KR20200020630A - structured light projector based on meta-surface integrated light source - Google Patents

Abstract

According to an embodiment of the present invention, provided is a structured optical projector based on a meta-surface integrated light source, which comprises: a first conductivity type distributed reflective layer on a substrate; first electrodes on an edge of the first conductivity type distributed reflective layer; a quantum well layer disposed on the center of the first conductivity type distributed reflective layer between the first electrodes; a second conductivity type distributed reflective layer on the quantum well layer; second electrodes on an edge of the second conductivity type distributed reflective layer; an intensity modulation layer including a metal plate disposed on the second conductivity type distributed reflective layer between the second electrodes and having a plurality of holes, and oxide blocks in the holes; and a phase modulation layer having nitride blocks disposed on the oxide blocks of the intensity modulation layer.

Description

Structured light projector based on meta-surface integrated light source

The present invention relates to an optical projector, and more particularly to a metasurface integrated light source based structured optical projector.

In general, the non-contact three-dimensional shape measurement method having a depth resolution of several tens of micrometers to tens of millimeters is generally a time of flight (TOF) method for measuring the distance between a sensor and a subject, a stereo vision method using binocular vision, and a patterned method. The method may include a structured light method using an interference image by irradiating light. In the 3D sensing method using structured light, height information may be obtained by analyzing an interference fringe of a subject having a height by using a plurality of images projecting a patterned image onto a subject.

An object of the present invention is to provide a meta-surface integrated light source-based structured optical projector that can simultaneously control the intensity and phase of the laser light.

The present invention discloses a meta surface integrated light source based structured light projector according to the concept. Its structured light projector includes: a first conductivity type reflective reflection layer on a substrate; First electrodes on an edge of the first conductivity type distributed reflecting layer; A multi quantum well layer disposed on a center of the first conductivity type distributed reflecting layer between the first electrodes; A second conductivity type reflecting layer on the multi quantum well layer; Second electrodes on an edge of the second conductivity type distributed reflecting layer; An intensity modulation layer disposed on the second conductivity-type distributed reflecting layer between the second electrodes, the metal plate having a plurality of holes and an oxide block in the holes; And a phase modulation layer having nitride blocks disposed on the oxide block of the intensity modulation layer.

As described above, the metasurface integrated light source based structure optical projector according to an embodiment of the present invention may simultaneously control the intensity and phase of the laser light by using an intensity modulation layer and a phase modulation layer on the intensity modulation layer.

1 is a cross-sectional view illustrating a metasurface integrated light source based structure optical projector according to an exemplary embodiment of the present invention.
FIG. 2 is a diagram illustrating an intensity distribution of an electric field of the laser light of FIG. 1.
3 is a cross-sectional view illustrating an example of the meta structure of FIG. 1.
4 is a plan view illustrating an example of the intensity modulation layer of FIG. 2.
5 is bar graphs showing transmittance according to the wavelength of the laser light of FIG. 1.
6 is a plan view illustrating an example of the phase modulation layer of FIG. 3.
7 is a cross-sectional view illustrating an example of a buffer layer and a phase modulation layer of FIG. 3.
FIG. 8 is a diagram illustrating a phase delay characteristic according to the wavelength of the laser light of FIG. 1.
FIG. 9 is a graph showing phase retardation characteristics for a specific wavelength of the laser light of FIG. 1.
10A through 10C are plan views illustrating examples of the image of the laser light of FIG. 1.
11A to 11C are diagrams illustrating holographic phase information images of the laser light of FIG. 1.
12 is a diagram illustrating an example of a reconstructed image obtained from the phase information image of the holograms of FIGS. 11A to 11C.
FIG. 13 is a diagram illustrating another example of a reconstructed image obtained from the phase information image of the holograms of FIGS. 11A to 11C.
FIG. 14 is a diagram illustrating an example of a 3D image system using the metasurface integrated light source based structured light projectors of FIG. 1.
15A and 15B illustrate another example of a 3D image system using the metasurface integrated light source-based light projector of FIG. 1.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Advantages and features of the present invention, and methods for achieving them will be apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in different forms. Rather, the embodiments introduced herein are provided so that the disclosure may be made thorough and complete, and to fully convey the spirit of the invention to those skilled in the art, and the invention is defined only by the scope of the claims. Like reference numerals refer to like elements throughout the specification.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, 'comprises' and / or 'comprising' refers to a component, step, operation and / or element that is mentioned in the presence of one or more other components, steps, operations and / or elements. Or does not exclude additions. In addition, since it is in accordance with the preferred embodiment, reference numerals presented in the order of description are not necessarily limited to the order. In addition, in the present specification, where it is mentioned that a layer is on another layer or substrate, it means that it may be formed directly on the other layer or substrate or a third film may be interposed therebetween.

