Full-frame telecentric lens and optical system thereof
By designing the optical system of a full-frame telecentric lens, the problems of magnification variation and distortion in existing lenses during machine vision inspection have been solved, achieving high-precision and wide-field-of-view inspection results, which are applicable to fields such as semiconductors, LEDs, and FPD displays.
Patent Information
- Application Number
- CN202521013305.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-21
- Publication Date
- 2026-05-05
- Estimated Expiration
- 2035-05-21
AI Technical Summary
Existing industrial lenses have problems in machine vision inspection, such as magnification changing with working distance, parallax, and large distortion, making it difficult to meet the requirements of high-precision inspection, especially in fields such as semiconductors, LEDs, and FPD displays where there is a need for inspection with a large field of view and high resolution.
Design an optical system for a full-frame telecentric lens, comprising front and rear lenses with positive optical power arranged sequentially from the object side to the image side, combined with a beam splitter and an aperture stop. The lens assembly uses cemented lenses and a specific focal length relationship to satisfy the condition NA×WD<15, thereby achieving a telecentric effect.
It offers lenses with magnification of 1x or more, supports full-frame large-area cameras, and meets the high-precision, wide-field-of-view inspection needs of fields such as semiconductors, LEDs, and FPD displays, with optical distortion of less than 0.02%.
Smart Images
Figure CN224203506U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of machine vision lens technology, and in particular to a full-frame telecentric lens and its optical system. Background Technology
[0002] In machine vision inspection systems, ordinary industrial lenses suffer from problems such as magnification changing with working distance, parallax, and large distortion, making it difficult to meet high-precision inspection requirements. Telecentric lenses, on the other hand, can improve or even eliminate these problems. Within a certain object distance range, the magnification of the image does not change with the object distance. Its principle advantage makes it very suitable for the field of precision vision inspection.
[0003] With the continuous development of the machine vision industry and the continuous improvement of camera sensor resolution, high-precision inspection fields such as semiconductors, LEDs (Light Emitting Diodes), FPDs (Flat Panel Displays), and general semiconductors require high resolution and a larger field of view. Currently, most high-resolution telecentric lenses with magnification of more than 1x on the market have a target surface of less than 1.1 inches, resulting in a small field of view. This requires multiple scans of large objects to be inspected, which affects inspection efficiency.
[0004] The above information is provided as background information only to aid in understanding this disclosure and does not constitute an assertion or admission that any of the above content can be used as prior art relative to this disclosure. Utility Model Content
[0005] The purpose of this invention is to provide a full-frame telecentric lens and its optical system to solve or at least partially solve the technical problems existing in the prior art.
[0006] To achieve this objective, the present invention adopts the following technical solution:
[0007] In a first aspect, this utility model provides an optical system for a full-frame telecentric lens, comprising a front group S1 with positive optical power, a beam splitter P, an aperture T, and a rear group S2 with positive optical power arranged sequentially from the object side to the image side; the front group S1 and the rear group S2 are each composed of a plurality of spherical lenses.
[0008] The front group S1 includes a first lens G1 with positive optical power, a second lens G2 with positive optical power, a third lens G3 with negative optical power, a fourth lens G4 with positive optical power, a fifth lens G5 with negative optical power, and a sixth lens G6 with positive optical power.
[0009] The rear group S2 includes a seventh lens G7 with negative optical power, an eighth lens G8 with negative optical power, a ninth lens G9 with positive optical power, and a tenth lens G10 with negative optical power.
[0010] The working distance WD of the optical system and the numerical aperture NA satisfy the following relationship: NA×WD<15.
[0011] Optionally, the combined focal length of the front group S1 is f S1 The combined focal length of the rear group S2 is f. S2 The f S1 f S2 The following relationship is satisfied: 0.25 < |f S1 / f S2 |<0.65.
[0012] Optionally, the second lens G2 and the third lens G3 form a cemented lens U1, and the fourth lens G4 and the fifth lens G5 form a cemented lens U2.
