Disclosure of Invention
The embodiment of the invention provides an optical waveguide device and a near-to-eye display device, wherein the optical waveguide device can solve the display problems of blue arc, mirror stray light, external reflected stray light, limited viewing angle and the like of the existing array optical waveguide, improve the display effect of a display picture output by the optical waveguide device and reduce the manufacturing cost of the optical waveguide device.
In a first aspect, an embodiment of the present invention provides an optical waveguide device, including a waveguide sheet, where the waveguide sheet includes a coupling-in region and a coupling-out region, and a thickness of the coupling-in region is greater than a thickness of the coupling-out region;
The light emergent surface of the waveguide sheet is a first plane, the waveguide sheet further comprises a second plane opposite to the first plane, the coupling-in area and the coupling-out area are flush at one side of the second plane, and the coupling-in area protrudes towards one side far away from the second plane;
the coupling-in area comprises a coupling-in surface positioned on the side wall of the waveguide sheet, the coupling-out area comprises a plurality of coupling-out light-splitting surfaces which are arranged in parallel, the included angle between the coupling-in surface and the first direction is more than or equal to 68 degrees and less than or equal to 76 degrees, the included angle between the coupling-out light-splitting surface and the first direction is more than or equal to 34 degrees and less than or equal to 38 degrees, and the first direction is parallel to the light-out surface of the waveguide sheet and points to one side of the coupling-out area from the coupling-in area.
Optionally, the incident light is incident into the waveguide sheet from the coupling-in surface, and is coupled out from the coupling-out light splitting surfaces to human eyes after total reflection transmission in the waveguide sheet.
Optionally, when the incident light rays with different fields of view are incident into the waveguide sheet from the coupling-in surface and are transmitted in the waveguide sheet in a total reflection way, the light rays are connected end to end.
Optionally, the optical waveguide device further includes dielectric layers disposed on both surfaces of the waveguide sheet, and a refractive index of the dielectric layers is smaller than a refractive index of the waveguide sheet.
In a second aspect, an embodiment of the present invention provides an optical waveguide device, including a waveguide sheet, where the waveguide sheet includes a coupling-in area and a coupling-out area, the thickness of the coupling-in area is greater than that of the coupling-out area, the coupling-in area and the coupling-out area are flush at a side of a light-emitting surface of the waveguide sheet, and the coupling-in area protrudes toward a side away from the light-emitting surface of the waveguide sheet;
The coupling-in area comprises a coupling-in reflecting surface positioned on the side wall of the waveguide sheet or in the waveguide sheet, the coupling-out area comprises a plurality of coupling-out light-splitting surfaces which are arranged in parallel, the included angle between the coupling-in reflecting surface and the first direction is larger than or equal to 34 degrees and smaller than or equal to 38 degrees, the included angle between the coupling-out light-splitting surface and the second direction is larger than or equal to 34 degrees and smaller than or equal to 38 degrees, the first direction and the second direction are parallel to the light-out surface of the waveguide sheet, the first direction points to one side of the coupling-out area from the coupling-in area, and the second direction points to one side of the coupling-in area from the coupling-out area.
Optionally, the incident light is incident from the light-emitting surface side of the waveguide sheet, reflected by the coupling-in reflecting surface, and coupled out from the coupling-out light-splitting surfaces to human eyes after total reflection transmission in the waveguide sheet.
Optionally, the incident light rays with different fields of view are incident from one side of the light emitting surface of the waveguide sheet, and are all connected end to end when reflected by the coupling-in reflecting surface and then transmitted in the waveguide sheet in a total reflection way.
Optionally, the optical waveguide device further includes dielectric layers disposed on both surfaces of the waveguide sheet, and a refractive index of the dielectric layers is smaller than a refractive index of the waveguide sheet.
