CN114690387A - Variable focus optical system - Google Patents
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- CN114690387A CN114690387A CN202210439140.3A CN202210439140A CN114690387A CN 114690387 A CN114690387 A CN 114690387A CN 202210439140 A CN202210439140 A CN 202210439140A CN 114690387 A CN114690387 A CN 114690387A
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- 230000003287 optical effect Effects 0.000 title claims abstract description 157
- 239000002086 nanomaterial Substances 0.000 claims description 44
- 239000000463 material Substances 0.000 claims description 24
- 239000000758 substrate Substances 0.000 claims description 17
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 14
- 229910021417 amorphous silicon Inorganic materials 0.000 claims description 14
- 230000008033 biological extinction Effects 0.000 claims description 7
- 239000005331 crown glasses (windows) Substances 0.000 claims description 7
- 229910021419 crystalline silicon Inorganic materials 0.000 claims description 7
- 239000005308 flint glass Substances 0.000 claims description 7
- 239000005350 fused silica glass Substances 0.000 claims description 7
- 230000010287 polarization Effects 0.000 claims description 7
- 239000010980 sapphire Substances 0.000 claims description 7
- 229910052594 sapphire Inorganic materials 0.000 claims description 7
- 230000005855 radiation Effects 0.000 claims description 6
- 239000000945 filler Substances 0.000 claims description 4
- 239000006185 dispersion Substances 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 3
- 239000013585 weight reducing agent Substances 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 23
- 238000003384 imaging method Methods 0.000 description 5
- 210000001747 pupil Anatomy 0.000 description 4
- 238000010276 construction Methods 0.000 description 3
- 238000005457 optimization Methods 0.000 description 3
- 238000002834 transmittance Methods 0.000 description 3
- 238000009434 installation Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B15/00—Optical objectives with means for varying the magnification
- G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
- G02B15/143—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having three groups only
- G02B15/1431—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having three groups only the first group being positive
- G02B15/143105—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective having three groups only the first group being positive arranged +-+
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B3/00—Simple or compound lenses
- G02B3/02—Simple or compound lenses with non-spherical faces
- G02B3/08—Simple or compound lenses with non-spherical faces with discontinuous faces, e.g. Fresnel lens
Abstract
The embodiment of the application provides a variable-focus optical system, and belongs to the technical field of optics. The variable focal optical system includes, in order from an object side to an image side along an optical path: the first lens group is fixed in position and has positive focal power; a second lens group, which is adjustable in position along the optical axis direction and has negative focal power; the third lens group is fixed in position and has positive focal power; wherein at least the second lens and/or the third lens comprises a super lens, and the phase of the super lens at least satisfies any one of the following formulas:
wherein r is the coordinate of the radius direction of the super lens, lambda is the working wavelength,
is an arbitrary constant phase, ai、aij、bijIs the index, (x, y) is the superlens mirror coordinates, and f is the focal length of the individual superlens. The optical system promotes miniaturization and weight reduction of the continuous zoom system.
Description
Technical Field
The application relates to the technical field of optics, in particular to a variable-focus optical system.
Background
Zooming refers to the optical system varying the focal length over a range to image objects at different distances.
The existing variable-focus optical system is changed by changing the relative position of each refractive lens group in the system. As shown in fig. 1, the prior art zoom system has a complicated structure, and the optical path is usually changed by means of a prism and a reflective lens to form a periscopic structure, so as to reduce the length of the entire zoom system in the optical incident direction, thereby achieving the purpose of reducing the volume. However, as the requirement of users for the imaging quality is higher and higher, the number of lenses of the variable focus optical system in the prior art is higher and higher, the size is larger and the weight is heavier and heavier.
Therefore, there is a demand for a variable focus optical system that is small and lightweight.
Disclosure of Invention
In order to solve the technical problem that a variable-focus optical system in the prior art is large in size and heavy in weight, the embodiment of the application provides a variable-focus optical system.
An embodiment of the present application provides a variable focus optical system, which sequentially includes, from an object side to an image side along a light path:
a first lens group fixed in position and having positive power;
a second lens group, which is position-adjustable in the optical axis direction and has negative power;
a third lens group that is fixed in position and has positive power;
wherein at least the second lens and/or the third lens comprises a super lens, and the phase of the super lens at least satisfies any one of the following formulas:
wherein r is the coordinate of the radius direction of the super lens, lambda is the working wavelength,
is an arbitrary constant phase, ai、aij、bijIs the coefficient, (x, y) is the superlens mirror coordinate, and f is the focal length of the single superlens.
