Laser Presentation System Using a Laser Pointer

US Patent #6761456

Nicolas BrownOct. 10, 2014

Problem Statement

Use of laser pointers during presentations presents a safety hazard if inadvertently directed towards the audience

Devise some way of disabling the laser when pointed away from the projector screen

Prior Art (1)

Proposed Solution: Only turn on the laser when it’s point at something bright (i.e. the projection screen)

Disadvantage: Hard to calibrate, easy to fool

Japanese Patent Application 2000-321530

Prior Art (2)

Proposed Solution: IR emitter placed on top of the projection screen; IR receiver on tip of laser pointer

Disadvantage: Emitted IR light could reflect off of audience, enabling the laser in their direction

Japanese Patent No. 2591667

Patent Design (1)

Proposed Solution: Laser (30) will only emit light when sensor (32) is illuminated by IR emitter (50) on projector (20)

Issued: July 2004

Patent Design (2)

What if the laser is flipped over??

No problem! Shutter will fall into place due to gravity when laser is inverted

Patent Design (3)

Other Variants:

Does this Problem Exist? According to medical literature: No…

“An ordinary laser pointer is safe, unless a user chooses to stare at its uncomfortable brilliant light for more than 10 seconds at close range” (Mainster et. al., 2004)

“In conclusion, laser pointers … if used appropriately are not an eye hazard, and even if used inappropriately will not cause permanent eye damage” (Marshall, 1998)

A 34 y/o male who stared into a 5 mW, 670 nm laser for 30-60 seconds suffered detectable macular injury but no loss in visual acuity (Luttrull and Hallisey, 1999)