US 4,585,349 A · Method of and apparatus for determining the position of a device relative to a reference

Abstract

A method of and an apparatus for determining the location or position of a surface element with respect to a reference which utilizes polychromatic light and with a holographic lens on the light focuses individual wavelengths thereof to respective focal points at one of which the surface element can be located. Light reflected from this surface element is then decomposed into the respective wavelengths and the intensities of these wavelengths are analyzed to determine the wavelength of greatest intensity, this being the wavelength whose focus corresponds to the focus of the surface element. The maximum intensity wavelength is used to determine the position of this focus and hence the position of the surface element with respect to a reference.

Claims14

Dependent claims

A method of measuring the position of a surface element having at least a limited reflectivity capability, comprising the steps of:

generating a polychromatic light beam consisting of a plurality of rays of different wavelengths and substantially the same intensity;
focusing rays of respective wavelengths from said beam along a focal line at respective focal points, said elements lying along said line and reflecting light of at least several wavelengths including a wavelength of greater intensity corresponding to the wavelength whose focal point is substantially at the location of said element;
decomposing reflected light from said surface element into a spectrum of reflected wavelengths;
comparing the intensities of the light of the reflected wavelengths and ascertaining the wavelength of the compared intensities which is a maximum;
and
establishing from the determination of the wavelengths of the reflected light of maximum intensity the focal point thereof and hence the position of said element with respect to a reference.

3 more elements

Dependencies are inferred from the claim text.

Method of and apparatus for determining the position of a device relative to a reference

Life of this patent

Method of and apparatus for determining the position of a device relative to a reference

Life of this patent

Abstract

Claims14