Short-wave infrared color imaging method and optical system

Abstract

The invention discloses a short-wave infrared color imaging method and an optical system, relates to the technical field of photoelectric imaging, and mainly receives, converges and splits short-wave infrared light waves to form three sub-band light waves which are respectively focused and imaged to three colloidal quantum dot short-wave infrared imaging devices. When color imaging is needed, light splitting is carried out twice to obtain three sub-band image information, and the three sub-band image information is transmitted to the input end of a color display, so that short-wave infrared multi-band common-optical-path color imaging is realized, and the problem that color imaging cannot be realized is solved. According to the main technical scheme, the short-wave infrared color imaging optical system comprises a common-path objective lens, a light splitting assembly and three imaging devices; the common-path objective lens is used for receiving and converging incident light waves and then emitting the incident light waves to the light splitting assembly, and the light splitting assembly is used for carrying out dichroic light splitting on the converged light waves to form three sub-band light waves which are respectively imaged on the three imaging devices; and different sub-bands have different wavelength ranges of light waves. The method is mainly used for short-wave infrared color imaging.

Description

Technical Field

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

[0002] The use of short-wave infrared bands to detect and image environmental targets has gradually become a new practical demand direction. The detection and imaging technology of the short-wave infrared band mainly uses the light energy in the 1 micron to 3 micron band (or part of the band) for receiving, detecting and imaging. The existing detection and imaging methods of the short-wave infrared band are based on indium gallium arsenide (InGaAs) short-wave infrared detectors, but due to their high prices, they generally only use a single-channel optical system and a single short-wave infrared detector to receive, detect and image the incident light energy, and can only obtain black and white (or monochrome) grayscale image information of a single band. The spectral information and light energy of the short-wave band are not fully utilized, and the use of only grayscale information is not conducive to distinguishing different types of targets in the use environment, resulting in unsatisfactory target detection, observation and recognition effects. 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 converges and splits short-wave infrared light waves, focuses them on different imaging devices respectively, and obtains color imaging through image fusion display.

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

[0005] Wherein, the light splitting component includes a first light splitting component and a second light splitting component; The three imaging devices include a first imaging device, a second imaging device and a third imaging device; The first spectroscopic component is used to perform dichroic spectrometry on the incident light wave to form a first spectroscopic sub-band light wave and an intermediate spectroscopic sub-band light wave. The first spectroscopic sub-band light wave is imaged on the first imaging device, and the intermediate spectroscopic sub-band light wave is transmitted to the second spectroscopic component. The second spectroscopic component is used to split the intermediate spectroscopic sub-band light wave into a second spectroscopic sub-band light wave and a third spectroscopic sub-band light wave. The second spectroscopic sub-band light wave is imaged on the second imaging device, and the third spectroscopic sub-band light wave is imaged on the third imaging device.

[0006] The first light splitting component includes a first prism and a second prism, the first prism is located between the second prism and the common light path objective lens, and the surface of the first prism relative to the second prism forms an angle of 45 degrees with the optical axis of the common light path objective lens; The second light splitting component includes a third prism and a fourth prism, the third prism is located between the fourth prism and the first light splitting component, and the surface of the third prism relative to the fourth prism forms an angle of 45 degrees with the optical axis of the common light path objective lens; A first dichroic film is arranged on the surface of the first prism opposite to the second prism, and the first dichroic film is used to perform a first splitting of the incident light wave: reflecting to form a light wave of a first sub-band, and transmitting to form a light wave of an intermediate sub-band; a second dichroic film is arranged on the surface of the third prism opposite to the fourth prism, and the second dichroic film is used to perform a second splitting of the incident light wave: reflecting to form a light wave of a second sub-band, and transmitting to form a light wave of a third sub-band; Alternatively, a first dichroic film is arranged on the surface of the first prism opposite to the second prism, and the first dichroic film is used to perform a first dichroic separation on the incident light wave: reflecting to form an intermediate photon-band light wave, and transmitting to form a first photon-band light wave; a second dichroic film is arranged on the surface of the third prism opposite to the fourth prism, and the second dichroic film is used to perform a second dichroic separation on the incident light wave: reflecting to form a second photon-band light wave, and transmitting to form a third photon-band light wave.

[0007] 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 is preset between the first prism and the second prism, and an air gap is preset between the third prism and the fourth prism.

[0008] Among them, the wavelength range of the first sub-photon band, the wavelength range of the second sub-photon band, and the wavelength range of the third sub-photon band are within the short-wave infrared band, and the wavelength range of the first sub-photon band, the wavelength range of the second sub-photon band, and the wavelength range of the light waves of the third sub-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 micron to 2.5 microns, and are located in the focal plane of the common optical path object image.

[0010] The optical system also includes: The compensation mirror is located between the first light splitting component and the first imaging device.