Optionally, the first lens group and the third lens group are refractive lenses, and the second lens group includes a superlens.
Optionally, the first lens group and the second lens group are refractive lenses, and the third lens group comprises a superlens.
Optionally, the first lens group, the second lens group and the third lens group each comprise a superlens.
Optionally, the total optical focal length, the back intercept and the magnification of the variable-focus optical system satisfy the following relationship:
s21＝-φt；
s11＝d2d3φ1φ2-(d2+d3)φ1-d3φ2+1；
s22＝d2d3φ2φ3-(d2+d3)φ3-d2φ2+1；
wherein d is1Distance of object plane to said first lens group, d2Is the distance between the first lens group and the second lens group, d3Is the distance between the second lens group and the third lens group; phi1、Φ2、Φ3The powers of the first lens group, the second lens group, and the third lens group, respectively.
Optionally, the variable focus optical system further comprises a fourth lens group;
the fourth lens group is provided between the second lens group and the third lens group, and is position-adjustable in an optical axis direction, having positive power;
wherein at least the second lens group and/or the third lens group and/or the fourth lens group comprises a superlens, and the phase of the superlens at least satisfies any one of the following formulas:
wherein r is the coordinate of the radius direction of the super lens, lambda is the working wavelength,
is an arbitrary constant phase, ai、aij、bijIs the coefficient, (x, y) is the superlens mirror coordinate, and f is the focal length of the single superlens.
Optionally, the first lens group and the third lens group are refractive lenses, and the second lens group and the fourth lens group include superlenses.
Optionally, the first lens group, the third lens group, the second lens group and the fourth lens group each comprise a superlens.
Optionally, the second lens group and the fourth lens group satisfy:
wherein m is2And m4Respectively being the second lens group and theMagnification of the fourth zoom group, f2And f4The focal lengths of the second lens group and the fourth lens group, respectively, and d is a differential sign.
Optionally, the operating bands of the variable focus optical system include a visible light band, a near infrared band, a mid-infrared band, a far infrared band, an ultraviolet band, a deep ultraviolet band, and an extreme deep ultraviolet band.
Optionally, the operating band of the variable focus optical system comprises 905nm ± 20nm, 940nm ± 20nm or 1550nm ± 20 nm.
Optionally, the superlens comprises:
the micro-nano structure layer is arranged on one side of the substrate layer;
the micro-nano structure layer comprises superstructure units which are periodically arranged, and micro-nano structures are arranged at the vertexes and/or the central positions of the superstructure units.
Optionally, the period of the micro-nano structure is greater than or equal to 0.3 lambdacAnd is less than or equal to 2 lambdac；
Wherein λ iscIs the center wavelength of the operating band; λ when the operating band is multibandcIs the center wavelength of the shortest wavelength operating band.
Optionally, the height of the micro-nano structure is greater than or equal to 0.3 lambdacAnd is less than or equal to 5 lambdac；
Wherein λ iscIs the center wavelength of the operating band; λ when the operating band is multibandcIs the center wavelength of the shortest wavelength operating band.
Optionally, the shape of the superstructure unit comprises a combination of one or more of a regular hexagon, a regular quadrangle, or a fan.
Optionally, the shape of the micro-nano structure comprises a polarization sensitive structure.
Optionally, the shape of the micro-nano structure comprises a polarization insensitive structure.
Optionally, an extinction coefficient of the micro-nano structure to radiation of a working waveband is less than 0.01.
Optionally, the substrate material comprises one or more of fused silica, quartz glass, crown glass, flint glass, sapphire, crystalline silicon, amorphous silicon, and hydrogenated amorphous silicon.
Optionally, the material of the micro-nano structure is one or more of fused quartz, quartz glass, crown glass, flint glass, sapphire, crystalline silicon, amorphous silicon and hydrogenated amorphous silicon.
Optionally, the substrate and the micro-nano structure are made of different materials.
Optionally, the superlens further comprises a filler material;
the extinction coefficient of the filling material to the radiation of the working waveband is less than 0.01.
Optionally, the superlens and the refractive lens are required to satisfy, in terms of power and dispersion:
wherein the content of the first and second substances,
the phase of a refractive lens in the variable-focus optical system;
the phase of a superlens in the variable-focus optical system; v. ofiThe abbe number of each lens group in the variable-focus optical system.
