Optical encoder

An optical encoder comprising:

• a scale which is installed on one member of which, a displacement is detected;
• and
• a detecting head which is installed on the other member which moves relatively with respect to the first member, and which is disposed facing the scale, wherein
• the scale is provided with a predetermined optical pattern in the direction of relative movement, and
• the detecting head is provided with a light emitting section which irradiates predetermined light to the scale, a light detecting section which includes a light receiving surface which receives light reflected by the optical pattern upon being irradiated to the scale from the light emitting section, and which detects the light distribution formed on the light receiving surface, and a light transmitting member which is disposed on a surface of the light emitting section and the light detecting section, toward the scale, and
• a light propagation controlling pattern for controlling propagation of light is disposed on at least a part of a surface of the light transmitting member, facing the scale,
• wherein the light propagation controlling pattern is disposed on a portion of a surface of the light transmitting member, which does not contribute directly to any encoder signal.

An optical encoder comprising:

• a scale which is installed on one member of which, a displacement is detected;
• and
• a detecting head which is installed on the other member which moves relatively with respect to the first member, and which is disposed facing the scale, wherein
• the scale is provided with a predetermined optical pattern in the direction of relative movement, and
• the detecting head is provided with a light emitting section which irradiates predetermined light to the scale, a light detecting section which includes a light receiving surface which receives light reflected by the optical pattern upon being irradiated to the scale from the light emitting section, and which detects the light distribution formed on the light receiving surface, and a light transmitting member which is disposed on a surface of the light emitting section and the light detecting section, toward the scale, and
• a light propagation controlling pattern for controlling propagation of light is disposed on at least a part of a surface of the light transmitting member, facing the scale,
• wherein the light propagation controlling pattern is a pattern for controlling at least light propagation induced by reflection,
• for a path of light from the light emitting section up to the light detecting section via the light propagation controlling pattern of the surface of the light transmitting member, if it were not for the light propagation controlling pattern, the angle at which at least a part of the light passing through the path of light is incident on the surface of the light transmitting member, would be larger than the critical angle of total reflection at the interface between the light transmitting member and the exterior.

An optical encoder comprising:

• a scale which is installed on one member of which, a displacement is detected;
• and
• a detecting head which is installed on the other member which moves relatively with respect to the first member, and which is disposed facing the scale, wherein
• the scale is provided with a predetermined optical pattern in the direction of relative movement, and
• the detecting head is provided with a light emitting section which irradiates predetermined light to the scale, a light detecting section which includes a light receiving surface which receives light reflected by the optical pattern upon being irradiated to the scale from the light emitting section, and which detects the light distribution formed on the light receiving surface, and a light transmitting member which is disposed on a surface of the light emitting section and the light detecting section, toward the scale, and
• a light propagation controlling pattern for controlling light propagation induced by transmission using any one of a high-reflection pattern, a light absorption pattern and the direction of reflection bending pattern, is disposed on at least a part of a surface of the light transmitting member, facing the scale.