CN221631787U - Diffraction beam expanding device and AR head-up display device - Google Patents

Abstract

The utility model discloses a diffraction beam expanding device and AR head-up display equipment, which comprise a waveguide plate, wherein an entrance pupil area, a pupil expanding area and an exit pupil area are arranged on the waveguide plate; the entrance pupil area and the expansion pupil area are arranged above the waveguide plate side by side, the exit pupil area is arranged below the expansion pupil area, and the length of the exit pupil area is larger than that of the expansion pupil area; the entrance pupil area and the expansion pupil area adopt one-dimensional diffraction gratings, and the exit pupil area adopts two-dimensional diffraction gratings. According to the utility model, the entrance pupil area and the pupil expansion area adopting the one-dimensional diffraction grating are arranged above the waveguide plate side by side, and the exit pupil area adopting the two-dimensional diffraction grating and having a size larger than that of the pupil expansion area is arranged below the waveguide plate, so that the utilization rate of the waveguide plate area and the optical machine efficiency is improved, and the brightness and uniformity of the size and the display effect of the eye box are improved, so that the AR head-up display device can simultaneously have higher image quality, resolution, brightness, larger field angle and larger eye box.

Description

Diffraction beam expanding device and AR head-up display device

Technical Field

The utility model relates to the technical field of display equipment, in particular to a diffraction beam expanding device and AR head-up display equipment.

Background

The information fusion method provided by the AR (Augmented Reality ) technology can combine virtual information with the real world, and enhance the perception of the real world by performing simulation on virtual information such as characters, images and the like generated by a computer and applying the virtual information to the real world, so that a user can obtain supplement and enrichment of the virtual information in the real world at the same time. In recent years, development of the automobile industry promotes further application of AR technology, and HUD (Head Up Display) technology in the AR technology is also a popular product in the automobile industry, so that the AR technology has great market value and prospect.

In HUD technology, the optical waveguide HUD has become an important direction of future development by virtue of the ultrathin structure and two-dimensional pupil expansion capability of the planar optical waveguide. The most competitive characteristic parameters for HUD technology are the size of the field angle (FOV, field ofView) and the size of the Eye box (Eye-box). However, due to the manufacturing difficulty of the large-size optical waveguide, it is difficult for the conventional optical waveguide HUD to have a larger angle of view and eye box size while ensuring higher image quality and resolution and high brightness and uniformity.

For example, in conventional diffractive optical waveguide technology, the waveguide profile with a large area of the exit pupil display region is typically composed of an entrance pupil region (i.e., coupling-in grating region), an exit pupil region, and an exit pupil region (i.e., coupling-out grating region), and the entrance pupil region, the exit pupil region, and the exit pupil region in conventional diffractive optical waveguide technology typically employ one-dimensional gratings or equivalent one-dimensional gratings. However, as shown in fig. 1, on the premise that a closed loop needs to be formed on a path of a wave vector in a waveguide theory, a conventional diffractive optical waveguide technology is limited by the area of a mydriatic zone, a technical scheme adopting a one-dimensional grating can cause that light rays of the mydriatic zone cannot be transmitted to an exit pupil zone beyond the width of the mydriatic zone, and the exit pupil zone cannot be imaged, so that the effective window area of the exit pupil zone of the diffractive optical waveguide is smaller than or equal to the width of the mydriatic zone, finally, the effective window area of the diffractive optical waveguide is very limited, the utilization efficiency of a waveguide substrate and an optical machine is relatively low, and the problems of small display size, low brightness, poor uniformity, small eyebox and the like of the diffractive optical waveguide can also occur.

Therefore, how to enable an AR head-up display device to have higher image quality, resolution, brightness, and a sufficiently large angle of view and eye box at the same time is a problem to be solved by those skilled in the art.

Disclosure of utility model

The embodiment of the utility model provides a diffraction beam expanding device and AR head-up display equipment, aiming at enabling the AR head-up display equipment to have a larger field angle and an eye box on the premise of ensuring image quality, resolution and brightness.

