Waveguide assembly and near-eye display device including a waveguide assembly

Abstract

A waveguide assembly comprises: a waveguide sheet; a coupling-in region provided on a surface of the waveguide sheet, the coupling-in region being configured to couple-in light; a coupling-out grating provided on a surface of the waveguide sheet, the coupling-out grating being configured to couple-out light coupled-in from the coupling-in region; and a first reflection grating provided on the same surface of the waveguide sheet as the coupling-out grating and located at the end of the coupling-out grating in the light transmission direction, the first reflection grating being parallel to the groove lines of the coupling-out grating, the first reflection grating having the same period as the coupling-out grating and the diffraction efficiency of the second-order diffracted light in the diffraction orders being set to be maximum, or the first reflection grating having half the period of the coupling-out grating and the diffraction efficiency of the first-order diffracted light in the diffraction orders being set to be maximum, the first reflection grating being configured to reflect light that has not been coupled-out by the coupling-out grating back to the coupling-out grating for coupling-out again, thereby improving the light energy utilization, the exit pupil density and the brightness uniformity, and the manufacturing process is simple.

Description

Technical Field

[0001] This application relates to the field of optical transmission technology, and more specifically to a waveguide assembly and a near-eye display device including the waveguide assembly. Background Technology

[0002] Near-eye display devices are mainly used to display images or videos to the human eye. Near-eye display devices can be widely used in fields such as virtual reality, augmented reality, mixed reality, and military applications.

[0003] Near-eye display devices include components such as light source components and waveguides. The waveguides have coupling-in regions and coupling-out regions. Light emitted by the light source components is coupled into the waveguide through the coupling-in regions, and then the light is coupled out of the waveguide through the coupling-out regions and transmitted to the human eye.

[0004] However, due to the low diffraction efficiency of light in the coupling region, most of the light energy is absorbed by the sides of the waveguide or escapes at the sides, resulting in very low overall light energy utilization of the waveguide, which in turn leads to very low exit pupil density in near-eye display devices. Moreover, since the energy of light gradually weakens as it propagates in the waveguide, the brightness of the coupled light is uneven. Summary of the Invention

[0005] The main objective of this application is to provide a waveguide component with high light energy utilization, high exit pupil density, and uniform brightness, and a near-eye display device including the waveguide component.

[0006] One embodiment of this application provides a waveguide component, including:

[0007] Waveguide sheet;

[0008] A coupling region is provided on one surface of the waveguide sheet, and the coupling region is used to couple light into the waveguide sheet and allow the light to diffuse and propagate within the waveguide sheet.

[0009] A coupling grating, disposed on one surface of the waveguide sheet, is used to couple light rays coupled into the coupling region out of the waveguide sheet; and

[0010] The first reflection grating is disposed on the same surface of the waveguide sheet as the coupling grating and is located at the end of the coupling grating along the light transmission direction. The groove lines of the first reflection grating are parallel to those of the coupling grating. The first reflection grating and the coupling grating have the same period, and the diffraction efficiency of the second-order diffracted light in the diffraction order is set to the maximum. Alternatively, the first reflection grating has half the period of the coupling grating, and the diffraction efficiency of the first-order diffracted light in the diffraction order is set to the maximum. The first reflection grating is used to reflect light rays that have passed through the coupling grating but have not been coupled back to the coupling grating for coupling.

[0011] In one embodiment, the first reflection grating includes a first reflection grating and a second reflection grating that are configured in phase separation.

[0012] In one embodiment, the first reflection grating is a sinusoidal grating, a rectangular grating, a blazed grating, or a tilted grating tilted in the direction of the coupling grating.

[0013] In one embodiment, the waveguide assembly further includes a second reflection grating, which is disposed on the same surface of the waveguide sheet as the first reflection grating;

[0014] The second reflection grating is disposed opposite to the first reflection grating and is located on both sides of the coupling grating;

[0015] The groove line of the second reflection grating is parallel to the groove line of the coupling grating. The period of the second reflection grating is the same as the period of the coupling grating and the diffraction efficiency of the second-order diffraction light in the diffraction order is set to the maximum. Alternatively, the period of the second reflection grating is half the period of the coupling grating and the diffraction efficiency of the first-order diffraction light in the diffraction order is set to the maximum.

[0016] The light rays that are not coupled out after being reflected by the first reflection grating are transmitted to the second reflection grating, and are reflected back to the coupling grating by the second reflection grating.

[0017] In one embodiment, the first reflection grating includes a first reflection grating and a second reflection grating arranged in phase, and the second reflection grating includes a third reflection grating and a fourth reflection grating arranged in phase, wherein the first reflection grating and the third reflection grating are arranged opposite to each other, and the second reflection grating and the fourth reflection grating are arranged opposite to each other.

[0018] In one embodiment, the second reflection grating is a sinusoidal grating, a rectangular grating, a blazed grating, or a tilted grating tilted in the direction of the coupling grating.

[0019] In one embodiment, the coupled grating is a one-dimensional grating.

[0020] In one embodiment, the coupling grating is composed of two one-dimensional gratings respectively disposed on two surfaces of the waveguide sheet, or is composed of two one-dimensional gratings superimposed on the same surface of the waveguide sheet.

[0021] In one embodiment, the included angle between the two one-dimensional gratings of the coupled grating is 50-70 degrees.

[0022] In one embodiment, the coupled grating is a rectangular grating, a blazed grating, a tilted grating, a sinusoidal grating, or a holographic grating, with a groove depth of 50–200 nm.

[0023] In one embodiment, the first reflection grating is adjacent to the coupling grating.

[0024] In one embodiment, the width of the first reflection grating is greater than 3 mm.

[0025] In one embodiment, the coupled grating is a rectangular grating, and the first reflection grating and / or the second reflection grating is a tilted grating or a blazed grating.

[0026] In one embodiment, the coupling region includes a coupling grating for coupling light into the waveguide sheet.

[0027] In one embodiment, the coupled grating is a rectangular grating, a blazed grating, a tilted grating, a sinusoidal grating, or a holographic grating, with a period of 300–600 nm and a groove depth of 40–500 nm.

