CN113916124B - Fizeau interferometer with tubular reference illumination system and method for phase shifting technique of tubular reference illumination system - Google Patents
Fizeau interferometer with tubular reference illumination system and method for phase shifting technique of tubular reference illumination system Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B9/00—Measuring instruments characterised by the use of optical techniques
- G01B9/02—Interferometers
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
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Abstract
The invention relates to the field of interferometers, in particular to a Fizeau interferometer with a tubular reference lighting system and a method for using the tubular reference lighting system for phase shifting technology. The tubular reference lighting system comprises a first diaphragm, a first objective lens, a first silver-plated small flat crystal, a first tubular reference main body, a second silver-plated small flat crystal and a second objective lens, one end of the first tubular reference main body is glued or glued with the first silver-plated small flat crystal, the other end of the first tubular reference main body is glued or glued with the second silver-plated small flat crystal, the first diaphragm and the first objective lens are fixed on one side, connected with the first tubular reference main body and the first silver-plated small flat crystal, of the first tubular reference main body through a first support, the second objective lens is fixed on the other side of the first tubular reference main body through a second support, and the first diaphragm is located on the focal plane of the first objective lens.
Description
Technical Field
The invention relates to the field of interferometers, in particular to a Fizeau interferometer with a tubular reference illumination system and a method for using the tubular reference illumination system for phase shifting technology.
Background
The only purpose of the ancient Fizeau interferometer is to measure the flatness, which is the simplest optical instrument, and when in observation, the flatness is judged by taking the pupil of human eyes as a diaphragm and visually observing the concave-convex of interference fringes. The plane equal-thickness interferometer developed by China national institute of metrology Zhang Cheng in the last 60 th century is to add an observation small objective lens and a micrometer eyepiece into an ancient Fizeau interferometer, and the cross line of the observation eyepiece can be used for measuring the bending degree of an interference fringe of an open crystal. Thereby eliminating the bending amount of interference fringes estimated by visual inspection. And is produced in mass by Beijing metering instrument factories of the national metering administration. Meanwhile, some factories in China also produce similar plane interferometers with different calibers. There are also plane-equal-thickness interferometers using laser illumination.
The disadvantages of planar isopachous interferometers are: (1) The direction of interference fringes generated by the two flat crystals and the adjustment of the fringe width need manual operation, the operation is difficult, and (2) the standard flat crystals and the measured flat crystals are easy to be marked out. (3) The distance between two flat crystals participating in interference is nearly close to contact, and meanwhile, a good insulation box body is not provided, so that the measurement error caused by the influence of a temperature field is relatively large. (4) The flatness deviation of a certain point on the diameter of the micro-ocular is not easy to measure, and only the maximum flatness deviation of the cross section can be measured. Thus, high-precision flat crystals cannot be verified.
The disadvantages of the planar phase-shifting interferometer are: (1) The standard flat crystal verification result of the phase-shifting interferometer is calculated by three-face method mutual detection, and the three-face method can not separate the measurement result from the measurement error. The measurement result contains a large amount of measurement errors. The three-side method is not a good method, and four-side method mutual detection is adopted to separate measurement errors. (2) expensive: manufacturers monopolize markets to bring prices out of the range where cost performance is compatible, one imported phase-shifting planar interferometer costs millions of dollars, and even in the eighth and nineties of the last century, the price-shifting planar interferometer can be operated as a decoy for going out of the country. (3) Thousands of plane phase-shifting interferometers are imported at present and the problem of unified magnitude is already present. That is, the same flat crystal is detected on different phase-shifting interferometers, and the difference of detection results exceeds the allowable difference. (4) The phase-shifting interferometer can use a three-dimensional stereograph to represent the flatness deviation of a plane, and the method cannot be used for measuring the flatness with high precision because the standard flat crystal is not used for correcting the three-dimensional stereograph.
Disclosure of Invention
The invention aims to provide a Fizeau interferometer with a tubular reference lighting system and a method for using the tubular reference lighting system in a phase shifting technology, which solve the problem that the distance between two flat crystals involved in interference in the conventional plane equal-thickness interferometer is nearly close to contact, so that measurement errors caused by the influence of a temperature field are relatively large.
In order to solve the technical problems, the first technical scheme adopted by the invention is as follows:
the Fizeau interferometer with the tubular reference lighting system is characterized by comprising a Fizeau interferometer body and the tubular reference lighting system, wherein the tubular reference lighting system is arranged between a light source of the Fizeau interferometer body and a second diaphragm, and the light source is white light, a first interference filter or white light and monochromatic light. The tubular reference lighting system comprises a first diaphragm, a first objective lens, a first silver plating small flat crystal, a first tubular reference main body, a second silver plating small flat crystal and a second objective lens, wherein one end of the first tubular reference main body is glued or glued with the first silver plating small flat crystal, the other end of the first tubular reference main body is glued or glued with the second silver plating small flat crystal, the first diaphragm and the first objective lens are fixed on one side, connected with the first silver plating small flat crystal, of the first tubular reference main body through a first support, the second objective lens is fixed on the other side of the first tubular reference main body through a second support, the first diaphragm is positioned on the focal plane of the first objective lens, light emitted by the light source becomes divergent light after passing through the first diaphragm, the divergent light becomes parallel light after passing through the first silver plating small flat crystal, the first tubular reference main body and the second silver plating small flat crystal in sequence, convergent light is formed through the second objective lens, the convergent light enters the rope interferometer body after passing through the second diaphragm, and the second diaphragm is positioned on the focal plane of the second objective lens.
The further technical proposal is that a standard plat crystal and a checked plat crystal are arranged in the Fizeau interferometer body, the distance between the standard plat crystal and the checked plat crystal is L2, a first tubular shapeThe length of the reference main body is L 1 After passing through the optical path system in the Sophia interferometer body, the converging light irradiates the standard flat crystal and the checked flat crystal in sequence, and the optical path system comprises a CCD device.
The further technical scheme is that the side of the first tubular reference main body is provided with two M5 screw holes which are internally and externally penetrated, the two M5 screw holes are respectively detachably provided with a digital micro-manometer and an air pump, a standard flat crystal is fixed through a first mounting frame, and a detected flat crystal is fixed through a second mounting frame.
The further technical scheme is that the light source further comprises an LED lamp and a second interference filter, the tubular reference lighting system further comprises a turntable, a third silver plating small flat crystal, a second tubular reference main body and a fourth silver plating small flat crystal, and the Sophia interferometer body 1 comprises a second CCD device, a second reflector, an observation objective lens, a half reflector, a main lens, a main flat crystal, a gauge block, a working flat crystal and a workbench. The parallel light rays are emitted from the second silver plating small flat crystal, irradiated onto the third silver plating small flat crystal through the through hole of the rotary table, then sequentially pass through the third silver plating small flat crystal, the second tubular reference main body and the fourth silver plating small flat crystal, form converging light rays through the second objective, form second diverging light after passing through the second diaphragm, pass through the second reflector and the half reflector, and are projected onto the main lens, the second diverging light rays are changed into second parallel light from the main lens, the second parallel light rays reach the working flat crystal and the surface of the gauge block lapped on the working flat crystal through the interferometer main flat crystal, the gauge block is lapped on the working surface of the working flat crystal, and the gauge block is placed on the working table. When the distance L from the main plane crystal working surface of the interferometer to the working plane crystal working surface 6 And a first tubular reference dimension L 3 When equal, L 3 The dimensions equal to about 140mm are used for the assay 1 isotopy, only for comparative measurement L 3 Equal to 60mm, zero-order interference fringes appear on the surface of the working flat crystal, and the dimension L of the measured block 5 Dimension L with the second tubular reference body 4 Equally, zero-order interference fringes can also appear on the surface of the gauge block. The downward movement of the workbench is larger than 100mm, the working flat crystal is placed on the movable workbench with adjustable level, and the workbench is fixed on the interferometerOn the base, when the surface of the working flat crystal is perpendicular to the optical axis and parallel to the main flat crystal, the distance L between the surface of the working flat crystal and the main flat crystal 6 Dimension L with first tubular reference body 3 When the difference is smaller than the monochromatic light interference capability, an interference pattern appears on the surface of the working flat crystal, and the dimension L of the measured block 5 Dimension L with the second tubular reference body 4 Equally, interference patterns can also occur on the working surfaces of the gauge blocks. Adjusting the workbench to make the interference fringe parallel to the short side of the gauge block, simultaneously using white light and monochromatic light to illuminate, and adjusting the workbench to make L 6 And L is equal to 3 When the gap is smaller than 3 mu m, a group of white light zero-order interference fringes are overlapped on the monochromatic light interference fringes in the interference fields of the gauge block and the working flat crystal, the zero-order black fringes are adjusted to be in the center of the gauge block, if the zero-order fringes of the working flat crystal and the zero-order fringes when leaving are on the same straight line, the size of the two is equal, the size of the size difference of the two is determined according to the size of the zero-order fringes of the two, when the distance difference is increased, the zero-order fringes on the gauge block in the displacement direction of the interference fringes are in front, the gauge block is in +bias, and otherwise the gauge block is in-bias. The interference pattern on the surface of the interference field adopts monochromatic light for illumination, passes through the main lens, the half reflector and the observation objective lens, forms images near the focal plane of the observation objective lens, is provided with a second CCD device, receives the image information of the interference field, and transmits the interference pattern to a computer screen to give a verification result. If the gauge blocks which are lapped on the working flat crystal at the moment are two gauge blocks with the same size, removing the third silver plating small flat crystal, the second tubular reference body and the fourth silver plating small flat crystal. Because the two blocks have slightly different sizes, zero-order black stripes on the two blocks have a distance, one block is 1 equal block, the length size of the two blocks is known, the size of the other block is the number of stripes (containing symbols) of the distance multiplied by half wavelength of monochromatic light and the size correction quantity of the known block, the distance is measured by using the integer number of stripes determined by white light zero-order black stripes, the fractional part of the stripes is measured by using the monochromatic light, if the size of the block is the same as the size of a steel ball, the size of the steel ball can be detected, the three-wire size can be detected in the same way, the size difference of the blocks for detecting the standard gap of a knife edge ruler can be measured in the same way, and the three-wire size can be measured in the same way The second objective, fizeau interferometer diaphragm, second reflector, half reflector, observation objective, second CCD device, main lens and main crystal are all installed on the second support of interferometer, when the installation is regulated, the main optical axis exists in horizontal plane, the working table is a component whose up-down moving range is not less than 100mm to detect the gauge block with internal size of 100mm, and has grating component for displaying its position, its resolution can be displayed to micrometer, and displayed in computer screen, the working surface of working flat crystal can produce zero black stripe, and the working flat crystal can be different according to different uses by means of horizontal diameter of working flat crystal as zero position of grating. The measuring device is used for detecting the working flat crystal of which the gauge block is 1 and the working flat crystal of which the center is not coated with the film and the width is 10mm, and the working flat crystal used for comparison measurement is a common non-coated flat crystal. And the second tubular datum is used for detecting the 1-class gauge block, and is arranged in a counter bore of a through hole of a turntable of the interferometer and consists of a third silver-plated small flat crystal, a fourth silver-plated small flat crystal and a second tubular datum body. And the third silver plating small flat crystal and the fourth silver plating small flat crystal are respectively photo-glued on working surfaces at two ends of the second tubular reference main body. The parallelism of working surfaces at two ends of the second tubular reference body is less than 0.1 mu m, and the dimension L of the second tubular reference body 4 To achieve 1X 10 wavelength uncertainty -8 Is verified. When the adjusting workbench is at 0 position, interference fringes appear on the working surface of the working flat crystal, and zero-order black fringes are adjusted to be in the center of the working surface of the working flat crystal and parallel to the short side of the gauge block. When the dimension L of the gauge block 3 And a second tubular reference dimension L 4 When equal, zero black streaks appear in the center of the gauge block. The black stripe on the gauge block and the black stripe on the working flat crystal are on the same straight line, or the zero-order black stripe connecting line on the working flat crystal and the gauge block black stripe intersect at the center of the gauge block. Then the gauge block size L is indicated 5 Dimension L to a second tubular datum 4 Equal. The distance between the two zero-order black fringes indicates a difference in their dimensions, the integer fringe fraction of their difference is determined with the zero-order black fringes, and the fractional part of the interference fringe is measured with monochromatic light. The sum of stripes of the spacing multiplied by half wavelength of monochromatic light + the second tubular reference correction value and other correction values of 1 equivalent gauge are taken as the rulerCun.
The second technical scheme adopted by the invention is as follows:
a phase shifting technology adopts the Fizeau interferometer with the tubular reference illumination system to carry out phase shifting treatment.
