Optical waveguide structure

Abstract

The utility model provides an optical waveguide structure. The optical waveguide structure comprises: a waveguide plate, on which at least a coupling-in portion and a coupling-out portion are arranged; an optical path plate, on which at least one side surface of the waveguide plate is arranged an optical path plate, the refractive index of the optical path plate is less than the refractive index of the waveguide plate, and the difference in refractive index between the waveguide plate and the optical path plate is less than or equal to 1, and the optical path plate is used to receive the light transmitted in the waveguide plate and transmit the light in the optical path plate. The utility model solves the problem of poor uniformity of different viewing fields in the optical waveguide structure in the prior art.

Description

Technical Field

[0001] The utility model relates to the technical field of optical display equipment, in particular to an optical waveguide structure. Background Art

[0002] With the continuous development of the optical display field, AR wearable devices have gradually attracted the attention of the public due to their portability, small size, and rich display effects combining virtuality and reality. There are many types of AR wearable devices, such as AR glasses.

[0003] At present, the optical waveguide structure is a key component of AR glasses, and its performance determines the final presentation effect of AR glasses. The main function of the optical waveguide structure is to expand the pupil and transmit light. One-dimensional or two-dimensional pupil expansion is achieved through multiple total reflections of light in the optical waveguide structure. Therefore, total reflection is the most basic principle and condition for the optical waveguide structure to realize its function. The light field emitted by the optical machine has a certain field of view angle, that is, the output light field of the optical machine contains light at different angles, which directly leads to a large difference in the incident angle of the light on the optical waveguide structure, resulting in different step lengths of total reflection of the light in the optical waveguide structure. Different light propagation step lengths will lead to different uniformity of different fields of view, affecting the display uniformity of the optical waveguide structure.

[0004] That is to say, the optical waveguide structure in the prior art has the problem of poor uniformity in different viewing fields. Utility Model Content

[0005] The main purpose of the utility model is to provide an optical waveguide structure to solve the problem of poor uniformity of different viewing fields in the optical waveguide structure in the prior art.

[0006] In order to achieve the above-mentioned purpose, the utility model provides an optical waveguide structure, including: a waveguide plate, on which at least a coupling-in portion and a coupling-out portion are arranged; an optical path plate, on which at least one side surface of the waveguide plate is arranged an optical path plate, the refractive index of the optical path plate is smaller than the refractive index of the waveguide plate, and the difference in refractive index between the waveguide plate and the optical path plate is less than or equal to 1, and the optical path plate is used to receive the light transmitted in the waveguide plate and transmit the light in the optical path plate.

[0007] Furthermore, the difference in refractive index between the waveguide plate and the optical path plate is greater than 0.2 and less than 0.7.

[0008] Furthermore, the optical path plate is one or more than one piece. When there are multiple optical path plates, multiple optical path plates are arranged on only one surface of the waveguide plate, and the multiple optical path plates are stacked and arranged in a direction away from the waveguide plate; or optical path plates are arranged on both sides of the waveguide plate, and the number of optical path plates on the same side of the waveguide plate is one or more.

[0009] Furthermore, the angle α at which the light in the waveguide is incident on the surface of the waveguide, the refractive index nwg The refractive index n of the optical path sheet satisfies:

[0010] Furthermore, the difference in thickness between two different positions of the optical path sheet is less than or equal to 10 um; and / or the thickness of the optical path sheet is greater than 0.05 mm and less than 2 mm.

[0011] Furthermore, the thickness of the waveguide plate is greater than 0.2 mm and less than 2 mm; and / or the refractive index of the waveguide plate is greater than 1.3 and less than 2.2.

[0012] Furthermore, the optical path sheet is a glass sheet or a resin sheet.

[0013] Furthermore, the optical path plate and the waveguide plate are integrally formed or the optical path plate and the waveguide plate are glued together by a glue structure, and the absolute value of the refractive index difference between the glue structure and the optical path plate is less than 0.01, or the absolute value of the refractive index difference between the glue structure and the waveguide plate is less than 0.01.

[0014] Furthermore, the projection area of ​​the optical path plate on the waveguide plate is less than or equal to the surface area of ​​the waveguide plate on which it is located, the out-coupling portion is located on one side surface of the waveguide plate, the optical path plate and the out-coupling portion are located on the same side or different sides of the waveguide plate, and the projection of the optical path plate on the waveguide plate at least partially covers the projection of the out-coupling portion on the waveguide plate.