In the variable-focus optical system provided by the embodiment of the application, at least the second lens group and/or the third lens group comprise the super lens, and the position of the second lens group on the optical axis is adjustable, so that the continuous adjustment of the focal length of the system is realized. According to the variable-focus optical system provided by the embodiment of the application, all the lens groups are located on the same axis, and compared with a periscopic structure, the variable-focus optical system realizes miniaturization and light weight.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments or the background art of the present application, the drawings required to be used in the embodiments or the background art of the present application will be described below.
Fig. 1 shows a schematic diagram of a prior art variable focus optical system;
FIG. 2 illustrates a schematic diagram of a variable focus optical system provided by an embodiment of the present application;
fig. 3 is a schematic diagram illustrating an alternative structure of the variable focus optical system provided in the embodiment of the present application;
fig. 4 is a schematic diagram illustrating an alternative structure of a variable focus optical system provided in an embodiment of the present application;
FIG. 5 is a schematic diagram of yet another alternative construction of a variable focus optical system provided by an embodiment of the present application;
FIG. 6 is a schematic diagram of yet another alternative construction of a variable focus optical system provided by an embodiment of the present application;
FIG. 7 is a schematic diagram of yet another embodiment of a variable focus optical system provided by an embodiment of the present application;
FIG. 8 is a schematic diagram of yet another embodiment of a variable focus optical system provided by an embodiment of the present application;
fig. 9 is a schematic diagram illustrating yet another alternative structure of a variable focus optical system provided by an embodiment of the present application;
FIG. 10 is a schematic diagram of yet another alternative construction of a variable focus optical system provided by an embodiment of the present application;
FIG. 11 is a perspective view of another alternative micro-nano structure of a superlens provided by an embodiment of the present application;
FIG. 12 illustrates a perspective view of another alternative micro-nano structure of a superlens provided by an embodiment of the present application;
FIG. 13 shows an alternative schematic diagram of a superstructure unit provided by embodiments of the present application;
FIG. 14 shows yet another alternative schematic diagram of a superstructure unit provided by embodiments of the present application;
FIG. 15 shows yet another alternative schematic diagram of a superstructure unit provided by embodiments of the present application;
FIG. 16 is a schematic diagram illustrating an alternative configuration of a variable focus optical system provided by an embodiment of the present application at a short focal length;
fig. 17 is a schematic diagram illustrating an alternative structure of a variable focus optical system provided in an embodiment of the present application at a long focal length;
FIG. 18 illustrates the modulation transfer function of a variable focus optical system provided by an embodiment of the present application at short focal lengths;
FIG. 19 is a graph showing the modulation transfer function at long focal length for yet another variable focus optical system provided by an embodiment of the present application;
FIG. 20 is a schematic diagram illustrating an alternative configuration of a variable focus optical system provided by an embodiment of the present application at a short focal length;
FIG. 21 is a schematic diagram illustrating an alternative configuration of a variable focus optical system provided by an embodiment of the present application at a long focal length;
FIG. 22 illustrates the modulation transfer function of yet another variable focus optical system provided by an embodiment of the present application at short focal lengths;
FIG. 23 illustrates the modulation transfer function at a long focal length for yet another variable focus optical system provided by an embodiment of the present application;
FIG. 24 illustrates the modulation transfer function at short focal lengths for a variable focus optical system provided by an embodiment of the present application;
fig. 25 shows the modulation transfer function of the variable focus optical system provided by the embodiments of the present application at long focal lengths.
The reference numerals in the drawings denote:
10-a first lens group; 20-a second lens group; 30-a third lens group; 40-a fourth lens group.
Detailed Description
The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. The present teachings are suitable for incorporation on many different types of optical devices. For purposes of illustration, the supersurfaces provided herein are shown as monolithic planar superlenses. However, the present teachings are equally applicable to other combinations of angles.
Example embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope to those skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known methods, well-known device structures, and well-known technologies are not described in detail.
When an element or layer is referred to as being "on," "engaged to," "connected to" or "coupled to" another element or layer, it can be directly on, engaged, connected or coupled to the other element or layer or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," or "directly engaged with," "directly connected to," or "directly coupled to" another element or layer, there are no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in the same manner (e.g., "between …" versus "directly between …", "adjacent" versus "directly adjacent", etc.). As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as "first," "second," and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.
The variable focus optical system in the prior art, as shown in fig. 1, cannot reduce the number of lenses of the optical system, but needs to increase a prism and a reflection lens in order to reduce the installation space occupied by the optical system. Especially miniaturized and lightweight devices (e.g., mobile phones, drones, etc.) have not been able to support optical systems that can continuously zoom due to limitations in installation space. For example, the optical zoom principle of the current mobile phone is to switch from the main lens to the telephoto lens, so that the mobile phone can only have better imaging performance in a specific focal segment.
