Augmented reality display component and augmented reality display device having the same

Abstract

The present invention provides an augmented reality display component, including an image unit and an eyepiece unit, characterized in that a refraction unit is arranged between the image unit and the eyepiece unit, the refraction unit includes a polarizer, an optical switch and a birefringent crystal, the polarizer is arranged between the optical switch and the image unit, the birefringent crystal is arranged between the optical switch and the eyepiece unit, the birefringent crystal refracts the linearly polarized light transmitted from the optical switch and enables the eyepiece unit to have a first depth of field and a second depth of field. The present invention also provides a display device using the above-mentioned augmented reality display component. The augmented reality display component provided by the present invention arranges a polarizer, an optical switch and a birefringent crystal between the image unit and the eyepiece unit, and uses the different refraction effects of the birefringent crystal on polarized light in different polarization directions to form images with different depths of field, thereby solving the problem of adjusting convergence conflict and having broad application prospects.

Description

Technical Field

[0001] The present invention relates to the field of augmented reality technology, and in particular to an augmented reality display component and an augmented reality display device having the component. Background Art

[0002] Augmented reality (AR) technology can integrate the virtual world and the real world on the screen. It achieves a sensory experience that transcends and increases reality through the real-time superposition of multi-sensory simulated information such as vision and hearing with real environmental information. It has extremely broad application prospects in many fields such as entertainment, medical care, and military. The augmented reality display component is the core component of the entire system, which directly displays the superimposed image of simulated information and environmental information to the user. Existing augmented reality display components generally use a fixed depth of field display method, such as displaying virtual images to infinity (maximum depth of field). However, the existing fixed depth of field display method does not conform to the convergence reflex observation law of the human eye, which makes users prone to nausea, dizziness and other symptoms after watching for a long time. Summary of the invention

[0003] In view of this, it is necessary to provide an improved augmented reality display component and an augmented reality display device having the component. The multiple depths of field of the augmented reality display component can prevent users from experiencing symptoms such as nausea and dizziness after long-term viewing.

[0004] The present invention provides an augmented reality display component, comprising an image unit and an eyepiece unit, characterized in that a refraction unit is arranged between the image unit and the eyepiece unit, the refraction unit comprises a polarizer, an optical switch and a birefringent crystal, the polarizer is arranged between the optical switch and the image unit, the birefringent crystal is arranged between the optical switch and the eyepiece unit, the birefringent crystal refracts linearly polarized light transmitted from the optical switch and enables the eyepiece unit to have a first depth of field and a second depth of field.

[0005] Furthermore, the difference in refractive index of the birefringent crystal to linearly polarized light in different polarization directions is greater than 0.2.

[0006] Furthermore, the eyepiece unit includes an aspherical lens, and the surface equation of the aspherical lens is:

[0007]

[0008] Where c is the curvature at the vertex of the surface; k is the quadratic constant of the surface, A i is the i-th order aspheric coefficient of the surface.

[0009] Furthermore, the refraction unit further includes a projection unit, and the projection unit is located between the birefringent crystal and the eyepiece unit.

[0010] Furthermore, the augmented reality display component also includes a control unit, which is communicatively connected to the image unit and the optical switch.

[0011] Furthermore, the resolution of the image unit is above 1080P.

[0012] Furthermore, the brightness of the image unit is greater than 5000 nits; and / or,

[0013] The refresh rate of the image unit is above 120 Hz.

[0014] Furthermore, the response time of the optical switch is less than 10 milliseconds; and / or,

[0015] The light transmittance of the optical switch is greater than 90%.

[0016] Furthermore, the extinction ratio of the polarizer is greater than 10000:1.

[0017] The present invention also provides an augmented reality display device, comprising an augmented reality display component, wherein the augmented reality display component is any one of the augmented reality display components described above.

