Motor-driven focusing apparatus of a sighting telescope

• US 6,269,580 B1
• Filed: 10/14/1999
• Issued: 08/07/2001
• Est. Priority Date: 10/14/1998
• Status: Expired due to Fees

• Current Assignee: Asahi Kogaku Kogyo Kabushiki Kaisha
• Original Assignee: Asahi Kogaku Kogyo Kabushiki Kaisha
• Inventors: Suzuki, Shinichi
• Primary Examiner(s): Jordan, Charles T.
• Assistant Examiner(s): Buckley, Denise J
• Application Number:
  US09/417,623
• Time in Patent Office: 663 Days
• Field of Search: 359/429, 359/426, 359/422, 421/19, 332/45, 332/46
• US Class Current: 42/119
• CPC Class Codes: G01C 1/02 Theodolites
• CPC Class Codes: G02B 23/14 Viewfinders for photographic apparatus G03B13/02
• CPC Class Codes: G02B 7/08 adapted to co-operate with a remote control mechanism

Abstract

A motor-driven focusing apparatus of a telescope, includes a telescopic optical system which includes a focusing lens group guided along an optical axis; a motor-driven lens moving device which drives the focusing lens group along the optical axis; a manual operating switch for actuating the motor-driven lens moving device; and a lens-control device for controlling the motor-driven lens moving device when the manual operating switch is turned ON, so that the moving amount per unit time of a focal point of the telescopic optical system, that is caused by a movement of the focusing lens group, is kept substantially at a constant speed regardless of the position of the focusing lens group on the optical axis, the constant speed being selected from one or more constant speeds.

Claims

1. A motor-driven focusing apparatus of a telescope, comprising:

a telescopic optical system which comprises a focusing lens group guided along an optical axis;

a motor-driven lens moving device which drives said focusing lens group along the optical axis;

a manual operating switch for actuating said motor-driven lens moving device; and

a lens-control device for controlling said motor-driven lens moving device when said manual operating switch is turned ON, so that the moving amount per unit time of a focal point of said telescopic optical system, that is caused by a movement of said focusing lens group, is kept substantially at a constant speed regardless of the position of said focusing lens group on the optical axis, said constant speed being selected from one or more constant speeds.

2. The motor-driven focusing apparatus according to claim 1, wherein said manual operating switch comprises a speed changing function that can change the moving amount per unit time of a focal point of said telescope via said motor-driven lens moving device by said constant speed selected from one or more constant speeds.

3. The motor-driven focusing apparatus according to claim 1, further comprising:

a lens-position detector for detecting the position of said focusing lens group on said optical axis; and

a memory in which compensation data for compensating a moving amount per unit time of said focusing lens group for each position of the focusing lens group on said optical axis within a movable range of the focusing lens group is stored;

wherein said lens-control device inputs data from said compensation data stored in said memory for compensating said amount of driving of said focusing lens group for a position of the focusing lens group that is detected by said lens-position detector, so as to control said motor-driven lens moving device in accordance with said input data.

4. The motor-driven focusing apparatus according to claim 1, further comprising:

a lens-position detector for detecting said position of said focusing lens group on said optical axis; and

a memory which stores a formula for calculating compensation data for compensating an amount of driving of said focusing lens group for each position of the focusing lens group on the optical axis within a movable range of the focusing lens group;

wherein said lens-control device calculates said compensation data with said formula in accordance with said position of said focusing lens group that is detected by said lens-position detector to control said motor-driven lens moving device in accordance with said compensation data.

5. The motor-driven focusing apparatus according to claim 1, wherein said motor-driven focusing apparatus is incorporated in a surveying instrument.

6. The motor-driven focusing apparatus according to claim 1, wherein said manual operating switch comprises a rotatable control lever.

7. The motor-driven focusing apparatus according to claim 1, wherein said telescope comprises an autofocusing system having an AF start switch that is actuated to bring a sighting object into focus upon said AF start switch being turned ON.

8. A sighting telescope incorporated in a surveying instrument, comprising:

a telescopic optical system which comprises a focusing lens group guided along an optical axis;

an autofocusing system which starts moving said focusing lens group along said optical axis to bring a sighting object into focus upon an AF start switch being turned ON;

a motor-driven auxiliary focusing apparatus that moves said focusing lens group along said optical axis to finely adjust the position of said focusing lens group on said optical axis, said motor-driven auxiliary focusing apparatus comprising an manual operating switch that is operated to actuate said motor-driven auxiliary focusing apparatus; and

a lens-control device for controlling said motor-driven auxiliary focusing apparatus, when said manual operating switch is turned ON, so that the moving amount per unit time of a focal point of said telescopic optical system, that is caused by a movement of said focusing lens group, is kept substantially at a constant speed regardless of the position of said focusing lens group on the optical axis, said constant speed being selected from one or more constant speeds.

9. The sighting telescope incorporated in a surveying instrument according to claim 8, wherein said manual operating switch comprises a speed changing function that can change the moving amount per unit time of a focal point of said telescope via said motor-driven lens moving device by said constant speed selected from one or more constant speeds.

10. The sighting telescope incorporated in a surveying instrument according to claim 8, further comprising:

a lens-position detector for detecting the position of said focusing lens group on said optical axis; and

a memory in which compensation data for compensating an amount of driving of said focusing lens group for each position of the focusing lens group on said optical axis within a movable range of the focusing lens group is stored;

wherein said lens-control device inputs data from said compensation data stored in said memory for compensating said amount of driving of said focusing lens group for a position of the focusing lens group that is detected by said lens-position detector, so as to control said motor-driven lens moving device in accordance with said input data.

11. The sighting telescope incorporated in a surveying instrument according to claim 8, further comprising:

a lens-position detector for detecting the position of said focusing lens group on said optical axis; and

a memory which stores a formula for calculating compensation data for compensating an amount of driving of said focusing lens group for each position of the focusing lens group on the optical axis within a movable range of the focusing lens group;

wherein said lens-control device calculates said compensation data with said formula in accordance with said position of said focusing lens group that is detected by said lens-position detector to control said motor-driven lens moving device in accordance with said compensation data.

12. The sighting telescope incorporated in a surveying instrument according to claim 8, wherein said manual operating switch comprises a rotatable control lever.