WO2007088809A1

WO2007088809A1 - Optical head device and optical information device

Info

Publication number: WO2007088809A1
Application number: PCT/JP2007/051388
Authority: WO
Inventors: Kousei Sano; Yoshiaki Komma; Kanji Wakabayashi; Hidenori Wada; Keiichi Matsuzaki; Toshiyasu Tanaka
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 2006-01-31
Filing date: 2007-01-29
Publication date: 2007-08-09
Also published as: JP2009093684A

Abstract

An optical head device having a light source for emitting light with different wavelengths, where the device is reduced in size by reducing the size of an optical system. The optical head device has a blue semiconductor laser (203) and an LDPD module (205) for DVD that function as light sources for emitting light having different wavelengths; objective lenses (201, 202) for collecting light from the light sources on an optical information recording medium; a light detector (204) and an LDPD module (205) for DVD that function as a detection section for detecting reflection light from the optical recording medium; and an optical base (120) where the light sources, the objective lenses, and the detection section are placed. The diameter of that ray of the light from the light sources which has a short wavelength is smaller than the diameter of that ray of the light from the light sources which has a long wavelength, where the diameter is a diameter measured at a passage face of the objective lens (201 or 202) to which each ray of the light from the light sources corresponds.

Description

Specification

Optical head device, optical information device

Technical field

[0001] The present invention relates to an optical information apparatus for recording or reproducing information on an optical information recording medium represented by an optical disc, and an optical head apparatus used therefor.

Background art

[0002] Digital versatile discs (DVDs) are known as optical discs capable of recording large volumes of data because they can record digital information at a recording density approximately six times that of compact discs (CDs).

In recent years, with an increase in the amount of information recorded on an optical disc, an optical disc having a larger capacity has been demanded. In order to increase the capacity of an optical disk, it is necessary to increase the information recording density by reducing the light spot formed by the light irradiated on the optical disk. The light spot can be reduced by shortening the wavelength of the laser light from the light source and increasing the numerical aperture (NA) of the objective lens.

[0004] A DVD uses a light source having a wavelength of 660 nm and an objective lens having a numerical aperture (NA) of O.6. For example, by using a blue laser with a wavelength of 405 nm and an objective lens of NAO.85, a recording density five times that of the current DVD can be achieved.

[0005] By the way, in an optical information apparatus that realizes high-density recording / reproduction using a short-wavelength laser with a blue laser for a high-density optical disc such as a Blu-ray disc (hereinafter referred to as BD), Providing compatibility with optical discs increases the usefulness of the device and improves cost performance. In this case, it is difficult to increase the working distance as in the objective lens for DVD and CD while increasing the numerical aperture of the objective lens to 0.85. Therefore, in compatible optical information devices capable of high-density recording / reproducing, at least one objective lens used for recording / reproducing CD or DVD and an objective for high-density recording having a higher numerical aperture than this objective lens. It is desirable to provide each with a lens.

As such an optical information device, an optical head device using a BD objective lens of NAO. 85 and a DVD objective lens of NAO. 6 is known (for example, Patent Document 1, FIG. 1, (See Figure 2 etc.)

Patent Document 1: Japanese Patent Laid-Open No. 2005-327338

Disclosure of the invention

Problems to be solved by the invention

However, such a conventional optical head device has the following problems. In the configuration shown in Patent Document 1, NA is larger than that for DVD. 光 The light beam incident on the objective lens for BD has a larger diameter than the light beam incident on the objective lens for DVD. .

[0008] This brings about the following problems. In other words, BD, which performs high-density recording / reproduction, uses a high NA objective lens. For an objective lens, if NA is increased, the depth of focus becomes shallower, so higher accuracy is required for focus control.

[0009] Therefore, in the BD optical system, in addition to the high NA of the BD objective lens, the optical system on the detection side is required to have a high magnification in order to extract the focus error signal as a large change. The

[0010] However, when the diameter of the light beam on the BD side incident on the objective lens for BD is larger than that on the DVD side, the focal length of the objective lens for BD is 0.7 times the focal length of the DVD objective lens ( 0. 7 = 0.6 / 0. 85: NA ratio).

[0011] The magnification of the optical system on the detection side is determined by the focal length of the objective lens and the focal length of the optical system on the detector side that receives and processes the reflected light of the BD force. If it becomes larger, it is necessary to increase the focal length also in the optical system on the detector side, which increases the size of the entire optical system, which leads to an increase in the size of the optical head device! /

An object of the present invention is to solve the above-described conventional problems, and to provide an optical head device that can be miniaturized by miniaturizing an optical system.

