WO2021134674A1

WO2021134674A1 - Near-eye display device

Info

Publication number: WO2021134674A1
Application number: PCT/CN2019/130911
Authority: WO
Inventors: 杨濛; 陈晓杰
Original assignee: 诚瑞光学(常州)股份有限公司
Priority date: 2019-12-31
Filing date: 2019-12-31
Publication date: 2021-07-08

Abstract

Disclosed is a near-eye display device. The near-eye display device comprises a waveguide (10), and an in-coupling grating (20), a deflection grating (30) and an out-coupling grating (40), which are separately arranged on the waveguide (10). The waveguide (10) comprises an upper surface (11) and a lower surface (12), which are oppositely arranged, the in-coupling grating (20) comprises a first in-coupling grating body (21) arranged on the upper surface (11) and a second in-coupling grating body (22) arranged on the lower surface (12), the first in-coupling grating body (21) and the second in-coupling grating body (22) are opposite each other and grating vectors thereof are perpendicular to each other, and the sum of the grating vectors of the in-coupling grating (20), the deflection grating (30) and the out-coupling grating (40) is equal to zero. Transmission and exit pupil expansion of three primary colors, i.e. RGB, can be achieved by means of a single waveguide, such that field of view missing of any color cannot be caused, and manufacturing difficulty is reduced.

Description

Near-eye display device

【Technical Field】

The present invention relates to the technical field of display devices, and in particular to a near-eye display device.

【Background technique】

Augmented Reality (AR) technology, also known as mixed reality technology, can superimpose virtual information into the real world, and can be applied to many fields such as education, assisted driving, shopping, and medical care. AR technology has brought a new way of interaction, which may replace or partially replace mobile phones as a personal computing platform in the future.

Diffractive waveguide type near-eye display devices use gratings to achieve exit pupil expansion. Due to the strong dispersion characteristics of gratings, the display color RGB (R stands for Red (red), G stands for Green (green), B stands for Blue (blue) )) It is necessary to prepare a separate waveguide for each of the three primary colors in the image, thereby increasing the difficulty of preparing the near-eye display device. Therefore, how to design a near-eye display device with low preparation difficulty is an urgent problem to be solved.

[Summary of the invention]

The purpose of the present invention is to provide a near-eye display device to solve the problem of preparing a separate waveguide for each of the three primary colors when displaying colorful RGB images, thereby increasing the difficulty of preparing the near-eye display device.

The technical solution of the present invention is as follows: the object of the present invention is to provide a near-eye display device, comprising a waveguide and a coupling grating, a deflection grating and a coupling-out grating arranged on the waveguide, the waveguide comprising oppositely arranged upper surfaces And the lower surface, the coupling grating includes a first coupling grating disposed on the upper surface and a second coupling grating disposed on the lower surface, the first coupling grating and the second coupling grating The gratings are directly opposite and the grating vectors are perpendicular to each other, the deflection grating includes a first deflection grating corresponding to the first coupling grating, and a second deflection grating corresponding to the second coupling grating, The orthographic projections of the deflection grating, the coupling-in grating, and the coupling-out grating on the waveguide do not overlap and are spaced apart from each other, and the first coupling-in grating and the first deflection grating are separated from each other. The minimum distance is less than the minimum distance between the first coupling-in grating and the coupling-out grating, and the minimum distance between the second coupling-in grating and the second deflection grating is less than the second coupling-in grating The minimum distance from the coupling-out grating;

The coupling-out grating is disposed on the upper surface or the lower surface, and includes coupling-out portions arranged in an array, and the coupling-out portion has a first out-coupling grating vector and a second out-coupling grating vector perpendicular to each other, so The sum of the grating vector of the first coupling-in grating, the grating vector of the first deflection grating, and the grating vector of the first coupling-out grating is equal to zero, and the grating vector of the second coupling-in grating and the second deflection grating are equal to zero. The sum of the grating vector of the grating and the grating vector of the second out-coupling grating is zero.

As an improvement, the first coupled-in grating and the second coupled-in grating have the same area and are arranged at intervals.

As an improvement, the first coupling grating and the first deflection grating are both arranged on the upper surface.

As an improvement, the second deflection grating is located on the upper surface.

As an improvement, at least one of the coupling-in grating, the coupling-out grating, and the deflection grating is etched and formed on the waveguide.

