WO2021218454A1 - Lens unit and ar device comprising same - Google Patents

Abstract

A lens unit, comprising a substrate (1) made of an optical waveguide material, and having a first optical plane, a second optical plane opposite to the first optical plane, a first diffraction grating area (2), and a second diffraction grating area (3). A diffraction grating area provided on the first optical plane of the substrate (1) constitutes the first diffraction grating area (2), and a diffraction grating area provided on the second optical plane of the substrate (1) opposite to the first optical plane constitutes the second diffraction grating area (3). The first diffraction grating area (2) has a consistent first grating vector on the first optical plane of the substrate (1), and the second diffraction grating area (3) has a consistent second grating vector on the second optical plane of the substrate (1) opposite to the first optical plane. According to AR glasses comprising the lens unit, the quality of an image inputted into human eyes is improved; compared with a conventional waveguide lens unit, the manufacturing process is simpler, and costs are lower.

Description

Lens unit and AR device including the lens unit Technical field

The invention relates to a lens unit and an AR device including the lens unit.

Background technique

The description here only provides background information related to the present invention, and does not necessarily constitute the prior art.

Augmented Reality (AR) technology is a new technology that "seamlessly" integrates real world information with virtual world information. It combines physical information that is difficult to experience within a certain time and space of the real world. , Through computer and other science and technology, simulation and then superimposed, so that people can get a sensory experience beyond reality. Due to the feature of augmented reality technology superimposing virtual objects or pictures in a real environment, it has shown great application potential in many fields.

The optical waveguide lens (lens unit) is the key core component in the new generation of augmented reality technology. It combines the principle of total reflection waveguide and the diffraction element to replicate and expand the exit pupil in the imaging system. It also has a large field of view and a small Advantages such as volume and small weight. The optical waveguide lens conducts the image light laterally without hindering people from observing the vertical reality picture. Therefore, the waveguide lens has become an inevitable trend in the development of AR technology.

The typical optical waveguide technology is to project the image light source emitted by the microdisplay into the incident grating area of the waveguide sheet through a projection lens. Through the total reflection transmission of the waveguide sheet and the action of the diffraction grating, the entrance pupil light source is replicated and expanded in two directions, creating an expanded exit pupil in the coupling-out grating area, which increases the observation range of the human eye. At present, the representative diffractive optical elements that are more commonly used are two-dimensional cross gratings and butterfly-wing gratings, which are used for coupling in and out of the signal light source on the waveguide chip. The cross grating is a grating with periods in two dimensions. The butterfly-wing grating is provided with a turning grating area on both sides of the coupled grating. Crossed gratings are difficult to prepare, and the degree of freedom of design is also lower than that of butterfly wing gratings (groove depth, tilt, fill factor, etc.). Since the butterfly wing grating has four diffraction grating regions, the tolerance requirements for preparation are relatively high, and the preparation is also more difficult.

In the optical design of the waveguide film, it is often required that the incident light in the coupling and turning area and the outgoing light in the coupling area are kept parallel to transmit the image to the human eye completely and without distortion. This requires the relevant coupling and The vector sum of the gratings in the turning area and the out-coupling area is zero, that is, the sum of the grating vectors of the multiple gratings where light passes through the diffraction is zero. This places very high requirements on the design and preparation accuracy of the grating structure. On the one hand, the design of the grating structure must have a high diffraction efficiency. On the other hand, there must be errors in the preparation of the grating, such as the direction, angle, and depth of the grating line. There will be a certain error if the design is completely matched. This leads to the fact that the sum of all relevant grating vectors of the actually produced waveguide film is not necessarily zero, and the incident light and output light of the waveguide film cannot be kept parallel, and the final image input into the human eye will have aberrations and distortions.

Conventional waveguides use three or more grating structures, including coupling-in grating, turning grating, and coupling-out grating. The vector sum of the three gratings must be zero to ensure that the input light and output light are parallel. However, there will always be Manufacturing tolerances cannot guarantee that the three grating structures manufactured will exactly match the design values.

Summary of the invention

The purpose of the present invention is to provide a lens unit and AR device that can improve the image quality of the input human eye, especially to overcome the defects of the prior art, concisely and effectively enable the emergent light and the incident light to remain completely parallel, and While realizing the integration of coupling in, pupil dilation, and coupling out, compared with the traditional waveguide lens unit, the manufacturing process is simpler and the cost is lower.

Therefore, according to the first aspect of the present invention, a lens unit is provided, including: a substrate made of an optical waveguide material, which has a first optical plane and a second optical plane opposite to the first optical plane; and

The first diffraction grating area and the second diffraction grating area, where the diffraction grating area provided on the first optical plane of the substrate constitutes the first diffraction grating area, and the second diffraction grating area is provided on the substrate opposite to the first optical plane. The diffraction grating area on the optical plane constitutes the second diffraction grating area;

Wherein, the first diffraction grating area has a consistent first grating vector on the first optical plane of the substrate, and the second diffraction grating area has a consistent first grating vector on the second optical plane of the substrate opposite to the first optical plane. The second raster vector.

According to the technical solution of the present invention, the light emitted by the microprojector is diffracted and coupled by two diffraction grating surfaces, diffused and transmitted through multiple total reflections and diffractions, and finally images can be seen in any area of the grating working part. The lens unit according to the present invention has only two grating vectors, that is, the first diffraction grating area has the same first grating vector on the first optical plane of the substrate, and the second diffraction grating area is on the first and second grating vectors of the substrate. An optical plane is opposite to a second optical plane with a consistent second grating vector, so the product design has a high degree of freedom, a simple structure, easy mass production and processing, and high industrial application value.

According to some embodiments of the first aspect of the present invention, the first diffraction grating area provided on the first optical plane of the substrate is a continuous area, and/or the first diffraction grating area provided on the substrate opposite to the first optical plane The second diffraction grating area on the two optical planes is a continuous area.

According to some embodiments of the first aspect of the present invention, the first diffraction grating area is continuous on the entire first optical plane of the substrate, and/or the second diffraction grating area is continuous on the entire second optical plane of the substrate .

According to some embodiments of the first aspect of the present invention, the first diffraction grating area provided on the first optical plane of the substrate is a discontinuous area, and/or the first diffraction grating area provided on the substrate opposite to the first optical plane The second diffraction grating area on the two optical planes is a discontinuous area.

According to some embodiments of the first aspect of the present invention, the first grating vector of the first diffraction grating region is different from the second grating vector of the second diffraction grating region.

According to the present invention, the light can be modulated by at least four gratings on the upper and lower surfaces, and the direction of the output light and the input light can be kept consistent, which improves the image quality of the input human eye. According to some embodiments of the first aspect of the present invention, the incident light is coupled out after being modulated by four gratings in the lens unit.

According to some embodiments of the first aspect of the present invention, the first diffraction grating area provided on the first optical plane of the substrate and the first diffraction grating area provided on the second optical plane of the substrate opposite to the first optical plane The two diffraction grating regions respectively modulate the incident light twice.

According to some embodiments of the first aspect of the present invention, the first diffraction grating area provided on the first optical plane of the substrate and the first diffraction grating area provided on the second optical plane of the substrate opposite to the first optical plane The two diffraction grating regions have the same grating period.

According to some embodiments of the first aspect of the present invention, in the plane where the lens unit is located, the grating groove line of the first diffraction grating area and the grating groove line of the second diffraction grating area have an included angle of 40-90°.

According to some embodiments of the first aspect of the present invention, the grating groove lines of the first diffraction grating region and the grating groove lines of the second diffraction grating region have an included angle of 60°.

According to some embodiments of the first aspect of the present invention, during the diffraction propagation process of the lens unit, the diffraction angle of the diffracted light satisfies the formula:

Where |k _r | represents the amplitude of the target light wave vector, n is the refractive index of the optical waveguide material, λ ₀ is the center wavelength of the image light source, and θ _max is the maximum transmission angle.

According to some embodiments of the first aspect of the present invention, the optical waveguide material constituting the substrate is optical glass or optical resin.

