CN218547139U - Super-structured optical waveguide and near-to-eye display device - Google Patents
Super-structured optical waveguide and near-to-eye display device Download PDFInfo
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Abstract
The utility model relates to a super structure optical waveguide and near-to-eye display device, it can solve the problem that current optical waveguide can't realize carrying out regulation and control to the transmission form of light. The super-structured optical waveguide includes a waveguide substrate and a set of super-structured surfaces. The waveguide substrate has an incoupling region, an outcoupling region, and a plurality of total reflection regions in the light path between the incoupling region and the outcoupling region. The super-structure surface group comprises a reflection super-structure surface arranged in at least one total reflection area in the waveguide substrate, and the reflection super-structure surface is used for carrying out transmission form regulation and control on light beams propagating in the waveguide substrate.
Description
Technical Field
The utility model relates to an optical waveguide technical field especially relates to a super structure optical waveguide and near-to-eye display device.
Background
A flat optical waveguide is widely used in recent years for near-eye display devices such as Augmented Reality (AR) as an optical path folding device having a planar thin plate structural feature. The flat optical waveguide can realize the light path folding of the micro display screen information under the limitation of a thinner volume, and simultaneously completely presents real scene information, so the flat optical waveguide becomes a core element for realizing double-scene presentation of the near-eye display equipment.
The conventional slab optical waveguide is usually a grating waveguide, such as a surface relief grating waveguide or a holographic grating waveguide, and realizes light coupling-in, pupil expanding and light coupling-out of the grating waveguide through a diffraction modulation effect of a grating on the light. However, the grating waveguide can only realize the deflection function of the optical path, that is, parallel light becomes parallel light propagating along another direction after being diffracted and deflected, and the transmission form (such as focal power, aberration or polarization state) of light in the waveguide cannot be controlled. For example, fig. 1A and 1B show schematic diagrams of optical path transmission of a conventional surface relief grating waveguide; specifically, the grating of the coupling-in region of the surface relief grating waveguide is positioned on the same side surface where light enters, and the grating of the expanding pupil and the grating of the coupling-out region are positioned on the other side surface; therefore, after the light enters the waveguide at the coupling-in end, the light can directionally propagate in the waveguide along the Z-shaped optical path by utilizing the total reflection of the interfaces at the two sides, and finally is transmitted out of the waveguide at the coupling-out end. On one hand, because the reflection times of light in the waveguide are very many, the actual optical path of the light is long although the surface relief grating waveguide is thin; on the other hand, the coupling-in end and the coupling-out end are respectively positioned at different positions of the waveguide, so that the surface of the surface relief grating can realize the dislocation transmission of the optical path; that is, the surface relief grating waveguide can realize the functions of optical path folding and dislocation transmission.
However, for the grating waveguide, the diffraction physical process and the constant line period structure of the grating are limited, so that the deflection effect of the grating region on the light is limited to the deflection with a constant angle, that is, for the light beam incident on the grating surface in parallel, the light beam is deflected with the same angle, therefore, the grating waveguide only can play a role of directionally changing the transmission direction of the light beam, and cannot regulate and control the form (such as focal power, aberration or polarization state, and the like) of the transmitted light. In addition, due to the anisotropic structure of the line grating, the light beams diffracted by the grating often produce orthogonal polarization components in an uncontrolled manner, and generally form complicated elliptically polarized light, which may have an uncontrollable effect on the process of transmitting light energy in the optical system.
SUMMERY OF THE UTILITY MODEL
An advantage of the utility model is that a super structure optical waveguide and near-to-eye display device is provided, it can solve the unable problem that adjusts and control of transmission form that realizes the light of current grating waveguide.
Another advantage of the present invention is to provide a super structure optical waveguide and near-to-eye display device, wherein, in an embodiment of the present invention, super structure optical waveguide can utilize super structure surface to the nimble regulation and control ability of light, changes the transmission form of light in the waveguide to only adopt single super structure optical waveguide just can realize the reimaging to the image source.
Another advantage of the present invention is to provide a super structure optical waveguide and near-to-eye display device, wherein, in an embodiment of the present invention, the super structure optical waveguide can make the near-to-eye display device omit complicated optical imaging system, only keep image source and optical waveguide and can realize near-to-eye imaging, effectively compress the number of elements (such as lens or polaroid) and the overall dimensions of the near-to-eye display optical system, which has important application value in the AR field.