The method comprises the following steps of S1, installing a standard flat crystal on a first installation frame, installing a checked flat crystal on a second installation frame, and arranging relevant scribing lines on the standard flat crystal, the checked flat crystal and the two installation frames, so that when the device is installed, the sections to be measured are aligned with each other; s2, the light source adopts white light and monochromatic light, and can illuminate simultaneously, when L 5 And L is equal to 4 When the difference between the two is smaller than the interference power of monochromatic light, a group of monochromatic interference fringes can be observed, and the L is gradually regulated by regulating support 5 Thus, the monochromatic light interference fringes are gradually darker and clearer, when L 5 And L is equal to 4 When the gap between the two interference fringes is smaller than 3 mu m, a group of white light interference fringes suddenly appear in a monochromatic light visual field, the white light zero-order interference fringes are adjusted to the center of the visual field, a monochromatic light source is turned off, the interference fringe direction is adjusted to be parallel to the direction of a detected section, the black zero-order interference fringes pass through the center diameter, meanwhile, the interference fringes are widened, the interference fringe width is adjusted to be extremely wide, a piece of color appears in the visual field to prepare for phase shifting treatment, white light is turned off, monochromatic light is turned on, and phase shifting photographing is carried out; s3, when the width of the interference fringe is adjusted to be extremely wide, the interference field is photographed for the first time through the CCD device, and the illumination Z of each point required is read 1i The air pressure in the reference main body is pressurized or depressurized through the air pump, the air pressure change in the tubular reference main body is measured through the digital micropressure meter, the micropressure meter is subjected to degree setting before the instrument is used, and the change amount of the digital micropressure meter when one interference fringe is changed is determined. Further changing the air pressure in the tubular reference main body by the air pump to change the refractive index of the air in the tubular reference main body, further increasing or reducing the wavelength of the optical path difference to be one fourth, calculating to be one eighth wavelength according to the length, taking a second photo at the moment, and reading the illumination Z of each point required by the photo 2i Sequentially increase or decreaseThe difference of the distance is reduced twice, each time the difference of the distance is increased or reduced by a quarter wavelength, and the illumination Z of each point is read 3i And Z 4i By means ofCalculating to obtain tan theta i A value; wherein: z is Z 1i ＝A i +Biconθ i ，Z 2i ＝A i +Bicon(θ i +90°)，Z 3i ＝A i +B i con(θ i +180°)，Z 4 i＝A i +B i con(θ i +270°), and Z 1 i、Z 2 i、Z 3i 、Z 4i The illumination of the photo at the point i is a fourth-order difference and a is a quarter wavelength difference i B is the background illuminance at point i i For maximum illumination of interference fringes at point i, the interference phase angle of the photo at point i is θ i Measured in degrees. S4, the sum of the planeness of the i points of the two flat crystals is P i ，P i ＝θ i Lambda/720, where P i And lambda is in μm.
In a further technical scheme, when the Fizeau interferometer body is a vertical interferometer, three standard flat crystals are sequentially detected according to steps S1-S4 by using a uniform supporting mode for the three standard flat crystals, the flatness deviation of the standard flat crystals is corrected, and then the average value of three measurement and detection is taken as the final result of the flatness deviation of the standard flat crystals. When the number of the reference flat crystals is two, each reference flat crystal is sequentially detected according to the steps S1-S4, each reference flat crystal needs to be detected twice, and the first time is that each point of the X-axis section of the reference flat crystal is aligned with each point of the X-axis section of the reference flat crystal, and the reference flat crystal is used for X i ,y i The flatness deviation of the point is corrected to obtain the standard flat crystal x to be detected i ,-y i The flatness deviation of the points, the second time is that the reference flat crystal is rotated 180 degrees, the points of the Y-axis cross sections of the standard flat crystal and the reference flat crystal are aligned, and the reference flat crystal is used for x i ,y i The flatness deviation of the point is corrected to obtain the standard flat crystal-x to be detected i ,y i The flatness deviation of the point is taken as the average value of four times of verification resultsThe end result of the deviation.
When the Fizeau interferometer body is a horizontal interferometer, four reference flat crystals can be obtained through four flat crystal mutual inspection of flat crystals carried by the interferometer. And the standard flat crystal is set to be flat crystal D, the reference flat crystal comprises flat crystal A, flat crystal B and flat crystal C, and relevant scribing lines are arranged on the flat crystal A, the flat crystal B, the flat crystal C, the flat crystal D and the two mounting frames, so that the sections to be measured are aligned with each other during the mounting. And mutually detecting flatness deviations of the flat crystal D and the other three flat crystals by a four-side method, wherein the steps are as follows, K1, placing the flat crystal B on a first bracket, placing the flat crystal A on a second bracket, aligning coordinates of each point on the Y-axis cross section of the flat crystal A and the Y-axis cross section of the flat crystal B one by one, and aligning each point on the AX axis of the flat crystal A and the X axis cross section direction of the flat crystal B one by using 0 point of the X coordinates to be symmetrical. And the X-axis cross section of the flat crystal A and the X-axis cross section of the flat crystal B are aligned with the coordinates of the four endpoints of the Y-axis cross section, the interference field is adjusted to a measurement state, and the sum of flatness deviation of the flat crystal A and the flat crystal B of each point of the X-axis cross section and the Y-axis cross section is measured. The surfaces of the flat crystals A and B are provided with ideal planes, the ideal planes are arranged to pass through two end points of the Y-axis section and are parallel to the two end points of the X-axis section, when the two ideal planes of the flat crystals coincide, the mathematical relational expression of Pz1=B0, y+A0, Y when the two ideal planes of the Y-axis section points on the flat crystals A and B coincide, and the mathematical relational expression of the sum of the planeness of the X-axis section points is Ps 1=Bx, 0+A-X,0; k2, taking down the flat crystal B, replacing the flat crystal C, aligning coordinates of each point on the Y-axis section of the flat crystal A and the flat crystal C one by one, and measuring in the same way as the step K1, wherein the mathematical relation of the sum of the planeness of each point on the Y-axis section of the flat crystal A and the flat crystal C is P z2 ＝C 0,y +A 0,y And the mathematical relation of the sum of the flatness of each point of the X-axis cross section is P s2 ＝C x,0 +A -x,0 The method comprises the steps of carrying out a first treatment on the surface of the K3, taking down the flat crystal A, replacing the flat crystal B, aligning coordinates of each point on the Y-axis section on the flat crystal C and the flat crystal B one by one, and measuring in the same way as the step K1, wherein the mathematical relation of the sum of the planeness of each point on the Y-axis section on the flat crystal A and the flat crystal B is P z4 ＝C 0,y +B 0,y The flatness of each point of the X-axis cross section is measured by turning the flat crystal B by 180 DEGAnd obtaining the mathematical relation of the sum of the planeness of each point of the X-axis section as P s4 ＝C x,0 +B x,0 The method comprises the steps of carrying out a first treatment on the surface of the K4, taking down the flat crystal C, replacing the flat crystal D, aligning coordinates of each point on the X-axis cross section of the flat crystal B and the flat crystal D one by one, and measuring in the same way as the step K1, wherein the mathematical relation of the sum of the planeness of each point on the X-axis cross section of the flat crystal C and the flat crystal D is P s5 ＝D x,0 +B x,0 Turning the flat crystal B into 180 degrees, measuring the sum of the planeness of each point of the Y-axis cross section, and obtaining the mathematical relation of the sum of the planeness of each point of the Y-axis cross section as P z5 ＝D 0,y +B 0,y The method comprises the steps of carrying out a first treatment on the surface of the K5, taking down the flat crystal B, replacing the flat crystal C, aligning coordinates of each point on the Y-axis section of the flat crystal D and the flat crystal C one by one, and measuring in the same way as the step K1, wherein the mathematical relation formula of the sum of the planeness of each point on the Y-axis section of the flat crystal D and the flat crystal C is P z6 ＝D 0,y +C 0,y The flat crystal C is turned to 180 degrees, the sum of the planeness of each point of the X-axis cross section is measured, and the mathematical relation of the sum of the planeness of each point of the X-axis cross section is obtained as P s6 ＝D x,0 +C x,0 The method comprises the steps of carrying out a first treatment on the surface of the K6, taking down the flat crystal C, replacing the flat crystal A, aligning coordinates of each point on the Y-axis section of the flat crystal D and the flat crystal A one by one, and measuring in the same way as the step K1, wherein the mathematical relation formula of the sum of the planeness of each point on the X-axis section is P s3 ＝D x,0 +A -x,0 The mathematical relation of the sum of the planeness of each point of the Y-axis section is P z3 ＝D 0,y +A 0,y The method comprises the steps of carrying out a first treatment on the surface of the And K7, calculating the planeness of each point X on the X-axis cross sections of the flat crystals B, C and D, and calculating the planeness of each point X on the X-axis cross sections of the flat crystals A, and calculating the planeness of each point X on the X-axis cross sections of the flat crystals B, C and D. Substituting the sum of the planeness of Y-axis sections of flat crystal A, flat crystal B, flat crystal C and flat crystal D into P z1 ＝B 0,y +A 0,y ，P z2 ＝C 0,y +A 0,y ，P z4 ＝C 0,y +B 0,y ，P z5 ＝D 0,y +B 0,y ，P z6 ＝D 0,y +C 0,y ，P z3 ＝D 0,y +A 0,y Can be used forTo obtain formula A 0,y ＝[2(P z1 +P z2 +P z3 )-((P z4 +P z5 +P z6 )]/6，B 0,y ＝[2(P z1 +P z4 +P z5 )-((P z2 +P z3 +P z6 )]/6，C 0,y ＝[2(P z2 +P z4 +P z6 )-((P z1 +P z3 +P z5 )]/6，D 0,y ＝[2(P z3 +P z5 +P z6 )-((P z1 +P z2 +P z4 )]And/6, obtaining flatness deviation of each point of Y-axis cross sections of the flat crystals A, B, C and D after solving, and substituting the sum of the flatness of each point of X-axis cross sections of the flat crystals A, B, C and D into P s1 ＝B x,0 +A -x,0 ，P s2 ＝C x,0 +A -x,0 ，P s4 ＝C x,0 +B x,0 ，P s5 ＝D x,0 +B x,0 ，P s6 ＝D x,0 +C x,0 ，P s3 ＝D x,0 +A -x,0 The formula A can be obtained -x,0 ＝[2(P s1 +P s2 +P s3 )-((P s4 +P s5 +P s6 )]/6，B x,0 ＝[2(P s1 +P s4 +P s5 )-((P s2 +P s3 +P s6 )]/6，C x,0 ＝[2(P s2 +P s4 +P s6 )-((P s1 +P s3 +P s5 )]/6，D x,0 ＝[2(P s3 +P s5 +P s6 )-((P s1 +P s2 +P s4 )]And (6) calculating the flatness deviation of each point of the X-axis cross sections of the flat crystals A, B, C and D.
Compared with the prior art, the invention has the beneficial effects that: by arranging the tubular reference illumination system, the light path conditions in the traditional plane equal-thickness interferometer and the phase-shifting interferometer are changed, interference fringes can be seen under the condition that two flat crystals are separated under the illumination of white light and general monochromatic light, so that the problem that the distance between the two flat crystals participating in interference in the conventional interferometer is almost close to contact, the measurement error caused by the influence of a temperature field is relatively large, and the phenomenon that a standard flat crystal and a measured flat crystal are easily marked out of a channel is avoided. Meanwhile, the light source replaces the previous laser light source, and the interferometer for flatness measurement is changed into the flatness interferometer with highest measurement precision, highest performance and cheapest price. The planar phase-shifting interferometer which is expensive nowadays is completely replaced. The application of the interferometer is further expanded to the field of the Michelson interferometer with high price for length measurement, and the application of the interferometer can be expanded to a new measurement field. The method can be used for measuring the flatness, measuring the center length of the gauge block with various dimensions such as 1 and the like and below, automatically measuring the center length of the gauge block, measuring the diameter of the steel ball and the three-wire non-force measuring device, measuring the thickness of a thin film and the thickness of a coating, verifying the standard gap gauge block size difference of a knife edge ruler, and the interferometer can be used for various precise measurements, the interferometer roundness measuring device can be used for measuring precise roundness and the like.
Drawings
FIG. 1 is a schematic diagram of a tubular reference illumination system of a Fizeau interferometer having a tubular reference illumination system according to the invention.
FIG. 2 is a schematic view of a vertical plane interferometer of the Fizeau interferometer with a tubular reference illumination system according to the invention.
FIG. 3 is a schematic diagram showing the serial number arrangement of the cross sections of two flat crystals in the test when the cross section of the X-axis diameter is the 1 st cross section.
FIG. 4 is a schematic diagram of a horizontal plane interferometer of a Fizeau interferometer with a tubular reference illumination system according to the invention.
FIG. 5 is a schematic representation of the position of the planar interferometer of the present invention in the ABCD area for determining the planarity of any point in the area.
FIG. 6 is a schematic illustration of a Fizeau interferometer assay 1 equivalent block with a tubular fiducial illumination system of the present invention.
