Encoder, lens apparatus, and camera capable of detecting position of object

1. An encoder comprising:

a base;

a cylinder rotatable in a circumferential direction with respect to the base;

at least three supporting portions provided on the base and rotatably supporting the cylinder;

a connecting portion provided on the cylinder and connected to a drive mechanism of a lens unit;

a scale; and

a detector configured to detect a position of the cylinder with respect to the base by using the scale,

wherein the connecting portion is rotatable within a first range between two supporting portions, of the at least three supporting portions, next to each other, and

wherein the detector is arranged within a second range different from the first range.

2. The encoder according to claim 1 , wherein a position of the connecting portion and a position of the detector are symmetric to each other with respect to a center of the cylinder.

3. The encoder according to claim 1 , wherein at least one of the supporting portions includes a rotating portion that rotates with respect to the base and a biasing portion that biases the rotating portion in a direction of the base.

4. The encoder according to claim 1 ,

wherein the cylinder is an injection-molded product having an inner wall of the cylinder that is formed by using a slide mold for an inside diameter, and

wherein each of regions of the inner wall of the cylinder where the at least three supporting portions limit a position of the cylinder is formed by one slide core of the slide mold for the inside diameter.

5. The encoder according to claim 4 , wherein a surface of the inner wall of the cylinder within a detection range of the scale is formed by one slide core of the slide mold for the inside diameter.

6. The encoder according to claim 1 ,

wherein the cylinder includes:

a fixed holder holding the scale;

a scale holder configured to be movable in the circumferential direction of the cylinder and holding the scale; and

a scale biasing portion configured to bias the scale via the scale holder toward a side of the fixed holder so that the scale is attached to an inner wall of the cylinder.

7. A lens apparatus comprising:

a lens movable in an optical axis direction;

a cylinder rotatable in a circumferential direction with respect to a base so as to move the lens in an optical axis direction;

at least three supporting portions provided on a base and rotatably supporting the cylinder;

a connecting portion provided on the cylinder and connected to a drive mechanism of a lens unit;

a scale; and

a detector configured to detect a position of the cylinder with respect to the base by using the scale,

wherein the connecting portion is rotatable within a first range between two supporting portions, of the at least three supporting portions, next to each other, and

wherein the detector is arranged within a second range different from the first range.

8. A camera comprising:

a lens movable in an optical axis direction;

an image pickup element configured to perform a photoelectric conversion of an object image from the lens;

a cylinder rotatable in a circumferential direction with respect to a base so as to move the lens in the optical axis direction;

at least three supporting portions provided on the base and rotatably supporting the cylinder;

a connecting portion provided on the cylinder and connected to a drive mechanism of a lens unit;

a scale; and

a detector configured to detect a position of the cylinder with respect to the base by using the scale,

wherein the connecting portion is rotatable within a first range between two supporting portions, of the at least three supporting portions, next to each other, and

wherein the detector is arranged within a second range different from the first range.