Sammer lens
By designing a SAM lens with a specific structure, separate focus in the meridional and sagittal directions is achieved, which is suitable for 3D modeling, produces obvious image effects, and maintains a small focus shift amount under temperature changes, thus solving the problem that existing technologies cannot achieve separate focus and large focus shift amount.
Patent Information
- Application Number
- CN202511251703.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-03
- Publication Date
- 2025-12-12
AI Technical Summary
Existing SAM lenses cannot achieve meridional and sagittal focusing, and the focus shift is significant in environments with temperature variations.
Design a SAM lens, comprising a first lens, a second lens, a third lens, and a fourth lens arranged sequentially from the object side to the image side along the optical axis. By setting the aperture stop and the optical power of the lenses, specific focal length and refractive index conditions are met to achieve meridional and sagittal focusing, and to maintain a small amount of focus shift under large temperature changes.
It achieves a split focus effect in the meridional and sagittal directions, making the horizontal lines clear and the vertical lines blurred in the 3D model, which is suitable for 3D model shooting. The focus shift is controlled within 0.02mm in the temperature range of -30℃ to 80℃.
Smart Images
Figure CN121115249A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of optical lenses, in particular to a Schlieren lens. BACKGROUND
[0002] The Schlieren lens is a special optical lens designed based on Schlieren law. When the extended planes of the object plane, the lens plane and the imaging plane intersect on a straight line, the focal plane can be expanded, so that objects not in the same plane can be clearly imaged at the same time. The Schlieren lens is often used in industrial detection and can detect objects with inclined or complex surfaces to ensure clear vision in the entire field of view.
[0003] Some existing Schlieren lenses do not have a Schlieren lens that can simultaneously realize meridional and sagittal focusing. SUMMARY
[0004] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application provides a Schlieren lens that can focus in the meridional and sagittal directions and also maintain a small focus shift in a larger temperature change environment.
[0005] The Schlieren lens according to the embodiments of the present application comprises a first lens, a second lens, a third lens and a fourth lens arranged in sequence along the optical axis from the object side to the image side; The second lens and the third lens are provided with an aperture stop, the first lens has a positive focal power, the second lens has a positive focal power, the third lens has a negative focal power, and the fourth lens has a positive focal power; The first lens satisfies the following conditional expression, 1≤F1 / F≤3, wherein F1 is the focal length of the first lens and F is the focal length of the Schlieren lens.
[0006] The Schlieren lens according to the embodiments of the present application has at least the following beneficial effects: it can realize meridional and sagittal focusing, so that the Schlieren lens can be applied to three-dimensional modeling, and the image is clearly represented as horizontal lines are clear and vertical lines are blurred; when vertical lines are clear, horizontal lines are blurred, the focal points are different, and it is suitable for three-dimensional modeling and shooting. It can also control the focus shift within 0.02mm in a temperature change of-30℃ to 80℃.
[0007] According to some embodiments of the present application, the first lens also satisfies the following conditional expression: Nd≤1.8, and Nd is the refractive index of the first lens at a wavelength of 587.56nm.
[0008] According to some embodiments of the present application, the second lens also satisfies the following conditional expression: 0.5≤F2 / F≤2.5, and F2 is the focal length of the second lens.
[0009] According to some embodiments of the present application, the third lens further satisfies the following conditional expression, -3≤F3 / F≤-0.1, F3 being the focal length of the third lens.
[0010] According to some embodiments of the present application, the fourth lens further satisfies the following conditional expression, 0.5≤F4 / F≤3, F4 being the focal length of the fourth lens.
[0011] According to some embodiments of the present application, the Schmidt lens further satisfies the following conditional expression, TTL / IH≤7, TTL being the distance from the front surface of the first lens to the image plane, and IH being the diagonal half image height of the rectangular detector.
[0012] According to some embodiments of the present application, the Schmidt lens satisfies the conditional expression TTL / IH=6.
[0013] According to some embodiments of the present application, the first lens satisfies the conditional expression F1 / F=2.5.
[0014] According to some embodiments of the present application, the first lens is provided with a filter towards the object side.
[0015] According to some embodiments of the present application, the fourth lens is provided with a protection glass towards the image side, the protection glass being parallel to the image plane.
[0016] Additional aspects and advantages of the present application will be given in part in the following description, become apparent from the following description, or be learned by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS
[0017] The present application will be further described below in conjunction with the drawings and embodiments, in which: Figure 1 Structure schematic diagram of the Schmidt lens of the embodiments of the present application; Figure 2 Point diagram of the Schmidt lens of the first embodiment of the present application; Figure 3 Light fan diagram of the Schmidt lens of the first embodiment of the present application; Figure 4 Distortion and field curvature diagram of the Schmidt lens of the first embodiment of the present application; Figure 5 MTF diagram of the Schmidt lens of the first embodiment of the present application; Figure 6 Defocus MTF diagram of the Schmidt lens of the first embodiment of the present application; Figure 7 Relative illumination diagram of the Schmidt lens of the first embodiment of the present application; Figure 8A point diagram of the Schmuel lens of the second embodiment of the present application; Figure 9 A light fan diagram of the Schmuel lens of the second embodiment of the present application; Figure 10 A distortion and field curvature diagram of the Schmuel lens of the second embodiment of the present application; Figure 11 An MTF diagram of the Schmuel lens of the second embodiment of the present application; Figure 12 An out-of-focus MTF diagram of the Schmuel lens of the second embodiment of the present application; Figure 13 A relative illuminance diagram of the Schmuel lens of the second embodiment of the present application.
