Telecentric optical lenses and spectral cameras that include the same optical lenses

Abstract

This invention relates to an image-side telecentric optical lens (100) that can be used efficiently in a spectral camera of a mobile user device. The optical lens (100) includes a first lens group (102) and a second lens group (104), wherein the first lens group (102) and the second lens group (104) are arranged sequentially along the optical axis (106) of the optical lens (100). The first lens group (102) includes at least one aspherical lens element. The second lens group (104) includes a first aspherical lens element (104-1), a second aspherical lens element (104-2), and a third aspherical lens element (104-3). The first aspherical lens element (104-1) and the second aspherical lens element (104-2) of the second lens group (104) are used to correct chromatic aberration of the optical lens (100). The third aspherical lens element (104-3) of the second lens group (104) is used to refract the principal ray that is substantially parallel to the optical axis of the optical lens (100). The total optical power of the first lens group (102) is higher than the total optical power of the second lens group (104). Preferred parameter values ​​for each aspherical lens element in the optical lens (100) are also given.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to International Patent Application No. PCT / CN2022 / 098463, filed on June 13, 2022, entitled “Spectral Camera Lenses”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention generally relates to the field of spectroscopic cameras. Specifically, this invention relates to an optical lens having an image-side telecentric design, and a spectroscopic camera including the optical lens. Background Technology

[0004] The advantages of sensor technology and the emergence of new user applications have spurred demand for spectral or hyperspectral cameras built into mobile user devices, such as mobile phones. Although mobile applications for spectral cameras have not yet been developed, possible examples may include, but are not limited to, material identification and classification, food ripeness and condition, skin color recognition, and light source recognition.

[0005] For integration into mobile phones, the spectroscopic camera should be as small as possible. At the same time, the length of the spectroscopic camera along its optical axis is also a significant limiting factor. On the other hand, the spectroscopic camera ideally has a large field of view (FOV) and a large image sensor.

[0006] Image sensors typically employ different band selection methods. For example, band selection can be achieved using absorptive filters or interference-based filters. The latter is commonly represented by thin-film filters and Fabry-Perot filters. The advantage of interference-based filters lies in their mature design and manufacturing, and they generally offer a wider transmission band compared to absorptive filters. However, an inherent problem with interference-based filters is that the passband (or suppression band) position (in wavelength space) shifts with the angle of incidence. This problem is particularly pronounced within a large field of view (FOV). It is well known that as the angle of incidence increases from normal incidence, the transmission band of an interference-based filter shifts to shorter wavelengths. To address this issue, the use of image-side telecentric lenses in spectrophotometers has been proposed, which can achieve a principal ray angle close to 0° across the entire image area.

[0007] However, for image-side telecentric lenses to be used efficiently in the spectroscopic cameras of mobile user devices, they must at least meet the following performance requirements: small size; large field of view (FOV) and no band shift at large FOV angles (i.e., at the edges of the image); large depth of focus without the need for autofocus; and a wavelength range greater than that of traditional mobile phone cameras (e.g., for certain ultraviolet (UV) and / or infrared (IR) applications). These requirements make lens design more challenging. Summary of the Invention

[0008] This invention is intended to provide a brief overview of some concepts, which will be further described in specific embodiments. This invention is neither intended to identify key features nor to limit the scope of the invention.

[0009] The purpose of this invention is to provide an image-side telecentric optical lens that can be used efficiently in the spectral camera of a mobile user device (e.g., a mobile phone).

[0010] The above-mentioned objectives are achieved by the features of the independent claims in the appended claims. Other embodiments and examples will be apparent from the dependent claims, detailed descriptions, and drawings.

[0011] In a first aspect, an optical lens is provided. The optical lens includes a first lens group and a second lens group. The first lens group is arranged along the optical axis of the optical lens and includes at least one aspherical lens element. The second lens group is arranged after the first lens group along the optical axis of the optical lens. The second lens group includes a first aspherical lens element, a second aspherical lens element, and a third aspherical lens element arranged sequentially along the optical axis of the optical lens. The first and second aspherical lens elements are used to correct chromatic aberration of the optical lens. The third aspherical lens element is used to refract a principal ray substantially parallel to the optical axis of the optical lens. The total optical power of the first lens group is higher than the total optical power of the second lens group. The negative focal length of the first aspherical lens element is -1.2 mm to -0.8 mm, the refractive index is 1.60 to 1.75, and the Abbe number is 17 to 25. The positive focal length of the second aspherical lens element is 2.1 mm to 2.5 mm, the refractive index is 1.50 to 1.60, and the Abbe number is 50 to 60. The third aspherical lens element has a positive focal length of 3.8 mm to 4.4 mm, a refractive index of 1.60 to 1.75, and an Abbe number of 15 to 30. This optical lens configuration is image-side telecentric and suitable for use in spectroscopic cameras to be integrated into mobile user equipment (e.g., mobile phones).

