Liquid variable focus lens and anterior segment thickness measurement system
By combining a liquid lens zoom lens with a lens group design, the problem of complex and bulky lens structure in existing optical measurement methods has been solved, realizing miniaturized and high-precision anterior segment thickness measurement and expanding the multi-parameter measurement performance of ophthalmic equipment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHANGHAI SUPORE INSTR
- Filing Date
- 2025-02-27
- Publication Date
- 2026-07-31
AI Technical Summary
Existing optical measurement methods for corneal thickness measurement use lenses with complex structures and large volumes, which do not meet the requirements for miniaturization of equipment.
It uses liquid lenses for zooming, which is achieved by changing the curvature of the lens. Combined with the lens group design, it balances aberrations, ensures measurement accuracy, and is designed as an independent device for independent installation in ophthalmic equipment.
The lens features a simple structure and small size, ensuring measurement accuracy and enabling multi-parameter measurements independently of the original optometry instrument, thus improving data accuracy.
Smart Images
Figure CN224581711U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of ophthalmic imaging, and more particularly to a liquid zoom lens and anterior segment thickness measurement system. Background Technology
[0002] In existing methods for measuring corneal thickness, optical measurement is a common approach, such as ophthalmic OCT (Optical Coherence Tomography) imaging. However, this optical structure uses mechanical zoom, which is complex and bulky, and does not meet the requirements for miniaturization of equipment. Utility Model Content
[0003] This application aims to provide a lens with a simple structure, small size, and that meets the requirements for miniaturization of equipment.
[0004] To achieve the above objectives, the technical solution of this application is as follows:
[0005] A liquid zoom lens includes: a first liquid lens, a first lens group, a second liquid lens, and a second lens group arranged sequentially along the light incident direction; wherein...
[0006] The first lens group includes a first lens and a second lens arranged sequentially along the incident direction of light;
[0007] The second lens group includes a third lens and a fourth lens arranged sequentially along the direction of light incidence.
[0008] Optionally, the first lens is a positive meniscus lens, the second lens is a biconvex lens, and the first lens and the second lens are cemented together to form a cemented doublet lens.
[0009] Optionally, the distance between the first lens group and the first liquid lens is greater than the distance between the first lens group and the second liquid lens.
[0010] Optionally, the third lens is a biconcave lens, the fourth lens is an optimally shaped lens, and the third lens and the fourth lens are cemented together to form a cemented doublet lens.
[0011] Optionally, the liquid zoom lens further includes an aperture stop located between the first liquid lens and the first lens group.
[0012] Optionally, the liquid zoom lens further includes a receiving surface located on the side of the second lens group away from the second liquid lens; the receiving surface is inclined to the liquid zoom lens.
[0013] Optionally, the distance between the second lens group and the second liquid lens is less than the distance between the second lens group and the receiving surface.
[0014] An anterior segment thickness measurement system, comprising,
[0015] A lighting device that emits light;
[0016] A light path deflector is located in the light path of the light emitted by the illumination device, and reflects the light emitted by the illumination device to the eye of the person being tested.
[0017] The liquid zoom lens as described in any one of the above examples is located in the reflected light path of the light reflected from the eye under test.
[0018] Optionally, the anterior segment thickness measurement system further includes an imaging receiver located on the side of the liquid zoom lens away from the human eye being measured.
[0019] Optionally, the light emitted by the lighting device may include slit light.
[0020] The liquid zoom lens proposed in this application uses a liquid lens for zooming. Compared with mechanical zoom, it does not require a complicated zoom mechanism. During zooming, it only needs to change the curvature of the lens to complete the imaging. When applied to an anterior segment thickness measurement system, it can ensure measurement accuracy while having a simple structure and small size, meeting the requirements of miniaturization of equipment.
[0021] The anterior segment thickness measurement system proposed in this application, based on Scherm's law, ensures that the anterior segment thickness measurement is not perpendicular to the lens optical axis, allowing for clear imaging within a designed tilt angle range. This facilitates image processing for calculating lens and corneal thickness. Furthermore, as an independent device, the anterior segment thickness measurement system used in this application does not share the optical path with existing optometry instruments. Under non-interference conditions, it can be independently installed in the instrument, expanding the ophthalmic equipment's multi-parameter measurement capabilities, enabling related parameter corrections, and ensuring the accuracy of measurement data.
