Optical waveguide unit, array and flat lens

Abstract

To provide an optical waveguide unit, an optical waveguide array, and a flat lens having the optical waveguide array.SOLUTION: An optical waveguide unit includes at least one total reflection layer set 1 and at least two sub-waveguides, each total reflection layer set includes at least one type of total reflection layer, each type of the total reflection layer includes at least one single total reflection layer, and one total reflection layer set is provided between each two adjacent sub-waveguides.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present disclosure relates to the field of optical displays, and in particular to a light guide unit, a light guide array including said light guide unit, and a flat lens including said light guide array. [Background technology]

[0002] With the development of aerial imaging display technology, the requirements for imaging characteristics continue to increase. On the one hand, higher resolution is required to ensure the clarity of the observed image while meeting the requirement of small distortion. On the other hand, the characteristics of three-dimensional stereoscopic display are required, as well as the requirements of naked-eye three-dimensional holographic display.

[0003] Existing imaging technologies mainly adopt lens imaging. Due to the limitations of the field of view and aperture, the lens imaging method has optical aberrations such as spherical aberration, coma aberration, astigmatism, field curvature, distortion, and chromatic aberration. Therefore, the lens imaging method is greatly limited in the field of large field of view and large aperture imaging display. In addition, most of the existing naked eye 3D display technologies are not real 3D display technologies, but realize 3D sensation based on the adjustment of parallax between the left and right eyes.

[0004] The principle diagram of the existence of a loss area when the incident light at a certain angle θ enters the equivalent light guide unit of the related art is shown in FIG. 1. b0' is the size of the loss area. At the same time, the equivalent light guide unit of the related art is relatively sensitive to the light incident at various angles. With the change of angle, the loss area of ​​the light guide for the light becomes larger, so that the loss of light energy becomes serious. At the same time, some of the lost light will cover the image surface to form ghost light, which affects the display effect. In addition, because the size of the loss area formed by the light incident at different angles is different, the light intensity of each viewing angle formed by concentrating the light passing through the flat lens of the related art is non-uniform, which affects the actual display effect. Summary of the Invention

[0005] The present disclosure aims to solve at least one of the technical problems in the prior art. Therefore, the present disclosure proposes an optical waveguide unit.

[0006] The present disclosure also discloses an optical waveguide array including the optical waveguide unit.

[0007] The present disclosure further discloses a flat lens including the optical waveguide array.

[0008] The optical waveguide unit according to an embodiment of the first aspect of the present disclosure includes at least one total reflection layer set and at least two sub-waveguides. Each total reflection layer set includes at least one type of total reflection layer. Each type of total reflection layer includes at least one single total reflection layer. One total reflection layer set is provided between each two adjacent sub-waveguides.

[0009] In the optical waveguide unit according to an embodiment of the present disclosure, a total reflection layer or a total reflection layer set is arranged between the sub-waveguides, and by making each type of total reflection layer correspond to different incident angles and optical refractive indexes, the light collection efficiency of the entire optical waveguide unit at a corresponding specific incident angle can be improved, and the uniformity of the light intensity over the entire viewing angle can be improved.

[0010] According to some embodiments of the present disclosure, in the stacking direction of the total reflection layer set and the sub-waveguides, the total height H of the optical waveguide unit satisfies 0.1 mm < H < 5 mm.

[0011] According to some embodiments of the present disclosure, the number of the sub-waveguides is two, and the total reflection layer set arranged between the two sub-waveguides includes one type of total reflection layer.

[0012] According to some embodiments of the present disclosure, the number of the sub-waveguides is four, and the number of the total reflection layer sets is three, including a first type of total reflection layer located in the center and two second type of total reflection layers. The refractive index of the second type of total reflection layer is different from that of the first type of total reflection layer. In the stacking direction of the total reflection layers and the sub-waveguides, the two second type of total reflection layers are located on both sides of the first type of total reflection layer, respectively.

[0013] According to some embodiments of the present disclosure, in the stacking direction, the heights of the four sub-waveguides are GH1, GH2, GH3, and GH4, respectively, where GH1=GH4=GH2+GH3, GH2=GH3, and GH1+GH2=GH3+GH4.

[0014] According to some embodiments of the present disclosure, the number of the sub-waveguides is 3, and the number of the fully reflective layer sets is 2. The refractive indices of the two fully reflective layer sets may be the same or different.