[0012] In an exemplary embodiment of the first aspect, the first lens group and the second lens group are configured to operate in the light wavelength range of 400 nm to 850 nm. This may enable the optical lenses to be suitable for mobile applications involving near-UV light, visible light, and near-IR light.

[0013] In an exemplary embodiment of the first aspect, the first lens group and the second lens group are configured such that the effective focal length of the optical lens is less than or equal to 2.3 mm. An optical lens with this effective focal length can be used more efficiently in a spectral camera of a mobile user device.

[0014] In an exemplary embodiment of the first aspect, the first lens group and the second lens group are configured such that the diagonal field of view of the optical lens is –40° to +40°. If an optical lens with a diagonal FOV of 80° is used in a spectrophotometer, the area that the spectrophotometer can image (i.e., the FOV) becomes much larger, thereby enabling the capture of more efficient images containing more data / details, and the capture of fewer images to capture the entire object of interest.

[0015] In an exemplary embodiment of the first aspect, the first lens group and the second lens group are configured such that the ratio of the total trajectory length to the full image diagonal is less than or equal to 1.3. Such an optical lens configuration achieves an optimal trade-off between the size of the optical lens and the height of the image to be captured using the optical lens in the spectral camera.

[0016] In an exemplary embodiment of the first aspect, the at least one aspherical lens element of the first lens group includes a first aspherical lens element with a positive focal length of 3 mm to 4 mm, a second aspherical lens element with a positive focal length of 5 mm to 10 mm, and a third aspherical lens element with a positive focal length of 5 mm to 10 mm. This configuration of the first lens group can additionally correct chromatic aberration of the optical lens and efficiently correct other types of aberrations that may exist in the optical lens (e.g., spherical aberration, coma, astigmatism, field curvature aberration, distortion aberration, etc.).

[0017] In an exemplary embodiment of the first aspect, the optical lens further includes an aperture stop, wherein the aperture stop is located between the second aspherical lens element and the third aspherical lens element in the first lens group. When the aperture stop is in this position, the optical lens can operate more efficiently in a spectral camera of a mobile user device.

[0018] In an exemplary embodiment of the first aspect, the first lens group and the second lens group are configured such that the f-number of the optical lens is greater than or equal to 2.8. An optical lens with this f-number can be used more efficiently in a spectral camera of a mobile user device.

[0019] In a second aspect, a spectroscopic camera is provided, comprising the optical lens and image sensor described in the first aspect. The image sensor is arranged behind the optical lens along the optical axis. Such a spectroscopic camera can be used efficiently in mobile user equipment (e.g., mobile phones).

[0020] In an exemplary embodiment of the second aspect, the spectroscopic camera further includes a spectral filter disposed between the optical lens and the image sensor. The spectral filter can provide the desired spectral response (or in other words, band selection).

[0021] In an exemplary embodiment of the second aspect, in addition to the spectral filter between the optical lens and the image sensor, the spectral camera further includes a spectral filter disposed directly on the image sensor. Such a combination of spectral filters can provide different desired spectral responses.

[0022] In one exemplary embodiment of the second aspect, the spectral filter disposed between the optical lens and the image sensor includes at least one color filter (e.g., an absorption filter, an interference-based filter, a metasurface color filter, a quantum dot color filter, or any combination thereof). These types of spectral filters can provide more efficient band selection.

[0023] In an exemplary embodiment of the second aspect, each of the spectral filters disposed between the optical lens and the image sensor, and the spectral filters disposed directly on the image sensor, includes at least one color filter (e.g., an absorption filter, an interference-based filter, a metasurface color filter, a quantum dot color filter, or any combination thereof). These types of spectral filters can provide more efficient band selection.

