Off-axis three-mirror optical system assembling and adjusting methodTechnical Field
The invention belongs to the technical field of off-axis reflection imaging optical systems, and particularly relates to a general design and adjustment method of an off-axis three-mirror optical system.
Background
The off-axis three-mirror imaging optical system is an important component of a space remote sensing measurement system, but due to the characteristics that the off-axis three-mirror imaging optical system has high utilization rate of convex high-order aspheric lenses, each lens is relatively independent and has large span, and the adjustable freedom of each lens space is high, when the off-axis three-mirror imaging optical system is assembled and adjusted, the phenomena that the relatively accurate position of each lens is difficult to determine, the lens space posture is difficult to accurately adjust, the lens space posture is discontinuous, and the like occur.
Disclosure of Invention
In view of the above disadvantages, the present invention provides a method for designing an overall off-axis three-mirror optical system, which includes a primary mirror, a secondary mirror, a first mirror, a second mirror, a dichroic filter, a first plane mirror, and a second plane mirror, wherein non-reflective surfaces of the primary mirror, the secondary mirror, the first mirror, and the second mirror are processed into polished surfaces, the secondary mirror is placed in a positioning frame of the secondary mirror, the other lenses are arranged in respective positioning adjusting devices, the mounting surface of the positioning adjusting device of the main mirror is selected as a reference plane, determining the positions of the mounting surface of the positioning frame of the secondary mirror and the mounting surfaces of the positioning adjusting devices of the other lenses except the primary mirror according to the height difference between the mounting surface of the positioning frame of the secondary mirror and the mounting surfaces of the positioning adjusting devices of the other lenses except the primary mirror and the reference plane, and secondarily processing the mounting surface of the positioning frame of the secondary mirror and the mounting surfaces of the positioning adjusting devices of the other lenses to ensure the mounting accuracy; and taking the projection point of the intersection point of the reflection or transmission surface of each lens and the central line of the lens on the corresponding mounting surface as the center of the positioning hole of each lens, and secondarily machining the positioning frame mounting surface positioning hole of the secondary lens and the mounting surface positioning holes of the other lens positioning adjusting devices to ensure the positioning accuracy so as to mount the positioning frame of the secondary lens and the other lens positioning adjusting devices.
Preferably, the positioning and adjusting device comprises a mirror frame and a flange seat with a support, a first fine adjustment knob is arranged below the mirror frame, the mirror frame is suspended on the flange seat, the mirror frame can deflect within +/-3 degrees through the first fine adjustment knob, and the deflection axis of the mirror frame passes through the intersection point of the reflection or transmission surface of a lens in the mirror frame and the central line of the lens; the center of the bottom surface of the flange seat is provided with a positioning column, the side surface of the flange seat is provided with a fine adjustment mechanism consisting of a worm wheel and a worm, the flange seat can deflect within +/-3 degrees through a second fine adjustment knob at the end part of the worm, and the projection of the intersection point of the reflection or transmission surface of the lens in the lens frame and the central line of the lens on the bottom surface of the flange seat is superposed with the center of the bottom surface of the flange seat.
