CN117388975A - Waveguide sheet and display device - Google Patents
Waveguide sheet and display device Download PDFInfo
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- CN117388975A CN117388975A CN202311176392.2A CN202311176392A CN117388975A CN 117388975 A CN117388975 A CN 117388975A CN 202311176392 A CN202311176392 A CN 202311176392A CN 117388975 A CN117388975 A CN 117388975A
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- 230000008878 coupling Effects 0.000 claims abstract description 11
- 238000010168 coupling process Methods 0.000 claims abstract description 11
- 238000005859 coupling reaction Methods 0.000 claims abstract description 11
- 230000001902 propagating effect Effects 0.000 claims abstract description 10
- 210000001747 pupil Anatomy 0.000 claims description 15
- 230000000737 periodic effect Effects 0.000 claims description 9
- 230000000694 effects Effects 0.000 abstract description 16
- 230000003313 weakening effect Effects 0.000 abstract description 6
- 239000013598 vector Substances 0.000 description 65
- 238000010586 diagram Methods 0.000 description 21
- 230000000875 corresponding effect Effects 0.000 description 19
- 238000000034 method Methods 0.000 description 12
- 230000003287 optical effect Effects 0.000 description 6
- 230000005540 biological transmission Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000000644 propagated effect Effects 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 230000003190 augmentative effect Effects 0.000 description 1
- 230000002596 correlated effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000002834 transmittance Methods 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Classifications
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0033—Means for improving the coupling-out of light from the light guide
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/01—Head-up displays
- G02B27/0101—Head-up displays characterised by optical features
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/18—Diffraction gratings
- G02B5/1866—Transmission gratings characterised by their structure, e.g. step profile, contours of substrate or grooves, pitch variations, materials
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0033—Means for improving the coupling-out of light from the light guide
- G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
- G02B6/122—Basic optical elements, e.g. light-guiding paths
- G02B6/124—Geodesic lenses or integrated gratings
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Diffracting Gratings Or Hologram Optical Elements (AREA)
Abstract
The application provides a waveguide sheet and a display device. The waveguide sheet comprises a light coupling-in area and a light coupling-out area, wherein the light coupling-in area and the light coupling-out area are respectively provided with a diffraction microstructure device, the diffraction microstructure devices arranged in the light coupling-out area are two-dimensional gratings, and the grating period of the two-dimensional gratings in any period direction is more than or equal to 200 nanometers and less than or equal to 350 nanometers; the diffraction microstructure device arranged in the light coupling-in area is used for coupling light into the waveguide plate; the two-dimensional grating is used for diffracting first light rays propagating in the waveguide sheet to obtain first diffracted light rays, and is further used for diffracting second light rays irradiated to the two-dimensional grating from the outside of the waveguide sheet to obtain second diffracted light rays, so that the second diffracted light rays are emitted to the outside of the waveguide sheet at a first preset emergent angle, the effect of weakening rainbow lines is reduced or the generation of rainbow lines is avoided, the influence of the rainbow lines on a user is reduced, and the waveguide sheet can normally display images and improve the use experience of the user.
Description
Technical Field
The application relates to the technical field of optical waveguides, in particular to a waveguide sheet and display equipment.
Background
The waveguide sheet, which is a main component of an AR (augmented reality) display device, has a light signal transmission function and good light transmittance, so that a user can view a real environment while viewing an image displayed on the waveguide sheet. One-dimensional or two-dimensional gratings are usually arranged in the waveguide sheet to realize that light rays propagating in the waveguide sheet are coupled out to human eyes, the gratings have obvious dispersion effect, and when complex-color light generated by lamplight in an external environment irradiates an area of the waveguide sheet where the gratings are positioned, part of diffracted light can be separated in space according to wavelengths and folded back into human eyes, so that a color strip-shaped image is formed in the field of view of the human, and the rainbow effect of the optical waveguide is generated. The existence of rainbow lines can seriously interfere with the vision of a user, and influence the normal display of a waveguide sheet and the use experience of the user on an AR display device.
Disclosure of Invention
The application provides a waveguide piece and display device, aim at weakening the luminous intensity of rainbow line to reduce the influence of rainbow line to the user, make the waveguide piece can normally show the image and promote user AR display device's use experience.