[0024] Other features and advantages of the invention will become apparent after reading the following detailed description and reviewing the accompanying drawings. Attached Figure Description

[0025] The invention will now be described with reference to the accompanying drawings, in which:

[0026] Figure 1 A schematic block diagram of an optical lens according to an exemplary embodiment is shown;

[0027] Figure 2 An exemplary embodiment is shown, including Figure 1 A schematic block diagram of a spectral camera with optical lenses;

[0028] Figure 3It shows Figure 2 In the spectral camera Figure 1 How do optical lenses refract light?

[0029] Figure 4A and Figure 4B It shows Figure 1 The dependence of field curvature (in millimeters) and F-Tan (Theta) distortion (in percentage) of optical lenses on the object field angle at different light wavelengths;

[0030] Figure 5 It shows Figure 1 The dependence of the modulus of the optical transfer function (OTF) of an optical lens on the spatial frequency (in periods / mm) at different image field heights (in mm). Detailed Implementation

[0031] The various embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. However, the invention may be embodied in many other forms and should not be construed as limited to any particular structure or function discussed in the following description. Rather, these embodiments are provided to make the description of the invention more detailed and complete.

[0032] As will be apparent to those skilled in the art from the specific embodiments described herein, the scope of this invention includes any of the embodiments disclosed herein, whether implemented independently or in conjunction with any other embodiments of the invention. For example, in practice, the apparatus disclosed herein can be implemented using any number of the embodiments provided herein. Furthermore, it should be understood that any embodiment of the invention can be implemented using one or more elements or steps provided in the appended claims.

[0033] As used herein, the term "exemplary" means "for illustration." Unless otherwise stated, any embodiment described herein as "exemplary" should not be construed as a preferred embodiment or as having an advantage over other embodiments.

[0034] To facilitate the description of the relationship between one element or feature and one or more other elements or features according to the accompanying drawings, any positioning terms such as "left," "right," "top," "bottom," "upper," "lower," "above," "below," "horizontal," "vertical," etc., may be used herein. It should be understood that positioning terms are intended to include different orientations of the device disclosed herein other than those described in the figures. For example, if the device in the figures is envisioned to be rotated 90 degrees clockwise, the element or feature described as "left" and "right" relative to other elements or features would be located "above" and "below" of the other elements or features, respectively. Therefore, the positioning terms used herein should not be construed as any limitation on the invention.

[0035] Although the terms “first,” “second,” and other similar designations may be used herein to describe various embodiments, elements, or features, these embodiments, elements, or features should not be limited by such designations. The designations used herein are intended only to distinguish one embodiment, element, or feature from another. Therefore, without departing from the teachings of the invention, the first lens group discussed below may be referred to as the second lens group, and vice versa.

[0036] According to the exemplary embodiments disclosed herein, a mobile user equipment (MUE) can refer to a mobile station, mobile terminal, mobile user unit, mobile phone, cellular phone, smartphone, cordless phone, personal digital assistant (PDA), wireless communication device, laptop computer, tablet computer, gaming device, netbook, smartbook, ultrabook, medical mobile device, biometric sensor, wearable device (e.g., smartwatch, smart glasses, smart wristband, etc.), entertainment device (e.g., audio player, video player, etc.), smart meter / sensor, unmanned aerial vehicle (UAV) (e.g., industrial robot, quadcopter, etc.), industrial manufacturing equipment, global positioning system (GPS) device, Internet of Things (IoT) device, Industrial Internet of Things (IIoT) device, machine-type communication (MTC) device, a group of Massive Internet of Things (MIoT) or Massive Machine-Type Communication (mMTC) devices / sensors, or any other suitable mobile device that a user can carry with them. In some embodiments, a MUE can refer to at least two juxtaposed and interconnected mobile devices as defined herein.

[0037] The exemplary embodiments disclosed herein relate to an image-side telecentric optical lens, which can be used efficiently in a spectroscopic camera of a mobile user device. More specifically, the optical lens includes a first lens group and a second lens group. The first lens group is arranged along the optical axis of the optical lens and includes at least one aspherical lens element. The second lens group is arranged after the first lens group along the optical axis of the optical lens. The second lens group includes a first aspherical lens element, a second aspherical lens element, and a third aspherical lens element arranged sequentially along the optical axis of the optical lens. The first and second aspherical lens elements of the second lens group are primarily used to correct chromatic aberration of the optical lens. The third aspherical lens element of the second lens group is used to refract the principal ray substantially parallel to the optical axis of the optical lens, thereby telecentrically positioning the optical lens in image space. It is assumed that the total optical power of the first lens group is higher than the total optical power of the second lens group. Furthermore, the second lens group is configured as follows:

[0038] - The negative focal length of the first aspherical lens element is -1.2mm to -0.8mm, the refractive index is 1.60 to 1.75, and the Abbe number is 17 to 25;

[0039] - The second aspherical lens element has a positive focal length of 2.1mm to 2.5mm, a refractive index of 1.50 to 1.60, and an Abbe number of 50 to 60;

[0040] - The third aspherical lens element has a positive focal length of 3.8mm to 4.4mm, a refractive index of 1.60 to 1.75, and an Abbe number of 15 to 30.

