Wearable device

Abstract

The invention relates to the technical field of optical waveguides, and provides a wearable device, which comprises an optical machine and an optical waveguide member, the optical machine is used for emitting image light, the image light is imaged at a limited distance, the optical waveguide member comprises a coupling-in area and a coupling-out area, the coupling-in area is used for coupling the image light into the optical waveguide member, and the coupling-out area is used for coupling out the image light after pupil expansion. The image light emitted by the light machine is imaged at a limited distance, namely, the light beams in the image light are emitted in a non-parallel state, and after the image light is coupled into the optical waveguide from the coupling-in area, the image light is emitted in the coupling-out area after multiple times of ejection and pupil expansion, so that the adjustment of the virtual image distance can be realized more simply, and the imaging definition is improved.

Description

Technical Field

[0001] This application relates to the field of optical waveguide technology, specifically to a wearable device. Background Technology

[0002] In recent years, with the increasing maturity of virtual reality (AR) technology, micro-projection has gradually entered the commercialization stage. AR hardware display systems typically consist of two parts: a micro-optical engine and an optical combiner. The micro-optical engine used in AR devices is responsible for generating image light. The optical combiner transmits the image light emitted by the micro-optical engine and expands the pupil to deliver it to the human eye without affecting the real-world view. Common optical combiners include prism-type optical combiners, Birdbath optical combiners, off-axis holographic optical combiners, and waveguide-type optical combiners, among others.

[0003] When an optical waveguide is used as an optical combiner, it requires total internal reflection transmission and pupil expansion of the coupled beam. This necessitates that the image light propagating within it at different field-of-view angles be parallel, meaning the imaging plane of the micro-optical engine is at infinity. When the imaging plane of the micro-optical engine is not at infinity, meaning the light rays within a single field-of-view angle are not parallel, the angle between the light rays and the normal at two field-of-view angles may contain rays with the same angle. These rays, emitted by different pixels, reach the coupling region of the waveguide, where the grating performs multiple coupling and pupil expansions. At this point, the light rays with the same angle on the same surface at the outlet of the coupling region are not necessarily emitted by the same pixel; that is, light rays with the same angle from different pixels intertwine, making them indistinguishable to the human eye. When two pixels display different content, this affects the image sharpness. Summary of the Invention

[0004] This application provides a wearable device to at least partially improve the above-mentioned technical problems.

[0005] The embodiments of this application are implemented through the following technical solutions.

[0006] This application provides a wearable device, including an optical engine and an optical waveguide. The optical engine is used to emit image light, which is imaged over a finite distance. The optical waveguide includes an input region and an output region. The input region is used to couple the image light into the optical waveguide, and the output region is used to couple the image light out after pupil dilation.

[0007] In some embodiments, the optical engine includes a display panel and an imaging lens, and the image distance of the optical engine is configured to be located at h. min Between and infinity, where h min Determine h as follows: min=adT / 2. Where d is the exit pupil diameter of the imaging lens, a is the resolution of the display panel, and T is the transmittance of the optical engine.

[0008] In some embodiments, the optical engine is also provided with a driving device for driving the display panel and the imaging lens to move closer or further apart to change the image distance of the optical engine.

[0009] In some implementations, the wearable device also includes an eye-tracking system for tracking the gaze position of the user's eyes, and a drive mechanism configured to drive the imaging lens closer to or further away from the display panel based on the gaze position.

[0010] In some embodiments, the driving device includes a magnetic element and a coil coupled to each other, one of which is fixedly connected to the imaging lens and the other is fixedly disposed within the optical engine.

[0011] In some embodiments, the drive device includes a telescopic mechanism connected between the display panel and the imaging lens.

[0012] In some embodiments, the optical engine includes a first light modulator, a second light modulator, and an imaging lens. The first light modulator is used to form a first image light, and the second light modulator is used to form a second image light. The first image light and the second image light are combined and then passed through the imaging lens to form an image light.

[0013] In some implementations, the propagation distance of the first image light from the first light modulator to the imaging lens is not equal to the propagation distance of the second image light from the second light modulator to the imaging lens.

