U.S. patent application number 14/209883 was filed with the patent office on 2014-07-17 for multicolor light emitting diodes.
This patent application is currently assigned to Apple Inc.. The applicant listed for this patent is Apple Inc.. Invention is credited to Brett Bilbrey, Michael F. Culbert, Duncan Kerr, Aleksandar Pance.
Application Number | 20140197432 14/209883 |
Document ID | / |
Family ID | 42541510 |
Filed Date | 2014-07-17 |
United States Patent
Application |
20140197432 |
Kind Code |
A1 |
Pance; Aleksandar ; et
al. |
July 17, 2014 |
MULTICOLOR LIGHT EMITTING DIODES
Abstract
A device such as a multicolor light emitting diode that emits
different colors of light and that may combine the different colors
emitted by individual light emitting diodes. The multicolor LED may
include a common anode terminal that may be connected to each anode
of the individual light emitting diodes. The multicolor LED may be
a five terminal multicolor LED. Additionally, the multicolor LED
may include two anode terminals, in which the first anode terminal
may be a common anode terminal connected to three of the individual
color LEDs and the second anode terminal may be connected to an
anode of a white LED. In this embodiment, the multicolor LED may be
a six terminal multicolor LED.
Inventors: |
Pance; Aleksandar;
(Saratoga, CA) ; Kerr; Duncan; (San Francisco,
CA) ; Bilbrey; Brett; (Sunnyvale, CA) ;
Culbert; Michael F.; (Monte Sereno, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Apple Inc. |
Cupertino |
CA |
US |
|
|
Assignee: |
Apple Inc.
Cupertino
CA
|
Family ID: |
42541510 |
Appl. No.: |
14/209883 |
Filed: |
March 13, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13715864 |
Dec 14, 2012 |
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14209883 |
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|
12495353 |
Jun 30, 2009 |
8339028 |
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13715864 |
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Current U.S.
Class: |
257/89 |
Current CPC
Class: |
H01L 2924/0002 20130101;
H01L 33/58 20130101; G02B 6/0068 20130101; H01L 33/62 20130101;
H01L 25/0753 20130101; H01L 33/08 20130101; H01L 2924/00 20130101;
H01L 2924/0002 20130101 |
Class at
Publication: |
257/89 |
International
Class: |
H01L 33/08 20060101
H01L033/08 |
Claims
1. A light emitting package; comprising: a rectangular light guide
with one or more angled corners, wherein each angled corner extends
approximately 135 degrees from adjacent sidewalls of the light
guide; and a light emitting diode (LED) positioned adjacent to one
of the angled corners, wherein because the angled corner extends
approximately 135 degrees from adjacent sidewalls of the light
guide, light emitted from the LED is more evenly dispersed within
the light guide than if the LED were positioned adjacent to a
sidewall
2. The light emitting package of claim 1, further comprising a
first set of one or more LEDs, wherein each LED in the first set of
LEDs: is positioned adjacent to one of the angled corners; and
emits a white light or a colored light.
3. The light emitting package of claim 2, further comprising second
set of one or more LEDs, wherein each LED in the second set of LEDs
is positioned adjacent to a sidewall of the light guide; and emits
a white light or a colored light.
4. A light emitting package comprising: a multicolor LED operative
to emit a colored light; and a first rectangular light guide
optically coupled to the multicolor LED, wherein the first
rectangular light guide comprises a first rectangular prism portion
and a first ramp-shaped portion that is adjacent and contiguous
with the first rectangular prism portion, and wherein the first
ramp-shaped portion is configured to direct light exiting the
multicolor LED either upward or downward into the first rectangular
prism portion.
5. The light emitting package of claim 4, further comprising: a
white LED operative to emit a white light; and a second rectangular
light guide optically coupled to the white LED, wherein: the second
rectangular light guide is adjacent the first rectangular light
guide; and the second rectangular light guide comprises a second
rectangular prism portion and a second ramp-shaped portion that is
adjacent and contiguous with the second rectangular prism portion,
wherein the second ramp-shaped portion is configured to direct
light exiting the white LED either upward or downward into the
second rectangular prism portion.