[0013] The focal length of the first lens G1 is f1, and f1 and f S1 The relation 1.4 < |f1 / f is satisfied. S1 |<2.0; The first lens G1 is made of high-refractive-index glass;
[0014] The focal length of the cemented lens U1 is f U1 The f U1 With the f S1 Satisfy the relation: |f S1 / f U1 |<0.5;
[0015] The focal length of the cemented lens U2 is f U2 The f U2 With the f S1 Satisfy the relation: |f S1 / f U2 |<0.25;
[0016] The focal length of the sixth lens G6 is f6, and f6 is the same as f S1 The following relationship must be satisfied: 0.8 < |f6 / f S1 |<1.3.
[0017] Optionally, the sixth lens G6 is made of crown glass.
[0018] Optionally, the eighth lens G8 and the ninth lens G9 form a cemented lens U3;
[0019] The focal length of the seventh lens G7 is f7, and f7 is the same as f... S2 The relation is satisfied: 0.15 < |f7 / f S2 |<0.25;
[0020] The focal length of the cemented lens U3 is f U3 f U3 with f S2 Satisfy the relation: |f S2 / f U3 |<1.6;
[0021] The focal length of the tenth lens G10 is f 10 The f 10 With the f S2 The following relationship is satisfied: 0.35 < |f 10 / f S2 |<0.85.
[0022] Optionally, the first lens G1, the second lens G2, and the fourth lens G4 are all biconvex lenses, the third lens G3 is a biconcave lens, and the tenth lens G10 is a plano-convex lens or a meniscus lens.
[0023] Optionally, the half-image height y' of the optical system is less than 23 mm.
[0024] Optionally, the optical axes of all spherical lenses coincide.
[0025] Secondly, this utility model provides a full-frame telecentric lens, whose optical system adopts the optical system of a full-frame telecentric lens as described above.
[0026] Compared with the prior art, the present invention has the following beneficial effects:
[0027] The telecentric lens optical system provided by this utility model has a magnification of more than 1x and supports full-frame large target area cameras, which can meet the high precision and wide field of view requirements of semiconductor, LED, FPD display and general semiconductor detection fields.
[0028] This invention has other features and advantages that will be apparent from or will be set forth in detail in the accompanying drawings and the following detailed description, which together serve to explain the particular principles of this invention. Attached Figure Description
[0029] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0030] Figure 1 This is a schematic diagram of the optical path structure of an optical system for a full-frame telecentric lens provided in an embodiment of this utility model.
[0031] Figure 2 This is an MTF curve diagram of an optical system for a high-resolution, low-distortion, dual telecentric lens provided in an embodiment of this utility model.
[0032] Figure 3 This is an optical distortion curve diagram of an optical system for a high-resolution, low-distortion, dual telecentric lens provided in an embodiment of this utility model.
[0033] Figure 4 This is a schematic diagram of the optical path structure of another full-frame telecentric lens optical system provided in this embodiment of the present invention.
[0034] Figure 5 This is an MTF curve diagram of an optical system for a high-resolution, low-distortion, dual telecentric lens provided in another embodiment of this utility model.
[0035] Figure 6 This is an optical distortion curve diagram of another high-resolution, low-distortion, dual telecentric lens optical system provided in this embodiment of the present invention. Detailed Implementation
[0036] To illustrate the possible application scenarios, technical principles, implementable specific solutions, and achievable objectives and effects of this application in detail, the following description, in conjunction with the listed specific embodiments and accompanying drawings, provides a detailed explanation. The embodiments described herein are merely illustrative of the technical solutions of this application and are therefore intended to limit the scope of protection of this application.
[0037] In this document, the term "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The term "embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment, nor does it specifically limit its independence or connection with other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the technical features mentioned in each embodiment can be combined in any way to form corresponding implementable technical solutions.
[0038] Unless otherwise defined, the technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the use of related terms herein is merely for the purpose of describing particular embodiments and is not intended to limit this application.
[0039] In the description of this application, the term "and / or" is used to describe the logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and A and B exist simultaneously. Additionally, the character " / " in this document generally indicates that the preceding and following objects have an "or" logical relationship.
[0040] In this application, terms such as “first” and “second” are used only to distinguish one entity or operation from another, and do not necessarily require or imply any actual quantity, hierarchy or order relationship between these entities or operations.
