sunshine

sky light

thermal radiation light source

gas discharge light source

electroluminescent light source

Laser light source

The external photoelectric effect when electrons overflow from the surface of a substance, and the electrons which do not overflow from the surface participate in the internal conduction of the substance: the internal photoelectric effect

principle

type

Photoconductivity effect

photovoltaic effect

subtopic

charge generation

charge storage

charge transfer

Charge detection

camera, image sensor

visual system

Linear array CCD for workpiece size measurement

When a semiconductor optoelectronic device is unevenly spaced by light, electron holes are generated in the illuminated part, and the carrier concentration is greater than in the unilluminated part. A carrier concentration gradient appears, causing carrier diffusion. If electrons diffuse faster than holes, the illuminated part will be positively charged and the unilluminated part will be negatively charged, thus generating an electromotive force.

Two assumptions: ① The resistance of the PSD surface layer is uniform ② The load resistor resistance is ignored Conclusion: ① The current is inversely proportional to the distance from the light spot to the corresponding electrode; ② The sum of I1 and 12 is equal to the total photogenerated current

Px is called the one-dimensional PSD position output signal. It has a linear relationship with the position coordinate x of the light point on the photosensitive surface and has nothing to do with the incident light intensity. This is the position detection characteristic of PSD. It has nothing to do with the spot intensity distribution, symmetry and size on the surface, only the position!

3D motion measurement

Micro angle measurement

Displacement measurement

Parallelism measurement

subtopic

subtopic

numerical aperture

Transmission loss

dispersion

Optical fiber transmission mode

coherent light

incoherent light source

Photodiode

A method that uses the measured object to directly or indirectly change the intensity of the transmitted light in the optical fiber and then detects the measured object by measuring the change in light intensity.

The method of using external factors to change the phase of the light wave in the optical fiber and measuring the measured phase by detecting the phase change is called phase modulation.

Known for its high sensitivity.

blood sample monitoring

stroke analysis

Atherosclerosis analysis

Gas detection

medical endoscope

Fiber optic liquid level sensor