Description
RELATED APPLICATIONS
[0001] This application is a divisional of, and hereby claims
priority under 35 U.S.C. .sctn.120 to, pending U.S. patent
application Ser. No. 13/715,864, titled "Multicolor Light Emitting
Diodes" by Aleksandar Pance, Duncan Kerr, Brett Bilbrey, and
Michael F. Culbert, which was filed on 14 Dec. 2012 (Atty. Docket
No.: APL-P7612USD1), and which is incorporated by reference. U.S.
patent Ser. No. 13/715,864 is itself a divisional of U.S. patent
application Ser. No. 12/495,353, titled "Multicolor Light Emitting
Diodes" by Aleksandar Pance, Duncan Kerr, Brett Bilbrey, and
Michael F. Culbert, which was filed on 30 Jun. 2009 (Atty. Docket
No.: APL-P7612US1), which issued as U.S. Pat. No. 8,339,028 on 25
Dec. 2012, to which parent application Ser. No. 13/715,864 claims
priority, and which is incorporated by reference.
[0002] This application is related to U.S. patent application Ser.
No. 12/495,230, titled "Multicolor Lighting System," by Aleksandar
Pance, Duncan Kerr, Brett Bilbrey, and Michael F. Culbert, which
was filed on Jun. 30, 2009 (Atty. Docket No.: APL-P7613US1), which
issued at U.S. Pat. No. 8,138,687 on 20 Mar. 2012, and which is
incorporated by reference.
BACKGROUND
[0003] 1. Technical Field
[0004] The present invention generally relates to light emitting
diodes and, more specifically, to multicolor light emitting
diodes.
[0005] 2. Background Discussion
[0006] Many electronic components, devices and/or systems employ
some type of light source which may be used for various purposes
such as providing light for better visibility, decoration,
indicators, imaging and so on. Depending on the use, the type of
light source may be fluorescent, halogen, incandescent, mercury
vapor, high pressure or low pressure sodium, light emitting diodes
("LEDs") and so on.
[0007] In particular, LEDs may be used in a number of applications
and may provide light more efficiently. They may also yield
increased performance lifetimes over other light sources such as,
incandescent lights. Additionally, LEDs may have other advantages
such as smaller packaging sizes, increased power efficiency and so
on. LEDs may also produce and/or transmit less thermal energy, thus
keeping the casing and/or packaging surrounding the LEDs cooler
than other light sources.
[0008] Although LEDs may more efficiently produce light than many
of the previously mentioned traditional light sources, the
intensity of the light emitted by LEDs may not be sufficient for
some purposes and/or a greater intensity of light may be desirable.
For example, a greater light intensity may be desirable for
employing LEDs as indicators, light sources for visibility,
backlighting, imaging and so on. Additionally, the LED light
intensity may depend on the LED color. In one example, red light
may have a greater intensity than blue light at the same power, but
it may be desirable to display the colors at similar intensities.
Accordingly, there is a need in the art for an improved device that
includes the ability to provide multiple colors at a range of
intensities.
SUMMARY
[0009] Generally, one embodiment of the present invention may take
the form of a multicolor light emitting diode. The multicolor light
emitting diode may include a first light emitting diode that emits
white light, a second light emitting diode that emits red light, a
third light emitting diode that emits green light, a fourth light
emitting diode that emits blue light and a housing surrounding at
least the first light emitting diode, the second light emitting
diode, the third light emitting diode and the fourth light emitting
diode. The multicolor light emitting diode may also include a
window defined in the housing, such that each of the first, second,
third, and fourth light emitting diodes may emit light through the
window. Additionally, the multicolor light emitting diode may
include four cathode terminals and a common anode terminal, such
that the cathode and the anode may be connected to the housing.
Each one of the four cathode terminals may be operationally
connected on a one to one basis to each of the cathodes of the
first, second, third and fourth light emitting diodes and the
common anode terminal may be operationally connected to all of the
anodes of first, second, third and fourth light emitting
diodes.
[0010] Another embodiment may take the form of a method for
providing colors of light. In this method a first light emitting
diode that emits white light may be provided, as well as a second
light emitting diode that emits red light, a third light emitting
diode that emits green light, a fourth light emitting diode that
emits blue light. Additionally, at least the first light emitting
diode, the second light emitting diode, the third light emitting
diode and the fourth light emitting diode may be surrounded by a
housing. Separate windows may be defined in the housing for each of
the first, second, third, and fourth light emitting diodes so that
the light emitted by each may pass through the separate windows.
Additionally, four cathode terminals and a common anode terminal
may be connected to the housing and each one of the four cathode
terminals may be operationally connected on a one to one basis to
each of the cathodes of the first, second, third and fourth light
emitting diodes, and the common anode terminal may be operationally
connected to all of the anodes of first, second, third and fourth
light emitting diodes.
[0011] These and other advantages and features of the present
invention will become apparent to those of ordinary skill in the
art upon reading this disclosure in its entirety.