As another aspect of the present invention, the present invention provides an adjusting method of an off-axis three-mirror optical system, including the following steps:
step 1, determining a reference optical axis and theoretical positions of a primary mirror, a secondary mirror and a second reflecting mirror;
respectively placing a reference theodolite and an internal focusing telescope on two sides of a primary mirror and a secondary mirror for auto-collimation and cross-collimation, and ensuring that the optical axes of the reference theodolite and the internal focusing telescope are collinear and determined as a reference optical axis; keeping the states of the reference theodolite and the internal focusing telescope unchanged, respectively placing a positioning adjusting device of the primary mirror and a positioning frame of the secondary mirror, rotating and heightening the positioning frame of the secondary mirror to enable the reference theodolite to finish auto-collimation through the secondary mirror, adjusting the positioning adjusting device of the primary mirror to enable the internal focusing telescope to finish auto-collimation through the primary mirror, and realizing the coaxiality of the primary mirror and the secondary mirror, wherein the positions of the primary mirror and the secondary mirror are the theoretical positions of the primary mirror and the secondary mirror; a positioning adjusting device of a second reflector is arranged between the primary mirror and the inner focusing telescope, the pitching and azimuth angles of the inner focusing telescope are kept unchanged, the inner focusing telescope is translated by 1.4mm perpendicular to a reference optical axis, the positioning adjusting device of the second reflector is adjusted to enable the inner focusing telescope to finish auto-collimation, and at the moment, the position of the second reflector is the theoretical position of the second reflector, and meanwhile, the state of the reference theodolite is kept unchanged;
step 2, determining the theoretical position of the color separation sheet;
a first theodolite is arranged on one side of the reflecting surface of the color separation sheet, the height of the optical axis of the first theodolite is consistent with that of the optical axis of the reference theodolite, and the reference theodolite and the first theodolite are deflected by a certain angle respectivelyCarrying out auto-collimation and mutual collimation, recording the deflection angle alpha of the reference theodolite during mutual collimation, and leading the first theodolite to deflect the angle alpha again1In which α is1The optical axis of the first warp-weft instrument and the optical axis of the theoretical position of the color separation sheet form an included angle of 45 degrees; adjusting a positioning adjusting device of the color separation sheet to change the position state of the color separation sheet, so that the first theodolite completes auto-collimation through the color separation sheet, the position of the color separation sheet at the moment is the theoretical position of the color separation sheet, and meanwhile, the reference theodolite is restored to the pre-deflection state;
step 3, determining the theoretical position of the first reflector;
placing a second theodolite on one side of the non-reflecting surface of the first reflector, ensuring that the optical axis of the second theodolite is consistent with the optical axis of the reference theodolite in height, respectively deflecting the reference theodolite and the second theodolite by a certain angle, then performing auto-collimation and cross-collimation, recording the deflection angle beta of the reference theodolite during cross-collimation, and making the second theodolite deflect the angle beta again1In which beta is1The optical axis of the second theodolite is coincided with the optical axis of the theoretical position of the first reflector; adjusting a positioning adjusting device of the first reflector to change the position state of the first reflector, so that the second theodolite performs auto-collimation through the first reflector, and the position of the first reflector at the moment is the theoretical position of the first reflector, and meanwhile, the reference theodolite is restored to the pre-deflection state;
step 4, determining the theoretical position of the first plane mirror;
put a third theodolite, a fourth theodolite and a fifth longitude latitude respectively, guarantee that the optical axis of third theodolite, fourth theodolite and fifth longitude latitude all is unanimous with the optical axis height of benchmark theodolite, third theodolite and benchmark theodolite homonymy set up, fifth theodolite and the setting of interior focusing telescope homonymy, fourth theodolite is located one side of the non-plane of first speculum, make benchmark theodolite counter-clockwise turning 90, make third theodolite and benchmark theodolite carry out the counter-clockwise turning 90 after the auto-collimation is aimed each other, carry out the auto-collimation with fifth longitude latitude again and aim each other, then the horizontal light path that third theodolite and fifth longitude latitude constitute is on a parallel with the benchmark optical axis, the theoretical light path of first plane mirror is on a parallel with the benchmark optical axisThe position is on the horizontal light path; simultaneously restoring the reference theodolite to a pre-deflection state; respectively deflecting the fifth theodolite and the fourth theodolite by a certain angle, then carrying out auto-collimation cross-sight, recording the deflection angle gamma of the fifth theodolite during cross-sight, and then deflecting the angle gamma again by the fourth theodolite1Wherein γ is1The optical axis of the fourth theodolite is made to coincide with the optical axis of the theoretical position of the first plane mirror by 180-40.8-gamma; adjusting a positioning adjusting device of the first plane mirror to change the position state of the first plane mirror, so that the fourth theodolite completes auto-collimation, the position of the first plane mirror at the moment is the theoretical position of the first plane mirror, and meanwhile, the state of the fifth theodolite when the optical axis is parallel to the optical axis of the reference theodolite is recovered;
step 5, determining the theoretical position of the second plane mirror;
a sixth warp and weft instrument is arranged on one side of the reflecting surface of the second plane mirror, and the height of the optical axis of the sixth warp and weft instrument is ensured to be consistent with that of the optical axis of the reference theodolite; and rotating the fifth longitude and latitude instrument by 90 degrees anticlockwise, performing auto-collimation cross-aiming on the fifth longitude and latitude instrument and the sixth longitude and latitude instrument, deflecting the sixth longitude and latitude instrument by an angle delta again, wherein the delta is 180-38.88-90 degrees, enabling the optical axis of the sixth longitude and latitude instrument to be coincided with the optical axis of the theoretical position of the second plane mirror, adjusting a positioning adjusting device of the second plane mirror to change the position state of the second plane mirror, enabling the sixth longitude and latitude instrument to complete auto-collimation, and enabling the position of the second plane mirror at the moment to be the theoretical position of the second plane mirror.
