Optical signal transmitter

• US 4,234,967 A
• Filed: 10/20/1978
• Issued: 11/18/1980
• Est. Priority Date: 10/20/1978
• Status: Expired due to Term

• Current Assignee: 3M Company
• Original Assignee: 3M Company
• Inventors: Henschel, John P.
• Primary Examiner(s): Griffin, Robert L.
• Assistant Examiner(s): Coles, Edward L.
• Application Number:
  US05/952,959
• Time in Patent Office: 760 Days
• Field of Search: 340/34, 250/199, 325/151, 325/185, 325/186, 307/10 BP, 307/10 LS, 307/126, 307/157, 320/9
• US Class Current: 398/106
• CPC Class Codes: G08C 23/04 using light waves, e.g. infrared
• CPC Class Codes: G08G 1/087 Override of traffic control, e.g. by signal transmitted by an emergency vehicle

Abstract

An optical signal transmitter for use by priority vehicles for remotely controlling traffic signals, including a light source which is flashed at a controlled repetition rate to transmit an optical signal to a receiver located at the traffic intersection. Circuitry associated with the light source includes a comparator network for disabling an electrical energy supply in the event of certain predetermined operating conditions.

Claims

1. An optical signal transmitter having,

a light source for converting stored electrical energy into light energy in response to a trigger signal,

trigger means for providing a trigger repetition rate signal having a controlled repetition rate,

electrical energy storage means, and

electrical energy supply means for supplying electrical energy to said electrical energy storage means;

wherein the improvement comprises

means for disabling said electrical energy supply means in response to a disable signal,

means for generating a reference signal,

means for generating an input signal indicative of a measured operating condition, and

means for comparing said reference signal with said input signal to generate said disable signal for controlling said electrical energy supply means such that said light source is operable only under predetermined operating conditions.

2. The optical signal transmitter of claim 1 wherein said input signal generating means comprises

circuit means for indicating the amount of energy stored in said electrical energy storage means, to disable said electrical energy supply means when the energy stored exceeds a predetermined value.

3. The optical signal transmitter of claim 1 wherein said optical signal transmitter is connected to a vehicle having an electrical system and wherein said input signal generating means comprises

circuit means for indicating the vehicle input voltage, to disable said electrical energy supply means when an over-voltage condition is present in the vehicle'"'"'s electrical system.

4. An optical signal transmitter having,

a light source for converting stored electrical energy into light energy in response to a trigger signal,

trigger means for providing a trigger repetition rate signal having a controlled repetition rate,

electrical energy storage means, and

electrical energy supply means for supplying electrical energy to said electrical energy storage means;

wherein the improvement comprises

means for disabling said electrical energy supply means in response to a disable signal,

means for generating an input signal responsive to said trigger repetition rate signal to disable said electrical energy supply means when a trigger signal is generated,

means for comparing said reference signal with said input signal to generate said disable signal for controlling said electrical energy supply means such that said light source is operable only under predetermined operating conditions.

5. An optical signal transmitter, comprising:

a gas discharge light source for converting stored electrical energy into light energy in response to a trigger signal;

a trigger repetition rate generator coupled to said gas discharge light source for providing a trigger signal having a controlled repetition rate;

a capacitor coupled to said gas discharge light source to provide electrical energy storage;

an electrical energy supply coupled to said capacitor;

a disable circuit coupled to said electrical energy supply responsive to a disable signal;

a regulated power supply producing a reference signal; and

a comparator coupled to said trigger repetition rate generator comparing said reference signal to an input signal indicative of a measured operating condition to generate said disable signal based upon said comparison;

whereby said gas discharge light source is operable only under predetermined operating conditions.

6. An optical signal transmitter as in claim 5 wherein said measured operating condition is the amount of energy stored in said capacitor wherein said disable signal is generated when the energy stored exceeds a predetermined value.

7. An optical signal transmitter as in claim 5 wherein said optical signal transmitter is mounted on a vehicle having an electrical system and wherein said measured operating condition is the voltage of said electrical system of said vehicle wherein said disable signal is generated when said voltage exceeds a predetermined value.

8. An optical signal transmitter of claim 5 wherein said measured operating condition is said trigger signal wherein said disable signal is generated when said trigger signal is provided.