Optical instrument, optical imaging system and imaging method

Abstract

The application provides an optical instrument, an optical imaging system and an imaging method, and relates to the field of optical endoscopic imaging. The optical instrument has an excitation light path, and the optical instrument comprises: a light path folding assembly, wherein the light path folding assembly comprises at least two mirrors, the at least two mirrors are arranged in a non-coaxial manner in the excitation light path, and are used for folding the incident first light beam at least twice in different directions to compress the light path space. The application can reduce the overall volume of the optical instrument and shorten the rigidity length of the miniaturized multi-photon endoscope probe.

Description

Technical Field

[0001] This application relates to the field of optical endoscopic imaging technology, specifically to an optical instrument, an optical imaging system, and an imaging method. Background Technology

[0002] Miniaturized multiphoton endoscopy is a high-resolution optical biopsy imaging instrument based on the principle of multiphoton excitation. It can achieve high spatiotemporal resolution tomographic imaging of biological tissues and provide functional imaging of cell metabolism information. It has important application prospects in the fields of tumor invasion depth diagnosis and detection of residual cancer at surgical margins.

[0003] The instrument can be divided into two schemes based on the position of the scanning device: proximal scanning and distal scanning. Among them, the distal scanning scheme has become the mainstream configuration due to its superior imaging performance. However, the endoscope probe in the distal scanning scheme has a longer rigid length, which limits its application in clinical practice. Summary of the Invention

[0004] In view of the above, embodiments of this application provide an optical instrument, an optical imaging system, and an imaging method.

[0005] In a first aspect, one embodiment of this application provides an optical instrument having an excitation optical path. The optical instrument includes an optical path deflection assembly, wherein the optical path deflection assembly includes at least two mirrors arranged in a non-coaxial manner in the excitation optical path for deflecting the incident first beam at least twice in different directions to compress the optical path space.

[0006] In conjunction with the first aspect, in some implementations of the first aspect, the optical instrument further includes a light collection path, and the optical instrument further includes a dichroic mirror for separating the excitation light path and the light collection path; preferably, in the excitation light path, the dichroic mirror is used to reflect excitation light in a first wavelength range in the first light beam; in the light collection path, the dichroic mirror is used to transmit fluorescence signals in a second wavelength range.

[0007] In conjunction with the first aspect, in some implementations of the first aspect, the dichroic mirror is located between the first and second reflecting mirrors, wherein the first and second reflecting mirrors are two of at least two reflecting mirrors.

[0008] In conjunction with the first aspect, in some implementations of the first aspect, the optical instrument further includes a galvanometer located downstream of the optical path deflection assembly in the excitation optical path. The galvanometer is used to receive the first beam after being deflected in at least two different directions and to perform a two-dimensional scan on the first beam after being deflected in at least two different directions to generate the beam scanning path required for imaging.

[0009] In conjunction with the first aspect, in some implementations of the first aspect, the galvanometer includes a microelectromechanical system (MEMS) scanning galvanometer, wherein the chip size of the MEMS scanning galvanometer is smaller than a first preset size, and the mirror size of the MEMS scanning galvanometer is smaller than a second preset size, wherein the first preset size and the second preset size are set based on the working channel of the digestive tract examination endoscope.

[0010] In conjunction with the first aspect, some implementations of the first aspect further include a collimating lens located in the excitation optical path for collimating the laser beam into the first beam; preferably, the first beam is transmitted in the optical path deflection assembly as parallel light.

[0011] In conjunction with the first aspect, in some implementations of the first aspect, the laser beam includes a femtosecond pulsed laser beam, and the optical instrument further includes an excitation fiber located in the excitation optical path, the excitation fiber being used to transmit the femtosecond pulsed laser beam; preferably, the excitation fiber includes a photonic crystal fiber.

[0012] In conjunction with the first aspect, in some implementations of the first aspect, the optical instrument further includes a collecting lens and a collecting fiber located in the collecting optical path; wherein the collecting lens is used to focus the fluorescence signal in the second wavelength range transmitted by the dichroic mirror onto the collecting fiber; and the collecting fiber is used to collect and transmit the fluorescence signal in the second wavelength range.

[0013] Secondly, one embodiment of this application provides an optical imaging system, comprising: the optical instrument described in the first aspect, used to acquire fluorescence signals of a target sample; and a host computer, used to reconstruct an image based on the fluorescence signals acquired by the optical instrument.

