KR20060105331A - Pick-up unit of a optical disc player - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pickup unit of an optical disc player, which is installed to move along a radial direction of a disc mounted on a turntable, and which reproduces or records data by condensing the light of a light source with an objective lens and irradiating it to the disc. In the pickup unit of the player, the objective lens is characterized in that the liquid lens 160, the focal length is adjusted by the surface tension that changes according to the magnitude of the voltage supplied from the control unit 170 for focusing. Therefore, the present invention uses a liquid lens that controls the surface tension according to the magnitude of the supplied voltage to adjust the focal length as an objective lens, thereby performing focusing while the liquid lens is fixed at a predetermined position. It prevents the collision between the objective lens and the disc during focusing and the servo operation error of the pickup unit even when it is misplaced by tilting or tilting.It also enables the compaction of the pickup unit by omitting the components for transporting the objective lens and their mounting space, and the electricity consumption. Has the effect of reducing

Description

Pick-up unit of optical disc player {PICK-UP UNIT OF A OPTICAL DISC PLAYER}

1 is a perspective view showing a pickup unit of a conventional optical disc player,

2 is a configuration diagram for controlling a pickup unit of a conventional optical disc player,

3A to 3C are cross-sectional views showing various conventional optical disks,

4 is a perspective view showing a pickup unit of the optical disc player according to the present invention;

5 is a configuration diagram for controlling the pickup unit of the optical disc player according to the present invention.

<Description of Symbols for Main Parts of Drawings>

110: main body 120: first coupling portion

130: second coupling portion 140: rack

150: light source 160: liquid lens

161: window 162: housing

170: control unit 171: focusing power supply unit

The present invention relates to a pickup unit of an optical disc player, and more particularly, a disc placed incorrectly with an objective lens during focusing by using a liquid lens for controlling the focal length by controlling the surface tension by the magnitude of the supplied voltage. A pickup unit of an optical disc player which prevents the collision and the servo operation error of the pickup unit.

In general, due to the increase in the amount of data to be stored, the method of storing the data changes the capacitance, electrical resistance, etc., where the data is stored, thereby storing the data in an electrical manner that stores the data and reads these changes electrically. Data is stored by changing the transmittance, reflectance, phase, polarization, etc. of the light where it is stored, and moving to an optical method that reads this change into a laser beam.

Optical discs, which are optical data recording media, are digital audio discs (DAD) for music reproduction, commonly referred to as CDs, digital video discs (DVDs), and 650 nm wavelength as HD-DVD world standards. 23.3G, 25G, 27G, which is about 5 to 6 times larger than the current DVD, on a 1.2mm thick 12cm disc with a 0.1mm recording layer using a 405nm blue violet laser, which is much denser than a DVD using a red laser. There is a Blu-ray disk that can store data such as.

The optical disk reflects the light scanned from the pick-up unit which is clamped to the turntable rotated by the spindle motor and moves along the radial direction of the optical disk so that the pickup unit reflects the reflected light or the phase of the light at the time of reflection or Read data through polarization change.

A pickup unit of a conventional optical disc player is described below with reference to the accompanying drawings.

1 is a perspective view showing a pickup unit of a conventional optical disc player, and FIG. 2 is a configuration diagram for controlling a pickup unit of a conventional optical disc player. As shown, the pickup unit 10 of the conventional optical disc player is slidable on the guide shaft 20 which is installed side by side along the radial direction of the disc (not shown) on the base plate (not shown) to be installed. Coupling portions 12 and 13 are formed on both sides of the main body 11 so as to be fitted to each other, and a rack gear-coupled with a gear (not shown) that is rotated by a pickup transport motor (not shown) on one side of the main body 11. 14 are coupled to each other, an objective lens 15 for condensing the light projected from the light source 16 is provided on the upper surface of the main body 11, and the lens transfer unit 17 in the form of a coil around the objective lens 15. ) Is provided, the lens transfer unit 17 is controlled by the control unit 18.

