Optical: systems and elements – Deflection using a moving element – Using a periodically moving element
Reexamination Certificate
1998-08-28
2001-11-13
Pascal, Leslie (Department: 2633)
Optical: systems and elements
Deflection using a moving element
Using a periodically moving element
C359S199200, C359S199200
Reexamination Certificate
active
06317235
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to infrared communications systems and, more specifically, to a Method and System for Preventing Burn-out of Infrared Transmitter Diodes.
2. Description of Related Art
As technology becomes continually more accessible to the “common man,” the ability to use, store, transfer and otherwise manipulate information has become the focus of most businesses as well as for the individual consumer. Access to the information resources is commonly by some sort of network system, including World Wide Web, “Intranets”, local area networks, wide area networks, as well as corporate databases.
While the conventional method for connecting to one of these information networks has been via cable and wire, as the reliance upon connectivity to information has deepened, the desire to gain such access from mobile or portable devices has strengthened. These portable devices, such as Personal Digital Assistants, hand-held computers, cellular telephones, and even digital cameras are now being connected to each other and to networks via Infrared Data Communications. In fact, it is virtually impossible to purchase a notebook computer today that does not include an Infrared Data Communications assembly resident within it.
FIG. 1
depicts a significant problem with the conventional Infrared-enabled appliance; it is an illustration of such an appliance
10
. In its pertinent form, the typical Ir-enabled appliance
10
includes an infrared transceiver system
12
that is, for the purposes of this discussion, provided electrical power
14
by a power supply means
16
, such as an internal battery or an external cable. Within the transceiver system
12
, among other devices and circuits, there are typically at least one infrared transmitter
18
(or transmitter array) and at least one receiver
20
(or receiver array).
Under normal transmission conditions, when the Central Processing Unit
22
(or other control device or system) sends data to the communications controller
24
for transmission by the Ir transmitter
18
, the controller
24
converts the data into a transmit data signal
26
. A transmit data signal
26
is essentially a string of “power-off's” and “power-on's”, which represent digital zero's and one's, respectfully. A “power-on” causes the transmitter
18
to emit an infrared signal
28
. While transmitting normally, these “power-on's” and “power-off's” are of very short duration—on the order of less than one-tenth (0.1) second each.
Under certain power-up modes, however, the appliance
10
may direct or otherwise cause the power
14
to be energized to the transceiver
12
, and more specifically, to create a “power-on” to the transmitter
18
for a substantial period of time. Furthermore, it is somewhat common for the CPU
22
to “lock up” or otherwise go into a “hang mode” during a variety of operations (or error conditions)—sometimes this, too can create a “power-on” condition in the transmitter
18
.
The problem addressed by the present invention relates to the damage incurred by the transmitter
18
when the appliance is undergoing one of these power-up modes. It has been observed that the transmitter diode temperature
28
(represented by the thermometer here) of the typical infrared transmitter
18
will reach dangerously high levels if the transmit data signal
26
to the transmitter
18
is left in the “power-on” condition for periods in excess of 5 to 10 seconds. After being subjected to these high temperatures
22
, particularly on a repeated basis, the typical transmitter
18
will fail due to thermal burn-out. What is needed is an improved transceiver system and method to prevent transmitter over-temp and subsequent failure due to prolonged “power-up” conditions.
SUMMARY OF THE INVENTION
In light of the aforementioned problems associated with the prior methods and devices, it is an object of the present invention to provide a Method and System for Preventing Burn-out of Infrared Transmitter Diodes. The preferred method and system will detect when the Ir transmitter(s) are approaching or have achieved an overtemperature condition. Once an overtemperature condition is detected, the preferred system should interrupt electrical transmit power to said transmitter until such time as said overtemperature condition is dissipated. It is a further object that the system and method send a standby signal to the Central Processing Unit or communications controller when an overtemperature condition is detected. It is a still further object that the system emit status signals perceptible to the human senses when normal and abnormal temperature conditions are detected in the transmitter.
REFERENCES:
patent: 5073838 (1991-12-01), Ames
patent: 5118964 (1992-06-01), McArdle
patent: 5379145 (1995-01-01), Nodine
patent: 5602860 (1997-02-01), Masonson
patent: 5663823 (1997-09-01), Suzuki
patent: 5786921 (1998-07-01), Wang et al.
patent: 5844928 (1998-12-01), Shastri et al.
patent: 5978395 (1999-11-01), Nomura
Pascal Leslie
Phan Hanh
Steins & Associates
Zilog Inc.
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