US-12619094-B2 - Systems and methods for increasing display system fill factor

US12619094B2US 12619094 B2US12619094 B2US 12619094B2US-12619094-B2

Abstract

The disclosed system may include a display; a lens; and a diffractive optical element, where the diffractive optical element includes at least one Pancharatnam-Berry phase grating and is configured to increase a fill factor of the display when the lens is used to magnify the display. Various other apparatuses, systems, and methods are also disclosed.

Inventors

Yun-Han Lee
Chulwoo Oh
Hyunmin SONG
Xinyu Zhu
Zhang Jia
Yongmin PARK
Jiawei Lu

Assignees

META PLATFORMS TECHNOLOGIES, LLC

Dates

Publication Date: 20260505
Application Date: 20231128

Claims (14)

1 . An apparatus comprising a diffractive optical element, wherein the diffractive optical element is configured to increase a fill factor of a display when a lens is used to magnify the display, wherein the diffractive optical element comprises at least one Pancharatnam-Berry phase grating, wherein the at least one Pancharatnam-Berry phase grating comprises at least one one-dimensional Pancharatnam-Berry phase grating, and wherein the at least one one-dimensional Pancharatnam-Berry phase grating comprises: a first one-dimensional Pancharatnam-Berry phase grating that diffracts light along a first dimension; and a second one-dimensional Pancharatnam-Berry phase grating that diffracts light along a second dimension orthogonal to the first dimension.
2 . The apparatus of claim 1 , further comprising at least one waveplate disposed to modulate a polarization state of input light to the at least one Pancharatnam-Berry phase grating.
3 . The apparatus of claim 1 , wherein the at least one Pancharatnam-Berry phase grating comprises at least one two-dimensional Pancharatnam-Berry phase grating.
4 . The apparatus of claim 1 , wherein the diffractive optical element is configured to be positioned adjacent to the display.
5 . The apparatus of claim 1 , wherein the diffractive optical element is configured to be positioned adjacent to the lens.
6 . The apparatus of claim 1 , further comprising at least one color-selective waveplate that controls what color is affected by the diffractive optical element.
7 . The apparatus of claim 1 , wherein the diffractive optical element comprises a film.
8 . A system comprising: a display; a lens; and a diffractive optical element, wherein the diffractive optical element is configured to increase a fill factor of the display when the lens is used to magnify the display, wherein the diffractive optical element comprises at least one Pancharatnam-Berry phase grating, wherein the at least one Pancharatnam-Berry phase grating comprises at least one one-dimensional Pancharatnam-Berry phase grating, and wherein the at least one one-dimensional Pancharatnam-Berry phase grating comprises: a first one-dimensional Pancharatnam-Berry phase grating that diffracts light along a first dimension; and a second one-dimensional Pancharatnam-Berry phase grating that diffracts light along a second dimension orthogonal to the first dimension.
9 . The system of claim 8 , further comprising at least one waveplate disposed to modulate a polarization state of input light to the at least one Pancharatnam-Berry phase grating.
10 . The system of claim 8 , wherein the at least one Pancharatnam-Berry phase grating comprises at least one two-dimensional Pancharatnam-Berry phase grating.
11 . The system of claim 8 , wherein the diffractive optical element is configured to be positioned adjacent to the display.
12 . The system of claim 8 , wherein the diffractive optical element is configured to be positioned adjacent to the lens.
13 . The system of claim 8 , further comprising at least one color-selective waveplate that controls what color is affected by the diffractive optical element.
14 . A method of manufacture comprising: positioning a lens to magnify a display; and positioning a diffractive optical element to increase a fill factor of the display when the lens is used to magnify the display, wherein the diffractive optical element comprises at least one Pancharatnam-Berry phase grating, wherein the at least one Pancharatnam-Berry phase grating comprises at least one one-dimensional Pancharatnam-Berry phase grating, and wherein the at least one one-dimensional Pancharatnam-Berry phase grating comprises: a first one-dimensional Pancharatnam-Berry phase grating that diffracts light along a first dimension; and a second one-dimensional Pancharatnam-Berry phase grating that diffracts light along a second dimension orthogonal to the first dimension.