The embodiment of the utility model provides a diffraction beam expanding device, which comprises a waveguide plate, wherein an entrance pupil area, a pupil expanding area and an exit pupil area are arranged on the waveguide plate; the entrance pupil area and the expansion pupil area are arranged above the waveguide plate side by side, the exit pupil area is arranged below the expansion pupil area, and the length of the exit pupil area is larger than that of the expansion pupil area;

The entrance pupil area and the expansion pupil area adopt one-dimensional diffraction gratings, and the exit pupil area adopts two-dimensional diffraction gratings;

The two-dimensional diffraction grating is formed by superposing two diffraction gratings with different directions, or is formed by combining one-dimensional diffraction gratings respectively positioned on two sides of the waveguide plate.

Preferably, the direction of the grating vector of the entrance pupil area is towards the expansion pupil area, and the direction of the grating vector sum of the entrance pupil area and the expansion pupil area is towards the exit pupil area;

The one-dimensional diffraction grating and the two-dimensional diffraction grating are both surface relief gratings or volume holographic gratings.

Preferably, the included angle between the directions of two diffraction gratings in the two-dimensional diffraction gratings is 100-140 degrees;

the periods of two diffraction gratings in the two-dimensional diffraction gratings are equal.

Preferably, the entrance pupil area is located at the upper left corner of the waveguide plate, and the mydriasis area is located at the right side of the entrance pupil area;

the pupil expansion area is trapezoid, the upper bottom edge of the trapezoid is close to the entrance pupil area, and the lower bottom edge of the trapezoid is far away from the entrance pupil area.

Preferably, the two-dimensional diffraction grating of the exit pupil area is configured such that 0 th order diffracted light is transmitted forward as total reflection light within the waveguide plate, and +1 st order diffracted light is configured as coupled-out image light.

Preferably, the two-dimensional diffraction grating has a single grating profile shape including a rhomb shape, a pyramid shape, or a prism shape.

Preferably, the exit pupil area is rectangular, a first side in the rectangle is close to the mydriatic area, and the side length of the first side is larger than the length of the mydriatic area.

Preferably, any one or more of the second side, the third side and the fourth side of the rectangle is a spliced side, and the spliced side is completely or partially overlapped with the side of the waveguide plate.

Preferably, a plurality of waveguide plates are arranged, and the plurality of waveguide plates are spliced integrally according to the splicing edges.

The embodiment of the utility model also provides AR head-up display equipment, which comprises the diffraction beam expanding device.

The embodiment of the utility model discloses a diffraction beam expanding device and AR head-up display equipment, which comprise a waveguide plate, wherein an entrance pupil area, a pupil expanding area and an exit pupil area are arranged on the waveguide plate; the entrance pupil area and the expansion pupil area are arranged above the waveguide plate side by side, the exit pupil area is arranged below the expansion pupil area, and the length of the exit pupil area is larger than that of the expansion pupil area; the entrance pupil area and the expansion pupil area adopt one-dimensional diffraction gratings, and the exit pupil area adopts two-dimensional diffraction gratings; the two-dimensional diffraction grating is formed by superposing two diffraction gratings with different directions, or is formed by combining one-dimensional diffraction gratings respectively positioned on two sides of the waveguide plate. According to the embodiment of the utility model, the entrance pupil area and the pupil expansion area adopting the one-dimensional diffraction grating are arranged above the waveguide plate side by side, and the exit pupil area adopting the two-dimensional diffraction grating and having the size larger than that of the pupil expansion area is arranged below the waveguide plate, so that the utilization rate of the waveguide plate area and the optical machine efficiency is improved, the brightness and uniformity of the size and the display effect of the eye box are improved, and the display effect of the AR head-up display device can simultaneously have higher image quality, resolution, brightness and larger field angle and the eye box.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present utility model, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a grating distribution provided in the prior art;

FIG. 2 is a schematic structural diagram of a diffraction beam expander according to an embodiment of the present utility model;

FIG. 3 is a schematic diagram of grating distribution of a diffraction beam expander according to an embodiment of the present utility model;

FIG. 4 is another grating distribution diagram of a diffraction beam expander according to an embodiment of the present utility model;

FIG. 5 is a wave vector diagram of a diffraction beam expander according to an embodiment of the present utility model;

FIG. 6 is a schematic diagram illustrating the transmission of diffracted light by a diffractive beam expander according to an embodiment of the present utility model;

FIG. 7 is a schematic cross-sectional view of a diffraction beam expander according to an embodiment of the present utility model;

