The present invention relates to improvements for disc players and
in particular, to an improved body design for the disc player.
In the following specification the term disc player will be used
to refer to compact disc players, recordable compact disc players (CDR), re-writable
compact disc players (CDRW) and DVD players, both portable and fixed, all of which
are suitable for incorporating the disclosed inventions.
The prior art teaches of disc players that comprise disc enclosures
and separate chassis employed to mount a spindle motor and an optical pick-up unit
(OPU). Mounting the spindle motor and OPU on a chassis provides a method for controlling
the position of the OPU with respect to a rotating disc.
An inherent problem of such chassis is that they are prone to transmit
vibrations to the rest of the disc player. These vibrations result from the excitation
caused by the disc rotation. The chassis are also subject to disturbances themselves
from external vibrations, which can effect the overall performance of the disc
To overcome problematic features of such internal and external vibrations
the chassis is normally connected to the disc enclosure via rubber anti-vibration
(AV) mounts. These AV mounts are additional components that require the development
of mould tools in order to provide for their manufacture, as well as their specific
construction and incorporation within the assembly procedure. Such procedures
add significant cost to the manufacture process, thus resulting in additional costs
being passed onto the consumer.
A further problematic design feature also results from employing
a separate chassis and disc enclosure. Due to tolerance levels required in separately
manufacturing such components the clearance between the disc and the inner surface
of the disc enclosure must be maintained at a minimum value. This significantly
hinders the overall miniaturisation of such disc players. In addition, wind drag
resulting between the spinning disc and the disc enclosure is directionally proportional
to the dimensions of the disc enclosure. Therefore the smaller the disc enclosure,
the smaller the wind drag. A small wind drag is advantageous in that the current
required to drive the spindle motor is reduced. This has particular relevance
for portable disc drives that draw current from a battery, as the level of current
drawn affects the battery lifetime.
A further problematic design feature taught in the prior art relates
to the securing of the disc enclosure. Such securing means, employ latches that
lock when the lid of the enclosure is closed. In order to gain access to the disc
enclosure, for the placing or removing of a disc, requires the operator to manually
overcome the latch.
Within such systems the manual opening of the disc player is not
related to the rotation of the disc. Therefore, if the lid is inadvertently opened
when the disc player is writing data to a disc the laser safety cut off will immediately
stop the write action. Written data will therefore not end by the correct closing
procedure for the writing session. Without proper closure of the session the data
just written, and all other data on the disc, will not be accessible at a later
date and so is effectively lost.
In addition, if the user has access to the disc while it is spinning
at high speed there is a risk of personal injury if the user were to touch the
edge of the disc. A point to note is that this is not such a problematic feature
in traditional portable CD players where the discs spin at 15Hz however it does
become a concern in relation to CDRWs where discs can be driven at up to 120Hz.
It is also. possible that a user's hand acting as a break on the spinning disc
could cause damage to the spindle motor.
In order to overcome some of these problematic features, the prior
art teaches of disc players which incorporate a disc brake employed to stop the
disc spinning as soon as the lid is opened. However, these brakes can produce
debris and contamination as they come into contact with the disc. They also make
placement of the disc on the spindle motor more difficult as the break is required
to be moved aside before the disc is deployed.
CDRW or CDR players which employ manually operated lids may also
employ write locks to prevent the lid being inadvertently opened. However, these
write locks require their own motors, solenoids and gear mechanisms in order to
activate the locks when the lid is closed.
It is an object of the present invention to provide a disc player
that comprises a one-piece disc enclosure therefore, enhancing the miniaturisation
of the disc player while reducing the cost of manufacture.
According to a first aspect of the present invention there is provided
a disc player comprising a disc enclosure and a chassis section, wherein the disc
enclosure and the chassis section are formed as a single integrated unit so enabling
the overall miniaturisation of the disc player.
Most preferably chassis section comprises a damping system located
at the interface between the chassis section and the disc enclosure wherein the
damping system acts to dampen the vibrations of the chassis section when the disc
player is in operation.
Preferably the damping system comprises a plurality of damping means
connected between the disc enclosure and the chassis section.
Preferably the damping means comprises a plastic spring.
Preferably the disc enclosure comprises a spindle motor locating
aperture and an optical pick up unit locating aperture.
Preferably the chassis section further comprises a spindle motor
and an optical pick up unit.
Optionally the disc enclosure further comprises a lid locking mechanism.
