U.S. patent number RE34,254 [Application Number 07/714,226] was granted by the patent office on 1993-05-18 for surface mounted led package.
This patent grant is currently assigned to Dialight Corporation. Invention is credited to Daniel Dragoon.
United States Patent |
RE34,254 |
Dragoon |
May 18, 1993 |
Surface mounted LED package
Abstract
The surface mounted LED package disclosed herein includes an LED
having a first surface, a second surface opposite to the first
surface, two electrical contacts on the first surface, and a light
emitting portion in the second surface; a housing mounted on the
LED and having a generally rectangular parallelepipedal shape, a
first passageway extending from a first surface of the housing part
way through the housing, the first passageway being sized, shaped,
and positioned to receive the second surface of the LED such that
the light emitting portion of the second surface faces into the
first passageway, and a second passageway extending from a second
surface of the housing to a third surface of the housing and
communicating with the first passageway; and a lens received in the
second passageway and having a first radiating surface located
outside the housing and an internal reflecting surface located
inside the housing above the light emitting portion of the LED in
position to reflect light from the light emitting portion of the
LED toward the radiating surface.
Inventors: |
Dragoon; Daniel (Fairfield,
CT) |
Assignee: |
Dialight Corporation
(Manasquan, NJ)
|
Family
ID: |
27023747 |
Appl.
No.: |
07/714,226 |
Filed: |
June 12, 1991 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
417469 |
Oct 5, 1989 |
04935856 |
Jun 19, 1990 |
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Current U.S.
Class: |
362/307;
362/800 |
Current CPC
Class: |
F21V
19/005 (20130101); H01L 33/486 (20130101); H05K
3/301 (20130101); F21W 2111/00 (20130101); H01L
2924/0002 (20130101); H01L 2924/0002 (20130101); H01L
2924/00 (20130101) |
Current International
Class: |
F21K
7/00 (20060101); F21V 19/00 (20060101); H01L
33/00 (20060101); H05K 3/30 (20060101); E21V
007/00 () |
Field of
Search: |
;362/307,362,800 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Cerled Advertising Flyer--CSE Series, SMD--Side Looker LED, Sep.
1990..
|
Primary Examiner: Ostrager; Allen M.
Attorney, Agent or Firm: Oblon, Spivak, McClelland, Maier
& Neustadt
Claims
What is claimed as new and desired to be secured by Letters Patent
of the United States is:
1. A surface mounted LED package comprising:
(a) an LED having;
(i) a first surface;
(ii) a second surface opposite to said first surface;
(iii) two electrical contacts on said first surface; and
(iv) a light emitting portion in said second surface;
(b) a housing mounted on said LED, said housing having:
(i) a generally rectangular parallelepipedal shape;
(ii) a first passageway extending from a first surface of said
housing part way through said housing, said first passageway being
sized, shaped, and positioned to receive said second surface of
said LED such that said light emitting portion of said second
surface faces into said first passageway; and
(iii) a second passageway extending from a second surface of said
housing to a third surface of said housing and communicating with
said first passageway; and
(c) a lens received in said second passageway, said lens
having:
(i) a radiating surface located outside said housing and
(ii) an internal reflecting surface located inside said housing
above said light emitting portion of said LED in position to
reflect light from said light emitting portion of said LED toward
said radiating surface.
2. A surface mounted LED package as recited in claim 1 and further
comprising an opaque reflecting material located in said second
passageway adjacent said internal reflecting surface.
3. A surface mounted LED package as recited in claim 1 wherein:
(a) said first passageway and said second passageway are
perpendicular to each other and
(b) said internal reflecting surface of said lens is disposed at
45.degree. to both said first passageway and said second
passageway. .[.4. A surface mounted LED package as recited in claim
1 wherein:
(a) said housing has a slot in its front surface extending from its
second surface to its third surface and
(b) said first passageway communicates with said slot..]. .[.5. A
surface mounted LED package as recited in claim 4 wherein said slot
is located at the center of the edges of said second and third
surfaces joining said
first surface..]. 6. A surface mounted LED package as recited in
claim 1 wherein said first passageway guides and reflects light
from said LED to a
light collecting surface of said lens. 7. A surface mounted LED
package as recited in claim 6 wherein said second passageway has a
cross section
sized and shaped to accept said lens. 8. A surface mounted LED
package as recited in claim 1 wherein said second passageway has a
cross section
sized and shaped to accept said lens. .Iadd.9. A surface mounted
LED package as recited in claim 1 wherein:
(a) said housing has a slot in its first surface extending from its
second surface to its third surface and
(b) said first passageway communicates with said slot. .Iaddend.