[0041] It should also be noted that if, in the second lens group, the negative focal length of the first aspherical lens element is -1.08 mm, the positive focal length of the second aspherical lens element is 2.28 mm, and the positive focal length of the third aspherical lens element is 4.12 mm, then the optical lens can provide an image diagonal of 3.8 mm. Meanwhile, those skilled in the art will recognize that the focal lengths of the aspherical lens elements in the second lens group (and one or more aspherical lens elements in the first lens group, if needed) can be scaled according to the specific application. For example, if an image diagonal of 4.18 mm is required (i.e., an increase of 10%), then the preferred focal lengths of the aspherical lens elements in the second lens group should be in the range of -1.32 mm to -0.88 mm (first aspherical lens element), in the range of 2.31 mm to 2.75 mm (second aspherical lens element), and in the range of 4.18 mm to 4.84 mm (third aspherical lens element) (i.e., the upper and lower limits of each of these ranges are also changed by 10%).

[0042] Figure 1A schematic block diagram of an optical lens 100 according to an exemplary embodiment is shown. The optical lens 100 includes a first (left) lens group 102 and a second (right) lens group 104, which are arranged sequentially along the optical axis 106 of the optical lens 100. The first lens group 102 includes a first aspherical lens element 102-1, a second aspherical lens element 102-2, and a third aspherical lens element 102-3, which are arranged sequentially along the optical axis 106 of the optical lens 100. The second lens group 104 includes a first aspherical lens element 104-1, a second aspherical lens element 104-2, and a third aspherical lens element 104-3, which are arranged sequentially after the first lens group 102 along the optical axis 106 of the optical lens 100. The primary function of the first aspherical lens element 104-1 and the second aspherical lens element 104-2 in the second lens group 104 is to correct chromatic aberration that may exist in the optical lens 100, while the primary function of the third aspherical lens element 104-3 in the second lens group 104 is to refract the principal ray substantially parallel to the optical axis 106 of the optical lens 100. In view of these functions, each of the aspherical lens elements 104-1, 104-2, and 104-3 in the second lens group 104 can be configured to have a focal length, refractive index, and Abbe number within the aforementioned corresponding numerical range. The first aspherical lens elements 102-1, 102-2, and 102-3 in the first lens group 102 are primarily used to correct other types of aberrations that may exist in the optical lens 100 (although these aspherical lens elements can also slightly correct chromatic aberration). These types of aberrations may include, but are not limited to, third-order aberrations (also known as Seidel aberrations, including spherical aberration, coma, astigmatism, field curvature aberration, distortion aberration, etc.) and higher-order aberrations (e.g., 5th-order, 7th-order, etc.). The first aspherical lens element 102-1, the second aspherical lens element 102-2, and the third aspherical lens element 102-3 are used to correct one or more of these aberrations according to specific applications and user preferences. Preferably, the positive focal length of the first aspherical lens element 102-1 is 3mm to 4mm, the positive focal length of the second aspherical lens element 102-2 is 5mm to 10mm, and the positive focal length of the third aspherical lens element 102-3 is 5mm to 10mm. The aspherical lens elements of the first lens group 102 and the second lens group 104 can be made of optical glass, transparent plastic, or polymer using any of the existing lens manufacturing techniques (e.g., molding, casting, die casting, etc.).

