Ophthalmology OCT imaging device and OCT sample arm

Abstract

The invention discloses an ophthalmology OCT (optical coherence tomography) imaging device and an OCT sample arm, belongs to the field of medical instruments, particularly relates to the field of ophthalmology OCT medical equipment, and can be applied to scenes such as imaging measurement of various parameters of an eye axis and a fundus. The ophthalmology OCT imaging device comprises an eyepiece, a first fixed lens group, a second fixed lens group, a movable lens group and a scanning mirror, and the first fixed lens group is arranged close to the eyepiece; the second fixed lens group is arranged close to the scanning mirror; and the movable lens group, the first fixed lens group and the second fixed lens group are arranged on the same optical axis, and the movable lens group can move between the first fixed lens group and the second fixed lens group along the optical axis so as to realize switching between an eye axial length imaging measurement mode and an anterior segment imaging measurement mode.

Description

[0001] This application is a divisional application of the original application with the application date of August 10, 2022, application number 202210955482.0, and invention title "An Ophthalmic OCT Imaging Device and an OCT Sample Arm". Technical Field

[0002] The present disclosure relates to the technical field of medical devices, particularly to the field of ophthalmic OCT medical devices, and can be applied to scenarios such as imaging measurements of various parameters of the eye axis and fundus. Background Art

[0003] With the deepening of the aging degree and the continuous problem of bad eye - using habits among teenagers, refractive eye problems occur relatively commonly, and the growth trend of patients visiting ophthalmology clinics is obvious. Currently, eye imaging technology is widely used in analyzing refractive eye problems. Through eye imaging, data is extracted from the imaging, and objective analysis of ophthalmic biological parameters such as eye - axis length, anterior - segment corneal radius, and fundus is carried out to provide data support for medical diagnosis and surgery, etc.

[0004] Optical Coherence Tomography (OCT) technology is a relatively advanced imaging technology in the field of ophthalmic imaging. It has the characteristics of high resolution and non - damage to the measured tissue, providing a more accurate and convenient method for understanding and detecting eye diseases. Currently, eye imaging devices based on OCT technology have been applied in ophthalmology clinics. During the process of implementing the embodiments of the present disclosure, the inventors found through research on existing OCT imaging technology that there are mainly two ways to measure the eye axis. One is to first complete anterior - segment imaging measurement and posterior - segment imaging measurement separately, and finally convert the two measurements into eye - axis length measurement. Since the anterior - segment imaging measurement and the posterior - segment imaging measurement are carried out at different times, there is a measurement time difference. During the time - sharing measurement process, it is impossible to avoid measurement errors caused by the rotation of the eyeball and mechanical changes of the device. The other is to set multiple independent optical paths. For example, one imaging optical path corresponds to the anterior segment and another imaging optical path corresponds to the posterior segment, which can achieve simultaneous imaging of the anterior segment and the posterior segment. However, it is difficult to ensure consistent imaging quality with multiple independent optical paths. Both of the above two solutions have the problem of inaccurate eye - axis length measurement. Summary of the Invention

[0005] The present disclosure provides an ophthalmic OCT imaging device and an OCT sample arm to solve the technical problem of inaccurate measurement results caused by time - sharing eye - axis length measurement in related technologies.

[0006] In a first aspect, to solve the above - mentioned technical problem, an embodiment of the present disclosure provides an ophthalmic OCT imaging device, including: an OCT sample arm, wherein,

[0007] The OCT sample arm includes: an eyepiece, a first fixed lens group, a second fixed lens group, a movable lens group, and a scanning mirror, where,

[0008] The first fixed lens group is disposed close to the eyepiece;

[0009] The second fixed lens group is disposed close to the scanning mirror; and

[0010] The movable lens group, the first fixed lens group, and the second fixed lens group are disposed on the same optical axis, and the movable lens group can move along the optical axis between the first fixed lens group and the second fixed lens group to realize the switching between the axial length imaging measurement mode and the anterior segment imaging measurement mode.