As an improvement, at least one of the coupling-in grating, the coupling-out grating, and the deflection grating is attached to the waveguide.

As an improvement, the upper surface of the waveguide is close to the image source, the first coupling grating is a transmission grating, and the second coupling grating is a reflection grating.

As an improvement, the first coupling grating has a square shape, and the orthographic projections of the first deflection grating and the second deflection grating on the upper surface are respectively located adjacent to the first coupling grating. On both sides.

As an improvement, the first coupled-in grating includes a first side and a second side that are perpendicular to each other, the first deflection grating is trapezoidal and is directly opposite to the first side and arranged at intervals. The second deflection grating is directly opposite to the second side and is arranged at intervals.

As an improvement, the first deflection grating and the second deflection grating are trapezoidal or square, and a side close to the coupling grating is parallel to the coupling grating.

As an improvement, the area of the deflection grating is larger than the area of the coupling-in grating and smaller than the area of the coupling-out grating.

As an improvement, the angle between the grating vector coupled into the grating and the grating vector corresponding to the coupled out grating is 45°.

As an improvement, both the first coupling grating and the second coupling grating have polarization selectivity, the near-eye display device further includes a polarization modulator disposed between the first coupling grating and the image source, and The light beam of the image source is modulated by the polarization modulator to output the polarization states of the first coupling grating and the second coupling grating respectively corresponding to output values.

As an improvement, the coupling-out portions are arranged in a two-dimensional periodic arrangement, and the coupling-out portions are recessed and formed from the surface of the waveguide or protruding from the surface of the waveguide to form protrusions.

As an improvement, the coupling part is a columnar or spherical protrusion; or, the coupling part is a spherical groove or a cylindrical groove.

As an improvement, the waveguide is a single-layer waveguide.

The beneficial effects of the present invention are:

The near-eye display device includes a waveguide, a coupling grating, a deflection grating, and a coupling-out grating. The coupling-in grating, the deflection grating, and the coupling-out grating are respectively arranged on the waveguide. The grating vector sum of the coupling-in grating, the deflection grating and the coupling-out grating Equal to zero, the transmission of the three primary colors of RGB and the expansion of the exit pupil can be realized through the waveguide, which will not cause any loss of the field of view of any color, which reduces the difficulty of manufacturing.

【Explanation of the drawings】

FIG. 1 is a perspective view of a near-eye display device provided by an embodiment of the present invention;

Fig. 2 is a schematic cross-sectional view taken along the A-A direction of Fig. 1;

FIG. 3 is an enlarged schematic diagram of the coupled grating in area B of FIG. 2;

4 is a schematic diagram of the wave vector space in the waveguide of the near-eye display device according to an embodiment of the present invention;

Fig. 5 is a schematic diagram of a specific structure of the coupling-out grating in Fig. 1;

FIG. 6 is a light propagation path diagram of a near-eye display device provided by an embodiment of the present invention.

In the figure: 10, waveguide; 11, upper surface; 12, lower surface; 20, coupling grating; 21, first coupling grating; 211, first side; 212, second side; 22, second coupling Input grating; 30, deflection grating; 31, first deflection grating; 32, second deflection grating; 40, coupling out grating.

【Detailed ways】

The present invention will be further described below in conjunction with the drawings and embodiments.

Referring to FIG. 1, an embodiment of the present invention provides a near-eye display device, including a waveguide 10 and a coupling grating 20, a deflection grating 30, and a coupling-out grating 40 disposed on the waveguide 10, the deflection grating The orthographic projections of the grating 30, the coupling-in grating 20, and the coupling-out grating 40 on the waveguide 10 do not overlap and are spaced apart from each other. The area of the coupling grating 20 and the deflection grating 30 is larger than that of the coupling grating. The area of the entrance grating 20 is smaller than the area of the outcoupling grating 40. Specifically, the waveguide 10 is a single-layer waveguide; the coupling in grating 20, the outcoupling grating 40, and the deflection grating 30 At least one etching is formed on the waveguide 10; in addition, it should be noted that at least one of the coupling-in grating 20, the coupling-out grating 40, and the deflection grating 30 is attached to the waveguide 10 The coupling grating 20 is used to couple the received light into the waveguide 10; the deflection grating 30 is used to change the direction of the light coupled into the waveguide 10 by the coupling grating 20 and transmit it to the coupling out Grating 40; In one embodiment, the angle between the grating vector of the coupling-in grating 20 and the grating vector corresponding to the coupling-out grating 40 is 45°.