[0041] Unless otherwise specified, the use of terms such as “comprising,” “including,” “having,” or other similar expressions in this application is intended to cover non-exclusive inclusion, which does not exclude the presence of additional elements in a process, method, or product that includes the stated elements, such that a process, method, or product that includes a list of elements may include not only those defined elements but also other elements not expressly listed, or elements inherent to such a process, method, or product.
[0042] Similar to the understanding in the Examination Guidelines, in this application, expressions such as "greater than," "less than," and "exceeding" are understood to exclude the stated number; expressions such as "above," "below," and "within" are understood to include the stated number. Furthermore, in the description of the embodiments in this application, "multiple" means two or more (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups" and "multiple times," unless otherwise explicitly specified.
[0043] In the description of the embodiments of this application, the space-related expressions used, such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "vertical," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," indicate the orientation or positional relationship based on the orientation or positional relationship shown in the specific embodiments or drawings. They are only for the purpose of describing the specific embodiments of this application or for the reader's understanding, and do not indicate or imply that the device or component referred to must have a specific position, a specific orientation, or be constructed or operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.
[0044] Unless otherwise expressly specified or limited, the terms "installation," "connection," "linking," "fixing," and "setting," as used in the description of the embodiments of this application, should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two components or the interaction between two components. For those skilled in the art to which this application pertains, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.
[0045] Example 1:
[0046] Please see Figure 1 , Figure 1 This is a schematic diagram of the optical system of a full-frame telecentric lens provided in an embodiment of this utility model.
[0047] like Figure 1 As shown, the optical system includes:
[0048] It includes a front group S1 with positive optical power, a beam splitter P, an aperture T, and a rear group S2 with positive optical power, arranged sequentially from the object side to the image side; the front group S1 and the rear group S2 are each composed of several spherical lenses;
[0049] The front group S1 includes a first lens G1 with positive optical power, a second lens G2 with positive optical power, a third lens G3 with negative optical power, a fourth lens G4 with positive optical power, a fifth lens G5 with negative optical power, and a sixth lens G6 with positive optical power.
[0050] The rear group S2 includes a seventh lens G7 with negative optical power, an eighth lens G8 with negative optical power, a ninth lens G9 with positive optical power, and a tenth lens G10 with negative optical power.
[0051] The working distance WD of the optical system and the numerical aperture NA satisfy the following relationship: NA×WD<15.
[0052] In this embodiment, the aperture T is positioned in front of the seventh lens G7 to control the optical system to form a telecentric structure. The beam splitter P is positioned between the sixth lens G6 and the aperture T, and can guide the coaxial illumination source or other imaging system through the beam splitter P.
[0053] Specifically, the combined focal length of the front group S1 is f S1 The combined focal length of the rear group S2 is f. S2 The f S1 f S2 The following relationship is satisfied: 0.25 < |f S1 / fS2 |<0.65. In this embodiment, the combined focal length f of the front group S1 is... S1 And the combined focal length f of the rear group S2 S2 All have positive optical power.
[0054] Specifically, the second lens G2 and the third lens G3 form a cemented lens U1, and the fourth lens G4 and the fifth lens G5 form a cemented lens U2.
[0055] The focal length of the first lens G1 is f1, and f1 and f S1 The relation 1.4 < |f1 / f is satisfied. S1 |<2.0;In this embodiment, the first lens G1 is made of high refractive index glass. Using high refractive index material can reduce the curvature of the lens, thereby reducing advanced aberrations and reducing tolerance sensitivity;
[0056] The focal length of the cemented lens U1 is f U1 The f U1 With the f S1 Satisfy the relation: |f S1 / f U1 |<0.5; In this embodiment, the second lens G2 and the fourth lens G4 are both made of low-dispersion glass to correct system chromatic aberration, improve imaging quality, and also help reduce spherical aberration and astigmatism caused by the increase in the system's field of view.
[0057] The focal length of the cemented lens U2 is f U2 The f U2 With the f S1 Satisfy the relation: |f S1 / f U2 |<0.25;
[0058] The focal length of the sixth lens G6 is f6, and f6 is the same as f S1 The following relationship must be satisfied: 0.8 < |f6 / f S1 |<1.3. Specifically, the sixth lens, G6, is made of crown glass, which has a low refractive index and low dispersion.