According to some embodiments of the first aspect of the present invention, the first diffraction grating area provided on the first optical plane of the substrate and the first diffraction grating area provided on the second optical plane of the substrate opposite to the first optical plane The two diffraction grating regions include surface relief gratings.

According to some embodiments of the first aspect of the present invention, the first diffraction grating area provided on the first optical plane of the substrate and the first diffraction grating area provided on the second optical plane of the substrate opposite to the first optical plane The two diffraction grating regions include positive gratings, blazed gratings, tilted gratings and/or sinusoidal gratings.

According to some embodiments of the first aspect of the present invention, the first diffraction grating area provided on the first optical plane of the substrate and the first diffraction grating area provided on the second optical plane of the substrate opposite to the first optical plane The two diffraction grating regions at least partially overlap each other on both sides of the substrate.

According to some embodiments of the first aspect of the present invention, in the plane where the lens unit is located, the grating vector of the first diffraction grating region and the grating vector of the second diffraction grating region are axisymmetric.

According to some embodiments of the first aspect of the present invention, the first diffraction grating area provided on the first optical plane of the substrate and the first diffraction grating area provided on the second optical plane of the substrate opposite to the first optical plane The two diffraction grating regions have the same slot line structure.

According to some embodiments of the first aspect of the present invention, the lens unit is a see-through light guide lens unit.

According to some embodiments of the first aspect of the present invention, a coupling and turning area for incident light is provided on the first optical plane and/or on the second optical plane of the substrate.

According to a second aspect of the present invention, an AR device is provided, which includes at least one lens unit described above. According to some embodiments of the second aspect of the present invention, the AR device is AR glasses.

Description of the drawings

The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. In the drawings, unless otherwise specified, the same reference numerals are used to denote the same components. in:

FIG. 1 is a schematic diagram of the structure of a lens unit according to some embodiments of the present invention, in which the image light emitted by the micro projector is transmitted to the human eye through the lens unit;

2 is a schematic diagram of the diffraction transmission of incident light in the lens unit according to some embodiments of the present invention;

Figures 3(a)-(d) respectively show schematic diagrams of the optical paths on the grating interface at different diffraction transmission stages;

Fig. 4 is a three-dimensional schematic diagram of the diffraction transmission process in the waveguide sheet as an example of fourth-order grating modulation;

Figure 5 shows the grating vector k diagram of the diffraction transmission process in the waveguide sheet;

6 is a schematic diagram of the groove line structure of the grating area according to some embodiments of the present invention;

7(a)-(d) are schematic diagrams of grating types according to some embodiments of the present invention;

8 is a structural diagram of the coupling and turning area and the coupling out area of the lens unit according to some embodiments of the present invention. Here, the coupling and turning area are provided in one of the optical planes, where the coupling and turning areas are corresponding The decoupling area is completely enclosed;

9 is a structural diagram of the coupling and turning area and the coupling out area of the lens unit according to some embodiments of the present invention, where a coupling and turning area are respectively provided in the first and second optical planes of the lens unit, Here the coupling-in and turning areas are respectively completely surrounded by the corresponding coupling-out areas;

10 is a structural diagram of the coupling and turning area and the coupling out area of the lens unit according to some embodiments of the present invention, where the coupling and turning area are respectively connected to the corresponding coupling out area parts;

11 is a structural diagram of the coupling and turning area and the coupling out area of the lens unit according to some embodiments of the present invention, where the coupling and turning area and the corresponding coupling out area are not connected;

FIG. 12 is a schematic diagram of AR glasses according to some embodiments of the present invention;

FIG. 13 is a schematic diagram of AR glasses according to some embodiments of the present invention, with a modified appearance of the lens unit;

14 is a schematic diagram of AR glasses according to some embodiments of the present invention, where a separate light guide element is provided;

FIG. 15 is a schematic diagram of AR glasses according to other embodiments of the present invention.

Detailed ways

The concept of the present invention will be further described in detail below with reference to specific embodiments. It should be pointed out that the embodiments listed here are only used to clearly illustrate the inventive concept of the present invention, and should not be construed as limiting the present invention. The technical features of the lens unit and the AR device involved here, as long as they do not violate the laws of nature or technical specifications, can be combined or replaced arbitrarily within the framework of the concept of the present invention, and they are all within the scope of the concept of the present invention.

It should be pointed out that the embodiments shown in the drawings are only used as examples to explain and illustrate the concept of the present invention concretely and vividly. In terms of size and structure, they are neither necessarily drawn to scale nor constitute a limitation to the concept of the present invention.

The directional terms such as up, down, left, right, front, back, front, back, top, bottom, vertical, horizontal, etc., mentioned or may be mentioned in this specification are relative to the structure shown in the respective drawings or The products defined in the normal use state are relative concepts, so they may change accordingly according to their different positions and different use states. Therefore, these or other orientation terms should not be interpreted as restrictive terms.

Through the disclosure given, there is provided a lens unit including a substrate made of an optical waveguide material, which has a first optical plane and a second optical plane opposite to the first optical plane. The lens unit further includes a first diffraction grating area and a second diffraction grating area, wherein the diffraction grating area provided on the first optical plane of the substrate constitutes the first diffraction grating area, and the first diffraction grating area is provided on the substrate and the first optical plane. The diffraction grating area on the opposite second optical plane constitutes a second diffraction grating area. Here, the first diffraction grating region has a consistent first grating vector on the first optical plane of the substrate, and the second diffraction grating region has a consistent first grating vector on the second optical plane of the substrate opposite to the first optical plane. The second raster vector.

That is to say, according to the present invention, the diffraction grating regions on the first optical plane of the substrate all have the same grating vector, that is, the first grating vector, while the diffraction grating region on the first optical plane of the substrate has the same grating vector. The diffraction grating regions on the optical plane all have the same grating vector, that is, the second grating vector. Therefore, the lens unit (hereinafter also referred to as the waveguide sheet) according to the present invention has a total of two grating vectors, which not only can concisely and effectively make the outgoing light and the incident light be completely parallel, but also enables a high degree of freedom in product design. It is simple, easy to mass production and processing, and has high industrial application value.

Fig. 1 is a schematic structural diagram of a lens unit according to some embodiments of the present invention, in which image light emitted by a microprojector 40 is transmitted to the eyes of a person through the lens unit. As shown in FIG. 1, the lens unit includes a substrate 1 made of an optical waveguide material, for example, having a sheet-like or plate-like shape, and forming a diffractive optical waveguide with total reflection. The substrate 1 has a first optical plane and a second optical plane opposite to the first optical plane. As an example, the optical waveguide material constituting the substrate 1 may be optical glass or optical resin.

A first diffraction grating region 2 and a second diffraction grating region 3 are respectively provided on the substrate 1 made of optical waveguide material, wherein the first diffraction grating region 2 is provided on the first optical plane of the substrate 1, and the second diffraction grating region 2 is provided on the first optical plane of the substrate 1. The diffraction grating area 3 is arranged on a second optical plane of the substrate 1 opposite to the first optical plane. With this arrangement, the first diffraction grating region 2 provided on the first optical plane of the substrate 1 and the second diffraction grating region 2 provided on the second optical plane of the substrate 1 opposite to the first optical plane The regions 3 are opposite to each other on both sides of the substrate 1 and preferably overlap at least partially, so that within the grating regions that overlap each other, light is diffracted and propagated between the two oppositely overlapping grating interfaces in the waveguide sheet.

In addition, the first diffraction grating region 2 provided on the first optical plane of the substrate 1 has a first grating vector, and the second diffraction grating region 2 provided on the second optical plane opposite to the first optical plane of the substrate 1 The grating area 3 has a second grating vector, in which the incident light is coupled out after at least four grating modulations in the lens unit. Through this kind of lens unit or waveguide sheet, every time the totally reflected light encounters the grating on the surface of the substrate 1, a part of the light is released into the eye through diffraction, and the remaining part of the light continues to propagate in the waveguide until the next time. Hit the grating on the surface of the waveguide.

