CN210005808U

CN210005808U - Optical waveguide unit, array and flat lens

Info

Publication number: CN210005808U
Application number: CN201920989395.0U
Authority: CN
Inventors: 范超; 韩东成
Original assignee: Anhui Province East Ultra Technology Co Ltd
Current assignee: Anhui Province East Ultra Technology Co Ltd
Priority date: 2019-06-26
Filing date: 2019-06-26
Publication date: 2020-01-31
Anticipated expiration: 2029-06-26

Abstract

The utility model discloses an kinds of optical waveguide unit, including a plurality of reflection units, the constitution of reflection unit is all the same, reflection unit is the combination of arbitrary kind or arbitrary two kinds in metal level, total reflection layer, the medium reflection layer, and a plurality of sub-waveguides that range upon range of setting each other, every the both sides of sub-waveguide have respectively reflection unit, and in a plurality of sub-waveguide's range upon range of direction, at least two in a plurality of sub-waveguide's height are different, the different angle of incidence direction that corresponds of sub-waveguide's different height value, according to the utility model discloses an optical waveguide unit, through setting up a plurality of high sub-waveguides, modulates to different visual angles under a plurality of heights respectively to can realize distributing the energy of a plurality of lossless district angles, thereby can improve the homogeneity of imaging beam energy in whole imaging visual angle scope.

Description

Optical waveguide unit, array and flat lens

Technical Field

The utility model belongs to the technical field of the optical display and specifically relates to kinds of optical waveguide units, include the optical waveguide array of optical waveguide unit and include the slab lens of optical waveguide array.

Background

The requirements for imaging characteristics are continuously improved along with the development of imaging display technology, the requirements for higher resolution in aspect are required, the requirements for small distortion are also required while the definition of an observed picture is ensured, in addition, the requirements for three-dimensional stereoscopic display characteristics and naked eye three-dimensional holographic display requirements are required in aspect, in the aspect of the existing imaging technology , lens imaging is mainly adopted and is mainly limited by a field of view and an aperture, optical aberrations such as spherical aberration, coma aberration, astigmatism, field curvature, distortion and chromatic aberration exist, the limitation is larger in the field of large-field-of-view and large-aperture imaging display, in addition, in aspect, the existing naked eye three-dimensional display technology is mostly based on adjusting left-eye parallax and right-eye parallax to realize three-dimensional sense, and is not an actual three-dimensional display.

SUMMERY OF THE UTILITY MODEL

The utility model discloses aim at solving of the technical problem that exists among the prior art at least for this reason, the utility model provides a kinds of optical waveguide unit.

The kinds of optical waveguide units according to the embodiment of the utility model comprise a plurality of reflecting units, wherein the reflecting units are all the same in structure, the reflecting units are arbitrary kinds or arbitrary two kinds of combinations in a metal layer, a total reflection layer and a medium reflecting layer, a plurality of sub-waveguides are stacked on one another, reflecting units are arranged on two sides of each sub-waveguide respectively, at least two of the heights of the sub-waveguides are different in the stacking direction of the sub-waveguides, and the different height values of the sub-waveguides correspond to different incident angle directions.

According to the utility model discloses optical waveguide unit, through setting up the sub-waveguide of a plurality of heights, modulate to different visual angles under a plurality of heights respectively to can realize distributing the energy of a plurality of lossless district angles, thereby can improve the homogeneity of imaging beam at whole formation of image visual angle within range energy.

According to the utility model discloses an some embodiments, every sub-waveguide's height scope is 0.1mm-5 mm.

According to of the present invention, the sub-waveguide has a refractive index n > 1.46.

According to some embodiments of the present invention at , the plurality of sub-waveguides includes a plurality of types, and the height of each type of sub-waveguide is the same, wherein the height of the i-th type of sub-waveguide satisfies:

wherein the parameter theta_iA predetermined angle selected for a range of viewing angles, n being the optical refractive index of the sub-waveguide;

wherein the height of the plurality of types of sub-waveguides is inversely proportional to the number of corresponding sub-waveguides.