[0059] Specifically, the eighth lens G8 and the ninth lens G9 form a cemented lens U3;
[0060] The focal length of the seventh lens G7 is f7, and f7 is the same as f... S2 The relation is satisfied: 0.15 < |f7 / f S2 |<0.25; Since the front group S1 has positive optical power and is separated from the seventh lens G7 by a certain distance, the separate positive and negative lens combination can correct the field curvature of the system and improve imaging consistency.
[0061] The focal length of the cemented lens U3 is f U3 fU3 with f S2 Satisfy the relation: |f S2 / f U3 |<1.6; Cemented lens U3 can compensate for the chromatic aberration of the front group S1 and also help correct field curvature;
[0062] The focal length of the tenth lens G10 is f 10 The f 10 With the f S2 The following relationship is satisfied: 0.35 < |f 10 / f S2 |<0.85. The tenth lens G10 can reduce the angle at which the principal ray enters the image plane and improve relative illumination. The first lens faces away from the aperture stop T, which helps to balance coma and distortion.
[0063] More specifically, in this embodiment, the first lens G1, the second lens G2 and the fourth lens G4 are all biconvex lenses, the third lens G3 is a biconcave lens, and the tenth lens G10 is a plano-convex lens or a meniscus lens.
[0064] As a preferred implementation, the half-image height of the optical system preferably satisfies the following relationship: y'<23mm.
[0065] In this embodiment, the optical axes of all spherical lenses coincide; the first lens G1 to the tenth lens G10 are all spherical lenses, which have good manufacturability.
[0066] For ease of understanding, as an example and an optional implementation, the relevant data of the optical system are shown in Table 1:
[0067] Table 1
[0068] surface Radius (mm) Thickness (mm) Refractive index Abbe number G1 front surface 245.73 15.0 1.90 - G1 rear surface -291.55 60.3 G2 front surface 53.89 12.0 1.50 80 G2 and G3 adhesive surfaces -249.22 3.3 1.75 - G3 rear surface 52.17 1.6 G4 front surface 90.78 9.3 1.50 80 G4 and G5 adhesive surfaces -78.18 3.0 1.75 - G5 rear surface -1640.39 0.1 G6 front surface 46.13 9.7 1.65 50 G6 rear surface 497.60 2.3 prism ∞ 32.0 1.52 64.2 ∞ 3.0 Aperture ∞ 24.8 G7 front surface -22.44 5.2 1.65 - G7 rear surface -492.62 1.4 G8 front surface -48.34 11.3 1.75 - G8 and G9 adhesive surfaces -738.91 15.0 1.90 - G9 rear surface -46.57 0.1 G10 front surface 96.48 11.2 1.92 - G11 rear surface 1511.84 62.9 Image ∞
[0069] It should be noted that in Table 1, "front surface" corresponds to... Figure 1 The left surface of the lens or lens group corresponds to the middle surface, while the rear surface corresponds to the left surface. Figure 1 The right side surface of the corresponding lens or lens group; or it can be understood as: the object surface in Figure 1 On the left, the image plane (or image surface) is... Figure 1 On the right side, the surface closer to the object is called the "front surface", and the surface closer to the image is called the "back surface".
[0070] In this example, the combined focal length of the front group S1 is f. S1 =88mm; the combined focal length of the rear group S2 is f S2 =196mm; the focal length of the first lens G1 is f1 = 148mm; the focal length of the cemented lens group U1 is f U1 = -207mm; Focal length f of cemented lens group U2U2 =356mm; the focal length of the 6th lens G6 is f6 = 77mm; the focal length of the 7th lens G7 is f7 = -36mm; the focal length of the cemented lens group U3 is f U3 =125mm, the focal length of the tenth lens G10 is f 10 =110mm.
[0071] Substituting the above values into the respective relations, we obtain:
[0072] |f S1 / f S2 |=0.449,|f1 / f S1 |=1.682,|f S1 / f U1 |=0.425,|f S1 / f U2 |=0.247,|f6 / f S1 |=0.875,|f7 / f S2 |=0.184,|f S2 / f U3 |=1.568,|f 10 / f S2 |=0.585.
