Optical system of handheld OCT equipment and handheld OCT equipment

Abstract

The invention provides an optical system of handheld OCT equipment and the handheld OCT equipment. The optical system of the handheld OCT equipment comprises a galvanometer, a light beam adjusting set and a light beam focusing set which are sequentially arranged from a light source to human eyes. The focal length ratio of the focal length of the light beam adjusting group to the focal length of the light beam focusing group meets the following relational expression: 1lt; a focal length ratio lt; 1.2; the galvanometer is used for scanning the light rays emitted by the light source to the light beam adjusting group so as to generate light beams; the light beam adjusting group is used for adjusting the propagation direction and divergence of the light beam emitted by the galvanometer; and the light beam focusing group is used for focusing the light beam adjusted by the light beam adjusting group to the human eye, so that the light beam is imaged at the retina of the human eye. In the mode, by optimizing the design of the optical system, the handheld OCT equipment can better adapt to the eye axis length and the pupil size of the infant, and the fundus imaging quality of ophthalmic examination of 0-3-year-old infants is improved.

Description

Technical Field

[0001] The present application relates to the field of optical detection technology, and in particular to an optical system of a handheld OCT device and a handheld OCT device. Background Art

[0002] In recent years, OCT (Optical Coherence Tomography) has been widely used in ophthalmic examinations because it can provide high-resolution fundus imaging and has the advantages of being non-invasive and fast. Traditional desktop OCT devices are large in size, require patients to maintain a fixed posture (such as sitting or standing), and require the use of devices such as chin rests to maintain head stability, which limits their application scenarios, especially for the detection of infants and supine patients. With the continuous development of miniaturized optical components, handheld OCT devices have emerged, greatly improving the portability and applicability of the equipment.

[0003] At present, the demand for eye examinations for infants aged 0-3 years is increasing. However, existing OCT devices are mostly designed for adults and are difficult to meet the adaptability requirements of infants' axial length and pupil diameter differences, thus affecting the imaging quality and examination efficiency. To solve this problem, the present invention provides a handheld OCT device that can better adapt to the axial length and pupil size of infants and improve the quality of fundus imaging by optimizing the optical system design. Summary of the invention

[0004] In view of this, the purpose of the present application is to provide an optical system for a handheld OCT device and a handheld OCT device. By optimizing the optical system design, the handheld OCT device can better adapt to the axial length and pupil size of infants and young children, thereby improving the fundus imaging quality of ophthalmic examinations of infants and young children aged 0-3 years old.

[0005] In a first aspect, the present invention provides an optical system of a handheld OCT device, comprising: a galvanometer, a beam adjustment group and a beam focusing group are arranged in sequence from a light source to a human eye; a focal length ratio between the focal length of the beam adjustment group and the focal length of the beam focusing group satisfies the following relationship: 1<focal length ratio<1.2; a galvanometer, used to scan light emitted by the light source to the beam adjustment group to generate a light beam; the beam adjustment group, used to adjust the propagation direction and divergence of the light beam emitted by the galvanometer; and a beam focusing group, used to focus the light beam adjusted by the beam adjustment group to the human eye so that the light beam is imaged at the retina of the human eye.

[0006] In an optional embodiment, the beam adjustment group includes a second lens; the second lens is connected to a motor; the beam adjustment group and the beam focusing group share a common optical axis; the distance between the second lens and the beam focusing group is a moving distance, and the moving distance satisfies the following relationship: 8mm≤moving distance≤25mm; the second lens is controlled by a motor to move along the optical axis based on the moving distance to adapt to human eyes with different axial lengths; the axial length satisfies the following relationship: 19mm≤axial length≤23mm.

[0007] In an optional embodiment, the beam focusing group is a third lens; the first surface and the second surface of the third lens are both aspherical surfaces; the third focal length of the third lens satisfies the following relationship: 24.4mm<third focal length<25.2mm; the distance between the third lens and the galvanometer is a first distance, and the first distance satisfies the following relationship: 95mm<first distance<115mm; the distance between the third lens and the human eye is a second distance; the distance ratio between the first distance and the second distance satisfies the following relationship: 0.17≤distance ratio≤0.22.

[0008] In an optional embodiment, the beam adjustment group includes a first lens and a second lens arranged in sequence from the galvanometer to the beam focusing group; the first lens is used to focus the beam; and the second lens is used to adjust the propagation direction and divergence of the focused beam.

[0009] In an optional embodiment, the first lens is a cemented lens, and the second lens is a meniscus lens; the surface of the second lens close to the first lens is aspherical; the first focal length of the first lens satisfies the following expression: 42mm<first focal length<44mm; the second focal length of the second lens satisfies the following expression: 55mm<second focal length<60mm.

[0010] In an optional embodiment, a dichroic mirror is arranged between the beam adjustment group and the beam focusing group; the beam adjustment group, the dichroic mirror and the beam focusing group share a common optical axis; the dichroic mirror is at 45° to the optical axis; the dichroic mirror is used to transmit a light beam within a first wavelength band range; the first wavelength band range is 820nm≤beam wavelength≤1150nm.

