Short-wave infrared color imaging method and optical system

Abstract

The application discloses a short-wave infrared color imaging method and an optical system, relates to the field of photoelectric imaging technology, and mainly receives, converges and splits short-wave infrared light waves to form three sub-band light waves which are respectively focused to three colloidal quantum dot short-wave infrared imaging devices. When color imaging is needed, twice splitting is performed to obtain three sub-band image information which is simultaneously transmitted to the input end of a color display to realize short-wave infrared multi-band common optical path color imaging and solve the problem that color imaging cannot be realized. The main technical scheme of the application is as follows: a short-wave infrared color imaging optical system comprises a common optical path objective lens, a light splitting component and three imaging devices; the common optical path objective lens is used for receiving and converging incident light waves which are then emitted to the light splitting component; the light splitting component is used for performing dichroic splitting on the converged light waves to form three sub-band light waves which are respectively imaged on the three imaging devices; and the wavelength ranges of the different sub-band light waves are different. The application is mainly used for short-wave infrared color imaging.

Description

Technical Field

[0001] This invention relates to the field of photoelectric imaging technology, and in particular to a short-wave infrared color imaging method and optical system. Background Technology

[0002] Utilizing short-wave infrared bands for environmental target detection and imaging has gradually emerged as a new practical application. Short-wave infrared detection and imaging technology primarily utilizes light energy in the 1-micron to 3-micron band (or a portion thereof) for receiving, detecting, and imaging. Existing short-wave infrared detection and imaging methods are based on indium gallium arsenide (InGaAs) short-wave infrared detectors. However, due to their high cost, they typically use only a single-path optical system and a single short-wave infrared detector to receive and detect incident light energy. This results in acquiring only black-and-white (or monochrome) grayscale image information within a single band. The spectral information and light energy utilization of the short-wave band are insufficient, and using only grayscale information is not conducive to distinguishing different types of targets in the environment, leading to less than ideal target detection, observation, and identification results. Summary of the Invention

[0003] In view of this, the present invention provides a short-wave infrared color imaging method and optical system, which mainly focuses and splits short-wave infrared light waves, focusing them onto different imaging devices, and obtains color imaging through image fusion display.

[0004] To achieve the above objectives, the present invention mainly provides the following technical solutions: On one hand, the present invention provides a short-wave infrared color imaging optical system, comprising: Common-path objective lens, beam splitter assembly, and three imaging devices; The common-path objective is used to receive and converge the incident light wave, and then output the converged light wave to the beam splitter. The beam splitter is used to perform dichroic beam splitting on the converged light wave, dividing it into three sub-band light waves, which are then imaged onto three colloidal quantum dot short-wave infrared imaging devices respectively. The wavelength ranges of the three sub-bands of light are different.

[0005] The beam splitting components include a first beam splitting component and a second beam splitting component; The three imaging devices include a first imaging device, a second imaging device, and a third imaging device; The first beam splitter is used to perform dichroic beam splitting on the incident light wave to form a first photonic band light wave and an intermediate photonic band light wave. The first photonic band light wave is imaged on a first imaging device, and the intermediate photonic band light wave is transmitted to a second beam splitter. The second beam splitter is used to split the intermediate photonic band light wave into a second photonic band light wave and a third photonic band light wave. The second photonic band light wave is imaged on a second imaging device, and the third photonic band light wave is imaged on a third imaging device.

[0006] The first beam splitting component includes a first prism and a second prism. The first prism is located between the second prism and the common optical path objective lens, and the surface of the first prism relative to the second prism forms a 45-degree angle with the optical axis of the common optical path objective lens. The second beam splitting assembly includes a third prism and a fourth prism. The third prism is located between the fourth prism and the first beam splitting assembly, and the surface of the third prism relative to the fourth prism forms a 45-degree angle with the optical axis of the common-path objective lens. A first dichroic film is disposed on the surface of the first prism opposite to the second prism. The first dichroic film is used to perform a first dichroic beam splitting on the incident light wave: reflection to form a first photon waveband light wave, and transmission to form an intermediate photon waveband light wave. A second dichroic film is disposed on the surface of the third prism opposite to the fourth prism. The second dichroic film is used to perform a second dichroic beam splitting on the incident light wave: reflection to form a second photon waveband light wave, and transmission to form a third photon waveband light wave. Alternatively, a first dichroic film is disposed on the surface of the first prism opposite to the second prism. The first dichroic film is used to perform a first dichroic split on the incident light wave: reflection to form an intermediate photon band light wave, and transmission to form a first photon band light wave. A second dichroic film is disposed on the surface of the third prism opposite to the fourth prism. The second dichroic film is used to perform a second dichroic split on the incident light wave: reflection to form a second photon band light wave, and transmission to form a third photon band light wave.

[0007] Among them, the first prism and the second prism are glued together, and the third prism and the fourth prism are glued together. Alternatively, an air gap can be preset between the first and second prisms, and between the third and fourth prisms.

[0008] Among them, the wavelength ranges of the first photon band, the second photon band, and the third photon band are within the shortwave infrared band, and the wavelength ranges of the light waves in the first photon band, the second photon band, and the third photon band do not overlap with each other.

[0009] Among them, the first imaging device, the second imaging device and the third imaging device are all colloidal quantum dot short-wave infrared imaging devices, with a response wavelength range of at least 1 micrometer to 2.5 micrometers, and are located on the common optical path object mirror focal plane.

[0010] The optical system also includes: A compensation mirror is located between the first beam splitter and the first imaging device.

[0011] Among them, the common-path objective lens is a coaxial optical system in the form of four groups of six elements, including a first lens, a second lens, a third lens and a fourth lens arranged coaxially in sequence in the direction close to the beam splitter; The first lens is used at least for the transmission and focusing of converging light waves; the second and third lenses are used at least for chromatic aberration correction of the light waves transmitted by the first lens; and the fourth lens is used at least for adjusting the position of the light waves transmitted by the third lens. The first lens, the second lens, the third lens, and the fourth lens are all spherical lenses; Alternatively, at least one of the first lens, second lens, third lens, and fourth lens may be an aspherical lens.