In the illustrated embodiment, a diffraction grating working area, namely the first diffraction grating area 2 and the second diffraction grating area 3 are respectively provided on two opposing optical surfaces. Therefore, after the image light emitted by the microprojector 40 is coupled into the lens unit, it is diffused, transmitted and coupled out after multiple total reflections and diffractions in the substrate 1 of the lens unit, and finally can be seen in the working area of the diffraction grating image.

Fig. 2 is a schematic diagram of a diffraction transmission optical path of incident light in a lens unit according to some embodiments of the present invention. Subsequently, in conjunction with the schematic diagram of FIG. 2, the diffraction transmission optical path of the incident light in the lens unit according to some embodiments of the present invention will be described. Here, the image light is at a certain angle with the surface of the waveguide, especially substantially perpendicular to the surface of the waveguide, and is coupled into the lens unit. One of the diffraction grating regions is called the upper surface, and the other diffraction grating region is called the upper surface. For the bottom surface. It should be pointed out that the azimuth relationship assumed here is only used to describe the diffraction transmission optical path, and its principle and process are also applicable to other azimuth relationships, and are also within the scope of recording and disclosure of the present invention.

As shown in FIG. 2, the image light a of the micro projector 40 is at a certain angle with the surface of the waveguide sheet, especially substantially perpendicular to the surface of the waveguide sheet, and is coupled into the lens unit. For example, after being irradiated from the upper surface to the overlapping area of the diffraction grating, the light is diffracted by the lower surface grating, resulting in a diffraction order toward the b direction. At the same time, diffraction through the upper surface grating also produces diffraction orders in the c direction. Since there is a high degree of symmetry in the subsequent transmission of the two diffracted lights of b and c, the subsequent transmission of the b diffracted light is taken as an example.

As shown in the figure, the diffraction order in the b-direction is diffracted by the upper surface grating to produce the diffraction order in the d-direction, and the zero-order diffracted light continues to propagate in the b-direction. The diffracted light in the d direction is diffracted on the lower surface to produce the diffracted light in the e direction, and the zero-order diffracted light continues to transmit in the d direction. The diffracted light in the e-direction is diffracted on the upper surface, and then part of the light f is coupled out, and the zero-order diffracted light continues to transmit in the e direction. The light f is partially coupled out toward the upper surface, and its transmission direction is symmetrical with the incident light a with respect to the normal of the waveguide sheet. The other part of the light f is coupled out toward the lower surface, and its transmission direction is consistent with the incident light a.

Therefore, in some embodiments of the present invention, the incident light is coupled out of the waveguide after undergoing at least four times of grating modulation. During this propagation process, the light transmission directions of the diffraction orders b, d, and e are aligned with the normal of the waveguide surface. The included angle is greater than the critical angle required for total reflection, thereby ensuring lossless transmission inside the waveguide. During the propagation process, the zero-order diffracted light will continue to transmit by total internal reflection, such as spreading in the three directions of b, d, and e. The diffusion is accompanied by diffraction coupling out. For example, the zero-order diffracted light in the d direction passes through g and h. After two diffractions, it is diffracted out again, and the diffusion continues in this way, and finally the light can be coupled out in the entire grating working area, so that the human eye can observe a complete, continuous and clear image at any position of the lens.

In order to clearly illustrate the optical diffraction transmission process of the lens unit according to the present invention, Figures 3(a)-(d) respectively show schematic diagrams of the optical paths on the grating interface at different diffraction transmission stages.

3(a)-(b) show schematic diagrams of the first diffraction grating region and the second diffraction grating region of image light respectively. As shown in Figure 3(a), when the incident light I is normally incident on the grating working area on the upper surface of the waveguide sheet, transmission diffraction orders T _-1 , T ₀ , T _{1 are} generated in the waveguide sheet, and T _{1 is} the direction toward c The diffraction order of the direction. In Figure 3(a), d represents the pitch of the grating, that is, the distance between adjacent grooves, h represents the groove depth, and W represents the protrusion width.

Figure 3(b) _{shows that when the transmission diffraction order T 0 is} incident on the working area of the lower surface grating, three reflection diffraction orders _{of R -1} , R ₀ , and R _{1 are generated, where R -1} is the diffraction order toward the b direction Second-rate.

Figure 3(c) shows a schematic diagram of the intermediate diffraction process in the waveguide sheet. In Fig. 3(c), the upper area is the dielectric waveguide layer, and the lower area is the air. The diffracted light in the direction b is the incident light I in this figure. It is incident on the working area of the upper surface diffraction grating at a spherical angle (θ, φ), resulting in reflection diffraction orders R _-1 , R ₀ , where R _{-1 is} the direction Diffraction order in the d direction. The diffracted light in the d direction is incident on the working area of the lower surface diffraction grating. This process can also be shown in Fig. 3(c). At this time, R _-1 is the diffraction order in the e direction. For the case where the image light is modulated, for example, four times on the grating interface, the diagram in FIG. 3(c) shows the second and third diffraction processes.

Figure 3(d) shows a schematic diagram of image light coupling out of the waveguide sheet. For example, the e-direction diffraction order in Fig. 2 is incident on the working area of the upper surface diffraction grating, and the diffraction process can be represented by Fig. 3(d). At this time, the transmission diffraction order T _-1 and the reflection diffraction order R _-1 and R _{0 are} produced. For the case where the image light is modulated, for example, four times on the grating interface, the diagram in FIG. 3(d) shows the fourth diffraction process.

Taking the fourth-order grating modulation as an example, Fig. 4 shows a three-dimensional schematic diagram of the diffraction transmission process in the waveguide sheet. As shown in the figure, the image light is coupled into the waveguide along the z-axis that is substantially perpendicular to the grating plane, and after passing through the grating regions on the upper and lower surfaces of the waveguide for the first time diffraction, that is, the first grating modulation. Continue the second and third modulations through diffraction and/or total reflection of the upper and lower grating interfaces in the waveguide sheet, and finally use the fourth diffraction on the grating interface to couple out from the waveguide sheet. Obviously, the incident light in the coupling and turning area and the outgoing light in the coupling area are symmetrical with respect to the surface normal of the waveguide sheet, so that the image can be transmitted to the human eye completely and without distortion.

It should be pointed out here that when the incident light coupled into the waveguide sheet and the exit light coupled out of the waveguide sheet are on the same side of the waveguide sheet, the incident light and the exit light are symmetrical with respect to the surface normal of the waveguide sheet. When the incident light coupled into the waveguide sheet and the exit light coupled out of the waveguide sheet are on different sides of the waveguide sheet, the direction of the incident light and the exit light remain the same. In the embodiment of FIG. 4, the incident light a is perpendicular to the surface of the waveguide sheet, and the incident light a and the outgoing light f are on the same side of the waveguide sheet. It should be noted that in Figure 4, since the incident light a coupled into the turning area is perpendicular to the surface of the waveguide, the outgoing light f that is symmetric to the incident light a with respect to the normal to the surface of the waveguide also remains perpendicular to the surface of the waveguide. , That is, the outgoing ray f and the incident ray a remain parallel, and the direction is opposite.

Since the diffraction process contains multiple diffraction orders, the grating can be designed to retain only the required diffraction order, and other diffraction orders have lower energy and can be ignored. The above description only takes the zero-order and first-order diffraction as examples, but the principle and The process is also applicable to other diffraction orders and spatial direction processes, and will not be repeated here.

Therefore, in some embodiments according to the present invention, the incident light is coupled out after being modulated by at least four gratings in the lens unit. The second diffraction grating region 3 on the second optical plane opposite to the first optical plane of the substrate 1 is respectively modulated at least twice. The light modulated by the grating will be described in detail below. The light is diffracted by the grating into zero-order diffracted light and first-order diffracted light. The zero-order diffracted light does not change the component of its light wave vector in the plane of the waveguide, while the first-order diffracted light will The light wave vector of the light is changed, and its component in the plane of the waveguide is also changed. That is to say, in each diffraction of the light, the first-order diffracted light is regarded as being modulated by the grating, while the zero-order light continues to propagate for the next time. Diffraction, and the zero-order diffracted light and the first-order diffracted light are both incident on the two grating areas of the waveguide sheet alternately to be diffracted, thereby realizing the two-dimensional diffusion of the coupled light. It is understandable that the first grating area and the second grating area can also be designed to retain zero-order diffracted light and positive and negative first-order diffracted light, or to retain other diffracted light, which can be determined by those skilled in the art according to their needs. The changes are all within the framework of the technical solution of the present invention.

