CN112014971A - Augmented reality display assembly and augmented reality display device with same - Google Patents

Abstract

The invention provides an augmented reality display component, which comprises an image unit, an ocular unit and a refraction unit, wherein the refraction unit comprises a first optical switch and a first birefringent crystal, the first optical switch is positioned between the image unit and the first birefringent crystal, the refraction unit also comprises a second birefringent crystal and a first phase retarder, the phase delay of the first phase retarder is pi/2 and the first phase retarder is arranged between the first birefringent crystal and the second birefringent crystal. The invention also provides display equipment applying the augmented reality display component. The invention realizes a multi-depth-of-field spherical imaging image output mode by utilizing the first birefringent crystal, the second birefringent crystal and the first phase delayer arranged between the first birefringent crystal and the second birefringent crystal, can ensure that the quality of image output is maintained in a high-quality output mode of a spherical surface, has less image distortion and improved imaging definition, and has wide application prospect and extremely high economic value.

Description

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

technical field

The present invention relates to the technical field of augmented reality, and in particular, to an augmented reality display assembly and an augmented reality display device having the assembly.

Background technique

Augment Reality (AR) can integrate the virtual world and the real world on the screen. It achieves a sensory experience that surpasses and increases reality through the real-time superposition of multi-sensory simulation information such as vision and hearing and real environmental information. It has a wide range of application prospects in medical, military and other fields. 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. The existing augmented reality display components use two birefringent crystals to ensure the spherical high-quality display of images on the basis of multi-depth-of-field image display, but the existing augmented reality display components are prone to image dislocation when realizing multi-depth-of-field display. , which easily reduces the clarity of the image display and affects the user's experience.

SUMMARY OF THE INVENTION

In view of this, it is necessary to provide an improved augmented reality display assembly and an augmented reality display device having the same. The augmented reality display assembly can overcome the problem of image misalignment during multi-depth display, and has broad application prospects and excellent economic effect.

The present invention provides an augmented reality display assembly, comprising an image unit, an eyepiece unit, and a refraction unit disposed between the image unit and the eyepiece unit, the refraction unit comprising a first optical switch, a first birefringent crystal, a first a phase retarder and a second birefringent crystal, the first switch is arranged between the image unit and the first birefringent crystal, the phase retardation of the first phase retarder is π/2 and is arranged in the between the first birefringent crystal and the second birefringent crystal;

The refraction unit further includes a first polarizer, a third birefringent crystal and a fourth birefringent crystal, the first polarizer is arranged between the image unit and the first optical switch, and the third birefringent crystal is arranged between the first birefringent crystal and the first phase retarder, and the fourth birefringent crystal is arranged between the second birefringent crystal and the eyepiece unit;

Name the polarization direction of the linearly polarized light output by the first polarizer as the first direction, name the direction perpendicular to the first direction as the second direction, and the crystal optical axis of the first birefringent crystal and the third birefringent crystal. The crystal optical axes of the refracting crystals are all perpendicular to the second direction, and the crystal optical axes of the first birefringent crystals form an angle θ ₁ with respect to the first direction, and the crystal optical axes of the third birefringent crystals Form an angle of -θ ₁ with respect to the first direction;

The crystal optical axis of the second birefringent crystal and the crystal optical axis of the fourth birefringent crystal are both perpendicular to the first direction, and the crystal optical axis of the second birefringent crystal forms θ relative to the second direction ₂ angle, the crystal optical axis of the fourth birefringent crystal forms an angle of −θ ₂ with respect to the second direction.

Further, the θ ₁ is 45°; and/or,

The θ ₂ is 45°.

Further, the refraction unit further includes a second optical switch, the image unit includes a polarization reflector, a second phase retarder and an optical coupler, and the second optical switch is arranged between the fourth birefringent crystal and the polarization Between the reflectors, the second phase retarder is arranged between the polarization reflector and the optical coupler and delays the phase of the polarized light transmitted between the polarization reflector and the optical coupler.

Further, the phase delay of the phase retarder is π/4.

Further, the refraction unit further includes a second polarizer, and the second polarizer is disposed between the second optical switch and the polarizing reflector.

Further, the first polarizer is a polarizer; and/or,

The second polarizer is a polarizer.

Further, the brightness of the image unit is more than 5000 nits; and/or,

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

Further, 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%.

Further, the resolution of the image unit is above 1080P.

