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CN-116635772-B - Light guide device

CN116635772BCN 116635772 BCN116635772 BCN 116635772BCN-116635772-B

Abstract

The device includes a light guide substrate for propagating light by internal reflection, the light guide substrate including a1 st portion and a2 nd portion as a 1-dimensional diffraction grating, the 1 st portion propagating the received light as a1 st light beam along a1 st path in the light guide substrate, the 2 nd portion propagating the received light as a2 nd light beam along a2 nd path in the light guide substrate, a1 st turn-back portion being a 1-dimensional diffraction grating for changing a direction of the 1 st path of the 1 st light beam, a2 nd turn-back portion being a 1-dimensional diffraction grating for changing a direction of the 2 nd path of the 2 nd light beam, and a light exit portion being a 2-dimensional diffraction grating for receiving the 1 st light beam and the 2 nd light beam from the 1 st turn-back portion and the 2 nd turn-back portion, combining the 1 st light beam and the 2 nd light beam and emitting the 1 st light beam to the outside of the light guide substrate. In the present device, the center of the smallest circle including the 1 st portion is located farther from the light emitting portion than the center of the smallest circle including the 2 nd portion in the surface of the light guide substrate, and the 1 st path passes through the region of the light guide substrate including the 2 nd portion.

Inventors

  • Zenko Tetsuya
  • KANAI NORIFUMI
  • KONO SHOGO

Assignees

  • 纳卢克斯株式会社

Dates

Publication Date
20260505
Application Date
20220524
Priority Date
20210818

Claims (10)

  1. 1. A light guide device is provided with: A light guide substrate that propagates light by internal reflection; A light incidence unit including a1 st portion and a 2 nd portion, each of which is a1 st-dimensional diffraction grating provided on the light guide substrate, the 1 st portion being configured to propagate the received light as a1 st light beam along a1 st path in the light guide substrate, and the 2 nd portion being configured to propagate the received light as a 2 nd light beam along a 2 nd path in the light guide substrate; A1 st turn-back part which is a 1-dimensional diffraction grating provided on the light guide substrate and is configured to change the direction of the 1 st path of the 1 st light beam; a2 nd turn-back part which is a 1-dimensional diffraction grating provided on the light guide substrate and is configured to change the direction of the 2 nd path of the 2 nd light beam, and A light emitting unit which is a 2-dimensional diffraction grating provided on the light guide substrate, and which is configured to receive the 1 st light beam from the 1 st turn-back unit and the 2 nd light beam from the 2 nd turn-back unit, combine the 1 st light beam and the 2 nd light beam, and emit the combined light beams to the outside of the light guide substrate, Wherein, the The light guide device is configured such that, on the surface of the light guide substrate, the center of the smallest circle including the 1 st portion is farther from the light exit portion than the center of the smallest circle including the 2 nd portion, and the 1 st path passes through the region of the light guide substrate where the 2 nd portion is provided.
  2. 2. The light guide device of claim 1, wherein, The light guide device is configured such that the area occupied by the 2 nd portion is 2% or more in a region of the light incident portion on a side away from the light emitting portion, based on a straight line passing through a groove direction of the 1st portion diffraction grating including a center of a smallest circle of the light incident portion, on a surface of the light guide substrate.
  3. 3. The light guide device of claim 1, wherein, The light guide device is configured such that the area occupied by the 1 st part is 10% or more in a region of the light incident part on the side closer to the light emitting part, based on a straight line passing through the groove direction of the 1 st part diffraction grating including the center of the smallest circle of the light incident part on the surface of the light guide substrate.
  4. 4. The light guide device of claim 1, wherein, In the plane of the light guide substrate, the boundary line between the 1 st and 2 nd portions of the light incident portion is configured such that a straight line intersecting the boundary line at two or more points is present, and the straight line is a straight line parallel to the groove direction of the diffraction grating of the 1 st portion.
  5. 5. The light guide device of claim 1, wherein, In the light guide device, the direction of the boundary line between the 1 st part and the 2 nd part in the light incident part is not single, and the maximum value of the difference of the angle of the line segment or the tangent line of the boundary line with respect to the reference direction is 75 degrees or more.
  6. 6. The light guide device of claim 1, wherein, In the light guide device, at least one of the 1 st and 2 nd portions has at least two portions separated from each other by the other of the 1 st and 2 nd portions on the surface of the light guide substrate.
  7. 7. The light guide device of claim 1, wherein, The light guide device is configured such that a horizontal direction and a vertical direction which are assumed when the light guide device is used are respectively determined as an x-axis and a y-axis, the inclination of the direction of the grooves of the 1-dimensional diffraction grating of the 1 st part with respect to the y-axis is within 5 degrees, and the inclination of the direction of the grooves of the 1-dimensional diffraction grating of the 2 nd part with respect to the x-axis is within 15 degrees.
  8. 8. The light guide device of claim 1, wherein, The light guide device is configured such that the period of the 1-dimensional diffraction grating of the 1 st part is equal to or less than the period of the 1-dimensional diffraction grating of the 2 nd part.
  9. 9. The light guide device of claim 1, wherein, The light guide device is configured such that the area occupied by the 2 nd portion is 2% or more in a region of the light incident portion on a side away from the light emitting portion, based on a straight line passing through a center of a smallest circle including the light incident portion and in a vertical direction which is assumed when the light guide device is used, in a surface of the light guide substrate.
  10. 10. The light guide device of claim 1, wherein, The light guide device is configured such that the 1 st part occupies 10% or more of the area of the light incident portion on the side closer to the light emitting portion, based on a straight line passing through the center of the smallest circle including the light incident portion and in the vertical direction that is assumed when the light guide device is used, in the surface of the light guide substrate.