In a first aspect, the present application provides a waveguide sheet, including a light coupling-in region and a light coupling-out region, where both the light coupling-in region and the light coupling-out region are provided with diffraction microstructure devices, the diffraction microstructure devices provided in the light coupling-out region are two-dimensional gratings, and a grating period of the two-dimensional gratings in any period direction is greater than or equal to 200 nm and less than or equal to 350 nm; the diffraction microstructure device arranged in the light coupling-in area is used for coupling light into the waveguide plate; the two-dimensional grating is used for diffracting first light rays propagating in the waveguide sheet to obtain first diffracted light rays, and diffracting second light rays irradiated to the two-dimensional grating from the outside of the waveguide sheet to obtain second diffracted light rays, wherein the second diffracted light rays are emitted to the outside of the waveguide sheet at a first preset emergent angle.
In an embodiment, an included angle between a first periodic direction of the two-dimensional grating and a second periodic direction of the two-dimensional grating is smaller than 90 °, the two-dimensional grating diffracts a second light beam irradiated to the two-dimensional grating from the outside of the waveguide sheet to obtain a second diffracted light beam and a third diffracted light beam, and the third diffracted light beam is emitted to the outside of the waveguide sheet at a second preset emission angle.
In an embodiment, the grating period of the two-dimensional grating in the first period direction and the grating period in the second period direction are both greater than or equal to 200 nm and less than or equal to 350 nm.
In one embodiment, the diffraction microstructure device disposed in the light coupling region is a grating, and a grating period of the grating is greater than or equal to 250 nm and less than 450 nm.
In an embodiment, an included angle between a periodic direction of the grating disposed in the light coupling-in area and the predetermined direction is smaller than 45 °.
In an embodiment, the diffraction microstructure device disposed in the light coupling-out area further includes a one-dimensional grating, and the one-dimensional grating is disposed adjacent to the two-dimensional grating; the two-dimensional grating is also used for carrying out two-dimensional pupil expansion processing on the first light rays incident to the two-dimensional grating, and the one-dimensional grating is used for carrying out one-dimensional pupil expansion processing on the light rays subjected to the two-dimensional pupil expansion processing.
In an embodiment, the diffractive microstructure device provided with the light incoupling region and the light outcoupling region comprises at least one of a surface relief grating, a volume hologram grating, and a super-structured surface.
In an embodiment, a distance from a center point of the light coupling-in region to any boundary tangent line of the light coupling-out region along the predetermined direction is less than or equal to 5 mm.
In one embodiment, the waveguide sheet further includes a light turning region; the light turning region is adjacently arranged in the light coupling-in region and the light coupling-out region, and is used for transmitting the first light obtained by coupling in from the light coupling-in region to the light coupling-out region.
In a second aspect, the present application further provides a display device, where the display device includes a light engine and a waveguide sheet according to any one of the embodiments provided in the first aspect, and a light coupling-in area in the waveguide sheet is configured to couple light emitted by the light engine into the waveguide sheet, and couple light propagating in the waveguide sheet out to a human eye through the light coupling-out area in the waveguide sheet.
The utility model provides a waveguide piece and display device, through set up two-dimensional grating in the light coupling-out region of waveguide piece, and the grating period of two-dimensional grating that sets up on the periodic direction is greater than or equal to 200 nanometers and less than or equal to 350 nanometers, make two-dimensional grating even can shine the second light to two-dimensional grating from waveguide piece outside and carry out the diffraction and obtain second diffraction light, at least part second diffraction light is with first default exit angle outgoing to waveguide piece's outside, thereby reduce the second diffraction light that gets into light coupling-out region or avoid second diffraction light to get into the people's eye, realize weakening rainbow line effect or avoid the production of rainbow line effect, thereby reduce the influence of rainbow line to the user, make the waveguide piece can normally show the image and promote the user to the use experience of the display device who is equipped with this waveguide piece.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a wave vector diagram of the generation principle of the rainbow ripple effect of a waveguide sheet in the prior art;
FIG. 2 is a schematic structural diagram of a waveguide sheet according to an embodiment of the present disclosure;
FIG. 3 is a schematic diagram of a grating structure according to an embodiment of the present disclosure;
FIG. 4a is a wave vector diagram according to an embodiment of the present application;
FIG. 4b is a wave vector diagram according to another embodiment of the present application;
FIG. 5 is a wave vector diagram provided in another embodiment of the present application;
FIG. 6 is a schematic diagram of a light propagation path according to an embodiment of the present disclosure;
FIG. 7 is a wave vector diagram according to yet another embodiment of the present application;
FIG. 8 is a schematic view of a light propagation path according to another embodiment of the present disclosure;
FIG. 9 is a schematic view of a waveguide chip according to an embodiment of the present disclosure;
FIG. 10 is a schematic view of a light propagation path according to another embodiment of the present disclosure;
fig. 11 is a schematic structural diagram of a display device according to an embodiment of the present application.
