OPTICAL SYSTEM, AND ACCESSORY APPARATUS AND IMAGING APPARATUS INCLUDING THE SAME

• US 20200132987A1
• Filed: 10/28/2019
• Published: 04/30/2020
• Est. Priority Date: 10/30/2018
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Nakamura, Tsubasa
• Granted Patent: US 11,428,927 B2
• Time in Patent Office: Days
• CPC Class Codes: G02B 27/0018 with means for preventing ghost images anti-reflection coatings G02B1/11
• CPC Class Codes: G03B 11/00 Filters or other obturators specially adapted for photographic purposes
• CPC Class Codes: G03B 17/12 with means for supporting objectives, supplementary lenses, filters, masks, or turrets
• CPC Class Codes: G03B 17/14 interchangeably

Abstract

An optical system is arranged on an object side relative to a first optical portion, the first optical portion including a plurality of lens portions each configured to form an image of an object, and a plurality of filters corresponding to the plurality of lens portions, and the optical system includes a second optical portion including an optical surface common to the plurality of lens portions, wherein the following conditional expression is satisfied:

$\frac{1}{2}\times \arctan \left\{\frac{2\times \tan \omega 1-\frac{\Delta h1}{D1}}{1-\tan \omega 1\times \left(\tan \omega 1-\frac{\Delta h1}{D1}\right)}\right\}<\theta 1.$

Claims

1. An optical system arranged on an object side relative to a first optical portion, the first optical portion including a plurality of lens portions each configured to form an image of an object, and a plurality of filters corresponding to the plurality of lens portions, the optical system comprising:

a second optical portion including an optical surface common to the plurality of lens portions,

wherein the following conditional expression is satisfied;

2. The optical system according to claim 1, further comprising a first light-shielding member arranged between the first filter and the second filter within the same plane as the first filter and the second filter and configured to shield the light beam reflected at the second point.

3. The optical system according to claim 1, further comprising a second light-shielding member arranged at a position farther from the optical axis than the plurality of filters is and configured to shield the light beam reflected at the second point.

4. The optical system according to claim 1, wherein in a direction vertical to the optical axis, an incident point of the light beam from the object farthest from the optical axis in the first filter is positioned within a range from a center of the first filter to an edge of the first filter closer to the optical axis.

5. The optical system according to claim 1, wherein the following conditional expression is satisfied:

R<

h11/tanω

1−

d1,

where R is a curvature radius of the optical surface at the second point; and

d1 is a distance to the first filter from a virtual spherical surface of a curvature radius R including the second point.

6. The optical system according to claim 1, wherein the light beam incident on the first point is an outermost off-axis ray.

7. The optical system according to claim 1, wherein an effective diameter of the second filter is smaller than an effective diameter of the first filter.

8. The optical system according to claim 1, wherein a central wavelength in a transmission wavelength range of the first filter is longer than a central wavelength in a transmission wavelength range of the second filter.

9. The optical system according to claim 1, wherein the first filter is arranged at a position farthest from the optical axis among the plurality of filters.

10. The optical system according to claim 1, wherein the optical surface is an optical surface arranged at a position closest to the plurality of filters among optical surfaces having power and arranged on the object side relative to the plurality of filters.

11. The optical system according to claim 1, wherein the optical surface includes an antireflection structure.

12. The optical system according to claim 1, wherein the following conditional expression is satisfied:

13. The optical system according to claim 12, wherein the following conditional expression is satisfied:

1.0×

10<sup>−

3</sup><

d2/h21<

2.0,

where d2 is a distance from the optical surface on the optical axis to the second filter.

14. The optical system according to claim 1, wherein an optical surface adjacent to an object side of the optical surface has a convex shape toward an image side.

15. The optical system according to claim 1, wherein the second optical portion converts light from the object into parallel light.

17. An accessory apparatus comprising the optical system according to claim 1, wherein the accessory apparatus is detachably attachable to an imaging apparatus.

18. An imaging apparatus comprising:

an optical system according to claim 1; and

an image sensor configured to receive light from the optical system.

19. The imaging apparatus according to claim 18, wherein the image sensor is common to the plurality of lens portions.

20. The imaging apparatus according to claim 18, wherein a sensitivity of the image sensor with respect to a central wavelength in a transmission wavelength range of the second filter is higher than a sensitivity with respect to a central wavelength in a transmission wavelength range of the first filter.

16. An optical system arranged on an object side relative to a first optical portion is, the first optical portion including a plurality of lens portions each configured to form an image of an object, and a plurality of filters corresponding to the plurality of lens portions, the optical system comprising:

a second optical portion including an optical surface common to the plurality of lens portions,

wherein the following conditional expression is satisfied;