Patents by Inventor Zhen-tao Yan

Zhen-tao Yan has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Objective lens system
    Patent number: 7787189
    Abstract: An objective lens system includes a first lens group having a focal length F1 for focusing, a second lens group, which is a system of magnification variation having a focal length F2, a third lens group for compensation and having a focal length F3 and a fourth lens group having a focal length F4. The first lens group has a positive first lens assembly with a focal length F1a and a negative second lens assembly with a focal length F1b. The third lens group ensures an image point of the second lens group falls within the focal length F3 thereof. The first, second, third and fourth lens groups commonly form a finite conjugative system of magnification variation. Moreover, the objective lens system, as a whole, has a negative focal length.
    Type: Grant
    Filed: March 21, 2007
    Date of Patent: August 31, 2010
    Assignee: Asia Optical Co., Inc
    Inventor: Zhen-tao Yan
  • OBJECTIVE LENS SYSTEM
    Publication number: 20080055737
    Abstract: An objective lens system includes a first lens group having a focal length F1 for focusing, a second lens group, which is a system of magnification variation having a focal length F2, a third lens group for compensation and having a focal length F3 and a fourth lens group having a focal length F4. The first lens group has a positive first lens assembly with a focal length F1a and a negative second lens assembly with a focal length F1b. The third lens group ensures an image point of the second lens group falls within the focal length F3 thereof. The first, second, third and fourth lens groups commonly form a finite conjugative system of magnification variation. Moreover, the objective lens system, as a whole, has a negative focal length.
    Type: Application
    Filed: March 21, 2007
    Publication date: March 6, 2008
    Applicant: Asia Optical Co., Inc
    Inventor: Zhen-tao Yan