[0014] Thirdly, one embodiment of this application provides an imaging method, comprising: determining a detection region of a target sample; and using the optical instrument described in the first aspect to acquire fluorescence signals of the detection region, so as to generate an image corresponding to the detection region based on the fluorescence signals.

[0015] In the design of optical instruments for biomedical imaging, optical paths are typically laid out along a straight line or around a central axis. This layout results in a relatively large size for the optical instruments, making it difficult to meet the miniaturization and high-performance requirements of applications such as miniaturized multiphoton endoscopes. To address this issue, this application introduces an optical path folding assembly, which includes at least two mirrors arranged in a non-coaxial manner, capable of folding the incident first beam multiple times in different directions. This design allows the optical path to be folded multiple times within a limited space, thereby achieving the same optical function in a more compact space. Simultaneously, it reduces the overall size of the optical instrument, shortens the rigid length of the miniaturized multiphoton endoscope probe, improves its applicability within limited spaces, and also provides possibilities for the clinical application and translation of advanced imaging technologies such as miniaturized multiphoton endoscopes. Attached Figure Description

[0016] The above and other objects, features, and advantages of this application will become more apparent from the more detailed description of the embodiments of this application in conjunction with the accompanying drawings. The drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the embodiments of this application to explain this application and do not constitute a limitation thereof. In the drawings, the same reference numerals generally represent the same components or steps.

[0017] Figure 1 The diagram shown is a structural schematic of an optical instrument provided in an embodiment of this application.

[0018] Figure 2 The diagram shown is a schematic diagram of the excitation optical path provided in an embodiment of this application.

[0019] Figure 3 The diagram shown is a schematic diagram of the optical collection path provided in an embodiment of this application.

[0020] Figure 4 The diagram shown is a schematic diagram of the scanning characteristic test results of a thermoelectric MEMS scanning mirror provided in an embodiment of this application.

[0021] Figure 5 The diagram shown is a schematic diagram of the test results of the imaging resolution provided in an embodiment of this application.

[0022] Figure 6 The diagram shown is a schematic diagram of the test results of the imaging field of view provided in an embodiment of this application.

[0023] Figure 7 The image shown is a schematic diagram of the imaging results of a colon slice sample under different fields of view provided in an embodiment of this application using two-photon endoscopy.

[0024] Figure 8 The diagram shown is a schematic diagram of the structure of an optical imaging system provided in an exemplary embodiment of this application.

[0025] Figure 9 The diagram shown is a flowchart illustrating an imaging method provided in an exemplary embodiment of this application. Detailed Implementation

[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] Figure 1The diagram shown is a structural schematic of an optical instrument provided in an embodiment of this application. Exemplarily, this optical instrument is applied to a miniaturized multiphoton endoscope. Figure 2 The diagram shown is a schematic diagram of the excitation optical path provided in an embodiment of this application. Figure 3 The diagram shown is a schematic diagram of the optical collection path provided in an embodiment of this application.

[0028] First, the optical instrument has the following characteristics: Figure 2 The excitation optical path is shown. Specifically, the excitation optical path is the path used to transmit excitation light in an optical instrument. In the application scenario of miniaturized multiphoton endoscopes, the excitation light is usually light of a specific wavelength, and its function is to excite the target sample to generate multiphoton (such as two-photon) fluorescence signals.

[0029] Continue to refer to Figure 1 The optical instrument of this application includes an optical path deflection assembly 110, which is a key component in the optical instrument used to change the direction of the optical path. Further, the optical path deflection assembly 110 includes at least two mirrors arranged non-coaxially in the excitation optical path to deflect the incident first beam at least twice in different directions, thereby compressing the optical path space.

[0030] In detail, a reflector is an optical element with a highly reflective surface, capable of efficiently reflecting an incident first beam of light in a specific direction. In this embodiment, the reflectors are arranged non-coaxially in the excitation optical path, meaning their optical axes are not on the same straight line, but rather intersect each other at different angles and positions. This non-coaxial arrangement allows the incident first beam of light to be deflected in different directions after multiple reflections, thereby achieving complex optical path steering and optimized spatial layout. For example, the reflector has dimensions of 1.2mm × 1mm and a thickness of 0.2mm, and its average reflectivity is >95% for beams with wavelengths of 350nm-850nm.