Means for solving the problem

In order to achieve the above object, the first aspect of the present invention includes a plurality of light sources that emit light having different wavelengths,

In order to condense light of the plurality of light source powers onto the corresponding optical information recording media, respectively. A plurality of objective lenses,

A detector for detecting reflected light of the optical information recording medium force;

An optical base on which the plurality of light sources, the plurality of objective lenses, and the detection unit are disposed;

The diameter of the light from the plurality of light sources on the passing surface of the objective lens to which each light corresponds corresponds to an optical head device in which a short wavelength is smaller than a long wavelength.

[0014] The second aspect of the present invention is that the plurality of light sources are a first light source that emits a wavelength of λ 1 and a second light source that emits light of a wavelength λ 2 longer than the wavelength λ 1. Two light sources, wherein the plurality of objective lenses are a first objective lens that condenses the light from the first light source and a second objective lens that condenses the light from the second light source. The first objective lens has a higher numerical aperture than the second objective lens, and the diameter of the light of the first light source power on the passage surface of the first objective lens Is an optical head device according to the first aspect of the present invention, which is smaller than the diameter of the light of the second light source power on the passage surface of the second objective lens.

[0015] The third aspect of the present invention is the optical head device according to the second aspect of the present invention, wherein a lens diameter of the first objective lens is smaller than a lens diameter of the second objective lens.

[0016] Further, the fourth aspect of the present invention is a distance WD1 by which the first objective lens can move with respect to a surface of the optical information recording medium on which recording or reproduction is performed by light of the first light source; There is a relationship of WDKWD2 with the distance WD2 that the second objective lens can move with respect to the surface of the optical information recording medium on which recording or reproduction is performed by the light of the second light source. This is an optical head device of the present invention.

[0017] Further, the fifth aspect of the present invention includes a bearing for holding at least a pair of shafts for moving the optical base between an inner peripheral side and an outer peripheral side of the optical information recording medium, At least one of the bearings is disposed at each end of the optical base, and at least one of the reference line passing through the center of the second objective lens and parallel to the pair of shafts and the pair of shafts. L1 and the distance between the reference line and the other of the pair of shafts L2, there is a relationship of L1> L2,

The first light source is provided on the one side of the one shaft, The second light source is the optical head device according to the second aspect of the present invention, which is provided on the other side of the one shaft.

[0018] The sixth aspect of the present invention is the optical head device according to the fifth aspect of the present invention, wherein the reference line passes through a rotation center of a motor that rotates the optical information recording medium.

The seventh aspect of the present invention is the optical head device according to the sixth aspect of the present invention, wherein the reference line also passes through the center of the first objective lens.

[0020] Further, the eighth aspect of the present invention also sees a plane force including the pair of shafts,

The first optical system including the first light source and the first objective lens is formed to be within the width of the distance L1, and the second optical system including the second light source is the first optical system. The optical head device according to the sixth aspect of the present invention is formed so as to be within a width of the distance L2 except for the second objective lens and a rising mirror for guiding light to the second objective lens.

[0021] Further, according to a ninth aspect of the present invention, the optical base has an arc-shaped notch,

The arc of the notch is the optical head device according to the fifth aspect of the present invention, the center of which is provided so as to pass through the reference line.

[0022] Further, according to a tenth aspect of the present invention, the first objective lens has the first objective lens more than the second objective lens.

5 is an optical head device according to a fifth aspect of the present invention, which is arranged on the side closer to the light source of FIG.

[0023] The eleventh aspect of the present invention further includes a third light source that emits light having a wavelength longer than that of wavelength 2 and that is provided near the other side of the one shaft.

The optical head device according to a fifth aspect of the present invention, wherein a third optical system including the second objective lens and the third light source is formed.

[0024] The twelfth aspect of the present invention is the optical head apparatus according to the eleventh aspect of the present invention, wherein the reference line passes through a rotation center of a motor that rotates the optical information recording medium.

The thirteenth aspect of the present invention is the optical head device according to the fifth aspect of the present invention, wherein the wavelength λ 1 is 450 nm or less.

[0026] Further, the fourteenth aspect of the present invention is a beam shaping unit provided between the first light source and the first objective lens, which corrects an intensity distribution of light also having the first light source power. A fifth optical head device according to the present invention.

[0027] The fifteenth aspect of the present invention is provided between the first light source and the first objective lens. The optical head device according to the fifth aspect of the present invention includes a spherical aberration correction unit that corrects a spherical aberration generated when the optical information recording medium emitted from the first objective lens is condensed.

[0028] Further, the sixteenth aspect of the present invention includes a dimming unit that is provided between the first light source and the first objective lens and controls the transmittance of light emitted from the first light source. And an optical head device according to a fifth aspect of the present invention.

[0029] Further, the seventeenth aspect of the present invention is a beam shaping unit that receives light from the first light source and corrects an intensity distribution;

A light control unit for controlling the light transmittance;

A collimator lens that shapes incident light into substantially parallel light;

The light emitted from the first light source is disposed so as to form an optical system that passes in the order of the beam shaping unit, the light control unit, the collimator lens, and the first objective lens. This is an optical head device of the present invention.

