JPH06302001A - Optical pickup, optical recording / reproducing device, and cartridge - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve the reliability of an optical recording / reproducing device, prevent mechanical failure, and make it thinner. A stopper is provided at a position closer to an inner circumference or an outer circumference of an optical recording medium with respect to an optical axis of the light condensing element, the stopper protruding toward the optical recording medium from the light condensing element. This stopper is driven by an actuator integrally with the light collecting element. The focus servo pull-in operation of the actuator is performed near the innermost circumference or the outermost circumference of the information recording area of the optical recording medium. Further, the tension direction of the suspension of the actuator matches the rotation direction of the optical recording medium. As another method, a contact surface that restricts the focusing operation amount of the actuator is formed on the cartridge. [Effect] Since the condensing element and the optical recording medium indirectly collide with each other in an area other than the information recording area, there is no damage to the optical recording medium or the optical recording / reproducing apparatus, which causes poor quality. . Further, the working distance (WD) of the light collecting element can be shortened to the limit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording / reproducing device such as a digital audio disc (so-called compact disc) player or an optical disc device which is an external recording device, and an optical pickup mounted in these devices.

[0002]

2. Description of the Related Art These conventional optical recording / reproducing apparatuses have no means for preventing a condenser element, that is, an objective lens, from colliding with the surface of an optical recording medium.

[0003]

However, in the conventional case, when the initial pull-in of the focus servo fails, as shown in FIG.
The surface 1 of the optical recording medium 10 which is revolving and rotating in the (+) direction.
Since it directly collides with 6, the contact part may be worn or deformed,
The scattered abrasion powder 25 adheres to the optical system and deteriorates the optical characteristics, which significantly deteriorates the recording and reproducing quality of information. In addition, the actuator 4 is driven by the frictional force with the optical recording medium 10.
In some cases, a force (or torque) in the C direction is applied to the holder 401 of No. 00 to cause the suspension 402, which is the movable support mechanism, to buckle and become inoperable. It should be noted that the condensing element 2 is configured so that such a defect is unlikely to occur.
In many cases, the working distance (WD) between the optical recording medium 10 and the optical recording medium 10 was made large, but this was merely a rest and it was against the demand for thinner and smaller devices. The present invention addresses these drawbacks.

[0004]

The structure of an optical pickup, an optical recording / reproducing apparatus and a cartridge according to the present invention for solving the above-mentioned problems are as follows: (1) a condensing element for forming a spot on an optical recording medium; An actuator for controlling the position of the element, and the element mounted on the actuator and driven integrally with the condensing element. The optical recording medium is located closer to the inner or outer circumference of the optical recording medium than the condensing element with respect to the optical axis of the condensing element. (2) The stopper described in (1) above is made of a resin or rubber, an elastomer, a felt, a non-woven fabric, or the like that is softer than the surface material of the optical recording medium. (3) The stopper described in (1) above is formed integrally with a holder that holds a light-collecting element, and (4) the optical pickup medium described in (1) above is used. The actuator is configured to perform the focus servo pull-in operation in the vicinity of the innermost circumference or the outermost circumference of the recording area. (5) Condensing element that forms a spot on the optical recording medium and position control of the condensing element The suspension, which is composed of an actuator and a stopper that is mounted on the actuator and is driven integrally with the light-collecting element, and that forms a movable support mechanism of the actuator, has a pulling direction that is substantially the same as the rotation direction of the optical recording medium, that is, the track groove direction. (6) A cartridge containing an optical recording medium, wherein a contact surface is formed near the innermost circumference and / or the outermost circumference of the optical recording medium, and the contact surface is the optical contact surface. (7) The cartridge is housed in the cartridge according to (6) above, which is a surface that regulates the stroke of the focusing operation of the pickup. A device for recording / reproducing information on / from an optical recording medium, characterized in that it is configured to perform a focus servo pull-in operation of an actuator in the vicinity of the innermost circumference or the outermost circumference of an information recording area of the optical recording medium. .

