Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
LASER ALARM
Document Type and Number:
Japanese Patent JPH0627237
Kind Code:
A
Abstract:

PURPOSE: To provide an outdoor laser alarm in which target detectable distance is increased as long as possible while preventing erroneous alarm due to outdoor environmental conditions.

CONSTITUTION: A pulse laser beam 6 is emitted from a laser driver 2 and projected through an optical transmitting section 7 under control of a controller 1a and reflected light enters through a detector 10 and an amplifier 12 into a comparator 13a. A plurality of reference voltages are prepared for the comparator 13a by a reference voltage generator 14. In prestage for beginning laser detection, noise level due to external environmental conditions such as mist is detected and a reference voltage slightly higher than the noise level is selected. This constitution ensures maximum detectable distance while preventing erroneous alarm due to external environment.


Inventors:
OKAMOTO YUJI
Application Number:
JP18020392A
Publication Date:
February 04, 1994
Filing Date:
July 08, 1992
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
NEC CORP
International Classes:
G01S17/08; (IPC1-7): G01S17/08
Attorney, Agent or Firm:
Naoki Kyomoto (2 outside)