[0015] Furthermore, the coupling-in part is used to couple the light projected by the external optical machine into the waveguide plate, and the coupling-in part includes a coupling-in port and a reflecting surface, a prism, and a diffraction element that cooperate with each other.

[0016] By applying the technical solution of the utility model, the optical waveguide structure includes a waveguide plate and an optical path plate, the waveguide plate is provided with at least a coupling-in portion and a coupling-out portion; the optical path plate is provided on at least one side surface of the waveguide plate, the refractive index of the optical path plate is smaller than the refractive index of the waveguide plate, and the difference in refractive index between the waveguide plate and the optical path plate is less than or equal to 1, and the optical path plate is used to receive the light transmitted in the waveguide plate and transmit the light in the optical path plate.

[0017] By arranging a coupling part and an out-coupling part on the waveguide plate, the coupling part can couple the light emitted by the external optical machine into the waveguide plate, so that the light is fully reflected and transmitted in the waveguide plate, and then coupled out through the out-coupling part for imaging display, so as to ensure the reliability of light transmission. By arranging an optical path plate on the surface of the waveguide plate, and planning the refractive index of the optical path plate to be less than the refractive index of the waveguide plate, and further arranging the difference between the refractive index of the waveguide plate and the optical path plate to be less than or equal to 1, the light that is fully reflected and transmitted in the waveguide plate can enter the optical path plate through the surface when it is incident on the side surface of the waveguide plate where the optical path plate is arranged, so that the light is transmitted in the optical path plate, and the light with a small angle can enter the optical path plate for transmission, increasing the total reflection step, reducing the difference in optical path under different incident field angles, achieving the improvement of uniformity of different fields of view, and greatly improving the imaging quality of the optical waveguide structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings constituting part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0019] Figure 1 The light paths of the waveguide sheet incident at different angles in the prior art are shown;

[0020] Figure 2 The optical path diagram of the optical waveguide structure of the first embodiment of the utility model is shown;

[0021] Figure 3 Another optical path diagram of the optical waveguide structure of the first embodiment of the utility model is shown;

[0022] Figure 4 Shows Figure 2 A graph of the field of view angle and step length of the optical waveguide structure in FIG.

[0023] Figure 5 It shows the optical path diagram of the optical waveguide structure of the second embodiment of the utility model;

[0024] Figure 6 Another optical path diagram of the optical waveguide structure of the second embodiment of the utility model is shown;

[0025] Figure 7 Another optical path diagram of the optical waveguide structure of the second embodiment of the utility model is shown;

[0026] Figure 8 Shows Figure 5 Graph of field of view angle and step size for the optical waveguide structure in FIG.

[0027] The above drawings include the following reference numerals:

[0028] 10. Waveguide plate; 11. Coupling port; 12. Reflection surface; 20. Optical path plate; 21. First optical path plate; 22. Second optical path plate. DETAILED DESCRIPTION

[0029] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present utility model will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0030] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs.

[0031] In the present invention, unless otherwise specified, the directional words used, such as "up, down, top, bottom", usually refer to the directions shown in the drawings, or to the components themselves in the vertical, perpendicular or gravity directions; similarly, for ease of understanding and description, "inside and outside" refer to the inside and outside relative to the outline of each component itself, but the above-mentioned directional words are not used to limit the present invention.

[0032] In order to solve the problem of poor uniformity of different viewing fields in the optical waveguide structure in the prior art, the utility model provides an optical waveguide structure.

[0033] like Figures 1 to 8 As shown, the optical waveguide structure includes a waveguide plate 10 and an optical path plate 20. The waveguide plate 10 is provided with at least a coupling-in portion and a coupling-out portion. The optical path plate 20 is provided on at least one side surface of the waveguide plate 10. The refractive index of the optical path plate 20 is smaller than the refractive index of the waveguide plate 10, and the difference in refractive index between the waveguide plate 10 and the optical path plate 20 is less than or equal to 1. The optical path plate 20 is used to receive the light transmitted in the waveguide plate 10 and transmit the light in the optical path plate 20.