[0022] To make the above features and advantages of this application more apparent and understandable, specific embodiments are described below in conjunction with the accompanying drawings. Attached Figure Description
[0023] Figure 1 This is a schematic diagram of the liquid zoom lens proposed in this application.
[0024] Figure 2 Figure (a) shows a schematic diagram of the imaging of a liquid zoom lens with a focal length of f=56.3mm.
[0025] Figure 2 Figure (b) in the figure is a schematic diagram of the imaging of a liquid zoom lens with a focal length of f=18.8mm.
[0026] Figure 3 This is a dot plot of a liquid zoom lens with a focal length f of 56.3mm at different object-side field-of-view angles.
[0027] Figure 4 This is a distortion curve of a liquid zoom lens with a focal length of f = 56.3mm.
[0028] Figure 5 This is a dot plot of a liquid zoom lens with a focal length f of 18.8mm at different object-side field-of-view angles.
[0029] Figure 6 This is a distortion curve of a liquid zoom lens with a focal length of f = 18.8mm.
[0030] Figure 7 A block diagram of an anterior segment thickness measurement system provided in this application.
[0031] In the accompanying drawings, similar reference numerals refer to the same elements. Detailed Implementation
[0032] To make the objectives and technical solutions of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the described embodiments of this application without creative effort are within the scope of protection of this application.
[0033] In one embodiment of this application, please refer to Figure 1 ,like Figure 1 The diagram shown is a schematic of the liquid zoom lens proposed in this application. The liquid zoom lens includes: a first liquid lens 1, a first lens group 2, a second liquid lens 3, and a second lens group 4 arranged sequentially along the light incident direction; wherein,
[0034] The first lens group 2 includes a first lens 21 and a second lens 22 arranged sequentially along the direction of light incidence.
[0035] The second lens group 4 includes a third lens 41 and a fourth lens 42 arranged sequentially along the direction of light incidence.
[0036] As an example, the liquid zoom lens also includes a receiving surface 5, which is located on the side of the second lens group 4 away from the second liquid lens; the receiving surface 5 is inclined to the liquid zoom lens.
[0037] The liquid zoom lens proposed in this application uses a liquid lens for zooming. Compared to mechanical zoom, it eliminates the need for a complex zoom mechanism. During zooming, only the lens curvature needs to be changed to complete the imaging. When applied to anterior segment thickness measurement systems, it offers a simple structure and small size while ensuring measurement accuracy, meeting the requirements for miniaturization. Since the aberration correction capability of liquid lenses is limited, a first lens group 2 is placed between the first liquid lens 1 and the second liquid lens 3, and a second lens group 4 is placed between the second liquid lens 3 and the receiving surface 5. This balances the spherical aberration and coma of the liquid lens, improving measurement accuracy.
[0038] As an example, the first lens 21 can be a positive meniscus lens, the second lens 22 can be a biconvex lens, and the first lens 21 and the second lens 22 can be cemented together to form a cemented doublet lens.
[0039] As an example, the position of the first lens group 2 can be set according to actual needs. In this example, the distance between the first lens group 2 and the first liquid lens 1 can be greater than the distance between the first lens group 2 and the second liquid lens 3.
[0040] As an example, the third lens 4 can be a biconcave lens, the fourth lens 42 can be an optimally shaped lens, and the third lens 41 and the fourth lens 42 can be cemented together to form a cemented doublet lens.
[0041] As an example, the liquid zoom lens may also include an aperture stop 6 located between the first liquid lens 1 and the first lens group 2.
[0042] As an example, the position of the second lens group 4 can be set according to actual needs. In this example, the distance between the second lens group 4 and the second liquid lens 3 is less than the distance between the second lens group 4 and the receiving surface 5.
[0043] For example, please refer to Figure 2 , Figure 2 Figure (a) shows a schematic diagram of the imaging process using a liquid zoom lens with a focal length of f=56.3mm. Figure 2 Figure (b) shows a schematic diagram of the imaging of a liquid zoom lens with a focal length of f=18.8mm. By adjusting the degree of deformation of the first liquid lens 1 and the second liquid lens 3, the curvature of the liquid lens is controlled, thereby achieving the effect of magnification or reduction.
[0044] As an example, to facilitate optimized use, a virtual surface 7 is introduced during the design process. The virtual surface 7 is located on the side of the second lens group 4 away from the second liquid lens 3. Specifically, the virtual surface 7 is located between the second lens group 4 and the receiving surface 5.