[0011] The common light path objective lens is a coaxial optical system in the form of four groups of six lenses, including a first lens, a second lens, a third lens and a fourth lens coaxially arranged in sequence in a direction close to the light splitting component; The first lens is at least used for transmitting and focusing the converging light wave, the second lens and the third lens are at least used for correcting the chromatic aberration of the light wave transmitted by the first lens, and the fourth lens is at least used 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 is an aspherical lens.

[0012] The common light path objective lens further includes an aperture, and the aperture is arranged between the second lens and the third lens.

[0013] On the other hand, the present invention further provides a short-wave infrared color imaging method, based on any of the above short-wave infrared color imaging optical systems, the method comprising: The incident light wave in the short-wave band is split into two dichroic beams to form light waves in three sub-bands, which are imaged on three colloidal quantum dot short-wave infrared imaging devices respectively; Obtain display requirements and determine the type of display requirements; When the display requirement is to display a certain sub-band separately, the target imaging is obtained, and it is determined whether the target imaging device is an imaging device corresponding to single reflection spectroscopy; 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 directly displayed; When the display requirement is color display, the image signal of the imaging device corresponding to the single reflection splitting 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 by the present invention receive the short-wave infrared incident light wave from the environmental target by the common optical path objective lens and focus it, and then transmit it to the light splitting component, after the light splitting component performs dichroic light splitting, it is divided into at least two sub-light waves of different wavelengths, and is focused and imaged on the corresponding three imaging devices respectively, and one of the sub-band light wave images can be displayed separately to obtain the image corresponding to the single sub-band light wave; any two of the sub-band light wave images can also be combined and displayed to obtain the corresponding image of the double sub-band light wave; of course, the image information in the three imaging devices can also be output to the color display at the same time, so as to obtain the color imaging of the short-wave infrared band of the environmental target, that is, to realize short-wave infrared multi-band color imaging. The present invention can not only better identify the target characteristics (especially the short-wave infrared spectral characteristics), but also has small size, light weight, low cost, compact structure, and convenient use. It is particularly suitable for the actual market demand of short-wave band imaging instruments and has good beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic structural diagram of a first short-wave infrared color imaging optical system provided by an embodiment of the present invention; Figure 2 A schematic structural diagram of a second short-wave infrared color imaging optical system provided by an embodiment of the present invention; Figure 3 A schematic structural diagram of a third short-wave infrared color imaging optical system provided by an embodiment of the present invention; Figure 4 A schematic structural diagram of a fourth short-wave infrared color imaging optical system provided by an embodiment of the present invention; Figure 5 A schematic diagram of a simulation result of field curvature of a short-wave infrared color imaging optical system provided by an embodiment of the present invention; Figure 6 A schematic diagram of simulation of distortion results of a short-wave infrared color imaging optical system provided by an embodiment of the present invention; Figure 7 A schematic diagram of a simulation of the MTF results of a short-wave infrared color imaging optical system provided by an embodiment of the present invention; Figure 8 A flow chart of a short-wave infrared color imaging method provided by an embodiment of the present invention; Among them, the common light 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 component 200, the first beam splitter component 210, the first prism 211, the second prism 212, the second beam splitter component 220, the third prism 221, the fourth prism 222, the compensation mirror 300, the first imaging device 400, the second imaging device 500, and the third imaging device 600. DETAILED DESCRIPTION

[0016] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation method, structure, characteristics and effects of a short-wave infrared color imaging optical system proposed by the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0017] like Figure 1 , Figure 2 , Figure 3 , Figure 4 As shown, an embodiment of the present invention provides a short-wave infrared color imaging optical system, comprising: Common optical path objective lens 100, light splitting component 200 and three imaging devices; The common optical path objective lens 100 is used to receive the incident light wave and converge it, and emit the converged light wave to the light splitting component 200. The light splitting component 200 is used for dichroic light splitting, and the converged light wave is divided into three sub-band light waves, which are then imaged on three imaging devices respectively; The wavelength ranges of the three sub-band light waves are different and do not overlap with each other.

[0018] The common light path objective lens 100 is used to receive and converge short-wave infrared incident light waves from environmental targets to complete focused imaging. In addition, through the optical design of the common light path objective lens 100, the common light path objective lens 100 can also realize the optical system aberration correction function such as spherical aberration, coma, field curvature, astigmatism, distortion, chromatic aberration, etc. of the light waves, so as to achieve excellent imaging quality of the system. The converged light waves will be emitted to the spectroscopic component 200. The spectroscopic component 200 uses a dichroic spectroscopic film (the coating surface is at a 45-degree angle to the optical axis of the common light path objective lens) designed and plated with a film system that meets technical requirements to split the incident light waves, thereby forming a reflected sub-band light wave and a transmitted sub-band light wave, which can realize two dichroic splitting of the short-wave infrared light wave, and can be divided into three sub-band light waves. The different sub-band light waves emitted by the spectroscopic component 200 will be imaged on the corresponding imaging devices respectively. After the photoelectric conversion of the imaging devices, the corresponding image information of each sub-band is obtained, so that the sub-band images can be displayed separately, or the images of each channel can be combined differently, and the corresponding image information of two or three sub-band light waves can be output to the color display at the same time, so as to realize the monochrome or color display of the images corresponding to different sub-band light waves, especially the display of short-wave infrared band color images.

