A line-scan spectral optical coherence tomography system and apparatus

Abstract

The application provides a line scanning spectral optical coherence tomography system and device, wherein the imaging system comprises a light source generating device, a light splitting device, a reference arm, a sample arm, a signal detecting device and a signal generator; the sample arm is provided with a MEMS galvanometer and a one-dimensional scanning galvanometer, and the sample arm light path is turned on or turned off by controlling the angle deflection of the MEMS galvanometer; only in the light path turning-on period during the exposure of the area array camera, the total light energy received by the sample tissue in the area array camera shooting period is equal to the effective light energy, the light utilization rate is significantly improved, the light power time sequence is synchronously controlled, the signal-to-noise ratio is enhanced under the premise of maintaining the safe light dose of the sample tissue, and high-quality imaging is realized.

Description

Technical Field

[0001] This invention belongs to the field of optical imaging technology, and particularly relates to a line-scan spectral optical coherence tomography system. Background Technology

[0002] Line Scanning Spectral Domain Optical Coherence Tomography (LSSDOCT) systems use a line light source to scan sample tissues, combine the backscattered light from the sample tissues with the interference of the reference light, acquire the signal using a two-dimensional area array camera, and finally extract the axial information of the sample tissues using Fourier transform. This is a non-invasive, low-cost, and non-traumatic high-resolution imaging method.

[0003] Compared to traditional point-scan optical coherence tomography (PSOCT) systems, LSSDOCT systems offer faster imaging speeds. However, the light utilization rate of LSSDOCT is far lower than that of PSOCT. PSOCT systems typically utilize a one-dimensional linear array camera for signal acquisition, where the exposure time of the detector accounts for up to 90% of the sampling time, achieving a very high ideal light utilization rate. In contrast, traditional LSSDOCT systems have very low light utilization. For example, for a two-dimensional area array camera with a frame rate of 200fps, its shooting cycle is 5ms, and the exposure time is 500μs, meaning the exposure time accounts for 10% of the shooting cycle. During the time the light beam illuminates the sample tissue surface, only the light during the exposure time is effectively utilized; the light on the sample tissue is ineffective for the remaining time. Therefore, if the light power illuminating the sample tissue surface is 10mW, the total light energy received by the sample tissue during the shooting cycle is 5×10⁻⁶. -5 J, the effective light energy utilized is 5 × 10 -6 J represents the remaining light energy that is not utilized, with a light utilization rate of only 10%, which is nearly 10 times lower than the light utilization rate of PSOCT.

[0004] Therefore, how to improve the utilization rate of ineffective light without damaging the sample tissue due to photothermal effects is an urgent problem to be solved. Summary of the Invention

[0005] This invention provides a line-scan spectral optical coherence tomography system and device to solve the problem of how to improve the utilization rate of ineffective light without causing damage to sample tissue by photothermal effects.

[0006] In a first aspect, the present invention provides a line-scan spectral optical coherence tomography system, comprising:

[0007] A light source generating device used to emit a light beam;

[0008] A beam splitter is located at an extension of the beam emission direction of the light source generator and is used to split the beam emitted by the light source generator into a first beam and a second beam.

[0009] A reference arm, located in the optical path of the first beam, is used to receive the first beam emitted by the beam splitter and reflect the first beam back to the beam splitter.

[0010] The sample arm, located in the optical path of the second beam, is used to receive the second beam emitted by the spectrometer and irradiate the sample tissue with the second beam. The backscattered light carrying sample tissue information returns to the spectrometer along the original path.

[0011] The sample arm includes a MEMS galvanometer and a one-dimensional scanning galvanometer. The MEMS galvanometer is located in the optical path of the second beam. The MEMS galvanometer can be deflected at an angle. When the MEMS galvanometer is not deflected, the second beam is reflected by the MEMS galvanometer and incident on the one-dimensional scanning galvanometer, the optical path is open, and the sample tissue receives illumination. When the MEMS galvanometer is deflected, the second beam is reflected by the MEMS galvanometer and deflected out of the one-dimensional scanning galvanometer, the optical path is cut off, and the sample tissue does not receive illumination.

