阅读说明：本技术 一种短相干泰曼干涉的色散补偿方法及测量装置 (Dispersion compensation method and measurement device for short-coherence Taman interference ) 是由 朱秋东 苑静 张喆民 王姗姗 刘彬 王伟志 于 2019-11-13 设计创作，主要内容包括：本发明提供了一种短相干泰曼干涉的色散补偿方法及测量装置。色散补偿方法为在短相干泰曼干涉仪中设置可旋转的细调补偿板和可更换的粗调补偿板,通过旋转细调补偿板改变其法线方向与所在光路光轴的夹角大小和更换不同厚度的粗调补偿板,实现参考光和测试光之间各波长光程差为零,进行色散补偿。本发明操作方便,可实现连续可调测量不同厚度透明平板样品的透射波像差。(The invention provides a dispersion compensation method and a measurement device for short-coherence Taman interference. The dispersion compensation method is that a rotatable fine adjustment compensation plate and a replaceable coarse adjustment compensation plate are arranged in the short-coherence Taemann interferometer, the size of an included angle between the normal direction of the fine adjustment compensation plate and the optical axis of the optical path is changed by rotating the fine adjustment compensation plate, the coarse adjustment compensation plates with different thicknesses are replaced, the optical path difference of each wavelength between reference light and test light is zero, and dispersion compensation is carried out. The invention has convenient operation and can realize continuous adjustable measurement of the transmitted wave aberration of the transparent flat plate samples with different thicknesses.)

1. A dispersion compensation method of short coherence Taman interference is characterized in that a rotatable fine tuning compensation plate and a replaceable coarse tuning compensation plate are arranged in a short coherence Taman interferometer, the size of an included angle between the normal direction of the fine tuning compensation plate and the optical axis of the optical path is changed by rotating the fine tuning compensation plate, the coarse tuning compensation plate with different thicknesses is replaced, the optical path difference of each wavelength between reference light and test light is zero, and dispersion compensation is carried out, wherein: the fine adjustment compensation plate and the coarse adjustment compensation plate have the same dispersion characteristic as the measured transparent flat plate sample.

2. The dispersion compensation method for short coherence Taman interference of claim 1, wherein the fine tuning compensation plate is disposed in a reference optical path of the short coherence Taman interferometer.

3. The method of dispersion compensation for short coherence Taman interference of claim 2, wherein the coarse tuning compensation plate is disposed in a reference optical path of the short coherence Taman interferometer.

4. The method of dispersion compensation for short coherence Taeman interference of claim 2, wherein the coarse tuning compensation plate is disposed in a test optical path of the short coherence Taeman interferometer.

5. The dispersion compensation method for short coherence Taman interference of claim 1, wherein the fine tuning compensation plate is disposed in a test optical path of the short coherence Taman interferometer and the coarse tuning compensation plate is disposed in a reference optical path of the short coherence Taman interferometer.

6. The method of dispersion compensation for short coherence Taeman interference according to any one of claims 1 to 5, wherein said coarse tuning compensation plate is a set of different thickness grading plates having a step difference of a mm, and said fine tuning compensation plate can compensate a maximum thickness variation of b mm, where a should not be greater than b.

7. A short coherent Taeman interference measuring device comprises a short coherent light source, a collimating mirror, a light splitting element, a first reference mirror, a second reference mirror, a condenser lens, an imaging lens and a camera, and is characterized by comprising a rotatable fine adjustment compensation plate and a replaceable coarse adjustment compensation plate; the light emitted by the short coherent light source is converted into parallel light by a collimating mirror, the parallel light is divided into reference light and test light by a light splitting element, the reference light is transmitted by a fine adjustment compensation plate, is reflected by a first reference mirror, returns along the original path, is reflected to an imaging light path by the light splitting element, is transmitted by a measured transparent flat plate sample, is reflected by a second reference mirror, returns along the original path, is transmitted to the imaging light path by the light splitting element, forms interference with the reference light returned to the imaging light path, is imaged to a camera target surface by an imaging lens, changes the size of an included angle between the normal direction of the fine adjustment compensation plate and the optical axis of the optical path by rotating the fine adjustment compensation plate and changes coarse adjustment compensation plates with different thicknesses, and is combined to realize that the optical path difference of each wavelength between the reference light and the test light is zero, so that the camera obtains a clear interference fringe image, and analyzes and calculates the interference fringe image, measuring the transmitted wave aberration of the measured transparent flat plate sample, wherein: the fine adjustment compensation plate and the coarse adjustment compensation plate have the same dispersion characteristic as the measured transparent flat plate sample.

8. A short coherence taemann interferometry device according to claim 7, wherein: the coarse adjustment compensation plate is a group of different thickness grading specification plates with the step difference of a mm, the maximum thickness variation amount which can be compensated by the fine adjustment compensation plate is b mm, and a is not larger than b.