[0043] It should be noted that, Figure 1The number and shape of the aspherical lens elements shown in the diagram constituting each of the first lens group 102 and the second lens group 104 are not intended to constitute any limitation on the invention, but are merely intended to provide a general idea of ​​how to implement aspherical lens elements within an optical lens 100. For example, the first lens group 102 may be represented by a single aspherical lens element used to correct one or more aberrations of interest. It is well known that no single lens element is perfect, and all lens elements will cause different aberrations. Ideally, the sum of each aberration of all lens elements is zero. This can be understood as each lens element of the optical lens being used to eliminate all aberrations caused by the remaining lens elements of the optical lens. Therefore, the first lens group 102 may have fewer or more than three aspherical lens elements, as long as the first lens group 102 can optimally correct one or more aberrations caused by the aspherical lens elements of the second lens group 104. Similarly, the shapes of the first aspherical lens element 104-1 and the second aspherical lens element 104-2 in the second lens group 104 should be chosen such that the chromatic aberration of the optical lens is appropriately fixed. At the same time, the second lens group 104 preferably has at least three aspherical lens elements—if the number of aspherical lens elements is less than three, the lens performance may be reduced.

[0044] The first lens group 102 and the second lens group 104 can also be configured based on other desired lens parameters. In other words, the shape of the aspherical lens elements of the first lens group 102 and the second lens group 104 can be adjusted to obtain the desired lens parameters. For example, the first lens group 102 and the second lens group 104 can be used to operate in the light wavelength range of 400nm to 850nm (this operating wavelength range is preferred and can be extended, but at the expense of the performance of the optical lens 100). Alternatively, the first lens group 102 and the second lens group 104 can be configured such that the effective focal length of the optical lens 100 is less than or equal to 2.3mm and / or the f-number is greater than or equal to 2.8. Alternatively, the first lens group 102 and the second lens group 104 can be configured such that the diagonal FOV of the optical lens 100 is -40° to +40°. Alternatively, the first lens group 102 and the second lens group 104 can be configured such that the ratio of the total track length (TTL) to the full image diagonal is less than or equal to 1.3.

[0045] In one embodiment, the optical lens 100 may further include an aperture stop 108 located between the second aspherical lens element 102-2 and the third aspherical lens element 102-3 in the first lens group 102.

[0046] A non-limiting example is now provided to illustrate how to perform numerical calculations for the design of optical lens 100. In this example, the following calculation formula can be used:

[0047]

[0048] Where z is sag or arc vector, c is curvature, r is radial coordinate, k is conic coefficient, and α is the nth even-numbered aspherical coefficient. This calculation formula is well-known in the art, therefore its detailed explanation is omitted here. Using this formula, the following lens design parameter table can be obtained (it should be noted that the Abbe numbers mentioned in Tables 1 and 2 are optimized for the wavelength range of 400nm to 850nm):

[0049] Table 1: The first four lens design parameters in the above formula. Each row represents a lens surface.

[0050]

[0051] Table 2: The last four lens design parameters in the above formula. Each row represents a lens surface.

[0052]

[0053]

[0054] Figure 2 A schematic block diagram of a spectroscopic camera 200 including an optical lens 100 according to an exemplary embodiment is shown. The spectroscopic camera 200 also includes a spectral filter 202 and an image sensor 204. The image sensor 204 is arranged behind the optical lens 100 along the optical axis 106 of the optical lens 100, and the spectral filter 202 is arranged between the optical lens 100 and the image sensor 204. The spectral filter 202 can be represented by any one or more color filters. Some examples of color filters may include, but are not limited to, absorption filters, interference-based filters (e.g., thin-film filters or Fabry-Perot filters), metasurface color filters, quantum dot color filters, or any combination thereof. Alternatively or additionally, the spectroscopic camera 200 may also include other similar spectral filters (not shown) arranged directly on the image sensor 204.

[0055] Figure 3 This illustrates how the optical lens 100 in the spectroscopic camera 200 refracts light. It can be seen that the third aspherical lens element 104-3 of the second lens group 104, which is substantially parallel to the optical axis 106 of the optical lens 100, refracts the principal ray. This confirms that the optical lens 100 is telecentric in image space.

[0056] Figure 4A and Figure 4BThe dependence of the F-Tan (Theta) distortion (in percentage) and field curvature (in millimeters) of the optical lens 100 on the object field angle at different light wavelengths is shown. More specifically, the optical lens 100 designed according to the numerical examples given above has achieved these dependencies. Figure 4B In Chinese, the text description "tan (or sag) displacement, XXX nm" means that the tangential (or sagittal) ray at a wavelength of XXX nm acquires a given dependence or curve. Technicians can use this information... Figure 4A and Figure 4B The dependence on the field angle clearly demonstrates the performance of the optical lens 100. Ideally, for all values ​​of the object field angle, the values ​​of F-Tan (Theta) distortion and field curvature are equal to 0.

