US3661440A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Microscope for inspecting surfaces of holes or the like
Assignee: Nikon Corp
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Filing: 1970-02-12
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Granted: 1972-05-09
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Expires: 1990-02-12
Abstract
Abstract A microscope especially adapted to inspect the surfaces of holes or the like is provided. A group of objectives having shorter focal lengths and including at least one objective having a magnification less than one-half in order to form an image reduced in size is combined with an eyepiece having a shorter focal length, thereby forming a magnified image. Because of the difference in magnifications at both ends of an increased depth of field, the image is exceedingly distorted so as to permit the inspection of surfaces of holes or the like.
Inventors
- 👤 Kinji Takahashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 00:32
CPC Classifications
G; G02; G02B; G02B23/00; G02B23/24; G02B23/2407; G02B21/00
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
139 words
A microscope optical system for observing the inner surface of a hole, which comprises: a group of objectives forming a final image of an object reduced in size as compared with the object, said group including a first objective for forming a first intermediate image of the object and a second objective for forming a second intermediate image, said first objective having a shorter focal length than a half of that of said second objective and located in a relative position in which its magnification is less than onehalf to obtain large depth of focus and cause the difference in lateral magnification between the images at both ends of the depth of focus; and an eyepiece having a shorter focal length than that of said second objective, whereby the overall magnification of said optical system is larger than 1.
Claim 2
Dependent Claim
139 words
A microscope optical system for observing the inner surface of a hole, which comprises: a group of objectives forming a final image of an object reduced in size as compared with the object, said group including a first objective for forming a first intermediate image of the object and a second objective for forming a second intermediate image, said first objective having a shorter focal length than a half of that of said second objective and located in a relative position in which its magnification is less than onehalf to obtain large depth of focus and cause the difference in lateral magnification between the images at both ends of the depth of focus; and an eyepiece having a shorter focal length than that of said second objective, whereby the overall magnification of said optical system is larger than 1.
Claim 3
Dependent Claim
22 words
A microscope optical system according to claim 1 wherein said second objective has an aperture stop to adjust the depth of focus.
Claim 4
Dependent Claim
39 words
A microscope optical system according to claim 1, wherein the focal lengths of said first and second objectives and said eyepiece are 15 mm, 36.5 mm and 9 mm, respectively, the overall magnification of said optical system being 6.
Claim 5
Dependent Claim
39 words
A microscope optical system according to claim 1, wherein the focal lengths of said first and second objectives and said eyepiece are 8 mm, 36.5 mm and 9 mm, respectively, the overall magnification of said optical system being 2.5.
Claim 6
Dependent Claim
39 words
A microscope optical system according to claim 1, wherein the focal lengths of said first and second objectives and said eyepiece are 4.3 mm, 36.5 mm and 9 mm, respectively, the overall magnification of said optical system being 1.5.
References Cited (Backward Citations)
US1458143A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-09 | 1975-11-08 | 1976-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-09 | 1979-11-08 | 1980-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-09 | 1983-11-08 | 1984-05-09 | $7700.00 | Window Closed / Lapsed |