Icon: 1-Fizeau interferometer body, 101-divergent light, 102-parallel light, 103-convergent light, 110-first interference filter, 200-white light source, 201-first diaphragm, 202-first objective, 203-first silvered small-level crystal, 204-first tubular reference body, 205-second silvered small-level crystal, 206-second objective, 207-second diaphragm, 301-1 st mirror, 302-2 nd mirror, 303-3 rd mirror, 304-4 th mirror, 305-first half mirror, 306-observation small objective, 307-first CCD device, 308-thermal cover, 309-main lens, 310-standard level crystal, 311-standard level crystal mount, 312-video and operating panel, 313-thermal cover door, 314-inspected flat crystal or reference flat crystal, 315-uniform bearing support layer, 316-positioning ring, 317-uniform bearing mounting frame, 318-workbench, 319-adjusting support, 401-sliding door, 402-first flat crystal, 403-horizontal interferometer first support frame, 404-second flat crystal, 405-horizontal interferometer second support frame, 406-large lens, 407-white light source, 408-interference filter, 409-diaphragm of tubular reference light source, 413-incubator, 414-fifth reflector, 415-fourth diaphragm, 416-third CCD device, 417-instrument workbench, 418-instrument adjusting support, 419-instrument bottom plate, 420-third half reflector, 421-imaging objective, 601-LED lamp, 602-second interference filter, 608-turntable, 609-operating table, 611-third silvered small flat crystal, 612-second tubular reference body, 613-fourth silvered small flat crystal, 616-interferometer mirror, 617-thermal cover (assembly), 618-second CCD device, 619-imaging objective, 620-second half mirror, 621-interferometer main lens, 622-main flat crystal, 623-gauge block, 624-working flat crystal, 625-interferometer base.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
Examples:
example 1
A Fizeau interferometer with a tubular reference illumination system comprises a Fizeau interferometer body 1 and the tubular reference illumination system, wherein the tubular reference illumination system is arranged between a light source 200 and a second diaphragm 207 of the Fizeau interferometer body 1, and the light source 200 is white light + a first interference filter 110 or white light + monochromatic light. The tubular reference lighting system comprises a first diaphragm 201, a first objective 202, a first silver plating small flat crystal 203, a first tubular reference main body 204, a second silver plating small flat crystal 205 and a second objective 206, wherein one end of the first tubular reference main body 204 is in optical cement or cementing with the first silver plating small flat crystal 203, the other end of the first tubular reference main body 204 is in optical cement or cementing with the second silver plating small flat crystal 205, the first diaphragm 201 and the first objective 202 are fixed on one side, which is connected with the first silver plating small flat crystal 203, of the first tubular reference main body 204 through a first bracket, the second objective 206 is fixed on the other side of the first tubular reference main body 204 through a second bracket, the first diaphragm 201 is positioned on the focal plane of the first objective 202, light rays emitted by the light source 200 become divergent lights 101 after passing through the first diaphragm 201, the parallel lights 102 are sequentially passed through the first silver plating small flat crystal 203, the first tubular reference main body 204 and the second silver plating small flat crystal 205, then form convergent lights 103 through the second objective 206, the convergent lights 103 enter the inside the cable body 207, and the second objective 206 are positioned on the focal plane of the second objective 206.
The Fidelity interferometer body 1 is internally provided with a standard flat crystal and a checked flat crystal, the distance between the standard flat crystal and the checked flat crystal is L2, the length of the first tubular reference main body 204 is L1, the converging light 103 sequentially irradiates the standard flat crystal and the checked flat crystal after passing through an optical path system in the Fidelity interferometer body 1, and the optical path system comprises a CCD device 307.
The side of first tubulose benchmark main part 204 is provided with two inside and outside penetrating M5 screw, and two M5 screw detachably install digital micropressure meter and air pump respectively, and standard plat form is fixed through first mounting bracket, and the plat form of being examined is fixed through the second mounting bracket.
Figure 2 shows a proprietary vertical plane interferometer. Light is emitted from the Fizeau interferometer body diaphragm 207, passes through mirrors 303, 304 and first half mirror 305 to the large lens 309 to become collimated light. Projected onto a standard flat crystal 310, which is mounted in a first mounting frame 311. Part of the light is reflected back to the large lens 305 by the standard plano-crystalline work surface and the other part continues to impinge on the work surface of the inspected plano-crystalline or reference plano-crystalline 314 and is reflected back to the large lens 309. The inspected flat or reference flat 314 is mounted on a second mount 317. The second mounting frame 317 is placed on a work table 318. From standard flat 310 and inspected flat or base, respectively The two coherent lights returned from the working surface of the quasi-flat crystal 314 pass through the half mirror 305 and the imaging objective 306, are imaged on the imaging surface of the imaging objective, and receive interference pattern information for the first CCD device 307 placed therein. The interference pattern is transmitted onto the interferometer screen 312. Two coherent light beams are reflected by the two plano-crystalline work surfaces, the path of light reflected by the standard plano-crystalline work surface is twice the distance L between the two plano-crystalline work surfaces less than the path of light reflected by the inspected plano-crystalline work surface 5 It is necessary to compensate for the multiple reflections within the tubular fiducial 204, the tubular fiducial 204 having a dimension L 4 . The interference fringes are clearer, white light illumination is increased, and when the difference between the interference fringes and the white light illumination is smaller than 3 mu m, a group of white light interference fringes are overlapped on the monochromatic light interference fringes. The interference fringes are further adjusted to carry out the above-mentioned verification of various values of the flat crystals. Including standard flat 310 with three reference flat verification instruments, the verification result may be dual-section flatness or multi-section flatness. The assay results are stored in the interferometer. Correction may be performed in the verification of the inspected flat 314. When the interferometer uses a three-dimensional stereographic map of the flatness deviation to represent a finer plane, the flatness deviation of the standard flat crystal should be corrected in the measurement results. Correction values for some measurement points can be added appropriately if necessary. Since the two flat crystals are supported in different ways, the influence of the dead weight deformation of the inspected flat crystal or the reference flat crystal 314 must be eliminated. A uniform supporting layer 315 is added on the supporting surface of the uniform supporting frame 317, and the uniform supporting layer 315 is a layer of fine powder or a layer of foam plastic or other fabrics, so as to realize uniform supporting of the flat crystals 314. The reference flat 314 is thus free from bending deformation and can be used directly for its verification results on a horizontal interferometer. The verification of standard flat 310 is its flatness deviation + its installed dead weight deformation. And similarly, the verification result of the checked flat crystal has no influence of the self-weight deformation. In order to ensure the measurement accuracy of the interferometer, the measurement coordinates of the first CCD device 307, the standard flat crystal 310 and the reference flat crystal or the detected flat crystal should be ensured to be unified, the error of the measurement coordinates should not exceed +/-0.2 mm, and the coaxiality of the first CCD device 307, the interferometer big lens 309, the standard flat crystal 310 and the detected flat crystal or the reference flat crystal 314 should be ensured firstly, and the first CCD device 307 and the big lens should be ensured The mirrors 309 are mounted on the same frame, their coaxiality is ensured by machining, and the mounting holes of the mounting bracket of the large lens 309 should be concentric with the outer circle thereof. The two mounting holes of the standard flat crystal mounting bracket 311 and the outer circles thereof should be concentric. The counter bore of the workbench 318 for placing the uniform supporting mounting frame 317 is concentric with the standard flat crystal mounting bracket 311 by a special tool, and the outer circle of the uniform supporting mounting frame 317 is concentric with the positioning hole thereof. To help align the same cross-section of the two flat crystals with each other. And the two flat crystals and the two supports are engraved with scribing lines, so that alignment is facilitated. To ensure a stable temperature during measurement, the interferometer is provided with a thermal cover 308, in front of which a thermal door 313 is arranged. To ensure measurement accuracy, the interferometer should be placed on a vibration-proof table. The room in which the interferometer is placed should meet the requirements of the flat crystal certification protocol.
FIG. six is a patent Fizeau interferometer measuring 1 equivalent gauge. The light source 200 further comprises an LED lamp 601 and a second interference filter 602, the tubular reference lighting system further comprises a turntable 608, a third silver-plated small plat form 611, a second tubular reference body 612, a fourth silver-plated small plat form 613, and the sorfie interferometer body 1 comprises a second CCD device 618, a second mirror 616, an observation objective 619, a half mirror 620, a main lens 621, a main plat form 622, a gauge block 623, a working plat form 624, and a working stage 609. After the parallel light 102 is emitted from the second silver plating small flat crystal 205, the parallel light irradiates onto the third silver plating small flat crystal 611 through a through hole of the turntable 608, then the parallel light 102 sequentially passes through the third silver plating small flat crystal 611, the second tubular reference main body 612 and the fourth silver plating small flat crystal 613, the converging light 103 is formed through the second objective lens 206, the converging light 103 passes through the second diaphragm 207 to form second diverging light, the second diverging light passes through the second reflector 616 and the half reflector 620 to be projected onto the main lens 621, the second diverging light comes out of the main lens 621 to become second parallel light, the second parallel light passes through the interferometer main flat crystal 622 to reach the working flat 624 and the surface of the gauge block 623 which is lapped on the working flat 624, and the working flat 624 is placed on the working table 609. When the distance L from the working surface of the main crystal 622 to the working surface of the working crystal 624 of the interferometer 6 With the firstTubular reference dimension L 3 When equal (L) 3 The dimensions equal to about 140mm are used for the assay 1 isotopy, only for comparative measurement L 3 Equal to 60 mm), zero-order interference fringes appear on the surface of the working flat crystal 624, and the dimension L of the measured block 623 5 Dimension L with second tubular reference body 612 4 Equally, zero-order interference fringes appear on the surface of the gauge block 623, at this time, the downward movement amount of the working stage 609 is greater than 100mm, the working flat crystal 624 is placed on the movable and adjustable horizontal working stage 609, the working stage 609 is fixed on the base 624 of the interferometer, when the surface of the working flat crystal 624 is perpendicular to the optical axis, i.e. parallel to the main flat crystal 622, and the distance L between the surface of the working flat crystal 624 and the main flat crystal 622 6 Dimension L to first tubular reference body 204 3 When the difference is smaller than the monochromatic light interference capability, an interference pattern appears on the surface of the working flat crystal 624, and the dimension L of the measured block 623 5 Dimension L with second tubular reference body 612 4 Equally, interference patterns will also appear on the working surface of the gauge block 623, the stage 609 is adjusted so that the interference fringes are parallel to the short sides of the gauge block 623, while white light and monochromatic light are used for illumination, and the stage 609 is adjusted so that L 6 And L is equal to 3 When the difference is smaller than 3 μm, a group of white light zero-order interference fringes appear in interference fields of the gauge block 623 and the working flat 624, the zero-order black fringes are overlapped on the center of the gauge block 623, if the zero-order fringes of the working flat 624 are on the same straight line with the zero-order fringes when leaving, the size of the difference between the two sizes is determined according to the size of the zero-order fringes, when the difference is increased, the zero-order fringes on the gauge block in the displacement direction of the interference fringes are in front, the gauge block is +biased, otherwise, the gauge block is-biased, the interference patterns on the surface of the interference field adopt monochromatic light illumination, the primary lens 621, the half mirror 620 and the observation objective 619 are adopted, the image is formed near the focal plane of the observation objective 619, a second CCD device 618 is arranged at the place, the interference patterns are transmitted to a computer screen, the verification result is given, if the gauge block 623 with the same size is ground on the working flat 624, the third small gauge block 611, the second tubular main body 611 and the second tubular standard 6 can be removed 12 and a fourth silver-plated small flat crystal 613, wherein the size of the two gauge blocks 623 is slightly different, zero-order black stripes on the two gauge blocks 623 have a space, one gauge block is 1 equal gauge block, the length size of the gauge block is known, the size of the other gauge block is the stripe number (containing symbols) of the space multiplied by half wavelength of monochromatic light+the known gauge block size correction amount, the space is measured by using the integer stripe number determined by white light zero-order black stripes, the fractional part of the stripe is measured by using the monochromatic light, if the size of the gauge block 623 is the same as the size of a steel ball, the size of the steel ball can be detected, the three-wire size can be detected similarly, the gauge block size difference of a standard gap of a detection knife edge ruler can be measured similarly, and the plating layer or coating thickness on the flat crystal can be measured. The second objective 206, the second diaphragm 207, the second mirror 616, the half mirror 620, the observation objective 619, the second CCD device 618, and the main lens 621 and the main crystal 622 are mounted on the second mount of the interferometer, and when the mounting is adjusted, the main optical axis exists in the horizontal plane, the stage 609 is a component whose up-down movement range is not less than 100mm to detect a gauge block of an inner dimension of 100mm, and has a grating part displaying its position, the resolution of which can be displayed to micrometers, and displayed in a computer screen, the working face of the working crystal 624 is made to be zero-order black streak, and the working crystal 624 varies according to the use by the horizontal diameter of the working crystal 624 as the zero position of the grating, the working flat crystal 624 for detecting the 1-class gauge block has a steel flat crystal and a working flat crystal with a center non-coating film width of 10mm, the working flat crystal 624 for comparing and measuring is a common non-coating film flat crystal, the working flat crystal is used for detecting the 1-class gauge block, a second tubular reference 612 is placed in a counter bore of a through hole of a turntable 608 of the interferometer, the second tubular reference 612 consists of a third silver plating small flat crystal 611, a fourth silver plating small flat crystal 613 and a second tubular reference main body 612, the third silver plating small flat crystal 611 and the fourth silver plating small flat crystal 613 are respectively optical glued on working surfaces at two ends of the second tubular reference main body 612, the parallelism of working surfaces at two ends of the second tubular reference main body 612 is less than 0.1 mu m, and the dimension L of the second tubular reference main body 612 4 To achieve 1X 10 wavelength uncertainty -8 When the light source of the work table is adjusted to be at the 0 position, interference fringes appear on the working surface of the work flat crystal 624, and zero-order black fringes are adjusted to be in the working surface of the work flat crystal 624Center, and short sides of the gauge block are parallel, equivalent to dimension L of gauge block 623 3 And a second tubular reference dimension L 4 When the zero-order black stripes appear in the center of the gauge block 623, the black stripes on the gauge block 623 and the black stripes on the working flat 624 are on the same straight line, or the zero-order black stripe connecting line on the working flat 624 and the gauge block 623 black stripes intersect at the center of the gauge block 623, then the size L of the gauge block 623 is indicated 5 Dimension L to second tubular datum 612 4 Equal, the distance between the two zero-order black fringes indicates that there is a difference between their dimensions, the integer fringe fraction of their difference is determined with the zero-order black fringes, the fractional part of the interference fringes is measured with monochromatic light, the total number of fringes (with symbols) of the pitch times the half wavelength of the monochromatic light + the correction value of the second tubular reference 612 and the other correction values of the 1-etc. gauge are of their dimensions.