In a third aspect, an embodiment of the present invention provides an optical waveguide device, including a waveguide sheet including a first surface and a second surface disposed in parallel;
The waveguide sheet comprises a coupling-in area and a coupling-out area, the coupling-in area comprises a plurality of coupling-in light-splitting surfaces which are arranged in parallel, the coupling-out area comprises a plurality of coupling-out light-splitting surfaces which are arranged in parallel, the included angle between the coupling-in light-splitting surfaces and a first direction is larger than or equal to 34 degrees and smaller than or equal to 38 degrees, the included angle between the coupling-out light-splitting surfaces and a second direction is larger than or equal to 34 degrees and smaller than or equal to 38 degrees, the first direction and the second direction are parallel to the second surface, the first direction is directed to one side of the coupling-out area from the coupling-in area, and the second direction is directed to one side of the coupling-in area from the coupling-out area.
Optionally, the incident light is incident from the second surface, reflected by the plurality of coupling-in light-splitting surfaces, and coupled out from the plurality of coupling-out light-splitting surfaces to human eyes after total reflection transmission in the waveguide sheet.
Optionally, the optical waveguide device further includes a dielectric layer disposed on the first surface and the second surface, and a refractive index of the dielectric layer is smaller than a refractive index of the waveguide sheet.
In a fourth aspect, an embodiment of the present invention provides a near-eye display device, including a light engine and an optical waveguide device provided by any one of the embodiments of the present invention.
The optical waveguide device provided by the embodiment of the invention changes the propagation path of light in the optical waveguide sheet by adjusting the structures of the coupling-in area and the coupling-out area, so that the emergence angle of the coupling-out light of the central view field of the left and right image stray lights and the blue arc on the emergent surface of the optical waveguide sheet is increased, the entry of the left and right image stray lights and the blue arc into human eyes is avoided, the display effect of a display picture output by the optical waveguide device is improved, meanwhile, the refractive index of the optical waveguide sheet is larger than or equal to 1.52, the left and right image stray lights and the blue arc can be eliminated, the conventional glass with the refractive index of 1.52 has lower manufacturing cost, thereby reducing the manufacturing cost of the optical waveguide device, in addition, the optical waveguide device optimizes the working angle range of the coupling-out light splitting surface, reduces the design difficulty of the film system of the coupling-out light splitting surface, reduces the incident intensity of the external reflected stray lights, and improves the display effect of the display picture output by the optical waveguide device.
It should be understood that the description in this section is not intended to identify key or critical features of the embodiments of the invention or to delineate the scope of the invention. Other features of the present invention will become apparent from the description that follows.
Detailed Description
In order that those skilled in the art will better understand the present solution, a technical solution of an embodiment of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiment of the present invention, and it is apparent that the described embodiment is only a part of the embodiment of the present invention, not all the embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and the claims of the present invention and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the invention described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
The optical waveguide in the prior art has the problems of left image stray light, right image stray light, blue arc and external reflection stray light, so that the imaging quality is poor. In order to prevent the left image stray light, the right image stray light, the blue arc and the external reflected stray light from entering the human eye, the human eye needs to have no stray light in the moving range, the transverse field angle is 2 alpha0, the maximum eye moving length in the pupil expansion direction is H, the exit pupil distance is D, the pupil diameter of the human eye is generally 4mm, the stray light emitted from the optical waveguide needs not to enter the human eye, and the normal included angle alpha Stray light between the stray light emitted from the optical waveguide and the light guiding surface of the optical waveguide needs to be as follows:。
By way of example, assuming a human eye lateral field angle of 30 °, i.e., a0 of 15 °, D of 18mm, h of 8mm, a Stray light >39.5 ° can be derived from the above equation. I.e. when a Stray light >39.5 deg., stray light exiting the optical waveguide does not enter the human eye.