[0030] Further, the eighteenth aspect of the present invention includes a branching unit that separates light traveling from the first light source toward the optical information recording medium and light traveling from the optical information recording medium toward the detection unit. An optical head device according to a seventeenth aspect of the present invention.

[0031] The nineteenth aspect of the present invention is the first reflection surface that reflects light from the first light source and guides the light to the first objective lens, and the first reflection surface is orthogonal to the first reflection surface. A rising mirror having a second reflecting surface that reflects light from a second light source and guides the light to the second objective lens, and the rising mirror includes the first reflecting surface and the second reflecting surface. And a cross-sectional shape that is asymmetric with respect to a bisector of an angle formed by the first reflecting surface and the second reflecting surface when viewed from a plane orthogonal to the reflecting surface of the second aspect of the present invention. This is an optical head device.

[0032] Further, in the twentieth aspect of the present invention, the rising mirror has a substantially triangular prism shape,

A side other than the side formed by the first reflective surface and the second reflective surface, and one or all of one or the other of two sides parallel to the first reflective surface and the second reflective surface, or This is the optical head device of the nineteenth aspect of the present invention, wherein the cross-sectional shape is formed by chamfering a part.

[0033] Further, the twenty-first aspect of the present invention is that the first reflecting surface and the second reflecting surface are not two sides other than the side formed by the first reflecting surface and the second reflecting surface. The optical head device according to the twentieth aspect of the present invention, wherein both sides are all chamfered, and the first reflecting surface side is chamfered more than the second reflecting surface side.

[0034] Further, the twenty-second aspect of the present invention is an optical head device according to the first aspect of the present invention;

A motor for rotating the optical information recording medium;

An optical information device comprising an electric circuit for controlling the operation of the motor and the light source based on a signal obtained from the optical head device.

The invention's effect

According to the present invention, it is possible to provide an optical head device that can be reduced in size by reducing the size of the optical system, an optical information device using the same, and the like.

Brief Description of Drawings

FIG. 1 (a) is a schematic plan view of a part of an optical information device and an optical head device according to Embodiments 1 to 4 of the present invention. (B) It is a schematic front view of a part of optical information apparatus and the optical head apparatus in Embodiments 1-4 of this invention.

FIG. 2 is a configuration diagram of an optical system of an optical head device according to Embodiments 1 to 4 of the present invention.

FIG. 3 is a schematic configuration diagram of an optical system in the vicinity of each objective lens of the optical head device according to the first embodiment of the present invention.

FIG. 4 (a) is a configuration diagram showing an overview of an LDPD module 206 for CD in Embodiments 1 to 4 of the present invention. (b) It is a figure for demonstrating the light state of the LDPD module 206 for CD radiate | emitted from the objective lens 202. FIG. (C) A diagram showing the relationship between the three spots on the optical disc and the track.

FIG. 5 (a) is an operation explanatory diagram of the filter switching element 302 according to Embodiment 2 of the present invention. (B) It is operation | movement explanatory drawing of the filter switching element 302 in Embodiment 2 of this invention. (c) Configuration diagram of a collimator lens driving element 304 according to the second embodiment of the present invention.

FIG. 6 (a) is a perspective view of a raising mirror 306 according to Embodiment 4 of the present invention. (B) It is a side view of the raising mirror 306 in Embodiment 4 of this invention. (C) is a positional relationship diagram between a rising mirror 306 and a collimator driving element 304 in Embodiment 1 of the present invention.

FIG. 7 is a diagram showing another configuration example of the rising mirror 306. FIG. 8 is a diagram showing another configuration example of the optical head device according to the first to fourth embodiments of the present invention.

FIG. 9 is a perspective view of a rising mirror 401.

FIG. 10 (a) is a diagram for explaining the operation when the raising mirror 401 is used in the first optical system. (B) It is a figure for demonstrating operation | movement when the raising mirror 401 is used in a 2nd optical system.

FIG. 11 is a schematic configuration diagram of an optical information device in a fifth embodiment of the present invention.

FIG. 12 is an external view of a personal computer (computer) using the optical information apparatus of the present invention.

FIG. 13 is an external view of an optical disk recorder (video recording apparatus) using the optical information apparatus of the present invention.

FIG. 14 is an external view of an optical disc player (video playback device) using the optical information device of the present invention.

FIG. 15 is an external view of a server using the optical information device of the present invention.