[0012] The beam splitter is also used to receive the reflected light from the reference arm and the backscattered light from the sample arm carrying sample tissue information. The two beams interfere with each other within the beam splitter to form interference light.

[0013] The signal detection device is set in the opposite direction to the initial emission direction of the first beam. It is used to decompose the interference light into interference spectral signals and convert the interference spectral signals into electrical signals and transmit them to the computer. The computer uses a Fourier transform algorithm to process and reconstruct the sample tissue image.

[0014] The signal detection device includes an area array camera, which is used to convert the interference spectral signal into an electrical signal and transmit it to a computer.

[0015] A signal generator, electrically connected to the MEMS galvanometer, the one-dimensional scanning galvanometer, and the area array camera, is used to generate the deflection timing of the MEMS galvanometer, the scanning voltage stepping timing of the one-dimensional scanning galvanometer, and the shooting timing of the area array camera.

[0016] Optionally, the light source generating device includes:

[0017] A broadband light source is used to generate the first low-coherence light;

[0018] A spectral filter, located in the optical path of the first low-coherence light, is used to filter the first low-coherence light within the target spectral range to obtain the second low-coherence light;

[0019] The beam-expanding lens group is located in the optical path of the second low-coherence light and is used to expand the second low-coherence light to obtain the third low-coherence light;

[0020] A cylindrical mirror, located in the optical path of the third low-coherence light, is used to convert the third low-coherence light into a linear light spot.

[0021] Optionally, the beam-expanding lens group includes a first cemented doublet convex lens and a second cemented doublet convex lens arranged coaxially.

[0022] Optionally, the reference arm includes:

[0023] A neutral density filter is located in the optical path from which the first beam is emitted by the beam splitter, and is used to reduce the optical power of the first beam;

[0024] The first microscope objective is located on the side of the neutral density filter away from the beam splitter, and is used to receive the light emitted by the neutral density filter and illuminate the first plane mirror with the received light.

[0025] The first plane mirror is located in the light-emitting direction of the first microscope objective and is used to reflect the received first light beam to the neutral density filter.

[0026] The neutral density filter is also used to transmit the received reflected light to the beam splitter.

[0027] Optionally, the sample arm further includes:

[0028] The second microscope objective is located in the light-emitting direction of the one-dimensional scanning galvanometer and is used to receive the light emitted by the one-dimensional scanning galvanometer and irradiate the sample tissue with the received light.

[0029] The second microscope objective is also used to receive the backscattered light carrying the sample tissue information;

[0030] The one-dimensional scanning galvanometer is also used to receive backscattered light carrying sample tissue information transmitted through the second microscope objective, and to transmit the backscattered light carrying sample tissue information back to the spectrometer through the MEMS galvanometer.

[0031] Optionally, the signal detection device further includes:

[0032] A beam-constricting lens group is located in the optical path of the interference light emitted from the beam splitter and is used to reduce the interference light beam.

[0033] A grating, located in the optical path of the beam-contracted interference light, is used to split the beam-contracted interference light to obtain interference light of different wavelengths;

[0034] The third doublet convex lens is located in the optical path of interference light of different wavelengths and is used to focus interference light of different wavelengths onto a column of pixels of the area array camera.

[0035] Optionally, the signal detection device further includes a second planar reflector located on the optical path of the interference light emitted by the beam splitter, for changing the optical path of the interference light.

[0036] Optionally, the beam-constricting lens group includes a fourth cemented doublet convex lens and a fifth cemented doublet convex lens arranged coaxially; a slit stop is provided between the fourth cemented doublet convex lens and the fifth cemented doublet convex lens; the focal point of the fourth cemented doublet convex lens is located within the slit of the slit stop.

[0037] Optionally, the broadband light source includes a broadband light-emitting diode light source or a broadband light-emitting diode light source.

[0038] In a second aspect, the present invention provides a line-scan spectral optical coherence tomography device, including the line-scan spectral optical coherence tomography system as described in the first aspect.

[0039] This invention provides a line-scanning spectral optical coherence tomography system and device, in which a MEMS galvanometer is placed in the sample arm, positioned before a one-dimensional scanning galvanometer. To improve the light utilization rate of the imaging system, the MEMS galvanometer is used to deflect the light beam to control the conduction or cutoff of the reference arm optical path, ensuring that the total light energy received by the sample tissue during the imaging cycle of the area array camera equals the effectively utilized light energy. This not only significantly improves the light utilization rate of the imaging system but also maintains the original imaging quality.

