[54] AUTOMATIC FOCUSING DEVICE FOR VIDEO CAMERA OR THE LIKE
[75] Inventor: Koki Isago, Kanagawa, Japan
[73] Assignee: Ricoh Company, Ltd., Tokyo, Japan
[21] Appl. No.: 863,169
[22] Filed: May 14,1986
[30] Foreign Application Priority Data
May 16, 1985 [JP] Japan 60-104,695
[51] Int. CI.4 H04N 5/38
[52] U.S. CI 358/227; 354/402
[58] Field of Search 358/227; 354/402, 404
[56] References Cited
U.S. PATENT DOCUMENTS
4,422,097 12/1983 Inuiya 358/227
4,615,598 10/1986 Koshiishi 358/227
Primary Examiner—James L. Dwyer
Assistant Examiner—L. C. Schroeder
Attorney, Agent, or Firm—Obion, Fisher, Spivak,
McClelland, & Maier
[57] ABSTRACT
An automatic focusing device for use with a solid-state self-scanned image sensor having a rectangular light detecting area for scanning an object image and converting the same to a video signal, including a focus detecting means, a driver means and a control means. The focus detecting means produces a focus signal from the video signal. The driver means moves a focusing lens group in an image-forming lens system in one direction or the other along its optical axis in increments or steps each equal to a predetermined small distance Ax. The control means is responsive to the focus signal for controlling the driver means to bring the lens group into a position in which a maximum focus signal is produced. Even after the lens group has been brought into the properly focused position, the control means controls the focus detecting means to generate a focus signal and resumes the focusing process when the generated focus signal varies beyond a certain value.
1 Claim, 4 Drawing Figures
