Optical lens system and imaging system including the same

Abstract

An example apparatus includes a lens system. The lens system includes a first lens group, a second lens group, and an aperture stop layer disposed between the first lens group and the second lens group. Each of the first lens group and the second lens group includes at least one respective lens, and at least one of the first lens group or the second lens group includes at least one of a super optical element (MOE) lens or a diffractive optical element (DOE) lens. Receiving and projection imaging systems including the lens systems and associated methods are also described.

Description

Technical Field

[0001] The present disclosure relates to optical lens systems and imaging systems including optical lens systems. Background Art

[0002] Some lenses, such as meta-optical elements (MOEs) and diffractive optical elements (DOEs), employ planar optical techniques. For example, a MOE has a metasurface that includes distributed small sub-wavelength structures (e.g., nanostructures or other meta-atoms) arranged to interact with light in a specific way. The meta-atoms can interact with light waves individually and / or collectively to change the local amplitude, local phase, or both of the incident light waves. Similarly, a DOE has a microstructure pattern that changes and controls the phase of the incident light waves. By varying the microstructure, a DOE has the potential to produce a range of beam intensity distributions or beam shapes. For example, a MOE or DOE can be used in optical applications to take advantage of the flat surface and reduced thickness compared to a classical curved refractive lens.

[0003] However, planar optical lenses such as MOEs and DOEs are susceptible to large dispersion because diffraction phenomena are highly wavelength-dependent. If such dispersion is not addressed, imaging systems containing such optical elements may have large chromatic aberrations, which results in a more limited (i.e., narrow) operating spectral bandwidth (e.g., only a few nanometers). Such constraints impose severe restrictions on the choice of light sources for scene illumination and can limit the overall efficiency of these imaging systems. Summary of the invention

[0004] The present disclosure describes optical lens systems and imaging systems incorporating optical lens systems, and associated methods.

[0005] For example, in one aspect, the present disclosure describes a device including a lens system. The lens system includes a first lens group, a second lens group, and an aperture stop disposed between the first lens group and the second lens group. Each of the first lens group and the second lens group includes at least one respective lens, and at least one of the first lens group or the second lens group includes at least one of a meta-optical element (MOE) lens or a diffractive optical element (DOE) lens.

[0006] Some embodiments include one or more of the following features. For example, in some embodiments, each of the first lens group and the second lens group includes at least one of a MOE lens or a DOE lens. In some embodiments, each of the first lens group and the second lens group includes a corresponding MOE lens. In some cases, each of the MOE lenses includes a corresponding metasurface on a corresponding substrate, and there is a corresponding gap between the aperture stop and each of the substrates. In some cases, each of the MOE lenses includes a corresponding metasurface on a corresponding substrate, and there is a gap between the aperture stop and at least one of the substrates. In some cases, each of the MOE lenses includes a corresponding metasurface on a corresponding substrate, and the corresponding back sides of the substrates are attached to each other. In some embodiments, each of the first lens group and the second lens group includes a corresponding DOE lens.

[0007] In some embodiments, at least one of the first lens group or the second lens group includes a plurality of lenses. Depending on the application, the total focal power of the first lens group can be the same as or different from the total focal power of the second lens group. Furthermore, in some cases, for example, the lateral chromatic aberration of the lens system is less than ten times the radius of the Airy disk of the lens system.

[0008] In some embodiments, the device further includes one or more image sensors, and the one or more image sensors are configured to capture an image of an object based on light emitted by or reflected from the object and passing through the lens system. In some cases, the second lens group is closer to the one or more image sensors than the first lens group, and the equivalent focal length of the second lens group is greater than 25% of the equivalent focal length of the first lens group. In some cases, the second lens group is closer to the one or more image sensors than the first lens group, and the convergence power of the second lens group is greater than 25% of the convergence power of the first lens group. In some embodiments, the image sensor has one or more pixel pitches, and the lateral chromatic aberration of the lens system is less than ten times the maximum pixel pitch. In some cases, the lateral chromatic aberration of the lens system is less than (10μm).