According to some embodiments of the present invention at , the reflection unit is kinds of metal layer, metal layer and total reflection layer, metal layer and medium reflection layer.

According to , the metal layer is made of Ag, Al or Cr, and the height hm of the metal layer is 0.001mm < hm <0.1mm

According to the embodiments of the present invention, when the reflection unit is a metal layer and a total reflection layer, or a metal layer and a dielectric reflection layer, a side surface of the metal layer facing the corresponding sub-waveguide has a predetermined roughness, and/or the metal layer is a metal film layer that is oxidized and blackened.

According to the utility model discloses an some embodiments, the reflection element is the total reflection layer, the refracting index scope n on total reflection layer_eiCalculated by the following formula:

wherein, the parameter θ ei is the maximum incident angle of the surface of the optical waveguide unit when the total reflection condition is satisfied, and n is the optical refractive index of the sub-waveguide.

According to embodiments of the present invention, the height H2 of the total reflection layer satisfies 0.004mm < hr < (0.1H), where H is the height of the corresponding sub-waveguide where the total reflection layer is located.

According to , the reflective unit is an interference dielectric reflective layer comprising or more transparent dielectric layers 1/4 and 1/2 wavelength films, wherein the optical thickness of the 1/4 wavelength film is 1/4 of the wavelength of the incident light, and the optical thickness of the 1/2 wavelength film is 1/2 of the wavelength of the incident light, wherein the optical thickness T is n_gL, wherein n_gIs the refractive index of the film material, and l is the film thickness.

According to the embodiments of the present invention, the height hj of the dielectric reflective layer satisfies hj < (0.1H), where H is the height of the corresponding sub-waveguide where the total reflection layer is located.

kinds of optical waveguide arrays according to the embodiment of the second aspect of the present invention, including a plurality of optical waveguide units according to the embodiment of the present invention of the aspect, each of the cross sections of the optical waveguide units is rectangular and a plurality of the optical waveguide units are joined in parallel, the outer contour of the optical waveguide array is rectangular, and the extending direction of the optical waveguide units and at least two sides of the outer contour of the optical waveguide array are all in an angle of 30-60 degrees.

According to , the extending direction of the optical waveguide unit and at least two sides of the outer contour of the optical waveguide array form an angle of 45 degrees.

According to the utility model discloses an some embodiments, it is a plurality of joint through the viscose layer between the optical waveguide unit, the thickness on viscose layer is greater than 0.001 mm.

The kinds of flat lenses according to the third aspect of the present invention include two transparent substrates, each of which has two optical surfaces, and two optical waveguide arrays according to the second aspect of the present invention, wherein the two optical waveguide arrays are disposed between the two transparent substrates through adhesive, and the optical waveguide extending directions of the two optical waveguide arrays are orthogonally arranged.

According to , each transparent substrate is provided with an antireflection film on its optical surface away from the optical waveguide array.

Additional aspects and advantages of the invention 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 invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1a is a schematic diagram of an optical waveguide array according to an embodiment of the present invention, wherein two optical waveguide arrays are arranged orthogonally;

FIG. 1b is an enlarged view of FIG. 1a at block G;

FIG. 2a is a schematic view of the two sub-waveguides shown in FIG. 2b mated by an adhesive layer;

FIG. 2b is a cross-sectional view of any sub-waveguides of FIG. 2a, where W is the width and H is the height;

fig. 3 is a schematic diagram of modulated light in an overlapping region when two optical waveguide units are orthogonally disposed according to an embodiment of the present invention;

fig. 4 is an imaging schematic diagram of two optical waveguide arrays in quadrature according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of an equivalent optical waveguide unit of the prior art when the incident light at an angle of θ a has no loss region;