[0015] According to some embodiments of the present disclosure, the distribution of each type of the total reflective layers of the total reflective layer set can be expressed by the following formula: Fills JPEG0007659602000001.jpg15170, where comb(x) represents the comb function, In a stacking direction of the total reflection layer set and the sub-waveguide unit, one side surface of the optical waveguide unit serves as a reference surface; k is the total number of types of the total reflective layers, i is the number of the type of the total reflection layer and is an integer, x is the distance from a single total reflection layer of the i-th type of total reflection layer to the reference surface, num is the layer number of the i-th type of total reflective layer, Ti represents a positional period of the i-th type of total reflection layer, and the positional period is the shortest distance at which adjacent i-th type of total reflection layers appear in the optical waveguide unit; δ(x) is the impulse function.

[0016] According to some embodiments of the present disclosure, the position period T is calculated according to the following formula: JPEG0007659602000002.jpg10170 is calculated, where W is the width of a cross section of the optical waveguide unit, the direction of the width being perpendicular to the stacking direction in the cross section; θi is the angle of incidence corresponding to the i-th type of total reflection layer incident on the surface of the optical waveguide unit; n is the refractive index of the sub-waveguide.

[0017] According to some embodiments of the present disclosure, the thickness of each of the total reflective layers is 0.04 mm. <t<0.2Tiである。

[0018] According to some embodiments of the present disclosure, the range of refractive indexes of each type of the total reflective layer can be expressed by the following formula: JPEG0007659602000003.jpg12170 is calculated, where the parameter θi is a preset angle selected within the observation field of view angle range, and n is the optical refractive index of the sub-waveguide, n>1.4.

[0019] According to some embodiments of the present disclosure, in the stacking direction of the total reflection layer set and the sub-waveguide, a reflection layer is provided on both two side surfaces of the optical waveguide unit.

[0020] The optical waveguide unit according to the embodiment of the present disclosure can greatly reduce the loss of optical energy and improve the energy uniformity at each viewing angle.

[0021] An optical waveguide array according to an embodiment of the second aspect of the present disclosure includes a plurality of optical waveguide units according to the embodiment of the first aspect of the present disclosure, each of the optical waveguide units having a rectangular cross section, the optical waveguide units being joined in a line, an outer contour of the optical waveguide array having a rectangular shape, and an extension direction of the optical waveguide units forming an angle of 30 to 60 degrees with each of at least two sides of the outer contour of the optical waveguide array.

[0022] According to some embodiments of the present disclosure, the extension direction of the optical waveguide unit forms an angle of 45 degrees with each of at least two sides of the outer contour of the optical waveguide array.

[0023] According to some embodiments of the present disclosure, the plurality of the optical waveguide units are bonded to each other by an adhesive layer, and a thickness of the adhesive layer is greater than 0.001 mm.

[0024] A flat lens according to an embodiment of the third aspect of the present disclosure includes two transparent substrates and two optical waveguide arrays according to the embodiment of the second aspect of the present disclosure, each of the transparent substrates having two optical surfaces, the two optical waveguide arrays being disposed between the two transparent substrates by an adhesive, and the extension directions of the optical waveguides of the two optical waveguide arrays being disposed perpendicular to each other.

[0025] According to some embodiments of the present disclosure, an optical surface of each of the transparent substrates remote from the optical waveguide array is provided with a reflection enhancing coating.

[0026] The flat lens according to the embodiment of the present disclosure uses a single-column and multiple-row optical waveguide with a rectangular cross section to form an array structure, which can directly shape a two-dimensional or three-dimensional light source into a real image in air to realize a real holographic image, which has a good imaging effect and at the same time realizes the characteristics of a naked-eye three-dimensional stereoscopic display.