[0009] The present disclosure also describes receiving and projecting imaging systems. For example, the imaging system may include one or more image sensors that are configured to capture an image of an object based on light emitted or reflected from the object and passing through a lens system. Similarly, the light projection system may include a light emitting or reflecting device that emits or reflects light into the lens system.

[0010] The present disclosure also describes a method that includes receiving light emitted by or reflected from an object in a lens system. The lens system includes a first lens group, a second lens group, and an aperture stop disposed between the first lens group and the second lens group, wherein each of the first lens group and the second lens group includes at least one respective lens, and wherein at least one of the first lens group or the second lens group includes at least one of a meta-optical element (MOE) lens or a diffractive optical element (DOE) lens. The method further includes capturing an image of the object in one or more image sensors based on light reflected from the object, the light having subsequently passed through the first lens group, the aperture stop, and the second lens group before being irradiated on the one or more image sensors.

[0011] Some embodiments include one or more of the following features. For example, in some embodiments, light emitted or reflected from an object passes through a first lens group before passing through a second lens group, and the total focal length of the first lens group is less than the total focal length of the second lens group. In some embodiments, each of the first lens group and the second lens group includes a respective MOE lens, and light reflected from an object passes through the first MOE lens before passing through the second MOE lens.

[0012] In another aspect, the present disclosure describes a method that includes projecting light emitted or reflected by a light emitting or reflecting device in a lens system. The lens system includes a first lens group, a second lens group, and an aperture stop disposed between the first lens group and the second lens group, wherein each of the first lens group and the second lens group includes at least one respective lens, and wherein at least one of the first lens group or the second lens group includes at least one of a meta-optical element (MOE) lens or a diffractive optical element (DOE) lens.

[0013] Some embodiments include one or more of the following features. For example, in some embodiments, light emitted by or reflected from a light emitting or reflecting device passes through a first lens group before passing through a second lens group, and the equivalent focal length of the first lens group is greater than the equivalent focal length of the second lens group. In some cases, each of the first lens group and the second lens group includes a respective MOE lens, and light emitted or reflected by the light emitting or reflecting device passes through the MOE lens of the first lens group before passing through the MOE lens of the second lens group.

[0014] In some embodiments, the lens systems described in the present disclosure can improve the performance of planar optical lenses by reducing lateral chromatic aberration in an imaging system. Such improvements can help enhance the operating spectral bandwidth of the system and make the system compatible with the bandwidth of standard light sources such as vertical cavity surface emitting lasers (VCSELs) and light emitting diodes (LEDs). In addition to reducing lateral chromatic aberration, in some embodiments, the lens system can correct other types of monochromatic geometric aberrations, such as coma and distortion, thereby further enhancing the overall performance, quality, and / or efficiency of the imaging system. In some cases, the lens arrangement can enhance the field of view (FOV), F number (F / #), and / or compactness (e.g., smaller optical track length) of the imaging system.

[0015] The lens systems described in the present disclosure can be integrated into, for example, MOE- or DOE-based receiver or transmitter optical devices. For example, in some embodiments, MOE-based lens systems can utilize standard design and fabrication methods for nanostructures without sacrificing the very high focusing efficiency (>90%) and diameter size (>1 mm) of the established metaatom library and the design principles of the entire nanostructure in the metasurface. In addition, the lens systems described in the present disclosure can be particularly advantageous for use with relatively high-resolution image sensors, where lateral chromatic aberration may otherwise be a problem. The lens systems described herein can also be incorporated into other types of optical devices (e.g., gratings) and systems.

[0016] Other aspects, features, and advantages will be apparent from the following detailed description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 An example of an imaging system including a lens system is shown.

[0018] Figure 2 Another example of an imaging system including a lens system is shown.