FIG. 6 is a schematic diagram of an equivalent optical waveguide unit of the prior art when the incident light at an angle of θ b has no loss region;

fig. 7 is a schematic diagram of light incidence of the optical waveguide unit according to an embodiment of the present invention;

fig. 8 is a schematic diagram of optical waveguide units according to embodiments of the present invention;

fig. 9 is a schematic diagram of an optical waveguide unit in accordance with another embodiments of the present invention;

fig. 10 is a schematic diagram of an optical waveguide unit according to embodiments of the present invention, wherein the reflective element is a metal layer;

fig. 11 is a schematic diagram of another embodiments of the optical waveguide unit according to the present invention, wherein the reflecting unit is a total reflecting layer or an interference type dielectric reflecting layer;

fig. 12 is a schematic diagram of an optical waveguide unit according to embodiments of the present invention, wherein the reflecting unit is a combination of a metal layer and a total reflection layer or an interference type dielectric reflecting layer;

fig. 13 is a schematic diagram of a planar lens according to an embodiment of the present invention.

Reference numerals:

optical waveguide arrays

1000a, 1000 b;

an optical waveguide unit 100; a reflection unit 1; a sub-waveguide 2;

a transparent substrate 2000; an anti-reflection film 2100.

Detailed Description

Embodiments of the present invention are described in detail below, and the embodiments described with reference to the drawings are exemplary.

In the description of the present invention, it is to be understood that the terms "height," "thickness," "top," "bottom," and the like are used in the orientation or positional relationship shown in the drawings for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be considered limiting of the present invention.

An optical waveguide array according to an embodiment of the present invention is described below with reference first to fig. 1 to 5.

As shown in fig. 1a and 1b, the

optical waveguide array

1000a, 1000b includes a plurality of optical waveguide units 100, each optical waveguide unit 100 having a rectangular cross section and the plurality of optical waveguide units 100 being joined in parallel. The outline of the optical waveguide array is rectangular, and the extending direction of the optical waveguide unit 100 and at least two sides of the outline of the optical waveguide array form an angle of 30-60 degrees. Optionally, the extending direction of the optical waveguide unit 100 is at an angle of 45 degrees with at least two sides of the outer contour of the optical waveguide array. Of course, the utility model discloses be not limited to this, can realize the jumbo size demand through splicing polylith optical waveguide array when the large screen display. The overall shape of the optical waveguide array is set according to the application scene.

In the example shown in fig. 1a, the outer contours of the

optical waveguide arrays

1000a, 1000b are both rectangular, as shown in fig. 1b, the optical waveguide units extending between two opposite corners of the rectangle have the longest length, the optical waveguide units 100 located at the two opposite corners have the triangular shape and the shortest length, the middle optical waveguide unit has a trapezoidal or parallelogram structure, and the lengths of the individual optical waveguides are not equal, in an alternative example of or , the optical waveguide units extending between the two opposite corners of the rectangle are used as references, and the optical waveguide units located at both sides thereof may be symmetrically arranged.

The directions of extension of the optical waveguides of the two

optical waveguide arrays

1000a, 1000b are orthogonally arranged to form equivalent negative index planar lenses, wherein the direction of extension of each optical waveguide in the optical waveguide array 1000a is also orthogonal to the direction of extension of each optical waveguide in the optical waveguide array 1000 b.

Fig. 3 is a schematic diagram of modulated light in an overlapping region when two optical waveguide units are orthogonally disposed, where a and b denote the two optical waveguide units, A, B denotes an odd-order reflected light beam, C denotes a transmitted stray light, D denotes an imaging light beam, O denotes an object-side light source point, and Ox denotes an image-side imaging point, so that when the two optical waveguide units are orthogonally disposed, the object-side light beam is mirror-symmetric with respect to an equivalent negative-refractive-index flat lens, and a negative-refractive-index phenomenon occurs, thereby realizing flat-lens imaging, as shown in fig. 5.

In the embodiments of the present invention, as shown in fig. 2a, the plurality of optical waveguide units 100 are connected by the adhesive layer 4, the thickness of the adhesive layer 4 is greater than 0.001 mm.

