KR20030050888A - Optical pick-up module and fabrication method for thereof - Google Patents

Abstract

PURPOSE: An optical pickup module and a method for manufacturing the same are provided to reduce the thickness of an optical pickup device by using an optical pickup module formed of a single part. CONSTITUTION: An objective lens(210) condenses a beam to an optical disk. An optical path guide substrate(220) includes a body tube(227) provided for combing the objective lens, an upper substrate(221) having a reflective area(224) at an inside surface, and a lower substrate(222) having reflective areas(223,225) at an inside surface. A light emitting unit(230) is fixed inside the optical path guide substrate and emits a beam for data recording/playback to the optical disk. A light receiving unit is fixed inside the optical guide substrate and receives the beam reflected from the optical disk.

Description

Optical pick-up module and fabrication method for optical}

The present invention relates to an optical pickup apparatus capable of recording and reproducing data for an optical disc recording medium.

Today, the storage medium is changing from tape to disk due to digitalization, large capacity, and the like, and the storage capacity of the disk is increased by increasing the recording density for storing data on the disk. Therefore, in compact discs (CD), in which a laser diode used as a light source has a wavelength of 780 nm, discs suitable for wavelengths of 650 nm and 405 nm have recently been developed for the purpose of large capacity. Accordingly, various optical pickup apparatuses for recording and reproducing information on the disc have been developed so that they can be simultaneously applied to discs having different storage densities in terms of backward compatibility.

1 is a view schematically showing an optical system constituting such a conventional optical pickup device.

Referring to FIG. 1, the optical system constituting the conventional optical pickup apparatus includes a light emitting / receiving unit 11 for emitting and receiving a beam; A hologram element 12 for adjusting a traveling direction of the beam emitted from the light emitting / receiving portion 11 and the beam incident on the light emitting / receiving portion 11; A collimator lens 13 which makes the beam emitted from the light emitting / receiving part 11 into parallel light; And an objective lens 14 for condensing parallel light beams transmitted through the collimator lens 13 on the optical disk 15.

Here, the hologram element 12 transmits the beam emitted from the light emitting unit 11 to the collimator lens 13, and the beam reflected from the optical disk 15 is transmitted to the light receiving unit 11. Adjust the direction of travel of each beam so that This can be implemented using the polarization characteristics of the beam.

In addition, the optical system exemplified in FIG. 1 shows a basic configuration, and according to characteristics of the optical system required, numerical aperture adjusting means, phase compensating means, beam splitter, etc. may be further added. Branch optical means (eg, prisms, mirrors, etc.) may be needed further.

Meanwhile, various new disc recording devices such as DVD, MO, MD, etc. have recently emerged, and these recording devices are becoming faster and higher in density, and the recorded PIT and track pitch of the disc surface are also getting smaller. It is losing. Accordingly, there is a need for an optical pickup device that directly reads and writes data directly on the disk surface, and responds more sensitively to the disk surface.

In addition, such disk recording apparatuses are being developed with the trend of making the thickness thinner, and application to mobile communication terminals such as mobile phones and PDAs is under consideration. Accordingly, it is necessary to develop an optical pickup device having a thickness of 5 mm or less. However, in the conventional optical pickup device, there are limitations in that many constraints are caused to reduce the thickness due to the structures constituting the optical system.

The present invention was created in view of the above conditions, and in forming an optical system, an optical system is formed by using an optical path guide substrate having a reflective surface formed on an upper / lower substrate without using an optical component in the form of a block. Accordingly, an object of the present invention is to provide an optical pickup module capable of satisfying an ultra-thin thickness of 5 mm or less and a method of manufacturing the optical pickup module.

In addition, the present invention has been made in view of the above conditions, there is another object to provide an optical pickup device that can be manufactured in an ultra-thin thickness of 5mm or less by using an optical pickup module formed of a single component.

1 is a view schematically showing an optical system constituting a conventional optical pickup device.

2 conceptually illustrates a structure of an optical pickup module according to the present invention;

3 to 5 are views showing various embodiments of the optical pickup module according to the present invention.

