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CN-121995599-A - Optical system, imaging device, and lens device

CN121995599ACN 121995599 ACN121995599 ACN 121995599ACN-121995599-A

Abstract

The invention provides an optical system, an imaging device and a lens device. The system includes, in order from an object side to an image side, a front unit having a negative refractive power, an aperture stop, and a rear unit having a positive refractive power. The system includes at least eight lenses, the rear unit includes an aspherical lens (a) having an inflection point, and when the maximum image height of the system is represented by ImgH, the optical total length of the system is represented by L, the focal length of the front unit is represented by f1, and the focal length of a first lens (G1) included in the front unit and disposed closest to the object is represented by fG1, the system satisfies a predetermined inequality.

Inventors

  • Da Ku Zhen You

Assignees

  • 佳能株式会社

Dates

Publication Date
20260508
Application Date
20251105
Priority Date
20241107

Claims (19)

  1. 1. An optical system comprising, in order from an object side to an image side: A front unit having a negative refractive power; aperture stop, and A rear unit having a positive refractive power, Wherein the optical system comprises at least eight lenses, Wherein the rear unit includes an aspherical lens A having an inflection point, and Wherein the following inequality is satisfied: 0.40 < ImgH/L, 0.52 < fG1/f1, -2.98 < f1/f < 0.00, 12.0 < νd < 40.0, Where ImgH denotes a maximum image height of the optical system, L denotes an optical total length of the optical system, f1 denotes a focal length of the front unit, fG1 denotes a focal length of a first lens G1 included in the front unit and disposed closest to an object, f denotes a focal length of the entire optical system, and vd denotes an abbe number of a material of a negative lens GN1 disposed closest to an object among negative lenses included in the rear unit.
  2. 2. An optical system according to claim 1, Wherein in the rear unit, a positive lens, other positive lenses, and a negative lens are sequentially arranged from a position closest to the object toward the image.
  3. 3. An optical system according to claim 1, Wherein the following inequality is satisfied: 0.00 < fω1/f1 < 3.00, Wherein fω1 represents an off-axis focal length of the front unit in the sagittal direction.
  4. 4. An optical system according to claim 1, Wherein the following inequality is satisfied: -6.00 < fGR/f2 < -2.00, wherein fGR denotes a focal length of a lens GR included in the rear unit and arranged closest to an image, and f2 denotes a focal length of the rear unit.
  5. 5. An optical system according to claim 1, Wherein the optical system includes a lens B made of a resin material, and Wherein at least one of the object side lens surface and the image side lens surface of the lens B is aspherical.
  6. 6. An optical system according to claim 1, Wherein the following inequality is satisfied: 0.00 < Sag/Ea < 0.25, Where Sag represents a distance in the axial direction between a plane apex of the object side lens surface of the first lens G1 and an effective diameter position, and Ea represents an effective diameter of the first lens G1.
  7. 7. An optical system according to claim 1, Wherein the following inequality is satisfied: 48.0 < ω < 70.0, wherein ω [ ° ] represents a half-angle of view corresponding to the maximum image height of the optical system.
  8. 8. An optical system according to claim 1, Wherein the following inequality is satisfied: 1.50 < nd < 1.70, where nd denotes a refractive index of a material of the negative lens GN1 for d-line.
  9. 9. An optical system according to claim 1, Wherein the following inequality is satisfied: 0.40 < ImgH/L ≤ 3.00。
  10. 10. an optical system according to claim 1, Wherein the following inequality is satisfied: 0.52 < fG1/f1 ≤ 2.00。
  11. 11. an optical system according to claim 1, Wherein the object side lens surface of the negative lens GN1 includes a portion which is located near the axis and is convex on the object side and a peripheral portion which is concave on the object side, and Wherein the image side lens surface of the negative lens GN1 includes a portion which is located near the axis and is concave on the image side and a peripheral portion which is convex on the image side.
  12. 12. An optical system according to claim 1, Wherein the object side lens surface of the lens GR included in the rear unit and closest to the image arrangement includes a portion located near the axis and protruding on the object side and a peripheral portion recessed on the object side, and Wherein the image side lens surface of the lens GR includes a portion which is located near the axis and is recessed on the image side and a peripheral portion which is raised on the image side.
  13. 13. An optical system according to claim 1, Wherein the front unit includes two lenses and the rear unit includes six lenses.
  14. 14. An optical system according to claim 1, Wherein the front unit includes three lenses and the rear unit includes six lenses.
  15. 15. An optical system according to claim 1, Wherein the front unit includes three lenses and the rear unit includes seven lenses.
  16. 16. An optical system according to claim 1, Wherein the front unit includes four lenses and the rear unit includes seven lenses.
  17. 17. An optical system comprising, in order from an object side to an image side: A front unit having a negative refractive power; aperture stop, and A rear unit having a positive refractive power, Wherein the front unit comprises at least two lenses, Wherein the rear unit includes an aspherical lens having an inflection point, and Wherein the following inequality is satisfied: 0.40 < ImgH/L, Where ImgH represents the maximum image height of the optical system, and L represents the optical total length of the optical system.
  18. 18. An image pickup apparatus comprising: the optical system according to any one of claims 1 to 17, and And an image pickup device that receives an image formed by the optical system.
  19. 19. A lens apparatus, comprising: the optical system according to any one of claims 1 to 17, and An operation unit configured to be operated by a user.