The embodiment of the application provides a variable-focus optical system, and the working principle of the variable-focus optical system is shown in fig. 2. As shown in fig. 3 to 5, the variable focal optical system includes, in order from the object side to the image side along the optical path, a first lens group 10, a second lens group 20, and a third lens group 30. Wherein, the position of the first lens group 10 is fixed and has positive focal power; the second lens group 20 is adjustable in position in the optical axis direction, and has negative power; the third lens group 30 is fixed in position and has positive power. Alternatively, the second lens group 20 may be displaced in a direction perpendicular to the optical axis to achieve optical anti-shake.
In the optical system, at least the second lens group 20 and/or the third lens group 30 include a superlens. The phase of the superlens at least satisfies any one of the following formulas:
wherein r is the coordinate of the radius direction of the super lens, lambda is the working wavelength,
is an arbitrary constant phase, ai、aij、bijIs the coefficient, (x, y) is the superlens mirror coordinate, and f is the focal length of the single superlens. The phase of the superlens may be expressed by a high order polynomial. Wherein, formula (1) a1And (2) a2And the phase position corresponding to the odd polynomial can be optimized by the formula (2) without damaging the rotational symmetry, so that the optimization freedom of the superlens is greatly increased, and the optimization accuracy of the superlens is also improved. Equation (3) allows optimization of the superlens for non-planar substrates.
Referring to fig. 2, the first lens group 10 has positive refractive power, so that light rays in each field of view can uniformly enter the variable focal length optical system. The second lens group 20 is used for zooming, and can balance the refractive power distribution of the variable-focus optical system, and perform aberration correction on the light rays converged by the first lens group 10. The third lens group 30 converges the light passing through the second lens group 20 to form an image on an image plane. The third lens group 30 is used to ensure that the image-side focal plane of the variable focal length optical system is stable when the second lens group 20 is moved. Continuous zooming of the entire optical system can be achieved by adjusting the position of the second lens group 20 along the optical axis.
According to an embodiment of the present application, as shown in fig. 3, the first lens group 10 and the third lens group 30 are refractive lenses, and the second lens group 20 includes a superlens. In some embodiments of the present application, as shown in fig. 4, the first lens group 10 and the second lens group 20 are refractive lenses, and the third lens group 30 includes a superlens. For another example, fig. 5 shows a case where the second lens group 20 and the third lens group 30 include a superlens, and the first lens group 10 is a refractive lens. In some exemplary embodiments of the present application, as shown in fig. 6, the first lens group 10, the second lens group 20, and the third lens group 30 each include a superlens. The lens group including the superlens in the lens group may be a single superlens, or may be a combination of a superlens and a refractive lens, or a superlens and a superlens, and a single superlens is preferable.
Further, in order to ensure that the variable focal length optical system provided by the embodiment of the present application has good imaging performance when the second lens group 20 moves, the total optical focal length, the back focal length, and the magnification of the variable focal length optical system satisfy the following relationship:
s21＝-φt； (8)
s11＝d2d3φ1φ2-(d2+d3)φ1-d3φ2+1； (9)
s22＝d2d3φ2φ3-(d2+d3)φ3-d2φ2+1；(11)
wherein d is1Distance of object plane to first lens group 10, d2Is a first lens group 10 and a second lens group 20Distance between d3Is the distance between the second lens group 20 and the third lens group 30; d4Is the back intercept of the variable focus optical system; phi is a1、φ2、φ3The powers of the first lens group 10, the second lens group 20, and the third lens group 30, respectively; phi is atIs the total phase of the variable focus optical system.
Further, as shown in fig. 7 to 10, the variable focus optical system provided in the embodiment of the present application further includes a fourth lens group 40. Wherein the fourth lens group 40 is disposed between the second lens group 20 and the third lens group 30, and the fourth lens group 40 is position-adjustable in the optical axis direction, having positive power.
In the variable-focus optical system, at least the second lens group 20 and/or the third lens 30 and/or the fourth lens group 40 comprises a super lens, and the phase of the super lens at least satisfies any one of the following formulas:
wherein r is the coordinate of the radius direction of the super lens, λ is the working wavelength, φ 0 is any constant phase, ai, aij, bij are coefficients, (x, y) are the mirror coordinates of the super lens, and f is the focal length of the single super lens. Wherein a2 in the formulas (1) a1 and (2) is less than 0.