FIG. 16 is an external view of a car navigation system using the optical information device of the present invention. Explanation of symbols

A Reference line

B bisector

O Center of rotation

100 optical head device

100a Notch

110, 111 shaft

112 motor

120 optical base

121, 122, 123 bearings

124 Lead screw

125 Feed motor

126 Screw joint

200 finisher

201 Objective lens 202 Objective lens

203 Blue semiconductor laser

204 photodetector

205 LDPD module for DVD

206 LDPD module for CD

301 Beam shaper

302 Filter switching element

303 Polarizing beam splitter

304 Collimator lens drive element

305 Collimator lens 305a Honoreda

306 Raising mirror 306a First reflecting surface 306b Second reflecting surface

311, 312 ND filter

320 Wedge prism

321 Collimator lens 600 Optical information device

1000 PC

1010 Optical disc recorder

1021 Optical disc player

1030 servers

1035 network

1040 Car navigation system

BEST MODE FOR CARRYING OUT THE INVENTION

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

[0039] (Embodiment 1)

FIGS. 1A and 1B are schematic views of a part of an optical information device and an optical head device according to Embodiment 1 of the present invention.

In the schematic plan view of FIG. 1 (a), the optical head device 100 is supported in a movable state by a guide shaft composed of a pair of shafts 110 and 111 fixed to a chassis (not shown). The The motor 112 is fixed to the chassis and serves as an optical information recording medium. All optical disks (not shown here) are chucked by the turntable of the motor 112 and rotate around the rotation center O of the motor 112.

[0041] Bearings 121 and 122 (first bearing) and bearing 123 (second bearing) are provided at both ends of the optical base 120 of the optical head device 100, respectively. 110 and a bearing 123 (second bearing) are fitted into the shaft 111, respectively. The feed screw 124 is installed in parallel with the shaft 110 and is rotated by the feed motor 125. The screw coupling portion 126 is fixed to the optical base 120, and meshes with the groove of the feed screw 124 so that the rotation of the feed screw 124 is caused to rotate in the direction parallel to the extending direction of the guide shaft. Convert to move. The bearings 121 and 122 and the bearing 123 are provided at both ends of the optical base 120 in order to prevent interference with other optical elements and optical paths constituting the optical system.

In addition, the optical base 120 has a cut-out portion 100a having an arc-shaped cross section in view of the paper surface force in the drawing, and the optical head device 100 and the motor 112 approach each other to access the inner track of the optical disk. Even at this time, the optical head device 100 is prevented from colliding with the motor 112 by avoiding the motor 112 by the notch 100a.

[0043] An actuator 200 is fixed to the optical base 120 of the optical head device 100, and an objective lens 201 (first objective lens) for a high-density optical disk and a conventional one are mounted on a movable part of the actuator 200. An optical lens objective lens 202 (second objective lens) is mounted. The light emitted from the blue semiconductor laser 203 passes through a first optical system, which will be described later, and is collected by the objective lens 201 and is collected on the information surface of the high-density optical disk. The light reflected and diffracted by the high-density optical disk passes through the objective lens 201 again, enters the photodetector 204, and is converted from light to an electrical signal.

On the other hand, the light emitted from the LDPD module 205 for DVD, in which the red semiconductor laser and the photodetector are integrated, passes through the second optical system described later, and is condensed by the objective lens 202 and is a conventional disk. It is focused on the information surface of the DVD. The light reflected and diffracted by the DVD again passes through the objective lens 202, enters the photodetector of the LDPD module 205 for DVD, and is converted from light to an electrical signal.

[0045] Also, from the LDPD module 206 for CDs, in which an infrared semiconductor laser and a photodetector are integrated. The emitted light passes through a third optical system, which will be described later, and is collected by the objective lens 202 and is collected on the information surface of a CD that is a conventional disc. The light reflected and diffracted by the CD passes through the objective lens 202 again, enters the photodetector of the LDPD module 205 for DVD, and is converted from light to an electrical signal.

The objective lens 202 for DVDZCD is arranged so as to move on a reference line A parallel to the shaft 110 through the rotation center O of the disk rotation motor 112. The distance from the reference line A passing through the rotation center O to the center of the shaft 110 is Ll, and the distance from the reference line A to the shaft 111 is L2. The distance L1 is defined as the distance from the objective lens 202 to the first bearing 121, and the distance L2 is defined as the distance from the objective lens 202 to the second bearing 123.

FIG. 1 (b) is a schematic front view of the optical head device 100 and a part of the optical drive as viewed from the side. Specifically, in FIG. 1 (a), it is a view seen from the direction toward the rotation center O of the motor 112 along the reference line A.

FIG. 2 shows a configuration diagram of an optical system part of the optical head device 100. With reference to FIG. 2, the first to third optical systems described above will be described.

[0049] The first optical system includes a light incident side from the blue semiconductor laser 203 to the objective lens 201 and a light detection side from the objective lens 201 that receives the light reflected by the optical disc force to the photodetector 204. It is a blue optical system formed by each optical element.

