Dynamic information storage or retrieval – Condition indicating – monitoring – or testing – Including radiation storage or retrieval
Reexamination Certificate
2002-08-29
2004-02-17
Hindi, Nabil (Department: 2655)
Dynamic information storage or retrieval
Condition indicating, monitoring, or testing
Including radiation storage or retrieval
Reexamination Certificate
active
06693865
ABSTRACT:
This application incorporates by reference of Taiwan application serial no. 090121387, filed Aug. 29, 2001.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates in general to a protection method for preventing optical disk drives from Laser leakage, and more particularly to a protection method that prevents optical disk drives from Laser leakage by means of a switch detector and an electronic detecting method.
2. Description of the Related Art
Living in today's society where science and technology advance and change rapidly, optical disk drive has become an indispensible appliance to modern people. Among the optical disk drives available today, the Compact Disk-Read Only Memory drive (CD-ROM drive) and the Digital Versatile Disk player (DVD-ROM player) are two products which have won great popularity. For example, the users can listen to beautiful music from CD using a CD-ROM drive or watch touching movies using a DVD player which is indeed very convenient. The optical disk drives used in the abovementioned purposes are either open-top type optical disk drives or tray type optical disk drives. Both two types have an exposed pickup head. Lacking any shielding protection, it is possible that Laser rays emitted by the pickup head would leak out and thus cause harm to users which is very dangerous. In consideration of preventing Laser leakage and protecting users, an extra switch detector is added to the abovementioned optical disk drives. Laser rays will be emitted only if the top cover of an open-top optical disk drive or the tray of a tray optical disk drive are detected to be closed. Under the circumstance that the first switch detector fails to work properly, the extra one helps to reduce the possibility of mistaking the top cover of an open-top optical disk drive or the tray of a tray optical disk drive to be closed. Hereinafter, the slim type (notebook personal computer) tray optical disk drive will be used as an example with attached drawings.
Please refer
FIG. 1
, a top view of a tray type optical disk drive with its tray being open. In
FIG. 1
, the optical disk drive
100
comprises a casing
102
, a motherboard
104
, a control unit
106
, a switch detector
108
, a tray
110
, a spindle motor
112
and a pickup head
114
. The tray
110
is installed inside the casing
102
in a movable way, and can depart from or slide into the casing
102
according to the directions of the arrow
150
shown in FIG.
1
. So the open/close status of the tray
100
allows users to displace CDs. When the optical disk drive opens its tray, i.e. the tray
110
is opened, the user can place the CD
120
on the circular disk carriage
116
of the tray
110
(for instance, along the direction of the arrow
160
shown in FIG.
1
). The center point hole
122
of the CD
120
joints with the spindle motor
112
at the center point of the disk carriage
116
. When the spindle motor
112
revolves, the CD
120
will be driven to revolve accordingly. The pickup head
114
is installed at the channel
118
of the tray
110
in a movable way, and moves back and forth at the channel
118
along the direction of the arrow
170
emitting Laser rays to detect whether the CD
120
has been placed on the tray
110
or not and read the data stored in the CD
120
. Besides, the motherboard
104
, control unit
106
and the switch detector
108
are installed inside the casing
102
. Of which, the control unit
106
and switch detector
108
are installed on the motherboard
104
and are coupled with it, whereas the control unit
106
is coupled with the switch detector
108
.
When the optical disk drive
100
closes its tray, the tray
110
slides towards the casing
102
along the direction of the arrow
150
shown in
FIG. 1
until the switch detector
102
is touched. After having been touched by the tray
110
, the switch detector
108
will send a close-status signal to the control unit
106
indicating the optical disk drive is closed. Next, the control unit
106
receives the closed-status signal and controls the pickup head
114
and the spindle motor
112
accordingly. Whether the CD
120
is placed on the tray
110
or not will be detected when the CD
120
is driven to revolve by the spindle motor
112
. Having confirmed the existence of a CD, the pickup head
114
emits Laser rays and starts to read data from the CD
120
. Along the direction of the arrow
170
shown in
FIG. 1
, the pickup head
114
moves step by step and emits Laser rays continually reading data stored in the CD
120
from inner tracks outwardly.
It is noteworthy that under normal circumstances when the tray is open, it will not touch the switch detector
108
and not any signal will be sent to the control unit
106
. When the tray
108
is closed, the switch detector
108
, being touched by the tray
110
, will generate and send a close-status signal to the control unit
106
allowing the control unit
106
to control the pickup head
114
to emit Laser rays according to the close-status of the optical disk drive and the feedback signal of the spindle motor
112
. With the tray
110
being enclosed inside the casing
102
, the Laser leakage that causes harm to users can thus be prevented under the shielding protection of the casing
102
and the CD
120
.
The above discussion is limited to the tray type optical disk drives only. As for the open-top optical disk drive, the discussion is as follows. The open-top optical disk drive has a structure similar to that of a tray type optical disk drive. The difference between them is that the open-top optical disk drive has a fixed tray in which a CD is accommodated with a top cover situated on top of it. When the top cover is opened, the user can place the desired CD on it; after that, the top cover is closed and the optical disk drive will be used to read the CD. Therefore, to achieve the same detecting function, i.e. detecting the close/open status of the optical disk drive and to prevent Laser leakage, the user only needs to install a switch detector in such a way that it can be initiated when the top cover closes to the casing.
However, after having been in service for a period of time, the motherboard
104
will start to experience short-circuits because of rusty circuits. The control unit
106
might mistake short-circuits for the close-status signal sent by the switch detector and continually control the pickup head to emit Laser rays. As a consequence, Laser rays will be emitted with an open and empty tray
110
resulting in Laser leakage which causes harm to users. Since the switch detector
108
is a mechanic structure, it is apt to develop aging and mechanic breakdown after having been in service for a period of time. Consequently, the switch detector
108
is likely to mistake the open-status of the tray
110
for the close-status and send the close-status signal to the control unit
106
. The control unit
106
will then control the pickup head
114
to emit Laser rays according to the close-status received resulting in an open and empty tray
110
with Laser leakage which is indeed very dangerous and might cause harm to users.
In order to prevent the failure of the switch detector
108
which leads to Laser leakage, an extra switch detector is added to satisfy safety requirements. Generally speaking, an optical disk drive always uses two switch detectors to reduce the probability of errors. Apart from increase in production cost, the second switch detector, being a mechanic structure, cannot be free from aging and mechanic breakdown.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a protection method that prevents Laser leakage of an optical disk drive. Its electronic detecting method, which replaces the design of adding a second switch detector to a conventional optical disk drive, not only helps to reduce production cost but also effectively detects whether a CD has been placed into the optical disk drive or not, thus avoiding Laser leakage that causes harm to users.
According to the object of the inventi
Asustek Computer Inc.
Hindi Nabil
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