[0011] Optionally, when the movable lens group moves along the optical axis and approaches the first fixed lens group, the ophthalmic OCT imaging device switches to the anterior segment imaging measurement mode; and / or

[0012] When the movable lens group moves along the optical axis and approaches the second fixed lens group, the ophthalmic OCT imaging device switches to the axial length imaging measurement mode.

[0013] Optionally, during the measurement mode switching process, the optical path from the eyepiece to the scanning mirror remains unchanged.

[0014] Optionally, the imaging numerical aperture NA1 of the OCT optical path in the axial length imaging measurement mode is smaller than the imaging numerical aperture NA2 of the OCT optical path in the anterior segment imaging measurement mode.

[0015] Optionally, the following condition is satisfied between the imaging numerical aperture NA1 and the imaging numerical aperture NA2:

[0016] NA2 / NA1 > 1.3; or

[0017] 2.5 > NA2 / NA1 > 1.3.

[0018] Optionally, in the axial length imaging measurement mode, the imaging light beam reaching the cornea of the eye to be measured through the OCT sample arm is a divergent light beam; and / or

[0019] In the anterior segment imaging measurement mode, the imaging light beam passing through the OCT sample arm is an approximately telecentric light beam in front of the cornea of the eye to be measured.

[0020] Optionally, in the axial length imaging measurement mode, the imaging light beam reaching in front of the cornea of the eye to be measured through the OCT sample arm converges at the equivalent conjugate position of the scanning mirror.

[0021] Optionally, the focal length f of the first fixed lens group 1, the focal length f of the movable lens group 2 , the focal length f of the second fixed lens group 3 satisfy at least one of the following conditions:

[0022] 2 < f 1 / f 2 < 6;

[0023] 0.6 < f 1 / f 3 < 1.7.

[0024] Optionally, in the axial length imaging measurement mode, the intermediate image plane conjugate to the object plane in the optical path between the scanning mirror and the eye to be measured appears at the position between the internal lenses in the second fixed lens group; and / or

[0025] In the anterior segment imaging measurement mode, no intermediate image plane appears at the position between the internal lenses in the second fixed lens group.

[0026] Optionally, the movable lens group includes at least one of the following:

[0027] at least 1 cemented lens;

[0028] at least 1 first meniscus lens, and the center of curvature of the at least 1 first meniscus lens is on the side facing the first fixed lens group;

[0029] at least 1 second meniscus lens, and the center of curvature of the at least 1 second meniscus lens is on the side facing the second fixed lens group.

[0030] Optionally, the first fixed lens group includes at least 1 third meniscus lens, and the center of curvature of the at least 1 third meniscus lens is on the side facing the movable lens group.

[0031] Optionally, the optical power of the second fixed lens group is positive, and the second fixed lens group includes at least 1 cemented lens.

[0032] Optionally, the working distance between the eyepiece and the eye to be measured in the axial length imaging measurement mode is greater than the working distance between the eyepiece and the eye to be measured in the anterior segment imaging measurement mode.

[0033] Optionally, in the axial length imaging measurement mode, the imaging field of view range of the OCT sample arm is greater than a first preset value; and / or

[0034] In the anterior segment imaging measurement mode, the imaging field of view range of the OCT sample arm is greater than a second preset value;

[0035] wherein, the second preset value is greater than the first preset value.

[0036] Optionally, the scanning angle α of the scanning mirror in the anterior segment imaging measurement mode and the scanning angle β of the scanning mirror in the axial length imaging measurement mode satisfy the condition: α / β > 1.5.

[0037] In a second aspect, the present disclosure provides an OCT sample arm for an ophthalmic OCT imaging device, wherein the OCT sample arm includes: an eyepiece, a first fixed lens group, a second fixed lens group, a movable lens group, and a scanning mirror, wherein,

[0038] The first fixed lens group is disposed close to the eyepiece;

[0039] The second fixed lens group is disposed close to the scanning mirror; and

[0040] The movable lens group, the first fixed lens group, and the second fixed lens group are disposed on the same optical axis, and the movable lens group can move along the optical axis between the first fixed lens group and the second fixed lens group to achieve the switching between the axial length imaging measurement mode and the anterior segment imaging measurement mode.