In addition, the embodiments described herein will be described with reference to cross-sectional views and / or plan views, which are ideal illustrations of the present invention. In the drawings, the thicknesses of films and regions are exaggerated for effective explanation of technical content. Accordingly, shapes of the exemplary views may be modified by manufacturing techniques and / or tolerances. Accordingly, embodiments of the present invention are not limited to the specific forms shown, but also include variations in forms produced by the manufacturing process. Thus, the regions illustrated in the figures have schematic attributes, and the shape of the regions illustrated in the figures is intended to illustrate a particular form of region of the device and not to limit the scope of the invention.

1 illustrates a metasurface integrated light source-based structured light projector 100 according to an embodiment of the present invention.

Referring to FIG. 1, the metasurface integrated light source based structure light projector 100 of the present invention may be a light source integrated complex modulated hologram structure light generator. For example, the metasurface integrated light source based structure optical projector 100 of the present invention may include a substrate 10, a first conductivity type reflective reflection layer (DBR) 20, a first electrode 30, a quantum well layer 40, Current regulating layer 50, second conductivity type reflective reflecting layer 60, second electrode 70, first protective layer 72, wiring layer 74, metastructure 80, and second protective layer 90 may be included.

The substrate 10 may include a silicon substrate. Alternatively, the substrate 10 may comprise a glass or dielectric plate.

The first conductivity type reflecting layer 20 may be disposed on the substrate 10. For example, the first conductivity type reflecting layer 20 may be an n-type distributed reflecting layer. For example, the first conductivity type reflective reflection layer 20 may be a laminate structure of titanium oxide and silica.

The first electrode 30 may be disposed on the edge of the first conductivity type reflective reflecting layer 20. The first electrode 30 may include a metal of Au, Ag, Cu, Al, or W.

The quantum well layer 40 may be disposed on the center of the first conductivity type reflective reflection layer 20. The quantum well layer 40 may be disposed in the first electrode 30. The quantum well layer 40 may acquire a gain of the laser light 110.

The current regulation layer 50 may be disposed on the edge of the quantum well layer 40. The current regulation layer 50 can regulate the current provided to the quantum well layer 40. For example, the current control layer 50 may include a compound semiconductor of group III-V or a compound semiconductor of II-VI.

The second conductivity type distribution reflecting layer 60 may be disposed on the center of the quantum well layer 40 and on the current control layer 50. The second conductivity type reflective reflection layer 60 may reflect a portion of the laser light 110 and transmit a portion of the laser light 110. The second conductivity type reflecting layer 60 may be a p-type distribution reflecting layer. For example, the second conductivity type reflective reflection layer 60 may be a laminate structure of titanium oxide and silica.

The second electrode 70 may be disposed on an edge of the second conductivity type reflective reflection layer 60. When a current is provided between the second electrode 70 and the first electrode 30, the laser light 110 generates a first conductivity type reflecting layer 20, a quantum well layer 40, and a second conductivity type distribution. It may be oscillated within the reflective layer 60. A first conductivity type distributed reflection layer (DBR) 20, a first electrode 30, a quantum well layer 40, a current regulation layer 50, a second conductivity type distributed reflection layer 60, and a second electrode ( 70 may be composed of a vertical surface emitting laser (VCSEL). For example, laser light 110 may include visible light having a wavelength of about 400 nm to about 700 nm.

The first protective layer 72 may cover the first conductivity type reflective reflection layer 20 and the first electrode 30. The first protective layer 72 may be disposed on sidewalls of the quantum well layer 40, the current regulation layer 50, the second conductivity type distributed reflection layer 60, and the second electrode 70. For example, the first protective layer 72 may comprise silicon nitride.

The wiring layer 74 may be disposed on the first protective layer 72. The wiring layer 74 may be connected to the second electrode 70.

