CN221865639U - Fundus imaging system - Google Patents

Abstract

The utility model provides a fundus imaging system, comprising an optical circulator, an optical fiber coupler, a polarization controller, a data processing module, a reference arm and a sample arm. The utility model receives imaging optical signals and reference optical signals of a human fundus through a superluminescent diode, an optical circulator, an optical fiber coupler, a polarization controller, a reference arm and a sample arm, processes the difference optical signals through the data processing module to convert them into digital electrical signals, so that they are read by a computer, and images of fundus at various levels are generated and displayed. The optical circulator enables the light output by the superluminescent diode to be transmitted only to the optical fiber coupler, and the light returned from the optical fiber coupler to the optical circulator can be transmitted only to a detector D1, thereby improving the light use efficiency. Meanwhile, the polarization controller can adjust the polarization state of the light returned by the sample arm, so that the polarization states of the returned light of the sample arm and the reference arm are the same, thereby effectively enhancing the optical interference signal and improving the signal-to-noise ratio.

Description

Fundus imaging system

Technical Field

The utility model relates to the technical field of fundus imaging, in particular to a fundus imaging system.

Background Art

Fundus imaging is a medical examination method that uses optical equipment to observe and record the bottom of the eyeball. This imaging technology provides detailed information about the structure and pathology of the eye, which is very important for ophthalmologists to diagnose and plan treatment of eye diseases.

The Chinese invention patent with publication number CN203483396U discloses a fundus imaging device, which consists of a light source component, a scanning illumination optical path component, and a detection component. The fundus microscope device proposed in the invention uses a nested optical fiber to output a laser light source, and works through a two-dimensional imaging scanning galvanometer in the scanning illumination optical path component to illuminate the retina of the human eye and return to the nested optical fiber according to the original optical path, and finally enters the detection component, thereby obtaining a high-resolution image of the retina of the human eye. The invention nests the laser light source output fiber and the detector receiving fiber in the same optical fiber, which greatly saves system space, reduces the output power and cost of the laser, and realizes a fundus imaging device with compact design, high imaging resolution, high safety, and simple control, which greatly improves the system space and imaging quality of traditional fundus imaging instruments. However, its light source route is directly separated and coupled through a fiber coupler, which has a large loss, and it does not perform noise reduction processing on the electrical signal in the detector, resulting in a low signal-to-noise ratio of the overall system and poor imaging quality.

Utility Model Content

The purpose of the utility model is to provide a fundus imaging system to solve the problems raised in the above background technology.

In order to achieve the above purpose, the utility model provides the following technical solutions:

A fundus imaging system, comprising:

A superluminescent diode, wherein the superluminescent diode is connected to the optical circulator via an optical fiber and is used to emit low-coherence light;

An optical circulator, which is connected to the optical fiber coupler via an optical fiber and is used to complete the forward/reverse transmission separation task of low-coherence light;

An optical fiber coupler, which is connected to the polarization controller through an optical fiber and is used to transfer an optical signal from one optical fiber to another optical fiber to achieve coupling and transmission of the optical signal;

A polarization controller, which is connected to the reference arm and the sample arm through optical fibers, and is used to adjust the polarization state of light so that the polarization states of the return light from the sample arm and the reference arm are the same;

A data processing module, the data processing module is respectively connected to the optical circulator and the optical fiber coupler through optical fibers, and is used to convert the optical signal into an electrical signal, and perform conversion, filtering, and amplification processing on the electrical signal;

A reference arm, used to reflect an optical signal used as a reference;

Sample arm, used to reflect light signals for fundus imaging.

In one embodiment, the data processing module includes a photodetector D1, a photodetector D2, two I/V converters, two high-pass filters, and a differential amplifier, a bandpass filter, and a data acquisition card that are electrically connected in sequence, which are respectively used to convert a reference light signal into an electrical signal, convert a fundus imaging light signal into an electrical signal, perform current-to-voltage conversion on the electrical signal, filter out electrical signals other than high-frequency signals, amplify the difference between two input signals, filter out electrical signals within a specific frequency range, and convert electrical signals into digital signals. The photodetector D1, the I/V converter, and the high-pass filter are electrically connected in sequence, and the photodetector D2, the I/V converter, and the high-pass filter are electrically connected in sequence.