[0018] The augmented reality display component provided by the present invention is provided with a polarizer, an optical switch and a birefringent crystal between an image unit and an eyepiece unit, and uses the different refraction effects of the birefringent crystal on polarized light in different polarization directions to form images with different depths of field, so that virtual information of any depth can be presented, and the adjustment convergence conflict is solved, which not only improves the user experience, but also can be more in line with the observation habits of the human eye, and can avoid the user from experiencing adverse reactions such as fatigue, nausea, vomiting, etc. after long-term observation, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of the structure of an augmented reality display component in one embodiment of the present invention;

[0020] Figure 2 Schematic diagram of the optical path after adding a compensation surface to the eyepiece unit;

[0021] Figure 3 To show the MTF curve of the image at the first depth of field,

[0022] Figure 4 To display the distortion grid of the image at the first depth of field,

[0023] Figure 5 To show the MTF curve of the image at the second depth of field,

[0024] Figure 6A distortion grid showing the image at the second depth of field.

[0025] Main component symbols

[0026] Augmented reality display components 100 Image Unit 10 Eyepiece unit 20 Aspherical lens 21 Refraction Unit 30 Polarizer 31 Optical Switch 32 Birefringent Crystals 33 Projection unit 34

[0027] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] It should be noted that when a component is referred to as being "mounted on" another component, it may be directly mounted on the other component or there may be a central component. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be a central component at the same time. When a component is considered to be "fixed to" another component, it may be directly fixed on the other component or there may be a central component at the same time.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "or / and" used herein includes any and all combinations of one or more of the related listed items.

[0031] See also Figure 1 , Figure 1 FIG. 1 is a schematic diagram of the structure of an augmented reality display component 100 in one embodiment of the present invention. The augmented reality display component 100 is provided for observation by a user and is used to display image information projected into the user's eyes.

[0032] In this embodiment, the augmented reality display component 100 is applied to wearable augmented reality glasses (not shown), and the augmented reality display component 100 serves as the lens of the augmented reality glasses. The user observes the virtual environment information and the real environment information by wearing the augmented reality glasses and observing the augmented reality display component 100.

[0033] It can be understood that in other embodiments, the augmented reality display component 100 is also applied to other devices such as wearable helmets, as long as the augmented reality display component 100 can be perceived and observed by the user.

[0034] The augmented reality display component 100 includes an image unit 10, an eyepiece unit 20 and a refraction unit 30, wherein the refraction unit 30 is located between the image unit 10 and the eyepiece unit 20; the image unit 10 is used to display image information for observation by a user, the eyepiece unit 20 is used to converge the image light refracted by the refraction unit 30 and transmit it to the human eye for imaging, and the refraction unit 30 is used to selectively refract the image light provided by the image unit 10.

[0035] The image light provided by the image unit 10 changes its polarization direction after the selective refraction of the refraction unit 30, and then converges at different positions after being converged by the eyepiece unit 20, thereby forming different depths of field.

[0036] Specifically, the image unit 10 is a display, which may be a CRT display, an LCD display, a PDP display or an OLED display.

[0037] In this embodiment, considering the comprehensive performance and cost advantages, the image unit 10 in this embodiment uses Sony OLED screen ECX337A display, which is a micro display with a diagonal length of only 0.5 inches and a resolution of 1280×960. It has better product competitiveness and relatively better user experience.

[0038] It can be understood that in other embodiments, the image unit 10 can also use other displays besides the Sony OLED screen ECX337A display. The present invention does not limit the specific type of display used by the image unit 10, nor does it limit the specific model of the display selected by the image unit 10, as long as the display used by the image unit 10 can normally output environmental image information and virtual image information.

[0039] The eyepiece unit 20 is located between the user's eyes and the image unit 10. The eyepiece unit 20 can be tilted relative to the image unit 10 as needed, so as to smoothly guide the image information to the user's eyes.

[0040] It can be understood that the eyepiece unit 20 can use either a positive eyepiece or other types of eyepieces other than the positive eyepiece, such as a negative eyepiece; the number of eyepieces included in the eyepiece unit 20 can be one or more.

[0041] The refraction unit 30 includes a polarizer 31 , an optical switch 32 and a birefringent crystal 33 . The polarizer 31 is disposed between the image unit 10 and the optical switch 32 , and the birefringent crystal 33 is located between the optical switch 32 and the eyepiece unit 20 .