The blue semiconductor laser 203 emits light having a first wavelength λ 1 and a wavelength of about 405 nm. Note that this wavelength varies depending on the individual laser, and a force of about 395 nm or about 450 nm may be used.

[0051] The light emitted from the blue semiconductor laser 203 is corrected by the beam shaper 301 as a beam shaping unit for the difference in the light intensity distribution direction. The light transmitted through the beam sino 301 is incident on an ND filter attached to a filter switching element 302 as a dimming unit, and the amount of transmitted light is adjusted. The light transmitted through the filter switching element 302 is reflected by the polarization beam splitter 303 as a branching unit.

The light reflected by the polarization beam splitter 303 is incident on a collimator lens 305 attached to a collimator lens driving element 304 that is a spherical aberration correction unit, and is shaped into substantially parallel light. Collimator lens drive element 304 can change the position of collimator lens 305 Then, the degree of convergence of the light after passing through the collimator lens 305 is changed, the spherical aberration generated in combination with the objective lens is changed, and the spherical convergence generated due to the thickness error of the disk substrate thickness is corrected.

The light transmitted through the collimator lens 305 is bent at a right angle by the rising mirror 306, passes through a quarter-wave plate (not shown), and then enters the objective lens 201. The light collected by the objective lens 201 is irradiated onto an optical disk (not shown) as an optical information recording medium. The optical disk here is an optical disk such as a Blu-ray Disc (BD) that is supposed to be recorded and reproduced with blue light.

The light reflected and diffracted by the optical disk is transmitted again through the objective lens 201 and the 1Z4 wavelength plate.

By passing through the 1Z4 wave plate twice, the polarization direction of light rotates 90 degrees. The light that has passed through the 1Z4 wavelength plate passes through the collimator lens 305 and passes through the polarization beam splitter 303. The light that has passed through the polarization beam splitter 303 is given astigmatism by the detection lens 307 and enters the light detector 204. The light incident on the photodetector 204 is converted into an electrical signal.

[0055] Next, the red optical system side which is the second optical system and the third optical system will be described.

The second optical system is a red optical system formed by each optical element from the LDPD module 205 to the objective lens 202 in which a red semiconductor laser and a photodetector are integrated.

The LDPD module 205 emits light having a wavelength of about 660 nm, which is the second wavelength λ 2. This wavelength varies depending on the individual laser and type, and may be about 620 nm to 690 ηm. The light emitted from the LDPD module 205 is reflected by the surface of the wedge-shaped prism 320 and converted into parallel light by the collimator lens 321. The light transmitted through the collimator lens 321 is bent at a right angle by the rising mirror 306 and enters the objective lens 202. The light condensed by the objective lens 202 is irradiated on an optical disk (not shown) as an optical information recording medium.

The optical disk here is an optical disk that is assumed to be recorded / reproduced with red light such as a DVD. The light reflected and diffracted by the optical disk passes through the objective lens 202 and the collimator lens 321 again, is reflected by the wedge prism 320, and enters the LDPD module 205 for DVD. The photodetector in the LDPD module 205 for DVD outputs an electrical signal corresponding to the amount of light received. Next, the third optical system is an infrared optical system formed by the optical elements from the LDPD module 206 to the objective lens 202 in which an infrared semiconductor laser and a photodetector are integrated. .

The CD LDPD module 206 emits light having a wavelength of about 790 nm, which is the third wavelength λ 3. This wavelength varies depending on the individual laser and the type, and may be about 770 nm and about 820 nm. The light emitted from the LDPD module 206 passes through the wedge-shaped prism 320 and is made into substantially parallel light by the collimator lens 321. The light transmitted through the collimator lens 321 is bent at a right angle by the rising mirror 306 and enters the objective lens 202. The light condensed by the objective lens 202 is irradiated onto an optical disk as an optical information recording medium. The optical disk here is an optical disk that is assumed to be recorded and reproduced with infrared light, such as a compact disk (CD). The light reflected and diffracted by the optical disk again passes through the objective lens 202 and the collimator lens 321, passes through the wedge-shaped prism 320, and enters the LDPD module 206 for CD. The photodetector in the CD LDPD module 206 outputs an electrical signal corresponding to the amount of light received.

Note that the wedge-shaped prism 320 is provided with a wavelength-selective film that reflects light having a red wavelength and transmits light having an infrared wavelength. The objective lens 202 is designed so that the aberration is reduced when the base material thickness of the disk is 0.6 mm because red light is optimal for DV D, and infrared light is optimal for CD. It is designed so that the aberration is reduced when the disk substrate thickness is 1.2 mm.