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

[0020] It is worth noting that the present application only sets a single common light path objective lens 100, that is, the light splitting component 200 and multiple imaging devices share one imaging objective lens, and the design uses a compensating mirror to ensure that the focal length value, distortion deviation and other design parameters of each sub-band after light splitting are more consistent, which can maximize the image quality and observation effect of multi-band color imaging. The common light path objective lens 100 uses the most commonly used colorless optical glass material, with stable performance, low cost and good quality. The specific composition of the common light path objective lens 100 will be described in more specific implementations later.

[0021] The short-wave infrared color imaging method and optical system proposed by the present invention receive the short-wave infrared incident light wave from the environmental target by the common optical path objective lens and focus it, and then transmit it to the light splitting component, after the light splitting component performs dichroic light splitting, it is divided into at least two sub-light waves of different wavelengths, and is focused and imaged on the corresponding three imaging devices respectively, and one of the sub-band light wave images can be displayed separately to obtain the image corresponding to the single sub-band light wave; any two of the sub-band light wave images can also be combined and displayed to obtain the corresponding image of the double sub-band light wave; of course, the image information in the three imaging devices can also be output to the color display at the same time, so as to obtain the color imaging of the short-wave infrared band of the environmental target, that is, to realize short-wave infrared multi-band color imaging. The present invention can not only better identify the target characteristics (especially the short-wave infrared spectral characteristics), but also has small size, light weight, low cost, compact structure, and convenient use. It is particularly suitable for the actual market demand of short-wave band imaging instruments and has good beneficial effects.

[0022] As mentioned above, after the common optical path objective lens 100 emits a convergent light wave line through the spectroscopic component 200, the number of the spectroscopic optical paths can be multiple, such as two or three. In the following implementation, the spectroscopic component 200 is used to form three beams of spectroscopic sub-bands as an example. Among them, the sub-bands of the three-beam spectroscopic light can be selected as needed, but it is necessary to satisfy that the wavelength range of the first sub-band light wave, the wavelength range of the second sub-band light wave, and the wavelength range of the third sub-band light wave are within the short-wave infrared band range, and the wavelength range of the first sub-band light wave, the wavelength range of the second sub-band light wave, and the wavelength range of the third sub-band light wave are different, can be selected as needed, and do not overlap with each other. For example, it can be: the wavelength range of the first sub-band light wave is greater than or equal to 1 micron, and less than 1.5 microns; the wavelength range of the second sub-band light wave is greater than or equal to 1.5 microns, and less than 2 microns; the wavelength range of the third sub-band light wave is greater than or equal to 2 microns, and less than or equal to 2.5 microns. Alternatively, the wavelength range of the light wave of the first sub-band may be greater than or equal to 1 micron and less than 1.2 microns; the wavelength range of the light wave of the second sub-band may be greater than or equal to 1.2 microns and less than 2.3 microns; the wavelength range of the light wave of the third sub-band may be greater than or equal to 2.3 microns and less than or equal to 2.5 microns. Alternatively, other settings may be used, which are not listed one by one in this application. The spectroscopic component 200 includes a first spectroscopic component 210 and a second spectroscopic 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 spectroscopic component 210 is used to perform dichroic spectrometry on the incident light wave, dividing it into a first spectroscopic sub-band light wave and an intermediate spectroscopic sub-band light wave. The first spectroscopic sub-band range is imaged on the first imaging device 400, and the intermediate spectroscopic sub-band light wave is emitted to the second spectroscopic component 220. The second spectroscopic component 220 is used to divide the intermediate spectroscopic sub-band range into a second spectroscopic sub-band light wave and a third spectroscopic sub-band light wave. The second spectroscopic sub-band light wave is imaged on the second imaging device 500, and the third spectroscopic sub-band light wave is imaged on the third imaging device 600.

[0023] The first light splitting component 210 can be disposed at various positions of the second light splitting component 220. For example, in one embodiment, Figure 1-2As shown, the first beam splitter component 210 may be located between the second beam splitter component 220 and the common light path objective lens 100, that is, the first beam splitter component 210 and the second beam splitter component 220 are arranged in sequence on the outgoing light path of the convergent light wave of the common light path objective lens 100. In other words, the first beam splitter component 210 and the second beam splitter component 220 are arranged in sequence on the light outgoing side of the common light path objective lens 100, along the optical axis of the common light path objective lens 100 in a direction away from the common light path objective lens 100. The first imaging device 400 is located on the path of the first beam splitter sub-band light wave reflected by the first beam splitter component 210, the second imaging device 500 is located on the path of the second beam splitter sub-band light wave reflected by the second beam splitter component 220, and the third imaging device 600 is located on the path of the third beam splitter sub-band light wave transmitted by the second beam splitter component 220.