Specifically, referring to fig. 7 and 8, in the variable focal length optical system, the second lens group 20 and the fourth lens group 30 are both movable lens groups. Wherein the second lens group 20 has negative focal power for compensating conjugate point shift to form compensation for the back focal length of the variable focal length optical system; and the fourth lens group 40 has positive power and functions to vary the focal length. Illustratively, when the second lens group 20 moves toward the image side of the optical system while the fourth lens group 40 moves toward the object side of the optical system, the focal length of the optical system becomes smaller.
According to an embodiment of the present application, as shown in fig. 9, the first lens group 10 and the third lens group 30 in the variable focal optical system are refractive lenses, and the second lens group 20 and the fourth lens group 40 include superlenses. Alternatively, as shown in fig. 10, the first to fourth lens groups in the variable focal length optical system each include a superlens.
Further, the second lens group 20 and the fourth lens group 40 satisfy:
wherein m is2And m4Magnification, f, of the second lens group 20 and the fourth zoom group 40, respectively2And f4The focal lengths of the second lens group 20 and the fourth lens group 40, respectively, and d is a differential sign.
According to an embodiment mode of the present application, the operating bands of the variable focus optical system include a visible light band, a near infrared band, a mid infrared band, a far infrared band, an ultraviolet light band, a deep ultraviolet light band, and an extreme deep ultraviolet light band. Illustratively, the operating band of the variable focus optical system includes 905nm ± 20nm, 940nm ± 20nm, or 1550nm ± 20 nm.
According to an embodiment of the present application, when the variable-focus optical system includes refractive lenses, all refractive lenses need to satisfy the following formula in terms of power and dispersion:
wherein the content of the first and second substances,
the phase of a refractive lens in the variable-focus optical system;
the phase of a superlens in the variable-focus optical system; v. ofiThe abbe number of each lens group in the variable-focus optical system.
Next, referring to fig. 11 to 15, the superlens employed in the embodiment of the present application will be described in detail.
The superlens is a specific application of a supersurface, which modulates the phase, amplitude and polarization of incident light by periodically arranged sub-wavelength-sized nanostructures. As shown in fig. 13 to 14, the superlens includes a substrate and a micro-nano structure layer disposed on one side of the substrate layer; the micro-nano structure layer comprises periodically arranged superstructure units, and micro-nano structures are arranged at the vertexes and/or the central positions of the superstructure units. In some cases, one side of the substrate is provided with a micro-nano structure layer. In some cases, the micro-nano structure layer is arranged on both sides of the substrate.
Fig. 11 and 12 are perspective views illustrating a micro-nano structure of a superlens used in a variable focus optical system provided by an embodiment of the present application. Optionally, air or other transparent or semitransparent materials in the working waveband can be filled between the micro-nano structures on the super lens. According to the embodiment of the application, the absolute value of the difference between the refractive index of the filled material and the refractive index of the micro-nano structure is greater than or equal to 0.5. As shown in fig. 11, the micro-nano structure may be a polarization sensitive structure, which imposes a geometric phase on the incident light. For example, an elliptic cylinder, a hollow elliptic cylinder, an elliptic hole shape, a hollow elliptic hole shape, a rectangular cylinder, a rectangular hole shape, a hollow rectangular cylinder, a hollow rectangular hole, and the like. As shown in fig. 12, the micro-nano structure may be a polarization insensitive structure that imposes a propagation phase on the incident light. For example, a cylindrical shape, a hollow cylindrical shape, a circular hole shape, a hollow circular hole shape, a square cylindrical shape, a square hole shape, a hollow square cylindrical shape, a hollow square hole shape, and the like.
As shown in fig. 13, according to an embodiment of the present application, the superstructure units may be arranged in a fan shape. As shown in fig. 14, according to an embodiment of the present application, the superstructure units may be arranged in an array of regular hexagons. Further, as shown in fig. 15, according to an embodiment of the present application, the superstructure units may be arranged in a square array. Those skilled in the art will recognize that the superstructure units included in the micro-nano structure layer may also include other forms of array arrangements, and all such variations are within the scope of the present application.
Optionally, the period of the micro-nano structure is greater than or equal to 0.3 lambdacAnd is less than or equal to 2 lambdac(ii) a Wherein λ iscIs the center wavelength of the operating band; λ when the operating band is multibandcIs the center wavelength of the shortest wavelength operating band. Optionally, the height of the micro-nano structure is greater than or equal to 0.3 lambdacAnd is less than or equal to 5 lambdac(ii) a Wherein λ iscIs the center wavelength of the operating band; when the operating band is multiband, λcIs the center wavelength of the shortest wavelength operating band.