[0005]

According to the above construction, A) direct collision between the light collecting element (objective lens) and the optical recording medium is prevented, and the area other than the information recording area is contacted indirectly.

B) The working distance (WD) between the condensing element and the optical recording medium can be shortened to the utmost limit, and the optical system and the apparatus can be made compact and thin.

C) Prevent the destruction of the actuator.

It becomes possible.

[0009]

【Example】

(Embodiment 1) FIGS. 1 to 4 are a perspective view, a plan view, a side sectional view and a front sectional view showing the periphery of an optical pickup 150 of an optical recording / reproducing apparatus according to the present invention. 3 corresponds to the cross section AA shown in FIG. 2 and FIG. 4 corresponds to the step surface BB shown in FIG.

In each figure, 10 is an optical recording medium, that is, an optical disk, which is several hundred rpm to several thousand rpm in the direction of arrow R by a spindle motor (not shown).
It is rotating at the rotation speed of. The optical recording medium 10 has several hundreds of track grooves 14 from the innermost circumference 11 to the outermost circumference 12.
The number 0 to several 10,000 lines are formed to form the information recording area 13. The carriage 5 (FIG. 2) is guided by the guide shaft 2 and transferred in the T direction in the drawing by a seek mechanism (not shown). The optical pickup 150 includes the light collecting element 20.
Of the actuator 100, the optical head 110, the mirror 120 (FIG. 3) and the like for precisely controlling the position of the
The optical head 110 and the mirror 120 are stored and driven integrally. The optical pickup 150 is housed in a space surrounded by the carriage 5 and the cover 6, as shown in FIGS. Reference numeral 102 denotes a suspension forming a movable support mechanism of the actuator 100, and four thin leaf springs are used in this embodiment, but the present invention is not limited to this, and a wire spring may be used. One end 10 of the suspension 102
2a is a base 1 attached to the side surface of the yoke 106.
03, the other end 102b is attached to the holder 101, and the four pieces are deformed substantially in parallel to each other to move the holder 101
It is movably supported in two directions orthogonal to the (tracking) direction and the F (focusing) direction. A plurality of coils 104 are fixed to the holder 101, and the magnet 10 fixed to the yoke 106 is controlled by energizing the coils 104.
It is driven by electromagnetic action with 5. That is, the actuator 100 is configured as a so-called voice coil type actuator.

As a characteristic construction of the present embodiment, the direction of the suspension 102 extending from one end 102a on the fixed side to the other end 102b on the movable side coincides with the rotation direction R of the optical recording medium 10 as shown in FIG. , Coincides with the tangential direction of the track groove 14. In addition, a stopper 14 is provided around the condenser element (objective lens) 20 held on the upper surface of the holder 101.
0 is stuck. The stopper 140 has a protrusion 1
41 and a non-projecting portion 142 are formed, and project from the apex of the light-collecting element 20 by a distance L as shown in FIG. Also,
The protrusion 141 has a step on the inner peripheral side (right side in FIG. 4) of the optical recording medium 10 by a distance D from the center of the light converging element 20, that is, the optical axis 22. As the material of the stopper 140, it is possible to use resin, rubber, elastomer, felt, non-woven fabric, or the like having excellent wear resistance. In this embodiment, specifically, an integrally molded product made of nylon resin is used. In any case, it is softer than PC (polycarbonate) which is the surface material of the optical recording medium 10.