[0034] By arranging a coupling part and an out-coupling part on the waveguide plate 10, the coupling part can couple the light emitted by the external optical machine into the waveguide plate 10, so that the light is totally reflected and transmitted in the waveguide plate 10, and then coupled out through the out-coupling part for imaging display, so as to ensure the reliability of light transmission. By arranging an optical path plate 20 on the surface of the waveguide plate 10, and planning the refractive index of the optical path plate 20 to be less than the refractive index of the waveguide plate 10, and further arranging the difference between the refractive indexes of the waveguide plate 10 and the optical path plate 20 to be less than or equal to 1, when the light that is totally reflected and transmitted in the waveguide plate 10 is incident on a side surface of the waveguide plate 10 where the optical path plate 20 is arranged, it can enter the optical path plate 20 through the surface, so that the light is transmitted in the optical path plate 20, and the light of small angle can enter the optical path plate 20 for transmission, increasing the total reflection step, reducing the difference in optical path under different incident field angles, achieving the improvement of uniformity of different fields of view, and greatly improving the imaging quality of the optical waveguide structure.

[0035] Preferably, the difference in refractive index between the waveguide plate 10 and the optical path plate 20 is greater than 0.2 and less than 0.7. By reasonably constraining the difference in refractive index between the waveguide plate 10 and the optical path plate 20, it is helpful to ensure the incident angle screening function of the optical path plate 20, so that the step length difference of different incident field angles is reduced, which is helpful to reduce the uniformity difference of different fields of view and improve the display effect.

[0036] In different embodiments of the present application, the optical path plate 20 is overlapped with the waveguide plate 10 to form a whole that fully reflects and transmits light. The optical path plate 20 is one or more pieces. When the optical path plate 20 is one piece, the optical path plate 20 is arranged on the light incident side of the waveguide plate 10 or on the light emitting side of the waveguide plate 10; when the optical path plate 20 is multiple pieces, multiple optical path plates 20 are arranged on only one side surface of the waveguide plate 10, that is, multiple optical path plates 20 are all arranged on one side surface of the waveguide plate 10. Specifically, multiple optical path plates 20 are all arranged on the light incident side or the light emitting side of the waveguide plate 10, and multiple optical path plates 20 are stacked in a direction away from the waveguide plate 10; or optical path plates 20 are arranged on both side surfaces of the waveguide plate 10, and the number of optical path plates 20 on the same side of the waveguide plate 10 is one or more pieces. By rationally selecting the number of optical path sheets 20 and planning the location of the optical path sheets 20 , it is advantageous for the optical path sheet 20 to achieve optical path compensation for different fields of view, thereby increasing the versatility of the optical path sheet 20 .

[0037] Specifically, the angle α at which the light in the waveguide sheet 10 is incident on the surface of the waveguide sheet 10 and the refractive index n of the waveguide sheet 10 are wg The refractive index n of the optical path plate 20 satisfies: Specifically, the surface of the waveguide sheet 10 at the angle α at which the light in the waveguide sheet 10 is incident on the surface of the waveguide sheet 10 is actually the surface where the optical path sheet 20 is located. By constraining this relationship, it is helpful to ensure that the incident light with the angle α can stably enter the optical path sheet 20 for total reflection transmission, thereby ensuring the reliability of the use of the optical path sheet 20. In other words, this relationship is the condition for the light to enter the optical path sheet 20.

[0038] Specifically, the thickness difference between two different positions of the optical path plate 20 is less than or equal to 10um. Specifically, the thickness difference between any two different positions of the optical path plate 20 is less than or equal to 10um. This setting is conducive to ensuring the thickness consistency of the optical path plate 20, ensuring that no additional optical path difference is introduced and the angle of the light is not changed after transmission through the waveguide plate 10, thereby avoiding the risk of image quality degradation due to field of view crosstalk.

[0039] Specifically, the thickness of the waveguide sheet 10 is greater than 0.2 mm and less than 2 mm, the refractive index of the waveguide sheet 10 is greater than 1.3 and less than 2.2, and the thickness of the optical path sheet 20 is greater than 0.05 mm and less than 2 mm. By selecting a waveguide sheet 10 with a suitable thickness and refractive index and an optical path sheet 20 with a suitable thickness, it is beneficial to apply the optical waveguide structure in AR glasses, ensuring that the optical waveguide structure is light and thin.