According to an embodiment of the application, the micro-nano structure is an all-dielectric structural unit. The micro-nano structure is made of a material with high transmittance in the working waveband of the variable-focus optical system. Optionally, an extinction coefficient of the micro-nano structure to radiation of a working waveband is less than 0.01. Illustratively, the material of the micro-nano structure includes fused quartz, quartz glass, crown glass, flint glass, sapphire, crystalline silicon, amorphous silicon, hydrogenated amorphous silicon and the like.
Optionally, the material of the substrate is different from the material of the micro-nano structure. The material of the substrate is a material with high transmittance in the working waveband of the variable-focus optical system. Optionally, an extinction coefficient of the micro-nano structure to radiation of a working waveband is less than 0.01. Illustratively, the substrate material may be fused silica, quartz glass, crown glass, flint glass, sapphire, crystalline silicon, amorphous silicon, hydrogenated amorphous silicon, or the like.
According to an embodiment of the present application, the filling material is a material with high transmittance in the working band, and optionally, the extinction coefficient of the filling material to the working band is less than 0.01. Illustratively, the filler material may be fused silica, quartz glass, crown glass, flint glass, sapphire, crystalline silicon, amorphous silicon, hydrogenated amorphous silicon, and the like. Preferably, the filler structure is of a different material than the base material, the nanostructure material.
Example 1
Exemplary, embodiments of the present application provide a variable focus optical system as shown in fig. 16 and 17. In the variable focal length optical system, the first to third lens groups are all superlenses. The parameters of the variable focus optical system shown in fig. 16 and 17 include: an Entrance Pupil Diameter (EPD, entry Pupil Diameter), a Short Focal Length (SFL, Short Focal Length), a Long Focal Length (LFL, Long Focal Length), a Short Focal angle (S-FOV) corresponding to a Short focus, a Long Focal angle (L-FOV) corresponding to a Long focus, and a Back Focal Length (BFL, Back Focal Length). Fig. 16 is a schematic structural diagram illustrating a variable focus optical system provided by an embodiment of the present application at a short focal length. Fig. 17 is a schematic structural diagram illustrating a variable focus optical system provided in an embodiment of the present application at a long focal length. When the variable focal length optical system is in the long focal length, the second lens group 20 is located closer to the object side than the short focal length.
The parameters of the variable focus optical system are shown in table 1. The imaging performance of the variable focal length optical system at the short focal length and the long focal length is shown in fig. 18 and fig. 19, respectively. As shown in fig. 18 and 19, the modulation transfer functions of the variable-focus optical system at both the 0-field and the 1-field do not exceed the diffraction limit, and the image quality of the entire system is good at the cutoff frequency of 200 lp/mm.
TABLE 1
Example 2
Exemplary, embodiments of the present application further provide a variable focus optical system as shown in fig. 20 and 21. In the variable focal length optical system, the first and second lens groups are each a superlens, and the third lens group 30 is a refractive lens. The parameters of the variable focus optical system shown in fig. 19 and 20 include: an Entrance Pupil Diameter (EPD, entry Pupil Diameter), a Short Focal Length (SFL, Short Focal Length), a Long Focal Length (LFL, Long Focal Length), a Short Focal angle (S-FOV) corresponding to a Short focus, a Long Focal angle (L-FOV) corresponding to a Long focus, and a Back Focal Length (BFL, Back Focal Length). Fig. 20 is a schematic diagram illustrating a structure of a variable focus optical system provided in an embodiment of the present application at a short focal length. Fig. 21 is a schematic diagram showing a structure of a variable focus optical system provided in an embodiment of the present application at a long focal length. When the variable focal length optical system is in the long focal length, the second lens group 20 is located closer to the object side than the short focal length.
The parameters of the variable focus optical system are shown in table 2. The imaging performance of the variable focal length optical system at the short focal length and the long focal length is shown in fig. 22 and 23, respectively. As shown in fig. 22 and 23, the modulation transfer functions of the variable-focus optical system at both the 0-field and the 1-field do not exceed the diffraction limit, and the image quality of the entire system is good at the cutoff frequency of 30 lp/mm.