An optical waveguide unit according to an embodiment of the present invention is described below with reference to fig. 5 to 12.

The kinds of optical waveguide units 100 according to embodiments of the present invention include a plurality of reflection units 1 and a plurality of sub-waveguides 2 stacked on each other, each sub-waveguide 2 has reflection units 1 on both sides thereof, respectively, the reflection units 1 are any or any two combinations of a metal layer 1a, a total reflection layer 1b and a dielectric reflection layer 1c, that is, the reflection units 1 may have several ways, namely, a metal layer 1a, a total reflection layer 1b, a dielectric reflection layer 1c, a combination of the metal layer 1a and the dielectric reflection layer 1b, a combination of the metal layer 1a and the dielectric reflection layer 1c, a combination of the total reflection layer 1b and the dielectric reflection layer 1c, wherein the reflection units 1 in the same optical waveguide units are all the same in structure, that is, all the metal layer 1a, or all the combination of the metal layer a and the total reflection layer 1b, and the like.

And at least two of the heights of the plurality of sub waveguides 2 are different in the stacking direction of the plurality of sub waveguides 2, and the different height values of the sub waveguides 2 correspond to different incident angle directions.

The following description is made on the specific principle of the optical waveguide unit 100 according to the embodiment of the present invention.

As shown in FIG. 5 and FIG. 6, when optical waveguide units only comprise optical waveguides, the optical waveguide units have a loss-free region angle and a loss region angle after light is incident, with the angle change of incident light, as shown in FIG. 6, for the loss region angle, the light of the partial loss region does not participate in imaging, but is used as stray light loss imaging beam energy, and the energy corresponding to the angle is the largest when the light energy is distributed in the loss region, and the light energy larger than or smaller than the angle is reduced, so that the uniformity of the imaging beam angle is reduced.

In the example shown in FIG. 8, sub-waveguides are used in the optical waveguide unit, and there are two types of sub-waveguides in the different types of sub-waveguides, where there are corresponding loss-free regions θ a and θ b, the size of the cross-section of the energy collected by the different sub-waveguides for the light beams at different angles of loss-free region is related to the height Hi of the sub-waveguide cross-section, the sub-waveguide with large height Hi of cross-section has large energy collected by the corresponding angle of loss-free region, the sub-waveguide with small height Hi of cross-section has small energy collected by the corresponding angle of loss-free region, so the number of sub-waveguides with small height Hi of cross-section needs to be greater than the number of sub-waveguides with large height Hi of cross-section.

Therefore, in the embodiments of the present invention, the sub-waveguides 2 include multiple types, and the height of each type of sub-waveguide 2 is the same, wherein the height of the ith type of sub-waveguide 2 satisfies:

wherein, the parameter θ i is a predetermined angle selected in the observation visual angle range, namely, the light beam incident angle when the light just meets the lossless region, and is also the visual angle to be modulated corresponding to the sub-waveguide, and n is the optical refractive index of the sub-waveguide 2;

wherein, the height of the plurality of types of sub-waveguides 2 is inversely proportional to the number of the corresponding sub-waveguides 2, that is, the smaller the cross-sectional height Hi of the sub-waveguide, the larger the number.

In the embodiment shown in fig. 8, the optical waveguide unit 100 includes two types of

sub-waveguides

11, 12, the height H1 of the sub-waveguide 11 is greater than the height H2 of the sub-waveguide 12, and the number (1) of the sub-waveguides 11 is smaller than the number (2) of the sub-waveguides 12. In this way, the energy of different incident rays can be collected.

In the embodiment shown in fig. 9, the optical waveguide unit 100 includes three types of

sub-waveguides

11, 12, 13, the height H1 of the sub-waveguide 11 is the largest and the number is the smallest (1), the height H3 of the sub-waveguide 13 is the smallest and the number is the largest (2), and the height H2 of the sub-waveguide 12 satisfies H3 < H2 < H1, and the number is 2, so that the distribution of energy of three loss-free zone angles is realized by arranging three types of sub-waveguides respectively having three types of cross-sectional heights H in optical waveguide units 100, which can improve the uniformity of energy of the imaging light beam in the whole imaging view angle range.