FIG. 8 is a schematic diagram of a rhombic grating structure of a diffraction beam expander according to an embodiment of the present utility model;

FIG. 9 is a schematic diagram of a cross section of a diamond-shaped grating of a diffraction beam expander according to an embodiment of the present utility model;

FIG. 10 is a schematic diagram of a pyramid grating structure of a diffraction beam expander according to an embodiment of the present utility model;

FIG. 11 is a schematic cross-sectional view of a pyramid grating of a diffraction beam expander according to an embodiment of the present utility model;

FIG. 12 is a schematic diagram of a prismatic grating structure of a diffraction beam expander according to an embodiment of the present utility model;

FIG. 13 is a schematic cross-sectional view of a prismatic grating of a diffraction beam expander according to an embodiment of the present utility model;

FIG. 14 is a diagram showing an exemplary splicing of waveguide plates of a diffraction beam expander according to an embodiment of the present utility model;

Fig. 15 is an application example diagram of a diffraction beam expander according to an embodiment of the present utility model.

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

It should be understood that the terms "comprises" and "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It is also to be understood that the terminology used in the description of the utility model herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model. As used in this specification and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It should be further understood that the term "and/or" as used in the present specification and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes such combinations.

Referring to fig. 2 to 3, a diffraction beam expander provided in an embodiment of the present utility model includes a waveguide plate 1, where an entrance pupil area 10, an expanded pupil area 20, and an exit pupil area 30 are disposed on the waveguide plate 1; the entrance pupil area 10 and the exit pupil area 20 are arranged above the waveguide plate 1 side by side, the exit pupil area 30 is arranged below the exit pupil area 20, and the length of the exit pupil area 30 is larger than the length of the exit pupil area 20;

Wherein, the entrance pupil area 10 and the expansion pupil area 20 both adopt one-dimensional diffraction gratings, and the exit pupil area 30 adopts two-dimensional diffraction gratings;

The two-dimensional diffraction grating is formed by superposing two diffraction gratings with different directions, or is formed by combining one-dimensional diffraction gratings respectively positioned on two sides of the waveguide plate.

In the present embodiment, by arranging the entrance pupil area 10 and the expansion pupil area 20 using the one-dimensional diffraction grating side by side above the waveguide plate 1, and arranging the exit pupil area 30 using the two-dimensional diffraction grating below the waveguide plate 1, and the length of the exit pupil area 30 is greater than that of the expansion pupil area 20, the length of the exit pupil area 30 breaks through the limit of the diffraction area length, and the area of the waveguide plate 1 is fully utilized, thereby forming a larger exit pupil area 30, and improving the angle of view and the size of the eye box; by adopting the compact layout of the entrance pupil area 10, the exit pupil area 20 and the exit pupil area 30, the possibility of stray light generated by escape of the conducted light when propagating in the waveguide plate 1 is reduced, thereby improving the uniformity of the display effect; in addition, the use of the two-dimensional diffraction grating in the exit pupil area 30 can also improve the diffraction coupling-out efficiency, and thus the utilization rate of the energy of the light, thereby improving the brightness of the display effect of the AR head-up display device, and simultaneously ensuring the image quality and resolution of the display effect of the AR head-up display device. It will be appreciated that the exit pupil area 30 includes long sides and short sides, the length of the exit pupil area 30 is specifically the projected length of the long sides of the exit pupil area 30, and similarly, the extended pupil area 20 includes long sides and short sides, and the length of the extended pupil area 20 is specifically the projected length of the long sides of the extended pupil area 20.

Specifically, as shown in fig. 3, the two-dimensional diffraction grating may be formed by stacking two diffraction gratings with different directions, and as shown in fig. 4, the two-dimensional diffraction grating may be further formed by combining a first sub-diffraction grating 31 and a second sub-diffraction grating 32 respectively located on two sides of the waveguide plate, so that the area of the upper surface and the lower surface of the upper waveguide plate 1 may be utilized, thereby improving the area utilization ratio and the display effect.

In an embodiment, the direction of the grating vector of the entrance pupil area 10 is towards the exit pupil area 30, and the direction of the grating vector sum of the entrance pupil area 10 and the exit pupil area 20 is towards the exit pupil area 20;

The one-dimensional diffraction grating and the two-dimensional diffraction grating are both surface relief gratings or volume holographic gratings.

