CN116125583A

CN116125583A - Modulated optical waveguide and modulation method thereof

Info

Publication number: CN116125583A
Application number: CN202111346818.5A
Authority: CN
Inventors: 黄鹏; 张雅琴; 楼歆晔; 林涛
Original assignee: Shanghai Kunyou Technology Co ltd
Current assignee: Shanghai Kunyou Technology Co ltd
Priority date: 2021-11-15
Filing date: 2021-11-15
Publication date: 2023-05-16

Abstract

The invention mainly provides a modulation optical waveguide and a modulation method thereof, wherein the modulation optical waveguide is used for modulating light, and comprises at least one optical waveguide substrate, a coupling-in area, a plurality of pupil expansion areas and a plurality of coupling-out areas, wherein the coupling-in area, the pupil expansion areas and the coupling-out areas are arranged on the upper surface or the lower surface of the modulation optical waveguide substrate, the coupling-out areas comprise a plurality of discontinuous coupling-out subareas, and the light can be diffracted by the plurality of discontinuous coupling-out subareas after reaching the coupling-out areas, so that the modulation of the light diffraction point density in the modulation optical waveguide is realized.

Description

Modulated optical waveguide and modulation method thereof

Technical Field

The invention belongs to the field of optical elements, and particularly relates to a modulating optical waveguide and a modulating method thereof.

Background

Augmented Reality (AR) is a technology that merges real world and virtual information, and AR display systems typically include a micro projector and an optical display screen through which pixels on the micro projector are projected into the human eye, while the user can see the real world through the optical display screen. The micro projector provides virtual content to the device and the optical display screen is typically a transparent optical component.

An optical waveguide is one implementation path for an optical display screen. When the refractive index of the transmission medium is greater than the surrounding medium and the angle of incidence in the waveguide is greater than the critical angle for total reflection, light can be transmitted without leakage within the waveguide, and total reflection occurs. After the light from the projector is coupled into the optical waveguide, the light continues to propagate the image within the waveguide without loss until it is coupled out by a subsequent structure.

At present, optical waveguides on the market are generally classified into geometric array waveguides and diffraction optical waveguides, wherein the diffraction optical waveguides are further classified into volume holographic waveguides and surface relief grating waveguides, the essence of the diffraction optical waveguides is that incident light is coupled into the waveguides through grating diffraction, and the surface relief grating waveguides have obvious advantages in a plurality of schemes due to extremely high design freedom and mass productivity brought by nano imprinting processing.

Technical parameters of AR waveguides mainly include field angle FOV, eye relief, orbit size eyebox, etc. The angle of view is typically represented by a diagonal angle, such as 40 °, with the angle of view corresponding to a 16:9 scale being approximately 35 ° (H) by 20 ° (V); the vision distance is about 20-25mm, so that the wearing requirements of most users, including users wearing myopia glasses, can be basically met; the size of the orbit determines the range of free movement of the user's glasses, and the larger the size, the smaller the possibility of losing an image, and thus the wider the adaptability. The horizontal size of the moving orbit needs to be capable of adapting to the range of the exit pupil distance of human eyes and giving foot margin to different horizontal wearing references of users, and the vertical size of the moving orbit needs to be adaptive to the vertical wearing reference of users. It is generally believed that an orbit size of 15mm (H) by 10mm (V) may meet the basic requirements of a user experience. The AR waveguide takes high efficiency and good uniformity as optimization targets, and the purpose of the high efficiency is to realize higher brightness output under the same micro-projection input, so that the human eyes can see the picture bright enough; the uniformity comprises FOV uniformity, namely that a full-view field picture seen by human eyes has better brightness and color uniformity, and also comprises eyebox uniformity, namely that the brightness difference received by human eyes at different positions of the eyebox (or when users with different interpupillary distances and nose bridge heights wear the eyebox) is as small as possible, and the different positions are expected to have better FOV uniformity.

The AR waveguide technology pursues a display effect with a larger angle of view, higher efficiency and better uniformity, wherein the angle of view directly determines the size of an image that an observer can see, and is a key parameter affecting user experience, and the larger the angle of view, the more vivid and specific the observation effect is often. For the case of a small angle of view, the state of transmission of different light rays in the optical waveguide is not greatly different, and when the angle of view becomes large, the maximum angle of view and the minimum angle of view are greatly different for the case of transmission of light rays in the optical waveguide (herein, the size of the reflection angle is mainly referred to), so that uniformity of the different angles of view is deteriorated.

Disclosure of Invention

An advantage of the present invention is to provide a modulated optical waveguide capable of increasing uniformity of an optical waveguide viewing angle, and a modulation method thereof.