Example 2.
A phase shifting technique uses the Fizeau interferometer with a tubular reference illumination system of example 1 for phase shifting.
The specific steps of detecting the planeness of the standard flat crystal and the detected flat crystal are as follows, S1, the standard flat crystal is installed on a first installation frame, the detected flat crystal is installed on a second installation frame, relevant scribing lines are arranged on the standard flat crystal, the detected flat crystal and the two installation frames, and when the installation is convenient, the sections to be measured are aligned with each other; s2, the light source 200 adopts white light and monochromatic light to illuminate simultaneously, when L 5 And L is equal to 4 When the difference between the two is smaller than the interference power of monochromatic light, a set of monochromatic interference fringes can be observed, and L is gradually adjusted by the adjusting support 319 5 Thus, the monochromatic light interference fringes are gradually darker and clearer, when L 5 And L is equal to 4 When the gap between the two interference fringes is smaller than 3 mu m, a group of white light interference fringes suddenly appear in a monochromatic light visual field, the white light interference fringes are adjusted to the center of the visual field, a monochromatic light source is turned off, the directions of the interference fringes are adjusted to be parallel to the directions of the detected sections, the black zero interference fringes pass through the center diameter, meanwhile, the interference fringes are adjusted to be extremely wide, a piece of color appears in the visual field to prepare for phase shifting treatment, white light is turned off, monochromatic light is turned on, and phase shifting photographing is carried out; s3, when the width of the interference fringe is adjusted to be extremely wide,taking a first picture of the interference field by means of the CCD device 307 and reading the illumination Z of the desired points 1i The air pressure in the reference main body is pressurized or depressurized through the air pump, the air pressure change in the tubular reference main body is measured through the digital micropressure meter, the micropressure meter is subjected to degree setting before the instrument is used, and the change amount of the digital micropressure meter when one interference fringe is changed is determined. Further changing the air pressure in the tubular reference main body by the air pump to change the refractive index of the air in the tubular reference main body, further increasing or reducing the wavelength of the optical path difference to be one fourth, calculating to be one eighth wavelength according to the length, taking a second photo at the moment, and reading the illumination Z of each point required by the photo 2i Sequentially increasing or decreasing the path difference twice, increasing or decreasing the path difference by one quarter wavelength each time, and reading the illumination Z of each point 3i And Z 4i By means ofCalculating to obtain tan theta i A value; wherein: z is Z 1i ＝A i +Biconθ i ，Z 2i ＝A i +Bicon(θ i +90°)，Z 3i ＝A i +B i con(θ i +180°)，Z 4 i＝A i +B i con(θ i +270°), and Z 1 i、Z 2 i、Z 3i 、Z 4i The illumination of the photo at the point i is a fourth-order difference and a is a quarter wavelength difference i B is the background illuminance at point i i For maximum illumination of interference fringes at point i, the interference phase angle of the photo at point i is θ i Measured in degrees. S4, the sum of the planeness of the i points of the two flat crystals is P i ，P i ＝θ i Lambda/720, where P i And lambda is in μm.
When the Fizeau interferometer body 1 is a vertical interferometer, the reference flat crystals cannot be generated by mutual inspection due to different supporting modes of the upper flat crystal and the lower flat crystal and different dead weights and deformation. It can only adopt three standard flat crystals to test the standard flat crystals of the instrument in sequence according to the steps S1-S4 in a uniform supporting mode, correct the flatness deviation of the standard flat crystals, and then take the average value of three measurement tests as the standardThe end result of the flatness deviation of the quasi-flat crystals. When the number of the reference flat crystals is two, each reference flat crystal is sequentially detected according to the steps S1-S4, each reference flat crystal needs to be detected twice, and the first time is that each point of the X-axis section of the reference flat crystal is aligned with each point of the X-axis section of the reference flat crystal, and the reference flat crystal is used for X i ,y i The flatness deviation of the point is corrected to obtain the standard flat crystal x to be detected i ,-y i The flatness deviation of the points, the second time is that the reference flat crystal is rotated 180 degrees, the points of the Y-axis cross sections of the standard flat crystal and the reference flat crystal are aligned, and the reference flat crystal is used for x i ,y i The flatness deviation of the point is corrected to obtain the standard flat crystal-x to be detected i ,y i And taking the average value of four verification results as the final result of the standard flat crystal flatness deviation.
When the Fizeau interferometer body 1 is a horizontal interferometer, four reference flat crystals can be obtained by four flat crystal mutual inspection of flat crystals carried by the interferometer. And the standard flat crystal is set to be flat crystal D, the reference flat crystal comprises flat crystal A, flat crystal B and flat crystal C, and relevant scribing lines are arranged on the flat crystal A, the flat crystal B, the flat crystal C, the flat crystal D and the two mounting frames, so that the sections to be measured are aligned with each other during the mounting. And mutually detecting flatness deviations of the flat crystal D and the other three flat crystals by a four-side method, wherein the steps are as follows, K1, placing the flat crystal B on a first bracket, placing the flat crystal A on a second bracket, aligning coordinates of each point on the Y-axis cross section of the flat crystal A and the Y-axis cross section of the flat crystal B one by one, and aligning each point on the AX axis of the flat crystal A and the X axis cross section direction of the flat crystal B one by using 0 point of the X coordinates to be symmetrical. And the X-axis cross section of the flat crystal A and the X-axis cross section of the flat crystal B are aligned with the coordinates of the four endpoints of the Y-axis cross section, the interference field is adjusted to a measurement state, and the sum of flatness deviation of the flat crystal A and the flat crystal B of each point of the X-axis cross section and the Y-axis cross section is measured. The surfaces of the flat crystals A and B are provided with ideal planes, the ideal planes are arranged to pass through two end points of the Y-axis section and are parallel to two end points of the X-axis section, when the two ideal planes of the flat crystals coincide, the mathematical relational expression of Pz1=B0, y+A0, Y and the sum of the planeness of each point of the Y-axis section on the flat crystals A and B and the two ideal planes of the flat crystals coincide can be obtained Ps1=bx, 0+A-x,0; k2, taking down the flat crystal B, replacing the flat crystal C, aligning coordinates of each point on the Y-axis section of the flat crystal A and the flat crystal C one by one, and measuring in the same way as the step K1, wherein the mathematical relation of the sum of the planeness of each point on the Y-axis section of the flat crystal A and the flat crystal C is P z2 ＝C 0,y +A 0,y And the mathematical relation of the sum of the flatness of each point of the X-axis cross section is P s2 ＝C x,0 +A -x,0 The method comprises the steps of carrying out a first treatment on the surface of the K3, taking down the flat crystal A, replacing the flat crystal B, aligning coordinates of each point on the Y-axis section on the flat crystal C and the flat crystal B one by one, and measuring in the same way as the step K1, wherein the mathematical relation of the sum of the planeness of each point on the Y-axis section on the flat crystal A and the flat crystal B is P z4 ＝C 0,y +B 0,y The flat crystal B is turned by 180 degrees to measure the sum of the planeness of each point of the X-axis cross section, and the mathematical relation of the sum of the planeness of each point of the X-axis cross section is obtained as P s4 ＝C x,0 +B x,0 The method comprises the steps of carrying out a first treatment on the surface of the K4, taking down the flat crystal C, replacing the flat crystal D, aligning coordinates of each point on the X-axis cross section of the flat crystal B and the flat crystal D one by one, and measuring in the same way as the step K1, wherein the mathematical relation of the sum of the planeness of each point on the X-axis cross section of the flat crystal C and the flat crystal D is P s5 ＝D x,0 +B x,0 Turning the flat crystal B into 180 degrees, measuring the sum of the planeness of each point of the Y-axis cross section, and obtaining the mathematical relation of the sum of the planeness of each point of the Y-axis cross section as P z5 ＝D 0,y +B 0,y The method comprises the steps of carrying out a first treatment on the surface of the K5, taking down the flat crystal B, replacing the flat crystal C, aligning coordinates of each point on the Y-axis section of the flat crystal D and the flat crystal C one by one, and measuring in the same way as the step K1, wherein the mathematical relation formula of the sum of the planeness of each point on the Y-axis section of the flat crystal D and the flat crystal C is P z6 ＝D 0,y +C 0,y The flat crystal C is turned to 180 degrees, the sum of the planeness of each point of the X-axis cross section is measured, and the mathematical relation of the sum of the planeness of each point of the X-axis cross section is obtained as P s6 ＝D x,0 +C x,0 The method comprises the steps of carrying out a first treatment on the surface of the K6, taking down the flat crystal C, replacing the flat crystal A, aligning coordinates of each point on the Y-axis section of the flat crystal D and the flat crystal A one by one, and measuring in the same way as the step K1, wherein the mathematical relation formula of the sum of the planeness of each point on the X-axis section is P s3 ＝D x,0 +A -x,0 Number of sums of flatness of points of Y-axis cross sectionThe chemical relationship is P z3 ＝D 0,y +A 0,y The method comprises the steps of carrying out a first treatment on the surface of the And K7, calculating the planeness of each point X on the X-axis cross sections of the flat crystals B, C and D, and calculating the planeness of each point X on the X-axis cross sections of the flat crystals A, and calculating the planeness of each point X on the X-axis cross sections of the flat crystals B, C and D. Substituting the sum of the planeness of Y-axis sections of flat crystal A, flat crystal B, flat crystal C and flat crystal D into P z1 ＝B 0,y +A 0,y ，P z2 ＝C 0,y +A 0,y ，P z4 ＝C 0,y +B 0,y ，P z5 ＝D 0,y +B 0,y ，P z6 ＝D 0,y +C 0,y ，P z3 ＝D 0,y +A 0,y The formula A can be obtained 0,y ＝[2(P z1 +P z2 +P z3 )-((P z4 +P z5 +P z6 )]/6，B 0,y ＝[2(P z1 +P z4 +P z5 )-((P z2 +P z3 +P z6 )]/6，C 0,y ＝[2(P z2 +P z4 +P z6 )-((P z1 +P z3 +P z5 )]/6，D 0,y ＝[2(P z3 +P z5 +P z6 )-((P z1 +P z2 +P z4 )]And/6, obtaining flatness deviation of each point of Y-axis cross sections of the flat crystals A, B, C and D after solving, and substituting the sum of the flatness of each point of X-axis cross sections of the flat crystals A, B, C and D into P s1 ＝B x,0 +A -x,0 ，P s2 ＝C x,0 +A -x,0 ，P s4 ＝C x,0 +B x,0 ，P s5 ＝D x,0 +B x,0 ，P s6 ＝D x,0 +C x,0 ，P s3 ＝D x,0 +A -x,0 The formula A can be obtained -x,0 ＝[2(P s1 +P s2 +P s3 )-((P s4 +P s5 +P s6 )]/6，B x,0 ＝[2(P s1 +P s4 +P s5 )-((P s2 +P s3 +P s6 )]/6，C x,0 ＝[2(P s2 +P s4 +P s6 )-((P s1 +P s3 +P s5 )]/6，D x,0 ＝[2(P s3 +P s5 +P s6 )-((P s1 +P s2 +P s4 )]And (6) calculating the flatness deviation of each point of the X-axis cross sections of the flat crystals A, B, C and D.
Example 3
Two flat crystal i point (x) obtained by phase shifting and checking double-section flatness i ,y i ) The theoretical plane of the sum of planeness of (a) may not pass through both end points of the plane crystal main section 1-2 section (i.e., the X-axis section) and may not be parallel to both end points of the 3-4 section (i.e., the Y-axis section). The treatment is required. The treatment is as follows: the two end points of the 1-2 section were treated as zero and the two end points of the 3-4 section were treated as parallel (see table 1 for treatment).
Table 1 calculation and processing of measured double cross-section flatness
The flatness deviation of the standard flat crystal can be corrected at this time. Examined plat crystal (x) i ,y i ) The correction value of the dot is a standard flat crystal (x i ,-y i ) The flatness of the dots deviates. And obtaining the flatness deviation of the checked flat crystal after correction. The standard flatness is double-section flatness, and the inspected flatness is double-section flatness. If the standard flat crystal flatness is multi-section flatness, the checked flat crystal is multi-section flatness. The flatness of the detected crystal is multi-section flatness, and can be expressed by a three-dimensional stereo image with nanometer as a unit.
