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.
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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
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Current flicker metrics
• Simple
– Percent Flicker – Flicker Index
• Complex
– RPI LRC ASSIST – IEC PST – SVM – IEEE
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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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