[0073] Therefore, the relevant relational expression in this embodiment is satisfied, namely:
[0074] 0.25<|f S1 / f S2 |<0.65, 1.4<|f1 / f S1 |<2.0,|f S1 / f U1 |<0.5,|f S1 / f U2 |<0.25, 0.8<|f6 / f S1 |<1.3, 0.15<|f7 / f S2 |<0.25,|f S2 / f U3 |<1.6, 0.35<|f 10 / f S2 |<0.85.
[0075] The optical parameters of the optical system in this example are shown in Table 2 below:
[0076] Table 2
[0077] Working distance WD 145mm Numerical Aperture (NA) 0.077 Object-image distance 428mm Magnification 1x Half-image height y' 22mm Telecentricity <0.1° distortion 0.02％
[0078] Please continue to refer to this. Figure 2 and Figure 3 , Figure 2This is an MTF curve diagram of an optical system for a high-resolution, low-distortion, dual telecentric lens provided in an embodiment of this utility model. Figure 3 This is an optical distortion curve diagram of an optical system for a high-resolution, low-distortion dual telecentric lens provided in this embodiment of the present invention;
[0079] According to experimental verification, such as Figure 2 As shown, MTF30 is 145 lp / mm; Figure 3 As shown, the maximum optical distortion of this optical system is less than 0.02% across the entire field of view.
[0080] This embodiment, through the structural design of the optical system described above, achieves a magnification of over 1x and supports full-frame large-area cameras, thus meeting the high-precision and wide-field-of-view requirements of detection fields such as semiconductors, LEDs, FPD displays, and general semiconductors.
[0081] Example 2:
[0082] like Figure 4 As shown, Figure 4 This is a schematic diagram of the optical path structure of another full-frame telecentric lens optical system provided in this embodiment of the present invention;
[0083] The optical system includes:
[0084] It includes a front group S1 with positive optical power, a beam splitter P, an aperture T, and a rear group S2 with positive optical power, arranged sequentially from the object side to the image side; the front group S1 and the rear group S2 are each composed of several spherical lenses;
[0085] The front group S1 includes a first lens G1 with positive optical power, a second lens G2 with positive optical power, a third lens G3 with negative optical power, a fourth lens G4 with positive optical power, a fifth lens G5 with negative optical power, and a sixth lens G6 with positive optical power.
[0086] The rear group S2 includes a seventh lens G7 with negative optical power, an eighth lens G8 with negative optical power, a ninth lens G9 with positive optical power, and a tenth lens G10 with negative optical power.
[0087] The working distance WD of the optical system and the numerical aperture NA satisfy the following relationship: NA×WD<15.
[0088] In this embodiment, the aperture T is positioned in front of the seventh lens G7 to control the optical system to form a telecentric structure. The beam splitter P is positioned between the sixth lens G6 and the aperture T, and can guide the coaxial illumination source or other imaging system through the beam splitter P.
[0089] Specifically, the combined focal length of the front group S1 is f S1 The combined focal length of the rear group S2 is f.S2 The f S1 f S2 The following relationship is satisfied: 0.25 < |f S1 / f S2 |<0.65. In this embodiment, the combined focal length f of the front group S1 is... S1 And the combined focal length f of the rear group S2 S2 All have positive optical power.
[0090] Specifically, the second lens G2 and the third lens G3 form a cemented lens U1, and the fourth lens G4 and the fifth lens G5 form a cemented lens U2.
[0091] The focal length of the first lens G1 is f1, and f1 and f S1 The relation 1.4 < |f1 / f is satisfied. S1 |<2.0;In this embodiment, the first lens G1 is made of high refractive index glass. Using high refractive index material can reduce the curvature of the lens, thereby reducing advanced aberrations and reducing tolerance sensitivity;
[0092] The focal length of the cemented lens U1 is f U1 The f U1 With the f S1 Satisfy the relation: |f S1 / f U1 |<0.5; In this embodiment, the second lens G2 and the fourth lens G4 are both made of low-dispersion glass to correct system chromatic aberration, improve imaging quality, and also help reduce spherical aberration and astigmatism caused by the increase in the system's field of view.