Fig. 4 is a proprietary horizontal plane interferometer. Because the two supports for placing the flat crystals of the horizontal interferometer can lead the flat crystals not to deform by self weight, the horizontal interferometer can perform mutual inspection of the flat crystals. The mutual detection mode with four sides method should be adopted to ensure the measurement accuracy. The structure of the horizontal planar interferometer is shown in fig. 4, and a tubular reference illumination system is added in front of the fei-cable interferometer body diaphragm 415. The light source of the interferometer consists of an LED white light lamp 407 and an interference filter 408, or a white light source+monochromatic light source group And (3) forming the finished product. Light from the light source enters the tubular reference illumination system through the diaphragm 409 of the tubular reference light source, which is turned 90 ° by the mirror 414. The position of the mirror 414 is either in front of the second objective 206 of the tubular reference or behind it or behind the diaphragm 415, depending on the actual dimensions of these components. The figure is only schematic. The second objective, through which the light passes through the tubular fiducial, is focused on the interferometer's diaphragm 415, which diaphragm 415 is in turn at the focal plane of the interferometer's large lens 406. The light beam emitted by the diaphragm 415 is divergent light, reflected by the third half mirror 305 of the essential oil, and projected onto the large lens 406 to be parallel light, and projected onto the second flat crystal 404 and the first flat crystal 402 at a distance L between the working surfaces of the two flat crystals 8 Dimension L to a tubular reference 7 When equal or nearly equal, two coherent light beams reflected by the two plane crystal working surfaces pass through the half mirror 420, are imaged on the focal plane of the imaging objective lens, and are received by the third CCD device 416 provided therein. And displaying the interference fringes on the interferometer computer screen. By adjusting the interferometer first support 402, the two plane-to-plane working surfaces are parallel and the distance L between the two planes is achieved 8 And a tubular reference dimension L 7 Gradually equalizing, and performing phase shift treatment to obtain the sum of the planeness of each point of the two flat crystals. And obtaining the flatness deviation value of each point of the A, B, C, D four flat crystals by four-side mutual inspection and calculation. The uncertainty (k=3) of the verification is smaller than 0.01 μm, and the four flat crystals are all reference flat crystals, so that the method can be used for verification of standard flat crystals of the vertical plane interferometer. The second slab crystal support 405 of the horizontal patent interferometer has the functions of: the working face of the second flat crystal 404 is adjusted to be vertical to the light path, and the bracket and the flat crystal are correspondingly provided with scribing lines, so that each section can be aligned during detection. The second plano crystal 404 is adjusted concentric with the large lens 406 with a special tool. In addition to the above functions, the first flat crystal support 403 can also finely adjust the distance between the two flat crystals. The distance between the two flat crystals at the initial installation is equal to the tubular reference dimension. Also concentric with the large lens 406 is a special tool adjustment bracket 403. To ensure temperature stability during inspection, the interferometer has a thermal shield 413, and a thermal shield sliding door 401. All of the horizontal interferometers are mounted on respective supports and fixed to an instrument table 417. Instrument adjustmentSupport 418 adjusts instrument table 417 to bring the interferometer main optical axis to horizontal. The instrument adjustment support 418 is secured to the instrument base plate 419. The interferometer is placed on a vibration-proof stage. And (3) detecting the four cross-sectional flat crystals, wherein if the four cross-sectional flat crystals are detected according to the double-section flatness, the detecting result is a double-section flatness detecting result. If the test is carried out according to the multi-section flatness, the test result is a multi-section flatness test result.
There are three interferometers for reference instruments capable of multi-section flatness deviations, but none are now capable of measurement. The conventional horizontal phase-shifting interferometer cannot be verified temporarily because of no software for measuring the flatness deviation of multiple sections. The other two interferometers are respectively: horizontal plane isocline interferometers and patent horizontal plane interferometers. They have in common that they are much cheaper than horizontal phase shifting interferometers. The measurement efficiency of the horizontal type isodip interferometer is lower, but a 600/10000 horizontal type isodip plane interferometer can detect the flat crystals with various specifications within D600 and the grinding flat ruler with the size within 1000 mm. The other two plane interferometers cannot detect the flat crystals with the caliber larger than that of the small-caliber instrument. The disadvantage of horizontal plane alike interferometers is their low efficiency and their large influence by temperature. The horizontal plane interferometer is a horizontal plane interferometer adopting a tubular reference illumination system. It has low cost, can use tubular standard to shift phase, high measuring efficiency, and can change the two-phase surface from nearly close contact to tens of millimeters or more and still obtain zero-order interference fringe or clear monochromatic light interference fringe. The temperature error caused by unstable temperature is greatly reduced while the measurement accuracy is ensured. The device is low in cost, can replace a horizontal phase-shifting plane interferometer completely in function, and can measure more length measurement items, particularly a vertical patent plane interferometer. Such as: measurement after plating and coating can be measured without any change, measurement of standard gap gauge size difference. And a comparative measurement of the center length of the gauge block. Both of these instruments also require design and manufacturing, and are not technically difficult. For the national metering department, a horizontal plane isodip interferometer is required to be established for detecting the flat crystals of various specifications. And a D150mm patent horizontal plane interferometer for detecting a plurality of D150 flat crystals.
The purpose of realizing the multi-section flatness deviation measurement is to eliminate the influence of the flatness deviation of the standard flat crystal on the image thereof in the three-dimensional stereo distribution diagram for the flatness deviation. To make the multi-section flatness deviation measurement, a multi-section flatness reference flat must be established. The standard flat crystal is used for calibrating the vertical patent plane interferometer, so that the flat crystal carried by the interferometer has correction quantity of multi-section flatness deviation. The calibration junction is corrected, so that the flatness deviation of the measured surface can be represented by a three-dimensional stereograph when the high-precision flatness is measured, and the influence of the standard flat crystal flatness deviation on the three-dimensional stereograph is eliminated. The establishment of the multi-section flatness reference flat crystal is obtained by mutually detecting four flat crystals. The measuring steps are as follows:
t1, selecting measuring points, namely establishing 6 uniformly distributed detected sections for the flat crystals with the diameters less than or equal to 200mm, wherein each section is separated by 30 degrees, and each section uses a plurality of measured points which are measuring points of the surfaces to be measured with various diameters, so that correction is facilitated. And placing the inscription mark of the flat crystal non-working surface at a position of 45 degrees in the third quadrant. And (4) enabling the working surface of the flat crystal to face upwards, and taking the center point of the flat crystal as the origin of coordinates. The clear aperture of the interferometer with a D150mm aperture was 142mm, and no visually visible sagging was found in the D142mm range. The working surface range is D140mm, and 6 examined sections are arranged in anticlockwise order. The X-axis section is 1-7 sections, and the Y-axis section is 4-10 sections. On the cylindrical surface of the flat crystal, the two ends of the X-axis cross section are plated with a scribing line, the left end is marked as 1, and a scribing line and corresponding serial numbers are marked every 30 degrees anticlockwise until reaching 12. The X-axis cross-sectional coordinates are negative to positive from left to right, i.e., -70, -46, -36, -27, 0, +27, +36, +46, +70, 9 points per cross-section. The X-axis section is 2-8 sections at 30 degrees anticlockwise, and the section perpendicular to the X-axis section is 5-11 sections. The X-axis section is a section of 3-9 at 60 degrees anticlockwise, and the section perpendicular to the X-axis section is a section of 6-12. For D200, the plane crystal is increased by two points-94 and +94. The coordinates of each flat crystal measurement point are the same. The center of the flat crystal is a common point, and is the origin of coordinates, namely 0 point. The diameter of the flat crystal is 250-450 mm, 12 diameter sections are taken in the circumferential direction, each section interval is 15 degrees, and 21 points, namely +219 and +194, are measured by the original 6 sections. +169, +144, +119. +94, +70, +48, +38, +28, 0, -28, -38, -48, -70, -94, -119, -144, -169, -194, -219. The 6 sections of the new album only measure 10 points and 0 points of the new album.
T2, the steps K1-K7 are four-sided verification of X-axis cross section and Y-axis cross section of double-section flatness, namely four-sided verification is carried out on 1-7 cross section and 4-10 cross section of the double-plane crystal. The four-side method of the multi-section flatness is also used for four-side method verification of 2-8 sections and 5-11 sections, 3-9 sections and 6-12 sections of the two flat crystals. The coplanarity of 12 endpoints of 6 sections was also examined for every two flat crystals. In order to reduce the adjustment of the flat crystals, after every two flat crystals are installed and phase-shifted, all verification items on the two flat crystals are verified, and the flat crystals can be replaced. When the two flat crystals perform all the operations, the second flat crystal 404 placed on the second support frame 405 of the horizontal interferometer in fig. 4 is not moved, but only the first flat crystal 402 placed on the first support frame 403 of the horizontal interferometer. When the flat crystal is observed from the direction of the imaging objective lens, the serial numbers of the points of the second flat crystal 404 are arranged clockwise, and the serial numbers of the points of the first flat crystal 402 are arranged anticlockwise, as shown in fig. 3. After the operation is performed to phase shift, a first set of four-side method measurement is performed, the sum of straightness degrees of 0 at two ends of 1-7 sections of the two flat crystals and the sum of coplanarity of 12 section end points are read together, and ideal plane processing is performed. The ideal plane treatment is because its ideal plane passes through its points 1 and 7 and is parallel to points 4 and 10. Namely A 1 ＝0，A 7 ＝0，A 4 ＝A 10 ；B 1 ＝0，B 7 ＝0，B 4 ＝B 10 . So to coincide the ideal planes of the two planar crystals, the data for point 1 and point 7 are processed to be 0 and the data for point 4 and point 10 are processed to be equal for the data for the coplanarity measurement. The first flat crystal 402 is rotated 180 deg. to align its 4-10 cross-section with the points of the 4-10 cross-section of the second flat crystal 404 one-to-one. All operations before and after phase shift are carried out, and the sum of the straightness of 0 at the two ends of the 4-10 section of the two flat crystals is read. Then the first flat crystal 402 is rotated 30 degrees clockwise to perform all operations before and after phase shift, and 12 sections are readAnd the sum of the coplanarity of the endpoints, and processing the measured data into an ideal plane. The first flat crystal 402 is continuously rotated 30 degrees clockwise, at this time, the points of the 2-8 sections of the two flat crystals are aligned one by one, all operations before and after phase shifting are carried out, the sum of straightness degrees of the two ends of the 2-8 sections of the two flat crystals is read, and the sum of coplanarity of the end points of the 12 sections is read, so that ideal plane processing is carried out. The first flat crystal 402 is turned 180 degrees to align the 5-11 section points with the 5-11 section points of the second flat crystal 404 one by one, all operations before and after phase shifting are carried out, and the sum of the straightness of 0 at the two ends of the 5-11 section of the two flat crystals is read. The first flat 402 is rotated again by 30 ° clockwise and rotated cumulatively by 90 °. All operations before and after phase shift are carried out, the sum of coplanarity of the endpoints of 12 sections is read, and ideal plane processing is carried out. The first flat crystal 402 is rotated clockwise by 30 degrees again and rotated cumulatively by 120 degrees. The points of the 3-9 sections of the two flat crystals are aligned one by one. All operations before and after phase shift are carried out, the sum of straightness of 0 at two ends of a 3-9 section of the two flat crystals and the sum of flatness of end points of 12 sections are read, and ideal plane processing is carried out. The first flat crystal 402 is rotated 180 deg. to align its 6-12 cross-section with the points of the 6-12 cross-section of the second flat crystal 404 one by one. All operations before and after phase shift are carried out, and the sum of the straightness of 0 at the two ends of the 6-12 section of the two flat crystals is read. Thereafter, the first flat crystal 402 is rotated 30 ° clockwise each time, all operations before and after phase shift are performed, and the sum of the flatness of the end points of the 12 sections is read and subjected to ideal plane processing. Until the first flat 402 rotates 330 deg. clockwise, all operations before and after phase shift are performed, the last reading of the sum of the flatness of the end points of the 12 sections is performed, and ideal plane processing is performed. After the three groups of four-side methods are calibrated, the straightness deviation of 6 sections of four flat crystals can be obtained by calculation according to the same formula in K1-K7. And calculating the coplanarity deviation of each end point of the cross section of each flat crystal by using a formula for calculating the coplanarity of each end point of the cross section, wherein each flat crystal has three coplanarity deviations, and taking the average value of the three results as the final coplanarity deviation result. And then superposing the straightness deviation of the 6 sections of the flat crystal on the coplanarity deviation of the end points of the sections 12. The deviation of flatness of the multiple sections of the flat crystal can be obtained.
