US-20260126659-A1 - OPTICAL MEMBER AND AR GLASSES HAVING OPTICAL MEMBER

US20260126659A1US 20260126659 A1US20260126659 A1US 20260126659A1US-20260126659-A1

Abstract

An optical member suitable for use in a head-mounted display that permits visual recognition of a background is provided. The optical member includes an optical film having a polarization control layer and an optical absorption anisotropic layer, and a light guide plate disposed on a side of the optical film on which the polarization control layer is provided. The light guide plate includes a diffraction element having a diffraction efficiency that varies with polarization direction. An angle between a transmittance central axis of the optical absorption anisotropic layer and a normal direction of the optical absorption anisotropic layer is from 0 degrees to 45 degrees. The polarization control layer is a quarter-wave film, and, in a use configuration, an angle between a slow axis of the quarter-wave film and a horizontal direction is from 0 degrees to 20 degrees.

Inventors

Fumitake Mitobe
Naoki KOITO

Assignees

FUJIFILM CORPORATION

Dates

Publication Date: 20260507
Application Date: 20260105
Priority Date: 20230719

Claims (10)

1 . An optical member comprising: an optical film having a polarization control layer and an optical absorption anisotropic layer; and a light guide plate disposed on a side of the optical film on which the polarization control layer is provided and including a diffraction element in which a diffraction efficiency changes depending on a polarization direction, wherein an angle between a transmittance central axis of the optical absorption anisotropic layer and a normal direction of the optical absorption anisotropic layer is 0° to 45°, in the optical film, a circular polarization degree in a direction at an angle of 60° with respect to a normal direction of the optical film at an azimuthal angle in at least one direction is 50% or more, a transmittance in the normal direction of the optical film is 55% or more, and a transmittance in a direction of the optical film at an angle of 30° with respect to the normal direction is 25% or more, the polarization control layer is a λ/4 film, and in a case where the optical member is arranged in a use configuration, an angle between a slow axis of the λ/4 film and a horizontal direction is 0° to 20°.
2 . An optical member comprising: an optical film having a polarization control layer and an optical absorption anisotropic layer; and a light guide plate disposed on a side of the optical film on which the polarization control layer is provided and including a diffraction element in which a diffraction efficiency changes depending on a polarization direction, wherein an angle between a transmittance central axis of the optical absorption anisotropic layer and a normal direction of the optical absorption anisotropic layer is 0° to 45°, in the optical film, a circular polarization degree in a direction at an angle of 60° with respect to a normal direction of the optical film at an azimuthal angle in at least one direction is 50% or more, a transmittance in the normal direction of the optical film is 55% or more, and a transmittance in a direction of the optical film at an angle of 30° with respect to the normal direction is 25% or more, and the polarization control layer includes a first λ/4 film and a second λ/4 film, and an angle between a slow axis of the first λ/4 film and a slow axis of the second λ/4 film is 30° to 60°.
3 . The optical member according to claim 2 , wherein the polarization control layer includes the first λ/4 film, the second λ/4 film, and a C-plate.
4 . An optical member comprising: an optical film having a polarization control layer and an optical absorption anisotropic layer; and a light guide plate disposed on a side of the optical film on which the polarization control layer is provided and including a diffraction element in which a diffraction efficiency changes depending on a polarization direction, wherein an angle between a transmittance central axis of the optical absorption anisotropic layer and a normal direction of the optical absorption anisotropic layer is 0° to 45°, in the optical film, a circular polarization degree in a direction at an angle of 60° with respect to a normal direction of the optical film at an azimuthal angle in at least one direction is 50% or more, a transmittance in the normal direction of the optical film is 55% or more, and a transmittance in a direction of the optical film at an angle of 30° with respect to the normal direction is 25% or more, and the polarization control layer is a layer containing a liquid crystal compound having a twisted structure of one or more layers.
5 . The optical member according to claim 4 , wherein the polarization control layer includes, in order from a side on which the diffraction element is disposed, the layer containing a liquid crystal compound having a twisted structure of one or more layers and a C-plate.
6 . AR glasses comprising: the optical member according to claim 1 .
7 . AR glasses comprising: the optical member according to claim 2 .
8 . AR glasses comprising: the optical member according to claim 3 .
9 . AR glasses comprising: the optical member according to claim 4 .
10 . AR glasses comprising: the optical member according to claim 5 .

