WO2023083344A1

WO2023083344A1 - Pupil expansion region and coupling-out region of modulation optical waveguide, modulation optical waveguide, and modulation method

Info

Publication number: WO2023083344A1
Application number: PCT/CN2022/131660
Authority: WO
Inventors: 黄鹏; 张雅琴; 楼歆晔
Original assignee: 上海鲲游科技有限公司
Priority date: 2021-11-15
Filing date: 2022-11-14
Publication date: 2023-05-19

Abstract

The present application provides a pupil expansion region and a coupling-out region of a modulation optical waveguide, a modulation optical waveguide, and a modulation method. The modulation optical waveguide is configured to modulate light, and comprises an optical waveguide substrate, a coupling-in region, a pupil expansion region, and a coupling-out region; the coupling-in region, the pupil expansion region, and the coupling-out region are provided on the upper surface or lower surface of the modulation optical waveguide substrate. The modulation optical waveguide satisfies at least one of the following: the pupil expansion region comprises a plurality of discrete pupil expansion sub-regions, and the plurality of discrete pupil expansion sub-regions are configured to diffract light after the light reaches the pupil expansion sub-regions, so as to modulate the density of light diffraction points in the modulation optical waveguide; and the coupling-out region comprises a plurality of discrete coupling-out sub-regions, and the plurality of discrete coupling-out sub-regions are configured to diffract light after the light reaches the coupling-out sub-regions, so as to modulate the density of diffraction points in the modulation optical waveguide.

Description

Pupil expansion area, outcoupling area, modulated optical waveguide and modulation method of modulated optical waveguide

This application claims the priority of the Chinese patent application with application number 202122795068.1 submitted to the China Patent Office on November 15, 2021, and the priority of the Chinese patent application with application number 202111346818.5 submitted to the China Patent Office on November 15, 2021 Right, the entire content of this application is incorporated in this application by reference.

technical field

The present application relates to the field of optical components, for example, it relates to a pupil-expanding region of a modulated optical waveguide, an outcoupling region, a modulated optical waveguide and a modulation method.

Background technique

Augmented Reality (Augmented Reality, AR) is a technology that combines real world and virtual information. AR display systems usually include a micro-projector and an optical display, and the pixels on the micro-projector are projected into the human eye through the optical display. , At the same time, users can see the real world through the optical display. Pico projectors provide virtual content to devices, and optical displays are often transparent optical components.

Optical waveguide is a realization path of optical display. When the refractive index of the transmission medium is greater than that of the surrounding medium and the incident angle in the waveguide is greater than the critical angle of total reflection, light can be transmitted in the waveguide without leakage and total reflection occurs. After the light from the projector is coupled into the optical waveguide, the light continues to propagate the image without loss in the waveguide until it is coupled out by the subsequent structure.

Optical waveguides on the market are usually divided into geometric array waveguides and diffractive optical waveguides. Diffractive optical waveguides are further divided into volume holographic waveguides and surface relief grating waveguides. The essence of diffractive optical waveguides is to couple incident light into waveguides through grating diffraction. , the surface relief grating waveguide has obvious advantages in many schemes because of its extremely high degree of design freedom and the mass production brought by nanoimprint processing.

The technical parameters of the AR waveguide mainly include field of view (Field Of View, FOV), viewing distance eye relief, orbital size eyebox, etc. The field of view is usually represented by a diagonal angle such as 40°, and the field of view corresponding to the 16:9 ratio frame is about 35°(H)*20°(V); the viewing distance is usually about 20-25mm, which can basically meet The wearing needs of most users, including users who wear myopia glasses; the size of the orbital orbit determines the range of free movement of the user's glasses. The larger the size, the less likely it is to lose images, so the adaptability is wider. The horizontal size of the moving eye socket needs to be able to adapt to the range of the exit pupil distance of the human eye, and give users enough margin for different horizontal wearing standards. The vertical size of the moving eye socket needs to adapt to the user's vertical wearing standard. It is generally believed that the orbital size of 15mm(H)*10mm(V) can meet the basic needs of user experience. The AR waveguide is optimized with high efficiency and good uniformity. The purpose of high efficiency is to achieve high brightness output under the same micro-projection input, so that the human eye can see the picture bright enough; uniformity includes FOV uniformity, that is, human The full field of view picture seen by the eyes has better brightness and color uniformity, including eyebox uniformity, that is, the difference in brightness received by the human eye at different positions of the eyebox (or when worn by users with different pupil distances and nose bridge heights) is as small as possible , and it is expected that different positions have better FOV uniformity.

AR waveguide technology pursues a larger viewing angle, higher efficiency, and better uniformity of the display effect. The viewing angle directly determines the size of the image that the observer can see, which is a key parameter that affects the user experience. The viewing angle The larger it is, the more vivid and specific the observation effect tends to be. For the small field of view, the state of different light transmission in the optical waveguide is not much different, and when the field of view becomes larger, the maximum field of view and the minimum field of view correspond to the light transmission in the optical waveguide (here mainly refers to The size of the reflection angle) is quite different, which will lead to the deterioration of the uniformity of different viewing angles.

Contents of the invention

The present application provides a pupil-expanding area of a modulating optical waveguide, which is configured to modulate light, and the pupil-expanding area includes a plurality of discrete pupil-expanding sub-areas, and the plurality of discrete pupil-expanding sub-areas are configured to The light is diffracted after the pupil dilation sub-region, so as to realize the modulation of the density of light diffraction points in the modulated optical waveguide.

In some embodiments, each pupil expansion sub-region is provided with a diffraction grating.

In some embodiments, the grating period is the same in multiple pupil expansion sub-regions.

In some embodiments, the location of the dilated pupil region is determined by the rays of the four bordering fields of view.

In some embodiments, the shape of each pupil dilation sub-region is one of circle, ellipse and polygon, or a figure obtained by Boolean operation of at least one of circle, ellipse and polygon.