[0011] In an optional embodiment, the optical system also includes a pupil lens and a detector; the pupil lens is arranged below the dichroic mirror; the detector is arranged on the side of the pupil lens close to the light source; the dichroic mirror is also used to receive the return light returned by the human eye, and reflect the return light within the second wavelength band to the pupil lens, so that the return light passes through the pupil lens to reach the detector; the second wavelength band is 700nm≤return light wavelength≤800nm; the detector is used to generate an OCT image corresponding to the human eye based on the return light.

[0012] In an optional embodiment, the third distance between the galvanometer and the beam adjustment group is 20 mm.

[0013] In a second aspect, the present invention provides a handheld OCT device, comprising a light source; and also comprising the optical system of the handheld OCT device of any one of the aforementioned embodiments; the light source is arranged on a side of the optical system of the handheld OCT device away from the human eye.

[0014] In an optional embodiment, the light source includes a scanning light source and an illumination light source; the scanning light source is infrared light, the operating wavelength range of the scanning light source is 1060nm-1150nm, and the center wavelength is 1060nm; the illumination light source is visible light, and the operating wavelength range of the illumination light source is 820-860nm.

[0015] The embodiment of the present application provides an optical system of a handheld OCT device and a handheld OCT device, including: a galvanometer, a beam adjustment group and a beam focusing group are arranged in sequence from the light source to the human eye; the focal length ratio between the focal length of the beam adjustment group and the focal length of the beam focusing group satisfies the following relationship: 1<focal length ratio<1.2; the galvanometer is used to scan the light emitted by the light source to the beam adjustment group to generate a light beam; the beam adjustment group is used to adjust the propagation direction and divergence of the light beam emitted by the galvanometer; the beam focusing group is used to focus the light beam adjusted by the beam adjustment group to the human eye so that the light beam is imaged at the retina of the human eye. By optimizing the optical system design of the handheld OCT device, the optical system of the handheld OCT device can automatically adjust the settings of the optical elements according to the different axial lengths and pupil diameters of infants and young children. By accurately controlling the propagation direction and divergence of the light beam, it is ensured that the light beam can be accurately focused on the fundus of the infant and young children, avoiding imaging distortion caused by axial differences. Furthermore, handheld OCT devices not only provide higher image resolution, but can also easily complete fundus imaging without the need to maintain a fixed posture, thereby improving the early screening and diagnosis of eye diseases in infants and young children.

[0016] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or understood by practicing the present application. The purpose and other advantages of the present application are realized and obtained by the structures specifically pointed out in the description, claims and drawings.

[0017] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 A schematic diagram of an optical system of a handheld OCT device provided in an embodiment of the present invention;

[0020] Figure 2 A structural diagram of an optical system provided by an embodiment of the present invention;

[0021] Figure 3 A schematic diagram of surface marking of an optical system provided by an embodiment of the present invention;

[0022] Figure 4 A point diagram of structure G1 in the first optical system design parameters provided by an embodiment of the present invention;

[0023] Figure 5 A point diagram of structure G2 in the first optical system design parameters provided by an embodiment of the present invention;

[0024] Figure 6 A point diagram of structure G3 in the first optical system design parameters provided by an embodiment of the present invention;

[0025] Figure 7 A point diagram of structure G1 in the second optical system design parameters provided by an embodiment of the present invention;

[0026] Figure 8 A point diagram of structure G2 in the second optical system design parameters provided by an embodiment of the present invention;

[0027] Fig. 9 A point diagram of structure G3 in the second optical system design parameters provided by an embodiment of the present invention;

[0028] Fig.10 A point diagram of structure G1 in the third optical system design parameters provided by an embodiment of the present invention;

[0029] Fig.11 A point diagram of structure G2 in the third optical system design parameters provided by an embodiment of the present invention;

[0030] Fig.12 A point diagram of structure G3 in the third optical system design parameters provided by an embodiment of the present invention;

[0031] Fig.13 A schematic diagram of a handheld OCT device provided in an embodiment of the present invention.

[0032] Icon: G100-galvanometer; Q1-beam adjustment group; Q2-beam focusing group; L1-first lens; L2-second lens; L3-third lens; L4-pupil lens; G300-dichroic mirror; G200-human eye; G400-detector; 1-light source; 2-optical system of handheld OCT device. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution of the present application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0034] Traditional desktop OCT systems, limited by their own physical structure, require patients to stand or sit when used for ophthalmic imaging, and they have to use equipment such as chin rests and headrests to maintain head stability. As a result, it is difficult to perform imaging operations on patients who are lying on their backs or under anesthesia. However, with the continuous development of miniaturized optical components, more compact OCT systems have gradually come into being. Against this background, handheld OCT came into being. The emergence of handheld OCT technology is of great significance. It enables patients to be imaged smoothly even when they are lying on their backs, and is especially suitable for detecting eye diseases in infants and young children.

[0035] At present, more and more attention is paid to the examination of eye diseases in infants and young children aged 0-3 years old. Active screening and early detection are the prerequisites for cure. At present, the integrated OCT equipment is more applicable to the human pupil diameter of 4-6mm. The pupil diameter of the eyes of infants and young children aged 0-3 years old is 2-3mm, and the axial length of the eyes of different age groups of 0-3 years old is also different. At present, there are few OCT devices designed for the eyes of infants and young children aged 0-3 years old on the market. The lack of targeting means that there will be some sacrifices, such as imaging resolution and inspection methods.