T3, calculating coplanarity of each end point of the multi-section flatness deviation circumference, and vertically placing two flat crystals in a horizontal typeOn two supports 403 and 405 of the planar interferometer, the crystal placed at the position of the second crystal 404 of the instrument is the crystal a, and the crystal placed at the position of the first crystal 402 of the instrument is the crystal B. (taking 150 flat crystals as an example), two flat crystal working surfaces are opposite, the horizontal cross sections of the two flat crystals are 1-7 cross sections, and A 1 Pair B 1 ,A 7 Pair B 7 . I.e. the points of the 1-7 sections of the flat crystals A and B are aligned one by one. Other cross section flat crystals B are arranged anticlockwise, and flat crystals A are arranged clockwise. And the other coordinates of the two flat crystals cannot be aligned with each point. Before and after the phase shift operation is completed, the sum of straightness deviations of points with zero end points of the 1-7 sections of the flat crystal A-B combination is measured. And the 1 st indexing measurement back of coplanarity of all cross section endpoints of the flat crystal A-B combination circumference is carried out, and ideal plane processing is carried out. But the 4-10 cross section of plane a is aligned with the 10-4 section of plane B. The alignment of points of the 4-10 sections of the two flat crystals can be realized only by turning the flat crystal B by 180 degrees. After rotation, the operation before and after phase shift is performed, and the sum of straightness deviation of points with zero end points of the 4-10 section of the A-B combined two-plane crystal can be measured. For calculation by four-side method. 1 st indexing back d for measuring coplanarity of points of two flat crystals i-j Because zero-order interference fringes appear in the center of a view field between two flat crystal ideal planes, the two flat crystal ideal planes are intersected, no distance exists between the two flat crystal ideal planes, the zero-order interference fringes are widened to be extremely wide, and the interference fringes still have a tiny included angle and a tiny distance L after phase shifting. The treatment must be performed such that the ideal planes of the two flat crystals coincide, i.e. the ideal plane treatment. The included angle between each point of the flat crystal A and the center of the circle of 1 point is theta i The included angle between two adjacent points is 30 degrees, and the method is that:
d 1-1 ＝A 1 +B 1 +L 1 －L 1 －(A 1 +A 7 +B 1 +B 7 )/2+cos0°(A 7 －A 1 +B 7 －B 1 )/2+sin0°(A 10 －A 4 +B 4 －B 10 )/2＝0
d 2-12 ＝A 2 +B 12 +L 1 －L 1 －(A 1 +A 7 +B 1 +B 7 )/2+cos30°(A 7 －A 1 +B 7 －B 1 )/2+sin30°(A 10 －A 4 +B 4 －B 10 )/2
d 3-11 ＝A 3 +B 11 +L 1 －L 1 －(A 1 +A 7 +B 1 +B 7 )/2+cos60°(A 7 －A 1 +B 7 －B 1 )/2+sin60°(A 10 －A 4 +B 4 －B 10 )/2
d 4-10 ＝A 4 +B 10 +L 1 －L 1 －(A 1 +A 7 +B 1 +B 7 )/2+cos90°(A 7 －A 1 +B 7 －B 1 )/2+sin90°(A 10 －A 4 +B 4 －B 10 )/2＝k 1
d 5-9 ＝A 5 +B 9 +L 1 －L 1 －(A 1 +A 7 +B 1 +B 7 )/2+cos120°(A 7 －A 1 +B 7 －B 1 )/2+sin120°(A 10 －A 4 +B 4 －B 10 )/2
d 6-8 ＝A 6 +B 8 +L 1 －L 1 －(A 1 +A 7 +B 1 +B 7 )/2+cos150°(A 7 －A 1 +B 7 －B 1 )/2+sin150°(A 10 －A 4 +B 4 －B 10 )/2
d 7-7 ＝A 7 +B 7 +L 1 －L 1 －(A 1 +A 7 +B 1 +B 7 )/2+cos180°(A 7 －A 1 +B 7 －B 1 )/2+sin180°(A 10 －A 4 +B 4 －B 10 )/2＝0
d 8-6 ＝A 8 +B 6 +L 1 －L 1 －(A 1 +A 7 +B 1 +B 7 )/2+cos210°(A 7 －A 1 +B 7 －B 1 )/2+sin210°(A 10 －A 4 +B 4 －B 10 )/2
d 9-5 ＝A 9 +B 5 +L 1 －L 1 －(A 1 +A 7 +B 1 +B 7 )/2+cos240°(A 7 －A 1 +B 7 －B 1 )/2+sin240°(A 10 －A 4 +B 4 －B 10 )/2
d 10-4 ＝A 10 +B 4 +L 1 －L 1 －(A 1 +A 7 +B 1 +B 7 )/2+co270°(A 7 －A 1 +B 7 －B 1 )/2+sin270°(A 10 －A 4 +B 4 －B 10 )/2＝k 1
d 11-3 ＝A 11 +B 3 +L 1 －L 1 －(A 1 +A 7 +B 1 +B 7 )/2+cos300°(A 7 －A 1 +B 7 －B 1 )/2+sin300°(A 10 －A 4 +B 4 －B 10 )/2
d 12-2 ＝A 12 +B 2 +L 1 －L 1 －(A 1 +A 7 +B 1 +B 7 )/2+cos330°(A 7 －A 1 +B 7 －B 1 )/2+sin330°(A 10 －A 4 +B 4 －B 10 )/2
k 1 ＝(A 10 +A 4 +B 4 +B 10 )/2－(A 1 +A 7 +B 1 +B 7 )/2
k 2 ＝(A 10 +A 4 +B 4 +B 10 )/2－(A 1 +A 7 +B 1 +B 7 )/2＝k 1
wherein: l (L) 1 For the first adjustment and the micro distance between the two ideal planes of the two flat crystal circumference points after the phase shift, the following subtraction is the adjustment required by the adjustment coincidence of the two ideal planes. After the measurement, the flat crystal B rotates clockwise by θ=pi/N=30°, θ i Is the central angle of each point of the flat crystal A to 1 point. θ i I pi/N (where n= 6,i =0, 1, … … 11), adjusting both of the plane crystals B and BA are parallel and have a small distance apart. At this time A 1 Pair B 2 ,A 7 Pair B 8 . No cross section is corresponding. 2 nd indexing back d capable of measuring coplanarity of each section end point of two flat crystals only i-j At this time, the ideal plane of flat crystal a is made coincident with the reference plane of flat crystal B, which passes through points 2 and 8 of flat crystal B and is parallel to points 5 and 11 of flat crystal B. In the data processing, the reference plane of the flat crystal B is overlapped with the ideal plane of the flat crystal A, and the processed result d can be obtained i-j The geometrical relationship between the flatness deviation of the measured point and the relevant point of the reference plane is as follows:
d 1－2 ＝A 1 +B 2 +L 2 －L 2 －(A 1 +A 7 +B 2 +B 8 )/2+cos0°(A 7 －A 1 +B 8 －B 2 )/2+sin0°(A 10 －A 4 +B 5 －B 11 )/2＝＝0
d 2－1 ＝A 2 +B 1 +L 2 －L 2 －(A 1 +A 7 +B 2 +B 8 )/2+cos30°(A 7 －A 1 +B 8 －B 2 )/2+sin30°(A 10 －A 4 +B 5 －B 11 )/2
d 3－12 ＝A 3 +B 12 +L 2 －L 2 －(A 1 +A 7 +B 2 +B 8 )/2+cos60°(A 7 －A 1 +B 8 －B 2 )/2+sin60°(A 10 －A 4 +B 5 －B 11 )/2
d 4－11 ＝A 4 +B 11 +L 2 －L 2 －(A 1 +A 7 +B 2 +B 8 )/2+cos90°(A 7 －A 1 +B 8 －B 2 )/2+sin90°(A 10 －A 4 +B 5 －B 11 )/2＝k 3
d 5－10 ＝A 5 +B 10 +L 2 －L 2 －(A 1 +A 7 +B 2 +B 8 )/2+cos120°(A 7 －A 1 +B 8 －B 2 )/2+sin120°(A 10 －A 4 +B 5 －B 11 )/2
d 6－9 ＝A 6 +B 9 +L 2 －L 2 －(A 1 +A 7 +B 2 +B 8 )/2+cos150°(A 7 －A 1 +B 8 －B 2 )/2+sin150°(A 10 －A 4 +B 5 －B 11 )/2
d 7－8 ＝A 7 +B 8 +L 2 －L 2 －(A 1 +A 7 +B 2 +B 8 )/2+cos180°(A 7 －A 1 +B 8 －B 2 )/2+sin180°(A 10 －A 4 +B 5 －B 11 )/2＝0
d 8－7 ＝A 8 +B 7 +L 2 －L 2 －(A 1 +A 7 +B 2 +B 8 )/2+cos210°(A 7 －A 1 +B 8 －B 2 )/2+sin210°(A 10 －A 4 +B 5 －B 11 )/2
9 9－6 ＝A 9 +B 6 +L 2 －L 2 －(A 1 +A 7 +B 2 +B 8 )/2+cos240°(A 7 －A 1 +B 8 －B 2 )/2+sin240°(A 10 －A 4 +B 5 －B 11 )/2
d 10－5 ＝A 10 +B 5 +L 2 －L 2 －(A 1 +A 7 +B 2 +B 8 )/2+cos270°(A 7 －A 1 +B 8 －B 2 )/2+sin270°(A 10 －A 4 +B 5 －B 11 )/2＝k 4 ＝k 3
d 11－4 ＝A 11 +B 4 +L 2 －L 2 －(A 1 +A 7 +B 2 +B 8 )/2+cos300°(A 7 －A 1 +B 8 －B 2 )/2+sin300°(A 10 －A 4 +B 5 －B 11 )/2
d 12－3 ＝A 12 +B 3 +L 2 －L 2 －(A 1 +A 7 +B 2 +B 8 )/2+cos330°(A 7 －A 1 +B 8 －B 2 )/2+sin330°(A 10 －A 4 +B 5 －B 11 )/2
k 3 ＝(A 10 +A 4 +B 5 +B 11 )/2－(A 1 +A 7 +B 2 +B 8 )/2
k 4 ＝(A 10 +A 4 +B 5 +B 11 )/2－(A 1 +A 7 +B 2 +B 8 )/2＝k 3
after this set of test returns, the flat crystal B is rotated again clockwise by θ=pi/N and adjusted appropriately, and the same goes to obtain:
d 1－3 ＝A 1 +B 3 +L 3 －L 3 －(A 1 +A 7 +B 3 +B 9 )/2+cos0°(A 7 －A 1 +B 9 －B 3 )/2+sin0°(A 10 －A 4 +B 6 －B 12 )/2＝0
d 2－2 ＝A 2 +B 2 +L 3 －L 3 －(A 1 +A 7 +B 3 +B 9 )/2+cos30°(A 7 －A 1 +B 9 －B 3 )/2+sin30°(A 10 －A 4 +B 6 －B 12 )/2
d 3－1 ＝A 3 +B 1 +L 3 －L 3 －(A 1 +A 7 +B 3 +B 9 )/2+cos60°(A 7 －A 1 +B 9 －B 3 )/2+sin60°(A 10 －A 4 +B 6 －B 12 )/2
d 4－12 ＝A 4 +B 12 +L 3 －L 3 －(A 1 +A 7 +B 3 +B 9 )/2+cos90°(A 7 －A 1 +B 9 －B 3 )/2+sin90°(A 10 －A 4 +B 6 －B 12 )/2＝k 5
d 5－11 ＝A 5 +B 11 +L 3 －L 3 －(A 1 +A 7 +B 3 +B 9 )/2+cos120°(A 7 －A 1 +B 9 －B 3 )/2+sin120°(A 10 －A 4 +B 6 －B 12 )/2
d 6－10 ＝A 6 +B 10 +L 3 －L 3 －(A 1 +A 7 +B 3 +B 9 )/2+cos150°(A 7 －A 1 +B 9 －B 3 )/2+sin150°(A 10 －A 4 +B 6 －B 12 )/2
d 7－9 ＝A 7 +B 9 +L 3 －L 3 －(A 1 +A 7 +B 3 +B 9 )/2+co180°(A 7 －A 1 +B 9 －B 3 )/2+sin180°(A 10 －A 4 +B 6 －B 12 )/2＝0
d 8－8 ＝A 8 +B 8 +L 3 －L 3 －(A 1 +A 7 +B 3 +B 9 )/2+cos210°(A 7 －A 1 +B 9 －B 3 )/2+sin210°(A 10 －A 4 +B 6 －B 12 )/2
d 9－7 ＝A 9 +B 7 +L 3 －L 3 －(A 1 +A 7 +B 3 +B 9 )/2+cos240°(A 7 －A 1 +B 9 －B 3 )/2+sin240°(A 10 －A 4 +B 6 －B 12 )/2
d 10－6 ＝A 10 +B 6 +L 3 －L 3 －(A 1 +A 7 +B 3 +B 9 )/2+cos2700°(A 7 －A 1 +B 9 －B 3 )/2+sin270°(A 10 －A 4 +B 6 －B 12 )/2＝k 6 ＝k 5
d 11－5 ＝A 11 +B 5 +L 3 －L 3 －(A 1 +A 7 +B 3 +B 9 )/2+cos300°(A 7 －A 1 +B 9 －B 3 )/2+sin300°(A 10 －A 4 +B 6 －B 12 )/2
d 12－4 ＝A 12 +B 4 +L 3 －L 3 －(A 1 +A 7 +B 3 +B 9 )/2+cos330°(A 7 －A 1 +B 9 －B 3 )/2+sin330°(A 10 －A 4 +B 6 －B 12 )/2
K 5 ＝(A 10 +A 4 +B 6 +B 12 )/2－(A 1 +A 7 +B 3 +B 9 )/2
K 6 ＝(A 10 +A 4 +B 6 +B 12 )/2－(A 1 +A 7 +B 3 +B 9 )/2＝k 5
in the 12 combinations, j is a combination serial number, and when j is an odd number, the (j+1)/2- (j+1)/2+6 cross section of the two flat crystals of the combination and the (j+1+6)/2- (j+1+6)/2+6 cross section straightness of the two flat crystals of the first flat crystal 402 rotated 180 degrees can also be measured. The same thing can obtain that in the i-test, the flat crystal B rotates clockwise by theta i Angle, theta i =i pi/6. The general formula for the adjusted measurement can be derived: j is the number of the point 1 of the flat crystal A corresponding to the point of the flat crystal B in the J check. When D is less than or equal to 200, n=12. In this test, when i.ltoreq.J: the data processed by the first point is d 1-j The next point data is d i+1--j-1 Serial number of the crystal is equal to serial number +1 of the crystal A, and serial number-1 of the crystal B. When the measuring point serial number j of the flat crystal B is less than or equal to 0, j+n can be used as the serial number. Measuring point number j of flat crystal B>12, j-n can be used as its sequence number.