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a Continuation of PCT International Application No. PCT/JP2024/021039 filed on Jun. 10, 2024, which claims priority under 35 U.S.C. § 119(a) to Japanese Patent Application No. 2023-117576 filed on Jul. 19, 2023. The above applications are hereby expressly incorporated by reference, in their entirety, into the present application. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical member and AR glasses having the optical member. 2. Description of the Related Art In recent years, a head-mounted display such as augmented reality (AR) glasses that superimpose and project a video on a background has appeared. The AR glasses are configured to include, for example, an image display element, a light guide plate, and a diffraction element, in which video light emitted from the image display element is diffracted by the diffraction element, is incident into the light guide plate, and is guided by the light guide plate such that the guided video light is diffracted by the diffraction element to display the video toward a viewer. Since the light guide plate is transparent, the AR glasses can project the video to superimpose the video on the background. In such AR glasses, external light incident from a specific oblique direction is diffracted toward a viewer while being color-separated by the diffraction element, and the color-separated external light is visually recognized by the viewer, which causes a problem that it is difficult to visually recognize an image displayed by the AR glasses, a view outside, or the like. An incidence angle (incidence angle oblique to a main surface of the diffraction element) at which external light is recognized changes depending on a pitch of the diffraction element. However, there is particularly a problem in that external light incident at 40° to 80° with respect to the normal line of the diffraction element is recognized. On the other hand, in some AR glasses, by reducing a transmittance of external light using a so-called neutral density filter (ND filter), a problem of visibility caused by incidence of external light is suppressed. SUMMARY OF THE INVENTION However, in a head-mounted display such as AR glasses in which a background can be visually recognized, in order to suppress the visibility problem caused by incidence of external light, it is necessary to reduce a transmittance of the ND filter in a case where the ND filter is used. Therefore, in the AR glasses or the like where the ND filter is used, not only the transmittance of light incident from the upper side but also the transmittance incident from the front direction, that is, the background decrease. As a result, in AR glasses or the like using the ND filter, the visibility problem caused by the external light can be suppressed, but the background may have poor visibility due to the background being darkened. An object of the present invention is to solve such a problem, and to provide an optical member that can be used in a head-mounted display such as AR glasses in which a background can be visually recognized, the optical member having excellent brightness of the background and capable of suppressing a visibility problem caused by external light incident from above a head of a user using the head-mounted display, and AR glasses using the optical member. The present inventors have found that the above-described objects can be achieved by the following configurations. [1] An optical member comprising: an optical film having a polarization control layer and an optical absorption anisotropic layer; anda light guide plate disposed on a side of the optical film on which the polarization control layer is provided and including a diffraction element in which a diffraction efficiency changes depending on a polarization direction,in which an angle between a transmittance central axis of the optical absorption anisotropic layer and a normal direction of the optical absorption anisotropic layer is 0° to 45°,in the optical film, a circular polarization degree in a direction at an angle of 60° with respect to a normal direction of the optical film at an azimuthal angle in at least one direction is 50% or more, a transmittance in the normal direction of the optical film is 55% or more, and a transmittance in a direction of the optical film at an angle of 30° with respect to the normal direction is 25% or more,the polarization control layer is a λ/4 film, andin a case where the optical member is arranged in a use configuration, an angle between a slow axis of the λ/4 film and a horizontal direction is 0° to 20°. [2] An optical member comprising: an optical film having a polarization control layer and an optical absorption anisotropic layer; anda light guide plate disposed on a side of the optical film on which the polarization control layer is provided and including a diffraction element in which a diffraction efficiency chang