Another advantage of the present invention is to provide a super-structured optical waveguide and near-to-eye display device, wherein to achieve the above objects, expensive materials or complex structures need not be employed in the present invention. Therefore, the present invention successfully and effectively provides a solution that not only provides a simple super-structured optical waveguide and near-to-eye display device, but also increases the utility and reliability of the super-structured optical waveguide and near-to-eye display device.
In order to realize the utility model discloses an above-mentioned at least advantage or other advantages and purposes, the utility model provides a super structure optical waveguide, include:
a waveguide substrate having an incoupling region, an outcoupling region, and a plurality of total reflection regions in an optical path between the incoupling region and the outcoupling region; and
the super-structure surface group comprises a reflection super-structure surface arranged in at least one total reflection area in the waveguide substrate, and the reflection super-structure surface is used for carrying out transmission form regulation and control on light beams propagating in the waveguide substrate.
According to an embodiment of the application, the set of unstructured surfaces comprises a outcoupling unstructured surface arranged in the outcoupling region, the outcoupling unstructured surface having a polarization-splitting control structure for controlling a first polarized light propagating in the waveguide matrix to outcouple the first polarized light from the outcoupling region while allowing a second polarized light having a polarization state orthogonal to the polarization state of the first polarized light to pass through the waveguide matrix in an original form.
According to one embodiment of the present application, the polarization state P of the first polarized light 1 The following formula is satisfied: p 1 ＝R(θ)[1 0] T +AR(η)[1 iσ] T (ii) a And the polarization state P of the second polarized light 2 The following formula is satisfied: p 2 ＝R(θ-π/2)[1 0] T +AR(η-π/2)[1-iσ] T (ii) a In the formula: r is a rotation matrix; theta and eta are arbitrary rotation angles, respectively; σ is the rotation direction of the circularly polarized light, and σ = +/-1; a is an amplitude intensity coefficient of circularly polarized light with respect to linearly polarized light.
According to one embodiment of the present application, the meta-surface in the meta-surface group is composed of a plurality of nano-pillars periodically arranged in position.
According to one embodiment of the present application, the nanopillars have two mutually perpendicular axes of symmetry on their bottom surfaces.
According to an embodiment of the present application, the nano-pillars are one or more of rectangular pillars, elliptical pillars, diamond-shaped pillars, elliptical pillars, cross pillars, and hexagonal pillars.
According to an embodiment of the application, the metamaterial optical waveguide further comprises an outcoupling grating arranged at the outcoupling region for outcoupling the optical beam propagating within the waveguide substrate from the outcoupling region.
According to an embodiment of the application, the metamaterial optical waveguide further comprises an incoupling grating disposed at the incoupling region for coupling an optical beam into the waveguide matrix for propagation within the waveguide matrix.
According to an embodiment of the application, the set of nanostructured surfaces further comprises an incoupling nanostructured surface provided at the incoupling region for coupling a light beam into the waveguide matrix for propagation within the waveguide matrix.
According to one embodiment of the application, the reflective superstructure surface has a phase modulating structure for modulating the phase of the light beam as it propagates within the waveguide matrix to modulate the optical power and/or aberrations of the light beam.
According to an embodiment of the application, the reflective superstructure further has a polarization-modulating structure for modulating the polarization state of the light beam as it propagates within the waveguide substrate to form first polarized light propagating to the outcoupling region.
According to an embodiment of the present application, the reflective superstructure has a polarization-splitting control structure for controlling a transmission mode of a first polarized light propagating in the waveguide substrate, and a second polarized light having a polarization state orthogonal to a polarization state of the first polarized light is transmitted through the waveguide substrate in an original mode.
According to another aspect of the present application, there is further provided a near-eye display device comprising:
an image source; and
the above-mentioned super-structured optical waveguide is disposed in a light-emitting optical path of the image source, and is configured to re-image the image light emitted by the image source.