Please refer to FIGS. 2 to 3 together. In one embodiment, the waveguide 10 includes an upper surface 11 and a lower surface 12 opposed to each other, and the coupling grating 20 includes a first coupling disposed on the upper surface 11. Into the grating 21 and the second in-coupling grating 22 arranged on the lower surface 12, the first in-coupling grating 21 and the second in-coupling grating 22 are directly opposite and the grating vectors are perpendicular to each other; preferably, the first coupling The entrance grating 21 and the second coupling grating 22 have the same area and are spaced apart from each other; in one embodiment, the first coupling grating 21 has a square shape. In other embodiments of the present invention, the coupling grating may also be It is a circle or other shapes; specifically, the first coupling grating 21 and the second coupling grating 22 each include a first side 221 and a second side 222 perpendicular to each other.

The deflection grating 30 includes a first deflection grating 31 corresponding to the first coupling grating 21, and a second deflection grating 32 corresponding to the second coupling grating 22. The first The minimum distance between the coupling-in grating 21 and the first deflection grating 31 (please refer to h1 in FIG. 1) is smaller than the minimum distance between the first coupling-in grating 21 and the coupling-out grating 40 (please refer to 1), the minimum distance between the second coupling-in grating 22 and the second deflection grating 32 is smaller than the minimum distance between the second coupling-in grating 22 and the coupling-out grating 40 distance.

In an embodiment, the first deflection grating 31 has a trapezoidal shape and is directly opposite to the first side 221 and arranged at intervals, and the second deflection grating 32 is connected to the first coupling grating 21. The second side edges 222 are directly opposite and arranged at intervals; in one embodiment, the first coupling grating 21 is a transmissive grating, and the second coupling grating 22 is a reflective grating.

In an embodiment, the first deflection grating 31 is also disposed on the upper surface, and the orthographic projections of the first deflection grating 31 and the second deflection grating 32 on the upper surface 11 are respectively located The first coupling-in grating 21 is adjacent to two sides; more specifically, the first deflection grating 31 and the second deflection grating 32 are trapezoidal or square, and the first deflection grating The sides of the second deflection grating 31 and the second deflection grating 32 close to the coupling grating 20 are both parallel to the coupling grating 20.

The coupling-out grating 40 is disposed on the upper surface 11 or the lower surface 12, and includes coupling-out portions 41 arranged in an array. The coupling-out portion 41 has a first coupling-out grating vector and a second coupling that are perpendicular to each other. The vector sum of the grating vector of the first coupling-in grating 21, the grating vector of the first deflection grating 31, and the vector of the first coupling-out grating is equal to zero, and the second coupling-in grating 22 The vector sum of the grating vector of, the grating vector of the second deflection grating 32 and the second out-coupling grating vector is zero.

Referring to FIG. 5, specifically, the coupling portions 41 are arranged in a two-dimensional periodic arrangement, and the coupling portions 41 are recessed and formed from the surface of the waveguide 10 or protrude from the surface of the waveguide 10 to form protrusions. More specifically, the coupling portion 41 is a columnar or spherical protrusion; or, the coupling portion 41 is a spherical groove or a cylindrical groove.

In one embodiment, the upper surface 11 of the waveguide 10 is close to the image source, the first coupling grating 21 and the second coupling grating 22 have a limited wavelength bandwidth, and the first coupling grating 21 can diffract blue to green light. The second in-coupling grating 22 can diffract the incident light in the green to red wavelength range. In another embodiment, both the first coupling grating 21 and the second coupling grating 22 have polarization selectivity, and the near-eye display device further includes a polarization disposed between the first coupling grating 21 and the image source. Modulator, the light beam of the image source is modulated by the polarization modulator to output the first polarized light corresponding to the first in-coupling grating 21 and the second polarized light corresponding to the second in-coupling grating 22, so The first polarized light has a first polarization state, and the second polarized light has a second polarization state; the first coupling grating 21 can only diffract the first polarized light, and then it is coupled into the waveguide 10 before being transmitted to the first polarized light. The deflection grating 31, the first deflection grating 31 is transmitted to the out-coupling grating 40; the second in-coupling grating 22 can only diffract the second polarized light, and then it is coupled into the waveguide 10 and then transmitted to the second deflection grating 32 , The second deflection grating 32 is then transmitted to the coupling-out grating 40.