[0012] The common-path objective lens also includes an aperture stop, which is positioned between the second lens and the third lens.

[0013] On the other hand, the present invention also provides a short-wave infrared color imaging method, based on any one of the above-mentioned short-wave infrared color imaging optical systems, the method comprising: The incident light wave in the short-wave band is split into three sub-bands by two dichroic beam splits, and then imaged onto three colloidal quantum dot short-wave infrared imaging devices respectively. Obtain the display requirements and determine the type of display requirements; When the display requirement is to display a specific sub-band, the system acquires the target image and determines whether the target imaging device is the imaging device corresponding to a single reflection beam split. If so, the image signal of the target imaging device is mirrored and displayed; otherwise, the image signal of the target imaging device is displayed directly. When the display requirement is color display, the image signal of the imaging device corresponding to the single reflection beam split is mirrored, and then the image signals of all three imaging devices are displayed simultaneously.

[0014] The short-wave infrared color imaging method and optical system proposed in this invention involve a common-path objective lens receiving and focusing short-wave infrared incident light waves from an environmental target. This light is then transmitted to a beam splitter, where it undergoes dichroic beam splitting to divide the light into at least two sub-wavelengths. These sub-wavelengths are then focused onto three corresponding imaging devices. The image of one sub-wavelength band can be displayed individually, providing an image corresponding to that single sub-wavelength band. Alternatively, any two sub-wavelength images can be combined for display, providing an image corresponding to both sub-wavelength bands. Furthermore, the image information from all three imaging devices can be simultaneously output to a color display, thus achieving color imaging of the environmental target in the short-wave infrared band—that is, realizing short-wave infrared multi-band color imaging. This invention not only improves target feature identification (especially short-wave infrared spectral features) but also features small size, light weight, low cost, compact structure, and ease of use, making it particularly suitable for the actual market demand for short-wavelength imaging instruments and offering significant advantages. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the first short-wave infrared color imaging optical system provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a second short-wave infrared color imaging optical system provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the third short-wave infrared color imaging optical system provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the fourth short-wave infrared color imaging optical system provided in an embodiment of the present invention; Figure 5 A simulation diagram of the field curvature results of a shortwave infrared color imaging optical system provided in an embodiment of the present invention; Figure 6 A simulation diagram of the distortion results of a short-wave infrared color imaging optical system provided in an embodiment of the present invention; Figure 7 A simulation diagram of the MTF results of a short-wave infrared color imaging optical system provided in an embodiment of the present invention; Figure 8 A flowchart of a shortwave infrared color imaging method provided in an embodiment of the present invention; Among them, the common-path objective lens-100, the first lens-110, the second lens-120, the first sub-lens-121, the second sub-lens-122, the third lens-130, the third sub-lens-131, the fourth sub-lens-132, the fourth lens-140, the aperture-150, the beam splitter assembly-200, the first beam splitter assembly-210, the first prism-211, the second prism-212, the second beam splitter assembly-220, the third prism-221, the fourth prism-222, the compensating mirror-300, the first imaging device-400, the second imaging device-500, and the third imaging device-600. Detailed Implementation

[0016] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following detailed description, in conjunction with the accompanying drawings and preferred embodiments, describes the specific implementation, structure, features, and effects of a short-wave infrared color imaging optical system proposed according to the present invention.

[0017] like Figure 1 , Figure 2 , Figure 3 , Figure 4 As shown, this embodiment of the invention provides a short-wave infrared color imaging optical system, comprising: Common-path objective lens 100, beam splitter 200, and three imaging devices; The common-path objective lens 100 is used to receive and converge the incident light wave, and then output the converged light wave to the beam splitter 200. The beam splitter 200 is used for dichroic beam splitting, which divides the converged light wave into three sub-band light waves, which are then imaged onto three imaging devices respectively. The three sub-bands of light waves have different wavelength ranges and do not overlap.

[0018] The common-path objective lens 100 is used to receive and converge short-wave infrared incident light waves from environmental targets, completing focused imaging. Furthermore, through its optical design, the common-path objective lens 100 can also correct optical system aberrations such as spherical aberration, coma, field curvature, astigmatism, distortion, and chromatic aberration, achieving excellent system imaging quality. The converged light waves are then emitted to the beam splitter 200. The beam splitter 200 utilizes a dichroic beam splitter film (the coated surface is at a 45-degree angle to the optical axis of the common-path objective lens) designed and deposited to meet technical requirements, splitting the incident light waves into reflected and transmitted sub-band light waves. This allows for two dichroic beam splits of the short-wave infrared light waves, resulting in three sub-band light waves. The different sub-band light waves emitted by the beam splitter 200 will be imaged onto the corresponding imaging devices. After photoelectric conversion by the imaging devices, the corresponding image information of each sub-band is obtained. The sub-band images can be displayed individually, or different combinations of images can be made. The corresponding image information of two or three sub-band light waves can be simultaneously output to a color display, so that monochrome or color display of images corresponding to different sub-band light waves can be realized, especially the display of color images in the short-wave infrared band.

[0019] The beam splitter 200 is located between the common-path objective lens 100 and the imaging devices. It can be understood that the common-path objective lens 100 is used to receive and converge the incident light waves, the beam splitter 200 is located on the optical axis of the common-path objective lens 100, and the three imaging devices are respectively located on the optical axis of the optical path after the beam splitter 200 splits the light.