[0024] The short-wave infrared light waves from the environmental target are received and focused by the common optical path objective lens 100, and then transmitted to the first spectroscopic component 210, and undergo dichroic spectroscopy through the first spectroscopic component 210 to become two beams of light waves, which may be perpendicular to each other, wherein the first spectroscopic sub-band light waves are reflected by the first spectroscopic component 210 and focused and imaged on the first imaging device 400; the second spectroscopic sub-band light waves are transmitted through the first spectroscopic component 210, and undergo dichroic spectroscopy again through the second spectroscopic component 220 to become two beams of light waves perpendicular to each other, wherein the second spectroscopic sub-band light waves are reflected by the second spectroscopic component 220 and focused and imaged on the second imaging device 500, and the third spectroscopic sub-band light waves are transmitted through the second spectroscopic component 220 and focused and imaged on the third imaging device 600.

[0025] Or, in another embodiment, it can be as follows Figure 3-4 As shown, the first beam splitter component 210 may be located on the outgoing light path of the convergent light wave of the common light path objective lens 100, and the first beam splitter component 210 and the second beam splitter component 220 are arranged in a direction perpendicular to the optical axis of the common light path objective lens 100. The first imaging device 400 is located on the path of the first beam splitter waveband light wave projected by the first beam splitter component 210, the second imaging device 500 is located on the path of the second beam splitter waveband light wave reflected by the second beam splitter component 220, and the third imaging device 600 is located on the path of the third beam splitter waveband light wave transmitted by the second beam splitter component 220.

[0026] The short-wave infrared light waves from the environmental target are received and focused by the common optical path objective lens 100, and then transmitted to the first spectroscopic component 210, and undergo dichroic spectroscopy through the first spectroscopic component 210 to become two beams of light waves, which may be perpendicular to each other, wherein the first spectroscopic sub-band light waves are transmitted by the first spectroscopic component 210 and focused and imaged on the first imaging device 400; the second spectroscopic sub-band light waves are reflected by the first spectroscopic component 210, and undergo dichroic spectroscopy again through the second spectroscopic component 220 to become two beams of light waves perpendicular to each other, wherein the second spectroscopic sub-band light waves are reflected by the second spectroscopic component 220 and focused and imaged on the second imaging device 500, and the third spectroscopic sub-band light waves are transmitted by the second spectroscopic component 220 and focused and imaged on the third imaging device 600.

[0027] Taking the wavelength range of the light wave of the first sub-photon band as an example, which is greater than or equal to 1 micron and less than 1.5 microns; the wavelength range of the light wave of the second sub-photon band as an example, which is greater than or equal to 1.5 microns and less than 2 microns; the wavelength range of the light wave of the third sub-photon band as an example, after the action of the optical system: three short-wave infrared sub-light waves of 1 micron to 1.5 microns, 1.5 microns to 2 microns, and 2 microns to 2.5 microns are focused and imaged on three imaging devices respectively, and short-wave infrared multi-band common optical path color imaging image information can be obtained. The setting of the three sub-light bands makes full use of the incident light energy from the short-wave band of the target scene, that is, makes full use of the light energy and spectral information of the three short-wave bands of 1 micron to 1.5 microns, 1.5 microns to 2 microns, and 2 microns to 2.5 microns.

[0028] In a more specific implementation manner, Figure 1-4 As shown, the first light splitting component 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 light path objective lens 100, and the surface of the first prism 211 relative to the second prism 212 forms an angle of 45 degrees with the optical axis of the common light path objective lens 100. The second light splitting component 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 light splitting component 210, and the surface of the third prism 221 relative to the fourth prism 222 forms an angle of 45 degrees with the optical axis of the common light path objective lens 100.

[0029] In order to achieve transmission and reflection of incident light and achieve light splitting, a dichroic film is provided on the first prism 211 and the third prism 221. Figure 1-2 The embodiment shown, and Figure 3-4 In the embodiment shown, the color separation films disposed on the first prism 211 and the third prism 221 are different. The following will combine the two embodiments to provide examples for description: First, if Figure 1-2As shown, a first dichroic film is disposed on the surface of the first prism 211 opposite to the second prism 212, and performs a first splitting of the incident light wave: the first splitting light wave is formed by the reflection of the first dichroic film, and the intermediate splitting light wave is formed by the transmission of the first dichroic film. A second dichroic film is disposed on the surface of the third prism 221 opposite to the fourth prism 222, and performs a second splitting of the incident light wave: the second splitting light wave is formed by the reflection of the second dichroic film, and the third splitting light wave is formed by the transmission of the second dichroic film.