d 1－j ＝A 1 +B j +L j －L j －(A 1 +A 7 +B j +B j+6 )/2+cos0°(A 7 －A 1 +B j+6 －B j )/2+sin0°(A 10 －A 4 +B j+3 －B j+9 )/2＝0
d 2－(J－i) ＝A 2 +B (J－i) +L j －L j －(A 1 +A 7 +B j +B j+6 )/2+cos30°(A 7 －A 1 +B j+6 －B j )/2+sin30°(A 10 －A 4 +B j+3 －B j+9 )/2
d 3－(J－2) ＝A 3 +B (J－2) +L j －L j －(A 1 +A 7 +B j +B j+6 )/2+cos60°(A 7 －A 1 +B j+6 －B j )/2+sin60°(A 10 －A 4 +B j+3 －B j+9 )/2
d 4－(J－3) ＝A 4 +B (J－3) +L j －L j －(A 1 +A 7 +B j +B j+6 )/2+cos90°(A 7 －A 1 +B j+6 －B j )/2+sin90°(A 10 －A 4 +B j+3 －B j+9 )/2＝k
……
When i is less than or equal to J, the reading of i point is processed
d i－(j－i+1) ＝A i +B (j－i+1) +L j －L j －(A 1 +A 7 +B j +B j+6 )/2+cosθ i－1 (A 7 －A 1 +B j+6 －B j )/2+sinθ i－1 (A 10 －A 4 +B j+3 －B j+9 )/2
When i > J, the i point reading is processed to be (n=12)
d i－(j+n－i+1) ＝A i +B (j+n－i+1) +L j －L j －(A 1 +A 7 +B j +B j+6 )/2+cosθ i－1 (A 7 －A 1 +B j+6 +B j )/2+sinθ i－1 (A 10 －A 4 +B j+3 －B j+9 )/2
……
d 12－(j+i) ＝A 12 +B (j+1) +L 12 －L 12 －(A 1 +A 7 +B j +B j+6 )/2+cos330°(A 7 －A 1 +B j+6 +B j )/2+sin330°(A 10 －A 4 +B j+3 －B j+9 )/2
And (3) sequentially completing indexing and detecting back, rotating the flat crystal B by θ=pi/6=30 degrees relative to the flat crystal A clockwise, properly adjusting, measuring Cheng Chazhi of each point of the circumference, and performing numerical processing. Until the last test back is completed. The points of the flat crystal B and the flat crystal A in 12 graduation measurement returns 1 The point measurement values are all added to obtain:
the final calculation results of the i point on the flat crystal A and the points of the flat crystal B at 12 graduation measuring back are all added, and the following steps can be obtained:
and the sum of each point of the flat crystal B and the verification set of a certain point of the flat crystal A is n times of the flatness deviation of the point, and the flatness deviation of the point of the flat crystal A is obtained by dividing the value by n. And dividing the sum of the verification set of each point of the same flat crystal B and a certain point of the flat crystal A by n to obtain the flatness deviation of the point of the flat crystal B.
Thus, the flatness coplanarity of each end point of the circumference of the cross section of the flat crystals A and B is obtained, mutual inspection is needed, each block has three verification results, and the average value of three times is taken as the final result of the three verification results.
And T4, calculating the flatness deviation of the multiple sections, and superposing the flatness deviation of each section on a corresponding point of the coplanarity after four planar crystals respectively obtain the four-side average result of the straightness of each section and the coplanarity average value of each section endpoint. The deviation of the flatness of the multiple sections of each flat crystal can be obtained. The calculation process is shown in tables 2 and 3.
TABLE 2 coplanarity deviations of the endpoints of each section and straightness deviations of each section
TABLE 3 Multi-section flatness deviations with each section straightness deviation superimposed on each section endpoint coplanarity deviation
Three-dimensional stereographic map of flatness deviations. After obtaining the multi-section flatness deviations, software is needed to solve how to turn these data into images. First, there is no large flatness deviation in the part of the flat crystal, and the reading gradually transits. The flatness deviations within the triangle of three arbitrarily adjacent stations of different circles are thus linearly transitional. As shown in fig. 5, three points a (x a ,y a )、B(x b ,y b )、C(x c ,y c )，Z a 、Z b 、Z c Is the flatness deviation of three points, which are respectively on two adjacent circles and Z a 、Z b 、>k,Z c <k, or Z a >k,Z b 、Z c >k, find the x point of flatness deviation k, i.e. Z x =k. The D point or E point can be found in the AC, BC line segment in Δabc. Or find the D point or E point in the AC, AB line segment in Δabc.
When the point A and the point B are on the outer ring and the point C is on the inner ring:
or when the point A is on the outer ring, and the points B and C are on the inner ring:
and D and E points in delta ABC are obtained, the flatness deviation of any point on the connecting line DE and the line segment DE is equal to k. And (3) all other deltas conforming to the delta ABC characteristic are made into line segments with the flatness deviation equal to k, and a closed curve with the flatness deviation equal to k can be obtained. Different closed curves can be obtained by setting different k values. If the difference between the k values is a fixed number of nanometers. A three-dimensional stereographic of flatness deviation in units of several nanometers can be obtained.
Although the invention has been described herein with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the scope and spirit of the principles of this disclosure. More specifically, various variations and modifications may be made to the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, drawings and claims of this application. In addition to variations and modifications in the component parts and/or arrangements, other uses will be apparent to those skilled in the art.
Claims (7)
1. A fizeau interferometer with a tubular reference illumination system, characterized by comprising a fizeau interferometer body (1) and a tubular reference illumination system, the tubular reference illumination system being arranged between a light source (200) and a second diaphragm (207) of the fizeau interferometer body (1), the light source (200) being white light + a first interference filter (110) or white light + monochromatic light;
the tubular reference lighting system comprises a first diaphragm (201), a first objective lens (202), a first silver plating small plat crystal (203), a first tubular reference main body (204), a second silver plating small plat crystal (205) and a second objective lens (206), wherein one end of the first tubular reference main body (204) is glued or glued with the first silver plating small plat crystal (203), the other end of the first tubular reference main body is glued or glued with the second silver plating small plat crystal (205), the first diaphragm (201) and the first objective lens (202) are fixed on one side, which is connected with the first tubular reference main body (204) and the first silver plating small plat crystal (203), the second objective lens (206) is fixed on the other side of the first tubular reference main body (204) through a second support, the first diaphragm (201) is positioned on the focal plane of the first objective lens (202), light rays emitted by the light source (200) become divergent lights (101) after passing through the first diaphragm (201), the parallel lights (102) are formed by the first objective lens (202), the parallel lights (102) enter the divergent lights (103) through the tubular reference main body (103) in sequence, the second diaphragm (103) are converged by the first diaphragm (203) and the second lens (103) in sequence, the second diaphragm (207) is located on the focal plane of the second objective (206).
2. A fizeau interferometer with a tubular reference illumination system according to claim 1, characterized in that: the device is characterized in that a standard plat crystal and a checked plat crystal are arranged in the Fidelity interferometer body (1), the distance between the standard plat crystal and the checked plat crystal is L2, the length of the first tubular reference main body (204) is L1, and the converged light rays (103) sequentially irradiate the standard plat crystal and the checked plat crystal after passing through a light path system in the Fidelity interferometer body (1)On the detected flat crystal, the optical path system comprisesCCD device (307)。
3. A fizeau interferometer with a tubular reference illumination system according to claim 2, characterized in that: the side of first tubulose benchmark main part (204) is provided with two inside and outside penetrating M5 screw, two the M5 screw respectively demountable installation has digital micropressure meter and air pump, standard plat form is fixed through first mounting bracket, the plat form of being examined is fixed through the second mounting bracket.
4. A fizeau interferometer with a tubular reference illumination system according to claim 1, characterized in that: the light source (200) further comprises an LED lamp (601) and a second interference filter (602), the tubular reference lighting system further comprises a turntable (608), a third silver plating small flat crystal (611), a second tubular reference main body (612) and a fourth silver plating small flat crystal (613), and the Sophie interferometer body (1) comprises a second CCD device (618), a second reflector (616), an observation objective lens (619), a half reflector (620), a main lens (621), a main flat crystal (622), a gauge block (623), a working flat crystal (624) and a workbench (609); after the parallel light rays (102) are emitted out through the second silver plating small flat crystal (205), the parallel light rays irradiate onto a third silver plating small flat crystal (611) through a through hole of a rotary table (608), then the parallel light rays (102) sequentially pass through the third silver plating small flat crystal (611), a second tubular reference main body (612) and a fourth silver plating small flat crystal (613), converging light rays (103) are formed through a second objective lens (206), second diverging light rays are formed after the converging light rays (103) pass through a second diaphragm (207), the converging light rays pass through a second reflecting mirror (616) and a half reflecting mirror (620) and are projected onto a main lens (621), the second diverging light rays are changed into second parallel light rays from the main lens (621), the second parallel light rays pass through an interferometer main flat crystal (622) and reach a working flat crystal (624) and a gauge block (623) which is lapped on the working surface of the working flat crystal (624), and the working flat crystal (624) is placed on the working table (609);
When the distance L from the working surface of the main crystal (622) to the working surface of the working crystal (624) of the interferometer 6 And a first tubular reference dimension L 3 When the phases are equal to each other,zero-order interference fringes appear on the surface of the working flat crystal (624), and the dimension L of the detected block (623) 5 Dimension L with the second tubular reference body (612) 4 Equally, zero-order interference fringes appear on the surface of the gauge block (623), at the moment, the downward movement amount of the workbench (609) is larger than 100mm, the working flat crystal (624) is arranged on the workbench (609) with movable and adjustable level, the workbench (609) is fixed on the base (624) of the interferometer, when the surface of the working flat crystal (624) is vertical to the optical axis, namely, parallel to the main flat crystal (622), and the distance L between the surface of the working flat crystal (624) and the main flat crystal (622) 6 Dimension L to the first tubular reference body (204) 3 When the difference is smaller than the monochromatic light interference capability, an interference pattern appears on the surface of the working flat crystal (624), and the dimension L of the detected block (623) 5 Dimension L with the second tubular reference body (612) 4 Equally, interference patterns are present on the working surface of the gauge block (623), the stage (609) is adjusted so that the interference fringes are parallel to the short sides of the gauge block (623), and simultaneously white light and monochromatic light are used for illumination, and the stage (609) is adjusted so that L 6 And L is equal to 3 When the gap is smaller than 3 μm, a group of white light zero-order interference fringes are overlapped on the interference field of the gauge block (623) and the working flat crystal (624), the zero-order black fringes are adjusted to be arranged at the center of the gauge block (623), if the zero-order fringes of the working flat crystal (624) are on the same straight line with the zero-order fringes when leaving, the size of the size difference between the two zero-order fringes is determined according to the size of the zero-order fringes, when the gap is increased, the gauge block is +offset when the size difference is increased, otherwise, the gauge block is-offset, the interference patterns on the surface of the interference field adopt monochromatic light illumination, the interference patterns are imaged near the focal plane of the observation objective (619) through the main lens (621), the half-mirror (620) and the observation objective (619), a second CCD device (618) is arranged at the position, the interference patterns are transmitted to a computer screen to give verification result, and if the gauge block on the working flat crystal (624) is the same size as the gauge block of the two gauge blocks, and the third gauge block (611) is removed, and the fourth gauge block (613) is slightly smaller than the first gauge block (623) is removed from the tubular gauge block (611) The zero-order black stripes on the block (623) have a pitch, one of which is 1 equal gauge block, the length dimension of which is known, the dimension of the other gauge block is the number of stripes of the pitch multiplied by half wavelength of monochromatic light + the known gauge block dimension correction, the pitch is measured by using the integer number of stripes determined by white light zero-order black stripes, the fraction of stripes is measured by using monochromatic light, if the size of the gauge block (623) is the same as the size of a steel ball, the steel ball size can be verified, the three-wire size can be verified similarly, the gauge block dimension difference of the standard gap of a verification knife edge can be measured similarly, and the plating or coating thickness on a flat crystal can also be measured, the second objective (206), the second diaphragm (207), the second reflector (616), the half mirror (620), the observation objective (619), the second CCD device (618), the main lens (621) and the main flat crystal (622) are all arranged on the second support of the interferometer, when the installation and adjustment are performed, the main optical axis exists in the horizontal plane, the workbench (609) is a component, the up-down moving range of which is not less than 100mm, so as to detect the gauge block with the inner size of 100mm, and has a grating component displaying the position, the resolution of which can be displayed to micrometer, and is displayed in a computer screen, the working surface of the working flat crystal (624) generates zero black stripes, and the working flat crystal (624) is different according to different purposes by the horizontal diameter of the working flat crystal (624) as the zero position of the grating, the working flat crystal (624) is used for verifying the gauge block and the like to have the steel flat crystal and the working flat crystal (624) with the center non-plating film width of 10mm, the working flat crystal (624) for comparison measurement is a common non-coated flat crystal and is used for detecting 1 equivalent gauge block, a second tubular reference (612) is placed in a counter bore of a through hole of a rotary table (608) of the interferometer, the second tubular reference (612) consists of a third silver plating small flat crystal (611), a fourth silver plating small flat crystal (613) and a second tubular reference main body (612), the third silver plating small flat crystal (611) and the fourth silver plating small flat crystal (613) are respectively light glued on working surfaces at two ends of the second tubular reference main body (612), the parallelism of the working surfaces at two ends of the second tubular reference main body (612) is less than 0.1 mu m, and the dimension L of the second tubular reference main body (612) 4 To achieve 1X 10 wavelength uncertainty -8 When the working table is adjusted to be at the 0 position, interference fringes appear on the working surface of the working flat crystal (624), zero-order black fringes are adjusted to be at the center of the working surface of the working flat crystal (624), and short sides of the gauge blocks are parallel and equivalentSize L of block (623) 3 When the second tubular reference dimension L4 is equal, zero-order black stripes appear in the center of the gauge block (623), the black stripes on the gauge block (623) are in a straight line with the black stripes on the working flat crystal (624), or the zero-order black stripe connecting lines on the working flat crystal (624) are intersected with the black stripes of the gauge block (623) in the center of the gauge block (623), then the dimension L of the gauge block (623) is indicated 5 Dimension L to a second tubular datum (612) 4 Equal, the distance between the two zero-order black fringes indicates that there is a difference between their dimensions, the integer fringe fraction of their difference is determined with the zero-order black fringes, the fractional part of the interference fringes is measured with monochromatic light, the total number of fringes of the pitch multiplied by half the wavelength of the monochromatic light + the correction value of the second tubular reference (612) and the other correction values of the 1-etc. gauge are of their dimensions.