[0014] In some embodiments, the optomechanic further includes a light source and a polarizing beam splitter. The light source emits illumination light, which is incident on the polarizing beam splitter to form a first illumination light and a second illumination light. The first illumination light and the second illumination light have different polarization states. A first light modulator is used to modulate the first illumination light to form a first image light, and a second light modulator is used to modulate the second illumination light to form a second image light.

[0015] The wearable device provided in this application embodiment images the image light emitted from the optical engine at a finite distance, that is, the beam of the image light is emitted in a non-parallel state. When the image light is coupled into the optical waveguide from the coupling region, it is ejected after multiple bounces in the coupling region and then emitted with pupil expansion. This makes it easier to adjust the virtual image distance and improve the imaging clarity. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of a wearable device provided in an embodiment of this application.

[0018] Figure 2 This is a schematic diagram of the optical path for imaging in a wearable device provided in an embodiment of this application.

[0019] Figure 3 This is a schematic diagram of the structure of a driving device in a wearable device provided in an embodiment of this application.

[0020] Figure 4 This is a schematic diagram of another driving device in a wearable device provided in an embodiment of this application.

[0021] Figure 5 This is a schematic diagram of another driving device in a wearable device provided in an embodiment of this application.

[0022] Figure 6 This is a schematic diagram of the structure of an optical engine in a wearable device provided in an embodiment of this application. Detailed Implementation

[0023] To enable those skilled in the art to better understand the present invention, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0024] This embodiment provides a wearable device 10, including an optical engine 20 and an optical waveguide 60, wherein the optical engine 20 is used to emit image light, the optical waveguide 60 is used to receive image light, and after pupil dilation, the image light is coupled out, and the coupled image light can enter the human eye.

[0025] The optical waveguide 60 can be a planar structure light-transmitting device. The optical waveguide 60 includes a coupling-in region 63 and a coupling-out region 64. The coupling-in region 63 receives image light, and the coupling-out region 64 couples the image light out. The optical waveguide 60 has a first surface 61 and a second surface 62 facing away from each other. Both the first surface 61 and the second surface 62 can be planar and approximately parallel to each other. The optical waveguide 60 can provide a path for light propagation. Specifically, when image light enters the optical waveguide 60, it propagates within the optical waveguide 60 via total internal reflection. More specifically, when image light enters the optical waveguide 60, the image light rays can undergo total internal reflection within the optical waveguide 60, and then travel within the optical waveguide 60.

[0026] In another embodiment, the first surface 61 and the second surface 62 can be configured as curved surfaces, with their curvatures being approximately the same everywhere, such that the distance between the first surface 61 and the second surface 62 is approximately equal at all points. The waveguide 60 of this embodiment can be easily attached to the lenses of ordinary eyeglasses.

[0027] The coupling-in region 63 and the coupling-out region 64 can be located on the same surface of the optical waveguide 60. For example, the coupling-in region 63 and the coupling-out region 64 can be located on either the first surface 61 or the second surface 62. Alternatively, the coupling-in region 63 and the coupling-out region 64 can be located on different surfaces of the optical waveguide 60. For example, the coupling-in region 63 can be located on the first surface 61, and the coupling-out region 64 can be located on the second surface 62. This embodiment does not limit this. In this embodiment, both the coupling-in region 63 and the coupling-out region 64 are located on the second surface 62 of the optical waveguide 60.

[0028] In some embodiments, the coupling region 63 is provided with a coupling grating 65. When image light is incident on the coupling grating 65, the coupling grating 65 diffracts the image light, thereby coupling the image light into the optical waveguide 60. The coupling region 64 may be provided with a coupling grating 66. When image light propagates within the optical waveguide 60 to the coupling region 64, the image light is dilated multiple times on the coupling grating 66 before being coupled out.

[0029] The optical engine 20 can be configured corresponding to the coupling region 63 of the optical waveguide 60, so that the image light emitted from the optical engine 20 can be directly incident on the coupling region 63, thereby reducing the number of relay elements in the image light propagation process and reducing the overall size of the wearable device 10. In this embodiment, the image light emitted from the optical engine 20 is imaged over a finite distance; that is, the beams of the image light emitted from the optical engine 20 are non-parallel, and the non-parallel image light beams will intersect and image within a finite distance. This configuration allows for relatively simple adjustment of the virtual image distance, thereby improving image clarity.

