Circuit to protect a light element

Details Circuit to protect a light element Circuit to protect a light element

2002-10-28

2004-02-03

Wong, Don (Department: 2821)

Electric lamp and discharge devices: systems

With radiant energy sensitive control means

C315S159000, C361S088000, C372S038030

Reexamination Certificate

active

06686697

ABSTRACT:

CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of Korean Application No. 2001-77419 filed Dec. 7, 2001, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical recording reproducer, and more particularly, to a circuit to protect a light element to prevent a breakdown of a laser diode (LD) when electric static discharge (ESD) occurs.
2. Description of the Related Art
Widely used laser diodes (LDs), which are one of essential components of optical apparatuses, are sensitive to static electricity. Thus, steps to prevent static electricity have been taken and managed in a process of manufacturing LDs. However, it is impossible to completely prevent static electricity due to various conditions or environments. LD manufacturers have somewhat different electrostatic levels for the LDs, which are lower than an electrostatic level of about 60V, a level that is allowed in processes to manufacture the LDs.
FIG. 1
is a diagram of a conventional light element driving circuit which includes a laser diode
100
and a drive IC
101
to drive the laser diode
100
. If the laser diode
100
is exposed to a surge voltage or static electricity, there is a high probability that the laser diode
100
will break down.
SUMMARY OF THE INVENTION
Various objects and advantages of the invention will be set forth in part in the description that follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
To solve the above-described problems, in accordance with an embodiment of the present invention, there is provided a circuit to protect a light element exposed to static electricity to reduce a probability that the light element breaks down.
In accordance with an embodiment of the present invention, there is provided a circuit to protect a light element in a drive to control an operation of the light element which radiates light onto a disc. Here, the drive includes a switch between an active node of the light element and a predetermined potential so that the switch is short-circuited in a normal state, but is open when the drive operates.
In accordance with a second embodiment of the present invention, there is provided a circuit to protect a light element in an apparatus to control an operation of the light element which radiates light onto a disc. The circuit includes a switching unit and a light element drive. The switching unit is connected between an active node of the light element and a predetermined potential. The light element drive controls the operation of the light element and outputs a switching control signal to open the switching unit when a command to operate the light element is input from an outside.
The switching unit is short-circuited in a normal state.
In accordance with a third embodiment of the present invention, there is provided a circuit to protect a light element in an apparatus to control an operation of the light element which radiates light onto a disc. The circuit includes a switching unit and an electrostatic voltage sensor. The switching unit is connected between an active node of the light element and a predetermined potential. The electrostatic voltage sensor senses an electrostatic voltage occurring in the apparatus and outputs a switching control signal to short-circuit the switching unit when the electrostatic voltage is greater than a reference value.
These together with other aspects and advantages which will be subsequently apparent, reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part thereof, wherein like numerals refer to like parts throughout.


REFERENCES:
patent: 4751524 (1988-06-01), Balchunas
patent: 5144631 (1992-09-01), Okino
patent: 6100907 (2000-08-01), Uffel
patent: 6445670 (2002-09-01), Oshima
patent: 6504857 (2003-01-01), Iwazaki
patent: 9-288840 (1997-11-01), None

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