[0028] In one embodiment, the coupling region further includes a folding grating for diffusing and transmitting light coupled from the coupling grating within the waveguide sheet.

[0029] In one embodiment, the lattice grating is a rectangular grating, a blazed grating, a tilted grating, a sinusoidal grating, or a holographic grating, with a period of 300–600 nm and a groove depth of 40–500 nm.

[0030] In one embodiment, the coupling-in region and the coupling-out grating are located on the same surface of the waveguide sheet or on two opposite surfaces of the waveguide sheet.

[0031] In one embodiment, the waveguide sheet has a thickness of 0.3 to 2.5 mm, is made of an optical material that is transparent to visible light, and has a refractive index of 1.4 to 2.2.

[0032] One embodiment of this application also provides a near-eye display device, including a projection optical engine and a waveguide assembly, wherein the waveguide assembly is the waveguide assembly described in any of the above embodiments.

[0033] Beneficial effects:

[0034] The waveguide assembly provided in this application has a first reflection grating disposed on one side surface of the waveguide sheet, with the groove lines of the first reflection grating parallel to those of the coupling grating. The first reflection grating and the coupling grating have the same period, and the diffraction efficiency of the second-order diffracted light in the diffraction order is set to the maximum. Alternatively, the period of the first reflection grating is half that of the coupling grating, and the diffraction efficiency of the first-order diffracted light in the diffraction order is set to the maximum. This allows light rays that have passed through the coupling grating but not coupled to return to the coupling grating via the first reflection grating, thus achieving coupling. This improves the overall light energy utilization of the waveguide assembly and increases the overall exit pupil density of the waveguide assembly. Furthermore, since the light rays returned and re-coupled via the first reflection grating supplement the previously coupled light rays, the brightness uniformity of the coupled light rays within the visible area of ​​the waveguide sheet is improved. Moreover, according to the optical design of this invention, only a first reflection grating needs to be disposed on one side surface of the waveguide sheet, simplifying the manufacturing process and facilitating production. Moreover, the waveguide component provided in this embodiment allows light rays that are not coupled out by the first coupling grating to return to the coupling grating only by passing through a first reflection grating, resulting in higher light energy utilization. Attached Figure Description

[0035] The advantages of the above and / or additional aspects of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0036] Figure 1 This is a schematic diagram of the structure of a waveguide component provided in an embodiment of this application;

[0037] Figure 2 for Figure 1 Side view of the waveguide assembly shown;

[0038] Figure 3 for Figure 1 The raster vector diagram of the waveguide assembly is shown below;

[0039] Figure 4 A simulation result diagram of optical diffraction of a waveguide component provided in an embodiment of this application;

[0040] Figure 5 for Figure 1 A schematic diagram of the waveguide assembly with grating vectors is shown;

[0041] Figure 6 This is a schematic diagram of the structure of a waveguide component provided in an embodiment of this application;

[0042] Figure 7 This is a schematic diagram of the structure of a waveguide component provided in an embodiment of this application;

[0043] Figure 8 This is a schematic diagram of the structure of a waveguide component provided in an embodiment of this application;

[0044] Figure 9 for Figure 8 A side view of a portion of the waveguide assembly shown;

[0045] Figure 10 for Figure 8 A raster vector diagram of the waveguide assembly shown;

[0046] Figure 11 for Figure 8 A raster vector diagram of the waveguide assembly shown;

[0047] Figure 12 for Figure 8 A raster vector diagram of the waveguide assembly shown;

[0048] Figure 13 for Figure 8 A raster vector diagram of the waveguide assembly shown;

[0049] Figure 14 This is a schematic diagram of the structure of a near-eye display device provided in an embodiment of this application;

[0050] Figure 15 This is a schematic diagram of the structure of a near-eye display device provided in an embodiment of this application.

[0051] in, Figures 1 to 15 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0052] 1. Waveguide plate; 2. Coupled-in region; 21. Coupled-in grating; 22. Turning grating; 3. Coupled-out grating; 4. First reflection grating; 41. First reflection grating; 42. Second reflection grating; 5. Second reflection grating; 51. Third reflection grating; 52. Fourth reflection grating; 6. Projection optical engine. Detailed Implementation

[0053] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0054] Example 1

[0055] Figure 1 This is a schematic diagram of the structure of a waveguide component provided in an embodiment of this application.

[0056] like Figure 1 As shown, the waveguide component provided in this embodiment includes:

[0057] Waveguide 1;

[0058] The coupling region 2 is disposed on a surface of the waveguide 1. The coupling region 2 is used to couple light into the waveguide 1 and to diffuse and transmit the light within the waveguide 1.

[0059] A coupling grating 3 is disposed on one surface of the waveguide 1. The coupling grating 3 is used to couple the light rays coupled in from the coupling region 2 out of the waveguide 1; and

[0060] The first reflection grating 4 is disposed on the same surface of the waveguide plate 1 as the coupling grating 3 and is located at the end of the coupling grating 3 along the light transmission direction. The groove lines of the first reflection grating 4 and the coupling grating 3 are parallel. The first reflection grating 4 and the coupling grating 3 have the same period and the diffraction efficiency of the second-order diffracted light in the diffraction order is set to the maximum. Alternatively, the first reflection grating 4 is half the period of the coupling grating 3 and the diffraction efficiency of the first-order diffracted light in the diffraction order is set to the maximum. The first reflection grating 4 is used to reflect the light that has passed through the coupling grating 3 but has not been coupled back to the coupling grating 3 and then coupled out again.

[0061] Figure 2 for Figure 1 Side view of the waveguide assembly shown.

[0062] like Figure 2 As shown, the working principle of the waveguide component provided in this embodiment is as follows:

[0063] Light rays are coupled into waveguide 1 from coupling region 2 and propagate through waveguide 1 to coupling grating 3. Coupling grating 3 couples light ray A out of waveguide 1, making it visible to the human eye and forming the visible area. Light ray B, which is not coupled out, continues to propagate to the first reflection grating 4. The first reflection grating 4 reflects light ray B back to coupling grating 3, and then couples it out again as light ray C. Light ray C remains parallel to light ray A.