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

The present invention adjusts the optical axis positions of the first birefringent crystal, the second birefringent crystal, the third birefringent crystal and the fourth birefringent crystal, so that the images on different birefringent crystal units are symmetrically distributed, so that the superimposed images are It can maintain consistency, thereby eliminating image dislocation, improving image clarity, and has broad application prospects and extremely high economic value.

Description of drawings

FIG. 1 is a schematic structural diagram of an augmented reality display assembly in an embodiment of the present invention;

Fig. 2 is a schematic diagram of the optical path after adding a compensation surface to the eyepiece unit;

Fig. 3 is the MTF curve of the display image at the first depth of field;

Fig. 4 is the distortion grid showing the image at the first depth of field;

Fig. 5 is the MTF curve of the display image at the second depth of field;

FIG. 6 is a distortion grid showing the image at the second depth of field;

Fig. 7 is the optical path schematic diagram of the first birefringent crystal shown in Fig. 1;

8 is a schematic diagram of the optical path of the second birefringent crystal shown in FIG. 1;

FIG. 9 is a schematic diagram of the optical path of the first phase retarder shown in FIG. 1;

10 is a schematic diagram of the optical path of the first birefringent crystal and the third birefringent crystal shown in FIG. 1;

11 is a schematic diagram of the optical path of the second birefringent crystal and the fourth birefringent crystal shown in FIG. 1;

FIG. 12 is a schematic structural diagram of an augmented reality display assembly in another embodiment of the present invention.

Description of main component symbols

The following specific embodiments will further illustrate the present invention in conjunction with the above drawings.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to 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.

It should be noted that when a component is referred to as being "mounted on" another component, it can be directly mounted on the other component or there may also be an intervening 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 co-existing centered component. When a component is said to be "fixed" to another component, it may be directly fixed to the other component or there may also be an intervening component.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention. As used herein, the term "or/and" includes any and all combinations of one or more of the associated listed items.

Please refer to FIG. 1 , which is a schematic structural diagram of an augmented reality display assembly 100 in an embodiment of the present invention. The augmented reality display assembly 100 is for viewing by a user, and is used to display image information projected into the user's eyes.

In this embodiment, the augmented reality display assembly 100 is applied to wearable augmented reality glasses (not shown), and the augmented reality display assembly 100 is used as a lens of the augmented reality glasses, and the user wears the augmented reality glasses and observes the augmented reality display assembly 100 to observe virtual environment information and real environment information.

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

The augmented reality display assembly 100 includes an image unit 10, an eyepiece unit 20 and a refraction unit 30. The refraction unit 30 is located between the image unit 10 and the eyepiece unit 20; the image unit 10 is used for displaying image information for the user to observe, and the eyepiece unit 20 is used for The image light rays refracted by the refraction unit 30 are collected and transmitted to the human eye for imaging. The refraction unit 30 is used to selectively refract the image light rays provided by the image unit 10 .

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

Specifically, the image unit 10 is a display, which can be a CRT display, an LCD display, a PDP display or an OLED display.

In this embodiment, considering the comprehensive performance and cost advantages, the image unit 10 in this embodiment selects a 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. The product competitiveness is better, and the user experience is relatively better.

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

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

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 either one or multiple.

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

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

The natural light containing image information emitted from the image unit 10 is converted into linearly polarized light under the polarization of the first polarizer 31 , and then forms different polarization directions under the adjustment of the first optical switch 32 . Under the action of different refraction of the polarized light in different polarization directions by the refracting crystal 33, an image display with double depth of field is formed.

Specifically, the first polarizer 31 can convert light into polarized light in a natural light state, which utilizes the anisotropy of specific materials in optical properties to polarize natural light.

In this embodiment, the first polarizer 31 uses a polarizer to polarize the natural light containing image information emitted by the image unit 10 . The first polarizer 31 may use a microcrystalline polarizer such as a tourmaline wafer, or Molecular polarizers such as wire grid polarizers are used.

It can be understood that, in other embodiments, the first polarizer 31 may also use other types of polarizers other than polarizers such as a polarizing beam splitter prism, as long as this type of polarizer can polarize image information That's it.

The first optical switch 32 is connected to the first polarizer 31 for adjusting the polarization direction of the optical signal output by the first polarizer 31 . When the first optical switch 32 is turned on, the first optical switch 32 acts on the first polarizer 31 ; when the first optical switch 32 is turned off, the first optical switch 32 has no adjustment effect on the optical signal output by the first polarizer 31 .