The reasons for the occurrence of left-image stray light, right-image stray light, blue arc and external reflected stray light in the optical waveguide of the related art will be described below, respectively. Fig. 1 is a schematic diagram of the positions of left image stray light, right image stray light, blue arc and display screen of an optical waveguide, fig. 2 is an optical path diagram of light rays of the right image stray light generated by the optical waveguide in the prior art, and in combination with fig. 1 and 2, the right image stray light is symmetrical to the display screen, so that a right edge central view ray of the display screen corresponds to a left edge central view ray of the right image stray light, an angle of normal of a light ray S1 propagating through total reflection in the optical waveguide and the light wave guiding out surface 110' is θ, an incident angle β of a light ray S2 coupled out from the right edge central view field of the display screen at the light wave guiding out surface 110', an exit angle α Right side of a light ray S2 coupled out from the right edge central view field of the display screen at the light guiding out surface 110' is α, an angle η of a light ray S3 and a coupling out light splitting surface 201' is η, an angle δ of a coupling out light ray S4 and the light guiding out surface is θ2, an angle β2 of an incident angle β of a light ray S5 coupled out from the left edge of the light guiding out surface 110', an angle β of a light wave guiding out surface is β, an angle β is β of a refractive angle β of a light guiding out surface is1, and an angle of a light wave coupling out from the left edge of the light splitting surface is a light ray is a light guiding out from a light source at a light receiving angle n.
,
,
,
,
,
,
The relation between alpha1 and alpha can be obtained in combination:
。
Fig. 3 is a light path diagram of a light ray of a left image stray light generated by a light waveguide in the prior art, and is shown in fig. 1 and 3, the left image stray light is symmetrical to a display screen, so that a left edge central view field light ray of the display screen corresponds to a right edge central view field light ray of the left image stray light, a normal angle between a light ray S6 propagating through total reflection in the light waveguide and the light wave guiding out light surface 110 'is θ, an incident angle of a left edge central view field coupled light ray S7 of the display screen at the light wave guiding out light surface 110' is β, an exit angle of a left edge central view field coupled light ray S7 of the display screen at the light wave guiding out light surface 110 'is α Left side, an angle between a light ray S8 and the light-splitting light surface 201' is η, an angle between the light-splitting light surface 201 'and the light wave guiding out light surface 110' is δ, a normal angle between a light ray S9 and the light wave guiding out light surface is θ2, an incident angle of a right edge central view field coupled light ray S10 at the light guiding out light surface 110 'is β2, an exit angle of a light ray S10 at the light guiding out light surface 110' is α2, and a refractive index of n is the light waveguide is:
,
,
,
,
,
,
the relation between alpha2 and alpha can be obtained in combination:
。
The blue arc is generated because the stray bottom light propagating in the optical waveguide cannot enter human eyes when the propagation direction of part of the stray bottom light cannot generate total reflection in the optical waveguide, and the red light in the stray bottom light has the smallest total reflection critical angle, the green light and the Lan Guangquan reflection critical angle because the refractive index of the red light corresponding to the waveguide is lower than that of the blue light. The red light therefore first disappears at the critical point, followed by the green light and finally by the blue light, so that the blue arc actually appears to be two arced narrow bands consisting of blue and cyan. Let the blue arc center field angle be α Blue arc, the expression of α Blue arc can be derived:
。
From the above equation, the central field angle of the blue arc is only related to the angle of the coupling-out light-splitting surface and the refractive index of the optical waveguide, and the higher the refractive index of the optical waveguide, the larger the central field angle of the blue arc, and the further the blue arc is from the normal display screen.
It will be appreciated that half of the maximum field angle supported in the pupil expansion direction of the coupling-out facet cannot exceed the exit angles α1 and α2 of the left and right specular parasitic lights, which would otherwise be contained in the field angles, so that the maximum field angle supported in the pupil expansion direction is maximum when the exit angles α1 and α2 of the left and right specular parasitic lights are equal. Illustratively, α1 and α2 are equal, where the exit angles of the coupled-out light rays of the left and right edge central fields of view of the display screen should be equal, i.e., α Left side=α Right side, and the coupled-out light splitting plane angle δ is calculated to be about 25.7. When the refractive index n=2 of the optical waveguide, the maximum angle of view supported in the coupling-out spectroscopic surface pupil expansion direction is about 52.9. Whereas α1 and α2 are 38.8. Since α Stray light >39.5 ° is not satisfied, left and right specular stray light enters human eyes, resulting in a decrease in display effect.
