Optical lens system and imaging system incorporating the optical lens system

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 meta-optical element (MOE) lens or a diffractive optical element (DOE) lens. The present disclosure also describes receiving and projecting imaging systems including the lens system, and related methods.

Description

[Technical Field]

[0001] Field of Disclosure The present disclosure relates to optical lens systems and imaging systems incorporating optical lens systems. [Background technology]

[0002] background Some lenses, such as meta-optical elements (MOEs) and diffractive optical elements (DOEs), employ flat optics technology. MOEs, for example, have metasurfaces containing dispersed small subwavelength structures (e.g., nanostructures or other meta-atoms) arranged to interact with light in specific ways. The meta-atoms can individually and / or collectively interact with light waves to alter the local amplitude, local phase, or both of the incident light wave. Similarly, DOEs have microstructure patterns that alter and control the phase of the incident light wave. By modifying the microstructure, DOEs are capable of generating a range of beam intensity profiles or beam shapes. MOEs or DOEs can be used in optical applications to take advantage of their flat surfaces and reduced thickness compared to classical curved refractive lenses, for example.

[0003] However, flat optical lenses such as MOEs and DOEs tend to suffer from significant chromatic dispersion due to the strong wavelength dependence of diffraction phenomena. If such chromatic dispersion is not addressed, imaging systems incorporating such optical elements may have significant chromatic aberrations, resulting in a more limited (i.e., narrow) operating spectral bandwidth (e.g., only a few nanometers). Such constraints can impose severe restrictions on the choice of light source for scene illumination and can limit the overall efficiency of these imaging systems. Summary of the Invention [Means for solving the problem]

[0004] overview SUMMARY This disclosure describes optical lens systems and imaging systems incorporating optical lens systems, as well as related methods.

[0005] For example, in one aspect, the present disclosure describes an apparatus including a lens system including a first group of lenses, a second group of lenses, and an aperture stop disposed between the first group of lenses and the second group of lenses, wherein the first group of lenses and the second group of lenses each include at least one respective lens, and at least one of the first group of lenses or the second group of lenses 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 an MOE lens or a DOE lens. In some embodiments, each of the first lens group and the second lens group includes a respective MOE lens. In some cases, each of the MOE lenses includes a respective metasurface on a respective substrate, with a respective gap between the aperture stop and each of the substrates. In some cases, each of the MOE lenses includes a respective metasurface on a respective substrate, with a gap between the aperture stop and at least one of the substrates. In some cases, each of the MOE lenses includes a respective metasurface on a respective substrate, with a respective back surface of each of the substrates attached to another. In some embodiments, each of the first lens group and the second lens group includes a respective DOE lens.

[0007] In some embodiments, at least one of the first lens group or the second lens group includes multiple lenses. The total power of the first lens group may be the same as or different from the total power of the second lens group, depending on the application. Furthermore, in some cases, for example, the lateral chromatic aberration of the lens system is less than 10 times the Airy disk radius of the lens system.

[0008] In some embodiments, the device further includes one or more image sensors positioned to capture an image of the object based on light emitted or reflected by 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 power of the second lens group is greater than 25% of the equivalent power 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 focusing power of the second lens group is greater than 25% of the focusing power of the first lens group. In some embodiments, the image sensor has a pixel pitch of one or more, and the lateral chromatic aberration of the lens system is less than 10 times the maximum pixel pitch. In some cases, the lateral chromatic aberration of the lens system is less than 10 μm.

[0009] This disclosure also describes optical receiving and projection imaging systems. For example, an imaging system can include one or more image sensors positioned to capture an image of an object based on light emitted or reflected by the object and passing through a lens system. Similarly, an optical projection system can 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 or reflected by an object at 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 including at least one respective lens, and at least one of the first lens group or the second lens group including 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 at one or more image sensors based on the light reflected by the object, the light subsequently passing through the first lens group, the aperture stop, and the second lens group before impinging 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 by the object passes through a first lens group before passing through a second lens group, and the total power of the first lens group is less than the total power of the second lens group. In some embodiments, the first lens group and the second lens group each include a respective MOE lens, and light reflected by the object passes through the first MOE lens before passing through the second MOE lens.