.Iadd.10. A surface mounted LED package as recited in claim 9
wherein said slot is located at the center of the edges of said
second and third surfaces
joining said first surface. .Iaddend. .Iadd.11. A surface mounted
LED package comprising:
(a) an LED having:
(i) a first surface;
(ii) a second surface opposite to said first surface;
(iii) two electrical contacts; and
(iv) a light emitting portion;
(b) a housing mounted on said LED, said housing having:
(i) a first passageway extending from a first surface of said
housing part way through said housing, said first passageway being
sized, shaped, and positioned to receive said second surface of
said LED such that said light emitting portion of said LED faces
into said first passageway, and
(ii) a second passageway extending from a second surface of said
housing at least part way through said housing and communicating
with said first passageway; and
(c) a lens received in said second passageway, said lens
having:
(i) a radiating surface and
(ii) an internal reflecting surface located inside said housing in
position to reflect light from said light emitting portion of said
LED toward said radiating surface. .Iaddend. .Iadd.12. A surface
mounted LED package as recited in claim 11 and further comprising
an opaque reflecting material located in said second passageway
adjacent said internal reflecting surface. .Iaddend. .Iadd.13. A
surface mounted LED package as recited in claim 11 wherein:
(a) said first passageway and said second passageway are
perpendicular to each other and
(b) said internal reflecting surface of said lens is disposed at
45.degree. to both said first passageway and said second
passageway. .Iaddend. .Iadd.14. A surface mounted LED package as
recited in claim 11 wherein:
(a) said housing has a slot in its first surface extending from its
second surface to a third surface of said housing and
(b) said first passageway communicates with said slot. .Iaddend.
.Iadd.15. A surface mounted LED package as recited in claim 14
wherein said slot is located at the center of the edges of said
second and third surfaces joining said first surface. .Iaddend.
.Iadd.16. A surface mounted LED package as recited in claim 11
wherein said first passageway guides and reflects light from said
LED to a light collecting surface of said lens. .Iaddend. .Iadd.17.
A surface mounted LED package as recited in claim 16 wherein said
second passageway has a cross-section sized and shaped to
accept said lens. .Iaddend. .Iadd.18. A surface mounted LED package
as recited in claim 11 wherein said second passageway has a
cross-section sized and shaped to accept said lens. .Iaddend.
.Iadd.19. A surface mounted LED package as recited in claim 11
wherein said two electrical contacts are located on said first
surface of said LED. .Iaddend. .Iadd.20. A surface mounted LED
package as recited in claim 11 wherein said housing is generally
rectangular parallelepipedal in shape. .Iaddend. .Iadd.21. A
surface mounted LED package as recited in claim 11 wherein said
second passageway extends from said second surface of said housing
to a third surface of said housing. .Iaddend. .Iadd.22. A surface
mounted LED package as recited in claim 11 wherein said radiating
surface of said lens is located outside said housing. .Iaddend.
.Iadd.23. A surface mounted LED package as recited in claim 11
wherein said internal reflecting surface of said lens is located
above said light emitting portion of said LED. .Iaddend. .Iadd.24.
A surface mounted LED package comprising:
(a) an LED having:
(i) two electrical contacts and
(ii) a light emitting portion and
(b) a housing mounted on said LED, said housing having:
(i) a first surface;
(ii) a second surface that is not parallel to said first surface;
and
(iii) a passageway extending through said housing from a first end
at said first surface to a second end at said second surface, said
passageway being sized, shaped, and positioned to receive said
light emitting portion of said LED into said first end of said
passageway and having a first internal reflecting surface that
reflects light from said light emitting portion of said LED out
through said second end of said passageway.
.Iaddend. .Iadd.25. A surface mounted LED package as recited in
claim 24 wherein said passageway comprises:
(a) a first passageway segment extending from said first end of
said passageway part way through said housing and
(b) a second passageway segment extending from said second end of
said passageway at least part way through said housing and
communicating with said first passageway segment. .Iaddend.
.Iadd.26. A surface mounted LED package as recited in claim 25
wherein said first and second passageway segments are straight.
.Iaddend. .Iadd.27. A surface mounted LED package as recited in
claim 25 wherein said second passageway segment extends all the way
through said housing. .Iaddend. .Iadd.28. A surface mounted LED
package as recited in claim 25 wherein said first internal
reflecting surface is located at the intersection of said first and
second passageway segments. .Iaddend. .Iadd.29. A surface mounted
LED package as recited in claim 24 and further comprising a lens
received in said passageway in position to receive light from said
light emitting portion of said LED, said lens having a radiating
surface sized, shaped, and positioned to radiate light from said
light emitting portion of said LED externally of said housing.
