U.S. patent application number 10/278472 was filed with the patent office on 2004-04-29 for light collection assembly having mixed conic shapes for use with various light emitting sources.
Invention is credited to Chinniah, Jeyachandrabose, Patel, Balvantrai G., Sayers, Edwin M..
Application Number | 20040080835 10/278472 |
Document ID | / |
Family ID | 32069333 |
Filed Date | 2004-04-29 |
United States Patent
Application |
20040080835 |
Kind Code |
A1 |
Chinniah, Jeyachandrabose ;
et al. |
April 29, 2004 |
LIGHT COLLECTION ASSEMBLY HAVING MIXED CONIC SHAPES FOR USE WITH
VARIOUS LIGHT EMITTING SOURCES
Abstract
A lens assembly is disclosed for use with various light emitting
sources. The lens assembly includes a central section and an outer
section. The central section is radially centered on an optical
axis. The outer section radially surrounds the central section and
is radially centered on the optical axis. The outer section
includes an outer wall that has a generally rotated parabolic
shape, an inner wall that abuts the central section, and a slanted
front surface extending between the inner wall and the outer wall.
The front surface is the area of the lens assembly axially farthest
away from the light emitting source.
Inventors: |
Chinniah, Jeyachandrabose;
(Ann Arbor, MI) ; Sayers, Edwin M.; (Saline,
MI) ; Patel, Balvantrai G.; (Jacksonville,
FL) |
Correspondence
Address: |
VISTEON 29074
BRINKS HOFER GILSON & LIONE
P.O. BOX 10395
CHICAGO
IL
60611
US
|
Family ID: |
32069333 |
Appl. No.: |
10/278472 |
Filed: |
October 23, 2002 |
Current U.S.
Class: |
359/708 |
Current CPC
Class: |
F21Y 2115/10 20160801;
G02B 13/18 20130101; F21V 5/008 20130101; G02B 19/0028 20130101;
G02B 3/08 20130101; G02B 3/06 20130101; F21S 43/26 20180101; G02B
19/0061 20130101; F21V 5/045 20130101; G02B 3/02 20130101 |
Class at
Publication: |
359/708 |
International
Class: |
G02B 003/02; G02B
013/18 |
Claims
We claim:
1. A lens assembly for use with a light emitting source defining an
optical axis, the lens assembly comprising: a central section
radially centered on the optical axis; and an outer section
radially surrounding said central section and centered on the
optical axis, wherein said outer section has a generally rotated
parabolic shaped outer wall, an inner wall abutting said central
section, and a slanted front surface extending between said inner
wall and said outer wall.
2. The lens assembly of claim 1 wherein said inner wall is radially
centered on the optical axis.
3. The lens assembly of claim 1 wherein said inner wall is
generally cylindrical-shaped.
4. The lens assembly of claim 1 wherein said central section is a
spherical-elliptical lens.
5. The lens assembly of claim 4 wherein said central section has a
front surface and said central section front surface and said outer
section slanted front surface comprise a lens assembly composite
front surface, said lens assembly further comprising spreading
optics on any section of said composite front surface.
6. The lens assembly of claim 4 further comprising an outer
spreading optics assembly centered on the optical axis and axially
spaced apart from said central section and said outer section.
7. The lens assembly of claim 4 further comprising outer spreading
optics integral with said outer section outer wall.
8. The lens assembly of claim 1 wherein said central section is a
plano-convex aspheric condenser lens.
9. The lens assembly of claim 8 wherein said central section has a
front surface and said central section front surface and said outer
section slanted front surface comprise a lens assembly composite
front surface, said lens assembly further comprising spreading
optics on any section of said composite front surface.
10. The lens assembly of claim 8 further comprising an outer
spreading optics assembly centered on the optical axis and axially
spaced apart from said central section and said outer section.
11. The lens assembly of claim 8 further comprising outer spreading
optics integrated with said outer section outer wall.
12. The lens assembly of claim 1 wherein said central section is a
hyperbolic plane lens.
13. The lens assembly of claim 12 wherein said central section has
a front surface and said central section front surface and said
outer section slanted front surface comprise a lens assembly
composite front surface, said lens assembly further comprising
spreading optics on said composite front surface.
14. The lens assembly of claim 12 further comprising an outer
spreading optics assembly centered on the optical axis and axially
spaced apart from said central section and said outer section.
15. The lens assembly of claim 12 further comprising outer
spreading optics integral with said outer section outer wall.
16. The lens assembly of claim 1 wherein said central section is a
Fresnel lens.
17. The lens assembly of claim 16 wherein said central section has
a front surface and said central section front surface and said
outer section slanted front surface comprise a lens assembly
composite front surface, said lens assembly further comprising
spreading optics on any section of said composite front
surface.
18. The lens assembly of claim 16 further comprising an outer
spreading optics assembly centered on the optical axis and axially
spaced apart from said central section and said outer section.
19. The lens assembly of claim 16 further comprising outer
spreading optics integral with said outer section outer wall.
