JP2006092652A - Optical pickup apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical pickup apparatus in which the influence of dew condensation is prevented and normal operation can be performed even in an environment in which dew condensation is caused. <P>SOLUTION: This apparatus is an optical pickup apparatus 1 which is provided with s semiconductor laser 10 emitting a laser beam of blue-purple color, an optical sensor 18 detecting the laser beam reflected from an optical disk D, a plurality of optical parts (11-18) guiding the laser beam to the optical disk D from the semiconductor laser 10, while guiding reflected light from the optical disk D to the optical sensor 18, and which performs recording or reproducing of data for an optical disk. A surface crossing with a course of the laser beam of respective optical parts (11-18) is coated with titanium oxide, also the apparatus is provided with reflecting mirrors 21, 22 reflecting light being the outside more than light within an effective diameter irradiating the optical disk out of laser beams emitted from the semiconductor laser 10 twice or more and irradiating the optical parts and a LED 19 emitting light of a ultraviolet band or a near ultraviolet band and irradiating the optical parts. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical pickup device that records or reproduces data on an optical disk, and more particularly to a technique that is useful for an optical pickup device that records and reproduces data using a blue-violet laser.

  In a DVD (Digital Versatile Disc) video device, a computer disk drive device, a car navigation system, and the like, an optical pickup is built in to record and reproduce data by irradiating an optical disc with laser light.

  Since the optical pickup is equipped with multiple optical components that transmit or reflect laser light, when the equipment is suddenly moved from a low temperature environment to a high temperature environment, condensation occurs on the surface of the optical components and data Recording and playback may not be performed normally.

  2. Description of the Related Art Conventionally, a technique for coating materials having various characteristics without impairing optical functions on the surface of an optical component has been proposed (for example, Patent Document 1) and realized.

In addition, even if condensation occurs on the objective lens of the optical pickup, even if condensation occurs, the hydrophilicity is increased by photoexcitation of the photocatalyst material, and the condensation is made into a thin film, thereby improving the function of the optical pickup. A technique for preventing the interference is also proposed (for example, Patent Document 2).
Japanese Patent No. 2577670 JP 2003-207601 A

  The optical pickup includes a plurality of optical components such as a diffraction grating, a beam splitter, and a collimator lens, and the laser beam transmits or reflects the plurality of optical components to generate a predetermined action. Therefore, when dew condensation occurs on these optical components, the influence of dew condensation on the laser beam is superimposed by the number of the optical components.

  Therefore, the photocatalyst material was coated on the surface of each optical component, and the photocatalyst material was photoexcited only by normally transmitting or reflecting the laser beam used for data recording / reproduction, thereby suppressing the influence of dew condensation. It was considered that the photoexcitation of the photocatalyst material was insufficient and the function of the optical pickup was hindered.

  In addition, when the photocatalyst material is photoexcited only by normal transmission or reflection of the laser beam in this way, the laser beam has a strong directivity, so that it is photoexcited in the inner region and the outer region of the laser beam irradiation portion. The degree of light excitation is greatly different, and a boundary where the degree of photoexcitation changes in a stepwise manner is generated such that the inside of the irradiated portion is strongly photoexcited and the outside region is hardly photoexcited. Then, a problem has arisen in that a water droplet flows from the outside to the inside due to this boundary, thereby affecting the function of the optical component.

  An object of the present invention is to provide an optical pickup device capable of operating as usual while avoiding the influence of condensation even in an environment where condensation occurs.

  In order to achieve the above object, the present invention provides a laser output means for emitting laser light (for example, a blue-violet laser having a wavelength of 380 nm to 420 nm, particularly a wavelength of 405 nm), an optical sensor for detecting the laser light reflected from the optical disk, A plurality of optical components for guiding the laser light from the laser output means to the optical disc and for guiding reflected light from the optical disc to the optical sensor, and for recording or reproducing data on the optical disc. The surface intersecting the path of the laser beam is coated with a photocatalytic material (for example, titanium oxide or zinc oxide), and the laser beam emitted from the laser output means is outside the light within the effective diameter irradiated to the optical disk. It was set as the structure provided with the reflection part which reflects light and irradiates the said optical component.

  According to such a means, light outside the effective diameter of the laser light is used for photoexcitation of the photocatalytic material, so that the amount of photoexcitation can be increased accordingly. In addition, light can be guided to a portion that protrudes from the optical path of the laser light, and the portion can be excited. Therefore, the influence by dew condensation can be made smaller.

  Specifically, the reflection part includes a first reflection part disposed outside the light path within the effective diameter, and one piece that reflects the reflected light from the first reflection part toward the optical component. Or it is the structure which has several 2nd reflection part.

