Light leakage prevention waveguide device

Abstract

The invention provides a waveguide device capable of preventing light leakage. The waveguide device comprises an optical waveguide and an optical machine, the optical waveguide comprises a waveguide substrate, a coupling-in grating and a coupling-out grating which are arranged on the waveguide substrate, and an angle selective transmission film which is arranged on the waveguide substrate opposite to the coupling-out grating; after virtual image light emitted by an optical machine is coupled into the waveguide substrate through the coupling-in grating, leakage light which is diffracted by the coupling-out grating and is coupled out by deviating from human eyes is incident to the angle selection transmission film. A first included angle range between real light in the target view field range and the horizontal direction is matched with a selective transmission angle range of the angle selective transmission film, so that the real light in the target view field range enters human eyes after passing through the angle selective transmission film; moreover, the optical waveguide and the optical machine are arranged in an inclined manner, so that a second included angle range between the leakage light and the horizontal direction is not intersected with the first included angle range. According to the scheme, the problem of light beam leakage of the optical waveguide is solved, and the impression of a user to the real world is ensured.

Description

Technical Field

[0001] The present invention relates to the field of optical waveguides, and particularly to an optical waveguide device for preventing light leakage. Background Art

[0002] Due to the grating diffraction characteristics of diffractive optical waveguides, there will be "light leakage" equivalent to the brightness of the main image, resulting in privacy leakage problems in use. Therefore, how to avoid the light leakage problem of diffractive optical waveguides has become a key technical problem to be solved by those skilled in the art. Summary of the Invention

[0003] The present invention provides an optical waveguide device for preventing light leakage to solve the problem of light leakage of the optical waveguide in an AR near-eye display device.

[0004] According to a first aspect of the present invention, there is provided an optical waveguide device for preventing light leakage, comprising:

[0005] An optical waveguide and an optical engine; the optical waveguide includes a waveguide substrate, a coupling grating and a coupling-out grating disposed on the waveguide substrate, and an angle-selective transmission film disposed opposite to the coupling-out grating on the waveguide substrate; after the virtual image light rays emitted by the optical engine are coupled into the waveguide substrate through the coupling grating, the leakage light rays diffracted by the coupling-out grating and departing from the human eye are incident on the angle-selective transmission film;

[0006] Wherein, a first angle range between the real light rays in the target field of view range and the horizontal direction matches the selective transmission angle range of the angle-selective transmission film, so that the real light rays in the target field of view range enter the human eye after passing through the angle-selective transmission film; and, the optical waveguide and the optical engine are inclined, so that a second angle range between the leakage light rays and the horizontal direction has no intersection with the first angle range.

[0007] Optionally, the optical waveguide and the optical engine are arranged such that: the inclination angle of the optical waveguide deviating from the vertical direction is a first angle; the inclination angle of the optical engine deviating from the normal direction of the optical waveguide is a second angle; the target field of view range includes the field of view above the horizontal direction and the field of view below the horizontal direction; the first angle and the second angle are configured such that when the directions of the leakage light rays are all below the horizontal direction, the minimum angle value in the second angle range is greater than or equal to the maximum angle value below the horizontal direction in the first angle range, and when the directions of the leakage light rays are all above the horizontal direction, the minimum angle value in the second angle range is greater than or equal to the maximum angle value above the horizontal direction in the first angle range.

[0008] Optionally, the range of the first included angle is: the angular range formed by the included angle between the lines connecting the two boundaries of the output grating in the direction of the line connecting the output grating and the input grating and the human eye and the horizontal direction.

[0009] Optionally, the optical waveguide deviates from the vertical direction in the counterclockwise direction, and the optical engine deviates from the normal direction of the optical waveguide in the counterclockwise direction.