[0012] In a further aspect, the present disclosure describes a method that includes projecting light emitted or reflected by a light emitting or reflecting device at a lens system that 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 including at least one respective lens, and at least one of the first lens group or the second lens group including 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 or reflected by the light emitting or reflecting device passes through a first lens group before passing through a second lens group, and the equivalent power of the first lens group is greater than the equivalent power of the second lens group. In some cases, the first lens group and the second lens group each include 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 herein can improve the performance of flat optical lenses by reducing lateral chromatic aberration in imaging systems. Such improvements can increase the system's operating spectral bandwidth, helping it match 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 systems can correct other types of monochromatic geometric aberrations, such as coma and distortion, thereby further improving the overall performance, quality, and / or efficiency of the imaging system. In some cases, the lens arrangement can improve the field of view (FOV), F-number (F / #), and / or compactness (e.g., shorter optical track length) of the imaging system.

[0015] The lens systems described herein can be integrated into, for example, MOE- or DOE-based receiving or transmitting optical elements. In some embodiments, MOE-based lens systems can utilize standard nanostructure design and fabrication methods without sacrificing the extremely high focusing efficiency (>90%) and diameter size (>1 mm) of the established library of meta-atoms and the overall nanostructure design principles of metasurfaces. Furthermore, the lens systems described herein can be particularly advantageous for use with relatively high-resolution image sensors, where lateral chromatic aberrations can otherwise be problematic. The lens systems described herein can also be incorporated into other types of optical devices (e.g., diffraction gratings) and systems.

[0016] Other aspects, features, and advantages will become readily apparent from the following detailed description, the accompanying drawings, and the claims. [Brief explanation of the drawings]

[0017] [Figure 1] 1 illustrates an example of an imaging system including a lens system. [Figure 2]1 illustrates another example of an imaging system including a lens system. [Figure 3A] 1 shows an example of chief rays at three different wavelengths passing through an imaging system. [Figure 3B] 3B shows an enlarged version of a portion of FIG. 3A, illustrating the significant reduction in lateral chromatic aberration. [Figure 3C] 3B shows an enlarged version of a portion of FIG. 3A, illustrating the significant reduction in lateral chromatic aberration. [Figure 3D] 3B shows an enlarged version of a portion of FIG. 3A, illustrating the significant reduction in lateral chromatic aberration. [Figure 3E] 3B shows an enlarged version of a portion of FIG. 3A, illustrating the significant reduction in lateral chromatic aberration. [Figure 4] 1 illustrates yet another example of an imaging system including a lens system. [Figure 5] 1 illustrates a further example of an imaging system including a lens system. [Figure 6] 1 illustrates yet another example of an imaging system including a lens system. DETAILED DESCRIPTION OF THE INVENTION

[0018] Detailed Description Because the refractive index of a lens material typically depends at least slightly on the wavelength of light propagating through the medium, lens optical materials generally have some degree of wavelength dispersion. This phenomenon is due to the dependence of the wave's phase velocity on its frequency. An important consequence of dispersion is the change in the refraction angle as a function of light wavelength. Diffraction-based flat optical elements, such as MOEs and DOEs, exhibit significantly greater dispersion due to wavelength dependence. These dispersion effects affect image formation quality and result in significant chromatic aberration. Chromatic aberration can be divided into longitudinal (axial) and transverse (horizontal) directions. Transverse chromatic aberration, or transverse color, is the lateral or transverse in-plane shift of the chief ray penetrating the image plane due to chromatic aberration in a lens system. It can be defined as the change in the lens system magnification factor with wavelength.

[0019] Axial chromatic aberration or axial color is the longitudinal / axial shift in the marginal ray focus along the optical axis and can be defined as the change in best focus along the optical axis for different wavelengths.

[0020] As described in more detail below, the lens system includes at least two lens groups with an aperture stop disposed between them. At least one of the lens groups includes an MOE or DOE lens. Placing an aperture stop between the lens groups can help correct lateral chromatic aberrations and balance lateral color shifts introduced by one or more lenses in the system. In some cases, by placing an aperture stop between lens groups with similar dispersion characteristics, the system can offset the significant lateral color shifts introduced by the lens group placed before the aperture stop. Such a system can, in some cases, reduce the variation in lens magnification with wavelength, thus improving the tangential image quality of the multi-wavelength lens system. In some embodiments, other lateral aberrations, such as distortion and coma, can be reduced as well.

