EP4356083A1 - Vorrichtung zur messung der spektralen reflexion, insbesondere konkaver kugelspiegeloberflächen, und verfahren zur messung an dieser vorrichtung - Google Patents
Vorrichtung zur messung der spektralen reflexion, insbesondere konkaver kugelspiegeloberflächen, und verfahren zur messung an dieser vorrichtungInfo
- Publication number
- EP4356083A1 EP4356083A1 EP21945835.3A EP21945835A EP4356083A1 EP 4356083 A1 EP4356083 A1 EP 4356083A1 EP 21945835 A EP21945835 A EP 21945835A EP 4356083 A1 EP4356083 A1 EP 4356083A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- measurement
- integrating sphere
- photodetector
- spectral reflectance
- light source
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000005259 measurement Methods 0.000 title claims abstract description 46
- 230000003595 spectral effect Effects 0.000 title claims abstract description 36
- 238000000034 method Methods 0.000 title claims description 20
- 238000001514 detection method Methods 0.000 claims abstract description 21
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 14
- 238000005286 illumination Methods 0.000 claims abstract description 12
- 230000005855 radiation Effects 0.000 claims abstract description 6
- 238000011156 evaluation Methods 0.000 claims abstract description 4
- 239000013307 optical fiber Substances 0.000 claims description 5
- 230000003287 optical effect Effects 0.000 description 16
- 239000013074 reference sample Substances 0.000 description 7
- 238000002310 reflectometry Methods 0.000 description 6
- 238000000691 measurement method Methods 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 4
- 239000000523 sample Substances 0.000 description 3
- 238000013461 design Methods 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000004476 mid-IR spectroscopy Methods 0.000 description 1
- 108090000623 proteins and genes Proteins 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/55—Specular reflectivity
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/02—Details
- G01J3/0205—Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows
- G01J3/0229—Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows using masks, aperture plates, spatial light modulators or spatial filters, e.g. reflective filters
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/02—Details
- G01J3/0205—Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows
- G01J3/0254—Spectrometers, other than colorimeters, making use of an integrating sphere
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/28—Investigating the spectrum
- G01J3/42—Absorption spectrometry; Double beam spectrometry; Flicker spectrometry; Reflection spectrometry
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
- G01M11/005—Testing of reflective surfaces, e.g. mirrors
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/28—Investigating the spectrum
- G01J3/42—Absorption spectrometry; Double beam spectrometry; Flicker spectrometry; Reflection spectrometry
- G01J2003/425—Reflectance
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2201/00—Features of devices classified in G01N21/00
- G01N2201/06—Illumination; Optics
- G01N2201/065—Integrating spheres
Definitions
- the invention falls within the field of the measurement technique in optics, and is primarily intended for the production and inspection of optical mirror surfaces.
- the invention relates to a device for the measurement of spectral reflectance, in particular of concave spherical mirror surfaces, and the measurement method using this device.
- the measurement of optical parameters plays a crucial role in order to guarantee the quality and functionality of the resulting optical element.
- the measurement results are further used as feedback for the production process.
- One of the most important parameters of an optical element, especially mirrors, is its reflectance for given wavelengths of light. Reflectance is measured in principle by defining the spectral characteristic of the light incident on the element to be measured and the spectral characteristic of the light reflected from the element to be measured and determining the reflectance of the area from these quantities.
- the reflectance measurement methods differ in the determination of these two quantities. Reflectance can be measured for a single wavelength or for a specific spectral range.
- the reference sample to which the measured area is compared is mainly used to quantify the spectral reflectance of optical surfaces.
- This reference sample has two main drawbacks. With use, the sample wears out and thus changes its qualities, so it must be periodically remeasured in a certified laboratory. An example of this measurement is described in "Reflectometers for Absolute and Relative Reflectance Measurements in the Mid-IR Region at Vacuum, Jinhwa Gene, Sensors 2021, 21(4), 1169' “available at "https://doi.org/10.3390/s21041169”. In addition, methods with a fundamentally limited light beam size are used, where reflectance is measured in a limited area with a diameter on the order of millimetres.