[0042] The polarizer 31 is used to convert the image light displayed by the image unit 10 from natural light into linearly polarized light, and the optical switch 32 is used to adjust the polarization direction of the linearly polarized light, so that the natural light emitted by the image unit 10 has different polarization directions; the birefringent crystal 33 is used to refract the linearly polarized light transmitted from the optical switch 32, so that the linearly polarized light with different polarization directions has different refraction directions.

[0043] The natural light containing image information emitted from the image unit 10 is converted into linearly polarized light under the polarizing effect of the polarizer 31, and then forms different polarization directions under the adjustment effect of the optical switch 32, and finally forms an image display with dual depth of field under the different refraction effects of the birefringent crystal 33 on polarized light with different polarization directions.

[0044] Specifically, the polarizer 31 can convert light into polarized light under natural light conditions, and it uses the anisotropy of optical properties of specific materials to polarize natural light.

[0045] In this embodiment, the polarizer 31 uses a polarizing plate to polarize the natural light containing image information emitted by the image unit 10. The polarizer 31 can be a microcrystalline polarizing plate such as a tourmaline wafer or a molecular polarizing plate such as a wire grid polarizing plate.

[0046] It is understandable that in other embodiments, the polarizer 31 may also be a polarizing beam splitter prism or other types of polarizers other than a polarizing plate, as long as the polarizer of this type can polarize the image information.

[0047] The optical switch 32 is connected to the polarizer 31 and is used to adjust the polarization direction of the optical signal output by the polarizer 31. When the optical switch 32 is turned on, the optical switch 32 acts on the polarizer 31; when the optical switch 32 is turned off, the optical switch 32 has no regulating effect on the optical signal output by the polarizer 31.

[0048] As for the structure of the optical switch 32 itself, it can adopt a conventional structure. In this embodiment, the optical switch 32 adopts a liquid crystal light valve; preferably, the response time of the optical switch 32 is set to be less than 10 milliseconds, and the light transmittance of the optical switch 32 is set to be greater than 90%.

[0049] It can be understood that in other embodiments, the optical switch 32 can also adopt other types of optical switch elements such as electro-optical switches, thermo-optical switches, acousto-optic switches, micromechanical optical switches and traditional mechanical optical switches, as long as the optical switch 32 of this type can achieve the direction adjustment of the polarizer 31; the response time and transmittance of the optical switch 32 can be selected according to the actual working conditions, for example, the response time of the optical switch 32 is set to more than 10 milliseconds, and the transmittance of the optical switch 32 is set to be less than 90%.

[0050] The birefringent crystal 33 is located on the optical path between the optical switch 32 and the eyepiece unit 20, and is used to refract polarized light. The birefringent crystal 33 has different refractive indices for linear polarized light with different polarization directions. The cooperation between the birefringent crystal 33 and the optical switch 32 can make the image light have different transmission directions after the action.

[0051] In this embodiment, the birefringent crystal 33 is a birefringent crystal prism; the birefringent crystal 33 uses a birefringent crystal prism, which can make the light parallel to each other between the incident surface on the birefringent crystal prism and the optical axis and the exit surface of the birefringent crystal prism. The linear polarized light with different polarization directions only has different refractive indices when passing through the birefringent crystal 33, and the main light is still in a state of overlap and misalignment, and no additional aberrations will be generated.

[0052] Furthermore, the refractive index of the birefringent crystal 33 for O light is 1.6585, and the refractive index for E light is 1.4865.

[0053] It can be understood that in other embodiments, the birefringent crystal 33 can also have other shapes besides the birefringent crystal prism, as long as the birefringent crystal 33 of this shape and type can refract the linear polarized light adjusted by the optical switch 32; the birefringent crystal 33 can also use other refractive indices besides the above-mentioned refractive indices for different polarized light (such as O light or E light), as long as the refractive indices of the birefringent crystal 33 for polarized light in different polarization directions are different.