[0064] Figure 3 for Figure 1 The grating vector diagram of the waveguide assembly is shown.

[0065] like Figure 3As shown, the coupling region 2 has a grating vector G0, the coupling grating 3 has a grating vector G1, and the first reflection grating 4 has a grating vector G2. Since the groove lines of the first reflection grating 4 and the coupling grating 3 are parallel, their grating vectors are parallel, allowing the uncoupled ray B to be reflected back to the coupling grating 3 by the first reflection grating 4. The period of the first reflection grating 4 determines its vector magnitude. Furthermore, when the period of the first reflection grating 4 is the same as the period of the coupling grating 3, the diffraction efficiency of the second-order diffracted light is set to the maximum. This results in the grating vector magnitude corresponding to the second-order diffracted light when ray B diffracts at the first reflection grating 4 being twice that of the coupling grating 3 vector, thus making grating vector G0 + G1 + G2 = 0. Ultimately, ray C is coupled out, improving light energy utilization, and the presence of ray C increases the exit pupil density. Furthermore, since the energy of light gradually decreases as it propagates in the waveguide, the uncoupled light rays are reflected back to the coupling grating 3 and partially diffracted out. The energy of this part of the light rays also gradually decreases during propagation, and its propagation direction is exactly opposite to that of light ray A in the waveguide 1. This compensates for the energy reduction of light ray A during its propagation in the waveguide 1, and improves the brightness uniformity of the coupled light rays in the entire visible area of ​​the waveguide.

[0066] When the period of the first reflection grating 4 is half the period of the coupling grating 3, the diffraction efficiency of the first-order diffracted light is set to the maximum in its diffraction order. Therefore, its vector magnitude is twice that of the coupling grating 3, which also makes the grating vector G0+G1+G2=0, thus coupling out light ray C, improving light energy utilization, and the presence of light ray C increases the exit pupil density. Furthermore, since the uncoupled light ray is reflected back to the coupling grating 3 and partially diffracted out, this part of the light ray compensates for the energy reduction of light ray A when it propagates within the waveguide 1, improving the brightness uniformity of the coupled light ray in the entire visible area of ​​the waveguide 1.

[0067] In this embodiment, since the uncoupled light rays are transmitted by total internal reflection within the waveguide 1, the first reflection grating 4 needs to be set at the end of the coupling grating 3 along the light transmission direction.

[0068] The waveguide assembly provided in this embodiment has a first reflection grating 4 disposed on one side surface of the waveguide sheet 1, and the first reflection grating 4 is parallel to the groove line of the coupling grating 3. The first reflection grating 4 and the coupling grating 3 have the same period, and the diffraction efficiency of the second-order diffracted light in the diffraction order is set to the maximum, or the first reflection grating 4 is half the period of the coupling grating 3, and the diffraction efficiency of the first-order diffracted light in the diffraction order is set to the maximum. This allows light rays that have passed through the coupling grating 3 but have not been coupled out to be returned to the coupling grating 3 by the first reflection grating 4, thereby being coupled out. This improves the overall light energy utilization rate of the waveguide assembly and increases the overall exit pupil density of the waveguide assembly. Furthermore, since the light rays returned and coupled out by the first reflection grating 4 supplement the originally coupled light rays, the brightness uniformity of the coupled light rays in the overall visible area of ​​the waveguide sheet 1 is improved. Moreover, according to the optical design of this invention, only the first reflection grating 4 needs to be disposed on one side surface of the waveguide sheet 1, making the manufacturing process simple and easy to produce. Moreover, the waveguide component provided in this embodiment allows light rays that are not coupled out by the first coupling grating 3 to return to the coupling grating 3 only by passing through a first reflection grating 4, resulting in higher light energy utilization.

[0069] Furthermore, the first reflection grating 4 is adjacent to the coupling grating 3. Since the first reflection grating 4 and the coupling grating 3 are located on the same side of the waveguide sheet 1, the waveguide assembly is simple and convenient to manufacture. In other embodiments, there is a gap between the first reflection grating 4 and the coupling grating 3; this is not specifically limited here.

[0070] In this embodiment, the width of the first reflection grating 4 is greater than 3mm, resulting in high reflection efficiency.

[0071] In this embodiment, the first reflection grating 4 is a sinusoidal grating, a rectangular grating, a blazed grating, or a tilted grating tilted towards the coupling grating 3, and the groove depth is 400–600 nm. In some preferred embodiments, the first reflection grating 4 can be a tilted grating or a blazed grating. Compared to a conventional rectangular grating, setting it as a tilted grating or a blazed grating can concentrate the diffraction energy on a certain order, improving the reflection efficiency of the first reflection grating 4, thereby improving the light energy utilization rate of the waveguide 1.

[0072] Figure 4 The simulation results of optical diffraction of a waveguide component provided in an embodiment of this application are shown in the figure.

[0073] like Figure 4As shown, taking a first reflection grating 4 with a period of 340nm, a height of 500nm, a duty cycle of 0.74, an inclination angle of 66.7° to the horizontal direction, and a refractive index of 1.7 for both the first reflection grating 4 and the waveguide sheet, and a wavelength of 460nm as an example, its highest diffraction efficiency can reach over 95%, with an average of about 75%, which can significantly improve the energy utilization rate of the waveguide sheet 1.

[0074] More preferably, the first reflection grating 4 is an inclined grating tilted towards the direction of the coupling grating 3, in which case the second-order diffracted light has a high diffraction efficiency, and in some embodiments, its second-order diffraction efficiency is greater than 80%.

[0075] In this embodiment, the coupling grating 3 is a diffraction grating or a holographic grating. When the coupling grating 3 is a diffraction grating, it can be a rectangular grating, a blazed grating, a tilted grating, a sinusoidal grating, or a holographic grating, with a groove depth of 50–200 nm.