In some embodiments, the plurality of pupil dilation sub-regions do not overlap each other.

In some embodiments, the distance between adjacent discrete pupil dilating sub-areas corresponding to the same field of view light in the pupil dilating area is less than 8mm.

In some embodiments, the dimensions of the plurality of pupil dilating sub-regions are smaller than 4.5 mm in both the horizontal and vertical directions.

In some embodiments, the depth of the grating in the pupil expansion region gradually increases along the light propagation direction, and the depth of the grating is in the range of 20nm-150nm.

The present application provides an outcoupling region of a modulated optical waveguide, which is configured to modulate light. The outcoupling region includes a plurality of discrete outcoupling subregions, and the plurality of discrete outcoupling subregions are configured to The light is diffracted after the outcoupling sub-region, so as to realize the modulation of the density of light diffraction points in the modulated optical waveguide.

In some embodiments, each outcoupling sub-region is provided with a diffraction grating.

In some embodiments, the grating period of the multiple outcoupling sub-regions is the same.

In some embodiments, the shape of each outcoupling sub-region is one of circle, ellipse and polygon, or a figure obtained by Boolean operation of at least one of circle, ellipse and polygon.

In some embodiments, the multiple outcoupling sub-regions do not overlap each other.

In some embodiments, the distance between adjacent discrete outcoupling sub-regions corresponding to the same field of view light in the outcoupling region is less than 8 mm.

In some embodiments, the dimensions of the plurality of outcoupling sub-regions in the horizontal and vertical directions are all less than 4.5 mm.

In some embodiments, the outcoupling region includes 12 or more discrete outcoupling subregions.

In some embodiments, the grating depth in the outcoupling region gradually increases along the light propagation direction, and the grating depth ranges from 50 nm to 300 nm.

The present application provides a modulating optical waveguide, which is configured to modulate light. The modulating optical waveguide includes an optical waveguide substrate, an in-coupling area, a pupil expansion area, and an out-coupling area. The in-coupling area, the pupil expansion area And the outcoupling region is arranged on the surface of the modulation optical waveguide substrate;

The modulated optical waveguide satisfies at least one of the following:

The pupil expansion area includes a plurality of discrete pupil expansion sub-areas, and the plurality of discrete pupil expansion sub-areas are configured to diffract the light after the light reaches the pupil expansion sub-area, so as to realize the Modulation of light diffraction point density;

The outcoupling region includes a plurality of discrete outcoupling subregions, and the plurality of discrete outcoupling subregions are configured to diffract the light after the light reaches the outcoupling subregion, so as to achieve the modulation Modulation of the density of light diffraction spots in an optical waveguide.

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

In some embodiments, at least one of the following is satisfied:

In the case where the pupil expansion area includes a plurality of discrete pupil expansion sub-areas, each pupil expansion sub-area is provided with a diffraction grating;

In case the outcoupling region comprises a plurality of discrete outcoupling subregions, each outcoupling subregion is provided with a diffraction grating.

In some embodiments, at least one of the following is satisfied:

In the case where the pupil expansion area includes a plurality of discrete pupil expansion sub-areas, the grating periods in the multiple pupil expansion sub-areas are the same;

In case the outcoupling region comprises a plurality of discrete outcoupling subregions, the grating period in the plurality of outcoupling subregions is the same.

In some embodiments, the position of the pupil dilating area is determined by the rays of the four border fields of view; or by the rays of the four border fields of view and multiple intermediate fields of view.

In some embodiments, at least one of the following is satisfied:

Where the pupil dilation region comprises a plurality of discrete pupil dilation sub-regions, the number of the pupil dilation sub-regions is at least 12;

In case the outcoupling region comprises a plurality of discrete outcoupling subregions, the number of the outcoupling subregions is at least 12.

In some embodiments, at least one of the following is satisfied:

In the case where the pupil dilation area includes a plurality of discrete pupil dilation sub-areas, the shape of each pupil dilation sub-area is a shape of a circle, an ellipse, and a polygon, or a shape of a circle, an ellipse, and a polygon. At least one shape obtained by Boolean operations;

In the case where the outcoupling region includes a plurality of discrete outcoupling subregions, the shape of each outcoupling subregion is one of circle, ellipse and polygon, or a combination of circle, ellipse and polygon At least one shape in is obtained by Boolean operations.

In some embodiments, at least one of the following is satisfied:

In the case where the pupil dilation area includes a plurality of discrete pupil dilation sub-areas, the multiple pupil dilation sub-areas do not overlap each other;

In the case that the outcoupling region includes a plurality of discrete outcoupling subregions, the plurality of outcoupling subregions do not overlap each other.

In some embodiments, at least one of the following is satisfied:

The distance between adjacent discrete pupil dilation sub-areas corresponding to the same field of view light in the pupil dilation area is less than 8mm;

The distance between adjacent discrete outcoupling sub-regions corresponding to the light in the same field of view of the outcoupling region is less than 8mm.

In some embodiments, at least one of the following is satisfied:

The dimensions of multiple pupil dilation sub-regions in the horizontal and vertical directions are all less than 4.5mm;

The dimensions of the plurality of outcoupling sub-regions in the horizontal and vertical directions are all less than 4.5 mm.

In some embodiments, when the pupil expansion area includes a plurality of discrete pupil expansion sub-areas, the grating depth of the pupil expansion area gradually increases along the light propagation direction, and the grating depth ranges from 20nm to 150nm .

In some embodiments, when the outcoupling region includes a plurality of discrete outcoupling subregions, the grating depth of the outcoupling region gradually increases along the direction of light propagation, and the range of the grating depth is 50nm- 300nm.

In some embodiments, the pupil dilating area and the outcoupling area are the same area, and the optical structure provided in the area is configured to perform pupil dilation and outcoupling of light at the same time.