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

It can be understood that, in other embodiments, the first optical switch 32 can also adopt other types of optical switch elements such as electro-optic switches, thermo-optic switches, acousto-optic switches, micro-machine optical switches, and traditional mechanical optical switches, as long as the The first optical switch 32 can adjust the direction of the first polarizer 31; the response time and light transmittance of the first optical switch 32 can be selected according to the actual working conditions, for example, the response time of the first optical switch 32 is set at For more than 10 milliseconds, the light transmittance of the first optical switch 32 is set to a range of less than 90%.

The first birefringent crystal 33 is located on the optical path between the first optical switch 32 and the eyepiece unit 20, and is used to refract polarized light; the first birefringent crystal 33 has different refractive indices for linearly polarized light in different polarization directions, and the first birefringent crystal 33 has different refractive indices. The mutual cooperation between the birefringent crystal 33 and the first optical switch 32 can make the applied image light rays have different transmission directions.

In this embodiment, the first birefringent crystal 33 is a birefringent crystal prism; the first birefringent crystal 33 is a birefringent crystal prism, which can make the incident surface of the light on the birefringent crystal prism and the optical axis of the birefringent crystal prism And the exit surfaces are parallel to each other. Linearly polarized lights with different polarization directions only have different refractive indices when passing through the first birefringent crystal 33 , and the chief rays are still in a state of overlapping and not in position, and no additional aberrations will be generated.

Further, the refractive index of the first birefringent crystal 33 for O light is 1.6585, and the refractive index for E light is 1.4865.

It can be understood that in other embodiments, the first birefringent crystal 33 can also have other shapes other than the birefringent crystal prism, as long as the shape and type of the first birefringent crystal 33 can be adjusted to the first optical switch 32 The linearly polarized light can be refracted; the first birefringent crystal 33 can also use other refractive indices other than the above-mentioned refractive indices for different polarized lights (such as O light or E light), as long as the first birefringent crystal 33 has different The refractive index of the polarized light in the polarization direction may be different.

In actual use, considering that the first optical switch 32 needs to constantly switch its own switching state, the first optical switch 32 preferably has a high response frequency, so that the first optical switch 32 has a sufficient response speed to switch its own On and off state and adapt to different display requirements of the image unit 10.

The following briefly explains the display principle of the augmented reality display assembly 100 with multiple depths of field:

After the image light generated by the image unit 10 passes through the first polarizer 31 in the refraction unit 30, only linearly polarized light in a certain characteristic direction (such as ordinary light, referred to as O light) will remain; when the first optical switch 32 is turned on, the line After being adjusted by the first optical switch 32, the polarized light (O light) will be converted into linearly polarized light (eg, extraordinary light, referred to as E light for short) in another polarization direction. When the first optical switch 32 is turned off, the first optical switch 32 does not change the polarization direction of the linearly polarized light, and the linearly polarized light (O light) directly enters the first birefringent crystal 33;

The first birefringent crystal 33 has different refractive indices for linearly polarized light in different directions; when the first optical switch 32 is turned on, the first birefringent crystal 33 refracts the O light at the first refraction angle, and the image in the form of O light The light is then converged by the eyepiece unit 20 to the human eye, so as to obtain an image that can be observed by the user and has a first depth of field; when the first optical switch 32 is turned off, the first birefringent crystal 33 refracts at the second angle of refraction. The E light is refracted, and the image light in the form of E light is then converged to the human eye through the converging action of the eyepiece unit 20, so as to obtain an image that can be observed by the user and has a second depth of field, thereby completing the augmented reality display assembly 100 pairs. Depth of field display process.

Further, when the first optical switch 32 is continuously refreshed at an appropriate frequency, the depth of field perceived by the human eye can be between the first depth of field and the second depth of field, so that the optical parameter of depth of field is between the first depth of field and the second depth of field. Controllable adjustment in depth of field.

It should be noted that the present invention does not limit the first optical switch 32 to only adjust the direction of the O light to the E light. It can be understood that, in other embodiments, the first optical switch 32 can also realize the adjustment of the direction of the E light to the O light.

In the augmented reality display assembly 100 provided by the present invention, a first polarizer 31 , a first optical switch 32 and a first birefringent crystal 33 are arranged between the image unit 10 and the eyepiece unit 20 , and the first birefringent crystal 33 is used for different polarization directions. The different refraction effects of the polarized light on the surface can form images with different depths of field, which can present virtual information at any depth, solve the conflict of adjustment and convergence, not only improve the user experience, but also better fit the observation habits of the human eye. It can avoid adverse reactions such as fatigue, nausea and vomiting of users after long-term observation, and has a wide application prospect.

