Protection cover of pick-up head

The invention provides a protection cover of a pick-up head provided on a traverse of an optical drive. A plate flatly is positioned on an upper surface of the traverse, and the plate has a slot, with one end of the slot fastened to a spindle motor to clamp a disc and the other end of the slot forming a staying part for the pick-up head to stay in a stand-by mode. The pick-up head is disposed in the slot and has an objective lens. When the objective lens stays in the staying part out of a periphery of a 12-cm disc, the protection cover crosses over the staying part to protect the objective lens.

FIELD OF THE INVENTION

The present invention relates to an optical drive, and particularly to a protection cover of a pick-up head to retrieve and write data on an optical disc by emitting laser light.

BACKGROUND

With the increasing data storage amount of optical discs, data signals on an optical disc are downsized and compact. Thus, elements of a pick-up head in the optical drive become tiny and delicate such that scratches or particles would affect the accuracy of data retrieving and writing of the pick-up head due to variations of beam reflection.

FIG. 1shows an example of an optical drive1in the related art. The optical drive1is a slot-in optical drive, and has a traverse3pivoted on a hollow shell2to enable rotation in a small angle. The traverse3is provided with a spindle motor4and has a transmitting motor5on its side to rotate a screw6to move a pick-up head7engaged to the screw6along the radial direction of the spindle motor4. When an optical disc8is slotted in from an opening9at the front end of the shell2, a guiding surface10of the traverse3near the opening9guides the optical disc8to a guiding rod11, and the guiding rod11guides the optical disc8to a position in the shell2to move the spindle motor4to clamp and rotate the optical disc8. Thus, the pick-up head7can move for retrieving and writing data on the optical disc8.

However, when the optical drive1is in the stand-by mode before the optical disc8is slotted in, the traverse3moves downwards and slantingly lies on the bottom of the shell2to enable the optical disc8to slot in. Meanwhile, the objective lens12on the pick-up bead7stays at a position near the end of the guiding surface10on the traverse3, which is within the periphery of a 12-cm optical disc, to enable positioning of the pick-up head7. In this way, the optical disc8slotted in the optical drive1would easily contract to the objective lens12of the pick-up head7. In some optical drives1, the guiding surface10is formed near the objective lens12, as shown in the dotted line, as protection. However, the objective lens12must be exposed to prevent the guiding surface10from contacting to the rotating optical disc. This problem is more critical in the slim type optical drive1which has a lower guiding surface10, where the optical disc8contacts the objective lens12in a higher rate to scratch and damage the objective lens.

In addition, the objective lens12stays at a position within the periphery of the optical disc8, which has a 12 cm diameter, such that the optical disc8covers the objective lens12to avoid laser beam projected from the objective lens12to leak out when the pick-up head7is activated. However, the optical disc8has a consistent reflective rate, and once the pick-up head7is deviate from the regular position due to contact, vibration or tooth leaping, the position of the pick-up head7in relation to the optical disc8is inaccurate due to the reflection of the beam. In some optical drives1, the position of the pick-up head7can be affirmed by the immediate vibration or electrical variation of tooth leaping caused by the pick-up head7hitting the spindle motor4, and the pick-up head7is then moved to a starting position within the inner predetermined radius of optical disc8. In this way, however, accuracy of the elements may be damaged and noise problem exists. Hence there is a problem to be solved in the protection structure of the pick-up head.

SUMMARY OF THE INVENTION

An objective of the present invention is to provide a protection cover of a pick-up head to move the objective lens of the pick-up head out of the periphery of the optical disc. The protection cover covers the objective lens to protect it from being damaged by contact.

A further objective of the present invention is to provide a protection cover of a pick-up head. The protection cover provide a mark of a specific reflection lightness for positioning the pick-up head.

A further objective of the present invention is to provide a protection cover of a pick-up head formed integratedly with the traverse to cover the objective lens of the pick-up head to simplify the design of the protection cover.

In order to achieve the foregoing objectives of the invention, a protection cover of a pick-up head is provided on a traverse of an optical drive. A plate flatly is positioned on an upper surface of the traverse, and the plate has a slot, with one end of the slot fastened to a spindle motor to clamp a disc and the other end of the slot forming a staying part for the pick-up head to stay in a stand-by mode. The pick-up head is disposed in the slot and has an objective lens. When the objective lens stays in the staying part out of a periphery of a 12-cm disc, the protection cover crosses over the staying part to protect the objective lens.

In an embodiment of the present invention, the protection cover can be designed for staying and zeroing positioning of the pick-up head by reflection lightness of the protection cover in ways of providing the protection cover made from metal or plastic or forming a positioning point comprising a mark, color or painting layer to change the reflection lightness. In addition, the protection cover can be a thin flat board, and can be fixed on the traverse by a screw. The plate can form a ladder-shaped extrusion to form a guiding surface at the end of the staying part and out of the periphery of the 12-cm disc along the periphery, and the extrusion is of an equal height to the protection cover. A wear protection layer can be adhered on the guiding surface and the protection cover. The protection cover can integratedly extend from the guiding surface to cover the objective lens.

DETAILED DESCRIPTION OF THE INVENTION

The techniques employed by the present invention to achieve the foregoing objectives and the effects thereof are described hereinafter by way of examples with reference to the accompanying drawings.