One advantage of the present invention is to provide a modulating optical waveguide and a modulating method thereof, wherein the modulating optical waveguide is provided with discontinuous areas to realize the modulation of the light diffraction point density in the optical waveguide, and finally realize the uniform emergent light of different angles of view, thereby forming a more uniform image.

An advantage of the present invention is to provide a modulation optical waveguide and a modulation method thereof, which can be applied to different ranges of view angles, and has significant improvement of display performance, thereby realizing effective modulation of uniformity of the view angle.

An advantage of the present invention is to provide a modulating optical waveguide and a modulating method thereof, wherein the modulating optical waveguide can perform sub-region arrangement on a pupil expansion region and a coupling-out region at the same time, so as to achieve the purpose of homogenizing the angle of view.

An advantage of the present invention is to provide a modulated optical waveguide and a modulation method thereof, which can provide a plurality of discontinuous sub-regions only for a coupling-out region according to actual conditions, thereby improving uniformity of an angle of view of outgoing light.

The invention has the advantages that the position of the pupil expansion area and the position of the coupling-out area can be designed more finely, so that the control of the light densities of different angles of view is realized, and the uniformity of the angles of view of the light which is finally coupled out from the optical waveguide and enters the human eyes is better.

One advantage of the present invention is to provide a modulated optical waveguide and a modulation method thereof, wherein a discontinuous grating is adopted in a coupling-out region, so that on one hand, the total area of the grating can be reduced, and the master preparation time is saved; on the other hand, the discontinuous grating can reduce the effect on the ambient light, reduce the light blocking portion, and further make the real environment look brighter.

An advantage of the present invention is to provide a modulating optical waveguide and a modulating method thereof, in which the modulating optical waveguide modulates optical density by modulating the distance between the total reflection points in the pupil expansion region and/or the distance between the total reflection points in the coupling-out region, so that the uniformity of the angle of view of the light entering the human eye from the modulating optical waveguide is improved.

To achieve at least the above advantages, the present invention provides a modulating optical waveguide for modulating light, the modulating optical waveguide comprising:

the optical waveguide substrate, the coupling-in region, the pupil expansion region and the coupling-out region, wherein the coupling-in region, the pupil expansion region and the coupling-out region are arranged on the surface of the modulation optical waveguide substrate;

the pupil expansion area comprises a plurality of discontinuous pupil expansion sub-areas, and when light reaches the pupil expansion area, the light is diffracted by the plurality of discontinuous pupil expansion sub-areas, so that the density of light diffraction points in the modulated optical waveguide is modulated; and/or the number of the groups of groups,

the coupling-out region comprises a plurality of discontinuous coupling-out subareas, and when light reaches the coupling-out region, the light is diffracted by the plurality of discontinuous coupling-out subareas, so that the density of light diffraction points in the modulated optical waveguide is modulated. .

In some of these embodiments, the coupling-in region is provided with a sawtooth grating, a helical grating or a rectangular grating.

In some of these embodiments, when the mydriatic region comprises a plurality of discrete mydriatic sub-regions, either of the mydriatic sub-regions is provided with a diffraction grating, and/or when the outcoupling region comprises a plurality of discrete outcoupling sub-regions, either of the outcoupling sub-regions is provided with a diffraction grating.

In some of these embodiments, the grating period in a plurality of the pupil sub-areas is the same when the pupil area comprises a plurality of discontinuous pupil sub-areas and/or the grating period in a plurality of the coupling-out sub-areas is the same when the coupling-out area comprises a plurality of discontinuous coupling-out sub-areas.

In some of these embodiments, the position of the mydriatic region is determined by the rays of the 4 bounding fields of view; or by rays of 4 boundary fields and multiple intermediate fields.

In some embodiments, the number of mydriatic regions is 12 or more when the mydriatic region comprises a plurality of discrete mydriatic regions, and/or the number of outcoupling regions is 12 or more when the outcoupling region comprises a plurality of discrete outcoupling regions.

In some embodiments, when the mydriatic region includes a plurality of discontinuous mydriatic sub-regions, the shape of the plurality of mydriatic sub-regions is one of square, rectangle, circle, ellipse, and polygon, or a graph obtained by performing boolean operations on at least one of square, rectangle, circle, ellipse, and polygon, and/or when the coupling-out region includes a plurality of discontinuous coupling-out sub-regions, the shape of the plurality of coupling-out sub-regions is one of square, rectangle, circle, ellipse, and polygon, or a graph obtained by performing boolean operations on at least one of square, rectangle, circle, ellipse, and polygon.

