There’s so much innovation in today’s machinery. From handheld medical imaging equipment to automated mechanical robots that move boxes and supplies around a warehouse, today’s tools are complex and dynamic. So how do these sophisticated autonomous machines stay on track? Thank the intricate designs and functionality of optical encoder components. These pivotal parts work together to provide vital position and motion data feedback. Let’s dive into the details of these essential components and how they work together. 

The Building Blocks of an Optical Encoder

As we mentioned before, optical encoders are motion feedback devices. These devices measure changes in position and speed to help ensure a robotic arm, assembly line, or medical imaging tool stays on its intended path of motion. 

There are many types of encoders, but the optical encoder is amongst the most commonly used encoder types because of its incredible accuracy. The main optical encoder components that make up the device are a light source and sensor, a disc or scale, a circuit, and the housing assembly. 

Light Source and Sensor

The light source on an optical encoder is typically an LED that emits a constant stream of light. The sensors, sometimes called a photodetector assembly, are light-detecting sensors that react to light by emitting a specific type of signal wave, called a sinusoidal waveform.  

Disc or Scale

Arguably to the most crucial component, the disc or scale is a substrate that’s etched with small cutouts or reflective material along a line called the code strip. As the machine moves, the disc or scale moves in sync, and the light passes through or reflects off the etchings. 


The optical encoder circuit receives the sinusoidal waveform from the sensor and transforms it into a compatible signal for the main computer to interpret. Most circuits transform signals into a pulse signal, which codes to a simple on/off. 

Housing Assembly

The housing assembly holds all the different components in place. These housing assemblies can be made out of various durable materials and can be mounted to different machines. 

How Optical Encoder Components Work Together

Optical encoders measure changes in position by passing light through the rotating disc or linear scale.

The light source emits a constant stream of light directly at the code strip on the disc or scale. The sensor placed on the other side of the disc or scale measures every time the light passes through the slots in the disc. For reflective optical encoders, the sensor and LED are placed on the same side of the disc. 

When the sensor first picks up the light beam, it sends the sinusoidal wave signal to the circuit. Next, the circuit interprets the signal and passes the information on to the main computer. Finally, the computer interprets the data and performs specific actions like stop, start, turn, etc. 

Without this feedback information, there would be no way of knowing if the machine’s intended actions were completed successfully. 

Effective Encoders Require High-Quality, Custom Components 

As you now know, encoder components are crucial to the accuracy and effectiveness of the encoder and, by extension, the machine as a whole. So, you want to ensure your machines stay on track and in line? Then you need to invest in high-quality optical encoder components. 

At Photo Solutions, we specialize in custom encoder discs and scales for applications across industries, including medical, aerospace, automation, and more. With over 30 years of experience, we are the go-to producer for encoder discs and scales. 

Learn more about our custom discs and scales today.