BRIEF DESCRIPTION OF THE FIGURES
[0012] FIG. 1 depicts an embodiment of a multicolor LED
schematic.
[0013] FIG. 2 depicts an embodiment of the present invention as a
top firing five terminal multicolor LED package.
[0014] FIG. 3 depicts another embodiment of the present invention
as a side firing five terminal multicolor LED package.
[0015] FIG. 4 depicts another embodiment of a multicolor LED
schematic.
[0016] FIG. 5 depicts another embodiment of the present invention
as a top firing six terminal multicolor LED package.
[0017] FIG. 6 depicts another embodiment of the present invention
as a side firing six terminal multi color LED package.
[0018] FIG. 7 depicts yet another embodiment of the present
invention in another LED multicolor package.
[0019] FIG. 8 depicts a top-down view of an alternative multicolor
LED package.
[0020] FIG. 9 depicts a cross-sectional view of the LED package of
FIG. 8, showing one sample cross-section taken along line A-A of
FIG. 8.
[0021] FIG. 10 depicts an alternate cross-sectional view of the LED
package of FIG. 8, showing a second sample cross-section taken
along line A-A of FIG. 8.
[0022] FIG. 11 depicts a top-down view of yet another multicolor
LED package.
DETAILED DESCRIPTION
[0023] Generally, one embodiment may take the form of an electronic
device, such as an LED, which may be capable of emitting various
colors individually or in combination. In this embodiment, the LED
may be a multicolor LED, which may include and incorporate multiple
individual LEDs that may emit different colors of light from one
another. For example, the multicolor LED may include individual
LEDs, each emitting one of red, green, blue and white light.
Generally, an LED that emits red light may be referred to herein as
a "red LED," an LED that emits green light may be referred to
herein as a "green LED," and so on. Continuing this example, the
multicolor LED may emit white light in various ways, such as by
combining the emitted colors of the red LED, the green LED and the
blue LED, by using the white LED alone, and/or any combination
thereof.
[0024] Continuing the description of the embodiment, the multicolor
LED may be packaged in a number of ways. In one example, light may
be emitted from the top of the package. In another example, light
may emanate from the side of the package. In other embodiments the
light may be emitted from any package surface depending on the
configuration of the LED package. For example, the multicolor LED
may be a top-firing multicolor LED and the multicolor LED packaging
may allow light to be emitted from a transparent window defined in
the top of the package.
[0025] Continuing the embodiment, the multicolor LED may be
configured so that two or more of the individual LEDs may share a
common anode, each LED may have an individual anode, or all of the
individual LEDs of the multicolor LED may share a common anode. For
example, the red LED, the green LED and the blue LED may share a
common anode and the white LED may have a separate anode, all four
of the LEDs may share a common anode and so on.
[0026] Another embodiment may take the form of a method for
producing various colors, including white light, from a single
device such as a multicolor LED. The multicolor LED may include
individual LEDs, each of which may emit different colors from one
another (or some of the individual LEDs may emit different colors
than others). By combining the different colors emitted by the
individual LEDs, the resulting emitted color may be a different
color, or may be a different intensity color. For example, the
multicolor LED may emit a white light by combining red, green and
blue colors emitted respectively by a red LED, a green LED and a
blue LED and may increase the intensity of the white light by
additionally combining white light emitted by a white LED.
Additionally, white light may be produced at a better power
efficiency by combining the emitted light from the red, green, blue
and white LEDs, then by producing white light by combining only the
emitted light from the red, green and blue LEDs without the white
light from the white LED.
[0027] It should be noted that embodiments described herein may be
used in a variety of image processing and/or lighting systems. The
embodiment may include or work with a variety of display
components, monitors, screens, images, sensors, indicators and
electrical devices. Aspects of the present invention may be used
with practically any apparatus related to optical and electrical
devices, display systems, presentation systems or any apparatus
that may contain any type of display and/or lighting system.
Accordingly, embodiments of the present invention may be employed
in computing systems and devices used in visual presentations and
peripherals and so on.
[0028] Before explaining the disclosed embodiments in detail, it
should be understood that the embodiments are not limited in their
application to the details of the particular arrangements shown,
because other embodiments are possible. Also, the terminology used
herein is given for description and not limitation.