- JP2002328103 INSTRUMENT AND METHOD FOR MEASURING REFLECTIVITY FOR DETERMINING REFLECTIVITY IN SELECTED MEASURING PORTION OF SPECTRUM-DEPENDENT REFLECTIVE MEASURING OBJECT
- JPH10148572A SPECTRAL REFLECTIVITY MEASUREMENT DEVICE
- JPH10239154A REFLECTIVITY METER
- a reference sample with a known spectral reflectance is used and this is compared with the spectral reflectance of the sample to be measured, where the area to be measured is very small and a narrow collimated beam of light is used for the measurement.
- JPH10111240A (APPARATUS FOR MEASURING SPECTRAL REFLECTANCE)
- JPH10111240A (APPARATUS FOR MEASURING SPECTRAL REFLECTANCE)
- a special optical system is used to measure the spectral reflectance at several points simultaneously by photographing the reflected spectrum with a CCD camera.
- the purpose of the presented invention is to introduce a new device and method for measuring the spectral reflectance of large concave spherical mirror surfaces that do not use a reference sample and measure the effective spectral reflectance of the entire element, i.e., the mirror surface, because for the practical use of optical elements we are primarily interested in the effective reflectance of its entire optical surface.
- the invention is a device for the measurement the spectral reflectance, in particular of concave spherical mirror surfaces, using a light source and a reference measurement, the essence of which consists of an interchangeable illumination block and a detection block, which are installed near the centre of curvature of the mirror surface to be measured, wherein both the illumination block comprises a light source and a beam reducer provided with a aperture and the detection block comprises a hollow integrating sphere, on which a photodetector is connected with a control and evaluation computer, and on the other hand, the integrating sphere is provided with an input port on a part of its surface, against which an affected area is defined on an opposite part of the inner surface of the integrating sphere for measuring the radiation characteristics of a light beam initiated in the light source and passing through the aperture of the beam reducer and the input port of the integrating sphere.
- the integrating sphere is connected to the photodetector by an optical fibre, wherein the photodetector comprises a spectrophotometer and the light source is broad spectrum.
- Another essence of the invention is a method for measuring spectral reflectance, in particular of concave spherical mirror surfaces, on a device according to claim 1 or 2, implemented in such a way that firstly, in a first stage, the spectral response of the incident light beam on the affected area of the integrating sphere of the detection block is measured independently by means of a photodetector and the result is recorded in a computer evaluation program.
- the functional members of the illumination block and the detection block are set so that the light beam illuminates only the mirror surface through the aperture of the reducer and the reflected light beam after reflection from the mirror surface is concentrated on the same affected area of the rear part of the inner surface of the integrating sphere and the photodetector measures the response of the reflected light beam in the detection block and the result is again recorded in the computer evaluation program.
- the computer evaluates the data from the reference and actual measurements and calculates the reflectance of the mirror surface, thus completing the measurement process.
- the invention achieves a new and higher effect in that it is possible to measure the reflectance of a concave mirror, and the entire surface at once.
- the principle of this method does not change even when measuring large mirror surfaces.
- the method used is absolute; there is no need to use a reference sample, which introduces an additional source of uncertainty into the measurement.
- Due to the use of an integrating sphere, the measurement method is not sensitive to the by the exact alignment of the assembly.
- An important part of the assembly is the beam reducer in the illuminating section, which ensures that the light beam illuminates only the mirror surface.
- the method uses the centre of curvature of a spherical mirror, which has the property that a ray of light coming from this point returns to this point after reflection from the spherical surface.
- fig .1 is a schematic of the device with the arrangement of its individual components in the reference measurement
- fig.2 is a diagram of the device with the arrangement of its individual components during the actual measurement of the reflectivity of the optical surface.
- the device for the measurement of the spectral reflectance of concave spherical mirror surfaces 1 comprises, in a basic embodiment, an illumination block 2 and a detection block 3, which are installed near the centre H of curvature of the measured mirror surface 1.
- the illumination block 2 comprises a light source 21 and a beam reducer 22.
- the detection block 3 comprises a hollow integrating sphere 31, which is connected by an optical fibre 32 to a photodetector 33 realized in the form of a spectrophotometer.
- the photodetector 33 is connected to the control and evaluation computer 4.
- the integrating sphere 31 is provided with an input port 311 on a portion of its surface, against which an affected area 312 is defined on an opposite portion of the inner surface of the integrating sphere 31 for measuring the radiation characteristics of a light beam 2 H initiated in the light source 21 and clipped by the aperture 221 of the beam reducer 22.