[0057] Figure 5 The dependence of the modulus of the optical transfer function (OTF) of optical lens 100 on spatial frequency (period / mm) at different image field heights (in mm) is shown. Wavelength dependence and diffraction effects between 410 nm and 850 nm were considered in the OTF calculation. Figure 5 In this context, the text "Image field XX mm, Tan (and / or Sag)" means that a given curve or dependency is related to the tangential (and / or sagittal) rays at an image field height of XX mm. Similarly, technicians can... Figure 5 The dependencies clearly demonstrate how well the optical lens 100 performs. Ideally, these dependencies follow the diffraction limit of the OTF modulus of the optical lens 100.

[0058] Although exemplary embodiments of the invention have been described herein, it should be noted that various changes and modifications may be made to the embodiments of the invention without departing from the legal protection defined by the appended claims. In the appended claims, the word "comprising" does not exclude other elements or operations, and the indefinite articles "a" or "an" do not exclude a plurality. The enumeration of certain measures in dissimilar appended claims does not imply that combinations of these measures cannot be used to obtain an advantage.

Claims

1. An optical lens, characterized in that, include: A first lens group, wherein the first lens group is arranged along the optical axis of the optical lens, and the first lens group includes at least one aspherical lens element. A second lens group, wherein the second lens group is arranged after the first lens group along the optical axis of the optical lens, the second lens group includes a first aspherical lens element, a second aspherical lens element, and a third aspherical lens element arranged sequentially along the optical axis of the optical lens. The first and second aspherical lens elements are used to correct the chromatic aberration of the optical lens, and the third aspherical lens element is used to refract the principal ray substantially parallel to the optical axis of the optical lens, wherein: The total optical power of the first lens group is higher than the total optical power of the second lens group; The negative focal length of the first aspherical lens element is -1.2 mm to -0.8 mm, the refractive index is 1.60 to 1.75, and the Abbe number is 17 to 25; The second aspherical lens element has a positive focal length of 2.1 mm to 2.5 mm, a refractive index of 1.50 to 1.60, and an Abbe number of 50 to 60; The third aspherical lens element has a positive focal length of 3.8 mm to 4.4 mm, a refractive index of 1.60 to 1.75, and an Abbe number of 15 to 30.

2. The optical lens according to claim 1, characterized in that, The first lens group and the second lens group are used to operate in the light wavelength range of 400nm to 850nm.

3. The optical lens according to claim 1 or 2, characterized in that, The first lens group and the second lens group are configured such that the effective focal length of the optical lens is less than or equal to 2.3mm.

4. The optical lens according to any one of claims 1 to 3, characterized in that, The first lens group and the second lens group are configured such that the diagonal field of view of the optical lens is –40° to +40°.

5. The optical lens according to any one of claims 1 to 4, characterized in that, The first lens group and the second lens group are configured such that the ratio of the total trajectory length to the diagonal of the entire image is less than or equal to 1.

3.

6. The optical lens according to any one of claims 1 to 5, characterized in that, The first aspherical lens element of the first lens group includes a first aspherical lens element with a positive focal length of 3mm to 4mm, a second aspherical lens element with a positive focal length of 5mm to 10mm, and a third aspherical lens element with a positive focal length of 5mm to 10mm.

7. The optical lens according to claim 6, characterized in that, It also includes an aperture stop, wherein the aperture stop is located between the second aspherical lens element and the third aspherical lens element in the first lens group.

8. The optical lens according to any one of claims 1 to 7, characterized in that, The first lens group and the second lens group are configured such that the f-number of the optical lens is greater than or equal to 2.

8.

9. A spectroscopic camera, characterized in that, include: Optical lens according to any one of claims 1 to 8; An image sensor, wherein the image sensor is arranged behind the optical lens along the optical axis of the optical lens.

10. The spectroscopic camera according to claim 9, characterized in that, It also includes a spectral filter, wherein the spectral filter is disposed between the optical lens and the image sensor.

11. The spectral camera according to claim 9, characterized in that, It also includes a spectral filter, wherein the spectral filter is directly disposed on the image sensor.

12. The spectral camera according to claim 10 or 11, characterized in that, The spectral filter includes at least one color filter.

13. The spectroscopic camera according to claim 11, characterized in that, Each of the spectral filters arranged between the optical lens and the image sensor, and the spectral filters arranged directly on the image sensor, includes at least one color filter.

Images