Of course, the above embodiments with reference to fig. 8 and 9 are only optional examples according to the invention, i.e. arranged from large to small in height. The utility model discloses in do not restrict the order of arranging of specific sub-waveguide, the order of arranging of the sub-waveguide 2 of different cross section heights can be arranged for arbitrary order promptly, can be for arranging according to the height from small to big, can big before big after little again, perhaps also can big after little again earlier, all can not influence the distribution to energy under a plurality of incident ray angles.

According to the utility model discloses optical waveguide unit 100, through setting up the sub-waveguide of a plurality of heights, modulate to different visual angles under a plurality of heights respectively to can realize distributing the energy of a plurality of lossless district angles, thereby can improve the homogeneity of imaging beam at whole formation of image visual angle within range energy.

According to the utility model discloses an some embodiments, in order to prevent that optical waveguide array imaging quality from being influenced by diffraction, sub-waveguide 2's cross section height can not be too little, can be greater than 0.1mm, simultaneously, in order to improve optical waveguide array's the sharp formation of image of object point, sub-waveguide 2's cross section height H can not be too big, can be less than 5mm, that is to say, every sub-waveguide 2's cross section height H satisfies 0.1mm < H <5mm optionally, sub-waveguide 2's refracting index n > 1.46.

According to the utility model discloses an some embodiments, reflection element 1 is metal level 1a, as shown in fig. 10, metal level 1a can be metal material such as silver, aluminium, or chromium, 0.001mm < hm <0.1mm high hm of metal level 1a satisfies, metal level 1a can regard as the very high optical reflection face of finish, mainly play the reflection action and obstruct light effect, because bubble, impurity, dust etc. easily make the light scattering produce the parasitic light, can keep off receiving element such as this type of light entering detector or people's eye through metal level 1a, optionally, only include metal levels in the metal level 1 a.

According to the utility model discloses a some embodiments, reflection unit 1 can be total reflection layer 1b (as shown in fig. 11), and the material of total reflection layer 1b can be transparent optical material such as resin, glass, crystal, and its effect that can carry out reflection light through the mode of total reflection, and total reflection effect can make the reflection of incident light nearly lossless, improves the reflectivity of this aspect greatly the refracting index scope nei of total reflection layer 1b calculates through following formula:

wherein, the parameter θ ei is the maximum incident angle of the surface of the optical waveguide unit 100 when the total reflection condition is satisfied, and n is the optical refractive index of the sub-waveguide 2.

Optionally, the height H2 of the total reflection layer 1b satisfies 0.004mm < hr < (0.1H), where H is the height of the corresponding sub-waveguide 2 where the total reflection layer 1b is located, and the thickness of the total reflection layer is greater than 0.004mm, so as to avoid that the total reflection layer 1b fails because the thickness of the total reflection layer 1b is smaller than the penetration depth of the total reflection evanescent wave, and step is carried out, so that the thickness of the total reflection layer 1b is not too large, and the phenomenon that light enters the total reflection layer to cause light deflection caused by different refractive indexes of the total reflection layer and the optical waveguide layer, and the image definition is influenced is avoided.

According to the embodiments of the present invention, the reflection unit 1 is an interference type medium reflection layer 1c, as shown in fig. 11, the reflection characteristic is achieved by the way of transparent medium interference, so that the incident light is reflected, the reflectivity of the reflection film layer is higher than that of other metal film layers, and the reflectivity of the light can be greatly improved, the interference type medium reflection layer 1c can comprise or multiple layers of transparent medium films, 1/4 wavelength film and 1/2 wavelength film, wherein the optical thickness of the 1/4 wavelength film is 1/4 of the wavelength of the incident light, and the optical thickness of the 1/2 wavelength film is 1/2 of the wavelength of the incident light;

wherein the optical thickness T of the film layer is n_gL, wherein ng isThe refractive index of the film material, l is the thickness of the film.

