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US5737084A
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US
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Three-dimensional shape measuring apparatus
Assignee: TAKAOKA ELECTRIC MTG CO Ltd
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Filing: 1996-09-26
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Granted: 1998-04-07
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Expires: 2016-09-26
Abstract
Abstract A three-dimensional shape measuring apparatus which has an improved arrayed confocal imaging system. A three-dimensional shape measuring apparatus using a confocal imaging system which has a new means for changing the distance in the Z direction between the object and the object-position-in-focus, instead of an object stage moved in the Z direction. This means shifts the object-position-in-focus in the Z direction by refraction. One means inserts a plurality of transparent flat plates between the objective lens and the object-position-in-focus in turn. Another means uses a transparent flat plate made of a material for which the refractive index changes according to the voltage applied and is disposed between the object and the object-position-in-focus. A three-dimensional shape measuring apparatus using a confocal imaging system wherein an image processor estimates the position from which the intensity of the reflected light for each pixel of the confocal image becomes maximum by interpolation of a value from the curve of the relationship between the intensity of light detected and the distance from the object-position-in-focus to an object point.
Inventors
- 👤 Mitsuhiro Ishihara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 11:24
CPC Classifications
G; G01; G01B; G01B11/00; G01B11/24; G01B11/02; G01B11/026
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
312 words
A three-dimensional shape measuring apparatus using an arrayed confocal imaging system comprising: an arrayed confocal imaging system; means for changing the relative distance in the Z direction between an object and the object-position-in-focus; and an image processor which calculates the three-dimensional shape of the object from confocal images acquired at different relative distances in the Z direction between an object and the object-position-in-focus by the arrayed confocal imaging system and the means for changing the relative distance in the Z direction between an object and the object-position-in-focus; characterized in that said arrayed confocal imaging system comprises: a light source which emits illuminating light; a light path diverging optical element which causes the path of the illuminating light and the path of the reflected light to diverge; a microlens array provided with a large number of two-dimensionally arranged microlenses each of which converges the illuminating light coming out from the light path diverging optical element into a small spot; a pinhole array provided with a large number of pinholes which are disposed at the focal point of the corresponding microlenses of the microlens array; an objective lens which converges the illuminating light that passes through the pinholes of the pinhole array toward an object and converges the reflected light from the object toward the pinhole array; a two-dimensional photoelectric sensor which receives the reflected light that passes through the pinholes of the pinhole array and then through the corresponding microlenses of the microlens array and is deflected thereto by the light path diverging optical element, and converts the received light into electricity of an amount proportional to the intensity of the received light; and an image forming section which is disposed between the light path diverging optical element and the two-dimensional photoelectric sensor to form an image of the microlenses of the microlens array on the corresponding elements of the two-dimensional photoelectric sensor.
Claim 2
Dependent Claim
312 words
A three-dimensional shape measuring apparatus using an arrayed confocal imaging system comprising: an arrayed confocal imaging system; means for changing the relative distance in the Z direction between an object and the object-position-in-focus; and an image processor which calculates the three-dimensional shape of the object from confocal images acquired at different relative distances in the Z direction between an object and the object-position-in-focus by the arrayed confocal imaging system and the means for changing the relative distance in the Z direction between an object and the object-position-in-focus; characterized in that said arrayed confocal imaging system comprises: a light source which emits illuminating light; a light path diverging optical element which causes the path of the illuminating light and the path of the reflected light to diverge; a microlens array provided with a large number of two-dimensionally arranged microlenses each of which converges the illuminating light coming out from the light path diverging optical element into a small spot; a pinhole array provided with a large number of pinholes which are disposed at the focal point of the corresponding microlenses of the microlens array; an objective lens which converges the illuminating light that passes through the pinholes of the pinhole array toward an object and converges the reflected light from the object toward the pinhole array; a two-dimensional photoelectric sensor which receives the reflected light that passes through the pinholes of the pinhole array and then through the corresponding microlenses of the microlens array and is deflected thereto by the light path diverging optical element, and converts the received light into electricity of an amount proportional to the intensity of the received light; and an image forming section which is disposed between the light path diverging optical element and the two-dimensional photoelectric sensor to form an image of the microlenses of the microlens array on the corresponding elements of the two-dimensional photoelectric sensor.
Claim 3
Dependent Claim
77 words
The three-dimensional shape measuring apparatus using an arrayed confocal imaging system of claim 1 wherein a spatial-frequency filtering means for limiting the spatial frequencies of the image of said microlens array formed by said image forming section on said two-dimensional photoelectric sensor equal to or smaller than 1/2 of the spatial frequency of the array of the photoelectric elements of said two-dimensional photoelectric sensor is further disposed between said two-dimensional photoelectric sensor and said image forming section.
Claim 4
Dependent Claim
30 words
The three-dimensional shape measuring apparatus using an arrayed confocal imaging system of claim 1 or 2 wherein the shape of the microlenses of said microlens array is hexagonal or rectangular.
Claim 5
Dependent Claim
89 words
The three-dimensional shape measuring apparatus using an arrayed confocal imaging system of claim 1, or 2 which further comprises a polarizer which is disposed between said light source and said light path diverging optical element to polarize the illuminating light emitted from said light source into linearly polarized light, a 1/4 wavelength plate disposed between said microlens array and an object, and an analyzer disposed between said microlens array and said two-dimensional photoelectric sensor in an orientation so as to form an orthogonal nicol with respect to said polarizer.
Claim 6
Dependent Claim
27 words
The three-dimensional shape measuring apparatus using an arrayed confocal imaging system of claim 1, or 2 wherein said light path diverging optical element is a dichroic mirror.
Claim 7
Dependent Claim
87 words
The three-dimensional shape measuring apparatus using an arrayed confocal imaging system of claim 3 which further comprises a polarizer which is disposed between said light source and said light path diverging optical element to polarize the illuminating light emitted from said light source into linearly polarized light, a 1/4 wavelength plate disposed between said microlens array and an object, and an analyzer disposed between said microlens array and said two-dimensional photoelectric sensor in an orientation so as to form an orthogonal nicol with respect to said polarizer.
Claim 8
Dependent Claim
24 words
The three-dimensional shape measuring apparatus using a confocal imaging system of claim 3 wherein said light path diverging optical element is a dichroic mirror.
References Cited (Backward Citations)
JPH07181023A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-04-06 | 2001-10-06 | 2002-04-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-04-06 | 2005-10-06 | 2006-04-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-04-06 | 2009-10-06 | 2010-04-07 | $7700.00 | Window Closed / Lapsed |