Detailed Description
The following description of the embodiments of the present application 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, of the embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.
The flow diagrams depicted in the figures are merely illustrative and not necessarily all of the elements and operations/steps are included or performed in the order described. For example, some operations/steps may be further divided, combined, or partially combined, so that the order of actual execution may be changed according to actual situations.
Some embodiments of the present application are described in detail below with reference to the accompanying drawings. The following embodiments and features of the embodiments may be combined with each other without conflict.
Referring to fig. 1, fig. 1 is a wave vector diagram of the generation principle of the rainbow ripple effect of the waveguide sheet in the prior art.
As shown in fig. 1, the region C1 is used to indicate the range of light that can be coupled out of the grating of the waveguide plate to the human eye, it can be understood that the light indicated in the region C1 can be perceived by the user, the light indicated outside the region C1 cannot enter the human eye, the region C21 is used to indicate the light region corresponding to the refractive index of air, the region C3 is used to indicate the light region corresponding to the refractive index of the waveguide, it is noted that the light indicated outside the region C1 in the region C21 is transmitted and reflected in the waveguide plate, the light indicated outside the region C21 and inside the region C3 is transmitted by total reflection in the waveguide plate, and the light indicated outside the region C3 is not actually present. K is used for indicating a grating vector (only the first order diffraction light in the direction of one grating vector is taken as an example in the figure), as shown in the figure, after all the angle light rays incident on the grating surface are diffracted by the grating, the state of the diffracted light rays can be shown as a C22 area, namely, the incident light rays with partial angles can not have corresponding diffracted light rays, the diffracted light rays corresponding to the incident light rays with partial angles can be transmitted in a waveguide sheet in a total reflection way or a partial reflection way, and in fig. 1, the C22 area and the C1 area have intersection, namely, the diffracted light rays corresponding to the incident light rays with partial angles can be seen by human eyes, namely, a rainbow-mark effect appears. It can be understood that in this state, if the rainbow effect needs to be solved, the grating vector K may be lengthened, so that the C22 area and the C1 area do not intersect, but if the length of the grating vector K is simply increased, the angle transmission of the light input by the optical machine is not complete, and the image displayed by the waveguide sheet is missing.
Referring to fig. 2, fig. 2 is a schematic structural diagram of a waveguide sheet according to an embodiment of the present application.
As shown in fig. 2, the waveguide sheet includes a light coupling-in region a and a light coupling-out region B, where the light coupling-in region a and the light coupling-out region B are both provided with diffraction microstructure devices, the diffraction microstructure devices provided in the light coupling-out region B are two-dimensional gratings, and the grating period of the two-dimensional gratings in any period direction is greater than or equal to 200 nm and less than or equal to 350 nm.
The diffraction microstructure device arranged in the light coupling-in area A is used for coupling light into the waveguide sheet to obtain first light, the first light can propagate in the waveguide sheet, and when the first light is incident to the two-dimensional grating, the two-dimensional grating diffracts the first light to obtain first diffracted light. The two-dimensional grating diffracts the second light irradiated to the two-dimensional grating from the outside of the waveguide plate to obtain second diffracted light, and it can be understood that the second light irradiated to the two-dimensional grating from the outside of the waveguide plate is ambient light, namely light causing rainbow effect.
