Optical display device

Abstract

The present invention discloses an optical display device, in which a coupling device couples light output from an image generating device into an optical extension waveguide. The optical extension waveguide includes at least a first reflective surface array and a second reflective surface array, and the light entering the optical extension waveguide passes through the first reflective surface array and the second reflective surface array in sequence, and each reflective surface array expands the light propagated through the optical extension waveguide in a one-dimensional direction, and realizes the expansion of the light entering the optical extension waveguide in a two-dimensional direction, and emits the light out of the optical extension waveguide to form an image. At least one of the first reflective surface of the first reflective surface array and the second reflective surface of the second reflective surface array is at least partially curved, and the first reflective surface and / or the second reflective surface change the light emission angle so that the image distance formed from the light emitted by the optical extension waveguide meets a predetermined requirement. Therefore, the present invention can change the image distance, is suitable for users with visual impairments, and has a thin and light structure.

Description

cross reference

[0001] This application claims priority to a Chinese patent application filed with the China Patent Office on January 20, 2022, bearing application number 202210065963.4, and entitled "Optical Display Device", the entire contents of which are incorporated herein by reference. [Technical field]

[0002] The present invention relates to the field of optical devices, and in particular to optical display devices. [Background technology]

[0003] Near-eye display is a technology field that has attracted a lot of attention, and its optical system includes microdisplay and optical element. At present, there are many optical solutions for near-eye display on the market.

[0004] The arrayed waveguide solution uses semi-transparent and semi-reflective optical surfaces to realize expansion and exit pupil for light, and follows the law of reflection that the angle of incidence is equal to the angle of reflection, so there is no dispersion effect on the incident light of the three primary colors forming a full-color display, and it can ensure that the formed image has no obvious color shift, meeting the most basic requirements of a display device, and has obvious advantages in optimizing the design of head-mounted devices and beautifying the aesthetics.

[0005] However, due to the characteristic of forming an image at an infinite distance, the display device according to this solution is applied to people with a visual acuity of about 1.2, while the visual acuity of normal people (including vision correction) is about 1.0, so when using such a display device, the wearer cannot see a clear and good image, which brings great trouble to the user. To solve this problem, the mainstream solution uses an external device for assistance and adjustment, which not only increases the volume and weight of the display device, but also reduces the comfort and perception experience of the user. Summary of the Invention [Problem to be solved by the invention]

[0006] In view of this, an object of the present invention is to provide an optical display device that can change the focused image distance, is suitable for users with visual impairments, and has a thin and lightweight structure. [Means for solving the problem]

[0007] To achieve the above objectives, the present invention provides the following technical solutions: An optical display device, comprising: an image generating device, a coupling device, and an optical extension waveguide, the coupling device being corresponding to the image generating device and coupling light output from the image generating device to the optical extension waveguide; The optical expansion waveguide includes at least a first reflective surface array and a second reflective surface array, and the light entering the optical expansion waveguide passes through the first reflective surface array and the second reflective surface array in order, and the first reflective surface array and the second reflective surface array each expand the light propagated through the optical expansion waveguide in a one-dimensional direction, and realize the expansion of the light entering the optical expansion waveguide in a two-dimensional direction, and emit the light out of the optical expansion waveguide to form an image; By making at least a portion of at least one of the first reflective surface of the first reflective surface array and the second reflective surface of the second reflective surface array curved, the image distance formed from the light emitted by the optical expansion waveguide meets a specified requirement.

[0008] Preferably, at least a portion of the first reflecting surface of the first reflecting surface array is curved, and the first reflecting surface diverges the light reflected by the first reflecting surface; Alternatively, at least a local portion of the second reflecting surface of the second reflecting surface array is curved, and the second reflecting surface diverges the light reflected by the second reflecting surface.

[0009] Preferably, the first reflecting surface array expands the light propagated through the optical expansion waveguide in a first dimensional direction, and each of the first reflecting surfaces forms an inclination angle with respect to the first dimensional direction.

[0010] Preferably, the optically enhanced waveguide includes a first waveguide base, the first reflective surface array is disposed within the first waveguide base, the first waveguide base includes at least a first set of opposing surfaces, and light entering the first waveguide base is reflected by each of the first set of opposing surfaces and propagates forward.

[0011] Preferably, at least one of the first set of opposing surfaces is curved, at least locally, to change the angle at which reflected light from that surface strikes the first reflecting surface, thereby helping to ensure that the image distance formed from the light emitted by the optical expansion waveguide meets a specified requirement.

[0012] Preferably, at least one surface of the first set of opposing surfaces is divergent in the light reflected therefrom.

[0013] Preferably, the optically enhanced waveguide includes a second waveguide base, the second reflective surface array is disposed within the second waveguide base, the second waveguide base includes at least a third set of opposing surfaces, and light entering the second waveguide base is reflected by each of the third set of opposing surfaces to propagate forward.