[0040] After improving the light utilization rate, the illumination power on the sample tissue surface is further increased. With the light utilization rate of the imaging system adjusted to a high efficiency by the MEMS galvanometer, the illumination power can be further enhanced. Within one frame cycle captured by the area array camera, the light power is significantly increased during the exposure time by temporal control, while there is no light power outside the exposure time. This maintains the light power received by the sample tissue at a level consistent with that of a traditional LSSDOCT system. Therefore, without causing phototoxicity, the signal-to-noise ratio of the entire imaging system can be improved, thus enhancing the imaging quality of the sample tissue. Attached Figure Description

[0041] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 A schematic diagram of a line-scan spectral optical coherence tomography system provided in an embodiment of the present invention;

[0043] Figure 2 This is another schematic diagram of a line-scan spectral optical coherence tomography system provided in an embodiment of the present invention;

[0044] Figure 3 This is a schematic diagram of the sample arm optical path being cut off when the MEMS galvanometer is deflected, provided in an embodiment of the present invention.

[0045] Figure 4 A schematic optical path diagram for imaging sample tissue in the yz plane and xz plane, respectively, as provided in the embodiments of the present invention;

[0046] Figure 5 Timing diagrams of the one-dimensional scanning galvanometer drive signal, MEMS galvanometer drive signal, and area array camera exposure signal provided for embodiments of the present invention.

[0047] The components include: 1. Light source generating device; 11. Broadband light source; 12. Spectral filter; 13. Beam expander lens group; 131. First cemented doublet convex lens; 132. Second cemented doublet convex lens; 14. Cylindrical mirror; 2. Beam splitter; 3. Reference arm; 31. Neutral density filter; 32. First microscope objective; 33. First plane mirror; 4. Sample arm; 41. MEMS galvanometer; 42. One-dimensional scanning galvanometer; 43. Second microscope objective; 5. Signal detection device; 51. Area array camera; 52. Beam reducer lens group; 521. Fourth cemented doublet convex lens; 522. Fifth cemented doublet convex lens; 523. Slit aperture; 53. Grating; 54. Third cemented doublet convex lens; 55. Second plane mirror; 6. Signal generator. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] Example 1

[0050] This invention provides a line-scan spectral optical coherence tomography system, which has higher light utilization than the traditional LSSDOCT system and can achieve high-resolution imaging of low-scattering or high-absorption sample tissues (such as subcutaneous blood vessels, bone tissue, and internal structures of teeth). Figure 1 and Figure 2 As shown, the line-scan spectral optical coherence tomography system includes:

[0051] Light source generating device 1, used to emit a light beam, includes:

[0052] Broadband light source 11, including a broadband light-emitting diode light source or a superluminescent light-emitting diode light source, is used to generate first low-coherence light.

[0053] The spectral filter 12 is located in the optical path of the first low-coherence light and is used to filter out the first low-coherence light within the target spectral range to obtain the second low-coherence light. In this embodiment, the spectral filter 12 is used to extract the spectrum. The spectral range of the broadband light source is 400-1700nm, and the imaging system provided in this embodiment requires a spectral range of 850±50nm.

[0054] The beam expander lens group 13 is located in the optical path of the second low-coherence light and is used to expand the second low-coherence light to obtain the third low-coherence light. The beam expander lens group 13 includes a first cemented doublet convex lens 131 and a second cemented doublet convex lens 132 arranged coaxially; the first cemented doublet convex lens 131 and the second cemented doublet convex lens 132 form a 4F system, which expands the spot diameter of the second low-coherence light and increases the line length and field of view of the imaging illumination.

[0055] Cylindrical mirror 14 is located in the optical path of the third low-coherence light and is used to convert the third low-coherence light into a linear light spot beam to achieve linear illumination.

[0056] The beam splitter 2 is located at an extension of the beam emission direction of the light source generator 1, and is used to split the beam emitted by the light source generator 1 into a first beam and a second beam. In this embodiment, the beam splitter 2 is a beam splitting prism, and the split first beam and second beam enter the reference arm 3 and the sample arm 4, respectively.