[0040] In the present application, the optical path sheet 20 is a solid glass sheet or a resin sheet. In an optional embodiment of the present application, the optical path sheet 20 is integrally formed with the waveguide sheet 10. Specifically, the material of the optical path sheet 20 can be photosensitive glue or thermosensitive curing glue, which is evenly coated on the surface of the waveguide sheet 10 and then cured by light or heat curing, so that the optical path sheet 20 and the waveguide sheet 10 form a whole. In this way, the optical path sheet 20 is directly formed on the waveguide sheet 10, eliminating the lamination process, and no longer requiring an additional glue structure, so that fewer variables are introduced. In another optional embodiment of the present application, the optical path plate 20 may be directly overlapped with the waveguide plate 10 without using a glue structure, or the optical path plate 20 and the waveguide plate 10 may be glued together using a glue structure, and the absolute value of the refractive index difference between the glue structure and the optical path plate 20 is less than 0.01, or the absolute value of the refractive index difference between the glue structure and the waveguide plate 10 is less than 0.01, that is, the refractive index of the glue structure needs to be close to that of one of the waveguide plate 10 and the optical path plate 20, so as to reduce the optical path deviation caused by the introduction of the glue structure.

[0041] Specifically, the projected area of ​​the optical path plate 20 on the waveguide plate 10 is less than or equal to the surface area of ​​the waveguide plate 10 where it is located, that is, the size of the optical path plate 20 is not larger than the size of the waveguide plate 10, so that the optical path plate 20 does not completely cover the surface of one side of the waveguide plate 10 where it is located. In this way, part of the light with a smaller incident angle in the waveguide plate 10 with a high refractive index can enter the optical path plate 20 with a low refractive index and continue to propagate, and is totally reflected at the interface between the optical path plate 20 and the air, and then returns from the optical path plate 20 to the waveguide plate 10, the optical path of this part of the light is increased, and the step length of the total reflection is also increased accordingly, so as to achieve the purpose of reducing the difference with the total reflection step length of the light with a large incident angle.

[0042] In a specific embodiment of the present application, the coupling part is used to couple the light projected by the external optical machine into the waveguide plate 10, and the coupling part is used to couple the light transmitted in the waveguide plate 10 out to the human eye for imaging. The coupling part includes a coupling port 11 and a reflective surface 12 that cooperate with each other, a prism, and a diffraction element. Specifically, in one embodiment of the present application, the coupling part is a coupling port 11 and a reflective surface 12 that cooperate with each other, and the coupling part is a prism. Figure 1 , the coupling port 11 is located on the light incident surface of the waveguide plate 10, the reflection surface 12 is arranged obliquely to the surface where the coupling port 11 is located, and the angle between the reflection surface 12 and the surface where the coupling port 11 is located is an acute angle, and the light emitted by the optical machine is incident on the reflection surface 12 from the coupling port 11, and is reflected by the reflection surface 12 and transmitted by total reflection in the waveguide plate 10. In another embodiment of the present application, not shown in the figure, the coupling part is a prism, and the prism is specifically a triangular prism. The triangular prism is located on one side surface of the waveguide plate 10, and the projections of the triangular prism and the coupling part on the waveguide plate 10 are arranged at intervals, and the coupling of the light emitted by the optical machine is achieved through the triangular prism. In another embodiment of the present application, not shown in the figure, the coupling part is a diffraction element, which can be specifically a coupling grating. In this case, the coupling grating and the coupling part are arranged at intervals on one side surface of the waveguide plate 10, or the coupling grating and the coupling part are respectively located on different surfaces of the waveguide plate 10, and the projections of the two on the waveguide plate 10 are arranged at intervals. Such an arrangement enables the optical waveguide structure of the present application to adapt to different coupling-in parts, thus ensuring versatility and application range.

[0043] Optionally, the coupling-out portion of the present application is a coupling-out grating, and the coupling-out grating is a one-dimensional grating or a two-dimensional grating. When the coupling-out grating is a one-dimensional grating, the optical waveguide structure further includes a turning grating, and the turning grating is used to receive the light from the coupling-in portion and perform one-dimensional or two-dimensional pupil expansion, and then transmit it to the coupling-out grating, and emit it from the coupling-out grating; at this time, the projection of the optical path sheet 20 on the waveguide sheet 10 at least covers the turning grating and the coupling-out grating. When the coupling-out grating is a two-dimensional grating, the turning grating may not be provided; at this time, the projection of the optical path sheet 20 on the waveguide sheet 10 at least partially covers the coupling-out grating. By rationally planning the size of the optical path sheet 20, it is beneficial to ensure that the optical path sheet 20 can compensate for the optical path for the turning grating and the coupling-out grating or the region of the coupling-out grating, and ensure that the step length difference of different incident field angles is reduced, which is beneficial to reducing the uniformity difference of different fields of view and improving the display effect.

