US3589815A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Noncontact measuring probe
Assignee: INFORMATION DEV CORP
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Filing: 1968-06-21
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Granted: 1971-06-29
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Expires: 1988-06-21
Abstract
Abstract A noncontacting optical probe capable of giving a continuous reading of the distance from a given reference to a contoured surface. A collimated beam is directed parallel to the optical axis of a fixed objective lens whose optical axis defines a measuring axis. The beam is deviated at a slight angle towards the surface to be measured, with the angle defining a projection axis. A lens assembly focuses the collimated beam to a very small diameter image point in front of the objective lens on the measuring axis. Translation of the lens assembly causes the image point to move along the measuring axis a distance equal to the movement of the assembly. The spot is not defocused along the axis. The light reflected from the surface is collected by the objective lens, directed through a filter and focused towards a prism lying in the focal plane of the lens. The prism is a 90* prism with the faces forming the 90* angle brought to a sharp edge at the focal plane of the lens. The amount of light reflected from the respective surfaces of the 90* angle are detected by photocells. The movement of the lens assembly is measured, and compared with the point at which the amount of light detected by the two photocells is equal and above a predetermined value. The distance from the lens assembly to the surface is measured at this instant. Linear reading can be presented in digital form with a resolution of 0.0001 inch, and to an accuracy of 0.0001 if desired.
Inventors
- 👤 Harry L Hosterman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:22
CPC Classifications
G; G01; G01B; G01B11/00; G01B11/24; G01B11/02; G01B11/026
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
184 words
A noncontact probe to measure surface distances from a predetermined reference which comprises means to produce a directed beam of light energy having an axis, first lens means defining an optical measuring axis parallel to the axis of the directed beam of light energy, optical redirecting means including second lens means to angle the light beam from its axis at between about 5* to about 25* and focus the beam to a point at such angled relationship where the point falls on the axis of the first lens means, means to move the point in focus parallel to the axis of the directed beam of light energy and coincident with the optical axis of the first lens means so that at some time the point is in focus on the surface, means aligned with the optical axis of the first lens means on the opposite side thereof from the surface to detect when the point is in focus on the surface, and reference means to coordinate the movement of the point with the means to detect to measure the distance of the surface therefrom.
Claim 2
Dependent Claim
184 words
A noncontact probe to measure surface distances from a predetermined reference which comprises means to produce a directed beam of light energy having an axis, first lens means defining an optical measuring axis parallel to the axis of the directed beam of light energy, optical redirecting means including second lens means to angle the light beam from its axis at between about 5* to about 25* and focus the beam to a point at such angled relationship where the point falls on the axis of the first lens means, means to move the point in focus parallel to the axis of the directed beam of light energy and coincident with the optical axis of the first lens means so that at some time the point is in focus on the surface, means aligned with the optical axis of the first lens means on the opposite side thereof from the surface to detect when the point is in focus on the surface, and reference means to coordinate the movement of the point with the means to detect to measure the distance of the surface therefrom.
Claim 3
Dependent Claim
36 words
A probe according to claim 1 where a laser is utilized for the beam of light energy, and the beam axis parallel to the optical axis of the first lens is substantially normal to the surface.
Claim 4
Dependent Claim
53 words
A probe according to claim 1 which includes the sharp edge of a right angular silvered prism coincident with the optical axis of the first lens means of the opposite side thereof from the surface with the faces of the prism at substantially 45* relation to the plane of the first lens means.
Claim 5
Dependent Claim
59 words
A probe according to claim 3 where the means to detect is a pair of photodiodes each mounTed at a similar angular spacing and distance with respect to a respective face of the prism so as to measure the light beam impinging thereon, and a comparator receiving the signals from each photodiode to determine when the signals are equal.
Claim 6
Dependent Claim
130 words
A probe according to claim 4 where the means to record the contours of the surface comprises Pi means to move the redirecting means in a direction coincident with the axis of the beam, a fixed slotted grid, a movable slotted grid connected to the second lens means and positioned adjacent the fixed slotted grid, and each grid having similarly spaced slots substantially aligned in their adjacent relationship whereby the movement of the second lens means causes movement of the movable slotted grid in a direction substantially normal to the direction of the slots therein, and radiation means directed through the grids, and means to detect the radiation passing through the grids to measure the amount and direction of movement of the movable slotted grid to the fixed slotted grid.
Claim 7
Dependent Claim
44 words
A probe according to claim 5 where each of the grids includes a single center position slot, a group of quadrature slots to determine direction of movement, and measuring slots spaced at about 0.001-inch intervals to measure the distance from the center position slot.
Claim 8
Dependent Claim
36 words
A probe according to claim 6 where the means to move the focused point is a tuned spring connected to the redirecting means, and includes other means to drive the spring at a predetermined resonant frequency.
Claim 9
Dependent Claim
45 words
A noncontact probe according to claim 1 which includes an optical system associated with the second lens means whereby physical movement of the second lens means is at least doubled in the movement of the focused point on the axis of the first lens means.
Claim 10
Dependent Claim
136 words
A noncontact probe which comprises means defining an optical measuring axis in space, means to generate a beam of light energy having an axis, means to focus and bend the beam off its axis and direct the bent portion to a focused point in space on the measuring axis, means to move the last-said means along an axis in space relative to a reference so that the point intersects a surface to be measured at some time during its movement, said axis being parallel to the measuring axis, means to detect when the point intersects a surface to be measured in focus by viewing along the measuring axis, and means to measure the distance of the point with respect to the reference at the instant the point is in focus on the surface to be measured.
Claim 11
Dependent Claim
136 words
A noncontact probe which comprises means defining an optical measuring axis in space, means to generate a beam of light energy having an axis, means to focus and bend the beam off its axis and direct the bent portion to a focused point in space on the measuring axis, means to move the last-said means along an axis in space relative to a reference so that the point intersects a surface to be measured at some time during its movement, said axis being parallel to the measuring axis, means to detect when the point intersects a surface to be measured in focus by viewing along the measuring axis, and means to measure the distance of the point with respect to the reference at the instant the point is in focus on the surface to be measured.
Claim 12
Dependent Claim
35 words
A probe according to claim 9 where the beam is bent at an angle of at least 5* from its axis, and where the measuring axis is substantially perpendicular to the surface to be measured.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-06-28 | 1974-12-28 | 1975-06-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-28 | 1978-12-28 | 1979-06-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-28 | 1982-12-28 | 1983-06-29 | $7700.00 | Window Closed / Lapsed |