In the present embodiment, the direction of the grating vector of the entrance pupil area 10 is toward the exit pupil area 30, the direction of the grating vector sum of the entrance pupil area 10 and the exit pupil area 20 is toward the exit pupil area 20, and the light inputted into the entrance pupil area 10 is transmitted to the exit pupil area 30 in the grating direction, and then is transmitted from the exit pupil area 30 to the exit pupil area 20 and finally is coupled out from the exit pupil area 30. In addition, the one-dimensional diffraction grating and the two-dimensional diffraction grating in the embodiment are both surface relief gratings or volume holographic gratings, and the principle of the diffraction grating deflects a light path by utilizing the diffraction effect of light and propagates light by means of total reflection. In particular, the surface relief grating has the advantages of high diffraction efficiency, compact structure and easy manufacturing, and the volume holographic grating has the advantages of high resolution, dynamic adjustability and wide spectrum application, and in a specific embodiment, the surface relief grating can be selected according to actual requirements, and in other embodiments, other grating types can be selected, and the surface relief grating or the volume holographic grating is not limited.

In one embodiment, the included angle between the directions of the two diffraction gratings in the two-dimensional diffraction grating is 100-140 degrees;

the periods of two diffraction gratings in the two-dimensional diffraction gratings are equal.

In this embodiment, two diffraction gratings among the two-dimensional diffraction gratings in the exit pupil area 30 are set to have an included angle of 100 ° to 140 °, for example, may be set at 120 °. Meanwhile, the two diffraction gratings are arranged in equal periods, so that the light energy utilization rate and the imaging quality are improved. In particular, the grating period d (i.e., the fringe spacing) and the grating direction θ of a diffraction grating may be determined by a grating vector V of the diffraction grating, which may be defined as a vector in the plane of the light diffracted by the grating, and which has a direction perpendicular to the diffraction line of the diffraction grating and an amplitude given by 2pi/d.

In a specific application scenario, the projection optical machine 40 is adopted as a light source of the diffraction beam expander, the entrance pupil area 10 on the diffraction beam expander is provided with a first diffraction grating DOE11, the pupil expander 20 is provided with a second diffraction grating DOE21, the exit pupil area 30 is provided with a third diffraction grating DOE31 and a fourth diffraction grating DOE32, wherein the first diffraction grating DOE11 and the second diffraction grating DOE21 are all one-dimensional diffraction gratings, the third diffraction grating DOE31 and the fourth diffraction grating DOE32 form a two-dimensional diffraction grating, and the third diffraction grating DOE31 and the fourth diffraction grating DOE32 respectively have a first grating vector and a second grating vector. On this basis, the projection light machine 40 emits image light beams comprising different angles of view into the entrance pupil area 10, the image light beams are coupled into the waveguide plate 1 by the DOE11 in the entrance pupil area 10 and form first guided light in the waveguide plate 1, the first guided light is guided in a first direction (X-direction) in a total internal reflection manner and propagates to the expansion pupil area 20, when the first guided light propagates to the expansion pupil area 20, the first guided light is diffracted and expanded by the DOE21 of the expansion pupil area 20, second guided light transmitted in the direction of the exit pupil area 30 is formed in the X-Y plane, and when the second guided light propagates to the exit pupil area 30, the second guided light is acted on by the first grating vector and the second grating vector together or by the first grating vector or the second grating vector alone, thereby forming at least three outgoing lights transmitted in different directions in a total internal reflection (total internal reflection, TIR) manner and the outgoing light is coupled out by the exit pupil area 30 to form output image light. It will be appreciated that the DOE21, DOE31 and DOE32 may be arranged at an angle to the X direction, and the specific size of the angle may be set according to practical requirements. In addition, the DOE31 and the DOE32 in the exit pupil area 30 can also have both the functions of expanding the pupil and the exit pupil, so that the area utilization rate of the waveguide substrate can be effectively improved.