Please refer to Figure 1 again. The grating has a strong dispersive effect on the light, which will reduce the quality of the display. In order to ensure that the light passing through the entire waveguide display device will not be dispersive, it is necessary to satisfy that the sum of the three grating vectors is equal to zero, that is, K ₁ + K ₂ +K ₃ =0.

As shown in Figure 4, Figure 4 is the wave vector space of the light inside the waveguide 10. Figure 4 includes Figure 4-1 and Figure 4-2. In the wave vector space of Figure 4-1, the coupling grating 21 couples the blue light and Green light, but only blue light and green light on the left half of the field of view can be transmitted in the waveguide 10. In the wave vector space of Fig. 4-2, the coupling grating 22 couples red and green light, but only the red light and the right half The green light field can be transmitted in the waveguide 10; in Figure 4, the refractive index of air is n ₀ , the refractive index of the waveguide 10 is n ₁ , and the inner dashed circle represents the total internal reflection (TIR) of the waveguide 10 The boundary, where the wave vector of the light is larger than this boundary, can cause total internal reflection (TIR) in the waveguide 10; the TIR conditions are:

Therefore, the radius of the inner dashed circle is n ₀ ; the rectangular frame represents the distribution range of the light beam displaying the image in the wave vector space. In this embodiment, the light beam includes the light beam of the image source and is output after being modulated by the polarization modulator. The first polarized light and the second polarized light displayed alternately at a preset frequency; k ₀ is the wave vector of the incident light in free space, k _x is the component of the wave vector of the incident light on the x axis, and k _y is the incident light The component of the wave vector on the y-axis; the outer dashed circle is the boundary of the exit pupil continuity, and its radius is approximately equal to n ₁ ; so the wave vector of the light can only propagate in the waveguide 10 when it falls between these two circles; the solid line and The dashed arrows respectively indicate the grating vectors corresponding to the in-coupling grating 20, the deflection grating 30 and the out-coupling grating 40 of different colors of light; in order to achieve color display, RGB (R stands for Red, G stands for Green, B stands for The light of the three primary colors of Blue (blue) needs to be coupled into the waveguide 10 at the same time. At this time, the light of any wavelength is satisfied: the light of the output waveguide and the light of the input waveguide are in the same direction, so the light enters the waveguide 10 and does not exit the waveguide. Dispersion will occur; in addition, it should be pointed out that the RGB fields of view are completely coincident before coupling. In Figure 4 for more intuitive, the three fields of view are staggered by a small distance; the grating vector of the first coupled grating 21 The direction is the positive half-axis direction of the x-axis, and the grating vector is just large enough to couple all blue light into the waveguide 10, as shown in Figure 4-1. According to the grating vector

_{The period Λ 1 of the} grating vector of the first coupled grating 21 is calculated. For different wavelengths, normalized grating vector