It should be understood that, in a specific implementation scenario, when a user wears a display device made of a waveguide sheet, light emitted from the waveguide sheet at certain angles is not observed by human eyes, that is, the light is located outside the field of view of the user, and the waveguide sheet provided by the application makes second diffracted light emitted from the first preset angle not visible by human eyes, so that the user cannot observe rainbow lines, and the influence of the rainbow lines on the user is avoided.
In other implementation processes, when the two-dimensional grating diffracts the second light, the second diffracted light emitted in different directions can be obtained, for example, part of the second diffracted light is emitted in a first preset emission angle, part of the second diffracted light is emitted in other angles, the light intensity of rainbow lines observed by human eyes is positively correlated with the light intensity of the second diffracted light entering human eyes, and as the grating period of the two-dimensional grating in any period direction is greater than or equal to 200 nanometers and less than or equal to 350 nanometers, the two-dimensional grating can emit the second diffracted light in at least one direction to the outside of the waveguide sheet in the first preset emission angle, so that the human eyes cannot observe the light intensity of the rainbow lines, and the purpose of weakening the light intensity of the rainbow lines is achieved.
In an embodiment, the grating period of the two-dimensional grating in the first period direction and the grating period in the second period direction are both greater than or equal to 200 nm and less than or equal to 350 nm.
It can be understood that when the grating period of the two-dimensional grating in the first period direction and the grating period of the two-dimensional grating in the second period direction are both greater than or equal to 200 nm and less than or equal to 350 nm, the second diffracted light in all the grating period directions can not be incident to human eyes when a user wears the display device made of the waveguide sheet, so that the purpose of avoiding rainbow lines is achieved.
Referring to fig. 3, fig. 3 is a schematic diagram of a grating structure according to an embodiment of the present application.
In an embodiment, an included angle between the first periodic direction of the two-dimensional grating and the second periodic direction of the two-dimensional grating is smaller than 90 °, the two-dimensional grating diffracts the second light irradiated to the two-dimensional grating from the outside of the waveguide sheet to obtain a second diffracted light and a third diffracted light, and the third diffracted light is emitted to the outside of the waveguide sheet at a second preset emission angle.
The second diffraction light and the third diffraction light can be used for indicating diffraction light of different secondary levels of the second light, and the second diffraction light and the third diffraction light are emitted at different angles under the action of the two-dimensional grating. Specifically, the third diffracted light emitted at the second preset emitting angle cannot be observed by human eyes, so that the effect of eliminating the rainbow effect is achieved.
It should be noted that, the line segments K1 and K2 in fig. 3 are used for indicating the first grating vectors in the two directions in the first period direction of the two-dimensional grating, the line segments K3 and K4 are used for indicating the second grating vectors in the two directions in the second period direction of the two-dimensional grating, and the second diffracted light corresponding to the second light is emitted to the outside of the waveguide sheet at the first preset angle through the action of the first grating vectors and the second grating vectors on the wave vectors of the second light. The direction of the grating vector is parallel to the direction of the grating period, the size of the grating vector (shown by the length in the figure) is the wavelength divided by the grating period, it should be understood that the size of the grating vector is inversely related to the period size of the grating period, so that when the period size of the grating period is smaller, at least part of the second diffracted light rays are emitted at a first preset angle under the action of the grating vector parallel to the direction of the grating period, thereby achieving the purpose of weakening the light intensity of the rainbow patterns, and it can be understood that if the two-dimensional grating meets 200 nm or more and 350 nm or less in both grating periods, all the second diffracted light rays are emitted at the first preset angle or the second preset angle, that is, the second diffracted light rays cannot be observed by human eyes, thereby achieving the effect of avoiding the generation of the rainbow patterns.
Referring to fig. 4a and fig. 4b in conjunction with fig. 3, fig. 4a is a wave vector diagram provided in an embodiment of the present application, and fig. 4b is a wave vector diagram provided in another embodiment of the present application.
