unit (101) and directing the image light output to an eye (106) of a viewer, wherein the image generating unit (101) comprises: an image generating component (102) generating a polarized light output; a polarization-dependent light deflecting component (103) arranged for accepting the polarized light output from the image generating component (102) and increasing an amount of the polarized light output that can enter an exit pupil (105) of the optical lens system (104), and the polarized light output deflected by the polarization-dependent light deflecting component (103) has the narrow angular luminance distribution (321, 322).

Description

[0001] Federally funded research

[0002] This invention was completed with funding from Project 6501-8684 of Goertek Inc. Goertek Inc. holds certain rights to this invention. Technical Field

[0003] Embodiments of this disclosure relate to the field of optical systems, and more particularly to optical display systems and electronic devices. Background Technology

[0004] Electronic devices typically include one or more displays. For example, mobile phones, smartwatches, and laptops often include direct-view displays for presenting information to the user. Virtual reality and / or augmented reality devices often include two sets of displays located in front of the user's eyes.

[0005] Displays, such as virtual reality and / or augmented reality displays, consist of a display panel and display optics. The display optics project or magnify the image displayed on the panel. Creating an ideal display panel that matches the display optics can be challenging. Sometimes, a large amount of light from the display panel may not reach the display optics, instead becoming stray light that hinders the performance of the display system. Summary of the Invention

[0006] One objective of this disclosure is to provide a new technical solution for an optical display system.

[0007] According to a first aspect of this disclosure, an optical display system is provided, comprising: an image generating unit and an optical lens system. The image generating unit generates an image light output, wherein the image light output has a narrow-angle brightness distribution. The optical lens system is positioned in front of the image generating unit and guides the image light output to the viewer's eye. The image generating unit includes: an image generating component that generates polarized light output; and a polarization-dependent light deflection component configured to receive the polarized light output from the image generating component and increase the amount of polarized light output that can enter the exit pupil of the optical lens system, wherein the polarized light output deflected by the polarization-dependent light deflection component has a narrow-angle brightness distribution.

[0008] According to a first aspect of this disclosure, an electronic device is provided that includes an optical display system according to an embodiment of this disclosure.

[0009] In various embodiments, the performance of the optical display system can be improved.

[0010] Further features and advantages of this disclosure will become apparent from the following detailed description of exemplary embodiments according to the accompanying drawings. Attached Figure Description

[0011] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the present disclosure and, together with their description, serve to explain the principles of the present disclosure.

[0012] Figure 1 A schematic diagram illustrating an optical display system according to an embodiment of the present disclosure.

[0013] Figure 2 This represents a cross-sectional view of a traditional display system.

[0014] Figure 3 This is a cross-sectional view of an example display system according to an embodiment of the present disclosure.

[0015] Figure 4 This indicates the liquid crystal orientation in an example light deflection layer according to an embodiment of the present disclosure.

[0016] Figure 5 This indicates the liquid crystal orientation on top of an example pixel according to an embodiment of this disclosure.

[0017] Figure 6 This refers to an electronic device according to an embodiment of the present disclosure. Detailed Implementation

[0018] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments are not intended to limit the scope of the invention.

[0019] The following description of at least one exemplary embodiment is merely illustrative in nature and is by no means intended to limit the invention, its application, or its use.

[0020] Techniques, methods, and equipment known to those skilled in the art will not be discussed in detail, but are intended to be part of the instruction manual where appropriate.

[0021] In all examples shown and discussed herein, any particular value should be interpreted as illustrative rather than limiting. Therefore, other examples of exemplary embodiments may have different values.

[0022] Please note that similar reference numerals and letters refer to similar items in the following diagram, so once an item is defined in a diagram, it may not need to be discussed further in the following diagram.

[0023] Please note that similar reference numerals and letters in the following figures refer to similar items, so once an item is defined in a figure, it may not need to be discussed further in subsequent figures.

[0024] Near-eye display technology can be used in virtual reality and / or augmented reality devices. Such devices are widely used in engineering, design, training, entertainment, retail, and other fields. Typically, a near-eye display module includes a display panel (image generation unit) for each eye and a lens system (image projection unit). Several options are available for the display panel, including but not limited to liquid crystal displays, organic light-emitting diode displays, and micro-light-emitting diode displays.

