Active solid-state devices (e.g. – transistors – solid-state diode – Incoherent light emitter structure – In combination with or also constituting light responsive...
Reexamination Certificate
2001-09-25
2004-12-21
Cuneo, Kamand (Department: 2827)
Active solid-state devices (e.g., transistors, solid-state diode
Incoherent light emitter structure
In combination with or also constituting light responsive...
C257S079000, C257S080000, C257S098000, C257S099000, C257S686000
Reexamination Certificate
active
06833563
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to increasing the utilization of light emitting diodes (LEDs) mounted on printed circuit boards. More particularly, the present invention relates to allowing multi-stack surface mounted LEDs and decreasing the board space required by the LEDs.
2. Description of the Related Art
In a conventional computer system, printed circuit boards (PCBs) are used to mount semiconductor chips and other electronic components. Computers typically use several types of PCBs including motherboards and various expansion boards. The motherboard usually contains the central processing unit (CPU), memory, and controllers for the computer. Examples of expansion boards include graphics, video, and disk drive cards, as well as local area network (LAN) cards.
An LED is an electronic device that radiates light when electricity is passed through it. LEDs are extremely versatile and thus, widely used in various electronic fields. For example, LEDs are good for displaying images because they can be relatively small, and they do not burn out. With regard to computers, LEDs are mounted on PCBs to function as indicators. For example, an LED mounted on an expansion board may radiate light in different colors to indicate the status of the board. A green light typically indicates a good status, while a red light typically implies that something is wrong.
FIG. 1A
is a frontal view and
FIG. 1B
is a side view of a typical multi-stacked through hole mount (THM) LED module
10
mounted on a PCB
12
. LED package
10
includes three LEDs
14
,
16
, and
18
coupled to a THM housing
20
. THM housing
20
is usually mounted about a half a millimeter off PCB
12
. Each LED
14
,
16
, and
18
includes a cathode and anode wire extending outside THM housing
20
for connecting it with PCB
12
. Because the wires are bent to allow LEDs
14
,
16
, and
18
to emit light along the same plane as PCB
12
, the LEDs are known as right angle LEDs.
While LED package
10
has generally been an adequate apparatus to house LEDs in computer systems, it has many limitations. As can be seen from
FIGS. 1A and 1B
, the structure of LED package
10
is not very sturdy. Because PCBs are still often manipulated by hand and because LED package
10
juts out from the surface of PCB
12
when mounted, it is fragile and quite easy to break by accident. THM-LED packages are also frequently broken by test equipment. Furthermore, as computer technology continues to improve, PCBs become more and more densely populated with chips and other components, adding to the difficulty. One form of sturdier LED package that has been developed is known as a surface mount device (SMD) LED package.
FIG. 2A
is a top view and
FIG. 2B
is a back view of a typical SMD-LED package
22
. Unlike THM-LED package
10
, SMD-LED package
22
is mounted directly onto PCB
24
, rising only slightly above the surface of the board. SMD-LED package
22
also includes a LED die
26
encased in a SMD housing
28
, which includes a layer of epoxy
30
so that LED die
26
is able to emit light through it. In addition, the bottom of SMD housing
28
is also a form of circuit board material and includes a cathode surface
32
, a reinforcing non-electrode pin
34
, and an anode surface
36
, all of which are soldered to PCB
24
. The actual solder material is not illustrated for purposes of clarity in FIG.
2
B.
As is shown from
FIGS. 2A and 2B
, SMD-LED packages have many advantages over traditional THM-LED packages. A SMD-LED package is much sturdier and smaller by comparison. Therefore, in addition to minimizing breakage, SMD-LED packages use much less space, allowing for more efficient utilization of the PCB. Furthermore, SMD-LED packages are much easier to manufacture. Automated machines are able to “pick and place” surface mounted devices at phenomenal rates.
However, a major problem with SMD-LED packages is that they are not able to house and utilize multiple LEDs, unlike the THM-LED packages shown in
FIGS. 1A and 1B
. To display multiple signals, multiple SMD-LED packages must be used instead of a single multi-stacked THM-LED package, requiring far too much valuable space on a PCB. In addition, the inability to use multiple LEDs is a major disadvantage because there are many applications where PCBs need to send multiple signals to transmit information to either a technician or an end user.
In view of the foregoing, it is desirable to have a method and apparatus that provides for a multi-stacked SMD-LED package to reduce the risk of breakage. It is also desirable to have a multi-stacked SMD-LED package to display multiple status signals so that space can be more efficiently used on a PCB.
REFERENCES:
patent: 5280184 (1994-01-01), Jokerst et al.
patent: 5324962 (1994-06-01), Komoto et al.
patent: 5396086 (1995-03-01), Engels et al.
patent: 5528474 (1996-06-01), Roney et al.
patent: 6093940 (2000-07-01), Ishinaga et al.
patent: 6392294 (2002-05-01), Yamaguchi
patent: 2002/0021725 (2002-02-01), Abe
patent: 2002/0029071 (2002-03-01), Whitehurst
patent: 2002/0030444 (2002-03-01), Muller-Mach et al.
patent: 2002/0030445 (2002-03-01), Fukasawa
patent: 2002/0043923 (2002-04-01), Natori
patent: 1103759 (2001-05-01), None
patent: 1107321 (2001-06-01), None
patent: 363030271 (1988-02-01), None
patent: 01-98273 (1989-04-01), None
patent: 402260670 (1990-10-01), None
patent: 02-296380 (1990-12-01), None
patent: 404137570 (1992-05-01), None
patent: 05-131499 (1993-05-01), None
patent: 05-152606 (1993-06-01), None
patent: 05-315653 (1993-11-01), None
patent: 06085327 (1994-03-01), None
patent: 408264841 (1996-10-01), None
patent: 09321345 (1997-12-01), None
patent: 11161416 (1999-06-01), None
patent: 2000188358 (2000-07-01), None
patent: 1347831 (1996-07-01), None
patent: WO 9941785 (1999-08-01), None
Boyd Patrick D.
LaValle Al
Rinaldi Jarett L.
Cuneo Kamand
Mitchell James M.
Steiner Paul E.
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