Optical sensor is a device that converts optical signals into electrical signals, which plays a crucial role in automated production. With its excellent performance and wide applicability, the optical sensor has become an expert in the field, and its products are widely used in logistics automation, packaging industry, automotive industry, electronics industry, lithium battery industry and other fields. Today, let’s explore the principle of optical sensors.

SERVOSTAR 310 Composition of photoelectric switch

Photoelectric switch is the most basic form of optical sensor, which is mainly composed of light source, photodetector, switching circuit and so on. When there is an object blocking the light, the light signal received by the photodetector is weakened, which triggers the switching circuit and outputs the electrical signal. Using advanced photoelectric detection technology, the optical sensor can achieve high-precision optical signal detection, thus ensuring the accuracy of the switch.

Spectrum and light source type:

Spectrum refers to the distribution of light in terms of wavelength or frequency. The optical sensor is located in the spectrum of visible light wavelength (390~780nm) and infrared light wavelength (780nm~1mm), suitable for different application scenarios. The main types of light sources are LED light sources, infrared light sources, laser light sources and so on.

LED light source: spot visible and divergent, easy to install and adjust, is an economical photoelectric common light source.

SERVOSTAR 310 Infrared light source: mainly divergent light source, strong anti-interference ability, but the light source is invisible and inconvenient to adjust.

Laser light source: long transmission distance, small spot, high light intensity, strong anti-interference ability, suitable for detecting small objects.

Classification and working principle of optical sensors

The working principle of optical sensors is mainly to convert optical signals into electrical signals through the photoelectric effect. Lloyd’s optical sensor adopts three principles of mirror reflection, diffuse reflection and reflection to achieve measurement.

Mirror reflection type optical sensor

The transmitter and receiver of the mirror reflection sensor are in the same device, and a reflector plate needs to be installed on the opposite side to return the light signal through the reflector plate. When an object blocks the reflector, the sensor will output a response signal.

advantage
• Reduced installation (1 connection, installation, alignment)
• Reduced space (with flat mirrors)
 suitable for detecting reflective or transparent objects
• has higher economic benefits compared to beam sensors

Inferior position
• has a shorter working distance than the contrast-fire detection method
• When the reflector is far away, the spot is difficult to find and difficult to install

Beam type optical sensor

The anti-beam detection mode requires the transmitter and receiver to SERVOSTAR 310 be installed opposite to ensure that the receiver can receive the light emitted by the transmitter. When the measured object blocks the light beam, the sensor will sense and make the corresponding signal output.

advantage
 has a very large working distance
 Use gaps, holes, or laser light sources to detect smaller objects
• stably detects objects with bright surfaces

Inferior position
 Relatively high cost (more materials and installation time required due to separate transmitter and receiver)
 Double workload requires more installation, alignment and wiring
• is not suitable for detecting transparent objects