Photo-Source (OLED)& Photo-sensor (pTFT)

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SUMMARY

The discussion focuses on calculating the illuminance sensed by a polysilicon-TFT light sensor from an OLED light source. The light source emits luminance measured in cd/m², while the sensor measures illuminance in lux. The user seeks to understand the relationship between the light emitted in steradians and the resulting lux reading on the sensor, specifically questioning the emission direction and steradian values. The calculations presented indicate that if the OLED emits 10 cd in all directions, the illuminance on a 100x100 µm sensor can be derived using the formula for lumens and lux.

PREREQUISITES
  • Understanding of luminance (cd/m²) and illuminance (lux) metrics
  • Knowledge of light emission concepts, including steradians
  • Familiarity with the relationship between lumens and lux
  • Basic principles of photometry and light sensor operation
NEXT STEPS
  • Research the principles of photometry and how to calculate illuminance from luminance
  • Learn about the geometry of light emission and the concept of steradians
  • Explore the characteristics and specifications of polysilicon-TFT light sensors
  • Investigate the effects of light source area on sensor readings and calculations
USEFUL FOR

Engineers, physicists, and researchers involved in optical sensor design, photometry, and illumination engineering will benefit from this discussion.

niikos
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Hello to everybody. This is my first post.

I have a trouble calculating the light illuminance that senses a light sensor.

Analytically. I have a light source (OLED) that is at the same surface as the light sensor (polysilicon-TFT). Also, the emitting area of the source is three or four times larges that the area of the senor. For the light source it is given the luminance from a figure of cd/m^2 to Voltages applied to it. For the light-sensor i have a equation that uses lux (lx) to calculate the production of current from it.
I need to calculate how much of light (in lux) is sensing the light-sensor from the light source. (assuming that there isn't another light source)

1st Question: The light source is emmitting light to any direction or only straight forward?
2nd : if straightforward what is the steradian of the emmition? (if it is at any direction, the steredian of the emmition is 2pi)
3rd : depending of the answer of the 1st question, is the light-sensor sensing any light?

So,
I know that cd/m^2=lm/m^2.sr=lux/sr. if the steradian of the light source is 2pi and the emmitting light luminance is A cd/m^2 the sensed light illumination of the sensor is A*2pi ? Am i right?
 
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If the source gives 10cd of light to any direction. A sensor of area 100x100um how many lux does it read?

So, the lumens are 10*4pi lm , and the illuminance: 10*4pi/(100um*100um) lux?
Am i right?
 

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