[0020] It is worth noting that this application uses only a single common-path objective lens 100, meaning that the beam-splitting assembly 200 and multiple imaging devices share one imaging objective lens. Furthermore, a compensation lens is used to ensure better consistency of design parameters such as focal length and distortion deviation across the various sub-bands after beam splitting, thereby maximizing the image quality and observation effect of multi-band color imaging. The common-path objective lens 100 uses the most commonly used colorless optical glass material, which offers stable performance, low cost, and high quality. The specific composition of the common-path objective lens 100 will be described in more detailed embodiments later.

[0021] The short-wave infrared color imaging method and optical system proposed in this invention involve a common-path objective lens receiving and focusing short-wave infrared incident light waves from an environmental target. This light is then transmitted to a beam splitter, where it undergoes dichroic beam splitting to divide the light into at least two sub-wavelengths. These sub-wavelengths are then focused onto three corresponding imaging devices. The image of one sub-wavelength band can be displayed individually, providing an image corresponding to that single sub-wavelength band. Alternatively, any two sub-wavelength images can be combined for display, providing an image corresponding to both sub-wavelength bands. Furthermore, the image information from all three imaging devices can be simultaneously output to a color display, thus achieving color imaging of the environmental target in the short-wave infrared band—that is, realizing short-wave infrared multi-band color imaging. This invention not only improves target feature identification (especially short-wave infrared spectral features) but also features small size, light weight, low cost, compact structure, and ease of use, making it particularly suitable for the actual market demand for short-wavelength imaging instruments and offering significant advantages.

[0022] As mentioned above, after the converging light beam emitted from the common-path objective lens 100 passes through the beam splitter 200, the number of beam splitting paths can be multiple, such as two or three. In the following embodiment, the beam splitter 200 is used to form three photonic sub-bands as an example. The sub-bands of the three beams can be selected as needed, but they must satisfy the following requirements: the wavelength ranges of the first, second, and third photonic sub-bands must be within the short-wave infrared band, and the wavelength ranges of the first, second, and third photonic sub-bands must be different and not overlap. For example, the wavelength range of the first photonic sub-band can be greater than or equal to 1 micrometer and less than 1.5 micrometers; the wavelength range of the second photonic sub-band can be greater than or equal to 1.5 micrometers and less than 2 micrometers; and the wavelength range of the third photonic sub-band can be greater than or equal to 2 micrometers and less than or equal to 2.5 micrometers. Alternatively, the wavelength range of the first photon band light wave can be greater than or equal to 1 micrometer and less than 1.2 micrometers; the wavelength range of the second photon band light wave can be greater than or equal to 1.2 micrometers and less than 2.3 micrometers; and the wavelength range of the third photon band light wave can be greater than or equal to 2.3 micrometers and less than or equal to 2.5 micrometers. Other configurations are also possible, which will not be listed here. The beam splitting component 200 includes a first beam splitting component 210 and a second beam splitting component 220. The three imaging devices include a first imaging device 400, a second imaging device 500, and a third imaging device 600. The first beam splitter 210 is used to perform dichroic beam splitting on the incident light wave, dividing it into a first photonic waveband and an intermediate photonic waveband. The first photonic waveband is imaged on the first imaging device 400, and the intermediate photonic waveband is emitted to the second beam splitter 220. The second beam splitter 220 is used to divide the intermediate photonic waveband into a second photonic waveband and a third photonic waveband. The second photonic waveband is imaged on the second imaging device 500, and the third photonic waveband is imaged on the third imaging device 600.

[0023] The location of the first beam splitter 210 within the second beam splitter 220 can be varied, such as in one embodiment, for example... Figure 1-2As shown, the first beam-splitting component 210 can be located between the second beam-splitting component 220 and the common-path objective lens 100, meaning the first beam-splitting component 210 and the second beam-splitting component 220 are arranged sequentially on the outgoing light path of the converging light wave from the common-path objective lens 100. Alternatively, the first beam-splitting component 210 and the second beam-splitting component 220 are arranged sequentially on the light-emitting side of the common-path objective lens 100, along the optical axis of the common-path objective lens 100 in a direction away from the common-path objective lens 100. The first imaging device 400 is located on the path of the first photon band light wave reflected by the first beam-splitting component 210, the second imaging device 500 is located on the path of the second photon band light wave reflected by the second beam-splitting component 220, and the third imaging device 600 is located on the path of the third photon band light wave transmitted by the second beam-splitting component 220.

[0024] Short-wave infrared light waves from environmental targets are received and focused by the common-path objective lens 100, and then transmitted to the first beam splitter 210. After being split into two beams by dichroism by the first beam splitter 210, the two beams can be perpendicular to each other. The first beam splitter is reflected by the first beam splitter 210 and focused onto the first imaging device 400. The second beam splitter is transmitted through the first beam splitter 210 and split again by dichroism by the second beam splitter 220, becoming two beams perpendicular to each other. The second beam splitter is reflected by the second beam splitter 220 and focused onto the second imaging device 500. The third beam splitter is transmitted through the second beam splitter 220 and focused onto the third imaging device 600.

[0025] Alternatively, in another implementation, it can be as follows: Figure 3-4 As shown, the first beam-splitting component 210 may be located on the output optical path of the converging light wave of the common-path objective lens 100, while the first beam-splitting component 210 and the second beam-splitting component 220 may be arranged in a direction perpendicular to the optical axis of the common-path objective lens 100. The first imaging device 400 is located on the path of the first photonic band light wave projected by the first beam-splitting component 210, the second imaging device 500 is located on the path of the second photonic band light wave reflected by the second beam-splitting component 220, and the third imaging device 600 is located on the path of the third photonic band light wave transmitted by the second beam-splitting component 220.

[0026] Short-wave infrared light waves from environmental targets are received and focused by the common-path objective lens 100, and then transmitted to the first beam splitter 210. After being split into two beams by dichroism by the first beam splitter 210, the two beams can be perpendicular to each other. The first beam splitter is transmitted by the first beam splitter 210 and focused onto the first imaging device 400. The second beam splitter is reflected by the first beam splitter 210 and split again by the second beam splitter 220, becoming two beams perpendicular to each other. The second beam splitter is reflected by the second beam splitter 220 and focused onto the second imaging device 500. The third beam splitter is transmitted by the second beam splitter 220 and focused onto the third imaging device 600.