[0021] 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. Nevertheless, some arrangements include an MOE or DOE lens on only one side of the aperture layer. One or both of the lens groups can also include other types of lenses (e.g., refractive lenses, gradient index (GRIN) lenses, volume lenses, and / or surface holographic lenses (HOEs)), or a combination of different types of lenses.

[0022] 1, lens system 10 includes an aperture stop 16, a first lens group disposed on a first side of aperture stop 16, and a second lens group disposed on a second side of aperture stop 16, the second side being opposite 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.

[0023] In the example shown in FIG. 1 , the first MOE (or DOE) lens 12 is positioned in front of the aperture stop 16 (i.e., closer to the front surface 16A of the aperture stop), and the second MOE (or DOE) lens 14 is positioned after the aperture stop 16 (i.e., closer to the back surface 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 or other optoelectronic sensor 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 can be multiple image sensors (e.g., an array of image sensors) collectively arranged to capture an image. Depending on the application, one or more image sensors can be positioned to capture an image of the object based on light emitted or reflected by the object and passing through the lens system.

[0024] 1 , in embodiments in which the first and second lens groups each include a respective MOE lens, the first MOE lens 12 can 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 can 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 can provide mechanical support for the metasurfaces 30, 34.

[0025] As noted above, other optical surfaces, with or without refractive optical power, may be present in some embodiments to provide additional performance or functionality. In some embodiments, the equivalent lens power of each respective lens group (whether consisting of a single lens or multiple lenses) on either side of 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 image sensor 22) is stronger than the equivalent lens power of the first lens group (i.e., the lens closer to object 24). That is, the group of one or more lenses facing object 24 may have a weaker total power than the group of one or more lenses facing sensor 22. In some cases, it is advantageous for the equivalent power (or focusing power) of the second lens group facing image sensor 22 to be greater than 25% of the equivalent power (or focusing power) of the first lens group facing object 24. Furthermore, in some cases, the equivalent power (or focusing power) of the lens group facing image sensor 22 is greater than 50% of the equivalent power (or focusing power) of the lens group facing object 24. In some cases, the equivalent power (or focusing power) of the lens group facing image sensor 22 is greater than 75% of the equivalent power (or focusing power) of the lens group facing object 24.

[0026] On the other hand, in some embodiments (e.g., optical projection systems including light-emitting or reflective devices), the equivalent lens power of the first lens group (i.e., the lens group closer to the light source) may be stronger than the equivalent lens power of the second lens group. The light-emitting or reflective device may 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 (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 reflective devices may be used.

[0027] The aperture layer can function 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, which defines the cone of light reaching the image plane of the sensor 22. In some embodiments, the aperture layer 16 is comprised of holes (e.g., circular openings) 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 and second lenses 12, 14 are glued, laminated, or otherwise attached to one another back-to-back (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 glued together with 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 shown in the example lens system 10A of FIG. 2, the aperture stop 16 can 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), with the aperture stop 16 being located on the other surface of the lens substrate 36 (or 32).

[0028] Figures 3A-3E show an example of chief rays at three different wavelengths (930 nm, 940 nm, and 950 nm) passing through a first metasurface, then through an aperture stop, then through a second metasurface, and finally to the image plane. The lateral positions of the chief rays at the second metasurface (see Figure D) are opposite to their respective lateral positions at the first metasurface (see Figure 3B). Such an arrangement can help cancel or reduce lateral aberrations at the image plane, specifically lateral chromatic aberrations.

[0029] In some embodiments, lateral chromatic aberration can be canceled or reduced by providing an aperture stop between two lens groups, at least one of which includes an MOE or DOE lens. Reducing lateral chromatic aberration can be particularly advantageous in imaging systems with large field of view, such as wide FOV systems. In some cases, the lateral chromatic aberration of the lens system is less than 10 times (10x) the Airy disk radius of the lens system. In some cases, the lateral chromatic aberration of the lens system is less than twice (2x) the Airy disk radius of the lens system. Preferably, the lateral chromatic aberration is reduced to less than the Airy disk radius of the lens system (1x). Depending on the particular application, the operating wavelength of the lens system may be, for example, the visible range (400 nm to 700 nm), the near-infrared range (700 nm to 1400 nm), the short-wavelength infrared range (1.4 um to 3 um), or the mid-wavelength infrared range (3 um to 8 um).