In an embodiment of the present invention, the refraction unit 30 further includes a projection unit 34 , the projection unit 34 is located between the first birefringent crystal 33 and the eyepiece unit 20 , and the projection unit 34 is used to transmit the first birefringent crystal 33 through the projection unit 34 . The linearly polarized light is transmitted into an enlarged relay real image, and the projection unit 34 utilizes its own relay amplification effect so that the image signal output by the refraction unit 30 can be transmitted to the eyepiece unit 20 more clearly, so that the refraction unit 30 and the eyepiece unit 20 are connected. The transmission loss between the two is reduced, and the image transmission over a longer distance can be realized.

Further, the projection ratio of the projection unit 34 is preferably less than 1.6, so as to reduce the compactness of the projection unit, effectively reduce the spatial scale of the entire assembly and reduce the space of the optical path, leaving more room for industrial design and making it more ergonomic. study.

In this embodiment, the projection unit 34 includes four lenses, and the eyepiece unit 20 includes two transflective lenses. The data of the equivalent optical path are shown in Table 1:

Table 1 Equivalent Optical Path Data Sheet

Please also refer to FIG. 2 . FIG. 2 is a schematic diagram of the optical path of the eyepiece unit 20 after the compensation surface is added. The function of adding the compensation surface to the eyepiece unit 20 is to make the picture of the real world not distorted when the human eye views the real world through the eyepiece unit.

Please refer to Fig. 3 to Fig. 6 together. Fig. 3 is the MTF curve showing the image at the first depth of field, Fig. 4 is the distortion grid showing the image at the first depth of field, and Fig. 5 is the graph showing the image at the second depth of field. MTF curve, Figure 6 shows the distortion grid of the image at the second depth of field.

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

In one embodiment of the present invention, the augmented reality display assembly 100 is further provided with a control unit (not shown in the figure), and the control unit is communicatively connected to the first optical switch 32 and the image unit 10 through a medium such as a wire, and is used for synchronously controlling the first optical switch 32 and the image unit 10 . An optical switch 32 and the operating state of the image unit 10, and control the opening and closing of the first optical switch 32 according to the depth of field that the image unit 10 needs to display. Integrating the control unit inside the augmented reality display assembly 100 can improve the integration degree of the whole system and help to realize the control function of the whole system.

It can be understood that, in other embodiments, the control unit can also be arranged outside the augmented reality display assembly 100, that is, the control unit is arranged outside the augmented reality display assembly 100 as an environmental element, as long as the control unit can communicate with the first optical switch 32 and the image unit 10 are communicatively connected to coordinately control the operating states of the first optical switch 32 and the image unit 10 .

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 higher, and the brightness of the image unit 10 is preferably 5000 nits or higher. Setting the resolution and brightness of the image unit 10 to a higher level helps to improve the fidelity of the image information display and the user experience, so that the virtual image information superimposed on the real image information has a higher fidelity degree.

In one embodiment of the present invention, in order to ensure the user's experience and take into account the image display with dual depths of field, the refresh rate of the image unit 10 is 120 Hz or more (twice or more than 60 Hz for a single depth of field), so that the user can observe no flicker; and/or,

The extinction ratio of the first polarizer 31 is more than 10000:1, so that the polarized light polarized by the first polarizer 31 will not have o light and e light at the same time, so as to ensure that the image observed by the user through the eyepiece unit 20 does not exist. There are two depths at the same time, avoiding image crosstalk and improving imaging quality.

In an embodiment of the present invention, in order to reduce the thickness of the first birefringent crystal 33, the difference in the refractive index of the first birefringent crystal 33 for o light or e light is preferably greater than 0.2, so that the first birefringence is reduced when refraction is reduced. The requirement of the thickness of the crystal 33 further reduces the system load.

In an embodiment of the present invention, in order to improve the user's field of vision, the eyepiece unit 30 in the present invention includes a lens 21, and the lens 21 is an aspherical mirror, and its surface equation is:

Among them, c is the curvature at the vertex of the surface; k is the quadratic surface constant of the surface, and A _i is the i-order aspheric coefficient of the surface.

The 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 situation of strabismus when the user wears it, and the long exit pupil distance can meet the requirements of myopia and hyperopia. The use of mirror wearers, and 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 angle of the lens 21 used in the present invention can reach 50°, which has a wider field of view and better user experience.

Of course, the augmented reality display assembly 100 may also be equipped with various functional elements to improve user experience. For example, an inertial measurement unit (IMU) may also be integrated on the augmented reality display assembly 100, and the control unit controls the The inertial measurement unit thus detects the pose of the whole machine, further improving the user experience.