9. A short coherence taeman interferometry device according to claim 7 or 8, wherein: the light splitting element is a light splitting prism.

10. A short coherence taeman interferometry device according to claim 7 or 8, wherein: the light splitting element is a combination of a light splitting plate and a light splitting plate compensation plate which has the same dispersion characteristic with the light splitting plate.

Technical Field

The invention relates to the technical field of short coherent light source interference measuring instruments, in particular to a dispersion compensation method and a measuring device for short coherent Taman interference.

Background

The basic principle of the short-coherence Taemann interferometer is that light emitted by a short-coherence light source forms parallel light beams through a collimating lens, the parallel light beams are divided into reference light and test light through a beam splitter prism, the reference light returns to the beam splitter prism along an original light path after being reflected by a first reference mirror, the reference light is reflected to an imaging light path through the beam splitter prism, the test light is transmitted by a measured transparent flat plate sample, the test light returns along the original path after being reflected by a second reference mirror, the test light is transmitted to the imaging light path through the beam splitter prism and forms interference with the reference light returned to the imaging light path, the test light is imaged to a camera target surface through an imaging lens, accurate measurement of the surface shape, the thickness, the wave aberration and the like of a measured transparent material is achieved through analysis of an interference pattern, and the schematic optical structure diagram of the.

The short-coherence Taeman interferometer has the advantages that the reference light path and the test light path are mutually separated, so that the reference light reflected by the first reference mirror and the test light reflected by the second reference mirror can generate interference by adjusting the distance between the first reference mirror or the second reference mirror and the beam splitter prism, and optical components can be flexibly increased, decreased and replaced in the light path. The short coherent light source has short coherence length, and can effectively avoid interference on an interference pattern acquired by a camera in an imaging light path due to interference of light returned by the front surface of the measured transparent material and reference light and interference of light returned by the rear surface of the measured transparent material and the reference light respectively.

However, the short coherence Taeman interferometer needs to take into account dispersion compensation between the reference light and the test light. For example, the chinese patent ZL201810061382.7 proposes a phase defect detection system and method based on a short coherent dynamic taemann-green interferometer, in which a rectangular light splitting element is used to make the optical path difference of each wavelength between the test light and the reference light zero, so as to perform dispersion compensation. The scheme does not consider the dispersion compensation of transparent flat plate samples with different thicknesses, can only carry out dispersion compensation on the measurement of a sample with a certain fixed thickness specification, and is not suitable for the dispersion compensation of the transparent flat plate samples with different thicknesses.

Disclosure of Invention

Aiming at the defects in the prior art, the technical problem to be solved by the invention is as follows: provides a dispersion compensation method and a measuring device suitable for short coherence Taman interferometry of transparent flat plate samples with different thicknesses.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows: a dispersion compensation method of short-coherence Taman interference is characterized in that a rotatable fine tuning compensation plate and a replaceable coarse tuning compensation plate are arranged in a short-coherence Taman interferometer, the size of an included angle between the normal direction of the fine tuning compensation plate and the optical axis of a located optical path is changed by rotating the fine tuning compensation plate, coarse tuning compensation plates with different thicknesses are replaced, the optical path difference of each wavelength between reference light and test light is zero, and dispersion compensation is carried out, wherein: the fine tuning compensation plate and the coarse tuning compensation plate have the same dispersion characteristic as the measured transparent flat plate sample.

Preferably, the fine tuning compensation plate is disposed in a reference optical path of the short coherence Taeman interferometer and the coarse tuning compensation plate is disposed in a reference optical path of the short coherence Taeman interferometer.

Preferably, the fine tuning compensation plate is disposed in a reference optical path of the short coherence Taeman interferometer and the coarse tuning compensation plate is disposed in a test optical path of the short coherence Taeman interferometer.

Preferably, the fine tuning compensation plate is disposed in a test optical path of the short coherence Taeman interferometer and the coarse tuning compensation plate is disposed in a reference optical path of the short coherence Taeman interferometer.

Preferably, the coarse adjustment compensation plate is a group of different thickness grading specification plates with the step difference of a mm, the maximum thickness variation amount which can be compensated by the fine adjustment compensation plate is b mm, and a should not be greater than b.

Correspondingly, the short coherence Taeman interference measuring device comprises a short coherence light source, a collimating mirror, a light splitting element, a first reference mirror, a second reference mirror, a condenser lens, an imaging lens, a camera, a rotatable fine adjustment compensation plate and a replaceable coarse adjustment compensation plate; the light emitted by the short coherent light source is converted into parallel light by a collimating mirror, the parallel light is divided into reference light and test light by a light splitting element, the reference light is transmitted by a fine adjustment compensating plate, is reflected by a first reference mirror, returns along the original path, is reflected to an imaging light path by the light splitting element, is transmitted by a measured transparent flat plate sample, is reflected by a second reference mirror, returns along the original path, is transmitted to the imaging light path by the light splitting element, forms interference with the reference light returned to the imaging light path, is imaged to a camera target surface by an imaging lens, changes the included angle between the normal direction and the optical axis of the light path by rotating the fine adjustment compensating plate and changes coarse adjustment compensating plates with different thicknesses, combines to realize that the optical path difference of each wavelength between the reference light and the test light is zero, performs dispersion fringe compensation, enables a camera to obtain a clear interference fringe image, and performs analysis and calculation on the interference image, measuring the transmitted wave aberration of the measured transparent flat plate sample, wherein: the fine tuning compensation plate and the coarse tuning compensation plate have the same dispersion characteristic as the measured transparent flat plate sample.