[0019] Figure 3A Examples of chief rays of three different wavelengths passing through an imaging system are shown.

[0020] FIG. 3B to FIG. 3E Shows Figure 3A A magnified version of a section showing the significant reduction in lateral chromatic aberration.

[0021] Figure 4 Still another example of an imaging system including a lens system is shown.

[0022] Figure 5 Further examples of imaging systems including lens systems are shown.

[0023] Figure 6Still another example of an imaging system including a lens system is shown. DETAILED DESCRIPTION

[0024] Since the refractive index of the lens material typically depends at least slightly on the wavelength of the light propagating through the medium, the optical material of the lens usually has a certain degree of wavelength dispersion. This phenomenon is due to the phase velocity of the wave being related to its frequency. An important consequence of dispersion is that the refraction angle varies with the wavelength of the light. Diffraction-based flat optics (such as MOE and DOE) introduce significantly greater dispersion due to the wavelength dependence. These dispersion effects affect the image formation quality and introduce large chromatic aberrations. Chromatic aberrations can be divided into longitudinal (axial) direction or transverse (lateral) direction. Lateral chromatic aberration or lateral color is the lateral or in-plane shift of the principal ray penetrating the image plane due to chromatic aberration in the lens system. It can be defined as the variation of the magnification of the lens system with wavelength. Axial chromatic aberration or axial color is the longitudinal / axial shift of the focus of the marginal rays along the optical axis and can be defined as the variation of the best focus along the optical axis for different wavelengths.

[0025] As described in more detail below, a lens system includes at least two lens groups with an aperture stop disposed therebetween. At least one of the lens groups includes a MOE or DOE lens. Placing the aperture stop between the lens groups can help compensate for lateral chromatic aberration introduced by one or more lenses in the system and balance lateral color shifts. In some cases, by placing the aperture stop between lens groups with similar dispersion characteristics, the system can offset a significant lateral color shift introduced by a lens group disposed before the aperture stop. In some cases, such a system can reduce the variation of lens magnification with wavelength and, therefore, improve the image quality in the tangential direction of the multi-wavelength lens system. In some embodiments, other transverse aberrations such as distortion and coma can also be reduced.

[0026] The systems described herein can be particularly advantageous for arrangements in which the lens groups on both sides of the aperture layer include at least one respective MOE or DOE lens. However, some arrangements include a MOE or DOE lens on only one side of the aperture layer. Either or both of the lens groups can also include other types of lenses (e.g., refractive lenses, gradient index (GRIN) lenses, volume holographic lenses, and / or surface holographic lenses (HOEs), or a combination of different types of lenses).

[0027] like Figure 1As shown in the example of , the lens system 10 includes an aperture stop 16, a first lens group disposed on a first side of the aperture stop 16, and a second lens group disposed on a second side of the aperture stop 16, wherein the second side is opposite to the first side. The first lens group includes at least one first MOE (or DOE) lens 12, and the second lens group includes at least one second MOE (or DOE) lens 14. Each of the first lens group and the second lens group may include one or more additional lenses.

[0028] exist Figure 1 In the example shown, the first MOE (or DOE) lens 12 is disposed before the aperture stop 16 (i.e., closer to the front side 16A of the aperture stop), and the second MOE (or DOE) lens 14 is disposed after the aperture stop 16 (i.e., closer to the rear side 16B of the aperture stop). Thus, for example, if the lens system 10 is integrated into an imaging system 20 (e.g., a camera) that includes a CMOS-based photosensor 22 or other photosensor 22 operable to capture an image of an object 24, the first MOE (or DOE) lens 12 can be closer to the object 24, and the second MOE (or DOE) lens 14 can be closer to the image plane of the sensor 22. In some embodiments, instead of a single image sensor, there may be multiple image sensors (e.g., an image sensor array) that are arranged together to capture an image. Depending on the application, one or more image sensors may be arranged to capture an image of an object based on light emitted by or reflected from the object and passing through the lens system.