[0029] FIG. 1 depicts a schematic of a sample electronic device
100. The electronic device 100 may be a multicolor LED 100
configured to emit one or more colors of light. Typically,
multicolor LEDs include more than one individual LED, each of which
may emit a certain wavelength of light corresponding to a color
range. Generally, a single LED emits wavelengths of a single color,
such as red. By varying either the duty cycle of or voltage to the
LED, the intensity of the emitted light may be varied. For some
LEDs, changes in input voltage may yield changes in the outputted
light's wavelength. Each individual LED of the multicolor LED may
emit the same color or may emit different colors. For example, a
multicolor LED may have four LEDs and all of the four LEDs may emit
red light, or two of the four LEDs may emit red light, one LED may
emit green light and the remaining LED may emit blue light, or each
of the LEDs may emit a different color light from all others.
Additionally, multicolor LEDs may include various numbers of
individual LEDs as appropriate. In another example and as shown in
FIG. 1, the multicolor LED 100 may be housed in a single package
and may include four individual LEDs, specifically a white LED 130,
a red LED 132, a green LED 134 and a blue LED 136.
[0030] FIG. 1, depicts a multicolor LED that produces different
colors from each of the individual LEDs. Although LED 100 includes
only four LEDs, the multicolor LED 100 may contain any number of
individual LEDs greater than one LED, in which the individual LEDs
may produce the same or different colors as one another.
Additionally, although the LEDs 130, 132, 134 and 136 are depicted
as configured in a specific order left to right in FIG. 1, and with
specific colors, the individual LEDs of a multicolor LED may
configured in various arrangements, may include fewer LEDs or a
greater number of LEDs, and may emit various colors.
[0031] Generally, LEDs may emit light in wavelengths across the
visible, ultraviolet and infrared spectrum. In the example of FIG.
1, the multicolor LED 100 may emit colors other than those
generated by a single LED by combining two or more colors to
produce a color other than red, green, blue or white. Combining
colors to produce a different color may be referred to as "additive
color mixing." For example, the LED may emit a magenta color by
combining red and blue light. In another example, the LED may emit
white light by combining equal intensities of red, green and blue
light. Combining different colors of light with white light will be
discussed in more detail below. Although a specific color may be
referred to herein, it should be understood that such a color may
any of a range of wavelengths. For example, the color produced by
an LED emitting light between the wavelengths 610 nanometers (nm)
and 760 nm may appear, and be referred to as "red."
[0032] LED colors may be combined to produce different colors, but
may also be combined to change the saturation of the color and/or
to provide a greater intensity. As used herein, saturation
generally refers to the amount of white light in the resulting
color. For example, white light and red light may be combined to
produce a resulting color and may be referred to as a pastel red (a
less saturated red). Each of these effects will be discussed in
further detail below.
[0033] The resulting color may be distinct from the color emitted
by either of the two light sources or may appear as a similar color
to one of the two light sources. For example, a light emitted by a
red LED and a blue LED may be combined to produce a yellow color,
in which the yellow color may be at a greater intensity than either
one of the colors emitted by the red LED or the blue LED when
viewed individually. In another example, the light emitted by a red
LED and a white LED may be combined to emit a reddish color, which
may be at a greater intensity than light emitted by either one of
the red LED or the white LED when viewed individually. The combined
emitted light may be a more pastel red color (less saturated red),
than the red light emitted by the red LED when viewed individually.
Generally, adding together the light emitted from two or more light
sources, both at a defined power, may result in an outputted light
having increased intensity as well as a different tint or
saturation when compared to either one of the two constituent light
sources individually.
[0034] By varying the light intensities of the light emitted by
each of the individual LEDs, the combinations of colors may also be
varied. Generally, an LED may emit a color at different
intensities. For example, although the red light emitted by the red
LED 132 may also be combined with the white light emitted by the
white LED 130 to produce a pastel (although intense) color red, the
two emitted colors may have different intensities. Continuing this
example, the red light emitted by the red LED 132 may be at a
minimum intensity and the white light emitted by the white LED 130
may be at a maximum intensity, thus producing a pale pink-white
light. Alternatively, the red light emitted by the red LED 132 may
be at a maximum intensity and the white light emitted by the white
LED 130 may be at a minimum intensity and produce a less saturated
red color that may appear as a slightly faded reddish color. The
color combinations produced by varying the light intensities of the
light emitted by the individual LEDs may or may not fall within
either one of the frequency ranges of the light emitted by the
individual LEDs.
[0035] In the embodiment of FIG. 1, white light may be produced in
various ways such as by combining the three emitted colors of red
LED 132, green LED 134 and blue LED 136, or by emitting white light
from the white LED 130 or by combining various other colors in
combination as appropriate to produce white light. Stated
differently, combining any number of colors in the appropriate
combinations may also produce white light. For example, the magenta
light emitted by a magenta LED in combination with the green light
emitted by a green LED may produce white light.