Drawings
Fig. 1A and 1B are schematic diagrams illustrating an optical path transmission principle of a conventional surface relief grating waveguide;
fig. 2 is a schematic structural diagram of a super-structured optical waveguide according to an embodiment of the present invention;
fig. 3 shows a schematic optical path diagram of a super-structured optical waveguide according to the above-described embodiment of the present invention;
fig. 4 is a schematic diagram illustrating an overall shape of a reflective super-structured surface in a super-structured optical waveguide according to the embodiment of the present invention;
fig. 5A is a schematic perspective view illustrating that the nano-pillars in the super-structured surface for reflection are rectangular pillars according to the present invention;
FIG. 5B shows a schematic bottom view of the rectangular post shown in FIG. 5A;
fig. 6 is a schematic bottom view of the nano-pillars in the reflective super-structured surface according to the present invention;
fig. 7 is a schematic bottom view of the nano-pillars in the reflective super-structured surface according to the present invention;
fig. 8 shows a first modification example of the super structured optical waveguide according to the above-described embodiment of the present invention;
fig. 9 shows a second modification example of the super structured optical waveguide according to the above embodiment of the present invention;
fig. 10 shows a third modification example of the super structured optical waveguide according to the above-described embodiment of the present invention;
fig. 11 is a schematic structural diagram of a near-eye display device according to an embodiment of the present invention.
Description of the main element symbols: 1. a super-structured optical waveguide; 10. a waveguide substrate; 101. a coupling-in region; 102. a coupling-out region; 103. a total reflection region; 11. a first total reflection surface; 12. a second total reflection surface; 20. a set of nanostructured surfaces; 21. a reflective nanostructured surface; 210. a nanopillar; 211. a rectangular column; 212. an oval post; 213. a diamond-shaped column; 22. a coupling-out superstructure surface; 23. a coupling-in superstructure surface; 30. coupling out a grating; 2. an image source.
The present invention is further described in detail with reference to the drawings and the detailed description.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts all belong to the protection scope of the present invention.
It will be understood that when an element is referred to as being "mounted on" another element, it can be directly on the other element or intervening elements may also be present. When a component is referred to as being "disposed on" another component, it can be directly on the other component or intervening components may also be present. When an element is referred to as being "secured to" another element, it can be directly secured to the other element or intervening elements may also be present.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "or/and" includes any and all combinations of one or more of the associated listed items.
Considering that the existing grating waveguide is limited by the diffraction physical process and the constant linear periodic structure of the grating, the deflection action of the grating region on light is limited to the deflection of a constant angle, so that the grating waveguide can only play a role of directionally changing the transmission direction of the light beam, and the regulation and control on the form of the transmitted light (such as focal power, aberration or polarization state and the like) cannot be realized. In order to solve the problem, the application provides a super-structured optical waveguide and a near-eye display device, which can solve the problem that the existing grating waveguide cannot regulate and control the transmission form of light.
Specifically, referring to fig. 2-7, one embodiment of the present invention provides a metamaterial optical waveguide 1 that may include a waveguide substrate 10 and a set of metamaterial surfaces 20. The waveguide body 10 has an incoupling region 101, an outcoupling region 102, and a plurality of total reflection regions 103 located in the optical path between the incoupling region 101 and the outcoupling region 102. The group of the super-structured surfaces 20 may include a reflection super-structured surface 21 disposed in at least one total reflection region 103 of the waveguide substrate 10, and the reflection super-structured surface 21 is configured to perform transmission form control on a light beam propagating in the waveguide substrate 10. It is understood that the transmission states mentioned in the present application may refer to the optical power, aberration, polarization state, etc. of the light beam.
More specifically, the reflective super-structured surface 21 may have a phase control structure for controlling the phase of the light beam propagating in the waveguide substrate 10 to modulate the focal power and/or aberration of the light beam, which facilitates the direct utilization of the super-structured optical waveguide 1 to realize the re-imaging of the image light, and facilitates the reduction or elimination of lenses in the imaging lens group to effectively compress the weight and the external dimensions of the optical system.
It is noted that, as shown in fig. 2 and 3, the waveguide substrate 10 may have a first total reflection surface 11 and a second total reflection surface 12 parallel to each other, so that the super structured optical waveguide 1 has a flat plate structure. Because the light beam can be totally reflected for multiple times on the first total reflection surface 11 and the second total reflection surface 12 of the waveguide substrate 10 when the super-structured optical waveguide 1 transmits the light beam, theoretically, a reflection super-structured surface 21 can be arranged in a region (i.e. the total reflection region 103) where the light beam contacts with the surface of the waveguide substrate 10 when each total reflection occurs, so that an ideal total reflection transmission process is broken, and further, complicated and fine light beam regulation and control are realized. It is understood that the total reflection region 103 mentioned in the present application refers to a region where the light beam coupled in via the coupling-in region 101 contacts the first total reflection surface 11 or the second total reflection surface 12 each time total reflection occurs.