[0076] In a preferred embodiment, the coupling grating 3 is set as a regular rectangular grating, and the first reflection grating 4 is set as a tilted grating or a blazed grating. Since the presence of the first reflection grating 4 greatly improves the light energy utilization of the waveguide 1, the coupling grating 3 does not need to be set as a tilted grating with high diffraction efficiency (in conventional schemes, due to the low diffraction efficiency of regular rectangular gratings, tilted gratings are selected as coupling gratings, but the high diffraction efficiency of tilted gratings results in higher energy coupling from the field of view closer to the coupling region 2, while lower energy coupling from the field of view farther from the coupling region 2, resulting in uneven energy distribution throughout the visible area). This scheme improves the light energy utilization by setting the first reflection grating 4, while avoiding uneven coupling energy in different fields of view.

[0077] In this embodiment, the thickness of waveguide 1 is 0.3 to 2.5 mm, the material of waveguide 1 is an optical material that is transparent to visible light, and the refractive index of waveguide 1 is 1.4 to 2.2.

[0078] In this embodiment, the coupling grating 3 is a one-dimensional grating. As will be readily apparent to those skilled in the art, in other embodiments, the coupling grating 3 is a two-dimensional grating, which should also be within the scope of protection of this application, and is not specifically limited here. When the coupling grating 3 is a two-dimensional grating, it can be composed of two one-dimensional gratings respectively disposed on both sides of the waveguide plate 1 or composed of two one-dimensional gratings disposed on one side of the waveguide plate 1 superimposed.

[0079] Example 2

[0080] In this embodiment, as Figure 1As shown, the coupling region 2 includes a coupling grating 21, which is used to couple light into the waveguide sheet 1. The coupling grating 21 is a rectangular grating, a blazed grating, a tilted grating, a sinusoidal grating, or a holographic grating, with a period of 300-600 nm and a groove depth of 40-500 nm.

[0081] Furthermore, the coupling region 2 also includes a folding grating 22, which is used to diffuse and transmit the light coupled from the coupling grating 21 within the waveguide 1. Adding the folding grating 22 can further increase the light energy utilization rate. Even further, the folding grating 22 is a rectangular grating, a blazed grating, a tilted grating, a sinusoidal grating, or a holographic grating, with a period of 300–600 nm and a groove depth of 40–500 nm.

[0082] Figure 5 for Figure 1 The diagram shows a waveguide assembly with a grating vector.

[0083] In this embodiment, as Figure 5 As shown, the coupling grating 21 has a grating vector G0a, and the turning grating 22 has a grating vector G0b. The vector sum of the coupling grating 21 and the turning grating 22 is equal to the grating vector G0 of the coupling region 2, i.e., G0a + G0b = G0. Meanwhile, the groove lines of the first reflection grating 4 and the coupling grating 3 are kept parallel, so that the uncoupled ray B is reflected back to the coupling grating 3 by the first reflection grating 4. When the period of the first reflection grating 4 is the same as the period of the coupling grating 3, the diffraction efficiency of the second-order diffracted light in its diffraction order is set to the maximum; or when the period of the first reflection grating 4 is half the period of the coupling grating 3, the diffraction efficiency of the first-order diffracted light in its diffraction order is set to the maximum. This makes the grating vector corresponding to the second-order diffracted light when the light ray B is diffracted at the first reflection grating 4 twice the size of the vector of the coupling grating 3, thus making the grating vector G0+G1+G2=0, and finally making the light ray C coupled out, thereby improving the light energy utilization rate, and the presence of the light ray C increases the exit pupil density. Furthermore, since the energy of light gradually decreases as it propagates in the waveguide, the uncoupled light rays are reflected back to the coupling grating 3 and partially diffracted out. The energy of this part of the light rays also gradually decreases during propagation, and its propagation direction is exactly opposite to that of light ray A in the waveguide 1. This compensates for the energy reduction of light ray A during its propagation in the waveguide 1, and improves the brightness uniformity of the coupled light rays in the entire visible area of ​​the waveguide.

[0084] In this embodiment, the coupling-in region 2 and the coupling-out grating 3 are located on the same surface of the waveguide plate 1. In other embodiments, the coupling-in region 2 and the coupling-out grating 3 are located on two opposite surfaces of the waveguide plate 1, which is not specifically limited here.

[0085] In this embodiment, the coupling grating 3 is a one-dimensional grating. As will be readily apparent to those skilled in the art, in other embodiments, the coupling grating 3 is a two-dimensional grating, which should also be within the scope of protection of this application, and is not specifically limited here. When the coupling grating 3 is a two-dimensional grating, it can be composed of two one-dimensional gratings respectively disposed on both sides of the waveguide plate 1 or composed of two one-dimensional gratings disposed on one side of the waveguide plate 1 superimposed.

[0086] In this embodiment, the coupling grating 3 is a rectangular grating, a blazed grating, a tilted grating, a sinusoidal grating, or a holographic grating, and the groove depth is 50-200 nm.

[0087] Example 3

[0088] Figure 6 This is a schematic diagram of the structure of a waveguide component provided in an embodiment of this application.

[0089] like Figure 6 As shown, in this embodiment, the first reflection grating 4 includes a first reflection grating 41 and a second reflection grating 42 that are set separately, and the sum of the grating vectors of the first reflection grating 41 and the second reflection grating 42 is G2.

[0090] In this embodiment, the coupling region 2 includes a coupling grating 21 and a turning grating 22.

[0091] The coupling grating 21 has a grating vector G0a, and the folding grating 22 has a grating vector G0b, such that G0a + G0b = G0.

[0092] The grating vector of the coupled grating 3 is G1.

[0093] Since the groove lines of the first reflection grating 41 and the second reflection grating 42 are parallel to the groove lines of the coupling grating 3, and the periods of the first reflection grating 41 and the second reflection grating 42 are the same as the period of the coupling grating 3, the diffraction efficiency of the second-order diffracted light is set to the maximum in its diffraction order; or the period of the first reflection grating 41 and the second reflection grating 42 is half the period of the coupling grating 3, and the diffraction efficiency of the first-order diffracted light is set to the maximum in its diffraction order, so that G0+G1+G2=0, and finally the light C is coupled out, thereby improving the light energy utilization, exit pupil density and brightness uniformity.