[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, which is intended to ensure that light waves of different sub-bands can have the same imaging quality. In other words, it is to ensure that the cumulative propagation lengths of light waves imaged on different imaging devices in the prism or compensation mirror are consistent. 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 is opposite to the common light path objective lens 100 and is perpendicular to the optical axis of the common light 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 is opposite to the second prism 212 and is perpendicular to the optical axis of the common light path objective lens 100. The inclined surface of the third prism 221 is parallel to the inclined surface of the fourth prism 222. The center of the inclined surface of the first prism 211, the center of the inclined surface of the second prism 212, the center of the inclined surface of the third prism 221, and the center of the inclined surface of the fourth prism 222 all intersect with the optical axis of the common optical path objective lens 100. The first dichroic film is coated on the inclined surface of the first prism 211, and the first dichroic film is designed to be a dichroic film with high reflection of 1 micron to 1.5 microns and high transmission of light waves of 1.5 microns to 2.5 microns. The second dichroic film is coated on the inclined surface of the third prism 221, and the second dichroic film is designed to be a dichroic film with high reflection of 1.5 microns to 2 microns and high transmission of light waves of 2 microns to 2.5 microns.

[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 by the compensation mirror, and is located at the image-side focal plane of the common light 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 light path objective lens 100. The third imaging device 600 is opposite to the right-angled surface of the fourth prism 222 away from the common light 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 light path objective lens 100.

[0032] During 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, that is, the second right-angled surface of the first prism 211 and the second right-angled surface of the third prism 221 are arranged in opposite directions. Figure 2 As shown, the inclined surface of the first prism 211 and the inclined surface of the third prism 221 are parallel to each other, that is, the second right-angled surface of the first prism 211 and the second right-angled surface of the third prism 221 are arranged in the same direction. Alternatively, there can be other various arrangements, that is, it can be understood that the first light splitting component 210 and the second light splitting component 220 can be rotated to any position with the optical axis of the common optical path objective lens 100 as the axis while ensuring that the main cross-sections of the two are the same, and are not limited to the positions shown in the figure, and the first imaging device 400 and the second imaging device 500 can be adaptively adjusted to their positions.

[0033] Second, if Figure 3-4 As shown, a first dichroic film is arranged on the surface of the first prism 211 opposite to the second prism 212, and the first dichroic film is used to perform a first dichroic separation on the incident light wave: reflecting to form an intermediate sub-band light wave, and transmitting to form a first sub-band light wave. A second dichroic film is arranged on the surface of the third prism 221 opposite to the fourth prism 222, and the second dichroic film is used to perform a second dichroic separation on the incident light wave: reflecting to form a second sub-band light wave, and transmitting to form a third sub-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, which is intended to ensure that light waves of different sub-bands can have the same imaging quality. In other words, it is to ensure that the cumulative propagation lengths of light waves imaged on different imaging devices in the prism or compensation mirror are consistent. 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 is opposite to the common light path objective lens 100 and is perpendicular to the optical axis of the common light 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 is opposite to the first prism 211 and is parallel to the optical axis of the common light path objective lens 100. The inclined surface of the third prism 221 is parallel to the inclined surface of the fourth prism 222. The center of the first prism 211 and the center of the second prism 212 intersect with the optical axis of the common optical path objective lens 100, and the line between the center of the third prism 221 and the center of the fourth prism 222 and the center of the first prism 211 is perpendicular to the optical axis of the optical path objective lens 100. The first dichroic film is coated on the inclined surface of the first prism 211, and the first dichroic film is designed to be a dichroic film with high transmission of 1 micron to 1.5 microns and high reflection of 1.5 microns to 2.5 microns. The second dichroic film is coated on the inclined surface of the third prism 221, and the second dichroic film is designed to be a dichroic film with high reflection of 1.5 microns to 2 microns and high transmission of 2 microns to 2.5 microns.

[0035] During 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, that is, the first right-angled surface of the first prism 211 and the second right-angled surface of the third prism 221 are arranged in the same direction. Figure 4 As shown, the inclined surface of the first prism 211 and the inclined surface of the third prism 221 are parallel to each other, that is, 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 many other arrangements, that is, it can be understood that the first light splitting component 210 and the second light splitting component 220 can be rotated to any position with the direction perpendicular to the optical axis of the common light path objective lens 100 as the axis while ensuring that the main cross-sections of the two are the same, and are not limited to the positions shown in the figure, and the first imaging device 400 and the second imaging device 500 can be adaptively adjusted.