[0025] In a normal display system, the light emitted by the display panel has a relatively wide angular brightness distribution so that multiple viewers at different positions and viewing angles can clearly see the displayed image. However, this is not suitable for virtual reality and augmented reality devices. For example, most virtual reality and augmented reality devices have only one viewer, and the relative position between the viewer (user) and the near-eye display is fixed. Therefore, a large amount of light emitted by the display panel cannot be received by the viewer's pupil, resulting in significant energy loss. Furthermore, light not intended for use in the optical design may reflect back and forth between the lens system and the display panel, leading to significant background noise and thus reducing the contrast of the near-eye display module.

[0026] In addition, other problems may exist in near-eye display systems that use wide-view display panels, such as intensity vignetting and color shift in the field of view.

[0027] For example, Figure 2 This is a cross-sectional view of a conventional display system 200. The conventional display system 200 may include a wide-viewing-angle display panel 201 and a lens group 204. The central field principal ray 211 of the lens group 204 is perpendicular to the wide-viewing-angle display panel 201. The edge field principal rays 212 of the lens group 204 are not perpendicular to the wide-viewing-angle display panel 201. The wide-viewing-angle display panel 201 has a wide-angle brightness distribution 221 across its entire surface. Only a portion of the light, such as ray 231, can enter the eye 106. Most of the light outside the emission cone, such as ray 232, becomes stray light and reduces the contrast of the conventional display system 200.

[0028] In addition, such as Figure 2As shown, the angular brightness distribution 221 of the display panel 201 is relatively wide, and the main ray (e.g., main ray 212) may not be the ray with the highest brightness; the ray with the highest brightness is the ray perpendicular to the display panel 201. This may result in greater brightness non-uniformity for the viewer. Furthermore, this may lead to a loss of brightness efficiency for the display panel. Additionally, the optical display system of virtual reality and augmented reality display devices can be housed within a closed enclosure. In this case, light other than the main ray may propagate back and forth within the virtual reality and augmented reality display device, becoming stray light and affecting the viewer's viewing experience.

[0029] This paper presents an optical display system in which a customized angular brightness distribution is generated for the optical lens system. This optical display system can improve light efficiency and reduce vignetting for viewers at designed locations.

[0030] Figure 1 This is a schematic diagram illustrating an optical display system 100 according to an embodiment of the present disclosure. (See attached diagram.) Figure 1 As shown, the optical display system 100 may include an image generation unit or display panel assembly 101 and an optical lens system 104. The image light output generated by the image generation unit 101 will penetrate the optical lens system 104 to reach the exit pupil 105 and enter the viewer's eye 106.

[0031] Image light output exhibits a narrow angular brightness distribution. This means that the angular brightness distribution is relatively narrow compared to ordinary display panels such as liquid crystal displays, organic light-emitting diode displays, and micro-light-emitting diode displays. For example, the full-width at half maximum (FWHM) of the narrow angular brightness distribution of polarized light output is less than 30 degrees, 25 degrees, 20 degrees, 15 degrees, or 10 degrees. This can be achieved by applying optical components to the display panel.

[0032] An optical lens system 104 is positioned in front of the image generation unit 101 and directs the image light output to the viewer's eye 106. The optical lens system 104 amplifies the output of the image generation unit. In some embodiments, the optical lens system 104 may include reflective and refractive optical surfaces. The optical lens system 104 is configured to direct the light output from the image generation unit 101 to the eyebox located at the exit pupil 105, and then to the viewer's eye 106. For example, the optical lens system 104 includes a singlet lens. For example, the optical lens system 104 is or is a near-telecentric optical system, where the principal ray is approximately parallel to the optical axis.

[0033] The image generation unit 101 includes an image generation component 102 and a polarization-dependent light deflection component.

[0034] The image generation unit 102 generates polarized light output. The polarized light output can be circularly polarized light output. The image generation unit 102 may include a linearly polarized directional display device with a quarter-wave plate, or a non-polarized directional display device with a circular polarizer.

[0035] For example, the image generation component 102 includes a display panel, such as a liquid crystal display or a light-emitting diode display, having a pixel array. The display panel is a liquid crystal display.

[0036] For example, the image generation unit 102 is a liquid crystal display with a directional backlight unit that enhances brightness in the vertical direction.