[0036] The optical system of the handheld OCT device provided in this application optimizes the design of the optical system so that the handheld OCT device can accurately adapt to the requirements of different axial lengths and pupil diameters of infants and young children, ensure high-quality fundus imaging, and thus provide a portable, accurate and efficient early screening solution, which is particularly suitable for ophthalmic examinations of infants and young children aged 0-3 years old.

[0037] To facilitate understanding of this embodiment, the embodiments of the present application are described in detail below.

[0038] Embodiment 1:

[0039] Figure 1 Schematic diagram of the optical system of the handheld OCT device provided in an embodiment of the present invention.

[0040] Reference Figure 1 The optical system of the handheld OCT device includes: a galvanometer G100, a beam adjustment group Q1 and a beam focusing group Q2 are arranged in sequence from the light source to the human eye G200; the focal length ratio between the focal length of the beam adjustment group Q1 and the focal length of the beam focusing group Q2 satisfies the following relationship: 1<focal length ratio<1.2.

[0041] The galvanometer G100 is used to scan the light emitted by the light source to the beam adjustment group Q1 to generate a light beam.

[0042] The beam adjustment group Q1 is used to adjust the propagation direction and divergence of the light beam emitted by the galvanometer G100.

[0043] The beam focusing group Q2 is used to focus the light beam adjusted by the beam adjusting group Q1 onto the human eye G200 so that the light beam forms an image at the retina of the human eye G200.

[0044] Here, the light source includes a scanning light source, which can be a frequency-sweeping laser, used to provide a basic scanning light for the optical system, usually infrared light, with an operating wavelength range of 1060-1150nm and a central wavelength of 1060nm. The wavelength is within the infrared band, and the human eye G200 is not sensitive to infrared light, which facilitates detection.

[0045] The galvanometer G100 can be a MEMS (Micro-Electro-Mechanical Systems) scanning galvanometer G100, which is located behind the light source and is responsible for controlling the angle and direction of the light so that the light can cover the entire scanning range of the fundus. The use of the MEMS scanning galvanometer G100 can greatly improve the acquisition speed of the optical system, improve the portability of the handheld OCT device, and help reduce the weight of the handheld OCT device, making it easier for the inspector to hold.

[0046] The scanning light source is transmitted to the human eye G200 through the galvanometer G100 through the optical system. The human eye G200 has a high reflectivity for infrared light, and part of the light is returned by the human eye G200. The returned light and the scanning light source form an interference signal, and finally form an OCT image.

[0047] The beam adjustment group Q1 is used to adjust the propagation direction and divergence of the light, providing appropriate beam conditions for the subsequent focusing group.

[0048] The beam focusing group Q2 accurately focuses the adjusted beam onto the human eye G200 to achieve high-resolution fundus imaging.

[0049] In order to meet the pupil diameter of infants and young children, the EPD (Entrance Pupil Diameter) range is controlled between 2mm and 3mm to match the pupil diameter of infants and young children, thereby avoiding light being blocked by the edge of the pupil and improving the imaging efficiency of the optical system.

[0050] Among them, the focal length fQ1 of Q1 is shorter and is used to preliminarily adjust the direction and divergence of the light, while the focal length fQ2 of Q2 is longer and is used to further converge and focus the light beam.

[0051] The focal length ratio between fQ1 and fQ2 satisfies the following relationship: The focal length ratio limited by the above relationship is conducive to ensuring that the vertical axis magnification of the optical system can meet the requirement that the Airy disk (imaging spot) of the optical system is small enough (less than 13um) under different axial lengths of the eye to meet the high-resolution imaging requirements. At the same time, based on the above focal length ratio, the galvanometer G100 with a small spot diameter is preferentially selected, thereby reducing the volume of the entire optical system, making the overall structure more compact, and facilitating the miniaturization and portability of the equipment.

[0052] In one embodiment, the optical system also includes a motor; the beam adjustment group Q1 includes a second lens L2; ​​the second lens L2 is connected to the motor; the beam adjustment group Q1 and the beam focusing group Q2 share a common optical axis; the distance between the second lens L2 and the beam focusing group Q2 is the moving distance, and the moving distance satisfies the following relationship: 8mm≤moving distance≤25mm.

[0053] Here, precise dynamic adjustment of the second lens L2 is achieved by a motor.

[0054] The beam adjustment group Q1 also includes the first lens L1. The distance between the first lens L1 and the beam focusing group Q2 is fixed. The motor drives the second lens L2 to perform fine adjustment along the optical axis. According to the requirements of different individual eye axis lengths, the relative position between the second lens L2 and the first lens L1 and the beam focusing group Q2 is adjusted (when the distance between the second lens L2 and the beam focusing group Q2 increases, the distance between the second lens L2 and the first lens L1 decreases accordingly) to ensure that the light beam can be accurately focused on the human eye G200. The motor can be a stepper motor or a servo motor, and is integrated with the control system to achieve high-precision adjustment.