When the conventional augmented reality display assembly uses the first birefringent crystal 33 to display images with multiple depths of field, since the birefringent crystal itself has different adjustment rules for different linearly polarized lights, it will be difficult to simultaneously display the image quality of itself during image display. ensure.

For example, the refractive index of the birefringent crystal to O light does not change with the incident angle of the O light. The refractive index of the birefringent crystal to the O light is constant, and it will show a "spherical mirror" imaging effect when displaying images; The refractive index of the E light will change with the incident angle of the E light, and the refractive index at its own sagittal and meridional planes will be different, which will present a "cylindrical mirror" imaging effect when displaying images. This results in different imaging effects at different depths of field, and the user will switch back and forth between different images with different imaging effects when observing, which affects the normal observation of the images.

The augmented reality display assembly 100 provided by the present invention is provided with two birefringent crystals and a phase retarder, so that the imaging effects at different depths of field are consistent, thereby overcoming the problem of image quality degradation caused by using a single birefringent crystal.

Specifically, the refraction unit 30 further includes a second birefringent crystal 35 and a first phase retarder 36, the first phase retarder 36 is located between the first birefringent crystal 33 and the second birefringent crystal 35, and the second birefringent crystal 36 35 is located between the first phase retarder 36 and the eyepiece unit 20 . The phase retardation of the first phase retarder 36 is π/2, which is used to convert the linearly polarized light into linearly polarized light perpendicular to the original vibration direction.

When the first optical switch 32 is turned off, the linearly polarized light formed after the polarizer 31 is polarized is not converted by the first optical switch 32, and the linearly polarized light in the initial state is formed by the first birefringent crystal 33 at this time. The output mode of "spherical imaging"; the polarization direction of the linearly polarized light after passing through the first phase retarder 36 is perpendicular to the initial state, and the output mode of "spherical imaging" is still formed through the second birefringent crystal 35 at this time; in general, The refraction unit 30 forms an output mode of "spherical imaging" after the first optical switch 32 is turned off;

When the first optical switch 32 is turned on, the linearly polarized light formed after the polarizer 31 is polarized is converted by the first optical switch 32. At this time, the converted linearly polarized light is formed by the first birefringent crystal 33. The output mode of "cylindrical imaging"; the linearly polarized light is converted into linearly polarized light with the same vibration direction as the initial state through the first phase retarder 36, and then the output mode of "cylindrical imaging" is still formed through the second birefringent crystal 35 , but the cylinders formed by the first birefringent crystal 33 and the second birefringent crystal 35 are perpendicular to each other; in general, the refraction unit 30 forms an output mode of "spherical imaging" after the first optical switch 32 is turned on.

Please refer to FIGS. 7 to 9 together. FIG. 7 is a schematic diagram of the optical path of the first birefringent crystal 33 shown in FIG. 1 , FIG. 8 is a schematic diagram of the optical path of the second birefringent crystal 35 shown in FIG. 1 , and FIG. A schematic diagram of the optical path of the first phase retarder 36 is shown.

The light entering the first birefringent crystal 33 passes through the first birefringent crystal 33 along the propagation direction 301; wherein, the polarization direction of the linearly polarized light polarized by the first polarizer 31 is named the first direction 302, and the vertical The direction in the first direction 302 is named as the second direction 303, and the crystal optical axis 331 of the first birefringent crystal 33 is set to lie in the plane formed by the propagation direction 301 and the first direction 302, that is, the first birefringent crystal The crystal optical axis 333 of 33 is preferably perpendicular to the second direction 303 .

The light entering the second birefringent crystal 35 passes through the second birefringent crystal 35 along the propagation direction 301; wherein, the polarization direction of the linearly polarized light polarized by the first polarizer 31 is named as the first direction 302, and the vertical The direction in the first direction 302 is named as the second direction 303, and the crystal optical axis 351 of the second birefringent crystal 35 is set to lie in the plane formed by the propagation direction 301 and the second direction 303, that is, the second birefringent crystal The crystal optical axis 351 of 35 is preferably perpendicular to the first direction 302 . In this way, the image imaging quality is better.

Further, the crystal optical axis 331 of the first birefringent crystal 33 is perpendicular to the second direction 303 and forms an angle of 45° with the first direction 301, and the crystal optical axis 351 of the second birefringent crystal 35 is preferably perpendicular to the first direction 302. And it forms an angle of 45° with the second direction 303 . In this way, it has the best image imaging quality.