In the above configuration, in the optical head device 100, the blue semiconductor laser 203 corresponds to the first light source of the present invention, and the LDPD module 205 for DVD corresponds to the second light source of the present invention. The LDPD module 206 for use corresponds to the third light source of the present invention. The objective lens 201 corresponds to the first objective lens of the present invention, and the objective lens 202 corresponds to the second object lens of the present invention. Further, the photodetector 204, the LDPD module 205 for DVD, and the LDPD module 206 for CD each correspond to the detection unit of the present invention, and the optical base 120 corresponds to the optical base of the present invention.

This correspondence is the same in each of the following embodiments.

[0064] The optical head device according to the first embodiment having the above-described configuration is configured to transmit a light beam incident on the objective lens 201 between the first optical system and the second and third optical systems. Diameter, objective lens The diameter is smaller than the diameter of the light beam incident on the lens 202.

Hereinafter, description will be given with reference to FIG. FIG. 3 is a schematic configuration diagram of an optical system in the vicinity of each objective lens of the optical head device. The same or corresponding parts as those in FIGS. 1 and 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

[0066] As described as a problem in the prior art, the first optical system that is a blue optical system has an objective that uses a shorter wavelength of light than the second and third optical systems that are red optical systems. lens

Since the numerical aperture (NA) of 201 is as high as 0.85, for example, the depth of focus becomes shallow.

For this reason, in order to perform stable focus control, the magnification of the optical system on the detection side constituted by each optical element from the objective lens 201 to the photodetector 204 is increased, so that the change of the focus error signal is increased. It is necessary to take it out as a thing.

[0068] At this time, the focal length on the detection side of the first optical system needs to be longer than the focal length on the detection side of the second optical system, which leads to an increase in the size of the entire optical system.

On the other hand, the magnification of the optical system on the detection side is determined by the focal length of the optical system and the focal length of the objective lens.

Therefore, by making the focal length of the objective lens 201 of the first optical system that is a blue optical system shorter than the focal length of the objective lens 202 of the second and third optical systems that are red optical systems. In the optical system on the detection side, it is possible to prevent the focal length from increasing while ensuring the magnification. As a result, the optical head device can be miniaturized.

[0071] Generally, the diameter of the light beam passing through the objective lens is determined by (focal length of the objective lens) X (numerical aperture (NA) of the objective lens).

Therefore, the diameter of the light beam at the passage surface of the objective lens 201 of the first optical system is smaller than the diameter of the light beam at the passage surface of the objective lens 202 of the second and third optical systems. By doing so, the focal length of the objective lens can be shortened, and the focal length on the detection side can be shortened. Specific methods for narrowing down the diameter of the light beam include shaping by the beam shaper 301, or inserting a relay lens in the optical path immediately after the blue semiconductor laser 203, and the like.

For example, if the numerical aperture (NA) of the objective lens 201 of the first optical system is 0.85 and the focal length is 1.3 mm, the light beam on the passing surface of the objective lens 201 has a radius rl = l. 105mm, diameter dl = 2.21mm, and the numerical aperture (NA) of the objective lens 202 of the second and third optical system is 0.64.

When the focal length is 2.3 mm, the light beam at the passing surface of the objective lens 202 has a radius r2 = l

472mm, diameter d2 = 2. 944mm, and relational force S of d2> dl is established.

[0074] In this case, the focal length of the collimator lens 305 of the first optical system is set to 18 mm, and a magnification of 13.8 times can be secured. The distance from the objective lens 201 to the light source and the photodetector is the same as that of the collimator lens 305. It is about 36mm, which is about twice the focal length.

[0075] As shown in Fig. 2, if the optical system is bent halfway, Ll = 24.5mm, L2 = 2

This is enough to fit the optical head device within the distance of the standard guide shaft of 3mm.

[0076] If the focal length of the objective lens 201 is set to 2.3 mm, which is the same as that of the second and third optical systems, and the magnification of the optical system on the detection side is set to 13.8 times as in the above case, the collimator lens 305 The focal distance of the lens is 31.7 mm, and the distance from the objective lens 201 to the blue semiconductor laser 203 and the photodetector 204 exceeds 60 mm! /, And the optical head device becomes large.

[0077] Further, if the diameter of the light beam is the same as that of the second and third optical systems, the focal length of the objective lens 201 of the first optical system is 1.73 mm, and the above-mentioned optical system on the detection side is As in the case 13. To obtain a magnification of 8 times, the focal length of the collimator lens 305 is 23.9 mm, and the distance from the objective lens 201 to the blue semiconductor laser 203 and the photodetector 204 is about 48 mm. It is nearly twice as large and difficult to fit in standard size.

As described above, according to the present embodiment, the diameter of the light beam on the passage surface of the objective lens of the first optical system that is the blue optical system is set to the second and second values that are the red Z infrared optical system. By making the diameter smaller than the diameter of the light beam on the passing surface of the objective lens of the optical system 3, it is possible to prevent the increase of the focal length and to reduce the size of the optical head device while ensuring the magnification of the optical system on the detection side it can.