In one of the embodiments, the data acquisition card is connected to the cloud server via a data transmission unit signal.

In one of the embodiments, the central wavelength of the low coherence light is 1310 nm, the 3dB bandwidth of the spectrum is 45 nm, and the maximum output power is 7 mW.

In one embodiment, the reference arm is composed of a collimating objective lens, a grating, a total reflection mirror, a lens, and a fast scanning galvanometer.

In one embodiment, the sample arm is composed of a collimating objective lens, a converging lens, and a slow scanning galvanometer.

Compared with the prior art, the beneficial effects of the utility model are:

The utility model receives imaging optical signals of the fundus of the human eye and reference optical signals as references through a superluminescent diode, an optical circulator, an optical fiber coupler, a polarization controller, a reference arm, and a sample arm, processes the difference optical signals through a data processing module, converts them into digital electrical signals, and thus is read by a computer, generates and displays images of each level of the fundus, and because of the optical circulator, the light output by the superluminescent diode can only be transmitted to the optical fiber coupler, and the light returned from the optical fiber coupler to the optical circulator can only be transmitted to the detector D1, which increases the light use efficiency of the utility model, and at the same time, the polarization controller can adjust the polarization state of the light returned by the sample arm, so that the polarization states of the returned light of the sample arm and the reference arm are the same, thereby effectively enhancing the optical interference signal and improving the signal-to-noise ratio.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a system module diagram of the utility model;

FIG2 is a system module diagram of a data processing module of the present utility model;

FIG. 3 is a light path diagram of the reference arm and the sample arm of the present invention.

In the figure: 11, superluminescent diode; 12, optical circulator; 13, fiber coupler; 14, polarization controller; 15, reference arm; 16, sample arm; 20, data processing module; 21, photodetector D1; 22, photodetector D2; 23, I/V converter; 24, high-pass filter; 25, differential amplifier; 26, band-pass filter; 27, data acquisition card.

DETAILED DESCRIPTION

The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

Example:

Please refer to Figures 1 and 2, the utility model provides a technical solution:

A fundus imaging system, comprising:

The superluminescent diode 11 is connected to the optical circulator 12 through an optical fiber and is used to emit low-coherence light; if the light source is a coherent light source, then within the range of the axial displacement ΔL of the fast scanning galvanometer of the reference arm 15, both lights will interfere, and when the light source adopts a low-coherence light source, interference will only occur when the optical path difference between the reference arm 15 and the sample arm 16 is less than or equal to the coherence length. The utility model adopts a low-coherence light source, and through the axial movement of the fast scanning galvanometer of the reference arm 15, it matches the optical path with the sample light, thereby obtaining an interference electrical signal with sample structure information. In order to emit low-coherence light with a central wavelength of 1310nm, a 3dB bandwidth of the spectrum of 45nm, and a maximum output power of 7mW, a superluminescent diode 11 is used.

The optical circulator 12 is connected to the fiber coupler 13 through an optical fiber, and is used to complete the forward/reverse transmission separation task of the low-coherence light; the fiber coupler 13 is connected to the polarization controller 14 through an optical fiber, and is used to transfer the optical signal from one optical fiber to another optical fiber to achieve the coupling and transmission of the optical signal; the low-coherence light is divided into two beams after passing through the optical circulator 12 and the fiber coupler 13, one beam is used as the reference light and is reflected back by the fast scanning galvanometer of the reference arm 15, and the other beam is used as the detection light, which passes through the polarization controller 14 and the scanning probe and is incident on the sample arm 16, that is, the human fundus, and the detection light is reflected back by tissues at different depths of the human fundus. Among them, the fiber coupler 13 is a 2X2 coupler structure with a splitting ratio of 50:50, which can make the DC components of the two split optical signals completely match, that is, the waveforms of the DC components of the two optical signals match, and their AC components differ in phase by 180°. After the two signals are differentiated, the DC part is suppressed and the AC part signal is strengthened, thereby reducing system noise and improving the signal-to-noise ratio. The optical circulator 12 can make the light output by the superluminescent diode 11 be transmitted to the fiber coupler 13, and the light returned from the fiber coupler 13 to the optical circulator 12 can be transmitted to the photodetector D121, thereby improving the light utilization efficiency of the utility model. The models of the photodetector D121 and the photodetector D222 are both OE-200-UV photodetector, the model of the I/V converter 23 is A4-P1-O4 analog I/V signal converter, the model of the high-pass filter 24 is HFCN-5500+, the model of the differential amplifier 25 is AD629BRZ, the model of the band-pass filter 26 is BF1608-L2R4DAAT, and the model of the data acquisition card 27 is FCFR-USB2027.