In addition, the optical waveguide in the prior art has the problem of external reflection stray light, fig. 4 is a light path diagram of the external reflection stray light in the optical waveguide in the prior art, and referring to fig. 4, a dashed line in fig. 4 is a propagation path of the external reflection stray light, and external light is refracted from the surface of the optical waveguide and enters the optical waveguide, and then is reflected at the coupling-out light-splitting surface 201', and is coupled out of the optical waveguide to form the external reflection stray light.
In order to solve the problem that the imaging quality is poor due to the reflection of left and right image stray light, blue arc and external reflected stray light into human eyes through the optical waveguide, the embodiment of the invention provides an optical waveguide device, fig. 5 is a schematic structural diagram of the optical waveguide device provided by the embodiment of the invention, referring to fig. 5, the optical waveguide device comprises a waveguide sheet, the waveguide sheet comprises a coupling-in area 100 and a coupling-out area 200, the thickness of the coupling-in area 100 is greater than the thickness of the coupling-out area 200, the light-out surface 110 of the waveguide sheet is a first plane, the waveguide sheet further comprises a second plane 120 opposite to the first plane, the coupling-in area 100 and the coupling-out area 200 are flush on one side of the second plane 120, the coupling-in area 100 protrudes towards one side away from the second plane 120, the coupling-in area 100 comprises a coupling-in surface 101 positioned on the side wall of the waveguide sheet, the coupling-out area 200 comprises a plurality of coupling-out split light surfaces 201 arranged in parallel, the coupling-in angle between the coupling-in surface 101 and the first direction X is greater than or equal to 68 ° and less than or equal to 76 °, the coupling-out light-split light surface 201 and the first direction X is greater than or equal to 34 ° and is parallel to the coupling-out light-out area 200 and is directed to one side of the waveguide sheet from the first plane 110.
Fig. 6 is a light path diagram of a right image stray light in a waveguide sheet according to an embodiment of the present invention, and as shown in fig. 2, 5 and 6, a propagation path of a light ray in the waveguide sheet according to an embodiment of the present invention is different from a propagation path of a waveguide sheet according to the prior art, a normal angle between a light ray S11 totally reflected in the waveguide sheet and a light exit surface 110 of the waveguide sheet is θ, an incident angle of a right edge center view field coupled light ray S12 of a display screen on the light exit surface 110 of the waveguide sheet is β, an exit angle of a right edge center view field coupled light ray S12 of the display screen on the light exit surface 110 of the waveguide sheet is α Right side, an angle between a coupled light exit surface 201 and the light exit surface 110 of the waveguide sheet is δ, an angle between a left edge center view field coupled light ray S13 of the right image stray light and the coupled light exit surface 201 is η, an incident angle of a left edge center view field coupled light ray S13 of the right image stray light on the light exit surface 110 of the waveguide sheet is β2, an exit angle of a left edge center view coupled light ray S13 on the light exit surface 110 of the light exit surface of the waveguide sheet is α1, and a refractive index of the waveguide sheet is n, which can be obtained:
,
,
,
,
,
The relation between alpha1 and alpha can be obtained in combination:
。
Fig. 7 is a light path diagram of left image stray light in a waveguide sheet provided by the embodiment of the present invention, and referring to fig. 3 and 7, the propagation path of light in the waveguide sheet provided by the embodiment of the present invention is different from that of the waveguide sheet in the prior art, the angle of incidence θ between the light ray S14 totally reflected in the waveguide sheet and the light exit surface 110 of the waveguide sheet is set to be θ, the angle of incidence β of the light ray S15 coupled to the left edge center field of view of the display screen on the light exit surface 110 of the waveguide sheet is set to be β, the angle of emergence α Left side of the light ray S15 coupled to the left edge center field of view of the display screen on the light exit surface 110 of the waveguide sheet is set to be δ, the angle of incidence η between the light ray S16 and the light exit surface 201 of the coupled to the light exit surface 110 of the waveguide sheet is set to be η, the angle of incidence β2 of the light ray S17 coupled to the right edge center field of view of the left image stray light on the light exit surface 110 of the waveguide sheet is set to be α2, and the refractive index of the waveguide sheet is n, the following relationship can be obtained:
,
,
,
,
,
the relation between alpha2 and alpha can be obtained in combination:
。
Let α1=α2 be the maximum horizontal angle of view of the display, wherein α Left side=α Right side is calculated to obtain the angle δ=36 between the coupling-out light-splitting plane 201 and the light-emitting plane 110 of the waveguide sheet. When the refractive index n=2 of the waveguide sheet, the lateral viewing angle of the display screen is 76.3 °, which is far greater than 52.9 in the prior art. A lateral viewing angle of a display screen of (a). When the refractive index n of the waveguide sheet was 1.52, α1 and α2 were calculated to be 42.1. The calculation formula of the blue arc center field angle is consistent with that in the prior art, and alpha Blue arc can be obtained to be 51.2. It can be seen that both α1、α2 and α Blue arc are greater than 39.5. That is, both left and right mirror stray light and blue arc cannot enter human eyes, and the waveguide sheet structure provided by the embodiment of the invention can prevent the left and right mirror stray light and blue arc from entering human eyes when the refractive index n of the waveguide sheet is more than or equal to 1.52.