[0041] Through the technical solutions in one or more of the above embodiments of the present disclosure, the embodiments of the present disclosure have at least the following technical effects:

[0042] A movable lens group is provided in the OCT sample arm. By adjusting the position of the movable lens group in the OCT optical path, the switching between two imaging measurement modes is achieved. Since the same imaging optical path is actually used in the two measurement modes, and the components in the optical path are only different in position and there is no change in the optical path length in the OCT sample arm, and the imaging position in the OCT sample arm remains unchanged, and the image position does not need to be adjusted during mode switching, so the imaging quality of the image in the two measurement modes can be ensured to be consistent. In the axial length imaging measurement mode, the imaging numerical aperture of the OCT optical path is small, which can increase the depth of focus, so that the detection depth of the light source can meet the length measurement of the whole eye, achieving a uniform imaging effect of the whole eye, and the fundus visual field is large and convenient for fixation; in the anterior segment imaging measurement mode, by changing the position of the movable lens group, the imaging numerical aperture of the OCT optical path is increased, meeting the high-resolution imaging requirements of the anterior segment, and at the same time, a telecentric design can be realized to meet the requirements of repeated testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Schematically shows a schematic diagram of an ophthalmic OCT imaging device according to an embodiment of the present disclosure;

[0044] Figure 2 Schematically shows a schematic diagram of the structure of the OCT sample arm in the axial length imaging measurement mode according to an embodiment of the present disclosure;

[0045] Figure 3Schematically shows a schematic diagram of the OCT sample arm in the anterior segment imaging measurement mode in an embodiment of the present disclosure. Detailed implementation manners

[0046] Next, the technical solutions in the embodiments of the present disclosure will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present disclosure.

[0047] First, introduce the concepts of eye axis, anterior segment of the eye, and posterior segment of the eye. If the eye axis is described by regarding the eye as an optical instrument, the distance from the outermost layer that receives light in the eyeball, that is, from the cornea - lens - vitreous - retina, is regarded as the central axis of the physical optical system, which is the so-called "eye axis". The change of the eye axis can directly and objectively reflect problems such as myopia and hyperopia. Clinically, the visual organs include the eyeball, orbit, accessory organs of the eye, visual pathway, visual cortex, and related vascular and nerve structures of the eye, etc.

[0048] Speaking from inside the eye, the ocular tissues in front of the lens, including the lens, are called the anterior segment of the eye, and the ocular tissues behind the lens are called the posterior segment of the eye. Observing the anterior segment of the eye can also show the morphological structure of the posterior segment of the eye, and it has good application prospects in the diagnosis, follow-up observation, and treatment effect evaluation of intraocular diseases, especially retinal diseases.

[0049] The embodiment of the present disclosure provides an OCT sample arm for an ophthalmic OCT imaging device. Among them, the OCT sample arm includes: an eyepiece, a first fixed lens group, a second fixed lens group, a movable lens group, and a scanning mirror.

[0050] Among them, the first fixed lens group is arranged close to the eyepiece; the second fixed lens group is arranged close to the scanning mirror; and the movable lens group, the first fixed lens group, and the second fixed lens group are arranged on the same optical axis, and the movable lens group can move along the optical axis between the first fixed lens group and the second fixed lens group to realize the switching between the eye axis length imaging measurement mode and the anterior segment imaging measurement mode.

[0051] For a more intuitive understanding of the structure of the OCT sample arm provided in the present disclosure, the following will be described in detail in conjunction with the accompanying drawings and an ophthalmic OCT imaging device.

[0052] The ophthalmic OCT imaging device includes an OCT sample arm, and the OCT sample arm includes: an eyepiece, a first fixed lens group, a second fixed lens group, a movable lens group, and a scanning mirror. Among them, the first fixed lens group is arranged close to the eyepiece; the second fixed lens group is arranged close to the scanning mirror; and the movable lens group, the first fixed lens group, and the second fixed lens group are arranged on the same optical axis, and the movable lens group can move along the optical axis between the first fixed lens group and the second fixed lens group to realize the switching between the axial length imaging measurement mode and the anterior segment imaging measurement mode.