5. A method for phase shifting a tubular reference illumination system, characterized in that a phase shifting process is performed using a fei-cable interferometer with a tubular reference illumination system according to any of the claims 1-3.
6. A method for a tubular reference illumination system for phase shifting techniques as recited in claim 5, wherein: the specific steps for verifying the flatness of the standard flat crystals and the checked flat crystals are as follows,
s1, mounting a standard flat crystal on a first mounting frame, mounting a detected flat crystal on a second mounting frame, and arranging relevant scribing lines on the standard flat crystal, the detected flat crystal and the two mounting frames, so that when the device is convenient to mount, the sections to be measured are mutually aligned;
s2, the light source (200) adopts white light and monochromatic light to illuminate simultaneously, when L 5 And L is equal to 4 When the difference between the two is smaller than the interference power of monochromatic light, a group of monochromatic interference fringes can be observed, and the L is gradually adjusted by using an adjusting support (319) 5 Thus, the monochromatic light interference fringes are gradually darker and clearer, when L 5 And L is equal to 4 The difference between the two interference fringes is less than 3 μm, a group of white light zero-order interference fringes suddenly appear in the monochromatic light field, the white light interference fringes are adjusted to the center of the field, the monochromatic light source is turned off, and the interference fringe direction is adjusted to the cross section to be detectedThe directions are parallel, the black zero-order interference fringes pass through the center diameter, the interference fringes are simultaneously widened, the width of the interference fringes is adjusted to be extremely wide, a field of view is provided with a piece of color to prepare for phase shifting treatment, white light is turned off, monochromatic light is turned on, and phase shifting photographing is carried out;
S3, when the width of the interference fringe is adjusted to be extremely wide, the interference fringe passes through the CCD device(307)Taking a first picture of the interference field and reading the illumination Z of the desired points 1i The air pressure in the reference main body is pressurized or depressurized through the air pump, the air pressure change in the tubular reference main body is measured through the digital micro-pressure meter, the micro-pressure meter is firstly subjected to constant degree before the instrument is used, the change quantity of the digital micro-pressure meter when one interference fringe is changed is determined, the air refractive index of the air in the tubular reference main body is further changed through the air pump changing the air pressure in the tubular reference main body, the wavelength with the optical path difference of one fourth is further increased or reduced, the wavelength is calculated to be one eighth wavelength according to the length, the second photographing is performed at the moment, and the illumination Z of each point required by a photo formed by the second photographing is read 2i Sequentially increasing or decreasing the path difference twice, increasing or decreasing the path difference by one quarter wavelength each time, and reading the illumination Z of each point 3i And Z 4i By means of
A value;
wherein: z is Z 1i ＝A i +Biconθ i ，Z 2i ＝A i +Bicon(θ i +90°)，Z 3i ＝A i +B i con(θ i +180°)，Z 4 i＝A i +B i con(θ i +270°), and Z 1 i、Z 2 i、Z 3i 、Z 4i The illumination of the photo at the point i is a fourth-order difference and a is a quarter wavelength difference i B is the background illuminance at point i i For maximum illumination of interference fringes at point i, the interference phase angle of the photo at point i is θ i Metering in degrees;
s4, two planesThe sum of the flatness of the i-point of the crystal is P i ，P i ＝θ i Lambda/720, where P i And lambda is in μm.
7. A method for a tubular reference lighting system for phase shifting techniques according to claim 6, characterized in that: when the Fizeau interferometer body (1) is a vertical interferometer, three standard flat crystals are sequentially detected by using a uniform supporting mode according to steps S1-S4, the flatness deviation of the standard flat crystals is corrected, and then the average value of three measurement and detection is taken as the final result of the flatness deviation of the standard flat crystals;
when the number of the reference flat crystals is two, each reference flat crystal is sequentially detected according to the steps S1-S4, each reference flat crystal needs to be detected twice, and the first time is that each point of the X-axis section of the reference flat crystal is aligned with each point of the X-axis section of the reference flat crystal, and the reference flat crystal is used for X i ,y i The flatness deviation of the point is corrected to obtain the standard flat crystal x to be detected i ,-y i The flatness deviation of the points, the second time is that the reference flat crystal is rotated 180 degrees, the points of the Y-axis cross sections of the standard flat crystal and the reference flat crystal are aligned, and the reference flat crystal is used for x i ,y i The flatness deviation of the point is corrected to obtain the standard flat crystal-x to be detected i ,y i Taking the average value of four verification results as the final result of the standard flat crystal flatness deviation;
When the Fizeau interferometer body (1) is a horizontal interferometer, four reference flat crystals can be obtained through four flat crystals mutual inspection of the flat crystals carried by the interferometer, the standard flat crystal is set to be flat crystal D, the reference flat crystals comprise flat crystal A, flat crystal B and flat crystal C, related scribing lines are arranged on the flat crystal A, flat crystal B, flat crystal C and flat crystal D and two mounting frames, when the installation is convenient, the sections to be measured are aligned with each other, the flat crystal D and the flatness deviation of the other three flat crystals are mutually inspected through a four-side method, the steps are as follows,
k1, placing an flat crystal B on a first bracket, placing an flat crystal A on a second bracket, aligning the coordinates of each point on the Y-axis sections of the flat crystal A and the flat crystal B one by one, wherein each point on the X-axis section direction of the flat crystal A and the flat crystal B is symmetrical with each point on the X-axis direction of the flat crystal B by an X coordinate 0 point, aligning the coordinates of each point on the X-axis direction of the flat crystal A and the flat crystal B with the coordinates of four end points of the Y-axis section, adjusting an interference field to a measurement state, measuring the sum of flatness deviations of the flat crystal A and the flat crystal B of each point on the X-axis section and the Y-axis section, setting ideal planes to pass through two end points of the Y-axis section and be parallel with two end points of the X-axis section, and obtaining a mathematical relation formula Pz1=B0, y+A0, and a mathematical relation of the Y-axis section and the X-axis section being Ps-0+A when the two flat crystal ideal planes are overlapped;
K2, taking down the flat crystal B, replacing the flat crystal C, aligning coordinates of each point on the Y-axis section of the flat crystal A and the flat crystal C one by one, and measuring in the same way as the step K1, wherein the mathematical relation of the sum of the planeness of each point on the Y-axis section of the flat crystal A and the flat crystal C is P z2 ＝C 0,y +A 0,y And the mathematical relation of the sum of the flatness of each point of the X-axis cross section is P s2 ＝C x,0 +A -x,0 ；
K3, taking down the flat crystal A, replacing the flat crystal B, aligning coordinates of each point on the Y-axis section on the flat crystal C and the flat crystal B one by one, and measuring in the same way as the step K1, wherein the mathematical relation of the sum of the planeness of each point on the Y-axis section on the flat crystal A and the flat crystal B is P z4 ＝C 0,y +B 0,y The flat crystal B is turned by 180 degrees to measure the sum of the planeness of each point of the X-axis cross section, and the mathematical relation of the sum of the planeness of each point of the X-axis cross section is obtained as P s4 ＝C x,0 +B x,0 ；
K4, taking down the flat crystal C, replacing the flat crystal D, aligning coordinates of each point on the X-axis cross section of the flat crystal B and the flat crystal D one by one, and measuring in the same way as the step K1, wherein the mathematical relation of the sum of the planeness of each point on the X-axis cross section of the flat crystal C and the flat crystal D is P s5 ＝D x,0 +B x,0 Turning the flat crystal B into 180 degrees, measuring the sum of the planeness of each point of the Y-axis cross section, and obtaining the mathematical relation of the sum of the planeness of each point of the Y-axis cross section as P z5 ＝D 0,y +B 0,y ；
K5, taking down the flat crystal B, replacing the flat crystal C, aligning coordinates of each point on the Y-axis section of the flat crystal D and the flat crystal C one by one, and measuring in the same way as the step K1, wherein the mathematical relation formula of the sum of the planeness of each point on the Y-axis section of the flat crystal D and the flat crystal C is P z6 ＝D 0,y +C 0,y The flat crystal C is turned to 180 degrees, the sum of the planeness of each point of the X-axis cross section is measured, and the mathematical relation of the sum of the planeness of each point of the X-axis cross section is obtained as P s6 ＝D x,0 +C x,0 ；
K6, taking down the flat crystal C, replacing the flat crystal A, aligning coordinates of each point on the Y-axis section of the flat crystal D and the flat crystal A one by one, and measuring in the same way as the step K1, wherein the mathematical relation formula of the sum of the planeness of each point on the X-axis section is P s3 ＝D x,0 +A -x,0 The mathematical relation of the sum of the planeness of each point of the Y-axis section is P z3 ＝D 0,y +A 0,y ；
K7, calculating the flatness of each point X on the X-axis cross sections of the flat crystals B, C and D, calculating the flatness of each point-X on the X-axis cross sections of the flat crystals A, and substituting the sum of the flatness of each point X on the X-axis cross sections of the flat crystals A, B, C and D into P z1 ＝B 0,y +A 0,y ，P z2 ＝C 0,y +A 0,y ，P z4 ＝C 0,y +B 0,y ，P z5 ＝D 0,y +B 0,y ，P z6 ＝D 0,y +C 0,y ，P z3 ＝D 0,y +A 0,y The formula A can be obtained 0,y ＝[2(P z1 +P z2 +P z3 )-((P z4 +P z5 +P z6 )]/6，B 0,y ＝[2(P z1 +P z4 +P z5 )-((P z2 +P z3 +P z6 )]/6，C 0,y ＝[2(P z2 +P z4 +P z6 )-((P z1 +P z3 +P z5 )]/6，
D 0,y ＝[2(P z3 +P z5 +P z6 )-((P z1 +P z2 +P z4 )]And/6, solving to obtain the flatness deviation of each point of the Y-axis cross sections of the flat crystals A, B, C and D, and obtaining the flat crystals A, B, C and DX of (2)The sum of the planeness of each point of the axial section is substituted into P s1 ＝B x,0 +A -x,0 ，P s2 ＝C x,0 +A -x,0 ，P s4 ＝C x,0 +B x,0 ，P s5 ＝D x,0 +B x,0 ，P s6 ＝D x,0 +C x,0 ，P s3 ＝D x,0 +A -x,0 The formula A can be obtained -x,0 ＝[2(P s1 +P s2 +P s3 )-((P s4 +P s5 +P s6 )]/6，
B x,0 ＝[2(P s1 +P s4 +P s5 )-((P s2 +P s3 +P s6 )]/6，C x,0 ＝[2(P s2 +P s4 +P s6 )-((P s1 +P s3 +P s5 )]/6，
D x,0 ＝[2(P s3 +P s5 +P s6 )-((P s1 +P s2 +P s4 )]And (6) calculating the flatness deviation of each point of the X-axis cross sections of the flat crystals A, B, C and D.
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