Further, the optical axis 361 of the first phase retarder 36 is perpendicular to the propagation direction 301 of the light, and forms an angle of 45 degrees with both the first direction 302 and the second direction 303 , thereby completing the limit delay function.

The present invention utilizes the first birefringent crystal 33, the second birefringent crystal 35, and the first phase retarder 36 disposed between the first birefringent crystal 33 and the second birefringent crystal 35 to realize the output of spherical imaging images with multiple depths of field In this way, it can ensure that the quality of the image output is maintained in the high-quality output mode of spherical surface, the image distortion is less, and the imaging clarity is improved.

Considering that although the crystal optical axis 331 of the first birefringent crystal 33 can be perpendicular to the second direction 303, although the crystal optical axis 351 of the second birefringent crystal 35 can be perpendicular to the first direction, due to the The crystal optical axis 331 is not parallel to the first direction 302, and the crystal optical axis 351 of the second birefringent crystal 35 is not parallel to the second direction 303, which leads to the use of the first birefringent crystal 33 and the second birefringent crystal 35. When imaging and observing at a fixed point, the image positions cannot be consistent, and the images at the two depths of field are misaligned.

Please refer to FIGS. 10 to 11 together. FIG. 10 is a schematic diagram of the optical paths of the first birefringent crystal 33 and the third birefringent crystal 37 shown in FIG. 1 , and FIG. 11 is the second birefringent crystal 35 and the fourth birefringent crystal 35 shown in FIG. Schematic diagram of the optical path of the birefringent crystal 38 .

In an embodiment of the present invention, in order to overcome the problem of image dislocation at two depths of field, the refraction unit 30 in an embodiment of the present invention is further provided with a third birefringent crystal 37 and a fourth birefringent crystal 38 . The third birefringent crystal 37 is located between the first birefringent crystal 33 and the first phase retarder 36 , and the fourth birefringent crystal 38 is disposed between the second birefringent crystal 35 and the projection unit 34 .

In order to eliminate the image dislocation, the crystal optical axis 331 of the first birefringent crystal 33 and the crystal optical axis 371 of the third birefringent crystal 37 are set to be both perpendicular to the second direction 303, and the crystal optical axis of the first birefringent crystal 33 331 forms an angle of θ ₁ with the first direction 302, and the crystal optical axis 371 of the third birefringent crystal 37 forms an angle of −θ ₁ with the first direction 302;

The crystal optical axis 351 of the second birefringent crystal 35 and the crystal optical axis 381 of the fourth birefringent crystal 38 are set to be both perpendicular to the first direction 302, and the crystal optical axis 351 of the second birefringent crystal 35 is perpendicular to the second direction. 303 forms an angle of θ ₂ , and the fourth birefringent crystal 38 forms an angle of −θ ₂ with the second direction 303 . At this time, the images at the two depths of field can be kept consistent in the superimposed images due to the positional relationship of the symmetrical distribution, thereby eliminating the dislocation of the images and improving the clarity of the images.

Further, θ ₁ is set to 45°, at this time, the image symmetry of the first birefringent crystal 33 and the third birefringent crystal 37 during refraction is the best, and the dislocation elimination effect of the image is the best; and/or,

When θ ₂ is set to 45°, the image symmetry of the second birefringent crystal 35 and the fourth birefringent crystal 38 during refraction is the best, and the dislocation elimination effect of the image is in the best state.

In the present invention, by adjusting the optical axis positions of the first birefringent crystal 33, the second birefringent crystal 35, the third birefringent crystal 37 and the fourth birefringent crystal 38, the images on different birefringent crystal units are symmetrically distributed, thereby making The superimposed images can be kept consistent, thereby eliminating image misalignment and improving image clarity.

Please also refer to FIG. 12 . FIG. 12 is a schematic structural diagram of an augmented reality display assembly 100 according to another embodiment of the present invention.

In an embodiment of the present invention, considering the insufficient light intensity of linearly polarized light for imaging, in order to compensate for the loss of light intensity and display brightness, the augmented reality display assembly 100 in this embodiment is located at the position of the first optical switch 32 . On the basis, an additional optical switch is set up, and two optical switches with the same switching state and a polarized reflector are used to make up for the loss of light intensity.

Specifically, the augmented reality display assembly 100 further includes a second optical switch 39, which is located between the projection unit 34 and the fourth birefringent crystal 38; the second optical switch 39 has the same working state as the first optical switch 32 , that is, the second optical switch 39 and the first optical switch 32 are in an on or off state at the same time, and the working states of the two are in the same state of coupling under the control of the control unit.