[0053] Reference Figure 1 As shown, it is a schematic structural diagram of an ophthalmic OCT imaging device provided by an embodiment of the present disclosure. The ophthalmic OCT imaging device includes an OCT sample arm.

[0054] The structure of the OCT sample arm refers to Figure 2 As shown. The OCT sample arm includes: an eyepiece 1, a first fixed lens group G1, a movable lens group G2, a second fixed lens group G3, and a scanning mirror 12. The scanning mirror 12 can be a rotary scanning mirror or a rotary polygon mirror.

[0055] In the embodiment of the present disclosure, the first fixed lens group G1 is arranged close to the eyepiece 1; the second fixed lens group G3 is arranged close to the scanning mirror 12. The movable lens group G2, the first fixed lens group G1, and the second fixed lens group G3 are arranged on the same optical axis, and the movable lens group G2 can move along the optical axis between the first fixed lens group G1 and the second fixed lens group G3. By changing the position of the movable lens group G2 on the optical axis, the switching between the axial length imaging measurement mode and the anterior segment imaging measurement mode of the OCT imaging device can be realized.

[0056] In the embodiment of the present disclosure, return to reference Figure 1 As shown, the ophthalmic OCT imaging device may further include: a first dichroic mirror 2, a second dichroic mirror 3, an iris camera module 4, a fixation light module 5, an OCT reference arm 6, a light source 7, a first fiber optic coupler 8, a second fiber optic coupler 9, and an imaging processing center 10.

[0057] Among them, the light source 7 can be a broadband light source that provides a source light beam. The first fiber optic coupler 8 splits the source light beam provided by the light source 7, and the split light enters the OCT reference arm 6 and the OCT sample arm respectively. The light beam entering the OCT sample arm sequentially passes through the scanning mirror 12, the second fixed lens group G3, the movable lens group G2, the first fixed lens group G1, and the first dichroic mirror 2, and reaches the eye to be measured through the eyepiece 1. The eyepiece 1 is close to the eye to be measured, receives the light beam returned by the eye to be measured, and reflects it to the first dichroic mirror 2 for splitting; the light beam split by the first dichroic mirror 2 enters the OCT module 11 and the second dichroic mirror 3 respectively. Here, the OCT module 11 includes the first fixed lens group G1, the second fixed lens group G3, the movable lens group G2, and the scanning mirror 12 in the OCT sample arm. The iris camera module 4 and the fixation light module 5 are split by the second dichroic mirror 3; the first dichroic mirror 2 is located between the eyepiece 1 and the second dichroic mirror 3. The fixation light module 5 includes an imaging optical path with a magnification relative to the fundus and a visible light illumination target pattern; the iris camera module 4 includes an imaging optical path with a reduction magnification relative to the iris and a camera.

[0058] The light beam returned by the OCT sample arm and the light beam returned by the OCT reference arm 6 are coupled to the imaging processing center 10 by the second fiber optic coupler 9 for imaging processing and data analysis. The imaging processing center 10 can be implemented by a computer or other forms of control centers, and the embodiments of the present disclosure do not make specific limitations on this.

[0059] Based on the above description of the OCT sample arm and the ophthalmic OCT imaging device, the following will refer to Figure 2 and Figure 3 to illustrate two measurement modes and mode switching of the ophthalmic OCT imaging device. Among them Figure 2 is a schematic structural diagram of the OCT sample arm in the axial length imaging measurement mode in the embodiments of the present disclosure; Figure 3 is a schematic structural diagram of the OCT sample arm in the anterior segment imaging measurement mode in the embodiments of the present disclosure.

[0060] It should be understood that in the embodiments of the present disclosure, the axial length imaging measurement mode and the anterior segment imaging measurement mode of the ophthalmic OCT imaging device are switched between the two measurement modes by moving the movable lens group.