Preferably, the fine tuning compensation plate is disposed in a reference optical path of the short coherence Taeman interferometer and the coarse tuning compensation plate is disposed in a reference optical path of the short coherence Taeman interferometer.

Preferably, the fine tuning compensation plate is disposed in a reference optical path of the short coherence Taeman interferometer and the coarse tuning compensation plate is disposed in a test optical path of the short coherence Taeman interferometer.

Preferably, the fine tuning compensation plate is disposed in a test optical path of the short coherence Taeman interferometer and the coarse tuning compensation plate is disposed in a reference optical path of the short coherence Taeman interferometer.

Preferably, the coarse adjustment compensation plate is a group of different thickness grading specification plates with the step difference of a mm, the maximum thickness variation amount which can be compensated by the fine adjustment compensation plate is b mm, and a should not be larger than b.

Preferably, the beam splitting element is a beam splitting prism.

Preferably, the light splitting element is a combination of a light splitting plate and a light splitting plate compensation plate having the same dispersion characteristics as the light splitting plate.

The invention has the beneficial technical effects that: in the short coherence Taemann interferometer, a rotatable fine tuning compensation plate and a replaceable coarse tuning compensation plate are added, the size of an included angle between the normal direction of the fine tuning compensation plate and the optical axis of the optical path is changed by rotating the fine tuning compensation plate, and the coarse tuning compensation plates with different thicknesses are replaced, so that dispersion compensation can be realized when transparent flat plate samples with different thicknesses are measured, and the short coherence Taemann interferometer is more suitable for batch measurement.

Drawings

FIG. 1 is a schematic diagram of the optical structure of the short coherence Taeman interferometer principle;

FIG. 2 is a schematic diagram of an optical structure of a first embodiment of a dispersion compensation method and a measurement apparatus for short coherence Taman interference according to the present invention;

FIG. 3 is a schematic diagram of the optical path change of the fine tuning compensation plate in the first embodiment of the dispersion compensation method and the measurement device for short coherence Taman interference provided by the present invention;

FIG. 4 is a schematic diagram of a method for compensating dispersion of short coherence Taman interference and a method for compensating dispersion of short coherence Taman interferenceThe thickness variation amount which can be compensated by rotating the fine adjustment compensation plateIncluded angle between the normal direction of the fine adjustment compensation plate and the optical axis of the reference lightA relationship diagram of (1);

FIG. 5 is a schematic diagram of a dispersion compensation method and a measurement apparatus for short coherence Taman interference according to an embodiment of the present inventionWhen the maximum value is 70 degrees, the maximum thickness variation amount which can be compensated by rotating the fine adjustment compensation plateAnd its thicknessA relationship diagram of (1);

FIG. 6 is a schematic diagram of an optical structure of a second embodiment of the dispersion compensation method and measurement apparatus for short coherence Taman interference provided by the present invention;

FIG. 7 is a schematic diagram of an optical structure of a third embodiment of the dispersion compensation method and measurement apparatus for short coherence Taman interference provided by the present invention;

FIG. 8 is a schematic diagram of an optical structure of a fourth embodiment of the dispersion compensation method and measurement apparatus for short coherence Taman interference provided by the present invention;

in the figure: the device comprises a short coherent light source 1, a collimating mirror 2, a beam splitter prism 3, a first reference mirror 4, a second reference mirror 5, a condensing lens 6, an imaging lens 7, a camera 8, a measured transparent flat plate sample 9, a fine adjustment compensation plate 10, a coarse adjustment compensation plate 11, a beam splitter plate 12 and a beam splitter plate compensation plate 13.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments, but not all embodiments, of the present invention; all other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

For convenience of description, in all the embodiments described below, the refractive index of the compensation plate 10 is set to be fineThe propagation distance of the reference light or the test light at the time of single transmission in the fine adjustment compensation plate 10 isThe thickness of the fine adjustment compensation plate 10 isThe propagation distance of the reference light or the test light in the single transmission in the coarse adjustment compensation plate 11 isThe thickness of the coarse adjustment compensation plate 11 isThe distance of travel of the test light in a single transmission in the transparent flat plate sample 9 to be tested isThe thickness of the transparent flat plate sample 9 to be measured is。