[0029] like Figure 1 As shown, for embodiments in which each of the first lens group and the second lens group includes a corresponding MOE lens, the first MOE lens 12 may include a metasurface 30 disposed on an optically translucent or at least partially transparent substrate 32 (e.g., glass, plastic, or polymer material). Similarly, the second MOE lens 14 may include a metasurface 34 disposed on an optically translucent or at least partially transparent substrate 36 (e.g., glass, plastic, or polymer material). The substrates 32, 36 may provide mechanical support for the metasurfaces 30, 34.

[0030] As described above, other optical surfaces with or without refractive light power may also be present in some embodiments to provide additional performance or functionality. In some embodiments, the equivalent lens power of each corresponding lens group (whether composed of a single lens or multiple lenses) on either side of the aperture stop 16 is approximately the same. In some embodiments, the equivalent lens power of the first lens group and the second lens group may be different. For example, in some embodiments, the equivalent lens power of the second lens group (i.e., the lens group closer to the image sensor 22) is stronger than the equivalent lens power of the first lens group (i.e., the one or more lenses closer to the object 24). That is, the group of one or more lenses facing the object 24 has a weaker total power than the group of one or more lenses facing the sensor 22. In some cases, it is advantageous for the equivalent power (or convergence power) of the second lens group facing the image sensor 22 to be greater than 25% of the equivalent power (or convergence power) of the first lens group facing the object 24. Furthermore, in some cases, the equivalent focal power (or focusing power) of the lens group facing image sensor 22 is greater than 50% of the equivalent focal power (or focusing power) of the lens group facing object 24. In some cases, the equivalent focal power (or focusing power) of the lens group facing image sensor 22 is greater than 75% of the equivalent focal power (or focusing power) of the lens group facing object 24.

[0031] On the other hand, in some embodiments (e.g., an optical projection system including a light emitting or reflecting device), the equivalent lens power of the first lens group (i.e., the lens group closer to the light source) can be stronger than the equivalent lens power of the second lens group. The light emitting or reflecting device can be or include, for example, a display, a light engine, a digital micromirror device (DMD), a liquid crystal display (LCD), a liquid crystal on silicon technology (LCOS) projector or other spatial light modulator, a vertical cavity surface emitting laser (VCSEL) chip, or a light emitting diode (LED). In some embodiments, other types of light emitting or reflecting devices can be used.

[0032] The aperture layer can be used as an aperture stop 16 in the system to limit the solid angle of light rays passing through the system from an on-axis object point, thereby defining a cone of light reaching the image plane of the sensor 22. In some embodiments, the aperture layer 16 is composed of a hole (e.g., a circular opening) in a light-blocking material (such as a black chrome layer) disposed on one or both of the substrates 32, 36. In some cases, the first lens 12 and the second lens 14 are securely bonded, stacked, or otherwise attached back to back to each other (i.e., with no gap between them) with the aperture layer 16 disposed therebetween. For example, in some cases, the substrates 32, 36 of the lenses 12, 14 can be securely bonded to each other by an optically clear adhesive. In some embodiments, the aperture stop 16 is physically separated from one (or both) of the lenses 12, 14. That is, as Figure 2 As shown in the example lens system 10A of FIG. 1 , the aperture stop 16 may be separated from the lens substrates 32, 36 by respective air gaps 40A, 40B. In some cases, the air gap 40A (or 40B) exists between the aperture stop 16 and only one of the lens substrates 32 (or 36), and the aperture stop 16 is disposed on the surface of the other of the lens substrates 36 (or 32).

[0033] FIG. 3A to FIG. 3E An example is shown where three main rays of different wavelengths (930nm, 940nm, 950nm) pass through the first metasurface, then through the aperture stop, then through the second metasurface, and finally reach the image plane. The lateral position of the main ray at the second metasurface (see Figure D) is compared with the corresponding lateral position at the first metasurface (see Figure Figure 3B ) on the contrary. Such an arrangement can help to counteract or reduce lateral aberrations, particularly lateral chromatic aberration at the image plane.

