An optical waveguide

Abstract

The utility model discloses an optical waveguide, including optical waveguide main part and grating, the optical waveguide main part vertical arrangement, grating sets up on the optical waveguide main part, grating from the one end close to human eye to the one end away from human eye is set down to the inclination. The utility model can alleviate AR glasses's dispersion and ghost phenomenon, limit the electronic display device light of human eye below in the real scene and enter human eye, improve visual definition.

Description

Technical Field

[0001] This utility model belongs to the field of AR glasses technology, specifically relating to an optical waveguide. Background Technology

[0002] Augmented reality glasses, also known as AR glasses, are a new type of human-computer interaction device that is gradually being applied in various scenarios such as gaming and entertainment, remote collaboration, industrial inspection, and medical assistance. When using AR glasses, users often need to simultaneously observe the real-world scene and the content displayed on electronic display devices (such as smartphones and tablets). In this composite visual environment, light from the electronic display device enters the optical system of the AR glasses, especially the waveguide structure.

[0003] Currently, AR glasses commonly employ a combination of optical waveguides and grating structures to achieve image coupling and extraction. The grating primarily functions to guide light from the outside into the waveguide and to guide light from the waveguide to the human eye. However, due to the wavelength selectivity of the grating, processing complex spectra emitted from external display sources (such as mobile phones) often leads to the following problems: The dispersion phenomenon is obvious: light of different wavelengths propagates in different directions after being reflected or diffracted by the grating, which ultimately results in color shift and blurring in the user's eyes; Image ghosting: Light rays from the same display source undergo multiple reflections and waveguide couplings, resulting in a ghosting effect on the imaging plane. Unintended interference: When a user is in a perspective where AR and reality are integrated, light from some real-world scenes (such as the phone below) may enter the waveguide and be reflected and diffracted before appearing in front of the user's eyes instead of being directly transmitted. This interferes with the normal display of AR images and affects visual clarity. As shown in Figure 1 of the prior art, external electronic display devices such as mobile phones are usually below the AR device, i.e., below the user's eyes. When the light shines on the grating, due to a reflection from the grating's inclined surface, the light will couple into the optical waveguide for reflection and diffraction. Ultimately, this causes some of the light from the electronic display device to produce chromatic aberration and ghosting below the user's eyes, thus affecting the AR device experience. Therefore, in order to avoid the shortcomings of the prior art, it is necessary to improve the existing technology. Utility Model Content

[0004] The purpose of this invention is to provide an optical waveguide that can reduce the dispersion and ghosting phenomena of AR glasses, limit the light from electronic display devices below the human eye in real-world scenarios from entering the human eye, and improve visual clarity.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: An optical waveguide includes an optical waveguide body, a coupling grating, and a coupling grating. The coupling grating and the coupling grating are disposed on the optical waveguide body. The coupling grating is used to couple an image beam emitted by an optomechanical system into the optical waveguide body, and the coupling grating is used to couple the image beam out of the optical waveguide body and into a human eye. The coupling grating is inclined downward from the end closer to the human eye to the end farther away from the human eye.

[0006] As a preferred embodiment of the aforementioned optical waveguide, the coupling grating is disposed on the side of the optical waveguide body closer to the human eye, and the coupling grating is inclined upward from the optical waveguide body.

[0007] As a preferred embodiment of the aforementioned optical waveguide, the coupling grating is disposed on the side of the optical waveguide body away from the human eye, and the coupling grating is inclined downward from the optical waveguide body.

[0008] As a preferred embodiment of the aforementioned optical waveguide, the angle between the coupling grating and the main body of the optical waveguide is 15 to 60 degrees.

[0009] As a preferred embodiment of the aforementioned optical waveguide, the duty cycle of the coupling grating is gradually varied.

[0010] As a preferred embodiment of the aforementioned optical waveguide, the duty cycle of the coupling grating gradually increases from top to bottom.

[0011] As a preferred embodiment of the aforementioned optical waveguide, the duty cycle of the coupling grating gradually decreases from top to bottom.

[0012] As a preferred embodiment of the aforementioned optical waveguide, the angle between the coupling grating and the main body of the optical waveguide is 25 to 45 degrees.

[0013] As a preferred embodiment of the aforementioned optical waveguide, the angle between the coupling grating and the main body of the optical waveguide is 25 degrees.

[0014] As a preferred embodiment of the aforementioned optical waveguide, the angle between the coupling grating and the main body of the optical waveguide is 45 degrees.

[0015] As a preferred embodiment of the aforementioned optical waveguide, an optical engine is provided on the optical waveguide body, and the light beam emitted by the optical engine is coupled into the optical waveguide body and coupled out to the human eye through the optical waveguide body.