TABLE 2
Example 3
Illustratively, as shown in fig. 7, the present embodiment further provides a variable focus optical system including a first lens group 10, a second lens group 20, a third lens group 30, and a fourth lens group 40. The parameters of the variable focus optical system are shown in table 4. Fig. 24 and 25 are distribution diagrams showing modulation transfer function diagrams at short focal length and long focal length of the variable focus optical system, and it can be seen that the image quality of the whole system is good at the cut-off frequency of 200 lp/mm.
In summary, in the variable-focus optical system provided by the embodiment of the present application, at least the second lens group and/or the third lens group includes a super lens, and the position of the second lens group on the optical axis is adjustable, so that the continuous adjustability of the focal length of the system is realized. According to the variable-focus optical system provided by the embodiment of the application, all the lens groups are located on the same axis, and compared with a periscopic structure, the variable-focus optical system realizes miniaturization and light weight.
The above description is only a specific implementation of the embodiments of the present application, but the scope of the embodiments of the present application is not limited thereto, and any person skilled in the art can easily conceive of changes or substitutions within the technical scope of the embodiments disclosed in the present application, and all the changes or substitutions should be covered by the scope of the embodiments of the present application. Therefore, the protection scope of the embodiments of the present application shall be subject to the protection scope of the claims.
Claims (24)
1. A variable focal length optical system comprising, in order from an object side to an image side along an optical path:
a first lens group (10), the first lens group (10) being fixed in position and having positive optical power;
a second lens group (20), the second lens group (20) being position-adjustable in the optical axis direction, having negative power;
a third lens group (30), the third lens group (30) being fixed in position and having positive optical power;
wherein at least the second lens group (20) and/or the third lens group (30) comprises a superlens, the phase of which satisfies at least any one of the following formulas:
wherein r is the coordinate of the radius direction of the super lens, lambda is the working wavelength,
is an arbitrary constant phase, ai、aij、bijIs the coefficient, (x, y) is the superlens mirror coordinate, and f is the focal length of the single superlens.
2. The variable focus optical system of claim 1, wherein the first lens group (10) and the third lens group (30) are refractive lenses, and wherein the second lens group (20) comprises a superlens.
3. The variable focus optical system of claim 1, wherein the first lens group (10) and the second lens group (20) are refractive lenses, and wherein the third lens group (30) comprises a superlens.
4. The variable focus optical system of claim 1, wherein the first lens group (10), the second lens group (20), and the third lens group (30) each comprise a superlens.
5. The variable focus optical system of claim 1 wherein the total optical focal length, back intercept and magnification of the variable focus optical system satisfy the following relationship:
s21＝-φt；
s11＝d2d3φ1φ2-(d2+d3)φ1-d3φ2+1；
s22＝d2d3φ2φ3-(d2+d3)φ3-d2φ2+1；
wherein, d1Is the distance of the object plane from the first lens group (10), d2Is the distance between the first lens group (10) and the second lens group (20), d3Is the distance between the second lens group (20) and the third lens group (30); d4Is the back intercept of the variable focus optical system; phi1、Φ2、Φ3The powers of the first lens group (10), the second lens group (20) and the third lens group (30), respectively.
6. The variable focus optical system of claim 1, further comprising a fourth lens group (40);
the fourth lens group (40) is disposed between the second lens group (20) and the third lens group (30), and the fourth lens group (40) is position-adjustable in the optical axis direction, having positive power;
wherein at least the second lens group (20) and/or the third lens group (30) and/or the fourth lens group (40) comprises a superlens, the phase of which at least satisfies any one of the following formulas:
wherein r is the coordinate of the radius direction of the super lens, lambda is the working wavelength,
is an arbitrary constant phase, ai、aij、bijIs the coefficient, (x, y) is the superlens mirror coordinate, and f is the focal length of the single superlens.
7. The variable focus optical system of claim 6, wherein the first lens group (10) and the third lens group (30) are refractive lenses, and the second lens group (20) and the fourth lens group (40) comprise superlenses.
8. The variable focus optical system of claim 6, wherein the first lens group (10), the third lens group (30), the second lens group (20), and the fourth lens group (40) each comprise a superlens.
9. Variable focus optical system according to claim 6, wherein the second lens group (20) and the fourth lens group (40) satisfy:
wherein m is2And m4Magnification, f, of the second lens group (20) and the fourth lens group (40), respectively2And f4The focal lengths of the second lens group (20) and the fourth lens group (40), respectively, and d is a differential sign.