In other words, the super-structured optical waveguide 1 may include a plurality of reflecting super-structured surfaces 21, and the reflecting super-structured surfaces 21 are disposed in the total reflection regions 103 of the waveguide substrate 10 in a one-to-one correspondence, so that the light beam propagating in the waveguide substrate 10 is modulated by the reflecting super-structured surfaces 21 in each shot process, thereby realizing complex and fine light beam regulation.
Alternatively, as shown in fig. 2 and fig. 3, the super-structured surface set 20 of the super-structured optical waveguide 1 may further include a coupling-out super-structured surface 22 disposed in the coupling-out region 102, where the coupling-out super-structured surface 22 has a polarization-splitting control structure for controlling the first polarized light propagating in the waveguide substrate 10 to be coupled out of the waveguide substrate 10 from the coupling-out region 102, and enabling the second polarized light having a polarization state orthogonal to the polarization state of the first polarized light to transmit through the waveguide substrate 10 in an original form. That is to say, the coupling-out super-structured surface 22 of the super-structured optical waveguide 1 can adjust and control the transmission mode of the first polarized light in the image light to change the beam mode according to the design requirement, and at the same time, the second polarized light in the environment light can transmit through the waveguide substrate 10 in the original mode, so that the user can see a high-quality virtual image through the coupling-out region 102 of the super-structured optical waveguide 1, and can see a real environment without distortion through the coupling-out region 102 of the super-structured optical waveguide 1.
It should be noted that the first polarized light mentioned in the present application may be polarized light in any form, for example, the first polarized light may be represented as a superposition of linearly polarized light in any orientation and circularly polarized light in any orientation, and it is only necessary to ensure that the polarization state of the second polarized light is orthogonal to the polarization state of the first polarized light.
More specifically, the polarization state P of the first polarized light 1 Satisfies the following formula (1):
P 1 ＝R(θ)[1 0] T +AR(η)[1 iσ] T (1)
and the polarization state P of the second polarized light 2 Satisfies the following formula (2):
P 2 ＝R(θ-π/2)[1 0] T +AR(η-π/2)[1-iσ] T (2)
in the formula: r is a rotation matrix; theta and eta are arbitrary rotation angles, respectively; σ is the rotation direction of the circularly polarized light, and σ = +/-1; a is the ratio of circularly polarized light to circularly polarized lightAmplitude intensity coefficient of linearly polarized light. It can be understood that the polarization state P of the first polarized light 1 With the polarization state P of the second polarized light 2 Has a zero inner product, i.e. the polarization state P of the first polarized light 1 And the polarization state P of the second polarized light 2 Mutually orthogonal polarization states.
It should be noted that, because the image light directly emitted from the image source generally has power and aberration, and the existing grating waveguide does not have the transmission form adjusting and controlling capability, the existing near-eye display device has to arrange a bulky and heavy imaging lens group between the image source and the grating waveguide to adjust and control the power and aberration of the image light. As shown in fig. 3, the reflective super-structure surface 21 in the super-structure optical waveguide 1 of the present application can only perform transmission configuration control on the first polarized light propagating in the waveguide substrate 10, so that the image light directly emitted via an image source can be directly coupled into the super-structure optical waveguide 1 for transmission, and the reflective super-structure surface 21 is used to control the focal power and aberration of the image light to display a high-quality virtual image through the super-structure optical waveguide 1, thereby omitting an imaging lens group with a large volume and a heavy weight, which is helpful to greatly reduce the volume and weight of the near-eye display device, and meeting the development trend of light weight and small volume of the current electronic device.
Optionally, the reflective superstructure surface 21 further has a polarization-controlling structure for controlling the polarization state of the light beam propagating in the waveguide substrate 10 to form the first polarized light propagating to the coupling-out region 102 for being coupled out of the waveguide substrate 10 by the coupling-out superstructure surface 22. Preferably, the reflective metamaterial surface 21 closest to the coupling-out region 102 on the waveguide substrate 10 has a polarization control structure, and the other reflective metamaterial surfaces 21 on the waveguide substrate 10 have a phase control structure, so as to reduce the difficulty of the structural design of the reflective metamaterial surface 21 while achieving the desired polarization imaging function.