After the image light emitted by the micro projector 40 is coupled into the lens unit, it is expanded and decoupled in the spatial direction after at least four times of total reflection and diffraction in the substrate 1 of the lens unit. That is to say, through the corresponding light transmission process, two-dimensional pupil dilation in at least two directions is realized at the same time, so that, for example, image light can be coupled out in the entire working area of the diffraction grating.

It should be pointed out that the grating vector is a characteristic parameter of the diffraction grating, which depends on the orientation of the grating and the spatial period of the grating. Specifically, the orientation of the grating vector is the positive and negative direction perpendicular to the grating groove line, and the amplitude of the grating vector is expressed as k=2π/d, where d is the grating period.

The grating vector of the first diffraction grating area of the first optical plane of the lens unit or waveguide sheet can be marked as two components k ₁ = (±D _1x , ±D _1y ), the second diffraction grating area of the second optical plane The raster vector of can be marked as k ₂ =(±D _2x ,±D _2y ).

According to the present invention, the grating period can be set to an appropriate size, so that only the 0th and 1st order diffracted light can be generated when the image light is transmitted and diffused in the waveguide sheet.

The amplitude of the incident light wave vector can be expressed by wavenumber: k _r =2π/λ, where λ represents the wavelength of the diffracted light. _{It has components k rx} and k _{ry in} two directions in the plane of the waveguide sheet. The wave number in the air can be marked as k _r0 , when it enters the medium, the wave number can be expressed as k _rn =k ₀ *n, where n is the refractive index of the material.

The first-order diffracted light diffracted by the incident light k _r0 through the first diffraction grating region of the first optical plane of the waveguide sheet, its light wave vector can be expressed as k _r1 , and the diffraction and turning effect of the grating can be described by a diffraction equation. The vector form in the plane can be expressed as:

(k _r1x , k _r1y )=(k _r0x +D _1x , k _r0y +D _1y )

The diffracted light k _r1 is received by the second diffraction grating region of the second optical plane to produce first-order diffraction, and the generated light wave vector can be expressed as k _r2 , and the same is true:

(k _r2x , k _r2y )=(k _r1x + D _2x , k _r1y + D _2y )

The first diffraction grating area of the first optical plane receives the diffracted light k _r2 again, and the generated diffracted first-order light wave vector can be expressed as k _r3 , and the same is true:

(k _r3x , k _r3y )=(k _r2x + D _1'x , k _r2y + D _1'y)

The second diffraction grating region of the second optical plane receives the diffracted light k _r3 , and the generated diffracted first-order light wave vector can be expressed as k _r4 , and the same principle is as follows:

_{(k r4x, k r4y) =} (k r3x + D 2'x, k r3y + D 2'y) = (k r0x + D 1x + D 2x + D 1'x + D 2'x, k r0y + D _1y +D _2y +D _1'y +D _2'y )

The waveguide film must meet the conditions of achromatic imaging, that is, after the image light of different wavelengths is diffused and transmitted by the waveguide film and finally coupled out, the direction of the emitted light is consistent with the direction of the incident light. In other words, the number of the incident light _(k r0x, k r0y) and the exit wave number _(k r4x, k r4y) light waves are:

_{(k r0x, k r0y) =} (k r4x, k r4y)

Therefore, the grating vector of the waveguide must satisfy:

D _1x + D _2x + D _1'x + D _2'x = D _1y + D _2y + D _1'y + D _2'y = 0

Due to the relationship between the grating in the first optical plane area of the waveguide sheet:

D _1x = -D _1'x , D _1y = -D _1'y

The grating in the second optical plane area has a relationship:

D _2x = -D _2'x , D2y = -D _2'y

Therefore must be able to satisfy the achromatic imaging condition _{(k r0x, k r0y) =} (k r4x, k r4y). Since the grating vectors k ₁ and k ₂ depend on the grating period and have nothing to do with the light wavelength, according to the technical solution proposed by the present invention, the grating vector satisfies this condition, and any wavelength also satisfies the achromatic imaging condition.

Fig. 5 shows the grating vector k diagram of the diffraction transmission process. The image light emitted by the microprojector 40 is, for example, diffracted twice into the waveguide sheet in the overlapping area of the grating, and the light turning effect generated by the two diffractions can be expressed by the superposition of two coupled grating vectors: k _incouple1 and k _incouple2 . The coupled light passes through a number of total reflections and two (or more than two) decoupling diffractions to couple out of the waveguide. The effect of this grating decoupling to deflect light can be expressed by the superposition of two decoupled grating vectors: k _decouple1 and k _decouple2 . The sum of the above-mentioned four grating vectors is equal to or close to zero, that is, lower than a certain threshold. Therefore, the angle at which the light is coupled out of the waveguide is basically unchanged, that is, it is consistent with the coupled light (or is a negative value), so that the image Can spread and transmit.

In the illustrated embodiment, since the periods on the two grating surfaces remain constant, there is a relationship: |k _incouple1 |=|k _decouple1 |, |k _incouple2 |=|k _decouple2 |, that is, each grating surface corresponds to The coupled grating vector and the decoupled grating vector are equal in magnitude and opposite in direction. Therefore, the vector superposition graph just encloses a parallelogram, especially a rhombus, and the grating vector returns to the origin, ensuring that the vector sum is zero. Through these measures, the problem of image quality degradation caused by the non-zero vector sum in the traditional technology and waveguide structure is avoided, and the requirements for the design and manufacture of the lens unit are reduced.

In some other embodiments, the grating vector k pattern may not be a rhombus, but a conventional parallelogram. In these solutions, the sum of the four grating vectors can still be guaranteed to be zero, because the light is diffracted four times in the waveguide. It will be diffracted twice by the same grating, that is, the opposite sides of the grating vector k are always parallel and equal in size (that is, the coupled grating vector and the decoupled grating vector), so the vector sum must be zero. Furthermore, it is ensured that the incident light and the outgoing light of the waveguide sheet are parallel, and the image quality of the input human eye is ensured.

In some embodiments, the diffraction grating is designed as a coupling element, and it must be ensured that the diffraction angle of the generated target diffracted light is limited between the total reflection angle and the maximum transmission angle (θ _max ). This limitation can be based on the following physical relationship Expression:

Among them, |k _r | represents the amplitude of the target light wave vector, n is the refractive index of the optical material, and λ ₀ is the center wavelength of the image light source. The left side of the inequality represents the lower limit of the total reflection angle on the light wave vector, and the right side represents the upper limit of the maximum transmission angle of the waveguide sheet on the light wave vector. In some embodiments, the maximum transmission angle θ _max can be as high as 75°.

Specifically, the light wave vector |k _r | needs to be smaller than the radius of the outer circle in FIG. 5, that is, the upper limit, and greater than the radius of the inner circle, that is, the lower limit, in order to ensure effective transmission. Therefore, the end of the light wave vector needs to be in the circular shaded area during the transmission process, and it returns to the origin when and only when it is coupled out. The outer radius is a function of the waveguide material refractive index n, the center wavelength λ ₀ and the maximum angle θ _max .

As an example, the thickness of the substrate 1 of the lens unit may be in the range of 0.3-2.5 mm, the refractive index of the optical material may be 1.4-2.2, and the material may be optical glass or optical resin. The grating may be, for example, a surface relief grating, especially a one-dimensional surface relief grating, and the period may be, for example, 200-600 nm.

Wherein, the one-dimensional surface relief grating may be a positive grating, a blazed grating, a tilted grating or a sinusoidal grating. The depth of the grating groove may be 40-500 nm.