[0031] In one example, the optical path deflection assembly 110 consists of three mirrors, labeled M1, M2, and M3. The incident first beam of light first reaches mirror M1, whose optical axis is at an angle (e.g., 45°) to the direction of the incident first beam. Therefore, mirror M1 reflects the first beam in a new direction. Subsequently, the first beam reflected by mirror M1 reaches mirror M2. The optical axis of mirror M2 is different from that of the first mirror and also at an angle (e.g., deflected again by 30°) to the reflection direction of mirror M1, further changing the direction of the first beam reflected by mirror M1. Finally, it reaches mirror M3. The optical axis of mirror M3 is also different from that of the first two mirrors, and it reflects the received beam again to the final target direction.

[0032] In the design of optical instruments for biomedical imaging, optical paths are typically laid out along a straight line or around a central axis. This layout results in a relatively large size for the optical instruments, making it difficult to meet the miniaturization and high-performance requirements of applications such as miniaturized multiphoton endoscopes. To address this issue, this application introduces an optical path folding assembly, which includes at least two mirrors arranged in a non-coaxial manner, capable of folding the incident first beam multiple times in different directions. This design allows the optical path to be folded multiple times within a limited space, thereby achieving the same optical function in a more compact space. Simultaneously, it reduces the overall size of the optical instrument, shortens the rigid length of the miniaturized multiphoton endoscope probe, improves its applicability within limited spaces, and also provides possibilities for the clinical application and translation of advanced imaging technologies such as miniaturized multiphoton endoscopes.

[0033] In some embodiments, the optical instrument also has, for example, Figure 3 The light path shown is the optical path used in optical instruments to capture and transmit the fluorescence signal emitted by the target sample for subsequent imaging or analysis. This design allows the optical instrument to simultaneously excite the target sample and collect the fluorescence signal, thereby improving imaging efficiency and image quality.

[0034] Furthermore, to achieve effective separation of the excitation and collection light paths, a dichroic mirror 120 is introduced into the optical instrument. Specifically, the dichroic mirror 120 is a mirror capable of selectively reflecting or transmitting light according to its wavelength. In this application, the dichroic mirror 120 is applied between the excitation and collection light paths to achieve their separation.

[0035] In detail, in the excitation optical path, the dichroic mirror 120 reflects the excitation light within a first wavelength range of the first beam. After reflection, this excitation light can accurately illuminate the target sample, exciting it to emit a fluorescence signal. In the collection optical path, the dichroic mirror 120 transmits the fluorescence signal within a second wavelength range. That is, because the wavelength of the fluorescence signal is different from the wavelength of the excitation light, the dichroic mirror 120 can effectively separate these fluorescence signals from the excitation light, ensuring that the main fluorescence signal transmitted in the collection optical path is emitted by the target sample, rather than scattered light or other interfering light from the excitation light. For example, the dichroic mirror 120 has dimensions of 1.2 mm × 1 mm and a thickness of 0.2 mm, with an average reflectivity >90% in the 670 nm–850 nm wavelength range.

[0036] In this embodiment, the excitation and collection optical paths are separated by introducing a dichroic mirror. This not only ensures that the excitation light can act efficiently on the target sample, but also guarantees that the collection optical path can accurately capture the fluorescence signal emitted by the target sample. This separation mechanism improves the signal-to-noise ratio of the imaging and enhances the clarity and accuracy of the imaging.

[0037] In some embodiments, the dichroic mirror 120 is located between the first and second reflecting mirrors, wherein the first and second reflecting mirrors are two of at least two reflecting mirrors.

[0038] For example, such as Figure 1 As shown, assuming the first reflecting mirror is 111 and the second reflecting mirror is 112, a dichroic mirror 120 is located between the first reflecting mirror 111 and the second reflecting mirror 112. This arrangement allows the dichroic mirror 120 to reflect excitation light within a first wavelength range in the excitation optical path, ensuring that this excitation light can continue to propagate along a predetermined path and act on the target sample. Simultaneously, in the collection optical path, the dichroic mirror 120 can also transmit fluorescence signals within a second wavelength range emitted by the target sample, thereby achieving effective separation of the excitation light and fluorescence signals. This design not only improves the imaging quality of the optical instrument but also enhances its overall performance, enabling the excitation and collection optical paths to operate efficiently within a compact space, further optimizing the structure and function of the optical instrument.