[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 surfaces of the first prism 211, the second prism 212, the third prism 221 and the fourth prism 222 are determined according to specific technical requirements for use. The same is true for the side 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, and the third prism 221 and the fourth prism 222 can be various, such as the first prism 211 and the second prism 212 are glued together, and the third prism 221 and the fourth prism 222 are glued together to form two glued prisms, which can ensure that the relative positions of the first prism 211 and the second prism 212, and the third prism 221 and the fourth prism 222 are stable, facilitate installation and adjustment, and reduce 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 gap may be maintained by a gasket, but it is understood that the gap is a tiny gap and cannot be set too large to ensure the imaging quality. For example, the width of the gap 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, and the response wavelength range covers 1 micron to 2.5 microns. It can be understood that coverage means that it can at least respond to light waves with a wavelength of 1 micron to 2.5 microns, or, in some other embodiments, it can also respond to light waves with a wider range of wavelengths, such as responding to light waves with a wavelength of 0.9 microns to 3 microns. Colloidal quantum dot short-wave infrared imaging devices have the advantage of low cost, and multiple imaging devices can be set according to the sub-band range and number of the required split light. The first imaging device 400, the second imaging device 500 and the third imaging device 600 can have the following parameters: the response band range at least covers: greater than or equal to 1 micron, and less than or equal to 2.5 microns; specifications (pixels): 640×512; pixel size: 15 microns×15 microns. The distance between the first imaging device 400 and the compensation mirror 300 described later, the distance between the second imaging device 500 and the second right-angle surface of the third prism 221, and the distance between the third imaging device 600 and the right-angle surface of the fourth prism 222 on the side opposite to the first splitter component 210 are adjustable and are generally used to focus on targets at different distances.

[0040] In one implementation, the optical system further includes: a compensation mirror 300 , and the compensation mirror 300 is located between the first light splitting component 210 and the first imaging device 400 .

[0041] The compensating mirror 300 is a cubic flat mirror. Any surface of the compensating mirror 300, the right-angle surface of the first prism 211, and the right-angle surface of the second prism 212 have the same specifications and dimensions, and the transmission surface, reflection surface and other surfaces thereof need to be precisely polished. For example, the side length and edge length of the right-angle surface of the compensating mirror 300 can be 15 mm. In different embodiments, the relative position of the compensating mirror 300 and the first light splitting component 210 is different, and then the optical path of the light is different. The following is a detailed description in combination with two embodiments: First, if Figure 1-2 In the illustrated embodiment, the compensation mirror 300 is arranged relative to the first prism 211, and the surface of the compensation mirror 300 relative to the first prism 211 is parallel to the second right-angled surface of the first prism 211. The spacing between the compensation mirror 300 and the first prism 211, and the spacing between the second prism 212 and the third prism 221 are adjustable within a certain range, such as the spacing between the compensation mirror 300 and the first prism 211 is greater than or equal to 2 mm, such as 3 mm.

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

[0043] The convergent light wave line of the common optical path objective lens 100 is separated by the first light splitting component 210 to produce the first sub-band light wave. The light propagation distance in the first prism 211 is the side length of the first right-angled surface of the first prism 211, and the intermediate sub-band light wave will continue to be transmitted to the second light splitting component 220. Whether it is the third sub-band light wave or the second sub-band light wave, it will be propagated in the second light splitting component 220 on the basis of the first sub-band light wave, and then propagated by the side length of the first right-angled surface of the second light splitting component 220. This will cause the propagation distance of the first sub-band light wave in the prism to be shorter than that of the second sub-band light wave and the third sub-band light wave, and have an adverse effect on the color imaging quality of the system. Therefore, the compensation mirror 300 is added to increase the propagation distance of the first sub-band light wave in the prism, and ensure that each sub-band light wave path after the light splitting has almost the same imaging quality, thereby ensuring excellent color imaging quality.

[0044] In one embodiment, the common light path objective lens 100 is a coaxial optical system in the form of four groups of six lenses, which can be: an optical system composed entirely of spherical plane lenses (which can be equivalent to a spherical surface with infinite radius); or an optical system composed of aspherical lenses. More specifically, the common light path objective lens 100 includes a first lens 110, a second lens 120, a third lens 130, and a fourth lens 140 arranged in sequence in a direction close to the light splitting component, and the optical axes of the first lens 110, the second lens 120, the third lens 130, and the fourth lens 140 coincide, that is, they are arranged coaxially. The first lens 110 is at least used to transmit and focus the incident light waves in the environment, the second lens 120 and the third lens 130 are at least used for chromatic aberration correction, and the fourth lens 140 is at least used to adjust 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 glued together to form a glued lens. The third lens 130 includes a third sub-lens 131 and a fourth sub-lens 132, which are glued together to form a glued lens.

[0046] The first lens 110, the second lens 120, the third lens 130 and the fourth lens 140 form a coaxially arranged 4 groups of 6 lenses, and the positive and negative 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: + + - + - -. 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, wherein 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 infinite radius. Alternatively, only some 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 spherical lenses, while the other parts are aspherical lenses.

[0047] The first lens 110 is mainly used for the preliminary focusing of the incident light wave. The first sub-lens 121 converges the light wave, the second sub-lens 122 is used for the divergence of the light wave, the third sub-lens 131 is used for converging the light wave, and the fourth sub-lens 132 and the fourth lens 140 are used for the divergence of the light wave. Through the combination of positive and negative lenses, as well as the design of the optical surface and thickness and the selection of materials, the technical requirements such as focal length and the comprehensive optimization design for correcting various aberrations are realized. The fourth lens 140 is arranged closer to the first light splitting component 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 taken, the optical intervals behind it need to be adjusted accordingly. It is necessary to ensure that: the sum of all air intervals behind the fourth lens 140 remains unchanged, and the distance between the compensation mirror 300 and the first imaging device 400, the distance between the second light splitting component 220 and the second imaging device 500, and the distance between the second light splitting component 220 and the third imaging device 600 are all greater than or equal to 2 mm.