[0036] Additionally, as previously discussed, a multicolor LED may
emit white light with increased intensity by combining the light
emitted by the combination of the three LEDs (red LED 132, green
LED 134, blue LED 136) and the white LED 130. The white LED 130 may
be used in combination with the three LEDs 132, 134, 136 of FIG. 1
in order to increase the intensity of the white light produced by
the three LEDs, or may be used to increase the power efficiency of
LED 100. For example, assuming the same intensity, the white LED
130 may produce a white light more efficiently in comparison to
producing a white light using the three LEDs in combination to
produce white light. Generally, power efficiency of an LED, as
discussed herein, may refer to the light output per unit power
input.
[0037] Generally an LED may have a cathode and an anode. As used
herein, the phrases regarding the LED being forward biased,
switched "on" or with a closed switch, all refer to the same LED
state and all indicate that the individual LEDs may emit light when
in the aforementioned state.
[0038] Still with respect to FIG. 1, the white LED 130, red LED
132, green LED 134 and blue LED 136 may be operationally or
directly connected and in parallel with one another. The multicolor
LED 100 may include a common anode 120 and separate cathodes 110,
112, 114, 116. The anodes and cathodes of LEDs 130, 132, 134 and
136 may be operationally or directly connected to the respective
package terminals and the connections will be described in further
detail below. Generally, common anodes may provide increased
flexibility of use. For example, a multicolor LED with a common
anode may include multiple terminals connected to the common anode,
thus providing a greater number of ways to connect to the common
anode of the multicolor LED.
[0039] In FIG. 1, the white LED 130 is connected to the common
anode 120. Similarly, the red LED 132, green LED 134 and blue LED
136 are also connected to the common anode 120. Further, the white
LED 130 may be connected to a first cathode 110, the red LED 132
may be connected to a second, separate cathode 112, the green LED
134 may be connected to a third, separate cathode 114 and the blue
LED 136 may be connected to a fourth, separate cathode 116.
Generally, the common anode may be connected to two or more of the
LED anodes, which will be discussed in further detail below with
respect to FIGS. 4-6.
[0040] FIG. 2 depicts a top view of one example embodiment of a top
firing five terminal LED package 200. The embodiment shown in FIG.
2 has the same LED connections shown in FIG. 1. The LED package 200
may emit light from the top of the package and may house a
multicolor LED like that shown in FIG. 1. Although the examples
discussed herein with respect to FIGS. 1 and 2 use the colors
white, red, green and blue, any color LED may be used.
[0041] As shown in FIG. 2, the LED package 200 may include one
window through which the colors emitted by the multicolor LED may
pass. Alternative embodiments may have multiple windows. For
example, the LED package may include four windows, in which each
window emits the light emitted by one of the individual LEDs. In
another example, the LED package may include two windows, in which
the light emitted by the white LED may pass through a first window
and the light emitted by the red, green and/or blue LED may pass
through a second window.
[0042] The light emitted from the individual LEDs may be coupled
using a light guide (not shown) located within, adjacent to, or
formed as part of the LED package 200. Depending on the
configuration of the individual LEDs (discussed below), one or more
light guides may be used inside the LED package to couple the light
from the LED through the LED package window. As discussed herein,
the term LED may also include LED die. For example, one light guide
may couple the light from the four LEDs such that the light emitted
from anyone of the four LEDs may be emitted from the window of the
LED package. Alternatively, the LED package may have two windows,
thus, two light guides may be used. A first light guide may couple
light from the white LED through the first window and the second
light guide may couple light from any of the red, green and/or blue
LEDs through the second window.
[0043] Additionally, the physical arrangement of the individual
LEDs within the package as shown in FIG. 2, may be arranged in a
two by two grid, may be arranged in a horizontal linear pattern, a
vertical linear pattern or any grid or pattern including randomly.
The configuration of the LEDs within the package may depend on the
intended use of the package, the size of the LEDs, the desired
uniformity of the color to be emitted from the package and so on.
For example, the white LED may be centrally located and the red,
green and blue LEDs may be arranged around the white LED to
increase the color uniformity and intensity uniformity of the
emitted light from the multicolor LED.