In some embodiments of the present invention, a grating structure is respectively provided in the first diffraction grating area 2 and the second diffraction grating area 3 of the waveguide sheet, and the light is output to the human eye after at least four times of grating modulation in the waveguide sheet. , The two grating structures respectively modulate the light at least twice, for example, the vector superposition of a parallelogram in the light wave k diagram shown in FIG. 5. In the vector superposition diagram shown in Figure 5, the opposite sides of the parallelogram are the same grating structure, so the opposite sides can be guaranteed to be always parallel and equal in size, so that the vector superposition of the four gratings must be zero, which ensures that the input light of the waveguide and The output light is parallel, which improves the image quality of the input human eye. In other words, in the present invention, the light passes through at least four grating modulations of the first diffraction grating area 2 and the second diffraction grating area 3 on the upper and lower surfaces. quality.

FIG. 6 is a schematic diagram of the groove line structure of the grating region 6 according to some embodiments of the present invention. In the schematic diagram of FIG. 6, the vertical direction is taken as the y-axis of the rectangular plane coordinate system, and the horizontal direction is taken as the x-axis of the rectangular plane coordinate system. Here, in the plane of the waveguide sheet, the grating vector of the first diffraction grating region 2 and the grating vector of the second diffraction grating region 3 of the waveguide sheet may be set to be axisymmetric, especially about the vertical direction or the y-axis is the axis. Symmetrical.

In some embodiments, the first diffraction grating region 2 and the second diffraction grating region 3 may have the same grating period T1 and T2, and/or the first diffraction grating region 2 and the second diffraction grating region 3 may have the same grating structure . However, the first grating vector of the first diffraction grating region 2 may be different from the second grating vector of the second diffraction grating region 3.

As shown in FIG. 6, the solid line represents the grating groove line of the first diffraction grating area 2, and the broken line represents the grating groove line of the second diffraction grating area 3. For example, the grating groove lines of two linear diffraction grating regions may form an acute angle θ, especially the included angle θ may be in the range of 40° to 90°, especially 60°. Therefore, assuming that one of the diffraction grating regions is flipped 180° around the x-axis or the y-axis, the grating structure of this flipped diffraction grating region should overlap or at least partially overlap the grating structure of the other diffraction grating region.

By making the grating structures of the diffraction grating area overlap completely symmetrically or at least partially symmetrically about the xy plane, the grating structure can be made in the first diffraction grating area 2 and the second diffraction grating area 3 using the same mold or process, which simplifies the manufacturing process. The grating imprint mold can easily achieve mass production with stable quality while simplifying the process and reducing production costs. At the same time, because the present invention can only set two grating vectors, the degree of freedom in process design is higher, the structure is simple, and stable mass production and processing are easy, thereby having high industrial application value.

It should be pointed out that according to some embodiments of the present invention, the first diffraction grating region 2 provided on the first optical plane of the substrate 1 may be a continuous region, and/or the first diffraction grating region 2 provided on the substrate 1 and the first optical plane The second diffraction grating area 3 on the opposite second optical plane may also be a continuous area. In other words, the diffraction grating area on each optical plane forms a whole area with no interrupted areas.

Here, for example, it is also possible to choose to make the diffraction grating area continuous on the entire optical plane where it is located, that is, to continuously cover the entire optical plane, and the grating areas on the same optical plane all have the same grating vector. For example, the first diffraction grating area 2 has a consistent first grating vector on the entire first optical plane of the substrate 1 and is continuous, that is, continuously covers the entire first optical plane and/or the second diffraction grating area 3 It has a uniform second grating vector on the entire second optical plane of the substrate 1 and is continuous, that is, continuously covers the entire second optical plane.

According to other embodiments of the present invention, the first diffraction grating region 2 provided on the first optical plane of the substrate 1 may also be a discontinuous region, and/or the first diffraction grating region 2 provided on the substrate 1 and the first optical plane The second diffraction grating area 3 on the opposite second optical plane is a discontinuous area. In other words, the diffraction grating area on a specific optical plane can be configured as a plurality of separated grating areas, and there is a base area without a grating structure between these separated grating areas. According to the present invention, the plurality of separated grating regions on the first optical plane all have the same first grating vector, and the plurality of separated grating regions on the second optical plane all have the same second grating vector.

Of course, according to product design requirements and photoelectric performance requirements, the first diffraction grating area 2 on the first optical plane of the substrate 1 and the second diffraction grating area on the second optical plane of the substrate 1 opposite to the first optical plane 3 can be configured to be continuous and/or discontinuous respectively, that is, on the optical planes on both sides of the substrate, the diffraction grating regions can be combined arbitrarily in a continuous or discontinuous structure.

7(a)-(d) are schematic diagrams of grating types according to some embodiments of the present invention. The diffraction grating according to the present invention is an optical element with a periodic structure. The periodic structure can be the peaks and valleys embossed on the surface of the material, that is, the surface relief grating (SRG), or it can be formed by holographic technology exposed inside the material. "Bright and dark interference fringes", namely holographic volume grating (VHG), both eventually cause periodic changes in the refractive index n.

According to some embodiments of the present invention, the specific grating structure may be, for example, a surface relief grating, including but not limited to a positive grating, a blazed grating, a tilted grating, or a sinusoidal grating, as shown in FIGS. 7(a)-(d), respectively. For example, a tilted grating or a triangular blazed grating can maximize the coupling efficiency of light diffracted in the direction of the eye.

It should be pointed out that the diffraction angle corresponding to each diffraction order is determined by the incident angle of the light, the period of the grating and the groove angle of the grating direction, etc., by designing other parameters of the grating, including but not limited to material refractive index n, grating shape, thickness , Duty cycle, etc., can optimize the diffraction efficiency of a certain diffraction order (that is, a certain direction) to the highest, so that most of the light is mainly propagated in this direction after diffraction. Therefore, by appropriately designing the grating structure and the optical path, the technical solution proposed by the present invention can be used to achieve optimal FOV, light efficiency, image clarity, etc. at the same time.

In addition, the groove depth, duty cycle or shape can be modulated on the single-sided coupling-out grating of the waveguide, and the double-sided coupling-out grating of the waveguide can be modulated to make the light coupling intensity uniform in each area. The sex is better.

Through the disclosure given, a lens unit is also provided, including a substrate made of an optical waveguide material, which has a first optical plane and a second optical plane opposite to the first optical plane. The lens unit further includes a first diffraction grating area and a second diffraction grating area, wherein the diffraction grating area provided on the first optical plane of the substrate constitutes the first diffraction grating area, and the first diffraction grating area is provided on the substrate and the first optical plane. The diffraction grating area on the opposite second optical plane constitutes a second diffraction grating area. Here, a coupling and turning area for incident light is provided on the first optical plane of the substrate, wherein the coupling and turning area provided on the first optical plane of the substrate is the same as that provided on the first optical plane of the substrate. The out-coupling area on the first optical plane of the substrate has a uniform grating vector. In some variants, it is also possible to additionally or alternatively provide a coupling and turning area for incident light on the second optical plane of the substrate, wherein the second optical plane provided on the substrate The coupling-in and turning area and the coupling-out area provided on the second optical plane of the substrate have the same grating vector.

In some variants, the part of the diffraction grating area outside the coupling and turning area constitutes a coupling-out area for light coupling out of the lens unit. Thus, the first diffraction grating area on the first optical plane of the substrate is composed of the coupling-in and turning area and the coupling-out area on the first optical plane, and/or the first diffraction grating area on the first optical plane. The second diffraction grating area on the second optical plane opposite to the optical plane is composed of the coupling-in and turning area and the coupling-out area on the second optical plane.

In this way, the lens unit or the substrate 1 of the waveguide sheet can be provided with coupling and turning areas for coupling in and turning image light and out-coupling areas for coupling out image light at will. For the proposed lens unit, The coupling and turning regions can be set in any manner and shape according to the requirements of optical design and structural design, and the remaining parts of the first diffraction grating region 2 and the second diffraction grating region 3 can be used as the coupling and turning regions. Coupling area.

In other words, a fixed coupling and turning area can be provided on the substrate 1 of the lens unit, and the remaining diffraction grating area can be used as the coupling out area. Here, the function of the coupling and turning area is that, on the one hand, the image light can be coupled into the lens unit or waveguide sheet, and on the other hand, the image light can be converted to the desired design after being modulated by the coupling and turning area. The direction of propagation.