Related to the wavelength, the longer the wavelength, the larger the normalized grating vector. Therefore, the normalized grating vector of the green light in Figure 4-1 is larger than that of the blue light, and the left half of the green light (that is, the _{direction of the negative half axis close to the K x} /K ₀ axis) can be coupled into the waveguide 10, the same as the blue light The field of view is transmitted to the first deflection grating 31 through total reflection in the waveguide 10; the deflection grating 30 can change the transmission direction of light and deflect the light into the coupling-out grating 40; the second coupling-in grating 22 The grating vector direction of is the negative half-axis direction of the y-axis, and the size of the grating vector of the second coupled grating 22 is just enough to couple the red light into the waveguide 10, as shown in Figure 4-2; according to the size of the _{grating vector K 2} _{The period Λ 2} of the grating vector can be calculated; at the same time, the entire field of view of green light can also be coupled into the waveguide 10, but after being diffracted by the deflection grating 30, the left half of the field of view of the green light will leak out of the waveguide 10, leaving only The right half of the field of view; while the red light can retain the entire field of view; in order to allow all the red light and part of the green light to pass through the first coupling grating 21 to the second coupling grating 22; it can be on the surface of the near-eye display device A polarization modulator is added to convert the light received by the near-eye display device into S or P polarized light. At the same time, the first coupling grating 21 and the second coupling grating 22 can be designed to have polarization selectivity, for example, the first The coupled-in grating 21 can only diffract light with the polarization state of S, while the second coupled grating 22 can only diffract light with the polarization state of P; using the idea of time division multiplexing, the microdisplay alternately displays blue, green and For red and green images, the polarization modulator correspondingly changes the light into S and P polarizations alternately; in this way, blue and green light can be coupled into the waveguide 10 by the first coupling grating 21, and red and green light can be coupled into the second grating 22 Coupling into the waveguide 10; the blue and the left half of the green field of view, red and right half of the green field of view will eventually be coupled out of the grating 40 and out of the waveguide 10 to reach the human eye; images of different colors and fields of view are coupling out of the grating 40 Here is fused; please refer to Figure 6 for the specific light propagation path diagram. In Figure 6, the dark solid line and dark black dashed line represent the schematic lines of light entering or coupling out of the waveguide 10; light black solid line The lines and the light black dashed lines represent the schematic diagrams of the light path located in the waveguide 10; specifically, the light black solid lines represent the first coupling-in grating 21, the first deflection grating 31 and the coupling-out grating (Figure 5- The out-coupling grating in the A direction in 1, and the A direction in Fig. 5-1 is the x-axis direction in Fig. 1); the light black dashed lines indicate that they pass through the second in-coupling grating 22 and the second deflection respectively. The light path of the grating 32 and the out-coupling grating (the out-coupling grating in the B direction in Fig. 5-2, the B direction in Fig. 5-2 is the y-axis direction in Fig. 1); more specifically, a part of the light After coupling in from the first coupling grating 21 (the first coupling grating 21 is a transmission grating), it transmits from the first coupling grating 21 into the waveguide 10, and enters the first deflection grating 31 after being totally reflected in the waveguide 10, After being deflected by the first deflection grating 31, it is reflected back to the waveguide 10, and then in the waveguide 10 After total reflection inside, it enters the coupling-out grating, and the light is coupled out through the coupling-out grating 40; the other part of the light cannot be directly coupled into the waveguide 10 and is refracted by the waveguide 10 to the second coupling-in grating 22. The entrance grating 22 is a reflection grating, and the second coupling grating 22 reflects the received light into the waveguide 10, and after being totally reflected in the waveguide 10, it enters the second deflection grating 32 and passes through the deflection of the second deflection grating 32. Then, it enters the waveguide 10 again, and after total reflection in the waveguide 10, the light is coupled out through the coupling-out grating 40.

Please refer to Figure 5. Figure 5 includes Figure 5-1 and Figure 5-2. Figure 5-1 shows the shapes of four two-dimensional periodic diffractive structures. Figure 5-2 shows the diffractive structure when it is recessed in the waveguide 10. The shape, the coupled out grating 40 is a two-dimensional periodic grating, with two mutually perpendicular grating vectors, and the corresponding two grating vectors are also perpendicular to each other; when the grating vector of the first deflection grating 31 and the positive half axis of the x-axis are different When the angle between the two is -135°, and the angle between the grating vector of the second deflection grating 32 and the positive half-axis of the x-axis is 45°, the period of the grating 40 in the positive half-axis direction of the x-axis is coupled out Equal to the period of the second coupling-in grating 22, A=Λ _x =Λ ₂ , the period of the coupling-out grating 40 in the positive half-axis direction of the y-axis is equal to the period of the first coupling-in grating 21, B=Λ _y =Λ ₁ ; Figure 5-1 lists four shapes of two-dimensional periodic diffractive structures, including: cube, pyramid, cylinder and hemispherical. The shape of the two-dimensional periodic diffractive structure then uses any one of them, but available The structure is not limited to this. The diffractive structure may protrude from the surface of the waveguide 10, or may be recessed in the waveguide 10. When recessed in the waveguide 10, it is as shown in Fig. 5-2 (it is a hemispherical cross-sectional view).

It should be noted that all directional indicators (such as up, down, inside, outside, top, bottom, etc.) in the embodiments of the present invention are only used to explain the relationship between the components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

It should also be noted that when an element is referred to as being "fixed on" or "disposed on" another element, the element may be directly on the other element or a centering element may exist at the same time. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or an intermediate element may be present at the same time.