[0027] Taking the wavelength range of the first photon band (greater than or equal to 1 micrometer and less than 1.5 micrometers), the second photon band (greater than or equal to 1.5 micrometers and less than 2 micrometers), and the third photon band (greater than or equal to 2 micrometers and less than or equal to 2.5 micrometers) as an example, after the optical system is applied, three short-wave infrared sub-lights of 1 micrometer to 1.5 micrometers, 1.5 micrometers to 2 micrometers, and 2 micrometers to 2.5 micrometers are focused onto three imaging devices, respectively, to obtain short-wave infrared multi-band common-path color imaging image information. The setting of the three photon bands fully utilizes the incident light energy from the short-wave bands of the target scene, that is, it fully utilizes the light energy and spectral information of the three short-wave bands: 1 micrometer to 1.5 micrometers, 1.5 micrometers to 2 micrometers, and 2 micrometers to 2.5 micrometers.

[0028] In a more specific implementation, such as Figure 1-4 As shown, the first beam splitter 210 includes a first prism 211 and a second prism 212. The first prism 211 is located between the second prism 212 and the common-path objective lens 100, and the surface of the first prism 211 relative to the second prism 212 forms a 45-degree angle with the optical axis of the common-path objective lens 100. The second beam splitter 220 includes a third prism 221 and a fourth prism 222. The third prism 221 is located between the fourth prism 222 and the first beam splitter 210, and the surface of the third prism 221 relative to the fourth prism 222 forms a 45-degree angle with the optical axis of the common-path objective lens 100.

[0029] To achieve transmission and reflection of incident light, thus realizing beam splitting, dichroic films are provided on the first prism 211 and the third prism 221. Figure 1-2 The illustrated embodiments, and Figure 3-4 In the embodiments shown, the dichroic films disposed on the first prism 211 and the third prism 221 are different. The following will describe the two embodiments separately with examples: Firstly, such as Figure 1-2As shown, a first dichroic film is disposed on the surface of the first prism 211 opposite to the surface of the second prism 212, which performs the first beam splitting of the incident light wave: the reflection of the first dichroic film forms a light wave in the first photon band, and its transmission forms a light wave in the intermediate photon band. A second dichroic film is disposed on the surface of the third prism 221 opposite to the surface of the fourth prism 222, which performs the second beam splitting of the incident light wave: the reflection of the second dichroic film forms a light wave in the second photon band, and its transmission forms a light wave in the third photon band.

[0030] The specific shapes of the first prism 211, the second prism 212, the third prism 221, and the fourth prism 222 can also be set as needed. A more specific implementation is provided below, aiming to ensure that light waves of different photon bands can have the same imaging quality; in other words, to ensure that the cumulative propagation length of light waves imaged on different imaging devices is consistent in the prisms or compensating mirrors. Specifically, the first prism 211, the second prism 212, the third prism 221, and the fourth prism 222 are all isosceles right-angle prisms. The first right-angled surface of the first prism 211 faces the common-path objective lens 100 and is perpendicular to the optical axis of the common-path objective lens 100; the inclined surface of the first prism 211 is parallel to the inclined surface of the second prism 212. The first right-angled surface of the third prism 221 faces the second prism 212 and is perpendicular to the optical axis of the common-path objective lens 100; the inclined surface of the third prism 221 is parallel to the inclined surface of the fourth prism 222. The centers of the inclined surfaces of the first prism 211, the second prism 212, the third prism 221, and the fourth prism 222 all intersect the optical axis of the common-path objective lens 100. A first dichroic film is coated on the inclined surface of the first prism 211, designed to have high reflectivity (1-1.5 μm) and high transmittance (1.5-2.5 μm). A second dichroic film is coated on the inclined surface of the third prism 221, designed to have high reflectivity (1.5-2 μm) and high transmittance (2-2.5 μm).

[0031] The first imaging device 400 is opposite to the second right-angled surface of the first prism 211 and is located on the optical axis after reflection by the first prism 211 and transmission through the compensating mirror, and is located at the image-side focal plane of the common-path objective lens 100. The second imaging device 500 is opposite to the second right-angled surface of the third prism 221 and is located on the optical axis after reflection by the third prism 221, and is located at the image-side focal plane of the common-path objective lens 100. The third imaging device 600 is opposite to the right-angled surface of the fourth prism 222 on the side away from the common-path objective lens 100, and is located on the optical axis after transmission by the fourth prism 222, and is located at the image-side focal plane of the common-path objective lens 100.

[0032] In specific assembly, the relationship between the inclined surface of the first prism 211 and the inclined surface of the third prism 221 can be as follows: Figure 1As shown, they are perpendicular to each other, meaning the second right-angled faces of the first prism 211 and the third prism 221 are arranged in opposite directions. Alternatively, they can be arranged as follows: Figure 2 As shown, the inclined surfaces of the first prism 211 and the third prism 221 are parallel to each other, meaning that the second right-angled surfaces of the first prism 211 and the third prism 221 are oriented in the same direction. Alternatively, there can be other configurations. It can be understood that, while ensuring that their principal cross-sections are identical, both the first beam-splitting assembly 210 and the second beam-splitting assembly 220 can be rotated to any position using the optical axis of the common optical path objective lens 100 as the axis. This is not limited to the position shown in the figure; the first imaging device 400 and the second imaging device 500 can adaptively adjust their positions.

[0033] Secondly, such as Figure 3-4 As shown, a first dichroic film is disposed on the surface of the first prism 211 relative to the surface of the second prism 212. The first dichroic film is used to perform a first dichroic split on the incident light wave: reflection to form an intermediate photon band light wave, and transmission to form a first photon band light wave. A second dichroic film is disposed on the surface of the third prism 221 relative to the surface of the fourth prism 222. The second dichroic film is used to perform a second dichroic split on the incident light wave: reflection to form a second photon band light wave, and transmission to form a third photon band light wave.