[0016] The advantages of implementing the optical waveguide provided by this utility model compared with the prior art are as follows: The coupling grating of this invention is disposed on the optical waveguide body, and the coupling grating is tilted downward from the end closer to the human eye to the end farther away from the human eye. This tilting direction of the coupling grating is parallel or nearly parallel to the light from the electronic device located below the human eye, thereby effectively reducing the interference light generated by the electronic device located below the human eye from being reflected or diffracted into the human eye, which ultimately leads to obvious dispersion or ghosting phenomena in vision. The downward tilting of the coupling grating from the end closer to the human eye to the end farther away from the human eye makes it difficult for some interference light to be effectively coupled into the optical waveguide body, and even if it enters the optical waveguide body, it cannot be normally emitted to the human eye. Thus, optical shielding of some interference light is achieved in the physical path. Without changing the overall structure of the optical waveguide body, this invention avoids the path of interference light entering the vision at the structural level, and essentially achieves root control of dispersion and ghosting problems. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings of the embodiments will be briefly described below.

[0018] Figure 1 is a schematic diagram of the prior art; Figure 2 is a schematic diagram of this utility model; Figure 3 is a schematic diagram of the coupling grating of this utility model being disposed on the optical waveguide body on a different side from the human eye; Figure 4 is a schematic diagram of the coupling grating of this utility model being disposed on the optical waveguide body on the same side as the human eye; Figure 5 is a schematic diagram showing that the duty cycle of the coupling grating of this utility model gradually increases from top to bottom; Figure 6 is a schematic diagram showing that the duty cycle of the coupling grating of this utility model gradually decreases from top to bottom.

[0019] Marked in the image: 100, Coupling grating; 200, Optical waveguide body; 300, Electronic equipment; 400, Optomechanic. Detailed Implementation

[0020] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0021] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0022] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If "first" or "second" is used in the description, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0023] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0024] Please refer to Figures 1 to 6 together. The optical waveguide provided in the embodiment of this utility model will now be described.

[0025] As shown in Figures 1 to 6, the optical waveguide of this invention includes an optical waveguide body 200, a coupling grating (not shown in the figures), and a coupling grating 100. The coupling grating and the coupling grating 100 are disposed on the optical waveguide body 200. The coupling grating is used to couple the image beam emitted by the optical engine 400 into the optical waveguide body 200, and the coupling grating 100 is used to couple the image beam out of the optical waveguide body 200 and into the human eye. The coupling grating 100 is inclined downward from the end closer to the human eye to the end farther away from the human eye. As shown in Figures 3 and 4, the optical engine 400 can be disposed on the optical waveguide body 200, and the coupling grating is used to couple the image beam emitted by the optical engine 400 into the optical waveguide body 200.

[0026] For example, the coupling grating 100 is disposed on the side of the optical waveguide body 200 near the human eye, and the coupling grating 100 is tilted upward from the optical waveguide body 200.

[0027] For example, the coupling grating 100 is disposed on the side of the optical waveguide body 200 away from the human eye, and the coupling grating 100 is inclined downward from the optical waveguide body 200.

[0028] In the conventional waveguide structure of the prior art shown in Figure 1, the light emitted by the lower electronic device 300 is reflected or diffracted to the human eye through the coupling grating 100. Since the coupling grating 100 has different diffraction angles for different wavelengths of light, a significant dispersion phenomenon is ultimately formed visually; at the same time, multiple reflections can also cause image ghosting.

[0029] The technical solution of this utility model is shown in Figures 2 to 4. The coupling grating 100 can be set on the optical waveguide body 200 on the same side as the human eye, or it can be set on the optical waveguide body 200 on a different side from the human eye. However, the coupling grating 100 must be inclined downward from the end closer to the human eye to the end farther away from the human eye. In this way, part of the interference light generated by the electronic device 300 (such as a mobile phone) below the human eye will directly enter the human eye, and part will be reflected outward and will not enter the human eye. Moreover, since the coupling grating 100 is inclined downward from the end closer to the human eye to the end farther away from the human eye, the interference light is parallel or nearly parallel to the tilt direction of the coupling grating 100. The interference light is difficult to enter the optical waveguide body 200 through effective coupling like the optical waveguide structure in the prior art in Figure 1. Even if it enters the optical waveguide body 200, it cannot be emitted normally to the human eye due to the reflection angle problem. This reduces the light reflected or diffracted to the human eye through the coupling grating 100, thereby reducing dispersion and ghosting phenomena.