[0018] Reference numerals: Filter 001; First lens 100, second lens 200, third lens 300, fourth lens 400. DETAILED DESCRIPTION
[0019] Embodiments of the present application are described in detail below with reference to the attached drawings, which show by way of example, embodiments in which the same or similar elements or elements having the same or similar functions are denoted by the same or similar reference numerals throughout the drawings. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present application, and are not to be understood as limiting the present application.
[0020] In the description of the present application, it should be understood that the orientation description, such as the orientation or position relationship indicated by up, down, etc. is based on the orientation or position relationship shown in the drawings, and is only for the purpose of facilitating the description of the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.
[0021] In the description of the present application, the plural refers to two or more. If there is a description of first, second, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the sequence of technical features indicated.
[0022] In the description of the present application, unless otherwise explicitly limited, the words such as arrangement, installation, connection, etc. should be broadly understood, and those skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solution.
[0023] The meridional focal split is a specific performance of the astigmatism in the meridional direction of the optical system, and the sagittal focal split is a specific performance of the astigmatism in the sagittal direction of the optical system. The Schmidt lens in the embodiment of the present application can realize the meridional and sagittal focal split, that is, by using the principle of astigmatism, when the horizontal line is clear, the vertical line is blurred, and when the vertical line is clear, the horizontal line is blurred, and the focal points of the two are different, which can be applied to the three-dimensional modeling scene.
[0024] Referring to Figure 1 The Schmidt lens in an embodiment of the present application comprises, in order from the object side to the image side along the optical axis, a first lens 100, a second lens 200, a third lens 300 and a fourth lens 400.
[0025] The aperture stop is arranged between the second lens 200 and the third lens 300, the first lens 100 has a positive focal power, the second lens 200 has a positive focal power, the third lens 300 has a negative focal power, and the fourth lens 400 has a positive focal power. The first lens 100 satisfies the following conditional expression, 1≤F1 / F≤3, wherein F1 is the focal length of the first lens 100, and F is the focal length of the Schmidt lens.
[0026] It can be understood that, for further optimization, the first lens 100 also satisfies the following conditional expression, Nd≤1.8, and Nd is the refractive index of the first lens 100 at a wavelength of 587.56 nm.
[0027] It can be understood that, for further optimization, the second lens 200 also satisfies the following conditional expression, 0.5≤F2 / F≤2.5, and F2 is the focal length of the second lens 200.
[0028] It can be understood that, for further optimization, the third lens 300 also satisfies the following conditional expression, -3≤F3 / F≤-0.1, and F3 is the focal length of the third lens 300.
[0029] It can be understood that, for further optimization, the fourth lens 400 also satisfies the following conditional expression, 0.5≤F4 / F≤3, and F4 is the focal length of the fourth lens 400.
[0030] It can be understood that the Schmidt lens also satisfies the following conditional expression, TTL / IH≤7, TTL is the distance from the front surface of the first lens to the image plane, and IH is the diagonal half image height of the rectangular detector.
[0031] Preferably, it can be understood that the Schmidt lens satisfies the conditional expression TTL / IH=6.
[0032] Preferably, it can be understood that the first lens 100 satisfies the condition formula F1 / F=2.5.
[0033] It can be understood that the first lens 100 is provided with a filter 001 towards the object side.
[0034] It can be understood that the fourth lens 400 is provided with a protective glass towards the image side, and the protective glass is parallel to the image plane.
[0035] Embodiment 1: A Schmidt lens, which is provided with a filter 001, a first lens 100, a second lens 200, an aperture stop, a third lens 300, a fourth lens 400, and a protective glass from the object side to the image side along the optical axis. The protective glass is parallel to the image plane. The included angle between the design target plane of the Schmidt lens and the optical axis is α, and α=40°. The effective focal length EFL of the Schmidt lens is 21mm, the aperture Fno is 5.4, and the diagonal half image height IH of the rectangular detector is 7.0mm. The following condition formulas are also satisfied: F1 / F=2.5; Nd=1.68; F2 / F=0.76; F3 / F=-0.3; F4 / F=0.92; TTL / IH=6. F1 is the focal length of the first lens 100, Nd is the refractive index of the first lens 100 at a wavelength of 587.56nm, F2 is the focal length of the second lens 200, F3 is the focal length of the third lens 300, F4 is the focal length of the fourth lens 400, F is the focal length of the Schmidt lens, TTL is the distance from the front surface of the first lens to the image plane, and IH is the diagonal half image height of the rectangular detector.
[0036] The remaining parameters of the Schmidt lens of embodiment 1 are shown in Table 1, and the optical structure is shown in Figure 1 .