[0030] In some embodiments, the lateral chromatic aberration of the lens system is less than 10 times (10x) the pixel pitch. In some cases, the lateral chromatic aberration of the lens system is less than 5 times (5x) the pixel pitch. In some cases, the lateral chromatic aberration is reduced to less than the pixel pitch (1x) of the image sensor. In embodiments in which each of the lens systems includes a respective MOE (or DOE) lens, the operating bandwidth of the imaging system can be expanded by 5x to 10x, or even more, in some cases. Reducing lateral aberrations can be particularly advantageous in MOE- and DOE-based imaging systems, which tend to have relatively large chromatic aberrations compared to classical bulk refractive lenses.

[0031] In some embodiments, the reduction of lateral chromatic aberration can be targeted to values ​​smaller than the minimum pixel size of some near-infrared CMOS image sensors (e.g., <1 μm). As a result, the operating bandwidth of such systems can in some cases extend beyond a ±10 nm range (i.e., 20 nm full width half maximum (FWHM)), and the modulation transfer function (MTF), or image quality, can still be very high for all angles of view even when a ±20 nm bandwidth is used (i.e., 40 nm FWHM). In some embodiments, the lateral chromatic aberration of the lens system is less than 10 μm.

[0032] In some embodiments, it may be desirable to use substrates 32, 36 having specific dimensions. For example, assuming that substrates 32, 36 are constructed from glass and that the first substrate 32 has a thickness t1, the second glass substrate 36 may have a thickness t2 in the range of 0.8×t1 to 2×t1 to provide the desired reduction in lateral color shift at the image plane. In other embodiments, 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 in which the ratio of the product of the respective focal lengths (f1, f2) before and after the aperture 16 and the respective substrate thicknesses (t1, t2) is in the range of 0.5 to 2. That is,

[0033]

number

[0034] is. In some embodiments, the aforementioned ratio may be in the range of 0.3 to 5, or in the range of 0.2 to 10. In some cases, other ranges of the aforementioned values ​​may be appropriate.

[0035] In some embodiments, the MOE (or DOE) lens 12 or 14 in the first or second lens group can be replaced with a curved refractive lens, for example, constructed from bulk glass or plastic material. Examples are shown in FIGS. 4 and 5. In FIG. 4, lens system 10B includes a curved refractive lens 50 in place of the front MOE (or DOE) lens. In FIG. 5, lens system 10C includes a curved refractive lens 50 in place of the back MOE (or DOE) lens. In some embodiments, the lens groups can include other types of lenses (e.g., GRIN lenses, volume and surface holographic (HOE) lenses, or combinations of different types of lenses) instead of or in addition to the refractive lenses 50A, 50B.

[0036] As discussed above and shown in the example lens system 10D of FIG. 6, in some embodiments, there may be two or more respective 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 surface 16A of the aperture stop) may include multiple lenses, which may be, for example, a combination of a flat optical element (one or more MOE and / or DOE lenses 12) and one or more other lenses 50A. Similarly, in some cases, the back lens group 60B (i.e., the lens group closer to the back surface 16B of the aperture stop) may include multiple lenses, which may be, for example, a combination of a flat optical element (one or more MOE and / or DOE lenses 14) and one or more other lenses 50B, 50C.

[0037] As with other examples, lens system 10D can be designed to compensate for and balance lateral chromatic focal shifts introduced by object-side lenses. As an example, if a lens system has two lenses before the aperture stop, the number of lens surfaces or lens elements after the aperture stop may range from 1 to 5. Similarly, in some cases, if a lens system has three lenses before the aperture stop, the number of lenses after the aperture stop may range from 2 to 7.

