Optical encoder with detector lens

Abstract

An optical encoder of a transmissive optical encoding system is disclosed. The optical encoder includes an emitter, a detector, and a detector lens. The emitter includes a light source and a collimating lens. The detector includes a plurality of photosensors to detect light from the emitter. The detector lens is aligned with the plurality of photosensors to direct the light toward the plurality of photosensors. Embodiments of the optical encoder provide an increased effective sensing area, increased power delivery to the detector, and increased encoder life.

Description

technical field [0001] The invention relates to an optical encoder with a detector lens. Background technique [0002] Optical encoders are used, for example, to monitor the movement of a shaft such as a crankshaft. Optical encoders monitor shaft motion in terms of shaft position and / or revolutions. Optical encoders typically utilize a code disc mounted to a shaft to modulate light as the shaft and code disc rotate. In a transmissive code wheel, the light is modulated as it traverses a track of transmissive areas on the code wheel. The transmissive regions are separated by non-transmissive regions. In a reflective code wheel, the light is modulated as it reflects off the track of the reflective areas on the code wheel. Reflective areas are separated by non-reflective areas. As the light is modulated in response to rotation of the code disc, a current signal is generated from the array of photosensors receiving the modulated light. This current signal is used, for examp...

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Problems solved by technology

This leads to encoder performance degradation

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