The present invention also includes other devices, components or steps that enable the general design and setup of the off-axis three-mirror optical system to be used as is conventional in the art. In addition, means, components or steps that are not limited in this invention are taken to be conventional in the art.
The invention has the advantages that the micro adjustment of each lens in the off-axis three-mirror optical system is realized through the positioning adjusting device, and the adjusting difficulty is reduced; the precision of the mounting surface and the positioning hole of the positioning adjusting device is ensured through secondary processing, and the relative precise position of each lens is favorably determined; the lenses are placed in the positioning adjusting device, so that the multi-degree-of-freedom adjustment and positioning of the lenses in the space are realized, and the debugging of the off-axis three-mirror optical system is facilitated; the off-axis three-mirror optical system is simpler to adjust and more convenient to install and adjust.
Drawings
The invention is further illustrated with reference to the following figures and examples.
FIG. 1 is a schematic diagram of an optical system of the present invention;
FIG. 2 is a schematic diagram of the overall design structure of the present invention;
FIG. 3 is a schematic view of the structure of the mounting surface of the positioning adjustment device for all the lenses in the present invention;
FIG. 4 is a schematic view of a single positioning adjustment device of the present invention;
fig. 5 is a schematic view of the arrangement of the components in the adjustment method of the present invention.
Detailed Description
The present invention will be described more clearly with reference to the accompanying drawings, which are included to illustrate and not to limit the present invention. All other embodiments, which can be obtained by those skilled in the art without any inventive step based on the embodiments of the present invention, should be included in the scope of the present invention.
Example 1
As shown in fig. 1 to 4, the present invention provides a method for designing an overall off-axis three-mirror optical system, which includes a primary mirror 1, asecondary mirror 2, a first reflectingmirror 3, a second reflectingmirror 4, adichroic filter 7, afirst plane mirror 5 and asecond plane mirror 6, wherein non-reflecting surfaces of the primary mirror 1, thesecondary mirror 2, the first reflectingmirror 4 and the second reflectingmirror 4 are processed into polished surfaces, thesecondary mirror 2 is placed in a positioning frame of the secondary mirror, so that the other lenses are placed in respective positioning adjustment devices, an installation surface of the positioning adjustment device of the primary mirror 1 is selected as areference plane 13, and positions of an installation surface of the positioning frame of thesecondary mirror 2 andinstallation surfaces 14 of the positioning adjustment devices of the other lenses except the primary mirror 1 are determined according to a height difference between the installation surface of the positioning frame of thesecondary mirror 2 and thereference plane 13 and theinstallation surfaces 14 of the positioning adjustment devices of the other lenses except the primary mirror 1, the mounting surface of the positioning frame of thesecondary mirror 2 and the mounting surfaces of the positioning adjusting devices of the other lenses are machined for the second time to ensure the mounting precision; and taking the projection point of the intersection point of the reflection or transmission surface of each lens and the central line of the lens on the corresponding mounting surface as the center of thepositioning hole 8 of each lens, and secondarily processing the mounting surface positioning hole of the positioning frame of thesecondary mirror 2 and the mountingsurface positioning holes 8 of the other lens positioning adjusting devices to ensure the positioning precision so as to mount the positioning frame of thesecondary mirror 2 and the other lens positioning adjusting devices.