Description

Light guide device Technical Field The present invention relates to a light guide for an augmented reality system. Background An augmented reality system (augmented REALITY SYSTEM) is being used that displays an image of a virtual object as part of the surrounding environment or displays an image of a virtual object overlapping the surrounding environment, thereby generating a virtual image of the augmented reality environment. As an example, the augmented reality system is implemented as a head-mounted display (head-mounted display) or other wearable device. The augmented reality system includes a light source that generates a virtual image, a light incidence portion that acquires the generated virtual image, a light guide portion that propagates the image acquired by the light incidence portion as light rays, and a light exit portion that receives the light rays from the light guide portion, and reforms the image based on the light rays and provides the image to a user. The light incident portion, the light emitting portion, and the light guiding portion are referred to as a light guiding device. Various light guide devices have been developed so far (patent documents 1 to 3). However, a light guide device having a sufficiently high light utilization efficiency from a light source has not been developed yet. Accordingly, there is a need for a light guide device having sufficiently high utilization efficiency of light from a light source. Prior art literature Patent literature Patent document 1, U.S. Pat. No. 7,803B 1 Patent document 2, US2020/0225498A1 Patent document 3, U.S. Pat. No.3,202, 0109273A1 Disclosure of Invention Problems to be solved by the invention The invention provides a light guide device with sufficiently high light utilization efficiency from a light source. Means for solving the problems The light guide device includes a light guide substrate that propagates light by internal reflection, a light incident portion that includes a1 st portion and a2 nd portion that are 1-dimensional diffraction gratings provided on the light guide substrate, respectively, the 1 st portion being configured to propagate received light as a1 st light beam along a1 st path in the light guide substrate, the 2 nd portion being configured to propagate received light as a2 nd light beam along a2 nd path in the light guide substrate, a1 st return portion that is a 1-dimensional diffraction grating provided on the light guide substrate and is configured to change a direction of the 1 st path of the 1 st light beam, a2 nd return portion that is a 1-dimensional diffraction grating provided on the light guide substrate and is configured to change a direction of the 2 nd path of the 2 nd light beam, and a 2-dimensional diffraction grating provided on the light guide substrate and is configured to receive the 1 st light beam from the 1 st light beam portion and the 2 nd light beam from the 2 nd return portion, and to combine the 1 st light beam and the 2 nd light beam to the outside the light guide substrate. In the light guide device of the present invention, the center of the smallest circle including the 1 st portion is located farther from the light emitting portion than the center of the smallest circle including the 2 nd portion in the surface of the light guide substrate, and the 1 st path passes through the region of the light guide substrate including the 2 nd portion. In the light guide device of the present invention, the center of the smallest circle including the 1 st portion is located farther from the light emitting portion than the center of the smallest circle including the 2 nd portion, and the 1 st path passes through the region of the light guide substrate where the 2 nd portion is provided, so that the diffraction efficiency when receiving light in the light incident portion can be improved as compared with the conventional light guide device in which the path of the light beam from one of the 1 st portion and the 2 nd portion toward the light emitting portion does not pass through the region of the light guide substrate where the other of the 1 st portion and the 2 nd portion is provided. Further, since the path of the light beam from the 1 st portion toward the light emitting portion passes through the region of the light guide substrate having the 2 nd portion, the degree of freedom in the manner of dividing the light incident portion into the 1 st portion and the 2 nd portion is significantly greater than that of the conventional light guide device in which the path of the light beam from one of the 1 st portion and the 2 nd portion toward the light emitting portion does not pass through the region of the light guide substrate having the other of the 1 st portion and the 2 nd portion. Therefore, the utilization efficiency of light from the light source can be improved by changing the method of dividing the light incident portion into the 1 st and 2 nd portions. In the light guide device accordin