[0034] In some embodiments, lateral chromatic aberration can be counteracted or reduced by providing an aperture stop between two lens groups, where at least one lens group includes a MOE or DOE lens. Reduction in lateral chromatic aberration can be particularly advantageous, for example, in imaging systems with a large field of view, such as wide FOV systems. In some cases, the lateral chromatic aberration of the lens system is less than ten times (10x) the radius of the Airy disk of the lens system. In some cases, the lateral chromatic aberration of the lens system is less than two times (2x) the radius of the Airy disk of the lens system. Preferably, the lateral chromatic aberration is reduced to less than the radius of the Airy disk of the lens system (1x). Depending on the specific application, the operating wavelength of the lens system can be, for example, in the visible range (400nm to 700nm), the near infrared range (700nm to 1400nm), the short wavelength infrared range (1.4μm to 3μm), or the mid-infrared wave (3μm to 8μm).

[0035] In some embodiments, the lateral chromatic aberration of the lens system is less than ten times the pixel pitch (10x). In some cases, the lateral chromatic aberration of the lens system is less than five times the pixel pitch (5x). In some cases, the lateral chromatic aberration is reduced to less than the pixel pitch of the image sensor (1x). For embodiments in which each lens system includes a corresponding MOE (or DOE) lens, in some cases, the operating bandwidth of the imaging system can be extended by 5 to 10 times or even higher. The reduction in lateral aberration can be particularly advantageous in MOE- and DOE-based imaging systems, in which chromatic aberrations tend to be relatively large compared to classical volume refractive lenses.

[0036] In some embodiments, the reduction of lateral chromatic aberration can be targeted to a value less than the minimum pixel size of some near-infrared CMOS image sensors (e.g., <1 μm). Thus, in some cases, the operating bandwidth of such a system can be extended beyond the ±10 nm range (i.e., 20 nm full width at half maximum (FWHM)), and even with a ±20 nm bandwidth (i.e., 40 nm FWHM), the modulation transfer function (MTF) or image quality can still be quite high for all field angles. In some embodiments, the lateral chromatic aberration of the lens system is less than 10 μm.

[0037] In some embodiments, it may be desirable to use substrates 32, 36 having specific dimensions. For example, assuming that the substrates 32, 36 are made of glass, and assuming that the thickness of the first substrate 32 is t1, in some cases, the second glass substrate 36 may have a thickness t2 in the range between 0.8×t1 and 2×t1 to provide the desired reduction in lateral color shift at the image plane. In other embodiments, the thickness t2 may be in the range of 0.5×t1 to 3×t1, or in the range of 0.3×t1 to 5×t1. In some embodiments, it may be desirable to use a lens system such that the ratio of the product of the respective focal lengths (f1, f2) before and after the aperture stop 16 and the respective substrate thicknesses (t1, t2) is in the range of 0.5 to 2. That is:

[0038]

[0039] In some embodiments, the aforementioned ratio may fall within the range of 0.3 to 5, or within the range of 0.2 to 10. In some cases, other ranges of the aforementioned values ​​may be suitable.

[0040] In some embodiments, the MOE (or DOE) lens 12 or 14 in the first lens group or the second lens group can be replaced by a curved refractive lens composed of, for example, a bulk glass or plastic material. Figure 4 and Figure 5 An example is shown. Figure 4 In FIG. 1 , lens system 10B includes curved refractive lens 50 instead of a front MOE (or DOE) lens. Figure 5 In the embodiment, the lens system 10C includes a curved refractive lens 50 instead of a rear MOE (or DOE) lens. In some embodiments, the lens group may include other types of lenses (e.g., GRIN lenses, volume holographic lenses, and surface holographic (HOE) lenses or a combination of different types of lenses) instead of or in addition to the refractive lenses 50A, 50B.

