CN216901121U - Superlens-based detector array - Google Patents

Abstract

The present disclosure provides a superlens based detector array to improve the detection of oblique light. The superlens-based detector array is composed of an array of detector units; the detector unit comprises a reflecting film, a super lens unit and a detection element which are sequentially arranged along the vertical direction; the reflective film is provided with an aperture for limiting incident radiation; the super lens unit comprises a substrate and structural units arrayed on the surface of the substrate, wherein the structural units are composed of periodically arranged nano structures; the superlens unit is configured to: the angularly incident radiation is deflected and focused onto the detection element. The scheme increases the maximum chief ray angle which can be tolerated in the traditional lens scheme, does not need to carry out translation of the lens, and has the advantages of simple design and processing and additionally reduced volume.

Description

Superlens-based detector array

Technical Field

The application relates to the field of detectors, in particular to a detector array based on a super lens.

Background

When the micro-lens array is used for focal plane imaging, the micro-lens array is arranged above the detector array, so that the filling factor of pixels is improved, and the luminous flux passing through the absorption area is improved. Wherein, the light passing through the center or optical axis of the lens is vertically incident to the micro lens array so as to be focused on the detector; however, when light is incident at a certain chief ray angle, the light cannot be focused on the detector or the middle absorption area after passing through the microlens array, so that the illumination intensity is reduced, and the edge pixel sensitivity is reduced.

In order to solve the above problems in the prior art, a solution often adopted is to translate the microlens, refract the light, and refocus the light lost before the lens is not translated to the light absorption region. This introduces the corresponding translation calculation correlation algorithm and irregular microlens array processing, making the overall work complicated.

SUMMERY OF THE UTILITY MODEL

To overcome the above-mentioned drawbacks of the prior art, the present application provides a superlens-based detector array to improve the detection capability of oblique light.

The superlens-based detector array is composed of an array of detector units; the detector unit comprises a reflecting film, a super lens unit and a detection element which are sequentially arranged along the vertical direction;

the reflective film is provided with an aperture for limiting incident radiation;

wherein the superlens unit includes a substrate, an

The structural units are arrayed on the surface of the substrate and consist of periodically arranged nano structures;

wherein the superlens cell is configured to: the angularly incident radiation is deflected and focused onto the detection element.

Preferably, a support layer or support structure is disposed between the reflective film and the superlens unit. The support layer is transparent to incident radiation in the operating band.

Preferably, the support layer is quartz glass, and the reflective film is formed on the surface of the quartz glass in a deposition manner.

Preferably, an adhesive layer is arranged between the superlens unit and the detection element, and the adhesive layer can transmit radiation of an operating waveband and is filled around the detection element.

Preferably, the probe element and the superlens unit are formed in a wafer level package.

Preferably, the device further comprises a base for supporting the detecting element.

Preferably, the structural unit is a regular hexagon, and each vertex and the central position of the regular hexagon are provided with at least one nano structure.

Preferably, the structural unit is a square, and at least one nanostructure is arranged at each vertex and the central position of the square.

Preferably, the nanostructure is a polarization-dependent structure or a polarization-independent structure;

wherein the polarization-dependent structure comprises a fin-shaped cylinder or an elliptic cylinder and the polarization-independent structure comprises a cylinder or a square cylinder.

Preferably, in the detector array, the substrate of each superlens unit is integrally formed.

Preferably, a filling material is arranged between the nano structures.

Based on the technical scheme, the position of setting the convergent lens in the existing design is changed into setting the aperture diaphragm, and the super lens is arranged below the convergent lens, namely, the light is deflected and is incident on the detector at the angle of zero main light. The lens has the advantages that the maximum chief ray angle which can be tolerated in the traditional lens scheme is increased, the lens does not need to be translated, the design and the processing are simple, and in addition, the volume is additionally reduced.

On the other hand, the hole arranged on the metal reflecting film is used as an aperture diaphragm, so that the whole light path has the characteristics of a telecentric optical system, and part of light rays are blocked at the diaphragm, so that the focal position of the main light rays of the object space in the light path tends to infinity, and the detection targets with different distances, especially the detection targets with longer distances, have higher adaptability.

Drawings

FIG. 1 is a schematic diagram of a detector array (unit) configuration according to the present disclosure;

FIG. 2 is an optical diagram of a detector unit of the present disclosure and its comparison with the prior art;

FIG. 3 illustrates the conditions to be met by the maximum incident chief ray angle in the optical path;

FIG. 4 is a schematic diagram of structural elements in a superlens unit;

FIG. 5 is a schematic diagram of nanostructures in a superlens unit;

the figure is marked with:

1 a metal reflective film; 2 quartz glass; 3 a superlens unit; 4 a binder layer; 5 a detecting element; 6, a base;

31 a nanostructure; 32 a substrate; 33 a filler material.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.

