Method of retrofitting a runway sign with a single LED lamp

• US 8,938,877 B2
• Filed: 01/17/2013
• Issued: 01/27/2015
• Est. Priority Date: 01/17/2013
• Status: Active Grant

• Current Assignee: OSRAM Sylvania Inc. (Ams-Osram AG)
• Original Assignee: OSRAM Sylvania Inc. (Ams-Osram AG)
• Inventors: Tessnow, Thomas, Albright, Kim, Boyd, Ronald E. Jr., Plaza, Aaron
• Primary Examiner(s): PHAN, THIEM D
• Application Number:
  US13/743,558
• Publication Number:
  US 20140196281A1
• Time in Patent Office: 740 Days
• Field of Search: 298/25, 294/020.1, 294/261, 294/28, 295/921, 362/217.01, 362/217.05, 362/217.17, 362/225, 362/240, 362/243, 362/245, 362/249, 362/800
• US Class Current: 29/825
• CPC Class Codes: B64F 1/002 Taxiing aids
• CPC Class Codes: Y10T 29/49117 Conductor or circuit manufacturing
• CPC Class Codes: Y10T 29/49718 Repairing
• CPC Class Codes: Y10T 29/49815 Disassembling
• CPC Class Codes: Y10T 29/49826 Assembling or joining

Abstract

A method of retrofitting an existing airfield runway sign with a single LED lamp. Light is produced by a linear array of white-light LEDs. A cylindrical lens is mounted longitudinally adjacent to the LEDs, and collects a central portion of the light emitted from the LEDs. A pair of inclined surfaces extend from the lateral edges of the LEDs to respective lateral edges of the cylindrical lens. The inclined surfaces have a rough surface texture and reflect light diffusely. The inclined surfaces collect a peripheral portion of the light emitted from the LEDs, and direct the reflected light toward the cylindrical lens. The LEDs, cylindrical lens and inclined surfaces are all mechanically supported by a heat sink. The replacement lamp is placed into a runway sign near its top or bottom edge, and illuminates both viewing surfaces of the runway sign simultaneously without a diffuser.

Claims

1. A method of retrofitting a two-sided airport runway sign (10) adjacent a runway, the runway sign (10) being rectangular in profile and emitting light through rectangular, translucent front and rear faces (11), the front and rear faces (11) being longitudinally separated by first and second opposing longitudinal edges (17, 16) and being perpendicular to the runway, the runway sign (10) including a plurality of original equipment lamps in its interior along the first and second longitudinal edges (17, 16) that are disposed in respective electrical sockets proximate the longitudinal edges (17, 16), the runway sign (10) also including a diffuser (130) in its interior adjacent one of the original equipment lamps, the method comprising:

opening the runway sign (10) to gain access to an interior of the runway sign (10);

electrically disengaging all the original equipment lamps on the first longitudinal edge (17) of the runway sign (10);

removing the diffuser (130) from the interior of the runway sign (10);

securing a single LED lamp (1) in one of said electrical sockets, the single LED lamp (1) having a plurality of spaced LEDs (2);

closing the runway sign (10) without reinstalling the removed diffuser (130) adjacent the single LED lamp (1);

energizing the single LED lamp (1) through the electrical socket to provide illumination to both the front and rear faces (11) of the runway sign (10) simultaneously without directing light through the diffuser (130), the illumination having average illuminance values between 108 and 323 lux at the front and rear faces (11); and

operating the runway sign (10) to guide aircraft on said runway.

2. The method of claim 1, wherein the single LED lamp (1) comprises:

a plurality of LEDs (2) spaced along a line parallel to an intersection of the first longitudinal edge (17) with the front face (11);

a cylindrical lens (4) that receives a central portion of light emitted from the LEDs (2); and

a pair of inclined reflecting surfaces (3) extending from an outer edge of the LEDs (2) to an outer edge of the cylindrical lens (4), the inclined reflecting surfaces (3) reflecting a peripheral portion of the light emitted from the LEDs (2) toward the cylindrical lens (4);

wherein the cylindrical lens (4) transmits the central portion and the reflected peripheral portion to form a light output.

3. The method of claim 2,

wherein the light output peaks along the front and rear faces (11) at locations proximate the second longitudinal edge (16) opposite said first longitudinal edge (17);

and

wherein the light output decreases monotonically to a minimum at the first longitudinal edge (17).

4. The method of claim 2, wherein the inclined reflecting surfaces (3) are diffuse reflectors.

5. The method of claim 2, wherein the LEDs (2) are white-light LEDs.

6. The method of claim 2, wherein the inclined reflecting surfaces (3) and the cylindrical lens (4) are devoid of wavelength conversion material.

7. The method of claim 2, wherein the cylindrical lens (4) alters the angular path of the transmitted light along a forward direction (Y) but not along a lateral direction (X).

8. The method of claim 1, wherein said electrically disengaging all the original equipment lamps comprises allowing at least one of the original equipment lamps to burn out.

9. The method of claim 1, wherein said electrically disengaging all the original equipment lamps comprises physically removing at least one of the original equipment lamps.

10. The method of claim 1, further comprising electrically disengaging all the original equipment lamps in the interior of the runway sign (10).

11. The method of claim 1, wherein the first longitudinal edge (17) of the runway sign (10) is the top edge of the runway sign (10).

12. The method of claim 1, wherein the first longitudinal edge (17) of the runway sign (10) is the bottom edge of the runway sign (10).