In some of these embodiments, when the mydriatic region comprises a plurality of discrete mydriatic regions, the plurality of mydriatic regions do not overlap each other, and/or when the outcoupling region comprises a plurality of discrete outcoupling sub-regions, the plurality of outcoupling sub-regions do not overlap each other.

In some embodiments, the distance between discrete areas corresponding to the same field of view light of the pupil expansion area is smaller than 8mm, and/or the distance between discrete areas corresponding to the same field of view light of the coupling-out area is smaller than 8mm.

In some embodiments, the size of the plurality of the mydriatic regions in the lateral and longitudinal directions is less than 4.5mm, and/or the size of the plurality of the coupling-out regions in the lateral and longitudinal directions is less than 4.5mm.

In some embodiments, when the mydriatic region includes a plurality of discrete mydriatic regions, the grating depth of the plurality of mydriatic regions increases gradually along the light propagation direction, ranging from 20nm to 150nm.

In some of these embodiments, when the outcoupling region comprises a plurality of discontinuous outcoupling regions, the grating depth of the plurality of outcoupling regions gradually increases along the light propagation direction, in the range of 50nm-300nm.

In some embodiments, the pupil expansion area and the coupling-out area are the same area, and the optical structure arranged in the area expands pupil and couples out light at the same time.

The invention further provides a method for modulating an optical waveguide, which modulates an optical waveguide and comprises the following steps:

when the light reaches the pupil expansion area, modulating the distance between the total reflection points in the pupil expansion area by using discontinuous pupil expansion sub-areas in the pupil expansion area; and/or the number of the groups of groups,

when the light reaches the outcoupling area, the distance between the total reflection points in the outcoupling pupil area of the light is modulated by the discontinuous outcoupling subareas in the outcoupling area.

Further objects and advantages of the present invention will become fully apparent from the following description and the accompanying drawings.

These and other objects, features and advantages of the present invention will become more fully apparent from the following detailed description and the accompanying drawings.

Drawings

FIG. 1 is a schematic diagram showing the propagation process and coupling-out density of light rays with different angles of view in an optical waveguide.

Fig. 2 is a schematic view of diffraction angles.

Fig. 3 shows the diffraction of light rays at different angles of view in a conventional pupil expansion region and coupling-out region.

Fig. 4 shows the diffraction of light rays at different angles of view in a modulated pupil-expanding region.

FIG. 5 is a schematic diagram of a grating arrangement of a plurality of non-continuous mydriatic regions.

Fig. 6 is a schematic diagram of pupil expansion area partitioned by grating depth modulation.

Fig. 7 shows the diffraction of light at different angles of view in the modulated outcoupling region.

Fig. 8 is a schematic view of an optical waveguide structure and light distribution in a first embodiment of a modulated optical waveguide according to the present invention.

Fig. 9 is a graph of the coupled-out power obtained by the optical waveguide of fig. 8 when the waveguide is not modulated.

Fig. 10 is the coupled-out power of the optical waveguide of fig. 8 after modulating the waveguide.

Fig. 11 is a numerical comparison of the power out-coupled before and after modulation of the optical waveguide of fig. 8 at the same line of the out-coupling region.

Fig. 12 is a flowchart of a first embodiment of a method for modulating an optical waveguide according to the present invention.

Detailed Description

The following description is presented to enable one of ordinary skill in the art to make and use the invention. The preferred embodiments in the following description are by way of example only and other obvious variations will occur to those skilled in the art. The basic principles of the invention defined in the following description may be applied to other embodiments, variations, modifications, equivalents, and other technical solutions without departing from the spirit and scope of the invention.

It will be appreciated by those skilled in the art that in the present disclosure, the terms "longitudinal," "transverse," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," etc. refer to an orientation or positional relationship based on that shown in the drawings, which is merely for convenience of description and to simplify the description, and do not indicate or imply that the apparatus or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore the above terms should not be construed as limiting the present invention.

It will be understood that the terms "a" and "an" should be interpreted as referring to "at least one" or "one or more," i.e., in one embodiment, the number of elements may be one, while in another embodiment, the number of elements may be plural, and the term "a" should not be interpreted as limiting the number.

As shown in fig. 1, the light coming out of the light engine 1 first passes through the grating coupled into the area 2, and after being diffracted, enters the optical waveguide 3, where the light propagates in a total reflection manner. When the light reaches the next grating region 4, diffraction occurs again, and the more the total reflection number is, the more the diffraction number is, and the larger the pupil expansion range is. As can be seen from fig. 1, the light rays 5 and 6 of different angles of view correspond to different angles of incidence and diffraction, the magnitude and direction of which are determined by the following equations:

wherein θ is,

Definition of (2) is shown in figure 2, θ,/>

Represents the angle of the incident light, θ ₁ 、/>

Indicating the angle of the light after one diffraction at the coupling-in region, which together determine the direction of propagation of the total reflection of the light. n is n ₁ Refractive index of waveguide material, m ₁ Is the diffraction order, lambda is the wavelength of light, d _x 、d _y The components of the grating period in the x and y directions respectively satisfy d _x ＝d/sinθ,d _y D/cos θ, d is the grating period.