[0014] Preferably, each of the second reflecting surfaces forms an inclination angle with respect to any one of the third set of opposing surfaces.

[0015] Preferably, the inclination angle formed by the second reflecting surface with respect to one surface of the third set of opposing surfaces as a coupling output surface is greater than 0° and less than 45°, and when the second reflecting surface rotates along a counterclockwise direction with respect to the one surface, the inclination angle formed by the second reflecting surface with respect to the surface is positive.

[0016] Preferably, at least one of the third set of opposing surfaces is curved, at least locally, to change the angle at which light reflected from that surface strikes the second reflective surface, thereby helping to ensure that the image distance formed from the light emitted by the optical expansion waveguide meets a specified requirement.

[0017] Preferably, at least one surface of the third set of opposing surfaces diverges light reflected by that surface.

[0018] Preferably, the optically expanded waveguide includes a first waveguide base and a second waveguide base, the first reflective surface array is disposed in the first waveguide base, and the second reflective surface array is disposed in the second waveguide base; The first waveguide base further includes a first coupling output surface that causes the reflected light of the first reflecting surface to be emitted outside the first waveguide base, and the second waveguide base further includes a second coupling input surface that causes the light emitted by the first waveguide base to enter the second waveguide base, and the first coupling output surface and the second coupling input surface are optically coaxial.

[0019] Preferably, the coupling device splits the light output from the image generating device into a first beam and a second beam having different polarization states, and couples the first beam and the second beam into the optical extension waveguide, respectively.

[0020] Preferably, the combining device includes a polarization splitting unit, an optical conversion unit, a collimating unit and a optical selection unit, the polarization splitting unit performs polarization splitting on the light output from the image generating device, the optical conversion unit realizes mutual conversion of two lights having different polarization states, the collimating unit collimates the light to uniformly distribute the optical energy, and the optical selection unit inputs the light corresponding to the polarization state among the light passing through the optical selection unit into the optical extension waveguide. Effect of the Invention

[0021] As can be seen from the above technical solutions, in the optical display device provided by the present invention, the coupling device couples the light output from the image generating device into the optical extension waveguide. The optical extension waveguide includes at least a first reflective surface array and a second reflective surface array, and the light entering the optical extension waveguide passes through the first reflective surface array and the second reflective surface array in sequence, and each reflective surface array expands the light propagated through the optical extension waveguide in a one-dimensional direction, and realizes the expansion of the light entering the optical extension waveguide in a two-dimensional direction, and emits the light out of the optical extension waveguide to form an image. At least one of the first reflective surface of the first reflective surface array and the second reflective surface of the second reflective surface array is curved at least locally, so that the first reflective surface and / or the second reflective surface change the light emission angle, and the image distance formed from the light emitted by the optical extension waveguide meets a predetermined requirement. Therefore, the optical display device of the present invention can change the image distance, is suitable for users with visual impairments, and has a thin and light structure. [Brief description of the drawings]

[0022] In order to more clearly describe the technical solutions in the embodiments of the present invention or the prior art, the following briefly introduces the necessary drawings in the embodiments or prior art description, and the drawings described below are merely some embodiments of the present invention, and other drawings can be obtained based on these drawings on the premise that no inventive effort is required for those skilled in the art. [Figure 1] 1 is a schematic diagram of light propagation in an optical display device provided by an embodiment of the present invention, in which a coupling device couples output light of an image generating device into an optical extension waveguide. [Diagram 2] FIG. 2 is a schematic diagram of light propagation on a first reflecting surface in one embodiment of the present invention. [Figure 3-1] FIG. 3-3 is a left side view of the optical extension waveguide of FIG. [Figure 3-2] FIG. 2 is a front view of an optical extension waveguide provided by one embodiment of the present invention. [Figure 4] FIG. 2 is a schematic diagram of a first waveguide-based ray propagation in one embodiment of the present invention; [Diagram 5]4 is a schematic diagram of ray propagation through one surface of a first set of opposing surfaces and a first reflecting surface in one embodiment of the present invention. [Figure 6] FIG. 13 is a schematic diagram of a second waveguide-based ray propagation in one embodiment of the present invention. [Figure 7] FIG. 2 is a schematic diagram of a light ray propagating through a second waveguide base to form a corresponding effective light passing aperture in one embodiment of the present invention. [Figure 8] FIG. 2 is a schematic diagram of a waveguide-based reflector using a curved surface and the structural parameters of the surface in one embodiment of the present invention. [Figure 9-1] FIG. 2 is a schematic diagram of a curved surface used for one of the opposing surfaces of the waveguide base in one of the embodiments of the present invention. [Figure 9-2] FIG. 13 is a schematic diagram of another curved surface used by any of the opposing surfaces of the waveguide base of any of the embodiments of the present invention. [Figure 10-1-10-4] 2A-2C are schematic diagrams of four embodiments of a first waveguide-based first coupling output surface and a second waveguide-based second coupling input surface according to an embodiment of the present invention; [Figure 11-1-11-3] 3A to 3C are schematic diagrams of three embodiments of the arrangement positions of a first waveguide base and a second waveguide base in an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] In order to allow those skilled in the art to better understand the technical solution of the present invention, the following clearly and completely describes the technical solution of the embodiments of the present invention in combination with the drawings of the embodiments of the present invention, and the described embodiments are not all the embodiments, but only some embodiments of the present invention. Based on the embodiments of the present invention, on the premise that those skilled in the art do not make any inventive efforts, all other embodiments obtained fall within the protection scope of the present invention.