[0027] Additional aspects and advantages of the disclosure will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the disclosure. [Brief description of the drawings]

[0028] The above and / or additional aspects and advantages of the present disclosure will become apparent and easier to understand from the following description of the embodiments taken in conjunction with the drawings. [Figure 1] The principle of the equivalent optical waveguide unit of the prior art is that there is a lossy region when light is incident at a certain θ angle. [Figure 2a]FIG. 2 is a schematic diagram of an optical waveguide array according to an embodiment of the present disclosure, in which two optical waveguide arrays are arranged orthogonally. [Figure 2b] FIG. 2B is an enlarged view of the box G in FIG. 2a. [Figure 3a] FIG. 2b is a schematic diagram of the two sub-waveguides shown in FIG. 2b joined by an adhesive layer. [Figure 3b] FIG. 3b is a cross-sectional view of any sub-waveguide of FIG. 3a, where W is the width and H is the height. [Figure 4] FIG. 13 is a diagram illustrating the principle of modulated light in an overlapping region when two optical waveguide units according to an embodiment of the present disclosure are disposed perpendicular to each other. [Diagram 5] FIG. 1 is a diagram illustrating the principle of imaging when two optical waveguide arrays according to an embodiment of the present disclosure are perpendicular to each other. [Figure 6] 1 is a diagram illustrating the principle of an optical waveguide unit according to an embodiment of the present disclosure, in which a loss region exists when light is incident at an angle θ. [Figure 7] FIG. 13 is a diagram illustrating the principle of reflection and transmission of light greater than the critical angle of the total reflection layer and light smaller than the critical angle of the total reflection layer after a total reflection layer and a sub-waveguide are arranged in an optical waveguide unit according to an embodiment of the present disclosure. [Figure 8] FIG. 2 is a comparison diagram of the energy uniformity and stray light at each viewing angle of a light guide unit according to an embodiment of the present disclosure and an equivalent light guide unit shown in FIG. [Figure 9] 1 is a schematic diagram of an internal structure of an optical waveguide unit according to an embodiment of the present disclosure. [Figure 10] 10 is a cross-sectional view of the optical waveguide unit shown in FIG. 9. [Figure 11] FIG. 2 is a schematic diagram of a flat lens according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the embodiments of the present disclosure will be described in detail. The embodiments will be described with reference to the accompanying drawings, which are merely illustrative. Hereinafter, the embodiments of the present disclosure will be described in detail.

[0030] Hereinafter, an optical waveguide array according to an embodiment of the present disclosure will be described with reference to FIGS.

[0031] As shown in FIG. 1, the optical waveguide arrays 1000a, 1000b include a plurality of optical waveguide units 100, each of which has a rectangular cross section, and the plurality of optical waveguide units 100 are joined side by side. The outer contour of the optical waveguide array has a rectangular shape, and the extending direction of the optical waveguide unit 100 forms an angle of 30 to 60 degrees with each of at least two sides of the outer contour of the optical waveguide array. Optionally, the extending direction of the optical waveguide unit 100 forms an angle of 45 degrees with each of at least two sides of the outer contour of the optical waveguide array. Of course, the present disclosure is not limited thereto, and a large size requirement can be realized by splicing a plurality of optical waveguide arrays when displaying on a large screen. The overall shape of the optical waveguide array is set according to the scene of use.

[0032] In the example shown in FIG. 1, the outer contours of the light guide arrays 1000a, 1000b are both rectangular. As shown in FIG. 2a, the length of the light guide units extending between the two diagonals of the rectangle is the longest. The light guide units 100 at the two diagonals are triangular and have the shortest length. The central light guide unit is a trapezoid or parallelogram structure, and the lengths of the individual light guides are not equal. In some further optional examples, the light guide units extending between the two diagonals of the rectangle are used as a reference, and the light guide units located on both sides of it can be arranged symmetrically.

[0033] The extension directions of the optical waveguides of the two optical waveguide arrays 1000a and 1000b are arranged perpendicular to each other so as to form flat lenses with the same negative refractive index. The extension direction of each optical waveguide of the optical waveguide array 1000a is also perpendicular to the extension direction of each optical waveguide of the optical waveguide array 1000b.

[0034] Figure 4 shows the principle diagram of modulated light in the overlapping area when two optical waveguide units are arranged orthogonally. a, b represent two optical waveguide units, A, B represent odd-order reflected light beams, C represents transillumination stray light, D is the imaging light beam, O represents the light source point on the object side, and Ox represents the imaging point on the image side. As shown in Figure 5, when two optical waveguide units are arranged orthogonally, the light beams on the object plane and the image plane are mirror symmetric with respect to the flat lens with the same negative refractive index, and the phenomenon of negative refractive index occurs, and imaging by the flat lens is realized.

[0035] In some embodiments of the present disclosure, as shown in Fig. 3a, multiple optical waveguide units 100 are bonded together by an adhesive layer 4, and the thickness of the adhesive layer 4 is greater than 0.001 mm. The adhesive layer 4 is, for example, a photosensitive adhesive or a heat-sensitive adhesive.