Due to the different diffraction angles of ray 5 and ray 6, the lateral distances travelled by them in the waveguide for a total reflection are different, which distances can be expressed as z=2h×tan θ ₁ Where h is the waveguide thickness. The direct result of the difference in z is that the density of the rays after pupil expansion is different, for example, the density of the outgoing rays 7 is larger than the density of the outgoing rays 8, and when z is larger than the pupil diameter, the human eye is likely to not receive the rays with the angle of view at some positions, so that a part of image information is deleted, and the angle of view is uneven. From the above analysis, it is clear that the factor affecting the uniformity of the angle of view is the light density in the waveguide. And the larger the angle of view, the larger the light density gap corresponding to different angles of view. As shown in FIG. 3, for the light deflection of the light coupled into the light guide after passing through the pupil expansion region 33, wherein the rectangular points and the dots each represent diffraction (R-1 order) of the primary light, the distance between the points is z, and the distance between the points after grating action of the coupling region is denoted as z ₁ The point distance after the pupil-expanding region grating is denoted as z ₂ The density of points can be regarded as the density of energy. Light 34, light 35, light 36 and light 37, which correspond to the 4 boundary angles of view, are shown as they all pass through the mydriatic region 33 first and are deflected by the diffraction so as to propagate toward the outcoupling region 32. For the sake of clarity of the lines in the figure, only 4 times of lateral diffraction of each ray (the diffracted ray in the case of partial diffraction is not shown) and 2 times of longitudinal diffraction are shown in FIG. 3, and in fact, the ray will continue to be lateralMultiple diffraction is performed in the longitudinal direction. It can be seen that the density of the outcoupled light corresponding to the 4 angles of view in the outcoupling region 32 differs significantly. Comparing ray 34 with ray 37, assuming that the energy of the diffracted ray after each diffraction is 10% of the original energy, the two rays lose the same energy after four diffractions, but ray 37 travels a greater distance than ray 34. The density of the light rays 37 in the coupling-out region 32 is much smaller than that of the light rays 34, so that the coupling-out energy corresponding to the light rays 37 is lower than that corresponding to the light rays 34, resulting in uneven energy distribution at the angle of view.

Further analysis, the uneven light density in the field angle may cause excessive diffraction orders in the front end of the pupil expansion area, and a large amount of energy is concentrated in the front end of the light propagation path, while the energy in the rear end of the pupil expansion area is too low, which causes more serious field angle loss. Therefore, the light densities of the modulated different angles of view are approximately equal, and the uniformity of the angles of view can be effectively optimized.

The optical waveguide structure provided by the invention is a coupling-in area, a pupil expanding area and a coupling-out area. The optical structure arranged in the coupling-in area is used for realizing the light coupling-in function, the optical structure arranged in the pupil expansion area is used for realizing the light expansion function, and the optical structure arranged in the coupling-out area is used for realizing the light coupling-out function. It will be appreciated that the light expanding function and the light outcoupling function may be implemented by two mutually independent optical structures, i.e. the pupil expanding region and the outcoupling region are two different regions, or the light expanding function and the light outcoupling function may be implemented simultaneously by the same optical structure, i.e. the pupil expanding region and the outcoupling region are the same region. Of course, in some embodiments, the light in-coupling function, the light out-extending function, and the light out-coupling function may also be implemented simultaneously by the same optical structure.

The structure is illustrated below by two regions, the pupil expansion region and the coupling-out region being different, and the structure has two modulations of the diffraction angle (θ), the first being the coupling-in grating, determined by equations (1) and (2), which determine the total reflection point spacing z ₁ Is of a size of (2); the second time is the effect of the pupil-expanding grating, which determines the total reflection point spacing z ₂ The second diffraction process is determined by the following formulaAnd (3) determining:

modulating the light density, in effect z ₁ And/or z ₂ Is of a size of (a) and (b). The invention adopts a method of arranging a plurality of discontinuous pupil expansion gratings at proper positions of a pupil expansion area to modulate z ₁ Is modulated by providing a plurality of discontinuous outcoupling gratings at appropriate locations in the outcoupling region ₂ Is of a size of (a) and (b). The specific method is as follows.