[0057] Reference arm 3, located in the optical path of the first beam, is used to receive the first beam emitted by beam splitter 2 and reflect the first beam back to beam splitter 2. Reference arm 3 includes:

[0058] The neutral density filter 31 is located on the optical path from which the first beam is emitted by the beam splitter 2, and is used to reduce the optical power of the first beam.

[0059] The first microscope objective 32 is located on the side of the neutral density filter 31 away from the beam splitter 2. It is used to receive the light emitted by the neutral density filter 31 and to illuminate the first plane mirror 33 with the received light. The light power reflected by the first plane mirror 33 is too high, so the neutral density filter 31 is set to attenuate the light power. The first microscope objective 32 is used for microscopic imaging to achieve micrometer-level resolution.

[0060] The first planar mirror 33 is located in the light-emitting direction of the first microscope objective 32 and is used to reflect the received first light beam to the neutral density filter 31.

[0061] The neutral density filter 31 is also used to transmit the received reflected light to the beam splitter 2.

[0062] Sample arm 4 is located in the optical path of the second beam. It is used to receive the second beam emitted by the spectrometer 2 and irradiate the sample tissue with the second beam. The backscattered light carrying the sample tissue information returns to the spectrometer 2 along the original path.

[0063] Sample arm 4 includes a MEMS galvanometer 41 and a one-dimensional scanning galvanometer 42; the MEMS galvanometer 41 is located in the optical path of the second beam. The MEMS galvanometer 41 can be angled to deflect the direction of the second beam, acting as an optical switch: when the MEMS galvanometer 41 is not angled, the second beam is reflected by the MEMS galvanometer 41 and then incident on the one-dimensional scanning galvanometer 42, the optical path is open, and the sample tissue receives illumination; for example... Figure 3 As shown, when the MEMS galvanometer 41 deflects at an angle, the second beam is reflected by the MEMS galvanometer 41 and deflected out of the one-dimensional scanning galvanometer 42, cutting off the optical path and preventing the sample tissue from receiving light. The one-dimensional scanning galvanometer 42 performs y-axis scanning imaging on the sample tissue to obtain a 3D image of the sample tissue.

[0064] The sample arm 4 also includes a second microscope objective 43, located in the light-emitting direction of the one-dimensional scanning galvanometer 42, for receiving the light emitted by the one-dimensional scanning galvanometer 42 and illuminating the sample tissue with the received light; the second microscope objective 43 is also used to receive backscattered light carrying sample tissue information. The second microscope objective 43 is used for microscopic imaging to achieve micrometer-level resolution.

[0065] The one-dimensional scanning galvanometer 42 is also used to receive backscattered light carrying sample tissue information transmitted through the second microscope objective 43, and transmit the backscattered light carrying sample tissue information back to the spectrometer 2 through the MEMS galvanometer 41.

[0066] The beam splitter 2 is also used to receive the reflected light from the reference arm 3 and the backscattered light from the sample arm 4 carrying sample tissue information. The two beams interfere with each other within the beam splitter 2 to form interference light.

[0067] The signal detection device 5 is positioned in the opposite direction to the initial emission direction of the first beam (i.e., the direction in which the beam splitter 2 emits the first beam). It is used to decompose the interference light into interference spectral signals and convert these signals into electrical signals, which are then transmitted to a computer. The computer uses a Fourier transform algorithm to reconstruct the sample tissue image. The signal detection device 5 includes an area array camera 51, which converts the interference spectral signals into electrical signals for transmission to the computer. The signal detection device 5 also includes:

[0068] The beam-shrinking lens group 52 is located on the optical path of the interference light emitted from the beam splitter 2, and is used to shrink the interference light beam. The beam-shrinking lens group 52 includes a fourth cemented doublet convex lens 521 and a fifth cemented doublet convex lens 522 arranged coaxially, forming a 4F system, which shrinks the beam of the interference light and extends the transmission distance of the interference light. A slit stop 523 is provided between the fourth cemented doublet convex lens 521 and the fifth cemented doublet convex lens 522; the focal point of the fourth cemented doublet convex lens 521 is located within the slit of the slit stop 523.