[0036] Hereinafter, an optical waveguide unit according to an embodiment of the present disclosure will be described with reference to FIGS.

[0037] The optical waveguide unit 100 according to an embodiment of the present disclosure includes at least one total reflection layer set 1 and at least two sub-waveguides 2, and one total reflection layer set 1 is provided between each two adjacent sub-waveguides 2. Each total reflection layer set 1 includes at least one type of total reflection layer 11, and each type of total reflection layer corresponds to one incident angle and has a different optical refractive index. Each type of total reflection layer 11 includes at least one single total reflection layer, and the optical refractive index of each type of single total reflection layer is the same.

[0038] In the optical waveguide unit 100 according to the embodiment of the present disclosure, a total reflection layer 11 or a total reflection layer set 1 is disposed between the sub-waveguides 2, and each type of total reflection layer corresponds to a different incident angle and optical refractive index, thereby improving the light collection efficiency of the entire optical waveguide unit 11 at a corresponding specific incident angle and improving the uniformity of the light intensity across the entire viewing angle.

[0039] Optionally, the material of the total reflection layer used in the light guide unit 100 according to the embodiment of the present disclosure includes optical adhesive, optical plastic, optical glass, and so on.

[0040] The specific principle of the optical waveguide unit 100 according to the embodiment of the present disclosure will be described below.

[0041] Please refer to Figure 4. The incident light from the light source point O on the object side is reflected inside the equivalent light guide unit, and then split into four beams as shown in the figure, one beam participates in imaging, and three beams form interference stray light, which are A, B and C, respectively. In order to reduce the influence of ghost image formed by stray light on imaging, the directions of the two sets of light guide arrays are arranged orthogonal to each other along 45°.

[0042] As mentioned above, each optical waveguide unit is prone to generate stray light, which is a part of the original object light but does not participate in imaging, and therefore becomes lost light. As shown in Figure 1, when a light beam is incident on the optical waveguide array of the related art at a certain incident angle, there is a loss area of ​​size b0'. Because the light source on the object side is a light source with a large divergence angle, this incident angle changes continuously with the emission of different light from the light source. The smaller the angle, the larger the loss area, and the more serious the light loss, which greatly reduces the utilization rate of the light energy of the flat lens composed of the optical waveguide array. In addition, different incident angles will result in different energy losses, which will cause the energy non-uniformity of each visual angle, affecting the effect of the observer observing the object at different visual angles.

[0043] In order to make full use of light energy and improve the energy uniformity at each incident angle, as shown in FIG. 6, a plurality of sub-waveguides 2 and a total reflection layer set 1 or a total reflection layer 11 between the sub-waveguides 2 are arranged in the optical waveguide unit according to an embodiment of the present disclosure, so that the light energy in the loss region b0 can be differentiated and collected by the total reflection layer and the sub-waveguides, thereby reducing the loss region b0 of the incident light incident at the angle θ. As shown in FIG. 7, the function of the total reflection layer 11 is as follows. By totally reflecting the light incident on the surface of the optical waveguide unit at an angle larger than the critical angle and transmitting the light incident on the surface of the optical waveguide unit at an angle smaller than the critical angle, the purpose of accurately modulating the light near the critical angle can be realized. Therefore, in the present application, in order to realize accurate modulation of the light near a plurality of critical angles, it is necessary to arrange a plurality of types of total reflection layers 11 in a single optical waveguide unit 100 and divide the single optical waveguide unit 100 into a plurality of sub-waveguides 1.

[0044] As shown in FIG. 8, the one on the left is a normal optical waveguide unit in the related art, and the one on the right is an optical waveguide unit according to an embodiment of the present disclosure. The figure shows a comparison of the energy uniformity and stray light at various viewing angles for both. It can be seen that the optical waveguide unit 100 according to the embodiment of the present disclosure can greatly reduce the loss of light energy and improve the energy uniformity at each viewing angle.

[0045] As shown in FIGS. 3b and 9, in the stacking direction of the total reflection layer set 1 and the sub-waveguide 2, the total height H of the optical waveguide unit 100 satisfies 0.1 mm < H < 5 mm. Also, the width of the cross-section of the optical waveguide unit 100 is W, and the direction of the width w in the cross-section is perpendicular to the stacking direction, that is, the direction of the above height H. W also satisfies 0.1 mm < W < 5 mm.