[0010] The minimum angle value within the range of the second included angle being greater than or equal to the maximum angle value below the horizontal direction within the range of the first included angle is:

[0011] θ1 = γ + β - θ / 2 ≥ α1; where γ is the first angle, β is the second angle, θ is the interval size of the range of the second included angle, θ1 is the minimum angle value within the range of the second included angle, and α1 is the maximum angle value below the horizontal direction within the range of the first included angle.

[0012] Optionally, the optical waveguide deviates from the vertical direction in the clockwise direction, and the optical engine deviates from the normal direction of the optical waveguide in the clockwise direction.

[0013] Optionally, the minimum angle value within the range of the second included angle being greater than or equal to the maximum angle value above the horizontal direction within the range of the first included angle is: θ1 = γ + β - θ / 2 ≥ α2; where γ is the first angle, β is the second angle, θ is the interval size of the range of the second included angle, θ1 is the minimum angle value within the range of the second included angle, and α2 is the maximum angle value above the horizontal direction within the range of the first included angle.

[0014] Optionally, the angle-selective transmissive film is used to absorb the leaked light or reflect it back to the waveguide substrate for continued propagation.

[0015] A light leakage prevention waveguide device provided by the present invention includes an angle-selective transmission film disposed on the other side of the output grating relative to the waveguide substrate. Therefore, when the virtual image light rays emitted by the optical engine are coupled into the waveguide substrate through the input grating, the leakage light rays diffracted by the output grating and deviating from the human eye are incident on the angle-selective transmission film. At the same time, the range of the first included angle between the real light rays in the target field of view and the horizontal direction matches the range of the selective transmission angle of the angle-selective transmission film, so that the real light rays in the target field of view enter the human eye after passing through the angle-selective transmission film, avoiding the influence of the angle-selective transmission film on the user's perception of the real world. On the premise of the above, the technical solution provided by the present invention also cleverly obliquely arranges the optical waveguide and the optical engine so that the range of the second included angle between the leakage light rays and the horizontal direction has no intersection with the range of the first included angle and avoids each other. Thus, the filtering effect of the angle-selective transmission film on the leakage light rays and the transmission effect on the real light rays in the target field of view in the real world do not conflict with each other. It will neither inevitably filter out the real light rays in the target field of view due to filtering the leakage light rays, affecting the user's perception of the real world, nor miss the leakage light rays because it is necessary to transmit the real light rays in the target field of view, resulting in partial leakage of user privacy. It can be seen that the technical solution provided by the present invention solves the problem of light beam leakage of the optical waveguide while ensuring the user's perception of the real world, thus achieving the effect of protecting user privacy and ensuring the user's perception of the real world.

[0016] Further, when the optical waveguide and the optical engine are arranged such that the optical waveguide is offset counterclockwise, this structure fully considers the actual needs of users, is more suitable for the glasses structure, and conforms to ergonomics. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0018] Figure 1 is a traditional waveguide device;

[0019] Figure 2 is a light leakage prevention waveguide device provided by a typical embodiment of the present invention;

[0020] Figure 3 is a light leakage prevention waveguide device provided by another typical embodiment of the present invention;

[0021] Description of the reference numerals:

[0022] 101 - Optical engine;

[0023] 102 - Coupling-in grating;

[0024] 103 - Waveguide substrate;

[0025] 104 - Coupling-out grating;

[0026] 105 - Coupling-out light ray;

[0027] 106 - Human eye;

[0028] 107 - Leaked light ray;

[0029] 108 - Light ray of the real world;

[0030] 201 - Coupling-out light ray;

[0031] 202 - Normal line of the optical waveguide

[0032] 203 - Real light ray;

[0033] 204 - Leaked light ray;

[0034] 205 - Angle-selective transmission film;

[0035] 206 - Human eye;

[0036] 207 - Coupling-in grating;

[0037] 208 - Waveguide substrate;

[0038] 209 - Coupling-out grating;