[0024] The present embodiment provides an optical display device, comprising: an image generating device; a coupling device; and an optical extension waveguide, the coupling device being adapted to couple light output from the image generating device to the optical extension waveguide; The optical expansion waveguide includes at least a first reflective surface array and a second reflective surface array, and the light entering the optical expansion waveguide passes through the first reflective surface array and the second reflective surface array in order, and the first reflective surface array and the second reflective surface array each expand the light propagated through the optical expansion waveguide in a one-dimensional direction, and realize the expansion of the light entering the optical expansion waveguide in a two-dimensional direction, and emit the light out of the optical expansion waveguide to form an image; By making at least a portion of at least one of the first reflective surface of the first reflective surface array and the second reflective surface of the second reflective surface array curved, the image distance formed from the light emitted by the optical expansion waveguide meets a specified requirement.

[0025] The light entering the optical expansion waveguide is propagated through the optical expansion waveguide, and passes through the first reflective surface array and the second reflective surface array in order to realize two-dimensional expansion of the light entering the optical expansion waveguide, and the light is emitted out of the optical expansion waveguide, and the emitted light enters the user's eye, allowing the user to see the image.

[0026] The image distance formed from the light emitted by the optical expansion waveguide is the distance from a viewing position to a corresponding virtual image of the image formed from the light emitted by the optical expansion waveguide.

[0027] In addition, if at least a portion of the first reflecting surface is curved, the reflection angle of the light at the first reflecting surface can be changed by the curved surface, and the exit angle of the light emitted from the optical extension waveguide can be changed. If at least a portion of the second reflecting surface is curved, the reflection angle of the light at the second reflecting surface can be changed by the curved surface, and the exit angle of the light emitted from the optical extension waveguide can be changed. Therefore, by using a curved surface for at least one of the first reflecting surface and the second reflecting surface, the optical extension waveguide can change the exit angle at which the light is emitted, and the image distance formed from the output light of the optical display device can be changed so that the image distance satisfies a predetermined requirement.

[0028] Therefore, the optical display device of this embodiment can change the focused image distance, which is suitable for users with visual impairments, so that users with visual impairments can see clear and good images, and the structure of the optical expansion waveguide in the optical display device of this embodiment is thin and light.

[0029] The image generating device outputs light with image information. In this embodiment, the type and structure of the image generating device are not specifically limited. Preferably, considering the weight and volume of the entire optical display device, the image generating device may use a miniaturized display chip, and may use, but is not limited to, a Liquid Crystal on Silicon (LOCS) display screen, a Liquid Crystal Display (LCD) display screen, an Organic Light-Emitting Diode (OLED) display screen, a MicroLED display screen, a miniLED display screen, or a Digital Light Processing (DLP) display screen.

[0030] In practical applications, based on different application scenarios, the light weight and small size of the head mounted display device are considered, and factors such as the uniformity of brightness at each point of the image source, output light effect, brightness requirements, resolution and size limitations are taken into consideration to select an image generating device with appropriate volume, uniform brightness and high resolution.

[0031] Preferably, the coupling device separates the light output from the image generating device into a first beam and a second beam having different polarization states, and couples the first beam and the second beam into the optical extension waveguide, respectively. The coupling device performs polarization splitting on the output light from the image generating device, couples the beams into the optical extension waveguide, and propagates and expands the beams through the optical extension waveguide, thereby making the brightness of the image formed from the output light uniform.

[0032] Preferably, the coupling device includes a polarization splitting unit, a light conversion unit, a collimating unit, and a light selection unit, the polarization splitting unit performs polarization splitting on the light output from the image generating device, the light conversion unit realizes mutual conversion of two lights having different polarization states, the collimating unit collimates the light to uniformly distribute the light energy, and the light selection unit inputs the light corresponding to the polarization state of the light passing through the light selection unit into the optical extension waveguide. In this way, the coupling device performs polarization splitting on the light output from the image generating device and couples and inputs the light into the optical extension waveguides respectively, and uniformly distributes each portion of the light energy coupled and input into the input optical extension waveguides respectively.