[0094] The waveguide assembly provided in this embodiment sets the first reflection grating 4 as two separate reflection gratings, which can reflect light from multiple directions, avoid omissions, and further improve light energy utilization, increase exit pupil density, and increase brightness uniformity.

[0095] In this embodiment, the coupling grating 3 is a one-dimensional grating. As will be readily apparent to those skilled in the art, in other embodiments, the coupling grating 3 is a two-dimensional grating, which should also be within the scope of protection of this application, and is not specifically limited here. When the coupling grating 3 is a two-dimensional grating, it can be composed of two one-dimensional gratings respectively disposed on both sides of the waveguide plate 1 or composed of two one-dimensional gratings disposed on one side of the waveguide plate 1 superimposed.

[0096] In this embodiment, the coupling grating 3 is a rectangular grating, a blazed grating, a tilted grating, a sinusoidal grating, or a holographic grating, and the groove depth is 50-200 nm.

[0097] In this embodiment, the thickness of waveguide 1 is 0.3 to 2.5 mm, the material of waveguide 1 is an optical material that is transparent to visible light, and the refractive index of waveguide 1 is 1.4 to 2.2.

[0098] In other embodiments, the coupling region 2 may have only the coupling grating 21 and no turning grating 22.

[0099] Example 4

[0100] Figure 7 This is a schematic diagram of the structure of a waveguide component provided in an embodiment of this application.

[0101] like Figure 7 As shown, the waveguide assembly provided in this embodiment also includes a second reflection grating 5, which is disposed on the same surface of the waveguide sheet 1 as the first reflection grating 4.

[0102] The second reflection grating 5 is positioned opposite to the first reflection grating 4 and is located on both sides of the coupling grating 3.

[0103] The groove line of the second reflection grating 5 is parallel to the groove line of the coupling grating 3. The period of the second reflection grating 5 is the same as the period of the coupling grating 3, and the diffraction efficiency of the second-order diffracted light in the diffraction order is set to the maximum. Alternatively, the period of the second reflection grating 5 is half the period of the coupling grating 3, and the diffraction efficiency of the first-order diffracted light in the diffraction order is set to the maximum.

[0104] The light rays that are not coupled out after being reflected by the first reflection grating 4 are transmitted to the second reflection grating 5, and are reflected back to the coupling grating 3 by the second reflection grating 5 and then coupled out again.

[0105] In this embodiment, the coupling region 2 includes a coupling grating 21 and a turning grating 22.

[0106] The sum of the grating vectors of the coupling grating 21 and the deflection grating 22 is equal to G0 as described in the previous embodiment. The first reflection grating 4 has a grating vector G1, and the sum of the grating vectors of the coupling grating 3 and the second reflection grating 5 is G2. Due to the groove line arrangement, period arrangement, and diffraction order arrangement of the first reflection grating 4 and the second reflection grating 5, G0 + G1 + G2 = 0, which ultimately ensures that light is coupled out after reflection by the first reflection grating 4 or after reflection by the second reflection grating 5, thereby improving the light energy utilization rate, exit pupil density, and brightness uniformity.

[0107] The waveguide assembly provided in this embodiment has a second reflection grating 5 on the waveguide sheet 1, and the second reflection grating 5 and the first reflection grating 4 are located on the same side of the waveguide sheet 1. The groove line of the second reflection grating 5 is parallel to the groove line of the coupling grating 3. The period of the second reflection grating 5 is the same as the period of the coupling grating 3, and the diffraction efficiency of the second-order diffracted light in the diffraction order is set to the maximum. Alternatively, the period of the second reflection grating 5 is half the period of the coupling grating 3, and the diffraction efficiency of the first-order diffracted light in the diffraction order is set to the maximum. This allows the light that is not coupled out after passing through the coupling grating 3 to be reflected back to the coupling grating 3 by the first reflection grating 41. The light that is still not coupled out is then reflected back to the coupling grating 3 by the second reflection grating 5, thereby further improving the light energy utilization rate, increasing the exit pupil density, and improving the brightness uniformity.

[0108] In this embodiment, the second reflection grating 5 is a sinusoidal grating, a rectangular grating, a blazed grating, or a tilted grating tilted towards the coupling grating 3. Preferably, the second reflection grating 5 is a tilted grating, in which case the diffraction efficiency is high (exceeding 80%). Furthermore, the second reflection grating 5 is tilted towards the coupling grating 3, further improving the reflection efficiency of the second reflection grating 5.

[0109] In this embodiment, the coupling grating 3 is a one-dimensional grating. As will be readily apparent to those skilled in the art, in other embodiments, the coupling grating 3 is a two-dimensional grating, which should also be within the scope of protection of this application, and is not specifically limited here. When the coupling grating 3 is a two-dimensional grating, it can be composed of two one-dimensional gratings respectively disposed on both sides of the waveguide plate 1 or composed of two one-dimensional gratings disposed on one side of the waveguide plate 1 superimposed.

[0110] In this embodiment, the coupling grating 3 is a rectangular grating, a blazed grating, a tilted grating, a sinusoidal grating, or a holographic grating, and the groove depth is 50-200 nm.

[0111] In this embodiment, the thickness of waveguide 1 is 0.3 to 2.5 mm, the material of waveguide 1 is an optical material that is transparent to visible light, and the refractive index of waveguide 1 is 1.4 to 2.2.

[0112] In other embodiments, the coupling region 2 may have only the coupling grating 21 and no turning grating 22.

[0113] Example 5

[0114] Figure 8 This is a schematic diagram of the structure of a waveguide component provided in an embodiment of this application.

[0115] In this embodiment, as Figure 8 As shown, the first reflection grating 4 includes a first reflection grating 41 and a second reflection grating 42 arranged in phase separation, and the second reflection grating 5 includes a third reflection grating 51 and a fourth reflection grating 52 arranged in phase separation. The first reflection grating 41 and the third reflection grating 51 are arranged opposite to each other, and the second reflection grating 42 and the fourth reflection grating 52 are arranged opposite to each other. That is, the first reflection grating 41, the second reflection grating 42, the third reflection grating 51 and the fourth reflection grating 52 are arranged sequentially around the coupling-in region 2 and the coupling-out grating 3.