The present application provides a modulation method for modulating an optical waveguide, and the modulating optical waveguide satisfies at least one of the following:

The pupil expansion region of the modulated optical waveguide is provided with a plurality of discrete pupil expansion subregions; the outcoupling region of the modulated optical waveguide is provided with a plurality of discrete outcoupling subregions;

The modulation method includes at least one of the following:

When the light reaches the pupil expansion area, the distance between the total reflection points of the light in the pupil expansion area is modulated by discrete pupil expansion sub-areas in the pupil expansion area;

When the light reaches the outcoupling area, the distance between the total reflection points of the light in the outcoupling pupil area is modulated by the discrete outcoupling sub-areas in the outcoupling area.

Description of drawings

Figure 1 is a schematic diagram of the propagation process and outcoupling density of light rays at different viewing angles in a modulated optical waveguide provided by an embodiment of the present application;

Fig. 2 is a schematic diagram of a diffraction angle provided by an embodiment of the present application;

Fig. 3 is a case of diffracting light rays with different viewing angles in the traditional pupil dilating area and outcoupling area provided by the embodiment of the present application;

Fig. 4 is a case of diffraction of light rays with different viewing angles in the modulated pupil expansion area provided by the embodiment of the present application;

Fig. 5 is a schematic diagram of a pupil dilation area including multiple discrete pupil dilation sub-areas provided by the embodiment of the present application according to the grating depth modulation division;

FIG. 6 is a schematic diagram of the diffraction of light rays with different viewing angles in the modulated outcoupling area provided by the embodiment of the present application;

Fig. 7 is a schematic diagram of the structure and light distribution of a modulated optical waveguide provided by the embodiment of the present application;

Fig. 8 is a schematic diagram of the outcoupling power of a modulated optical waveguide provided by an embodiment of the present application when the waveguide is not modulated;

FIG. 9 is a schematic diagram of the outcoupling power obtained after modulating the waveguide of a modulated optical waveguide provided by the embodiment of the present application;

Fig. 10 is a schematic diagram of numerical comparison of outcoupling power before and after modulation of a modulated optical waveguide at the same straight line in the outcoupling area provided by the embodiment of the present application;

FIG. 11 is a schematic flowchart of a modulation method for modulating an optical waveguide provided by an embodiment of the present application.

Detailed ways

The following description serves to disclose the present application to enable those skilled in the art to carry out the present application. The embodiments described below are by way of example only.

In the disclosure of this application, the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", " The orientation or positional relationship indicated by "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the application and simplifying the description, rather than indicating or implying A referenced device or element must have a particular orientation, be constructed, and operate in a particular orientation, so the above terms should not be construed as limiting the application.

The term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of this element can be multiple , the term "a" should not be construed as a limitation on quantity.

An embodiment of the present application provides a pupil expansion area of a modulated optical waveguide, which is configured to modulate light. The pupil expansion area includes a plurality of discrete pupil expansion sub-areas, and the multiple discrete pupil expansion sub-areas are set to The light is diffracted to realize the modulation of the density of light diffraction points in the modulated optical waveguide.

The embodiment of the present application also provides an outcoupling region of a modulated optical waveguide, which is configured to modulate light. The outcoupling region includes a plurality of discrete outcoupling subregions, and the plurality of discrete outcoupling subregions are configured to The light is diffracted after exiting the sub-region, so as to realize the modulation of the density of light diffraction points in the modulated optical waveguide.

An embodiment of the present application also provides a modulating optical waveguide, which is configured to modulate light. The modulating optical waveguide includes an optical waveguide substrate, an in-coupling area, a pupil expansion area, and an out-coupling area. The in-coupling area, the pupil expansion area, and the out-coupling area The area is set on the surface of the modulation optical waveguide substrate; the modulation optical waveguide satisfies at least one of the following: the pupil expansion area includes a plurality of discrete pupil expansion sub-areas, and the multiple discrete pupil expansion sub-areas are set to The light is diffracted to realize the modulation of the density of light diffraction points in the modulated optical waveguide; the outcoupling region includes a plurality of discrete outcoupling subregions, and the plurality of discrete outcoupling subregions are set to The light is diffracted to realize the modulation of the density of light diffraction points in the modulated optical waveguide.

As shown in Figure 1, the light emitted by the optical machine 1 first passes through the grating coupled into the area 2, and then enters the optical waveguide 3 after being diffracted. The light propagates in the optical waveguide 3 in a way of total reflection. When the light reaches the next grating area 4, it will be diffracted again. The more times of total reflection, the more times of diffraction, the larger the range of pupil expansion. It can be seen from Figure 1 that light 5 and light 6 with different viewing angles correspond to different incident angles and diffraction angles, and the size and direction of the diffraction angle are determined by the following equation:

where θ,

The definition of is shown in Figure 2, θ,

Indicates the angle of incident light, θ ₁ ,

Indicates the angle of the ray after diffracted once in the in-coupling area, and together they determine the direction of the total reflection of the ray. n ₁ is the refractive index of the waveguide material, m ₁ is the diffraction order, λ is the wavelength of light, d _x and d _y are the components of the grating period in the x and y directions respectively, satisfying d _x =d/sinθ,d _y =d/ cosθ, d is the grating period.