[0037] For example, the image generation component 102 is an organic light-emitting diode (OLED) display with a cavity structure that enhances brightness in the vertical direction. The OLED display can use a silicon backplane.

[0038] For example, the image generation unit 102 is an inorganic light-emitting diode (LED) display. The inorganic LED display has a cavity structure that enhances brightness in the vertical direction. The LED display may have a nanowire structure. The display panel may have a narrow angular brightness distribution.

[0039] For example, the image generation component 102 can be a polychromatic display with directional backlighting.

[0040] The polarization-dependent light deflection component 103 is configured to receive polarized light output from the image generation component 102 and increase the amount of polarized light output that can enter the exit pupil 105 of the optical lens system 104. The polarization-dependent light deflection component 103 may be disposed on top of the image generation component 102. The polarized light output deflected by the polarization-dependent light deflection component 103 has a narrow angular brightness distribution. In this regard, the polarization-dependent light deflection component 103 can be any suitable planar optical element capable of adjusting the angular brightness distribution of the light emitted by the image generation component 102 to improve light efficiency and reduce vignetting. In some embodiments, the light deflection layer may be attached to the top surface of the display panel. In some embodiments, the polarization-dependent light deflection component 103 may be directly integrated into the image generation component 102 as a microstructure on each pixel.

[0041] The polarization-dependent light deflection component 103 can be attached to the surface of the image generation component 102. The polarization-dependent light deflection component 103 can change the angular brightness distribution of the image generation component 102.

[0042] In this example, the polarization-dependent light deflection component 103 can be a diffractive liquid crystal waveplate. The diffractive liquid crystal waveplate can change the angular brightness distribution of the pixels in the image generation component 102.

[0043] Figure 3 This indicates the optical path of the optical display system 300 according to an embodiment of the present disclosure.

[0044] like Figure 3 As shown, the image generation unit 102 generates polarized light output. The polarization-dependent light deflection unit 103 is configured to receive the polarized light output from the image generation unit 102. The polarization-dependent light deflection unit 103 deflects the light output toward the local principal ray direction of the optical lens system 204, thereby increasing the amount of polarized light output that can enter the viewer's eye 106.

[0045] exist Figure 3 In this context, the principal ray 212 is represented as having the highest brightness. However, in some embodiments, the principal ray 212 may not have the highest brightness. As long as the light output is deflected by the polarization-dependent light deflection component 103 towards the optical lens system 204, it is consistent with... Figure 2 Compared to the previous configuration, this will improve light efficiency and reduce stray light.

[0046] The polarization-dependent light deflection component 103 can be a Pancharatnam-Berry phase optical element (PBPOE) made of a liquid crystal polymer. Those skilled in the art will understand that the PBPOE used herein is merely an example, and other types of deflection components can be used as long as they can perform the functions described herein.

[0047] In this embodiment, a Pancharatnam-Berry phase optic element 103 is used to alter the angular brightness distribution of the light emitted by the image generation unit 102, for example, directing more light to the optical lens system 104 / 204 and further to the exit pupil 105 and the eye 106. A circular polarizer or a quarter-wave plate can be placed between the image generation unit 102 and the PBPOE 103. In some embodiments, the deflection angle of the PBPOE 103 depends on the polarization state of the input light.

[0048] For example, the polarization-dependent light deflection component 103 can be a liquid crystal polymer film. The liquid crystal polymer film can be a geometrically phase-diffractive optical element with spatially varying optical axis orientation. The liquid crystal film can be prepared using polymerizable reactive mesogens and a photo-alignment method. In some embodiments, the Pancharatnam-Berry phase optical element 103 can be a liquid crystal polymer film. The optical axis of the liquid crystal film can be patterned to achieve the desired optical function. The liquid crystal pattern may vary across the entire surface of the display panel 102.

[0049] In another embodiment, the polarization-dependent light deflection component 103 is a meta-surface. The meta-surface can display a constant deflection angle for all display wavelengths at a single location on the image generation component 102. The meta-surface can be made of an all-dielectric material. The meta-surface can have several sublayers.

[0050] like Figure 3 As shown, the angular brightness distribution 322 can be asymmetrical relative to the normal of the surface of the image generation unit 102. The angular brightness distribution can vary at different locations on the display panel to increase the amount of light that can penetrate the optical lens system and enter the user's pupil.