[0069] The slit stop 523 can effectively filter out some stray light outside the focal plane, further improving the imaging resolution. However, the slit stop 523 will reduce the signal-to-noise ratio of the imaging system. Traditional LSSDOCT systems cannot use the slit stop 523 due to its low signal-to-noise ratio. However, for the line-scan spectral optical coherence tomography system with high signal-to-noise ratio proposed in the embodiment, it balances the contradictory relationship between signal-to-noise ratio and resolution brought about by the slit stop 523. Therefore, a slit stop 523 can be placed in the signal detection optical path of the imaging system to improve the imaging quality of the imaging system.

[0070] Grating 53 is located on the optical path of the interference light after beam contraction. It is used to split the interference light after beam contraction to obtain interference light of different wavelengths.

[0071] The third doublet convex lens 54 is located in the optical path of interference light of different wavelengths and is used to focus interference light of different wavelengths onto a column of pixels of the area array camera.

[0072] The second plane mirror 55 is located on the optical path of the interference light emitted from the beam splitter 2. It is used to change the optical path of the interference light. Compared with the volume of the imaging system without changing the optical path of the interference light, changing the optical path of the interference light can reduce the volume of the imaging system.

[0073] The signal generator 6 is electrically connected to the MEMS galvanometer 41, the one-dimensional scanning galvanometer 42 and the area array camera 51, and is used to generate the deflection timing of the MEMS galvanometer 41, the scanning voltage stepping timing of the one-dimensional scanning galvanometer 42 and the shooting timing of the area array camera 51.

[0074] The light utilization rate of the imaging system is improved by using a MEMS galvanometer 41 to cut off the optical path. After adding the MEMS galvanometer 41 to the sample arm 4, the MEMS galvanometer 41 is rapidly scanned along its axis by a periodic electrical signal. This causes the light within the exposure time of the area array camera 51 to be reflected into the optical path of the sample arm 4, while the light outside the exposure time of the area array camera 51 is reflected out of the optical path of the sample arm 4 by changing the angle of the MEMS galvanometer 41. This ensures that the sample tissue receives light only during the exposure time of the area array camera 51. The rapid scanning axis frequency of the MEMS galvanometer 41 can reach up to about 30kHz, which is on the same order of magnitude as the exposure time of the area array camera 51 (typically ranging from 10 to 600μs). To maximize the light utilization rate, the drive signal of the MEMS galvanometer 41 needs to be highly synchronized with the exposure signal period of the area array camera 51. At this time, the total light energy received by the sample tissue during the imaging cycle is the effectively utilized light energy. This not only significantly improves the light utilization rate of the imaging system, theoretically approaching 100%, but also maintains the original imaging quality of the imaging system. Compared to traditional LSOCT systems, where only about 10% of the energy is actually collected, the light utilization rate of the line-scan spectral optical coherence tomography system proposed in this embodiment is improved by nearly 10 times.

[0075] To achieve high performance, after the illumination utilization rate of the imaging system is adjusted to a high efficiency by the MEMS galvanometer 41, the illumination power can be further enhanced. During one frame period captured by the area array camera 51, the light power is significantly increased during the exposure time by temporal control, while there is no light power outside the exposure time. This maintains the light power received by the sample tissue at the same level as the traditional LSSDOCT system. Therefore, without causing phototoxicity, the signal-to-noise ratio of the entire imaging system can be improved, thus enhancing the imaging quality of the sample tissue. For example, the light power on the sample tissue surface can be increased from 10mW to 100mW. In traditional LSSDOCT, when 100mW of light is used to illuminate the sample tissue surface, the total light energy received by the sample tissue in one frame period is 5 × 10⁻⁶ mW. -4 J; In the LSSDOCT provided in this embodiment, the total light energy received by the sample tissue during one frame of imaging is 5 × 10⁻⁶. -5 J. Although the optical power is amplified 10 times, this energy is the same as the light energy consumed by a traditional LSSDOCT to capture a single frame of a sample at a power of 10mW. Therefore, increasing the illumination power of the sample tissue does not produce phototoxicity, but it can improve the signal-to-noise ratio of the entire imaging system and improve the imaging quality of the sample tissue.