[0033] In this embodiment, the specific optical structure of the coupling device is not limited, and the light output from the image generating device can be coupled into the optical extension waveguide. For example, refer to FIG. 1, which is a schematic diagram of light propagation in an optical display device provided by one embodiment, in which the coupling device couples the output light of the image generating device into the optical extension waveguide. As shown in the drawing, the coupling device 301 includes a polarizing splitting unit 401, a first light converting unit 402, a first collimating unit 403, a second light converting unit 404, a second collimating unit 405, a first light selecting unit 406 and a second light selecting unit 407.

[0034] The polarization splitting unit 401 splits the output light of the image generating device 300 into light of a first polarization state and light of a second polarization state, the light of the first polarization state is reflected and passes through the first optical conversion unit 402 and the first collimating unit 403 in order, the first collimating unit 403 collimates and reflects the light, so that the light of the first polarization state is converted into light of a second polarization state after passing through the first optical conversion unit 402 twice. The light of the second polarization state formed by the conversion passes through the polarization splitting unit 401 and enters the first optical selection unit 406, where it is reflected and enters the optical extension waveguide 302.

[0035] The light in the second polarization state separated by the polarization splitting unit 401 is transmitted and sequentially enters the second optical conversion unit 404 and the second collimating unit 405, and the second collimating unit 405 collimates and reflects the light, so that the corresponding portion of the light passes through the second optical conversion unit 404 twice and is converted to light in the first polarization state. The light in the first polarization state formed by the conversion is reflected when passing through the polarization splitting unit 401, and is reflected when entering the second optical splitting selection unit 407 and enters the input optical extension waveguide 302. The vibration directions of the light in the first polarization state and the light in the second polarization state are perpendicular to each other, and are P light and S light, respectively.

[0036] Here, the coupling device of FIG. 1 is merely an exemplary illustration of an embodiment, and in other embodiments, other optical structures may be used for the coupling device, all of which are within the protection scope of the present invention.

[0037] Hereinafter, an embodiment of the optical extension waveguide of the optical display device will be described.

[0038] In this embodiment, as long as at least a portion of the first reflecting surface of the first reflecting surface array is curved, there is no specific limitation on the shape of the curved surface included in the first reflecting surface and the size of the curved surface area, and it is sufficient that the emission angle of the light emitted by the optical extension waveguide is changed and the image distance formed from the light emitted by the optical extension waveguide meets a predetermined requirement. The curved surface included in the first reflecting surface may be a curved surface having a certain curvature or a free-form surface. Preferably, the curved surface is used for the first reflecting surface to diverge or converge the light reflected by the first reflecting surface.

[0039] In this embodiment, as long as at least a portion of the second reflecting surface of the second reflecting surface array is curved, there is no specific limitation on the shape of the curved surface included in the second reflecting surface and the size of the curved surface area, and it is sufficient that the emission angle of the light emitted by the optical extension waveguide is changed and the image distance formed from the light emitted by the optical extension waveguide meets a predetermined requirement. The curved surface included in the second reflecting surface may be a curved surface having a certain curvature or a free-form surface. Preferably, the curved surface is used for the second reflecting surface to diverge or converge the light reflected by the second reflecting surface.

[0040] For example, as shown in FIG. 2, FIG. 2 is a schematic diagram of light propagation at a first reflecting surface in one embodiment. As shown in the drawing, the light beams L1 and L2 reflected by the waveguide surface 100 are respectively incident on the first reflecting surface 101, and the first reflecting surface 101 is a curved surface. The reflected light beams L1' and L2' are formed through the first reflecting surface 101. The light beams L1 and L2 are reflected through the reference plane 102 of the first reflecting surface 101, and the reflected light beams L1'' and L2'' are formed through the reference plane 102 of the first reflecting surface 101, and the reflected light beams L1' and L2' are divergent. This reduces the image distance formed from the light emitted by the optical expansion waveguide. For a user with visual impairment, the image can be focused on the retina of the user with visual impairment.

[0041] The above is based on Figure 2 and takes the propagation of light on the first reflecting surface as an example to explain the principle of using a curved surface for the first reflecting surface to change the image distance. Similarly, using a curved surface for the second reflecting surface to change the image distance also follows the above principle.

