Before discussing the Guangdong grating ruler, let me first explain what a grating is. A grating is an optical device composed of a large number of parallel slits of equal width and spacing. Commonly used gratings are made by carving a large number of parallel scratches on a glass sheet. The scratches are opaque parts, and the smooth part between the two scratches can transmit light, equivalent to a slit. The refined grating is engraved with thousands or even tens of thousands of notches within a width of 1cm. This type of grating that uses transmitted light diffraction is called a transmission grating, and there are also gratings that use reflected light diffraction between two notches. For example, if many parallel notches are engraved on a surface coated with a metal layer, and the smooth metal surface between the two notches can reflect light, this type of grating is called a reflection grating.

And Guangdong grating ruler is just one type of grating. According to its meaning, Guangdong grating ruler is a measurement feedback device that works based on the optical principles of gratings. It is commonly used in closed-loop servo systems of CNC machine tools for detecting linear or angular displacement, and the measured output signal is a digital pulse. It has the characteristics of large detection range, high detection accuracy, and fast response speed. The above figure is an analytical diagram of a straight-line Guangdong grating ruler by Heidenhain.

I believe you have already seen that the Guangdong grating ruler consists of two parts: the ruler grating and the grating reading head. The key part of its detection device is the grating reading head, which is composed of a light source, a converging lens, an indicator grating, photoelectric components, and an adjustment mechanism.