Surface shape detection method of larger-aperture and batched off-axis sub-mirrors
A technology of surface shape detection and batch production, which is applied in the direction of measuring devices, instruments, optical devices, etc., and can solve problems such as unspecified detection schemes
Inactive Publication Date: 2015-07-15
NANJING INST OF ASTRONOMICAL OPTICS & TECH NAT ASTRONOMICAL OBSE
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Problems solved by technology
For the surface shape detection of large-aperture and batch off-axis mirrors, the existing technology has not given a general detection scheme
Method used
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Embodiment 1
[0025] Embodiment 1, using the calculation hologram and the aplanatic single lens to jointly carry out the method for compensating the asphericity of the large-aperture, batch off-axis sub-mirror, refer to Figure 1-Figure 4 : Use an aplanatic single lens to shorten the inspection optical path and compensate most of the asphericity, and use a calculation hologram to compensate the remaining asphericity. When inspecting sub-mirrors with different off-axis quantities, you only need to replace the calculation hologram, including the following step:
[0026] Step 1: The radius of curvature of the apex of the extremely large aperture astronomical mirror is generally tens of meters. Due to the limitation of the experimental site and the influence of air disturbance, it is impossible to place an optical path with a length of tens of meters. For this purpose, an aplanatic single lens conjugated to a finite distance is designed. One side of the lens is a spherical surface, and the oth...
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A surface shape detection method of larger-aperture and batched off-axis sub-mirrors comprises steps as follows: 1, aplanatic single lens conjugated at a limited distance is designed, one surface of the lens is a spherical surface, and even terms are superposed to the other surface; 2, the off-axis sub-mirrors are horizontally moved to an optical axis of an interferometer and rotated around the peaks of the sub-mirrors; 3, a computer generated hologram piece is inserted before the aplanatic single lens for self-collimation detection; 4, carrier frequency is added on the basis of the compensation phase of the computer generated hologram piece; 5, the sub-mirrors with a certain off-axis amount are optimized and designed with optical design software; 6, processing technology parameters of the computer generated hologram piece are designed; 7, the steps are repeated, detection optical paths are designed for different off-axis sub-mirrors with different off-axis amounts, and the design content comprises the distance between a to-be-detected mirror surface and the aplanatic single lens, the phase distribution of main hologram and phase distribution of alignment hologram. All that is required is to replace the computer generated hologram piece when the sub-mirrors with different off-axis amounts are detected with the method. The computer generated hologram piece is small in aperture, high in design and processing accuracy and convenient to assemble and debug and saves the cost.
Description
technical field [0001] The invention belongs to the field of optical interferometric measurement and testing, and in particular relates to a method for interferometrically detecting the surface shape accuracy of large-diameter and batched off-axis sub-mirrors by using a calculation hologram and an aplanatic single lens. Background technique [0002] A quadratic curve is rotated around its axis of symmetry to form a quadric surface. The shape of the optical mirror of astronomical telescope is generally a quadric surface, which has rotational symmetry. If a mirror is spliced by multiple small mirrors, the final mirror is called a mother mirror, and the small mirrors are called off-axis sub-mirrors. The mother mirror is rotationally symmetric, while the off-axis sub-mirrors are no longer rotationally symmetric (except for the one in the center). [0003] In order to process an optical mirror that is consistent with the theoretical shape, it is necessary to detect the surfac...
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IPC IPC(8): G01B11/24
Inventor 徐秋云徐晨李博李新南
Owner NANJING INST OF ASTRONOMICAL OPTICS & TECH NAT ASTRONOMICAL OBSE