Abstract: A coding element such as a codewheel includes first and second surfaces that are configured with respect to each other and with respect to a light beam such that the light beam is reflected at the two surfaces using the optical phenomenon of total internal reflection. The coding element also includes a coding pattern that is aligned in an optical path of the light beam after the light beam has reflected off of both of the surfaces. A coding element with surfaces that reflect a light beam as a result of total internal reflection can be utilized in an encoding system that operates in transmission while the light source and the photodetector array are located on the same side of the coding element.

Abstract: An optical encoder includes a coding element having a track with multiple transparent sections, a light source positioned to output light to the track, and a photodetector array, positioned to detect light that passes through the transparent sections of the track. The photodetectors of the photodetector array have larger width dimensions than the width dimensions of the transparent sections of the track. Resolution of the optical encoder may be adjusted by changing the resolution of the coding element.

Abstract: In one embodiment, an optical encoder device is provided with an optical encoder to detect codewheel/codestrip positions; a housing to accommodate the optical encoder; a first tapered guidepost protruding from a sidewall of the optical encoder housing; and a second tapered guidepost protruding from the sidewall of the optical encoder housing and extending substantially parallel to the first tapered guidepost. Other embodiments are also disclosed.

Abstract: A polaroid encoder system for detecting movement is disclosed. The system includes a movable polarizing code element. A detector module detects an amplitude based on how much illumination passes through one portion of the movable polarizing code element. A quadrant of the movable polarizing code element is determined based on how much illumination passes through another portion of the movable polarizing code element. The angular position of the movable polarizing code element can then be determined by using amplitude and the quadrant information.

Abstract: A code disk, an optical encoder using such a disk and a method thereof are described. The code disk includes a first region on the disk and a second region that is adjacent to the first region. The first region increases continuously in size in a radial direction from a minimum at a first angular position to a maximum that occurs 360 degrees from the first angular position. One of the first and second regions allows light to be transmitted therethrough to a detector, and the other of the first and second regions prevents light from being transmitted therethrough. The detector generates an output that corresponds to the amount of light transmitted through the code disk.