[0051] The polarized light output generated by the image generation unit 102 has a narrow-angle brightness distribution 321, 322. For example, the full width at half maximum (FWHM) of the narrow-angle brightness distribution of the polarized light output is less than 30 degrees, 25 degrees, 20 degrees, 15 degrees, or 10 degrees.

[0052] In this way, most of the light emitted from the center of the image generating unit 102 can reach the optical lens system (lens group) 104 and then enter the eye 106. Therefore, the light component from the central part that is about to enter the eye 106 will increase, thereby reducing the stray light generated by the central light component.

[0053] Furthermore, the polarization-dependent light deflection component 103 alters (deflects) the angular brightness distribution of the light emitted by the image generation component 102 at the off-center field. The angular brightness distribution of the light at the off-center field (e.g., distribution 322) is adjusted by the polarization-dependent light deflection component 103 so that most of the light can penetrate the optical lens system 104 and reach the eye 106.

[0054] In some embodiments, the image generating unit 102 may be a liquid crystal display with directional backlighting. In some embodiments, the image generating unit 102 may be a light-emitting diode display with a strong cavity, the strong cavity being configured to achieve enhanced emission in a direction perpendicular to the display surface.

[0055] In this embodiment, an image generation component with polarized light output featuring a narrow angular brightness distribution and a polarization-dependent light deflection component are proposed. This combination can improve the display quality of optical display systems, especially near-eye displays. For example, if an optical display system uses only an image generation component with a narrow angular brightness distribution without a polarization-dependent light deflection component, uneven brightness distribution may appear throughout the displayed image. Furthermore, polarized light output makes it easier for the deflection component to efficiently deflect the light output.

[0056] In the example, the orientation of the liquid crystal polymer in the polarization-dependent light deflection component 103 is symmetrical about the optical axis of the optical lens system 104 / 204. With this arrangement, the angular brightness distribution can be adjusted by the polarization-dependent light deflection component 103 based on the distance to the center of the optical lens system 104 / 204, thereby obtaining a relatively uniform brightness distribution throughout the image.

[0057] The angular brightness distribution varies across different locations on the display panel to increase the amount of light that can penetrate the optical lens system and enter the viewer's pupil. For example, with the change in angular brightness distribution, more light is guided by the optical lens system 104 / 204 to the eye 106. Furthermore, the change in angular brightness distribution reduces the optical adjustment burden on the optical lens system 104 / 204 and improves the optical performance of the display system. For example, it may reduce distortion introduced by the optical lens system.

[0058] In one example, a polarization-dependent light deflection component 103 is used to control the narrow-angle brightness distribution. For instance, the polarization-dependent light deflection component 103 is used to control the narrow-angle brightness distribution such that light rays emitted perpendicular to the surface of the image generation component 102 are deflected by the polarization-dependent light deflection component 103 to a direction closer to the center of the optical lens system. The polarization-dependent light deflection component 103 can have a spatially varying deflection angle. This deflection angle may depend on the principal ray direction of the optical lens system. In this way, the polarization-dependent light deflection component 103 can increase the amount of display light that can penetrate the optical lens system and enter the user's pupil.

[0059] In another example, the narrow-angle brightness distribution can be adjusted using the polarization-dependent light deflection component 103 in a pixel-based manner. This allows for higher light efficiency and further reduction of stray light.

[0060] Furthermore, even though the relative position between the viewer and the near-eye display is fixed in most cases, the viewer may sometimes change posture or position, or the viewer may change location, which could lead to a change in relative position. Such changes are relatively small, but still affect the viewer's viewing experience. In this regard, the polarization-dependent light deflection component 103 can be an electrically controlled deflection optics element to track changes in eye position.

[0061] Figure 4 This indicates the liquid crystal orientation of the example polarization-dependent light deflection component 400 according to an embodiment of this disclosure. The azimuth angle of the liquid crystal molecules in the region where the principal ray is perpendicular to the display surface (i.e., the center of the image generation component 102) can be uniform, for example... Figure 4 The orientation 401 is shown. In the PBPOE-based polarization-dependent light deflection component 103, the liquid crystal orientation continuously changes at varying intervals Λ in regions where the principal ray is not parallel to the optical axis, such as ray 212. In some embodiments, the interval Λ of the liquid crystal orientation 403 around the periphery of the PBPOE 103 is smaller than the interval Λ of the orientation 402 between the center and the edge of the PBPOE 103. In some embodiments, the interval Λ of the liquid crystal orientation can be symmetrical about the center of the PBPOE 103. For example, the interval Λ of the liquid crystal orientation 404 can be the same as the interval Λ of the liquid crystal orientation 402.

