3D light field detector, sensor and manufacturing method thereof

Abstract

The present disclosure relates to a light field detector for converting a vector of electromagnetic radiation into a color output, comprising at least one orientation detector on a transparent substrate, and the at least one orientation detector comprising at least two luminescent nanocrystal pixels having different emission wavelengths relative to each other. The present disclosure also relates to a light field sensor comprising a light field detector thereof and a method of manufacturing a light field detector.

Description

Technical Field

[0001] Generally speaking, the present invention relates to 3D light field detectors, sensors and methods of making the same. Background Art

[0002] Although advances in materials and semiconductor processes have revolutionized the design and fabrication of micro / nano photodetectors, the pixels of most sensors can only detect the intensity of electromagnetic waves. As a result, all phase information of the object and diffracted light waves is lost. While intensity information alone is sufficient for conventional applications such as two-dimensional (2D) photography and microscopy, this limitation hinders three-dimensional (3D) or even four-dimensional (4D) imaging applications such as high-resolution phase contrast imaging, light detection and ranging (LiDAR), autonomous vehicles, virtual reality, and space exploration. Typically, light fields representing phase information are measured by combining bulky optical elements such as microlens arrays or photonic crystals with pixelated photodiodes. However, integrating these elements into complementary metal oxide semiconductor architectures is expensive and complex. Optical resonances in subwavelength semiconductor structures offer the possibility of developing angle-sensitive structures by manipulating light-matter interactions. However, most of them are wavelength- or polarization-dependent and require high-refractive-index materials. In addition, the detection and control of light field vectors are currently limited to the ultraviolet and visible wavelength ranges. While some sensor systems based on Shack-Hartmann or Hartmann structures can be used in the EUV range, in situ measurements of hard X-rays and gamma rays remain a formidable challenge because these high-energy beams cannot be focused by conventional mirrors and microlenses.

[0003] It would be desirable to overcome or ameliorate at least one of the problems discussed above. Summary of the invention

[0004] A light field detector for converting a vector of electromagnetic radiation into a color output is disclosed, comprising at least one position detector on a transparent substrate, and the at least one position detector comprises at least two luminescent nanocrystal pixels having different emission wavelengths relative to each other.

[0005] The light field detector may comprise at least two of said position detectors oriented perpendicularly to each other.

[0006] In some embodiments, the light field detector includes at least three position detectors configured to cooperate to convert the vector of electromagnetic radiation into CIE XYZ tristimulus values. In this way, the combined color output from the three position detectors enables the absolute position of the light source to be determined.

[0007] In some embodiments, the light field detector includes at least three azimuth detectors, wherein the at least three azimuth detectors are oriented such that a first azimuth detector and a second azimuth detector are parallel to each other and a third azimuth detector is substantially perpendicular to the first azimuth detector and the second azimuth detector.

[0008] In some embodiments, the at least two light-emitting nanocrystal pixels are parallel to each other.

[0009] In some embodiments, the emission wavelength corresponds to red, green, or blue.

[0010] In some embodiments, the at least two light-emitting nanocrystal pixels are three light-emitting nanocrystal pixels. The three light-emitting nanocrystal pixels can be stacked together so that they form a semi-cylindrical configuration or a rectangular pyramid configuration.

[0011] In some embodiments, the light-emitting nanocrystal pixels include perovskite nanocrystals, ZnS:Cu 2+ / Mn 2+ 、SrAl 2 O 4 :Eu 2+ / Dy 3+ Phosphors, upconversion nanoparticles, black phosphorus, or a combination thereof.

[0012] In some embodiments, the perovskite nanocrystals are CsPbX 3 , wherein X is selected from Cl, Br and / or I.

[0013] In some embodiments, the perovskite nanocrystals are characterized by an emission wavelength of about 445 nanometers, about 523 nanometers, or about 652 nanometers.

[0014] In some embodiments, each position detector is characterized by a size of about 1 x 1 square micrometer to about 200 x 200 square micrometers.

[0015] In some embodiments, the 3D light field detector is characterized by an angular change detection limit of less than 0.015°.

[0016] In some embodiments, the light field detector is characterized by a density of position detectors of about 80 position detectors per square millimeter to about 200 position detectors per square millimeter.

[0017] In some embodiments, the transparent substrate is a polymer substrate, or preferably PDMS.

[0018] In some embodiments, the electromagnetic radiation has a wavelength of about 0.002 nanometers to about 500 nanometers.

[0019] The present invention also provides a 3D light field sensor, comprising:

[0020] a) a 3D light field detector as disclosed herein; and

[0021] b) A color charge coupled device (CCD) electromagnetically coupled to a 3D light field detector for converting the color output into an electrical signal.

[0022] In some embodiments, the light field sensor further includes a computer system configured to convert the electrical signal into spatial coordinates in a three-dimensional Cartesian coordinate system.

[0023] In some embodiments, the sensor is characterized by having an accuracy of approximately 0.5 mm at a distance of approximately 0.5 meters.

[0024] In some embodiments, the sensor is characterized by a spatial sampling density of about 300 points per square millimeter to about 600 points per square millimeter.

[0025] Also disclosed is a method of manufacturing a light field detector, comprising:

[0026] a) forming or positioning at least one position detector on a transparent substrate,

[0027] Therein, each position detector includes at least two luminescent nanocrystal pixels having different emission wavelengths relative to each other.

[0028] In some embodiments, the step of forming or positioning at least one position detector includes photolithographically patterning at least two light-emitting nanocrystal pixels in a silicon template and curing a polymer over the at least two light-emitting nanocrystal pixels to form a transparent substrate.

[0029] In some embodiments, the step of forming or positioning at least one position detector further comprises: photolithographically patterning a third light-emitting nanocrystal pixel in another silicon template and adhering it to the transparent substrate having the at least two light-emitting nanocrystal pixel patterns.

[0030] In some embodiments, each of the at least two luminescent nanocrystal pixels comprises nanocrystals dispersed in a polymer matrix.

[0031] In some embodiments, the at least two luminescent nanocrystal pixels are each independently characterized by a nanocrystal density of about 0.001 mol / ml to about 0.01 mol / ml.

[0032] Forming or positioning at least one position detector on a transparent substrate can include arranging the position detectors on the transparent substrate so that each position detector is oriented perpendicular to an adjacent position detector, wherein each position detector includes at least two luminescent nanocrystal pixels having different emission wavelengths relative to each other.

[0033] In some embodiments, the step of arranging the position detector includes photolithographically patterning at least two light-emitting nanocrystal pixels in a silicon template and curing a polymer over the at least two light-emitting nanocrystal pixels to form a transparent substrate.

[0034] In some embodiments, the step of arranging the position detector further comprises photolithographically patterning a third luminescent nanocrystal pixel in another silicon template and adhering it to the transparent substrate having the at least two luminescent nanocrystal pixel patterns. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Embodiments of the invention will now be described, by way of non-limiting examples, with reference to the accompanying drawings, in which:

[0036] Figure 1 Detection of X-rays to visible light fields using pixelated perovskite nanocrystal arrays is shown. a. Design of a 3D light field sensor based on pixelated color coding. The light field sensing pixels consist of patterned perovskite nanocrystals on a transparent film, converting light from different directions into luminescent signals of different colors, which can be detected by a color CCD. b. Working principle of light field sensing according to color coding. The basic unit of a 3D light field sensor is a single azimuth detector comprising multi-color emitting perovskite nanocrystals. The color of the output luminescence depends on the angle α between the incident light and the reference plane. Two vertically arranged azimuth detectors can realize 3D light field sensing and determine the azimuth angle of the incident light in a spherical coordinate system. In an arrangement with three azimuth detectors, the three azimuth angles α encoded in the color outputs of the three azimuth detectors are 1 , α 2 and α 3 The correlation of α and α enables the detection of the absolute position (x, y, z) of the light source. c. The chromaticity response of a single azimuth detector under light incidence from 0° to 360° relative to the reference plane. The red, blue, and black dots correspond to the three azimuth angles α. 1 , α 2 and α 3 , recorded using the three position detectors shown in (b). d. Relative to ZnS:Cu 2+ / Mn 2+ and SrAl 2 O 4 :Eu 2+ / Dy3+ The chromaticity response of a single perovskite nanocrystal-based azimuth detector for light incidence from 0° to 360°, compared to a control group of phosphors.

