CN210348063U

CN210348063U - Nano waveguide lens and AR display device

Info

Publication number: CN210348063U
Application number: CN201921184611.0U
Authority: CN
Inventors: 李瑞彬; 罗明辉; 乔文; 李玲; 周振; 熊金艳
Original assignee: Suzhou University; SVG Tech Group Co Ltd
Current assignee: Suzhou University; SVG Tech Group Co Ltd
Priority date: 2019-07-25
Filing date: 2019-07-25
Publication date: 2020-04-17
Anticipated expiration: 2029-07-25

Abstract

A nanometer waveguide lens comprises a waveguide substrate, a dielectric film and a nanometer grating, wherein the dielectric film is arranged on the waveguide substrate, the nanometer grating is arranged on the dielectric film, an included angle is formed between the nanometer grating and the dielectric film, the refractive index of the waveguide substrate is the same as that of the nanometer grating, and the refractive index of the nanometer grating is larger than that of the dielectric film. The utility model discloses a nanometer waveguide lens's simple structure, thickness is little, and diffraction efficiency is high, the angle of vision is big to the response spectrum broad of nanometer grating, single piece lens can realize the colourization and show. The utility model also provides a AR display device.

Description

Nano waveguide lens and AR display device

Technical Field

The utility model relates to a show technical field, especially relate to a nanometer waveguide lens and AR display device.

Background

The AR (Augmented Reality) technology is a technology for calculating the position and angle of a camera image in real time and adding a corresponding image, and the purpose of the technology is to overlap a virtual world on a screen in the real world and perform interaction. The technology of seamlessly integrating the real world information and the virtual world information is realized, the real world information is displayed, the virtual information is displayed at the same time, and the two kinds of information are mutually supplemented and superposed to present a new environment with richer perception effect to a user. The method has great potential application value in various fields, such as industrial manufacturing and maintenance fields, medical fields, military fields, entertainment and game fields, education fields and the like.

Common optical solutions for AR lenses are:

1. prism reflection: the light emitted by the display is reflected from the lens into the human eye by using a common angle prism, and meanwhile, the light of the real world is transmitted. The method is simple and convenient, but the field angle can only be about 20 degrees due to technical limitation, and the field angle can only be improved by thickening the lens. The light rays pass through the semi-transparent semi-reflective film layer twice in sequence, so that the light energy utilization rate is low (about 20 percent), and the picture is dark; the free-form surface prism can improve the problems, light rays are converted by the non-rotational symmetrical XY polynomial free-form surface prism to form a virtual amplified image, and the total reflection emergent surface and the total reflection surface can eliminate aberration such as chromatic aberration, distortion and the like, so that the imaging quality is clearer, the visual angle can reach 54 degrees, and the visual angle can be further improved by adopting the double free-form surface prisms. The disadvantages are that the volume is large, the thickness is about 7 to 10mm, the surface shape can not be continuously processed, and the design difficulty is large.

2. Array optical waveguide: lumus is designed by adopting an array grating waveguide, a semi-transparent and semi-reflective process is carried out on coupled light for several times, and transmitted light enters human eyes to realize augmented reality display. Similar to a periscope, except that a plurality of reflective sheets are used to expand the exit pupil, each reflective sheet reflects parallel light to form the same image.

The representative product of this device, PD-18 resolution 800X 600, 26 degree angle of view 20 degree, 10mm exit pupil, 23mm exit pupil distance, 2.3mm thickness of the device, weight less than 70g, and 70% transmittance in the display area is used by Lumus corporation. The method has low technical barrier, but adopts multi-piece gluing in the process, and the mass production cost is higher.

3. Diffractive light waveguide: the micro-display device mainly comprises a micro-display, a grating and a flat waveguide. The image of the micro display is changed into parallel light after passing through the micro collimating lens, the parallel light enters the optical waveguide and reaches the first grating, and the parallel light changes the transmission direction due to the diffraction effect of the grating, so that the parallel light can be transmitted along the optical waveguide without loss when the total reflection condition is met. When the parallel light is transmitted to the second grating, the total reflection condition is destroyed so that the parallel light exits from the grating and enters human eyes for imaging. Due to the presence of the grating and the waveguide, the optical image can propagate with vertical deflection. This not only reduces the propagation distance, but also keeps the center of gravity of the optical system within the head. For example, Hololens couples an image on LCOS to an optical waveguide through three holographic gratings, transmits the image through three optical waveguides, and finally couples and outputs the image through corresponding holographic gratings right in front of human eyes to project the image to the human eyes, and realizes color projection in a manner of multilayer optical waveguides.