The meta structure 80 may be disposed on the center of the second conductivity type distributed reflection layer 60. The meta structure 80 may be disposed in the second electrode 70. The meta structure 80 may have a negative refractive index. The meta structure 80 may control and / or modulate the intensity of the laser light 110.

FIG. 2 shows the intensity distribution of the electric field of the laser light 110 of FIG. 1.

1 and 2, laser light 110 may have circular intensity 102 and annular intensity 104. Circular intensity 102 may be disposed within annular intensity 104. Circular strength 102 may be greater than annular strength 104. The meta structure 80 can generate the circular intensity 102 of the laser light 110. Annular intensity 104 may be disposed outside of circular intensity 102. The laser light 110 outside the meta structure 80 may have an annular intensity 104.

Furthermore, the meta structure 80 may control and / or modulate the phase as well as the intensity of the laser light 110.

3 illustrates an example of the meta structure 80 of FIG. 1.

Referring to FIGS. 1 and 3, the meta structure 80 may include an intensity modulation layer 82, a buffer layer 84, and a phase modulation layer 86. The intensity modulation layer 82 may have a plate shape. The intensity modulating layer 82 may modulate the intensity of the laser light 110. The buffer layer 84 may be disposed on the intensity modulation layer 82. For example, buffer layer 84 may comprise silicon oxide. The buffer layer 84 may have a thickness of about 200 nm. Phase modulating layer 86 may be disposed on buffer layer 84. Phase modulating layer 86 may modulate the phase of laser light 110.

4 shows an example of the intensity modulation layer 82 of FIG. 2.

1, 3, and 4, the intensity modulation layer 82 may include a metal plate 81 and oxide blocks 83.

The metal plate 81 includes Au and may have a plurality of nano holes 85. The nano holes 85 may have an inner diameter of about 50 nm to about 150 nm. The nano holes 85 having the same inner diameter may be grouped as a plurality of cells.

The oxide blocks 83 may be disposed in the nano holes 85. Each of the oxide blocks 83 may have a refractive index of about 1.45. The oxide blocks 83 may include silicon oxide (SiO ₂ ). The oxide blocks 83 having the same size as each other may be grouped into a plurality of cells. For example, the oxide blocks 83 may be clustered into first to fourth cell blocks 83a, 83b, 83c, and 83d. Each of the first to fourth cell blocks 83a, 83b, 83c, and 83d may be configured as four. The first cell blocks 83a may have a first radius r1 of about 50 nm. The second cell blocks 83b may have a second radius r2 of about 75 nm. The third cell blocks 83c may have a third radius r3 of about 100 nm. The fourth cell blocks 83d may have a fourth radius r4 of about 125 nm. The oxide blocks 83 may control the intensity of the laser light 110 according to the first to fourth radiuses r1, r2, r3, and r4.

5 shows the transmittance according to the wavelength of the laser light 110 of FIG.

Referring to FIG. 5, the first cell blocks 83a of the first radius r1 have a transmittance of about 20% with respect to the laser light 110, and the second cell blocks of the second radius r2 ( 83b) has a transmission of about 50%, the third cell blocks 83c of the third radius r3 have a transmission of about 70%, and the fourth blocks 84d of the fourth radius r4 It may have a transmittance of about 80%.

Referring again to FIG. 3, phase modulating layer 86 may be selectively disposed on oxide blocks 83. Phase modulation layer 86 may have a dielectric constant higher than that of oxide blocks 83 and buffer layer 84. For example, phase modulating layer 86 may have a refractive index of about 2.3. As an example, the phase modulation layer 86 may include silicon nitride (Si ₃ N ₄ ).

FIG. 6 shows an example of the phase modulation layer 86 of FIG. 3. FIG. 7 shows one example of the buffer layer 84 and the phase modulation layer 86 of FIG. 3.

6 and 7, the phase modulation layer 86 may have a rod shape. Phase modulating layer 86 may have a radius of about 100 nm. Phase modulating layer 86 may have a thickness of about 200 nm.

FIG. 8 shows phase delay characteristics according to the wavelength of the laser light 110 of FIG. 1.

Referring to FIG. 8, the phase modulation layer 86 may delay the phase of the laser light 110. If the radius of phase modulating layer 86 increases above about 60 nm, the phase of laser light 110 may be delayed.

