CN218601510U - Light guide system and projection equipment - Google Patents

Abstract

The present Shen Ben application proposes a light guide system comprising: the optical waveguide comprises an optical waveguide body, an in-coupling grating arranged in an in-coupling area and an out-coupling grating arranged in an out-coupling area, wherein the optical waveguide body comprises the in-coupling area and the out-coupling area; the coupling grating is used for receiving incident light and coupling the incident light into the optical waveguide, so that the incident light is totally reflected in the optical waveguide and is coupled out from a coupling grating arranged in the coupling-out area, wherein the value of a grating vector k1, a grating vector k2 and a grating vector k3 satisfies that k2/k1 is more than or equal to 1 and less than or equal to 1.3,1 is more than or equal to k3/k1 is more than or equal to 1.3. In the light guide system provided by the embodiment, in the propagation process of light, the values of the grating vector k1, the grating vector k2 and the grating vector k3 satisfy that k2/k1 is more than or equal to 1 and less than or equal to 1.3,1 is more than or equal to k3/k1 and less than or equal to 1.3, so that the propagation of image light through the waveguide is ensured, no dispersion occurs, and image light with a larger angle can be transmitted more stably. The application also provides a projection device.

Description

Light guide system and projection equipment

Technical Field

The application relates to the technical field of projection, in particular to a light guide system and projection equipment.

Background

Augmented Reality (AR) is a display technology that collects real world information in real time and combines virtual information, images, and the like with the real world, is expected to become a new generation of information interaction terminal following personal computers and smart phones, and has a wide market scale and imagination space. Firstly, in the information display, the AR is not limited to an entity screen any more, but can be displayed in the whole physical space, and virtual information is displayed in real time on the basis of a physical entity in a virtual-real combination mode, namely augmented reality display; secondly, in the aspect of human-computer interaction, instruction collection can break through an operation interface of an entity, and a more natural and convenient interaction mode such as voice, gestures, images and the like is used, so that a human-computer interaction mode is more like natural communication with people.

The projection devices in AR devices are used to generate projection display images, among which are mainly LCoS or DMD based projection systems.

Liquid crystal On Silicon (LCoS) is a new type of microdisplay technology that combines semiconductor and LCD technologies. It is often necessary to provide one or more PBS prisms that are bulky as part of the illumination system, and therefore the overall volume and weight of the device is large. The DLP projection display technology is a projection display technology taking a DMD device as a core, a DMD chip is applied to form a projection display system, and the DLP projection system generally adopts a light source with an ellipsoidal reflecting bowl and a square rod illumination system, so that the illumination system has the problem of generally large volume.

For projection equipment such as AR equipment, the arrangement of gratings in the projection equipment in the prior art is prone to dispersion, which is not favorable for transmitting image light with a large angle.

SUMMERY OF THE UTILITY MODEL

In a first aspect, the present application provides a light guide system comprising: the optical waveguide comprises an optical waveguide body, an in-coupling grating arranged in an in-coupling area and an out-coupling grating arranged in an out-coupling area, wherein the optical waveguide body comprises the in-coupling area and the out-coupling area; the coupling grating is used for receiving incident light and coupling the incident light into the optical waveguide, so that the incident light is totally reflected in the optical waveguide and is coupled out from a coupling-out grating arranged in a coupling-out area, wherein the coupling grating is a one-dimensional grating and is provided with a grating vector k1, the coupling-out grating is provided with a grating vector k2 and a grating vector k3, the grating vector k1, the grating vector k2 and the grating vector k3 form a closed-loop triangle, and the values of the grating vector k1, the grating vector k2 and the grating vector k3 meet the condition that k2/k1 is more than or equal to 1 and less than or equal to 1.3,1 is more than or equal to k3/k1 and less than or equal to 1.3.

In some embodiments, the out-coupling grating is a two-dimensional grating, which further comprises an equivalent grating vector kx, the grating vector kx of the out-coupling grating being in the same direction and magnitude as the grating vector k1 of the in-coupling grating.