[0054] In actual use, considering that the optical switch 32 needs to continuously switch its on / off state, the optical switch 32 preferably has a higher response frequency, so that the optical switch 32 has sufficient response speed to switch its on / off state and adapt to different display requirements of the image unit 10.

[0055] The following briefly explains the display principle of the augmented reality display component 100 with multiple depths of field:

[0056] After the image light generated by the image unit 10 passes through the polarizer 31 in the refraction unit 30, only linear polarized light (such as ordinary light, referred to as O light) of a certain characteristic direction will remain; when the optical switch 32 is turned on, the linear polarized light (O light) will be converted into linear polarized light of another polarization direction (such as extraordinary light, referred to as E light) through the regulation of the optical switch 32. When the optical switch 32 is turned off, the optical switch 32 does not change the polarization direction of the linear polarized light, and the linear polarized light (O light) is directly incident on the birefringent crystal 23;

[0057] The birefringent crystal 33 has different refractive indices for linear polarized light in different directions; when the optical switch 32 is turned on, the birefringent crystal 33 refracts the O light at a first refraction angle, and the image light in the form of O light is converged to the human eye after passing through the converging effect of the eyepiece unit 20, thereby obtaining an image that can be observed by the user and has a first depth of field; when the optical switch 32 is turned off, the birefringent crystal 33 refracts the E light at a second refraction angle, and the image light in the form of E light is converged to the human eye after passing through the converging effect of the eyepiece unit 20, thereby obtaining an image that can be observed by the user and has a second depth of field, thereby completing the dual depth of field display process of the augmented reality display component 100.

[0058] Furthermore, when the optical switch 32 is continuously refreshed at an appropriate frequency, the depth of field perceived by the human eye may be between the first depth of field and the second depth of field, thereby forming a controllable adjustment of the optical parameter of the depth of field between the first depth of field and the second depth of field.

[0059] It should be noted that the present invention does not limit the optical switch 32 to only be able to adjust the direction of the O light to the E light. It is understandable that in other embodiments, the optical switch 32 can also adjust the direction of the E light to the O light.

[0060] The augmented reality display component 100 provided by the present invention is provided with a polarizer 31, an optical switch 32 and a birefringent crystal 33 between the image unit 10 and the eyepiece unit 20, and uses the different refraction effects of the birefringent crystal 33 on polarized light in different polarization directions to form images with different depths of field, so that virtual information of any depth can be presented, and the adjustment convergence conflict is solved, which not only improves the user experience, but also can be more in line with the observation habits of the human eye, and can avoid the user from experiencing adverse reactions such as fatigue, nausea, vomiting, etc. after long-term observation, and has broad application prospects.

[0061] In one embodiment of the present invention, the refraction unit 30 also includes a projection unit 34, which is located between the birefringent crystal 33 and the eyepiece unit 20. The projection unit 34 is used to transmit the linearly polarized light transmitted by the birefringent crystal 33 into an enlarged relay real image. The projection unit 34 uses its own relay amplification effect to make the image signal output by the refraction unit 30 be transmitted to the eyepiece unit 20 more clearly, thereby reducing the transmission loss between the refraction unit 30 and the eyepiece unit 20, and realizing image transmission over a longer distance.

[0062] Furthermore, the projection ratio of the projection unit 34 is preferably less than 1.6 to reduce the structural compactness of the projection unit, effectively reduce the spatial scale of the entire assembly and reduce the optical path space, leaving more room for industrial design and making it more ergonomic.

[0063] In this embodiment, the projection unit 34 includes four lenses, and the eyepiece unit 20 includes two semi-transparent and semi-reflective lenses. The data of the equivalent optical path is shown in Table 1:

[0064] Table 1 Equivalent optical path data table

[0065]

[0066]

[0067] Please also read Figure 2 , Figure 2 The diagram is a light path diagram after a compensation surface is added to the eyepiece unit 20. The function of adding the compensation surface to the eyepiece unit 20 is to ensure that when the human eye views the real world through the eyepiece unit, the image of the real world is not distorted.