[0055] The second lens L2 is connected to the motor through a mechanical component or an optical adjustment mechanism. The second lens L2 can be mounted on a movable platform or track, and the motor drives the platform through gears or linear drives to achieve precise movement of the lens group. This connection method ensures that the optical system maintains stability during the adjustment process, while ensuring the consistency of the optical axis between the beam adjustment group Q1 and the beam focusing group Q2. Among them, the optical elements of the beam adjustment group Q1 and the beam focusing group Q2 are designed on the same optical axis to ensure that the light does not deviate or error during propagation, avoiding beam loss or imaging distortion caused by optical axis offset.

[0056] The second lens L2 is controlled by a motor to move along the optical axis based on the moving distance to adapt to human eyes with different axial lengths; the axial length satisfies the following relationship: 19mm≤axial length≤23mm.

[0057] Here, the minimum movement distance is 8mm, which can ensure that the optical system can adapt to short axial lengths (19mm). The maximum movement distance is 25mm, which can ensure that the optical system can adapt to long axial lengths (23mm). The axial lengths of infants and young children of different ages vary greatly. Based on the above movement distance, the G200 can adapt to human eyes with different axial lengths to meet the needs of different refractive powers. The axial length satisfies the following relationship: 19mm≤axial length≤23mm, and at each axial length, the radius of the Airy spot is less than 13um, and the fundus scanning imaging diameter Y range satisfies 7mm≤Y≤10mm.

[0058] Specifically, the optical system calculates the required distance between the second lens L2 and the beam focusing group Q2 according to input parameters (such as the user's eye axis length), and the motor drives the mobile platform to adjust the distance between the second lens L2 and the beam focusing group Q2. After the movement is completed, the beam path is recalibrated to ensure that the light can be focused on the retina.

[0059] Figure 2 This is a structural diagram of an optical system provided in an embodiment of the present invention.

[0060] In one embodiment, referring to Figure 2 , the beam focusing group Q2 is the third lens L3; the first surface and the second surface of the third lens L3 are both aspherical surfaces; the third focal length of the third lens L3 satisfies the following relationship: 24.4mm<third focal length<25.2mm.

[0061] Here, the beam focusing group Q2 is the part of the optical system responsible for accurately focusing the adjusted light beam onto the human eye G200, which is specifically implemented as the third lens L3. The third lens L3 is an aspherical lens, and the third lens L3 has positive optical power and is a positive lens. An aspherical lens refers to a lens surface whose curvature is not a simple spherical curvature, but a curvature optimized according to specific needs. The first aspherical surface of the third lens L3 is used to preliminarily correct the divergence and spherical aberration of the light beam. The second aspherical surface of the third lens L3 is used to further adjust the focusing characteristics of the light beam to match the position of the retina of the fundus. By using an aspherical lens, it is ensured that the light beam can be accurately irradiated into the small pupil of the infant and focused on the retina after passing through the focusing group.

[0062] The smaller focal length (close to 24.4mm) of the third lens L3 helps to focus a shorter light beam, which is suitable for infants with short axial lengths. The larger focal length (close to 25.2mm) is suitable for infants with long axial lengths. The design range of the third focal length can ensure that the light beam can cover all axial length ranges while avoiding the impact of excessive or too small focal length on imaging quality. Among them, the radius of curvature of the third lens L3 is smaller than the radius of curvature of the side of the human eye G200.

[0063] Furthermore, the distance between the third lens L3 and the galvanometer G100 is a first distance, and the first distance satisfies the following relationship: 95mm<first distance<115mm; the distance between the third lens L3 and the human eye G200 is a second distance; the distance ratio between the first distance and the second distance satisfies the following relationship: 0.17≤distance ratio≤0.22.

[0064] Here, the first distance TTL1 is the distance between the galvanometer G100 and the third lens L3, wherein the first distance includes the thickness of the third lens L3. TTL1 directly affects the propagation path and convergence effect of the light beam. If it is too short, the light beam cannot be fully adjusted, and if it is too long, it may cause light loss or the system volume to be too large.

[0065] The design range of TTL1 is 95mm to 115mm. 95mm can ensure that the light beam has enough space for initial adjustment and convergence after being emitted from the galvanometer G100. 115mm can avoid the light beam dispersion caused by too long a distance, which affects the imaging effect.

[0066] The second distance TTL2 refers to the distance between the third lens L3 and the human eye G200. TTL2 is used to ensure that the light beam can accurately enter the pupil area of ​​the human eye G200 and finally focus on the retina. Through TTL2, the optical system is not directly close to the human eye G200, which improves the comfort of the person to be tested. Among them, the best effect is when TTL2 is 22mm.

[0067] The distance ratio between the first distance and the second distance satisfies the following relationship: When the ratio is not less than 0.17, it can ensure that the first distance is long enough and the light beam can remain stable during adjustment and focusing. When the ratio is not greater than 0.22, it can ensure that the second distance is short enough and the light beam can accurately enter the pupil area of ​​the human eye G200 and focus on the retina.