[0034] The specific shapes of the first prism 211, the second prism 212, the third prism 221, and the fourth prism 222 can also be set as needed. A more specific implementation is provided below, aiming to ensure that light waves of different photon bands can have the same imaging quality; in other words, to ensure that the cumulative propagation length of light waves imaged on different imaging devices is consistent in the prisms or compensating mirrors. Specifically, the first prism 211, the second prism 212, the third prism 221, and the fourth prism 222 are all isosceles right-angle prisms. The first right-angled surface of the first prism 211 faces the common-path objective lens 100 and is perpendicular to the optical axis of the common-path objective lens 100; the inclined surface of the first prism 211 is parallel to the inclined surface of the second prism 212. The first right-angled surface of the third prism 221 faces the first prism 211 and is parallel to the optical axis of the common-path objective lens 100; the inclined surface of the third prism 221 is parallel to the inclined surface of the fourth prism 222. The centers of the inclined surfaces of the first prism 211 and the second prism 212 intersect the optical axis of the common-path objective lens 100. The line connecting the centers of the inclined surfaces of the third prism 221 and the fourth prism 222 to the center of the inclined surface of the first prism 211 is perpendicular to the optical axis of the objective lens 100. A first dichroic film is coated on the inclined surface of the first prism 211, and is designed to have high transmittance of light waves from 1 micrometer to 1.5 micrometers and high reflectance of light waves from 1.5 micrometers to 2.5 micrometers. A second dichroic film is coated on the inclined surface of the third prism 221, and is designed to have high reflectance of light waves from 1.5 micrometers to 2 micrometers and high transmittance of light waves from 2 micrometers to 2.5 micrometers.

[0035] In specific assembly, the relationship between the inclined surface of the first prism 211 and the inclined surface of the third prism 221 can be as follows: Figure 3 As shown, they are perpendicular to each other, meaning the first right-angled face of the first prism 211 and the second right-angled face of the third prism 221 are arranged in the same direction. Alternatively, they can be arranged as follows: Figure 4 As shown, the inclined surfaces of the first prism 211 and the third prism 221 are parallel to each other, meaning the first right-angled surface of the first prism 211 and the second right-angled surface of the third prism 221 are arranged in opposite directions. Alternatively, there can be other arrangements. It can be understood that, while ensuring that both the first beam-splitting assembly 210 and the second beam-splitting assembly 220 have the same principal cross-section, they can both rotate to any position with the optical axis perpendicular to the common optical path objective lens 100 as the axis, and are not limited to the position shown in the figure. The first imaging device 400 and the second imaging device 500 can adaptively adjust their positions.

[0036] The first prism 211, the second prism 212, the third prism 221, and the fourth prism 222 can all be made of commonly used K9 optical glass, or other optical materials that meet the requirements. The side lengths of the right-angled faces of the first prism 211, the second prism 212, the third prism 221, and the fourth prism 222 are determined according to the specific technical requirements. The same applies to the edge lengths of the first prism 211, the second prism 212, the third prism 221, and the fourth prism 222.

[0037] The positional relationship between the first prism 211 and the second prism 212, the third prism 221 and the fourth prism 222 can be varied. For example, the first prism 211 and the second prism 212 can be glued together, and the third prism 221 and the fourth prism 222 can be glued together to form two glued prisms. This can ensure the relative position stability of the first prism 211 and the second prism 212, the third prism 221 and the fourth prism 222, which is convenient for assembly and adjustment and reduces stray light interference.

[0038] In another embodiment, an air gap may be preset between the first prism 211 and the second prism 212, and an air gap may be preset between the third prism 221 and the fourth prism 222. The gaps may be maintained by shims, but it is understood that the gaps are tiny slits and cannot be set too large in order to ensure image quality. For example, the width of the slits may be 0.2 mm, 0.05 mm, etc.

[0039] In one embodiment, the first imaging device 400, the second imaging device 500, and the third imaging device 600 are all colloidal quantum dot short-wave infrared imaging devices, with a response wavelength range covering 1 micrometer to 2.5 micrometers. It can be understood that "coverage" refers to the ability to respond to light waves with wavelengths of at least 1 micrometer to 2.5 micrometers. Alternatively, in some other embodiments, they can also respond to light waves with a wider range of wavelengths, such as 0.9 micrometers to 3 micrometers. Colloidal quantum dot short-wave infrared imaging devices have the advantage of low cost, and multiple imaging devices can be set up according to the required range and number of sub-bands of light dispersion. The first imaging device 400, the second imaging device 500, and the third imaging device 600 can have the following parameters: response wavelength range at least covering: greater than or equal to 1 micrometer and less than or equal to 2.5 micrometers; size (pixels): 640 × 512; pixel size: 15 micrometers × 15 micrometers. The distances between the first imaging device 400 and the compensation mirror 300 (described later), the distances between the second imaging device 500 and the second right-angled surface of the third prism 221, and the distances between the third imaging device 600 and the right-angled surface of the fourth prism 222 on the opposite side of the first beam splitting assembly 210 are adjustable, and are generally used to focus on targets at different distances.

[0040] In one embodiment, the optical system further includes a compensation mirror 300, which is located between the first beam splitter 210 and the first imaging device 400.