[0046] According to some embodiments of the present disclosure, in the simple example of Fig. 7, the number of sub-waveguides 2 is two, which are sub-waveguides 21 and 22, respectively. The total reflection layer set 1 disposed between the two sub-waveguides 2 includes one type of total reflection layer 11. As a result, light near one critical angle can be precisely modulated.

[0047] In some other embodiments of the present disclosure, as shown in FIG. 9, there are four sub-waveguides 221, 222, 223, 224, and the number of the total reflection layer set 1 is three, including a first type of total reflection layer 1121 located in the center and two second type of total reflection layers 1122. The refractive index of the second type of total reflection layer 1122 is different from that of the first type of total reflection layer 1121. In the stacking direction of the total reflection layer 11 and the sub-waveguide 2, the two second type of total reflection layers 1122 are located on both sides of the first type of total reflection layer 11, respectively. In the optional example shown in FIG. 10, in the stacking direction, the heights of the four sub-waveguides 2 are GH1, GH2, GH3, GH4 in order, where GH1=GH4=GH2+GH3, GH2=GH3, GH1+GH2=GH3+GH4. In this way, most of the light on the object side corresponding to the selected incident angle can be collected, and the energy utilization rate of the imaging light beam and the uniformity of the light beam can be improved.

[0048] In some other embodiments of the present disclosure, the number of sub-waveguides 2 is three, the number of fully reflective layer sets 1 is two, and the refractive indices of the two fully reflective layer sets 1 are the same or different (not shown).

[0049] Of course, the present disclosure is not limited to the above embodiments. According to some embodiments of the present disclosure, the distribution of each type of total reflective layer 11 in the total reflective layer set 1 satisfies the following formula: JPEG0007659602000004.jpg15170Here, comb(x) represents the comb function, In the stacking direction of the total reflection layer set 1 and the sub-waveguide 2 unit, one side surface of the optical waveguide unit 100 serves as a reference surface, k is the total number of types of total reflective layers 11, i is the number of the type of the total reflection layer 11 and is an integer, x is the distance from a single total reflective layer 11 of the i-th type to the reference plane, num is the layer number of the single total reflective layer 11 of the i-th type of total reflective layer 11, Ti represents the position period of the i-th type total reflection layer 11, and the position period is the shortest distance at which adjacent i-th type total reflection layers 11 appear in the optical waveguide unit 100, δ(x) is the impulse function.

[0050] In a further embodiment, the position period Ti can also be calculated by the following formula: JPEG0007659602000005.jpg11170Here, W is the cross-sectional width of the optical waveguide unit 100, the width direction in the cross section is perpendicular to the stacking direction, θi is the incident angle corresponding to the i-th type of total reflection layer 11 incident on the surface of the optical waveguide unit 100, and n is the refractive index of the sub-waveguide 2.

[0051] For example, in the example shown in FIG. 9 and FIG. 10, there are four sub-waveguides 221, 222, 223, 224, and two kinds of total reflection layers 11. The total reflection layers 11 include a first type total reflection layer 1121 located in the center, and two second type total reflection layers 1122. Here, GH1=GH4=T2=GH2+GH3, GH2=GH3, GH1+GH2=T1=GH3+GH4. T1 is the period of the first type total reflection layer calculated by the above formula when the selected incident angle is θ1. T2 is the period of the second type total reflection layer calculated by the above formula when the selected incident angle is θ2. As shown in FIG. 10, T1 is the shortest distance where the first type total reflection layer 11 appears, and T2 is the shortest distance where the second type total reflection layer 11 appears.

[0052] Of course, the present disclosure is not limited thereto. In some other embodiments, when the number of sets, types, and layers of the total reflection layer 11 are different, the position period of the corresponding type of total reflection layer is calculated using the above formula 2, and then the distribution status of each total reflection layer 11 of each type is calculated according to formula 1, so as to more accurately design the internal structure of the entire optical waveguide unit 100. More preferably, the cross-sectional height H of the optical waveguide unit is an integer multiple of the position period Ti.