[0042] The first reflective surface array expands the light propagated through the optical expansion waveguide in a first dimensional direction, and each of the first reflective surfaces forms an inclination angle with respect to the first dimensional direction. The inclination angle of the first reflective surface with respect to the first dimensional direction refers to the chord of the first reflective surface and the first dimensional direction being neither parallel nor perpendicular. Correspondingly, the inclination angle formed by the first reflective surface with respect to the first dimensional direction is the included angle between the chord of the first reflective surface and the first dimensional direction. When the light propagated through the optical expansion waveguide is incident on the first reflective surface, a portion of the light energy is transmitted through the first reflective surface and continues to propagate, and another portion of the light energy is reflected, and the first reflective surface array expands the light propagated through the optical expansion waveguide in the first dimensional direction.

[0043] In this embodiment, the magnitude of the inclination angle formed by each of the first reflecting surfaces with respect to the first dimension is not limited, as long as the expansion of the light propagated through the optical expansion waveguide in the first dimension is realized. In practical application, the expansion requirement of the light in the first dimension is set according to the size of the optical expansion waveguide, and preferably, the structure of the optical expansion waveguide is thin and light while meeting the expansion requirement of the light.

[0044] For the projection surface of the first reflecting surface on a plane parallel to the first dimension direction, the plane parallel to the first dimension direction is located on the light reflecting side of the first reflecting surface and determines the light passing aperture of the output light of the optical expansion waveguide in the first dimension direction. For the optical display device, the light passing aperture of the output light of the optical expansion waveguide in the first dimension direction must ensure that the image from the image generating device is fully expanded, that is, the image formed by the output light of the optical expansion waveguide contains the complete information of the image in the first dimension direction.

[0045] Preferably, the optically enhanced waveguide includes a first waveguide base, the first reflective surface array is disposed within the first waveguide base, the first waveguide base includes at least a first set of opposing surfaces, and the light entering the first waveguide base is reflected by each of the first set of opposing surfaces and propagates forward. Specifically, the total internal reflection condition is satisfied when the light is incident on each of the first set of opposing surfaces. The first set of opposing surfaces may or may not be parallel to each other, and the light may be reflected by each of the first set of opposing surfaces and propagates forward.

[0046] Preferably, the first waveguide base further includes a second set of opposing surfaces, the second set of opposing surfaces and the first set of opposing surfaces form a closed cross section, and the light entering the first waveguide base is reflected and propagated forward by each of the first set of opposing surfaces and the second set of opposing surfaces. Specifically, when the light is incident on each of the second set of opposing surfaces, the total reflection condition is satisfied. The second set of opposing surfaces may or may not be parallel to each other, as long as the light is reflected and propagated forward by each of the second set of opposing surfaces.

[0047] For example, referring to Fig. 3-1, Fig. 3-2 and Fig. 4 in combination, Fig. 3-1 is a left side view of the optical extension waveguide of Fig. 3-2, Fig. 3-2 is a front view of the optical extension waveguide provided by one embodiment, and Fig. 4 is a schematic diagram of light propagation in the first waveguide base in one embodiment. As shown in the drawing, within the cross section formed by four surfaces 1-A, 1-B, 1-C and 1-D of the first waveguide base 1, the light entering the first waveguide base 1 is reflected by each surface and propagates forward. During the propagation process, when the light meets the first reflecting surface 101, it reflects a part of the light energy at a certain energy ratio, so that the light is coupled into the second waveguide base 2.

[0048] In the first waveguide base 1 of Fig. 4, the first set of opposing surfaces 1-A and 1-B are parallel to each other, and the second set of opposing surfaces 1-C and 1-D are parallel to each other, and Fig. 4 is merely illustrative. In other embodiments, the first set of opposing surfaces may not be parallel, and the second set of opposing surfaces may not be parallel.

[0049] In one preferred embodiment, at least one surface of the first set of opposing surfaces is curved at least locally to change the incident angle of the reflected light from the surface to the first reflecting surface, thereby helping to ensure that the image distance formed from the light emitted from the optical expansion waveguide meets a predetermined requirement. At least one surface of the first set of opposing surfaces is curved at least locally to change the reflection angle of the light after passing through the surface and the incident angle of the reflected light from the surface to the first reflecting surface, thereby helping to change the image distance formed from the light emitted from the optical expansion waveguide in combination with the first reflecting surface using a curved surface or the second reflecting surface using a curved surface.

[0050] In this embodiment, there is no specific limitation on the shape of the curved surface or the size of the curved surface area included in any of the first set of opposing surfaces, as long as the emission angle of the light emitted by the optical expansion waveguide is changed and the image distance formed from the light emitted by the optical expansion waveguide meets a predetermined requirement. The curved surface included in any of the first set of opposing surfaces may be a curved surface having a certain curvature or a free-form surface. Preferably, the curved surface included in any of the first set of opposing surfaces diverges or focuses the reflected light from the surface.