[0030] In a more specific manner, the optical engine 20 may include a display panel 30 and an imaging lens 40. The display panel 30 generates image light, which is emitted through the imaging lens 40. The display panel 30 may be, for example, a μLED panel. In this embodiment, the image distance of the optical engine 20 can be configured to be located at h. min Between and infinity.

[0031] Specifically, see Figure 2 , Figure 2 A schematic diagram of the optical path is shown for an imaging lens 40 with an aperture size of d, imaging at a position at a distance h. The edge rays corresponding to each image point form an angle, such as A1 and A2. The angle between the left edge ray and the normal of A1 is greater than the angle between the right edge ray and the normal of A1. That is, to ensure the optical waveguide does not affect image sharpness, the angle β between the right edge ray and the normal of A2 needs to be greater than the angle α between the left edge ray and the normal of A1. In other words, the ray angles corresponding to A1 are all smaller than the ray angles corresponding to A2. Based on geometric relationships:

[0032] but:

[0033]

[0034] Assuming the resolution of display panel 30 is 'a', if the corresponding Nyquist frequency modulation is 100%, then its Nyquist frequency is 2 / a. That is, the maximum frequency information that display panel 30 can display is 2 / a, at which point the user can distinguish two white pixels sandwiched between one black pixel. There is a formula... The result obtained after converting the two formulas is: If L1 is expressed as a transmittance T relationship, then That is to say Therefore, h min Determine h as follows: min =adT / 2. Where d is the exit pupil diameter of the imaging lens 40, a is the resolution of the display panel 30, and T is the transmittance of the optical engine 20. Taking a common miniature optical engine 20 as an example, the horizontal resolution a is 854, the viewing angle resolution (PPD) is 30 pixels / °, and the exit pupil size d of the imaging lens 40 is 3mm. At this time, h min That is, 2.5m.

[0035] When the image distance of the optical engine 20 is at h min When the distance is between infinity and the distance between infinity, although the image light output by the optical engine 20 is non-parallel light, the optical waveguide 60 will not affect the image clarity during the propagation of the optical waveguide 60 and the pupil expansion process, and the clarity of the image seen by the user will not decrease.

[0036] In some embodiments, the optical engine 20 may further include a driving device 80, which drives the display panel 30 and the imaging lens 40 to move closer or further apart, thereby changing the image distance of the optical engine 20. This allows the image distance of the optical engine 20 to be adjusted according to the desired viewing angle, ensuring that the image distance always meets the user's viewing needs and preventing a decrease in the clarity of the image seen by the user. For example, different users have different eye focal points and habitual viewing positions; therefore, users can control and change the distance between the display panel 30 and the imaging lens 40 according to their viewing needs, thereby changing the image distance of the optical engine 20 and resulting in a clearer image.

[0037] For a more specific implementation method, see [link to relevant documentation]. Figure 3 The driving device 80 may include a magnetic element 81 and a coil 82 coupled to each other. One of the magnetic element 81 or the coil 82 is fixedly connected to the imaging lens 40, and the other is fixedly disposed within the optical engine 20. Specifically, the optical engine 20 may include a housing, with one of the magnetic element 81 or the coil 82 fixedly disposed inside the housing and the other fixedly connected to the imaging lens 40. For example, the magnetic element 81 is fixedly disposed inside the housing of the optical engine 20, and the coil 82 is fixed to the imaging lens 40. When the coil 82 is energized, under the magnetic force of the magnetic element 81, the coil 82 moves, thereby causing the imaging lens 40 to move closer to or away from the display panel 30. In some other embodiments, the magnetic element 81 may be fixed inside the optical engine 20, and the coil 82 may be fixedly connected to the display panel 30. When the coil 82 is energized, under the magnetic force of the magnetic element 81, the coil 82 moves, thereby causing the display panel 30 to move closer to or away from the imaging lens 40.

