JP2007265538A - Optical information recording and reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical information recording and reproducing device which can detect a position of slim pickup and is inexpensive and high in design margin. <P>SOLUTION: The optical information recording and reproducing device comprises: an optical pickup 1 which is arranged at an arbitrary position between a recording position at innermost periphery side and a recording position at outermost periphery side of the information recording medium 22; a control circuit 10 of the optical pickup 1; and a printed wiring board 2 which connects the optical pickup 1 and the control circuit 10. An optical position sensor 3 is mounted in the optical pickup 1, and in the printed wiring board 2, a reflective slit 2a which reflects output light of the position sensor 2 is formed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a thin optical information recording / reproducing apparatus, and more particularly, to an optical information recording / reproducing apparatus that can accurately detect the driving position of an optical pickup at low cost.

  FIG. 5 shows a configuration of a conventional thin optical information recording / reproducing apparatus. This optical information recording / reproducing apparatus includes an optical pickup 1, a printed wiring board 2, a lens actuator 5, an objective lens 6, a photodetector 7, a laser driving IC 8, an upper surface side mechanical cover 9a, a spindle motor 9b, a lower surface side mechanical cover 9c, and an electric The circuit unit 10 is included.

  The information recording medium (optical disk) 22 is rotationally driven by a spindle motor 9b. The optical pickup 1 is moved to a reading (writing) position and focused by a lens actuator 5. The LD provided in the optical pickup 1 is driven by the laser drive IC 8, and the reflected light from the information recording medium 22 is detected by the photodetector 7.

  The optical pickup 1 is a so-called “slim pickup”, and the dimension from the surface of the information recording medium 3 to the bottom surface of the optical pickup (the dimension of part A in FIG. 5) is set between 5 and 8 mm.

FIG. 6 shows the configuration of the optical system inside the optical pickup 1.
The optical system of the optical pickup 1 includes a CD laser 11, a DVD laser 12, diffraction gratings 13 and 14, a prism 15, a half mirror 16, a collimator lens 17, a reflection mirror 18, a quarter wavelength plate 19, an objective lens 6, and a power monitor. 21.

The laser beam in the 780 nm band emitted from the CD laser 11 or the laser beam in the 650 nm band emitted from the DVD laser 12 is divided and transmitted into a plurality of beams by the individual diffraction gratings 13 and 14 and enters the prism 15. The prism 15 reflects the laser beam from the CD laser 11 and transmits the laser beam from the DVD laser 12 to guide it to the half mirror 16. The half mirror 16 reflects each laser beam toward the collimator lens 17 with a predetermined reflection efficiency, and guides the remaining transmitted light to the light receiving element of the optical power monitor 21. The detection result is output to the laser drive IC 8 by the power monitor 21, and the emission intensity of the CD laser 11 or DVD laser 12 is controlled.
The laser light transmitted through the collimator lens 17 and reflected by the reflection mirror 18 is converted into circularly polarized light by the quarter wavelength plate 19 and enters the objective lens 6. The minute spot condensed by the objective lens 6 is condensed on the recording surface of the information recording medium 3 to record or reproduce information.
The reflected return light on the recording surface is incident on the half mirror 16 by reversing the same path, and is incident on the photodetector 7 that performs photoelectric conversion with a predetermined transmittance according to the polarization direction. The output of the photodetector is transmitted to the electric circuit unit 10 of the information recording / reproducing apparatus via the printed wiring board 2.

  The conventional slim pickup employs a flexible substrate (FPC) based on polyimide or the like as the printed wiring board 2 on which electrical components are mounted in order to limit the allowable component arrangement.

In such a slim pickup, in order to reproduce the information recording medium and detect the recording position, the position sensor 3 is mounted on the optical pickup 1, and a reflection slit 9d for reflecting the output light is provided between the information recording medium and the optical pickup. 1 is generally affixed to the optical pickup 1 side of a mechanical cover 9a installed between the two.
Usually, the interval between the slits is formed to be a few tens of μm, and the pulse of the reflected light is detected by the internal detector of the position sensor, and the recording / reproducing position is determined from the movement amount of the optical pickup.

  The upper mechanical cover 9a and the lower mechanical cover 9c prevent the printed wiring board 2 that is an FPC from floating on the information recording medium 3 side or the opposite side.

