Search

KR-102962771-B1 - Simplified holographic waveguide display using angle multiplexing

KR102962771B1KR 102962771 B1KR102962771 B1KR 102962771B1KR-102962771-B1

Abstract

A simplified holographic waveguide display utilizing angle multiplexing is provided. A waveguide display according to an embodiment of the present invention comprises a substrate, an incoupling grating provided on the substrate to incident pixel light, which is emitted from the display and collimated, into the substrate, and a multiplexing grating provided on the substrate to repeatedly reflect the pixel light incident into the substrate to repeatedly polarize it while expanding the emission path in a first direction, and then emit it from other positions to expand the emission path in a second direction. By doing so, the number of gratings in the augmented reality image providing device is reduced from three to two, thereby lowering the difficulty and cost of the process, while still providing a viewing area expanded in a two-dimensional direction identical to that of the conventional device.

Inventors

  • 염지운
  • 양윤모

Assignees

  • 한국전자기술연구원

Dates

Publication Date
20260511
Application Date
20230228

Claims (12)

  1. Substrate; An coupling grating provided on a substrate, which directs pixel light emitted from a display and collimated into the substrate; A multiplexing grating provided on a substrate, which repeatedly reflects pixel light incident into the substrate to expand the emission path in a first direction, repeatedly deflects it, and then emits it from other positions to expand the emission path in a second direction; A multiplexed grating is, Whenever pixel light is incident, a portion is reflected to proceed in the first direction, and the remainder is deflected to proceed in the second direction. Whenever pixel light reflected in the first direction enters, a portion is reflected and sent back in the first direction, and the remainder is deflected and sent in the second direction. Whenever pixel light deflected in the second direction enters, a portion is emitted and the remainder is reflected in the second direction, and A multiplexed grating is, Grid patterns that reflect and deflect in two directions are recorded on one side to divide pixel light into a first direction and a second direction and propagate it, and A waveguide display characterized by having grid patterns recorded therein that emit some of the pixel light proceeding in a second direction and deflect the rest to proceed in a second direction.
  2. In claim 1, A multiplexed grating is, A waveguide display characterized by performing the functions of an intermediate grating and an outcoupling grating of a waveguide display.
  3. In claim 2, A multiplexed grating is, A waveguide display characterized by being manufactured from a single medium.
  4. In claim 3, A waveguide display characterized by being fabricated with a holographic optical element.
  5. delete
  6. delete
  7. delete
  8. delete
  9. delete
  10. A step in which an incoupling grating provided on a substrate causes pixel light emitted from a display and collimated into the substrate; and A multiplexing grating provided on a substrate includes the step of repeatedly reflecting pixel light incident into the substrate to expand the emission path in a first direction, repeatedly deflecting it, and then emitting it from other positions to expand the emission path in a second direction; In the expansion phase, the multiplexing grid is, Whenever pixel light is incident, a portion is reflected to proceed in the first direction, and the remainder is deflected to proceed in the second direction. Whenever pixel light reflected in the first direction enters, a portion is reflected and sent back in the first direction, and the remainder is deflected and sent in the second direction. Whenever pixel light deflected in the second direction enters, a portion is emitted and the remainder is reflected in the second direction, and A multiplexed grating is, Grid patterns that reflect and deflect in two directions are recorded on one side to divide pixel light into a first direction and a second direction and propagate it, and A waveguide display method characterized by having grid patterns recorded therein that emit some of the pixel light proceeding in a second direction and deflect the rest to proceed in a second direction.
  11. Substrate; An incoupling grating provided on a substrate, which directs pixel light emitted from a display and collimated into the substrate; and A multiplexing grid is provided on a substrate and has grid patterns recorded on one side that reflect and deflect in two directions to divide pixel light into a first direction and a second direction and propagate it, and grid patterns recorded internally that deflect some of the pixel light propagating in the second direction to emit it and the remainder to propagate in the second direction; A multiplexed grating is, Whenever pixel light is incident, a portion is reflected to proceed in the first direction, and the remainder is deflected to proceed in the second direction. Whenever pixel light reflected in the first direction enters, a portion is reflected and sent back in the first direction, and the remainder is deflected and sent in the second direction. Whenever pixel light deflected in the second direction enters, a portion is emitted and the remainder is reflected in the second direction, and A multiplexed grating is, Grid patterns that reflect and deflect in two directions are recorded on one side to divide pixel light into a first direction and a second direction and propagate it, and A waveguide display characterized by having grid patterns recorded therein that emit some of the pixel light proceeding in a second direction and deflect the rest to proceed in a second direction.
  12. A step in which an incoupling grating provided on a substrate causes pixel light emitted from a display and collimated into the substrate; A multiplexing grating provided on a substrate reflects and deflects pixel light in two directions to divide and propagate pixel light in a first direction and a second direction using grating patterns recorded on one side; and The multiplexing grating includes the step of deflecting some of the pixel light proceeding in a second direction with the grating patterns recorded therein to emit some of it and to propagate the remainder in a second direction; A multiplexed grating is, Whenever pixel light is incident, a portion is reflected to proceed in the first direction, and the remainder is deflected to proceed in the second direction. Whenever pixel light reflected in the first direction enters, a portion is reflected and sent back in the first direction, and the remainder is deflected and sent in the second direction. Whenever pixel light deflected in the second direction enters, a portion is emitted and the remainder is reflected in the second direction, and A multiplexed grating is, Grid patterns that reflect and deflect in two directions are recorded on one side to divide pixel light into a first direction and a second direction and propagate it, and A waveguide display method characterized by having grid patterns recorded therein that emit some of the pixel light proceeding in a second direction and deflect the rest to proceed in a second direction.