[0037] Table 1 Remaining parameters of the Schmidt lens of embodiment 1
[0038] The Schmidt lens of this embodiment 1 can realize meridional and sagittal focusing, so that the Schmidt lens can be applied to three-dimensional modeling, and the image is obviously clear in horizontal lines and blurred in vertical lines; the vertical line is clear and the horizontal line is blurred, the focal points are different, and it is suitable for three-dimensional modeling shooting. The Schmidt lens can also control the focusing amount within 0.02mm in the temperature change of-30℃ to 80℃.
[0039] The spot diagram of the Schmidt lens of this embodiment is shown in Figure 2 . The light fan diagram of the Schmidt lens is shown in Figure 3 . The distortion and field curvature diagram of the Schmidt lens is shown in Figure 4 . The MTF diagram of the Schmidt lens is shown in Figure 5As shown. The out-of-focus MTF graph of this Sham lens is as follows. Figure 6 As shown. The relative illumination diagram of this Sham lens is as follows. Figure 7 As shown.
[0040] Example 2: A Sham lens comprises, along the optical axis from the object side to the image side, a filter 001, a first lens 100, a second lens 200, an aperture stop, a third lens 300, a fourth lens 400, and a protective glass. The protective glass is parallel to the image plane. The angle between the target plane and the optical axis of this Sham lens is α, and α = 40°. The effective focal length (EFL) of this Sham lens is 21 mm, the aperture (Fno) is 5.4, and the half-image height (IH) of the rectangular detector diagonal is 7.0 mm. It also satisfies the following condition: F1 / F=2.5; Nd=1.68; F2 / F=0.76; F3 / F=-0.3; F4 / F=0.92; TTL / IH=6. F1 is the focal length of the first lens 100, Nd is the refractive index of the first lens 100 at a wavelength of 587.56nm, F2 is the focal length of the second lens 200, F3 is the focal length of the third lens 300, F4 is the focal length of the fourth lens 400, F is the focal length of the SAM lens, TTL is the distance from the front surface of the first lens to the image plane, and IH is the half-image height of the rectangular detector diagonally.
[0041] The remaining parameters of the Sham lens in Example 2 are shown in Table 2, and the optical structure is as follows: Figure 1 As shown.
[0042] Table 2. Other parameters of the Sham lens in Example 2
[0043] The SAM lens in this embodiment 2 can achieve meridional and sagittal focusing, enabling its application in 3D modeling. The image clearly shows that horizontal lines are sharp while vertical lines are blurry, and vice versa, with different focal points for each, making it suitable for 3D modeling photography. Furthermore, this SAM lens can control the focus shift within 0.02mm across temperature variations ranging from -30℃ to 80℃.
[0044] The dot diagram of the Sham lens in this embodiment is as follows: Figure 8 As shown. The light fan diagram of this Sham lens is as follows. Figure 9 As shown. The distortion and field curvature diagram of this Sham lens are as follows. Figure 10 As shown. The MTF graph of this Sham lens is as follows. Figure 11 As shown. The out-of-focus MTF graph of this Sham lens is as follows. Figure 12 As shown. The relative illumination diagram of this Sham lens is as follows. Figure 13 As shown.
[0045] The embodiments of the present application are described in detail above with reference to the drawings, but the present application is not limited to the above-described embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the present application.
Claims
1. A Sham lens, characterized in that, include: A first lens, a second lens, a third lens, and a fourth lens are arranged sequentially from the object side to the image side along the optical axis; An aperture stop is provided between the second lens and the third lens. The first lens has positive optical power, the second lens has positive optical power, the third lens has negative optical power, and the fourth lens has positive optical power. The first lens satisfies the following condition. 1≤F1 / F≤3, Wherein, F1 is the focal length of the first lens, and F is the focal length of the Sham lens.
2. The Sham lens according to claim 1, characterized in that, The first lens also satisfies the following condition. Nd≤1.8, Nd is the refractive index of the first lens at a wavelength of 587.56 nm.
3. The Sham lens according to claim 1, characterized in that, The second lens also satisfies the following condition: 0.5≤F² / F≤2.5 F2 is the focal length of the second lens.
4. The Sham lens according to claim 1, characterized in that, The third lens also satisfies the following condition. -3≤F3 / F≤-0.1, F3 is the focal length of the third lens.
5. The Sham lens according to claim 1, characterized in that, The fourth lens also satisfies the following condition. 0.5≤F4 / F≤3 F4 is the focal length of the fourth lens.
6. The Sham lens according to any one of claims 1 to 5, characterized in that, The Sham lens also satisfies the following condition. TTL / IH≤7, TTL is the distance from the front surface of the first lens to the image plane, and IH is the half-image height of the rectangular detector diagonally.
7. The Sham lens according to claim 6, characterized in that, The Sham lens satisfies the condition TTL / IH=6.
8. The Sham lens according to claim 1, characterized in that, The first lens satisfies the condition F1 / F=2.
5.
9. The Sham lens according to claim 1, characterized in that, The first lens has a filter in the direction facing the object.
10. The Sham lens according to claim 1, characterized in that, The fourth lens is provided with protective glass in the direction facing the image side, and the protective glass is parallel to the image plane.