In some embodiments, the outcoupling grating is composed of two one-dimensional outcoupling gratings, wherein grating vectors of the two one-dimensional outcoupling gratings are k2 and k3, respectively.

In some embodiments, the outcoupling grating is composed of a plurality of composite gratings, each of which is composed of two one-dimensional outcoupling gratings whose grating vectors are k2 and k3, respectively.

In some embodiments, the array shape of the two-dimensional grating is a diamond, triangle, circle, or ellipse.

In some embodiments, the depth of the outcoupling grating is 30nm to 200nm.

In some embodiments, the wave vector diagram of the optical waveguide has a first boundary that satisfies a total reflection range and a second boundary that satisfies a maximum wave vector of the optical waveguide, the image information transmitted by the incident light, and an angular spectrum information region formed in the wave vector diagram of the optical waveguide is located between the first boundary and the second boundary, and the angular spectrum information region includes complete image information.

In some embodiments, the refractive index of the optical waveguide is 1.5 to 2.4.

In a second aspect, the present application proposes a projection device comprising the above-mentioned island system, and light source means arranged at the light entrance side of the light guide system for sending image light to be incident on the incoupling zone of said light guide system.

The light guide system provided by the embodiment adopts the light guide member and the grating structure to emit the illumination light, the whole volume and the weight are small, meanwhile, in the transmission process of the light, the path in the wave vector diagram of the light guide system provided by the application is an equilateral triangle, and the values of the grating vector k1, the grating vector k2 and the grating vector k3 meet that k2/k1 is more than or equal to 1 and less than or equal to 1.3,1 is more than or equal to k3/k1 and less than or equal to 1.3. The transmission of image light through the waveguide is ensured, no dispersion occurs, and image light with a larger angle can be transmitted more stably.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the description below are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings may be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a projection apparatus according to a first embodiment of the present application;

fig. 2 is a wave vector diagram of a single-layer waveguide in a light guide system of a projection apparatus according to a first embodiment of the present application.

Fig. 3 is a schematic diagram of a k vector of a grating in a wave vector diagram of a single-layer waveguide in a light guide system of a projection apparatus according to a first embodiment of the present application.

FIG. 4 is a schematic diagram of a k-vector of a grating in a wave vector diagram of a single-layer waveguide in a light guide system of a projection apparatus according to a first embodiment of the present application in another arrangement of the grating;

FIG. 5 is a schematic diagram of a k-vector of a grating in a wave vector diagram of a single-layer waveguide in a light guide system of a projection apparatus according to a first embodiment of the present application in a still further arrangement of the grating;

FIG. 6 is a schematic diagram of a grating k vector in a light guide system of a projection apparatus according to a first embodiment of the present application;

FIG. 7 is a schematic view of a grating k vector in a light guide system of a projection apparatus according to a second embodiment of the present application;

fig. 8 is another schematic diagram of a grating k vector in a light guide system of a projection apparatus according to a second embodiment of the present application.

Detailed Description

In order to make the technical solution better understood by those skilled in the art, the technical solution in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It should be apparent that the described embodiments are only some embodiments of the present application, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any inventive step based on the embodiments in the present application, are within the scope of protection of the present application.

In this application, the terms "mounted," "connected," "secured," and the like are to be construed broadly unless otherwise expressly specified or limited. For example, the connection can be fixed, detachable or integrated; can be mechanically or electrically connected; they may be directly connected or indirectly connected through an intermediate member, or they may be connected through the inside of two elements, or they may be connected only through surface contact or through surface contact of an intermediate member. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as the case may be.

Furthermore, the terms "first," "second," and the like are used merely for distinguishing between descriptions and not intended to imply or imply a particular structure. The description of the terms "some embodiments," "other embodiments," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiments or examples is included in at least one embodiment or example of the application. In this application, the schematic representations of the terms used above are not necessarily intended to be the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the various embodiments or examples and features of the various embodiments or examples described in this application can be combined and combined by those skilled in the art without conflicting.