In addition, as a prior art regarding the position detection of the optical pickup, there is an “optical pickup position detection mechanism” disclosed in Patent Document 1. However, since the position of the optical pickup is detected using magnetic force, slimming is required. It is not suitable for an optical information recording / reproducing apparatus.
JP-A-9-282684

The conventional optical information recording / reproducing apparatus using the slim pickup has two major problems.
The first problem is that the manufacturing cost of the reflective slit is high. In general, the reflection slit is generally formed by subjecting a copper material deposited on a substrate surface such as a PET material to an antireflection treatment and forming a reflection slit pattern thereon by nickel plating or the like. The reflection slit is basically an indispensable part for adding a detection function to the optical pickup, and must be attached even if it is expensive to add the detection function.
The second problem is a reduction in mechanical dimension margin. Although the gap between the optical pickup 1 and the mechanical cover 9a is designed in consideration of mass production variations, a thin information recording / reproducing apparatus such as a slim or ultra slim type leads to a reduction in design margin even with a small thickness.

  The present invention has been made in view of such problems, and an object thereof is to provide an optical information recording / reproducing apparatus that can detect the position of a slim pickup, is inexpensive, and has a high design margin.

  In order to achieve the above object, the present invention provides, as a first aspect, an optical pickup that can be disposed at an arbitrary position between a recording position on the innermost circumferential side and a recording position on the outermost circumferential side of an information recording medium, An optical information recording / reproducing apparatus having a pickup control circuit and a printed wiring board for connecting the optical pickup and the control circuit. The optical pickup has an optical position sensor, and the printed wiring board has a position It is an object of the present invention to provide an optical information recording / reproducing apparatus in which a reflection slit for reflecting the output light of a sensor is formed.

  In the first aspect of the present invention, the reflection slit is preferably formed as a part of the signal pattern of the printed wiring board. Or it is preferable that a reflective slit is formed on a printed wiring board as a pattern independent of the signal pattern of a printed wiring board. In addition to any of these, it is more preferable that a reflective coating treatment be performed on the region where the reflective slit is formed.

  In order to achieve the above object, the present invention provides, as a second aspect, an optical pickup that can be disposed at any position between the recording position on the innermost circumference side and the recording position on the outermost circumference side of the information recording medium. An optical information recording / reproducing apparatus having a control circuit for an optical pickup, and a printed wiring board for connecting the optical pickup and the control circuit, wherein the optical pickup is equipped with an optical position sensor, The present invention provides an optical information recording / reproducing apparatus characterized in that a reflective slit for reflecting the output light of the position sensor is formed on the facing cover member.

  In the second aspect of the present invention, it is preferable that an opening for allowing the output light of the position sensor to pass is formed in the printed wiring board.

  In any of the above-described configurations of the first aspect or the second aspect of the present invention, the optical pickup is a slim type in which the constituent parts are arranged within a range of 5 to 8 mm from the surface of the information recording medium. Is preferred.

  According to the present invention, an optical information recording / reproducing apparatus that can detect the position of a slim pickup, is inexpensive, and has a high design margin can be provided.

[First Embodiment]
FIG. 1 shows a configuration of an optical information recording / reproducing apparatus according to the present embodiment. This optical information recording / reproducing apparatus includes an optical pickup 1, a printed wiring board 2, a reflection slit 2a, a position sensor 3, a lens actuator 5, an objective lens 6, a photodetector 7, a laser drive IC 8, an upper mechanical cover 9a, and a spindle motor 9b. The lower mechanical cover 9c and the electric circuit unit 10 are provided.
The optical pickup 1 is a so-called “slim pickup”, and the dimension from the surface of the information recording medium 3 to the bottom surface of the optical pickup (the dimension of FIG. 1, part A) is set between 5 and 8 mm.

  As the optical system of the optical pickup 1, a known configuration (for example, shown in FIG. 6) can be applied.

  FIG. 2A shows the configuration of the printed wiring board 2. The printed wiring board 2 is a flexible printed wiring board (hereinafter referred to as FPC) in which a circuit pattern is formed on a polyimide base material by a technique such as etching. In the FPC 2, a reflection slit 2 a is formed with a slit pattern of usually about a few hundreds of μm in order to reflect the output light of the position sensor 3. As shown in FIG. 2B, the slit pattern uses the ground pattern of the optical pickup 1. Therefore, when forming the reflective slit 2aa, exactly the same construction method as that for normal FPC pattern generation can be applied.

  It is preferable that the area where the reflection slit 2a is formed is an opening of the FPC cover lay so that the output light of the position sensor 3 is directly received. Usually, the exposed portion of the pattern of the FPC 2 is subjected to a coating process such as aluminum, gold, or nickel. Therefore, a material that can set the output light of the position sensor 3 to an optimum reflectance may be selected. Therefore, it is possible to create the reflective slit 2a by the same construction method as the normal FPC creation process.

  When it is necessary to make the reflection slits 2a electrically independent, it is possible to form them with an independent pattern as shown in FIG.