Due to the different diffraction angles of the light 5 and the light 6, the lateral distances traveled by them for total reflection in the waveguide are different. The distance can be expressed as z=2h×tanθ ₁ , where h is the thickness of the waveguide. The direct result of the difference in z is that the light density after pupil dilation is different. For example, the density of the outgoing light 7 is greater than the density of the outgoing light 8. When z is greater than the diameter of the pupil, the human eye may not be able to receive the light at some positions. The light at the angle of view loses part of the image information, resulting in unevenness of the angle of view. From the above analysis, it can be seen that the factor that affects the uniformity of the viewing angle is the light density in the waveguide. And the larger the field of view, the greater the difference in light density corresponding to different field of view. As shown in Figure 3, it is the light deflection situation after the light coupled into the optical waveguide passes through the in-coupling area 31 and the pupil expansion area 33, where the rectangular dots and circle dots represent the diffraction of the primary light, and the distance between the dots The distance is z, the point distance after the coupling area grating is expressed as z ₁ , the point distance after the pupil dilation area grating is expressed as z ₂ , and the point density can be regarded as the energy density. The figure shows ray 34 , ray 35 , ray 36 and ray 37 corresponding to the four boundary field angles. They all first pass through the pupil expansion area 33 , and undergo diffraction deflection to propagate to the outcoupling area 32 . In order to make the lines in the figure clear, in Fig. 3 only the case where each ray is diffracted 4 times in the transverse direction (the diffracted ray in the case of partial order diffraction is not shown) and then propagated and diffracted 2 times in the longitudinal direction is shown as a schematic illustration. In fact, the ray will Continue to perform multiple diffractions in the horizontal and vertical directions. It can be seen that, in the outcoupling area 32 , the outcoupling light densities corresponding to the four viewing angles are quite different. Comparing ray 34 and ray 37, assuming that the energy of the diffracted ray is 10% of the original after each diffraction, the two rays lose the same energy after four times of diffraction, but ray 37 travels a farther distance than ray 34. The density of the light 37 in the outcoupling region 32 is much smaller than the density of the light 34 , so the outcoupling energy corresponding to the light 37 will be lower than the outcoupling energy corresponding to the light 34 , resulting in uneven energy distribution in the field of view.

This uneven light density at the field of view may also lead to excessive diffraction of light at the front end of the pupil dilation area, and a large amount of energy is concentrated at the front end of the light propagation path, while the energy at the back end of the pupil dilation area is too low, which will cause more serious problems. The field of view is missing. Therefore, by modulating the light densities of different viewing angles to be approximately equal, the uniformity of the viewing angle can be effectively optimized.

The modulated optical waveguide structure proposed in this application is the in-coupling region+pupil expansion region+outcoupling region, wherein the optical structure set in the in-coupling area is set to realize the optical coupling function, and the optical structure set in the pupil expansion area is set to realize For the light expansion function, the optical structure set in the outcoupling area is set to realize the light outcoupling function. The light expansion function and the light outcoupling function can be realized through two mutually independent optical structures, that is, the pupil expansion area and the outcoupling area are two different areas, and the light expansion function and the light outcoupling function can also be realized through the same optical structure at the same time. That is, the dilated pupil area and the outcoupling area are the same area. In some embodiments, the light coupling-in function, the light expansion function and the light out-coupling function can also be realized simultaneously through the same optical structure.

In the following, the pupil expansion area and the outcoupling area are two different areas as examples. This structure has two modulation effects on the diffraction angle (θ). 2) Determine, it has determined the size of the total reflection point spacing _z1 ; The second time is the effect of the pupil dilation grating, which determines the size of the total reflection point spacing _z2 , and the second diffraction process is determined by the following formula:

Modulating the light density is actually modulating the size of _z1 and/or _z2 . In this application, the size of z ₁ is modulated by arranging multiple discrete pupil expansion gratings at appropriate positions in the pupil expansion area, and the size of z ₂ is modulated by arranging multiple discrete outcoupling gratings at appropriate positions in the outcoupling area. Methods as below.

As shown in FIG. 4 , firstly, an appropriate waveguide structure is selected so that the light density of the light 47 with the longest distance z ₁ is small enough to ensure that enough light can be coupled out from the outcoupling region 43 at this viewing angle. At this time, the density of diffraction points of light 44, light 45, and light 46 corresponding to the remaining viewing angles must be very large, and the position and diffraction times of the diffraction points can be controlled by reasonably selecting the position of the pupil expansion grating to reduce the remaining viewing angles Diffraction point density of light rays. In FIG. 4 , a plurality of discrete diffraction gratings of a certain size with rectangular borders are set at the light diffraction points. Of course, the borders are not limited to rectangles, and can also be in any shape such as circles and polygons. 41 is the coupling area. The final optimized pupil dilation area 42 including multiple discrete pupil dilation sub-areas is shown in FIGS. 4 and 5 . It can be understood that the pupil dilation area optimized here includes a plurality of discrete pupil dilation sub-areas, which means that the pupil dilation area also includes blank areas (areas without diffraction gratings), and the pupil dilation sub-areas can be connected or separated. The separated pupil dilation sub-areas There is white space between the regions.

In an embodiment, in order to improve the uniformity of the viewing angle, the diffraction efficiency may be modulated at different positions of the pupil dilation area after the position of the diffraction point is optimized. For example, grating height modulation can be performed on different positions of the pupil dilation area. As shown in FIG. 20nm to 150nm increases sequentially, and can be divided into more large areas according to the increase in the area of the pupil dilation area. Wherein, each large area may include one or more pupil expansion sub-areas, and one pupil expansion sub-area may also be located within one or more large areas. The grating heights of different regions increase sequentially along the direction of light propagation. Optionally, the height of the gratings in each large area is uniform. The variation of the height of the grating between adjacent large areas may be continuous, and the continuous variation here may be that the variation of the height of the grating is less than 10% or less than 5% or even 1%. Of course, the height of the grating in each large area can also increase sequentially along the direction of light propagation. So far, the magnitude modulation of z ₁ has been realized.

On the basis of z ₁ modulation, in the same way, calculate the light paths of four or more viewing angles, obtain the distribution of light in the outcoupling area, and then realize the size modulation of z ₂ . As shown in FIG. 6 , the light rays in the outcoupling region of the optical waveguide corresponding to the four boundary viewing angles are light 71 , light 72 , light 73 and light 74 . The shapes and intervals of multiple outcoupling sub-regions are reasonably selected, so that light rays with different viewing angles can obtain approximately equal outcoupling light densities, thereby improving the uniformity of the viewing angle.

