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CANDELA-7308 Flicker Measurement Device
 

Definition

- Flicker
Perception of visual unsteadiness induced by a light stimulus whose luminance or spectral distribution fluctuates with time, for a static observer in a static environment. ~0-80Hz

- Phantom Array

Perception of a spatially extended series of light spots when making a saccade (image transition across the retina) across a light source that fluctuates with time. ~50Hz-2kHz

- Stroboscopic Effects

Change in motion perception induced by a light stimulus whose luminance or spectral distribution fluctuates with time, for a static observer in a non-static environment. ~50Hz-2kHz

- Temporal Light Artifact
An undesired change in visual perception, induced by a light stimulus whose luminance or spectral distribution fluctuates with time, for an observer in a certain environment.


 

Sources of TLA

1. Source voltage changes (noise)
2. Externally coupled noise sources
3. Dimmer phase angle instabilities (when dimming)
4. Driver instabilities
5. Driver (intended) operation


 

Current flicker metrics

• Simple

– Percent Flicker
– Flicker Index

• Complex

– RPI LRC ASSIST
– IEC PST
– SVM
– IEEE


 
 

Uses of Flicker Index and Percent Flicker


• Poor indicator of perceivable flicker
– But, could be used to compare lamps with similar characteristics (operating frequency)
• Energy Star Lamps specification
– Values are to be reported only; no limit
• California Title 24 Joint Appendix (JA) 8
– Percent Flicker must be <30% at <200Hz


 


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