[0030] Preferably, the angle between the coupling grating 100 and the optical waveguide body 200 is 15 to 60 degrees. When the angle between the coupling grating 100 and the optical waveguide body 200 is 15 to 60 degrees, it can be parallel or nearly parallel to the interfering light emitted by the electronic device 300 below the human eye under normal circumstances. At this angle, the light emitted by the electronic device 300 below the human eye, such as a mobile phone, is unlikely to meet the conditions for effective coupling into the optical waveguide body 200, thus achieving optical shielding of part of the interfering light in the physical path.

[0031] As shown in Figures 5 and 6, the duty cycle of the coupling grating is gradually varied. The grating duty cycle refers to the proportion of the width of the grating structure to one grating period, reflecting the distribution of photosensitive material in the grating structure, which will not be elaborated here. The gap between the coupling gratings 100 is not constant. By setting a gradually varying gap size, i.e., a gradual duty cycle, it is possible to reduce chromatic aberration or increase brightness.

[0032] As shown in Figure 5, the duty cycle of the coupling grating 100 gradually increases from top to bottom. The gap between the coupling gratings 100 is not constant; from top to bottom, the gap between the coupling gratings 100 gradually decreases, that is, the duty cycle gradually increases from top to bottom. This is because the lower the grating, the closer it is to the edge of the coupling grating 100. Even if light is coupled into the optical waveguide body 200, it is difficult for it to re-enter the coupling grating 100 and form diffraction. Therefore, the gradual increase in the duty cycle of the coupling grating 100 from top to bottom can effectively reduce dispersion and ghosting phenomena.

[0033] As shown in Figure 6, the duty cycle of the coupling grating 100 gradually decreases from top to bottom. From top to bottom, the gaps between the coupling gratings 100 gradually increase, which allows more light to enter the human eye. Moreover, since the coupling grating 100 is tilted downwards from the end closer to the human eye to the end farther away from the human eye, the incoming light is less likely to form dispersion and ghosting effects, thus allowing more light to enter the human eye and effectively improving image brightness.

[0034] In some embodiments, the angle between the coupling grating 100 and the optical waveguide body 200 is 25 to 45 degrees. Typical electronic devices 300, such as mobile phones, are usually placed at an angle less than 45 degrees in front of the viewer's eyes. Therefore, setting the angle between the coupling grating 100 and the optical waveguide body 200 to 25 to 45 degrees can adapt to most usage scenarios and effectively reduce chromatic aberration and ghosting phenomena.

[0035] Preferably, the angle between the coupling grating 100 and the optical waveguide body 200 is 25 degrees. When using AR glasses, with both hands hanging down and holding the phone naturally, the phone is approximately 25 degrees in front of and below the user's eyes. At this time, an angle of 25 degrees between the coupling grating 100 and the optical waveguide body 200 provides the best effect.

[0036] Preferably, the angle between the coupling grating 100 and the optical waveguide body 200 is 45 degrees. When holding the mobile phone with both hands on a table, the phone is approximately at a 45-degree angle directly in front of and below the viewer's eyes. At this angle, a 45-degree angle between the coupling grating 100 and the optical waveguide body 200 provides the best effect. As shown in Figures 3 and 4, an optical engine 400 is disposed on the optical waveguide body 200. The light beam emitted by the optical engine 400 is coupled into the optical waveguide body 200 and coupled out through the optical waveguide body 200 to the human eye. The area on the optical waveguide body 200 where the optical engine 400 is disposed is the entrance pupil area, which is mainly used to receive image light emitted from micro-displays (such as LCOS, OLED or Micro-LED) and couple it into the optical waveguide body 200. In Figures 3 and 4, the purple light emitted by the optical engine 400 represents the light emitted by the optical engine 400, which is imaged by the human eye after propagation through the optical waveguide body 200. The black light represents the light emitted by external electronic devices 300, such as mobile phones. Some light can directly pass through the gaps between the inclined coupling gratings 100 and be imaged by the human eye. Some light will be deflected out of the human eye's field of vision by reflection from the surface of the coupling gratings 100, thereby reducing or even eliminating the chromatic aberration or ghosting phenomena existing in the prior art.

[0037] The proposed solution is applied to augmented reality (AR) display systems based on diffractive waveguide structures. It mainly targets interfering light generated by electronic display devices (such as mobile phones and tablets) below. By optimizing the setting of the coupling grating structure in the waveguide, the interfering light is effectively suppressed, thereby improving the imaging quality.