In an embodiment, in order to further improve the uniformity of the viewing angle, the diffraction efficiency modulation may also be performed on different positions of the outcoupling region. For example, the grating distributed in the outcoupling area can also be depth-modulated according to the direction of light propagation, and the depth of the grating increases sequentially along the direction of light propagation, and the selection range of depth is 50nm-300nm.

As shown in FIG. 7 , FIG. 7 is a schematic diagram of the structure and light distribution of a modulation optical waveguide provided by the embodiment of the present application.

In an embodiment of the modulated optical waveguide 10 provided in the present application, the field angle of the modulated optical waveguide 10 is selected as 40°, and the selected 4 field angles are 4 boundary field angles, and the 4 boundary field angles are The distribution is (-17.5°, -10°), (-17.5°, 10°), (17.5°, -10°), (17.5°, 10°).

As shown in Figure 7, the modulated optical waveguide 10 includes an optical waveguide substrate 11, an incoupling region 110, a pupil expansion region 120 and an outcoupling region 130, wherein the incoupling region 110, the pupil expansion region 120 and the outcoupling region 130 are set On the upper surface or the lower surface of the base material 11 of the modulating optical waveguide 10, the light 20 is coupled into the modulating optical waveguide 10 from the optical machine, and first passes through the coupling area 110, and then enters the optical waveguide base material 11 in the form of total reflection after being grating. Propagate, reach the pupil expansion area 120 for multiple pupil expansion and deflection of the light 20, and finally reach the outcoupling area 130, where the light 20 is decoupled by the action of the grating.

According to the above formulas (1) and (2), the directions in which light rays 20 of four viewing angles are coupled into the modulated optical waveguide 10 can be obtained, corresponding to the first light rays 21, the second light rays 22, the third light rays 23 and the fourth light rays 24 , the solid and hollow dots and square dots in FIG. 7 all indicate the intersection of the light 20 and the waveguide surface. Calculate the total reflection position of each light 20 (that is, the intersection point between the light 20 and the surface of the modulating optical waveguide 10 ), and obtain the density of diffraction points of different light rays 20 . In this embodiment, the diffraction point density of the third light 23 corresponding to the viewing angle (17.5°, -10°) is the sparsest, and the density of the light 20 in the viewing field can be increased by adjusting the period, waveguide thickness, material refractive index, etc. . At the same time, the density of diffraction points of light 20 in the remaining three viewing fields will increase, and the distance z ₁ between the actual diffraction points of the three viewing angles is an object that needs to be controlled. The diffraction point of the third light ray 23 has been determined. As shown in Figure 7, there are three diffraction points. Three discrete pupil expansion sub-regions 1201 are set at the position of the point, and the three pupil expansion sub-regions 1201 are respectively three different sizes and shapes. oval. Wherein, a diffraction grating is arranged in the pupil expansion sub-region 1201 .

In order to allow the remaining three rays 20, i.e. the first ray 21, the second ray 22 and the fourth ray 24 to be diffracted three times to obtain three diffraction points with approximately equal densities, it is necessary to carry out corresponding positions in the pupil dilating area 120. modulation. Therefore, the positions of three diffraction points on the first light ray 21 are selected to set the pupil expansion sub-region 1201 . At the appropriate positions of the second light ray 22 and the fourth light ray 24 , the positions of three diffraction points are also selected to set the pupil expansion sub-region 1201 . The plurality of pupil dilation sub-regions 1201 may communicate with each other. As shown in FIG. 8 , although there is total reflection at the position of the no-grating area except for a plurality of pupil-expanding sub-areas 1201 in the pupil expansion area 120, there is no diffraction effect, and the point where the light ray 20 reaches the no-grating area is total reflection. The reflection point is not the diffraction point, so the light 20 will continue to propagate along the original direction without diffraction deflection, so the propagation of the light 20 in the non-grating area can be regarded as no energy loss.

As shown in FIG. 7 , the boundaries of the modulated pupil dilation sub-areas 1201 form a quadrilateral area, that is, the optimized pupil dilation area 120 . Optionally, the pupil dilating area 120 can be divided into four areas with equal areas along the direction of light propagation, wherein the grating depths of the four areas are 60nm, 80nm, 100nm and 120nm in sequence from left to right. The areas may be the same or different.

As shown in FIG. 7 , the light 20 propagates toward the outcoupling region 130 after being diffracted in the quadrangular region. It can be seen that three diffracted rays 20 of the light rays 20 at the four viewing angles propagate toward the outcoupling region 130 , and their lateral densities are approximately equal. By setting the positions of a plurality of discrete outcoupling sub-regions 1301 , the longitudinal density of the outcoupling light 20 can be adjusted, that is, the spacing z ₂ of the diffraction points of the light 20 in the outcoupling region 130 can be adjusted. A plurality of rectangular outcoupling sub-regions 1301 are set in the outcoupling region 130, and they cover their respective corresponding outcoupling diffraction points, and there may be communication between the plurality of outcoupling subregions 1301, resulting in finally including a plurality of discrete outcoupling subregions Region 1301 is coupled out of region 130 .

In this embodiment, the transmission of the light 20 at the boundary field angle (17.5°, 10°) is simulated, and the outcoupling power of the light 20 at different positions (17.5°, 10°) in the outcoupling area 130 is calculated. As shown in Figure 8, Figure 8 is a schematic diagram of the outcoupling power of the viewing angle obtained when a modulated optical waveguide provided by the embodiment of the present application is not modulated, the horizontal and vertical coordinates in Figure 8 indicate different positions, and Figure 9 A schematic diagram of the outcoupling power of a modulated optical waveguide obtained after modulating the waveguide provided for the embodiment of the present application, that is, the outcoupling power of the viewing angle obtained by using the modulated waveguide, and its value is normalized, whichever The values at the dotted line are analyzed, and Figure 10 is obtained. It can be seen from Fig. 10 that the outcoupling power of the viewing angle increases after the optical waveguide is modulated.