Referring to fig. 5, an incident light ray IN1 of a specific wavelength (i.e., an image beam emitted from the projection light machine 40 to the entrance pupil area 10) may propagate along a propagation path IN the waveguide plate, where the incident light ray IN1 corresponds to the input image, and a wave vector of the incident light ray IN1 may exist IN a region BOX0 of a wave vector space defined by initial wave vectors kx and ky, and each corner of the BOX0 may represent a wave vector of light of an angular drop point of the input image.

BND1 represents a first boundary of the conducted light for satisfying total internal reflection in the waveguide plate 1; BND2 represents a second boundary of the maximum wave vector in waveguide plate 1, which may be determined by the refractive index of waveguide plate 1. Only when the wave vector of the conducted light is in the ZONE1 between BND1 and BND2, the conducted light can be waveguided in the waveguiding plate 1, and if the wave vector of the conducted light is outside ZONE1, the conducted light may leak out of the waveguiding plate 1 or not propagate at all.

In the DOE11 in the entrance pupil area 10 there is a grating vector V11, V11 with direction θ11 and magnitude 2 pi/d 11 towards the positive direction of the kx axis; the presence of a grating vector V21 in the DOE21 within the mydriatic region 20, V21 having a direction θ21 and a size 2 pi/d 21; in the DOE31 in the exit pupil area 30 there is a grating vector V31, V31 having a direction θ31 and a size 2 pi/d 31; there is a grating vector V32 in the DOE32 in the exit pupil area 30, V32 having a direction θ 32 and a magnitude 2pi/d 32. In a specific embodiment, the direction θ11 (i.e., the angle with the X-axis) of the grating vector V11 may be set to 0 °, the direction θ21 of the grating vector V21 to-135 ° (the counterclockwise rotation of the X-axis is positive and the clockwise rotation is negative), the direction θ31 of the grating vector V31 to 30 °, and the direction θ32 of the grating vector V32 to 150 °.

Here, the wavevector of the regions BOX1, BOX2, BOX3, BOX4 can be set within the region ZONE1 defined by the boundaries BND1, BND2 by setting the grating period d and the grating direction θ of the optical units DOE11, DOE21, DOE31, DOE32 such that the regions BOX0, BOX5, BOX6 in the wavevector space almost coincide, while also for the wavelengths of the three primary colors RGB (Red, green, blue). Further, the regions BOX2, BOX3, and BOX4 in the wave vector space almost coincide in the exit pupil region 30 of the waveguide plate 1.

On the basis of this, firstly, incident light IN1 enters the waveguide plate 1 from the region BOX0 and forms first conduction light B1 IN the waveguide plate 1, secondly, the first conduction light B1 is conducted to BOX1 IN the grating direction V11, then second conduction light B2 is formed IN BOX1 and conducted to BOX2 IN the direction V21, then third conduction light B3 is formed IN BOX2 and conducted to BOX3 IN the direction V32, and fourth conduction light B4 is formed IN BOX2 and conducted to BOX4 IN the direction V31, finally first output light OUT1 is formed IN BOX3 and conducted to BOX5 IN the direction V31, and second output light OUT2 is formed IN BOX4 and conducted to BOX6 IN the direction V32, whereby the output image light is coupled OUT. Wherein the wave vector of the first conducted light B1 is in the region BOX 1; the wave vector of the second conduction light B2 is in the region BOX 2; the wave vector of the third conduction light B3 is in the region BOX 3; the wave vector of the fourth conduction light B4 is in the region BOX 4; the wave vector of the first output light OUT1 is in the region BOX 5; the wave vector of the second output light OUT2 is in the region BOX 6. It can be understood that, according to the waveguide theory, the paths of the wave vectors in the waveguide plate 1 need to be closed loops to ensure the symmetrical relationship between the input and the output of the waveguide plate 1.

In an embodiment, the entrance pupil area 10 is located in the upper left corner of the waveguide plate 1, and the mydriatic area 20 is located on the right side of the entrance pupil area 10;

The mydriasis area 20 is in a trapezoid shape, the upper base of the trapezoid is close to the entrance pupil area 10, and the lower base of the trapezoid is far away from the entrance pupil area 10.