Of course, in other examples of the present application, the reflective super-structured surface 21 may also have a polarization-splitting control structure for reflecting and controlling the transmission mode of the first polarized light propagating in the waveguide substrate 10, and transmitting the second polarized light having the polarization state orthogonal to the polarization state of the first polarized light through the waveguide substrate 10 in the original mode.
Thus, when the super-structured optical waveguide 1 is applied to a near-eye display device such as an AR device for near-eye display, a first polarized light in an image light is modulated by the reflective super-structured surface 21 during propagation in the waveguide substrate 10, so that the first polarized light is output from the waveguide substrate 10 after changing the transmission form for imaging; meanwhile, the light of the second polarization in the ambient light is not modulated by the reflective metamaterial surface 21 to directly transmit through the waveguide substrate 10, so that the light of the second polarization is output from the waveguide substrate 10 to be imaged while remaining in the original form. That is to say, the super-structured optical waveguide 1 can adjust and control the transmission form of the first polarized light in the image light to change the beam form according to the design requirement, and at the same time, the second polarized light in the environment light can transmit through the waveguide substrate 10 in the original form, so that the user can see a high-quality virtual image through the super-structured optical waveguide 1 and can see a real environment without distortion through any part of the super-structured optical waveguide 1.
Exemplarily, the polarization state of the light input into the outcoupling superstructure surface 22 (i.e. the input light), i.e. the input state of the input light, may be denoted as P in ＝P 1 +P 2 ＝[E x E y ] T In which E x And E y Respectively representing the complex amplitude information of the input light in the x direction and the y direction; the polarization state of the light (i.e., the output light) that outputs the reflective nanostructured surface 21, i.e., the output state of the output light, can be represented as P out ＝e iδ P 1 +P 2 ＝[E′ x E′ y ] T (ii) a Wherein e is iδ An additional phase shift, E ', of polarization state P1 to be tuned relative to polarization state P2' x And E' y Respectively representing the complex amplitude information of the output light in the x-direction and the y-direction. The polarization state control ability of the reflective nanostructured surface 21 of the nanostructured optical waveguide 1 for the input light can be expressed by the following formula (3):
in the formula: t is x 、T xy And T y The transformation coefficients for complex amplitude modulation of the reflecting microstructured surface 21 are determined by the structural configuration of the microstructured surface. It will be appreciated that the seven quantities in equation (3) above are all functions of the location of incidence of the metamaterial surface; the complex amplitude information referred to herein may include amplitude information indicative of intensity and phase information indicative of power and/or aberration.
Furthermore, the deflecting capability of the outcoupling superstructure 22 for the light beam can be determined by the following formula (4):
in the formula: n is 1 And n 2 Refractive indices of the incident side and the exit side of the reflecting superstructure surface 21, respectively; theta.theta. 1 And theta 2 The incident angle and the exit angle of the light beam are respectively; λ is the wavelength of the light beam;
is the rate of change of phase in the direction of the gradient. It is understood that, according to the above formula (4): the outcoupling facet 22 enables an adjustment of the beam shape when designing different phase gradients at different positions with the facet.
Alternatively, as shown in fig. 4, the meta-surface (which may include the meta-surface 21 for reflection and the meta-surface 22 for outcoupling) in the meta-surface group 20 of the present application is composed of a plurality of nano-pillars 210 periodically arranged in position. For example, fig. 4 to 7 show the shape of the nano-pillars 210 in the reflective super-structured surface 21, and the bottom surfaces of the nano-pillars 210 have two symmetry axes perpendicular to each other to achieve the polarization state control function. Thus, the nanostructured surface 21 for reflection of the present application can respectively implement differential phase control on two polarization states by adjusting the length L and the width W of the nanopillar 210 in two symmetry axis directions; in addition, the reflective metamaterial surface 21 of the present application can realize coupling conversion between two polarized lights in orthogonal polarization states by adjusting the orientation angle θ of the nano-pillar 210. It can be understood that the orientation angle θ of the nanopillars 210 mentioned in the present application refers to an included angle between a long axis direction of the nanopillars 210 and an array direction of the nanopillars 210; meanwhile, the influence of the length L, the width W, and the orientation angle θ of the nanopillar 210 on the phase and the coupling relationship of each polarization state is generally determined through numerical simulation, and as can be seen from the characteristic parameters of the nanopillar, the adjustable parameters of the present application include the length L, the width W, the orientation angle θ, and the shape of the nanopillar.