[0037] Figure 2 shows the characterization of pixelated color coding for 3D light field sensing. a. Chromatic response of single azimuth detectors composed of three-, four-, and five-color perovskite nanocrystals to the direction of incident light. b. CIE tristimulus values ​​X, Y, and Z of the output luminescence of a single azimuth detector as a function of the direction of incident light. c. Azimuthally resolved measurement of visible light (405 nm) using a single azimuth detector, with a minimum detectable angular change of 0.0018°. d. Measurement of the luminescence from different azimuth angles using two perpendicularly aligned azimuth detectors. Two types of color maps recorded for light incident at an angle θ and an elevation angle θ. e. Contours extracted from the two color maps in (d). By combining the color values ​​from the two azimuth detectors, a unique direction of incidence can be determined. f. Top view of an azimuth detector array for imaging a 3D light field, where adjacent pixels of perovskite nanocrystals are vertically aligned. The two detectors circled by yellow ellipses can determine the angle of the light beam incident on the center point of the ellipses. The inset depicts a side view of the patterned pixels. g. Photograph of a 3D light field sensor fabricated by integrating a perovskite nanocrystal array into a color CCD. The inset shows a portion of a microscope image of a nanocrystal-based azimuth detector.

[0038] Figure 3 shows 3D imaging of real scenes by pixelated color coding. a. Schematic diagram of the experimental setup. Multi-line structured light is incident on the object, and lenses 1 and 2 capture the reflected light and pass it to the perovskite nanocrystal array. The color CCD then measures the color of each azimuth detector to calculate the corresponding distance to the scene. b. Representative images of the perovskite nanocrystal array under incident light from different directions. c. Depth accuracy given by the standard deviation of repeated depth measurements and plotted as a function of scene depth and radial position in the field of view. A movable white flat screen is used as the target object. df. 3D images of the scene placed at 0.7 m, 1.5 m, and 3 m, respectively.

[0039] Figure 4 shows the wavefront imaging of X-rays (0.089 nm) and visible light (405 nm) by pixelated color coding. a. Principles of the Hartmann or Shack-Hartmann wavefront imaging method (top) and the wavefront imaging method based on a 3D light field sensor array (bottom). (b and c) Measurements of the divergent wavefront of X-rays at 14 mm and 20 mm from the X-ray source, respectively. (d and e) When the lens is at (F x =0°, F y =20°) and (Fx =30°, F y =40°) field of view is illuminated by visible light, the wavefront measured on the image plane. x and F y denote the field angles of the illumination beam in the X and Y directions, respectively. The focal length and aperture of the lens are 60 mm and 25.4 mm, respectively.

[0040] Figure 5 A schematic diagram showing the fabrication process of pixelated perovskite nanocrystal arrays.

[0041] Figure 6 shows examples of raw color images taken at different incident angles. When θ increases from -40° to 40°, and When θ increases from -40° to 40°, and , the blue color of the pixels in the red square gradually weakens.

[0042] Figure 7 The experimental setup for 3D imaging is shown. The light is collimated and extended to the grating by a combination of a collimator and a beam expander to generate a multi-line structured light source (405 nm, Shenzhen Infrared Laser Technology Co., Ltd.). The objective lens consisting of a lens 1 with a focal length of 100 mm and a lens 2 with a focal length of 25 mm collects the light reflected by the object and transmits it to a 3D light field sensor including a perovskite nanocrystal array.

[0043] Figure 8 The experimental setup and results of spherical wavefront measurement using perovskite nanocrystal arrays are shown. a. Experimental setup for wavefront measurement based on perovskite nanocrystal imaging array. b. Wavefronts measured at z=5 mm, 6 mm, 7 mm, and 8 mm, respectively.

[0044] Fig. 9 The geometric model of the 3D imaging system based on the triangulation method is shown.

[0045] Fig.10 A 2D geometrical schematic diagram of the designed imaging system is shown.

[0046] Fig.11 A schematic diagram showing the calibration of a multi-line structured light source. DETAILED DESCRIPTION

[0047] Light field detection is a technique that captures both the intensity and precise direction of light in free space. However, current light field detection techniques either require complex microlens arrays or are limited to the UV-visible wavelength range. The present invention provides a scalable method based on lithographically patterned perovskite nanocrystal arrays that can determine the radiation vector of incident rays in the wavelength range from X-rays to visible light (0.002-700 nanometers). Multicolor emitting perovskite nanocrystals can convert light from a specific direction into a pixelated color output with an angular resolution of 0.0018°, which is two orders of magnitude higher than conventional angle-sensing photodetectors. By modifying the nanocrystal array with a specific orientation, spatial localization of the light source and 3D light field detection can be performed. By combining the pixelated perovskite nanocrystal array with a color charge-coupled device, the effectiveness of 3D object imaging and visible light / X-ray wavefront imaging has been verified. The ability to image light fields beyond optical wavelengths through color contrast encoding can open up new applications from 3D phase contrast imaging to robotics, virtual reality, tomographic bioimaging, and satellite autonomous navigation.

[0048] Inspired by the versatility of color coding in data visualization, the inventors hypothesized that color contrast coding could be used to visualize the direction of light. To test this hypothesis, inorganic perovskite nanocrystals were selected as candidate materials because of their excellent optoelectronic properties. Under X-ray or visible light irradiation, they also exhibit efficient and tunable emission, as well as high color saturation across the visible spectral range. The basic design of 3D light field detection involves photolithographic patterning of perovskite nanocrystals on a transparent substrate ( Figure 1 a). A 3D light field sensor can then be constructed by integrating the patterned film substrate with a color charge-coupled device (CCD) that converts the angle of incident light into a specific color output.

[0049] The basic unit of a light field detector or 3D light field sensor is a single azimuth detector comprising a multi-color emitting perovskite nanocrystal. Since the absorption of light or radiation by the patterned nanocrystal changes with the incident direction of the light, there is a mapping between the luminescent color and the azimuth angle of the excitation light. When incident light shines on the patterned nanocrystal, the azimuth angle α ( Figure 1 b) Specifically, two azimuth detectors arranged perpendicular to each other can realize 3D light direction sensing and determine the azimuth angle of the incident light in spherical coordinates and elevation angle θ. In order to determine the absolute position of the light source, three azimuth detectors can be arranged to be encoded in the color output for the three corresponding azimuth angles α 1 , α 2 and α 3 Establish correlation between them.