[0061] Referring to Figure 2 shown, when the movable lens group G2 moves along the optical axis and approaches the second fixed lens group G3, the ophthalmic OCT imaging device switches to the axial length imaging measurement mode.

[0062] And / or, referring to Figure 3 shown, when the movable lens group G2 moves along the optical axis and approaches the first fixed lens group G1, the ophthalmic OCT imaging device switches to the anterior segment imaging measurement mode.

[0063] Return reference Figure 2 As shown, in the axial length imaging measurement mode, after movement, the position of the movable lens group G2 is close to the second fixed lens group G3. In this mode, the imaging numerical aperture of the OCT optical path in the figure is relatively small. It should be understood that the aforementioned OCT optical path refers to Figure 1 the optical path of the OCT module 11 corresponding to the OCT sample arm in. The OCT module 11 includes a first fixed lens group G1, a second fixed lens group G3, a movable lens group G2, and a scanning mirror 12. The smaller imaging numerical aperture can increase the depth of focus, enabling the detection depth of the light source to meet the length measurement of the entire eye and achieving a uniform imaging effect of the entire eye.

[0064] It should be noted that in the axial length imaging measurement mode, the movable lens group G2 can be imaged within a certain range close to the second fixed lens group G3. This position range can be represented by the imaging numerical aperture of the OCT optical path. For example, when the movable lens group G2 moves closer to the second fixed lens group G3, the corresponding imaging numerical aperture is NA1, and the variable range of the numerical aperture corresponding to the position range of the movable lens group G2 is 0.01 < NA1 < 0.03.

[0065] In the embodiment of the present disclosure, in the axial length imaging measurement mode, the imaging light beam reaching the cornea of the eye to be measured through the OCT sample arm is a divergent light beam. In this case, the telecentric angle of the imaging light beam is greater than 6 degrees. Further, in the embodiment of the present disclosure, in the axial length imaging measurement mode, the imaging light beam before reaching the cornea of the eye to be measured converges at the equivalent conjugate position of the scanning mirror 12. In addition, in this mode, as Figure 2 shown, an intermediate image plane C can be generated, that is, an intermediate image plane conjugate to the object plane in the optical path between the scanning mirror 12 and the eye to be measured is generated, and this intermediate image plane appears at the position between the internal lenses of the second fixed lens group G3.

[0066] Reference Figure 3 As shown, it is a schematic structural diagram of the OCT sample arm in the anterior segment imaging measurement mode. The position of the movable lens group G2 is close to the first fixed imaging lens group G1. In this case, the imaging numerical aperture of the OCT optical path is relatively large. The larger the imaging numerical aperture, the higher the image resolution. The larger imaging numerical aperture can meet the high-resolution imaging requirements of the anterior segment of the eye.

[0067] It should be noted that the imaging numerical aperture NA1 of the OCT optical path in the axial length imaging measurement mode is smaller than the imaging numerical aperture NA2 of the OCT optical path in the anterior segment imaging measurement mode. Optionally, the imaging numerical aperture NA1 and the imaging numerical aperture NA2 satisfy the following condition: NA2 / NA1 > 1.3. Or, optionally, the imaging numerical aperture NA1 and the imaging numerical aperture NA2 satisfy the following condition: 2.5 > NA2 / NA1 > 1.3.

[0068] And / or, in the embodiments of the present disclosure, in the anterior segment imaging measurement mode, the imaging beam passing through the OCT sample arm is an approximately telecentric beam in front of the cornea of the eye to be measured. It should be noted that in the anterior segment imaging measurement mode, the movable lens group G2 needs to be moved to a fixed position to meet the anterior segment imaging measurement requirements. This fixed position is the position where the telecentric angle of the approximately telecentric beam is the smallest. The position where the telecentric angle is the smallest is related to the size of the light source beam and the types and quantities of lenses in each lens group of the OCT sample arm, and the position where the telecentric angle is the smallest can be determined through system testing. Optionally, in some embodiments, the telecentric angle of the approximately telecentric beam can be less than 1 degree.