The results show that the modulated optical waveguide 10 provided by the present application modulates the outcoupling energy of multiple viewing angles, that is, increases the energy of the viewing angles with low coupling efficiency, so that the energy of the modulated viewing angles (that is, (17.5°, 10°) in this example) reaches the same or similar degree as other viewing angles.

In an embodiment of the modulated optical waveguide 10 provided in the present application, only light rays 20 with four viewing angles are shown for the sake of simplifying the schematic diagram. In fact, the field of view analyzed can be 5, 6 or even more. Often, the more field of view angles are analyzed, the more accurate the positioning of the sub-region is, and the smaller the area of the sub-region is.

In addition, in an embodiment of the modulated optical waveguide 10 provided in the present application, the pupil expansion region 120 and the outcoupling region 130 in the modulated optical waveguide 10 simultaneously perform multiple pupil expansion subregions 1201 and multiple outcoupling subregions 1301 set up. In fact, for the case of a small viewing angle, only setting a plurality of pupil expansion sub-regions 1201 or only setting a plurality of outcoupling sub-regions 1301 can also achieve the purpose of homogenizing the viewing angle.

In addition, in an embodiment of the modulated optical waveguide 10 provided in the present application, the modulated optical waveguide 10 includes an optical waveguide with three functional areas: an incoupling region 110 , a pupil expansion region 120 and an outcoupling region 130 . In addition, the modulated optical waveguide 10 described in this application is also suitable for waveguide structures with more functional areas, such as 4, 5 or even more functional areas.

In the modulated optical waveguide 10 described in this application, the modulated optical waveguide 10 can be configured not only for the transmission of monochrome images, but also for the transmission of color images.

In addition, in an embodiment of the modulated optical waveguide 10 provided in this application, the incoupling region 110 is provided with a sawtooth grating, a helical grating or a rectangular grating, so as to achieve the effect of coupling in the light 20; the pupil dilation region 120 is provided with a diffraction The grating, so as to play the role of pupil expansion; the outcoupling region 130 is provided with a diffraction grating, so as to play the role of pupil expansion and outcoupling at the same time. Wherein, the number of the pupil expansion area may be one or more than one, and the outcoupling area may be one or more than one.

The grating periods in the multiple pupil expansion sub-areas 1201 in the pupil expansion area 120 are the same, and the position of the pupil expansion area 120 is determined by the light rays 20 of the four fields of view. For example, the 4 fields of view here are 4 boundary fields of view of the full field of view.

In an embodiment, the position of the pupil dilating area 120 may also be determined by the rays 20 of multiple fields of view, wherein the multiple fields of view are, for example, four boundary fields of view and multiple intermediate fields of view.

In an embodiment of the modulated optical waveguide 10 provided in the present application, the shapes of the multiple pupil expansion sub-regions 1201 include but are not limited to circles, ellipses, or polygons, and their shapes obtained through Boolean operations.

In one embodiment, the plurality of pupil expansion sub-regions 1201 do not overlap each other. Wherein, the distance between adjacent discrete pupil dilating sub-areas corresponding to the same field of view ray 20 in the pupil dilating area 120 is less than or equal to the first preset size. Since the distance between the discrete pupil dilation sub-regions corresponding to the same field of view light is larger, the energy will be sparser. When reducing the density of a certain field of view light through the setting of discrete pupil dilation sub-regions, care should be taken not to make the light too sparse and cause the overall When the brightness becomes low or bright and dark stripes appear, the value of the first preset size can be determined according to the required energy value of the application scene, for example, it can be 8mm.

The pupil dilation area 120 includes at least 12 or more discrete pupil dilation sub-areas. When the area of the pupil dilation area is constant, the more divided areas, the denser the outgoing rays will be.

The size and shape of the plurality of pupil expansion sub-regions 1201 may be set to be the same or different.

The sizes of the plurality of pupil expansion sub-regions 1201 in the horizontal and vertical directions are all smaller than the second preset size. The size limitation of the pupil dilation sub-region 1201 in the horizontal and vertical directions is used to ensure that the pupil dilation sub-region only acts on the desired field of view diffraction point, so the second preset size can be based on the position of the desired field of view diffraction point in the application scenario and the desired The distance between the field diffraction point and the undesired field diffraction point is set. The value of the second preset size can be determined according to the required energy value of the application scene, such as 4.5mm.

The grating depth in the pupil expansion area 120 gradually increases along the propagation direction of the light 20 , and the grating depth ranges from 20 nm to 150 nm. This setting can enhance the uniformity of EYEBOX.

In an embodiment of the modulated optical waveguide 10 provided in the present application, the grating periods of the multiple outcoupling sub-regions 1301 are the same. The positions of the multiple outcoupling sub-regions 1301 are determined by the positions of the pupil dilating regions 120 and the corresponding directions of the light rays 20 .

The area shapes of the plurality of outcoupling sub-areas 1301 include, but are not limited to, circles, ellipses, polygons, and figures obtained through Boolean operations. Wherein, the multiple outcoupling sub-regions 1301 do not overlap with each other.

In an embodiment of the modulated optical waveguide 10 provided in the present application, the distance between adjacent discrete outcoupling sub-regions corresponding to the same field of view light 20 in the outcoupling region 130 is less than 8 mm. Wherein, the dimensions of the plurality of outcoupling sub-regions 1301 in the horizontal and vertical directions are all smaller than 4.5 mm.

In one embodiment, the outcoupling region 130 includes at least 12 or more discrete outcoupling subregions 1301 . The grating depth of the plurality of outcoupling sub-regions 1301 increases gradually along the propagation direction of the light 20 , and the grating depth ranges from 50 nm to 300 nm.

