CN-122004743-A - Multi-band adjustable scanning laser ophthalmoscope fundus imaging optical system and method

Abstract

The invention belongs to the technical field of optical imaging systems. The optical path sequentially comprises a wide-spectrum light source, a collimating lens, a refraction type grating, a focusing lens, an adjustable slit device, a collimator and a light source coupling optical fiber, wherein the wide-spectrum light source is used for providing continuous spectrum, a linear spectrum image is formed on a focal plane through grating dispersion and the focusing lens, the adjustable slit device is positioned on the focal plane, four independent slit units are controlled through a movable plate and a push rod, one to four target wave bands can be dynamically intercepted, and each selected wave beam is collimated by the collimator and then is coupled into a single optical fiber in a common fiber mode for output. The multi-mode fundus synchronous imaging device ensures the efficient collection and common fiber transmission of multi-band light through strict optical design constraint, and realizes multi-mode fundus synchronous imaging with compact structure, flexible and adjustable wave band and coaxial illumination.

Inventors

• SONG WEIYE
• ZHAO YIXIANG
• WEI HONGTAO
• XU GUODONG
• YANG HAOHUA
• ZHANG SUHANG
• ZHOU LIBO
• CUI YUAN
• QI MIN

Assignees

• 山东大学

Dates

Publication Date

20260512

Application Date

20260413

Claims (14)

1. 1. The multi-band adjustable scanning laser ophthalmoscope fundus imaging optical system is characterized by comprising a wide-spectrum light source, a collimating lens, a grating, a focusing lens, an adjustable slit device, a collimator and a light source coupling optical fiber which are sequentially arranged along an optical path; The broad spectrum light source is used for emitting continuous spectrum light beams; the collimating lens is arranged on the light emitting side of the wide-spectrum light source and is used for converting divergent light beams emitted by the wide-spectrum light source into parallel light beams; the grating is a refraction grating and is arranged on the emergent side of the collimating lens and used for dispersing the parallel light beams; The focusing lens is arranged on the emergent side of the grating and is used for forming spectral images which are linearly distributed according to the wavelength on the focal plane of each wavelength component after the chromatic dispersion of the grating; the adjustable slit device is arranged at the focal plane of the focusing lens, and is provided with four independently controllable slit units for intercepting one to four discrete target wave band lights in the spectrum image at the same time; the collimator is arranged on the emergent side of the adjustable slit device and is used for receiving and collimating the light of each target wave band passing through the slit unit; the light source coupling optical fiber is arranged on the emergent side of the collimator and is used for coupling the light of each collimated target wave band into the same optical fiber to be output as a multiband common-fiber illumination light source.
2. 2. The multi-band tunable scanning laser ophthalmoscope fundus imaging optical system of claim 1, wherein, The incidence angle of the grating is equal to the diffraction angle corresponding to the central wavelength of the wide-spectrum light source.
3. 3. The multi-band tunable scanning laser ophthalmoscope fundus imaging optical system of claim 1, wherein, The focal length of the focusing lens, the minimum wavelength and the maximum wavelength of the wide-spectrum light source, and the widths of two adjacent slits of the grating jointly determine the center distance of any two adjacent wavelengths in the spectrum image on the focal plane.
4. 4. The multi-band tunable scanning laser ophthalmoscope fundus imaging optical system of claim 1, wherein, The center distance of any two adjacent slit units in the adjustable slit device is equal to the center distance of the corresponding two wavelengths on the focal plane, and the center distance is the sum of the slit width and the slit distance.
5. 5. The multi-band tunable scanning laser ophthalmoscope fundus imaging optical system of claim 1, wherein, The distance between the collimator and the adjustable slit device is not more than the maximum allowable distance determined by the included angle between the light of the adjacent two target wave bands and the normal after exiting the adjustable slit device and the center distance between the light of the adjacent two target wave bands and the normal on the focal plane.
6. 6. The multi-band tunable scanning laser ophthalmoscope fundus imaging optical system of claim 1, wherein, The size of the collimator is smaller than or equal to the total width of transverse divergence determined by the maximum allowable distance and the included angle between the two adjacent rows of target wave band lights and the normal after the adjustable slit device is emergent.
7. 7. The multi-band tunable scanning laser ophthalmoscope fundus imaging optical system of claim 1, wherein, The adjustable slit device comprises a moving plate and four push rods, each push rod is connected with a stop block for shielding a corresponding slit unit, and the stop blocks are driven to move upwards by driving the push rods so as to release light in the slit.
8. 8. A multi-band tunable fundus imaging method using the multi-band tunable scanning laser ophthalmoscope fundus imaging optical system of any one of claims 1-7, comprising the following processes: turning on a wide spectrum light source to emit a continuous spectrum light beam; The light is converted into parallel light beams by a collimating lens and then is incident to a grating; dispersing the parallel light beam by using a grating; Forming a spectral image linearly distributed according to the wavelength on a focal plane of each dispersed wavelength component through a focusing lens; controlling a plurality of slit units in the adjustable slit device to be opened, and intercepting one to four discrete target wave band lights in a spectrum image at the same time; the light of each target wave band passing through the slit unit is coupled into the same light source coupling optical fiber after being collimated by the collimator, and is used as common-fiber multiband illumination light for fundus scanning imaging.
9. 9. The multi-band tunable fundus imaging method of claim 8, wherein, Before the adjustable slit device is controlled to open the slit unit, the position of each target wavelength on the focal plane is calculated according to the wavelength value of the target wave band, the dispersion relation of the grating and the focal length of the focusing lens, and the moving plate of the adjustable slit device is moved to the target slit position according to the position.
10. 10. The multi-band tunable fundus imaging method of claim 8, wherein, The step of controlling the adjustable slit device to open the slit unit comprises driving a moving plate of the adjustable slit device to move to a region containing all target wave band positions, respectively driving push rods corresponding to all target wave bands, enabling a stop block for shielding the slit unit to move upwards, and discharging the light source in the slit.
11. 11. The multi-band tunable fundus imaging method of claim 8, wherein, The multi-band illumination light coupled into the light source coupling optical fiber is led into the scanning module of the scanning laser ophthalmoscope to synchronously scan the fundus, the fundus reflected light is received, and the reflected light of different wave bands is separated to the corresponding detector through the light splitting module to generate fundus images of each wave band.
12. 12. The multi-band tunable fundus imaging method of claim 8, wherein, The light splitting cut-off wavelength of each light splitting element in the light splitting module is set according to the wavelength interval between the selected target wave bands, so that effective isolation of light of each wave band is realized.
13. 13. The multi-band tunable fundus imaging method of claim 8, wherein, Before coupling the multi-band light into the light source coupling fiber, it is checked whether the actual distance between the collimator and the adjustable slit arrangement meets a maximum allowed spacing condition determined by the exit angle and the focal plane spacing of the light of adjacent target bands.
14. 14. The multi-band tunable fundus imaging method of claim 8, wherein, Support to dynamically switch different target band combinations during a single inspection, the switching operation being accomplished by reconfiguring the motion state of the push rod in the adjustable slit device.