[0050] In a three-dimensional Cartesian coordinate system, two detectors (A and B) are perpendicular to the XOY plane at coordinates (b, 0, 0) and (0, 0, 0), while a third detector (C) is arranged parallel to the XOY plane along the Y axis. Assuming the X axis is the reference direction, the projection of the light source or radiation source S on the XOY plane is S', and the angle between the line (connecting S' and detector A) and the reference direction is α 1 , the angle between the line (connecting S′ and detector B) and the reference direction is α 2 The angle between the line (connecting S and detector C) and the XOY plane is α 3 α 1 , α 2 and α 3 They are determined by the emission colors of the position detectors A, B and C. Therefore, the spatial position (x, y, z) of the source S can be solved by the following formula:

[0051]

[0052] Thus, the present invention provides a 3D light field detector for converting a vector of electromagnetic radiation into a color output, comprising at least one azimuth detector on a transparent substrate, the at least one azimuth detector comprising at least two luminescent nanocrystal pixels having different emission wavelengths relative to each other.

[0053] The light field detector may comprise at least two of said position detectors oriented perpendicularly to each other.

[0054] In some embodiments, the light field detector includes at least three azimuth detectors configured to cooperate with each other to convert the vector of electromagnetic radiation into CIE XYZ tristimulus values. The CIE color model is a mapping system that uses tristimulus values ​​(a combination of three color values ​​close to red / green / blue) that are plotted on a 3D space. When these values ​​are combined together, they can reproduce any color that the human eye can perceive. In this way, the combined color output from the three azimuth detectors enables the absolute position of the light source to be determined.

[0055] In some embodiments, at least three orientation detectors are oriented such that a first orientation detector and a second orientation detector are parallel to each other, and a third orientation detector is substantially perpendicular to the first orientation detector and the second orientation detector.

[0056] In some embodiments, the light field detector comprises an array of position detectors on a transparent substrate, each position detector being oriented perpendicular to adjacent position detectors; wherein each position detector comprises at least two luminescent nanocrystal pixels having different emission wavelengths relative to each other.

[0057] In some embodiments, the light field detector comprises an array of position detectors on a transparent substrate, wherein each position detector is in the same orientation relative to another position detector.

[0058] In some embodiments, the at least two luminescent nanocrystal pixels are parallel to each other. In other embodiments, the at least two luminescent nanocrystal pixels are arranged at an angle relative to each other. The angle may be less than 90°, or less than 45°.

[0059] Each luminescent nanocrystal pixel is configured to emit a wavelength of a specific color. At least two luminescent nanocrystal pixels are configured to emit wavelengths that are different from each other. In some embodiments, the emission wavelengths each correspond to red, green, or blue. In some embodiments, the emission wavelengths correspond to at least two colors selected from red, green, or blue. Other colors may also be used.

[0060] In certain embodiments, at least two luminescent nanocrystal pixels are three luminescent nanocrystal pixels. These three luminescent nanocrystal pixels can be stacked together so that they form a semi-cylindrical configuration or a rectangular pyramid configuration. In this respect, each luminescent nanocrystal pixel is configured so that it has a rectangular form or forms a part for a cylinder.

[0061] Each luminescent nanocrystal pixel includes a plurality of nanocrystals. Each luminescent nanocrystal pixel includes a specific type of nanocrystal or a combination thereof to have an emission wavelength of a specific color. By combining luminescent nanocrystal pixels that are each separate and different nanocrystals or nanocrystals in different proportions, these luminescent nanocrystal pixels can each emit light of a different wavelength when excited. In some embodiments, the luminescent nanocrystal pixels include perovskite nanocrystals, ZnS:Cu 2+ / Mn 2+ 、SrAl 2 O 4 :Eu 2+ / Dy 3+ Phosphors, upconversion nanoparticles, black phosphorus, or combinations thereof. In some embodiments, the luminescent nanocrystal pixels include perovskite nanocrystals. In some embodiments, the luminescent nanocrystal pixels include isotropic nanocrystals.

[0062] In some embodiments, the perovskite nanocrystals are CsPbX 3 , wherein X is selected from Cl, Br and / or I. For example, the perovskite nanocrystals may be CsPbBr 3 and / or CsPbCl 3 .

[0063] In certain embodiments, nanocrystals are characterized in that their particle size is about 10 nanometers to about 50 nanometers. In other embodiments, the particle size is about 10 nanometers to about 40 nanometers, about 10 nanometers to about 30 nanometers or about 10 nanometers to about 20 nanometers. In other embodiments, the particle size is about 20 nanometers.

[0064] In some embodiments, the perovskite nanocrystals (and therefore the light-emitting nanocrystal pixels) are characterized by an emission wavelength of about 445 nanometers, about 523 nanometers, or about 652 nanometers. The wavelength may vary depending on the color selected.

[0065] In some embodiments, each position detector is characterized by a size of about 1×1 square micron to about 200×200 square microns, or about 1×1 square micron to about 100×100 square microns. The size of the position detector is the accumulation of luminescent nanocrystal pixels.

[0066] In some embodiments, the position detectors are spaced from about 5 microns to about 20 microns apart from each other. In other embodiments, the spacing is from about 5 microns to about 18 microns, from about 5 microns to about 16 microns, from about 5 microns to about 14 microns, from about 5 microns to about 12 microns, from about 5 microns to about 10 microns, from about 5 microns to about 8 microns, or from about 5 microns to about 7 microns.

[0067] In some embodiments, the position detectors are characterized by a position detector density of about 80 position detectors per square millimeter to about 200 position detectors per square millimeter. In other embodiments, the position detector density is about 100 position detectors per square millimeter.

[0068] In some embodiments, the 3D light field detector is characterized by an angular change detection limit of less than 0.015° or less than 0.003° or preferably about 0.0018°. The angular change detection limit is the vector sensitivity.

[0069] In some embodiments, the transparent substrate is a polymer substrate, or preferably PDMS.

[0070] In some embodiments, the electromagnetic radiation has a wavelength of about 0.002 nanometers to about 700 nanometers, or about 0.002 nanometers to about 500 nanometers.

[0071] The present invention also provides a 3D light field sensor, comprising:

[0072] a) a 3D light field detector as disclosed herein; and

[0073] b) A color charge coupled device (CCD) electromagnetically coupled to a 3D light field detector for converting the color output into an electrical signal.

[0074] In some embodiments, the 3D light field detector is coated on a color CCD.

[0075] The color CCD may be a Sony ICX274AL sensor with a chip size of 10 mm x 14 mm (horizontal x vertical) providing 24-bit RGB true color. Alternatively, a 30-bit color display with a 10-bit color depth may be used.

[0076] The CCD may have a photosensitive area of ​​about 10 mm x about 20 mm or about 10 mm x about 14 mm. The CCD may have a pixel size of about 1 x 1 micron square to about 5 x 5 microns square, or about 2.5 x 2.5 microns square.

[0077] In some embodiments, the 3D light field sensor further comprises a lens for light collection.

[0078] In some embodiments, the 3D light field sensor further includes a computer system or controller configured to convert the electrical signal into spatial coordinates in a three-dimensional Cartesian coordinate system. As will be understood, the controller will generally be embodied by electronic components, particularly electronic components programmed to convert the electrical signal into spatial coordinates based on the formulas mentioned herein.

[0079] In some embodiments, the sensor is characterized by having an accuracy of approximately 0.5 mm at a distance of approximately 0.5 meters.

[0080] In some embodiments, the sensor is characterized by a spatial sampling density of about 300 points per square millimeter to about 600 points per square millimeter, or about 400 points per square millimeter.

[0081] The present invention also provides a wavefront sensor comprising a 3D light field sensor as disclosed herein. The 3D light field sensor may be about 5 mm to about 100 mm away from the light source.

[0082] The present invention also provides a method for manufacturing a 3D light field sensor, comprising:

[0083] a) forming or positioning at least one position detector on a transparent substrate;

[0084] Wherein, the at least one position detector comprises at least two luminescent nanocrystal pixels having different emission wavelengths relative to each other.