[0041] As mentioned above, and as Figure 6As shown in the example lens system 10D of , in some implementations, there may be two or more corresponding lenses on one or both sides of the aperture stop 16. That is, in some cases, the front lens group 60A (i.e., the lens group closer to the front side 16A of the aperture stop) may include multiple lenses, which may be, for example, a combination of planar optics (one or more MOE and / or DOE lenses 12) and one or more other lenses 50A. Similarly, in some cases, the rear lens group 60B (i.e., the lens group closer to the rear side 16B of the aperture stop) may include multiple lenses, which may be, for example, a combination of planar optics (one or more MOE and / or DOE lenses 14) and one or more other lenses 50B, 50C.

[0042] As with the other examples, lens system 10D can be designed to compensate for lateral chromatic aberration introduced by lenses disposed on the object side and to balance lateral chromatic aberration. As an example, if the lens system has two lenses before the aperture stop, the number of lens surfaces or lens elements after the aperture stop is in the range of one to five in some cases. Likewise, if the lens system has three lenses before the aperture stop, the number of lenses after the aperture stop is in the range of two to seven in some cases.

[0043] As described above, lateral chromatic aberration makes the magnification of the system dependent on wavelength. Such wavelength dependence can lead to focal blur and expansion of the point spread function (PSF), which will lead to lower MTF and lower image quality. However, since the overall image quality typically also depends on other types of geometric aberrations, optimizing MTF does not require perfect symmetry of the lens to achieve complete elimination of lateral chromatic aberration. That is, as explained in some of the examples described above, other geometric aberrations should be minimized while solving chromatic aberration, and therefore the architecture of the lens system may not need to be completely symmetrical. For example, one or more lenses facing the object (i.e., before the aperture stop) may have a weaker total focal power than one or more lenses facing the sensor (i.e., after the aperture stop). Therefore, in some cases, the effective focal length of the lens group before the aperture stop (i.e., closer to the object) may be longer than the effective focal length of the lens group after the aperture stop (i.e., closer to the sensor). Compensation for lateral chromatic aberration can still be achieved by appropriately selecting lens parameters and the distance between the lens and the aperture stop.

[0044] Although this specification contains many details, these should not be interpreted as limitations on the scope of the present disclosure or the scope that can be claimed, but as descriptions of features specific to a particular embodiment. Certain features described in this specification in the context of separate embodiments may also be combined in the same embodiment. Conversely, various features described in the context of a single embodiment may also be implemented separately or in any suitable sub-combination in multiple embodiments. Various modifications may be made to the foregoing examples. Therefore, other embodiments are also within the scope of the claims.

Claims

1. A device comprising: A lens system, the lens system comprising: A first lens group; a second lens group; and an aperture stop, the aperture stop being disposed between the first lens group and the second lens group, wherein each of the first lens group and the second lens group includes at least one corresponding lens, and Wherein, at least one of the first lens group or the second lens group includes at least one of a meta-optical element (MOE) lens or a diffractive optical element (DOE) lens.

2. The device according to claim 1, wherein: Each of the first lens group and the second lens group includes at least one of a MOE lens or a DOE lens.

3. The device according to claim 1, wherein: Each of the first lens group and the second lens group includes a respective MOE lens.

4. The device according to claim 3, wherein: Each of the MOE lenses comprises a respective metasurface on a respective substrate, and wherein a respective gap exists between the aperture stop and each of the substrates.

5. The device according to claim 3, wherein: Each of the MOE lenses comprises a respective metasurface on a respective substrate, and wherein there is a gap between the aperture stop and at least one of the substrates.

6. The device according to claim 3, wherein: Each of the MOE lenses comprises a respective metasurface on a respective substrate, and wherein respective back sides of the substrates are attached to each other.

7. The device according to claim 1, wherein: Each of the first lens group and the second lens group includes a respective DOE lens.