Description

Multi-band adjustable scanning laser ophthalmoscope fundus imaging optical system and method Technical Field The invention relates to the technical field of optical imaging systems, in particular to a multi-band adjustable scanning laser ophthalmoscope fundus imaging optical system and a multi-band adjustable scanning laser ophthalmoscope fundus imaging method. Background The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art. In the field of fundus imaging, scanning laser ophthalmoscopes (SCANNING LASER Ophthalmoscope, SLO) have become an important tool for clinical diagnosis of retinal diseases due to their high contrast, high resolution, and non-invasiveness. Conventional SLO systems typically employ a single fixed wavelength laser as the illumination source, e.g., 488 nanometers for viewing the retinal nerve fiber layer, 532 nanometers for enhancing vascular contrast, or 790 nanometers for penetrating into the deep choroidal structures. Along with the improvement of the multi-mode fundus information fusion requirement, researchers gradually introduce a multi-band imaging technology, and complementary structural and functional information is obtained through the selective response of different wavelength lights to fundus tissues. Early implementations relied on multiple independent laser combinations, in combination with complex optical path switching or beam combining devices, to support multi-wavelength illumination. Although the scheme can realize multi-spectrum imaging, the system has complex structure, huge volume and high cost, and the strict synchronization of the light of each wavelength in space and time is difficult to ensure, so that the application of the system in portable or integrated equipment is limited. Existing SLO systems have significant limitations in achieving multi-band illumination. The adoption of a plurality of discrete lasers leads to large system volume and high cost, and the optical axes of the light sources are difficult to completely coincide, so that the illumination areas of different wave bands are offset, and the spatial consistency of the multiband images is affected. The mode of adopting the filter wheel to be matched with the broadband light source can reduce the number of the light sources, but the band switching speed is low, multi-band synchronous illumination cannot be realized, only one band is allowed to pass through each time, and the imaging efficiency and the flexibility are limited. In addition, it is difficult to output multiple discrete bands simultaneously in the same illumination path in the prior art, resulting in multiple scans or complex optical path reorganization required for multi-modal imaging. These problems make the current system have shortcomings in the aspects of band configuration flexibility, imaging synchronism, structural compactness, clinical applicability and the like, and restrict the further popularization and application of the multiband SLO technology. Disclosure of Invention In order to solve the defects of the prior art, the invention provides a multi-band adjustable scanning laser ophthalmoscope fundus imaging optical system and a multi-band adjustable scanning laser ophthalmoscope fundus imaging optical method, which can realize SLO (selective laser beam) detection imaging at any 1-4 bands, a broad-spectrum light source is firstly converted into parallel light through a lens, then the parallel light is split by a grating, the light separated by different bands is focused on an adjustable slit, the adjustable slit controls any 1-4 slits to open and close, and 1-4 target band light sources are emitted into a collimator. The light entering the collimator is coupled into the light source coupling fiber again, and finally exits as a light source of the SLO. In order to achieve the above purpose, the present invention adopts the following technical scheme: in a first aspect, the present invention provides a multi-band tunable scanning laser ophthalmoscope fundus imaging optical system. A multi-band adjustable scanning laser ophthalmoscope fundus imaging optical system comprises a wide-spectrum light source, a collimating lens, a grating, a focusing lens, an adjustable slit device, a collimator and a light source coupling optical fiber which are sequentially arranged along an optical path; The wide-spectrum light source is used for emitting continuous spectrum light beams; The collimating lens is arranged on the light emitting side of the broad spectrum light source and is used for converting divergent light beams emitted by the broad spectrum light source into parallel light beams; the grating is a refraction grating and is arranged on the emergent side of the collimating lens and used for dispersing the parallel light beams; the focusing lens is arranged on the emergent side of the grating and is used for forming a spectral image which is l