In a specific implementation process, as shown in fig. 4a, after the light rays of all angles, of which the second light rays are incident on the surface of the two-dimensional grating, are diffracted by the two-dimensional grating, the second diffracted light rays are obtained, and the second diffracted light rays are emitted from the first grating vector (line segment K1, line segment K2) at a first preset angle, and the corresponding wave vector diagram is shown in fig. 4a, wherein the C22 area and the C23 area in fig. 4a are used for indicating the state of the second diffracted light rays, and therefore, under the condition that the grating vector is long enough, the C22 area, the C23 area and the C1 area do not have intersection, so that the second diffracted light rays are prevented from entering human eyes, and rainbow marks are prevented from being observed by human eyes. It should be understood that fig. 4b is used to indicate the state of the second diffracted light under the action of the second grating vector (line segment K3, line segment K4), and it can be seen that the C22 area and the C23 area still have no intersection with the C1 area in the case of fig. 4b, so that the rainbow pattern is avoided from being observed by human eyes.
As shown in fig. 4a and 4b, the C22 region and the C23 region have a partial region outside the C21 region and within the C3 region, that is, the diffracted light indicated by the partial region is totally reflected and propagated in the waveguide sheet, but the rainbow pattern is not observed by human eyes.
Referring to fig. 5 and fig. 6, fig. 5 is a wave vector diagram provided in another embodiment of the present application, and fig. 6 is a schematic diagram of a light propagation path provided in an embodiment of the present application.
In a specific implementation process, as shown in fig. 5, the light coupling-in area couples light into the waveguide sheet to obtain a first light, where a0 in fig. 5 is used to indicate a wave vector corresponding to the light coupled into the waveguide sheet, a1 is used to indicate a wave vector corresponding to the first light, it can be understood that the first light propagates by total reflection in the waveguide sheet, when the first light is incident on the two-dimensional grating, the two-dimensional grating diffracts the first light to obtain a first diffracted light, and in combination with fig. 5, it is described that under the action of the first grating vector (line segment K1, line segment K2) and the second grating vector (line segment K3, line segment K4), wave vectors (a 2, a3, a4, a 5) corresponding to the first diffracted light are obtained, where the wave vectors after the action of different grating vectors indicate different secondary diffracted lights, for example, the wave vector a2 is used to indicate first-order diffracted lights, it can be understood that the wave vector a2 is also used to indicate other secondary diffracted lights, and is not limited herein.
It should be noted that, under the action of the first grating vector and the second grating vector, the wave vector corresponding to the first diffracted light further includes a wave vector corresponding to a vector obtained by vector synthesis of the first grating vector and the second grating vector, for example, the wave vector a0, and since the propagation angle of the incident light of the optical machine is the same as the propagation angle of the diffracted light after diffraction of the grating, the wave vector a0 is also used for indicating the coupled light coupled to the human eye. It should be understood that, not all vectors obtained by vector synthesis of the first grating vector and the second grating vector are shown in the figure, whether or not and how the wave vector corresponding to the vector synthesized by vector propagates in the waveguide sheet may be determined according to the positional relationship between the wave vector and each region in fig. 5, for example, the positional relationship between the wave vector a3 and each region in fig. 5 determines that the light corresponding to the wave vector a3 does not actually exist, that is, the first light does not exist, and the secondary diffracted light indicated by the wave vector a3 does not exist.
As shown in the figure, the wave vector a2 can still be completed in the ring formed by the C21 region and the C3 region, that is, the diffracted light rays of all angles of one secondary of the first light ray can be totally reflected and propagated in the waveguide sheet, so that all light rays coupled into the waveguide sheet can be coupled out by the two-dimensional grating, the problem of incomplete angle transmission of the light rays is solved, and the defect of an image displayed by the waveguide sheet is avoided.
It should be noted that, in this implementation process, only the wave vector a2 exists completely in the ring formed by the C21 region and the C3 region, that is, the first diffracted light rays of all angles corresponding to the wave vector a2 can propagate through total reflection in the waveguide sheet, so as to propagate the light rays (R0 in the drawing) incident to the light ray coupling-in region a at each angle into the light ray coupling-out region B as shown in fig. 6, and the pupil expansion can be performed along two main directions in the light ray coupling-out region B, so as to ensure that all the light rays can perform two-dimensional pupil expansion in the light ray coupling-out region B and be coupled out to human eyes (such as the emergent light ray R1 in the drawing) in the light ray coupling-out region B.