Description

CROSS REFERENCE TO RELATED APPLICATION This application claims the benefit of U.S. Provisional Application No. 63/479,222, filed 10 Jan. 2023, the disclosure of which is incorporated, in its entirety, by this reference. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings illustrate a number of exemplary embodiments and are a part of the specification. Together with the following description, these drawings demonstrate and explain various principles of the present disclosure. FIG. 1 illustrates an example display with an array of subpixels. FIG. 2 illustrates an example fill factor increase of an example pixel. FIG. 3 illustrates an example display system. FIG. 4 illustrates an example display system with increased fill factor. FIG. 5 illustrates virtual rays created by the display system with increased fill factor of FIG. 4. FIG. 6. is a top view of an example Pancharatnam-Berry phase (PBP) grating film. FIG. 7 is a profile view of the PBP grating film of FIG. 6. FIG. 8 illustrates an example device for fill factor expansion. FIG. 9 illustrates a diffractive optical element that diffracts in two dimensions. FIG. 10 illustrates a device with a series of diffractive optical elements with color-selective waveplates. FIG. 11 illustrates an example fill factor increase of an example pixel. FIGS. 12A and 12B illustrate example placements of diffractive optical elements in display systems for increased fill factor. FIG. 13 is an illustration of exemplary augmented-reality glasses that may be used in connection with embodiments of this disclosure. FIG. 14 is an illustration of an exemplary virtual-reality headset that may be used in connection with embodiments of this disclosure. Throughout the drawings, identical reference characters and descriptions indicate similar, but not necessarily identical, elements. While the exemplary embodiments described herein are susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. However, the exemplary embodiments described herein are not intended to be limited to the particular forms disclosed. Rather, the present disclosure covers all modifications, equivalents, and alternatives falling within the scope of the appended claims. DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS When a lens magnifies a display (as with a virtual reality system), gaps between pixels and/or subpixels may also be magnified, creating a “screen-door” effect of a visible dark grid. The screen-door effect may negatively impact perceived image quality, potentially resulting in a loss of sense of immersion (in the case of virtual reality or augmented reality system) or user dissatisfaction. To reduce or eliminate the screen-door effect, an optical element may precisely diffract images of pixels and/or subpixels into multiple images to increase their effective fill factor (e.g., reducing the area of the gaps). In some examples, a Pancharatnam-Berry phase (PBP) optical element may be adapted to perform the precise diffraction. The PBP element may be placed in a variety of places, including, e.g., near the lens (e.g., on the eye side). In some examples, two one-dimensional PBP gratings may be used-one to horizontally expand pixel images, another to vertically expand pixel images. In another example, a two-dimensional PBP grating may be used. Because different wavelengths may be affected differently by the PBP, in some examples multiple PBPs (e.g., one each for blue, green, and red) may be paired with corresponding color-selective waveplates. By increasing the fill factor of magnified displays and reducing the screen-door effect, the apparatuses and systems described herein may improve the perceived image quality of magnified displays and, in the case of virtual reality and augmented reality systems, increase the users' sense of immersion. Detailed descriptions of example display systems will be provided in connection with FIGS. 1-5, 11, 12A, and 12B; detailed descriptions of example diffractive optical elements will be provided in connection with FIGS. 6-10; detailed descriptions of example virtual reality and augmented reality systems will be provided in connection with FIGS. 13-14. FIG. 1 illustrates an example display 100 with an array of subpixels. As shown in FIG. 1, display 100 may include an array of pixels, including a pixel 108. Pixel 108 may include multiple subpixels, including a subpixel 102 (e.g., a blue subpixel), a subpixel 104 (e.g., a green subpixel), and a subpixel 106 (e.g., a red subpixel). As can be appreciated from FIG. 1, subpixels 102, 104, and 106 may leave a gap 110 between each other and between themselves and the subpixels of adjacent pixels. This gap, as repeated throughout display 100, may contribute to a screen-door effect—e.g., a perceptible black grid—in display 100, which may be made apparent and/or may become more intense when display 100 is magnified (e.g.