[0044] Specifically, the outcoupling portion is located on one side surface of the waveguide sheet 10, the optical path sheet 20 and the outcoupling portion are located on the same side or different sides of the waveguide sheet 10, and the projection of the optical path sheet 20 on the waveguide sheet 10 at least partially covers the projection of the outcoupling portion on the waveguide sheet 10. Preferably, the projection of the optical path sheet 20 on the waveguide sheet 10 completely covers the projection of the outcoupling portion on the waveguide sheet 10, and such a setting is conducive to ensuring that the step length difference of different incident field angles is reduced, which is conducive to reducing the uniformity difference of different fields of view and improving the display effect.

[0045] like Figure 1 As shown in FIG. 1 , the optical path diagram of the waveguide 10 is described at different angles. After the light emitted by the optical machine enters the waveguide 10 from the coupling port 11, it is reflected by the reflection surface 12 and propagates to the right in the waveguide 10 through total reflection. The distance between two total reflection points on the same surface of the waveguide 10 is the total reflection step length T. The total reflection step length of the light incident vertically on the coupling port 11 is T0. The incident angle of the total reflected light in the waveguide 10 to its surface is α. The total reflection step lengths of the light incident into the coupling port 11 with right and left tilt angles are respectively counted as T1 and T2; When the light rays incident on the coupling port 11 with right and left tilts are totally reflected, the incident angles of the light rays incident on the surface of the waveguide plate 10 are β and γ respectively. Figure 1 The thickness of the three waveguide plates 10 in FIG. 1 is d, and the unit is mm.

[0046] Among them, T0 = 2·d·tanα; T1 = 2·d·tanβ; T2 = 2·d·tanγ;

[0047] α=2θ; β=2θ-ω; γ=2θ+ω; θ is the angle between the reflection surface 12 and the surface of the waveguide plate 10 where the coupling port 11 is located.

[0048] from Figure 1It can be seen that the difference between T1 and T2 is the largest, and the difference ΔT = 2·d·(tanγ-tanβ).

[0049] The refractive index n of the waveguide plate 10 is wg =1.84, θ=25.7°, the thickness of the waveguide plate 10 d=1.5 mm,

[0050] Optical projection parameters: field of view D-FOV = 30°, screen ratio 16:9, It can be obtained that ΔT = 1.9687 mm. It can be seen that different angles of incidence on the waveguide plate 10 will introduce a large step length difference, resulting in large differences in uniformity in different fields of view. The step length directly determines the number of times the light contacts the light splitting layer within a certain propagation length range. When the number of light splitting layers decreases, the pupil separation phenomenon will become obvious. If it is guaranteed that there is no pupil separation in the field of view with a large total reflection cycle, the pupil overlap area in the field of view with a small total reflection cycle will inevitably increase, reducing its uniformity.

[0051] If the vertical line of the coupling port 11 is used as a reference, the clockwise angle is negative and the positive clockwise angle is positive, then α, β, and γ can be expressed as:

[0052]

[0053] The optical waveguide structure of the present application is described below in conjunction with specific embodiments and drawings.

[0054] Embodiment 1

[0055] like Figures 2 to 4 As shown, the optical waveguide structure of the first embodiment is described.

[0056] In the first embodiment, a coupling portion and an outcoupling portion are provided on the waveguide plate 10. The coupling portion is a coupling port 11 and a reflecting surface 12 that cooperate with each other. The angle between the reflecting surface 12 and the surface of the waveguide plate 10 where the coupling port 11 is located is θ. The optical path plate 20 is a single piece, and a single piece of the optical path plate 20 is provided on a side surface of the waveguide plate 10 where the coupling port 11 is not provided, and the projection of the optical path plate 20 on the surface where the optical path plate 20 is located is smaller than the surface area of ​​the surface.