[0076] Signal generator 6 generates three digital electrical signals: the first is the MEMS mirror 41 deflection timing, used to control the deflection time of the MEMS mirror 41; the second is the area scan camera 51 imaging timing (i.e., external trigger acquisition timing), where the exposure time of the area scan camera 51 is adjustable; and the third is the scanning voltage stepping timing of the one-dimensional scanning mirror 42, used to complete the scanning of the sample tissue. Once the exposure time and frame rate of the area scan camera 51 are set, the imaging timing of the area scan camera 51 is roughly determined. The deflection timing of the MEMS mirror 41 and the scanning timing of the one-dimensional scanning mirror 42 are set synchronously based on the imaging timing of the area scan camera 51. During the exposure time of the area scan camera 51, the MEMS mirror 41 timing remains at a low level, without deflection, and the optical path of the sample arm 4 is open, allowing the sample tissue to receive the light signal. After the exposure of the area scan camera 51 is completed, the MEMS mirror 41 timing becomes high, driving the MEMS mirror 41 to deflect at a small angle, reflecting the light out of the sample arm 4, and cutting off the optical path of the sample arm 4. The scanning timing of the one-dimensional scanning galvanometer 42 gradually increases in voltage increments after the start of the imaging sequence. After each frame is captured, the voltage increments by a certain value, and the one-dimensional scanning galvanometer 42 deflects by a unit angle once. This continues until the maximum voltage value is reached after all imaging signals have been captured, at which point the deflection angle of the one-dimensional scanning galvanometer 42 reaches its maximum. After traversing all scanning ranges, the scanning timing of the one-dimensional scanning galvanometer 42 returns to the initial voltage value, and the lens of the one-dimensional scanning galvanometer 42 returns to its initial position.

[0077] like Figure 5 The diagram shows the timing of the driving signals for the one-dimensional scanning galvanometer 42, the MEMS galvanometer 41, and the exposure signal for the area scan camera 51. The timing of the area scan camera 51 is represented by each row of pixels on its sensor. When the sensor is illuminated, the pixels in that row begin to reset before exposure begins. The area scan camera 51 is a global camera, allowing pixels in different rows to be exposed simultaneously. After exposure, data is read from the sensor register. After one frame is read, the sensor performs vertical blanking before the next frame is read, which takes some time. The signal of the one-dimensional scanning galvanometer 42 should also be synchronized with the shooting signal of the area scan camera 51. After each frame is captured, the voltage value is incremented, and the one-dimensional scanning galvanometer 42 deflects by a unit angle until the maximum voltage value is reached after all shooting signals are completed, at which point the deflection angle reaches its maximum. After traversing all scanning ranges, the timing of the one-dimensional scanning galvanometer 42 returns to the initial voltage value, and the lens of the one-dimensional scanning galvanometer 42 returns to its initial position. The driving signal for the MEMS galvanometer 41 is a square wave with a period of T, where the high-level time is t1 and the low-level time is t2. The period and duty cycle can be set by the signal generator 6 to ensure that the voltage and time controlled by the position of the MEMS galvanometer 41 that is in the light transmission position are synchronized with the exposure signal of the area scan camera 51.

[0078] In summary, as Figure 2 Figure 3 and Figure 4 As shown, this embodiment provides a line-scan spectral optical coherence tomography system. The principle optical path for imaging low-scattering or high-absorption sample tissues in the yz and xz planes is as follows: Light emitted from a high-power broadband light source 11 passes through a spectral filter 12 and is then expanded by a 4F system composed of two cemented doublet lenses (a first cemented doublet convex lens 131 and a second cemented doublet convex lens 132) with specific focal lengths. The light then passes through a cylindrical mirror 14. In the reference arm 3, the light first passes through a neutral density filter 31 to reduce its power, and then is reflected by a first planar mirror 33. In the sample arm 4, the light is first reflected by a MEMS galvanometer 41, then reflected to a one-dimensional scanning galvanometer 42, and then reflected again by a planar mirror and focused onto the sample tissue surface by a second microscope objective 43. The drive signal of MEMS galvanometer 41 is synchronized with the exposure signal of 2D area array camera 51: it remains stationary during the exposure time of area array camera 51, and the optical path of sample arm 4 is open; after the exposure ends, MEMS galvanometer 41 deflects at a small angle and maintains its state, and the optical path of sample arm 4 is cut off. The light returning from reference arm 3 and sample arm 4 interferes, and in the optical path of signal detection device 5, a 4F system composed of two cemented doublet lenses (fourth cemented doublet convex lens 521 and fifth cemented doublet convex lens 522) with specific focal lengths is used for beam contraction. Stray light is filtered out by slit aperture 523 and finally illuminates the surface of grating 53.