[0068] In one embodiment, referring to Figure 2 The beam adjustment group Q1 includes a first lens L1 and a second lens L2 which are sequentially arranged from the galvanometer G100 to the beam focusing group Q2.

[0069] The first lens L1 is used to focus the light beam.

[0070] The second lens L2 is used to adjust the propagation direction and divergence of the focused light beam.

[0071] Here, the light emitted by the galvanometer G100 first passes through the first lens L1 to preliminarily focus the light beam, and then the light beam passes through the second lens L2 to further adjust the propagation direction and divergence, and is optimized to be a light beam suitable for processing by the focusing group.

[0072] The first lens L1 is a positive lens having positive refractive power, and the second lens L2 is a negative lens having negative refractive power.

[0073] The combination of the beam adjustment group Q1 can be selected according to the actual situation, and can be a combination of a cemented lens (L1) and a meniscus lens (L2), or a combination of a single lens (L1) and a cemented lens (L2). Among them, when the first surface of the second lens L2 is an aspherical surface, the effect of the entire optical system is the best.

[0074] The third distance between the first lens L1 and the galvanometer G100 can be set to 20 mm, which is beneficial to reducing the divergence height of the light and making it easier to obtain a small-volume optical system.

[0075] In one embodiment, the first lens L1 is a cemented lens, and the second lens L2 is a meniscus lens; a surface of the second lens L2 close to the first lens L1 is an aspherical surface.

[0076] The first focal length of the first lens L1 satisfies the following expression: 42 mm<first focal length<44 mm.

[0077] The second focal length of the second lens L2 satisfies the following expression: 55 mm<second focal length<60 mm.

[0078] Here, the function of the cemented lens is mainly to focus the light beam initially and correct chromatic aberration and spherical aberration. The meniscus lens further adjusts the propagation direction and divergence of the light beam and reduces the aberration of the optical system through aspherical design.

[0079] The cemented lens can correct the chromatic aberration of the entire optical system better, and the first focal length satisfies 42mm < f1 < 44mm. Among them, 42mm is suitable for initially focusing a strongly divergent light beam to concentrate the light beam within a certain range, and 44mm ensures that the light beam is not over-focused, reserving sufficient adjustment space for the subsequent meniscus lens. The design of the first focal length can effectively guarantee the initial adjustment effect of the light beam adjustment group Q1 and lay the foundation for the high-resolution imaging of the entire optical system.

[0080] The meniscus lens can converge the intermediate image plane of the optical system near it, which is beneficial to adjusting the optical system to adapt to the eye axis lengths of different age groups on the premise of meeting the better imaging requirements. The second focal length satisfies 55mm < f2 < 60mm. Among them, 55mm is suitable for further adjusting the divergence of the short-focus light beam to make the light beam more uniform in the propagation path, and 60mm ensures that the divergence of the light beam is moderate, providing ideal input conditions for the final focusing of the focusing group. The design of the second focal length ensures that the propagation direction and divergence of the light beam when passing through the second lens L2 can match the design parameters of the light beam focusing group Q2.

[0081] In one embodiment, referring to Figure 2 , a dichroic mirror G300 is provided between the light beam adjustment group Q1 and the light beam focusing group Q2; the light beam adjustment group Q1, the dichroic mirror G300, and the light beam focusing group Q2 are coaxial; the dichroic mirror G300 forms an angle of 45° with the optical axis.

[0082] Here, the light beam adjustment group Q1, the dichroic mirror G300, and the light beam focusing group Q2 are coaxial, enabling the optical system to form a direct-through optical structure, which can make the light path of the optical system gentle. With a small number of lenses and a stable light path, many light reflection losses can be reduced, resulting in a high return light effect of the human eye G200 and making it easy to obtain a strong interference signal.

[0083] The dichroic mirror G300 is used to transmit the light beam within the first wavelength band range; the first wavelength band range is 820nm ≤ light beam wavelength ≤ 1150nm.

[0084] Here, the dichroic mirror G300 is located between the light beam adjustment group Q1 and the light beam focusing group Q2, and can selectively process the light before the adjusted light beam is transmitted to the light beam focusing group Q2.

[0085] The dichroic mirror G300 is placed at an angle of 45°, enabling it to effectively separate and reflect light within different wavelength ranges, ensuring that the light propagates or reflects in the expected direction and improving the utilization efficiency of the optical path.

[0086] The first wavelength range refers to the light beam within the main working wavelength range emitted from the scanning light source, and the wavelength range is 820nm to 1150nm. The dichroic mirror G300 allows the light beam in the first wavelength range to pass through the dichroic mirror G300 and be transmitted to the beam focusing group Q2 to achieve fundus imaging, thereby excluding light in other wavelength bands to reduce unnecessary optical interference.

[0087] In one embodiment, referring to Figure 2 The optical system also includes a pupil lens L4 and a detector G400; the pupil lens L4 is arranged below the dichroic mirror G300; and the detector G400 is arranged on a side of the pupil lens L4 close to the light source.

[0088] The dichroic mirror G300 is also used to receive the return light returned by the human eye G200, and reflect the return light within the second wavelength band to the pupil lens L4, so that the return light passes through the pupil lens L4 to reach the detector G400; the second wavelength band is 700nm≤return light wavelength≤800nm.