[0053] In some option examples, the thickness of each layer of each type of total reflective layer is 0.04mm. <t<0.2Tiである。

[0054] In some embodiments of the present disclosure, the refractive index range nei of each type of total reflective layer 11 is calculated as follows: JPEG0007659602000006.jpg14170, where the parameter θi is a preset angle selected within the observation viewing angle range, and n is the optical refractive index of the sub-waveguide 2, where n>1.4. In the optical waveguide unit according to the embodiment of the present disclosure, each type of total reflection layer has one θi, n ei This θi angle is an angle selected within the observed viewing angle range to improve the light collection efficiency at the corresponding angle and improve the light intensity uniformity across the viewing angle.

[0055] It should be noted that, in order to improve the collection effect in the loss region, the parties involved can appropriately increase or decrease the number of the total reflection layers and the number of the sub-waveguides of the optical waveguide unit 10 during execution to meet the light collection requirements. If the light in the loss region needs to be collected simultaneously for multiple incident angles, multiple types of total reflection layers are required. The embodiments of the present disclosure do not impose any restrictions on the number of types of total reflection layers and the number of layers.

[0056] In a further embodiment of the present disclosure, as shown in Figures 9 and 10, a reflective layer 3 is disposed on both sides of the optical waveguide unit 100 in the stacking direction of the total reflection layer set 1 and the sub-waveguide 2. Optionally, the reflective layer 3 here adopts an aluminum film, which can further reduce the light loss to a certain extent.

[0057] Hereinafter, a flat lens according to an embodiment of the third aspect of the present disclosure will be described with reference to Fig. 11. The flat lens includes two transparent substrates 2000 and two optical waveguide arrays 1000a and 1000b according to the above embodiments.

[0058] Each transparent substrate 2000 has two optical surfaces. The optical surfaces are used to protect the optical waveguide arrays 1000a, 1000b. The two optical waveguide arrays are arranged between the two transparent substrates 2000 by adhesive, and the extension directions of the optical waveguides of the two optical waveguide arrays are arranged orthogonally, that is, the extension directions of the optical waveguide units are perpendicular to each other. Thereby, the light beam is focused to a point, and the object plane and the image plane are guaranteed to be symmetrical with respect to the flat lens with the same negative refractive index, and the phenomenon of negative refractive index is generated, and the imaging by the flat lens is realized.

[0059] Optionally, the optical waveguide array and the transparent substrate 2000 are attached to each other by a photosensitive or heat sensitive adhesive.

[0060] In some embodiments of the present disclosure, as shown in FIG. 11, an anti-reflection film 210 is disposed on the optical surface of each transparent substrate 200 remote from the optical waveguide array to further improve the imaging effect.

[0061] The flat lens according to the embodiment of the present disclosure uses a single-column and multiple-row optical waveguide with a rectangular cross section to form an array structure, which can directly shape a two-dimensional or three-dimensional light source into a real image in air to realize a real holographic image, which has a good imaging effect and at the same time realizes the characteristics of a naked-eye three-dimensional stereoscopic display.

[0062] In the description of the present disclosure, the orientations or positional relationships indicated by terms such as "length," "width," "thickness," "up," "down," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," "outside," and the like, based on the orientations or positional relationships shown in the drawings, are merely for the purpose of facilitating and simplifying the description of the present disclosure, and are not intended to indicate or suggest that the devices or components referenced necessarily have a particular orientation, are constructed and operated in a particular orientation, and are therefore not intended to be limiting of the present disclosure.

[0063] In the description herein, a description that refers to terms such as "one embodiment," "some embodiments," "exemplary embodiments," "examples," "particular examples," or "some examples" means that the particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the disclosure. As used herein, exemplary appearances of the above terms do not necessarily refer to the same embodiment or example.

[0064] Although embodiments of the present disclosure have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present disclosure. The scope of the present disclosure is limited by the claims and their equivalents. [Explanation of symbols]

[0065] Optical waveguide arrays 1000a, 1000b Optical waveguide unit 100; total reflection layer set 1; total reflection layer 11; Sub-waveguide 2; reflective layer 3; adhesive layer 4; First embodiment: sub-waveguides 211, 212; total reflection layer 111; Example 2: Sub-waveguides 221, 222, 223, 224; first type total reflection layer 1121; second type total reflection layer 1122 Transparent substrate 2000; anti-reflection film 2100.