The sizes and shapes of the plurality of outcoupling sub-regions 1301 are set to be the same or different.

The pupil expansion area, the outcoupling area and the modulation optical waveguide provided by the application, the pupil expansion area and the outcoupling area of the modulation optical waveguide can increase the uniformity of the field angle of the optical waveguide; the pupil expansion area and coupling The output area realizes the modulation of the density of light diffraction points in the optical waveguide by setting discrete areas, and finally realizes that the light of different viewing angles can be emitted uniformly, thereby forming a more uniform image; the modulated optical waveguide can be applied to different ranges of viewing angles , both have improved display performance, so as to achieve effective modulation of the uniformity of the viewing angle; the pupil expansion area and the outcoupling area of the optical waveguide can simultaneously set the sub-areas for the pupil expansion area and the outcoupling area, so as to achieve uniformity The purpose of the field of view; the outcoupling area can only set a plurality of discrete sub-areas for the outcoupling area according to the actual situation, so that the uniformity of the field of view angle of the outgoing light is improved; the pupil expansion area and the outcoupling area of the optical waveguide can be The positions of the pupil expansion area and the outcoupling area are designed more finely, so as to realize the control of the light density of different viewing angles, so that the uniformity of the viewing angle of the light coupled out from the optical waveguide into the human eye is better; The discontinuous grating is used in the output area, on the one hand, it can reduce the overall area of the grating and save the master preparation time; appear brighter; the pupil dilation region and the outcoupling region of the light guide modulate the light density by modulating the distance between total reflection points in the pupil dilation region and/or the distance between total reflection points in the outcoupling region Modulation, so that the uniformity of the viewing angle of the light entering the human eye from the modulation optical waveguide is improved.

As shown in Figure 11, the present application provides a modulation method for modulating an optical waveguide, and the modulation method for modulating an optical waveguide includes steps:

1001: Setting a plurality of discrete pupil-expanding sub-regions 1201 in the pupil-expanding region 120 of the optical waveguide.

1002: Modulate the distance between the total reflection points of the light 20 in the pupil expansion area 120 through the discrete pupil expansion sub-areas 1201 in the pupil expansion area 120 .

In one embodiment, the modulation method of the optical waveguide includes the steps of:

1003: Setting a plurality of discrete outcoupling subregions 1301 in the outcoupling region 130 of the optical waveguide. 1004: Modulating light 20 through the outcoupling subregions 1301 in the outcoupling region 130 in the outcoupling region 130 The spacing between total reflection points of .

In addition, those skilled in the art can deform or adjust the shape and structure of the in-coupling region, pupil-expanding region and out-coupling region in the modulated optical waveguide according to the actual situation, such as setting them into irregular shapes, etc., as long as the On the basis of applying for the above disclosure, adopting the same or similar technical solutions as this application, solving the same or similar technical problems as this application, and achieving the same or similar technical effects as this application, all belong to the protection of this application Within the scope, the specific embodiments of the present application are not limited thereto.

In the description of this specification, reference to the terms "one embodiment", "some embodiments", "example", "example", or "some examples" means that specific features described in connection with the embodiment or example, A structure, material or characteristic is included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the described features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without conflicting with each other.

Claims

A pupil expansion area of a modulating optical waveguide, configured to modulate light, the pupil expansion area includes a plurality of discrete pupil expansion sub-areas, and the plurality of discrete pupil expansion sub-areas are configured to The light is then diffracted to realize the modulation of the density of light diffraction points in the modulated optical waveguide.
The pupil expansion region of the modulated optical waveguide according to claim 1, wherein each pupil expansion sub-region is provided with a diffraction grating.
The pupil expansion region of the modulated optical waveguide according to claim 2, wherein the grating periods in the plurality of pupil expansion sub-regions are the same.
The pupil expansion area of the modulated optical waveguide according to claim 1, wherein the position of the pupil expansion area is determined by the light rays of the four boundary fields of view.
The pupil expansion area of the modulated optical waveguide according to claim 1, wherein the shape of each pupil expansion sub-area is a shape of a circle, an ellipse, and a polygon, or at least one of a circle, an ellipse, and a polygon A shape obtained by Boolean operations.
The pupil expansion region of the modulated optical waveguide according to claim 1, wherein the plurality of pupil expansion sub-regions do not overlap with each other.
The pupil-expanding area of the modulated optical waveguide according to claim 1, wherein the distance between adjacent discrete pupil-expanding sub-areas corresponding to the same field of view light in the pupil-expanding area is less than 8 mm.
The pupil expansion area of the modulated optical waveguide according to claim 1, wherein the dimensions of the plurality of pupil expansion sub-areas in the horizontal and vertical directions are all smaller than 4.5mm.
The pupil expansion area of the modulated optical waveguide according to claim 1, wherein the depth of the grating in the pupil expansion area gradually increases along the light propagation direction, and the range of the depth of the grating is 20nm-150nm.
An outcoupling region of a modulated optical waveguide, configured to modulate light, the outcoupling region includes a plurality of discrete outcoupling subregions, and the plurality of discrete outcoupling subregions are configured to The light is diffracted after exiting the sub-region, so as to realize the modulation of the density of light diffraction points in the modulated optical waveguide.
The outcoupling region of the modulated optical waveguide according to claim 10, wherein each outcoupling subregion is provided with a diffraction grating.
The outcoupling region of the modulated optical waveguide according to claim 11, wherein the grating periods of the plurality of outcoupling subregions are the same.
The outcoupling region of the modulated optical waveguide according to claim 10, wherein the shape of each outcoupling subregion is one of circle, ellipse and polygon, or one of circle, ellipse and polygon. At least one shape obtained by Boolean operations.
The outcoupling region of the modulated optical waveguide according to claim 10, wherein the plurality of outcoupling subregions do not overlap each other.
The outcoupling region of the modulated optical waveguide according to claim 10, wherein the distance between adjacent discrete outcoupling sub-regions corresponding to the light in the same field of view in the outcoupling region is less than 8 mm.
The outcoupling region of the modulated optical waveguide according to claim 10, wherein the dimensions of the plurality of outcoupling subregions in the horizontal and vertical directions are all smaller than 4.5mm.
The outcoupling region of a modulated optical waveguide according to claim 10, wherein the outcoupling region comprises at least 12 discrete outcoupling sub-regions.
The outcoupling region of the modulated optical waveguide according to claim 10, wherein the depth of the grating in the outcoupling region gradually increases along the light propagation direction, and the depth of the grating is in the range of 50nm-300nm.
A modulating optical waveguide, configured to modulate light, the modulating optical waveguide includes an optical waveguide substrate, an incoupling region, a pupil expanding region and an outcoupling region, the incoupling region, the pupil expanding region and the The outcoupling region is arranged on the surface of the modulation optical waveguide substrate;