Referring to fig. 7 and fig. 8, fig. 7 is a wave vector diagram according to still another embodiment of the present application, and fig. 8 is a schematic diagram of a light propagation path according to another embodiment of the present application.
In another implementation process, in the case that the wave vector a2 corresponding to all the angle light exists completely in the ring formed by the C21 region and the C3 region, the wave vector a1 corresponding to the first light exists partially or completely in the ring formed by the C21 region and the C3 region under the action of the second grating vector K3.
In this implementation, as shown in fig. 8, since the first diffracted light beams of all angles corresponding to the wave vector a2 can propagate through total reflection in the waveguide sheet, in the light coupling-out region, the light beam (shown as R0 in the drawing) incident to the light coupling-in region at each angle can be pupil-expanded along two main directions, such as the first direction and the second direction perpendicular to each other, and part of the angle light beams or all the angle light beams indicated by the wave vector a3 in the C3 region can also be pupil-expanded along the third direction, so that the pupil-expanded light beam (shown as R1 in the drawing) can be coupled out to the human eye.
Through the design of the grating period and the grating structure of the two-dimensional grating, all view field light coupled into the waveguide sheet can be coupled out by the two-dimensional grating in the light coupling-out area, two-dimensional pupil expansion of all view field light in the light coupling-out area is ensured, and rainbow effect of external light in two diffraction directions of the two-dimensional grating is eliminated, so that the waveguide sheet can normally display images.
In one embodiment, the diffraction microstructure device disposed in the light coupling region is a grating, and a grating period of the grating is greater than or equal to 250 nm and less than 450 nm.
It is understood that the diffractive microstructure device provided with the light incoupling region may be any optical device capable of coupling light incident on the light incoupling region into the waveguide, including but not limited to a one-dimensional grating or a two-dimensional grating. When the diffraction microstructure device arranged in the light coupling-in area is a one-dimensional grating, the grating period of the one-dimensional grating is more than or equal to 250 nanometers and less than 450 nanometers; and when the diffraction microstructure device arranged in the light coupling-in area is a two-dimensional grating, at least one grating period of the two-dimensional grating is more than or equal to 250 nanometers and less than 450 nanometers so as to realize the coupling of the incident light into the waveguide sheet.
In an embodiment, an included angle between a periodic direction of the grating disposed in the light coupling-in area and the preset direction is less than or equal to 45 °.
The preset direction is a long side direction of a rectangle, or an x-axis direction, where the light coupling-in area and the light coupling-out area are minimum circumscribed, that is, an included angle between a periodic direction of the grating disposed in the light coupling-in area and the long side direction or the x-axis direction of the rectangle, where the light coupling-in area and the light coupling-out area are minimum circumscribed, is less than or equal to 45 °.
Referring to fig. 9 and fig. 10, fig. 9 is a schematic view of a waveguide sheet according to an embodiment of the present application, and fig. 10 is a schematic view of a light propagation path according to another embodiment of the present application.
In an embodiment, the diffraction microstructure device disposed in the light coupling-out area further includes a one-dimensional grating, and the one-dimensional grating is disposed adjacent to the two-dimensional grating; the two-dimensional grating is also used for carrying out two-dimensional pupil expansion processing on the first light rays incident to the two-dimensional grating, and the one-dimensional grating is used for carrying out one-dimensional pupil expansion processing on the light rays subjected to the two-dimensional pupil expansion processing.
As shown in fig. 9, the light coupling-out area B includes an area S1 and an area S2, where the area S1 is adjacently disposed in the area S2, a one-dimensional grating is disposed in the area S1, a two-dimensional grating is disposed in the area S2, after the first light coupled into the waveguide sheet in the light coupling-in area a propagates to the light coupling-out area B, the first light passes through the area S2 and then passes through the area S1, it can be understood that the two-dimensional grating in the area S2 completes the two-dimensional pupil expansion of the light in the area S2, the one-dimensional grating in the area S1 performs the one-dimensional pupil expansion of the two-dimensional pupil expansion of the light in the area S1, and finally, the light propagation path in the whole area of the light coupling-out area B is shown in fig. 10.