Next, the optical system of the optical pickup 150 will be described. In FIG. 3, the optical head 110 constitutes a small integrated optical head in which a laser chip of a light emitting element, a photodiode of a light receiving element, a hologram element which is a light beam separating means, etc. are housed, although not shown. .
The outward light flux 112 is emitted from the optical head 110, is bent by the mirror 120, and is then condensed by the condensing element 20 to form a spot 21 on the recording surface 15 of the optical recording medium 10. The backward beam 113 reflected by the recording surface 15 contains a signal component modulated by the information on the recording surface 15. The signal component is taken into the optical head 110 and detected by a light receiving element (not shown) to reproduce the signal. Is done. Further, the optical head 110 is arranged so that the condensing element 20 and the optical recording medium 10 are close
Focus error signal according to separation (focus error signal)
Also, it has a function of optically detecting a tracking error signal (tracking error signal) corresponding to the deviation in the tracking direction from the track groove. In the present embodiment, the detailed content itself of the optical head 110 is not important, so a detailed description thereof will be omitted, but these error signals are used as error signals for focus servo and track servo. The condensing element 20 constitutes a finite optical system as the only lens, and the distance from the light emitting point 111 inside the optical head 110 to the spot 21, that is, the so-called object point image point distance is about 15 mm.
And short. Further, the magnification of the condenser element 20, that is, the objective lens is
It is set to about 4: 1 in consideration of the detection accuracy of the focus error signal and the light beam utilization efficiency. If the lens shape is optimally designed so that the basic specifications of these optical systems are satisfied and the spot 21 is imaged in a nearly aberration-free state, the condensing element 20
The working distance (working distance WD) between the optical recording medium 10 and the surface 16 of the optical recording medium 10 is about 1 mm.

If the working distance (WD) of the condensing element 20 is such short, the condensing element 20 in the conventional case is the optical recording medium 1.
The risk of collision with 0 becomes very high,
As described above, various defects have occurred.
However, in this embodiment, since the stopper 140 is provided on the side of the condensing element 20 as described above, it is assumed that the focus servo pull-in fails and the actuator 100 runs out of control. Even if it jumps out in the (+) direction, the projection 141 of the stopper 140 comes into contact with the optical recording medium 10 first, so that the condensing element 20 and the optical recording medium 10 do not directly collide. The probability of the focus servo going out of control is most likely to occur during the initial pull-in described above, and it will not run out of play unless it is subjected to a very strong external shock during steady operation.

Here, in the optical recording / reproducing apparatus of this embodiment, when performing the above-mentioned focus servo pull-in operation, first, the carriage 5 is moved to the position of the innermost circumference 11 of the optical recording medium 10 as an initialization operation. Are controlled by a control circuit (not shown). Therefore, the focus servo pull-in operation is always performed near the innermost circumference 11, and the stopper 140
The protruding portion 141 of the
1 is on the right side of the distance D or more in FIG. Therefore, the protrusion 141 abuts on the optical recording medium on the inner circumference side of the innermost circumference 11. Unlike the information recording area 13, no valid information is recorded in this area, and therefore, even if the surface of the optical recording medium 10 is damaged by the contact of the protruding portion 141, the recording / reproducing quality of the information is not improved. It has nothing to do with it.

Further, as described with reference to FIGS. 1 and 2, the suspension 1 forming the movable support mechanism of the actuator 100.
02 is one end 102a on the fixed side to the other end 102 on the movable side.
Since the direction extending to b coincides with the rotation direction R of the optical recording medium 10 (that is, the tangential direction of the track groove 14), the stopper 140 comes into contact with the optical recording medium 10 to cause a frictional force (or torque). Suspension 10
Never buckle 2.

Therefore, there is no possibility that the condensing element 20 and the optical recording medium 10 collide in the information recording area 13, and the working distance (WD) of the condensing element 20 may be shortened to the limit. According to the present invention, this working distance (W
D) can be shortened to about 0.5 mm. Further, it is possible to prevent the situation where the suspension 102 buckles and the actuator 100 fails.

In addition, in the embodiment described above, as a control method of the optical recording / reproducing apparatus, the carriage 5 is moved to the innermost circumference 11 of the optical recording medium 10 by the control sequence of the optical recording / reproducing apparatus, and the focus servo is initialized. It is assumed that the pull-in operation will be performed. This is an optical recording medium 1
This is because 0 is generally smaller in surface wobbling on the inner peripheral side, so that pulling in of the focus servo is relatively easy. Conversely, when the surface wobbling of the optical recording medium 10 is not so large, it is sufficiently possible to pull in the focus servo at the outermost circumference 12 of the recording area 13. However, in that case, the protruding portion 141 of the stopper 140 needs to be provided on the opposite side (left side in FIG. 4) with respect to the light collecting element 20, and by doing so, the outer peripheral side of the recording area 13 (the optical recording medium 10).
Of the optical recording medium 1 with the protruding portion 141
0 comes into contact.