6 is a view conceptually showing a state in which the FPCB is coupled to the optical pickup module according to the present invention.

7 is a view showing an example of a configuration of a finite optical system as an embodiment of the optical pickup module according to the present invention.

<Explanation of symbols for the main parts of the drawings>

11 ... light emitting / receiving part 12 ... hologram element

13 ... collimator lens 14 ... objective lens

15 ... optical disc 210 ... objective lens

220 ... light path guide board 221 ... top board

222 ... Lower substrate 223 ... Parabolic reflecting surface

224 ... light split hologram elements225, 511 ... reflective surface

226 ... support 227 ... barrel

230 ... light emitter 240 ... light receiver

250 ... Monitoring Receiver260 ... spacer

270 ... Connection terminal 410 ... Parabolic hologram element

510 ... Diffraction element mirror

In order to achieve the above object, the optical pickup module according to the present invention,

An objective lens for condensing a beam on the optical disk;

A light path guide substrate having a barrel provided to allow the objective lens to be coupled thereto, and having an upper substrate having a reflective region formed therein and a lower substrate having a reflective region formed therein so that a beam may be incident on the objective lens;

A light emitting unit which is fixed inside the optical path guide substrate and emits a beam for data recording / reproducing on the optical disk; And

A light receiving unit fixed inside the optical path guide substrate and configured to receive a beam reflected from the optical disk; Its features are to include.

Here, the upper substrate and the lower substrate of the optical path guide substrate is characterized in that it is formed of silicon.

In addition, in forming the optical path guide substrate, there is a feature in that a spacer is provided to maintain a gap between the upper substrate and the lower substrate.

In addition, the spacer is the same as the material of the upper substrate or the lower substrate, it is characterized in that it is formed collectively during the processing of the upper substrate and / or lower substrate.

In addition, the spacer is characterized in that it is formed of an insulating material to prevent heat transfer between the upper substrate and the lower substrate.

In addition, the lower substrate is characterized in that the reflective surface is formed so that the beam emitted from the light emitting portion can be incident to the objective lens.

In addition, the reflective surface formed on the lower substrate is characterized in that it has a radius of curvature of a parabolic surface.

In addition, the lower substrate is characterized in that the hologram element (HOE) is formed so that the beam emitted from the light emitting portion can be incident to the objective lens.

In addition, the hologram element is characterized in that the parabolic hologram element (parabolic HOE).

In addition, the lower substrate is characterized in that a diffraction element mirror (DOE mirror) is formed so that the beam emitted from the light emitting portion can be incident to the objective lens.

In addition, the light path guide substrate inner surface is characterized in that the support for mounting the light emitting portion, the direction of the beam emitted from the light emitting portion is provided.

In addition, the light path guide substrate inner surface, characterized in that the light splitting hologram element for adjusting the traveling direction of the beam emitted from the light emitting portion and the beam incident to the light receiving portion is provided.

In addition, the light splitting hologram device is characterized in that the reflection direction of the incident beam is selected according to the polarization characteristic of the incident beam.

In addition, the light splitting hologram element is the same as the material of the upper substrate or the lower substrate, it is characterized in that it is formed collectively during the processing of the upper substrate or lower substrate.

The optical path guide substrate may further include a monitoring light receiver FMPD for inspecting the sensitivity of the beam emitted from the light emitter.

The optical path guide substrate may further include an electrical connection terminal for controlling the operation of the light emitting part and the light receiving part and for transmitting a detected signal.

In addition, the manufacturing method of the optical pickup module according to the present invention in order to achieve the above object,

Forming a barrel through which the objective lens can be coupled to the upper substrate, and a reflective surface capable of reflecting a beam incident from the light emitting unit;

Fixing an objective lens to a barrel formed on the upper substrate;

Forming a reflection surface on the lower substrate to allow the beam to enter the objective lens, and forming a support for mounting the light emitting portion and the light receiving portion;

Forming an electrical connection terminal on the lower substrate to an external terminal for controlling the light emitting unit and the light receiving unit and transmitting a detected signal;

Fixing a light emitting unit and a light receiving unit to a support formed on the lower substrate; And

Combining and adjusting a distance and a mutual position of the upper substrate and the lower substrate so that the beam emitted from the light emitter may be focused through the objective lens; Its features are to include.

