JP2004028905A5 - - Google Patents

Claims (7)

A light source, a scale that moves relative to the light source, and on which a periodic optical pattern having a predetermined pitch is formed, and reflected light or transmitted light from the optical pattern of the scale by a light beam emitted from the light source In an optical encoder comprising a photodetector for receiving light,
The scale has at least one reflective optical pattern and at least one transmissive optical pattern;
A first photodetector for receiving reflected light from the reflective optical pattern of the scale; and a second photodetector for receiving transmitted light from the transmissive optical pattern of the scale. And an optical encoder. 2. The optical encoder according to claim 1, wherein the track on which the reflective optical pattern of the scale is formed and the track on which the transmission optical pattern of the scale is formed have an overlap. The pitch and Pr with the reflective optical pattern of the scale, when a pitch having a transmissive optical pattern of the scale was Pt, claim 2, characterized in that it has a Pt> Pr the relationship The optical encoder described in 1. The reflective optical pattern of the scale and the transmissive optical pattern of the scale are formed on the same track so that the pitch of the reflective optical pattern of the scale is Pr, and the transmission of the scale 2. The optical encoder according to claim 1 , wherein when the pitch of the optical pattern of the mold is Pt, the relationship is Pt> 10 × Pr . And Wr track width of the reflection type optical pattern of the scale, when the track width of the transmission type of optical pattern of the scale was Wt, claim, characterized in that it has a Wt ≧ Wr becomes relations 4 The optical encoder described in 1. A light source, a scale that moves relative to the light source, and on which a periodic optical pattern having a predetermined pitch is formed, and light reflected from the optical pattern of the scale by a light beam emitted from the light source are received. In an optical encoder comprising a photodetector,
The scale has at least one reflective optical pattern and at least one magnetic pattern whose magnetic properties change periodically;
The photodetector receives reflected light from the reflective optical pattern of the scale;
An optical encoder further comprising a magnetic detector for detecting a periodic change in the magnetic pattern of the scale. The reflective optical pattern of the scale and the magnetic pattern of the scale are formed on the same track, the pitch of the reflective optical pattern of the scale is Pr, and the magnetic pattern of the scale has 7. The optical encoder according to claim 6, wherein when the pitch is Pm, the relationship is Pm> 10 × Pr .