US3740152A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for detecting the boundary between different brightness regions of an object
Assignee: Nikon Corp
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Filing: 1971-06-23
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Granted: 1973-06-19
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Expires: 1991-06-23
Abstract
Abstract A device for automatically determining the position of a boundary between light and dark regions of an object such as an IC mask pattern or the like, the device including an optical system for forming a point or line symmetrical double image, a light beam modulator means for providing a position signal from an image formed through said optical system, a photoelectric converter means for converting a light signal modulated by the light beam modulator means into an electrical signal, and a phase detector means for converting the electrical signal from the photoelectric converter into a DC signal, whereby the position of the boundary may be determined in a highly accurate and stable manner irrespective of any relatively great or small brightness and difference between the light and dark regions of the object, and without any adverse effect resulting from such variable factors as the variation in brightness of the image, the aging of the detector element and operator errors.
Inventors
- 👤 K Iisuka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 14:11
CPC Classifications
G; G03; G03F; G03F9/00; G03F9/70; G01; G01D; G01D5/00; G01D5/26
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
92 words
A device for determining the position of a boundary between different brightness regions of an object, comprising: an optical system for forming a symmetrical double image of an object; light beam modulator means for producing a light signal from said image formed through said optical system; photoelectric converter means for converting said light signal modulated by said light beam modulator means into an electrical signal; and phase detector means coupled to said modulator means and said converter means for converting said electrical signal from said photoelectric converter means into a DC signal.
Claim 2
Independent Claim
92 words
A device for determining the position of a boundary between different brightness regions of an object, comprising: an optical system for forming a symmetrical double image of an object; light beam modulator means for producing a light signal from said image formed through said optical system; photoelectric converter means for converting said light signal modulated by said light beam modulator means into an electrical signal; and phase detector means coupled to said modulator means and said converter means for converting said electrical signal from said photoelectric converter means into a DC signal.
Claim 3
Dependent Claim
40 words
A device as defined in claim 1, wherein said light beam modulator means comprises a scanning slit plate formed with a scanning slit for passing therethrough a light beam from said object, and a vibrator for vibrating said slit plate.
Claim 4
Dependent Claim
39 words
A device as defined in claim 2, wherein said scanning slit plate moves reciprocally in one direction and said scanning slit extends perpendicularly to the scanning direction of said slit plate and parallel to the boundary of said object.
Claim 5
Dependent Claim
44 words
A device as defined in claim 2, wherein said modulator means further comprises a reference oscillator, and wherein said scanning slit plate is vibrated by said vibrator in synchronism with a signal of a predetermined frequency applied to said vibrator by said reference oscillator.
Claim 6
Dependent Claim
42 words
A device as defined in claim 2, wherein said modulator means further comprises means for applying an electrical signal of predetermined frequency to said vibrator, and wherein said scanning slit plate is vibrated by said vibrator in synchronism with said predetermined frequency.
Claim 7
Dependent Claim
37 words
A device as defined in claim 1, wherein said light beam modulator means comprises a scanning slit plate formed with a scanning slit and a vibrating mirror for vibrating a light beam passed through said scanning slit.
Claim 8
Dependent Claim
42 words
A device as defined in claim 1, further comprising an AC amplifier for amplifying the electrical signal from said photoelectric converter means, and an indicating meter for indicating the DC signal from said phase detector means representing the position of said boundary.
Claim 9
Independent Claim
138 words
A device for determining the position of a boundary between different brightness regions of an object, comprising: an optical system for forming a symmetrical double image of said object; means for generating a signal of a predetermined frequency; scanning means connected to said signal generating means for scanning said image formed through said optical system in synchronism with said signal from said signal generating means to thereby provide a positional signal representing the position of the boundary; photoelectric converter means for converting said positional signal into an electric signal; and phase detector means coupled to said photoelectric converter means and to said signal generating means for using said signal from said signal generating means as a reference signal to convert said electrical signal from said photoelectric converter means into a D.C. signal representing the position of said boundary.
Claim 10
Independent Claim
138 words
A device for determining the position of a boundary between different brightness regions of an object, comprising: an optical system for forming a symmetrical double image of said object; means for generating a signal of a predetermined frequency; scanning means connected to said signal generating means for scanning said image formed through said optical system in synchronism with said signal from said signal generating means to thereby provide a positional signal representing the position of the boundary; photoelectric converter means for converting said positional signal into an electric signal; and phase detector means coupled to said photoelectric converter means and to said signal generating means for using said signal from said signal generating means as a reference signal to convert said electrical signal from said photoelectric converter means into a D.C. signal representing the position of said boundary.
Claim 11
Independent Claim
104 words
A device for determining the relative positions of a reference line and a boundary between different brightness regions of an object, comprising: an optical system for forming a symmetrical double image of an object; light beam position modulator means for producing a light signal from said image, wherein said light signal is position modulated with respect to said reference line; photoelectric converter means for converting said light signal into an electrical signal; and phase detector means coupled to said modulator means and said converter means for providing an output signal which is proportiOnal to the position of said boundary relative to said reference line.
Claim 12
Independent Claim
104 words
A device for determining the relative positions of a reference line and a boundary between different brightness regions of an object, comprising: an optical system for forming a symmetrical double image of an object; light beam position modulator means for producing a light signal from said image, wherein said light signal is position modulated with respect to said reference line; photoelectric converter means for converting said light signal into an electrical signal; and phase detector means coupled to said modulator means and said converter means for providing an output signal which is proportiOnal to the position of said boundary relative to said reference line.
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) | 1976-06-18 | 1976-12-18 | 1977-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-18 | 1980-12-18 | 1981-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-18 | 1984-12-18 | 1985-06-19 | $7700.00 | Window Closed / Lapsed |