Here, the reflective surface of the upper substrate and / or lower substrate is characterized in that it is formed through the etching process.

The reflective surface formed on the upper substrate and / or the lower substrate may include a light splitting hologram element for adjusting a traveling direction of a beam emitted from the light emitting unit and a traveling direction of a beam incident to the light receiving unit. It has its features.

In addition, the reflective surface provided on the lower substrate so that the beam is incident to the objective lens is characterized in that it is formed to have a radius of curvature of the parabolic surface (parabolic surface).

In addition, the reflective surface provided on the lower substrate so that the beam is incident to the objective lens is characterized in that the hologram element (HOE) is formed.

In addition, the hologram element is characterized in that the parabolic hologram element (parabolic HOE).

In addition, the reflective surface provided on the lower substrate so that the beam is incident to the objective lens is characterized in that it is formed of a diffraction element mirror (DOE mirror).

In addition, the upper substrate and / or lower substrate is characterized in that it is formed of silicon.

In addition, the optical pickup device according to the present invention in order to achieve the above object,

The optical pickup module;

A control unit controlling an operation of the optical pickup module; And

A printed circuit board (PCB) connecting the optical pickup module and the control unit; Its features are to include.

Here, the printed circuit board is characterized in that the flexible printed circuit board (FPCB).

According to the present invention, in forming the optical system, the optical system is formed using an optical path guide substrate having a reflective surface formed on the upper / lower substrates without using the optical component in the form of a block. There is an advantage that can be satisfied.

In addition, the present invention has an advantage of manufacturing an ultra-thin optical pickup device having a thickness of 5 mm or less by using an optical pickup module formed of a single component.

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

2 is a view conceptually showing the structure of an optical pickup module according to the present invention.

Referring to Figure 2, the optical pickup module according to the present invention includes an objective lens for condensing a beam on an optical disk; A barrel 227 is provided to allow the objective lens 210 to be coupled, and an upper substrate 221 having a reflective area 224 formed therein and a reflection on an inner surface so that a beam may be incident on the objective lens 210. A light path guide substrate 220 having a lower substrate 222 on which regions 223 and 225 are formed; A light emitting unit 230 fixed to the inside of the optical path guide substrate 220 and configured to emit a beam for data recording / reproducing on the optical disc; And a light receiving unit 240 fixed inside the light path guide substrate 220 and capable of receiving a beam reflected from the optical disk.

Here, the upper substrate 221 and the lower substrate 222 of the optical path guide substrate 220 may be implemented using a substrate having a high reflectance such as silicon. In addition, since the upper substrate 221 and the lower substrate 222 of the optical path guide substrate 220 is a material that can be produced by an etching process, it does not need to be limited to silicon. In addition, the upper substrate 221 and the lower substrate 222 may be a material that can be manufactured through the MEMS process. In forming the optical path guide substrate 220, a spacer 260 is further provided between the upper substrate 221 and the lower substrate 222 so as to maintain an appropriate interval.

At this time, the spacer 260 may use the same material as the material of the upper substrate 221 or the lower substrate 222, in this case, during the processing of the upper substrate 221 and / or lower substrate 222. It can also form collectively. In addition, the spacer 260 may be formed of an insulating material to prevent heat transfer between the upper substrate 221 and the lower substrate 222.

Referring to FIG. 2, when the light emitting unit 230, for example, a laser diode, is seated on the support 226 provided on the lower substrate 222, heat generated from the light emitting unit 230 is the objective. There is a fear that the lens 210 will be delivered. As such, when heat generated in the light emitter 230 is transferred to the objective lens 210, deterioration occurs in data recording and reproduction. Accordingly, a heat dissipation plate is usually attached to the lower substrate 222, thereby preventing heat transfer to the objective lens 210.