[0045] As an example, please refer to Table 1, which provides the curvature parameters of the first liquid lens 1 and the second liquid lens 3, where f is the focal length of the liquid zoom lens and R is the radius of curvature of the center of the lens surface, both in mm. When the focal length f is 56.3 mm, the radius of curvature R of the first liquid lens 1 is 84.7 mm and the radius of curvature R of the second liquid lens 3 is 65.1 mm. At this time, both the first liquid lens 1 and the second liquid lens 3 have positive focal power. When the focal length f is 18.8 mm, the radius of curvature R of the first liquid lens 1 is 135.3 mm and the radius of curvature R of the second liquid lens 3 is -60.8 mm. At this time, both the first liquid lens 1 and the second liquid lens 3 have negative focal power.
[0046] Table 1 Curvature parameters of the first liquid lens 1 and the second liquid lens 3
[0047]
[0048] For example, please refer to Figure 3 ,like Figure 3 The image shows a dot plot of a liquid zoom lens with a focal length f of 56.3mm at different object-side field-of-view angles. Figure 3 Figure (a) in the figure is a dot plot of a liquid zoom lens with an object-side field of view of 1.3800 degrees (deg) and a focal length f of 56.3 mm. Figure 3 Figure (b) is a dot plot of a liquid zoom lens with an object-side field of view of 0.9800 degrees (deg) and a focal length f of 56.3 mm. Figure 3 Figure (c) in the figure is a dot plot of a liquid zoom lens with an object-side field of view of 0.6900 degrees (deg) and a focal length f of 56.3 mm. Figure 3 Figure (d) in the figure is a dot plot of a liquid zoom lens with an object-side field of view of 0.4140 degrees (deg) and a focal length f of 56.3 mm. Figure 3 Figure (e) shows the dot plot of a liquid zoom lens with a focal length f of 56.3 mm at an object-side field of view of 0.0000 degrees (deg). At an object-side field of view of 0.0000 degrees (deg), the image points are relatively concentrated, and the image size IMA is 0.000 mm, indicating good image quality and low aberrations near the optical axis. As the object-side field of view increases, the image points gradually spread out, and the value of the image size IMA also gradually increases. For example, at an object-side field of view of 1.3800 degrees, the IMA reaches 3.255 mm, and the distribution range of the image points becomes wider. Off-axis aberrations gradually increase, and the image quality decreases.
[0049] Please continue reading. Figure 4 ,like Figure 4The figure shows the distortion curve of the liquid zoom lens when the focal length f is 56.3mm. The distortion is less than 0.012%. The liquid zoom lens proposed in this application meets the imaging requirements when the focal length f is 56.3mm.
[0050] As another example, please refer to Figure 5 ,like Figure 5 The image shows a dot plot of a liquid zoom lens with a focal length f of 18.8mm at different object-side field-of-view angles. Figure 5 Figure (a) in the figure is a dot plot of a liquid zoom lens with an object-side field of view of 3.4400 degrees (deg) and a focal length f of 18.8 mm. Figure 3 Figure (b) is a dot plot of a liquid zoom lens with an object-side field of view of 2.4300 degrees (deg) and a focal length f of 18.8 mm. Figure 3 Figure (c) in the figure is a dot plot of a liquid zoom lens with an object-side field of view of 1.7200 degrees (deg) and a focal length f of 18.8 mm. Figure 3 Figure (d) in the figure is a dot plot of a liquid zoom lens with an object-side field of view of 1.0320 degrees (deg) and a focal length of 18.8mm. Figure 3 Figure (e) shows the dot plot of a liquid zoom lens with a focal length f of 18.8 mm at an object-side field of view of 0.0000 degrees (deg). At an object-side field of view of 0.0000 degrees (deg), the image points are relatively concentrated, and the image size IMA is 0.000 mm, indicating good image quality and low aberrations near the optical axis. As the object-side field of view increases, the image points gradually spread out, and the value of the image size IMA also gradually increases. For example, at an object-side field of view of 3.4400 degrees, the IMA reaches 2.997 mm, and the distribution range of the image points is wider. Off-axis aberrations gradually increase, and the image quality decreases.
[0051] Please continue reading. Figure 6 ,like Figure 6 The figure shows the distortion curve of the liquid zoom lens when the focal length f is 18.8mm. The distortion is less than 0.3%. The liquid zoom lens proposed in this application meets the imaging requirements when the focal length f is 18.8mm.