Fig. 8 is a light path diagram of external reflection stray light in a waveguide sheet according to an embodiment of the present invention, and a dashed line in fig. 8 is a propagation path of the external reflection stray light, and, as shown in fig. 4 and 8, the external reflection stray light in the waveguide sheet of the prior art can enter an eye only by being reflected once on the coupling-out light-splitting surface 201', and the intensity of the external reflection stray light observed by the eye is typically 10% to 30% of the external incident light. The external reflection stray light can enter the human eye after being reflected by the light-emitting and splitting surface 201 and totally reflected by the waveguide surface at least twice in the waveguide sheet provided by the embodiment of the invention, and the process at least comprises one large-angle reflection, and the reflection rate of the large-angle reflection in the waveguide sheet can be controlled to be below 5% by designing the light-emitting and splitting mask system, so that the intensity of the external reflection stray light can be attenuated to be negligible by the waveguide sheet provided by the embodiment of the invention. Fig. 9 is a graph of the relationship between the reflectivity of the film system of the coupling-out light-splitting surface and the incident angle in the prior art, and fig. 10 is a graph of the relationship between the reflectivity of the film system of the coupling-out light-splitting surface and the incident angle in the prior art, and in combination with fig. 9 and 10, the film system needs to have a certain reflectivity in a specific small angle range to couple out the incident light to form a display screen, and in addition, needs to have low reflectivity in a large angle range to alleviate the mirror image stray light problem, in the prior art, the included angle between the coupling-out light-splitting surface and the waveguide surface is generally 25. About, the prior art film system has a small angle operating angle range of typically 15. To 37. Between, the large operating angle range is generally 66. To 88. Between them. Because of the inherent characteristics of the film system, the reflectivity of the film system can be increased sharply when the incident angle is larger than 83 degrees, which brings great difficulty to the design of the film coating. In the waveguide sheet provided by the embodiment of the present invention, the angle between the coupling-out light-splitting surface 201 and the light-out surface 110 of the waveguide sheet is greater than or equal to 34 ° and less than or equal to 38 °, which makes the working angle range of the film system in the embodiment of the present invention generally 25 °. To 47. Between, the large operating angle range is generally 66. To 83. The problem that the design difficulty is increased because the incident reflectivity of the film system is increased sharply is solved, the S light reflectivity of the coupling-out light-splitting film system of the embodiment of the invention tends to increase in the range of 25-47 degrees from small angle, the P light reflectivity tends to decrease in the range of 25-47 degrees from small angle, and the S light reflectivity and the P light reflectivity are as low as possible in the range of 61-83 degrees from large angle, so that the incident intensity of external reflected stray light can be reduced to less than 1% of external incident light.