[0085] In some embodiments, the step of forming or positioning at least one position detector includes photolithographically patterning at least two light-emitting nanocrystal pixels in a silicon template and curing a polymer over the at least two light-emitting nanocrystal pixels to form a transparent substrate.

[0086] In certain embodiments, each of at least two luminescent nanocrystal pixels comprises a plurality of nanocrystals dispersed in a polymer matrix. In certain embodiments, a plurality of nanocrystals are uniformly dispersed in a polymer matrix. In certain embodiments, at least two luminescent nanocrystal pixels are independently characterized in that their nanocrystal density is about 0.001 mol / ml to about 0.01 mol / ml. In other embodiments, the density of nanocrystals is about 0.002 mol / ml to about 0.01 mol / ml, about 0.003 mol / ml to about 0.01 mol / ml, about 0.004 mol / ml to about 0.009 mol / ml, about 0.004 mol / ml to about 0.008 mol / ml, about 0.004 mol / ml to about 0.007 mol / ml, or about 0.004 mol / ml to about 0.006 mol / ml.

[0087] In some embodiments, the plurality of nanocrystals are dispersed in a transparent polymer matrix. The polymer may be a silicon-based polymer.

[0088] In other embodiments, the method includes:

[0089] a) forming or positioning at least three position detectors on a transparent substrate such that the at least three position detectors are configured to cooperate to convert vector quantities of electromagnetic radiation into CIE XYZ tristimulus values;

[0090] Wherein, at least one position detector comprises at least two luminescent nanocrystal pixels having different emission wavelengths relative to each other.

[0091] In other embodiments, the method includes:

[0092] a) arranging position detectors on a transparent substrate such that each position detector is oriented perpendicularly to an adjacent position detector;

[0093] Therein, each position detector includes at least two luminescent nanocrystal pixels having different emission wavelengths relative to each other.

[0094] In some embodiments, the step of arranging the position detector includes photolithographically patterning at least two light-emitting nanocrystal pixels in a silicon template and curing a polymer over the at least two light-emitting nanocrystal pixels to form a transparent substrate.

[0095] In some embodiments, the step of arranging the position detector further comprises photolithographically patterning a third luminescent nanocrystal pixel in another silicon template and adhering it to the transparent substrate having the at least two luminescent nanocrystal pixel patterns.

[0096] The present invention also provides a method of manufacturing a 3D light field sensor, comprising electromagnetically coupling a color charge coupled device (CCD) to a 3D light field detector for converting a color output into an electrical signal.

[0097] Each azimuth detector includes a polychromatic emitting material that converts EM rays incident from a specific direction into a unique color output. This allows the measurement of light fields without the need for complex microlens arrays and photonic crystal processing. This is applicable to a wide variety of color-tunable luminescent materials, and has no wavelength and polarization dependence.

[0098] When two azimuth detectors are arranged perpendicular to each other, they can achieve 3D light field sensing. In an arrangement with three azimuth detectors, the three azimuth angles α are encoded in the color outputs of the three azimuth detectors. 1 , α 2 and α 3 The correlation of the position detectors enables the absolute position of the light source to be determined. Compared to conventional angle detectors, the azimuth detector array can be easily modified in a specific orientation to enable more advanced applications, such as source localization, which is not possible with conventional angle detectors.

[0099] In some embodiments, an array of 3D light field imaging detectors is designed and manufactured, in which adjacent azimuth detectors are aligned perpendicular to each other. The 3D light field imaging array can be used for 3D imaging of objects and wavefronts. The two azimuth detectors are perpendicular to each other, allowing each detector pixel to be multiplexed, thereby increasing the imaging resolution. Importantly, the detector array is manufactured on a transparent substrate film through a simple demolding process, which can be directly integrated into a color CCD to build a light field image sensor without the need for a complex manufacturing process.

[0100] In particular, a single azimuth detector composed of perovskite nanocrystals can enable light field detection with an angular resolution of 0.0018° in the wavelength range of 0.002-500 nanometers. Further, a thin film made with patterned perovskite nanocrystal arrays is integrated on a color CCD for 3D imaging of objects and wavefronts. Using the current structural design, a vector sensitivity of 0.015° and a wavelength response range of 0.002-500 nanometers can be achieved, which are about 100 times and 200 times better than conventional microlens-based detection methods, respectively.

[0101] The work of the present invention is described in detail below. In the following examples, in order to demonstrate the present invention, the present invention is described with respect to some conditions in order to maintain consistency. However, it will be appreciated by the skilled person that the present invention is not limited thereto.

[0102] As an example, inorganic perovskite nanocrystals (CsPbX 3; X = Cl, Br, I). Three groups of perovskite quantum dots emitting at 445 nm, 523 nm, and 652 nm were selected to construct a single azimuth detector. When light is incident from 0 to 360 degrees relative to the reference direction, the detected color gamut forms a large triangle on the CIE xy chromaticity diagram ( Figure 1 c). The position of the color output on the chromaticity diagram determines the angle of incidence of the light, and larger triangles indicate higher angular resolution. 2+ / Mn 2+ and SrAl 2 O 4 :Eu 2+ / Dy 3+ Compared with the detectors made of phosphors, the color gamut of the azimuth detectors made of perovskite nanocrystals forms a larger triangle in the chromaticity diagram ( Figure 1 d) This creates a higher angular resolution due to the wider color coverage and higher color saturation of the perovskite nanocrystals.

[0103] A single azimuth detector with different color gamuts produces a color map of varying shapes (Figure 2a). Interestingly, nanocrystals with red, green, and blue outputs can detect extremely small angular changes. This property was exploited and a single three-color azimuth detector was built on an RGB sensor chip, which converts incident light from 0 to 360 degrees into different CIEXYZ three-color luminescence values ​​(Figure 2b). The minimum detectable angular change is determined by the contrast of the color response and the signal-to-noise ratio (SNR) of the color sensor. In the measurement, there were 65,536 levels for each primary color, resulting in a detection limit of 0.0018° angular change at a wavelength of 405 nanometers and a power of 8 milliwatts (Figure 2c).

[0104] Next, two azimuth detectors arranged perpendicular to each other were designed and fabricated for omnidirectional light field detection (Figure 2d). In spherical coordinates, the formula and Calculate the azimuth angle of each incident beam separately and elevation angle θ, where α 1 and α 2 is obtained from the emission colors of the two azimuth detectors. The two azimuth detectors produce two types of color maps at different incident angles. The contours of the two color maps in the polar plot allow the specific incident angle to be determined by combining the color values ​​of the two azimuth detectors (Figure 2e). An azimuth detector array was further designed to image a 3D light field, in which adjacent pixels of the perovskite nanocrystals are aligned perpendicular to each other (Figure 2f). For simplicity, the angle detected by the detector parallel to the x-axis is denoted by α i,jdenoted by (i and j refer to the rows and columns of the nanocrystal array), and the angle detected by the detector parallel to the y-axis is denoted by β i,j Each of the two mutually perpendicular azimuth detectors can reconstruct the angle at which the beam is incident at the centers of the two pixels. For example, α 1,1 and β 1,2 can be used to calculate the beam at point s 11 The 3D angle of incidence is 2,1 and α 1,1 can be used to calculate the beam at point s 21 Therefore, the spatial resolution of the imaging of the nanocrystal array is given by s 11 With s 12 Next, the thin film of the perovskite nanocrystal array was integrated into a digital camera equipped with a color CCD (Figure 2g). The photosensitive area of ​​the CCD was 10 mm × 14 mm, and the pixel size was 2.5 × 2.5 square microns. The pixel size of a single orientation detector was 50 × 50 square microns and covered a total of 400 CCD pixels.