[0052] In another embodiment of this application, please refer to Figure 7 ,like Figure 7 The image shown is an anterior segment thickness measurement system 600 provided in this application, comprising:
[0053] Lighting device 300, lighting device 300 emits light;
[0054] The light path deflector 500 is located in the light path of the light emitted by the illumination device 300 and reflects the light emitted by the illumination device 300 to the human eye 200 to be tested.
[0055] As provided in the above embodiment, the liquid zoom lens 100 is located on the reflected light path of the light reflected by the human eye 200 under test.
[0056] As an example, the human eye under test 200 includes the anterior segment tissue, which is located on the optical path of the light reflected by the optical path deflector 500.
[0057] As an example, the anterior segment thickness measurement system 600 may also include an imaging receiver 400 located on the side of the liquid zoom lens 100 away from the human eye 200 being measured.
[0058] As an example, the light emitted by a lighting device may include slit light.
[0059] As an example, the human eye under test 200, the liquid zoom lens 100, and the imaging receiver 400 can be distributed according to Scherm's law.
[0060] The liquid zoom lens in the anterior segment thickness measurement system proposed in this application uses liquid lenses for zooming. Compared to mechanical zoom, it eliminates the need for complex zoom mechanisms and allows for fixed-focusing based on the individual's eye socket depth. During zooming, only the lens curvature needs to be changed to achieve imaging. When applied to anterior segment thickness measurement systems, it offers a simple structure and small size while ensuring measurement accuracy, meeting the requirements for miniaturization. Since liquid lenses have limited aberration correction capabilities, lens groups are placed between liquid lenses and between the liquid lenses and the receiving surface to balance spherical and coma aberrations, improving measurement accuracy. Furthermore, based on Scherm's law, the anterior segment thickness measurement is not perpendicular to the lens optical axis, ensuring clear imaging within the designed tilt angle range, facilitating image processing for lens and corneal thickness calculations. Simultaneously, the anterior segment thickness measurement system used in this application is an independent device, not sharing the optical path with existing optometry instruments. Under non-interference conditions, it can be independently installed in the instrument, expanding the multi-parameter measurement capabilities of ophthalmic equipment, performing related parameter corrections, and ensuring the accuracy of measurement data.
[0061] Although this application has been disclosed above with reference to embodiments, it is not intended to limit this application. Anyone skilled in the art may make some modifications and refinements without departing from the spirit and scope of this application. Therefore, the scope of protection of this application shall be determined by the appended claims.
Claims
1. A liquid zoom lens, characterized by, include: A first liquid lens, a first lens group, a second liquid lens, and a second lens group are arranged sequentially along the direction of light incidence; wherein, The first lens group includes a first lens and a second lens arranged sequentially along the incident direction of light; The second lens group includes a third lens and a fourth lens arranged sequentially along the direction of light incidence; The liquid zoom lens also includes an aperture stop, which is located between the first liquid lens and the first lens group; The liquid zoom lens also includes a receiving surface, which is located on the side of the second lens group away from the second liquid lens; the receiving surface is inclined to the liquid zoom lens.
2. The liquid zoom lens of claim 1, wherein, The first lens is a positive meniscus lens, the second lens is a biconvex lens, and the first lens and the second lens are cemented together to form a cemented doublet lens.
3. The liquid zoom lens of claim 1, wherein, The distance between the first lens group and the first liquid lens is greater than the distance between the first lens group and the second liquid lens.
4. The liquid zoom lens of claim 1, wherein, The third lens is a biconcave lens, the fourth lens is an optimally shaped lens, and the third lens and the fourth lens are cemented together to form a cemented doublet lens.
5. The liquid zoom lens of claim 1, wherein, The distance between the second lens group and the second liquid lens is less than the distance between the second lens group and the receiving surface.
6. An anterior segment thickness measurement system characterized by, include, A lighting device that emits light; A light path deflector is located in the light path of the light emitted by the illumination device, and reflects the light emitted by the illumination device to the eye of the person being tested. The liquid zoom lens as described in any one of claims 1 to 5, wherein the liquid zoom lens is located in the reflected light path of the light reflected from the human eye under test.
7. The anterior segment thickness measurement system of claim 6, wherein, The anterior segment thickness measurement system further includes an imaging receiver, which is located on the side of the liquid zoom lens away from the human eye being measured.
8. The anterior segment thickness measurement system of claim 6, wherein, The light emitted by the lighting device includes slit light.