In the present embodiment, the entrance pupil area 10 is disposed at the upper left corner of the waveguide plate 1, and the mydriatic areas 20 are disposed side by side on the right side of the entrance pupil area 10, that is, the mydriatic areas 20 are disposed at the upper right corner of the waveguide plate 1. Meanwhile, the shape of the mydriatic region 20 is set to be a trapezoid, and an upper base of the trapezoid is set to be close to the entrance pupil region 10 located on the left side of the mydriatic region 20, and a lower base of the trapezoid is set to be away from the entrance pupil region 10. According to the embodiment, the expansion pupil area with the trapezoid design is adopted, so that the diffusion angle of light rays can be better controlled, more accurate light path control is realized, reflection and scattering of the light rays can be better reduced, loss and glare of the light rays are reduced, and therefore the display effect of the AR head-up display device is improved.

As shown in connection with fig. 6, in an embodiment, the two-dimensional diffraction grating of the exit pupil area 30 is provided with 0 th order diffracted light as total reflected light transmitted forward in the waveguide plate 1, and with +1 st order diffracted light as coupled-out image light.

In this embodiment, the two-dimensional diffraction grating of the exit pupil area 30 is provided with the 0 th order diffraction light and the +1 st order diffraction light, and by setting the 0 th order diffraction light to be the total reflection light and transmitting forward in the waveguide plate 1, the propagation direction and the speed of the light in the waveguide plate 1 can be ensured to be relatively stable, so that the precise control of the light path is realized, meanwhile, the +1 st order diffraction light is also set as the coupled-out image light, the coupled-out image light finally enters the eyes of the viewer after being output from the waveguide plate 1, and the +1 st order diffraction light has a larger diffraction angle relative to the 0 st order diffraction light, so that the coupling and the coupling-out of the light energy can be realized in a larger range.

As shown in connection with fig. 7-13, in one embodiment, the two-dimensional diffraction grating has a single grating profile shape, including rhombic, pyramidal, or prismatic.

In this embodiment, the two-dimensional diffraction grating in the exit pupil area 30 has a single grating distribution shape, that is, only one grating distribution shape exists on the two-dimensional diffraction grating at the same time, and the grating distribution shape may adopt any one of rhombic, pyramidal or prismatic grating distribution shapes.

Specifically, the direction of the I-I 'line is represented by an s coordinate axis on the X-Y plane, a p coordinate axis is perpendicular to the s coordinate axis and the Z coordinate axis, and then the cross section is cut according to the I-I' line. On this basis, as shown in fig. 8 to 9, when the grating distribution shape of the two-dimensional diffraction grating is a rhombic shape, the grating distribution on the exit pupil area 30 can be achieved by a rhombic grating formed on the surface of the waveguide plate 1. Similarly, as shown in fig. 10 to 11, when the grating distribution shape of the two-dimensional diffraction grating is pyramid-shaped, the grating distribution on the exit pupil area 30 can be achieved by pyramid-shaped gratings formed on the surface of the waveguide plate 1; as shown in fig. 12 to 13, when the grating distribution shape of the two-dimensional diffraction grating is prismatic, the grating distribution on the exit pupil area 30 can be achieved by a prismatic grating formed on the surface of the waveguide plate 1. Of course, the grating distribution shape adopted by the two-dimensional diffraction grating is not limited to a rhombic shape, a pyramid shape or a prismatic shape, and in other embodiments, other grating distribution shapes capable of meeting the requirements of the two-dimensional diffraction grating can be adopted, for example, a cylindrical shape, a round table shape, a prismatic table shape or a stepped shape and other grating distribution shapes can be adopted, and the difference between different grating distribution shapes is that the optical performance has a small difference.

In a specific application scenario, the occupation area estimation is performed on an 8-inch glass substrate according to the design scheme in the prior art, the ratio of the area of the exit pupil area to the area of the waveguide substrate in the prior art can be estimated to be 37.9%, while the scheme provided by the embodiment can expand the area of the exit pupil area 30, so that the length of the exit pupil area 30 is longer than that of the expanded pupil area 20, the area utilization rate of the exit pupil area 30 is improved, the ratio of the area of the exit pupil area 30 to the area of the waveguide substrate can be estimated to be 74.67% by the same method, that is, the area of the exit pupil area 30 in the embodiment is expanded by nearly twice compared with the area of the exit pupil area in the prior art, and therefore, a larger field angle and an eye box are realized.