[0057] like Figure 2 As shown, the total reflected light in the waveguide sheet 10 can enter the optical path sheet 20 for transmission and satisfy the following relationship:

[0058] T0=2·d·tanα;n wg ·sinα=n1·sinα1;

[0059] T0′=T0+2·d1·tanα1=2·(d·tanα+d1·tanα1);

[0060] Wherein, T0 and T0′ are both total reflection step lengths, d is the thickness of the waveguide plate 10, d1 is the thickness of the optical path plate 20, and n wg is the refractive index of the waveguide plate 10 , n1 is the refractive index of the optical path plate 20 , α is the angle at which the light in the waveguide plate 10 is incident on the side surface of the waveguide plate 10 where the optical path plate 20 is set, and α1 is the angle of the light incident on the optical path plate 20 .

[0061] like Figure 3 As shown, the total reflected light in the waveguide plate 10 does not enter the optical path plate 20 and is transmitted to satisfy the following relationship:

[0062] T0 = ​​2·d·tanα;

[0063] Therefore, for different viewing fields, the condition for the total reflected light in the waveguide plate 10 to enter the optical path plate 20 is That is, after adding 20 optical path slices, the functional relationship between the total reflection step length and FOV of different fields of view is converted into a piecewise function:

[0064]

[0065] According to this function, the relationship between the field of view angle and the step length can be obtained. Figure 4 As shown in , it can be seen from the figure that after adding the optical path plate 20, the total reflection step length of the small-angle incident light can be increased.

[0066] In this embodiment, the projection parameters of the light collecting machine are: field of view angle D-FOV = 30°, screen ratio 16:9, and can be matched with the following parameters: n wg =1.84, d=1.5mm, n1=1.5, d1=0.1mm, the FOV corresponding to the total reflection step length is shown in Figure 4. The total reflection step size has been improved, which is more conducive to reducing the uniformity differences in different fields of view.

[0067] Embodiment 2

[0068] like Figures 5 to 8 As shown, the optical waveguide structure of the second embodiment is described.

[0069] The difference between this embodiment and the first embodiment is that there are two optical path plates, namely a first optical path plate 21 and a second optical path plate 22, which are respectively arranged on the two side surfaces of the waveguide plate 10. The second optical path plate 22 is located on the side surface of the waveguide plate 10 having the coupling port 11, and the first optical path plate 21 is located on the side surface of the waveguide plate 10 not having the coupling port 11.

[0070] like Figure 5 As shown, the total reflected light in the waveguide plate 10 can enter the first optical path plate 21 and the second optical path plate 22 for transmission and satisfies the following relationship:

[0071] n wg ·sinα=n1·sinα1;n wg ·sinα=n1·sinα2;

[0072] T0′=T0+2·d1·tanα1+2·d2·tanα2=2·(d·tanα+d1·tanα1+d2·tanα2);

[0073] Wherein, T0 and T0′ are both total reflection step lengths, d is the thickness of the waveguide plate 10, d1 is the thickness of the first optical path plate 21, d2 is the thickness of the second optical path plate 22, and n wg is the refractive index of the waveguide plate 10, n1 is the refractive index of the first optical path plate 21, n2 is the refractive index of the second optical path plate 22, α is the angle at which the light in the waveguide plate 10 is incident to the side surface of the waveguide plate 10 where the optical path plate is located, α1 is the angle of the light incident to the first optical path plate 21, and α2 is the angle of the light incident to the second optical path plate 22.

[0074] like Figure 6 As shown, the total reflected light in the waveguide plate 10 only enters the second optical path plate 22, and does not enter the first optical path plate 21 for transmission, satisfying the following relationship:

[0075] n1 <n2<n wg ;

[0076] T0′=T0+2·d2·tanα2=2·(d·tanα+d2·tanα2).

[0077] like Figure 7 As shown, the total reflected light in the waveguide plate 10 only enters the first optical path plate 21, and does not enter the second optical path plate 22 for transmission, satisfying the following relationship:

[0078] n2 <n1<n wg ;

[0079] T0′=T0+2·d1·tanα1=2·(d·tanα+d1·tanα1).