The optical waveguide device provided by the embodiment of the invention changes the propagation path of light in the optical waveguide sheet by adjusting the structures of the coupling-in area and the coupling-out area, so that the emergence angle of the coupling-out light of the central view field of the left and right image stray lights and the blue arc on the emergent surface of the optical waveguide sheet is increased, the entry of the left and right image stray lights and the blue arc into human eyes is avoided, the display effect of a display picture output by the optical waveguide device is improved, meanwhile, the refractive index of the optical waveguide sheet is larger than or equal to 1.52, the left and right image stray lights and the blue arc can be eliminated, the conventional glass with the refractive index of 1.52 has lower manufacturing cost, thereby reducing the manufacturing cost of the optical waveguide device, in addition, the optical waveguide device optimizes the working angle range of the coupling-out light splitting surface, reduces the design difficulty of the film system of the coupling-out light splitting surface, reduces the incident intensity of the external reflected stray lights, and improves the display effect of the display picture output by the optical waveguide device.
Fig. 11 is a light path diagram of an incident light beam propagating in a waveguide sheet according to an embodiment of the present invention, and referring to fig. 5 and 11, the incident light beam is incident into the waveguide sheet from the coupling-in surface 101, and is coupled out from the plurality of coupling-out light splitting surfaces 201 to the human eye after total reflection transmission in the waveguide sheet. The coupling-out beam-splitting surface 201 can reflect part of the incident light and transmit the rest of the incident light. The plurality of coupling-out facets 201 may enable pupil expansion of the incident light rays in the first direction X.
Fig. 12 is a light path diagram of coupling incident light rays with different fields of view into a waveguide sheet according to an embodiment of the present invention, wherein broken lines represent the incident light rays, and referring to fig. 12, the incident light rays with different fields of view are all connected end to end when they are incident from the coupling-in surface 101 into the waveguide sheet for total reflection transmission in the waveguide sheet. Fig. 13 is a light path diagram of incident light rays with different angles propagating in a waveguide sheet without a convex structure, and in combination with fig. 12 and fig. 13, since the step size of total reflection of the incident light rays in the waveguide sheet is large, if the coupling-in structure of the waveguide sheet does not include the convex structure, the light rays are discontinuous, and as shown in fig. 13, discontinuous dark bands are generated in the coupling-out area, which affects the brightness uniformity of the display screen. The convex structure in the waveguide sheet provided by the embodiment of the invention enables incident light rays to be connected end to end in the waveguide sheet, and improves the uniformity of a display picture.
Optionally, the optical waveguide device further includes dielectric layers disposed on both surfaces of the waveguide sheet, and a refractive index of the dielectric layers is smaller than a refractive index of the waveguide sheet. The dielectric layers are coated on the two surfaces of the waveguide sheet through a coating or laminating process, and the thickness of the dielectric layers is larger than 1 mu m. Illustratively, the material of the dielectric layer includes glue, resin, silica gel or dielectric material.
Based on the same inventive concept, an embodiment of the present invention provides an optical waveguide device, fig. 14 is a schematic structural diagram of another optical waveguide device provided by the embodiment of the present invention, referring to fig. 14, the optical waveguide device includes a waveguide sheet, the waveguide sheet includes a coupling-in area 300 and a coupling-out area 400, the coupling-in area 300 has a thickness greater than that of the coupling-out area 400, the coupling-in area 300 and the coupling-out area 400 are flush at one side of the light-out surface 310 of the waveguide sheet, the coupling-in area 300 protrudes toward one side away from the light-out surface 310 of the waveguide sheet, the coupling-in area 300 includes a coupling-in reflective surface 301 located on a side wall of the waveguide sheet or in the waveguide sheet, the coupling-out area 400 includes a plurality of coupling-out light-splitting surfaces 401 disposed in parallel, an included angle between the coupling-in reflective surface 301 and the first direction X is greater than or equal to 34 ° and less than or equal to 38 °, the coupling-out light-splitting surfaces 401 and the second direction Y are both parallel to the light-out surface of the waveguide sheet, the first direction X and the coupling-out direction X is directed from the coupling-out area 400 to one side.
As shown in fig. 5 and 14, the thickness of the bump structure of the optical waveguide device in fig. 14 is smaller, and at the same time, the left image stray light, the right image stray light, the blue arc and the external reflected stray light can be prevented from entering the human eye.
Fig. 15 is a light path diagram of an incident light beam propagating in another waveguide sheet according to an embodiment of the present invention, referring to fig. 15, the incident light beam is incident from a light-emitting surface 310 side of the waveguide sheet, reflected by the coupling-in reflecting surface 301, and coupled out from the coupling-out light-splitting surfaces 401 to the human eye after total reflection transmission in the waveguide sheet.
