Optical encoder, bending operation system, and method of detecting displacement of linear power transmission member

An optical encoder comprising:

• a linear power transmission member which moves longitudinally;
• a reflector which is fixed onto an outer peripheral surface of the linear power transmission member and which is longitudinally movable integrally with the linear power transmission member, the reflector including a slit portion in which two kinds of reflecting portions different in reflectance are longitudinally arranged with a predetermined pattern;
• a light source which radiates light;
• a linear light transmitter which guides the light from the light source to the slit portion and to which reflection light reflected from the slit portion is guided;
• and
• a holding member which longitudinally movably holds the linear power transmission member and the reflector and also holds the linear light transmitter at such a position that allows the light to enter the slit portion and allows the reflection light from the slit portion to be guided;
• a light receiving element which receives the reflection light in the slit portion guided from the linear light transmitter and which detects an electric signal indicating a displacement of the reflector and a light amount;
• a signal processing mechanism configured to convert the electric signal into a pulse signal having a predetermined threshold;
• and
• a calculation mechanism configured to calculate the longitudinal displacement of the reflector from a number of pulses of the pulse signal.

A bending operation system comprising:

• an elongated tubular part;
• a linear power transmission member disposed in the tubular part;
• a moving part to which a distal end of the linear power transmission member is connected and which is configured to perform a bending operation in accordance with a longitudinal movement of the linear power transmission member;
• a driving mechanism configured to drive the moving part;
• and
• an optical encoder including:
• a reflector which is provided on an outer peripheral surface of the linear power transmission member and which is longitudinally movable integrally with the linear power transmission member, the reflector including two kinds of reflecting portions different in reflectance are longitudinally arranged;
• a light source which radiates light;
• a linear light transmitter which guides the light from the light source to the reflector and to which reflection light reflected from the reflector is guided;
• and
• a calculation mechanism configured to calculate a longitudinal displacement of the reflector on the basis of an intensity of the reflection light from the reflector which is guided via the linear light transmitter.

A bending operation system comprising:

• an elongated tubular part;
• a linear power transmission member disposed in the tubular part;
• a moving part to which a distal end of the linear power transmission member is connected and which is configured to perform a bending operation in accordance with a longitudinal movement of the linear power transmission member;
• a driving mechanism configured to drive the moving part;
• and
• an optical encoder including:
• a reflector which is fixed onto the outer peripheral surface of the linear power transmission member and which is longitudinally movable integrally with the linear power transmission member, the reflector including a slit portion in which two kinds of reflecting portions different in reflectance are longitudinally arranged with a predetermined pattern;
• a light source which radiates light;
• a linear light transmitter which guides the light from the light source to the slit portion and to which reflection light reflected from the slit portion is guided;
• a holding member which longitudinally movably holds the linear power transmission member and the reflector and also holds the linear light transmitter at such a position that allows the light to enter the slit portion and allows the reflection light from the slit portion to be guided;
• a light receiving element which receives the reflection light in the slit portion guided from the linear light transmitter and which detects an electric signal indicating a displacement of the reflector and a light amount;
• a signal processing mechanism configured to convert the electric signal into a pulse signal having a predetermined threshold;
• and
• a calculation mechanism configured to calculate the longitudinal displacement of the reflector from a number of pulses of the pulse signal and also calculate a bending angle and a bending direction of the moving part from the longitudinal displacement of the reflector.

A method of detecting a displacement of a linear power transmission member, the method comprising:

• causing light to enter two kinds of reflecting parts from a light source via a linear light transmitter, the two kinds of reflecting parts being provided in a reflector which is longitudinally movable integrally with the linear power transmission member;
• receiving, via the linear light transmitter, reflection light reflected from the reflector;
• and
• detecting a longitudinal displacement of the reflector on the basis of an intensity of the received light.

A method of detecting a displacement of a linear power transmission member, the method comprising:

• causing light to enter a slit portion from a light source via a linear light transmitter, the slit portion being provided in a reflector which is longitudinally movable integrally with the linear power transmission member, the slit portion including two kinds of reflecting parts different in reflectance which are longitudinally arranged with a predetermined pattern;
• guiding reflection light reflected by the slit portion to the linear light transmitter and receiving the light by a light receiving element;
• detecting, by the light receiving element, an electric signal indicating a displacement of the reflector and a light amount;
• converting, by signal processing mechanism, the electric signal into a pulse signal having a predetermined threshold;
• and
• calculating, by calculation mechanism, the longitudinal displacement of the reflector from a number of pulses of the pulse signal.