[0039] In some embodiments, the optical instrument further includes a galvanometer 130, which is located downstream of the optical path deflection assembly 110 in the excitation optical path. The galvanometer 130 is used to receive the first beam after being deflected in at least two different directions and to perform a two-dimensional scan on the first beam after being deflected in at least two different directions to generate the beam scanning path required for imaging.

[0040] Specifically, the galvanometer 130 is located downstream of the optical path deflection assembly 110, meaning that in the propagation path of the excitation light, the galvanometer 130 is positioned after the optical path deflection assembly 110. In other words, the optical path deflection assembly 110 first deflects the incident first beam in at least two different directions, completing the direction adjustment and spatial compression of the optical path before the first beam reaches the galvanometer 130. Then, through the rapid oscillation of the galvanometer 130, the first beam can be scanned point by point on a two-dimensional plane to form a complete image. This design not only improves imaging efficiency but also ensures high resolution and high precision in imaging.

[0041] In this embodiment, the optical path deflection assembly folds and spatially compresses the light beam through the non-coaxial arrangement of mirrors, making the entire optical instrument more compact. The direction and position of the first beam after processing by the optical path deflection assembly are more stable, providing a solid foundation for the galvanometer's two-dimensional scanning and ensuring the accuracy and consistency of the scanning process. Finally, this layout allows the various components of the optical instrument to work efficiently and collaboratively, fully utilizing their respective functions, thereby better facilitating the transition from adjusting the direction of the first beam to two-dimensional scanning, providing a foundation for high-resolution imaging.

[0042] In some embodiments, the galvanometer includes a microelectromechanical system (MEMS) scanning galvanometer, wherein the chip size of the MEMS scanning galvanometer is smaller than a first preset size, and the mirror size of the MEMS scanning galvanometer is smaller than a second preset size, wherein the first preset size and the second preset size are based on the working channel setting of the digestive tract examination endoscope.

[0043] The chip size is smaller than the first preset size and the mirror size is smaller than the second preset size, mainly to ensure that the size of the microelectromechanical system (MEMS) scanning galvanometer must meet specific application requirements, namely, to be able to fit the working channel of the digestive tract examination endoscope.

[0044] Specifically, the working channel of a gastrointestinal endoscope is a passage used to accommodate various examination and treatment instruments, and its diameter and space are limited. Therefore, in order to ensure that the MEMS scanning galvanometer can be smoothly integrated into the probe of the gastrointestinal endoscope and pass smoothly through the working channel during actual examinations, its chip size and mirror size must be controlled within a certain range, that is, smaller than the preset maximum allowable size (first preset size and second preset size).

[0045] For example, assuming the diameter of the working channel of a gastrointestinal endoscope is 2.8 mm, the first preset size (the maximum allowable size of the chip) is set to be less than 2.8 mm to ensure that the chip can pass smoothly through the working channel. Similarly, the second preset size of the mirror surface is also set according to the actual space of the working channel to ensure that the mirror surface is not too large to fit. For example, the chip size of a MEMS scanning galvanometer is approximately 1.5 mm, which is significantly smaller than the limitation of the working channel (2.8 mm) of the gastrointestinal endoscope, thus ensuring that it can be successfully integrated into the probe of the gastrointestinal endoscope and work normally during actual examinations.

[0046] Optionally, the MEMS scanning mirror has two modes: resonant scanning and quasi-static deflection. Therefore, after applying a sinusoidal signal to its fast axis (such as the X-axis) and a ramp signal to its slow axis (such as the Y-axis), the MEMS scanning mirror can achieve two-dimensional grid scanning imaging of the beam.

[0047] Furthermore, a driving signal is applied to the dual axes (X-axis and Y-axis) of the MEMS scanning mirror through a signal generator to test its scanning characteristics along the X-axis and Y-axis. Optionally, the MEMS scanning mirror includes thermoelectric scanning mirrors, electrostatic scanning mirrors, etc. Figure 4 The diagram shows the results of scanning characteristic testing of a thermoelectric MEMS scanning mirror according to an embodiment of this application. For example, with a driving voltage of 1.6V and a polarization voltage of 0.8V, the test results of the mechanical scanning angles of the thermoelectric MEMS mirror along the X and Y axes in the 0-15Hz frequency range are as follows. Figure 4 As shown in (a). The test results show that the thermoelectric MEMS scanning mirror exhibits quasi-static characteristics in the frequency range of 0-15Hz. The mechanical scanning half-angle of the X-axis is 0.84°±0.008° and the mechanical scanning half-angle of the Y-axis is 0.68°±0.009° in this frequency range.