[0041] The compensating mirror 300 is a cuboid flat mirror. The dimensions of any face of the compensating mirror 300, the right-angled face of the first prism 211, and the right-angled face of the second prism 212 are identical, and their transmission and reflection surfaces must be precision polished. For example, the side length and edge length of the right-angled face of the compensating mirror 300 can both be 15 mm. In different embodiments, the relative position of the compensating mirror 300 and the first beam splitter 210 is different, resulting in different light paths. The following detailed description combines two embodiments: Firstly, such as Figure 1-2 In the embodiment shown, the compensating mirror 300 is disposed relative to the first prism 211, and the surface of the compensating mirror 300 relative to the first prism 211 is parallel to the second right-angled surface of the first prism 211. The distance between the compensating mirror 300 and the first prism 211, and the distance between the second prism 212 and the third prism 221 are adjustable within a certain range, such as the distance between the compensating mirror 300 and the first prism 211 being greater than or equal to 2 mm, or it can be 3 mm.

[0042] Secondly, such as Figure 3-4 In the embodiment shown, the compensating mirror 300 is disposed relative to the second prism 212. The surface of the compensating mirror 300 relative to the second prism 212 is parallel to the right-angled surface of the second prism 212 away from the common optical path objective lens 100. The distance between the compensating mirror 300 and the second prism 212, and the distance between the first prism 211 and the third prism 221 are adjustable within a certain range, such as the distance between the compensating mirror 300 and the second prism 212 being greater than or equal to 2 mm, or 3 mm.

[0043] The converging light line from the common-path objective lens 100 is split into a first photonic waveband by the first beam-splitting component 210. In the first prism 211, the light propagates a distance equal to the side length of the first right-angled face of the prism 211. The intermediate photonic waveband continues to propagate to the second beam-splitting component 220. Regardless of whether it's a third or second photonic waveband, it will propagate through the second beam-splitting component 220 for the length of the first right-angled face of the second beam-splitting component 220, based on the first photonic waveband. This results in the first photonic waveband's propagation distance in the prism being shorter than that of the second and third photonic wavebands, negatively impacting the system's color imaging quality. Therefore, a compensation mirror 300 is added to increase the propagation distance of the first photonic waveband in the prism, ensuring that each split sub-band has almost identical imaging quality, thus guaranteeing excellent color imaging quality.

[0044] In one embodiment, the common-path objective lens 100 is a coaxial optical system of four groups and six elements. It can be an optical system entirely composed of spherical plane lenses (which can be equivalent to a sphere with an infinite radius); or it can be an optical system composed of aspherical lenses. More specifically, the common-path objective lens 100 includes a first lens 110, a second lens 120, a third lens 130, and a fourth lens 140 arranged sequentially in the direction close to the beam splitter. The optical axes of the first lens 110, second lens 120, third lens 130, and fourth lens 140 coincide, i.e., they are coaxially arranged. The first lens 110 is used at least for transmitting and focusing incident light waves from the environment; the second lens 120 and third lens 130 are used at least for chromatic aberration correction; and the fourth lens 140 is used at least for adjusting the position of the light waves transmitted by the third lens 130.

[0045] Furthermore, the second lens 120 includes a first sub-lens 121 and a second sub-lens 122, which are cemented together to form a cemented lens. The third lens 130 includes a third sub-lens 131 and a fourth sub-lens 132, which are cemented together to form a cemented lens.

[0046] The first lens 110, the second lens 120, the third lens 130, and the fourth lens 140 form four groups of six lenses arranged coaxially. The optical powers of the first lens 110, the first sub-lens 121, the second sub-lens 122, the third sub-lens 131, the fourth sub-lens 132, and the fourth lens 140 are positive and negative respectively: + + - + - -. The first lens 110, the first sub-lens 121, the second sub-lens 122, the third sub-lens 131, the fourth sub-lens 132, and the fourth lens 140 can all be spherical lenses. Any one of the first lens 110, the first sub-lens 121, the second sub-lens 122, the third sub-lens 131, the fourth sub-lens 132, and the fourth lens 140 can also be a plano-concave or plano-convex lens, that is, the plane mentioned above can be equivalent to a sphere with an infinite radius. Alternatively, only some of the lenses in the first lens 110, first sub-lens 121, second sub-lens 122, third sub-lens 131, fourth sub-lens 132, and fourth lens 140 are spherical lenses, while the other parts are aspherical lenses.

[0047] The first lens 110 is mainly used for the initial focusing of the incident light wave. The first sub-lens 121 converges the light wave, the second sub-lens 122 diverges the light wave, the third sub-lens 131 converges the light wave, and the fourth sub-lens 132 and the fourth lens 140 diverge the light wave. Through the combination of positive and negative lenses, and the design and material selection of optical surfaces and thicknesses, a comprehensive and optimized design is achieved to meet technical requirements such as focal length and to correct various aberrations. The fourth lens 140 is positioned closer to the first beam splitter 210. For example, the distance between the fourth lens 140 and the first prism 211 can be greater than or equal to 2 mm, such as 5.56 mm. If other values ​​are used, the subsequent optical spacing needs to be adjusted accordingly. It is necessary to ensure that: the sum of all air gaps behind the fourth lens 140 remains unchanged, and the distances between the compensating mirror 300 and the first imaging device 400, the distances between the second beam splitter 220 and the second imaging device 500, and the distances between the second beam splitter 220 and the third imaging device 600 are all greater than or equal to 2 mm.

[0048] The focal length of the common-path objective lens 100 can be determined according to specific technical requirements, such as 90 mm.

[0049] In a more specific embodiment, the diameters of the first lens 110, first sub-lens 121, second sub-lens 122, third sub-lens 131, fourth sub-lens 132, and fourth lens 140 may not exceed 26 mm. The parameters of the first lens 110, first sub-lens 121, second sub-lens 122, third sub-lens 131, fourth sub-lens 132, and fourth lens 140 can be set as follows. It should be understood that the following is merely an example, and those skilled in the art can adjust them according to actual needs: The incident surface of the first lens 110 is approximately planar; the radius of curvature of the exit surface of the first lens 110 is -83.95 mm; the radius of curvature of the incident surface of the first sub-lens 121 is 37.5 mm; the radius of curvature of the exit surface of the first sub-lens 121 and the incident surface of the second sub-lens 122 is -164.06 mm; the radius of curvature of the exit surface of the second sub-lens 122 is 43.85 mm; the radius of curvature of the incident surface of the third sub-lens 131 is 34.43 mm; the radius of curvature of the exit surface of the third sub-lens 131 and the incident surface of the fourth sub-lens 132 is -113.49 mm; the radius of curvature of the exit surface of the fourth sub-lens 132 is 77.95 mm; the radius of curvature of the incident surface of the fourth lens 140 is 12.367 mm; the radius of curvature of the exit surface of the fourth lens 140 is 10.362 mm.