  In order to achieve the above object, the present invention provides laser output means for emitting laser light, an optical sensor for detecting laser light reflected from the optical disk, and guiding the laser light from the laser output means to the optical disk. A plurality of optical components that guide reflected light from the optical disk to the optical sensor, and in the optical pickup device that records or reproduces data on the optical disk, a photocatalytic material (on the surface of the optical component that intersects the path of laser light) For example, titanium oxide or zinc oxide) is coated, and an LED that emits light in the ultraviolet region or near ultraviolet region (for example, wavelength 350 to 420 nm) and irradiates the optical component is provided.

  According to such a means, the photocatalytic action of the entire optical component can be reliably generated, and the photocatalytic action of the portion protruding from the optical path of the laser light is also reliably generated, thereby sufficiently reducing the influence of dew condensation. I can do it.

  As described above, according to the present invention, a photocatalytic action can be strongly generated in the entire optical component. Moreover, the action of the photocatalyst can also be generated outside the laser light irradiated portion. And there exists an effect that the avoidance of the disorder | damage | failure by dew condensation can fully be aimed at by these.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram showing the configuration of each component assembled to an opto-base in the optical pickup according to the embodiment of the present invention.

  The optical pickup 1 of this embodiment records and reproduces data on an optical disk D for blue-violet laser. For example, a semiconductor laser (laser output means) 10 that emits a 405-nm blue-violet laser, and a laser beam. A diffraction grating 11 for making a three beam, a polarization beam splitter 12 for separating a traveling wave and a reflected wave, a collimator lens 13 for making a laser beam a parallel light, and rotating the polarization of the traveling wave and the reflected wave by 90 degrees while shifting the phase. An objective lens 16 mounted on a quarter-wave plate 14 to be driven, a rising mirror 15 that changes the light path from a horizontal direction to a vertical direction, and a lens actuator (not shown) that is finely driven in a focus direction and a tracking direction at high speed. And a detection lens 17 for giving a predetermined aberration to the reflected light, and reproduction data and the focus / tracking / tilt direction from the reflected light. An optical sensor 18 on which a plurality of detection surfaces for detecting errors are formed, an LED (light emitting diode) 19 that irradiates each optical component with light in the ultraviolet region or near ultraviolet region (wavelength 350 nm to 420 nm), and laser light There are provided a first mirror 21 and a second mirror 22 that reflect light outside the effective diameter and irradiate other optical components.

  Each of these components is mounted on an optical base (not shown) formed by die-casting, for example, zinc alloy or aluminum to constitute the optical pickup 1.

Among these optical components, the light emission portion of the semiconductor laser 10, the diffraction grating 11, the polarization beam splitter 12, the collimator lens 13, the quarter wavelength plate 14, the objective lens 16, and the detection lens 17, respectively. A titanium oxide (TiO ₂ : titanium dioxide) film is formed on the exit surface and the reflecting surface of the rising mirror 15 by coating. The coating is performed on the entire surface, at least in a range that is slightly larger than the range in which the laser beam is transmitted or reflected.

  This titanium oxide film is excited by irradiation with light in the ultraviolet region or near ultraviolet region, and becomes hydrophilic. Therefore, the condensed water droplet H shown in FIG. 4 (a) has a small contact angle θ as shown in FIG. 4 (b), and the influence on the laser beam transmitted or reflected there can be reduced.

  The LED 19 is of a type that outputs light at a wide angle without its light emitting portion being covered by a condensing lens or the like. Then, the surface of the light emitting portion of the semiconductor laser 10, the diffraction grating 11, the polarization beam splitter 12, the collimator lens 13, the quarter wavelength plate 14, the detection lens 17, and the rising mirror 15 are arranged. The LED 19 is installed at a position where no partition or the like is formed between these optical components. Therefore, ultraviolet light or near ultraviolet light is irradiated to each optical component by the light emission of the LED 19, and the titanium oxide film can be sufficiently photoexcited.

  FIG. 2 is a diagram for explaining the spot shape and effective diameter of the laser light emitted from the semiconductor laser of FIG. 1, and FIG. 3 is a perspective view of a mirror portion at the front stage of the beam splitter.

  The laser light emitted from the semiconductor laser 10 has an elliptical spot shape due to the characteristics of the semiconductor laser as shown in FIG. In general, the optical pickup does not irradiate the optical disk with all of the output laser light, and only the portion T within the central effective diameter passes through the collimator lens 13 and the objective lens 16 and passes through the optical disk. It is used for data recording and playback.

  Therefore, in the optical pickup 1 of this embodiment, as shown in FIGS. 1 and 3, light outside the effective diameter (especially, light at both ends of the long axis) is reflected by the first mirror 21 and taken out to the side of the optical path. Then, the reflected light is reflected by the second mirror 22 and guided toward another optical component (for example, the detection lens 17), and used for photoexcitation of the photocatalytic material.

