LED lens

• US 8,556,452 B2
• Filed: 01/14/2010
• Issued: 10/15/2013
• Est. Priority Date: 01/15/2009
• Status: Active Grant

• Current Assignee: Ilumisys Incorporated (Altair Engineering Incorporated)
• Original Assignee: Ilumisys Incorporated (Altair Engineering Incorporated)
• Inventors: Simon, David L., Ivey, John, Lavering, Gordon R.
• Primary Examiner(s): Shallenberger, Julie
• Application Number:
  US12/687,519
• Publication Number:
  US 20100177532A1
• Time in Patent Office: 1,370 Days
• Field of Search: 362/217.02, 362/217.04, 362/217.05, 362/217.07, 362/217.08, 362/223
• US Class Current: 362/217.07
• CPC Class Codes: B29D 11/00278 Lenticular sheets B29D11/00269 takes precedence
• CPC Class Codes: F21K 9/27 Retrofit light sources for lighting devices with two fittings for each light source, e.g. for substitution of fluorescent tubes
• CPC Class Codes: F21K 9/68 Details of reflectors forming part of the light source
• CPC Class Codes: F21K 9/69 Details of refractors forming part of the light source
• CPC Class Codes: F21V 5/048 the lens being a simple lens adapted to cooperate with a point-like source for emitting mainly in one direction and having an axis coincident with the main light transmission direction, e.g. convergent or divergent lenses, plano-concave or plano-convex lenses
• CPC Class Codes: F21V 7/0083 Array of reflectors for a cluster of light sources, e.g. arrangement of multiple light sources in one plane combination of two or more reflectors F21V7/0025
• CPC Class Codes: F21V 7/0091 using total internal reflection
• CPC Class Codes: F21V 7/041 with conical or pyramidal surface
• CPC Class Codes: F21Y 2103/10 comprising a linear array of point-like light-generating elements
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 2924/1815 Shape
• CPC Class Codes: H01L 33/54 having a particular shape

Abstract

A light modifier for an LED producing light about a central axis is provided. The light modifier includes a lens defining an indentation. The indentation is angled relative to the central axis by an amount less than a complementary angle of a critical angle of the lens along the indentation. The lens can reduce the appearance of a bright spot created by the LED.

Claims

1. A light modifier for an LED producing light about a central axis, the light modifier comprising:

a lens defining an indentation to produce total internal reflection (TIR), the indentation angled relative to the central axis by an amount less than a complementary angle of a critical angle of the lens along the indentation such that light produced by the LED is at least substantially internally reflected by the indentation to pass through a light transmitting portion of the lens directly bordering an outer edge of the indentation to form a line of light, wherein;

the indentation is angled between approximately 15 and 25 degrees relative to the central axis such that two lines of light are formed along a length of the indentation when the LED produces the light and the light is reflected to pass through the light transmitting portion of the lens; and

the indentation includes two sidewalls forming a V-shape, each sidewall having one of the two lines of light formed along its outer edge.

2. The light modifier of claim 1, wherein the indentation is angled approximately 20 degrees relative to the central axis.

3. The light modifier of claim 1, wherein the entire indentation is angled a same degree relative to the central axis.

4. The light modifier of claim 1, wherein:

absent the lens, a distribution of the light produced by the LED in an area radial of the central axis includes a bright spot having a diameter,

the outer edge of the indentation is disposed in the area,

a width of the indentation at the outer edge is at least as large as the diameter of the bright spot produced by the LED, such that the indentation redistributes the light of the bright spot to pass through the light transmitting portion but creates a dark spot at the indentation, and

the indentation is angled such that a resulting distribution of the light produced by the LED in the area is substantially even across the indentation and the light transmitting portion.

5. The light modifier of claim 1, wherein a surface of the indentation is substantially smooth.

6. The light modifier of claim 1, further comprising a reflector within the indentation.

7. The light modifier of claim 1, wherein an outer surface of the lens outwardly extends from the outer edge of the indentation to a lower cover.

8. The light modifier of claim 7, wherein the outer surface is angled relative to a horizontal axis approximately between 70 and 80 degrees.

9. A replacement light for a fluorescent tube usable in a fluorescent fixture comprising:

a support structure having a longitudinal axis;

at least one LED connected to the support structure, the LED producing light about respective central axes;

at least one lens positioned along the central axis of the at least one LED to produce total internal reflection (TIR), the lens defining an indentation angled relative to the central axis less than a complementary angle of a critical angle of the lens along the indentation such that light produced by the at least one LED is at least substantially internally reflected by the indentation to pass through a light transmitting portion of the lens directly bordering an outer edge of the indentation to form a line of light, wherein;

the indentation is angled between approximately 15 and 25 degrees relative to the central axis such that two lines of light are formed along a length of the indentation when the at least one LED produces the light and the light is reflected to pass through the light transmitting portion of the lens; and

the indentation includes two sidewalls forming a V-shape, each sidewall having one of the two lines of light formed along its outer edge; and

at least one electrical connector at a longitudinal end of the support structure in electrical communication with the at least one LED.

10. The replacement light of claim 9, wherein the lens includes multiple indentations, each indentation positioned along the central axis of one of the at least one LEDs.

11. The replacement light of claim 10, wherein the lens includes integral Fresnel lenses between indentations.

12. The replacement light of claim 9, wherein the lens includes a single V-shaped indentation extending longitudinally a length of the lens.

13. The replacement light of claim 9, wherein the entire indentation is angled approximately 20 degrees relative to the axis.

14. The replacement light of claim 9, wherein the lens includes a light pipe around each indentation.

15. The replacement light of claim 14, wherein the light pipe includes a light diffuser on at least one of a top surface and a bottom surface thereof.

16. The replacement light of claim 14, wherein the light diffuser is more densely disbursed on at least one of the distal ends of the light pipe.

17. The replacement light of claim 14, wherein the at least one LED includes multiple LEDs and the light pipe is positioned over substantially all of the multiple LEDs.

18. The replacement light of claim 14, wherein the light pipe tapers from the indentation toward at least one of the distal ends of the light pipe.

19. The replacement light of claim 9, wherein an outer surface of the lens including the light transmitting portion outwardly extends from the outer edge of the indentation to a lower cover.

20. The replacement light of claim 19, wherein the outer surface is angled relative to a horizontal axis approximately between 70 and 80 degrees.

21. A method of forming a lens for an LED producing light about a central axis, the lens defining an indentation to produce total internal reflection (ITR) angled relative to the central axis less than a complementary angle of a critical angle of the lens along the indentation such that light produced by the LED is at least substantially internally reflected by the indentation to pass through a light transmitting portion of the lens directly bordering an outer edge of the indentation to form a line of light, wherein the indentation is angled between approximately 15 and 25 degrees relative to the central axis such that two lines of light are formed along a length of the indentation when the LED produces the light and the light is reflected to pass through the light transmitting portion of the lens and whereinthe indentation includes two sidewalls forming a V-shape, each sidewall having one of the two lines of light formed along its outer edge, the method comprising:

extruding material in an extrusion direction to form a sheet of greater width than the lens, the sheet having a same profile as the lens; and

sectioning the sheet to form the lens.

22. The method of claim 21, wherein sectioning the sheet including cutting the sheet perpendicular to the extruding direction.