KR100358097B1 - Optical Pick-up Device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an optical pickup apparatus for accurately adjusting a position of a sense lens in front of a photodetector so that a laser beam reflected from an optical disk can be accurately received by a photodetector.

The sense lens unit of the optical pickup apparatus comprises: a sense lens for converging and transmitting the beam to receive the beam reflected from the optical disc to the light detecting means; And a guide frame extending in the optical axis direction to support the sense lens, wherein both side surfaces perpendicular to the optical axis are opened, and a predetermined side surface is opened along the optical axis direction. The sense lens is installed coaxially with the optical axis in an inner guide hole, and a guide friction part is provided along the optical axis direction on an open side along the optical axis direction, so that the sense lens is guided when the position of the sense lens is adjusted in the optical axis direction. It includes the guide frame to be able to move smoothly along the friction portion.

Description

Optical Pick-up Device

The present invention relates to an optical pickup apparatus, and more particularly, to an optical pickup apparatus for accurately positioning a position of a sense lens in front of a photodetector so that a laser beam reflected from an optical disk can be accurately received by the photodetector. .

In general, optical disc players for recording / reproducing optical discs such as a compact disc (CD) (or a recordable compact disc (CD-R)) or a digital video disc (DVD) using an optical pickup device are used. The recording / playback method is as follows.

1 is a schematic diagram showing an embodiment of a conventional optical pickup apparatus for recording / reproducing an optical disc. FIG. 2 is a perspective view of a sense lens and a driving unit of the optical pickup device of FIG. 1, and FIG. 3 is a cross-sectional view taken along line AA ′ of the sense lens and the driving unit of FIG. 2.

As shown in FIG. 1, a beam is irradiated from the laser diode 1 to reproduce the optical disc D. FIG. For example, in order to reproduce the DVD disc D, a beam of 650 nm is irradiated from the laser diode 1. The beam emitted from the laser diode 1 is divided by the diffraction grating 2 into three beams of 0th order beam and ± 1st order beam so that it can be used as a tracking servo. The beam passing through the diffraction grating 2 is transmitted or reflected by the flat plate beam splitter 3.

This beam is focused into parallel light by the converging lens 5. This parallel light is focused on the recording surface of the optical disc D via the objective lens 6.

The beam focused on the recording surface of the optical disc D is reflected and passes again through the objective lens 6 and the converging lens 5.

Then, the beam passes through the beam splitter 3, and the beam passing through the beam splitter 3 passes through the sense lens 8 and has an astigmatism optical signal having astigmatism for use as a focusing servo. Converges and enters the photodetector 9. The beam incident on the photodetector 9 is detected by the photodetector 9 and used as an image / audio signal and an electrical signal for the tracking and focusing servo.

However, in the optical pickup apparatus as described above, as illustrated in FIGS. 2 and 3, the sense lens 8 is slidable in the optical axis direction with its peripheral portion in contact with the inner surface of the guide frame 10. It is installed inside the guide frame 10.

When the optical pickup device is manufactured, the sensor lens 8 is moved and set in the optical axis direction so as to be received in a beam spot of an appropriate size on the photodetector 9.

At this time, in the conventional optical pickup apparatus as described above, only one type of optical disc such as a compact disc (CD) (or recordable compact disc (CD-R)) or a digital video disc (DVD) is recorded / reproduced. Even if the thickness of the sense lens 8 is small because the space occupied by the beam splitter is small, the overall size of the optical pickup device is not increased. When the thickness of the sense lens 8 is thick, the sense lens 8 is provided by the sense lens position adjusting means 12 so that the laser beam reflected from the optical disk forms an appropriate beam spot on the photodetector 9. When the position of the sense lens 8 is in contact with the inside of the guide frame 10, the sense lens 8 can be smoothly moved along the guide frame 10.