- the measurement method on the above described device is basically carried out in three steps and consists of a reference measurement, the actual measurement of the spectral characteristics of the light after reflection on the measured surface and the calculation of the spectral reflectance of the measured mirror surface 1.
- the illumination block 2 is installed so that the reducer 22 is positioned in front of the input port 311. of the integrating sphere 31 and only the affected area 312 of the inner surface of the integrating sphere 31 is illuminated from the light source 21 through the aperture 221 of the reducer 22 by the light beam 211.
- the functional members of the illumination block 2 and the detection block 3 are set according to FIG. 2 so that the light beam 211 illuminates only the mirror surface 1 through the aperture 221 of the reducer 22.
- the integrating sphere 31 is installed so that its input port 311 is oriented against the mirror surface 1, so that the reflected light beam 211_ is concentrated on the same affected area 312 after reflection from the mirror surface 1 the back of the inner surface of the integrating sphere 31 If this is satisfied, the photodetector 33 measures the spectral response of the reflected light beam 2L1 in the detection block 3 and the result is again recorded in the evaluation program in the computer 4.
- the data from the reference and the actual measurement are evaluated in computer 4 and the reflectance of mirror surface 1 is calculated. This completes the measurement process.
- the optical fibre 32 may be omitted and the photodetector 33 may be integrated directly on the integrating sphere
- a broad-spectrum light source 21 must be used that covers all of the desired wavelengths of light to be measured, then a photodetector 33 in the form of a spectrophotometer must be used. It is also possible to consider a version where only one wavelength of light is measured, then in the detection block 3 a photodetector 33 of the type e.g. photodiode or photomultiplier can be used, when this photodetector 33 must be sensitive for the given wavelength of the measured light.
- the measured mirror surface 1 does not have to be exactly spherical, the method allows to measure even mirrors with relatively large deviation from the ideal spherical shape. Different forms can be measured that allow point-to-point viewing, i.e., the measured area from a real object at a finite distance produces a real image at a finite distance.
- the spectral measurement setup for measuring concave spherical mirror surfaces according to the invention is intended in particular for measuring the absolute spectral reflectance of optical surfaces, which is the most important optical parameter of mirror optical components. It can therefore be used in post-production verification and certification of mirror surface quality as well as in routine quality and wear control of mirror surfaces.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/CZ2021/000026 WO2022262880A1 (en) | 2021-06-16 | 2021-06-16 | Device for the measurement of the spectral reflectance, in particular concave spherical mirror surfaces, and method of the measurement on this device |
Publications (1)
Publication Number | Publication Date |
---|---|
EP4356083A1 true EP4356083A1 (de) | 2024-04-24 |
Family
ID=84284021
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP21945835.3A Pending EP4356083A1 (de) | 2021-06-16 | 2021-06-16 | Vorrichtung zur messung der spektralen reflexion, insbesondere konkaver kugelspiegeloberflächen, und verfahren zur messung an dieser vorrichtung |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP4356083A1 (de) |
CZ (1) | CZ2022204A3 (de) |
WO (1) | WO2022262880A1 (de) |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006071510A (ja) * | 2004-09-02 | 2006-03-16 | Pentax Corp | 反射率測定方法及び反射率測定装置 |
JP5370409B2 (ja) * | 2011-05-18 | 2013-12-18 | 株式会社島津製作所 | 絶対反射測定装置 |
CN107132029B (zh) * | 2017-05-12 | 2020-09-22 | 电子科技大学 | 一种同时测量高反射/高透射光学元件的反射率、透过率、散射损耗和吸收损耗的方法 |
CN107037007A (zh) * | 2017-05-18 | 2017-08-11 | 北京奥博泰科技有限公司 | 一种带自动校准功能的玻璃反射比测量装置及方法 |
CN107884368B (zh) * | 2017-10-18 | 2020-12-04 | 湖南文理学院 | 一种光学测试***和测试方法 |
-
2021
- 2021-06-16 EP EP21945835.3A patent/EP4356083A1/de active Pending
- 2021-06-16 WO PCT/CZ2021/000026 patent/WO2022262880A1/en active Application Filing
- 2021-06-16 CZ CZ2022-204A patent/CZ2022204A3/cs unknown
Also Published As
Publication number | Publication date |
---|---|
CZ2022204A3 (cs) | 2022-12-07 |
WO2022262880A1 (en) | 2022-12-22 |
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Effective date: 20231113 |
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