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As the SiC lightweight primary mirror in a 4 m photoelectric telescope has high specific stiffness and needs strict surface precision, this paper proposes an axial active support system based on the hydraulic whiffletree passive support for the primary mirror. The hydraulic whiffletree support system was used to support the mirror weight, and the active support was just output active forces to correct mirror surface errors, reduce the active force range and to increase the precision of active force. A 54-point axial support system and a 24-point lateral support system were optimized by the Finite Element Method (FEM), and the parameter of lateral force was 0.5. With the hydraulic passive support system, the mirror surface deformation Root Mean Square (RMS) values from the gravity of the primary mirror are 37.8 nm and 82.9 nm respectively under horizontal and vertical states. After active correction, the mirror surface error RMS values are reduced to 12.0 nm and 9.8 nm accordingly. Analysis indicates that the mirror surface deformation of 4 m SiC lightweight primary mirror at different pitch angles is less than /30(=632.8 nm) and meets the requirements of surface errors.

To calibrate the test instrument of a Head-Mounted Display(HMD),a standard HMD optical system with a simple configuration and ascendant optical performance is proposed.In the limited space avoilable,the optical system is designed with only a spherical surface and an on-axial scheme to meet the requirements of low distortion and high resolution.By the symmetry principle of optical design,most aberrations of the standard HMD system can be corrected synthetically.The standard HMD system is used twice so that the system has a sharp exit pupil.The standard HMD system has a designed for a 0.5 inch Cathode Ray Tube(CRT) with a field of view 30° and an exit pupil distance of 75 mm.The MTF at 30 lp/mm resolution across the entire field of view is more than 0.3,and the maximum distortion is less than 0.9%.The designed standard HMD has a simple layout and compact structure,and the obtained results confirm the feasibility of the new system.

To eliminate the scatter light and central ghost in a classical fundus camera,the optical system of a catadioptric fundus camera with a field of view 40° and a working distance of 48 mm was designed.An off-axial reflecting ophthalmic lens with free form surfaces was designed to correct the off-axial aberrations.Two free-form-surfaces were introduced in the imaging objective system to correct the residual off-axial aberrations of the reflective ophthalmic lens.In the optimization of the imaging system,an eye model with varying defocuses was proposed to eliminate the negative effect of eye aberrations as well as to accommodate the eye with different refractive errors.Three adjacent illumination rings were introduced in the illumination part to avoid the undesirable light reflected by the eye optical system.Experiments show that the accommodation range of the system is between-10 m-1 and 10 m-1,the resolution at the object plane is 33 lp/mm across the entire field of view,and the maximum distortion is less than 8.5%.Furthermore,the illumination non-uniformity is less than 15% in the conditions without scatter light and central ghost.The designed catadioptric fundus camera with a free-form-surfaces show a satisfactory large field of view and a large working distance,and removes the undesirable scatter light and central ghost greatly.

The polishing principle of Double-Swing Method(DSM) was introduced,the relative movement characteristic between polishing lap and workpiece was analyzed,and the influence of polishing parameters on the relative movement was discussed.A mathematical model of the DSM in a movement state was established and its movement was simulated in a programming language.Then,simulation effects under different parameters was compared.The shape model of the polishing lap was presented,and the material removal character of the polishing lap with diffident shapes was verified.Finally,a rectangle off-axis aspheric mirror in a size of 224 mm×108 mm was polished by the DSM.The experiment result shows that to manufacture the off-axis aspheric mirror by the DSM can control the middle-frequency error and can obtain high working efficiency,and the surface precision is about λ/30(rms,@633nm).Therefore,the DSM benefits the development of the manufacture technique for off-axis aspheric mirrors.

Optical tests for the off-axis aspherics in optical processing and optical assembling were researched and the effect of adjustment errors on the wavefront aberration was analyzed.By taking an off-axis aspherics with the radiu of 10 000 mm,quadratic surface coefficient of-1,diameter of 500 mm and the lateral displacement of 425 mm for an example,the physical model and mathematical model to describe the relationship between the adjustment parameters and the wavefront aberration were estabished.The adjustment parameters included the pitch and high-low errors,beat and off-axis distance errors,and the rotating parameters around the secondary optical axis.The matlab software was used to simulate the influence of the wavefront aberration on the adjustment errors.Then,the experiments were performed to examine the simulation results.It shows that the the simulation results are well concident with the experiment ones,which proves the theory model in correct.The obtained results are also suitable for the test and alignment of other off-axis aspherics.

This paper studied how to improve the glass surface strength.The manufacture process in which the surface strength of glass changes was explored.According to the values of surface strength variation and the strength curves under different grinding processes,the reasons that the surface strength decreased and the related measures were given.Then,the etching method for releasing stress concentration and the max surface compressive stress strengthening theory were described,and the effects of different material removal modes on the surface strength of brittle materials were analyzed.A ductile grinding mode was introduced and its main manufacture requirements were given.The roughness ranges for different non-imaging surfaces were summarized,and corresponding solutions were advanced.The experiments show that as the material removal rate is set to be less than or equal to 25 μm/h and the abrasive size less than or equal to 15 μm,the polishing-similar surface will be achieved for several materials.The ductile grinding can induce an increase of the max surface compressive stress and avoid longitudinal micro-cracks which reduce the glass surface strength,so it is a reasonable grinding mode for glass surface strength improvement.