As shown in FIG. 4, the appropriate waveguide structure is first selected to have a pitch z ₁ The light density of the longest light ray 47 is small enough to ensure that the angle of view is sufficient for the light ray to be able to be coupled out of the coupling-out region 43. At this time, the diffraction point densities of the light rays 44, 45, 46 corresponding to the remaining angles of view are necessarily large. The positions of the different diffraction points can be controlled by reasonably selecting the positions of the pupil expansion grating. In fig. 4, a diffraction grating having a rectangular boundary of a certain size is provided at the light diffraction point, and the boundary is not limited to a rectangle, and may be any shape such as a circle or a polygon. The resulting mydriatic region 42 is shown in FIG. 5.

Further, in order to improve the uniformity of the angle of view, it is necessary to perform grating height modulation on different positions of the pupil expansion region, as shown in fig. 6, to divide the pupil expansion region into 3 large areas, and the grating depth of each area along the light propagation direction sequentially increases from 20nm to 150nm, which may be divided into more areas according to the increase of the area of the pupil expansion region. To this end, realize z ₁ Is modulated by the size of (a).

In the already aligned z ₁ On the basis of modulation, the light paths of four or more angles of view are calculated in the same way to obtain the distribution of light in the coupling-out area, thereby realizing the optical coupling-out of z ₂ Is modulated by the size of (a). As shown in fig. 7. Four boundary fields of viewThe light rays at angles corresponding to the light out-coupling region of the light guide are light ray 71, light ray 72, light ray 73 and light ray 74, respectively. The shapes and the intervals of the coupling-out areas are reasonably selected, so that the light rays with different angles of view can obtain approximately equal coupling-out light ray densities, and the uniformity of the angles of view is improved.

Furthermore, the gratings distributed in the coupling-out region can be subjected to depth modulation according to the propagation direction of the light, the grating depths are sequentially increased along the propagation direction of the light, and the depth selection range is 50nm-300nm.

Fig. 8 is a schematic structural view and a schematic light distribution view of a first embodiment of the modulated optical waveguide of the present invention.

In a first embodiment of the modulated optical waveguide of the present invention, the angle of view of the modulated optical waveguide is selected to be 40 °, the 4 angles of view selected are 4 boundary angles of view, the 4 boundary angles of view being distributed (-17.5 °, -10 °), (-17.5 °,10 °), (17.5 °, -10 °), (17.5 °,10 °).

As shown in fig. 8, the modulated optical waveguide 10 includes at least one optical waveguide substrate 11, a coupling-in region 110, a plurality of pupil expansion regions 120 and a plurality of coupling-out regions 130, wherein the coupling-in regions 110, the pupil expansion regions 120 and the coupling-out regions 130 are disposed on the upper surface or the lower surface of the substrate 11 of the modulated optical waveguide 10, and the light 20 first passes through the coupling-in region 110 after being coupled into the modulated optical waveguide 10 from the optical machine, enters the optical waveguide substrate 11 after being subjected to the grating effect, propagates in a total reflection manner, reaches the plurality of pupil expansion regions 120 for a plurality of pupil expansion and light 20 deflection, and finally reaches the plurality of coupling-out regions 130, where the light 20 is subjected to the grating effect in each coupling-out region 130.

According to the above formulas (1) and (2), the directions of the light rays 20 with four angles of view coupled into the modulated optical waveguide 10 can be obtained, corresponding to the first light ray 21, the second light ray 22, the third light ray 23 and the fourth light ray 24, wherein the solid and hollow dots and square dots respectively represent the intersection points of the light rays 20 and the waveguide surface. And calculating the position of total reflection of each light ray 20 (namely the intersection point of the light ray 20 and the surface of the modulated optical waveguide 10) to obtain the intensity of diffraction points of different light rays 20. In the present embodiment, the third light ray 23 corresponding to the angle of view (17.5 °, -10 °) diffracts the dot densityThe rarest, the light ray 20 density of the field of view can be increased by adjusting the period, waveguide thickness, material refractive index, etc. At the same time, the density of diffraction points of the light rays 20 of the remaining three fields of view is further increased, and the distance z between the actual diffraction points of the three field angles ₁ Is the object that needs to be controlled. The diffraction point of the third light ray 23 has been determined, as shown in the figure, to have three diffraction points, where three discrete mydriatic areas 1201 are arranged, where the three mydriatic areas 1201 are respectively three ellipses of different sizes and shapes.