[0079] In the yz plane, the light beam propagates parallel along the z direction, is focused on the sample tissue surface by the second microscope objective 43, and the backscattered light from the sample tissue is propagated parallel again by the second microscope objective 43. Figure 4Between the two second microscope objectives 43 is the sample tissue. After the beam is compressed by the 4F system consisting of the fourth cemented doublet 521 and the fifth cemented doublet 522, the spot size is modulated. The slit aperture 523 simultaneously blocks stray light. The (diffraction) grating 53 (which disperses the light according to different wavelengths) and the third cemented doublet 54 focus the dispersive spectrum of the beam (forming a multi-colored linear spot after focusing) onto the (two-dimensional) area array camera 51 (the two-dimensional area array camera is a global camera). The area array camera 51 collects all the data. A focused wavelength light spot is generated. In the xz plane, the beam propagates along the z-direction. After passing through cylindrical mirror 14, the light spot is focused. Following the beam splitter 2, the fourth cemented doublet 521, the slit aperture 523, and the fifth cemented doublet 522, the beam is dispersed by grating 53 and broadened by the third cemented doublet 54. Area array camera 51 collects all light spots in the x-direction. Combining this with the transverse spectral information, a fast Fourier transform is performed to obtain the xz plane cross-sectional image. This improves the utilization rate of ineffective light without damaging the sample tissue due to photothermal effects. The y-axis direction is perpendicular to the paper and inwards, while the z-axis direction is the direction of the beam emitted from light source 1.

[0080] Example 2

[0081] This embodiment provides a line-scan spectral optical coherence tomography device, including the line-scan spectral optical coherence tomography system as described in Embodiment 1.

[0082] For a more detailed description of the working process of the above imaging system, please refer to the relevant content disclosed in Embodiment 1, which will not be repeated here.

[0083] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A line-scan spectral optical coherence tomography system, characterized in that, include: A light source generating device used to emit a light beam; A beam splitter is located at an extension of the beam emission direction of the light source generator and is used to split the beam emitted by the light source generator into a first beam and a second beam. A reference arm, located in the optical path of the first beam, is used to receive the first beam emitted by the beam splitter and reflect the first beam back to the beam splitter. The sample arm, located in the optical path of the second beam, is used to receive the second beam emitted by the spectrometer and irradiate the sample tissue with the second beam. The backscattered light carrying sample tissue information returns to the spectrometer along the original path. The sample arm includes a MEMS galvanometer and a one-dimensional scanning galvanometer. The MEMS galvanometer is located in the optical path of the second beam. The MEMS galvanometer can be deflected at an angle. When the MEMS galvanometer is not deflected, the second beam is reflected by the MEMS galvanometer and incident on the one-dimensional scanning galvanometer, the optical path is open, and the sample tissue receives illumination. When the MEMS galvanometer is deflected, the second beam is reflected by the MEMS galvanometer and deflected out of the one-dimensional scanning galvanometer, the optical path is cut off, and the sample tissue does not receive illumination. The beam splitter is also used to receive the reflected light from the reference arm and the backscattered light from the sample arm carrying sample tissue information. The two beams interfere with each other within the beam splitter to form interference light. The signal detection device is set in the opposite direction to the initial emission direction of the first beam. It is used to decompose the interference light into interference spectral signals and convert the interference spectral signals into electrical signals and transmit them to the computer. The computer uses a Fourier transform algorithm to process and reconstruct the sample tissue image. The signal detection device includes an area array camera, which is used to convert the interference spectral signal into an electrical signal and transmit it to a computer. A signal generator, electrically connected to the MEMS galvanometer, the one-dimensional scanning galvanometer, and the area array camera, is used to generate the deflection timing of the MEMS galvanometer, the scanning voltage stepping timing of the one-dimensional scanning galvanometer, and the shooting timing of the area array camera. The MEMS galvanometer deflection timing and the scanning timing of the one-dimensional scanning galvanometer are set synchronously based on the shooting timing of the area array camera. During the exposure time of the area array camera, the MEMS galvanometer timing remains at a low level and does not deflect, the optical path of the sample arm is open, and the sample tissue receives the light signal; after the exposure of the area array camera ends, the MEMS galvanometer timing becomes a high level, driving the MEMS galvanometer to deflect at a small angle, the light is reflected out of the sample arm, and the optical path of the sample arm is cut off.