[0038] As another, more specific implementation method, see Figure 4 The driving device 80 may include a shape memory metal part 83, which is connected to the housing of the imaging lens 40 and the optical engine 20. The shape memory metal part 83 can be driven to move and reset by other driving components, such as micro motors, to achieve relative proximity or distance between the display panel 30 and the imaging lens 40.

[0039] As another, more specific implementation method, see Figure 5 The driving device 80 may include a telescopic mechanism 85, which is disposed between the display panel 30 and the imaging lens 40. The telescopic mechanism 85 moves the display panel 30 closer to or further away from the imaging lens 40 through its telescopic movement. It is understood that the telescopic mechanism 85 can be any structure capable of telescopic movement, such as threaded telescopic or sliding telescopic mechanisms; this embodiment does not limit this.

[0040] In other embodiments, the drive device 80 may also take other forms, which will not be described exhaustively in this embodiment.

[0041] During the user's viewing of the image, their eyes may move as their gaze changes. This causes changes in the eye's focus and gaze point. Therefore, to ensure the clarity of the image remains consistent, the image distance of the optical engine 20 needs to change with eye movement. This way, even if the user's eyes move and the gaze point changes, the resolution of the viewed image remains unchanged. Therefore, in some embodiments, the wearable device 10 may also include an eye-tracking system to track the user's eye gaze position. The eye-tracking system can be positioned on the side of the waveguide 60 closest to the user's eye, and the driving device 80 is configured to drive the imaging lens 40 closer to or further away from the display panel 30 based on the gaze position. This configuration ensures that the resolution of the viewed image remains consistent even if the user's eyes move and the gaze point changes.

[0042] The wearable device 10 provided in this embodiment has an image light emitted from the optical engine 20 that is imaged at a limited distance, that is, the beam of the image light is emitted in a non-parallel state. After the image light is coupled into the optical waveguide 60 from the coupling region 63, it is ejected after multiple bounces in the coupling region 64 and then emitted with a pupil expansion. This makes it easier to adjust the virtual image distance and improve the image clarity.

[0043] In another implementation, see Figure 6 The optical engine 20 includes a first optical modulator 21 and a second optical modulator 22. The first optical modulator 21 forms a first image light, and the second optical modulator 22 forms a second image light. The first and second image lights are combined to form an image light. The first and second image lights can display the same image content. Simultaneously, the first and second optical modulators 21 and 22 can operate at the same time. Thus, when the first and second image lights are guided through the optical waveguide 60 and coupled out through the pupil, they enter the human eye, allowing the user to view two overlapping images, creating a three-dimensional effect. In other embodiments, the first and second optical modulators 21 and 22 can operate in a time-division multiplexing manner; that is, when the first optical modulator 21 is operating, the second optical modulator 22 is off, and vice versa.

[0044] The first optical modulator 21 and the second optical modulator 22 can be either LCoS or LCD, and this embodiment does not limit them.

[0045] In this embodiment, the image light formed by combining the first and second image lights is imaged over a finite distance. That is, the beams of image light emitted from the optomechanical system 20 are non-parallel, and the non-parallel image lights will intersect and form an image over a finite distance. This configuration allows for relatively simple adjustment of the virtual image distance, thereby improving image clarity.

[0046] In this embodiment, the propagation distance of the first image light from the first light modulator 21 to the imaging lens 40 is configured to be unequal to the propagation distance of the second image light from the second light modulator 22 to the imaging lens 40. The advantage of this configuration is that the first and second image lights have different image distances. Due to the robustness of the human eye, a certain difference between the viewing distance and the image distance is acceptable. The closer the viewing distance and the image distance are, the more comfortable it is for the human eye. Since the human eye generally does not gaze at infinity, and when using the wearable device 10, it does not gaze at particularly close positions, such as a few centimeters in front of its eyes, there are two virtual image distances between infinity and the minimum clear image distance. One virtual image distance is relatively large, satisfying viewing at a greater distance. The other virtual image distance is relatively small, satisfying viewing at a smaller distance, which can also reduce or eliminate convergence conflict problems.