The modulated optical waveguide satisfies at least one of the following:

The pupil expansion area includes a plurality of discrete pupil expansion sub-areas, and the plurality of discrete pupil expansion sub-areas are configured to diffract the light after the light reaches the pupil expansion sub-area, so as to realize the Modulation of light diffraction point density;

The outcoupling region includes a plurality of discrete outcoupling subregions, and the plurality of discrete outcoupling subregions are configured to diffract the light after the light reaches the outcoupling subregion, so as to achieve the modulation Modulation of the density of light diffraction spots in an optical waveguide.
The modulated optical waveguide according to claim 19, wherein the coupling region is provided with a sawtooth grating, a helical grating or a rectangular grating.
The modulated optical waveguide according to claim 19, which satisfies at least one of the following:

In the case where the pupil expansion area includes a plurality of discrete pupil expansion sub-areas, each pupil expansion sub-area is provided with a diffraction grating;

In case the outcoupling region comprises a plurality of discrete outcoupling subregions, each outcoupling subregion is provided with a diffraction grating.
The modulated optical waveguide according to claim 21, which satisfies at least one of the following:

In the case where the pupil expansion area includes a plurality of discrete pupil expansion sub-areas, the grating periods in the multiple pupil expansion sub-areas are the same;

In case the outcoupling region comprises a plurality of discrete outcoupling subregions, the grating periods in the plurality of outcoupling subregions are the same.
The modulated optical waveguide according to claim 19, wherein the position of the pupil dilating area is determined by the light rays of the four boundary fields of view; or by the light rays of the four boundary fields of view and a plurality of intermediate fields of view.
The modulated optical waveguide according to claim 23, which satisfies at least one of the following:

Where the pupil dilation region comprises a plurality of discrete pupil dilation sub-regions, the number of the pupil dilation sub-regions is at least 12;

In case the outcoupling region comprises a plurality of discrete outcoupling subregions, the number of the outcoupling subregions is at least 12.
The modulated optical waveguide according to claim 19, which satisfies at least one of the following:

In the case where the pupil dilation area includes a plurality of discrete pupil dilation sub-areas, the shape of each pupil dilation sub-area is a shape of a circle, an ellipse, and a polygon, or a shape of a circle, an ellipse, and a polygon. At least one shape obtained by Boolean operations;

In the case where the outcoupling region includes a plurality of discrete outcoupling subregions, the shape of each outcoupling subregion is one of circle, ellipse and polygon, or a combination of circle, ellipse and polygon At least one shape in is obtained by Boolean operations.
The modulated optical waveguide according to claim 19, which satisfies at least one of the following:

In the case where the pupil dilation area includes a plurality of discrete pupil dilation sub-areas, the multiple pupil dilation sub-areas do not overlap each other;

In the case that the outcoupling region includes a plurality of discrete outcoupling subregions, the plurality of outcoupling subregions do not overlap each other.
The modulated optical waveguide according to claim 19, which satisfies at least one of the following:

The distance between adjacent discrete pupil dilation sub-areas corresponding to the same field of view light in the pupil dilation area is less than 8mm;

The distance between adjacent discrete outcoupling sub-regions corresponding to the light in the same field of view of the outcoupling region is less than 8 mm.
The modulated optical waveguide according to claim 19, which satisfies at least one of the following:

The dimensions of multiple pupil dilation sub-regions in the horizontal and vertical directions are all less than 4.5mm;

The dimensions of the plurality of outcoupling sub-regions in the horizontal and vertical directions are all less than 4.5 mm.
The modulated optical waveguide according to claim 21, wherein, in the case that the pupil dilation region includes a plurality of discrete pupil dilation sub-regions, the grating depth of the pupil dilation region gradually increases along the light propagation direction, and the grating The depth ranges from 20nm-150nm.
The modulated optical waveguide according to claim 21, wherein, when the outcoupling region comprises a plurality of discrete outcoupling subregions, the grating depth of the outcoupling region gradually increases along the light propagation direction, the The grating depth ranges from 50nm-300nm.
The modulated optical waveguide according to claim 19, wherein the pupil expansion area and the outcoupling area are the same area, and the optical structure arranged in the area is configured to perform pupil expansion and outcoupling of light at the same time.
A modulation method for modulating an optical waveguide, where the modulated optical waveguide satisfies at least one of the following:

The pupil expansion region of the modulated optical waveguide is provided with a plurality of discrete pupil expansion subregions; the outcoupling region of the modulated optical waveguide is provided with a plurality of discrete outcoupling subregions;

The modulation method includes at least one of the following:

When the light reaches the pupil expansion area, the distance between the total reflection points of the light in the pupil expansion area is modulated by discrete pupil expansion sub-areas in the pupil expansion area;

When the light reaches the outcoupling area, the distance between the total reflection points of the light in the outcoupling pupil area is modulated by the discrete outcoupling sub-areas in the outcoupling area.