First embodiment

Referring to fig. 1, the present embodiment provides a projection device 10. By way of example, the projection device 10 includes at least one light guide system 20 and a light source device 400. The light source device 400 is arranged at the light entrance side of the light guide system 20 for sending out image light for incidence into the incoupling zone of said light guide system.

The light guide system 20 comprises an optical waveguide 100, an incoupling grating 200 and an outcoupling grating 300, wherein the incoupling grating 200 and the outcoupling grating 300 are both arranged on the optical waveguide 100.

Specifically, the optical waveguide 100 includes a first surface 110, a second surface 120 and an end surface 130, which are opposite to each other, the first surface 110 and the second surface 120 are substantially parallel to each other, and the optical waveguide 100 can transmit light. The incoupling grating 200 and the outcoupling grating 300 are both disposed on the second surface 120, i.e. the incoupling grating 200 and the outcoupling grating 300 are disposed on the same side surface of the optical waveguide 100. The end surface 130 is connected between the first surface 110 and the second surface 120 and is substantially perpendicular to the first surface 110 and the second surface 120. Wherein the optical waveguide 100 comprises a coupling-in region and a coupling-out region, at which the first surface 110 and the second surface 120 are formed at the same time.

The incoupling grating 200 is disposed in the incoupling region, and is configured to receive incident light with a single polarization state and couple the incident light into the optical waveguide 100, so that the incident light is totally reflected in the optical waveguide 100, and the totally reflected incident light propagates from the incoupling region to the outcoupling region. By changing the incident angle of the incident light upon the optical waveguide 100, the incident light satisfies the total reflection condition, and total reflection can be achieved within the optical waveguide 100. In this embodiment, the incoupling means is an incoupling grating.

Illustratively, the coupling grating can adopt a surface relief grating, the surface relief grating can be produced in batch by utilizing a nano-imprinting process, and the mass production type and the reliability of the coupling grating have obvious advantages compared with other gratings such as bragg gratings, and the response spectrum of the surface relief grating is not limited by processing materials, has a wider spectral response range and is more beneficial to forming stable and uniform illumination light. The incoupling grating may be a straight grating, an inclined grating, a blazed grating, or the like, which is not limited herein. Specifically, the incoupling grating is a one-dimensional grating and is provided with a grating vector k1, the outcoupling grating is provided with a grating vector k2 and a grating vector k3, wherein the grating vector k1, the grating vector k2 and the grating vector k3 form a closed-loop triangle, and the values of the grating vector k1, the grating vector k2 and the grating vector k3 satisfy that k2/k1 is more than or equal to 1 and less than or equal to 1.3,1 is more than or equal to 5363 and k3/k1 is more than or equal to 1.3.

Referring to fig. 2, a wave vector diagram of light propagation can be seen in fig. 2, and fig. 2 is a wave vector diagram of a single-layer waveguide in the light guide system shown in fig. 1. The wave vector diagram reflects the angular spectrum information of the image, the change of the grating to the angular spectrum information of the image and the range of the angular spectrum information of the light rays which can be carried by the optical waveguide plate. Wherein light of a specific wavelength may propagate within the waveguide plate along a left path and a right path. The wave vector of the incident light IN emitted from the light source 400 may exist IN one region BOX of the wave vector space defined by the initial wave vectors kx and ky. Each corner of the region BOX may represent a wave vector of light at a corner point of an input image, respectively.

When image information is transmitted by incident light, the angular spectrum information region formed in the wave vector diagram of the optical waveguide 100 is located between the first boundary BND1 and the second boundary BND2, and the angular spectrum information region contains complete image information, so that the loss of the finally transmitted image information can be avoided. Meanwhile, a plurality of angular spectrum information areas are not overlapped, so that the phenomenon that ghost/crosstalk occurs in finally transmitted image information to influence the final display effect is avoided.