In an embodiment, as shown in fig. 14, the exit pupil area 30 is rectangular, and a first side of the rectangle is close to the mydriatic area 20, and a side length of the first side is greater than a length of the mydriatic area 20.

Preferably, any one or more of the second side, the third side and the fourth side of the rectangle is a spliced side, and the spliced side is completely or partially overlapped with the side of the waveguide plate 1.

In this embodiment, the shape of the exit pupil area 30 is set to be rectangular, and a first side of four sides of the rectangle is set to be close to the pupil expansion area 20, and a side length of the first side is set to be longer than a length of the pupil expansion area 20, it can be understood that, in a specific application scenario, a size of a corresponding area of the exit pupil area 30 is larger than a size of a corresponding area of the pupil expansion area 20 in any direction, so that a wider light coverage can be achieved, and better visual effect and use experience are provided. Further, in the second side, the third side and the fourth side of the exit pupil area 30, any one side or multiple sides are set as splicing sides, that is, the other three sides of the exit pupil area 30 except the first side can be set as splicing sides according to different requirements in practical application occasions, and the splicing sides of the exit pupil area 30 are correspondingly set to be completely overlapped or partially overlapped with the sides of the waveguide plates 1, so that the splicing of a plurality of exit pupil areas 30 (that is, the splicing of a plurality of waveguide plates 1) is realized, and the area of the exit pupil area 30 is expanded.

In one embodiment, a plurality of waveguide plates 1 are provided, and the plurality of waveguide plates 1 are integrally spliced according to the splicing edge.

In the present embodiment, a plurality of waveguide plates 1 are provided, and the plurality of waveguide plates 1 are integrally spliced in accordance with the spliced edges of the mydriatic region 20. For example, when two waveguide plates 1 are provided, one splicing edge is correspondingly provided on each waveguide plate 1, and the two waveguide plates 1 are integrally spliced according to the corresponding splicing edges, specifically, the two waveguide plates can be spliced up and down or left and right; when four waveguide plates 1 are provided, two splicing edges can be provided on each waveguide plate 1, and the four waveguide plates 1 are integrally spliced according to an arrangement which is uniformly distributed from top to bottom and from left to right, however, other arrangements which are distributed, such as splicing the four waveguide plates 1 in sequence from left to right, and the like, are also possible. In addition, the waveguide plate 1 can be arranged in other numbers, and only the splicing edges with corresponding numbers and positions are required to be correspondingly arranged according to the required layout.

In the prior art, the conventional one-dimensional exit pupil grating waveguide solution requires that the size of the mydriatic region in the first direction is set to be greater than or equal to the size of the exit pupil region in the first direction, which results in that the joint between the waveguide plates cannot be ignored, and thus the splicing is inconvenient. In addition, in the prior art, other schemes cancel the pupil expansion area, so that the light coupled in the entrance pupil area is directly transmitted to the exit pupil area, and is expanded and coupled out, so that imaging enters human eyes. Due to the fact that the expansion pupil area is lacked, light transmission between the entrance pupil area and the exit pupil area can become uneven, brightness of the exit pupil area at a position close to the entrance pupil area is obviously higher than that of the exit pupil area at a position far away from the entrance pupil area, the entrance pupil area is also affected by transmission distance and corresponding transmission attenuation on a corresponding area in the Y-axis direction, brightness of the corresponding area is obviously higher than that of the corresponding areas on two sides, and finally the coupled-out image is obviously bright in the Y-axis direction corresponding to the entrance pupil area, image uniformity is affected, and accordingly display effect is damaged.

Compared with the prior art, the one-dimensional diffraction grating is arranged in the entrance pupil area 10 and the expansion pupil area 20, and the two-dimensional diffraction grating is arranged in the exit pupil area 30, so that the limitation that the exit pupil width needs to be smaller than or equal to the expansion pupil width in the traditional scheme can be broken through, the size and the angle of view of the eye box under the same exit pupil distance (EYE RELIEF) are expanded, and a larger window area is provided for a user. Specifically, as shown in fig. 15, in the case where the exit pupil distance is unchanged, the field angle size and the Eye box size when only one waveguide plate is set are FOV1 and Eye-box1, or FOV2 and Eye-box2, respectively, and the field angle size and the Eye box size after splicing a plurality of waveguide plates 1 are FOV3 and Eye-box3, respectively, and in this embodiment, the Eye box size and the field angle after splicing waveguide plates 1 are effectively expanded. Meanwhile, the transmission path of the light is increased by introducing the pupil expansion area, so that the transmission distribution area of the light in the waveguide plate 1 is more uniform, the uniformity of the AR head-up display device is further improved, the screen window effect of the display image is weaker, and the overall display effect is improved. In addition, compared with the prior art, the embodiment overcomes the problem of joint which cannot be ignored in the prior art, so that the plurality of waveguide plates 1 can be spliced more conveniently, and the larger eye box size under the same exit pupil distance is obtained, thereby breaking through the size limitation of the prior art, and greatly improving the display effect of the optical waveguide HUD and the possibility of floor popularization.