Detailed Description

The present disclosure now will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments are shown. This disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Like reference numerals refer to like parts throughout. Also, in the drawings, the thickness, ratio and size of the components are exaggerated for clarity of illustration.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, "a," "an," "the," and "at least one" do not denote a limitation of quantity, but rather are intended to include both the singular and the plural, unless the context clearly dictates otherwise. For example, "a component" means the same as "at least one component" unless the context clearly dictates otherwise. "at least one of" should not be construed as limited to the quantity "one". "or" means "and/or". The term "and/or" includes any and all combinations of one or more of the associated listed items.

Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms defined in commonly used dictionaries should be interpreted as having the same meaning as is in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

The meaning of "comprising" or "comprises" indicates a property, a quantity, a step, an operation, a component, a part, or a combination thereof, but does not exclude other properties, quantities, steps, operations, components, parts, or combinations thereof.

Embodiments are described herein with reference to cross-sectional views that are idealized embodiments. Thus, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments described herein should not be construed as limited to the particular shapes of regions as illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, regions shown or described as flat may typically have rough and/or nonlinear features. Also, the acute angles shown may be rounded. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region and are not intended to limit the scope of the claims.

As can be seen from the left diagram in fig. 2, incident light rays passing through a conventional lens (one cell in the microlens array) that are oblique to the optical axis are converged on the outer side of the detection element, making it impossible to detect efficiently. In view of this, the present disclosure provides a superlens-based detector array, comprised of an array of detector cells; the detector unit comprises a reflecting film, a super lens unit and a detecting element which are sequentially arranged along the vertical direction. Optionally, a support layer or structure may also be included between the reflective film and the superlens unit. Exemplarily, as shown in fig. 1, from the top (the direction of the incident radiation source) to the bottom (the direction of the detector), there are a metal reflective film 1, a quartz glass 2 (as a support layer), a superlens unit 3, an adhesive layer 4, a detection element 5, and a base 6;

the reflective film is provided with an aperture 11 for limiting incident radiation; the supporting layer can be permeable to incident radiation in the operating band;

wherein the superlens unit 3 includes a substrate 32, an

The structural units are arrayed on the surface of the substrate and consist of periodically arranged nano structures 31;

wherein the superlens unit is configured based on the phase distribution of the nanostructures 31 to: the angularly incident radiation is deflected and focused to the detecting element 5.

Supplementary explanations for the examples are:

the metal reflecting film plays a role in reflecting external light, and on the premise of adopting quartz glass as a supporting layer, the processing technology is that the metal reflecting film is deposited on the surface of the quartz glass, and a hole 11 is carved in the center to form a diaphragm; the supporting layer can be made of quartz glass and plays a supporting role; the superlens unit 3 and the detecting member 5 are bonded using glue; finally becoming a device or an array device. The optical path diagram of the embodiment is shown in fig. 2, and it can be seen that if a conventional lens is used, the incident light cannot be condensed onto the detecting element 5; the superlens can be used to converge on the detecting element 5, so that the detecting capability is improved.

The hole 11 arranged on the metal reflecting film is used as an aperture diaphragm, so that the whole light path has the characteristics of a telecentric optical system, and part of light rays are blocked at the diaphragm, so that the focal position of the main light rays of an object space in the light path tends to infinity, and the detection targets with different distances, especially the detection targets with longer distances, have higher adaptability.

The supporting layer or the supporting structure is used for determining the distance and the relative position relation between the reflecting film and the super lens unit, and the light transmission cannot be influenced. Optionally, a solid layer of transparent material in fig. 1, such as a glass material; the reflective film and superlens unit may also be formed in a wafer level package, in which case an edge formed support structure may be used to the same effect.

As shown in FIG. 3, when the system parameters are determined, including the focal length of the super lens and the size of the detecting element 5 in a single pixel, the maximum incident chief ray angle theta supported by the system is obtained_max. Therefore, the chief ray angle theta of the optical system in which the detector is located is limited_CRAThe following conditions are to be satisfied:

in the above formula, d is the diameter of the detecting element, and f is the focal length of the super lens unit.

Meanwhile, the system uses the super lens scheme, so that the requirement on the image distance is not required, namely the distance between the super lens and the detection element 5 can be small, and the volume of the whole detector can be reduced.

In an embodiment, the superlens unit is a super surface disposed on a transparent substrate. The super surface is a layer of sub-wavelength artificial nano-structure film, and incident light can be modulated according to super surface structure units on the super surface. The super-surface structure unit comprises a full-medium or plasma nano antenna, and the phase, amplitude, polarization and other characteristics of light can be directly adjusted and controlled. In this example, the nanostructure is an all-dielectric structural unit, and has high transmittance in a target wavelength band, and the selectable materials include: titanium oxide, silicon nitride, fused silica, aluminum oxide, gallium nitride, gallium phosphide, amorphous silicon, crystalline silicon, hydrogenated amorphous silicon, and the like. The nanostructures may be filled with air or other transparent or semitransparent material with other working wavelength bands, and it should be noted that the absolute value of the difference between the refractive index of the material and the refractive index of the nanostructures is greater than or equal to 0.5.