Description

Simplified holographic waveguide display using angle multiplexing The present invention relates to an augmented reality display, and more specifically, to a waveguide-based wearable imaging device for providing augmented reality content images. A waveguide-based augmented reality optical device is composed of three types of incoupling gratings—an intermediate grating and an outcoupling grating—to secure a sufficient two-dimensional directional eyebox, and is designed to include three to four types of couplers by arranging two or more intermediate gratings as needed. At this time, since each coupling grating is highly difficult to process and the period and characteristics of each coupler are all different, manufacturers must accept an increase in process procedures and costs as the types and number of coupling gratings increase. Accordingly, measures are needed to simplify the process and lower costs by reducing the number of grids constituting the waveguide display. FIG. 1 is a conceptual diagram of a waveguide display, FIG. 2 is a drawing illustrating the structure of a waveguide display according to an embodiment of the present invention. FIG. 3 is a drawing illustrating an example of multiplexing of a multiplexing grid, Figure 4 is a conceptual diagram showing that the grid pattern presented in Figure 3 is multiplexed in the HOE to expand the starting area. The present invention will be described in more detail below with reference to the drawings. An embodiment of the present invention presents a simplified holographic waveguide display by reducing the number of gratings. By utilizing angle selectivity and multiplexing techniques, which are characteristics of holographic optical elements, the characteristics of intermediate gratings and outcoupler gratings are embedded within a single medium, thereby reducing the total number of grating generation regions from three or more to two. A waveguide display consists of a collimation unit that collimates light emitted from a display located on the side or top surface of the user, an incoupling grating that incidents the collimated light into a substrate, and an outcoupling grating located in front of the user's pupil that emits the light transmitted to the substrate. In this case, the in/out coupler can be composed of a diffractive optical element, a holographic optical element, a reflective surface, a partial reflective surface, etc. Since the light transmitted through the inside of the waveguide substrate is due to total internal reflection, it can propagate a long waveguide distance without a separate reflective coating, and it is easy to apply emission expansion technology that allows pixel light to be repeatedly emitted from different locations by adjusting the light emission efficiency of the out coupler. As shown in FIG. 1, in a waveguide display, a bundle of parallel light entering the incoupling grating (10) undergoes repetitive deflection in the intermediate grating (20) through total reflection within the waveguide and expands the output path in one direction. This repetitive deflection serves to expand and transmit the received pixel light to the outcoupling grid (30) located at the bottom of the intermediate grid (20), and finally, by undergoing repetitive light emission in the outcoupling grid (30) secondarily, it is possible to expand the emission path in a two-dimensional direction. Therefore, in order to sufficiently expand the viewing area in the two-dimensional direction, at least three types of grid patterns are required, indicated as an in-coupling grid (10), an intermediate grid (20), and an out-coupling grid (30). However, since the grid patterns are typically structures with a wavelength or less, increasing the number and types of grid patterns leads to an increase in the difficulty and cost of the manufacturing process. Accordingly, an embodiment of the present invention proposes a method to reduce the total number of required coupling gratings by using a multiplexed HOE (Holographic Optical Element) capable of performing the r-functions of an intermediate grating (20) and an outcoupling grating (30). A HOE is fabricated by recording the interference pattern of two light waves (a reference beam and a signal beam) entering from different directions onto a medium such as a photopolymer. The recorded interference pattern forms a periodically repeating volume grating within the holographic recording medium, and in the subsequent regeneration stage, if the incoming projected beam satisfies the Bragg condition of the volume grating, a regenerated beam is output through diffraction. If the incoming light deviates from the Bragg condition of the recorded volume grating, it has the characteristic of being transmitted without any separate diffraction, which is called wavelength and angle selectivity. Due to this selectivity, HOE can perform different optical functions for incident light with sufficiently different angles of incidence, and this