Alternatively, the nanopillar 210 may be implemented as a rectangular pillar 211 as shown in fig. 5A and 5B, an oval pillar 212 as shown in fig. 6, or a diamond pillar 213 as shown in fig. 7. Of course, in other examples of the present application, the nano-pillars 210 may also be, but are not limited to being, implemented as nano-pillars having two orthogonal symmetry axes, such as ellipsoid pillars, cross pillars, or hexagonal pillars.
Alternatively, the nano-pillars 210 are usually made of a high refractive index light-transmitting medium. For example, the refractive index of the nanopillars 210 is greater than 2.
According to the above-mentioned embodiment of the present application, as shown in fig. 2 and fig. 3, the group of the metamaterial surfaces 20 of the metamaterial optical waveguide 1 can further include a coupling-in metamaterial surface 23 disposed at the coupling-in region 101 for coupling the light beam into the waveguide substrate 10 to be reflected and transmitted in the waveguide substrate 10. Optionally, the coupling-in super-structure surface 23 may also have a polarization-splitting control structure, which is used to modulate the first polarized light to couple into the waveguide substrate 10, and make the second polarized light with a polarization state orthogonal to the polarization state of the first polarized light transmit through the waveguide substrate 10 in an original form. It is understood that the outcoupling superstructure surface 22 and the incoupling superstructure surface 23 mentioned in the present application may have a polarization-splitting control structure as well as the reflective superstructure surface 21, as long as the desired outcoupling and incoupling functions can be achieved, and the present application will not be described in detail.
Alternatively, as shown in fig. 2 and 3, the outcoupling relief surface 22 and the incoupling relief surface 23 are located on the same side of the waveguide substrate 10. For example, the outcoupling superstructure surface 22 and the incoupling superstructure surface 23 are both located at the first total reflection surface 11 of the waveguide substrate 10, so that the coupling-in and coupling-out of light beams from the first total reflection surface 11 is adapted to the overall structural layout of the near-eye display device. It will be appreciated that the outcoupling relief surface 22 and the incoupling relief surface 23 may also be located on different sides of the waveguide body 10, respectively. It is understood that the super-structured surface of the present application can be, but is not limited to, formed on the surface of the waveguide substrate 10 by etching or embossing, and the details of the present application are not repeated herein.
It should be noted that, although in the above-mentioned embodiment of the present application, the number of the reflective metamaterial surfaces 21 in the metamaterial optical waveguide 1 is equal to the number of the total reflection regions 103 in the waveguide substrate 10, so that the reflective metamaterial surfaces 21 are disposed in one-to-one correspondence to all the total reflection regions 103 in the waveguide substrate 10; however, in other examples of the present application, the number of the reflective super-structure surfaces 21 may be less than the number of the total reflection regions 103, so that the light beam is not modulated by the super-structure surfaces in each reflection process, but may be flexibly configured in various forms such as a super-structure surface, a grating, a medium total reflection, and the like.
Exemplarily, fig. 8 shows a first variant example of the super structured optical waveguide 1 according to the above-described embodiment of the present application. This super structured optical waveguide 1 according to the first modified example of the present application is different from the above-described embodiment according to the present application in that: the number of the reflective super-structure surfaces 21 may be less than the number of the total reflection regions 103 on the waveguide substrate 10, that is, the reflective super-structure surfaces 21 are disposed in the total reflection regions 103 of the waveguide substrate 10 in a one-to-one correspondence, so that the first polarized light propagating through the waveguide substrate 10 is not only modulated by the super-structure surfaces in some reflection processes, but also totally reflected by the first total reflection surface 11 or the second total reflection surface 12 in other reflection processes, thereby flexibly using two types of super-structure surfaces and medium total reflection.