However, in case of recording / reproducing by using different types of optical discs, both beam splitters for reflecting or transmitting the CD laser beam and beam splitters for reflecting or transmitting the laser beam for DVD should be arranged. Since the overall size of the optical pickup device is increased due to the occupying space, the thickness of the sense lens is becoming thinner for the compactness of the optical pickup device. However, when the thickness of the sense lens becomes thin in this manner, a portion where the sense lens contacts the inner surface of the guide hole is reduced. Accordingly, the position of the sense lens by the sense lens position adjusting means is inserted so that the force applied to the sense lens is not evenly distributed so that the laser beam reflected from the optical disk can form an appropriate beam spot on the photodetector. When the sensor is adjusted, it is often the case that the sensor lens does not move smoothly due to the force imbalance at the contact points with the guide frame away from the part where the sensor lens is in contact with the sensor lens position adjusting means, and thus the axis of the sensor lens is shifted from the optical axis. There was a problem in that it is difficult to adjust the position of the sense lens when manufacturing the optical pickup device.

Accordingly, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is to accurately adjust the position of the sense lens in front of the photodetector so that the laser beam reflected from the optical disk can be accurately received by the photodetector. It is to provide an optical pickup device that allows.

1 is a schematic diagram showing an embodiment of a conventional optical pickup apparatus for recording / reproducing an optical disc;

2 is a perspective view of a sense lens and a driving unit of the optical pickup device of FIG.

3 is a cross-sectional view taken along line AA ′ of the sense lens of FIG. 2 and a driving unit thereof; FIG.

4 is a schematic view showing an embodiment of an optical pickup apparatus according to the present invention;

5 is a perspective view of a sense lens and a driving unit of the optical pickup device of FIG. And

FIG. 6 is a cross-sectional view taken along line B-B ′ of the sense lens of FIG. 5 and a driving unit thereof.

Explanation of symbols on the main parts of the drawings

110; First laser diode 112; Diffraction grating

113; Flat beam splitter 114; Round shield lens

115; Converging lens 116; Objective

119; Photodetector 120; 2nd laser diode

122; Diffraction grating 123; Cubic beam splitter

130; A sense lens unit 132; Sense Lens

134; Insertion groove 136; projection part

142; Guide frame 144; Guide hole

146; Guide friction portion 150; Sense lens position adjusting means

152; Positioning end

In order to achieve the object as described above, the present invention,

The laser beam is irradiated onto the information recording surface of the information recording medium from the laser light source of the optical pickup apparatus, and the beam reflected therefrom converges through the sense lens unit and is received by the light detecting means, thereby recording optical information on the information recording medium or the information. An optical pickup apparatus for reproducing optical information of a recording medium,

The sense lens unit,

A sense lens for converging and transmitting the beam in order to receive the beam reflected from the optical disk to the light detecting means; And

A guide frame extending in an optical axis direction to support the sense lens, and both side surfaces perpendicular to the optical axis are opened, and a predetermined side surface is opened along the optical axis direction, the guide frame being inside The sense lens is installed coaxially with the optical axis in the guide hole of the guide hole, and the guide friction portion is provided along the optical axis direction on the open side along the optical axis direction, so that the sense lens is guide friction when the position of the sense lens is adjusted in the optical axis direction. The guide frame to be moved along the part smoothly;

It provides an optical pickup device comprising a.

At the periphery of the sense lens, an adjustment end insertion groove is formed at a position corresponding to the open side along the optical axis direction of the guide frame and is coupled to the sense lens position adjusting means, and the adjustment end is inserted into the insertion groove to sense the sense. Move the lens in the optical axis direction. The insertion direction of the adjustment end is inserted in the direction from the radial direction of the sense lens toward the center of the lens.

At the periphery of the sense lens, a protrusion is formed to contact the guide friction portion at a position corresponding to the guide friction portion formed along the optical axis direction of the guide frame, and between the guide friction portion of the guide frame and the protrusion of the sense lens. The contact surface is formed in a direction orthogonal to the insertion direction of the sense lens, so that the friction force is even in the coaxial direction with the optical axis so that the sense lens can move along the optical axis direction without shaking when the sensor lens moves in the optical axis direction.