[0089] The detector G400 is used to generate an OCT image (fundus tomographic image) corresponding to the human eye G200 based on the returned light.

[0090] Here, the detector G400 may be a CMOS (Complementary Metal Oxide Semiconductor) sensor.

[0091] The light returning from the eye is reflected downward by the side of the dichroic mirror G300 (the side close to the third lens L3), and reaches the detector G400 through the pupil lens L4. This light path, as the pupil optical path, can realize dynamic tracking of the user's pupil information. Among them, the curvature radius of the side of the dichroic mirror G300 is smaller than the curvature radius of the side of the human eye G200.

[0092] The position of pupil lens L4 is designed on the reflection path of dichroic mirror G300 to ensure that the light returned from human eye G200 reaches detector G400 after precise focusing. Detector G400 is designed on the exit side of pupil lens L4 to directly receive the focused return light. Detector G400 provides the basis for generating OCT images by receiving light signals and converting them into electrical signals.

[0093] The return light is the signal light reflected from the human eye G200, which meets the second band interval of 700nm to 800nm. The return light of a specific band is guided to the pupil lens L4 through the reflection function to avoid interference from other bands of light. Among them, the light in the second band interval is used to generate OCT images to ensure the clarity and resolution of the image.

[0094] Figure 3A schematic diagram of surface annotation of an optical system provided by an embodiment of the present invention.

[0095] Under the premise of meeting the above conditions, refer to Figure 3 , and three specific optical system design parameters are given.

[0096] Design parameters of the first optical system:

[0097] Table 1 is an optical system parameter table corresponding to the first optical system design parameters.

[0098] Table 1

[0099]

[0100]

[0101] Among them, the object plane refers to the surface behind the galvanometer, which is used to define the starting point of light entering the optical system. The radius of curvature is used to describe the curvature of each surface. When the radius of curvature is positive, the surface protrudes outward, and when the radius of curvature is negative, the surface is concave inward. The surface spacing refers to the axial distance between two optical elements. The aspheric coefficient K is used to describe the aspheric shape of the lens. When K=0, the surface is spherical, and when K≠0, the surface is aspherical.

[0102] CT1 is the distance between S3 and S4, CT2 is the distance between S5 and S6. Since the distance between the first lens and the third lens is fixed and the position of the dichroic mirror is fixed, it can be determined that the moving distance between the second lens and the beam focusing group = the distance CT2 between S5 and S6, and CT1+CT2 is a fixed value.

[0103] TTL1 was set to 104.76 mm. Three different structures were set according to different axial lengths. See Table 2 for details.

[0104] Table 2

[0105] structure Axial length (mm) CT1(mm) CT2(mm) G1 16 2.195 33.416 G2 19 12.116 23.495 G3 23 22.625 12.986

[0106] Among them, the focal length of the G1 structure system is -10.63mm, the focal length of the G2 structure system is -12.44mm, and the focal length of the G3 structure system is -14.81mm. The F number of the G1 structure system is 7.11, the F number of the G2 structure system is 8.32, and the F number of the G3 structure system is 9.99. Figure 4-Figure 6 The point diagrams of structures G1, G2, and G3 in the design parameters of the first optical system are listed respectively. It can be seen from the figure that the radius of the Airy disk of all structures does not exceed 13um, and the designed imaging field of view is 7-8.4mm.

[0107] Reference Figure 4 , Figure 4The image plane in the image refers to the position where the light beam is finally focused after passing through the optical system, that is, the retina of the human eye. The GEO radius is the geometric spot size, which reflects the actual physical size of the light beam. The RMS radius is the root mean square radius of the spot energy distribution, which indicates the concentration of the light.

[0108] Figure 4 The point diagram of the imaging effect of different object plane tilt angles on the image plane under the G1 structure (axial length of 16mm) of the first optical system design parameters is shown. Each small figure shows the focusing distribution of light on the image plane under a certain object plane tilt angle (from 0° to 20°). The grid unit of each small figure is millimeter (mm), which indicates the actual distribution range of the light spot on the image plane. Under the G1 structure, the spot radius is less than 13um, indicating that the optical system has high imaging quality under short axial length conditions.

[0109] The colors in the figure represent the distribution of light of different wavelengths in the field of view, such as blue, green, red, etc. The size and shape of the light spot reflects the imaging quality of the optical system at the object plane angle: the smaller the light spot and the closer it is to the center, the better the imaging effect. The diffusion and offset of the light spot indicate that the imaging quality of the edge field of view is slightly reduced.

[0110] The geometric center offset of the light spot on the image plane is marked in the lower right corner of each small picture, for example, image plane: 0.000, -0.001mm. These values ​​represent the distance that the light deviates from the center of the image plane. The closer to 0, the more accurate the imaging.

[0111] The G1 structure is adapted to a short axial length of 16 mm, which is usually the eye characteristic of young infants and young children. The optical system needs to adjust the light beam propagation path so that it can still focus on the retina at a shorter axial length.