BND1 denotes a first boundary for satisfying the Total Internal Reflection (TIR) criterion in the waveguide plate. BND2 denotes the second boundary of the largest wave vector in the waveguide plate 100. The maximum wave vector may be determined by the refractive index of the waveguide plate. I.e., the maximum value of the wavevector of the light emitted by the light source 400, depends on the refractive index of the single-layer waveguide. In the present embodiment, the refractive index of the optical waveguide 100 is 1.5 to 2.4, and exemplarily, the refractive index of the optical waveguide 100 may be 1.5 to 1.7, 1.7 to 1.9, 1.9 to 2.2, or 2.2 to 2.4, and the refractive index of the optical waveguide 100 may be 1.6, 1.8, 2.0, or 2.3, or any value between the two adjacent values. The refractive index of the optical waveguide 100 is too large or too small, which affects the angle at which the total reflection occurs, and thus the quality of the final image. Light can be waveguided in the slab only when its wave vector is in the region ZONE between the first boundary BND1 and the second boundary BND 2. If the wave vector of the light is outside the ZONE, the light may leak out of the waveguide plate or not propagate at all.

The paths of the wave vector v1 of the incident light in the coupling-in grating, the wave vector v2 in the optical waveguide 100 and the wave vector v3 of the coupling-out grating 300 in the wave vector diagram of the optical guide system are equilateral triangles, so that the propagation of the image light through the waveguide is ensured, no dispersion occurs, and the image light with a larger angle can be transmitted more stably.

In this embodiment, as shown in fig. 3, the incoupling grating is a one-dimensional grating, the incoupling grating has a grating vector k1, the outcoupling grating 300 is a two-dimensional grating formed by two one-dimensional even outcoupling gratings, grating vectors of the two one-dimensional outcoupling gratings are k2 and k3, respectively, and the grating vector k1, the grating vector k2, and the grating vector k3 form a closed loop. According to the waveguide theory, the equivalence relation between the input and the output of the waveguide can be ensured. Since the paths of the wave vector v1 of the incident light in the incoupling grating, the wave vector v2 in the optical waveguide 100 and the wave vector v3 in the outcoupling grating 300 in the wave vector diagram of the optical waveguide system are equilateral triangles, the incoupling grating and the outcoupling grating 300 are also configured to: the grating vector k1, the grating vector k2 and the grating vector k3 form a closed loop of an equilateral triangle. When the image is a non-equilateral triangle, as shown in fig. 4, and the corner information region contains incomplete image information, the transferred image information may be missing. Or as shown in fig. 5, causing ghosting/crosstalk of the finally transferred image information, affecting the final display effect.

For example, referring to FIG. 6, the out-coupling grating 300 may be a two-dimensional grating with a cylindrical array in top view. It further comprises an equivalent grating vector kx, the direction and magnitude of the grating vector kx of the out-coupling grating being the same as the grating vector k1 of the in-coupling grating. In this embodiment, the array structure can be equivalent to three one-dimensional gratings in different directions, as shown by the dotted lines, and its equivalent grating k vectors are k1, k2 and k3. In other embodiments, the array shape of the two-dimensional grating may also be a diamond shape, a triangle shape, a circle shape, or an oval shape, which is not limited herein. The depth of the outcoupling grating 300 may be 30nm to 200nm. Illustratively, the depth of the coupling-out grating 300 may be 30nm to 70nm, 70nm to 110nm, 110nm to 150nm, 150nm to 200nm, and specifically, the depth of the coupling-out grating 300 may be 60nm, 90nm, 130nm, 170nm or any value between the two adjacent values.

The light guide system provided by the embodiment adopts the light guide member 100 and the grating structure to emit the illumination light, the whole volume and the weight are small, and simultaneously, because the light is in the transmission process, the path in the wave vector diagram of the light guide system provided by the application is an equilateral triangle, the transmission of the image light through the waveguide is ensured, the dispersion cannot occur, and the image light with a larger angle can be transmitted more stably.

Second embodiment

The present embodiment provides a projection apparatus 10, which has substantially the same structure as the projection apparatus 10 in the first embodiment, and details of the same parts are not repeated, and reference may be made to relevant contents of the first embodiment, and only different parts are described below.

