US3721759A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of and device for the automatic focusing of microscopes
Assignee: Carl Zeiss AG
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Filing: 1971-02-11
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Granted: 1973-03-20
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Expires: 1991-02-11
Abstract
Abstract The invention contemplates a method and means whereby critical focus can be automatically achieved in a microscope, using TV scanning of the imaged object while the focused condition of the microscope is varied. As its criterion for critical focus, the invention in a preferred form uses a minimum-length or a minimumarea evaluation, while the fine-focus mechanism of the microscope is being driven, continuously and at constant speed. As soon as the television system indicates that the minimum of the measuring signal has been reached, the fine-focus drive is terminated. The microscope is then critically focused.
Inventors
- 👤 W Lang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:13
CPC Classifications
G; G02; G02B; G02B21/00; G02B21/24; G02B21/241; G02B21/244; G03; G03B; G03B21/00; G03B21/14; G03B21/53
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
129 words
The method of focusing a microscope having an objectsupporting stage transverse to the axis of thE microscope objective, and having means for adjusting the relative axial position between the stage and the objective, which method comprises the steps of first roughly making such adjustment while observing a selected portion of the image of the object, then refining the adjustment by scanning the image portion by television means and generating a signal which is proportional to the length or area of the selected image portion, driving the adjusting means through a range of positions commencing on one defocused side of and in the direction toward the roughly determined focus position, such drive being concurrent with the scanning to generate said signal, continuing said drive until said signal reaches minimum value.
Claim 2
Independent Claim
129 words
The method of focusing a microscope having an objectsupporting stage transverse to the axis of thE microscope objective, and having means for adjusting the relative axial position between the stage and the objective, which method comprises the steps of first roughly making such adjustment while observing a selected portion of the image of the object, then refining the adjustment by scanning the image portion by television means and generating a signal which is proportional to the length or area of the selected image portion, driving the adjusting means through a range of positions commencing on one defocused side of and in the direction toward the roughly determined focus position, such drive being concurrent with the scanning to generate said signal, continuing said drive until said signal reaches minimum value.
Claim 3
Dependent Claim
18 words
The method of claim 1, including the step of terminating the drive when said signal reaches minimum value.
Claim 4
Dependent Claim
41 words
The method of claim 1, in which only those portions of the video signal of the television-scanning means which exceed a preselected threshold value are used to generate said signal proportional to the length or area of the selected image portion.
Claim 5
Dependent Claim
37 words
The method of claim 1, including the step of differentiating with respect to time the signal proportional to the length or area of the selected image portion, said drive continuing until the differentiated signal reaches zero value.
Claim 6
Dependent Claim
17 words
The method of claim 1, in which said traverse is made continuously and at substantially constant speed.
Claim 7
Dependent Claim
164 words
In combination, a microscope having an object-supporting stage transverse to the axis of the microscope objective and having focusing means for adjusting the relative axial position between the stage and the objective, and a closed-circuit television system including a TV camera positioned to scan the image field of the microscope, means for adjusting the relative transverse position of the stage and objective axis to enable selection of an object to be evaluated in said field, said television system including means periodically scanning said field and developing an electrical signal for a scanned lineal dimension of an object in said field, said focusing means including a fine-focus drive operative to adjust said relative axial position from a defocused relation and in the direction of a focused relation; whereby, in the course of operating said fine-focus drive, said electrical signal reduces in magnitude in approach to the focused relation; and means for terminating said fine-focus drive upon attainment of a minimum amplitude of said electrical signal.
Claim 8
Dependent Claim
164 words
In combination, a microscope having an object-supporting stage transverse to the axis of the microscope objective and having focusing means for adjusting the relative axial position between the stage and the objective, and a closed-circuit television system including a TV camera positioned to scan the image field of the microscope, means for adjusting the relative transverse position of the stage and objective axis to enable selection of an object to be evaluated in said field, said television system including means periodically scanning said field and developing an electrical signal for a scanned lineal dimension of an object in said field, said focusing means including a fine-focus drive operative to adjust said relative axial position from a defocused relation and in the direction of a focused relation; whereby, in the course of operating said fine-focus drive, said electrical signal reduces in magnitude in approach to the focused relation; and means for terminating said fine-focus drive upon attainment of a minimum amplitude of said electrical signal.
Claim 9
Dependent Claim
41 words
The combination of claim 6, in which said last-defined means includes differentiating means connected to respond to said electrical signal, and means responsive to attainment of a zero value in the output of said differentiating means for terminating said fine-focus drive.
Claim 10
Dependent Claim
35 words
The combination of claim 6, in which means including a limit switch at said microscope determines a starting position of said fine-focus drive, said limit switch being positioned for a defocused condition at said plane.
Claim 11
Dependent Claim
45 words
The combination of claim 8, in which said last-defined means includes a second limit switch at said microscope determining a terminal position of said fine-focus drive, said second limit switch being positioned for a defocused condition at said plane, with critical focus between said positions.
Claim 12
Dependent Claim
18 words
The combination of claim 6, and including stop means limiting the object image supplied at said image plane.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-19 | 1976-09-18 | 1977-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-19 | 1980-09-18 | 1981-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-19 | 1984-09-18 | 1985-03-20 | $7700.00 | Window Closed / Lapsed |