In an embodiment, the diffractive microstructure device provided with the light incoupling region and the light outcoupling region comprises at least one of a surface relief grating, a volume hologram grating, and a super-structured surface.
Illustratively, the diffractive microstructure device is at least one of a surface relief grating, a volume holographic grating, a super-structured surface to couple light incident on the grating or/and the super-structured surface into the waveguide sheet.
In a specific implementation process, the waveguide sheet couples light into the waveguide sheet through a diffraction microstructure device arranged in a light coupling-in area to obtain first light rays propagating in the waveguide sheet, and when the first light rays propagate to a light coupling-out area and are incident to the two-dimensional grating, the two-dimensional grating diffracts the first light rays to obtain first diffracted light rays; the first diffracted light is capable of total reflection propagation in the waveguide plate, and the light outcoupling region is further configured to couple the first diffracted light out to a human eye such that a user can view an image displayed by the waveguide plate within the light outcoupling region.
It is understood that the two-dimensional grating can realize that the first light rays propagating in the waveguide sheet are coupled out, and simultaneously, the second diffraction light rays generated by the second light rays irradiated from the outside are emitted to the outside of the waveguide sheet at the first preset emergent angle, so that rainbow patterns are prevented from being observed by human eyes when image display is realized, and the use experience of a user is improved.
In an embodiment, a distance from a center point of the light coupling-in region to any boundary tangent line of the light coupling-out region along the predetermined direction is less than or equal to 5 mm.
The center point of the light coupling-in area represents the area center point of the light coupling-in area, and the preset direction is the long side direction of the minimum circumscribed rectangle of the light coupling-in area and the light coupling-out area. The light coupling-in area and the light coupling-out area are not overlapped, and the light coupling-in area is arranged close to the boundary of the light coupling-out area in the preset direction, so that the AR display device manufactured by the waveguide sheet has better image display effect, for example, the brightness and the display uniformity of an image can be improved.
In one embodiment, the waveguide sheet further includes a light turning region; the light turning region is adjacently arranged in the light coupling-in region and the light coupling-out region, and is used for transmitting the first light obtained by coupling in from the light coupling-in region to the light coupling-out region.
For example, when the first light passes through the light turning region, total reflection or diffraction can occur and the first light is transmitted to the light coupling-out region, so that the first light is transmitted from the light coupling-in region to the light coupling-out region.
According to the waveguide sheet provided by the embodiment, the two-dimensional grating with the grating period of more than or equal to 200 nanometers and less than or equal to 350 nanometers in any period direction is arranged in the light coupling-out area, so that the second diffracted light corresponding to the second light irradiated to the two-dimensional grating from the outside of the waveguide sheet can be emitted to the outside of the waveguide sheet at the first preset emergent angle, the second diffracted light is prevented from being observed by a user, and the effect of weakening or eliminating rainbow lines is realized.
Referring to fig. 11, fig. 11 is a schematic structural diagram of a display device according to an embodiment of the present application.
In an embodiment, the display device includes a light engine and a waveguide sheet as provided in any of the above embodiments, wherein the light coupling-in region in the waveguide sheet is used to couple light emitted from the light engine into the waveguide sheet, and couple light propagating in the waveguide sheet out to human eyes through the light coupling-out region in the waveguide sheet.
It should be appreciated that, the waveguide sheet provided in any of the embodiments above can couple light emitted by the optical engine into the waveguide sheet, and the two-dimensional grating in the waveguide sheet, which is disposed in the light coupling-out area, can diffract and couple light propagating through total reflection in the waveguide sheet, so that a user can see an image displayed in the waveguide sheet, and the two-dimensional grating can emit second diffracted light generated by externally illuminating the two-dimensional grating to the outside of the waveguide sheet at a first preset emission angle, so that the eyes of the user are prevented from observing rainbow patterns, and therefore, color strips are not present in an external environment image watched through the waveguide sheet, the visual effect is cleaner and more comfortable, and the use experience of the display device of the user is improved. The specific structure and implementation principle of the waveguide sheet can be referred to above, and will not be described herein.
The display device may include an AR wearable device, such as AR glasses.
It is to be understood that the terminology used in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. 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 also be understood that the term "and/or" as used in this 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. It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or system 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 system. 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 system that comprises the element.