[0105] Direct applications of light field sensors based on pixelated perovskite nanocrystal arrays are 3D imaging and light detection and ranging (LiDAR) (Figure 3a). The imaging system is based on triangulation and consists of a multi-line structured light source, two lenses for light collection, and a color CCD coated with a nanocrystal array film. The object distance z is determined by measuring the angle of light reflected by the object to the nanocrystal array, which means that high angular resolution provides high depth resolution. For a given pixel size (50×50 square microns), the theoretical depth resolution and detectable range are improved by about 10 times and about 3 times, respectively, compared to conventional triangulation. To improve data accuracy, these nanocrystal arrays are first calibrated, and then the imaging system is calibrated (Figure 3b). When light is reflected from different angles θ and In the case of incident light, the image captured by the perovskite nanocrystal array serves as a corresponding map of the color response of each azimuth detector and the angle of the incident light. To quantitatively evaluate the imaging performance of the prototype, its depth accuracy was measured as a function of scene depth and radial position within the field of view (Figure 3c). These measurements revealed that the optimal depth accuracy was about 0.5 mm at a distance of 0.5 meters, although the depth accuracy dropped slightly to about 1.5 mm at a distance of 2 meters. The depth accuracy of the detector may be affected by the power and angle of the incident light. To ensure high angular resolution, the light source power of the structured light source is adjusted to be sufficiently large. When the detector is used under natural light or bulb conditions, the depth accuracy also varies depending on the intensity of the background light. The size of the objects imaged by the light field sensor at different distances from the light field sensor (0.7 meters, 1.5 meters, and 3 meters) is consistent with the actual size of the object (Figure 3d-Figure 3f). Image reconstruction can also be performed for objects with fine structures, such as keyboards and combs (Figure 3f). Insufficient returned light or random noise may cause pixels to not be detected. Furthermore, using a pixelated color conversion strategy, 3D images of several objects of different colors, sizes, and materials were obtained at gradually increasing depths.

[0106] Another important application of pixelated color conversion is phase contrast imaging over an ultra-wide wavelength range from X-rays to visible light (0.002-500 nm). In phase contrast imaging using a conventional Shack–Hartmann wavefront sensor, a microlens array records the angle of incidence on a series of grid points that determine the wavefront (Figure 4a). Light field sensors based on nanocrystal arrays can directly measure the specific angle of visible light or X-rays to reconstruct the wavefront without the need for a microlens array. The divergent wavefront of a hard X-ray beam was first characterized by placing the light field sensor at 14 mm and 20 mm from the X-ray source (Figures 4b and 4c). The measured wavefront curvature is in good agreement with analytical calculations, and the maximum angle measured by the light field sensor is 40.6°. The mapping of the visible light wavefront in the image plane is also demonstrated when the lens is illuminated by visible light at two different field of view angles (Figures 4d and 4e). Furthermore, phase contrast imaging was performed using visible light on polydimethylsiloxane (PDMS) patterns and X-rays on commercial polymethyl methacrylate (PMMA) rods (Figures 4f and 4g). Compared with absorption contrast imaging, phase contrast imaging can see the surface structure in more detail.

[0107] Compared to microlens array fabrication, nanocrystal light field sensors can be fabricated with high robustness and high uniformity over large areas. In experiments, spatial sampling density was 400 points per square millimeter, angular resolution was 0.015°, and dynamic angular range was greater than 90 degrees. In comparison, commercial Shack-Hartmann sensors (Thorlabs WFS30-5C) typically have a lower sampling density of 44 points per square millimeter and a smaller dynamic angular range of less than 2°. Nanocrystal light field sensors are also suitable for a wider spectral range.

[0108] In summary, a pixelated color conversion strategy based on perovskite nanocrystal arrays is presented for 3D light field detection, absolute spatial localization, 3D imaging, and visible / X-ray phase contrast imaging. With its current design, a vector sensitivity of 0.0018° and a wavelength response range of 0.002-700 nm have been achieved, which are nearly 100 times and 200 times better than conventional microlens-based detection methods, respectively. The angular accuracy can be further improved by integrating high-end color detectors. For example, a 30-bit color display with 10-bit color depth can produce 1.07 billion possible combinations. With advanced lithography methods and state-of-the-art processing technology, the density of azimuth detectors should be achievable to exceed ten thousand pixels per square millimeter, which can greatly improve the spatial resolution of imaging. In addition, the pixelated color coding strategy for light field detection and imaging can be easily extended to optical materials other than the perovskite nanocrystals presented in this paper. Tin-based perovskite nanocrystals, near-infrared-responsive upconversion nanoparticles, or black phosphorus with tunable band gaps can extend angular detection to the near-infrared and even micrometer wavelength ranges. Furthermore, in contrast to Shack-Hartmann sensors, light field sensors based on nanocrystal arrays can be directly integrated into on-chip optical systems to measure wavefronts or phase. Since azimuth detectors can only distinguish the average vector direction of incident light, and cannot distinguish light from multiple directions like light field cameras, light field sensors measure the average vector direction of light at each pixel. As with light field cameras, nanocrystal light field sensors must strike a balance between angular resolution and spatial resolution. Scanning light field imaging systems can be coupled to nanocrystal arrays to further improve spatial resolution. Nevertheless, the ability to map high-energy X-ray wavefronts provides a powerful solution for optical testing and beam characterization, while opening up new applications from phase contrast imaging to gravitational wave detection.

[0109] method

[0110] Chemicals

[0111] Cesium carbonate (Cs 2 CO 3 , 99.9%), lead(II) chloride (PbCl 2, 99.99%), lead (II) bromide (PbBr 2 , 99.99%), lead (II) iodide (PbI 2 , 99.99%), oleylamine (technical grade 70%), oleic acid (technical grade 90%), 1-octadecene (technical grade 90%), and cyclohexane (chromatographic grade 99.9%) were purchased from Sigma-Aldrich. The Sylgard 184 silicone elastomer kit used for the preparation of polydimethylsiloxane (PDMS) substrates was purchased from Dow Corning. ZnS / CdSe phosphors were purchased from Xiucai Chemical Co., Ltd. (Foshan, China).

[0112] Synthesis and characterization

[0113] CsPbX was synthesized according to the method described in the literature. 3 (X = Cl, Br or I) perovskite nanocrystals. First, cesium oleate was synthesized as a cesium precursor, and then CsPbX was synthesized using a modified hot injection method. 3 Perovskite nanocrystals.

[0114] Transmission electron microscopy (TEM) was performed on the synthesized perovskite nanocrystals using a FEI Tecnai G20 transmission electron microscope with a 200 kV accelerating voltage. Under visible light or X-ray excitation, perovskite quantum dots (QDs) emit narrow and color-tunable visible emission. Photoluminescence and radioluminescence spectra were obtained using an Edinburgh FS5 fluorescence spectrophotometer (Edinburgh Instruments Ltd., UK) equipped with a micro X-ray source (AMPEK, Inc.). An advantageous attribute of perovskites as detectors is their linear response to X-ray dose rate or excitation light power, covering a range of up to several orders of magnitude. The lowest detectable dose rate for X-ray detection is 10.8-13nGy s -1 , and the lowest detectable power for optical detection is 1pW / mm -2 The perovskite QDs also exhibited a very fast response to pulsed excitation (decay time, τ = 10.4 ns). These nanocrystals showed high photostability under continuous or repeated cycles of X-ray irradiation and photoexcitation.