The transparent medium may be magnesium fluoride, silicon oxide, silicon dioxide, or other crystal materials.

Optionally, the height hj of the dielectric reflective layer 1c satisfies: hj < (0.1h), where h is the height of the corresponding sub-waveguide 2 where the total reflection layer 1b is located.

According to the embodiments of the present invention, the reflective unit 1 is a combination of the metal layer 1a and the total reflective layer 1b, or the combination of the metal layer 1a and the dielectric reflective layer 1c, the side surface of the metal layer 1a facing the corresponding sub-waveguide 2 has a predetermined roughness, and/or the metal layer 1a is a metal film layer that is oxidized and blackened, in alternative examples, the side surface of the metal layer 1a facing the corresponding sub-waveguide 2 may be formed as a rough surface 11a having a predetermined roughness, as shown in fig. 12, for totally reflecting the light transmitted by the scattering layer 1b or the dielectric reflective layer 1c, in another alternative examples, the side surface of the metal layer 1a facing the corresponding sub-waveguide 2 may be provided as a metal film layer that is oxidized and blackened for absorbing the light transmitted by the total reflective layer 1b or the dielectric reflective layer 1 c.

Alternatively, in the reflection unit 1 of the present embodiment, when the metal layer 1a and the total reflection layer 1b are included, the total reflection layer 1b may further control an outgoing ray angle, and when an incident angle of an incident ray does not satisfy a total reflection condition of the total reflection layer 1b, the transmitted ray may reach the metal layer by the ray transmission of the total reflection layer 1b, be scattered or absorbed, and thus control an angular light outgoing, as shown in fig. 12.

With reference to fig. 11, flat lenses according to the third aspect of the present invention will be described, which include two transparent substrates 2000 and two

optical waveguide arrays

1000a, 1000b according to the above embodiments.

Each transparent substrate 2000 is provided with two optical surfaces, the optical surfaces are used for protecting the

optical waveguide arrays

1000a and 1000b, the two optical waveguide arrays are arranged between the two transparent substrates 2000 through viscose glue, the extending directions of the optical waveguides of the two optical waveguide arrays are orthogonally arranged, namely the extending directions of the optical waveguide units are mutually perpendicular, so that light beams converge at a point , an object image surface is ensured to be symmetrical relative to the equivalent negative-refractive-index flat lens, a negative-refractive-index phenomenon is generated, and imaging of the flat lens is realized.

Alternatively, the optical waveguide array and the transparent substrate 2000 may be bonded by a photosensitive adhesive or a thermal adhesive.

In the embodiments of the present invention, as shown in fig. 11, an antireflection film 210 is disposed on the optical surface of each transparent substrate 200 away from the optical waveguide array to further improve the imaging effect.

According to the utility model discloses planar lens adopts single-row multirow and the optical waveguide of cross section for the rectangle to constitute array structure, can make two-dimentional or three-dimensional light source directly realize real holographic image in the air, realizes the three-dimensional stereoscopic display characteristic of bore hole when imaging is effectual, in addition, through the optical waveguide unit that 2 range upon range of settings of sub-waveguide of a plurality of heights separated by reflection unit 1 formed, can promote formation of image visual angle homogeneity, improve user experience on the degree of journey.

In the description herein, reference to the terms " embodiments," " embodiments," "exemplary embodiments," "examples," "specific examples," or " examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least embodiments or examples of the invention.