As far as the structure of the second optical switch 39 itself is concerned, it can adopt a conventional structure. In this embodiment, considering the interchangeability of the entire assembly, both the second optical switch 39 and the first optical switch 32 use liquid crystal light valves; The light transmittance of the optical switch 39 is set to a range greater than 90%.

It can be understood that, in other embodiments, the second optical switch 39 may also adopt other types of optical switch elements such as electro-optic switches, thermo-optic switches, acousto-optic switches, micro-machine optical switches, and traditional mechanical optical switches, as long as the The optical switch element can adjust the polarization direction; the response time and light transmittance of the second optical switch 39 can be selected according to the actual working conditions. For example, the response time of the second optical switch 39 is set to more than 10 milliseconds, and the The light transmittance of 39 is set in the range of less than 90%.

The eyepiece unit 20 in the augmented reality display assembly 100 further includes a second phase retarder 22 and an optical coupler 23, the mirror 21 in the eyepiece unit 20 adopts a polarization reflector, and the second phase retarder 22 is located in the polarization reflector and the optical coupler. between 23. The phase retardation of the second phase retarder 22 is π/4, which is used to delay the phase of linearly polarized light; the optical coupler 23 is used to reflect linearly polarized light, and the polarized reflector is used to selectively reflect or transmit polarized light, which can Allows polarized light perpendicular to the original polarization direction to pass through and reflects polarized light in other polarization directions.

The following explains the display principle of the augmented reality display assembly 100 with higher brightness:

The working states of the first optical switch 32 and the second optical switch 39 are the same. When both the first optical switch 32 and the second optical switch 39 are in the off state, the linearly polarized light polarized by the first polarizer 31 will not be An optical switch 32 and a second optical switch 39 change their polarization directions, and are reflected when projected on the polarization reflector, thereby passing through the second phase retarder 22 and realizing a phase delay of π/4; After the phase delay of π/4, it is reflected by the optical coupler 23, passes through the second phase retarder 22 again, and realizes the phase delay of π/4 again; the linearly polarized light is superimposed by the phase delay of π/4 twice to realize a total of π /2 phase retardation, at this time, the linearly polarized light is transformed into linearly polarized light perpendicular to the original vibration direction, thus passing through the polarizing reflector, and imaging in the human eye;

When both the first optical switch 32 and the second optical switch 39 are in the on state, the linearly polarized light polarized by the first polarizer 31 will recover after the first optical switch 32 and the second optical switch 39 undergo two polarization conversions. To its own polarization direction, it is reflected when projected on the polarizing reflector, thereby passing through the second phase retarder 22 and realizing a phase delay of π/4; the linearly polarized light is reflected by a phase delay of π/4 The coupler 23 reflects, passes through the second phase retarder 22 again and realizes the phase delay of π/4 again; the linearly polarized light achieves a total phase delay of π/2 after the phase delay of π/4 is superimposed twice. The polarized light is converted into linearly polarized light perpendicular to the original vibration direction to pass through the polarized reflector and image in the human eye.

The augmented reality display assembly 100 provided by the present invention uses the second phase retarder 22 and the optical coupler 23 to change the type of polarized light used for imaging, and improves the brightness of the image display, which can theoretically be increased to 4% of the brightness of the traditional display image It has high application value and broad application prospects.

Further, considering that the optical rotation capabilities of the first optical switch 32 and the second optical switch 39 are limited, the first optical switch 32 and the second optical switch 39 do not have sufficient capabilities to completely convert the linearly polarized light to the initial state after two transformations. , causing the optical signal output by the second optical switch 39 to have two linearly polarized lights with different polarization directions at the same time, which will lead to a decrease in the contrast of the image display; A second polarizer 391 is also provided in the center, and the second polarizer 391 is located between the second optical switch 39 and the projection unit 34 .

The second polarizer 391 plays the role of re-polarization, so that the second optical switch 39 filters out the linearly polarized light of the redundant polarization direction that can be completely converted, and only leaves the linearly polarized light with the same polarization direction as the original, thereby Ensure the contrast of the image display.

Further, the first polarizer 31 adopts a polarizer; and/or,

The second polarizer 391 also uses a polarizer.

Since the polarizing ability of the polarizer is stable, it is conducive to the realization of the polarizing function of the entire component, and it also has a great advantage in cost performance.

It can be understood that in other implementation manners, the phase delay of the second phase retarder 22 may also adopt other angles other than π/4, as long as the sum of the phase delays accumulated on the front and the back of the second phase retarder 22 is π/2 That's it.