Alternatively, as shown in fig. 8, the total reflection regions 103 adjacent to the coupling-in region 101 and the coupling-out region 102, respectively, are not provided with the reflective super-structured surface 21, so that the first polarized light coupled in from the coupling-in region 101 is firstly totally reflected and then modulated by the reflective super-structured surface 21, and the first polarized light modulated by the reflective super-structured surface 21 is firstly totally reflected and then coupled out from the coupling-out region 102, which is helpful for designing the coupling-in structure and the coupling-out structure on the waveguide substrate 10. It is understood that, in other examples of the present application, the number (number of times of use) and the position of the reflective superstructure surface 21 may not be limited, as long as the beam shape can be changed according to certain design requirements, and the description of the present application is omitted.
It is to be noted that although the optical waveguide 1 uses a super-structured surface to couple in and out the light beam in the first modified example of the present application, the optical waveguide 1 may use a grating to couple in and out the light beam in other examples of the present application. For example, fig. 9 shows a second modified example of the super structured optical waveguide 1 according to the above-described embodiment of the present application. This super structured optical waveguide 1 according to the second modified example of the present application differs from the above-described first modified example according to the present application in that: the outcoupling region 102 of the waveguide substrate 10 is provided with an outcoupling grating 30 instead of the outcoupling superstructure surface 22, so that light beams transmitted at the waveguide substrate 10 are outcoupled from the waveguide substrate 10 via the outcoupling grating 30 to be incident on the human eye. In other examples of the present application, the coupling-in super-structure surface 23 may be replaced by a coupling-in grating, that is, the coupling-in region 101 of the waveguide substrate 10 may be provided with a coupling-in grating (not shown) for coupling light beams into the waveguide substrate 10 to propagate in the waveguide substrate 10, which is not described herein again.
Optionally, the outcoupling grating 30 and the outcoupling superstructure surface 23 are located on the same side of the waveguide substrate 10. For example, as shown in fig. 9, the coupling-out grating 30 and the coupling-in super-structured surface 23 are both located on the first total reflection surface 11 of the waveguide substrate 10, so that the light beams are coupled in and out from the first total reflection surface 11, and the overall structural layout of the near-eye display device is adapted.
It should be noted that, although the coupling-in super-structure surface 23 is located on the first total reflection surface 11 of the waveguide substrate 10 in the second modified example of the present application, so that the light beam is coupled in through the coupling-in super-structure surface 23 when propagating to the waveguide substrate 10, in the third modified example of the present application, as shown in fig. 10, the coupling-in super-structure surface 23 may also be located on the second total reflection surface 12 of the waveguide substrate 10, so that the image light is coupled in and transmitted in the waveguide substrate 10 by the coupling-in super-structure surface 23 after propagating to the second total reflection surface 12 through the first total reflection surface 11.
It should be noted that, according to another aspect of the present application, as shown in fig. 11, an embodiment of the present application may further provide a near-eye display device, which may include the above-mentioned super-structured optical waveguide 1 and an image source 2, where the super-structured optical waveguide 1 is disposed in a light emitting optical path of the image source 2, and is used to re-image an image reflected by the image source 2, so as to implement near-eye imaging without an imaging optical system. In other words, the image source 2 mentioned in the present application may be a micro display screen without an additional imaging optical system such as an imaging lens group, and the near-eye imaging can be realized by directly providing the super-structured optical waveguide 1 with image light, which helps to reduce the overall weight and volume of the near-eye display device.
Alternatively, as shown in fig. 3, the image source 2 is adapted to provide a first polarization state P 1 Of (e) image light (i.e., light of the first polarization). Of course, in other examples of the application, the image source 2 may also provide image light having an unpolarized state, so that only the first polarization coupled into the image light is modulated with the nanostructured surface.
It can be understood that, because the ambient light is the natural light usually, unpolarized light, therefore the super structure surface of this application can not regulate and control the second polarized light in this ambient light, but can regulate and control the first polarized light in this ambient light, so in order to eliminate the first polarized light in this ambient light and probably produce the influence to watching of real image, this super structure optical waveguide 1 can use with the cooperation of polarization filter to the first polarized light in the filtering ambient light, make the user see undistorted and clear real environment. In addition, the super-structured optical waveguide 1 of the present application is not limited to be applied to a near-eye display device to perform a near-eye display function, but can also be applied to other electronic devices to perform a desired display function, which is not described in detail herein.