The plurality of superlens units, based on phase modulation of the nanostructures therein, are identically or differently configured.

The structural unit is a regular hexagon, and each vertex and the central position of the regular hexagon are at least provided with one nano structure. Or the structural unit is a square, and at least one nano structure is arranged at each vertex and the center of the square. Ideally, the structural units should be hexagonally-arranged and centrally-arranged nanostructures or quadrate-arranged and centrally-arranged nanostructures, and it should be understood that the actual product may have the loss of nanostructures at the edge of the superlens due to the limitation of the superlens shape, so that the actual product does not satisfy the complete hexagon/quadrate. Specifically, as shown in fig. 4, the structural units are formed by regularly arranging nanostructures, and a plurality of structural units are arranged in an array to form a super-surface structure.

One embodiment, as shown in the left diagram of fig. 4, includes a central nanostructure surrounded by 6 peripheral nanostructures at equal distances, and the peripheral nanostructures are uniformly distributed circumferentially to form a regular hexagon, which can also be understood as a combination of regular triangles formed by a plurality of nanostructures.

One embodiment, shown in the right diagram of fig. 4, is a central nanostructure surrounded by 4 peripheral nanostructures spaced equally apart from each other to form a square.

As shown in fig. 5, the nanostructure may be a polarization-dependent structure, such as nanofin and nanoelliptic cylinder, which exert a geometric phase on the incident light; the nanostructures may also be polarization-independent structures, such as nanocylinders and nanosquares, which impart a propagation phase to incident light.

For the superlens unit in the embodiment, based on the phase distribution of the surface nanostructure, the optical phase thereof at least satisfies the following formula:

wherein r is the distance from the center of the superlens to the center of any of the nanostructures; lambda is the wavelength of operation and,

and x and y are the coordinates of the mirror surface of the super lens, and f is the focal length of the super lens. The phase of the superlens may be expressed by higher order polynomials, including even and odd polynomials. In the embodiment of the present application, compared with formulas (1), (2), (3), (7), and (8), formulas (4), (5), and (6) can be applied not only to the case where even-order polynomials are satisfiedThe phase is optimized, the phase satisfying odd polynomial can be optimized without destroying the rotational symmetry of the phase of the super lens, and the optimization freedom degree of the super lens is obviously improved. It should be noted that in formulas (1), (2), (3), (7) and (8), a1 is less than zero; and in equations (4), (5) and (6), a2 is less than zero.

In a preferred embodiment, the support layer is quartz glass.

In a preferred embodiment, the reflective film is formed on the quartz glass surface in a deposition process. By applying a mask during deposition, a hole 11 is formed at the incident light of each detector cell, which hole 11 acts as an aperture stop intended to limit the incident light.

In a preferred embodiment, an adhesive layer is arranged between the superlens unit and the detection element, and the adhesive layer can be capable of transmitting radiation of an operating waveband and is filled at the periphery and the top of the detection element.

In a preferred embodiment, an opaque adhesive is used to bond the base 6 to the substrate 32 around the detector element, wherein the adhesive forms a gap in the space where the optical path on the top of the detector element may pass to ensure that the incident light can pass normally.

In a preferred embodiment, the structural units and the nanostructures are disposed in a direction of the substrate close to the source of the incident light.

In a preferred embodiment, the structuring unit and the nanostructures are arranged in the direction of the substrate close to the detection element.

In a preferred embodiment, the holes 11 are formed in the form of laser drilling.

In a preferred embodiment, according to an embodiment of the present application, the micro-nano structure may be formed of at least one of the following materials: titanium oxide, silicon nitride, gallium phosphide, aluminum oxide, hydrogenated amorphous silicon, and the like. For example, when the target wavelength band is visible light, the material of the micro-nano structure includes one or more of silicon nitride, titanium oxide, gallium nitride, gallium phosphide and hydrogenated amorphous silicon; when the target waveband is near infrared light, the material of the micro-nano structure comprises one or more of silicon nitride, titanium oxide, gallium nitride, gallium phosphide, hydrogenated amorphous silicon, amorphous silicon and crystalline silicon; when the target waveband is far infrared light, the material of the micro-nano structure comprises one or more of crystalline silicon, crystalline germanium, zinc sulfide and zinc selenide; when the target waveband is ultraviolet light, the material of the micro-nano structure comprises hafnium oxide.