[0048] In addition, the test results of the mechanical scanning angle of the thermoelectric MEMS scanning mirror as a function of frequency in the X-axis and Y-axis range of 2720-2820Hz are as follows: Figure 4 As shown in (b), the test results show that the resonant frequencies of the X-axis and Y-axis are 2780Hz and 2765Hz, respectively. Furthermore, at an operating frequency of 2750Hz, the mechanical scan half-angles of the X-axis and Y-axis are approximately 1.31° and 1.30°, respectively. At 2775Hz, the mechanical scan half-angles of the X-axis and Y-axis are approximately 3.24° and 2.06°, respectively.

[0049] In summary, although MEMS scanning mirrors are symmetrical devices, their X-axis and Y-axis driving frequency responses are not entirely identical, but exhibit certain differences. In actual multiphoton imaging, the fast axis (X-axis) operating frequency is selected as 2750 Hz, and the slow axis (Y-axis) operating frequency is approximately 5.4 Hz. That is, the fast axis operates in a near-resonant state, while the slow axis operates in a quasi-static state, thus achieving two-dimensional grid scanning.

[0050] This solution ensures that the MEMS scanning galvanometer can move freely within the working channel of the gastrointestinal endoscope by controlling the chip size and mirror size within a preset range, without affecting other functions of the endoscope, such as image acquisition and transmission. This design not only considers technical feasibility but also takes into account space constraints in practical applications, thus expanding the practicality of optical instruments.

[0051] In some embodiments, the optical instrument further includes a collimating lens 140 located in the excitation optical path for collimating the laser beam into the first beam. Optionally, the first beam is transmitted as parallel light in the optical path deflection assembly 110.

[0052] The core function of the collimating lens 140 is to collimate the laser beam to form a first beam, which can then be transmitted in the subsequent optical path as parallel light. Exemplarily, the collimating lens 140 is a GRIN lens (Gradient Index Lens), whose refractive index gradually changes radially or axially, enabling smooth light convergence and imaging. Alternatively, the collimating lens 140 can also be an aspherical lens, which will not be elaborated further in this embodiment. Optionally, the dimensions (outer diameter × length) of the collimating lens 140 are 1mm × 2.06mm, with an effective focal length of approximately 0.94mm, a working distance of approximately 0.12mm, and collimated spot sizes of approximately 359.3μm and 356.9μm in the X and Y directions, respectively.

[0053] Understandably, laser beams typically have a certain divergence angle, and direct use may lead to rapid attenuation of light energy during transmission, or prevent the formation of an ideal focusing effect on subsequent optical components. The collimating lens 140 effectively adjusts the diverging laser beam into a parallel beam (i.e., the first beam), ensuring a relatively stable energy distribution and directionality of light energy over a longer transmission distance. Furthermore, the collimated first beam, upon entering the optical path deflection assembly 110, can be transmitted as parallel light, thereby ensuring that the first beam does not experience unnecessary aberrations or energy loss due to divergence or convergence during deflection.

[0054] This design not only improves the overall efficiency of the optical instrument but also ensures that the first beam maintains good optical characteristics during subsequent optical processing, such as achieving the desired effect when focusing, imaging, or exciting the target sample to emit fluorescence signals. Furthermore, through the synergistic effect of the collimating lens and the optical path deflection assembly, the optical instrument can achieve complex optical functions within a limited space while ensuring the quality and transmission efficiency of the first beam.

[0055] In some embodiments, the laser beam includes a femtosecond pulsed laser beam, and the optical instrument further includes an excitation fiber 150 located in the excitation optical path, the excitation fiber 150 being used to transmit the femtosecond pulsed laser beam. Optionally, the excitation fiber 150 includes a photonic crystal fiber.