FIG. 2is an upper view of an optical drive20according to a first embodiment of the invention. The optical drive20is a slot-in optical drive, which comprises a shell21, a traverse22, a spindle motor23, a pick-up head24, a plurality of guiding rods25, and a protection cover26. The shell21is hollow and has a front end opening27. The traverse22is disposed in the hollow shell21and pivoted to the end near the opening27to form a pivot end28to enable rotation in a small angle. The spindle motor23is provided at the other end of the traverse22to rotate an optical disc29as shown in the dotted line. A plate30is flatly positioned on an upper surface of the traverse22, and the plate30has a long slot31along the radial direction of the spindle motor23. One end of the slot31is fastened to the spindle motor23.

The pick-up head24is provided in the slot31and can move along the slot31. The pick-up head24has an objective lens32to project a laser beam onto the optical disc29. When the optical drive20is in a stand-by mode, the other end of the slot31opposite to the spindle motor23forms a staying part33for the pick-up head24to stay in. The objective lens32of the pick-up head24stays in the staying part33out of a periphery of the 12-cm disc29. The plate30forms a ladder-shaped extrusion to form a guiding surface34at the end of the staying part33and out of the periphery of the 12-cm disc29along the periphery. The guiding rods25are disposed in the shell21above the traverse22to swing and to guide the optical disc29.

In the first embodiment, the protection cover26is a thin flat board crossing over the staying part33and fixed to the traverse22. The periphery of the protection cover26is fixed to the traverse22at the end of the slot33, and the protection cover26is of an equal height to the guiding surface34. The protection cover26crosses over and covers the objective lens32to cover the laser beam projected. The protection cover26can be fixed on the traverse22by a screw35, but is not limited to the screw35structure; that is, the protection cover26can be fixed on the traverse22by welding or adhering. The protection cover26can be made from metal or plastic, which has different beam reflective characteristics from that of the optical disc29, so the positional characteristics can be differentiated for staying and zeroing positioning of the pick-up head24. To increase the differentiation, the protection cover26may form a positioning point36at a position opposite to the objective lens32, as shown inFIG. 3. For example,FIG. 3(a) shows a mark,FIG. 3(b) shows color andFIG. 3(c) shows a coating layer to change the reflection lightness of the positioning point36.

FIG. 4shows the operation of the optical drive20of the invention. When an optical disc29′ is slotted in the opening27at the front end of the shell21, the guiding surface34guides the front end of the optical disc29′ to enter the optical drive20. The objective lens32, under covering of the protection cover26, would not contact the optical disc29′, thus preventing the objective lens32from damage. The optical disc29′ continues entering the optical drive20and is guided by the guiding rods25to a predetermined position. Then the traverse22moves upward and rotates around the pivoted end to move the spindle motor23to clamp and rotate the optical disc29′ (as shown in the dotted line inFIG. 4). The pick-up head24, originally positioned in the staying part33, performs zero positioning of the objective lens32by reflective lightness of the positioning point36of the protection cover26, and then accurately moves in a predetermined distance to the inner read/write starting position of the optical disc29. Then, the pick-up head24is activated to retrieve and write data on the optical disc29.

FIG. 5shows an optical drive according to a second embodiment of the present invention. To simplify the numerals of the elements, the second embodiment applies same numerals to the same elements in the first embodiment. The basic structure of the second embodiment is similar to that in the first embodiment. In the first embodiment, the protection cover26is a thin flat board crossing over the pick-up head24, and forms a gap from the guiding surface34, so there is fear that guidance to the slot-in of the optical disc may be affected or that scratching of the optical disc may happen. Therefore, in the second embodiment, a wear protection layer37, such as a flannelette cloth or a plastic layer, is adhered on the guiding surface34and the protection cover26, as shown by the shaded surface inFIG. 5. The wear protection layer37on the guiding surface34would cover the guiding surface34and the protection cover26continuously from the opening27toward the inner end of the protection cover26in the optical drive20. Thus, a continuous guiding surface is formed to smoothly guide the optical disc to slot in.

Thus, the protection cover of the pick-up head of the invention covers the objective lens Out of the periphery of the optical disc to protect it from being damaged by contact. Further, the protection cover provides a positioning point to change the reflection lightness for zero positioning detection of the pick-up head.

FIG. 6shows an optical drive according to a third embodiment of the present invention. To simplify the numerals of the elements, the third embodiment applies same numerals to the same elements in the first embodiment. The basic structure of the third embodiment is similar to that in the first embodiment. The difference exists in that the guiding surface38of the plate30integratedly extends toward the staying part33to form the protection cover that covers the objective lens32out of the periphery of the 12-cm optical disc29.

In the third embodiment of the present invention, the protection cover is formed by extension of the plate on the upper surface of the traverse to cover the objective lens of the pick-up head, thus reducing the manufacturing and element cost of the protection cover and simplifying the structure of the optical drive. Furthermore, the embodiments of the invention utilize slot-in optical drives as the examples to describe the invention. However, the invention is not limited to slot-in optical drives. In a tray optical drive, the pick-up head is exposed with the tray and may be contacted or deviated more easily. Thus, the protection cover of the invention can be utilized in the tray optical drive to reduce the opportunity that the pick-up head is contacted or deviated and to position the pick-up head by the positioning point when contacted or deviated

The preferred embodiments of the present invention have been disclosed in the examples. However the examples should not be construed as a limitation on the actual applicable scope of the invention, and as such, all modifications and alterations without departing from the spirits of the invention and appended claims shall remain within the protected scope and claims of the invention.