That is, according to the requirements of the system, when it is necessary to actively prevent heat transfer, the spacer 260 may block heat transfer using a separate insulating material, and serve as a heat sink and the lower substrate 222 and the upper substrate. When the heat transfer can be prevented at intervals between the 221, the spacer 260 and the upper substrate 221 or the lower substrate 222 may be collectively processed using the same material.

Meanwhile, referring to FIG. 2, the light beam emitted from the light emitter 230 passes through the reflective surface 225 formed on the lower substrate 222 and the light splitting hologram element 224 formed on the upper substrate 221. Is incident on. The beam incident on the light splitting hologram element 224 is incident on the objective lens 210 through the parabolic reflecting surface 223 formed on the lower substrate 222. In this case, the parabolic surface 223 converts the incident beam into parallel rays due to its characteristics, and thus it is possible to construct an infinite optical system without using a collimator lens separately.

The light splitting hologram element 224 allows the beam emitted from the light emitter 230, for example, the laser diode LD, to enter the parabolic reflecting surface 223, and the beam reflected from the optical disk is For example, the light receiving unit 240 may be incident on the photodiode PD. This is because the light splitting hologram element 224 is designed in consideration of the polarization characteristic of the beam incident on the light splitting hologram element 224, so that the traveling direction of the reflected beam can be adjusted according to the polarization direction of the incident beam. do.

The light splitting hologram element 224 may be formed collectively at the time of forming the upper substrate 221, or may be separately manufactured and then assembled and attached to an appropriate position provided on the upper substrate 221.

In addition, a front monitoring photo diode (FMPD) 250 is separately provided on the lower substrate 222, and receives a predetermined amount of beams reflected from the light splitting hologram element 224 to thereby emit the light 230. It is possible to detect the characteristics of the beam to be emitted from. The monitoring light receiver 250 is used as an input signal for controlling the output of the light emitter 230 of the laser during recording / reproducing.

The light path guide substrate 220 controls an operation of the light emitter 230, the light receiver 240, and the monitoring light receiver 250, and electrically connects to an external device (eg, a controller) for transmitting the detected signal. The connection terminal 270 is further provided.

3 to 5 are diagrams illustrating an embodiment of an optical pickup module according to the present invention. A modified embodiment of the optical pickup module according to the present invention will be briefly described with reference to the drawings.

First, referring to FIG. 3, a change occurs in the direction of a beam emitted from the light emitter 230 when compared with FIG. 2. In this case, the support 226 is provided flat on the lower substrate 222, the reflecting surface 225 is formed to be inclined to show the structure in which the beam emitted to the light splitting hologram element 224 is incident. In this way, according to the direction of the beam, by properly designing the positions of the reflective surfaces 225, 224, 223, the beam emitted from the light emitting unit 230 can be focused through the objective lens 210. It becomes possible.

4 illustrates a case where a parabolic hologram element 410 having the same function is used on the lower substrate 222 instead of the parabolic reflecting surface 223. That is, by using the parabolic hologram element 410, the optical system capable of condensing the beam incident from the light splitting hologram element 224 through the objective lens 210. In addition, the shape of the lower substrate 222 may be formed in a plane, and the gap between the upper substrate 221 and the lower substrate 222 may be adjusted by the spacer 260.

In addition, FIG. 5 illustrates a case in which a DOE mirror is formed on the lower substrate 222 instead of the parabolic reflecting surface 223, and the light splitting hologram element 224 is implemented on the lower substrate 222. to be. In the example shown in FIG. 5, the beam emitted from the light emitter 230 is emitted in a direction opposite to the direction of the objective lens 210. Accordingly, a plurality of reflective surfaces 511, 225, 224, 225, and 510 are used to adjust the optical path so that the beam emitted from the light emitter 230 may be incident on the objective lens 210. These should be formed in proper position sequentially.

That is, as shown in FIGS. 2 to 5, the optical path guide substrate 220 may be implemented in various ways in accordance with thermal transfer problems, processing and assembly ease, and optical system requirements.

