What is the working principle of the grating ruler

The working principle of the encoder is based on optics and electronics. Scales usually consist of a transparent base and a readhead. The base has a series of parallel grating lines that have been etched into the transparent base at very precise intervals. A photoelectric sensor is built into the readhead that detects reflected light on the grating lines to determine the position and direction of movement of the readhead. The readhead also includes a digital display that shows the position of the readhead relative to the base.

As the readhead moves along the base, the grating lines create a spot of light on the receiver of the photoelectric sensor. These spots of light cause the photodiode in the photosensor to generate a charge proportional to the light intensity. Photoelectric sensors measure the magnitude of these charges and convert them into digital signals to determine the position and direction of movement of the readhead. By comparing the position information at different times, the moving distance and speed of the reading head can be calculated, so as to realize the measurement of length or position.

Due to the very high precision and stability of the grating lines of the grating scale, very high measurement accuracy can be achieved, down to the sub-micron level. In addition, the digital signal output of the grating scale facilitates the connection with computers, controllers and other equipment, and realizes a high degree of automation and precision control.