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

[0049] In a more specific implementation, the diameters 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 may be no greater than 26 mm. The parameters 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 may be set according to the following parameters. It can be understood that the following is only an example, and those skilled in the art may adjust according to actual needs: The incident surface of the first lens 110 can approach a plane; the curvature radius of the exit surface of the first lens 110 is -83.95 mm; the curvature radius of the incident surface of the first sub-lens 121 is 37.5 mm; the curvature radius of the exit surface of the first sub-lens 121 and the incident surface of the second sub-lens 122 are -164.06 mm; the curvature radius of the exit surface of the second sub-lens 122 is 43.85 mm; the curvature radius of the incident surface of the third sub-lens 131 is 34.43 mm; the curvature radius 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 curvature radius of the exit surface of the fourth sub-lens 132 is 77.95 mm; the curvature radius of the incident surface of the fourth lens 140 is 12.367 mm; the curvature radius 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 implementation, the common light path objective lens 100 further includes an aperture 150 , and the aperture 150 is disposed between the second lens 120 and the third lens 130 .

[0054] The aperture 150 is used to restrict the aperture of the incident light to ensure 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 field curvature / distortion design results of the optical system and the MTF design results of the optical system obtained by adopting an implementation method of the present system. It can be seen from the figure that the optical system adopting the present application has excellent imaging quality.

[0056] On the other hand, Figure 8 As shown, the present invention also provides a short-wave infrared color imaging method, based on any of the above short-wave infrared color imaging optical systems, the method comprises: S1. Perform two dichroic splittings on the incident light wave in the short-wave band to form light waves in three sub-bands, and image them on three colloidal quantum dot short-wave infrared imaging devices respectively.

[0057] S2. Obtain 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 the main controller, and the main controller is connected to the display. The display can be a human-computer interaction mechanism, or a receiver that can obtain user needs can be set separately. The user can select the display mode as a separate display, such as only displaying the image formed by the first sub-photon band light wave of the 1 micron ~ 1.5 micron band, or only displaying the image formed by the second sub-photon band light wave of the 1.5 micron ~ 2 micron band, or only displaying the image formed by the third sub-photon band light wave of the 2 micron ~ 2.5 micron band. The user's requirements include the separate display requirements of the image of a single band and the band to be displayed. Alternatively, the user can select the display mode as color display, such as superimposing and displaying the image formed by the first sub-photon band light wave in the 1 micron ~ 1.5 micron band, the image formed by the second sub-photon band light wave in the 1.5 micron ~ 2 micron band, and the image formed by the third sub-photon band light wave in the 2 micron ~ 2.5 micron band. It can be understood that images of different bands are displayed in different colors, so the user's requirements include the demand for color image display.

[0059] S3. When the display requirement is the separate display of a certain sub-band light wave, the target imaging device is obtained to determine whether the target imaging device is an imaging device corresponding to the single reflection spectroscopy. If so, mirror processing is performed according to the image signal of the target imaging device and display is performed. If not, direct display is performed according to the image signal of the target imaging device. When the display requirement is color display, the image signal of the imaging device corresponding to the single reflection spectroscopy is mirrored, and the image signals of all three imaging devices are displayed simultaneously.

[0060] When the display requirement is a separate display, the target imaging device is determined according to the band to be displayed in the user's requirement. For example, the user's requirement may be to display only the image formed by the second sub-photon band light wave of the 1.5 micron to 2 micron band, and the main controller uses the second imaging device 500 corresponding to the 1.5 micron to 2 micron band as the target imaging device. Determining whether the target imaging device is an imaging device corresponding to a single reflection spectral means: determining whether the spectral received by the target imaging device is only reflected once.

[0061] As in Figure 1-2In the illustrated embodiment, the first sub-band light wave is a single reflection light wave 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 end of the color display for display; the second sub-band light wave is a single reflection light wave 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 end of the color display for display; and the third sub-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 end 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 end of the color display for display in different colors, so that a color image can be displayed on the display, thereby realizing color imaging of the scene target in the short-wave infrared multi-band common optical path.

[0063] or in Figure 3-4 In the illustrated embodiment, the first sub-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 end of the color display for display. The second sub-band light wave is a double-side reflection split light 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 end of the color display for display. The third sub-band light wave is a single reflection split light 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 end 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 and the image signals of the first imaging device 400 and the second imaging device 500 are simultaneously transmitted to the RGB input end of the color display for display in different colors, so that a color image can be displayed on the display, thereby realizing color imaging of the scene target in the short-wave infrared multi-band common optical path.