In conjunction with the above analysis, the disadvantages of the prior art include: the response spectrum of the diffraction grating is narrow; the colorful display is realized by superposing 3 or more lenses, and the lens is thicker.

The foregoing description is provided for general background information and is not admitted to be prior art.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a nanometer waveguide lens and AR display device, simple structure, thickness is little, and diffraction efficiency is high, the angle of vision is big to the response spectrum broad of nanometer grating, single piece lens can realize the colourization and show.

A nanometer waveguide lens comprises a waveguide substrate, a dielectric film and a nanometer grating, wherein the dielectric film is arranged on the waveguide substrate, the nanometer grating is arranged on the dielectric film, an included angle is formed between the nanometer grating and the dielectric film, the refractive index of the waveguide substrate is the same as that of the nanometer grating, and the refractive index of the nanometer grating is larger than that of the dielectric film.

Further, the included angle is 15-30 degrees.

Further, the refractive index of the waveguide substrate is 1.7-2.0.

Further, the dielectric film has a refractive index of 1.3 to 1.6 and a thickness of 50 to 500 nm.

Further, the period of the nano-grating is 400-450nm, the height of the nano-grating is greater than 330nm, and the duty ratio is 0.3-0.6.

The utility model also provides a AR display device, including above-mentioned nanometer waveguide lens.

The nano waveguide lens comprises a waveguide substrate, a dielectric film and a nano grating, and has simple structure and small thickness; the nano-grating and the dielectric film form an included angle, the refractive index of the waveguide substrate is the same as that of the nano-grating, the refractive index of the nano-grating is larger than that of the dielectric film, and the specific parameters of the waveguide substrate, the dielectric film and the nano-grating are combined within a certain range of the included angle, so that the nano-waveguide lens has the characteristics of high diffraction efficiency and large field angle; and the response spectrum of the nano grating is wider, the coverage of each wavelength is good, and the single lens can realize colorful display.

Drawings

Fig. 1 is a schematic cross-sectional view of a nano-waveguide lens according to an embodiment of the present invention.

Fig. 2 is a schematic diagram of the relationship between-1 order diffraction efficiency and wavelength of a nano-waveguide lens according to an embodiment of the present invention.

Fig. 3 is a schematic diagram illustrating a relationship between-1 st order diffraction efficiency and light incident angle of a nano-waveguide lens according to an embodiment of the present invention when the wavelength of incident light is 450 nm.

Fig. 4 is a schematic diagram illustrating a relationship between-1 st order diffraction efficiency and light incident angle of a nano-waveguide lens according to an embodiment of the present invention when the wavelength of incident light is 550 nm.

Fig. 5 is a schematic diagram of the relationship between the-1 st order diffraction efficiency and the light incident angle of the nano-waveguide lens according to an embodiment of the present invention when the wavelength of the incident light is 650 nm.

Detailed Description

The following detailed description of the embodiments of the present invention is provided with reference to the accompanying drawings and examples. The following examples are intended to illustrate the invention, but are not intended to limit the scope of the invention.

Fig. 1 is a schematic cross-sectional view of a nano-waveguide lens according to an embodiment of the present invention. As shown in fig. 1, the nano waveguide lens 10 includes a waveguide substrate 12, a dielectric film 13 and a nano grating 14, the dielectric film 13 is disposed on the waveguide substrate 12, the nano grating 14 is disposed on the dielectric film 13, the nano grating 14 and the dielectric film 13 form an included angle 101, specifically, the included angle 101 is 15 ° to 30 °, the refractive index of the waveguide substrate 12 is the same as that of the nano grating 14, and the refractive index of the nano grating 14 is greater than that of the dielectric film 13.

In the present embodiment, the refractive index of the waveguide substrate 12 is 1.7-2.0, and specifically, the material of the waveguide substrate 12 may be a glass material, but is not limited thereto. The dielectric film 13 has a refractive index of 1.3-1.6 and a thickness of 50-500nm, and specifically, the dielectric film 13 may be magnesium fluoride or aluminum fluoride, but not limited thereto. The period of the nano-grating 14 is 400-450nm, the height thereof is greater than 330nm, and the duty cycle is 0.3-0.6, specifically, the material of the nano-grating 14 may be a glass material, but not limited thereto. Therefore, by combining the above conditions and the structure of the nano waveguide lens 10 itself, the nano waveguide lens 10 of the present invention has the characteristics of high diffraction efficiency and large field angle.