[0116] The periods of the first and second reflection gratings 41 and 42 are equal to the period of the coupling grating 3 in the vertical direction, and their second-order diffraction efficiency is set to the maximum, which can reach over 80% after optimization. The periods of the third and fourth reflection gratings 51 and 52 are equal to the period of the coupling grating 3 in the horizontal direction, and their second-order diffraction efficiency is set to the maximum, which can reach over 80% after optimization. This allows uncoupled light rays to propagate back and forth in the corresponding reflection gratings (41, 51 or 42, 52), improving the light energy utilization, exit pupil density, and brightness uniformity of the waveguide 1. It can be understood that the periods of the first and second reflection gratings 41 and 42, and the periods of the third and fourth reflection gratings 51 and 52 can also be set to half the period of the coupling grating 3, and the diffraction efficiency of the first-order diffraction light in their corresponding diffraction orders is set to the maximum.

[0117] The waveguide assembly provided in this embodiment sets the first reflection grating 4 as two separate reflection gratings (41, 42) and the second reflection grating 5 as two separate reflection gratings (51, 52), thereby enabling light to be reflected back from multiple directions and to be transmitted back and forth between multiple reflection gratings (between 41 and 51 or between 42 and 52), thereby improving light energy utilization, exit pupil density and brightness uniformity.

[0118] In this embodiment, the coupling grating 3 is a two-dimensional grating. Specifically, the coupling grating 3 can be composed of two one-dimensional gratings respectively disposed on both sides of the waveguide plate 1, or it can be composed of two one-dimensional gratings superimposed on one side of the waveguide plate 1. In other embodiments, the coupling grating 3 can also be a one-dimensional grating, which is not specifically limited here.

[0119] In this embodiment, the coupling region 2 includes only the coupling grating 21. In other embodiments, the coupling region may also include the coupling grating 21 and the turning grating 22.

[0120] In this embodiment, the coupling grating 3 is a rectangular grating, a blazed grating, a tilted grating, a sinusoidal grating, or a holographic grating, and the groove depth is 50-200 nm.

[0121] Example 6

[0122] Figure 9 for Figure 8 A side view of a portion of the waveguide assembly shown.

[0123] In this embodiment, as Figure 9 As shown, the coupling grating 3 is a two-dimensional grating, and is composed of two one-dimensional gratings (31, 32) respectively disposed on the two surfaces of the waveguide sheet 1.

[0124] Light rays are coupled into waveguide 1 through coupling region 2. Light rays that are not coupled out by two-dimensional coupling gratings 3 (31, 32) are reflected by first reflection grating 4 (or 41) and then coupled out by two-dimensional coupling gratings 3 (31, 32).

[0125] Figure 10 for Figure 8 A raster vector diagram of the waveguide assembly shown.

[0126] The coupling region 2 has a grating vector G0, the one-dimensional coupling grating 31 has a grating vector G1, the one-dimensional coupling grating 32 has a grating vector G2, and the first reflection grating 4 (42) has a grating vector G3. Due to the parallelism of the groove lines and the setting of the period and diffraction order, G0+G1+G2+G3=0, so that the light rays that are not coupled out are coupled out by the two-dimensional coupling grating 3 (31, 32) after being reflected by the first reflection grating 4 (42), which improves the light energy utilization rate, increases the exit pupil density, and increases the brightness uniformity.

[0127] Figure 11 for Figure 8 A raster vector diagram of the waveguide assembly shown.

[0128] like Figure 11As shown, the coupling region 2 has a grating vector G0, the one-dimensional coupling grating 31 has a grating vector G1, the one-dimensional coupling grating 32 has a grating vector G2, the first reflection grating 4 (42) has a grating vector G3, and the second reflection grating 5 (52) has a grating vector G4. Due to the parallelism of the groove lines and the setting of the period and diffraction order, G0+G1+G2+G3+G4=0, so that the light that has not been coupled out after being reflected by the first reflection grating 4 (42) is transmitted to the second reflection grating 5 (52) and reflected back to the coupling grating 3 (31, 32) by the second reflection grating 5 (52), thereby improving the light energy utilization rate, increasing the exit pupil density, and increasing the brightness uniformity.

[0129] Figure 12 for Figure 8 A raster vector diagram of the waveguide assembly shown.

[0130] like Figure 12 As shown, the coupling region 2 has a grating vector G0, the one-dimensional coupling grating 31 has a grating vector G1, the first reflection grating 4 (41) has a grating vector G2, and the one-dimensional coupling grating 32 has a grating vector G3. Due to the parallelism of the groove lines and the setting of the period and diffraction order, G0+G1+G2+G3=0, so that the light that was diffracted by the one-dimensional coupling grating 31 but not coupled out by the one-dimensional coupling grating 32 is reflected by the first reflection grating 4 (41) and then coupled out by the coupling grating 31, which improves the light energy utilization, increases the exit pupil density, and increases the brightness uniformity.

[0131] Figure 13 for Figure 8 A raster vector diagram of the waveguide assembly shown.

[0132] like Figure 13 As shown, the coupling region 2 has a grating vector G0, the one-dimensional coupling grating 32 has a grating vector G1, the second reflection grating 5 (51) has a grating vector G2, and the one-dimensional coupling grating 32 has a grating vector G3. Due to the parallelism of the groove lines and the setting of the period and diffraction order, G0+G1+G2+G3=0, so that the light that was diffracted by the one-dimensional coupling grating 32 but not coupled out by the one-dimensional coupling grating 31 is reflected by the second reflection grating 5 (51) and then coupled out by the coupling grating 32, which improves the light energy utilization rate, increases the exit pupil density, and increases the brightness uniformity.

[0133] Furthermore, the included angle between the two one-dimensional gratings of the coupling grating 3 is 50-70 degrees.