The polarization controller 14 is connected to the reference arm 15 and the sample arm 16 respectively through optical fibers, and is used to adjust the polarization state of light so that the polarization states of the return light from the sample arm 16 and the reference arm 15 are the same; the polarization controller 14 can adjust the polarization state of the return light from the sample arm 16 so that the polarization states of the return light from the sample arm 16 and the reference arm 15 are the same, thereby effectively enhancing the optical interference signal and improving the signal-to-noise ratio.

The data processing module 20 is respectively connected to the optical circulator 12 and the optical fiber coupler 13 through optical fibers, and is used to convert the optical signal into an electrical signal, and convert, filter, and amplify the electrical signal; the data processing module 20 includes a photodetector D121, a photodetector D222, two I/V converters 23, two high-pass filters 24, and a differential amplifier 25, a bandpass filter 26, and a data acquisition card 27 that are electrically connected in sequence, and are respectively used to convert the reference optical signal into an electrical signal, convert the fundus imaging optical signal into an electrical signal, perform current-voltage conversion on the electrical signal, filter out the electrical signal other than the high-frequency signal, amplify the difference between the two input signals, filter out the electrical signal in a specific frequency range, and convert the electrical signal into a digital signal. The photodetector D121, the I/V converter 23, and the high-pass filter 24 are electrically connected in sequence, and the photodetector D222, the I/V converter 23, and the high-pass filter 24 are electrically connected in sequence. The returned reference light signal and the returned sample light signal are coupled and divided into two beams after interference through the optical fiber coupler 13. One beam of light passes through the optical circulator 12 to the photodetector D121, and the other beam directly reaches the photodetector D222. The photodetector D121 and the photodetector D222 convert the two light signals into analog electrical signals, which are respectively passed through the I/V converter 23, the high-pass filter 24, the differential amplifier 25, and the band-pass filter 26. That is, after current-voltage conversion, high-pass filtering, differential amplification, and band-pass filtering, the DC component irrelevant to the information is removed, and an analog signal reflecting the layered structure information of the sample is obtained. The analog signal is then converted into a digital signal through the data acquisition card 27 and input into the cloud server. After being read by the computer, the image of the fundus is obtained and displayed after being processed using software.

The reference arm 15 is used to reflect the optical signal used as a reference; the reference arm 15 is composed of a collimating lens, a grating, a total reflection mirror, a lens, and a fast scanning galvanometer. The fast scanning galvanometer is an optical element used to quickly adjust the direction or position of a light beam. After the reference light enters the reference arm 15 from the optical fiber, it passes through the collimating lens, the grating, the lens, the fast scanning galvanometer, the lens, the grating, and the total reflection mirror in sequence.

The sample arm 16 is used to reflect the optical signal of fundus imaging; the sample arm 16 is composed of a collimating lens, a converging lens, and a slow scanning galvanometer. The slow scanning galvanometer is an optical element used to slowly and accurately adjust the direction or position of a light beam. After the sample light enters the sample arm 16 from the optical fiber, it passes through the collimating lens, the slow scanning galvanometer, the converging lens, and the fundus of the human eye in sequence.

Furthermore, the data acquisition card 27 is connected to the cloud server through a data transmission unit signal. The computer can read the processed digital signal through the cloud server. The data transmission unit is a G340DTU, which can transmit data through wireless data.