[0050] The thickness of the first lens 110 is greater than or equal to 2.69 mm; The center thickness of the first sub-lens 121 is 3.85 mm, and the center thickness of the second sub-lens 122 is 1.8 mm. The center thickness of the third sub-lens 131 is 4.24 mm, and the center thickness of the fourth sub-lens 132 is 1.8 mm. The thickness of the fourth lens 140 is 2.57 mm.

[0051] The distance between the fourth sub-lens 132 and the fourth lens 140 is 31.48 mm.

[0052] The first lens 110 is made of H-ZK20 glass; the first sub-lens 121 is made of H-K9L glass; the second sub-lens 122 is made of H-LAK53A glass; the third sub-lens 131 is made of H-LAF4 glass; the fourth sub-lens 132 is made of H-ZF88 glass; and the fourth lens 140 is made of H-ZF88 glass.

[0053] In one embodiment, the common-path objective lens 100 further includes an aperture stop 150, which is disposed between the second lens 120 and the third lens 130.

[0054] The aperture 150 is used to constrain the diameter of the incident light, ensuring that sufficient light energy enters the optical system. In one embodiment, the distance between the second sub-lens 122 and the aperture 150 is 2.4 mm.

[0055] like Figure 5-7 The optical system field curvature / distortion design results and optical system MTF design results obtained for one embodiment of the system are shown in the figure. As can be seen from the figure, the optical system using this application has excellent imaging quality.

[0056] On the other hand, such as Figure 8 As shown, the present invention also provides a short-wave infrared color imaging method, based on any of the above-mentioned short-wave infrared color imaging optical systems, the method comprising: S1. The incident light wave in the short-wave band is subjected to two dichroic beam splits to form three sub-band light waves, which are then imaged onto three colloidal quantum dot short-wave infrared imaging devices.

[0057] S2. Obtain the display requirements and determine the type of display requirements.

[0058] The first imaging device 400, the second imaging device 500, and the third imaging device 600 are all connected to a main controller, which is connected to a display. The display can be a human-computer interaction mechanism or a separately configured receiver capable of acquiring user requests. The user can select a display mode for individual images, such as displaying only images formed by the first photon band of light in the 1-1.5 micrometer wavelength range, or only images formed by the second photon band of light in the 1.5-2 micrometer wavelength range, or only images formed by the third photon band of light in the 2-2.5 micrometer wavelength range. The user's request includes the requirement for individual display of images in a single wavelength range and the specific wavelength range to be displayed. Alternatively, users can select a color display mode. For example, images formed by the first photon band of light in the 1-1.5 micrometer wavelength range, images formed by the second photon band of light in the 1.5-2 micrometer wavelength range, and images formed by the third photon band of light in the 2-2.5 micrometer wavelength range can be superimposed and displayed. It can be understood that images in different wavelength ranges are displayed in different colors, so the user's request includes the requirement to display color images.

[0059] S3. When the display requirement is the individual display of a certain sub-band of light, acquire the target imaging device, determine whether the target imaging device is the imaging device corresponding to the single reflection beam splitting, if so, perform mirror processing based on the image signal of the target imaging device and display it, if not, perform direct display based on the image signal of the target imaging device; when the display requirement is color display, perform mirror processing on the image signal of the imaging device corresponding to the single reflection beam splitting, and display it simultaneously based on the image signals of all three imaging devices.

[0060] When the display requirement is a single display, the target imaging device is determined based on the wavelength band to be displayed in the user's requirements. For example, if the user's requirement is to display only the image formed by the second photon band light wave in the 1.5-micron to 2-micron wavelength band, then the main controller will use the second imaging device 500 corresponding to the 1.5-micron to 2-micron wavelength band as the target imaging device. Determining whether the target imaging device is an imaging device corresponding to a single-reflection beam splitting refers to determining whether the beam splitting received by the target imaging device is only reflected once.

[0061] As in Figure 1-2In the illustrated embodiment, the first photonic band light wave is a single-reflection beam splitting that is reflected once by the inclined surface of the first prism 211. If the target imaging device is the first imaging device 400, the image signal of the first imaging device 400 needs to be mirrored and transmitted to the RGB input terminal of the color display for display. The second photonic band light wave is a single-reflection beam splitting that is reflected once by the inclined surface of the third prism 221. If the target imaging device is the second imaging device 500, the image signal of the second imaging device 500 needs to be mirrored and transmitted to the RGB input terminal of the color display for display. The third photonic band light wave is not reflected. If the target imaging device is the third imaging device 600, the image signal of the third imaging device 600 is directly transmitted to the RGB input terminal of the color display for display.

[0062] When the display requirement is color display, the image signal of the first imaging device 400 is mirrored, the image signal of the second imaging device 500 is mirrored, and the processed image and the image signal of the third imaging device 600 are simultaneously transmitted to the RGB input terminal of the color display for display of different colors, thereby realizing the display of color images on the display and realizing the scene target in short-wave infrared multi-band common optical path color imaging.

