Variable magnification projection optical system and projection device

• Main Author: MASUI ATSUO
• Format: Patent
• Language: Chinese; English
• Published: 13.12.2022
• Subjects: ACCESSORIES THEREFOR; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USINGWAVES OTHER THAN OPTICAL WAVES; APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FORPROJECTING OR VIEWING THEM; CINEMATOGRAPHY; ELECTROGRAPHY; HOLOGRAPHY; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PHOTOGRAPHY; PHYSICS

The invention relates to a variable magnification projection optical system and a projection apparatus. The variable magnification projection optical system includes, in order from the magnification side, a first lens group having a negative refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power. During zooming, the first lens group is fixed, and the second lens group and the third lens group move. The second lens group includes a plurality of lenses having a positive refractive power. All lenses having a positive refractive power in the first lens group and the second lens group are formed of a nitre material having a transmittance greater than 0.98 at a thickness of 10 mm for light having a wavelength of 440 nm. 本公开涉及变倍投影光学系统以及投影装置。变倍投影光学系统从放大侧起依次具备具有负的光焦度的第1透镜群、具有负的光焦度的第2透镜群以及具有正的光焦度的第3透镜群。在变倍时，第1透镜群被固定并且第2透镜群以及第3透镜群移动。第2透镜群包括具有正的光焦度的多个透镜。第1透镜群以及第2透镜群内的具有正的光焦度的所有透镜由针对具有440nm的波长的光在10mm的厚度下具有大于0.98的透射率的硝材形成。