WO1998013715B1 - Microscope generating a three-dimensional representation of an object - Google Patents

Abstract

The invention concerns a microscope comprising an optical part for generating interference figures between a reference light wave and a light wave diffracted by the observed object, sensors for digitising these interference figures, actuators for operating the optical system, and a computer for receiving the digitised interference figures, controlling the actuators, and provided with a memory and computing means for computing the three-dimensional images from the interference figures, based on a principle analogous to holography. The optical part enables the recording on a sensing surface (116) interference figures generated by a reference beam (Fr) and a beam (Fe) passing through a sample (109). The interference figures can differ from one another by the reference wave phase controlled by the piezoelectric actuator (120) or the spatial distribution of the illuminating beam controlled by the positioning device (106). This microscope can be used in biology or metrology.

Claims

 MODIFIED CLAIMS [received by the International Bureau on 24 April 1998 (24 04 98); original claims 1-12 replaced by modified claims 1-9 (1 page)] 1-Microscope numerically calculating a three-dimensional representation of an observed object, characterized in that said three-dimensional representation is calculated from the complex representation of a wave diffracted by the object and received on a receiving surface, thereby that said complex representation is itself obtained from several interference patterns formed on said receiving surface by the wave diffracted by the object and by a reference wave, and by the fact that said interference patterns differ between them by the phase difference between the wave illuminating the object and the reference wave 2-Mcrcroscope according to claim 1, characterized in that said reference wave is approximately spherical and centered, actually or virtually, at a central point of the observed area of the object 3-Mcrcroscope according to one of claims 1 or 2, characterized in that said phase difference between the reference wave and the wave illuminating the object is offset by 120 degrees between each of said interference figures 4-Mιcroscope according to one of claims 1 to 3, characterized in ^that an intermediate image is formed optically and spatially filtered by a diaphragm, and in that lenses are used to form from the intermediate image a figure of diffraction on the receiving surface 5-microscope according to one of claims 1 to 4, characterized in that in the absence of a reference wave a plane wave from the object produced on the receiving surface a point image 6-Mcrcroscope according to one of the claims 1 to 5, characterized by the fact that the wave illuminating the object is obtained by using a condenser forming on the object the image of a diffusing element illuminated by the laser beam 7-Mcrcroscope according to one of claims 1 to 6, characterized in that several of said three-dimensional representations, differing from each other by changes in the light illuminating the object, are used to obtemr an improved three-dimensional representation 8-Mcrcroscope according to claims 6 and 7, characterized in that said modifications of the wave illuminating the object are obtained by moving the diffusing element 9-Mcrcroscope according to one of claims 7 or 8, characterized in that said improved three-dimensional representation of the object observed is obtained by averaging intensity said three-dimensional representations differing from each other by changes in the wave illuminating the object -17- DECLARATION UNDER ARTICLE 19 Opposite antecedents concern numerical methods simulating optical holographic reconstruction. The prior art "Tmg-Chung Poon et Al" differs however as explained on page 1341 of the document cited. The traditional holographic recording includes the terms | 0 | + | R | + OR ^* +0 ^* R The first two terms constituting the second order term or spatially variable bias are removed in the method indicated by the author and the record is made as a real transmission function / ( x, v) representing the quantity OR +0 R A conventional holographic reconstruction is carried out from this quantity The present invention, according to the new claim 1, makes it possible to obtain the complex quantity O only which then serves as a basis for a reconstruction simulating the inverse return of light and not the optical holographic reconstruction. In the description of the invention, page 2 lines 26 to 29, it is indicated that the traditional holographic reconstruction method, used in the references "Karpov VB" "Bianco B and Al" and "Beltrame F and Al", leads to defects that are the appearance of a parasitic image and second-order deviations In the case of the "Ting-Chung Poon and Al" anteriority, the second-order deviations are eliminated but the parasite image remains the teaching of the present application, as indicated by page 2 lines 29 to 33, is that all of these defects can be eliminated by calculating the complex value of the wave on the receiving surface. The new claim 1 is limited to a microscope using this value wave complex It is also limited in specifying the manner of obtaining this complex value as indicated in the description, page 2 lines 33 to 35 This claim is therefore anténoπsee by none of the references cited in the research report The indications given in the description of the preferred embodiment, page 5 lines 5 to 7, mean that the reference wave is centered virtually in the center of the object being viewed. This embodiment corresponds to the new claim 1 The former claim 2 also covered the decedent embodiment of page 12 line 32 to page 13 line 27, which is no longer claimed, this part of the description thus becoming unnecessary The new claim 2 limits the former claim 2 by restricting it to the case of the new claim 1 and restricting the range in which the wave may be centered to the central area of the object in accordance with the preferred embodiment The "Karpov V B" anteriority concerns a traditional holographic reconstruction in which the reference wave must be centered out of the observed object, otherwise the parasite image is superimposed on the observed image. The new claim 2 is therefore not prejudiced, on the one hand because this claim is placed under claim 1, on the other hand because in "Karpov BV" 1 reference wave is not centered at a central point of the observed object but at a point close to said object The following claims reproduce with some modifications of the non-anteπoπsees claims already present in the text initially deposited