公开(公告)号：EP3959508A1

公开(公告)日：2022-03-02

申请号：EP20720073.4

申请日：2020-04-24

Applicant: Lambda-X

Inventor： ANTOINE, Philippe ,  BEGHUIN, Didier ,  JOANNES, Luc

IPC: G01N21/45 ,  G02B27/54 ,  G01M11/02

公开(公告)号：EP2212681A1

公开(公告)日：2010-08-04

申请号：EP08852427.7

申请日：2008-11-06

Applicant: Lambda-X

Inventor： BEGHUIN, Didier ,  JOANNES, Luc

IPC: G01N21/956 ,  G01B11/25 ,  G01M11/02

CPC classification number: G01N21/95623 ,  G01B11/25 ,  G01M11/0264 ,  G01M11/0278

Abstract: The present invention relates to a Fourier transform deflectometry system (1) and method for the optical inspection of a phase and amplitude object (2) placed in an optical path between a grating (3) and an imaging system (4), at a distance h of said grating 3. The grating (3) forms a contrast-based periodic pattern with spatial frequencies μ0, v0 in, respectively, orthogonal axes x,y in an image plane, and the imaging system (4) comprises an objective (5) and an imaging sensor (6) comprising a plurality of photosensitive elements. Spatial frequencies μ0, v0 are equal or lower than the Nyquist frequencies of the imaging system in the respective x and y axes. According to the method of the invention, a first image of said pattern, distorted by the phase and amplitude object (2), is first captured through the objective (5) by the imaging sensor (6). Then, a Fourier transform of said first image in a spatial frequency domain is calculated, at least one first- or higher-order spectrum of said Fourier transform is selected and shifted in said frequency domain, so as to substantially place it at a central frequency of said Fourier transform, and a reverse Fourier transform of said at least one shifted first- or higher-order spectrum of said Fourier transform is performed so as to obtain a complex function g(x,y)=l(x,y)eiφ(x,y), wherein l(x,y) is an intensity and φ(x,y) a phase linked to optical deflection angles ϑx, ϑy in, respectively, the directions of the x and y axes, in the following form: φ(x,y)=- 2ττh(μ0tanϑx+v0tanϑy).

Abstract translation: 本发明涉及一种傅里叶变换折射系统（1）和用于光学检查放置在光栅（3）和成像系统（4）之间的光路中的相位和振幅物体（2）的方法， 所述光栅3形成基于对比度的周期性图案，所述周期性图案分别在图像平面中具有正交轴x，y，并且所述成像系统（4）包括物镜（5） ）和包括多个光敏元件的成像传感器（6）。 空间频率μ0，v0等于或低于成像系统在各个x轴和y轴上的奈奎斯特频率。 根据本发明的方法，首先通过成像传感器（6）通过物镜（5）捕获由相位和幅度物体（2）失真的所述图案的第一图像。 然后，计算空间频率域中的所述第一图像的傅里叶变换，选择所述傅立叶变换的至少一个一阶或更高阶谱并在所述频域中移位，从而基本上将其置于中心频率 并且对所述傅立叶变换的所述至少一个移位的一阶或更高阶谱进行傅里叶逆变换以便获得复函数g（x，y）= 1（x，y）eiφ （x，y），其中l（x，y）是分别与x和y轴的方向相关联的光学偏转角度θx，θv，y的强度和φ（x，y） 以下面的形式：φ（x，y）=-2ττh（μ0tan＆thetav; x + v0tan＆thetav; y）。