[0093] The focal length of the cemented lens U2 is f U2 The f U2 With the f S1 Satisfy the relation: |f S1 / f U2 |<0.25;
[0094] The focal length of the sixth lens G6 is f6, and f6 is the same as f S1 The following relationship must be satisfied: 0.8 < |f6 / f S1 |<1.3. Specifically, the sixth lens, G6, is made of crown glass, which has a low refractive index and low dispersion.
[0095] Specifically, the eighth lens G8 and the ninth lens G9 form a cemented lens U3;
[0096] The focal length of the seventh lens G7 is f7, and f7 is the same as f... S2 The relation is satisfied: 0.15 < |f7 / f S2|<0.25; Since the front group S1 has positive optical power and is separated from the seventh lens G7 by a certain distance, the separate positive and negative lens combination can correct the field curvature of the system and improve imaging consistency.
[0097] The focal length of the cemented lens U3 is f U3 f U3 with f S2 Satisfy the relation: |f S2 / f U3 |<1.6; Cemented lens U3 can compensate for the chromatic aberration of the front group S1 and also help correct field curvature;
[0098] The focal length of the tenth lens G10 is f 10 The f 10 With the f S2 The following relationship is satisfied: 0.35 < |f 10 / f S2 |<0.85. The tenth lens G10 can reduce the angle at which the principal ray enters the image plane and improve relative illumination. The first lens faces away from the aperture stop T, which helps to balance coma and distortion.
[0099] More specifically, in this embodiment, the first lens G1, the second lens G2 and the fourth lens G4 are all biconvex lenses, the third lens G3 is a biconcave lens, and the tenth lens G10 is a plano-convex lens or a meniscus lens.
[0100] As a preferred implementation, the half-image height of the optical system preferably satisfies the following relationship: y'<23mm.
[0101] In this embodiment, the optical axes of all spherical lenses coincide; the first lens G1 to the tenth lens G10 are all spherical lenses, which have good manufacturability.
[0102] For ease of understanding, as an example and an optional implementation, the relevant data of the optical system are shown in Table 3:
[0103] Table 3
[0104]
[0105]
[0106] It should be noted that in Table 3, "front surface" corresponds to... Figure 4 The left surface of the lens or lens group corresponds to the middle surface, while the rear surface corresponds to the left surface. Figure 4 The right side surface of the corresponding lens or lens group; or it can be understood as: the object surface in Figure 4 On the left, the image plane (or image surface) is... Figure 1 On the right side, the surface closer to the object is called the "front surface", and the surface closer to the image is called the "back surface".
[0107] In this example, the combined focal length of the front group S1 is f. S1 =72mm; the combined focal length of the rear group S2 is f S2 =210mm; the focal length of the first lens G1 is f1 = 115mm; the focal length of the cemented lens group U1 is f U1 = -201mm; Focal length f of cemented lens group U2 U2 =330mm; the focal length of the 6th lens G6 is f6 = 86mm; the focal length of the 7th lens G7 is f7 = -37mm; the focal length of the cemented lens group U3 is f U3 =135mm, the focal length of the tenth lens G10 is f 10 =131mm.
[0108] The above arrays satisfy the relevant relational formula of this embodiment, namely:
[0109] 0.25<|f S1 / f S2 |<0.65, 1.4<|f1 / f S1 |<2.0,|f S1 / f U1 |<0.5,|f S1 / f U2 |<0.25, 0.8<|f6 / f S1 |<1.3, 0.15<|f7 / f S2 |<0.25,|f S2 / f U3 |<1.6, 0.35<|f 10 / f S2 |<0.85.
[0110] The optical parameters of the optical system in this example are shown in Table 4 below:
[0111] Table 4
[0112]
[0113]
[0114] Please continue to refer to this. Figure 5 and Figure 6 , Figure 5 This is an MTF curve diagram of an optical system for a high-resolution, low-distortion, dual telecentric lens provided in another embodiment of this utility model. Figure 6 This is an optical distortion curve diagram of another high-resolution, low-distortion dual telecentric lens optical system provided in this embodiment of the present invention.