While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

An optical waveguide unit of , comprising:

the reflecting units are the same in structure and are any or the combination of any two of a metal layer, a total reflecting layer and a dielectric reflecting layer;

the optical waveguide comprises a plurality of sub-waveguides which are arranged in a stacked mode, wherein reflection units are arranged on two sides of each sub-waveguide respectively, at least two of the heights of the sub-waveguides are different in the stacking direction of the sub-waveguides, and different height values of the sub-waveguides correspond to different incidence angle directions.
2. The optical waveguide unit of claim 1, wherein each of the sub-waveguides has a height in a range of 0.1mm to 5 mm.
3. The optical waveguide unit of claim 1, wherein the sub-waveguides have a refractive index n > 1.46.
4. The optical waveguide unit of claim 1, wherein the plurality of sub-waveguides includes a plurality of types, and the height of each types of sub-waveguides is the same, wherein the height of the i-th type of sub-waveguide satisfies:

wherein the parameter theta_iA predetermined angle is selected in the range of observation visual angles, n is the optical refractive index of the sub-waveguide, and W is the width of the sub-waveguide;

wherein the height of the plurality of types of sub-waveguides is inversely proportional to the number of corresponding sub-waveguides.
5. The optical waveguide unit of wherein the reflective elements are kinds of metal layers, metal layers and total reflective layers, metal layers and dielectric reflective layers.
6. The optical waveguide unit of claim 5, wherein the metal layer is made of silver, aluminum, or chromium, and a height hm of the metal layer satisfies: 0.001mm < hm <0.1 mm.
7. The optical waveguide unit according to claim 5, wherein when the reflection unit is a metal layer and a total reflection layer, or a metal layer and a dielectric reflection layer, an -side surface of the metal layer facing the corresponding sub-waveguide has a predetermined roughness, and/or

The metal layer is a blackened metal film layer.
8. The optical waveguide unit of any of claims 1-4, wherein the reflective element is a fully reflective layer having a refractive index range n_eiCalculated by the following formula:

wherein, the parameter θ ei is the maximum incident angle of the surface of the optical waveguide unit when the total reflection condition is satisfied, and n is the optical refractive index of the sub-waveguide.
9. The optical waveguide unit according to claim 8, wherein the height h2 of the total reflection layer satisfies: 0.004mm < hr < (0.1H), where H is the height of the corresponding sub-waveguide where the total reflection layer is located.
10. The optical waveguide unit of wherein the reflective unit is an interferometric dielectric reflective layer comprising or multiple layers of transparent dielectric films of the type 1/4 wavelength film, 1/2 wavelength film wherein the optical thickness of the layers of the 1/4 wavelength film is 1/4 the wavelength of the incident light and the optical thickness of the layers of the 1/2 wavelength film is 1/2 the wavelength of the incident light;

whereinThe optical thickness T ═ n of the film layer_gL, wherein n_gIs the refractive index of the film material, and l is the film thickness.
11. The optical waveguide unit of claim 10, wherein the height hj of the dielectric reflective layer satisfies: hj < (0.1H), wherein H is the height of the corresponding sub-waveguide where the total reflection layer is located.
12, optical waveguide array, comprising a plurality of optical waveguide units according to any of claims 1-11, each of the optical waveguide units having a rectangular cross section and a plurality of the optical waveguide units being joined in parallel;

the outer contour of the optical waveguide array is rectangular, and the extending direction of the optical waveguide unit and at least two sides of the outer contour of the optical waveguide array form an angle of 30-60 degrees.
13. The optical waveguide array of claim 12, wherein the optical waveguide units extend at an angle of 45 degrees to at least two sides of the outer profile of the optical waveguide array.
14. The optical waveguide array of claim 12, wherein the plurality of optical waveguide units are bonded together by an adhesive layer, the adhesive layer having a thickness greater than 0.001 mm.
A flat lens of the type 15, , comprising:

two transparent substrates, each of the transparent substrates having two optical surfaces;

two optical waveguide arrays according to of any of claims 12-14, the two optical waveguide arrays being arranged between the two transparent substrates by glue, and the optical waveguide extension directions of the two optical waveguide arrays being arranged orthogonally.
16. The plate lens of claim 15, wherein an optical surface of each transparent substrate distal from the optical waveguide array is provided with an antireflection film.