[0079] As shown in FIG. 3, the lens diameter (outer diameter or effective diameter) of the objective lens 201 is preferably smaller than the lens diameter (outer diameter or effective diameter) of the objective lens 202! This is because the diameter of the light beam can be reduced and the objective lens 201 itself can be further downsized. However, the present invention is not limited by the lens diameter of the objective lens, and the lens diameter may be greater than or equal to those for DVD. Furthermore, according to the present embodiment, the focal length of the objective lens 202 of the second and third optical systems is longer than the focal length of the objective lens 201 of the first optical system. Thereby, the working distance (WD2) of the objective lens 202 can be made larger than the working distance (WD1) of the objective lens 201. This has the effect of preventing collision between the disc and the objective lens 202 when recording or reproducing a disc such as a DVD.

[0081] In the above configuration, the objective lens 201 used in the first optical system and the objective lens 202 used in the second optical system and the third optical system are used. The present invention is not limited to this configuration.

[0082] In an optical head device including a plurality of light sources that emit light having different wavelengths and a plurality of objective lenses that collect the light from these light sources onto an optical information recording medium, If the beam diameter of the light passing through the corresponding objective lens is larger than the beam diameter of the light passing through the objective lens corresponding to light having a longer wavelength, the number of light sources and the objective lens It is not limited by the number. As in this embodiment, the number of light sources and the number of objective lenses need not be the same.

[0083] (Embodiment 2)

The optical head device according to the second embodiment of the present invention relates to the layout of each optical system in the optical base, and the configuration is the same as in the first embodiment. Therefore, it will be explained with reference to Fig. 1.

As described in the first embodiment, the optical head device 100 is disposed between the pair of shafts 110 and 111 which are guide shafts by holding the bearings 121 to 123 in the optical information device. .

Here, the shafts 110 and 111 correspond to a pair of shafts of the present invention, and the bearings 121, 122 and 123 correspond to the bearings of the present invention.

As shown in FIG. 1, in the optical head device 100, the objective lens 20 of the second and third optical systems.

2 is a reference line whose center passes through the center of the optical disk (not shown) and is parallel to the shaft 110.

The first optical system is arranged on the shaft 110 side, and the second optical system and the third optical system are arranged on the shaft 111 side.

[0087] As shown in FIG. 2, the second optical system and the third optical system have a relatively low information density. Since the information is recorded and reproduced on an optical disk such as a DVD or CD, the optical system can be relatively simplified.

[0088] On the other hand, the first optical system records and reproduces information on a BD or the like having a relatively high information density. Therefore, the beam shaper 301 is not necessary in the second and third optical systems. It is necessary to provide a filter switching element 302, a collimator lens driving element 304, etc., and the optical system is complicated.

Therefore, in the present embodiment, the distance L1 from the reference line A passing through the center of the objective lens 202 of the optical base 120 to the shaft 110 on which the shaft bearings 121, 121 with the blue semiconductor laser 203 are placed is L1. The reference line A is longer than the distance L2 of the shaft 111 on which the shaft bearing 123 with the LDPD module 205 for DVD and the LDPD module 206 for CD is placed.

[0090] As shown in FIG. 1, the area of the optical base 120 is asymmetrically divided with respect to the reference line A, and the first optical system having a complicated configuration is formed on the wide area side of the width L1. The second and third optical systems having a simpler configuration are formed on the narrow area side of the width L2.

[0091] Thereby, while stably supporting the optical base 120, a useless space can be omitted and the optical head device can be made compact.

In the configuration shown in FIG. 1, the bearing is provided with two bearings 121 and 122 at the end of the first optical system of the optical base 120, and at the ends of the second and third optical systems. However, the structure of the bearing according to the present invention is not limited to this, as long as it is provided at least one at each end of the optical base and can hold the shaft. It is not limited by the number or specific configuration.

In the above configuration, the center of the objective lens 202 of the second and third optical systems forms the rotation center O of the motor 112 and the reference line A, so that the moving axial force of the objective lens 202 is It matches the radius of the optical disk. This is because the third optical system force 3 beam tracking method for CD recording and playback is adopted.

[0094] This will be described below. As shown in Fig. 4 (a), a three-beam diffraction grating 501 is attached to the CD LDPD module 206! /. The light beam emitted from the LDPD module 206 for CD passes through the diffraction grating 501 and splits into one main beam and two sub beams. Is done.

As shown in FIG. 4B, the three light beams are condensed by the objective lens 202 to form one main spot 502 and two sub spots 503 and 504 on the optical disc.

[0096] Fig. 4 (c) shows the relationship between the three spots on the optical disc and the track. When the main spot 502 is located at the center of the track 510 on which information is recorded or reproduced, the sub-spots 503 and 504 are located between the track 510 and the track 511 or 512 adjacent to the track 510, respectively.