.Iaddend. .Iadd.30. A surface mounted LED package as recited in
claim 29 wherein said lens has a second internal reflecting surface
located in said housing in position to reflect light from said
light emitting portion of said LED toward said radiating surface of
said lens. .Iaddend. .Iadd.31. A surface mounted LED package as
recited in claim 29 wherein said radiating surface of said lens is
located outside said housing. .Iaddend. .Iadd.32. A surface mounted
LED package as recited in claim 29 wherein said radiating surface
of said lens protrudes outwardly from said housing. .Iaddend.
Description
FIELD OF THE INVENTION
This invention relates generally to structures for mounting visual
indicators on printed circuit boards. It relates particularly to
structures for mounting light-emitting diodes ("LEDs") on printed
circuit boards using surface mount technology.
CROSS-REFERENCE TO RELATED APPLICATION
This application is related to commonly assigned application Ser.
No. 07454,468, filed Dec. 21, 1989 concurrently herewith.
BACKGROUND OF THE INVENTION
Printed circuit boards using surface mount technology have several
advantages over prior printed circuit boards. In surface mount
circuit boards, through holes for mounting devices to the board are
completely eliminated. Instead, circuitry is packed close together,
and the space usually required for through holes is utilized more
efficiently. Accordingly, the boards can be smaller though carrying
the same amount of circuitry, or more circuitry can be carried by
the same sized board. Furthermore, the components mounted on the
circuit boards can be smaller than those used on conventional
printed circuit boards.
However, surface mount technology creates certain problems. Since
the printed conductors and components must be located closer
together than with other printed circuit boards, greater accuracy
in the location of components and conductors on the boards is
required. Furthermore, since wave soldering usually is not used,
radiant heating in an oven or the like usually is used to heat the
components and their leads so as to cause the preapplied solder
paste to melt and attach the components to the board. The more
demanding requirements of surface mount technology place greater
demands on the structures and techniques for mounting components,
visual indicators, etc. on the circuit boards.
Often it is necessary to mount visual indicators such as LEDs on a
printed circuit board with the light elevated above the surface of
the board and/or with the LED near to one edge of the board. Each
of these requirements creates special problems in the mounting of
the LEDs.
The mounting of circuit components on surface mount boards often is
accomplished simply by cutting the electrical lead conductors of
the devices bending the conductors to a proper shape, and then
soldering them to the pads on to which the devices are to be
mounted. This technique also has been used to mount LEDs on surface
mount boards. However, the leads usually provided for LEDs tend to
be too pliable and narrow to balance the LED on the circuit board
until it is soldered. Furthermore, the conical dome shape of LEDs
makes them incompatible with surface mount pick-and-place
mechanisms.
Perhaps the greatest deficiency of the above mounting technique
lies in the fact that conventional LEDs are not capable of
withstanding the heat associated with solder reflow processes.
Through-hole LEDs are constructed by embedding a lead frame in a
castable epoxy. Such encapsulants are not structurally sound at
solder reflow temperatures. The glass transition temperature for
casting epoxies is far lower than the temperature of the soldering
furnace. As the epoxy softens, the lead frame is allowed to move,
causing the ultimate breakage of the wire bond. Manufacturers that
have attempted to use conventional LEDs in surface mount processes
have experienced unacceptable failure rates.
Conversely, LEDs designed for surface mounting are well suited for
pick-and-place mechanisms, and they can successfully withstand
solder temperatures. However, lacking a focusing lens, these
miniature devices offer poor optical performance; low light
intensity levels, light bleeding when several LEDs are mounted in
close proximity, and the unavailability of right-angle viewable
devices.
OBJECTS OF THE INVENTION
Accordingly, it is an object of the present invention to provide a
structure for mounting visual indicators, particularly LEDs, on
printed circuit boards, particularly surface mount boards, with
strength, accuracy, and variability in positioning while providing
optical enhancements.
It is a further object of the invention to provide optical
enhancements that increase light intensity, focus light to reduce
light bleeding, and permit right-angle viewing.
It is still further object of the invention to provide such a
structure in which a visual indicator can be mounted a substantial
distance above the surface of the board and/or near one edge of the
board so that it can be seen more easily and whenever required for
any other reason.
It is a further object of the invention to provide such a structure
with relatively broad conductive support surfaces for attachment to
conductive pads on the boards with a high degree of accuracy and
precision and with mechanical strength.
It is a still further object of the invention to provide such a
structure which is well adapted for precise positioning on surface
mount boards by use of automated positioning equipment.
It is another object of the invention to provide such a structure
which is relatively compact and inexpensive to manufacture.
It is still a further object of the invention to provide such a
structure which overcomes or ameliorates the drawbacks of the prior
art discussed above.