[0115] According to experimental verification, such as Figure 5As shown, MTF30 is 145 lp / mm; Figure 6 As shown, the maximum optical distortion of this optical system is less than 0.02% across the entire field of view.
[0116] Compared to Example 1, the optical system in Example 2 has a magnification of 1.5 times and a larger numerical aperture, enabling higher precision detection. This shows that the optical system has the potential to achieve higher magnification.
[0117] Example 3:
[0118] This embodiment provides a full-frame telecentric lens, whose optical system adopts the optical system of a full-frame telecentric lens as described in Embodiment 1 or Embodiment 2;
[0119] Since the optical system has been described in detail above, it will not be repeated in this embodiment.
[0120] The above-described embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.
Claims
1. An optical system for a full-frame telecentric lens, characterized in that, It includes a front group S1 with positive optical power, a beam splitter P, an aperture T, and a rear group S2 with positive optical power, arranged sequentially from the object side to the image side; the front group S1 and the rear group S2 are each composed of several spherical lenses; The front group S1 includes a first lens G1 with positive optical power, a second lens G2 with positive optical power, a third lens G3 with negative optical power, a fourth lens G4 with positive optical power, a fifth lens G5 with negative optical power, and a sixth lens G6 with positive optical power. The rear group S2 includes a seventh lens G7 with negative optical power, an eighth lens G8 with negative optical power, a ninth lens G9 with positive optical power, and a tenth lens G10 with negative optical power. The working distance WD of the optical system and the numerical aperture NA satisfy the following relationship: NA×WD<15.
2. The optical system of a full-frame telecentric lens according to claim 1, characterized in that, The combined focal length of the front group S1 is f S1 The combined focal length of the rear group S2 is f. S2 The f S1 f S2 The following relationship is satisfied: 0.25 < |f S1 / f S2 |<0.
65.
3. The optical system of a full-frame telecentric lens according to claim 2, characterized in that, The second lens G2 and the third lens G3 form a cemented lens U1, and the fourth lens G4 and the fifth lens G5 form a cemented lens U2. The focal length of the first lens G1 is f1, and f1 and f S1 The relation 1.4 < |f1 / f is satisfied. S1 |<2.0; The focal length of the cemented lens U1 is f U1 The f U1 With the f S1 Satisfy the relation: |f S1 / f U1 |<0.5; The focal length of the cemented lens U2 is f U2 The f U2 With the f S1 Satisfy the relation: |f S1 / f U2 |<0.25; The focal length of the sixth lens G6 is f6, and f6 is the same as f S1 The following relationship must be satisfied: 0.8 < |f6 / f S1 |<1.
3.
4. The optical system of a full-frame telecentric lens according to claim 3, characterized in that, The sixth lens, G6, is made of crown glass.
5. The optical system of a full-frame telecentric lens according to claim 3, characterized in that, The eighth lens G8 and the ninth lens G9 together form a cemented lens U3; The focal length of the seventh lens G7 is f7, and f7 is the same as f... S2 The relation is satisfied: 0.15 < |f7 / f S2 |<0.25; The focal length of the cemented lens U3 is f U3 f U3 with f S2 Satisfy the relation: |f S2 / f U3 |<1.6; The focal length of the tenth lens G10 is f 10 The f 10 With the f S2 The following relationship is satisfied: 0.35 < |f 10 / f S2 |<0.
85.
6. The optical system of a full-frame telecentric lens according to claim 5, characterized in that, The first lens G1, the second lens G2, and the fourth lens G4 are all biconvex lenses; the third lens G3 is a biconcave lens; and the tenth lens G10 is a plano-convex lens or a meniscus lens.
7. The optical system of a full-frame telecentric lens according to claim 1, characterized in that, The half-image height y' of the optical system is less than 23mm.
8. The optical system of a full-frame telecentric lens according to claim 1, characterized in that, The optical axes of all spherical lenses coincide.
9. A full-frame telecentric lens, characterized in that, Its optical system employs the optical system of a full-frame telecentric lens as described in any one of claims 1-8.