[0038] The optical waveguide of this invention includes at least an entrance pupil region and an exit pupil region. Sometimes, a transition region is also provided between the entrance pupil region and the exit pupil region. The entrance pupil region is mainly used to receive image light emitted from a micro-display, such as an optical engine 400, and couple it into the optical waveguide body 200. The exit pupil region is responsible for releasing the image light from the optical waveguide body 200 to the user's eye, forming the final visible image. This invention provides a coupling grating 100 in the exit pupil region, tilted from the end facing away from the user's eye, so that the tilt direction of the coupling grating 100 is parallel or nearly parallel to the direction of the light from the electronic display device below. At the same time, the tilt angle of the coupling grating 100 is set in the range of 15 to 60 degrees, preferably 25 to 45 degrees. This design can deflect or transmit interfering light at the structural level, preventing effective coupling into the waveguide. Even if it enters the waveguide, it is difficult to exit into the user's eye through the exit pupil direction, thereby effectively blocking the propagation path of dispersion and ghosting in the entire display link. The coupling grating 100 can be set on the optical waveguide body 200 on the same side as the human eye, or it can be set on the optical waveguide body 200 on a different side from the human eye. However, the coupling grating 100 must be set tilted downwards from the end closer to the human eye to the end farther away from the human eye. This makes the setting position of the coupling grating 100 more flexible and adaptable to the needs of AR glasses with different structures.

[0039] The tilted setting of the coupling grating 100 involved in this utility model does not depend on specific materials or complex optical components. The expected suppression effect can be achieved simply by adjusting the angle and direction of the coupling grating 100 at the structural level. Therefore, it can be widely applied to various diffraction-type AR waveguide systems, including surface relief grating waveguides, volume holographic grating waveguides, etc., and has strong overall adaptability.

[0040] The advantages of implementing the optical waveguide provided by this utility model compared with the prior art are as follows: The coupling grating 100 of this invention is disposed on the optical waveguide body 200, and the coupling grating 100 is inclined downward from the end closer to the human eye to the end farther away from the human eye, so that the tilt direction of the coupling grating 100 is parallel or nearly parallel to the light from the electronic device 300 located below the human eye. This effectively reduces the interference light generated by the electronic device 300 located below the human eye from being reflected or diffracted into the human eye, which ultimately leads to obvious dispersion or ghosting phenomena in vision. The downward inclination of the coupling grating 100 from the end closer to the human eye to the end farther away from the human eye makes it difficult for some interference light to be effectively coupled into the optical waveguide body 200, and even if it enters the optical waveguide body 200, it cannot be normally emitted to the human eye. Thus, optical shielding of some interference light is achieved in the physical path. Without changing the overall structure of the optical waveguide body 200, this invention avoids the path of interference light entering the vision from the structural level, and essentially achieves root control of dispersion and ghosting problems.

[0041] This invention not only effectively controls the path of external interference light into the eye without affecting the normal display of AR images, but also retains the advantages of waveguide systems such as lightweight and wearability, providing a better optical solution for the use of diffractive waveguide AR devices in complex lighting environments.

[0042] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present utility model, and these improvements and substitutions should also be considered within the protection scope of the present utility model.

Claims

1. An optical waveguide, characterized in that, It includes an optical waveguide body, a coupling grating, and a coupling grating. The coupling grating and the coupling grating are disposed on the optical waveguide body. The coupling grating is used to couple the image beam emitted by the optomechanical system into the optical waveguide body, and the coupling grating is used to couple the image beam out of the optical waveguide body and into the human eye. The coupling grating is tilted downwards from the end closer to the human eye to the end farther away from the human eye.

2. The optical waveguide according to claim 1, characterized in that, The coupling grating is disposed on the side of the optical waveguide body near the human eye, and the coupling grating is tilted upward from the optical waveguide body.

3. The optical waveguide according to claim 1, characterized in that, The coupling grating is disposed on the side of the optical waveguide body away from the human eye, and the coupling grating is inclined downward from the optical waveguide body.

4. The optical waveguide according to claim 1, characterized in that, The angle between the grating and the surface of the optical waveguide body is 15 to 60 degrees.

5. The optical waveguide according to claim 4, characterized in that, The duty cycle of the coupled grating gradually changes.

6. The optical waveguide according to claim 5, characterized in that, The duty cycle of the coupled grating gradually increases from top to bottom.

7. The optical waveguide according to claim 5, characterized in that, The duty cycle of the coupled grating gradually decreases from top to bottom.

8. The optical waveguide according to claim 4, characterized in that, The angle between the coupling grating and the optical waveguide body is 25 to 45 degrees.

9. The optical waveguide according to claim 8, characterized in that, The angle between the coupling grating and the optical waveguide body is 25 degrees.

10. The optical waveguide according to any one of claims 1 to 9, characterized in that, An optical engine is provided on the optical waveguide body, and the light beam emitted by the optical engine is coupled into the optical waveguide body and then coupled out to the human eye through the optical waveguide body.

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