The contact surface between the guide friction portion of the guide frame and the protrusion of the sense lens is formed on the same plane as the contact surface between the end of the sense lens position adjusting means and the insertion groove of the sense lens. In addition, since the insertion direction of the sense lens position adjusting end is formed to be inserted in the direction from the radial direction of the sense lens toward the center of the lens, when the sense lens is moved in the optical axis direction by the position adjusting end, the guide frame Since friction force is generated only at the contact surface between the guide friction portion and the protrusion of the sense lens, the sense lens can be smoothly moved with minimal friction force along the guide friction portion.

Therefore, according to the optical pickup device as described above, the sense lens is installed coaxially with the optical axis in the guide hole inside the guide frame, the guide frame portion is provided with a guide friction portion along the optical axis direction on the open side along the optical axis direction As a result, when the position of the sense lens is adjusted in the optical axis direction, the friction force is evenly distributed in the coaxial direction with the optical axis so that the sense lens can be smoothly moved along the guide friction portion without a force deviation.

In addition, at the periphery of the sense lens, an adjustment end portion coupled to a sense lens position adjusting means in a direction from the radial direction of the sense lens toward the center of the lens at a position corresponding to an open side along the optical axis direction of the guide frame A groove is formed, and a protrusion is formed to contact the guide friction portion at a position corresponding to the guide friction portion formed along the optical axis direction of the guide frame, and a contact surface between the guide friction portion of the guide frame and the protrusion portion of the sense lens. Is formed in a direction orthogonal to the insertion direction of the sense lens, when the position of the optical axis direction of the sense lens can be moved smoothly without shaking along the optical axis direction.

In addition, when the contact surface between the guide friction portion of the guide frame and the protrusion of the sense lens is formed on the same straight line as the contact surface between the end of the sense lens position adjusting means and the insertion groove of the sense lens, the optical axis direction position adjustment of the sense lens The sense lens can be moved smoothly along the optical axis direction.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 4 is a schematic diagram showing an embodiment of an optical pickup apparatus according to the present invention. FIG. 5 is a perspective view of a sense lens and a driving unit of the optical pickup device of FIG. 4, and FIG. 6 is a cross-sectional view taken along line BB ′ ′ of the sense lens and the driving unit of FIG. 5.

Reference numeral 110 is a first laser diode for irradiating a first laser beam of a first wavelength. For example, when the first laser diode 110 intends to record / reproduce the DVD disc D2, the first laser diode 110 drives the first laser diode 110 to emit a 650 nm wavelength beam.

Reference numeral 120 is a second laser diode for irradiating a second laser beam of a second wavelength. The second laser diode 120 emits a 760 nm wavelength beam, for example, when recording / reproducing the CD-R disc D1.

Diffraction gratings 112 and 122 are respectively provided on front surfaces of the first and second laser diodes 110 and 120. The diffraction gratings 112 and 122 divide the respective laser beams irradiated from the first and second laser diodes 110 into three beams, i.e., zero-order beam and ± first-order beam, respectively for tracking servo.

The flat panel beam splitter 113 is disposed on the optical path of the first laser beam of 650 nm wavelength emitted from the first laser diode 110 to reflect and transmit the laser beam. On the other hand, a beam of 760 nm is coated to combat.

The cubic beam splitter 123 is disposed on the optical path of the second laser beam of 760 nm wavelength emitted from the second laser diode 120, and reflects and transmits the 760 nm wavelength beam emitted from the laser diode 120. Let's do it.

The beam reflected by the flat beam splitter 113 or the cubic beam splitter 123 passes through the coaxially mounted annular shielding lens 114, the converging lens 115, and the objective lens 116. It is focused on the recording surface of the CD-R disc D1.

Therefore, when the DVD disc D2 is to be reproduced, the 650 nm beam emitted from the first laser diode 110 is reflected by the flat beam splitter 113, and the cubic beam splitter 123 is battled. This beam is then focused on the recording surface of the DVD disc D2 via the annular shielding lens 114, the converging lens 115 and the objective lens 116.

On the other hand, when the CD-R disc D1 is to be reproduced, a 760 nm beam emitted from the first laser diode 110 is reflected by the cubic beam splitter 123, and the beam is an annular shielding lens 114, It focuses on the recording surface of the CD-R disc D1 via the converging lens 115 and the objective lens 116.

The beam is focused by parallel light by the converging lens 115, and the focused beam is focused on the disc D1 or D2 by the objective lens 116.