[0044] The LED package 200 in FIG. 2 has six physical terminals,
including five functionally different terminals, and thus the LED
package 200 may be referred to herein as a "five terminal LED"
package. Two of the terminals, namely a first anode terminal 220
and a second anode terminal 222 may be operationally or directly
connected to the common anode of the multicolor LED. Although the
LED package 200 includes two anode terminals, the first anode
terminal 220 and the second anode terminal 222, both of the anode
terminals may functionally serve the same purpose. Stated
differently, the first and second anode terminals 220 and 222 of
FIG. 2 may both be operationally or directly connected to common
anode 120 of FIG. 1 and may be used interchangeably. Different
anode connections will be discussed in further detail below.
[0045] LED package 200 also may include four cathode terminals as
shown in FIG. 2. Cathode terminal 210 may be operationally or
directly connected to the cathode of white LED 110 of FIG. 1 and
cathode terminals 212,214 and 216 may be operationally or directly
connected to the cathodes of red LED 112, green LED 114 and blue
LED 116 of FIG. 1. Generally, terminals may be referred to as
operationally connected in various arrangements that allow the
terminal to operate in a similar manner as a direct connection. For
example, a terminal may be operationally connected even though an
additional electrical component such as a resistor may be inserted
in the connection between the terminal and the LED. Additionally,
the terminals may be located such that the LED package 200 may be
used interchangeably with other six terminal device packages. The
LED package may be sized such that a backlit keyboard may have one
LED package underlying and backlighting each individual key.
However, the size of the LED package 200 may depend on the intended
use of the LED package, on the size of the individual LED die and
so on.
[0046] FIG. 3 depicts a side view of another example embodiment of
a side firing five terminal LED package 300. The embodiment shown
in FIG. 3 has the same LED connections shown in FIG. 1. The LED
package 300 may emit light from the side of the package through a
transparent window and, similar to the LED package 200 of FIG. 2,
may enclose a multicolor LED. In FIG. 3, the multicolor LED package
300 may include individual LEDs 330, 332, 334 and 336 which may
emit white, red, green and blue light respectively. The individual
LEDs may be configured within the multicolor LED as described in
FIG. 1. Although the examples discussed herein use the colors
white, red, green and blue, any color LEDs may be used.
[0047] FIG. 3 has six physical terminals, including five
functionally different terminals. The first and second anode
terminals 320 and 322 may be operationally or directly connected to
the common anode of the multicolor LED. As previously discussed
with respect to FIG. 2, although the LED package 300 includes two
anode terminals 320 and 322, both of the anode terminals may
functionally serve the same purpose in that either one of the anode
terminals 320, 322 may be used interchangeably.
[0048] The side firing LED package 300 also may include four
cathode terminals. Cathode terminal 310 may be operationally or
directly connected to the cathode of white LED 310 of FIG. 3 and
cathode terminals 312,314 and 316 may be operationally or directly
connected to the cathodes of red LED 312, green LED 314 and blue
LED 316 of FIG. 3. Additionally, although the die and the LED
package terminals are depicted in a specific order, the die and the
package terminals may be arranged in any order. Also, the anode
terminals 320, 322 of FIG. 3 are shown adjacent to one another, but
may be located in any position on the LED package, including
alternating with the cathode terminals, at opposite ends of the LED
package and so on. Because the white LED 330 and the blue LED 336
are both connected to a common anode (shown in FIG. 1), either one
of the first or second anode terminals 320, 322 may be connected to
the power source so that the LEDs 330,336 may be switched on
(stated differently, both first and second anode terminals 320 and
322 need not be connected to the power source to turn on LEDs 330,
336).
[0049] Depending on the intended use of the LED package, either of
a top-firing or side-firing LED package 200 may be used. For
example, for backlighting a keyboard, the top-firing LED package
may be used as it allows light to be emitted from the top of the
package. Stated differently, in a backlit keyboard, the multicolor
LED may be located beneath the keyboard, thus making it useful to
employ a top firing LED package.
[0050] FIG. 4 depicts a schematic of another embodiment of an
electronic device 400. The electronic device 400 may be a
multicolor LED, which may emit one or multiple colors individually
or in any combination and may include individual LEDs, 430, 432,
434, 436. Similar to the embodiment shown in FIG. 1, the individual
LEDs 430, 432, 434, 436, may emit the colors white, red, green and
blue respectively. The schematic of FIG. 4 includes two anodes, 420
and 422, in which anode 422 is a common anode for the red LED 432,
green LED 434 and blue LED 436. In the six terminal multicolor LED,
the anode 422 may be connected to any three of the individual LED
anodes. In one example, the anode 422 may be connected to the
anodes of the white LED 430, the red LED 432 and the green LED
434.
[0051] The six terminal multicolor LED discussed with respect to
FIG. 4 is included within the LED package depicted in FIG. 5.
