Method and system for LED based incandescent replacement module for railway signal

Patent metadata

Field	Value
Publication number	US-10173701-B2
Application number	US-201514964873-A
Country	US
Kind code	B2
Filing date	Dec 10, 2015
Priority date	May 27, 2015
Publication date	Jan 8, 2019
Grant date	Jan 8, 2019

Abstract

An apparatus including a housing; a solid state light source disposed in the housing to emit light therefrom; and a filter disposed in or on the housing in optical communication with the solid state light source to reshape a radiometric spectrum of the light emitted by the solid state light source to substantially replicate a radiometric spectrum of an incandescent filament light source.

First claim

What is claimed is:

1. An apparatus comprising:
a housing;
a solid state light source disposed in the housing to emit light therefrom; and
a filter disposed in or on the housing in optical communication with the solid state light source to reshape a radiometric spectrum of the light emitted by the solid state light source to substantially replicate a radiometric spectrum of an incandescent filament light source;
wherein the filter has a normalized optical intensity transmission ratio of 0.35-0.45 at about 450 nm, 0.65-0.75 at about 480 nm, 0.40-0.60 between about 520 nm and about 580 nm, 0.65-0.75 at about 600 nm, and greater than 0.7 at about 640 nm.

2. The apparatus of claim 1 , wherein the solid state light source comprises one LED or multiple LEDs or a Chip-On-Board (COB) LED array.

3. The apparatus of claim 1 , wherein the solid state light source comprises a warm white LED.

4. The apparatus of claim 3 , wherein the solid state light source comprises a warm white LED having a color temperature of about 2800 K.

5. The apparatus of claim 1 , wherein the filter compensates for radiometric spectrum differences between the light emitted by the solid state light source and light emitted from an incandescent filament light source.

6. The apparatus of claim 5 , wherein the filter further compensates for radiometric spectrum differences between the light emitted by the solid state light source and light emitted from an incandescent filament light source and further transmitted through a lens located in or on the housing.

7. The apparatus of claim 1 , further comprising a conical or frusto-conical reflector disposed between the solid state light source and the filter to enhance optical efficiency.

8. The apparatus of claim 7 , wherein the reflector comprises a curved parabolic shape.

9. The apparatus of claim 7 , wherein the reflector comprises an inner surface to reflect light from the solid state light source, the inner surface having a finish including at least one of a specular finish, a frosted finish, and micro-facets.

10. The apparatus of claim 7 , wherein the reflector comprises, at least in part, thermally conductive materials, to provide a heat sink for the solid state light source.

11. The apparatus of claim 7 , wherein the reflector has a red inner reflective surface and the filter is colored red.

12. The apparatus of claim 1 , wherein the filter is characterized by the following transfer function:

{

f

White
⁢

⁢
LEd
⁢

⁢
Device

⁡

(
λ
)

·

f

Color
⁢

⁢
Filtering

⁡

(
λ
)

=

f
Incandescent

⁡

(
λ
)

400
⁢

⁢
nm

≤
λ
≤

700
⁢

⁢
nm

where λ is an optical intensity spectral unit in nanometers (nm) and f refers to a spectral function.

13. The apparatus of claim 1 , further wherein the solid state light source comprises multiple LEDs including an array of LEDs disposed on a printed circuit board in electrical communication with the solid state light source.

14. The apparatus of claim 1 , further comprising a power supply electrically coupled to the solid state light source, wherein the power supply can operatively matingly interface with an electrical connection of a railway signal without a need to modify the railway signal.

15. An apparatus comprising:
a housing;
a solid state light source disposed in the housing to emit light therefrom; and
a filter disposed in or on the housing in optical communication with the solid state light source to reshape a radiometric spectrum of the light emitted by the solid state light source to substantially replicate a radiometric spectrum of an incandescent filament light source;
wherein the filter compensates for radiometric spectrum differences between the light emitted by the solid state light source and a light emitted from an incandescent filament light source, and wherein the filter further compensates for radiometric spectrum differences between the light emitted by the solid state light source and a light emitted from an incandescent filament light source and further transmitted through a colored lens located in or on the housing;
wherein the colored lens has a color selected from the group consisting of: blue, red, green, yellow, white, magenta/violet, and cyan.

16. An apparatus comprising:
a housing;
a solid state light source disposed in the housing to emit light therefrom; and
a filter disposed in or on the housing in optical communication with the solid state light source to reshape a radiometric spectrum of the light emitted by the solid state light source to substantially replicate a radiometric spectrum of an incandescent filament light source;
wherein the filter has an optical transmittance spectrum defined by a low transmittance region

Assignees

• Ge Lighting Solutions Llc

Inventors

• Fan Yu Felix
• Tavernese Luigi
• Urtiga Lucas
• Dubuc Eden

Classifications

• F21Y2105/16

  square or rectangular, e.g. for light panels · CPC title

• B61L5/1845 Primary

  Optical systems, lenses · CPC title

• F21V9/08

  for producing coloured light, e.g. monochromatic; for reducing intensity of light (with provision for controlling the colour F21V9/40) · CPC title

• B61L2207/02

  using light-emitting diodes [LEDs] · CPC title

• F21K9/23

  Retrofit light sources for lighting devices with a single fitting for each light source, e.g. for substitution of incandescent lamps with bayonet or threaded fittings · CPC title