[0115] Fabrication and Integration of 3D Light Field Sensor Arrays

[0116] 3D light field sensors based on pixelated perovskite nanocrystal arrays are fabricated via a simple molding process ( Figure 5). First, the pre-patterned silicon template was washed thoroughly with heptane. A colloidal QD solution was prepared by redispersing the synthesized red, green, and blue QDs in a cyclohexane solution and stirring vigorously. A 10:1:1 (v:v:v) mixture of SYLGARD Silicone Elastomer 184, curing agent, and QDs was prepared in cyclohexane (5 mol%). Then, the prepared red-emitting QD-PDMS ink and blue-emitting QD-PDSM ink were injected into the corresponding rectangular holes on the silicon template and cured at 90°C for 30 min. The top of the injected QD ink must be flush with the top of the silicon template. Next, a 0.5 mm thick PDMS was spin-coated onto the surface of the silicon template as an adhesive film. After curing at 90°C for 30 min, a PDMS film with red and blue pixel patterning was molded from the silicon template. Similarly, the green-emitting quantum dot ink was injected into another silicon template and cured at 90°C for 30 min. Then, a layer of transparent PDMS was coated on the previously treated PDMS film printed with red and blue pixels, which was then covered on the template injected with green emission ink on the mask aligner holder. Finally, after curing at 90°C for 30 minutes, the film with red, green and blue pixel arrays was obtained by a demolding process. A 3D light field sensor was formed by integrating the treated pixelated perovskite nanocrystal array film into a color CCD, in which each angle-sensitive pixel covered multiple CCD pixels. The color CCD is a Sony ICX274AL sensor with a chip size of 10 mm × 14 mm (horizontal × vertical) and provides 24-bit RGB true color.

[0117] In current 3D printing molds, the size can be adjusted from tens of microns to several millimeters. Large-scale manufacturing is possible through repeated demolding. This method eliminates the need for complex semiconductor processes and special gases, thereby greatly reducing processing costs. Manufacturing errors typically include random defects and alignment errors. Since the demolding process used in this work has high processing accuracy and edge defects can be controlled within 0.1%, the random defect error of the entire azimuth detector pixel is almost negligible. Since the upper and lower layers need to be aligned, layer alignment errors will occur during processing. In the case where the image distance is much larger than the thickness of the monochrome pixel, the alignment deviation will not affect the angle measurement.

[0118] Calibration of 3D Light Field Sensors

[0119] The 3D light field sensor based on perovskite nanocrystal arrays was calibrated under a collimated LED light source. A motorized rotation stage (Daheng Optoelectronics, GCD-011060M), a pitch stage, and a linear stage were connected to adjust the θ and The image sensor is attached to the pitch platform. The pitch platform moves in the θ direction, while the rotation stage moves in the The linear stage is used to compensate for off-axis motion when the image sensor is rotated in the θ direction. Selected raw color images captured during the calibration process are shown to illustrate the working principle of the 3D light field sensor ( Figure 6 ). Each panel depicts a cropped region of the original color image taken at different incident angles. Here, the angular dependence of the color output of each pixel can be observed. The yellow squares represent vertical angle-sensitive cells, while the red squares represent horizontal angle-sensitive cells. When θ increases from -40° to 40°, and As θ increases from -40° to 40°, the blue color of the pixels in the yellow square gradually weakens. As θ and Once calibration is completed for the entire range of the image, the captured raw image is used as a lookup table for each angle-sensing pixel to determine the incident angle of light.

[0120] 3D Imaging Program

[0121] The homemade optical setup for 3D imaging consists of a light source and a grating to generate multi-line structured light on the 3D scene to be imaged ( Figure 7 ). The reflected / scattered light from the object is collected by a homemade objective lens consisting of two lenses optimized for focal lengths of 100 mm and 25 mm, respectively, allowing the maximum angular variation of different object distances to be identified by the developed high-resolution 3D light field sensor. In a typical experiment, the parameters of the multi-line structured light and the camera, as well as the relative distance between them, are first calibrated. Next, the color output of each detector is mapped to an angle array based on the calibration results, and then the spatial coordinates x, y, and z of the object point corresponding to each angle detection unit can be calculated based on the geometric model of the 3D imaging system, as described below.

[0122] Spherical X-ray wavefront measurement

[0123] 3D light field sensors are used to measure the wavefront of spherical hard X-rays (14keV) Figure 8 ). The X-ray source produces a divergent light beam with a divergence angle of about 90 degrees, and its wavefront is measured at different positions. The farther the 3D light field sensor is from the X-ray source, the smaller the radius of curvature of the measured spherical wavefront becomes. Furthermore, based on the reconstructed wavefront and slope mapping, the tilt angle between the X-ray source and the sensor can be identified. As a proof of principle, the color data mapping at z = 5 mm was used as calibration data for reconstructing the wavefront at other distances z, which resulted in a decrease in the accuracy of the slope measurement as z increased. In practical applications, a sufficient number of sampling angles must be obtained to ensure angular resolution.

[0124] Phase contrast imaging procedure

[0125] In phase contrast imaging with collimated UV / visible light, the object is a patterned PDMS substrate with a strip thickness of 0.6 mm. The light field imaging sensor is placed directly behind the object to capture the altered wavefront image. In order to obtain a nearly collimated beam for X-ray phase contrast imaging, a copper rod collimator is located behind the radiation source. Two commercial PMMA rods with diameters of 1 mm and 2 mm are placed behind the radiation source, and the light field imaging sensor detects the altered wavefront. Specifically, the light field imaging sensor acquires pixelated beam angles, which characterize the phase gradient distribution. After median filtering and integration of the phase gradient, phase mapping can be achieved.

[0126] Positioning principle and error analysis

[0127] The photoluminescent part of the position detector consists of three groups of CsPbX 3 Nanocrystals emit red, green and blue light. Since the absorption of light or radiation by each part changes with the incident direction of light, there is a mapping between the luminescent color and the azimuth angle of the excitation light. Each azimuth detector can determine the angle α of the incident light beam relative to the reference plane, so three such azimuth detectors can be arranged to locate the spatial position of the excitation source. In a three-dimensional Cartesian coordinate system, detector A and detector B are perpendicular to the XOY plane at coordinates (b, 0, 0) and coordinates (0, 0, 0), while cylinder C is arranged along the Y axis parallel to the XOY plane. Assuming that the X-axis is the reference direction, the projection of the light source or radiation source S on the XOY plane is S′, and the angle between the line (connecting S′ and detector A) and the reference direction is θ 1 , and the angle between the line (connecting S′ and detector B) and the reference direction is θ 2 The angle between the line (connecting S and detector C) and the XOY plane is θ 3 θ 1 ,θ 2 and θ 3 They are determined by the emission colors of the position detectors A, B, and C. Therefore, the spatial position (x, y, z) of the source S can be solved by the following formula:

[0128]

[0129] The positioning errors dx, dy and dz of the source S depend on the angular detection error dθ of each azimuth detector, the distance b and the position coordinates x, y and z of the source. dx, dy and dz as a function of dθ are:

[0130]

[0131] as well as

[0132] dz=dx tanθ 3 +x sec2 θ 3 dθ

[0133] Theoretical analysis shows that dx, dy, and dz are all positively correlated with dθ, dx is positively correlated with b, and dy and dz are negatively correlated with b. The positioning error is closely related to the position of S.