SUMMARY OF THE INVENTION
With the foregoing in mind, a surface mounted LED package according
to the invention comprises an LED having a first surface, a second
surface opposite to the first surface, two electrical contacts on
the first surface, and a light emitting portion in the second
surface; a housing mounted on the LED and having a generally
rectangular parallelepipedal shape, a first passageway extending
from a first surface of the housing part way through the housing,
the first passageway being sized, shaped, and positioned to receive
the second surface of the LED such that the light emitting portion
of the second surface faces into the first passageway, and a second
passageway extending from a second surface of the housing to a
third surface of the housing and communicating with the first
passageway; and a lens received in the second passageway and having
a first radiating surface located outside the housing and an
internal reflecting surface located inside the housing above the
light emitting portion of the LED in position to reflect light from
the light emitting portion of the LED toward the radiating
surface.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of a surface mounted LED
package according to the invention.
FIG. 2 is a front view of the surface mounted LED package shown in
FIG. 1.
FIG. 3 is a cross sectional view on the line III--III in FIG.
2.
FIG. 4 is a perspective view of an array of three surface mounted
LED packages of the type shown in FIG. 1 mounted on the edge of a
printed circuit board.
FIG. 5 is a perspective view of a single housing containing a
plurality of LEDs.
DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENT
A surface mounted LED package 10 is shown in FIGS. 1-3. It
comprises an LED 12, a housing 14, and a lens 16.
The LED 12 may be of any conventional kind--for instance, the kind
sold under the designation BR1102W by Stanley. All that is
important for present purposes is that it has a first surface 18, a
second surface 20 opposite to the first surface 18, two electrical
contacts 22 on the first surface 18, and a light emitting portion
24 in the second surface 20.
The housing 14 is mounted on the LED 12 by any appropriate means,
such as by press fitting, by ultrasonic welding, or by gluing. The
housing 14 has a generally rectangular parallelepipedal shape,
thereby being well adapted for precise positioning on a circuit
board by the use of automated positioning equipment. A first
passageway 26 extends from a first surface 28 of the housing 14
part way through the housing 14. As best seen in FIG. 3, the first
passageway 26 is sized, shaped, and positioned to receive the
second surface 20 of the LED 12 such that the light emitting
portion 24 of the second surface 20 faces into the first passageway
26. A second passageway 30 extends from a second surface 32 of the
housing 14 to a third surface 34 of the housing 14 and communicates
with the first passageway 26.
As best seen in FIG. 3, the lens 16 is received in the second
passageway 30. It has a radiating surface 36 located outside the
housing 14, a light collecting surface located 38 above the light
emitting portion 24 of the LED 12, and an internal reflecting
surface 40 located inside the housing 14 in position to reflect
light from the light collecting surface 38 toward the radiating
surface 36.
The light collecting surface 38 can be flat, concave to maximize
light entry, or convex to focus light in conjunction with the
internal reflecting surface 40 and the radiating surface 36. Other
variations of the light collecting surface 38 and the internal
reflecting surface 40 (such as stepped reflectors, fresnel
surfaces, conic sections, or polynomial surfaces) are possible.
Additionally, the lens 16 is not limited to a generally round shape
with a dome-shaped radiating surface 36. Lens barrel shapes
following square, rectangular, or other polygons can be
accommodated. Similarly, the radiating surface 36 can be designed
as flat, fresnel, jewelled, or in other configurations depending on
specific needs.
The lens 16 can be press fit or glued into the second passageway
30. Alternatively, and as illustrated in FIG. 3, the lens 16 can be
held in place by a flange 42 sandwiched between a wall 44 of the
first passageway 26 and a stepped surface 46 of the LED 12. Lens
retention can also be accomplished by a mass of plastic material 48
filling the portion of the second passageway 30 not filled by the
lens 16. Preferably the mass of plastic material 48 is composed of
an opaque reflecting material that supplements the function of the
internal reflecting surface 40.
As best seen in FIG. 3, the first passageway 26 and the second
passageway 30 are preferably perpendicular to each other and the
internal reflecting surface 40 is preferably disposed at 45.degree.
to both the first passageway 26 and the second passageway 30.
As best seen in FIG. 1, the housing 14 preferably has a slot 50 in
its second (or front) surface 32 extending from its second surface
32 to its third (or rear) surface 34. As best seen in FIG. 2, the
first passageway 26 preferably communicates with the slot 50, and
the slot 50 is preferably located at the center of the sides of the
second surface 32 and the rear surface 34 joining the first surface
28.
FIG. 4 illustrates an array of three surface mounted LED packages
10 according to the invention mounted on a printed circuit board 44
near one of its edges.
FIG. 5 illustrates a single housing 54 containing a multiplicity of
LEDs 12 and supplemental optics. A package containing multiple LEDs
collecting into a single radiating surface is also possible.
Obviously, numerous modifications and variations of the present
invention are possible in light of the above teachings. It is
therefore to be understood that, within the scope of the appended
claims, the invention may be practiced otherwise than as
specifically described herein.
* * * * *