The working principle of the utility model is as follows: low coherent light is divided into two beams after passing through the optical circulator 12 and the fiber coupler 13. One beam is used as reference light and is reflected back by the fast scanning galvanometer of the reference arm 15. The other beam is used as detection light and is incident on the sample arm 16, i.e., the fundus of the human eye, after passing through the polarization controller 14 and the scanning probe. The detection light is reflected back by tissues at different depths of the fundus of the human eye. The returned reference light signal and the returned sample light signal are coupled and divided into two beams after interference through the fiber coupler 13. One beam of light passes through the optical circulator 12 to the photodetector D121, and the other beam directly to the photodetector D2 22, the photodetector D121 and the photodetector D222 convert the two beams of light signals into analog electrical signals, and pass through the I/V converter 23, the high-pass filter 24, the differential amplifier 25, and the bandpass filter 26 respectively, that is, after current-voltage conversion, high-pass filtering, differential amplification, and bandpass filtering, the DC component irrelevant to the information is removed, and an analog signal reflecting the layered structure information of the sample is obtained, and then converted into a digital signal by the data acquisition card 27 and input into the cloud server, and after being read by the computer, the image of the fundus is obtained and displayed after being processed by software. In the utility model, the light circulator 12 allows the light output by the superluminescent diode 11 to be transmitted only to the optical fiber coupler 13, and the light returned from the optical fiber coupler 13 to the light circulator 12 can only be transmitted to the detector D121, which increases the light use efficiency of the utility model, and at the same time, the polarization controller 14 can adjust the polarization state of the return light of the sample arm 16, so that the polarization state of the return light of the sample arm 16 and the reference arm 15 is the same, so that the optical interference signal is effectively enhanced and the signal-to-noise ratio is improved.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims (6)

1. A fundus imaging system, comprising: A superluminescent diode, wherein the superluminescent diode is connected to the optical circulator via an optical fiber and is used to emit low-coherence light; An optical circulator, which is connected to the optical fiber coupler via an optical fiber and is used to complete the forward/reverse transmission separation task of low-coherence light; An optical fiber coupler, which is connected to the polarization controller through an optical fiber and is used to transfer an optical signal from one optical fiber to another optical fiber to achieve coupling and transmission of the optical signal; A polarization controller, which is connected to the reference arm and the sample arm through optical fibers, and is used to adjust the polarization state of light so that the polarization states of the return light from the sample arm and the reference arm are the same; A data processing module, the data processing module is respectively connected to the optical circulator and the optical fiber coupler through optical fibers, and is used to convert the optical signal into an electrical signal, and perform conversion, filtering, and amplification processing on the electrical signal; A reference arm, used to reflect an optical signal used as a reference; Sample arm, used to reflect light signals for fundus imaging. 2. A fundus imaging system according to claim 1, characterized in that: the data processing module includes a photodetector D1, a photodetector D2, two I/V converters, two high-pass filters, and a differential amplifier, a bandpass filter, and a data acquisition card that are electrically connected in sequence, which are respectively used to convert a reference light signal into an electrical signal, convert a fundus imaging light signal into an electrical signal, perform current-voltage conversion on the electrical signal, filter out electrical signals other than high-frequency signals, amplify the difference between two input signals, filter out electrical signals within a specific frequency range, and convert electrical signals into digital signals; the photodetector D1, the I/V converter, and the high-pass filter are electrically connected in sequence; and the photodetector D2, the I/V converter, and the high-pass filter are electrically connected in sequence. 3. A fundus imaging system according to claim 2, characterized in that: the data acquisition card is connected to the cloud server via a data transmission unit signal. 4. A fundus imaging system according to claim 1, characterized in that: the central wavelength of the low-coherence light is 1310nm, the 3dB bandwidth of the spectrum is 45nm, and the maximum output power is 7mW. 5. A fundus imaging system according to claim 1, characterized in that: the reference arm is composed of a collimating objective lens, a grating, a total reflection mirror, a lens, and a fast scanning galvanometer. 6 . The fundus imaging system according to claim 1 , wherein the sample arm is composed of a collimating objective lens, a converging lens, and a slow scanning galvanometer.