[0039] 210 - Optical engine. Detailed implementation manners

[0040] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0041] The terms "first", "second", "third", "fourth", etc. (if any) in the description, claims and the above-mentioned drawings of the present invention are used to distinguish similar objects and do not necessarily describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0042] Light is incident on the coupling grating 102, and the angle between the central field-of-view light ray and the normal line of the diffractive optical waveguide (as shown by the dashed line part in Figure 1 the figure) is θ. The light is totally internally reflected and transmitted in the diffractive optical waveguide, and then is coupled out into the human eye 106 through the coupling-out grating 104. The angle between the central field-of-view light ray of the human eye 106 and the waveguide normal line (as shown by the dashed line part in the figure) is also θ. Since the grating has both reflection orders and transmission orders, there is always a leakage-coupled light ray 107 on the other side of the normal coupled-out light ray 105 with respect to the diffractive optical waveguide. These two light rays are always mirror-symmetrical along the waveguide plane of the diffractive optical waveguide. Due to the existence of the leakage-coupled light ray 107, the other side of the human eye 106 with respect to the diffractive optical waveguide can also see the image displayed by the optical engine, resulting in a great risk of privacy leakage.

[0043] At the same time, in the AR near-eye display device, the human eye 106 not only needs to see the normal coupled-out light ray 105, but also needs to see the light ray 108 of the real world through the diffractive optical waveguide. Therefore, the problem of light leakage cannot be solved by blocking the light ray 107.

[0044] In view of this, the inventors of the present application creatively propose: a light leakage prevention device, by obliquely arranging the diffractive optical waveguide and the optical engine, and by designing the relationship between the waveguide tilt angle, the optical engine tilt angle, and the optical engine field of view, so that the angular range of seeing the light ray of the real world through the coupling-out grating area has no intersection with the angular range of the leakage light ray. The transmission angle interval of the angle-selective film layer is set as the angular range of seeing the light ray of the real world through the coupling-out grating area. Furthermore, the angular range of seeing the light ray of the real world through the coupling-out grating area falls within the transmission angle interval of the angle-selective film layer, while the angular range of the leakage light ray is not within the transmission angle interval of the angle-selective film layer, thereby solving the problem of light leakage without affecting the viewing effect of the real world.

[0045] The technical solution of the present invention is described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0046] Please refer to Figure 2 or Figure 3 , among which, in Figure 2 Figure 3 The leakage light 204 is shown in the figure only for the convenience and clarity of description. In practice, when the angle selective transmission film 205 provided by the present invention is provided, the leakage light 204 is actually absorbed or reflected back to the optical waveguide instead of leaking to the outside world. The horizontal direction, vertical direction, normal line and other reference lines mentioned below can all be referenced. Figure 2 or Figure 3 According to one embodiment of the present invention, a waveguide device for preventing light leakage is provided, comprising:

[0047] The optical waveguide and the optical machine 210; the optical waveguide includes a waveguide substrate 208, an in-coupling grating 207 and an out-coupling grating 209 disposed on the waveguide substrate 208, and an angle selective transmission film 205 disposed on the out-coupling grating 209 relative to the waveguide substrate 208; the virtual image light emitted by the optical machine 210 is coupled into the waveguide substrate 208 via the in-coupling grating 207, and the leakage light coupled away from the human eye 206 is diffracted by the out-coupling grating 209 and incident on the angle selective transmission film 205; and the effective light coupled toward the human eye 206 by the out-coupling grating 209 is diffracted and enters the human eye. The real light 203 enters the human eye after passing through the angle selective transmission film 205 and the out-coupling grating 209 in sequence.

[0048] Among them, the angle-selective transmission film 205 has angle selectivity and has different transmittances for light incident thereon at different angles. The human eye's field of view usually has a certain range. In this application, the target field of view range at least includes the field of view range for the human eye to achieve basic viewing of the real world. The angle range of the leakage light is related to the relative position between the optical machine, the waveguide and the human eye. This application selects the transmission angle range of the angle-selective transmission film to match the angle range of the real light, so as to have better transmittance to the real light and not affect the user's viewing of the real world. At the same time, it cooperates with the design of the optical machine, the waveguide and the position of the human eye, so that the angle range of the leakage grating has no intersection with the angle range of the real light, that is, it is staggered with the transmission angle range of the angle-selective transmission film, so as to transmit less or even no leakage light and avoid the leakage of virtual graphic light.