The positioning adjusting device comprises amirror frame 16 and aflange seat 18 with a support, a firstfine adjustment knob 17 is arranged below themirror frame 16, themirror frame 16 is suspended on theflange seat 18, themirror frame 16 can deflect within +/-3 degrees through the firstfine adjustment knob 17, and the deflection axis of the deflection knob passes through the intersection point of the reflection or transmission surface of a lens in themirror frame 16 and the central line of the lens; the center of the bottom surface of theflange seat 18 is provided with apositioning column 19, the side surface of the flange seat is provided with a fine adjustment mechanism consisting of aworm wheel 20 and aworm 22, theflange seat 18 can deflect within +/-3 degrees through a secondfine adjustment knob 21 at the end part of the worm, and the projection of the intersection point of the reflection or transmission surface of the lens in thelens frame 16 and the central line of the lens on the bottom surface of theflange seat 18 is superposed with the center of the bottom surface of theflange seat 18.
Example 2
As shown in fig. 5, the present invention provides an adjusting method of an off-axis three-mirror optical system, comprising the following steps:
step 1, determining a reference optical axis and theoretical positions of a primary mirror 1, asecondary mirror 2 and a second reflectingmirror 4;
respectively placing areference theodolite 23 and an internal focusingtelescope 24 on two sides of a primary mirror 1 and asecondary mirror 2 for auto-collimation and cross-collimation, ensuring that the optical axes of thereference theodolite 23 and theinternal focusing telescope 24 are collinear and determined as a reference optical axis; keeping the states of thereference theodolite 23 and theinternal focusing telescope 24 unchanged, respectively placing a positioning adjusting device of the primary mirror 1 and a positioning frame of thesecondary mirror 2, rotating and heightening the positioning frame of thesecondary mirror 2 to enable thereference theodolite 23 to finish auto-collimation through thesecondary mirror 2, adjusting the positioning adjusting device of the primary mirror 1 to enable theinternal focusing telescope 24 to finish auto-collimation through the primary mirror 1, realizing the coaxiality of the primary mirror 1 and thesecondary mirror 2, and enabling the positions of the primary mirror 1 and thesecondary mirror 2 to be the theoretical positions of the primary mirror 1 and thesecondary mirror 2 at the moment; a positioning adjusting device of the second reflectingmirror 4 is arranged between the primary mirror 1 and the inner focusingtelescope 24, the pitching and azimuth angles of the inner focusingtelescope 24 are kept unchanged, the inner focusingtelescope 24 is translated by 1.4mm perpendicular to the reference optical axis (the distance is the designed distance between the reference optical axis in the optical path system and the horizontal optical path formed by thethird theodolite 27 and thefifth theodolite 29 in the step 4), the positioning adjusting device of the second reflectingmirror 4 is adjusted to enable the inner focusingtelescope 24 to finish self-collimation, and the position of the second reflectingmirror 4 is the theoretical position of the second reflectingmirror 4 at the moment, and meanwhile, the state of thereference theodolite 23 is kept unchanged;
step 2, determining the theoretical position of thecolor separation sheet 7;
afirst theodolite 25 is arranged on one side of the reflecting surface of thecolor separation plate 7, the optical axis of thefirst theodolite 25 is ensured to be consistent with the optical axis height of thereference theodolite 23, thereference theodolite 23 and thefirst theodolite 25 are respectively enabled to deflect a certain angle and then are subjected to auto-collimation mutual aiming, the deflection angle alpha of thereference theodolite 23 during mutual aiming is recorded, and thefirst theodolite 25 is enabled to deflect the angle alpha again1In which α is1The optical axis of thefirst theodolite 25 and the optical axis of the theoretical position of thecolor separation sheet 7 form an included angle of 45 degrees; adjusting a positioning adjusting device of thecolor separation sheet 7 to change the position state of thecolor separation sheet 7, so that thefirst theodolite 25 completes auto-collimation through thecolor separation sheet 7, the position of thecolor separation sheet 7 at the moment is the theoretical position of thecolor separation sheet 7, and meanwhile, thereference theodolite 23 is restored to the pre-deflection state;
step 3, determining the theoretical position of thefirst reflector 3;