(Embodiment 2) Embodiment 2 is another embodiment of the optical pickup according to the present invention, and is shown in a perspective view in FIG.

In this embodiment, the operating principles of the actuator 200 and the optical head (not shown) are the same as those in the above-described first embodiment, but the method of forming the stopper, that is, the protrusion 241 is different. That is, in FIG. 5, the protrusion 241 is formed on one side of the light-collecting element 20 and is formed integrally with the holder 201. In this case, the holder 201 is preferably made of a resin that has excellent mechanical strength and abrasion resistance.
In this example, practical use could be achieved by using a resin in which fluorine is specifically mixed.

The operation and effect of this embodiment are the same as those of the above-described first embodiment, and will be omitted.

In addition, in addition, in the second embodiment, it is assumed that the initial pull-in operation of the focus servo is performed at the innermost position of the optical recording medium. However, as described supplementarily in the first embodiment, it is possible to pull in the focus servo at the outermost position of the recording area. However, in that case, the protrusion 241 needs to be provided on the opposite side (left side in FIG. 5) of the light-collecting element 20.

(Embodiment 3) In the above Embodiments 1 and 2, the stopper protrusions 141 and 24 are provided on the optical pickup side.
1 is provided to prevent the light-collecting element 20 from directly colliding with the optical recording medium 10. In the third embodiment, instead, the same action and effect are obtained by devising the shape of the cartridge that houses the optical recording medium 10.

In FIG. 6 and FIG. 7, 30 is an optical recording medium 1.
It is a cartridge for storing 0 inside. The cartridge 30 is provided with an opening window 31 that is slightly larger inward than the information recording area 13 of the optical recording medium 10 on the inner peripheral side and the outer peripheral side. The opening window 31 is shielded when the optical recording / reproducing apparatus is loaded. A shutter (not shown) is opened so that the internal optical recording medium 10 can be seen through the opening window 31. On the inner peripheral side and / or the outer peripheral side of the opening window 31, the contact surface 32 is integrally formed with the cartridge 30.
a, 32b are formed, and the contact surfaces 32a, 32a,
b is located closer to the light converging element 20 than the surface 16 of the optical recording medium 10 by steps SCa (FIG. 7) and SCb (FIG. 6). The steps SCa and SCb are the stopper surfaces 3 of the holder 301 of the actuator 300, respectively.
Height S from 01a and 301b to the upper surface of the condensing element 20
It is set larger than La (FIG. 7) and SLb (FIG. 6).

In this embodiment, the optical recording / reproducing apparatus carries the carriage 5 during the initial pull-in operation of the focus servo.
Is transferred to either the innermost circumference 11 or the outermost circumference 12 of the information recording area 13. If the focus pull-in fails and the actuator 300 runs out of control,
The stopper surface 301a or 301b of the holder 301 comes into contact with the hitting surface 32a or 32b of the cartridge 30 to restrict the stroke of the focusing operation. However, due to the above relationship of SCa> SLa, SCb> SLb, the condensing element 20 is apart from the surface 16 of the optical recording medium 10 even in this state, so there is no possibility of direct collision.

If the diameter of the light collecting element 20 is sufficiently large, the outer peripheral portion or the flange portion of the light collecting element 20 may be brought into contact with the contact surface 32a or 32b of the cartridge 30. . In addition, the cartridge 30
Depending on the size and shape of the condenser element 20 and the holder 301,
Instead of forming special surfaces as the contact surfaces 32a and 32b, it is possible to use the outer surface 33 of the cartridge 30 and bring the holder 301 into contact with this surface. All of these are applications of the present invention and are within the scope of technical ideas.