[0068] Please also read Figures 3 to 6 , Figure 3 To show the MTF curve of the image at the first depth of field, Figure 4 To display the distortion grid of the image at the first depth of field, Figure 5 To show the MTF curve of the image at the second depth of field, Figure 6 A distortion grid showing the image at the second depth of field.

[0069] In this embodiment, the pupil diameter is 10 mm, the pupil distance is 18 mm, and the full field angle is 50 degrees. Excellent imaging quality is obtained at the first depth and the second depth, the maximum field distortion is less than 0.2%, and the maximum field of view has an MTF (Modulation Transfer Function) greater than 0.4 at a cutoff frequency of 30 lp / mm. The MTF value of the maximum field of view at the second depth at a cutoff frequency of 30 lp / mm reaches more than 0.6, and an excellent light field display effect can be obtained.

[0070] In one embodiment of the present invention, the augmented reality display component 100 is further provided with a control unit (not shown), which is connected to the optical switch 32 and the image unit 10 through a medium such as a wire, and is used to synchronously control the operating states of the optical switch 32 and the image unit 10, and control the opening and closing of the optical switch 32 according to the depth of field required to be displayed by the image unit 10. Integrating the control unit inside the augmented reality display component 100 can improve the integration of the entire system and help realize the control function of the entire system.

[0071] It can be understood that in other embodiments, the control unit can also be arranged outside the augmented reality display component 100, that is, the control unit is arranged outside the augmented reality display component 100 as an environmental element, as long as the control unit can communicate with the optical switch 32 and the image unit 10 and coordinate and control the operating status of the optical switch 32 and the image unit 10.

[0072] In one embodiment of the present invention, in order to improve the quality of image display, the resolution of the image unit 10 is preferably 1080P or above, and the brightness of the image unit 10 is preferably above 5000 nits. Setting the resolution and brightness of the image unit 10 to be higher helps to improve the realism of the image information display and the user experience, so that the virtual image information superimposed on the real image information is more realistic.

[0073] In one embodiment of the present invention, in order to ensure the user experience and take into account the dual-depth image display, the refresh rate of the image unit 10 is 120 Hz or more (twice or more than the single-depth 60 Hz), so that the user does not feel flickering when observing; and / or,

[0074] The extinction ratio of the polarizer 31 is above 10000:1, so that the polarized light after polarization by the polarizer 31 will not contain both o-light and e-light, thereby ensuring that the image observed by the user through the eyepiece unit 20 will not exist at two depths at the same time, avoiding image crosstalk and improving the quality of imaging.

[0075] In one embodiment of the present invention, in order to reduce the thickness of the birefringent crystal 33, the refractive index difference of the birefringent crystal 33 for o-light or e-light is preferably greater than 0.2, thereby reducing the requirement for the thickness of the birefringent crystal 33 during refraction and further reducing the system load.

[0076] In one embodiment of the present invention, in order to improve the user's field of view, the eyepiece unit 20 of the present invention includes an aspherical lens 21, and the surface equation of the aspherical lens 21 is:

[0077]

[0078] Where c is the curvature at the vertex of the surface; k is the quadratic constant of the surface, A i is the i-th order aspheric coefficient of the surface.

[0079] The aspherical lens 21 used in the present invention has the advantages of a large exit pupil diameter, a long exit pupil distance, and a wide field of view. The large exit pupil diameter can meet the needs of users who squint when wearing the lens, and the long exit pupil distance can meet the needs of users who wear myopia glasses and hyperopia glasses. The wide field of view can present virtual information more realistically, so that virtual information and the real world are better integrated. According to experimental measurements, the field of view of the aspherical lens 21 used in the present invention can reach 50°, which has a wider field of view and better user experience.

[0080] Of course, the augmented reality display component 100 may also be equipped with a variety of functional elements to improve the user experience. For example, an inertial measurement unit (IMU) may be integrated on the augmented reality display component 100. The control unit controls the inertial measurement unit to detect the posture of the entire device, thereby further improving the user experience.