[0112] Reference Figure 4 , the performance of G1 structure on retinal imaging at different object plane angles under short axial length conditions:

[0113] In the center field of view (0° to 8°), the light spot is concentrated and the image is clear.

[0114] At the edge of the field of view (12° to 20°), the spot size begins to grow and shift, indicating a slight decrease in edge imaging quality.

[0115] The change of the object plane from 0° to 20° simulates the change of the light beam from the central field of view to the peripheral field of view. The light beam performs best in the central field of view and is slightly distorted in the peripheral field of view, but still within a reasonable range.

[0116] Based on this figure, it can be determined that the G1 structure can adapt to the short eye axis of infants and young children and meet imaging needs.

[0117] Design parameters of the second optical system:

[0118] Table 3 is an optical system parameter table corresponding to the first optical system design parameters.

[0119] Table 3

[0120]

[0121] TTL1 was set to 99.456 mm. Three different structures were set according to different axial lengths. See Table 4 for details.

[0122] Table 4

[0123] structure Axial length (mm) CT1(mm) CT2(mm) G1 16 2.2 28.187 G2 19 7.746 22.641 G3 23 10.137 20.250

[0124] Among them, the focal length of the G1 structure system is -9.37mm, the focal length of the G2 structure system is -11.75mm, and the focal length of the G3 structure system is -14.65mm. The F number of the G1 structure system is 6.30, the F number of the G2 structure system is 7.89, and the F number of the G3 structure system is 9.82. Figure 7-Figure 9 The point diagrams of structures G1, G2, and G3 in the design parameters of the second optical system are listed respectively. It can be seen from the figure that the radius of the Airy disk of all structures does not exceed 12.8um, and the designed imaging field of view is 7-9.476mm.

[0125] Design parameters of the third optical system:

[0126] Table 5 is an optical system parameter table corresponding to the third optical system design parameters.

[0127]

[0128]

[0129] TTL1 was set to 101.213 mm. Three different structures were set according to different axial lengths. See Table 6 for details.

[0130] Table 6

[0131] structure Axial length (mm) CT1(mm) CT2(mm) G1 16 2.2 26.309 G2 19 7.983 20.526 G3 23 10.869 17.640

[0132] Among them, the focal length of the G1 structure system is -9.27mm, the focal length of the G2 structure system is -11.62mm, and the focal length of the G3 structure system is -14.62mm. The F number of the G1 structure system is 6.22, the F number of the G2 structure system is 7.80, and the F number of the G3 structure system is 9.80. Figure 10-12 The point diagrams of structures G1, G2, and G3 in the design parameters of the third optical system are listed respectively. It can be seen from the figure that the radius of the Airy disk of all structures does not exceed 12.7um, and the designed imaging field of view is 7-9.408mm.

[0133] The embodiment of the present application provides an optical system of a handheld OCT device, including: a galvanometer, a beam adjustment group and a beam focusing group are arranged in sequence from the light source to the human eye; the focal length ratio between the focal length of the beam adjustment group and the focal length of the beam focusing group satisfies the following relationship: 1<focal length ratio<1.2; the galvanometer is used to scan the light emitted by the light source to the beam adjustment group to generate a beam; the beam adjustment group is used to adjust the propagation direction and divergence of the beam emitted by the galvanometer; the beam focusing group is used to focus the beam adjusted by the beam adjustment group to the human eye so that the beam is imaged at the retina of the human eye. In this way, by adapting the focal length ratio of the beam adjustment group and the beam focusing group and motor control, accurate imaging of different axial lengths (19mm-23mm) and small pupil diameters (2mm-3mm) is achieved. The optimized design of the aspheric lens effectively reduces aberrations, improves imaging resolution, and ensures high-definition imaging capabilities in both the central field of view and the edge field of view. The optical system is compactly designed, supports dynamic pupil tracking and efficient OCT imaging, and is suitable for fundus examination needs of infants and young children.

[0134] Embodiment 2:

[0135] Fig.13 A schematic diagram of a handheld OCT device provided in an embodiment of the present invention.

[0136] Reference Fig.13 The handheld OCT device includes a light source 1; and also includes the optical system 2 of the handheld OCT device mentioned above; the light source 1 is arranged on a side of the optical system 2 of the handheld OCT device away from the human eye.

[0137] Here, light source 1 is located on the side of the optical system away from the human eye, that is, light source 1 generates a light beam through a galvanometer, passes through a beam adjustment group and a beam focusing group in sequence, and finally forms an image on the retina. The setting of the position of light source 1 ensures that the light propagation path is reasonable and reduces the beam divergence loss. Light source 1 is combined with the above optical system to ensure that the light beam can be accurately adjusted and focused, and supports dynamic adjustment to adapt to different axial lengths and pupil diameters.

[0138] The light source 1 includes a scanning light source and an illumination light source; the scanning light source is infrared light, the working wavelength range of the scanning light source is 1060nm-1150nm, and the central wavelength is 1060nm; the illumination light source is visible light, and the working wavelength range of the illumination light source is 820-860nm.

[0139] The scanning light source is infrared light with an operating wavelength of 1060nm-1150nm and a central wavelength of 1060nm. It is used for deep imaging of OCT and has strong penetrating power, and can perform high-definition sectional imaging of the fundus retina.