In this embodiment, referring to fig. 7, as an implementation manner, the coupling-out grating 300 is composed of two one-dimensional coupling-out gratings, wherein grating vectors of the two one-dimensional coupling-out gratings are k2 and k3, respectively. And the values of the raster vector k1, the raster vector k2 and the raster vector k3 meet the condition that k2/k1 is more than or equal to 1 and less than or equal to 1.3,1 is more than or equal to k3/k1 is more than or equal to 1.3.

In another embodiment, referring to fig. 8, the in-grating is a one-dimensional grating, the out-grating 300 is composed of a plurality of composite gratings, each of the composite gratings is composed of two one-dimensional out-gratings, and grating vectors of the two one-dimensional out-gratings are k2 and k3, respectively. And the values of the raster vector k1, the raster vector k2 and the raster vector k3 meet the condition that k2/k1 is more than or equal to 1 and less than or equal to 1.3,1 is more than or equal to k3/k1 is more than or equal to 1.3.

The structure of the outcoupling grating 300 proposed in this embodiment can also satisfy the equivalence relation of waveguide input and output. In other embodiments, the light-coupling grating 300 may be in other forms, and is not limited herein.

The light guide system provided by the embodiment adopts the light guide member 100 and the grating structure to emit the illumination light, the whole volume and the weight are small, and simultaneously, because the light is in the transmission process, the path in the wave vector diagram of the light guide system provided by the application is an equilateral triangle, the transmission of the image light through the waveguide is ensured, the dispersion cannot occur, and the image light with a larger angle can be transmitted more stably.

The above embodiments are only for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.

Claims (9)

1. A light guide system, characterized in that the light guide system comprises:

an optical waveguide comprising a coupling-in region and a coupling-out region;

the optical waveguide comprises a coupling-in grating arranged in the coupling-in area and a coupling-out grating arranged in the coupling-out area, wherein the coupling-in grating is used for receiving incident light and coupling the incident light into the optical waveguide so that the incident light is totally reflected in the optical waveguide and is coupled out from the coupling-out grating arranged in the coupling-out area, the coupling-in grating is a one-dimensional grating and is provided with a grating vector k1, the coupling-out grating is provided with a grating vector k2 and a grating vector k3, the grating vector k1, the grating vector k2 and the grating vector k3 form a closed-loop triangle, and the values of the grating vector k1, the grating vector k2 and the grating vector k3 satisfy that k2/k1 is more than or equal to 1 and less than or equal to 1.3,1 is more than or equal to k1 and less than or equal to 1.3.

2. The light guide system of claim 1, wherein the out-coupling grating is a two-dimensional grating further comprising an equivalent grating vector kx, the grating vector kx of the out-coupling grating being the same as the grating vector k1 of the in-coupling grating in direction and magnitude.

3. The light guide system of claim 1, wherein the outcoupling grating consists of two one-dimensional outcoupling gratings, wherein the grating vectors of the two one-dimensional outcoupling gratings are k2 and k3, respectively.

4. The light guide system of claim 1, wherein the outcoupling grating is composed of a plurality of composite gratings, each of the composite gratings is composed of two one-dimensional outcoupling gratings, the grating vectors of the two one-dimensional outcoupling gratings are k2 and k3, respectively.

5. The light guide system of claim 2, wherein the array of two-dimensional gratings has a diamond, triangular, circular or elliptical shape.

6. A light guide system according to claim 5, wherein the coupling-out grating has a depth of 30nm to 200nm.

7. A light guide system according to any one of claims 1 to 6, wherein the wave vector diagram of the light guide has a first boundary indicating that the total reflection range is satisfied in the light guide and a second boundary indicating that the maximum wave vector in the light guide is satisfied, the image information transmitted by the incident light, and the angular spectrum information region formed in the wave vector diagram of the light guide is located between the first boundary and the second boundary, and the angular spectrum information region contains the entire image information.

8. A light guide system according to any one of claims 1 to 7, wherein the refractive index of the light guide is in the range of 1.5 to 2.4.

9. A projection device, comprising:

one or more light guide systems as claimed in any one of claims 1-8; and

and the light source device is arranged at the light inlet side of the light guide system and is used for sending image light rays to be incident to the coupling-in area of the light guide system.

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