US Patent No. 9,223,193

PROJECTION TYPE DISPLAY APPARATUS AND METHOD OF COOLING LIGHT SOURCE


Patent No. 9,223,193
Issue Date December 29, 2015
Title Projection Type Display Apparatus And Method Of Cooling Light Source
Inventorship Hiroshi Kato, Tokyo (JP)
Assignee NEC DISPLAY SOLUTIONS, LTD., Tokyo (JP)

Claim of US Patent No. 9,223,193

1. A display apparatus for projecting a beam from an LED to display an image, the display apparatus comprising:
a cooler that cools said LED;
a light detector that detects brightness of a surrounding area;
a voltage detector that detects a forward voltage of said LED;
a current detector that detects a forward current of said LED;
a temperature detector that detects a case temperature which represents a temperature of a case of said LED; and
a controller that adjusts brightness of said LED based on the brightness of the surrounding area and adjusts an amount of
cooling power of said cooler based on said forward voltage, said forward current, and said case temperature,

wherein said controller calculates a ratio of a difference between a predetermined maximum junction temperature and said case
temperature to a difference between a junction temperature of said LED and said case temperature, based on said forward voltage,
said forward current, and said case temperature.