asecond theodolite 26 is arranged on one side of the non-reflecting surface of thefirst reflector 3, the optical axis of thesecond theodolite 26 is ensured to be consistent with the optical axis height of thereference theodolite 23, thereference theodolite 23 and thesecond theodolite 26 are enabled to deflect by a certain angle respectively to carry out auto-collimation and mutual aiming, the deflection angle beta of thereference theodolite 23 during mutual aiming is recorded, and thesecond theodolite 26 is enabled to deflect by the angle beta again1In which beta is1The optical axis of thesecond theodolite 26 is made to coincide with the optical axis of the theoretical position of thefirst mirror 3, i.e. 90 ° - β; adjusting the positioning of the first mirror 3The joint device changes the position state of thefirst reflector 3, so that thesecond theodolite 26 performs auto-collimation through thefirst reflector 3, the position of thefirst reflector 3 at the moment is the theoretical position of thefirst reflector 3, and meanwhile, thereference theodolite 23 is restored to the pre-deflection state;
step 4, determining the theoretical position of thefirst plane mirror 5;
respectively placing athird theodolite 27, afourth theodolite 28 and afifth theodolite 29, ensuring that the optical axes of thethird theodolite 27, thefourth theodolite 28 and thefifth theodolite 29 are all consistent with the optical axis height of thereference theodolite 23, arranging thethird theodolite 27 and thereference theodolite 23 at the same side, arranging thefifth theodolite 29 and theinner focusing telescope 24 at the same side, positioning thefourth theodolite 28 at one side of the non-reflecting surface of thefirst reflector 3, rotating thereference theodolite 23 anticlockwise by 90 degrees, rotating thethird theodolite 27 and thereference theodolite 23 anticlockwise by 90 degrees after auto-collimation cross aiming, then performing auto-collimation cross aiming with thefifth theodolite 29, and enabling the horizontal light path formed by thethird theodolite 27 and thefifth theodolite 29 to be parallel to the reference optical axis, wherein the theoretical position of thefirst plane mirror 5 is positioned on the horizontal light path; while restoring thereference theodolite 23 to a pre-deflection state; thefifth theodolite 29 and thefourth theodolite 28 are respectively deflected by a certain angle for auto-collimation crosshair, the deflection angle gamma of thefifth theodolite 29 during crosshair is recorded, and then thefourth theodolite 28 deflects the angle gamma again1Wherein γ is1180 ° -40.8 ° - γ, wherein 40.8 ° is a design value of an angle between thefirst plane mirror 5 and the reference optical axis, such that the optical axis of thefourth theodolite 28 coincides with the optical axis of the theoretical position of thefirst plane mirror 5; adjusting the positioning adjustment device of thefirst plane mirror 5 to change the position state of thefirst plane mirror 5, so that thefourth theodolite 28 completes auto-collimation, and then the position of thefirst plane mirror 5 at the moment is the theoretical position of thefirst plane mirror 5, and simultaneously, the state when the optical axis of thefifth theodolite 29 is parallel to the optical axis of thereference theodolite 23 is recovered;
step 5, determining the theoretical position of thesecond plane mirror 6;
asixth theodolite 30 is arranged on one side of the reflecting surface of thesecond plane mirror 6, so that the height of the optical axis of thesixth theodolite 30 is consistent with that of the optical axis of thereference theodolite 23; rotating thefifth theodolite 29 by 90 degrees counterclockwise, performing auto-collimation cross-aiming on thefifth theodolite 29 and thesixth theodolite 30, and then deflecting thesixth theodolite 30 by an angle δ again, wherein δ is 180 ° -38.88 ° -90 °, wherein 38.88 ° is a design value of an included angle between thesecond plane mirror 6 and a reference optical axis, so that the optical axis of thesixth theodolite 30 coincides with the optical axis of the theoretical position of thesecond plane mirror 6, adjusting a positioning adjusting device of thesecond plane mirror 6 to change the position state of thesecond plane mirror 6, so that thesixth theodolite 30 completes auto-collimation, and then the position of thesecond plane mirror 6 at this moment is the theoretical position of thesecond plane mirror 6.
The invention realizes the micro adjustment of each lens in the off-axis three-mirror optical system through the positioning adjusting device, thereby reducing the adjusting difficulty; the precision of the mounting surface of the positioning adjusting device and thepositioning hole 8 is ensured through secondary processing, and the relative position of each lens is favorably adjusted; the lenses are placed in the positioning adjusting device, so that the multi-degree-of-freedom adjustment and positioning of the lenses in the space are realized, and the debugging of the off-axis three-mirror optical system is facilitated; the off-axis three-mirror optical system is simpler to adjust and more convenient to install and adjust.
Having described embodiments of the present invention, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the illustrated embodiments.