Photo Eyes – Photoelectric Sensors

Photo Eyes – Photoelectric Sensors

In the field of industrial automation, a sensor is a device that detects presence, such as a limit switch, pixel (photoelectric), or laser sensor.

Industrial sensors are available in all sizes, shapes and technologies. They are the eyes and ears on factory floors. The application requirements will determine which technology is best. Each technology has its own strengths and weaknesses. Inductive, capacitive and photoelectric technologies are the most common.

Photo Eyes – Photoelectric sensors emit a light beam that can be used to detect items, equipment, or surface changes. The operation consists of a light emitter and source, as well as a receiver which detects the changes in intensity of light reflected by a target object. A receiver measures the changes in light patterns when the light is interrupted by an object or reflected. The object or surface can then be recognized. They are therefore very common in many industrial manufacturing fields such as packaging, food, beverage, medical and others.

The emitter and the receiver of a through-beam sensor are housed in separate housings. The longest distances are possible with through-beam photo eyes, since the light is emitted directly from the emitter to the receiver.

Three main types of photo eyes are available:

Through beam sensing is also known as the opposed mode. It uses two devices to break up a beam. The light emitter is housed in one sensor, while the receiver is located in the other. Through-beam sensors detect objects by interrupting the light beam between two sensors. They can be used for:

• Detect very small objects
• Detect the fill levels inside containers
• Detect spliced or overlapped materials
• Detect the precise location of a specific object
• Detect the contents of a container
• Detect opaque objects

Retroreflective Sensing combines both the light source (source of illumination) and the receiving source (receiving source), which are located in the same housing. The sensor and reflector work together. The sensor emits light that is directed at the reflector. This light is then reflected back to the receiving element. In these situations, they are most useful to:

• Detect large objects
• Detect objects moving at high speeds
• Detect reflective tape at high speeds
• Sense a transparent (clear) glass or plastic product

Diffused sensing, or optical proximity sensing, the light source and receiver are also housed in the same device.  Diffused sensors detect an object when the light beam emitted toward the target is reflected by the target. Diffused sensors are a good option for automation because they are compact. All components are contained in one housing.

Use diffuse sensors to:

• Detect multiple objects on a common conveyor system
• Detect translucent objects
• Detect the fill level inside containers
• Detect the presence of parts, boxes, and web materials
• Detect specific identifying features to determine an object’s orientation
• Detect unwanted conditions for product inspection tasks

There are also Photo Eyes – photoelectric sensors with different characteristics.

Background suppressors work extremely well when both the target and the background are similar in reflectivity. For example, the light reflected from the background is about the same as the light reflected from the target.

Color contrast sensors are color sensors with RGB recognition that can be used in industrial applications. They also detect registration marks on a variety of backgrounds, including pastels that may be difficult to read.

Optical Fork Photoelectric Sensors offer a cost-effective and simple-to-use method for detecting small parts. These sensors eliminate alignment and adjustment problems associated with other solutions that use transmitted beams.

SUPERIOR® Optics is proud to have developed a precision lens specifically designed for the type photo eyes equipment that you manufacture. Our skills and expertise can be put to work for your benefit.