In order for the remaining three rays 20, i.e. the first ray 21, the second ray 22 and the fourth ray 24, to diffract three more times as well to obtain three diffraction points of approximately equal density, it is necessary to modulate their respective positions within the pupil expansion area 120. The setting of the amplicon region 1201 is thus performed at the location where three diffraction points are selected on the first light ray 21. The placement of the mydriatic region 1201 is also performed at the appropriate locations of the second ray 22 and the fourth ray 24 where three diffraction points are chosen. Multiple mydriatic regions 1201 may be in communication with each other. As shown in fig. 8, although there is total reflection at the position of the non-mydriatic region other than the plurality of mydriatic regions 1201 in the mydriatic region 120, there is no diffraction effect, and the point at which the light ray 20 reaches the non-mydriatic region is a total reflection point instead of a diffraction point, so that the light ray 20 continues to propagate in the original direction without diffraction deflection, and thus the propagation of the light ray 20 in the non-mydriatic region can be regarded as energy loss.

As shown in fig. 8, the boundaries of the modulated multiple mydriatic regions 1201 form a quadrilateral region, which is divided into 4 regions along the lateral direction, wherein the grating depth is 60nm, 80nm, 100nm and 120nm from left to right, and the areas of the 4 regions can be the same or different.

As shown in fig. 8, the light ray 20 propagates toward the outcoupling region 130 after being diffracted in the quadrangular region. It can be seen that the light rays 20 at the 4 angles of view each have three diffracted light rays 20 propagating toward the outcoupling region 130 with approximately equal lateral densities. The longitudinal density of the outcoupled light 20 can be adjusted by providing a plurality of discrete outcoupling regions 1301 in positionDegree, i.e. adjusting the spacing z of the diffraction points of the light 20 in the outcoupling region 130 ₂ . The coupling-out region 130 is provided with a plurality of rectangular coupling-out subregions 1301 covering the respective corresponding coupling-out diffraction points, and the coupling-out subregions 1301 may be connected to each other, resulting in a final discontinuous coupling-out region 130.

In this embodiment, the transmission of the light 20 at the boundary angle of view (17.5 ° and 10 °) is simulated, and the coupled-out powers of the light 20 at different positions (17.5 ° and 10 °) of the coupling-out region 130 are calculated. As shown in fig. 9, the output power of the angle of view obtained when the optical waveguide is not modulated is shown in different positions on the abscissa, and fig. 10 is the output power of the angle of view obtained by modulating the waveguide, and the value is normalized and analyzed by taking the value at the position of the broken line to obtain fig. 11. It can be seen from fig. 11 that the outcoupling power at this angle of view increases after the optical waveguide is modulated.

As a result, the modulated optical waveguide 10 according to the present invention modulates the energy of the coupled-out light at each angle of view, that is, increases the energy of the angle of view with low coupling-out efficiency, and thereby the energy of the modulated angle of view (i.e., (17.5 °,10 °)) is equal to or similar to that of the other angles of view.

In the first embodiment of the modulated optical waveguide 10 of the present invention, only 4 angles of view of the light rays 20 are shown for simplicity of illustration. The field of view analyzed may actually be 5, 6 or even more. The more field angles that are often analyzed, the more accurate the positioning of the sub-regions, and the smaller the area of the sub-regions.

In addition, in other embodiments of the modulated optical waveguide 10 of the present invention, the pupil area 120 and the coupling-out area 130 in the modulated optical waveguide 10 are simultaneously provided with the pupil sub-area 1201, and a plurality of coupling-out sub-areas 1301 are provided in the coupling-out area 130. In fact, for smaller angles of view, the purpose of homogenizing the angle of view can be achieved by providing only a plurality of the mydriatic regions 1201 or only a plurality of the outcoupling subregions 1301.

Furthermore, in other embodiments of the modulated optical waveguide 10 of the present invention, the modulated optical waveguide 10 includes an optical waveguide having a total of 3 functional areas, namely, the in-coupling region 110, the pupil-expanding region 120, and the out-coupling region 130. In addition, the modulated optical waveguide 10 of the present invention is also applicable to waveguide structures having more functional regions, such as 4, 5, or even more functional regions, etc.

It is emphasized that in the modulated optical waveguide 10 of the present invention, the modulated optical waveguide 10 may be used for transmission of either a monochrome image or a color image.

Furthermore, in other embodiments of the modulated optical waveguide 10 of the present invention, the coupling-in region 110 is provided with a sawtooth grating, a helical grating, or a rectangular grating, thereby functioning as a coupling-in light 20; the pupil expansion region 120 is provided with a diffraction grating, thereby playing a pupil expansion role; the out-coupling region 130 is provided with a diffraction grating, thereby functioning as both a pupil expansion and an out-coupling. The number of the pupil expansion areas can be one or more than one, and the coupling-out areas can be one or more than one.