9 shows phase retardation characteristics for a particular wavelength of the laser light 110 of FIG. 1.

Referring to FIG. 9, a phase of the laser light 110 having a wavelength of about 633 nm may be controlled according to a radius of the phase modulation layer 86. When the radius of the phase modulation layer 86 is 65 nm (a), the phase of the laser light 110 may be delayed by about −2π / 3. When the radius of the phase modulation layer 86 is 82 nm (b), the phase of the laser light 110 may be delayed by about −π / 2. When the radius of the phase modulation layer 86 is 102 nm (c), the phase of the laser light 110 may be delayed by about −π / 3. When the radius of the phase modulation layer 86 is 115 nm (d), the phase of the laser light 110 may hardly be delayed.

10A-10C show examples of the image of the laser light 110 of FIG. 1.

10A through 10C, the laser light 110 may be implemented as unit images having a circular shape by the meta structure 80.

Referring to FIG. 10A, the meta structure 80 may include a laser light 110, and a design image of the unit hologram structured light may have a circular shape.

Referring to FIG. 10B, an amplitude image may be calculated from a design image of unit hologram structured light. The amplitude image may have a concentric shape. The amplitude image can be calculated from the real part of the complex number of laser light 110.

Referring to FIG. 10C, the phase image may be calculated from the imaginary part of the complex number of the laser light 110. The phase image may have a concentric shape.

11A-11C show holographic phase information images of the laser light 110 of FIG. 1.

11A to 11C, the phase information image of the hologram of the laser light 110 may include a phase information image, a left moving phase information image, and a right moving phase information image of the original image of the hologram. The phase information of the original image of FIG. 11A may have an information image of phase space in the upper right corner.

12 illustrates an example of a reconstructed image obtained from the phase information image of the holograms of FIGS. 11A to 11C.

Referring to FIG. 12, the phase shift image of the hologram may be corrected by about 10 degrees in the horizontal direction to move the transparent hologram reconstructed image from the predetermined position to the left or the right.

FIG. 13 shows another example of a reconstructed image obtained from the phase information image of the holograms of FIGS. 11A to 11C.

Referring to FIG. 13, the phase shift image of the hologram may be corrected by about 10 degrees in the vertical direction to move the perspective hologram reconstructed image up or down at a predetermined position.

FIG. 14 shows an example of a 3D image system using the metasurface integrated light source based structured light projectors 100 of FIG. 1.

Referring to FIG. 14, the plurality of metasurface integrated light source-based light projectors 100 may implement a 3D image system by irradiating the laser light 110 onto an object 200. The metasurface integrated light source based structure light projectors 100 on the left emit the first structured light 112 shifted to the left of the laser light 110, and the metasurface integrated light source based structure light projector 100 on the right side displays the laser light. The second structured light 114 that is moved to the right of the light 110 is irradiated, and the central metasurface integrated light source-based structured light projector 100 emits the phase shifted third structured light 116 of the laser light 110. You can investigate. The hologram may be displayed on the subject 200 by the first structure light 112, the second structure light 114, and the third structure light 116.

15A and 15B show another example of a 3D image system using the metasurface integrated light source based structure optical projector 100 of FIG. 1.

15A and 15B, the metasurface integrated light source infrastructure light projector 100 may provide the laser light 110 to the reflector 400. The laser light 110 may have a color by a color filter. The reflector 400 may reflect the laser light 110 to the camera 300. The camera 300 may receive the laser light 110 to implement an image on the reflector 400.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, a person of ordinary skill in the art may implement the present invention in other specific forms without changing the technical spirit or essential features of the present invention. You will understand that there is. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

Claims (1)

A first conductivity type reflective reflection layer on the substrate;
First electrodes on an edge of the first conductivity type distributed reflecting layer;
A quantum well layer disposed on a center of the first conductivity type reflective reflecting layer between the first electrodes;
A second conductivity type reflecting layer on said quantum well layer;
Second electrodes on an edge of the second conductivity type distributed reflecting layer;
An intensity modulation layer disposed on the second conductivity-type distributed reflecting layer between the second electrodes, the metal plate having a plurality of holes and an oxide block in the holes; And
And a phase modulation layer having nitride blocks disposed on the oxide block of the intensity modulation layer.

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