Embodiments of the present invention will now be described by way
of example only with reference to the accompanying figures:
- Figure 1 presents a schematic illustration of disc player in accordance with
the present invention;
- Figure 2 presents a schematic illustration of the underside of the base of
the disc player, with a bottom section and a locking mechanism removed;
- Figure 3 presents a schematic illustration of a section of Figure 3 with the
locking mechanism present and in:
- a) a locked position; and
- b) an unlocked position.
- Figure 4 presents a schematic illustration of a wind vane of the locking mechanism.
Referring initially to Figure 1 a disc player 1 is presented in accordance
with the present invention. The disc player 1 can be seen to comprise a lid 2,
a base 3, a spindle motor 4 and an optical pick-up unit (OPU) 5. On the perimeter
of the base 3 is a locking mechanism 6 (described in detail below) and a series
of operating controls 7 for the disc player 1.
Further details of the base 3 are presented in Figure 2. Here the
base 3 is viewed from the underside in the absence of a bottom section and the
locking mechanism 6. The base 3 can be seen to further comprise a chassis section
8, a wind vane locating pin 9 and fixing pins 10 for securing the bottom section.
The chassis section 8 comprises an OPU locator 11, a spindle motor locator 12
and an integrated damping system 13. The integrated damping system 13 itself comprising
five moulded plastic springs 14 located at the perimeter of the chassis section
Referring to Figure 3, details of the locking mechanism 6 can be
seen. The locking mechanism 6 comprises a wind vane 15, shown in isolation in Figure
4, an air vent 16 and a latch 17. The latch further comprises a catch 18 and a
side arm 19, while the wind vane 15 comprises a locator 20, a side arm 21 and a
bias means (not shown). With the wind vane 15 located such that the locator 20
interacts with the wind vane locating pin 9, the wind vane 15 is free to pivot
between a locked position and an unlocked position.
The locking mechanism 6 operates on the following principal. Air
pressure generated from the internally spinning disc is employed to activate the
wind vane 15, thus moving it from the unlocked position to the locked position.
In the locked position the wind vane 15 prevents the manual operation of the latch
17 hence stopping the lid 2 from being opened. When the disc spins the air is
drawn to the perimeter of the base 3 thus creating an air pressure build up around
the edge of the disc. This air passes through the air vent 16 and wafts against
the wind vane 15 causing it to pivot about the wind vane locating pin 9. As long
as the disc remains spinning, the airflow is maintained and locking mechanism
6 is maintained in the locked position, preventing the lid 2 from being opened.
When the operator requires to open the lid 2, they manually activate the software
to stop the disc, thus resulting in the air pressure acting against the wind vane
15 subsiding and so the bias means acts to return the wind vane 15 to the unlocked
The present invention has the advantage that the incorporation of
an integrated damping system 13 within the base 3 of the disc player 1 eliminates
the requirement for the manufacture and assembly of separate rubber AV mounts.
Additionally, because the damping system 13 is integrated with the base 3, this
component can be manufactured to with greater accuracy, such that that the allowed
clearance between the disc and the inner surface of the base 3 can be reduced.
This reduction enhances the miniaturisation of the dimensions of the disc player.
As a direct result of this miniaturisation the overall wind drag experienced by
the disc is reduced, thus having the effect of reducing the current required to
drive the spindle motor. An obvious advantage of this will be an increase in the
lifetime of battery cells employed by portable disc players.
Further advantages of the present invention are that the locking
mechanism 6 prevents the need for a disc break, since the disc will always be stationary
before the lid 2 is opened. The locking mechanism 6 also removes the need for
the electronics normally associated with a write lock. In addition, since the locking
mechanism 6 is activated by the airflow generated by a spinning disc there is
no need for it to use any electrical components such as motors, solenoids or associated
gear mechanisms. As the locking mechanism 6 draws no current it provides a particularly
attractive feature for portable devices that employ battery power sources.
A yet further advantage of the present invention is that as there
are no wires or connectors required for the operation of the locking mechanism
6 the disc player 1 is both easier and cheaper to assemble.
The foregoing description of the invention has been presented for
purposes of illustration and description and is not intended to be exhaustive or
to limit the invention to the precise form disclosed. The described embodiments
were chosen and described in order to best explain the principles of the invention
and its practical application to thereby enable others skilled in the art to best
utilise the invention in various embodiments and with various modifications as
are suited to the particular use contemplated. Therefore, further modifications
or improvements may be incorporated without departing from the scope of the invention