[0069] In the above different imaging measurement modes, the shapes of the imaging beams passing through the OCT sample arm in front of the cornea of the eye to be measured are different. In the axial length imaging measurement mode, the imaging beam reaching the cornea of the eye to be measured through the OCT sample arm is a diverging beam and converges at the equivalent conjugate position of the scanning mirror 12; in the anterior segment imaging measurement mode, the imaging beam passing through the OCT sample arm is an approximately telecentric beam in front of the cornea of the eye to be measured. This can be achieved by restricting the relationship between the focal lengths of the first fixed lens group, the second fixed lens group, and the movable lens group. In the embodiments of the present disclosure, the focal length f 1 of the first fixed lens group, the focal length f 2 of the movable lens group, and the focal length f 3 of the second fixed lens group may satisfy at least one of the following conditions:

[0070] 2 < f 1 / f 2 < 6;

[0071] 0.6 < f 1 / f 3 < 1.7.

[0072] Where " / " represents the division operation symbol.

[0073] In the embodiments of the present disclosure, as Figure 2 shown, in the axial length imaging measurement mode, the intermediate image plane C conjugate to the object plane in the optical path between the scanning mirror 12 and the eye to be measured appears at the position between the internal lenses in the second fixed lens group G3.

[0074] And / or, in the embodiments of the present disclosure, in the anterior segment imaging measurement mode, the intermediate image plane does not appear at the position between the internal lenses in the second fixed lens group.

[0075] In the embodiments of the present disclosure, in the axial length imaging measurement mode, the position of the movable lens group is close to the second fixed lens group; in the anterior segment imaging measurement mode, the position of the movable lens group is close to the first fixed lens group.

[0076] In addition, in the embodiments of the present disclosure, during the measurement mode switching process, the optical path from the eyepiece to the scanning mirror remains unchanged, that is, there is no change in the optical path in the OCT sample arm, the imaging position in the OCT sample arm remains unchanged, and the image position does not need to be adjusted during mode switching.

[0077] In addition, in the embodiments of the present disclosure, the working distance between the eyepiece and the eye to be measured in the axial length imaging measurement mode is greater than the working distance between the eyepiece and the eye to be measured in the anterior segment imaging measurement mode. Optionally, in one embodiment, the working distance in the axial length imaging measurement mode can be set to be at least 3 mm longer than the working distance in the anterior segment imaging measurement mode. Refer to Figure 2 and Figure 3 As shown, L2 represents the working distance in the axial length imaging measurement mode, L1 represents the working distance in the anterior segment imaging measurement mode, and L2 is 3 mm larger than L1.

[0078] In addition, in the embodiments of the present disclosure, the scanning angle α of the scanning mirror in the anterior segment imaging measurement mode and the scanning angle β of the scanning mirror in the axial length imaging measurement mode satisfy the condition: α / β > 1.5.

[0079] In addition, in the embodiments of the present disclosure, in the axial length imaging measurement mode, the imaging field of view range of the OCT sample arm is greater than a first preset value. And / or, in the embodiments of the present disclosure, in the anterior segment imaging measurement mode, the imaging field of view range of the OCT sample arm is greater than a second preset value. Wherein, the second preset value is greater than the first preset value. The first preset value and the second preset value can be set according to actual needs. Optionally, the first preset value can be set to 6 mm, and the second preset value can be set to 12 mm.

[0080] It should be understood that in the axial length imaging measurement mode, a larger imaging field of view range can meet the fundus fixation requirement during measurement.

[0081] Returning to the reference Figure 3 , the structure of each lens group in the OCT sample arm will be described. Figure 3 Only one composition of the lenses in the first fixed lens group G1, the second fixed lens group G3, and the movable lens group G2 is given as an example, which meets the above requirements for the numerical aperture of the OCT optical path imaging and does not limit the internal structure of the first fixed lens group G1, the second fixed lens group G3, and the movable lens group G2.