[0134] Principle of 3D light field detection

[0135] Two azimuth detectors arranged perpendicular to each other can perform 3D omnidirectional light field detection. In spherical coordinates, for The incident light beam, detector 1 detects the angle α between the projection of the light beam on the YOZ plane and the Z axis 1 , while detector 2 detects the angle α between the projection of the light beam on the XOZ plane and the Z axis 2 α 1 , α 2 and θ, The relationship between them is as follows:

[0136]

[0137] where α 1 and α 2 Encode the color outputs of detector 1 and detector 2 respectively. In the specific experiment, α 1 and α 2 are obtained from the CIE tristimulus values ​​of the color outputs of detector 1 and detector 2, respectively. Then, the azimuth of the light beam is obtained according to the following expression derived from the equation and the elevation angle θ:

[0138]

[0139] We further designed a 3D light field imaging array using perovskite nanocrystals, in which adjacent pixels are perpendicular to each other. For simplicity, the angle detected by the detector parallel to the x-axis is denoted by α i,j , where i and j refer to the rows and columns of the nanocrystal array, and the angle detected by the detector parallel to the y-axis is denoted by β i,j Each of the two azimuth detectors, which are perpendicular to each other, can reconstruct the angle at which the beam is incident at the center of the two pixels. For example, α 1,1 and β 1,2 can be used to calculate the beam at point s 11 The 3D angle of incidence is 2,1 and α 1,1 can be used to calculate the beam at point s 21 The 3D angle of incidence.

[0140] Geometric model of 3D imaging system

[0141] The 3D imaging scheme used is a triangulation method based on multi-line structured light illumination. For simplicity, the case of single-line structured light illumination is first analyzed ( Fig. 9 ). In order to increase the change of the incident angle on the detector with distance and reduce the lateral movement of the light spot on the detector, an objective consisting of two lenses is designed. 1 and L 2 are the center points of lens 1 and lens 2 respectively. The light source at point O emits a single line structured light perpendicular to the XOZ plane, and point O and L 1 The distance between them is D. For each object point P (x, y, z) irradiated by the single-line structured light, its image through lens 1 in the X0Y0Z0O0 coordinate system of lens 2 is located at point P0 on the X0O0Y0 plane. The X0O0Z0 plane is coplanar with the XOZ plane. The angle between the ray OP and the XOZ plane is The angle between the projection OP' of the ray OP on the XOZ plane and the OX axis is α. The angle between the optical axis O0Z0 of lens 1 and OL1 is β z The angle between the projection P′L1 of the ray PL1 on the X0O0Z0 plane and the optical axis O0Z0 is β 0 , and the angle between the projection PzL1 of the ray PL1 on the Y0O0Z0 plane and the optical axis O0Z0 is θ 0 . Fig. 9 b and Fig. 9 c shows the projection of the coordinate system of lens 1 onto the XOZ plane and the Y0O0Z0 plane. The light L1P0 is refracted by lens 2 onto the detector plane X1O1Y1. Fig. 9 d and Fig. 9 e shows the projection of the camera's coordinate system on the XOZ plane and the Y0O0Z0 plane. The angle between the projection of the ray P0P1 on the X1O1Z1 plane and the optical axis O0Z0 is β 1 , and the angle between the projection of ray P0P1 on the Y1O1Z1 plane and the optical axis O1Z0 is θ 1 The distance between lens 1 and lens 2 is d, and the distance between lens 2 and the detector plane is l. n and m represent the number of pixels on the detector in the X and Y directions, respectively.

[0142] according to Fig. 9 The geometric relationship in can be used to solve the position coordinates x, y, z of the object point P:

[0143]

[0144] x=z cotα

[0145]

[0146] tanβ0 =(ltanβ 1 -ns) / d

[0147] tanθ 0 =(ltanθ 1 -ms 1 ) / d

[0148] where s and s 1 denote the size of a single pixel of the detector in the X and Y directions, respectively.

[0149] In specific experiments, α and β need to be calibrated in advance. z , D, d and l. Obtain β from the color output of angle detection 1 and θ 1 , and then use the formula to solve the coordinates x, y, and z of object P.

[0150] Parameter selection of 3D imaging system.

[0151] exist Fig.10 In the 2D scheme of the imaging system designed in , at a certain distance z, the lateral position x of the reflected or scattered light PL1 and the angle βt with the X-axis are:

[0152] x=z cot(α)

[0153] β t =arctam[z / (Dx)]

[0154] according to Fig.10 The geometric relationship in and Gauss's formula in geometric optics, the object distance l of lens 1 1 and image distance l 1 'for:

[0155]

[0156] where f 1 is the focal length of lens 1, β z It is the angle between the optical axis of lens 1 and the coordinate axis OX.

[0157] Object distance l of lens 2 2 and image distance l 2 'for:

[0158] l 2 = l 1 ′-d, and

[0159] where f 2 is the focal length of lens 2.

[0160] Lens 1 (β 1 )、Lens 2(β2 ) and the vertical magnification of the combined system (β) is:

[0161] and

[0162] Therefore, the image heights on the primary imaging plane and the detector imaging plane are:

[0163] y 1 ′=y 1 β 1 , and y 2 ′=y 1 β

[0164] where y 1 =-l 1 tan(β t -β z ).

[0165] The angle between the light beam incident on the main imaging plane and the optical axis is:

[0166] β 0 =β t -β z

[0167] The angle between the light beam incident on the imaging plane of the detector and the optical axis is:

[0168]

[0169] The goal of parameter optimization is to make y 2 ′ changes the least with distance z, and β 0 ′ changes the most with z. Therefore, we analyze δy 2 ′ / δz and δβ 0 ′ / δz and system parameters D, α, β z , d, f 1 and f 2 Considering the resolution and detectable distance range, the system parameters are set to D = 50 mm, α = 90°, β z =78°, f 1 =75 mm, f 2 =25 mm, and d =145 mm. The optimal imaging parameters are listed in Table 1.

[0170] Table 1. Optimal parameters for imaging a 500 mm distance range

[0171]

[0172] When the distance z changes by 0.1 mm, the angle β of the light incident on the detector 0' changes by about 0.0038°, and the spot moves about 1 micron on the detector, which is indistinguishable for a conventional CCD with a pixel size of 3-10 microns. By attaching a light field imaging film to the CCD, a distance change of 0.1 mm can be distinguished by angle detection. Under optimized system parameters, a distance change of 200 mm causes the spot on the detector to move 1.4 mm. It should be noted that the choice of imaging parameters depends largely on the distance z, so the system parameters must be determined according to the distance range of the application.

[0173] Calibration of 3D imaging systems

[0174] Calibration of emission angle of multi-line structured light

[0175] The system uses a grating after the light source to generate multi-line structured light and scans the surface of the object in normal incidence mode. The angle between the two edge light planes of the structured light is α, and the angle between each structured light plane and the XOY plane is α i , and the angle between the structured light planes is w( Fig.11 ). Since the structured light is incident perpendicular to the target, α can be obtained by the following formula i :

[0176] αi=90°±nw

[0177] Where n represents the number of line structured light planes.