[0134] In this embodiment, the coupling grating 3 is a rectangular grating, a blazed grating, a tilted grating, a sinusoidal grating, or a holographic grating, and the groove depth is 50-200 nm.

[0135] In other embodiments, the coupling grating 3 is composed of two one-dimensional gratings superimposed on the same surface of the waveguide sheet 1.

[0136] In this embodiment, the thickness of waveguide 1 is 0.3 to 2.5 mm, the material of waveguide 1 is an optical material that is transparent to visible light, and the refractive index of waveguide 1 is 1.4 to 2.2.

[0137] Example 7

[0138] Figure 14 This is a schematic diagram of the structure of a near-eye display device provided in an embodiment of this application.

[0139] like Figure 14 As shown, one embodiment of this application also provides a near-eye display device, including a projection optical engine 6 and a waveguide assembly, wherein the waveguide assembly is the waveguide assembly described in any of the above embodiments. In this embodiment, the waveguide assembly includes:

[0140] Waveguide 1;

[0141] The coupling region 2 is disposed on a surface of the waveguide 1. The coupling region 2 is used to couple light into the waveguide 1 and to diffuse and transmit the light within the waveguide 1.

[0142] A coupling grating 3 is disposed on one surface of the waveguide 1. The coupling grating 3 is used to couple the light rays coupled in from the coupling region 2 out of the waveguide 1; and

[0143] The first reflection grating 4 is disposed on the same surface of the waveguide plate 1 as the coupling grating 3 and is located at the end of the coupling grating 3 along the light transmission direction. The groove lines of the first reflection grating 4 and the coupling grating 3 are parallel. The first reflection grating 4 and the coupling grating 3 have the same period and the diffraction efficiency of the second-order diffracted light in the diffraction order is set to the maximum. Alternatively, the first reflection grating 4 is half the period of the coupling grating 3 and the diffraction efficiency of the first-order diffracted light in the diffraction order is set to the maximum. The first reflection grating 4 is used to reflect the light that has passed through the coupling grating 3 but has not been coupled back to the coupling grating 3 and then coupled out again.

[0144] The working principle of the waveguide component provided in this embodiment is as follows:

[0145] The light emitted by the projector 6 is coupled into the waveguide 1 through the coupling region 2, and then diffuses and propagates within the waveguide 1 to the coupling grating 3. The coupling grating 3 couples the light ray A out of the waveguide 1, making it visible to the human eye and thus forming the visible area. The light ray B that is not coupled out continues to propagate to the first reflection grating 4, which reflects the light ray B back to the coupling grating 3, and then couples it out again as light ray C. Light ray C remains parallel to light ray A.

[0146] The near-eye display device provided in this application includes a projection optical engine 6 and a waveguide assembly. The waveguide assembly has a first reflection grating 4 disposed on one side surface of the waveguide sheet 1, with the first reflection grating 4 parallel to the groove lines of the coupling grating 3. The first reflection grating 4 and the coupling grating 3 have the same period, and the diffraction efficiency of the second-order diffracted light in the diffraction order is set to maximum; or the first reflection grating 4 has half the period of the coupling grating 3, and the diffraction efficiency of the first-order diffracted light in the diffraction order is set to maximum. This allows light rays that have passed through the coupling grating 3 but not coupled out to be returned to the coupling grating 3 by the first reflection grating 4, thus achieving coupling out. This improves the overall light energy utilization of the waveguide assembly and increases the overall exit pupil density of the waveguide assembly. Furthermore, since the light rays returned and re-coupled after passing through the first reflection grating 4 supplement the previously coupled light rays, the brightness uniformity of the coupled light rays within the overall visible area of ​​the waveguide sheet 1 is improved. Moreover, according to the optical design of this invention, only the first reflection grating 4 needs to be disposed on one side surface of the waveguide sheet 1, simplifying the manufacturing process and facilitating production. Moreover, the waveguide component provided in this embodiment allows light rays that are not coupled out by the first coupling grating 3 to return to the coupling grating 3 only by passing through a first reflection grating 4, resulting in higher light energy utilization.

[0147] Example 8

[0148] Figure 15 This is a schematic diagram of the structure of a near-eye display device provided in an embodiment of this application.

[0149] In this embodiment, the waveguide assembly further includes a second reflection grating 5, which is disposed on the same surface of the waveguide sheet 1 as the first reflection grating 4.

[0150] The second reflection grating 5 is positioned opposite to the first reflection grating 4 and is located on both sides of the coupling grating 3.

[0151] The groove line of the second reflection grating 5 is parallel to the groove line of the coupling grating 3. The period of the second reflection grating 5 is the same as the period of the coupling grating 3, and the diffraction efficiency of the second-order diffracted light in the diffraction order is set to the maximum. Alternatively, the period of the second reflection grating 5 is half the period of the coupling grating 3, and the diffraction efficiency of the first-order diffracted light in the diffraction order is set to the maximum.

[0152] The light rays that are not coupled out after being reflected by the first reflection grating 4 are transmitted to the second reflection grating 5, and are reflected back to the coupling grating 3 by the second reflection grating 5 and then coupled out again.

[0153] The working principle of the waveguide component provided in this embodiment is as follows:

[0154] The light emitted by the projector 6 is coupled into the waveguide 1 through the coupling region 2 and diffuses within the waveguide 1 to the coupling grating 3. The coupling grating 3 couples light ray A out of the waveguide 1, thus forming the visible area. Light ray B, which is not coupled out, continues to propagate to the first reflection grating 4. The first reflection grating 4 reflects light ray B back to the coupling grating 3, and then couples it out again, becoming light ray C, which remains parallel to light ray A. Some light ray D remains uncoupled and continues to propagate to the second reflection grating 5, where it is reflected back to the coupling grating 3, which then couples it out.