20. The lens assembly of claim 1 wherein said central section has a
front surface and said central section front surface and said outer
section slanted front surface comprise a lens assembly composite
front surface, said lens assembly further comprising spreading
optics on any section of said composite front surface.
21. The lens assembly of claim 1 further comprising an outer
spreading optics assembly centered on the optical axis and axially
spaced apart from said central section and said outer section.
22. The lens assembly of claim 1 further comprising outer spreading
optics integral with said outer section outer wall.
23. The lens assembly of claim 1 wherein said outer section is a
solid internally reflective lens having a spherical inner surface
extending between said central section and said outer wall.
24. The lens assembly of claim 1 wherein said outer wall is a
reflective surface and said slanted front surface is a corrective
lens.
Description
TECHNICAL FIELD
[0001] This invention relates generally to lighting systems and,
more specifically, to an efficient light collection assembly for
use with a light emitting source. The assembly according to the
present invention will find utility in vehicle lighting systems, as
well as in a variety of non-automotive illumination
applications.
BACKGROUND
[0002] It is known to use light emitting sources, including light
emitting diodes (LEDs), Lambertian emitters, 2 .pi. emitters, and
fiber optic light guide tips, in a variety of applications,
including, but not limited to, vehicular applications.
Specifically, LED sources are increasingly finding applications in
automotive, commercial, and general lighting applications since
their light outputs have increased exponentially and prices have
fallen significantly over the past few years. LEDs are attractive
due to their small size and the fact that they consume less power
relative to incandescent light sources. The popularity of LEDs as
light sources is expected to continue and increase as their
potential benefits are further developed, particularly with respect
to increased light output.
[0003] Today's LEDs come in different sizes and different emitting
cone angles. An emitting cone angle is typically referred to as 2
.phi.. LEDs emit light over a wide range of cone angles, ranging
from 15 degrees (forward emitting or side emitting) to 180 degrees
(hemispherical emitting). It is therefore very important to
construct efficient light collection assemblies to harness the
maximum possible light output from LEDs and direct it in a
predetermined controlled manner.
[0004] Thus, there is a need in the lighting systems field to
create an improved light collection device that can be used with
any type of LED to direct the light dispersion in a predetermined
manner. This invention provides such an improved LED light
collection device.
SUMMARY
[0005] The present invention addresses these requirements by
providing a lens assembly including a central section and an outer
section. The central section is radially centered on an optical
axis. The outer section radially surrounds the central section and
is centered on the optical axis. The outer section has a generally
rotated parabolic shaped outer wall, an inner wall that abuts the
central section, and a slanted front surface that extends between
the inner wall and the outer wall. The lens assembly of the present
invention can also be combined with beam spreading optic elements
such as pillows, flutes, and prisms.
[0006] An advantage of the lens assembly of the present invention
is that it redirects light into a predetermined pattern regardless
of the type of light emitting source used.
[0007] These and other aspects and advantages of the present
invention will become apparent upon reading the following detailed
description of the invention in combination with the accompanying
drawings.
BRIEF DESCRIPTION OF THE FIGURES
[0008] FIG. 1 is an axial view of a first embodiment of the present
invention;
[0009] FIG. 2 is a partial cross-sectional view taken along the
line 2-2 in FIG. 1;
[0010] FIG. 3 is a partial cross-sectional view of a second
embodiment of the present invention;
[0011] FIG. 4 is a partial cross-sectional view of a third
embodiment of the present invention;
[0012] FIG. 5 is a partial cross-sectional view of a fourth
embodiment of the present invention;
[0013] FIG. 6 is a partial cross-sectional view of a first
embodiment of the spreading optics;
[0014] FIG. 7 is a partial cross-sectional view of a second
embodiment of the spreading optics;
[0015] FIG. 8 is a partial cross-sectional view of a third
embodiment of the spreading optics;
[0016] FIG. 9 is an extended perspective view of FIG. 2;
[0017] FIG. 10 is a partial cross-sectional view of a second
embodiment of the outer section;
[0018] FIG. 11 is a partial cross-sectional view of a second
embodiment of the corrective lens;
[0019] FIG. 12 is a partial cross-sectional view showing the path
of the rays of light for one embodiment;
[0020] FIG. 13A is a partial cross-sectional view showing the path
of the rays of light for another embodiment; and
[0021] FIG. 13B is a partial cross-sectional view showing the path
of the rays of light for yet another embodiment.
DETAILED DESCRIPTION
[0022] As shown in FIGS. 1 and 2, the lens assembly of the present
invention is generally designated at 20. The lens assembly 20
includes a central section 24 and an outer section 26. Further, the
lens assembly 20 is used with a light emitting source 22 (seen in
FIG. 2). Although Light Emitting Diodes (LEDs) are shown in all the
figures, the lens assembly 20 can be used with a variety of
different light emitting sources 22, including, but not limited to,
LEDs, Lambertian emitters, 2 .pi. emitters, and fiber optic light
guide tips. The light emitting source 22 defines an optical axis
25. The lens assembly 22 is designed to be used with a variety of
types of light emitting sources to reflect and refract the light
rays so that they exit the lens assembly 20 collimated.