On the other hand, since the recording density of the CD-R disc D1 and the DVD disc D2 is different from each other, the annular shield lens 115 has a different size of the beam spot in consideration of the size of the beam spot to be focused. Used to control. The recording surface of the CD-R disc D1 is arranged farther from the optical pickup apparatus than the recording surface of the DVD disc D2. Accordingly, in the case of the DVD disc D2, a beam of 650 nm wavelength passes through the annular shielding area of the annular shielding lens 114 to form a smaller beam spot. In the case of the CD-R disc D1, a beam of 780 nm wavelength passes through the annular shielding lens 114 to form a large beam spot for the CD-R on the disc. Since the size becomes large, it can be accurately focused on the recording surface of the CD-R disc D1 disposed farther than the DVD recording surface.

After focusing on the optical disc D1 or D2, the beam passing through the converging lens 115 and the objective lens 116 passes through the cubic beam splitter 123 and the flat beam splitter 113, respectively.

Thus, the beam transmitted through the cubic beam splitter 123 and the flat plate beam splitter 123 has astigmatism for use as a focusing servo while passing through the sense lens 132 of the sense lens unit 130. It converges to the optical signal and enters the photodetector 119 with an appropriate beam spot size. This beam is received by the photodetector 119 and used as an image / audio signal and an electrical signal for tracking and focusing servos.

The sense lens unit 130 may include a sense lens 132 for converging and transmitting the beam and a guide frame 142 for supporting the sense lens 132 in order to receive the beam reflected from the optical disk to the light detecting means. It is composed.

The guide frame 142 forms a guide hole 144 extending in the optical axis direction to support the sense lens 132, and both sides perpendicular to the optical axis are opened, and a predetermined side along the optical axis direction. It is formed to be open.

The sense lens 132 is installed coaxially with the optical axis in the guide hole 144 inside the guide frame 142.

At the periphery of the sense lens 132, an adjustment end insertion groove 134 is formed at a position corresponding to the open side along the optical axis direction of the guide frame 142 and coupled with the sense lens position adjusting means 150. In addition, the adjusting end 152 is inserted into the insertion groove 134 to move the sense lens 132 in the optical axis direction. The insertion direction of the adjustment end 152 is inserted in the direction from the radial direction of the sense lens 132 toward the center of the lens.

An open side surface of the guide frame 142 is provided with a guide friction portion 146 along the optical axis direction.

At the periphery of the sense lens 132, a protrusion 136 that contacts the guide friction portion 146 is formed at a position corresponding to the guide friction portion 146 formed along the optical axis direction of the guide frame 142, The contact surface between the guide friction portion 146 of the guide frame 142 and the protrusion 136 portion of the sense lens is formed in a direction orthogonal to the insertion direction of the sense lens 132, thereby the sense lens 132. When the optical axis in the direction of the optical axis coaxial with the optical lens in the friction force evenly distributed so that the sense lens 132 can move without shaking along the optical axis direction without bias to one side.

The contact surface between the guide friction portion 146 of the guide frame 142 and the protrusion 136 of the sense lens 132 is inserted into the adjustment end 152 of the sense lens position adjusting means 150 and the sense lens 132. It is formed on the same plane as the contact surface with the groove 134. In addition, the insertion direction of the positioning end 152 is formed to be inserted in the direction toward the center of the lens in the radial direction of the sense lens 132, so that the sense lens 150 by the positioning end 152 When moving in the optical axis direction, since friction force is generated only at the contact surface between the guide friction portion 146 of the guide frame 142 and the protrusion 136 of the sense lens 132, the sense lens 132 is a guide friction portion ( 136) can be smoothly moved with a minimum friction force.

As described above, by positioning the sense lens 132 in the optical axis direction inside the guide frame 142, the light having astigmatism for the beam transmitted through the sense lens 132 to be used as a focusing servo. The signal is converged so that it can be incident on the photodetector 119 with an appropriate beam spot size. When the position of the sense lens 132 is determined, the position of the sense lens 132 is set by tightening the fixing screw 149 of the fixing unit 148 provided on the side of the guide frame 142 opened in the optical axis direction.