[0026]

As described above, according to the present invention, it is possible to prevent the light-collecting element (objective lens) from directly colliding with the optical recording medium, and to indirectly make contact with the area other than the information recording area. Therefore, the light condensing element and the optical recording medium are not damaged so as to hinder information recording / reproduction. It is also possible to shorten the working distance between the light collecting element and the optical recording medium, that is, the working distance (WD) to the utmost limit.
Further, it is possible to prevent the breakage of the actuator without buckling and deforming the most delicate suspension as a constituent element of the actuator.

Therefore, the reliability of the optical recording / reproducing apparatus can be greatly improved, and further contributes to the thinning and downsizing of the apparatus, which is of great technical significance. In addition, it is not necessary to add a special expensive component for these improvements.

[Brief description of drawings]

FIG. 1 is a perspective view showing the vicinity of an optical pickup of an optical recording / reproducing apparatus in Embodiment 1 of the present invention.

FIG. 2 is a plan view of the optical pickup according to the first embodiment.

FIG. 3 is a side sectional view of the optical pickup according to the first embodiment and is a view corresponding to the section AA of FIG.

FIG. 4 is a front cross-sectional view of the optical pickup according to the first embodiment and is a view corresponding to the cross section BB of FIG. 2.

FIG. 5 is a perspective view showing an optical pickup according to a second embodiment of the invention.

FIG. 6 is a front sectional view showing an optical pickup according to a third embodiment of the invention.

FIG. 7 is a front sectional view showing an optical pickup according to a third embodiment of the invention.

FIG. 8 is an explanatory diagram showing the occurrence of defects according to a conventional technique.

[Explanation of symbols]

 5 Carriage 10 Optical recording medium 11 Innermost circumference 12 Outermost circumference 13 Information recording area 14 Track groove 15 Recording surface 16 Surface 20 Condensing element 25 Wear powder 30 Cartridge 32a, 32b Degree surface 100, 200, 300, 400 Actuator 101, 201, 301, 401 Holder 102, 202, 402 Suspension 150, 250, 350, 450 Optical pickup 140 Stopper 141, 241 Projection 110 Optical head 301a, 301b Stopper surface

Claims (7)

[Claims] 1. A condensing element for forming a spot on an optical recording medium, an actuator for controlling the position of the condensing element, an actuator mounted on the actuator and driven integrally with the condensing element, An optical pickup comprising: a stopper that is attached so as to protrude toward the optical recording medium side from the condensing element at a position closer to the inner circumference or outer circumference of the optical recording medium with respect to the optical axis. 2. The optical pickup according to claim 1, wherein the stopper is made of resin, rubber or elastomer softer than the surface material of the optical recording medium, or felt or non-woven fabric. 3. The optical pickup according to claim 1, wherein the stopper is formed integrally with a holder that holds the light-collecting element. 4. The optical pickup according to claim 1,
An optical recording / reproducing apparatus characterized by being configured to perform a focus servo pull-in operation of an actuator near an innermost circumference or an outermost circumference of an information recording area of an optical recording medium. 5. A light condensing element for forming a spot on an optical recording medium, an actuator for controlling the position of the light condensing element, and a stopper mounted on the actuator and integrally driven with the light condensing element. An optical pickup characterized in that a suspension forming a movable support mechanism of the actuator is arranged such that a pulling direction thereof substantially coincides with a rotation direction of the optical recording medium, that is, a track groove direction. 6. A cartridge for accommodating an optical recording medium, wherein a contact surface is formed near the innermost periphery and / or the outermost periphery of the optical recording medium, and the contact surface is used for focusing operation of an optical pickup. A cartridge characterized by being a surface that regulates stroke. 7. An apparatus for recording / reproducing information on / from the optical recording medium housed in the cartridge according to claim 6.
An optical recording / reproducing apparatus configured to perform a focus servo pull-in operation of an actuator near an innermost circumference or an outermost circumference of an information recording area of the optical recording medium.