Dynamic information storage or retrieval – Specific detail of information handling portion of system – Radiation beam modification of or by storage medium
Reexamination Certificate
1999-10-08
2001-10-30
Huber, Paul W. (Department: 2651)
Dynamic information storage or retrieval
Specific detail of information handling portion of system
Radiation beam modification of or by storage medium
C369S044150
Reexamination Certificate
active
06310852
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an optical recording/reproducing apparatus that optically writes information on or optically readouts information from a recording medium.
BACKGROUND OF THE INVENTION
This kind of optical recording/reproducing apparatus optically writes information on or optically readouts information from an optical disk such as MD (a mini disc), a magneto-optical disk, or the like while driving an objective lens in two axial directions, namely an optical axial direction (a focusing direction) perpendicular to a recording surface of the optical disk and a radial direction parallel to the recording surface, to compensate shifts in focusing due to wobbling of the optical disk or in tracking due to deviation or the like of the optical disk.
Recently, in an optical recording/reproducing apparatus provided with an objective-lens actuator for driving an objective lens in a focusing direction and in a radial direction via a plurality of elastic members arranged almost in parallel to one another, a configuration in which a fixing member for attaching the elastic members is positioned between the objective lens and a light source to reduce the size of the whole apparatus mainly has been employed.
An example of the above-mentioned conventional optical recording/reproducing apparatus will be described with reference to the drawings as follows.
FIG. 6
is a plan view showing a conventional optical recording/reproducing apparatus.
FIG. 7
is a sectional side view showing the conventional optical recording/reproducing apparatus.
As shown in
FIGS. 6 and 7
, the conventional optical recording/reproducing apparatus comprises: a light receiving and emitting device
61
including a light source for emitting divergent optical beams
63
, a focusing-error-signal detector, a tracking-error-signal detector, and an information-signal detector; a collimator lens
60
for converting the divergent optical beams
63
emitted from the light source in the device
61
into parallel beams; a mirror
59
for orthogonally refracting the optical beams
63
converted to the parallel beams by the collimator lens
60
; an objective lens
51
for converging the orthogonally refracted optical beams
63
onto a disk
64
; an objective-lens actuator for driving the objective lens
51
in a focusing direction F and in a radial direction R of the disk
64
; and an optical block
62
for fixing the device
61
, the mirror
59
, and the objective-lens actuator. A movable part comprising a lens holder
52
for holding the objective-lens
51
, a focusing coil
54
, and a pair of tracking coils
55
in the objective-lens actuator is attached to a fixing member
57
via four suspensions
56
of elastic members that are arranged in parallel to one another and that are formed of stainless steel, phosphor bronze, beryllium copper, or the like. The fixing member
57
is fixed to a base
58
that is further fixed to the optical block
62
. In this case, the fixing member
57
is provided with an opening portion
57
a
for avoiding the interference with the optical beams
63
. The fixing member
57
is positioned between the objective lens
51
and the device
61
with respect to a tangential direction T (the direction perpendicular to the focusing direction F and the radial direction R), thus reducing the size of the optical recording/reproducing apparatus in the tangential direction T. A magnetic circuit is formed of the base
58
and a pair of magnets
53
, and the focusing coil
54
and the tracking coil
55
are positioned in a space within the magnetic circuit. Thus, a magnetic field is applied to the focusing coil
54
and the tracking coil
55
.
The operation of the optical recording/reproducing apparatus formed as described above will be described as follows.
The divergent optical beams
63
emitted from the light source in the device
61
are converted into parallel beams by the collimator lens
60
. The parallel beams are reflected by the mirror
59
and enter into the objective lens
51
, thus being converged on the disk
64
. Light reflected from the disk
64
is converged in the signal detectors on the device
61
through the reverse path, thus detecting signals. In this case, the objective lens
51
is driven by the focusing coil
54
and the tracking coil
55
in the focusing direction F and in the radial direction R respectively so as to follow wobbling or deviation of the disk
64
.
In further reducing the size of the optical recording/reproducing apparatus having such a configuration as mentioned above, there are two problems of the interference between the optical beams
63
(parallel beams) that came out from the collimator lens
60
and the fixing member
57
by which the objective-lens actuator is fixed with respect to the radial direction R and the interference between the collimator lens
60
and the fixing member
57
with respect to the tangential direction T.
With the reduction in size of the optical recording/reproducing apparatus, the length of the suspensions
56
for supporting the movable part also is shortened and sufficient strength against disturbance vibration or impact caused when the optical recording/reproducing apparatus is dropped cannot be obtained. Thus, there is a fear of causing deformation or breakage of the suspensions
56
.
SUMMARY OF THE INVENTION
It is an object of the present invention to solve the above-mentioned conventional problems and provide an optical recording/reproducing apparatus that can be further reduced in size and can improve the strength of suspensions of elastic members for supporting a movable part against disturbance vibration or impact caused when the optical recording/reproducing apparatus is dropped.
In order to attain the above-mentioned object, a recording/reproducing apparatus of the present invention comprises: a light source for emitting divergent optical beams; a collimator lens for converting the optical beams emitted from the light source into parallel beams; an objective lens for converging the optical beams converted to the parallel beams by the collimator lens onto a recording medium; an objective-lens actuator having a mechanism for driving the objective lens in an optical axial direction perpendicular to a recording surface of the recording medium and in a radial direction parallel to the recording surface; and a signal detector for detecting various signals on the recording medium. The optical recording/reproducing apparatus of the present invention is characterized in that the objective-lens actuator is supported by elastic members that are attached to a lens holder for holding the objective lens at their one ends and to a fixing member at their other ends to enable the lens holder to move in the optical axial direction and in the radial direction, and the collimator lens is positioned between the objective lens and the fixing member with respect to the direction perpendicular to the optical axial direction and the radial direction. According to the configuration of this optical recording/reproducing apparatus, the distance from the center of the objective lens to an end face of the collimator lens can be shortened compared to that in the conventional optical recording/reproducing apparatus. Further, since the fixing member is positioned in divergent beams between the light source and the collimator lens, an opening portion provided in the fixing member to avoid interference with the optical beams can be reduced in size compared to that in the conventional optical recording/reproducing apparatus. Therefore, the optical recording/reproducing apparatus can be further reduced in size with respect to the direction perpendicular to the optical axial direction and the radial direction. In addition, the optical recording/reproducing apparatus also can be reduced in size with respect to the radial direction. Furthermore, the length of the elastic members for attaching a movable part of the objective-lens actuator to the fixing member can be lengthened compared to that in the conventional optical recording/repr
Aikoh Hideki
Furukawa Hiromichi
Nakata Hideki
Tomita Hironori
Huber Paul W.
Matsushita Electric - Industrial Co., Ltd.
Merchant & Gould P.C.
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