The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above examples only represent some embodiments of the present invention, and the description thereof is more specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the concept of the present invention, several variations and modifications can be made, which all fall within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.
Claims (13)
1. A nanostructured optical waveguide comprising:
a waveguide substrate having a coupling-in region, a coupling-out region, and a plurality of total reflection regions in an optical path between the coupling-in region and the coupling-out region; and
the super-structure surface group comprises a reflection super-structure surface arranged in at least one total reflection area in the waveguide substrate, and the reflection super-structure surface is used for carrying out transmission form regulation and control on light beams propagating in the waveguide substrate.
2. The microstructured optical waveguide of claim 1, wherein the set of microstructured surfaces comprises a outcoupling microstructured surface disposed in the outcoupling region, the outcoupling surface having a polarization-splitting control structure for controlling a first polarized light propagating in the waveguide substrate to be outcoupled from the outcoupling region and allowing a second polarized light having a polarization state orthogonal to the polarization state of the first polarized light to pass through the waveguide substrate in an original form.
3. The microstructured optical waveguide of claim 2, wherein the first polarized light has a polarization state P 1 The following formula is satisfied: p 1 ＝R(θ)[1 0] T +AR(η)[1 iσ] T (ii) a And the polarization state P of the second polarized light 2 The following formula is satisfied: p 2 ＝R(θ-π/2)[ 0] T +AR(η-π/2)[1 -iσ] T (ii) a In the formula: r is a rotation matrix; theta and eta are arbitrary rotation angles, respectively; σ is the rotation direction of the circularly polarized light, and σ = +/-1; a is an amplitude intensity coefficient of circularly polarized light with respect to linearly polarized light.
4. The microstructured optical waveguide of claim 3, wherein the microstructured surfaces of the set of microstructured surfaces are formed by a plurality of nano-pillars arranged periodically.
5. The nanostructured optical waveguide of claim 4, wherein the bottom surface of the nanopillars has two mutually perpendicular axes of symmetry.
6. The super structured optical waveguide according to claim 5 wherein the nano-pillars are one or more of rectangular pillars, elliptical pillars, diamond-shaped pillars, elliptical pillars, cross-shaped pillars, and hexagonal pillars.
7. The optical waveguide of claim 1 further comprising an outcoupling grating disposed at the outcoupling region for outcoupling a light beam propagating in the waveguide substrate from the outcoupling region.
8. The optical waveguide of any one of claims 1 to 7 further comprising an incoupling grating disposed at the incoupling region for coupling a light beam into the waveguide matrix for propagation within the waveguide matrix.
9. The microstructured optical waveguide of any one of claims 1-7, wherein the set of microstructured surfaces further comprises an incoupling microstructured surface disposed at the incoupling region, the incoupling microstructured surface configured to couple a light beam into the waveguide substrate to propagate within the waveguide substrate.
10. The unstructured optical waveguide of any of claims 1 to 7, wherein the reflective unstructured surface is provided with phase control structures for controlling the phase of the light beam as it propagates within the waveguide matrix to modulate the optical power and/or aberrations of the light beam.
11. The microstructured optical waveguide of any of claims 1-7, wherein the reflective microstructured surface further comprises a polarization modifying structure configured to modify a polarization state of a light beam as it propagates through the waveguide substrate to form a first polarized light beam that propagates to the outcoupling region.
12. The unstructured optical waveguide of any of claims 1 to 7, wherein the reflective unstructured surface has a polarization-splitting control structure for reflecting and controlling a transmission form of a first polarized light propagating in the waveguide matrix, and transmitting a second polarized light having a polarization state orthogonal to a polarization state of the first polarized light in an original form through the waveguide matrix.
13. A near-eye display device, comprising:
an image source; and
the super structured light guide according to any one of claims 1 to 12, arranged in a light emitting optical path of the image source for re-imaging image light emitted by the image source.
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Assignee: Zhejiang Shunwei Technology Co.,Ltd. Assignor: SUNNY OPTICAL (ZHEJIANG) RESEARCH INSTITUTE Co.,Ltd. Contract record no.: X2024330000055 Denomination of utility model: Super structured optical waveguides and near eye display devices Granted publication date: 20230228 License type: Common License Record date: 20240515 |