[0062] Figure 5 This illustrates the liquid crystal orientation at the top of an example pixel 501 having red-green-blue sub-pixels according to an embodiment of this disclosure. In some embodiments of this disclosure, the polarization-dependent light deflection component 103 has different structures on the red, green, and blue sub-pixels. For example... Figure 5 As shown, the PBPOE 103 on top of each sub-pixel can have different orientations. Within each pixel, the spacing of the liquid crystal orientations may vary depending on the color channel. For example, the liquid crystal orientation on top of the red pixel 511 has the longest spacing, while the liquid crystal orientation on the blue pixel 513 has the shortest spacing. In some embodiments, within a single pixel region, when light passes through the PBPOE 103 on top of pixel 501, the peak directions of the angular brightness distributions of the red pixel 511, green pixel 512, and blue pixel 513 remain the same.

[0063] In various embodiments, by utilizing polarization-dependent light deflection components to control the angular brightness distribution of light, more light emitted by the image generation component can penetrate the optical lens system. By using different deflection patterns throughout the image generation component, the brightness and uniformity of the image observed by the user can be enhanced.

[0064] Figure 6 This refers to an electronic device according to an embodiment of this disclosure. For example... Figure 6 As shown, electronic device 600 includes optical display system 620 as described above. The electronic device can be a near-eye display device and can be used for virtual reality and / or augmented reality displays.

[0065] Although some specific embodiments of the present invention have been described in detail by way of example, those skilled in the art should understand that the above examples are for illustration only and are not intended to limit the scope of the present invention.

Claims

1. An optical display system, comprising: an image generation unit generating an image light output, wherein the image light output has a narrow angular luminance profile; and an optical lens system placed in front of the image generation unit directing the image light output to an eye of a viewer, wherein the image generation unit comprises: an image generation component generating a polarized light output; a polarization-dependent light deflection component configured to accept the polarized light output from the image generation component and increase an amount of the polarized light output that can enter an exit pupil of the optical lens system, and the polarized light output deflected by the polarization-dependent light deflection component has the narrow angular luminance profile, the polarization-dependent light deflection component is attached to a surface of the image generation component, and wherein the polarization-dependent light deflection component is capable of changing an angular luminance profile so that the angular luminance profile of the polarized light output generated by the image generation component is narrowed to form the narrow angular luminance profile.

2. The optical display system of claim 1, wherein the optical display system is a near-eye display module.

3. The optical display system of claim 1, wherein a full width at half maximum of the narrow angular luminance profile of the polarized light output is less than 30 degrees.

4. The optical display system of any one of claims 1-3, wherein the polarization- dependent light deflection component is a Pancharatnam-Berry phase optical element made of liquid crystal polymer.

5. The optical display system of claim 4, wherein an orientation of the liquid crystal polymer in the polarization-dependent light deflection component is symmetric about an optical axis of the optical lens system.

6. The optical display system of claim 5, wherein the angular luminance profile varies at different locations of the image generation unit to increase an amount of light that can penetrate the optical lens system and enter the eye of the viewer.

7. The optical display system of claim 1, wherein the narrow angular luminance profile is controlled by the polarization-dependent light deflection component.

8. The optical display system of claim 7, wherein the narrow angular luminance profile is controlled by the polarization-dependent light deflection component so that light rays emitted in a vertical direction of a surface of the image generation component are deflected by the polarization-dependent light deflection component to a direction close to a local chief ray of the optical lens system.

9. The optical display system of claim 7 or 8, wherein the narrow angular luminance profile is adjusted by the polarization-dependent light deflection component in a pixel-based manner.

10. The optical display system of claim 1, wherein the image generation component comprises a linear polarization-directive display device with a quarter wave plate, or a non-polarization-directive display device with a circular polarizer.

11. The optical display system of claim 1, wherein the optical lens system comprises optical reflective surfaces and optical refractive surfaces.

12. An electronic device comprising the optical display system of any one of claims 1-11.

Images