Wherein the grating period is the same in a plurality of mydriatic sub-areas 1201 in a plurality of mydriatic areas 120, and the positions of the plurality of mydriatic areas 120 are determined by the light rays 20 of 4 fields of view. Preferably, the field of view is 4 boundary fields of view of the full field of view.

Alternatively, the positions of the plurality of pupil areas 120 may also be determined by the light rays 20 of a plurality of fields of view, preferably 4 boundary fields of view and a plurality of intermediate fields of view.

Further, in other embodiments of the modulated optical waveguide 10 of the present invention, the shape of the plurality of mydriatic regions 1201 includes, but is not limited to, square, rectangular, circular, elliptical, or polygonal, and patterns thereof that result from Boolean operations.

Preferably, the plurality of mydriatic regions 1201 do not overlap with each other. The distance between the discrete areas corresponding to the same field of view ray 20 of the plurality of pupil expansion areas 120 is smaller than the first preset size. Because the smaller the interval between the discrete areas corresponding to the light rays of the same field of view is, the denser the energy is, the specific value of the first preset size can be determined according to the required energy value of a specific application scene, for example, the specific value can be 8mm or the like.

Preferably, the plurality of mydriatic regions 120 includes at least 12 and more discrete regions. It will be appreciated that at a given pupil expansion area, the more divided areas the denser the light is emitted.

Wherein the size and shape of the plurality of mydriatic regions 1201 may be set to be the same or different.

Wherein, the size of the plurality of mydriatic sub-regions 1201 in the transverse and longitudinal directions is smaller than the second preset size. The limitation of the size of the mydriatic region 1201 in the lateral and longitudinal directions is used to ensure that the mydriatic region only acts on the expected field diffraction point, so the second preset size can be set according to the position of the expected field diffraction point and the distance between the expected field diffraction point and the unexpected field diffraction point of the specific application scene.

The grating depth of the plurality of pupil expansion regions 120 gradually increases along the propagation direction of the light ray 20, and the range is 20nm-150nm. It will be appreciated that such an arrangement may enhance uniformity of the EYEBOX.

Further, in other embodiments of the modulated optical waveguide 10 of the present invention, the grating period of the plurality of out-coupling regions 1301 is the same. The positions of the plurality of out-coupling sub-regions 1301 are determined by the positions of the plurality of pupil-expanding regions 120 and the corresponding directions of the light rays 20.

The shapes of the plurality of coupling-out sub-regions 1301 include, but are not limited to, square, rectangular, circular, elliptical, polygonal, and the patterns obtained by boolean operations. Wherein the plurality of out-coupling sub-regions 1301 do not overlap each other.

Preferably, in other embodiments of the modulated optical waveguide 10 of the present invention, the separation of discrete regions corresponding to the same field of view ray 20 of the plurality of outcoupling regions 130 is less than 8mm. Wherein the size of the plurality of out-coupling sub-regions 1301 in the lateral and longitudinal direction is smaller than 4.5mm.

Further, the plurality of out-coupling regions 130 comprises at least 12 and more discontinuous out-coupling regions 1301.

The grating depth of the plurality of out-coupling regions 1301 increases gradually along the propagation direction of the light ray 20, ranging from 50nm to 300nm.

Wherein the sizes and shapes of the plurality of out-coupling sub-regions 1301 are set to be the same or different.

As shown in fig. 12, the present invention further provides a method for modulating an optical waveguide, and in a first embodiment of the present invention, the method for modulating an optical waveguide includes the steps of:

the spacing between the total reflection points of the light rays 20 in the mydriatic region 120 is modulated by a discontinuous mydriatic sub-region 1201 in the mydriatic region 120.

Preferably, the modulation method of the optical waveguide further comprises the steps of:

the spacing between the total reflection points of the light rays 20 in the outcoupling region 130 is modulated by the outcoupling region 1301 in the outcoupling region 130.

In addition, the specific shapes and structures of the coupling-in area, the pupil expansion area and the coupling-out area in the modulated optical waveguide can be deformed or adjusted by a person skilled in the art according to practical situations, for example, the coupling-in area, the pupil expansion area and the coupling-out area are set to be irregular shapes, so long as the technical scheme which is the same as or similar to the present invention is adopted on the basis of the disclosure of the present invention, the technical problem which is the same as or similar to the present invention is solved, and the technical effect which is the same as or similar to the present invention is achieved, which falls within the protection scope of the present invention, and the specific embodiment of the present invention is not limited thereto.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

It will be appreciated by persons skilled in the art that the embodiments of the invention described above and shown in the drawings are by way of example only and are not limiting. The objects of the present invention have been fully and effectively achieved. The functional and structural principles of the present invention have been shown and described in the examples and embodiments of the invention may be modified or practiced without departing from the principles described.