[0082] In one embodiment, the movable lens group includes at least one of the following:

[0083] At least 1 cemented lens;

[0084] At least 1 first meniscus lens, and the center of curvature of the at least 1 first meniscus lens is on the side facing the first fixed lens group;

[0085] At least one second meniscus lens, and the center of curvature of the at least one second meniscus lens is on the side facing the second fixed lens group.

[0086] In one embodiment, the first fixed lens group includes at least one third meniscus lens, and the center of curvature of the at least one third meniscus lens is on the side facing the movable lens group.

[0087] In one embodiment, the optical power of the second fixed lens group is positive, and the second fixed lens group includes at least one cemented lens.

[0088] Continue to refer to Figure 3 , for example, the movable lens group G2 can include a first meniscus lens m1, a second meniscus lens m2 and a cemented lens inside; the cemented lens is located between the first meniscus lens m1 and the second meniscus lens m2; the center of curvature of the first meniscus lens m1 is on the side facing the first fixed lens group G1; the center of curvature of the second meniscus lens m2 is on the side facing the second fixed lens group G3. For example, the first fixed lens group G1 can include two third meniscus lenses, namely meniscus lens p1 and meniscus lens p2, and the centers of curvature of these two meniscus lenses are both on the side facing the movable lens group G2; the second fixed lens group G3 can include one cemented lens.

[0089] It should be noted that the number of lenses included in each lens group can be adjusted according to the detection purpose, accuracy requirements, etc. For example Figure 3 in, the number of lens pieces on both sides of the two third meniscus lenses in the first fixed lens group G1, the number of the first meniscus lens m1, the second meniscus lens m2 and the cemented lens between the two in the movable lens group G2, and the number of lens pieces (which can be a cemented lens) in the second fixed lens group G3.

[0090] It can be understood that the above description of the composition of the lens group is a preferred structural composition and does not limit the composition of the lens group.

[0091] In the embodiments provided by the present disclosure, by adjusting the specific position of the movable lens group on the optical axis in the OCT sample arm, free switching between two working modes can be achieved, that is, free switching between the eye axis length imaging measurement mode and the anterior segment imaging measurement mode.

[0092] In the eye axis length imaging measurement mode, the imaging numerical aperture of the OCT optical path is small, which can increase the depth of focus, so that the detection depth of the light source can meet the length measurement of the entire eye, achieving a uniform imaging effect of the entire eye, and in this mode, the fundus field of view is large, which is convenient for fixation.

[0093] In the anterior segment imaging measurement mode, by moving the specific position of the movable lens group on the optical axis, the imaging numerical aperture of the OCT optical path can be increased to meet the high-resolution imaging requirements of the anterior segment imaging measurement mode, and at the same time, the telecentric design is realized to meet the repeated test requirements.

[0094] When switching between the two measurement modes, the optical path in the OCT sample arm does not change, and the imaging position does not need to be adjusted. Therefore, physical errors caused by instrument changes can be avoided, and the imaging quality can be improved.

[0095] Obviously, those skilled in the art can make various changes and modifications to the present disclosure without departing from the spirit and scope of the present disclosure. Thus, if these modifications and variations of the present disclosure fall within the scope of the claims of the present disclosure and their equivalent technologies, the present disclosure is also intended to include these changes and modifications.

Claims

1. An ophthalmic OCT imaging device, comprising: an eyepiece, a first fixed lens group, a second fixed lens group, a movable lens group and a scanning mirror, wherein, the first fixed lens group is disposed close to the eyepiece; the second fixed lens group is disposed close to the scanning mirror; and the movable lens group, the first fixed lens group and the second fixed lens group are coaxial, and the movable lens group is movable along the optical axis between the first fixed lens group and the second fixed lens group to switch between an axial length imaging measurement mode and an anterior segment imaging measurement mode.

2. The device according to claim 1, wherein: when the movable lens group moves along the optical axis and approaches the first fixed lens group, the ophthalmic OCT imaging device switches to the anterior segment imaging measurement mode; and / or when the movable lens group moves along the optical axis and approaches the second fixed lens group, the ophthalmic OCT imaging device switches to the axial length imaging measurement mode.

