EP0307029A1 Expired / Lapsed EP ⏱️ 0.0 years remaining

Apparatus for the point-by-point scanning of an object

Assignee: Koninklijke Philips NV

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Filing: 1988-08-26

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Granted: —

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Expires: 2008-08-26

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Abstract

Abstract A scanning microscope comprises a system (2, 3, 4) for concentrating a radiation beam from a radiation source (1) to form a scanning spot on an object (5). The radiation from the scanning spot is projected by a second optical system (6, 7) onto a radiation-sensitive detection system comprising two detectors (8, 9). The signals from the detectors (8, 9) are combined to a difference signal 11 and a sum signal 13. These two signals are combined to a complex composite signal which is transferred to the frequency domain in a circuit 22 via a Fourier transform. By performing suitable filtrations on the composite signal in the frequency domain in the circuit 23, quantitative measurements can be performed on the amplitude and phase structure of the object 5. These measurements may be visualized after an inverse Fourier transform in the circuit 24 via an image-processing system 25 on an image display unit 26.

Inventors

👤 Albert Smid

Bibliographic Details

Application Number —

Jurisdiction EP

Data Source google_patents

Last Synchronized 2026-11-03 14:37

CPC Classifications

G; G02; G02B; G02B21/00; G02B21/0004; G02B21/002; G02B27/00; G02B27/50

Claims Analysis

Total Claims: 6

Claim 1

Independent Claim 90 words

An apparatus for the point-by-point scanning of an object, which apparatus comprises a radiation source for supplying a scanning beam, an objective system for focussing the scanning beam to form a radiation spot on the object, a radiation-sensitive detection system for converting the radiation from the scanning spot into electric signals, and an electronic processing unit, said detection system comprising two radiation-sensitive detectors each supplying an electric signal, characterized in that the electronic processing unit is adapted to perform frequency-selective filtrations of a signal composed of the said electric signals.

Claim 2

Independent Claim 90 words

Claim 3

Dependent Claim 60 words

An apparatus as claimed in Claim 1, characterized in that the electronic processing unit is adapted to form the composite signal in accordance with S = S₁ + jS₂ in which S₁ is the composite signal, S₂ is a first real function and S is a second real function of the two electric signals and j is the imaginary unit.

Claim 4

Dependent Claim 35 words

An apparatus as claimed in Claim 2, characterized in that the first real function is the sum of the two electric signals and the second real function is the difference between the two electric signals.

Claim 5

Dependent Claim 46 words

An apparatus as claimed in Claim 1, 2 or 3, characterized in that the frequency-selective filtrations of the composite signal are effected in the frequency domain and in that the composite electric signal is converted to the frequency domain by means of a discrete Fourier transform.

Claim 6

Independent Claim 42 words

An apparatus as claimed in any one of the preceding Claims, characterized in that the electronic processing unit comprises a programmable computer which is suitable for storing instructions therein and for performing instructions for at least a part of the frequency-selective filtrations.

References Cited (Backward Citations)

US4446548A Cited

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