Fig. 16 is a light path diagram of the incident light rays with different fields of view propagating in another waveguide sheet, wherein the dashed lines represent the incident light rays, and referring to fig. 16, the incident light rays with different fields of view are incident from one side of the light emitting surface 310 of the waveguide sheet, and are all connected end to end when reflected by the coupling-in reflection surface 301 and then transmitted in total reflection in the waveguide sheet.
Optionally, the optical waveguide device further includes dielectric layers disposed on both surfaces of the waveguide sheet, and a refractive index of the dielectric layers is smaller than a refractive index of the waveguide sheet. The dielectric layers are coated on the two surfaces of the waveguide sheet through a coating or laminating process, and the thickness of the dielectric layers is larger than 1 mu m. Illustratively, the material of the dielectric layer includes glue, resin, silica gel or dielectric material.
Based on the same inventive concept, an embodiment of the present invention provides an optical waveguide device, and fig. 17 is a schematic structural diagram of another optical waveguide device provided by the embodiment of the present invention, referring to fig. 17, the optical waveguide device includes a waveguide sheet, the waveguide sheet includes a first surface 510 and a second surface 520 disposed in parallel, the waveguide sheet includes a coupling-in region 500 and a coupling-out region 600, the coupling-in region 500 includes a plurality of coupling-in light splitting surfaces 501 disposed in parallel, the coupling-out region 600 includes a plurality of coupling-out light splitting surfaces 601 disposed in parallel, an included angle between the coupling-in light splitting surfaces 501 and a first direction X is greater than or equal to 34 ° and less than or equal to 38 °, an included angle between the coupling-out light splitting surfaces 601 and a second direction Y is greater than or equal to 34 ° and less than or equal to 38 °, the first direction X and the second direction Y are both parallel to the second surface 520, the first direction X is directed to one side of the coupling-out region 600 from the coupling-in region 500.
Fig. 18 is a light path diagram of an incident light beam propagating in another waveguide sheet according to an embodiment of the present invention, and referring to fig. 12, 13 and 18, the incident light beam is incident from the second surface 520, reflected by the plurality of coupling-in light splitting surfaces 501, and coupled out from the plurality of coupling-out light splitting surfaces 601 to the human eye after being transmitted by total internal reflection in the waveguide sheet. In fig. 13, after light enters the waveguide sheet without the protruding structure, a discontinuous dark band is generated in the coupling-out area, but the waveguide sheet provided in the embodiment of the invention includes a plurality of coupling-in light splitting surfaces 501, and the incident light coupled from the plurality of coupling-in light splitting surfaces 501 can be complementary, so that the problem of uneven distribution of the incident light in space is eliminated.
Optionally, the optical waveguide device further includes a dielectric layer (not shown in fig. 17) disposed on the first surface 510 and the second surface 520, the dielectric layer having a refractive index less than the refractive index of the waveguide sheet. The dielectric layer is coated on the first surface 510 and the second surface 520 by a plating or bonding process, and the thickness of the dielectric layer is greater than 1 μm. Illustratively, the material of the dielectric layer includes glue, resin, silica gel or dielectric material.
Fig. 19 is a schematic structural diagram of a two-dimensional array waveguide according to an embodiment of the present invention, and the coupling-in structure and the coupling-out structure of the two-dimensional array waveguide are similar to those of the optical waveguide device in fig. 5, 14 or 17, as shown in fig. 5, 14, 17 and 19.
Based on the same inventive concept, the embodiment of the invention provides a near-eye display device, which comprises a light machine and the optical waveguide device provided by any embodiment of the invention.
Since the near-eye display device includes the optical waveguide device provided by any of the embodiments of the present invention, the near-eye display device has the same or corresponding technical effects as the optical waveguide device.
The above embodiments do not limit the scope of the present invention. It will be apparent to those skilled in the art that various modifications, combinations, sub-combinations and alternatives are possible, depending on design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of the present invention.