[0049] In one embodiment, the angle selective transmission film 205 is used to absorb or reflect the leaked light back to the waveguide substrate 208 for continued propagation, which can solve the problem of customer privacy leakage.

[0050] In a specific example, the angle-selective transmissive film 205 is a privacy screen film.

[0051] In a more preferred embodiment, when the angle-selective transmissive film 205 is used to reflect the leaked light 204 back into the optical waveguide for re-propagation and then coupled out from the output grating 209 and into the human eye 206, while avoiding the leakage of user privacy, the waveguide efficiency is also improved.

[0052] Generally, the target field of view range includes the field of view within a certain angle above the horizontal direction and the field of view within a certain angle below the horizontal direction.

[0053] In one embodiment, the optical waveguide is inclined with respect to the optical engine 210 such that the directions of the leaked light are all below the horizontal direction.

[0054] In another embodiment, the optical waveguide is inclined with respect to the optical engine 210 such that the directions of the leaked light are all above the horizontal direction.

[0055] In summary, the technical solution provided by the present invention solves the problem of light beam leakage in the optical waveguide while ensuring the user's perception of the real world; thus achieving the effects of protecting user privacy and ensuring the user's perception of the real world. In one embodiment, the optical waveguide and the optical engine 210 are arranged such that the inclination angle of the optical waveguide deviating from the vertical direction is the first angle; the inclination angle of the optical engine 210 deviating from the normal line 202 direction of the optical waveguide is the second angle.

[0056] Among them, in one embodiment, the first angle and the second angle are configured such that when the directions of the leaked light are all below the horizontal direction, the minimum angle value within the second included angle range is greater than or equal to the maximum angle value below the horizontal direction within the first included angle range. The first included angle range is the angle range formed by the angles between the connections of the two boundaries of the output grating 209 in the direction of the connection line between the output grating 209 and the input grating 207 and the human eye 206 and the horizontal direction. In one embodiment, the angle between the central field of view light of the leaked light and the horizontal direction is the sum of the first angle and the second angle, and the interval size of the second included angle range is the same as the interval size of the virtual image field of view.

[0057] As Figure 2 shown, in a specific embodiment, the optical waveguide deviates from the vertical direction in the counterclockwise direction, and the optical engine 210 deviates from the normal line 202 direction of the optical waveguide in the counterclockwise direction.

[0058] Among them, in one embodiment, the fact that the minimum angle value within the second included angle range is greater than or equal to the maximum angle value below the horizontal direction within the first included angle range specifically includes:

[0059] θ1 = γ + β - θ / 2 ≥ α1; where γ is the first angle, β is the second angle, θ is the interval size of the second included angle range, θ1 is the minimum angle value within the second included angle range, and α1 is the maximum angle value below the horizontal direction within the first included angle range.

[0060] Since generally for the 206-degree field of view of the human eye, when α2 is greater than α1, it is required that γ + β + θ / 2 is greater than α2, then the tilt angle γ will be very large. Among them, in the technical solution provided by this specific embodiment, since the light wave guide deviates counterclockwise, it is more suitable for the glasses structure and conforms to ergonomics.

[0061] In another embodiment, the first angle and the second angle are configured such that: when the directions of the leaked light are all above the horizontal direction, the minimum angle value within the second included angle range is greater than or equal to the maximum angle value above the horizontal direction within the first included angle range.

[0062] As Figure 3 shown, in another embodiment, the optical waveguide deviates clockwise from the vertical direction, and the optical engine 210 deviates clockwise from the normal direction 202 of the optical waveguide.