The conventional pickup unit 10 is moved along the guide shaft 20 by the horizontal movement of the rack (14) gear coupled with the rotating gear (not shown) by the drive of the pickup transfer motor (not shown). While moving along the radial direction of the disk (not shown) on the base plate (not shown), the light generated from the light source 16 such as a laser diode is incident on the disk (not shown) through the objective lens 15 and reflected. The data of the disc is read by the optical. At this time, when the objective lens 15 is out of focus, the controller 18 supplies a current to the lens transfer unit 17, which is a coil provided around the objective lens 15, so that the objective lens 15 is perpendicular to the disk surface. The focus of the objective lens 15 is adjusted by moving in the direction.

3A to 3C, data layers 1a, 2a, and 3a of the CD 1, DVD 2, and Blu-lay DisK 3 are respectively shown. One drawing. As shown, the thickness of each disk 1, 2, 3 is equal to 1.2 mm, but the positions where the data layers 1a, 2a, 3a are all different. For example, as in FIG. 3A, the CD 1 has a data layer 1a at a position 1.2 mm from the pick-up surface, and as in FIG. 3B, the DVD 2 has a data layer 2a at a position 0.6 mm from the pick-up surface. ), And as shown in FIG. 3C, the Blu-ray Disc 3, which is a next-generation high-density disc, has a data layer 3a at a position of 0.1 mm from the pick-up surface.

Therefore, when the discs 1, 2, 3 are normally inserted and seated on the turntable provided in the optical disc player, the objective lens 15 of the pickup unit 10 is predetermined in the state of being rotated at high speed by a normal servo operation. After focusing by a focusing operation moving up and down with a movable range of, the operations such as reproduction and recording of data recorded in a pit shape are normally performed.

However, since the objective lens 15 of the conventional optical disk player is moved in the vertical direction of the surface of the disks 1, 2, 3 by the lens transfer part 17 formed by a coil around the disks 1, 2, 3 ) Is inverted or tilted to the turntable, causing the objective lens 15 to damage the objective lens 15 by colliding with a disk that rotates at high speed when moving for focusing.

In particular, when the Blu-ray Disc 3 is seated on the tentable due to a user's mistake, the data layer 3a is compared to the data layer 3a of the other Blu-ray Disc 3 normally seated. ) Is located 1.1mm further from the plane on which it is located. At this time, when the lens transfer unit 17 moves toward the data layer 3a of the Blu-ray disc 3 to focus the objective lens 15 under the control of the controller 18, the objective lens 15 moves the data when focusing. Since the distance to the layer 3a is within 1.1 mm, the objective range 15 eventually collides with the surface of the Blu-ray disc 3, causing damage such as scratches to the Blu-ray disc 3, even the objective lens. (15) was broken or a fatal error occurred in servo operation.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to use a liquid lens for controlling the focal length by controlling the surface tension by the magnitude of the supplied voltage, thereby using the liquid lens as an objective lens. Since focusing is performed in a fixed state, even if the disc is turned upside down or tilted on the turntable, it prevents the collision between the objective lens and the disc during the focusing and the servo operation error of the pickup unit, and the components for transferring the objective lens and their mounting By omitting the space, the pickup unit can be made compact, and an optical disc player's pickup unit which reduces electric consumption is provided.

The present invention for achieving the above object is provided to move along the radial direction of the disk mounted on the turntable, and the optical disk player for reproducing or recording data by condensing the light of the light source by the objective lens and irradiating the disk In the pickup unit, the objective lens is a liquid lens in which the focal length is adjusted by the surface tension that changes according to the magnitude of the voltage supplied from the controller for focusing.

Hereinafter, with reference to the accompanying drawings, the most preferred embodiments of the present invention will be described in more detail so that those skilled in the art can be easily carried out.

4 is a perspective view illustrating a pickup unit of the optical disc player according to the present invention, and FIG. 5 is a configuration diagram for controlling the pickup unit of the optical disc player according to the present invention. As shown, the pick-up unit 100 of the optical disc player according to the present invention is a guide shaft (20) installed side by side along the radial direction of the disc (not shown) on the turntable (not shown) on both sides of the main body 110: First and second coupling parts 120 and 130 are formed to be slidably fitted in FIG. 1, and a gear (not shown) and a gear rotated by a pickup and transfer motor (not shown) on one side of the main body 110. A rack 140 to be coupled is provided, and a liquid lens 160 for condensing light projected from the light source 150 is installed on an upper surface of the main body 110, and the liquid lens 160 is controlled by the controller 170. Controlled.