[0081] The present invention also provides an augmented reality display device (not shown), which includes a wearable device body (not shown) and an augmented reality display component 100 disposed on the device body. The augmented reality display device provided by the present invention uses the augmented reality display component 100 to enable itself to display images with dual depth of field, and has a wide range of application prospects.

[0082] The augmented reality display component 100 provided by the present invention is provided with a polarizer 31, an optical switch 32 and a birefringent crystal 33 between the image unit 10 and the eyepiece unit 20, and uses the different refraction effects of the birefringent crystal 33 on polarized light in different polarization directions to form images with different depths of field, so that virtual information of any depth can be presented, and the adjustment convergence conflict is solved, which not only improves the user experience, but also can be more in line with the observation habits of the human eye, and can avoid the user from experiencing adverse reactions such as fatigue, nausea, vomiting, etc. after long-term observation, and has broad application prospects.

[0083] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0084] Those skilled in the art should recognize that the above embodiments are only used to illustrate the present invention, and are not intended to limit the present invention. As long as they are within the spirit of the present invention, appropriate changes and modifications to the above embodiments are within the scope of protection claimed by the present invention.

Claims

1. An augmented reality display component, comprising an image unit and an eyepiece unit, characterized in that: A refraction unit is arranged between the image unit and the eyepiece unit, the refraction unit comprises a polarizer, an optical switch and a birefringent crystal, the polarizer is arranged between the optical switch and the image unit, the birefringent crystal is arranged between the optical switch and the eyepiece unit and is located on an optical path between the optical switch and the eyepiece unit, the birefringent crystal refracts linearly polarized light transmitted from the optical switch and enables the eyepiece unit to have a first depth of field and a second depth of field; The natural light including the image information emitted from the image unit is converted into linear polarized light under the polarization effect of the polarizer, the optical switch is connected to the polarizer, and is used to adjust the polarization direction of the optical signal output by the polarizer, and the birefringent crystal has different refractive indices for linear polarized light with different polarization directions; When the optical switch is turned on, the birefringent crystal refracts the 0 light at a first refraction angle, and the image light in the form of the 0 light is converged to the human eye after passing through the convergence effect of the eyepiece unit, so as to obtain an image of a first depth of field; when the optical switch is turned off, the birefringent crystal refracts the E light at a second refraction angle, and the image light in the form of the E light is converged to the human eye after passing through the convergence effect of the eyepiece unit, so as to obtain an image of a second depth of field; The refraction unit also includes a projection unit, which is located between the birefringent crystal and the eyepiece unit and is used to transmit the linearly polarized light transmitted by the birefringent crystal into an enlarged relay real image for transmission to the eyepiece unit; the projection ratio of the projection unit is less than 1.

6.

2. The augmented reality display assembly according to claim 1, wherein: The difference in refractive index of the birefringent crystal to linearly polarized light in different polarization directions is greater than 0.

2.

3. The augmented reality display assembly according to claim 1, wherein: The eyepiece unit includes an aspherical lens, and the surface equation of the aspherical lens is: Among them, c is the curvature at the vertex of the surface; k is the quadratic surface constant of the surface, and Ai is the i-th order aspheric coefficient of the surface.

4. The augmented reality display assembly according to claim 1, wherein: The augmented reality display component also includes a control unit, which is communicatively connected to the image unit and the optical switch.

5. The augmented reality display assembly according to claim 1, wherein: The resolution of the image unit is above 1080P.

6. The augmented reality display assembly according to claim 5, characterized in that: The brightness of the image unit is greater than 5000 nits; and / or, The refresh rate of the image unit is above 120 Hz.

7. The augmented reality display assembly according to claim 1, wherein: The response time of the optical switch is less than 10 milliseconds; and / or, The light transmittance of the optical switch is greater than 90%.

8. The augmented reality display assembly according to claim 1, wherein: The extinction ratio of the polarizer is greater than 10000:

1.

9. An augmented reality display device, comprising an augmented reality display component, characterized in that: The augmented reality display component is the augmented reality display component described in any one of claims 1 to 8.

Images