Therefore, according to the optical pickup device as described above, the sense lens is installed coaxially with the optical axis in the guide hole inside the guide frame, the guide frame portion is provided with a guide friction portion along the optical axis direction on the open side along the optical axis direction As a result, when the position of the sense lens is adjusted in the optical axis direction, the friction force is evenly distributed without bias, and thus the smooth movement can be performed along the guide friction portion.

In addition, at the periphery of the sense lens, an adjustment end portion coupled to the sense lens position adjusting means in a direction corresponding to the center of the lens in the radial direction of the sense lens at a position corresponding to the open side along the optical axis direction of the guide frame. A groove is formed, and a protrusion is formed to contact the guide friction portion at a position corresponding to the guide friction portion formed along the optical axis direction of the guide frame, and the contact surface between the guide friction portion of the guide frame and the protrusion of the sense lens is It is formed in a direction orthogonal to the insertion direction of the sense lens, it is possible to smoothly move the sense lens along the optical axis direction when adjusting the position of the optical axis direction of the sense lens.

In addition, when the contact surface between the guide friction portion of the guide frame and the protrusion of the sense lens is formed on the same straight line as the contact surface between the end of the sense lens position adjusting means and the insertion groove of the sense lens, the optical axis direction position adjustment of the sense lens The sense lens can be moved smoothly along the optical axis direction.

Claims (7)

The laser beam is irradiated onto the information recording surface of the information recording medium from the laser light source of the optical pickup apparatus, and the beam reflected therefrom converges through the sense lens unit and is received by the light detecting means, thereby recording optical information on the information recording medium or the information. An optical pickup apparatus for reproducing optical information of a recording medium, The sense lens unit, A sense lens for converging and transmitting the beam in order to receive the beam reflected from the optical disk to the light detecting means; And A guide frame extending in an optical axis direction to support the sense lens, and both side surfaces perpendicular to the optical axis are opened, and a predetermined side surface is opened along the optical axis direction, the guide frame being inside The sense lens is installed coaxially with the optical axis in the guide hole of the guide hole, and the guide friction portion is provided along the optical axis direction on the open side along the optical axis direction, so that the sense lens is guide friction when the position of the sense lens is adjusted in the optical axis direction. The guide frame to be moved along the part smoothly; Optical pickup device comprising a. The optical pickup apparatus of claim 1, wherein an adjustment end insertion groove is formed at a periphery of the sense lens at a position corresponding to an open side surface in the optical axis direction of the guide frame. . The method of claim 2, wherein the direction of the insertion groove is formed in a direction from the radial direction of the sense lens toward the center of the lens, thereby inserting the adjustment end into the insertion groove to move the sense lens in the optical axis direction. Optical pickup device. According to claim 1, Periphery of the sense lens, the projection portion in contact with the guide friction portion formed in a position corresponding to the guide friction portion formed along the optical axis direction of the guide frame, the guide friction portion of the guide frame and The contact surface between the protrusions of the sense lens is formed in parallel to the optical axis direction, so that when moving the optical lens direction of the sense lens to move the sense lens in the optical axis direction without shaking. The optical pickup apparatus of claim 4, wherein an adjustment end insertion groove is formed at a periphery of the sense lens at a position corresponding to an open side along the optical axis direction of the guide frame, the adjustment end insertion groove being coupled to the sense lens position adjusting means. . 6. The method of claim 5, wherein the direction of the insertion groove is formed in a direction from the radial direction of the sense lens toward the center of the lens, thereby inserting the adjustment end into the insertion groove to move the sense lens in the optical axis direction. Optical pickup device. The position adjustment according to claim 5, wherein the contact surface between the guide friction portion of the guide frame and the protrusion of the sense lens is formed on the same plane as the contact surface between the end of the sense lens position adjusting means and the insertion groove of the sense lens. When the sense lens is moved in the optical axis direction by the end, friction force is generated only at the contact surface between the guide friction portion of the guide frame and the protrusion of the sense lens, so that the sense lens can be smoothly moved with minimal friction force along the guide friction portion. Optical pickup device characterized in that.