The embodiment of the utility model also provides AR head-up display equipment, which comprises the diffraction beam expanding device.

In a specific application scenario, the AR head-up display device in this embodiment further includes an image generator configured to generate or accept a virtual image, and an optical device for diffraction and beam expansion, and finally implement, through the image generator, combination of the virtual image and a real scenario.

In the description, each embodiment is described in a progressive manner, and each embodiment is mainly described by the differences from other embodiments, so that the same similar parts among the embodiments are mutually referred. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant points refer to the description of the method section. It should be noted that it will be apparent to those skilled in the art that various modifications and adaptations of the application can be made without departing from the principles of the application and these modifications and adaptations are intended to be within the scope of the application as defined in the following claims.

It should also be noted that in this specification, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

Claims (10)

1. The diffraction beam expander is characterized by comprising a waveguide plate, wherein an entrance pupil area, a pupil expansion area and an exit pupil area are arranged on the waveguide plate; the entrance pupil area and the expansion pupil area are arranged above the waveguide plate side by side, the exit pupil area is arranged below the expansion pupil area, and the length of the exit pupil area is larger than that of the expansion pupil area;

The entrance pupil area and the expansion pupil area adopt one-dimensional diffraction gratings, and the exit pupil area adopts two-dimensional diffraction gratings;

The two-dimensional diffraction grating is formed by superposing two diffraction gratings with different directions, or is formed by combining one-dimensional diffraction gratings respectively positioned on two sides of the waveguide plate.

2. The diffractive beam expander according to claim 1, wherein the direction of the grating vector of the entrance pupil area is towards the exit pupil area and the direction of the grating vector sum of the entrance pupil area and the exit pupil area is towards the exit pupil area;

The one-dimensional diffraction grating and the two-dimensional diffraction grating are both surface relief gratings or volume holographic gratings.

3. The diffraction beam expander of claim 1, wherein the included angle between the directions of two of the two-dimensional diffraction gratings is 100 ° to 140 °;

the periods of two diffraction gratings in the two-dimensional diffraction gratings are equal.

4. The diffractive beam expander according to claim 1, wherein the entrance pupil area is located in the upper left corner of the waveguide plate, and the expansion pupil area is located to the right of the entrance pupil area;

the pupil expansion area is trapezoid, the upper bottom edge of the trapezoid is close to the entrance pupil area, and the lower bottom edge of the trapezoid is far away from the entrance pupil area.

5. The diffractive beam expanding device according to claim 1, wherein the two-dimensional diffraction grating of the exit pupil area is provided with 0 th order diffracted light as total reflected light transmitted forward in the waveguide plate, and +1 st order diffracted light as coupled-out image light.

6. The diffractive beam expander device according to claim 1, wherein the two-dimensional diffraction grating has a single grating profile shape, the grating profile shape comprising a rhomb shape, a pyramid shape or a prism shape.

7. The diffractive beam expander according to claim 1, wherein the exit pupil area is rectangular, a first side of the rectangle being adjacent to the pupil area, a side length of the first side being larger than a length of the pupil area.

8. The diffractive beam expander device according to claim 7, wherein any one or more of the second, third and fourth sides of the rectangle is a spliced side, which is fully or partially coincident with a side of the waveguide plate.

9. The diffraction beam expander of claim 8, wherein a plurality of waveguide plates are provided, and the plurality of waveguide plates are integrally spliced according to the splicing edge.

10. An AR head-up display device comprising a diffractive beam expander device according to any one of claims 1 to 9.