[0178] In actual calibration, the structured light is incident vertically on the white plate, OO' is the optical axis of the light source, and points A, B, C, and D are the four corner points of the edge light strip on the surface. Points A', B', C', and D' are the four corner points of the edge light strip after the plate moves a certain distance. The coordinates of A, B, C, D, A', B', C', and D' are measured, and the plane equations of plane AA'D'D and plane BCC'B' can be established in the Cartesian coordinate system:

[0179] a 1 x+b 1 y+c 1 z+d 1 =0

[0180] a 2 x+b 2 y+c 2 z+d 2 =0

[0181] Then the angle α between the two edge light planes of the structured light is:

[0182]

[0183] Calibration of homemade camera parameters

[0184] The world coordinate system of CCD (x w ,y w , z w ) and the pixel coordinate system (u, v) is:

[0185]

[0186] Where s is the scale factor, K is the camera's intrinsic parameter matrix, R is the camera's rotation matrix in the world coordinate system, and T is the translation matrix. Zhang's calibration method is used to determine the camera's intrinsic parameters, extrinsic parameters, and distortion parameters. First, a piece of paper with a black and white grid is printed, and then several images of the paper are taken from different angles using the camera to be calibrated. In addition, the feature points in the collected images are identified and processed using Matlab's camera calibration library toolbox_calib to obtain the camera's intrinsic parameters, extrinsic parameters, and distortion parameters.

[0187] Wavefront detection principle

[0188] Wavefront detection of extreme ultraviolet (EUV) light or X-rays typically uses the Hartmann (e.g., Shack-Hartmann) wavefront sensing technique, in which a beam passes through an array of holes (e.g., a microlens array) and is projected onto a CCD camera, which detects the beam sampled from each hole (e.g., microlens). The position of the centroid of a single point is then measured and compared to a reference position. This enables the local slope of the wavefront to be measured at a large number of points by the following formula:

[0189]

[0190] In light field sensor based wavefront measurement, the local slope of the wavefront is directly obtained by an angle detector without the need for an aperture or microlens array.

[0191] The local slope of the wavefront can be written as:

[0192]

[0193] where W(x, y) represents the optical path difference, and is the spatial phase. Integrating the measured derivative function enables reconstruction of the incident beam wavefront.

[0194] It will be appreciated that numerous additional modifications and permutations of the various aspects of the described embodiments are possible. Accordingly, the described aspects are intended to embrace all such changes, modifications and variations that fall within the spirit and scope of the appended claims.

[0195] Throughout this specification and the claims that follow, unless the context requires otherwise, the word "comprise" and variations such as "comprising" and "containing" will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

[0196] Throughout the specification and the claims that follow, unless the context requires otherwise, the phrase "consisting essentially of" and variations thereof (such as "consisting essentially of") will be understood to indicate that the recited element(s) are essential, i.e., necessary elements of the invention. The phrase allows for the presence of other unrecited elements that do not materially affect the characteristics of the invention, but excludes other unspecified elements that affect the basic and novel characteristics of the defined method.

[0197] Reference in this specification to any previous publication (or information derived therefrom) or any known matter is not and should not be taken as an acknowledgement or approval, or any form of implication that the previous publication (or information derived therefrom) or known matter forms part of the common general knowledge in the field to which this specification relates.

Claims

1. A light field detector for converting a vector of electromagnetic radiation into a color output, comprising at least one position detector on a transparent substrate, and the at least one position detector comprises at least two luminescent nanocrystal pixels, the at least two luminescent nanocrystal pixels having different emission wavelengths relative to each other.

2. The light field detector of claim 1, comprising at least two of said azimuth detectors oriented perpendicularly to each other.

3. A light field detector according to claim 1 or claim 2, comprising at least three azimuth detectors, the at least three azimuth detectors being configured to cooperate to convert the vector of electromagnetic radiation into CIE XYZ tristimulus values.

4. The light field detector according to any one of claims 1 to 3 comprises at least three azimuth detectors, wherein the at least three azimuth detectors are oriented so that a first azimuth detector and a second azimuth detector are parallel to each other, and a third azimuth detector is substantially perpendicular to the first azimuth detector and the second azimuth detector.

5. The light field detector of any one of claims 1 to 4, wherein the at least two luminescent nanocrystal pixels are parallel to each other.

6. A light field detector according to any one of claims 1 to 5, wherein the emission wavelength corresponds to red, green or blue.

7. The light field detector of any one of claims 1 to 6, wherein the at least two luminescent nanocrystal pixels are three luminescent nanocrystal pixels.

8. The light field detector of claim 7, wherein three luminescent nanocrystal pixels are stacked such that they form a semi-cylindrical configuration or a rectangular pyramidal configuration.

9. A light field detector according to any one of claims 1 to 8, wherein the luminescent nanocrystal pixels comprise perovskite nanocrystals, ZnS:Cu 2+ / Mn 2+ 、SrAl2O4:Eu 2+ / Dy 3+ Phosphors, upconversion nanoparticles, black phosphorus, or a combination thereof.

10. The light field detector of claim 9, wherein the perovskite nanocrystals are CsPbX3, wherein X is selected from Cl, Br and / or I.

11. A light field detector according to claim 9 or claim 10, wherein the perovskite nanocrystals are characterized by an emission wavelength of about 445 nanometers, about 523 nanometers, or about 652 nanometers.

12. The light field detector of any one of claims 1 to 11, wherein each position detector is characterized by a size of about 1 x 1 square micrometer to about 200 x 200 square micrometers.

13. The light field detector according to any one of claims 1 to 12, wherein the 3D light field detector is characterized in that its angular change detection limit is less than 0.015°.

14. The light field detector of any one of claims 1 to 13, wherein the light field detector is characterized by a density of position detectors of about 80 position detectors per square millimeter to about 200 position detectors per square millimeter.

15. A light field detector according to any one of claims 1 to 14, wherein the transparent substrate is a polymer substrate, or preferably PDMS.

16. The light field detector of any one of claims 1 to 15, wherein the electromagnetic radiation has a wavelength of about 0.002 nanometers to about 500 nanometers.

17. A light field sensor comprising: a) A light field detector according to any one of claims 1 to 16; as well as b) a color charge coupled device (CCD) electromagnetically coupled to the light field detector for converting the color output into an electrical signal.

18. The light field sensor of claim 17, further comprising a computer system configured to convert the electrical signal into spatial coordinates in a three-dimensional Cartesian coordinate system.

19. A light field sensor according to claim 17 or claim 18, wherein the sensor is characterised by having an accuracy of approximately 0.5 mm at a distance of approximately 0.5 m.

20. The light field sensor of any one of claims 17 to 19, wherein the sensor is characterized by a spatial sampling density of about 300 points per square millimeter to about 600 points per square millimeter.

21. A method of manufacturing a light field detector, comprising: a) forming or positioning at least one position detector on a transparent substrate, Wherein, each orientation detector includes at least two luminescent nanocrystal pixels, and the at least two luminescent nanocrystal pixels have different emission wavelengths relative to each other.

22. A method according to claim 21, wherein the step of forming or positioning at least one orientation detector includes photolithographically patterning the at least two luminescent nanocrystal pixels in a silicon template and curing a polymer over the at least two luminescent nanocrystal pixels to form the transparent substrate.

23. The method of claim 21, wherein the step of forming or positioning at least one orientation detector further comprises photolithographically patterning a third luminescent nanocrystal pixel in another silicon template and adhering it to the transparent substrate having the at least two luminescent nanocrystal pixel patterns.

24. The method of any one of claims 21 to 23, wherein each of the at least two luminescent nanocrystal pixels comprises nanocrystals dispersed in a polymer matrix.

25. The method of any one of claims 21 to 24, wherein the at least two luminescent nanocrystal pixels are each independently characterized by a nanocrystal density of about 0.001 mol / ml to about 0.01 mol / ml.

26. The method according to any one of claims 21 to 25, wherein a) forming or positioning at least one position detector on the transparent substrate comprises arranging a plurality of position detectors on the transparent substrate such that each position detector is oriented perpendicular to an adjacent position detector, in, Each position detector includes at least two light-emitting nanocrystal pixels having different emission wavelengths relative to each other.

Images