[0140] The illumination source is visible light with an operating wavelength of 820nm-860nm, which is used to illuminate the surface of the human eye and assist in the observation and positioning of the pupil or retina.

[0141] The scanning light source and the illumination light source are responsible for different functions respectively. The scanning light source is used for OCT imaging, and the illumination light source assists in positioning, working together to complete efficient inspection.

[0142] The embodiment of the present application provides a handheld OCT device. By integrating a scanning light source and an illumination light source, the device can not only achieve high-definition fundus tomography, but also provide visible light auxiliary positioning to meet complex inspection requirements. The design of the light source away from the human eye optimizes the optical path, reduces light interference, and improves imaging efficiency and accuracy. The handheld OCT device has a compact structure and comprehensive functions, and is particularly suitable for portable ophthalmic examination applications for infants and young children.

[0143] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the system and device described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0144] In addition, in the description of the embodiments of the present application, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0145] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0146] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0147] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application, rather than to limit them. The protection scope of the present application is not limited thereto. Although the present application is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed in the present application, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. An optical system of a handheld OCT device, characterized in that: include: A galvanometer, a beam adjustment group and a beam focusing group are sequentially arranged from the light source to the human eye; the focal length ratio between the focal length of the beam adjustment group and the focal length of the beam focusing group satisfies the following relationship: 1<focal length ratio<1.2; The galvanometer is used to scan the light emitted by the light source to the beam adjustment group to generate a light beam; The beam adjustment group is used to adjust the propagation direction and divergence of the light beam emitted by the galvanometer; The beam focusing group is used to focus the beam adjusted by the beam adjusting group onto the human eye, so that the beam forms an image at the retina of the human eye.

2. The optical system of the handheld OCT device according to claim 1, characterized in that: The optical system further includes a motor; the beam adjustment group includes a second lens; the second lens is connected to the motor; the beam adjustment group and the beam focusing group share a common optical axis; the distance between the second lens and the beam focusing group is a moving distance, and the moving distance satisfies the following relationship: 8mm≤moving distance≤25mm; The motor controls the second lens to move along the optical axis based on the moving distance to adapt to the human eyes with different axial lengths; the axial length satisfies the following relationship: 19mm≤axial length≤23mm.

3. The optical system of the handheld OCT device according to claim 1, characterized in that: The beam focusing group is a third lens; the first surface and the second surface of the third lens are both aspherical surfaces; the third focal length of the third lens satisfies the following relationship: 24.4mm<third focal length<25.2mm; The distance between the third lens and the galvanometer is a first distance, and the first distance satisfies the following relationship: 95mm<first distance<115mm; the distance between the third lens and the human eye is a second distance; the distance ratio between the first distance and the second distance satisfies the following relationship: 0.17≤distance ratio≤0.

22.

4. The optical system of the handheld OCT device according to claim 1, characterized in that: The beam adjustment group includes a first lens and a second lens arranged in sequence from the galvanometer to the beam focusing group; The first lens is used to focus the light beam; The second lens is used to adjust the propagation direction and the divergence of the focused light beam.

5. The optical system of the handheld OCT device according to claim 4, characterized in that: The first lens is a cemented lens, and the second lens is a meniscus lens; a surface of the second lens close to the first lens is an aspherical surface; The first focal length of the first lens satisfies the following expression: 42 mm < first focal length < 44 mm; The second focal length of the second lens satisfies the following expression: 55 mm<second focal length<60 mm.

6. The optical system of the handheld OCT device according to claim 1, characterized in that: A dichroic mirror is arranged between the beam adjustment group and the beam focusing group; the beam adjustment group, the dichroic mirror and the beam focusing group share a common optical axis; the dichroic mirror is at 45° with the optical axis; The dichroic mirror is used to transmit the light beam within a first wavelength range; the first wavelength range is 820nm≤light beam wavelength≤1150nm.

7. The optical system of the handheld OCT device according to claim 6, characterized in that: The optical system also includes a pupil lens and a detector; The pupil lens is arranged below the dichroic mirror; the detector is arranged on a side of the pupil lens close to the light source; The dichroic mirror is further used to receive the return light returned by the human eye, and reflect the return light in the second wavelength range to the pupil lens, so that the return light passes through the pupil lens to reach the detector; The second wavelength range is 700nm≤return light wavelength≤800nm; The detector is used to generate an OCT image corresponding to the human eye based on the returned light.

8. The optical system of the handheld OCT device according to claim 1, characterized in that: The third distance between the galvanometer and the beam adjustment group is 20 mm.

9. A handheld OCT device, characterized in that: It comprises a light source; and also comprises the optical system of the handheld OCT device as described in any one of claims 1 to 8; the light source is arranged on a side of the optical system of the handheld OCT device away from the human eye.

10. The handheld OCT device according to claim 9, characterized in that: The light source includes a scanning light source and an illumination light source; the scanning light source is infrared light, the working wavelength range of the scanning light source is 1060nm-1150nm, and the central wavelength is 1060nm; the illumination light source is visible light, and the working wavelength range of the illumination light source is 820-860nm.

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