In a preferred embodiment, the probe element 5 and the superlens unit are formed in a wafer-level package. Because the processing of the super surface is compatible with the processing technology of a semiconductor, compared with a micro lens array used in the prior art, the super lens array is easier to process, smaller in size magnitude and lower in cost, and can be used for wafer-level packaging with a CMOS or CCD which is also manufactured on the surface of a wafer, and meanwhile, the distortion problem caused by assembly errors can be reduced.

In a preferred embodiment, a protective layer made of transparent material, such as quartz glass, may be further added above the metal reflective film. It can be understood that the metal reflecting film is clamped inside the quartz glass layer, and the metal reflecting film has the effect of reflecting the outside light and the aperture diaphragm, can be protected and has strong robustness.

In a preferred embodiment, a spacer layer is arranged between the superlens unit and the detector, the spacer layer being used to control the distance between the superlens and the detector element. The spacing layer is transparent or arranged around the detection element in a surrounding mode. In a further preferred embodiment, the superlens unit, the spacer layer and the detecting element are assembled together by wafer-level packaging. In a further preferred embodiment, the encapsulation is by means of bonding.

In a preferred embodiment, a base is included for holding the detector element.

In a preferred embodiment, the structural unit is a regular hexagon, and each vertex and the central position of the regular hexagon are provided with at least one nano structure.

In a preferred embodiment, the structural unit is a square, and at least one nano-structure is arranged at each vertex and the central position of the square.

In a preferred embodiment, the nanostructure is a polarization-dependent structure or a polarization-independent structure;

wherein the polarization-dependent structure comprises a fin-shaped cylinder or an elliptic cylinder and the polarization-independent structure comprises a cylinder or a square cylinder.

In a preferred embodiment, the detector cells are square. And are densely packed in a rectangular array to form a detector array. It should be understood that the detector cells may also be of other close-packed or non-close-packed shapes, such as hexagonal, for example.

In a preferred embodiment, the detection element is a CMOS or CCD or the like.

In a preferred embodiment, the substrate of each superlens unit in the detector array is integrally formed. In the integrally formed super lens array, each super lens unit can share the same substrate, namely, the super surface units in different areas are etched on the surface of the same substrate by adopting the processes of photoetching and the like; or made using different substrates and tiled to form an array.

In a preferred embodiment, a filler material is disposed between the nanostructures. The filling material is arranged in the gaps between the nano-structures and can also cover the tops of the nano-structures.

Based on the above embodiments and their preferred embodiments, the present application changes the position of the converging lens in the existing design to be provided with an aperture stop, and sets a superlens below the converging lens, i.e. deflects the light, and makes the light incident on the detector at a zero-degree chief ray angle. The lens has the advantages that the maximum chief ray angle which can be tolerated in the traditional lens scheme is increased, the lens does not need to be translated, the design and the processing are simple, and in addition, the volume is additionally reduced.

The above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims (11)

1. A superlens-based detector array comprising detector cells; the detector unit comprises a reflecting film, a super lens unit and a detection element which are sequentially arranged along the vertical direction;

the reflective film is provided with an aperture for limiting incident radiation;

wherein the superlens unit includes a substrate, an

The structural units are arrayed on the surface of the substrate and consist of periodically arranged nano structures;

wherein the superlens cell is configured to: the angularly incident radiation is deflected and focused onto the detection element.

2. The superlens-based detector array of claim 1, wherein a support layer or support structure is disposed between the reflective film and the superlens unit, the support layer being transparent to incident radiation in the operating wavelength band.

3. The superlens-based detector array of claim 2, wherein the support layer is quartz glass, and the reflective film is deposited on the quartz glass surface.

4. A superlens-based detector array according to claim 1, wherein an adhesive layer is disposed between the superlens unit and the detection elements, the adhesive layer being transparent to radiation in the operating wavelength band and filling the periphery of the detection elements.

5. The superlens-based detector array of claim 1, wherein the detection elements and superlens units are formed in a wafer-level package.

6. The superlens-based detector array of claim 1, further comprising a mount for holding the detecting element.

7. The superlens-based detector array of claim 1, wherein the structural units are regular hexagons, and at least one nanostructure is disposed at each vertex and center of the regular hexagons.

8. The superlens-based detector array of claim 1, wherein the structural units are squares with at least one nanostructure disposed at each vertex and center of the squares.

9. The superlens-based detector array of claim 1, wherein the nanostructures are polarization-dependent structures or polarization-independent structures;

wherein the polarization-dependent structure comprises a fin-shaped cylinder or an elliptic cylinder and the polarization-independent structure comprises a cylinder or a square cylinder.

10. The superlens-based detector array of claim 1, wherein the base of each superlens unit in the detector array is integrally formed.

11. The superlens-based detector array of claim 1, wherein a filler material is disposed between the nanostructures.

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