8. The device according to any one of claims 1 to 7, wherein: At least one of the first lens group or the second lens group includes a plurality of lenses.

9. The device according to any one of claims 1 to 8, wherein: The total focal power of the first lens group is different from the total focal power of the second lens group.

10. The device according to any one of claims 1 to 8, wherein: The total focal power of the first lens group is the same as the total focal power of the second lens group.

11. The device according to any one of claims 1 to 10, wherein: The lateral chromatic aberration of the lens system is less than ten times the radius of the Airy disk of the lens system.

12. The apparatus according to any one of claims 1 to 11, further comprising one or more image sensors configured to capture an image of the object based on light emitted by or reflected from the object and passing through the lens system.

13. The device according to claim 12, wherein: The second lens group is closer to the one or more image sensors than the first lens group, and wherein an equivalent focal power of the second lens group is greater than 25% of an equivalent focal power of the first lens group.

14. The device according to claim 12, wherein: The second lens group is closer to the one or more image sensors than the first lens group, and wherein a focusing power of the second lens group is greater than 25% of a focusing power of the first lens group.

15. The apparatus according to any one of claims 1 to 11, further comprising an image sensor arranged to capture an image of the object based on light emitted by or reflected from the object and passing through the lens system, wherein The image sensor has one or more pixel pitches, and wherein the lateral chromatic aberration of the lens system is less than ten times the maximum pixel pitch.

16. The device according to any one of claims 1 to 15, wherein: The lateral chromatic aberration of the lens system is less than 10 μm.

17. A method comprising: receiving light emitted by or reflected from an object in a lens system, wherein the lens system includes a first lens group, a second lens group, and an aperture stop disposed between the first lens group and the second lens group, wherein each of the first lens group and the second lens group includes at least one respective lens, and wherein at least one of the first lens group or the second lens group includes at least one of a meta-optical element (MOE) lens or a diffractive optical element (DOE) lens; and An image of the object is captured in an image sensor based on light emitted by or reflected from the object, the light having subsequently passed through the first lens group, the aperture stop, and the second lens group before impinging on the image sensor.

18. The method according to claim 17, wherein: Light emitted by or reflected from the object passes through the first lens group before passing through the second lens group, and wherein an equivalent focal power of the first lens group is smaller than an equivalent focal power of the second lens group.

19. The method according to any one of claims 17 to 18, wherein: The lateral chromatic aberration of the lens system is less than ten times the radius of the Airy disk of the lens system.

20. The method according to any one of claims 17 to 18, wherein: The image sensor has one or more pixel pitches, and wherein the lateral chromatic aberration of the lens system is less than ten times the maximum pixel pitch.

21. The method according to any one of claims 17 to 20, wherein: The lateral chromatic aberration of the lens system is less than 10 μm.

22. The method according to any one of claims 17 to 21, wherein: Each of the first lens group and the second lens group includes a respective MOE lens, and wherein light emitted by or reflected from the object passes through the MOE lens of the first lens group before passing through the MOE lens of the second lens group.

23. A method comprising: Light emitted by or reflected from a light emitting or reflecting device is projected in a lens system, wherein the lens system includes a first lens group, a second lens group, and an aperture stop disposed between the first lens group and the second lens group, wherein each of the first lens group and the second lens group includes at least one corresponding lens, and wherein at least one of the first lens group or the second lens group includes at least one of a meta-optical element (MOE) lens or a diffractive optical element (DOE) lens.

24. The method according to claim 23, wherein: Light emitted by or reflected from the light emitting or reflecting device passes through the first lens group before passing through the second lens group, and wherein the equivalent focal power of the first lens group is greater than the equivalent focal power of the second lens group.

25. The method according to any one of claims 23 to 24, wherein: Each of the first lens group and the second lens group includes a respective MOE lens, and wherein light emitted by or reflected from the light emitting or reflecting device passes through the MOE lens of the first lens group before passing through the MOE lens of the second lens group.

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