Overlapping strobe flash pattern

• US 5,644,291 A
• Filed: 06/22/1995
• Issued: 07/01/1997
• Est. Priority Date: 05/04/1995
• Status: Expired due to Fees

• Current Assignee: Federal Signal Corporation
• Original Assignee: Federal Signal Corporation
• Inventors: Jozwik, Jacek J.
• Primary Examiner(s): Mullen, Thomas
• Assistant Examiner(s): GOINS, DAVETTA WOODS
• Application Number:
  US08/493,684
• Time in Patent Office: 740 Days
• Field of Search: 340/472, 340/471, 340/659, 340/478, 340/331, 340/332, 340/932, 340/908, 340/908.1, 340/468, 340/469, 340/474, 362/74, 362/251
• US Class Current: 340/472
• CPC Class Codes: B60Q 1/2611 Indicating devices mounted on the roof of the vehicle

Abstract

A system and method for generating and broadcasting emergency lighting signals wherein the lights are synchronized such that when a first light is energized with a packet of short, rapid bursts, a second light begins to flash before the first light is de-energized. Control circuitry connected to the power source selectively controls the packetized energization of the light sources and includes timing circuitry for periodically energizing a first of the light sources for a first duration and for energizing a second of the light source for a second duration. The second duration overlaps, but is not coincident with the first duration in a repeating pattern such that the first and second sources are periodically energized simultaneously before the first source is de-energized.

Claims

1. An emergency signalling system comprising:

two or more light sources emitting light;

a modulator coupled to the light sources for modulating the light from each of the sources between relatively low and high states of brightness to create a visual pattern from each of the light sources of cyclically flashing light, a controller connected to the modulator for controlling transitions of the light from one of the states to the other, and the controller including means for synchronizing the flashing lights from the two or more light sources such that the transition of brightness from the high to the low state in one of the light sources appears to visually overlap the transition of brightness from the low to the high state in another of the two or more light sources.

2. The system of claim 1 wherein the modulator modulates the lights such that the high state of brightness comprises an energized state and the low state of brightness comprises a de-energized state.

3. The system of claim 2 wherein the light sources are strobe tubes, and the modulator includes means for applying a pulse packet to the light source for selective energization thereof according to signals from the controller.

4. The system of claim 1 wherein the controller includes a microprocessor.

5. The system of claim 1 wherein the controller includes a memory having information stored therein representing at least one illumination pattern.

6. The system of claim 1 wherein the modulator modulates the lights such that the high state of brightness corresponds to a first output color and the low state of brightness corresponds to a second output color.

7. The system of claim 1 wherein the modulator modulates the lights such that the high state of brightness corresponds to a first intensity level and the low state of brightness corresponds to a second intensity level.

8. The system of claim 1 wherein the modulator modulates the lights such that the high state of brightness corresponds to a first color at a first intensity and the low state of brightness corresponds to a second color at a second intensity.

9. An emergency signalling system comprising:

two or more light sources for radiating light in response to application of power from a source of power, a switching network between the two or more light sources and the source of power for selectively energizing the light sources to generate flashes of light from each of the sources, and a controller for controlling the selective energization of the two light sources such that an ending of a flash from a first of the light sources appears to visually overlap the beginning of a flash from a second of the light sources.

10. The system of claim 9 wherein at least one of the light sources comprises a strobe tube, and further comprising driving circuitry connected to the controller for applying pulse packets to the strobe tube according to signals from the controller for selective energization thereof.

11. A method of generating emergency signals, comprising the steps of:

broadcasting light from at least first and second light sources;

modulating each of the first and second light sources to broadcast light therefrom in a periodic visual pattern that transitions between at least relatively low and high states of brightness; and

synchronizing the periodic visual pattern of the first and second light sources so that each transition of brightness of the light sources occurs between two sequential transitions of the light from the other light source.

12. The method of claim 11 wherein the step of synchronizing the modulation of the first and second light sources provides a periodic pattern in which the first light source is modulated from the second state of brightness to the first state of brightness before the light of the second light source is modulated to the second state of brightness.

13. The method of claim 11 wherein the step of modulating the first and second light sources between the first and second states of brightness comprises the steps of energizing and de-energizing each of the light sources.

14. The method of claim 13 wherein the step of energizing the light sources comprises the steps of generating pulse packets of driving signals, and applying the pulse packets to the light sources.

15. The method of claim 11 wherein the step of modulating the first light source between a first and a second state of brightness comprises the step of adjusting the output intensity of a continuous light.

16. The method of claim 15 wherein the duration of the first state of brightness for at least one of the light sources is substantially equal to the duration of the second state of brightness whereby the modulation between states has approximately a fifty percent duty cycle.

17. The method of claim 11 wherein the step of modulating the first light source between first and second states of brightness comprises the step of adjusting the output color to provide light at first and second output colors.

18. The method of claim 11 wherein the step of modulating the first and second light sources comprises the step of accessing a memory to obtain information for adjusting the states of brightness thereof.

19. A method of increasing the effectiveness of an emergency lighting system, comprising the steps of energizing and de-energizing first and second lamps to broadcast light therefrom in a fashion of alternating flashes, and synchronizing the alternating flashes of the first and second lamps to visually overlap such that the second lamp is energized before the first lamp is de-energized and the first and second light sources are de-energized at different times.