[0080] Therefore, the condition for light to enter the first optical path sheet 21 is n1 <n wg and The condition for light to enter the second optical path plate 22 is n2 <n wg and The functional relationship between the total reflection step length and FOV is a piecewise function:

[0081] When n1>n2,

[0082]

[0083] When n1<n2,

[0084]

[0085] Projection parameters of the light collecting machine: field of view D-FOV = 30°, screen ratio 16:9, the optical waveguide structure meets the following parameter limitations: n wg =1.84, d=1.5mm, n1=1.45, d1=0.1mm, n2=1.51, d2=0.1mm, the FOV corresponding to the total reflection step length is shown in Figure 8. It can be seen from the figure The total reflection step length is increased, and compared with the first embodiment, the step length overlap within the range of -5° to 7° is further increased, which is more conducive to reducing the uniformity difference in different fields of view.

[0086] Obviously, the embodiments described above are only some embodiments of the utility model, not all embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the utility model.

[0087] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0088] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0089] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. An optical waveguide structure, characterized in that: include: A waveguide plate (10), wherein the waveguide plate (10) is provided with at least a coupling-in portion and a coupling-out portion; An optical path plate (20), wherein the optical path plate (20) is arranged on at least one side surface of the waveguide plate (10), the refractive index of the optical path plate (20) is smaller than the refractive index of the waveguide plate (10), and the difference between the refractive indexes of the waveguide plate (10) and the optical path plate (20) is less than or equal to 1, and the optical path plate (20) is used to receive light transmitted in the waveguide plate (10) and enable the light to be transmitted in the optical path plate (20).

2. The optical waveguide structure according to claim 1, characterized in that: The difference in refractive index between the waveguide plate (10) and the optical path plate (20) is greater than 0.2 and less than 0.

7.

3. The optical waveguide structure according to claim 1, characterized in that: The optical path sheet (20) is one sheet or multiple sheets. When the optical path sheet (20) is multiple sheets, A plurality of optical path plates (20) are arranged on only one side surface of the waveguide plate (10), and the plurality of optical path plates (20) are stacked and arranged in a direction away from the waveguide plate (10); or The optical path plates (20) are arranged on both side surfaces of the waveguide plate (10), and the number of the optical path plates (20) on the same side of the waveguide plate (10) is one or more.

4. The optical waveguide structure according to claim 1, characterized in that: The angle α at which the light in the waveguide plate (10) is incident on the surface of the waveguide plate (10), the refractive index n of the waveguide plate (10) wg The refractive index n of the optical path plate (20) satisfies:

5. The optical waveguide structure according to any one of claims 1 to 4, characterized in that: The thickness difference between two different positions of the optical path sheet (20) is less than or equal to 10 um; and / or The thickness of the optical path sheet (20) is greater than 0.05 mm and less than 2 mm.

6. The optical waveguide structure according to any one of claims 1 to 4, characterized in that: The thickness of the waveguide sheet (10) is greater than 0.2 mm and less than 2 mm; and / or The refractive index of the waveguide plate (10) is greater than 1.3 and less than 2.

2.

7. The optical waveguide structure according to any one of claims 1 to 4, characterized in that: The optical path sheet (20) is a glass sheet or a resin sheet.

8. The optical waveguide structure according to any one of claims 1 to 4, characterized in that: The optical path plate (20) and the waveguide plate (10) are integrally formed or the optical path plate (20) and the waveguide plate (10) are bonded together by a glue structure, and the absolute value of the refractive index difference between the glue structure and the optical path plate (20) is less than 0.01, or the absolute value of the refractive index difference between the glue structure and the waveguide plate (10) is less than 0.

01.

9. The optical waveguide structure according to any one of claims 1 to 4, characterized in that: The projection area of ​​the optical path plate (20) on the waveguide plate (10) is less than or equal to the surface area of ​​the waveguide plate (10) on which the optical path plate (20) is located; the outcoupling portion is located on a surface of one side of the waveguide plate (10); the optical path plate (20) and the outcoupling portion are located on the same side or different sides of the waveguide plate (10); and the projection of the optical path plate (20) on the waveguide plate (10) at least partially covers the projection of the outcoupling portion on the waveguide plate (10).

10. The optical waveguide structure according to any one of claims 1 to 4, characterized in that: The coupling-in portion is used to couple light projected by an external optical machine into the waveguide plate (10), and the coupling-in portion comprises a coupling-in port (11) and a reflecting surface (12) that cooperate with each other, a prism, and a diffraction element.

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