[0023] The widest diameter of the lens assembly 20, as measured by
the outer diameter of the outer section is approximately
ten-fifteen (10-15) millimeters. This small size allows the lens
assembly to be easily used with the types of light emitting sources
outlined above. Further, the lens assembly 20 is preferably molded
of acrylic, polycarbonate, or similar moldable materials.
[0024] The central section 24 of the lens assembly 20 is centered
on the optical axis 25. The outer section 26 radially surrounds the
central section and is also centered on the optical axis 25. When
viewed axially, as shown in FIG. 1, the central section 24 is
generally circular-shaped and the outer section 26 is generally
annular-shaped.
[0025] The central section 24 can be one of four different designs.
The first design, shown in FIG. 2, is a spherical-elliptical lens
24A. The second design, shown in FIG. 3, is a plano-convex aspheric
condenser lens 24B. The third design, shown in FIG. 4, is a
hyperbolic-plane lens 24C. The fourth design, shown in FIG. 5, is a
Fresnel lens 24D. The Fresnel optics can be either on the inner
side or the outer side.
[0026] The outer section 26 of the lens assembly has a generally
rotated parabolic shaped radial outer wall 28. A rotated parabola
is a regular parabola with a point source at its focal point. This
parabola is rotated about an axis normal to the plane of the
parabola through the focal point resulting in the rays being tilted
by the rotated angle.
[0027] The outer section 26 also includes a radial inner wall 29.
The inner wall 29 is radially centered on the optical axis and is
preferably generally cylindrical-shaped.
[0028] The inner wall 29, which extends between the inner section
24 and the slanted front surface 30, allows the overall thickness
of the lens assembly 20 to remain as small as possible. Thus, the
central section is axially offset from the slanted front surface.
This design feature allows the light rays 31 to reflect and refract
as necessary to end up collimated through both the central section
and the outer section, as shown in FIGS. 12, 13A and 13B.
[0029] The front surface 30 of the outer section is the area of the
outer section 26 that is axially farthest away from the light
emitting source 22. The front surface 30 of the outer section
extends between the inner wall 29 and the outer wall 28 and is
slanted from a cross sectional view, as shown in FIG. 2.
Specifically, the radial inner wall 29 ends axially closer to the
light emitting source 22 than the radial outer wall 28. From a
perspective view, as shown in FIG. 9, the slanted front surface 30
in combination with the outer wall 28 is generally bowl-shaped.
[0030] There are two embodiments of the lens assembly outer section
26. In a first embodiment, shown in FIGS. 2-5, the outer section
26A is a solid internally reflective lens. There is an inner
surface 32 of the solid lens that is axially nearest the light
emitting source 22. The inner surface 32 of the outer section 26 is
generally spherically-shaped. Further, the inner surface 32 extends
between the central section 24 and the outer wall 28.
[0031] In a second embodiment, shown in FIGS. 10-11, the outer
section 26B includes a reflective surface as the radial outer wall
28 and a corrective lens as the slanted front surface 30. The
corrective lens can be either a continuous slanted front surface
130A, shown in FIG. 10, or it can be a stepped slanted front
surface 130B, shown in FIG. 11. An advantage of the stepped slanted
front surface 130B is that the rays of light are refracted to
collimate exactly as with the continuous slanted front surface
130A, but with a thinner lens than the continuous slanted front
surface 130A.
[0032] For all of the possible combinations, the inner section and
the outer section can be either a unitary component or they can be
separate components that attach to each other via conventional
means.
[0033] Spreading optics 34 may also be incorporated into the lens
assembly 20. Some specific examples of spreading optics include,
but are not limited to, pillows, flutes and prisms. Spreading
optics are designed to disperse light beams in a predetermined
manner. Depending on the application criteria, some designs could
spread the light horizontally, while other designs could be limited
to spreading the light vertically. Further, there are spreading
optics that can spread the light in all directions.
[0034] There are a variety of arrangements for incorporating the
spreading optics 34 into the lens assembly 20. In one embodiment,
shown in FIG. 6, the spreading optics 134 are integral with the
composite front surface 38 of the lens assembly 20. The composite
front surface 38 of the lens assembly 20 includes the slanted front
surface 30 of the outer section 26 and the front surface 36 of the
center section 24. The spreading optics 34 can be on just the outer
section 26, just the central section 24 or on the composite front
surface 38.
[0035] In a second embodiment, shown in FIG. 7, the spreading
optics 234 are axially spaced apart from the central section 24 and
the outer section 26.
[0036] In a third embodiment, shown in FIG. 8, the spreading optics
334 are integral with the outer section outer wall 28.
[0037] As any person skilled in the art of lens assemblies will
recognize from the previous detailed description and from the
figures and claims, modifications and changes can be made to the
preferred embodiments of the invention without departing from the
scope of this invention defined in the following claims.
* * * * *