2. The line-scanning spectral optical coherence tomography system according to claim 1, characterized in that, The light source generating device includes: A broadband light source is used to generate the first low-coherence light; A spectral filter, located in the optical path of the first low-coherence light, is used to filter the first low-coherence light within the target spectral range to obtain the second low-coherence light; The beam-expanding lens group is located in the optical path of the second low-coherence light and is used to expand the second low-coherence light to obtain the third low-coherence light; A cylindrical mirror, located in the optical path of the third low-coherence light, is used to convert the third low-coherence light into a linear light spot.

3. The line-scanning spectral optical coherence tomography system according to claim 2, characterized in that, The beam-expanding lens group includes a first cemented doublet convex lens and a second cemented doublet convex lens arranged coaxially.

4. The line-scanning spectral optical coherence tomography system according to claim 1, characterized in that, The reference arm includes: A neutral density filter is located in the optical path from which the first beam is emitted by the beam splitter, and is used to reduce the optical power of the first beam; The first microscope objective is located on the side of the neutral density filter away from the beam splitter, and is used to receive the light emitted by the neutral density filter and illuminate the first plane mirror with the received light. The first plane mirror is located in the light-emitting direction of the first microscope objective and is used to reflect the received first light beam to the neutral density filter. The neutral density filter is also used to transmit the received reflected light to the beam splitter.

5. The line-scanning spectral optical coherence tomography system according to claim 1, characterized in that, The sample arm also includes: The second microscope objective is located in the light-emitting direction of the one-dimensional scanning galvanometer and is used to receive the light emitted by the one-dimensional scanning galvanometer and irradiate the sample tissue with the received light. The second microscope objective is also used to receive the backscattered light carrying the sample tissue information; The one-dimensional scanning galvanometer is also used to receive backscattered light carrying sample tissue information transmitted through the second microscope objective, and to transmit the backscattered light carrying sample tissue information back to the spectrometer through the MEMS galvanometer.

6. The line-scanning spectral optical coherence tomography system according to claim 1, characterized in that, The signal detection device further includes: A beam-constricting lens group is located in the optical path of the interference light emitted from the beam splitter and is used to reduce the interference light beam. A grating, located in the optical path of the beam-contracted interference light, is used to split the beam-contracted interference light to obtain interference light of different wavelengths; The third doublet convex lens is located in the optical path of interference light of different wavelengths and is used to focus interference light of different wavelengths onto a column of pixels of the area array camera.

7. The line-scan spectral optical coherence tomography system according to claim 6, characterized in that, The signal detection device also includes a second planar reflector, located on the optical path of the interference light emitted by the beam splitter, for changing the optical path of the interference light.

8. The line-scanning spectral optical coherence tomography system according to claim 6, characterized in that, The beam-constricting lens group includes a fourth cemented doublet convex lens and a fifth cemented doublet convex lens arranged coaxially; a slit stop is provided between the fourth cemented doublet convex lens and the fifth cemented doublet convex lens; the focal point of the fourth cemented doublet convex lens is located within the slit of the slit stop.

9. The line-scanning spectral optical coherence tomography system according to claim 2, characterized in that, The broadband light source includes a broadband light source of light-emitting diodes or a broadband light source of superluminescent light-emitting diodes.

10. A line-scan spectral optical coherence tomography imaging device, characterized in that, Includes the line-scan spectral optical coherence tomography system as described in any one of claims 1-9.

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