  The first mirror 21 and the second mirror 22 are configured by cutting and bending a thin metal plate, for example, and are fixed to the opt base by screws or an adhesive.

  As described above, according to the optical pickup 1 of this embodiment, each optical component is coated with the photocatalyst material, and each optical component is formed by the laser light from the semiconductor laser 10 and the ultraviolet light or near-ultraviolet light from the LED 19. Since the photocatalyst material is sufficiently photoexcited, even in an environment where condensation occurs, the condensation on the plurality of optical components becomes a thin film, and the influence on the laser light is reduced, so that the optical pickup 1 is usually used. You can make it work as expected. Further, not only the laser beam transmission and reflection portions are excited, but also the surroundings thereof are excited, so that the influence of dew condensation can be sufficiently reduced by the photocatalytic action.

  In addition, since the light outside the effective diameter of the semiconductor laser 10 is reflected and guided by the first mirror 21 and the second mirror 22 to the detection lens 17 in the place where the light of the LED 19 is difficult to reach, the semiconductor laser 10 is irradiated. Can be used for photoexcitation of the photocatalytic material without waste, and the influence of dew condensation on this optical component can be reduced.

  Moreover, generation | occurrence | production of mold | fungi in an optical component or its periphery can be prevented by irradiation of the light of an ultraviolet region or a near ultraviolet region.

  The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, titanium dioxide is exemplified as a photocatalyst material whose hydrophilicity is increased by photoexcitation, but other substances having the same action, such as zinc oxide, may be used as the photocatalyst material.

  Further, the embodiment includes both a configuration in which ultraviolet light is emitted from the LED and a configuration in which light outside the effective diameter of the laser beam is reflected by the first and second mirrors 21 and 22. Of these, only one of the configurations may be included.

It is the block diagram which showed each component structure assembled | attached to the opto base in the optical pick-up of embodiment of this invention. It is a figure explaining the spot shape and effective diameter of the laser beam radiate | emitted from the semiconductor laser of FIG. It is a perspective view which shows the detail of the part of the mirror in the front | former stage of a beam splitter. It explains the action of the photocatalyst, (a) is a diagram showing a state where the photocatalyst is not working, (b) is a diagram showing a state where the photocatalyst is working.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical pick-up 10 Semiconductor laser 11 Diffraction grating 12 Beam splitter 13 Collimator lens 14 1/4 wavelength plate 15 Rising mirror 16 Objective lens 17 Detection lens 18 Optical sensor 19 LED
21 First mirror 22 Second mirror

Claims (7)

Laser output means for emitting laser light having a wavelength of 380 to 420 nm, an optical sensor for detecting laser light reflected from the optical disk, and guiding the laser light from the laser output means to the optical disk and reflecting light from the optical disk to the light In an optical pickup device comprising a plurality of optical components leading to a sensor and recording or reproducing data on an optical disc,
The surface that intersects the path of the laser beam of the optical component is coated with titanium oxide,
A reflection part that reflects the light outside the effective diameter irradiated to the optical disk out of the laser light emitted from the laser output means twice or more and irradiates the optical component;
An optical pickup device comprising: an LED that emits light in the ultraviolet region or near ultraviolet region having a wavelength of 350 to 420 nm and irradiates the optical component. A laser output means for emitting laser light; an optical sensor for detecting laser light reflected from the optical disk; In an optical pickup device comprising an optical component and recording or reproducing data on an optical disc,
The surface of the optical component that intersects the path of laser light is coated with a photocatalytic material,
An optical pickup device comprising: a reflection unit that reflects light outside the effective diameter irradiated to the optical disk out of the laser light emitted from the laser output means and irradiates the optical component .   3. The optical pickup device according to claim 2, wherein the laser output means is a semiconductor laser element that outputs a blue-violet laser having a wavelength of 380 to 420 nm.   The reflection unit includes a first reflection unit disposed outside a light path within the effective diameter, and one or a plurality of second reflection units that reflect reflected light from the first reflection unit toward the optical component. The optical pickup device according to claim 2, further comprising a reflection portion. A laser output means for emitting laser light; an optical sensor for detecting laser light reflected from the optical disc; and a plurality of optical guides for guiding the laser light from the laser output means to the optical disc and for guiding reflected light from the optical disc to the optical sensor. In an optical pickup device comprising an optical component and recording or reproducing data on an optical disc,
The surface of the optical component that intersects the path of laser light is coated with a photocatalytic material,
An optical pickup device comprising an LED that emits light in the ultraviolet region or near ultraviolet region and irradiates the optical component.   6. The optical pickup device according to claim 2, wherein the photocatalytic material is titanium oxide.   The optical pickup device according to claim 2, wherein the photocatalytic material is zinc oxide.

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