FIG. 8 is a structural diagram of the coupling and turning area and the coupling out area of the lens unit according to some embodiments of the present invention. Here, the coupling and turning area a is provided in only one of the optical planes. In the embodiment of FIG. 8, for example, the first diffraction grating area of the lens unit includes coupling and turning areas, as shown by the area a enclosed by solid lines, and the only coupling and turning area a is surrounded by the optical plane. The coupling-out area b is closely connected and completely surrounded by the coupling-out area b. In fact, outside of the coupling and turning area a, the remaining working area of the diffraction grating can be used as a light coupling-out area, which is used to gradually emit image light out of the waveguide into the human eye during the diffraction process. In this embodiment, since the coupling and turning area a is provided only in the first diffraction grating area of the lens unit, the coupling out area may include the part of the first diffraction grating area outside the coupling and turning area a and the opposite side The entire second diffraction grating area.

Since the part of the diffraction grating area outside the coupling and turning area a can be used as the coupling-out area, and the coupling and turning area a is completely surrounded by the coupling-out area b on the optical plane, the diffraction in this embodiment There is no total reflection surface between the coupling-in and turning area and the coupling-out area included in the grating area, which can avoid the phase shift caused by the light beam hitting the boundary between the grating structure and the total reflection surface. Therefore, the light in this embodiment There is no phase mutation during the propagation process, which has the advantage of higher image clarity compared to traditional waveguides.

In the illustrated embodiment, a coupling and turning area for incident light is provided on the first optical plane of the substrate 1, where this coupling and turning area provided on the first optical plane of the substrate 1 is the same as The out-coupling regions on the first optical plane of the substrate 1 have the same or the same grating vector. Additionally or alternatively, it is also possible to provide a coupling and turning area for incident light on the second optical plane of the substrate 1, wherein the coupling and turning area provided on the second optical plane of the substrate 1 and the substrate 1 The out-coupling area on the second optical plane of 1 has a uniform grating vector.

It can be considered that the first and second diffraction regions experienced by the incident light are set as the coupling and turning regions, as shown in the area a in Figure 8, and the coupling-out region part in the same optical plane is shown in Figure 8. Shown in area b in 8 (excluding area a).

In some embodiments, the grating in the coupling and turning area and the coupling-out area in the optical plane can have the same groove depth and duty cycle, so the process can be simplified in the grating manufacturing process, but it can still meet the requirements. Optical performance. In addition, in some variants, the grating groove depth and duty cycle of the coupling and turning area may be greater than the grating groove depth and duty cycle of the coupling-out area located at the periphery thereof, thereby increasing the coupling of the light source. Efficiency and field of view, etc. The variable setting of the grating groove depth and the duty cycle can effectively increase the coupling efficiency of the light source, increase the light energy utilization rate, and expand the coupling field angle. It should be pointed out that the adjustment of the grating groove depth and the duty cycle will not change the grating vector, but will affect the diffraction efficiency. The relationship between the groove depth and the duty cycle of the grating in the coupling and turning area and the coupling-out area in the optical plane described here is also applicable to the following embodiments given in this application.

With the solution proposed by the present invention, any diffraction grating area can be set as the coupling-in and turning area, and the remaining part of the diffraction grating area can be used as the coupling-out area. For example, the grating groove depth of the coupling-in and turning area can be 150-600 nm, and the grating period and grating orientation can be consistent with the coupling-out area in the optical plane.

9 is a structural diagram of the coupling-in and turning-in area and the coupling-out area of the lens unit according to some embodiments of the present invention, where a coupling and turning area are respectively provided in the first and second diffraction grating regions of the lens unit . In this embodiment, since the part of the diffraction grating region 6 other than the coupling and turning regions can be used as the coupling-out regions, the coupling and turning regions on both sides of the waveguide sheet are respectively completely covered by the corresponding coupling-out regions b. Surrounded. The main difference compared with the embodiment of FIG. 8 is that an additional coupling and turning area for incident light is provided on the second optical plane of the substrate 1, where this coupling is provided on the second optical plane of the substrate 1. And the turning area and the out-coupling area on the second optical plane of the substrate 1 have the same grating vector.

The coupling and turning regions may exist in the first and second diffraction grating regions at the same time. The coupling and turning areas of the two surfaces have overlapping intersections, that is, in the plane where the lens unit is located, the coupling and turning areas set on the first optical plane of the substrate 1 and the second optical plane set on the substrate 1 The coupling and turning areas on the optical plane have at least partially overlapping areas, as shown in FIG. 9. In Figure 9, the shaded area c represents the overlap area, area d represents the remaining area after removing the overlap area from the coupling and turning area of the first optical plane, and area e represents the coupling and turning area of the second optical plane after removing the overlap area. The remaining area.

Here, for example, the superimposed area c may be used as the coupling area of the incident light, and the areas d and e may be used as the turning area of the light. That is to say, the coupling and turning area includes the coupling area c and the turning areas d and e. Wherein, the coupling area c can be a circle as shown in the figure, or can be a triangle, a rectangle, an ellipse, or the like. The turning regions d and e may have the shape shown in the figure or any polygonal shape. In some variants, the coupling and turning area contours of the waveguide sheet on the two sides may have a mirror symmetry relationship, that is, when the waveguide sheet is flipped up and down by 180° around the x-axis or y-axis, the gratings on the two sides The structure of the area 6 is completely overlapped, thereby saving the manufacturing mold and facilitating the preparation and processing. Of course, according to the design and performance requirements, the contours and/or positions of the coupling and turning regions of the waveguide sheet on the two surfaces can be completely consistent.

In this embodiment, since the part of the diffraction grating area outside the coupling and turning area can be used as the coupling-out area, and the coupling and turning area is completely surrounded by the coupling-out area in the optical plane, the diffraction grating area There is no total reflection surface between the included coupling and turning area and the coupling out area, which can avoid the phase shift caused by the light beam hitting the boundary between the grating structure and the total reflection surface, so the light in this embodiment is propagating There is no phase mutation in the process, which has the advantage of higher image clarity compared to traditional waveguides.

FIG. 10 is a structural diagram of the coupling and turning area and the coupling out area of the lens unit according to some embodiments of the present invention. Here, the coupling and turning area are respectively connected to the corresponding coupling out area. In this embodiment, as shown in the figure, the coupling and turning areas on both sides of the waveguide sheet are only partially connected to the corresponding coupling-out area b in the optical plane, instead of being completely surrounded by the coupling-out area b.

Fig. 11 is a structural diagram of the coupling and turning area and the coupling out area of the lens unit according to some embodiments of the present invention. The coupling out areas are not connected. In this embodiment, since the coupling-in and turning area is completely separated from the corresponding coupling-out area, the entire diffraction grating area on both sides of the waveguide sheet can be used as the coupling-out area b. In this case, the first diffraction grating area provided on the first optical plane of the substrate and the second diffraction grating area provided on the second optical plane of the substrate opposite to the first optical plane are both configured as Discontinuous or discontinuous, and are divided into coupling-in and transition areas and coupling-out areas respectively.

As shown in Fig. 11, the coupling and turning areas are not directly connected or adjacent to the coupling-out areas of the optical plane, but are separated from each other. Although the grating structure in the coupling and turning area and the grating structure in the coupling-out area in the optical plane form separate areas, all grating structures on the same optical plane still have the same or the same grating vector.

According to some embodiments of the present invention, if the uniformity of the out-coupling pupil is not high, the out-coupling area b can be set as a uniform grating, that is, for example, having a uniform groove depth and duty cycle. If there is a higher uniformity requirement for the coupling-out pupil, the coupling-out area can be set as a variable grating, that is, for example, the farther the coupling-out area b is from the coupling-in area c, the greater the grating groove depth and the duty cycle. Further, the groove depth, duty cycle, or tooth shape modulation can be performed on the single-sided coupling-out grating, or both coupling-out grating surfaces can be modulated, so that the light coupling-out intensity uniformity in each area is better.