[0056] Multiphoton imaging technology primarily relies on the high energy density of femtosecond pulsed lasers, which cause fluorescent molecules to emit fluorescence after absorbing multiple low-energy photons, thus achieving high-resolution imaging. However, to effectively realize the multiphoton effect, the transmission process of the laser beam must maintain high fidelity, especially avoiding the influence of dispersion on the pulse width and energy distribution. Therefore, an excitation fiber 150 located in the excitation optical path is introduced into the optical instrument to transmit the femtosecond pulsed laser beam. For example, the center wavelength of the femtosecond pulsed laser beam is 780 nm, and the output repetition frequency is 80 MHz.

[0057] Furthermore, traditional optical fibers may introduce dispersion, causing pulse broadening of the femtosecond laser beam during transmission, thereby reducing the peak power of the femtosecond laser beam and affecting the excitation efficiency of the multiphoton effect. To avoid this, the excitation fiber 150 uses photonic crystal fiber. Specifically, the air-hole arrangement microstructure inside the photonic crystal fiber can effectively confine the propagation direction of the femtosecond laser beam while significantly reducing its dispersion, thus ensuring the time-domain characteristics of the femtosecond laser beam on the order of hundreds of femtoseconds during transmission. For example, the core diameter of the photonic crystal fiber is 7.5±1μm, the cladding diameter is 130±5μm, the coating diameter is 220±50μm, and the coating material is acrylate.

[0058] Optionally, in some embodiments, a femtosecond pulsed laser is used to emit a femtosecond pulsed laser beam, which enters the excitation fiber 150 after passing through a coupling lens (not shown).

[0059] This scheme employs a femtosecond pulsed laser as the excitation source and transmits the laser beam via a photonic crystal fiber. This design not only enables highly efficient multiphoton imaging but also maintains stability and reliability in complex imaging environments. Furthermore, the low-dispersion photonic crystal fiber provides an ideal transmission medium for femtosecond pulsed lasers, enabling the optical instrument provided in this application to play a crucial role in biomedical imaging, especially in scenarios requiring high resolution and high sensitivity.

[0060] In some embodiments, the optical instrument further includes a collecting lens 160 and a collecting fiber 170 located in the collecting optical path; wherein the collecting lens 160 is used to focus the fluorescence signal in the second wavelength range transmitted by the dichroic mirror 120 onto the collecting fiber 170; and the collecting fiber 170 is used to collect and transmit the fluorescence signal in the second wavelength range.

[0061] Optical instruments typically involve the interaction of excitation light with a target sample to generate fluorescence signals. These fluorescence signals contain information about the structure and composition of the target sample, serving as crucial evidence for imaging or detection. However, fluorescence signals are often weak and dispersed, leading to inefficiency and signal loss when directly collecting and transmitting them. To address this, a collecting lens 160 is incorporated into the collecting optical path to focus the fluorescence signals transmitted by the dichroic mirror 120 within a specific wavelength range (i.e., the second wavelength range), converging them into a smaller area and thus improving the intensity and concentration of the fluorescence signal. Subsequently, the focused fluorescence signal is guided to a collecting optical fiber 170. The collecting optical fiber 170 efficiently collects these focused fluorescence signals and transmits them to subsequent detection or imaging systems.

[0062] For example, the collecting fiber 170 is a quartz fiber with a core diameter of 400 μm, a cladding diameter of 428 μm, a coating diameter of 730 μm, a numerical aperture of 0.37, and a transmission length of approximately 1 m.

[0063] In some embodiments, the transmission efficiency of 1m silica optical fiber is approximately 81% at a wavelength of 520nm and approximately 76% at a wavelength of 488nm.

[0064] In some embodiments, the other end of the collecting fiber 170 is connected to the collecting module of a miniaturized multiphoton endoscope via an interface. For example, the collecting module uses a 420nm-580nm filter to collect the multiphoton excitation fluorescence signal of the target sample, and then transmits it to a host computer for image reconstruction and display.

[0065] In this embodiment, the fluorescence emitted by the target sample is typically divergent and weak. The collecting lens can focus these dispersed fluorescence signals into a smaller area, thereby significantly improving the intensity and concentration of the fluorescence signal. Furthermore, the collecting optical fiber features low loss and high transmission efficiency, which not only improves the collection efficiency of the fluorescence signal but also reduces the attenuation of the fluorescence signal during transmission, enabling optical instruments to effectively transmit and process fluorescence signals over long distances or through complex optical paths.