The present invention further provides an augmented reality display device (not shown), the augmented reality display device comprising a wearable device body (not shown) and an augmented reality display assembly 100 disposed on the device body. The augmented reality display device provided by the present invention uses the augmented reality display assembly 100 to make the imaging mode consistent when displaying images with multiple depths of field, and can maintain a high-quality spherical mirror imaging mode.

In the present invention, by adjusting the optical axis positions of the first birefringent crystal 33, the second birefringent crystal 35, the third birefringent crystal 37 and the fourth birefringent crystal 38, the images on different birefringent crystal units are symmetrically distributed, thereby making The superimposed images can be kept consistent, thereby eliminating the dislocation of the images, improving the clarity of the images, and having broad application prospects and extremely high economic value.

The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity, all possible combinations of the technical features in the above-described embodiments are not described. However, as long as there is no contradiction between the combinations of these technical features, All should be regarded as the scope described in this specification.

Those skilled in the art should realize that the above embodiments are only used to illustrate the present invention, not to limit the present invention, as long as the above embodiments can be appropriately changed within the spirit and scope of the present invention and variations all fall within the scope of the claimed invention.

Claims (10)

1. An augmented reality display assembly comprises an image unit, an ocular unit and a refraction unit arranged between the image unit and the ocular unit, wherein the refraction unit comprises a first optical switch, a first birefringent crystal, a first phase retarder and a second birefringent crystal, the first optical switch is arranged between the image unit and the first birefringent crystal, the phase delay of the first phase retarder is pi/2 and is arranged between the first birefringent crystal and the second birefringent crystal;

the refraction unit is characterized by further comprising a first polarizer, a third birefringent crystal and a fourth birefringent crystal, wherein the first polarizer is arranged between the image unit and the first optical switch, the third birefringent crystal is arranged between the first birefringent crystal and the first phase retarder, and the fourth birefringent crystal is arranged between the second birefringent crystal and the eyepiece unit;

naming the polarization direction of linearly polarized light output by the first polarizer as a first direction, naming the direction perpendicular to the first direction as a second direction, wherein the crystal optical axis of the first birefringent crystal and the crystal optical axis of the third birefringent crystal are both perpendicular to the second direction, and the crystal optical axis of the first birefringent crystal forms theta relative to the first direction₁An angle, a crystal optic axis of the third birefringent crystal forming-theta with respect to the first direction₁An angle;

the crystal optical axis of the second birefringent crystal and the crystal optical axis of the fourth birefringent crystal are both perpendicular to the first direction, and the crystal optical axis of the second birefringent crystal forms theta relative to the second direction₂An angle, a crystal optic axis of the fourth birefringent crystal forming- θ with respect to the second direction₂And (4) an angle.

2. As claimed in claimThe augmented reality display assembly of claim 1, wherein θ is₁Is 45 degrees; and/or the presence of a catalyst in the reaction mixture,

theta is described₂Is 45 degrees.

3. The augmented reality display assembly of claim 2, wherein the refraction unit further comprises a second optical switch, the image unit comprising a polarizing reflector, a second phase retarder disposed between the fourth birefringent crystal and the polarizing reflector, and an optical coupler, the second phase retarder disposed between the polarizing reflector and the optical coupler and retarding a phase of polarized light transmitted between the polarizing reflector and the optical coupler.

4. The augmented reality display assembly of claim 3, wherein the phase retarder has a phase retardation of pi/4.

5. The augmented reality display assembly of claim 4, wherein the refraction unit further comprises a second polarizer disposed between the second optical switch and a polarizing reflector.

6. The augmented reality display assembly of claim 5, wherein the first polarizer is a polarizer; and/or the presence of a catalyst in the reaction mixture,

the second polarizer is a polarizing plate.

7. The augmented reality display assembly of claim 1, wherein the brightness of the image cell is 5000 nits or more; and/or the presence of a catalyst in the reaction mixture,

the refresh rate of the picture cells is above 120 Hz.

8. The augmented reality display assembly of claim 1, wherein the response time of the light switch is less than 10 milliseconds; and/or the presence of a catalyst in the reaction mixture,

the light transmittance of the optical switch is greater than 90%.

9. The augmented reality display assembly of claim 1, wherein the resolution of the image unit is 1080P or greater.

10. An augmented reality display device comprising an augmented reality display assembly, wherein the augmented reality display assembly is the augmented reality display assembly of any one of claims 1 to 9.

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