  The reflection slit 2a is formed on the back surface of the FPC 2. Therefore, the position sensor 3 mounted on the optical pickup 1 is set to emit output light on the bottom surface side of the optical pickup 1. When the optical pickup 1 is moved from the inner periphery to the outer periphery of the information recording medium by the mechanism drive system, the position sensor 3 and the reflection slit 2a on the FPC 2 are always in positions facing each other as indicated by the dotted line in FIG. Install.

  The position of the FPC 2 is naturally determined by the connector 10a set in the electric circuit unit 10, but it is preferably fixed to the lower mechanical cover 9c by surface bonding in order to prevent floating and the like.

  As described above, the optical information recording / reproducing apparatus according to the present embodiment can reflect the output light of the position sensor 3 using the reflection pattern 2 a formed by diverting the ground pattern of the FPC 2. Therefore, the manufacturing cost of the reflection pattern for detecting the position of the optical pickup can be reduced, and the mechanical design margin can be increased.

[Second Embodiment]
FIG. 3 shows the configuration of an optical information recording / reproducing apparatus according to the second embodiment in which the present invention is preferably implemented. FIG. 4A shows the configuration of the printed wiring board 2. This optical information recording / reproducing apparatus has substantially the same configuration as that of the first embodiment, but an opening 2b is formed in the printed wiring board 2, and a reflective slit 9e is installed in the lower mechanical cover 9c. The point is different.

  By providing the opening 2b, the output light from the position sensor 3 reaches the reflection slit 9e without being blocked by the printed wiring board 2 even when the printed wiring board 2 is bent as shown in FIG. 4B.

  Since the thickness of the reflective slit 9e is substantially the same as that of the FPC 2, it is possible to avoid a margin reduction in mechanical design.

  Since other aspects are the same as those in the first embodiment, a duplicate description is omitted.

It is a figure which shows the structure of the optical information recording / reproducing apparatus concerning 1st Embodiment which implemented this invention suitably. It is a figure which shows the shape of the flexible printed circuit board applied to the optical pick-up of the optical information recording / reproducing apparatus concerning 1st Embodiment. It is a figure which shows the structure of the optical information recording / reproducing apparatus concerning 2nd Embodiment which implemented this invention suitably. It is a figure which shows the shape of the flexible printed circuit board applied to the optical pick-up of the optical information recording / reproducing apparatus concerning 2nd Embodiment. It is a figure which shows the structure of the conventional optical information recording / reproducing apparatus. It is a figure which shows the structure of the optical system of an optical pick-up.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical pick-up 2 Printed wiring board 2a, 9d, 9e Reflection slit 2b Opening part 3 Position sensor 5 Lens actuator 6 Objective lens 7 Optical detector 8 Laser drive IC
9a Upper mechanical cover 9b Spindle motor 9c Lower mechanical cover 10 Electric circuit section 11 CD laser 12 DVD laser 13, 14 Diffraction grating 15 Prism 16 Half mirror 17 Collimator lens 18 Reflecting mirror 19 1/4 wavelength plate 21 Power monitor 22 Information recording medium

Claims (7)

An optical pickup that can be arranged at an arbitrary position between the recording position on the innermost circumference side and the recording position on the outermost circumference side of the information recording medium;
A control circuit for the optical pickup;
An optical information recording / reproducing apparatus having a printed wiring board for connecting the optical pickup and the control circuit,
The optical pickup is equipped with an optical position sensor,
An optical information recording / reproducing apparatus, wherein a reflection slit for reflecting the output light of the position sensor is formed on the printed wiring board.   2. The optical information recording / reproducing apparatus according to claim 1, wherein the reflection slit is formed as a part of a signal pattern of the printed wiring board.   2. The optical information recording / reproducing apparatus according to claim 1, wherein the reflection slit is formed on the printed wiring board as a pattern independent of a signal pattern of the printed wiring board.   4. The optical information recording / reproducing apparatus according to claim 2, wherein a reflection coating process is performed on a region where the reflection slit is formed. An optical pickup that can be arranged at an arbitrary position between the recording position on the innermost circumference side and the recording position on the outermost circumference side of the information recording medium;
A control circuit for the optical pickup;
An optical information recording / reproducing apparatus having a printed wiring board for connecting the optical pickup and the control circuit,
The optical pickup is equipped with an optical position sensor,
An optical information recording / reproducing apparatus, wherein a reflection slit for reflecting the output light of the position sensor is formed in a cover member facing the bottom surface of the optical pickup.   6. The optical information recording / reproducing apparatus according to claim 5, wherein an opening for allowing the output light of the position sensor to pass through is formed in the printed wiring board.   7. The optical information recording / reproducing apparatus according to claim 6, wherein the optical pickup is a slim type in which components are arranged in a range of 5 to 8 mm from the surface of the information recording medium.

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