[0066] In one example, fluorescent microbeads with a diameter of 380 nm were selected as the resolution test sample for the optical instrument provided in this application. The 380 nm diameter fluorescent microbeads satisfy the optical Nyquist sampling theorem, thus allowing the acquisition of the imaging resolution index of the actual system.

[0067] Figure 5 The diagram shown is a schematic diagram of the test results of the imaging resolution provided in an embodiment of this application. Figure 5 (a) shows the lateral resolution test results of fluorescent microbeads 1; Figure 5 (b) shows the lateral resolution test results of fluorescent microbeads 2; Figure 5 (a) The inset in the upper left corner shows the two-photon imaging results of fluorescent microbeads 1 and 2. After Gaussian fitting calculation, the full width at half maximum (FWHM) of fluorescent microbeads 1 and 2 are 2.04 μm and 2.07 μm, respectively, and the final imaging resolution test result is 2.055 μm ± 0.021 μm.

[0068] In one example, the optical instrument provided in this application is subjected to an imaging field of view test. For example, a field of view target mask is selected as the imaging field of view calibration sample, which includes square grid array units, each small square having a side length of 25 μm.

[0069] Figure 6The diagram shown is a schematic representation of the test results for the imaging field of view provided in an embodiment of this application. Wherein, Figure 6 (a) shows the test results of the imaging field of view before affine transformation; Figure 6 (b) shows the test results of the imaging field of view after affine transformation. For example... Figure 6 As shown, due to the assembly and adjustment of the MEMS scanning galvanometer, the actual imaging field of view exhibits a rhomboid distortion. To correct this distortion, the data is transformed using an affine transformation matrix. For example, selecting... Figure 6 (a) Points 1, 2, and 3 are transformed, and the transformed field of view test results are as follows: Figure 6 As shown in (b). Wherein, Figure 6 (a) The transformations at points 1, 2, and 3 correspond to Figure 6 (b) Points 1', 2', and 3'. Finally, through calibration, Figure 6 (b) has an imaging field of view of 65μm×100μm.

[0070] In one example, an imaging verification of a colon slice sample was performed. Figure 7 The image shown is a schematic diagram of the imaging results of a colon slice sample under different fields of view provided in an embodiment of this application using two-photon endoscopy. Figure 7 As shown, experimental results demonstrate that multiphoton endoscopes based on small thermoelectric MEMS scanning galvanometers possess the capability for rapid subcellular resolution imaging of biological tissues. The power required for imaging field of view, imaging resolution, and colon slice imaging does not exceed 30mW.

[0071] Furthermore, the mirror size of the ultra-miniature thermoelectric MEMS scanning galvanometer is relatively small (approximately 0.55mm × 0.55mm). This results in a relatively low effective excitation numerical aperture and effective collection numerical aperture (not exceeding 0.21) in this configuration. To further improve imaging resolution, this application can also use a collimating lens with a longer focal length to increase the beam diameter, thereby further improving the imaging resolution of the multiphoton endoscope by increasing the mirror size of the MEMS scanning galvanometer. Taking full account of the probe sealing process, the probe of this miniaturized multiphoton endoscope can be inserted through the instrument channel of a white light endoscope, and can be applied to in vivo imaging of the digestive tract.

[0072] In summary, the optical instrument proposed in this application employs a beam splitting design for the excitation and collection optical paths, and combines an ultra-miniature thermoelectric MEMS scanning mirror to achieve rapid two-dimensional grid scanning. For example, the final miniaturized multiphoton endoscope achieves an imaging resolution of 2.055 μm ± 0.021 μm, an imaging field of view of 65 μm × 100 μm, an imaging frame rate of 5.4 fps, and integrated probe dimensions (width × height × length) of 2.7 mm × 3 mm × 7.3 mm. Imaging colon slices validated its optical biopsy capability for multiphoton endoscopic microscopy imaging at subcellular resolution.

[0073] Figure 8 The diagram shown is a schematic diagram of the structure of an optical imaging system provided in an exemplary embodiment of this application.

[0074] like Figure 8 As shown, the optical imaging system provided in this application embodiment includes:

[0075] Optical instrument 810 is used to collect fluorescence signals of target samples, and the optical instrument is the optical instrument described in any embodiment of this application;

[0076] The host computer 820 is used for image reconstruction based on fluorescence signals acquired by optical instruments.