[0047] Furthermore, the optomechanical system 20 also includes a light source 70, which emits illumination light. The illumination light is incident on the first light modulator 21 and the second light modulator 22 and is modulated to form the first image light and the second image light. To improve the utilization rate of the light source 70, the optomechanical system 20 may further include a polarizing beam splitter 50. Illumination light emitted from the light source 70 is incident on the polarizing beam splitter 50 to form a first illumination light and a second illumination light. The polarization states of the first and second illumination lights are different. A first light modulator 21 is used to modulate the first illumination light to form a first image light. The first image light is reflected again to the polarizing beam splitter 50 and emitted to the imaging lens 40. The propagation distance of the first image light from the first light modulator 21 to the imaging lens 40 is L1. A second light modulator 22 is used to modulate the second illumination light to form a second image light. The second image light is reflected back to the polarizing beam splitter 50 and then reflected again to the imaging lens 40. The propagation distance of the second image light from the second light modulator 22 to the imaging lens 40 is L2. L1 and L2 are not equal. This implementation can fully utilize both P-rays and S-rays in the light emitted from the light source 70, improving light efficiency.

[0048] In this case, the first image light can be S-polarized light, and the second image light can be P-polarized light; or the first image light can be P-polarized light, and the second image light can be S-polarized light.

[0049] In other embodiments, the positions of the first light modulator 21 and the second light modulator 22 can be adjusted so that the propagation distance of the first image light from the first light modulator 21 to the imaging lens 40 is not equal to the propagation distance of the second image light from the second light modulator 22 to the imaging lens 40. This embodiment does not limit this.

[0050] The wearable device 10 provided in this embodiment includes, but is not limited to, augmented reality (AR), virtual reality (VR), and mixed reality (MR) devices. For example, in a more specific embodiment, the wearable device 10 may be AR glasses.

[0051] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A wearable device, characterized in that, include: An optical engine for emitting image light, which images the light over a finite distance; as well as An optical waveguide includes an input region and an output region. The input region is used to couple the image light into the optical waveguide, and the output region is used to couple the image light out after pupil dilation.

2. The wearable device according to claim 1, characterized in that, The optical engine includes a display panel and an imaging lens, and the image distance of the optical engine is configured to be located at h. min Between and infinity, where h min Determine h as follows: min =adT / 2. Where, d is the exit pupil diameter of the imaging lens, a is the resolution of the display panel, and T is the transmittance of the optical engine.

3. The wearable device according to claim 2, characterized in that, The optical engine is also provided with a driving device, which is used to drive the display panel and the imaging lens to move closer or further apart to change the image distance of the optical engine.

4. The wearable device according to claim 3, characterized in that, The wearable device also includes an eye-tracking system for tracking the gaze position of the user's eyes, and the driving device is configured to drive the imaging lens closer to or further away from the display panel based on the gaze position.

5. The wearable device according to claim 3 or 4, characterized in that, The driving device includes a magnetic component and a coil coupled to each other, one of which is fixedly connected to the imaging lens, and the other is fixedly disposed inside the optical engine.

6. The wearable device according to claim 3 or 4, characterized in that, The driving device includes a shape memory metal component and a driving component. The shape memory metal component is connected to the imaging lens, and the driving component is used to drive the shape memory metal component to move.

7. The wearable device according to claim 3 or 4, characterized in that, The driving device includes a telescopic mechanism, which is connected between the display panel and the imaging lens.

8. The wearable device according to claim 1, characterized in that, The optical engine includes a first light modulator, a second light modulator, and an imaging lens. The first light modulator is used to form a first image light, and the second light modulator is used to form a second image light. The first image light and the second image light are combined and then passed through the imaging lens to form the image light.

9. The wearable device according to claim 8, characterized in that, The propagation distance of the first image light from the first light modulator to the imaging lens is not equal to the propagation distance of the second image light from the second light modulator to the imaging lens.

10. The wearable device according to claim 9, characterized in that, The optical engine further includes a light source and a polarizing beam splitter. The light source is used to emit illumination light. After the illumination light is incident on the polarizing beam splitter, it forms a first illumination light and a second illumination light. The polarization states of the first illumination light and the second illumination light are different. The first light modulator is used to modulate the first illumination light to form the first image light, and the second light modulator is used to modulate the second illumination light to form the second image light.

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