Home of RF and Wireless Vendors and Resources

One Stop For Your RF and Wireless Need

Transmissive optical sensor vs retro-reflective optical sensor | Difference between transmissive optical sensor and retro-reflective optical sensor

This page compares transmissive optical sensor vs retro-reflective optical sensor and mentions difference between transmissive optical sensor and retro-reflective optical sensor.

What is optical sensor?

• The method of sensing light rays is known as optical sensing The sensor type used for optical sensing is known as optical sensor.
• Optical Sensor converts light rays into electrical signal. This is similar to the function performed by photoresistor.
• In general, there are two components in optical sensing viz. transmitter (i.e. optical source such as LED) and receiver (optical detector such as photodiode or photo-transistor).

optical sensing using optical sensor

• Optical sensors are categorized into transmissive and reflective (or retro-reflective) types.
• Refer optical sensor basics and types >>.

Transmissive optical sensor

transmissive optical sensor

• The figure depicts transmissive optical sensor.
• It uses pair of components viz. one emitting light and the other receiving it. Both light emitter and light detector face each other across a small gap and are contained in a single module.
• The sensor is triggered if an object interrupts or reflects the light beam.
• It is also known as through-beam sensor.

Following are the popular transmissive optical sensors.
• Vishay TCZT8020, houses infrared LED as light source and phototransistor as detector.
• Omron EE-SX

Retro-reflective optical sensor

Retro-reflective optical sensor

• The figure depicts retro-reflective optical sensor.
• It consists of a light emitter and a light detector, but they are placed adjacent to each other, facing in the same general direction.
• When both the transmit part and receive part are mounted in one single module, it is known as retro-reflective sensor. It is triggered in one of the following two ways.
➨1. An object passing in front of the light beam reflects it back to the detector. The object must be naturally reflective or must have a reflective patch applied to it.
➨2. A stationary reflector can be mounted opposite the light emitter in which case a detector beside the light emitter is triggered when the object interrupts the reflected light beam.

Following are the popular retro-reflective optical sensors.
• Rodan RT-530
• Optek OPB606A
• Vishay TCRT5000

Different types of Sensors Related links

Article on Sensors and Transducers>>
Proximity Sensor
Occupancy Sensor vs Motion Sensor
LVDT and RVDT sensor
Position, displacement and level sensor
force sensor and strain sensor
temperature sensor
pressure sensor
Humidity sensor
MEMS sensor
Touch sensor
Haptic sensor
Wireless sensor

Advantages and Disadvantages of other Sensor Types

Capacitive    Inductive    Photoelectric    Ultrasonic    Infrared    Motion    Biometric    Force    Humidity    Temperature    Light    Barometer    Sound    pH    Soil Moisture   

What is Difference between

difference between OFDM and OFDMA
Difference between SC-FDMA and OFDM
Difference between SISO and MIMO
Difference between TDD and FDD

RF and Wireless Terminologies

Share this page

Translate this page