[0051] For illustration, as shown in FIG. 5, FIG. 5 is a schematic diagram of light propagation on one surface of the first set of opposing surfaces and the first reflecting surface in one embodiment. As shown in the drawing, surface 100 is one surface of the first set of opposing surfaces of the first waveguide base 1, and surface 100 is a curved surface (its reference plane is surface 103). The reflected light rays L3, L4 of the incident light rays L3 and L4 on surface 100 become divergent, and the reflected light rays L3', L4' after the light rays are reflected by the first reflecting surface 101 become divergent. As a result, the image distance formed from the light emitted by the optical expansion waveguide is reduced.

[0052] Preferably, the optically enhanced waveguide includes a second waveguide base, the second reflective surface array is disposed within the second waveguide base, the second waveguide base includes at least a third set of opposing surfaces, and the light entering the second waveguide base is reflected by each of the third set of opposing surfaces and propagates forward. Specifically, the total reflection condition is satisfied when the light is incident on each of the third set of opposing surfaces. The third set of opposing surfaces may or may not be parallel to each other, and the light may be reflected by each of the third set of opposing surfaces and propagates forward.

[0053] Preferably, each of the second reflecting surfaces forms an inclination angle with respect to any of the surfaces of the third set of opposing surfaces. The inclination angle of the second reflecting surface with respect to a surface refers to the chord of the second reflecting surface and the surface being neither parallel nor perpendicular. Correspondingly, the inclination angle formed by the second reflecting surface with respect to a surface is the included angle between the chord of the second reflecting surface and the surface, and if the surface is a curved surface, the inclination angle formed by the second reflecting surface with respect to the surface is the included angle between the chord of the second reflecting surface and the chord of the surface. When the light propagated through the second waveguide base is incident on the second reflecting surface, a part of the light energy is transmitted through the second reflecting surface and continues to propagate, and another part of the light energy is reflected and emitted out of the second waveguide base, forming the output light of the optical expansion waveguide.

[0054] 3-1, 3-2 and 6 are combined for illustration, and FIG. 6 is a schematic diagram of light propagation in the second waveguide base in one embodiment. As shown in the drawing, the light coupled from the first waveguide base 1 to the second waveguide base 2 is reflected by the surfaces 2-A and 2-B of the second waveguide base 2 and propagates forward. During the propagation, when the light meets the second reflecting surface 201, it reflects a part of the light energy at a certain energy ratio, so that a part of the light is emitted out of the second waveguide base 2.

[0055] In this embodiment, the magnitude of the inclination angle formed by each second reflecting surface with respect to any of the opposing surfaces of the third set is not limited, as long as the light propagating in the second waveguide base is reflected and emitted out of the second waveguide base when the light is incident on the second reflecting surface. In practical application, the expansion requirement of the light in the second dimension may be set according to the size of the first waveguide base and the size of the second waveguide base.

[0056] As an example, see FIG. 7, which is a schematic diagram of the light rays in the second waveguide base propagating to form a corresponding effective light passing aperture in one embodiment, the light propagating through the second waveguide base 2 is reflected when it meets each of the second reflecting surfaces S1, S2, S3, S4 and S5 respectively, and causes at least a part of the light to exit the second waveguide base 2. The total projection surface S of each of the second reflecting surfaces S1, S2, S3, S4 and S5 on the surface 2-A determines the effective light passing aperture of the optical extension waveguide. For the optical display device, the effective light passing aperture of the optical extension waveguide must ensure that the image from the image source is fully expanded, that is, the image formed by the output light of the optical extension waveguide contains the complete information of the image in the first dimension and the second dimension.

[0057] Preferably, the inclination angle formed by the second reflecting surface with respect to one of the surfaces of the third set as the coupling output surface is greater than 0° and less than 45°, and is indicated as 0°<β≦45°, and when the second reflecting surface rotates along a counterclockwise direction with respect to one of the surfaces, the inclination angle formed by the second reflecting surface with respect to the surface is positive. With respect to one of the surfaces of the third set as the coupling output surface, the light reflected by the second reflecting surface is emitted out of the second waveguide base through the surface. In this way, the light is expanded by the second reflecting surface, and the thickness of the second waveguide base can be reduced, and the entire waveguide becomes thinner and lighter.

[0058] In one preferred embodiment, at least one of the opposing surfaces of the third set is curved at least locally to change the incident angle of the reflected light from the surface to the second reflecting surface, thereby helping to realize that the image distance formed from the light emitted from the optical expansion waveguide meets a predetermined requirement. At least one of the opposing surfaces of the third set is curved at least locally to change the reflection angle of the light after passing through the surface, and change the incident angle of the reflected light from the surface to the second reflecting surface, thereby realizing the change of the image distance formed from the light emitted from the optical expansion waveguide in combination with the first reflecting surface using a curved surface or the second reflecting surface using a curved surface.