[0063] Among them, in one embodiment, the minimum angle value within the second included angle range being greater than or equal to the maximum angle value above the horizontal direction within the first included angle range is: θ1 = γ + β - θ / 2 ≥ α2; where γ is the first angle, β is the second angle, θ is the interval size of the second included angle range, θ1 is the minimum angle value within the second included angle range, and α2 is the maximum angle value above the horizontal direction within the first included angle range.

[0064] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A light-leakage-proof waveguide device, characterized in that, Comprising: An optical waveguide and an optical engine; the optical waveguide includes a waveguide substrate, an input grating and an output grating disposed on the waveguide substrate, and an angle-selective transmission film disposed opposite to the output grating on the waveguide substrate; after the virtual image light rays emitted by the optical engine are coupled into the waveguide substrate through the input grating, the leakage light rays diffracted by the output grating and coupled out away from the human eye are incident on the angle-selective transmission film. Wherein, the range of the first included angle between the real light rays in the target field of view and the horizontal direction matches the range of the selective transmission angle of the angle-selective transmission film, so that the real light rays in the target field of view enter the human eye after passing through the angle-selective transmission film; and, the optical waveguide and the optical engine are inclined, so that the range of the second included angle between the leakage light rays and the horizontal direction has no intersection with the range of the first included angle.

2. The light leakage-proof waveguide device according to claim 1, wherein The optical waveguide and the optical engine are configured such that: the inclination angle of the optical waveguide deviating from the vertical direction is a first angle; the inclination angle of the optical engine deviating from the normal direction of the optical waveguide is a second angle; the target field of view includes the field of view above the horizontal direction and the field of view below the horizontal direction; the first angle and the second angle are configured such that when the directions of the leakage light rays are all below the horizontal direction, the minimum angle value in the range of the second included angle is greater than or equal to the maximum angle value below the horizontal direction in the range of the first included angle, and when the directions of the leakage light rays are all above the horizontal direction, the minimum angle value in the range of the second included angle is greater than or equal to the maximum angle value above the horizontal direction in the range of the first included angle.

3. The leak-light-proof waveguide device according to claim 2, wherein The range of the first included angle is: the angular interval formed by the included angles between the connections of the two boundaries of the output grating in the direction of the connection line between the output grating and the input grating and the human eye and the horizontal direction.

4. The leak-proof waveguide device according to claim 2, wherein, The optical waveguide deviates from the vertical direction in the counterclockwise direction, and the optical engine deviates from the normal direction of the optical waveguide in the counterclockwise direction.

5. The leak-proof waveguide device according to claim 4, characterized in that, The minimum angle value in the range of the second included angle being greater than or equal to the maximum angle value below the horizontal direction in the range of the first included angle is: θ1 = γ + β - θ / 2 ≥ α1; where γ is the first angle, β is the second angle, θ is the interval size of the range of the second included angle, θ1 is the minimum angle value in the range of the second included angle, and α1 is the maximum angle value below the horizontal direction in the range of the first included angle.

6. The leak - light - proof waveguide device according to claim 2, characterized in that, The optical waveguide deviates from the vertical direction in the clockwise direction, and the optical engine deviates from the normal direction of the optical waveguide in the clockwise direction.

7. The light leakage-proof waveguide device according to claim 6, characterized in that, The minimum angle value in the range of the second included angle being greater than or equal to the maximum angle value above the horizontal direction in the range of the first included angle is: θ1 = γ + β - θ / 2 ≥ α2; where γ is the first angle, β is the second angle, θ is the interval size of the range of the second included angle, θ1 is the minimum angle value in the range of the second included angle, and α2 is the maximum angle value above the horizontal direction in the range of the first included angle.

8. The light-leakage-proof waveguide device according to claim 1, wherein The angle-selective transmission film is used to absorb or reflect the leakage light rays back to the waveguide substrate for continued propagation.

Images