[0065] The above is only a specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the technical field, within the technical scope disclosed by the present invention, such as scaling the system or other simple and easy changes or replacements, should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A short-wave infrared color imaging optical system, characterized in that: include: Common optical path objective lens, beam splitting assembly and three imaging devices; The common optical path objective lens is used to receive and converge the incident light wave, and emit the converged light wave to the light splitting component, and the light splitting component is used to perform dichroic light splitting on the converged light wave into three sub-band light waves, which are imaged on the three imaging devices respectively; The wavelength ranges of the three sub-band light waves are different.

2. The short-wave infrared color imaging optical system according to claim 1, characterized in that: The light splitting component includes a first light splitting component and a second light splitting component; The three imaging devices include a first imaging device, a second imaging device and a third imaging device; The first spectroscopic component is used to perform dichroic spectroscopic separation on the incident light wave into a first spectroscopic sub-band light wave and an intermediate spectroscopic sub-band light wave, the first spectroscopic sub-band light wave is imaged on a first imaging device, the intermediate spectroscopic sub-band light wave is transmitted to the second spectroscopic component, the second spectroscopic component is used to split the intermediate spectroscopic sub-band light wave into a second spectroscopic sub-band light wave and a third spectroscopic sub-band light wave, the second spectroscopic sub-band light wave is imaged on the second imaging device, and the third spectroscopic sub-band light wave is imaged on the third imaging device.

3. The short-wave infrared color imaging optical system according to claim 2, characterized in that: The first light splitting component includes a first prism and a second prism, the first prism is located between the second prism and the common light path objective lens, and the surface of the first prism relative to the second prism forms an angle of 45 degrees with the optical axis of the common light path objective lens; The second light splitting component includes a third prism and a fourth prism, the third prism is located between the fourth prism and the first light splitting component, and the surface of the third prism relative to the fourth prism forms an angle of 45 degrees with the optical axis of the common light path objective lens; A first dichroic film is disposed on the surface of the first prism opposite to the second prism, and the first dichroic film is used to perform a first splitting of the incident light wave: reflecting to form the first sub-band light wave, and transmitting to form the intermediate sub-band light wave; a second dichroic film is disposed on the surface of the third prism opposite to the fourth prism, and the second dichroic film is used to perform a second splitting of the incident light wave: reflecting to form the second sub-band light wave, and transmitting to form the third sub-band light wave; Alternatively, a first dichroic film is arranged on the surface of the first prism opposite to the second prism, and the first dichroic film is used to perform a first dichroic separation on the incident light wave: reflecting to form the intermediate sub-band light wave, and transmitting to form the first sub-band light wave; and a second dichroic film is arranged on the surface of the third prism opposite to the fourth prism, and the second dichroic film is used to perform a second dichroic separation on the incident light wave: reflecting to form the second sub-band light wave, and transmitting to form the third sub-band light wave.

4. The short-wave infrared color imaging optical system according to claim 3, characterized in that: 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 is preset between the first prism and the second prism, and an air gap is preset between the third prism and the fourth prism.

5. The short-wave infrared color imaging optical system according to claim 2, characterized in that: The wavelength range of the first sub-photon band light wave, the wavelength range of the second sub-photon band light wave, and the wavelength range of the third sub-photon band light wave are within the short-wave infrared band, and the wavelength range of the first sub-photon band light wave, the wavelength range of the second sub-photon band light wave, and the wavelength range of the third sub-photon band light wave do not overlap with each other.

6. The short-wave infrared color imaging optical system according to claim 2, characterized in that: 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 micron to 2.5 microns, and are located in the focal plane of the common optical path objective mirror.

7. The short-wave infrared color imaging optical system according to claim 2, characterized in that: The optical system further comprises: A compensation mirror is located between the first light splitting component and the first imaging device.

8. The short-wave infrared color imaging optical system according to claim 1, characterized in that: The common light path objective lens is a coaxial optical system in the form of four groups of six lenses, including: a first lens, a second lens, a third lens and a fourth lens coaxially arranged in sequence in a direction close to the light splitting component; The first lens is at least used for transmitting and focusing the incident light wave, the second lens and the third lens are at least used for correcting the chromatic aberration of the light wave transmitted by the first lens, and the fourth lens is at least used 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 is an aspherical lens.

9. The short-wave infrared color imaging optical system according to claim 8, characterized in that: The common light path objective lens further includes an aperture, and the aperture is arranged between the second lens and the third lens.

10. A short-wave infrared color imaging method, based on the short-wave infrared color imaging optical system according to any one of claims 1 to 9, characterized in that: The method comprises: The incident light wave in the short-wave band is split into two dichroic beams to form light waves in three sub-bands, which are imaged on three colloidal quantum dot short-wave infrared imaging devices respectively; Obtain display requirements and determine the type of display requirements; When the display requirement is a separate display of a certain sub-band, a target imaging device is obtained to determine whether the target imaging device is an imaging device corresponding to single reflection spectroscopy; 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 directly displayed; When the display requirement is color display, the image signal of the imaging device corresponding to the single reflection splitting is mirrored, and then the image signals of all three imaging devices are displayed simultaneously.

Images