Claims

1. A waveguide including three total reflection layer sets and four sub-waveguides, Each of the total reflective layer sets includes a plurality of types of total reflective layers, and each type of the total reflective layers includes at least one single total reflective layer; One of the total reflection layer pairs is disposed between each two adjacent sub-waveguides; The three total reflective layer sets are a first total reflective layer set, a second total reflective layer set, and a third total reflective layer set, respectively, the first total reflective layer set includes one first type total reflective layer, the second total reflective layer set includes one second type total reflective layer, and the third total reflective layer set includes one second type total reflective layer; an optical waveguide unit, characterized in that a refractive index of the second type of total reflection layer is different from a refractive index of the first type of total reflection layer, and in a stacking direction of the total reflection layers and the sub-waveguide, the two second type of total reflection layers are located on both sides of the first type of total reflection layer.

2. 2. The optical waveguide unit according to claim 1, wherein a total height H of the optical waveguide unit in a stacking direction of the total reflection layer set and the sub-waveguide satisfies 0.1 mm<H<5 mm.

3. 2. The optical waveguide unit according to claim 1, wherein in the stacking direction, the heights of the four sub-waveguides are GH1, GH2, GH3, and GH4, respectively, where GH1=GH4=GH2+GH3, GH2=GH3, and GH1+GH2=GH3+GH4.

4. The distribution of each type of total reflective layer in the total reflective layer group is expressed by the following formula: Fulfilling where comb(x) represents the comb function, In a stacking direction of the total reflection layer set and the sub-waveguide, one side surface of the optical waveguide unit serves as a reference surface; k is the total number of types of the total reflective layers, i is the number of the type of the total reflection layer and is an integer, x is the distance from a single total reflection layer of the i-th type of total reflection layer to the reference surface, num is the layer number of the single total reflective layer of the i-th type of total reflective layer, Ti represents a position period of the i-th type of total reflection layer, and the position period is the shortest distance at which adjacent i-th type total reflection layers appear in the optical waveguide unit; m ｉ is the total number of all reflective layers of the i-th type, 4. The optical waveguide unit according to claim 1, wherein δ(x) is an impulse function.

5. The position period Ti is expressed by the following formula: This can be calculated as where W is the width of a cross section of the optical waveguide unit, the direction of the width being perpendicular to the stacking direction in the cross section; θi is the angle of incidence corresponding to the i-th type of total reflection layer incident on the surface of the optical waveguide unit; 5. The optical waveguide unit according to claim 4, wherein n is a refractive index of the sub-waveguide.

6. 6. The optical waveguide unit according to claim 4, wherein the thickness of each of the total reflection layers is in the range of 0.04 mm<t<0.2 Ti.

7. The refractive index nei of each type of the total reflection layer is expressed by the following formula: It is calculated as Here, the parameter θi is a preset angle selected within the observation viewing angle range, n is the optical refractive index of the sub-waveguide, and n>1.

4. The optical waveguide unit according to any one of claims 1 to 6.

8. The optical waveguide unit according to any one of claims 1 to 7, characterized in that a reflective layer is disposed on both of the two side surfaces of the optical waveguide unit in the stacking direction of the total reflection layer set and the sub-waveguide.

9. An optical waveguide array comprising a plurality of optical waveguide units according to any one of claims 1 to 8, each of the optical waveguide units having a rectangular cross section, the plurality of optical waveguide units being joined together in a line; An optical waveguide array, characterized in that an outer contour of the optical waveguide array is rectangular, and the extension direction of the optical waveguide unit forms an angle of 30 to 60 degrees with each of at least two sides of the outer contour of the optical waveguide array.

10. 10. The optical waveguide array according to claim 9, wherein the extending direction of the optical waveguide unit forms an angle of 45 degrees with each of at least two sides of an outer contour of the optical waveguide array.

11. 11. The optical waveguide array according to claim 9, wherein the plurality of optical waveguide units are bonded to one another by an adhesive layer, the adhesive layer having a thickness greater than 0.001 mm.

12. A flat lens comprising two transparent substrates and two optical waveguide arrays according to any one of claims 9 to 11; Each of the transparent substrates has two optical surfaces; A flat lens, characterized in that the two optical waveguide arrays are disposed between the two transparent substrates by an adhesive, and the extension directions of the optical waveguides of the two optical waveguide arrays are disposed perpendicular to each other.

13. 13. The flat lens according to claim 12, wherein an optical surface of each of the transparent substrates remote from the optical waveguide array is provided with a reflection enhancing film.

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