[0155] The near-eye display device provided in this embodiment has a second reflection grating 5 set on the waveguide plate 1 in the waveguide assembly. The second reflection grating 5 and the first reflection grating 4 are located on the same side of the waveguide plate 1, and the groove line of the second reflection grating 5 is parallel to the groove line of the coupling grating 3. The period of the second reflection grating 5 is the same as the period of the coupling grating 3, and the diffraction efficiency of the second-order diffracted light in the diffraction order is set to the maximum. Alternatively, the period of the second reflection grating 5 is half the period of the coupling grating 3, and the diffraction efficiency of the first-order diffracted light in the diffraction order is set to the maximum. This allows the light that is not coupled out after passing through the coupling grating 3 to be reflected back to the coupling grating 3 by the first reflection grating 41. The light that is still not coupled out is then reflected back to the coupling grating 3 by the second reflection grating 5, thereby further improving the light energy utilization, increasing the exit pupil density, and improving the brightness uniformity.

[0156] In the description of this invention, it should be noted that the terms "upper" and "lower," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0157] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linkage" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0158] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A waveguide assembly, characterized in that, include: Waveguide sheet (1); A coupling region (2) is provided on one surface of the waveguide (1). The coupling region (2) is used to couple light into the waveguide (1) and allow the light to diffuse and propagate within the waveguide (1). A coupling grating (3) is disposed on one surface of the waveguide plate (1). The coupling grating (3) is used to couple light rays coupled from the coupling region (2) out of the waveguide plate (1). The first reflection grating (4) is disposed on the same surface of the waveguide plate (1) as the coupling grating (3) and located at the end of the coupling grating (3) along the light transmission direction. The first reflection grating (4) is parallel to the groove line of the coupling grating (3). The coupling region (2) has a grating vector G0, the coupling grating (3) has a grating vector G1, and the first reflection grating (4) has a grating vector G2. The grating vectors G0 + G1 + G2 = 0. The first reflection grating (4) reflects the light that has passed through the coupling grating (3) but has not been coupled back to the coupling grating (3) and is then coupled out. A second reflection grating (5) is provided on the same surface of the waveguide plate (1) as the first reflection grating (4). The second reflection grating (5) and the first reflection grating (4) are arranged opposite to each other and located on both sides of the coupling grating (3). The groove line of the second reflection grating (5) is parallel to the groove line of the coupling grating (3). The period of the second reflection grating (5) is the same as the period of the coupling grating (3) and the diffraction efficiency of the second-order diffracted light in the diffraction order is set to the maximum. Alternatively, the period of the second reflection grating (5) is half the period of the coupling grating (3) and the diffraction efficiency of the first-order diffracted light in the diffraction order is set to the maximum. The light rays that are not coupled out after being reflected by the first reflection grating (4) are transmitted to the second reflection grating (5) and reflected back to the coupling grating (3) by the second reflection grating (5).

2. The waveguide assembly according to claim 1, characterized in that, The first reflection grating (4) includes a first reflection grating (41) and a second reflection grating (42) that are set separately.

3. The waveguide assembly according to claim 1 or 2, characterized in that, The first reflection grating (4) is a sinusoidal grating, a rectangular grating, a blazed grating, or a tilted grating tilted in the direction of the coupling grating (3).

4. The waveguide assembly according to claim 1, characterized in that, The first reflection grating (4) includes a first reflection grating (41) and a second reflection grating (42) arranged in phase. The second reflection grating (5) includes a third reflection grating (51) and a fourth reflection grating (52) arranged in phase. The first reflection grating (41) and the third reflection grating (51) are arranged opposite to each other, and the second reflection grating (42) and the fourth reflection grating (52) are arranged opposite to each other.

5. The waveguide assembly according to claim 1 or 2, characterized in that, The coupling grating (3) is a one-dimensional grating.

6. The waveguide assembly according to claim 1 or 2, characterized in that, The coupling grating (3) is composed of two one-dimensional gratings respectively disposed on two surfaces of the waveguide plate (1) or is composed of two one-dimensional gratings superimposed on the same surface of the waveguide plate (1).

7. The waveguide assembly according to claim 6, characterized in that, The included angle between the two one-dimensional gratings of the coupled grating (3) is 50-70 degrees.

8. The waveguide assembly according to claim 1 or 2, characterized in that, The coupled grating (3) is a rectangular grating, a blazed grating, a tilted grating, a sinusoidal grating, or a holographic grating, with a groove depth of 50 to 200 nm.

9. The waveguide assembly according to claim 1 or 2, characterized in that, The first reflection grating (4) is adjacent to the coupling grating (3).

10. The waveguide assembly according to claim 1 or 2, characterized in that, The width of the first reflection grating (4) is greater than 3 mm.

11. The waveguide assembly according to claim 1 or 2, characterized in that, The coupling grating (3) is a rectangular grating, and the first reflection grating (4) and / or the second reflection grating (5) are tilted gratings or blazed gratings.

12. The waveguide assembly according to claim 1 or 2, characterized in that, The coupling region (2) includes a coupling grating (21) for coupling light into the waveguide sheet (1).

13. The waveguide assembly according to claim 12, characterized in that, The coupled grating (21) is a rectangular grating, a blazed grating, a tilted grating, a sinusoidal grating or a holographic grating, with a period of 300-600 nm and a groove depth of 40-500 nm.

14. The waveguide assembly according to claim 12, characterized in that, The coupling region (2) further includes a folding grating (22) for diffusing and transmitting light coupled from the coupling grating (21) within the waveguide sheet (1).

15. The waveguide assembly according to claim 14, characterized in that, The transition grating (22) is a rectangular grating, a blazed grating, a tilted grating, a sinusoidal grating, or a holographic grating, with a period of 300-600 nm and a groove depth of 40-500 nm.

16. The waveguide assembly according to claim 1 or 2, characterized in that, The coupling region (2) and the coupling grating (3) are located on the same surface of the waveguide plate (1) or on two opposite surfaces of the waveguide plate (1).

17. The waveguide assembly according to claim 1 or 2, characterized in that, The waveguide (1) has a thickness of 0.3 to 2.5 mm, and the waveguide (1) is made of an optical material that is transparent to visible light. The refractive index of the waveguide (1) is 1.4 to 2.2.

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