Patent US4597669A successfully refreshed from Google Patents.
US4597669A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pattern detector
Assignee: Hitachi Ltd
•
Filing: 1983-10-07
•
Granted: 1986-07-01
•
Expires: 2003-10-07
Abstract
Abstract A pattern detector according to the present invention adopts a processing method wherein means is provided anew with which the intensity distribution of light reflected from or transmitted through an illuminated specimen is photoelectrically converted, and a pattern position is detected at high speed from the ratio between the primary moment and integral value of a detection signal thus derived, whereupon a symmetry calculation is executed within a narrow range around the detected value, whereby the pattern position is found fast and precisely.
Inventors
- 👤 Tsuneo Terasawa
- 👤 Shinji Kuniyoshi
- 👤 Akihiro Takanashi
- 👤 Toshiei Kurosaki
- 👤 Yoshio Kawamura
- 👤 Sumio Hosaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 09:54
CPC Classifications
G; G03; G03F; G03F9/00; G03F9/70; H; H10; H10P; H10P95/00
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
127 words
A pattern detector comprising: a detection signal deriving portion in which a specimen is illuminated, whereupon an intensity distribution of light reflected from or transmitted through the specimen is photoelectrically converted and then derived as a detection signal; and a processing portion which executes signal processing for measuring a specimen position from the derived detection signal; wherein said processing portion comprises (a) means for calculating a centroid of the detection signal, including means for calculating a primary moment of the detection signal, means for calculating an integral value of the detection signal, and means for dividing the primary moment by the integral value; and (b) a symmetry calculating portion which detects the specimen position near the centroid of the detection signal calculated by said centroid calculating means.
Claim 2
Dependent Claim
127 words
A pattern detector comprising: a detection signal deriving portion in which a specimen is illuminated, whereupon an intensity distribution of light reflected from or transmitted through the specimen is photoelectrically converted and then derived as a detection signal; and a processing portion which executes signal processing for measuring a specimen position from the derived detection signal; wherein said processing portion comprises (a) means for calculating a centroid of the detection signal, including means for calculating a primary moment of the detection signal, means for calculating an integral value of the detection signal, and means for dividing the primary moment by the integral value; and (b) a symmetry calculating portion which detects the specimen position near the centroid of the detection signal calculated by said centroid calculating means.
Claim 3
Dependent Claim
39 words
A pattern detector as defined in claim 1, wherein said detection signal deriving portion includes an A/D converter which converts a photoelectric signal into a digital value, and a memory which stores the value of the A/D-converted detection signal.
Claim 4
Dependent Claim
54 words
A pattern detector as defined in claim 2, wherein said primary moment calculating means includes a multiplier circuit which multiplies the value of the signal stored in said memory and a counter value indicative of an address of said memory which stores the detection signal, and an adder circuit which adds the multiplied results.
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) | 1989-06-30 | 1989-12-30 | 1990-07-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-06-30 | 1993-12-30 | 1994-07-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-06-30 | 1997-12-30 | 1998-07-01 | $7700.00 | Window Closed / Lapsed |