[0077] Optionally, the host computer 820 includes a fluorescence signal collection module and a data acquisition and image reconstruction module.

[0078] Specifically, the fluorescence signal is collected by a collecting lens and sent to a fluorescence signal collection module, which contains a photomultiplier tube to convert the fluorescence signal into an electrical signal. The data acquisition and image reconstruction module receives the electrical signal and performs image reconstruction.

[0079] Optionally, the host computer 820 also includes a galvanometer drive module for sending drive signals to achieve galvanometer scanning. Furthermore, the fluorescence signal collection module and the galvanometer drive module synchronize data to ensure that the collected fluorescence signal can be reconstructed according to the trajectory of the drive signal.

[0080] Figure 9 The diagram shown is a schematic flowchart of an imaging method provided in an exemplary embodiment of this application. Figure 9 As shown, the imaging method includes the following steps.

[0081] Step S910: Determine the detection area of ​​the target sample;

[0082] Step S920: Based on the optical instrument described in any embodiment of this application, the fluorescence signal of the detection area is collected so as to generate an image corresponding to the detection area based on the fluorescence signal.

[0083] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0084] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0085] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of this application.

[0086] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0087] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. An optical instrument, characterized in that, An optical instrument for use in miniaturized multiphoton endoscopes, the optical instrument having an excitation optical path, the optical instrument comprising: An optical path deflection assembly, wherein the optical path deflection assembly includes at least two mirrors arranged in a non-coaxial manner in the excitation optical path for deflecting the incident first beam in at least two different directions to compress the optical path space.

2. The optical instrument according to claim 1, characterized in that, The optical instrument also has a light collection path, and the optical instrument further includes a dichroic mirror for separating the excitation light path and the light collection path; Preferably, in the excitation optical path, the dichroic mirror is used to reflect the excitation light in the first wavelength range of the first beam; in the collection optical path, the dichroic mirror is used to transmit the fluorescence signal in the second wavelength range.

3. The optical instrument according to claim 2, characterized in that, The dichroic mirror is located between the first and second reflecting mirrors, wherein the first and second reflecting mirrors are two of the at least two reflecting mirrors.

4. The optical instrument according to any one of claims 1 to 3, characterized in that, It also includes a galvanometer, which is located downstream of the optical path deflection assembly in the excitation optical path. The galvanometer is used to receive the first beam after it has been deflected in at least two different directions, and to perform a two-dimensional scan on the first beam after it has been deflected in at least two different directions to generate the beam scanning path required for imaging.

5. The optical instrument according to claim 4, characterized in that, The galvanometer includes a microelectromechanical system (MEMS) scanning galvanometer. The chip size of the MEMS scanning galvanometer is smaller than a first preset size, and the mirror size of the MEMS scanning galvanometer is smaller than a second preset size. The first preset size and the second preset size are set based on the working channel of the digestive tract examination endoscope.

6. The optical instrument according to any one of claims 1 to 3, characterized in that, It also includes a collimating lens located in the excitation optical path for collimating the laser beam into the first beam; Preferably, the first light beam is transmitted in the optical path deflection assembly in the form of parallel light.

7. The optical instrument according to claim 6, characterized in that, The laser beam includes a femtosecond pulsed laser beam, and the optical instrument further includes an excitation fiber located in the excitation optical path, the excitation fiber being used to transmit the femtosecond pulsed laser beam; Preferably, the excitation fiber comprises a photonic crystal fiber.

8. The optical instrument according to claim 2 or 3, characterized in that, It also includes a collecting lens and a collecting optical fiber located in the collecting optical path; The collecting lens is used to focus the fluorescence signal in the second wavelength range transmitted by the dichroic mirror onto the collecting optical fiber; The collecting optical fiber is used to collect and conduct fluorescence signals within the second wavelength range.

9. An optical imaging system, characterized in that, include: The optical instrument according to any one of claims 1 to 8 is used to collect fluorescence signals of a target sample; The host computer is used to reconstruct the image based on the fluorescence signal collected by the optical instrument.

10. An imaging method, characterized in that, include: Determine the detection area of ​​the target sample; Using the optical instrument according to any one of claims 1 to 8, fluorescence signals of the detection area are collected so as to generate an image corresponding to the detection area based on the fluorescence signals.

Images