On the basis of the embodiments shown in FIGS. 8 to 11, for example, one or more coupling and turning regions may be provided on each optical plane. Here, the coupling and turning regions on both sides of the waveguide can also be selected. The turning area is mirror-symmetrical or arranged axisymmetrically in the plane where the waveguide sheet is located. In some modifications, one or more, especially two coupling and turning regions may also be arranged on one optical plane, while the other optical plane is not provided with the coupling and turning regions.

According to the present invention, the relative positional relationship between the coupling and turning area and the coupling-out area on the optical plane can also adopt different variants. For example, the coupling and turning area can be completely located in the coupling-out area, and partly connected with the coupling-out area. Or completely separate from the decoupling area. In other words, since the part of the diffraction grating region other than the coupling and turning regions can be used as the coupling-out region, the coupling and turning regions c, d, and e can be contained in, semi-contained, or separated from the The grating is coupled out of the area b.

According to the present invention, when viewed in a direction perpendicular to the plane of the waveguide sheet, the coupling and turning area provided on the first optical plane of the substrate 1 and the coupling and turning area provided on the second optical plane of the substrate 1 preferably have Correspond to the overlapped part of the area. That is to say, although the coupling and turning regions are on both sides of the waveguide sheet, the projections of these coupling and turning regions on the plane of the waveguide sheet may have overlapping regions.

In addition, the first diffraction grating area 2 provided on the first optical plane of the substrate 1 may be constituted as a continuous area, and/or the second diffraction grating provided on the second optical plane of the substrate 1 opposite to the first optical plane The area 3 may also be configured as a continuous area. In this case, the corresponding coupling-in and turning area can be completely or half-contained in the corresponding coupling-out area, that is, become a part of the overall grating structure.

It should also be pointed out that the first diffraction grating region 2 provided on the first optical plane of the substrate 1 and the second diffraction grating region 3 provided on the second optical plane of the substrate 1 opposite to the first optical plane may have the same or Different structures and shapes, the coupling and turning areas and the coupling out areas also provided on both sides of the substrate 1 can also have the same or different structures and shapes, and the specific setting methods, structures, shapes, and optical parameters can be According to specific design and performance needs, adjustments are made and different combinations are used, which are all within the scope of the disclosure of the present invention.

The technical solution proposed by the present invention can significantly simplify the design and processing difficulty of the lens unit and the AR device, so that the structure of the waveguide sheet can flexibly and reliably match the optical performance requirements and the mechanical structure requirements, and meet the dual requirements of product performance and manufacturing costs. .

The lens unit proposed by the present invention can be flexibly applied to various augmented reality devices (AR devices), such as AR glasses, head-up displays, and other wearable electronic devices.

According to the present invention, an AR device, especially AR glasses, is also proposed, which includes, for example, a frame for installing a lens unit, a temple for wearing AR glasses, a left lens unit and a right lens unit installed in the frame, and A computing unit for data processing and image signal generation and a micro projector, wherein the micro projector outputs an image according to the image signal generated by the computing unit.

With the technical solution proposed by the present invention, it is possible to arbitrarily set the coupling and turning area on the optical plane of the base of the lens unit. In the following, taking AR glasses as an example, the AR device using the lens unit will be exemplarily described in detail.

FIG. 12 is a schematic diagram of AR glasses according to some embodiments of the present invention, where the AR device is AR glasses.

As shown in the figure, the AR glasses include a frame 60 for installing a lens unit, a temple 90 for wearing AR glasses, and a left lens unit 10 and a right lens unit 20 installed in the frame 60. Here, the temple 90 may be connected to the spectacle frame 60 in any manner, for example, in a flexible manner, or in the form of a hinge, thereby forming the main body of the AR glasses. The electronic components and optical components of the AR glasses can be selectively mounted on the temple 90 and/or the frame 60, or embedded/buried in its material. The electronic components and optical components include, but are not limited to, a computing unit 50 for data processing and generating image signals, a camera 30, a micro-projector 40 that outputs images according to the image signal generated by the computing unit 50, a microdisplay, and a space Sensors and position sensors, etc.

The lens unit (optical waveguide sheet) is a display component in the AR device. In the embodiment shown in FIG. 12, the AR glasses include a left lens unit 10 (left-eye optical waveguide display system) and a right lens unit 20 (right-eye optical waveguide display system), and the camera 30 can be provided in the left lens unit 10 and the right lens unit. The middle position between the units 20 is roughly the middle position above the bridge of the nose. The micro projector 40 and the calculation unit 50 are provided in the temple 90, for example.

It should be pointed out that the optical components and electronic components included in the AR glasses can be flexibly selected according to design requirements and arranged arbitrarily according to structural conditions, and are not limited to the forms given in the examples. For example, the left lens unit 10 and the right lens unit 20 can be constructed as two separate lens units, or can be two components of an integral lens unit. In the example of FIG. 12, the camera 30 is placed in the middle position between the left lens unit 10 and the right lens unit 20, but other suitable optical components and electronic components can also be considered at this position. In the following embodiments There is a detailed description in this.

During operation, the microdisplay in the microprojector 40 displays an image, which is input to the coupling and turning area of the optical waveguide lens through the projection lens, and then enters the human eye through a series of light transmission. The computing unit 50 can not only provide image signals for the micro display, but can also communicate with other components in the system, such as the camera 30, the space sensor, the position sensor, the micro projector 40, and the like.

Here, microdisplays that can be used include, but are not limited to, digital light processors (DLP), liquid crystal on silicon (LCoS), organic light emitting diodes (OLED), and micro light emitting diodes (Micro LED). The optical waveguide lens has a high transmittance, allowing users to clearly observe the real world.

The camera 30 and the spatial sensor may be an RGB camera, a monochrome camera, an eye tracking sensor, and a depth camera, or a combination thereof. The RGB or monochrome camera can obtain the environment picture in the real scene, the eye tracking sensor can realize the function of eye tracking, the depth camera can obtain the depth information of the scene, and realize the functions of face and gesture recognition.

The position sensor can be a combination of accelerometer, gyroscope, magnetometer and GPS receiver. After the computing unit 50 processes the signal from the position sensor, the virtual image can be superimposed on the real environment more accurately.

FIG. 13 is a schematic diagram of AR glasses according to some embodiments of the present invention, with a modified shape of the glasses. As shown in FIG. 13, the AR glasses include a frame 60 for installing a lens unit, a temple 90 for wearing AR glasses, and a left lens unit 10 and a right lens unit 20 installed in the frame 60. Here, as an example, the left lens unit 10 and the right lens unit 20 are configured as two separate lens units, which are installed in the lens frame 60 respectively.

The difference from the embodiment shown in FIG. 12 is that in the embodiment shown in FIG. 13, the lens unit installed in the lens frame 60 adopts a corner cutting process. That is, for example, on the basis of a rectangular basic shape, the lens unit has a chamfered shape at at least one right angle thereof. Correspondingly, the frame 60 of the AR glasses may also adopt a cut corner shape that matches the cut corner shape of the lens unit. For example, the waveguide sheet is structured as a square with missing corners, thereby matching the shape of the turning area of the waveguide sheet, not only can reduce the volume of AR glasses, but also can match the structural space requirements of different components, and can adopt more flexible Product design styling. Of course, the waveguide sheet can also be constructed in other arbitrary shapes with missing or cut corners, such as rectangles and polygons.

In some modified solutions, the lens frame 60 may not be provided with a chamfered shape, but the lens frame 60 may leave a place for the installation of components at a position corresponding to the chamfered shape of the lens unit, thereby Electronic components or other devices can be arranged at the corners of the lens unit of the frame.

FIG. 14 is a schematic diagram of AR glasses according to some embodiments of the present invention. As shown in FIG. 14, the overall structure of the AR glasses is similar to the previous embodiment. The AR glasses include a frame 60 for mounting the lens unit, a temple 90 for wearing the AR glasses, and a left lens unit 10 mounted in the frame 60. And the right lens unit 20. In this embodiment, the left lens unit 10 and the right lens unit 20 installed in the lens frame 60 are constructed as an integral lens unit. In other words, the left lens unit 10 and the right lens unit 20 are formed by different components of a single lens unit, respectively. Therefore, the base 1 made of the optical waveguide material of the left lens unit 10 and the right lens unit 20 is continuous and integrated.