[0063] Or in Figure 3-4 In the illustrated embodiment, the first photonic band light wave is not reflected. If the target imaging device is the first imaging device 400, the image signal of the first imaging device 400 is directly transmitted to the RGB input terminal of the color display for display. The second photonic band light wave is a double-reflected beam split by being reflected once by the inclined surface of the first prism 211 and once by the inclined surface of the third prism 221. If the target imaging device is the second imaging device 500, the image signal of the first imaging device 400 is directly transmitted to the RGB input terminal of the color display for display. The third photonic band light wave is a single-reflected beam split by being reflected once by the inclined surface of the first prism 211. If the target imaging device is the third imaging device 600, the image signal of the third imaging device 600 needs to be mirrored and transmitted to the RGB input terminal of the color display for display.

[0064] When the display requirement is color display, the image signal of the third imaging device 600 is mirrored, and the processed image, along with the image signals of the first imaging device 400 and the second imaging device 500, are simultaneously transmitted to the RGB input terminal of the color display for display of different colors, thereby realizing the display of color images on the display and achieving color imaging of the scene target in short-wave infrared multi-band common optical path.

[0065] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions made by those skilled in the art within the scope of the technology disclosed in the present invention, such as scaling the system or other simple and easy changes or substitutions, should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A short-wave infrared color imaging optical system, characterized in that, include: Common-path objective lens, beam splitter assembly, and three imaging devices; The common-path objective lens is used to receive and converge the incident light wave, and to output the converged light wave to the beam splitter. The beam splitter is used to perform dichroic beam splitting on the converged light wave, resulting in three sub-band light waves, which are then imaged onto the three imaging devices respectively. The wavelength ranges of the three sub-bands of light are different; The three imaging devices include a first imaging device, a second imaging device, and a third imaging device; The beam splitting component includes a first beam splitting component and a second beam splitting component; A compensation mirror located between the first beam-splitting component and the first imaging device; The first beam splitter is used to perform dichroic beam splitting on the incident light wave into a first photonic band light wave and an intermediate photonic band light wave. The first photonic band light wave is imaged on a first imaging device, and the intermediate photonic band light wave is transmitted to a second beam splitter. The second beam splitter is used to split the intermediate photonic band light wave into a second photonic band light wave and a third photonic band light wave. The second photonic band light wave is imaged on a second imaging device, and the third photonic band light wave is imaged on a third imaging device. The first beam splitting component includes a first prism and a second prism. The first prism is located between the second prism and the common optical path objective lens. The surface of the first prism relative to the second prism forms a 45-degree angle with the optical axis of the common optical path objective lens. A first dichroic film is provided on the surfaces of the first prism and the second prism. The first prism and the second prism are glued together or have a preset air gap between them. The second beam splitting component includes a third prism and a fourth prism. The third prism is located between the fourth prism and the first beam splitting component, and the surface of the third prism relative to the fourth prism forms a 45-degree angle with the optical axis of the common optical path objective lens. A second dichroic film is provided on the surfaces of the third prism and the fourth prism. The third prism and the fourth prism are glued together or have a preset air gap between them. The first imaging device, the second imaging device, and the third imaging device are all colloidal quantum dot short-wave infrared imaging devices, with a response wavelength range covering at least 1 micrometer to 2.5 micrometers, and located on the mirror-image focal plane of the common optical path object; The common-path objective lens is a coaxial optical system in the form of four groups of six elements, including: a first lens, a second lens, a third lens and a fourth lens arranged coaxially in sequence in the direction close to the beam splitter.

2. The short-wave infrared color imaging optical system according to claim 1, characterized in that, A first dichroic film is disposed on the surface of the first prism opposite to the surface of the second prism. The first dichroic film is used to perform a first dichroic split on the incident light wave: reflecting to form a first photonic waveband light wave and transmitting to form an intermediate photonic waveband light wave. A second dichroic film is disposed on the surface of the third prism opposite to the surface of the fourth prism. The second dichroic film is used to perform a second dichroic split on the incident light wave: reflecting to form a second photonic waveband light wave and transmitting to form a third photonic waveband light wave. Alternatively, a first dichroic film is disposed on the surface of the first prism opposite to the surface of the second prism. The first dichroic film is used to perform a first dichroic split on the incident light wave: reflecting to form the intermediate photonic waveband and transmitting to form the first photonic waveband. A second dichroic film is disposed on the surface of the third prism opposite to the surface of the fourth prism. The second dichroic film is used to perform a second dichroic split on the incident light wave: reflecting to form the second photonic waveband and transmitting to form the third photonic waveband.

3. The short-wave infrared color imaging optical system according to claim 1, characterized in that, The wavelength ranges of the first, second, and third photonic band light waves are all within the shortwave infrared band, and the wavelength ranges of the first, second, and third photonic band light waves do not overlap.

4. The short-wave infrared color imaging optical system according to claim 1, characterized in that, The first lens is used at least for transmitting and focusing the incident light wave; the second lens and the third lens are used at least for chromatic aberration correction of the light wave transmitted by the first lens; and the fourth lens is used at least for adjusting the position of the light wave transmitted by the third lens. The first lens, the second lens, the third lens, and the fourth lens are all spherical lenses; Alternatively, at least one of the first lens, the second lens, the third lens, and the fourth lens may be an aspherical lens.

5. The short-wave infrared color imaging optical system according to claim 4, characterized in that, The common-path objective lens also includes an aperture stop, which is disposed between the second lens and the third lens.

6. A short-wave infrared color imaging method, based on the short-wave infrared color imaging optical system according to any one of claims 1-5, characterized in that, The method includes: The incident light wave in the short-wave band is split into three sub-bands by two dichroic beam splits, and then imaged onto three colloidal quantum dot short-wave infrared imaging devices respectively. Obtain the display requirements and determine the type of display requirements; When the display requirement is a single display of a certain sub-band, the target imaging device is acquired, and it is determined whether the target imaging device is an imaging device corresponding to single reflection beam splitting; if so, the image signal of the target imaging device is mirrored and displayed; if not, the image signal of the target imaging device is displayed directly. When the display requirement is color display, the image signal of the imaging device corresponding to the single reflection beam split is mirrored, and then the image signals of all three imaging devices are displayed simultaneously.

Images