[0038] As noted above, lateral chromatic aberrations cause the system's magnification to depend on wavelength. Such wavelength dependence can result in defocus and broadening of the point spread function (PSF), resulting in reduced MTF and reduced image quality. However, because overall image quality typically also depends on other types of geometric aberrations, optimizing MTF does not require perfect lens symmetry to achieve complete cancellation of lateral chromatic aberrations. That is, as shown in some of the examples above, other geometric aberrations should also be minimized while chromatic aberrations are addressed, and therefore the lens system structure may not need to be perfectly symmetrical. For example, one or more lenses facing the object (i.e., before the aperture stop) may have weaker total 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) can be longer than the effective focal length of the lens group after the aperture stop (i.e., closer to the sensor). Correction of lateral chromatic aberrations can still be achieved by appropriately selecting the lens parameters and the distance between the lens and the aperture stop.

[0039] While this specification contains many details, these should not be construed as limitations on the scope of the disclosure or what may be claimed, but rather as descriptions of features specific to particular embodiments. Certain features described herein 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 in multiple embodiments separately or in any suitable subcombination. Various modifications can be made to the foregoing examples. Accordingly, other embodiments are within the scope of the claims.

Claims

1. a first lens group; and a second lens group; and an aperture stop disposed between the first lens group and the second lens group; Lens system including Equipped with each of the first and second lens groups includes at least one respective lens; 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 apparatus of claim 1 , wherein each of the first and second lens groups includes at least one of an MOE lens or a DOE lens.

3. The apparatus of claim 1 , wherein the first lens group and the second lens group each include a respective MOE lens.

4. 4. The apparatus of claim 3, wherein each of the MOE lenses includes a respective metasurface on a respective substrate, and there is a respective gap between the aperture stop and each of the substrates.

5. 4. The apparatus of claim 3, wherein each of the MOE lenses includes 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. 4. The apparatus of claim 3, wherein each of the MOE lenses comprises a respective metasurface on a respective substrate, the back surface of each of the substrates being attached to another.

7. The apparatus of claim 1 , wherein the first lens group and the second lens group each include a respective DOE lens.

8. The apparatus of any one of claims 1 to 7, wherein at least one of the first lens group or the second lens group comprises a plurality of lenses.

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

10. 9. The apparatus of claim 1, wherein the total power of the first lens group is the same as the total power of the second lens group.

11. An apparatus according to any preceding claim, wherein the lateral chromatic aberration of the lens system is less than 10 times the Airy disk radius of the lens system.

12. 12. The apparatus of claim 1, further comprising one or more image sensors arranged to capture images of an object based on light emitted by or reflected from the object and passing through the lens system.

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

14. 13. The apparatus of claim 12, wherein the second lens group is closer to the one or more image sensors than the first lens group, and the light-gathering power of the second lens group is greater than 25% of the light-gathering power of the first lens group.

15. 12. The apparatus of claim 1, further comprising an image sensor arranged to capture an image of an object based on light emitted by or reflected from the object and passing through the lens system, the image sensor having one or more pixel pitches, and wherein the lateral chromatic aberration of the lens system is less than 10 times the maximum pixel pitch.

16. 16. Apparatus according to any one of the preceding claims, wherein the lens system has a lateral chromatic aberration of less than 10 μm.

17. receiving light emitted or reflected by an object in a lens system, the lens system including 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 including at least one respective lens, and at least one of the first lens group or the second lens group including at least one of a meta-optical element (MOE) lens or a diffractive optical element (DOE) lens; capturing an image of the object at an image sensor based on the light emitted or reflected by the object, the light passing sequentially through the first lens group, the aperture stop, and the second lens group before impinging on the image sensor; A method comprising:

18. 18. The method of claim 17, wherein the light emitted or reflected by the object passes through the first lens group before passing through the second lens group, and the equivalent power of the first lens group is less than the equivalent power of the second lens group.

19. The method of any one of claims 17 to 18, wherein the lateral chromatic aberration of the lens system is less than 10 times the Airy disk radius of the lens system.

20. The method of any one of claims 17 to 18, wherein the image sensor has one or more pixel pitches, and the lateral chromatic aberration of the lens system is less than 10 times the maximum pixel pitch.

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

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

23. Projecting light emitted or reflected by a light-emitting or reflecting device in a lens system, the lens system including 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 including at least one respective lens, and at least one of the first lens group or the second lens group including at least one of a meta-optical element (MOE) lens or a diffractive optical element (DOE) lens. A method comprising:

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

25. 25. The method of claim 23, wherein each of the first lens group and the second lens group includes a respective MOE lens, and the 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.

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