[0059] In this embodiment, there is no specific limitation on the shape of the curved surface or the size of the curved surface area included in any of the opposing surfaces of the third set, as long as the emission angle of the light emitted by the optical expansion waveguide is changed and the image distance formed from the light emitted by the optical expansion waveguide meets a predetermined requirement. The curved surface included in any of the opposing surfaces of the third set may be a curved surface having a certain curvature or a free-form surface. Preferably, the curved surface included in any of the opposing surfaces of the third set diverges or focuses the reflected light of the surface.

[0060] In optical design, in order to ensure that the resolution, contrast or clarity of the generated image meets the requirements, if a curved surface is used for the first reflecting surface of the first waveguide base and at least one surface of the first set of opposing surfaces, the curved surface parameters of the first reflecting surface of the first waveguide base and any surface of the first set of opposing surfaces should satisfy a certain relationship. If a curved surface is used for the second reflecting surface of the second waveguide base and at least one surface of the third set of opposing surfaces, the curved surface parameters of the second reflecting surface of the second waveguide base and any surface of the third set of opposing surfaces should satisfy a certain relationship. With reference to FIG. 8 in combination, FIG. 8 is a schematic diagram of a reflecting surface using a curved surface and structural parameters of a surface of any waveguide base in one embodiment. The optical design is performed based on a collimated main axis beam emitted from an object point on the axis, and when the main axis beam is perpendicularly incident on the coupling input surface of the waveguide base, the corresponding relationships of each parameter are as follows: αR2=α R1 -β o ; αR1=π / 2-β i ; β i is the included angle between the coupling input plane and the horizontal reference plane of the waveguide base surface, and β o is the angle between the plane on which the chord of the curved reflecting surface is located and the horizontal reference plane of the waveguide base surface, and α R1 is the angle between the principal axis ray and the horizontal reference plane normal of the waveguide base surface, and α R2 is the included angle between the principal axis ray and the reference surface normal of the coupling output surface.

[0061] h s =h r =N*(λ / 2); H r =H / (sin(β o )); H s =H / (tan(β o )); h s is the local curvature height of the curved waveguide corresponding to a single reflecting surface, and H s is the local chord length of the curved waveguide corresponding to a single reflecting surface, and h ris the local curved arrow height corresponding to the curved reflecting surface itself, and H r is the local chord length corresponding to the curved reflecting surface itself; N is the number of apertures according to the image distance adjustment needs; λ is the reference wavelength selected during optical design. Based on the specific image distance adjustment needs, the required local curvature of the curved reflecting surface and the local curvature radius of the waveguide-based curved surface can be obtained by calculating according to the corresponding arrow height and chord length.

[0062] For illustration, refer to Figures 9-1 and 9-2, which are schematic diagrams of using a curved surface for any of the opposing surfaces of any of the waveguide bases in this embodiment, and as shown in the drawings, any of the opposing surfaces of the waveguide base may be a free-form surface, a concave surface or a convex surface.

[0063] Furthermore, the first waveguide base further includes a first coupling output surface that causes the reflected light of the first reflecting surface to radiate outside the first waveguide base, and the second waveguide base further includes a second coupling input surface that causes the light emitted by the first waveguide base to enter the second waveguide base, and the first coupling output surface and the second coupling input surface are optically coaxial. The first coupling output surface and the second coupling input surface being optically coaxial means that the first coupling output surface and the second coupling input surface are parallel to each other corresponding to a local portion of the optical axis.

[0064] In this embodiment, the shape of the first coupling output surface of the first waveguide base and the shape of the second coupling input surface of the second waveguide base are not limited, as long as the first coupling output surface and the second coupling input surface are optically coaxial. The first coupling output surface may be, but is not limited to, a flat surface, an inclined surface, a sawtooth surface, or a curved surface. The second coupling input surface may be, but is not limited to, a flat surface, an inclined surface, a sawtooth surface, or a curved surface. As an example, refer to Fig. 10-1 to Fig. 10-4, and Fig. 10-1 to Fig. 10-4 are four embodiments of the first coupling output surface of the first waveguide base and the second coupling input surface of the second waveguide base in this embodiment, respectively.

[0065] In this embodiment, the relative positions of the first and second waveguide bases are not limited, and the light coupled out from the first waveguide base may be made to enter the second waveguide base. As an example, refer to Fig. 11-1 to Fig. 11-3, which respectively show three embodiments of the arrangement positions of the first and second waveguide bases in this embodiment, and as shown in the drawings, the first waveguide base 1 is provided in front of, behind, or above the second waveguide base 2.

[0066] The optical display device of this embodiment may be a near-eye display device, for example a head-mounted device, which can change the focused image distance, is suitable for users with visual impairments, has a thin and light structure, and improves the user's comfort and perception experience.