Accordingly, the embodiment shown in FIG. 5 has the same LED
connections shown in FIG. 4. FIG. 5 provides a top view
illustration of a top firing six terminal LED package 500. Similar
to the LED packages illustrated in FIG. 3, the top firing LED
package 500 may emit light from its top and has six physical
terminals. The LED package 500 includes a first anode 520 and a
second anode 522, which may be connected to different individual
LED anodes and are not interchangeable with one another since the
functionality of the first and second anodes is different with
respect to one another. In the embodiment of FIG. 5, depending on
the emitted colors of light desired, either first anode 520 or
second anode 522 may be connected to the power source, and thus
connect the respective LED. For example, the first anode 520 may be
connected to the power source and a white light may be emitted from
white LED 530. FIG. 5 also includes cathodes 510,512,514,516, which
may be operationally and/or directly connected to the cathodes of
white LED 530, red LED 532, green LED 534 and blue LED 536.
[0052] In one example of the embodiment shown in FIG. 5, the LED
package may emit a red light and a white light. In this example,
both of the anodes 520, 522 may be connected to the power source so
that the LEDs 530,536 may be switched on. Distinct from the
embodiment shown in FIG. 3 and as previously mentioned, anode 520
may be connected to the anode terminal of white LED 530 and anode
522 may be connected to the anodes of red, green and blue LEDs.
Additionally, the cathodes 510,516 may be connected to the power
source so that the LEDs 330, 336 may be switched on and emit white
and blue light respectively.
[0053] In another example of FIG. 5, the LED package 500 may emit a
yellow color. In this example, the anode 522 and the cathodes of
green LED 534 and blue LED 536 may be connected to the power source
so that the individual blue and green LEDs may emit light.
Continuing this example, the white LED 530 may not emit light as
the anode 520 need not be connected to the power source. Because
the anode of the white LED 530 may not be connected to a power
source, white LED 530 may have the ability to be switched on even
if a bias is applied to the cathode.
[0054] FIG. 6 depicts yet another embodiment of an LED package 600,
which may be a six terminal side firing LED package 600. The
embodiment shown in FIG. 6 has the same LED connections shown in
FIG. 4. As previously discussed with respect to FIG. 3, side-firing
LED package 600 may emit light from the side of the package, may
include four individual LEDs, (e.g., white, red, green and blue)
and may include a window which may allow the light emitted from the
individual LEDs to pass through. LED package 600 may include anodes
620, 622 which may be similarly connected as the anodes 420, 422 of
LED 400. Anode 620 may be connected to the anode of the white LED
630 and anode 622 may be connected to a common anode which, in
turn, may be connected to the anodes of red LED 632, green LED 634
and blue LED 636. Also similar to the LED package 500 of FIG. 5,
anodes 620 and 622 may both be connected to a power source, thus
allowing anyone of the LEDs to be switched on and emit light.
[0055] Although five and six terminal packages have been discussed
herein as examples, a package may include any number of terminals.
For example, an LED package may include a multicolor LED that may
emit four colors. The multicolor LED may be electrically configured
similar to the schematic of FIG. 4, in which the multicolor LED may
include four individual LEDs and also may include two anodes one of
which is a common anode for three of the LED (red, green and blue
LEDs) anodes, and the second anode which may be connected to an
individual white LED anode. The package may also include ten
terminals in which four of the terminals may be connected to the
cathodes of the individual LEDs, two of the terminals may be
connected to the white LED anode and the remaining three terminals
may be connected to the common anode for the three individual color
LEDs.
[0056] In another embodiment, a side-firing LED package may emit a
blue light and a white light, when the blue LED and the white LED
are active. In this embodiment, the side-firing LED package may
have four different color LEDs (for example, white, red, green,
blue), and each LED may have separate anode and separate cathodes.
Thus, it may be possible to produce different intensity light from
each individual LED, and more than one LED may emit light at the
same time. For example, the anodes of the blue and the white light
may be separately connected to separate power sources so that the
blue and white LEDs may be switched on and emit white and blue
light respectively and the intensity of the light produced by each
may be separately controlled.
[0057] FIG. 7 depicts yet another LED package 700. The LED package
700 may be configured to include various numbers of terminals, but
is illustrated in FIG. 7 with five terminals. The LED package 700
may function similarly to the LED packages described herein with
respect to FIGS. 1-6.