Next, a method of manufacturing the optical pickup module having such various configurations will be briefly described with reference to FIG. 2.

First, the barrel 227 to which the objective lens 210 may be coupled, and the light splitting hologram element 224 to reflect the beam incident from the light emitting unit 230 are formed on the upper substrate 221. . The objective lens 210 is fixed to the barrel 227 formed on the upper substrate 221. In this case, the objective lens 210 may be composed of one aspherical lens, or may be formed of two or more aspherical lens assemblies.

Meanwhile, a reflective surface 225 and a parabolic reflective surface 223 are formed on the lower substrate 222 so that a beam may be incident on the objective lens 210, and the light emitting unit 230 and the light receiving unit 240 may be formed. A support 226 that can be seated is formed. In addition, the lower substrate 222 controls the light emitting unit 230 and the light receiving unit 240, and forms an electrical connection terminal 270 with the outside for transmitting the detected signal. The light emitting unit 230 and the light receiving unit 240 are fixed to the support 226 formed on the lower substrate 222.

The reflective surfaces 223, 224, and 225 provided on the upper substrate 221 and the lower substrate 222 may be formed through a MEMS technique and an etching process. In the case of the simple reflective surface 225, a plane having an appropriate reflectance can be formed only by polishing the surface. The light splitting hologram device 224 may be formed through a MEMS technique and an etching process, or may be coupled to the upper substrate 221 after completing the device through a separate manufacturing process.

Accordingly, by adjusting the distance and mutual position of the upper substrate 221 and the lower substrate 222 so that the beam emitted from the light emitter 230 can be focused through the objective lens 210, by combining, It is possible to implement the optical pickup module according to the present invention.

In this case, if necessary, a spacer 260 of an insulating material may be provided between the upper substrate 221 and the lower substrate 222, and the same material may be used when the upper substrate 221 or the lower substrate 222 is processed. It can also be processed in batches.

6 is a diagram conceptually illustrating a state in which an FPCB is coupled to an optical pickup module according to the present invention.

As shown in FIG. 6, by connecting the flexible printed circuit board (FPCB) 600 to the connection terminal 270 formed in the optical pickup module described above, a control signal is applied from the controller (not shown) to the optical pickup module. And, it is possible to receive a signal detected from the light receiving unit.

When the optical pickup module is configured as described above, the optical pickup module may be implemented in a very thin form as there is no need to use a separate optical component, and the optical pickup module may be used in the form of a single component. Accordingly, by connecting the manufactured optical pickup module to the flexible circuit board (FPCB) in an automated process, it is possible to easily manufacture the ultra-thin optical pickup device.

Meanwhile, in the above description, the optical pickup module configured of the infinite optical system has been described. However, as shown in FIG. 7, the optical pickup module for the finite optical system may be configured.

That is, according to the design of the reflective surface 710 constituting the optical path guide substrate 220, the beam incident on the objective lens 720 may be configured as a finite optical system. At this time, by using a lens designed to be suitable for the finite optical system as the objective lens 720, it is possible to implement an ultra-thin optical pickup module for the finite optical system.

As described above, according to the optical pick-up module and the method of manufacturing the optical pick-up module according to the present invention, in forming an optical system, the optical path is formed on the upper and lower substrates without using a block-shaped optical component By forming the optical system using the guide substrate, there is an advantage that can satisfy the ultra-thin (width 2-3mm, length 2-3mm, height 1.3 ~ 1.5mm) of 5mm or less.

In addition, in the case of using the optical pickup module according to the present invention, there is an advantage that an ultra-thin optical pickup device having a thickness of 5 mm or less using an optical pickup module formed of a single component.