Claims

1. A modulating optical waveguide for modulating light, wherein the modulating optical waveguide comprises an optical waveguide substrate, a coupling-in region, a pupil expansion region and a coupling-out region, wherein the coupling-in region, the pupil expansion region and the coupling-out region are arranged on the surface of the modulating optical waveguide substrate;

the coupling-out region comprises a plurality of discontinuous coupling-out subareas, and when light reaches the coupling-out region, the light is diffracted by the plurality of discontinuous coupling-out subareas, so that the density of light diffraction points in the modulated optical waveguide is modulated.

2. The modulated optical waveguide according to claim 1, characterized in that the coupling-in region is provided with a sawtooth grating, a skewed grating or a rectangular grating.

3. The modulated optical waveguide of claim 1, wherein when the mydriatic region comprises a plurality of discrete mydriatic sub-regions, any one of the mydriatic sub-regions is provided with a diffraction grating; and/or the number of the groups of groups,

when the outcoupling area comprises a plurality of discontinuous outcoupling sub-areas, any one of the outcoupling sub-areas is provided with a diffraction grating.

4. A modulated optical waveguide according to claim 3, wherein when the pupil area comprises a plurality of discrete pupil sub-areas, the grating periods in the plurality of pupil sub-areas are the same; and/or the number of the groups of groups,

when the out-coupling region comprises a plurality of discontinuous out-coupling sub-regions, the grating periods in the plurality of out-coupling sub-regions are the same.

5. The modulated optical waveguide of claim 1, wherein the position of the pupil expansion region is determined by the rays of the 4 bounding fields of view; or by rays of 4 boundary fields and multiple intermediate fields.

6. The modulated optical waveguide of claim 5, wherein when the mydriatic region comprises a plurality of discrete mydriatic sub-regions, the number of mydriatic sub-regions is 12 or more; and/or the number of the groups of groups,

when the outcoupling region comprises a plurality of discontinuous outcoupling sub-regions, the number of the outcoupling sub-regions is 12 or more.

7. The modulated optical waveguide of claim 1, wherein when the mydriatic region includes a plurality of discontinuous mydriatic sub-regions, the shape of the plurality of mydriatic sub-regions is one of square, rectangular, circular, elliptical, and polygonal, or a pattern obtained by boolean operation of at least one of square, rectangular, circular, elliptical, and polygonal; and/or the number of the groups of groups,

when the coupling-out region comprises a plurality of discontinuous coupling-out subareas, the shapes of the plurality of coupling-out subareas are one of square, rectangle, circle, ellipse and polygon, or a graph obtained by at least one of square, rectangle, circle, ellipse and polygon through Boolean operation.

8. The modulated optical waveguide of claim 1, wherein when the mydriatic region comprises a plurality of discrete mydriatic sub-regions, the plurality of mydriatic sub-regions do not overlap with each other; and/or the number of the groups of groups,

when the outcoupling region comprises a plurality of discontinuous outcoupling sub-regions, the plurality of outcoupling sub-regions do not overlap each other.

9. The modulated optical waveguide according to claim 1, characterized in that the pitch of the discrete areas corresponding to the same field of view rays of the pupil expansion area is smaller than 8mm and/or the pitch of the discrete areas corresponding to the same field of view rays of the coupling-out area is smaller than 8mm.

10. The modulated optical waveguide of claim 1, wherein the size of the plurality of said amplicon regions in the lateral and longitudinal directions is less than 4.5mm, and/or the size of the plurality of said coupler regions in the lateral and longitudinal directions is less than 4.5mm.

11. A modulated optical waveguide according to claim 3, characterized in that when the mydriatic region comprises a plurality of discrete mydriatic sub-regions, the grating depth of the plurality of mydriatic sub-regions increases gradually in the direction of light propagation, in the range 20nm-150nm.

12. A modulated optical waveguide according to claim 3, characterized in that when the outcoupling region comprises a plurality of discrete outcoupling regions, the grating depth of the plurality of outcoupling regions increases gradually in the direction of light propagation, in the range of 50nm-300nm.

13. The modulated optical waveguide of claim 1, wherein the pupil expansion region and the outcoupling region are the same region, and wherein the optical structures disposed in the region simultaneously pupil expansion and outcoupling of light.

14. A modulation method of modulating an optical waveguide, characterized in that a pupil area of the optical waveguide is provided with a plurality of discrete mydriatic sub-areas and/or a coupling-out area of the optical waveguide is provided with a plurality of discrete coupling-out sub-areas, the modulation method comprising the steps of: