A device and method for multi-angle rapid adjustment of optical elements

Abstract

The application discloses a device for quickly adjusting an optical element at multiple angles, which comprises a laser interferometer, an interferometer standard lens, a zero compensation mirror and a first adjusting mechanism; a rotating turntable is installed on the first adjusting mechanism, a second adjusting mechanism is installed on the rotating turntable, a third adjusting and detecting support platform is further installed on the second adjusting mechanism, and a detected optical element is arranged on the third adjusting and detecting support platform; the adjusting amount of each adjusting mechanism can be quickly calculated through a sensitivity matrix, so that the spatial position of each adjusting mechanism and the detected optical element can be quickly adjusted, the adjusting time is greatly saved, the adjusting difficulty is reduced, and the adjustment precision is higher through the coefficients of Zernike second, third, seventh and eighth items.

Description

[0001] The present application relates to the field of optical interferometry, and in particular to a device and method for multi-angle rapid adjustment of an optical element.

[0002] With the development of modern social needs, the requirements for the surface accuracy of optical elements are becoming higher and higher, especially in photolithography lenses, the RMS value of the surface of the optical element is required to reach nanometer or even deep sub-nanometer level, which is a great challenge to optical detection.

[0003] The rotation-translation absolute detection method is a commonly used absolute calibration method for improving the accuracy of optical detection. In 1999, Nikon Corporation of Japan reported the principle and experimental device of optical spherical surface absolute detection based on rotation-translation. In 2001, Carl Zeiss Company of Germany used this technology to realize the absolute detection of optical spherical surface on a self-made Fizeau interferometer, and the detection accuracy reached 0.15nm RMS (Bernd D, Gunther S, Interferometric testing of optical surfaces at its current limit[J], Optik, 2001, 112(9):392-398). Compared with the double-spherical surface absolute detection method, the rotation-translation method does not need to accurately determine the position of the cat-eye, and can reflect the advantages of short interference cavity when detecting convex spherical surface, and this method can be used for absolute detection of plane, and has strong versatility.

[0004] When detecting an optical element by using the rotation-translation absolute detection method, the spatial position of the optical element needs to be adjusted multiple times to make the optical axis of the interferometer and the optical axis of the optical element consistent. For coaxial aspheric surfaces, although the rotation-translation method cannot be used to detect the absolute surface, the multi-angle rotation method can be used to calibrate the rotation asymmetry error. Although the multi-angle rotation method does not require translation, the spatial position requirement of the detected optical element is higher than that of the rotation-translation absolute detection of the plane spherical surface, which greatly increases the detection adjustment time and also increases the adjustment difficulty, making the detection adjustment process complicated, and the adjustment accuracy cannot meet the expected effect.

[0005] The purpose of the present application is to provide a device for multi-angle rapid adjustment of an optical element,

[0006] The device comprises a laser interferometer, an interferometer standard lens, a zero compensation mirror and a first adjustment mechanism.

[0007] ​​​The first adjusting mechanism is provided with a rotating turntable, the rotating turntable is provided with a second adjusting mechanism, and the second adjusting mechanism is further provided with a third adjusting and detecting support platform.

[0008] Preferably, the laser interferometer, the interferometer standard lens, and the zero compensation mirror are arranged in a line perpendicular to the first adjusting mechanism.

[0009] In order to achieve the above purpose, a method for quickly adjusting an optical element at multiple angles comprises the following steps:

[0010] S1: adjusting the optical element by using the third adjusting mechanism and the first adjusting mechanism, so that the light spot on the interferometer monitor does not move when the rotating turntable is rotated;

[0011] S2: establishing a sensitivity matrix of the first adjusting mechanism and the second adjusting mechanism with respect to Zernike terms 2 and 3 (XY direction tilt) and coma terms 7 and 8;

[0012] S3: detecting the optical element by using the interferometer, and recording original tilt and coma terms 1, 2, 7 and 8 at this time;

[0013] S4: rotating the turntable by 180°, and detecting the optical element again, and recording the tilt and coma terms 1, 2, 7 and 8 after rotation at this time;

[0014] S5: calculating the adjustment amount by using the sensitivity matrix and adjusting the optical element by using the second adjusting mechanism, and calculating the values of terms 1, 2, 7 and 8;

[0015] S6: repeating S3 to S5 until the terms 1, 2, 7 and 8 are unchanged when the turntable is rotated;

[0016] S7: adjusting the terms 1, 2, 7 and 8 to zero by using the first adjusting mechanism, and the spatial positions of the optical axis of the interferometer, the optical axis of the optical element, the rotating shaft of the turntable, and the central axis of the first adjusting mechanism are consistent, and the optical element is adjusted to the position.

[0017] Preferably, the sensitivity matrix in S2 is established by respectively adjusting the XY direction translation and tilt by a certain amount, and the sensitivity matrix is obtained by subtracting the terms 1, 2, 7 and 8 before and after adjustment.

[0018] The device and method for multi-angle fast adjustment of optical elements provided by the application have the following beneficial effects: for absolute detection, especially non-spherical absolute detection, the adjustment of the spatial positions of the center axes of the detected optical elements and the adjustment mechanisms is often difficult, time-consuming, complicated and the adjustment precision cannot meet the expected effect. Therefore, the adjustment amount of each adjustment mechanism can be quickly calculated by the sensitivity matrix, so as to quickly adjust the spatial positions of each adjustment mechanism and the detected optical element, greatly saving the adjustment time and reducing the adjustment difficulty. By comparing the coefficients of Zernike 2, 3, 7 and 8, the adjustment precision is higher. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0020] Figure 1 The device for multi-angle fast adjustment of optical elements provided by the embodiment of the application is shown in the figure.

[0021] Figure 2 The step diagram for multi-angle fast adjustment of optical elements provided by the embodiment of the application is shown in the figure.

[0022] 1. First adjustment mechanism, 2. Turntable, 3. Second adjustment mechanism, 4. Third adjustment mechanism and detection support platform, 5. Detected optical element, 6. Zero compensation mirror, 7. Interferometer standard lens, 8. Laser interferometer. DETAILED DESCRIPTION

[0023] In order to make those skilled in the art better understand the application scheme, the technical solutions in the embodiments of the application will be described clearly and completely in conjunction with the drawings in the embodiments of the application. Obviously, the described embodiments are only some embodiments of the application, not all. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor should be within the scope of protection of the application.

[0024] It should be noted that the terms "first", "second", and the like in the description and in the claims of the present application and the above-described accompanying drawings are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the application described herein can also be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0025] The embodiments of the present application will be further described in detail below with reference to the accompanying drawings, such as Figure 1 The device for adjusting optical elements at multiple angles provided by the present application is shown in the figure, which comprises a laser interferometer, an interferometer standard lens, a zero compensation mirror and a first adjusting mechanism.

[0026] The first adjusting mechanism is provided with a rotating turntable, the rotating turntable is provided with a second adjusting mechanism, and the second adjusting mechanism is further provided with a third adjusting and detecting support platform, and the detected optical element is placed on the third adjusting and detecting support platform.

[0027] The laser interferometer, the interferometer standard lens, the zero compensation mirror and the first adjusting mechanism are arranged vertically along a line.

[0028] The method for adjusting optical elements at multiple angles provided by the embodiments of the present application is shown in the figure, Figure 2

[0029] The method comprises the following steps:

[0030] S1: adjusting the detected optical element by using the third adjusting mechanism and the first adjusting mechanism, so that the light spot on the interferometer monitor does not move when the rotating turntable is rotated;

[0031] S2: establishing the sensitivity matrix M of Zernike about Z2, Z3 (XY direction tilt) and Z7, Z8 coma term coefficients of the first adjusting mechanism and the second adjusting mechanism;

[0032] Among them, the sensitivity matrix M is established by respectively adjusting the XY direction translation and tilt by a certain amount, and then subtracting the Z2, Z3, Z7, Z8 term coefficients before and after the adjustment to obtain the sensitivity matrix.

[0033] ​Specifically, whether the adjustment mechanism, the optical axis of the interferometer and the optical axis of the inspected optical element are accurately coincident is usually judged by Zernike coefficients, and the sensitivity matrix is obtained by subtracting the Zernike coefficients of the second, third, seventh and eighth terms of the initial position from the Zernike coefficients of each detection result after the first and second adjustment mechanisms are translated and tilted to detect the inspected optical element, and the movement amount of the last detection needs to be restored when the next detection is performed during the process of establishing the sensitivity matrix.

[0034] S3: detecting the inspected optical element by using the interferometer, and recording the original tilt and coma term coefficients (Z2(1), Z3(1), Z7(1), Z8(1)) at this time;

[0035] S4: rotating the rotary table by 180°, and detecting the inspected optical element again, and recording the tilt and coma term coefficients (Z2(2), Z3(2), Z7(2), Z8(2)) at this time;

[0036] S5: calculating the adjustment amount by using the sensitivity matrix and adjusting the inspected optical element by using the second adjustment mechanism, and adjusting the values of Z2, Z3, Z7 and Z8 to ((Z2(1)+Z2(2)) / 2, (Z3(1)+Z3(2)) / 2, (Z7(1)+Z7(2)) / 2, (Z8(1)+Z8(2)) / 2), and the adjustment amounts δX, δY, δRX and δRY can be calculated by the following formula;

[0037]

[0038] S6: repeating S3 to S5 until the Z2, Z3, Z7 and Z8 coefficients are unchanged when the rotary table is rotated;

[0039] S7: adjusting the Z2, Z3, Z7 and Z8 coefficients to zero by using the first adjustment mechanism. At this time, the spatial positions of the optical axis of the interferometer, the optical axis of the inspected optical element, the rotary shaft of the rotary table and the central axis of the first adjustment mechanism are consistent, and the inspected optical element is adjusted to the position.

[0040] Specifically, S3 to S7 can first adjust the interference fringes at zero degrees to zero fringes, and then observe the interference fringes by rotating the aspheric surface through the rotary table by 180°, and adjust each adjustment mechanism by iteration to make the interference fringes at zero fringes when the rotary table is rotated by 180° without adjusting any adjustment mechanism.

[0041] The above-mentioned embodiment numbers of the present application are only for description, and do not represent the advantages and disadvantages of the embodiments.

[0042] In the above-mentioned embodiments of the present application, the description of each embodiment has its own emphasis, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0043] In summary, the device and method for quickly adjusting a multi-angle optical element provided by the present application have the following advantages: for absolute detection, especially non-spherical absolute detection, the adjustment of the spatial positions of the center axes of the detected optical element and each adjustment mechanism is difficult, time-consuming and complicated, and the adjustment accuracy cannot meet the expected effect. Therefore, the present method can quickly calculate the adjustment amount of each adjustment mechanism through the sensitivity matrix, thereby quickly adjusting the spatial positions of each adjustment mechanism and the detected optical element, greatly saving the adjustment time, reducing the adjustment difficulty, and improving the adjustment accuracy by comparing the coefficients of the second, third, seventh and eighth Zernike terms.

[0044] In several embodiments provided in the present application, it should be understood that the disclosed technical contents can be implemented in other ways. Among them, the above-described device embodiments are only schematic, for example, the division of units can be a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed, in addition, the coupling or direct coupling or communication connection between the units or modules shown or discussed can be through some interfaces, indirect coupling or communication connection between units or modules, which can be electrical or other forms.

[0045] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, that is, they can be located in one place or distributed on multiple units. According to actual needs, some or all of the units can be selected to achieve the purpose of the present embodiment.

[0046] In addition, each functional unit in each embodiment of the present application can be integrated into a processing unit, or each unit can exist physically, or two or more units can be integrated into one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0047] The integrated unit, if implemented in the form of a software function unit and sold or used as an independent product, can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application or the entire or part of the technical solutions that essentially contribute to the prior art can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server or a network device, etc.) to execute all or part of the steps of the embodiments of the present application. The aforementioned storage medium includes a U disk, a read-only memory (ROM), a random access memory (RAM), a mobile hard disk, a magnetic disk or an optical disk, and various media that can store program codes.

[0048] The above is only the preferred embodiment of the present application, and does not limit the present application in any way. Any person skilled in the art can make any form of equivalent replacement, modification or change to the technical solutions and technical contents disclosed by the present application without departing from the scope of the technical solutions of the present application, and still falls within the protection scope of the present application.

Claims

1. A method for rapidly adjusting an optical element from multiple angles, characterized in that, A device including a multi-angle rapid adjustment optical element, the device comprising a laser interferometer, an interferometer standard lens, a null compensation mirror, and a first adjustment mechanism; The first adjustment mechanism is equipped with a rotary table, and the rotary table is equipped with a second adjustment mechanism. The second adjustment mechanism is further equipped with a third adjustment and testing support platform, on which the optical element under test is placed; the method includes the following steps: S1: The optical element under test is adjusted using the third adjustment mechanism and the first adjustment mechanism so that the light spot on the interferometer monitor remains stationary when the rotary table is rotated. S2: Establish the sensitivity matrices of the first and second adjustment mechanisms with respect to the coefficients of the second, third, seventh, and eighth coma terms of the Zernike system; S3: Use an interferometer to test the optical element under test, and record the original tilt and coma coefficients of the second, third, seventh and eighth terms at this time; S4: Rotate the turntable 180° and test the optical element under test again. Record the tilt and coma coefficients of the first, second, seventh and eighth terms after the rotation. S5: Calculate the adjustment amount using the sensitivity matrix and adjust the tested optical element through the second adjustment mechanism to calculate the values ​​of the first, second, seventh, and eighth items; S6: Repeat S3 to S5 until the coefficients of the first, second, seventh, and eighth terms remain unchanged when the turntable is rotated; S7: Using the first adjustment mechanism, the coefficients of the first, second, seventh, and eighth items are adjusted to zero. At this time, the spatial positions of the interferometer optical axis, the optical axis of the optical element under test, the turntable rotation axis, and the central axis of the first adjustment mechanism are consistent, and the optical element under test is adjusted into place.

2. The method for rapidly adjusting an optical element at multiple angles according to claim 1, characterized in that... The sensitivity matrix in S2 is established by adjusting the translation and tilt in the XY directions by a certain amount, and then subtracting the coefficients of the first, second, seventh, and eighth terms before and after the adjustment to obtain the sensitivity matrix.

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