The above are only the embodiments of the present invention. It should be pointed out here that for those of ordinary skill in the art, improvements can be made without departing from the inventive concept of the present invention, but these all belong to the present invention. The scope of protection.

Claims

A near-eye display device, which is characterized in that it comprises a waveguide and a coupling grating, a deflection grating, and a coupling-out grating arranged on the waveguide. The waveguide includes an upper surface and a lower surface arranged oppositely. The coupling grating Comprising a first coupling grating disposed on the upper surface and a second coupling grating disposed on the lower surface, the first coupling grating and the second coupling grating are directly opposite and the grating vectors are perpendicular to each other, The deflection grating includes a first deflection grating corresponding to the first coupling-in grating, and a second deflection grating corresponding to the second coupling-in grating, the deflection grating, the coupling The orthographic projections of the entrance grating and the coupling-out grating on the waveguide do not overlap each other and are spaced apart from each other, and the minimum distance between the first coupling-in grating and the first deflection grating is smaller than that of the first coupling-in grating The minimum distance between the grating and the coupling-out grating, the minimum distance between the second coupling-in grating and the second deflection grating is smaller than the distance between the second coupling-in grating and the coupling-out grating shortest distance;

The coupling-out grating is disposed on the upper surface or the lower surface, and includes coupling-out portions arranged in an array, and the coupling-out portion has a first out-coupling grating vector and a second out-coupling grating vector perpendicular to each other, so The sum of the grating vector of the first coupling-in grating, the grating vector of the first deflection grating, and the grating vector of the first coupling-out grating is equal to zero, and the grating vector of the second coupling-in grating and the second deflection grating are equal to zero. The sum of the grating vector of the grating and the grating vector of the second out-coupling grating is zero.
4. The near-eye display device of claim 1, wherein the first coupling grating and the second coupling grating have the same area and are arranged at intervals.
The near-eye display device according to claim 1 or 2, wherein the first coupling grating and the first deflection grating are both disposed on the upper surface.
The near-eye display device according to claim 3, wherein the second deflection grating is located on the upper surface.
The near-eye display device according to claim 1, wherein at least one of the coupling-in grating, the coupling-out grating, and the deflection grating is etched and formed on the waveguide.
The near-eye display device according to claim 1, wherein at least one of the coupling-in grating, the coupling-out grating, and the deflection grating is attached to the waveguide.
The near-eye display device according to claim 1, wherein the upper surface of the waveguide is close to the image source, the first coupling grating is a transmission grating, and the second coupling grating is a reflection grating.
7. The near-eye display device according to claim 7, wherein the first coupling grating has a square shape, and the orthographic projections of the first deflection grating and the second deflection grating on the upper surface are respectively located The first is coupled into adjacent two sides of the grating.
8. The near-eye display device according to claim 8, wherein the first coupling grating comprises a first side and a second side perpendicular to each other, and the first deflection grating is trapezoidal and the first The side edges are directly opposite and arranged at intervals, and the second deflection grating is directly opposite to the second side edges and arranged at intervals.
The near-eye display device according to claim 9, wherein the first deflection grating and the second deflection grating are trapezoidal or square, and a side close to the coupling grating and the coupling The grating is parallel.
The near-eye display device according to claim 1, wherein the area of the deflection grating is larger than the area of the coupling-in grating and smaller than the area of the coupling-out grating.
The near-eye display device according to claim 1, wherein the angle between the grating vector of the coupled-in grating and the grating vector corresponding to the out-coupling grating is 45°.
7. The near-eye display device according to claim 7, wherein the first coupling-in grating and the second coupling-in grating both have polarization selectivity, and the near-eye display device further comprises the first coupling-in grating and the image The polarization modulator between the sources, the light beam of the image source is modulated by the polarization modulator to output the polarization states of the first coupling-in grating and the second coupling-in grating respectively corresponding to output values.
The near-eye display device according to claim 1, wherein the coupling portions are arranged in a two-dimensional periodic arrangement, and the coupling portions are recessed and formed from the surface of the waveguide or convex from the surface of the waveguide. Out to form a bump.
The near-eye display device according to claim 14, wherein the coupling-out portion is a columnar or spherical protrusion; or the coupling-out portion is a spherical groove or a cylindrical groove.
The near-eye display device according to any one of claims 1-15, wherein the waveguide is a single-layer waveguide.