10. The variable focus optical system of any of claims 1 to 9 wherein the operating bands of the variable focus optical system include a visible band, a near infrared band, a mid infrared band, a far infrared band, an ultraviolet band, a deep ultraviolet band, and an extreme deep ultraviolet band.
11. The variable focus optical system of claim 10 wherein the operating band of the variable focus optical system comprises 905nm + 20nm, 940nm + 20nm, or 1550nm + 20 nm.
12. The variable focus optical system of any of claims 1 to 9 wherein said superlens comprises:
the micro-nano structure layer is arranged on one side of the substrate;
the micro-nano structure layer comprises superstructure units which are periodically arranged, and micro-nano structures are arranged at the vertexes and/or the central positions of the superstructure units.
13. The variable focus optical system of claim 12 wherein the period of the superstructure unit is greater than or equal to 0.3 λcAnd is less than or equal to 2 lambdac；
Wherein λ iscIs the center wavelength of the operating band; λ when the operating band is multibandcIs the center wavelength of the shortest wavelength operating band.
14. The variable focus optical system of claim 12 wherein the height of the micro-nano structure is greater than or equal to 0.3 λcAnd is less than or equal to 5 lambdac；
Wherein λ iscIs the center wavelength of the operating band; λ when the operating band is multibandcIs the center wavelength of the shortest wavelength operating band.
15. The variable focus optical system of claim 12 wherein the superstructure unit has a shape comprising a combination of one or more of a regular hexagon, a regular quadrilateral, or a sector.
16. The variable focus optical system of claim 12 wherein the micro-nano structures comprise polarization sensitive structures.
17. The variable focus optical system of claim 12 wherein the shape of the micro-nano structures comprises polarization insensitive structures.
18. The variable focus optical system of claim 12 wherein the micro-nano structure has an extinction coefficient of less than 0.01 for radiation in the operating band.
19. The variable focus optical system of claim 12 wherein the substrate comprises one or more of fused silica, quartz glass, crown glass, flint glass, sapphire, crystalline silicon, amorphous silicon, and hydrogenated amorphous silicon.
20. The variable focus optical system of claim 12 wherein the micro-nano structure is made of one or more of fused silica, quartz glass, crown glass, flint glass, sapphire, crystalline silicon, amorphous silicon, and hydrogenated amorphous silicon.
21. The variable focus optical system of claim 19 or 20 wherein the substrate and the micro-nano structure are of different materials.
22. The variable focus optical system of claim 12 wherein said superlens further comprises a filler material;
the extinction coefficient of the filling material to the radiation of the working waveband is less than 0.01.
23. The variable focus optical system of claim 12 wherein said substrate comprises a curved substrate;
and the height axis of the micro-nano structure is vertical to a tangent plane of the position of the micro-nano structure on the curved surface substrate.
24. The variable focus optical system of any of claims 1 to 3, 5 to 7 or 9 wherein said superlens and said refractive lens are such as to satisfy, in terms of optical power and dispersion:
wherein the content of the first and second substances,
the phase of a refractive lens in the variable-focus optical system;
the phase of a superlens in the variable-focus optical system; v. ofiThe abbe number of each lens group in the variable focal length optical system.
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| CN202210439140.3A CN114690387A (en) | 2022-04-25 | 2022-04-25 | Variable focus optical system |
| PCT/CN2023/090233 WO2023207888A1 (en) | 2022-04-25 | 2023-04-24 | Zoom optical system |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN116661158A (en) * | 2023-07-31 | 2023-08-29 | 歌尔光学科技有限公司 | Optical machine illumination module, projection display system and projection equipment |
| WO2023207888A1 (en) * | 2022-04-25 | 2023-11-02 | 深圳迈塔兰斯科技有限公司 | Zoom optical system |
| US11927769B2 (en) | 2022-03-31 | 2024-03-12 | Metalenz, Inc. | Polarization sorting metasurface microlens array device |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117406401B (en) * | 2023-12-16 | 2024-03-08 | 武汉二元科技有限公司 | External lens of folding and super-mixing mobile phone |
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| US20060056067A1 (en) * | 2004-08-26 | 2006-03-16 | Tetsuya Yanai | Optical system and imaging system incorporating it |
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| WO2023207888A1 (en) * | 2022-04-25 | 2023-11-02 | 深圳迈塔兰斯科技有限公司 | Zoom optical system |
| CN116661158A (en) * | 2023-07-31 | 2023-08-29 | 歌尔光学科技有限公司 | Optical machine illumination module, projection display system and projection equipment |
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| WO2023207888A1 (en) | 2023-11-02 |
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