To this end, a separate light guide element 70 may be provided, which guides the image light of the micro projector 40 or micro display to the coupling and turning area 35 of the lens unit. With the provided light guide element 70, the left lens unit 10 and the right lens unit 20 can share a single micro projector 40 or micro display. Alternatively, the coupling and turning area 35 may be arranged at the geometric center of the waveguide sheet, for example, on the axis of symmetry. One end of the light guide element 70 is connected to the micro projector 40, and the other end is connected to the coupling and turning area 35 of the lens unit, so as to transmit the image light from the micro projector 40 or the micro display to the lens unit.

In the illustrated embodiment, the coupling and turning area 35 is arranged in the middle position between the left lens unit 10 and the right lens unit 20, that is, approximately in the middle position above the bridge of the nose, so that the left lens unit can be easily realized. 10 and the right lens unit 20 uniform and coordinated image transmission effect. At the same time, by using a suitably shaped light guide element 70, for example in the form of an optical fiber, components such as the computing unit 50, microprojector 40 or microdisplay of the display system can be arranged at the appropriate position of the AR device, so as to make rational use of the structural space on the one hand. , Flexible design, on the other hand to ensure image transmission and display quality. In the embodiment of FIG. 14, the micro-projector 40 and the computing unit 50 are arranged on one of the temples 90, and the image light is transmitted from the micro-projector 40 through the light guide element 70 to the coupling and turning area 35 of the lens unit through The coupling and turning area 35 enters the lens unit, and is finally shot into the human eye through the coupling-out area by means of total reflection and diffraction propagation.

FIG. 15 is a schematic diagram of AR glasses according to other embodiments of the present invention. In this embodiment, the possibility of arranging optical components and electronic components in different ways is given as an example. In the embodiment shown in Figs. 12-11, the camera 30 is arranged in the middle position between the left lens unit 10 and the right lens unit 20, that is, approximately in the middle position above the bridge of the nose. In contrast, in the embodiment of FIG. 15, instead of the camera 30, the micro projector 40 or micro display can be directly arranged in the middle position between the left lens unit 10 and the right lens unit 20, that is, roughly above the bridge of the nose. In the middle of the house. Therefore, the image light emitted by the micro projector 40 or the micro display can directly enter the lens unit through the coupling and turning area, and the additional light guide element 70 in the middle is omitted.

Similarly, in combination with the specific shape and space structure of the AR device, it is also possible to consider changing the placement and manner of other optical components and electronic components. For example, in the example of FIG. 15, the sensor 80, including a position sensor and/or a space sensor, etc., may be arranged in one or both of the temples 90. Obviously, under the premise of meeting the structure and working requirements of the optical components and electronic components of the AR device, the shape of the structural lens unit can be changed, and the positions of different components can be flexibly set.

It should be pointed out that the technical solution proposed here is not limited to the content in the above description, and those skilled in the art can make many variations and modifications to the above embodiment without departing from the inventive idea of the present invention, and these variations And modifications belong to the protection scope of the present invention.

Claims (22)

1. A lens unit, characterized in that it comprises:

   A substrate composed of an optical waveguide material, which has a first optical plane and a second optical plane opposite to the first optical plane; and

   The first diffraction grating area and the second diffraction grating area, where the diffraction grating area provided on the first optical plane of the substrate constitutes the first diffraction grating area, and the second diffraction grating area is provided on the substrate opposite to the first optical plane. The diffraction grating area on the optical plane constitutes the second diffraction grating area;

   Wherein, the first diffraction grating area has a consistent first grating vector on the first optical plane of the substrate, and the second diffraction grating area has a consistent first grating vector on the second optical plane of the substrate opposite to the first optical plane. The second raster vector.
2. The lens unit according to claim 1, wherein the first diffraction grating area provided on the first optical plane of the substrate is a continuous area, and/or the first diffraction grating area provided on the substrate opposite to the first optical plane The second diffraction grating area on the two optical planes is a continuous area.
3. The lens unit according to claim 2, wherein the first diffraction grating area is continuous on the entire first optical plane of the substrate, and/or the second diffraction grating area is continuous on the entire second optical plane of the substrate .
4. The lens unit according to claim 1, wherein the first diffraction grating area provided on the first optical plane of the substrate is a discontinuous area, and/or the first diffraction grating area provided on the substrate opposite to the first optical plane The second diffraction grating area on the two optical planes is a discontinuous area.
5. The lens unit according to any one of claims 1 to 4, wherein the first grating vector of the first diffraction grating region is different from the second grating vector of the second diffraction grating region.
6. 5. The lens unit according to any one of claims 1 to 5, wherein the incident light is coupled out after at least four grating modulations in the lens unit.
7. The lens unit according to any one of claims 1 to 6, wherein a first diffraction grating area provided on a first optical plane of the substrate and a first diffraction grating area provided on the substrate opposite to the first optical plane The second diffraction grating regions on the two optical planes respectively modulate the incident light at least twice.
8. The lens unit according to any one of claims 1 to 7, wherein a first diffraction grating area provided on a first optical plane of the substrate and a first diffraction grating area provided on the substrate opposite to the first optical plane The second diffraction grating regions on the two optical planes have the same grating period.
9. The lens unit according to any one of claims 1 to 8, wherein, in the plane where the lens unit is located, the grating groove lines of the first diffraction grating area and the grating groove lines of the second diffraction grating area have an angle of 40-90°的角。 The included angle.
10. 9. The lens unit according to claim 9, wherein the grating groove line of the first diffraction grating area and the grating groove line of the second diffraction grating area have an included angle of 60°.
11. The lens unit according to any one of claims 1 to 10, wherein, during the diffraction propagation process of the lens unit, the diffraction angle of the diffracted light satisfies the formula:

    

    Where |k _r | represents the amplitude of the target light wave vector, n is the refractive index of the optical waveguide material, λ ₀ is the center wavelength of the image light source, and θ _max is the maximum transmission angle.
12. The lens unit according to any one of claims 1 to 11, wherein the optical waveguide material constituting the substrate is optical glass or optical resin.
13. The lens unit according to any one of claims 1 to 12, wherein a first diffraction grating area provided on a first optical plane of the substrate and a first diffraction grating area provided on the substrate opposite to the first optical plane The second diffraction grating area on the two optical planes includes a surface relief grating.
14. The lens unit according to claim 13, wherein a first diffraction grating area provided on a first optical plane of the substrate and a first diffraction grating area provided on a second optical plane of the substrate opposite to the first optical plane The two diffraction grating regions include positive gratings, blazed gratings, tilted gratings and/or sinusoidal gratings.
15. The lens unit according to any one of claims 1 to 14, wherein a first diffraction grating area provided on a first optical plane of the substrate and a first diffraction grating area provided on the substrate opposite to the first optical plane The second diffraction grating regions on the two optical planes at least partially overlap each other on both sides of the substrate.
16. The lens unit according to any one of claims 1 to 15, wherein, in the plane where the lens unit is located, the grating vector of the first diffraction grating region and the grating vector of the second diffraction grating region are axisymmetric.
17. The lens unit according to any one of claims 1 to 15, wherein a first diffraction grating area provided on a first optical plane of the substrate and a first diffraction grating area provided on the substrate opposite to the first optical plane The second diffraction grating regions on the two optical planes have the same slot line structure.
18. The lens unit according to claim 16, wherein a first diffraction grating area provided on a first optical plane of the substrate and a first diffraction grating area provided on a second optical plane of the substrate opposite to the first optical plane The two diffraction grating regions have the same slot line structure.
19. The lens unit according to any one of claims 1 to 18, wherein the lens unit is a see-through light guide lens unit.
20. The lens unit according to any one of claims 1 to 19, wherein a coupling and turning area for incident light is provided on the first optical plane and/or the second optical plane of the substrate.
21. An AR device comprising at least one lens unit according to any one of claims 1 to 20.
22. The AR device according to claim 21, wherein the AR device is AR glasses.

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