The liquid lens 160 uses an electrowetting phenomenon in which the surface tension of the liquid filled inside, for example, the surface tension, which is made as small as possible by the pulling force of the molecules of water, is controlled by electricity. Fill the water inside the housing 162 where the transparent window 161 is formed to penetrate therein, and then provide a metal plate (not shown) together with the water, so that the metal plate is not in direct contact with the water so that the metal plate does not directly contact the water. Coat the insulation hundreds of times thinner than the thickness of the hair.

When a voltage is applied from the power supply unit 171 for focusing on water and a metal plate insulated from each other by an insulator, the focal length is adjusted by changing the surface shape, that is, the thickness of the water according to the change of the voltage. At this time, as the voltage supplied from the focusing power supply unit 171 increases, the focal length becomes longer by spreading the water in the liquid lens 160, and conversely, as the voltage decreases, the water in the liquid lens 160 collects, thereby increasing the focal length. Becomes shorter.

The control unit 170 passes the liquid lens 160 from the light source 150, and when the disc is out of focus from the light reflected from the disk, the control unit 170 supplies a voltage amount corresponding to each of the focal lengths of the liquid lens 160. By supplying the liquid lens 160 through the supply unit 171, the focal length of the liquid lens 160 is adjusted to perform focusing.

The operation of the pickup unit of the optical disc player having such a structure is performed as follows.

When the data of the disc is reproduced or recorded on the disc through the pickup unit 100 of the optical disc player, the light generated from the light source 150 is condensed through the liquid lens 160 to be scanned onto the disc. At this time, if the focus of the disc and the data layer of the disc is not matched by the light reflected from the disc, the controller 170 detects the voltage through which the liquid lens 160 is focused through the focusing power supply 171. Supply to the liquid lens 160. Therefore, the surface tension of the liquid lens 160 is changed according to the magnitude of the voltage supplied from the power supply for focusing 171. As a result, the thickness of the liquid lens 160 is also changed, thereby adjusting the focal length and focusing without moving the position. Is carried out.

Therefore, the liquid lens 160 may collide with the disk during focusing even if the disk, especially the Blu-ray disk, is flipped over or tilted on the turntable by focusing without shifting the position. There is no concern, thereby preventing damage to the liquid lens 160 or the disc, which is the objective lens, and to prevent the servo operation error of the pickup unit 100. In addition, by omitting components such as a coil for transferring the liquid lens 160 that serves as the objective lens for focusing, the space occupied by them may be reduced, and the pickup unit 100 may be made compact, and the liquid lens 160 may be focused for focusing. Due to the very low voltage supplied to the power, it is possible to reduce the amount of electricity used compared to the conventional.

As described above, the pickup unit of the optical disk player according to the present invention uses a liquid lens for controlling the focal length by controlling the surface tension by the magnitude of the voltage supplied to the objective lens, the liquid lens is fixed at a predetermined position Focusing prevents the collision between the objective lens and the disc during the focusing and the servo operation error of the pickup unit, even if the disc is turned upside down or tilted on the turntable, eliminating the parts and their mounting space for transferring the objective lens. As a result, the pickup unit can be made compact, and the electricity consumption is reduced.

What has been described above is only one embodiment for carrying out the pickup unit of the optical disc player according to the present invention, and the present invention is not limited to the above-described embodiment, as claimed in the following claims. Without departing from the gist of the present invention, those skilled in the art to which the present invention pertains to the technical spirit of the present invention to the extent that various changes can be made.

Claims (1)

A pickup unit of an optical disc player which is installed to move along a radial direction of a disc mounted on a turntable, and which reproduces or records data by condensing light of a light source with an objective lens and irradiating the disc, The objective lens is a liquid lens whose focal length is adjusted by a surface tension that varies according to a magnitude of a voltage supplied from a controller for focusing. The pickup unit of the optical disc player, characterized in that.

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