Fig. 2 is a schematic diagram of the relationship between-1 order diffraction efficiency and wavelength of a nano-waveguide lens according to an embodiment of the present invention. As shown in fig. 2, the abscissa represents wavelength and the ordinate represents diffraction efficiency. When the wavelength range is 400-650nm, the change of the diffraction efficiency is relatively smooth, and the diffraction efficiency is higher and is greater than 0.5, when the wavelength is greater than 650nm, the diffraction efficiency begins to gradually decrease, and the lowest value of the diffraction efficiency is greater than 0.2 in the range of 400-700 nm. Therefore, the utility model discloses a nanometer waveguide lens 10's diffraction efficiency is high, and nanometer grating 14's response spectrum broad has the higher wavelength range broad of diffraction efficiency promptly. In this embodiment, the test conditions of fig. 2 are: the period of the nano-grating 14 is 440nm, the height is 400nm, the included angle 101 between the nano-grating 14 and the dielectric film 13 is 20 degrees, the duty ratio is 0.45, the refractive index is 1.9, the thickness of the dielectric film 13 is 100nm, the refractive index is 1.4, and the incident angle of incident light is 8 degrees.

Fig. 3 is a schematic diagram illustrating a relationship between-1 st order diffraction efficiency and light incident angle of a nano-waveguide lens according to an embodiment of the present invention when the wavelength of incident light is 450 nm. Fig. 4 is a schematic diagram illustrating a relationship between-1 st order diffraction efficiency and light incident angle of a nano-waveguide lens according to an embodiment of the present invention when the wavelength of incident light is 550 nm. Fig. 5 is a schematic diagram of the relationship between the-1 st order diffraction efficiency and the light incident angle of the nano-waveguide lens according to an embodiment of the present invention when the wavelength of the incident light is 650 nm. Fig. 3 to 5 were all measured under the same conditions, and as shown in fig. 3 to 5, the abscissa indicates the light incident angle and the ordinate indicates the diffraction efficiency, and it can be seen that, when the angle of view is calculated with 40% reduction in diffraction efficiency, the angle of view is 29 ° for the incident light wavelength of 450nm, 31 ° for the incident light wavelength of 550nm, and 26 ° for the incident light wavelength of 650 nm. Therefore, the angle of view of the nano-waveguide lens 10 of the present invention is large.

The nano waveguide lens 10 of the utility model comprises a waveguide substrate 12, a dielectric film 13 and a nano grating 14, and has simple structure and small thickness; an included angle 101 is formed between the nano-grating 14 and the dielectric film 13, the refractive index of the waveguide substrate 12 is the same as that of the nano-grating 14, the refractive index of the nano-grating 14 is larger than that of the dielectric film 13, and the specific parameters of the waveguide substrate 12, the dielectric film 13 and the nano-grating 14 are combined within a certain range of the included angle 101, so that the nano-waveguide lens 10 has the characteristics of high diffraction efficiency and large field angle; moreover, the response spectrum of the nano grating 14 is wide, the coverage of each wavelength is good, and the single lens can realize colorful display.

The utility model also provides a AR display device, including above-mentioned nanometer waveguide lens 10.

In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity. It will be understood that when an element such as a layer, region or substrate is referred to as being "formed on," "disposed on" or "located on" another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly formed on" or "directly disposed on" another element, there are no intervening elements present.

In this document, the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", "vertical", "horizontal", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for the sake of clarity and convenience of description of the technical solutions, and thus, should not be construed as limiting the present invention.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

As used herein, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, including not only those elements listed, but also other elements not expressly listed.

The above description is only for the specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto, and any person skilled in the art can easily think of the changes or substitutions within the technical scope of the present invention, and all should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A nanometer waveguide lens is characterized by comprising a waveguide substrate, a dielectric film and a nanometer grating, wherein the dielectric film is arranged on the waveguide substrate, the nanometer grating is arranged on the dielectric film, an included angle is formed between the nanometer grating and the dielectric film, the refractive index of the waveguide substrate is the same as that of the nanometer grating, and the refractive index of the nanometer grating is larger than that of the dielectric film.

2. The nanowaveguide lens of claim 1, wherein the included angle is between 15 ° and 30 °.

3. The nanowaveguide lens of claim 1, wherein the refractive index of the waveguide substrate is in the range of 1.7 to 2.0.

4. The nano-waveguide lens of claim 1, wherein the dielectric film has a refractive index of 1.3 to 1.6 and a thickness of 50 to 500 nm.

5. The nano waveguide lens as in claim 1, wherein the period of the nano grating is 400-450nm, the height is greater than 330nm, and the duty cycle is 0.3-0.6.

6. An AR display device comprising the NanoW lens of any one of claims 1 to 5.