The foregoing embodiment numbers of the present application are merely for describing, and do not represent advantages or disadvantages of the embodiments. While the invention has been described with reference to certain preferred embodiments, it will be understood by those skilled in the art that various changes and substitutions of equivalents may be made and equivalents will be apparent to those skilled in the art without departing from the scope of the invention. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.
Claims (10)
1. The waveguide sheet is characterized by comprising a light coupling-in area and a light coupling-out area, wherein the light coupling-in area and the light coupling-out area are respectively provided with a diffraction microstructure device, the diffraction microstructure devices arranged in the light coupling-out area are two-dimensional gratings, and the grating period of the two-dimensional gratings in any period direction is more than or equal to 200 nanometers and less than or equal to 350 nanometers;
the diffractive microstructure device arranged in the light coupling-in region is used for coupling light into the waveguide sheet; the two-dimensional grating is used for diffracting first light rays propagating in the waveguide sheet to obtain first diffracted light rays, the two-dimensional grating is also used for diffracting second light rays irradiated to the two-dimensional grating from the outside of the waveguide sheet to obtain second diffracted light rays, and the second diffracted light rays are emitted to the outside of the waveguide sheet at a first preset emergent angle.
2. The waveguide sheet according to claim 1, wherein an included angle between a first period direction of the two-dimensional grating and a second period direction of the two-dimensional grating is smaller than 90 °, the two-dimensional grating diffracts a second light beam irradiated to the two-dimensional grating from outside the waveguide sheet to obtain a second diffracted light beam and a third diffracted light beam, and the third diffracted light beam is emitted to outside the waveguide sheet at a second preset emission angle.
3. The waveguide sheet according to claim 2, wherein a grating period of the two-dimensional grating in the first period direction and a grating period in the second period direction are each 200 nm or more and 350 nm or less.
4. The waveguide sheet according to claim 1, wherein the diffraction microstructure device provided in the light coupling-in region is a grating having a grating period of 250 nm or more and 450 nm or less.
5. The waveguide plate of claim 4, wherein the light coupling-in area is arranged such that an angle between a periodic direction of the grating and a predetermined direction is 45 ° or less.
6. The waveguide sheet according to any one of claims 1 to 5, wherein the diffractive microstructure device provided with the light outcoupling region further comprises a one-dimensional grating, the one-dimensional grating being provided adjacent to the two-dimensional grating; the two-dimensional grating is also used for carrying out two-dimensional pupil expansion processing on the first light rays incident to the two-dimensional grating, and the one-dimensional grating is used for carrying out one-dimensional pupil expansion processing on the light rays subjected to the two-dimensional pupil expansion processing.
7. The waveguide of claim 1, wherein the diffractive microstructure device disposed in the light incoupling region and the light outcoupling region comprises at least one of a surface relief grating, a volume hologram grating, and a super-structured surface.
8. The waveguide according to any one of claims 1 to 5, wherein a distance from a center point of the light coupling-in region to any boundary tangent of the light coupling-out region along a predetermined direction is 5 mm or less.
9. The waveguide sheet according to any one of claims 1 to 5, wherein the waveguide sheet further comprises a light turning region; the light turning region is arranged adjacent to the light coupling-in region and the light coupling-out region, and is used for transmitting the first light obtained by coupling in from the light coupling-in region to the light coupling-out region.
10. A display device comprising a light engine and a waveguide according to any of claims 1-9, wherein a light incoupling region in the waveguide is arranged to couple light exiting the light engine into the waveguide and to couple light propagating within the waveguide out to a human eye through a light outcoupling region in the waveguide.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311176392.2A CN117388975A (en) | 2023-09-12 | 2023-09-12 | Waveguide sheet and display device |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311176392.2A CN117388975A (en) | 2023-09-12 | 2023-09-12 | Waveguide sheet and display device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN118131389A (en) * | 2024-05-10 | 2024-06-04 | 歌尔光学科技有限公司 | Light guide device, method for determining inhibition zone, optical system and display device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN118131389A (en) * | 2024-05-10 | 2024-06-04 | 歌尔光学科技有限公司 | Light guide device, method for determining inhibition zone, optical system and display device |
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