Light Emitting Diodes as a Rapid Visual Display for Use in Psychological Experiments

Scientific Research
Publication Type:
Journal Article
Optics and Photonics Journal, 2013, 3 (1), pp. 93 - 97
Issue Date:
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In this paper we show how light emitting diodes (LEDs) can be used in conjunction with existing display technologies as a means for achieving ultra-rapid visual stimulus exposure durations. We review existing rapid visual display meth-ods, and show how our apparatus overcomes the limitations inherent with each technique. Our apparatus, the LED tach-istoscope, takes advantage of the fast-switching times and high-brightness capabilities of LEDs in order to present sti- muli at previously unachievable durations as rapid as 1 ms. The rapid exposure durations are achieved by external LED backlight illumination of images on a liquid crystal display (LCD) after the components of the LCD have stabilized. This ensures that stimulus onset and offset are discrete. Furthermore, the fast-switching of the LEDs enables stimuli to be revealed for very rapid durations. The paper also describes studies in which the LED tachistoscope has already been applied, and offers suggestions for other possible applications. Interestingly, in our studies we show that the human visual system is very adept at extracting information with only very minimal stimulus exposure durations. Such studies have not been possible with existing display equipment. The LED tachistoscope opens up avenues for a variety of psy-chological and physiological experiments and provides a means for revealing the limits of human visual perception.
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