Description

Optical system, imaging device, and lens device Technical Field The disclosure in this specification relates to a system suitable for a digital still camera, a digital video camera, a monitoring camera, an on-board camera, a smart phone camera, and the like, an apparatus including the system, and a lens apparatus including the system. Background The wide-angle optical system needs to have high optical performance while having a small size. Japanese patent application laid-open No. 2023-184065 discloses a wide-angle optical system in which a front lens unit having a negative refractive power, an aperture stop, and a rear lens unit having a positive refractive power are arranged in order from the object side. Disclosure of Invention A system as one aspect of the present disclosure is a system including, in order from an object side to an image side, a front unit having a negative refractive power, an aperture stop, and a rear unit having a positive refractive power, wherein the system includes at least eight lenses, the rear unit includes an aspherical lens a having an inflection point, and satisfies the following inequality: 0.40 < ImgH/L 0.52 < fG1/f1 -2.98 < f1/f < 0.00 12.0 < νd < 40.0 Where ImgH denotes the maximum image height of the system, L denotes the total optical length of the system, f1 denotes the focal length of the front unit, fG1 denotes the focal length of the first lens G1 included in the front unit and arranged closest to the object, f denotes the focal length of the entire system, and νd denotes the abbe number of the material of the negative lens GN1 arranged closest to the object, of the negative lenses included in the rear unit. Features of the present disclosure will become apparent from the following description of embodiments with reference to the accompanying drawings. The following description of the embodiments is described by way of example. Drawings Fig. 1 is a cross-sectional view of the optical system of example 1 during infinity focusing. Fig. 2 is a longitudinal aberration diagram corresponding to example 1. Fig. 3 is a cross-sectional view of the optical system of example 2 during infinity focusing. Fig. 4 is a longitudinal aberration diagram corresponding to example 2. Fig. 5 is a cross-sectional view of the optical system of example 3 during infinity focusing. Fig. 6 is a longitudinal aberration diagram corresponding to example 3. Fig. 7 is a cross-sectional view of the optical system of example 4 during infinity focusing. Fig. 8 is a longitudinal aberration diagram corresponding to example 4. Fig. 9 is a schematic view related to the sagittal height of the first lens G1. Fig. 10 is a schematic diagram relating to the point of impingement of off-axis rays on an optical surface. Fig. 11 is a schematic diagram of an image pickup apparatus using the optical system of one of examples 1 to 4. Fig. 12 is a schematic diagram of a lens apparatus using the optical system of one of examples 1 to 4. Detailed Description Hereinafter, embodiments disclosed in the present specification will be described in detail with reference to the accompanying drawings. In the drawings, the same members are given the same reference numerals, and repetitive description thereof will be omitted. Fig. 1,3, 5, and 7 are sectional views of the optical system L0 of examples 1 to 4, respectively, during infinity focusing. The optical system L0 of each example will be used for an image pickup apparatus such as a digital still camera, a digital video camera, a monitoring camera, and an on-board camera. In each sectional view, the left side is the object side and the right side is the image side. The optical system L0 of each example includes a plurality of lens units. Note that the lens units in this specification refer to lens groups isolated from each other by the aperture stop SP. Further, each lens unit may include one lens or may include a plurality of lenses. Further, each lens unit may include an aspherical lens, a fresnel lens, a super lens (meta-lens), a diffractive optical element, and the like. In the optical system L0 of each example, li denotes an i-th (i is a natural number) lens unit counted from the object side among lens units included in the optical system L0. In addition, gk denotes a kth (k is a natural number) lens counted from the object side among lens units included in the optical system. In the optical system L0 of each example, L1 (LF) denotes a front unit as a lens unit disposed on the object side with respect to the aperture stop. In addition, L2 (LR) denotes a rear unit which is a lens unit arranged on the image side with respect to the aperture stop. In each sectional view, SP is an aperture stop. Further, FL is an optical element corresponding to an optical filter, a low-pass filter, an infrared cut filter, or the like. IP is an image plane, and when the optical system L0 of each example is used as an image pickup optical system of a digital still camera or a digital video cam