A pair of similar white and grey electronics enclosures (2024.ep.28.1 and 2024.ep.28.2) with aluminum front faces. 2024.ep.28.2, labelled “Dutch 2” has stenciled lettering indicating various features in the front face. These are unlabelled on 2024.ep.28.1 (“Dutch 1”).
Each face has two RCA-type jacks near the horizontal center line. These are labelled “Control” and “Output” on Dutch 2. On the upper-right quadrant of the faces is a power switch and a power indicator light.
On the rear faces of the units are power cords, fuses, and two additional jacks, one red, one black.
A single grey cord ending in a three-pin plug is attached to the outputs of both units.
Accession Number: 2024.ep.28.1-2
Alternative Name:
Primary Materials: Iron Aloy, Plastic
2024.ep.28.1: A masking tape label on the upper left of the front console reads “DUTCH 1”. The leftmost jack is masking tape marked “C”. The rightmost jack is masking tape marked “LEFT// B [illegible writing below this]”.
A metal tag on the lower left of the front console reads: “INSTITUUT VOOR// ZINTUIGFYSIOLOGIE// RVO-TNO// No PLATO 5”
2024.ep.28.2: A masking tape label on the upper left of the front console reads “LCD DRIVER// DUTCH 2”. The leftmost jack is masking tape marked “D”. The rightmost jack is masking tape marked “Right// A// Blue”.
A metal tag on the upper left of the front console reads: “INSTITUUT VOOR// ZINTUIGFYSIOLOGIE// RVO-TNO// No PLATO 3”
(Each Enclosure): Height = 11, Width = 14, Length = 20.5.
These units are high voltage power supplies for prototype versions of the visual occlusion spectacles created by Dr. Paul Milgram. Each unit supplied a square wave signal based on a timing signal from an external sources. One circuit was used for each liquid Crystal Cell, thus both unites were used to operate one set of spectacles.
The circuits in good cosmetic condition and are functional. The enclosures are somewhat dirty.
Associated Instruments:
Dr. Paul Milgram; Organization for Applied Scientific Research of the Dutch National Defence Research Organisation.
Date of Manufacture: c. 1985
This item was among a small collection of items related to the development of the PLATO visual occlusion goggles donated to the collection by Dr. Paul Milgram on September 11, 2024.
John W. Senders, Kristofferson A. B., Levison W. H., Dietrich C. W., Ward J. L. (1967). The attentional demand of automobile driving. Highway Research Record, 195, 15–32. (Archived March 5. 2025).
Paul Milgram and R Van der Horst. “Alternating-Field Stereoscopic Displays Using Light-Scattering Liquid Crystal Spectacles.” Displays 7, no. 2 (1986): 67–72.
The PLATO (Portable Liquid crystal Apparatus for Tachistoscopic Occlusion) system was developed beginning around 1981 by Professor Paul Milgram. The system is an experimental tool that permits the time controlled occlusion of one or both of a subject’s eyes. The system has various applications, including research in visual perception, neuroscience, sports psychology/training, ergonomic evaluation of interfaces, etc., in addition to its original goal for quantifying the attentional workload of various tasks.
Visual occlusion was pioneered by Dr. John Senders and collaborators in the 1960’s (cited and linked above). Milgram completed his PhD under Senders at UofT in 1980. During his post-doc research, he focused on driving tasks, as Senders had done. This research was done while working at the Institute for Perception of the Dutch Organization for Applied Scientific Research (subsequently TNO Human Factors) in Soesterberg, the Netherlands.
These power supplies were likely used to drive the earliest units.
At that point, visual occlusion research relied on head mounted mechanical visors, first developed by Senders, to periodically block vision. While at TNO, Milgram developed a goggle-based system using cholesteric liquid crystals to block vision. This was proposed as an alternative to existing twisted-nematic liquid crystal devices and PLZT ceramic-based shutters. In addition to the need for light polarising layers, which significantly reduced the intensity of light transmitted, the former had a relatively slow refresh rate while the latter required very high voltages.
Milgram returned to Toronto in 1986 to take a faculty position at the Department of Industrial Engineering (currently Mechanical and Industrial Engineering) of the University of Toronto. In 1990, in Toronto, he founded Translucent Technologies Inc., which continues to develop and sell the PLATO system worldwide.
Models
- Donated to UTSIC