[0058] FIG. 8 depicts an implementation of a multicolor LED package
800 having two side-firing LEDs, namely one multicolor LED 810 and
one white LED 820. As shown in FIG. 8, the multicolor LED 810 and
white LED 820 are situated at opposing sides of the light guide
830. By positioning the LEDs in this fashion, each may have a
relatively large and uniform dispersal pattern for emitted light,
since neither LED is located closer to one adjacent side than the
other. A package 850 may surround the LEDs and light guide and is
shown in dashed lines. It should be noted that such a package is
optional with respect to this or other embodiments discussed
herein. Further, the package, LEDs, and/or light guide(s) generally
are situated or, or electrically connected to, a base such as a
printed circuit board 840.
[0059] FIG. 9 shows one sample cross- section for the LED package
800 of FIG. 8, generally taken along line A-A of FIG. 8. In
particular, FIG. 9 depicts the configuration of the light guides
930, 940 for the multicolor LED 910 and white LED 920. Each light
guide 930, 940 is generally ramp-shaped in a vertical cross section
and a rectangular prism in a lateral cross section (the length of
the rectangular prism varying with the point at which the
cross-section is taken, due to the angled edge of the ramp). The
first light guide 940 directs and/or diffuses light from the
multicolor LED 910 in a desired pattern in order to illuminate an
item above the waveguide while the second light guide 930 does the
same for the white LED 920. It should be noted that the second
light guide 930 may be configured to take into account the
scattering pattern of the first light guide 940. That is, since the
second light guide is located beneath the first light guide, the
two may cooperate to provide a desired final illumination pattern
for the white LED.
[0060] In alternative embodiments, the upper, first light guide may
be optically coupled to the white LED 920 and the second, lower
light guide 930 optically coupled to the multicolor LED 910 (for
example, the positions of the LEDs may be flipped).
[0061] FIG. 10 depicts an alternate construction of the LED package
800 of FIG. 8, particularly with respect to the configuration of
the light guides 1010, 1020. This cross-section may also be taken
along line A-A of FIG. 8 when the alternate construction is
employed. Here, instead of being ramp-shaped like the light guides
910, 920 of FIG. 9, each light guide 1010, 1020 is formed from a
ramp-shaped portion 1030, 1040 and a rectangular prism portion
1050, 1060. Each ramp-shaped portion is adjacent to and contiguous
with the associated rectangular prism portion. The ramp-shaped
portion directs light exiting the appropriate LED 810, 820 either
upward or downward into the rectangular prism, where the light is
emitted upward. Further, the shaded areas 1070, 1080 at the end of
each rectangular prism 1050, 1060 may be part of the light guide
and formed from the same material, in which case they are
contiguous with the adjacent rectangular prism, may be empty air or
may be formed from another material, such as an insulator, opaque
or reflective material.
[0062] Although FIGS. 8-10 depict the multicolor LEO and white LEO
on opposing sides of the LEO package, it should be appreciated that
the LEDs may be located on the same or adjacent sides. If on the
same side, the LEDs may be side by side, stacked vertically, or
separated. Further, some embodiments may employ multiple white
LEDs, multiple multicolor LEDs, or a white LEO and several
color-emitting LEDs. In one sample embodiment, two white LEDs may
be used. The LEO light guide may have two angled corners 1110, 1120
extending between sides of the package 1100, as shown to best
effect in the top-down view of FIG. 11. The white LEDs 1130, 1140
may be positioned adjacent these angled corners so that light may
be emitted into the interior of the package 1100 and thus into a
light guide (not shown). Because each angled corner extends at
approximately 135 degrees from the adjacent sidewalls, the white
light emitted by the white LEDs may be evenly dispersed and mixed.
It should be appreciated that a single light guide may be used for
both white LEDs or both white LEDs and the multicolor LEO 1150.
Again, multiple single-color LEDs may be used in place of the
multicolor LEO. Likewise, certain embodiments may use two
multicolor LEDs and a single white LEO and reverse the positions
depicted in FIG. 11. Further, in certain embodiments the angle of
the corner(s) may be more or less than 135 degrees. As yet another
alternative, the package 850 may include angled corners and the
LEDs may sit outside the package.
[0063] Although the present invention has been described with
respect to particular apparatuses, configurations, components,
systems and methods of operation, it will be appreciated by those
of ordinary skill in the art upon reading this disclosure that
certain changes or modifications to the embodiments and/or their
operations, as described herein, may be made without departing from
the spirit or scope of the invention. Accordingly, the proper scope
of the invention is defined by the appended claims. The various
embodiments, operations, components and configurations disclosed
herein are generally exemplary rather than limiting in scope.
* * * * *