[0067] The above is a detailed introduction of the optical display device provided by the present invention. In this specification, specific examples are used to describe the principle and embodiment of the present invention, and the description of the above examples is merely used to understand the method and spirit of the present invention. Here, those skilled in the art may make some improvements and modifications to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. An optical display device, comprising: an image generating device; a coupling device; and an optical expansion waveguide, the coupling device being configured to couple light output from the image generating device to the optical expansion waveguide in correspondence with the image generating device; The optical expansion waveguide includes at least a first reflective surface array and a second reflective surface array, and the light entering the optical expansion waveguide passes through the first reflective surface array and the second reflective surface array in order, and the first reflective surface array and the second reflective surface array each expand the light propagated through the optical expansion waveguide in a one-dimensional direction, and realize the expansion of the light entering the optical expansion waveguide in a two-dimensional direction, and emit the light out of the optical expansion waveguide to form an image; An optical display device characterized in that at least one of the first reflective surface of the first reflective surface array and the second reflective surface of the second reflective surface array is curved at least locally, so that the image distance formed from the light emitted by the optical expansion waveguide satisfies a specified requirement.

2. At least a portion of a first reflecting surface of the first reflecting surface array is curved, and the first reflecting surface diverges light reflected by the first reflecting surface; The optical display device according to claim 1, characterized in that at least a portion of the second reflective surface of the second reflective surface array is curved, and the second reflective surface disperses the light reflected by the second reflective surface.

3. 2. The optical display device of claim 1, wherein the first reflective surface array expands the light propagated through the optical expansion waveguide in a first dimensional direction, and each of the first reflective surfaces forms an inclination angle with respect to the first dimensional direction.

4. 2. The optical display device of claim 1, wherein the optically expanded waveguide includes a first waveguide base, the first reflective surface array is disposed within the first waveguide base, the first waveguide base includes at least a first set of opposing surfaces, and light entering the first waveguide base is reflected by each of the first set of opposing surfaces and propagates forward.

5. The optical display device according to claim 4, characterized in that at least a portion of at least one of the first set of opposing surfaces is curved, thereby changing the angle at which the reflected light from that surface enters the first reflecting surface, thereby helping to ensure that the image distance formed from the light emitted by the optical expansion waveguide meets a specified requirement.

6. 6. The optical display device of claim 5, wherein at least one surface of the first set of opposing surfaces diverges light reflected therefrom.

7. 2. The optical display device of claim 1, wherein the optically expanded waveguide includes a second waveguide base, the second reflective surface array is disposed within the second waveguide base, the second waveguide base includes at least a third set of opposing surfaces, and light entering the second waveguide base is reflected by each of the third set of opposing surfaces and propagates forward.

8. 8. The optical display device according to claim 7, wherein each of the second reflecting surfaces forms an inclination angle with respect to one of the opposing surfaces of the third set.

9. 9. The optical display device according to claim 8, wherein the inclination angle formed by the second reflecting surface with respect to one surface of the third set of opposing surfaces as a coupling output surface is greater than 0° and less than 45°, and when the second reflecting surface rotates in a counterclockwise direction with respect to the one surface, the inclination angle formed by the second reflecting surface with respect to the surface is positive.

10. The optical display device according to claim 7, characterized in that at least one surface of the third set of opposing surfaces is curved at least locally, thereby changing the angle at which the reflected light from that surface enters the second reflecting surface, thereby helping to ensure that the image distance formed from the light emitted by the optical expansion waveguide meets a specified requirement.

11. 11. The optical display of claim 10, wherein at least one surface of the third set of facing surfaces diverges light reflected by that surface.

12. The optically expanded waveguide includes a first waveguide base and a second waveguide base, the first reflective surface array is disposed within the first waveguide base, and the second reflective surface array is disposed within the second waveguide base; 2. The optical display device according to claim 1, wherein the first waveguide base further includes a first coupling output surface that causes the reflected light of the first reflecting surface to be radiated outside the first waveguide base, and the second waveguide base further includes a second coupling input surface that causes the light emitted from the first waveguide base to enter the second waveguide base, and the first coupling output surface and the second coupling input surface are optically coaxial.

13. The optical display device according to any one of claims 1 to 12, characterized in that the coupling device divides the light output from the image generating device into a first beam and a second beam having different polarization states, and couples and inputs the first beam and the second beam into the optical extension waveguide, respectively.

14. 14. The optical display device of claim 13, wherein the combining device includes a polarization splitting unit, a light conversion unit, a collimating unit, and a light selection unit, the polarization splitting unit performs polarization splitting on the light output from the image generating device, the light conversion unit realizes mutual conversion of two lights having different polarization states, the collimating unit collimates the light to uniformly distribute the light energy, and the light selection unit inputs the light corresponding to the polarization state of the light that has passed through the light selection unit into the optical extension waveguide.

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