3. The device according to claim 1 or 2, wherein, during the measurement mode switching process, the optical path between the eyepiece and the scanning mirror remains unchanged.

4. The device according to claim 1 or 2, wherein, the imaging numerical aperture NA1 of the OCT optical path in the axial length imaging measurement mode is smaller than the imaging numerical aperture NA2 of the OCT optical path in the anterior segment imaging measurement mode.

5. The device according to claim 4, wherein, the imaging numerical aperture NA1 and the imaging numerical aperture NA2 satisfy the condition: NA2 / NA1 > 1.3; or 2.5 > NA2 / NA1 > 1.

3.

6. The device according to claim 1, wherein: in the axial length imaging measurement mode, the imaging light beam reaching the cornea of the eye to be measured through the OCT sample arm is a divergent light beam; and / or in the anterior segment imaging measurement mode, the imaging light beam passing through the OCT sample arm is an approximately telecentric light beam in front of the cornea of the eye to be measured.

7. The device according to claim 6, wherein, in the axial length imaging measurement mode, the imaging light beam reaching in front of the cornea of the eye to be measured through the OCT sample arm converges at the equivalent conjugate position of the scanning mirror.

8. The device according to claim 1, wherein, The focal length f of the first fixed lens group 1 、The focal length f of the movable lens group 2 、The focal length f of the second fixed lens group 3 Satisfy at least one of the following conditions: 2 < f 1 / f 2 < 6; 0.6 < f 1 / f 3 < 1.

7.

9. The device according to claim 1, wherein: in the axial length imaging measurement mode, the intermediate image plane conjugate to the object plane in the optical path between the scanning mirror and the eye to be measured appears at the position between the internal lenses of the second fixed lens group; and / or in the anterior segment imaging measurement mode, no intermediate image plane appears at the position between the internal lenses of the second fixed lens group.

10. The device according to claim 1, wherein, the movable lens group includes at least one of the following: at least 1 cemented lens; at least 1 first meniscus lens, and the center of curvature of the at least 1 first meniscus lens is on the side facing the first fixed lens group; at least 1 second meniscus lens, and the center of curvature of the at least 1 second meniscus lens is on the side facing the second fixed lens group.

11. The device according to claim 1, wherein, The first fixed lens group includes at least one third meniscus lens, and the curvature center of the at least one third meniscus lens is on the side facing the movable lens group.

12. The apparatus according to claim 1, wherein, the optical power of the second fixed lens group is positive, and the second fixed lens group includes at least one cemented lens.

13. The apparatus according to claim 1, wherein, the working distance between the eyepiece and the eye to be measured in the axial length imaging measurement mode is greater than the working distance between the eyepiece and the eye to be measured in the anterior segment imaging measurement mode.

14. The apparatus according to claim 1, wherein: in the axial length imaging measurement mode, the imaging field of view range of the OCT sample arm is greater than a first preset value; and / or in the anterior segment imaging measurement mode, the imaging field of view range of the OCT sample arm is greater than a second preset value; wherein, the second preset value is greater than the first preset value.

15. The apparatus according to claim 1, wherein, in the anterior segment imaging measurement mode, the scanning angle α of the scanning mirror and the scanning angle β of the scanning mirror in the axial length imaging measurement mode satisfy the condition: α / β > 1.

5.

16. An OCT sample arm for an ophthalmic OCT imaging apparatus, wherein, the OCT sample arm includes: an eyepiece, a first fixed lens group, a second fixed lens group, a movable lens group and a scanning mirror, wherein, the first fixed lens group is arranged close to the eyepiece; the second fixed lens group is arranged close to the scanning mirror; and the movable lens group, the first fixed lens group and the second fixed lens group are coaxially arranged, and the movable lens group can move along the optical axis between the first fixed lens group and the second fixed lens group to realize the switching between the axial length imaging measurement mode and the anterior segment imaging measurement mode.

Images