Claims (22)

An objective lens for condensing a beam on the optical disk; A light path guide substrate having a barrel provided to allow the objective lens to be coupled thereto, and having an upper substrate having a reflective region formed therein and a lower substrate having a reflective region formed therein so that a beam may be incident on the objective lens; A light emitting unit which is fixed inside the optical path guide substrate and emits a beam for data recording / reproducing on the optical disc; And A light receiving unit fixed inside the optical path guide substrate and configured to receive a beam reflected from the optical disk; Optical pickup module comprising a. The method of claim 1, In forming the optical path guide substrate, the optical pickup module, characterized in that a spacer is provided to maintain a gap between the upper substrate and the lower substrate. The method of claim 2, And the spacer is formed of an insulating material to prevent heat transfer between the upper substrate and the lower substrate. The method of claim 1, The lower substrate, the optical pickup module, characterized in that the reflective surface is formed so that the beam emitted from the light emitting portion can be incident to the objective lens. The method of claim 4, wherein The reflective surface formed on the lower substrate has a curvature radius of the parabolic surface (parabolic surface). The method of claim 1, And a hologram element (HOE) formed on the lower substrate so that the beam emitted from the light emitting part can be incident on the objective lens. The method of claim 6, The hologram device is a parabolic hologram device (parabolic HOE), characterized in that the optical pickup module. The method of claim 1, And a diffraction element mirror is formed on the lower substrate such that a beam emitted from the light emitter is incident on the objective lens. The method of claim 1, The optical pickup module on the inner surface of the optical path guide substrate, a support for mounting the light emitting portion, and for adjusting the direction of the beam emitted from the light emitting portion. The method of claim 1, And an optical splitting hologram element on the inner surface of the optical path guide substrate for adjusting a traveling direction of a beam emitted from the light emitting unit and a traveling direction of a beam incident to the light receiving unit. The method of claim 10, And the light splitting hologram element selects a reflection direction of the incident beam according to the polarization characteristic of the incident beam. The method of claim 1, And a monitoring light receiving unit (FMPD) for inspecting a sensitivity of a beam emitted from the light emitting unit in the light path guide substrate. The method of claim 1, The optical path guide substrate further comprises an electrical connection terminal for controlling the operation of the light emitting unit and the light receiving unit and transmitting an detected signal. Forming a barrel through which the objective lens can be coupled to the upper substrate, and a reflective surface capable of reflecting a beam incident from the light emitting unit; Fixing an objective lens to a barrel formed on the upper substrate; Forming a reflection surface on the lower substrate to allow the beam to enter the objective lens, and forming a support for mounting the light emitting portion and the light receiving portion; Forming an electrical connection terminal on the lower substrate to an external terminal for controlling the light emitting unit and the light receiving unit and transmitting a detected signal; Fixing a light emitting unit and a light receiving unit to a support formed on the lower substrate; And Combining and adjusting a distance and a mutual position of the upper substrate and the lower substrate so that the beam emitted from the light emitter may be focused through the objective lens; Optical pickup module manufacturing method comprising a. The method of claim 14, The reflective surface of the upper substrate and / or lower substrate is formed by an etching process. The method of claim 14, The reflective surface formed on the upper substrate and / or the lower substrate includes a light splitting hologram element for adjusting a traveling direction of a beam emitted from the light emitting unit and a traveling direction of a beam incident to the light receiving unit. Optical pickup module manufacturing method. The method of claim 14, And a reflective surface provided on the lower substrate so that the beam is incident on the objective lens, the optical pickup module manufacturing method having a curvature radius of a parabolic surface. The method of claim 14, And a reflective surface provided on the lower substrate so that the beam is incident on the objective lens. The optical pickup module manufacturing method according to claim 1, wherein the reflective surface is formed of a hologram element. The method of claim 18, The hologram device is a parabolic hologram device (parabolic HOE), characterized in that the optical pickup module manufacturing method. The method of claim 14, And a reflecting surface provided on the lower substrate so that a beam may be incident on the objective lens. An optical pickup module according to any one of claims 1 to 13; A control unit controlling an operation of the optical pickup module; And A printed circuit board (PCB) connecting the optical pickup module and the control unit; Optical pickup device comprising a. An optical pickup module manufactured by any one of claims 14 to 20; A control unit controlling an operation of the optical pickup module; And A printed circuit board (PCB) connecting the optical pickup module and the control unit; Optical pickup device comprising a.