The light reflected and diffracted by the optical disk returns to the LDPD module 206 for CD again, and the push-pull signal of each light beam is detected. A tracking signal is generated by multiplying the push-pull signal of the main spot 502 by the coefficient and subtracting the sum of the push-pull signals of the subsbots 503 and 504 (differential bushbull method).

[0098] Thus, in the tracking system of the three beam system that obtains tracking signals using three light beams, the objective lens 202 that emits the three light beams by the optical head device is parallel to the shaft and the motor 112 Ideally, it should be on a straight line through the center. If the objective lens is not on this straight line, the projected image of the optical disk track will be relative to the position of the three light beams when the optical head device is near the inner periphery and the outer periphery of the optical disc. This is because if the projected image of the rotating track is relatively rotated, the relative positional relationship of the main beam and the sub beam with respect to the track changes, the amplitude changes, and the quality of the tracking signal decreases.

In addition, as described in the first embodiment, the optical base 120 is provided with an arc-shaped cutout portion 100a in order to prevent the optical base 120 from colliding with the motor 112. The center of the circular arc of the notch 100a is provided on the reference line A for matching. Thereby, the moving range of the objective lens 202 in the radial direction can be maximized.

[0100] Note that since the BD and DVD usually employ the one-beam tracking method, the objective lens 201 does not need to be disposed on the reference line A in the first optical system. The same applies to the objective lens 202 in the second optical system.

Next, each optical element constituting the first optical system formed in the area of the width L1 will be described in detail. [0102] The beam shaper 301 corresponds to the beam shaping unit of the present invention, and has a substantially cylindrical surface in which the symmetric axes are parallel on both the incident surface and the output surface, and is one of the two axes perpendicular to the optical axis of the incident light. Enlarge the ray only in one axial direction. The light emitted from the blue semiconductor laser 203 corrects the difference in the intensity distribution due to the direction by the action of the force beam shaper 301 having a difference in the intensity distribution of the light depending on the direction of the active layer of the laser, and approaches the uniform. Due to the nature of the beam shaper 301, astigmatism occurs when the distance from the light emitting point deviates from the design value. The ratio depends on the design, but astigmatism of about 10m λ occurs with a change of 1 micron. For this reason, it is desirable to arrange the blue semiconductor laser 203 as close as possible to the beam shaper 301. This is because the absolute value of the changing distance can be reduced even if the material supporting the light source and the beam shaper expands or contracts due to temperature changes.

Next, the filter switching element 302 will be described with reference to FIGS. 5 (a) and 5 (b).

[0104] The filter switching element 302 corresponds to the dimming unit of the present invention, and two types of ND filters 311 and 312 having different transmittances are provided in directions in which light passing surfaces are perpendicular to each other. The The transmittance of the ND filter 311 is 50%, and the transmittance of the ND filter 312 is 100%. The filter switching element 302 is rotated 90 degrees by passing an electric current. In FIG. 5 (a), the A surface in the figure faces upward, and incident light passes through the ND filter 311. On the other hand, FIG. 5 (b) shows a state rotated 90 degrees toward the front. In FIG. 5B, the A surface faces forward, and incident light passes through the ND filter 312.

[0105] In this way, by changing the ND filter, the transmittance of the light passing therethrough is changed.

This is to achieve both recording on a dual-layer disc and ensuring a signal-to-noise ratio (SN ratio) during single-layer disc playback. In the case of a dual-layer disc, etc., it is necessary to increase the light utilization efficiency and to collect a sufficient amount of light on the disc during recording. With this transmittance, the light on the disc is strong when reproducing a single-layer disc. There is a possibility that information will be erased during playback. However, if the amount of light output from the blue semiconductor laser 203 is reduced to avoid this, the noise of the blue semiconductor laser 203 increases, and the SN ratio of the reproduction signal necessary for information reproduction cannot be obtained. Therefore, the filter switching element 302 is used to switch the type of ND filter through which light passes according to the type of optical disk to be reproduced. During single-layer reproduction, light from the blue semiconductor laser 203 is effective by passing it through the ND filter 311. The rate is reduced, and the light output from the objective lens 201 is reduced while the output from the blue semiconductor laser 203 remains constant. On the other hand, when reproducing a double-layer disc or the like, the light passes through the ND filter 312 and guides light with high efficiency and light quantity to the objective lens 201.

Next, FIG. 5B shows the configuration of the collimator lens driving element 304. The collimator lens 305 is held by a holder 305a, and this holder 305a is supported by shafts 305b and 305c, and can be moved along the shafts 305b and 305c by a transmission system such as a motor and a feed screw (not shown). As a result, the distance between the collimator lens 305 and the blue semiconductor laser 203 is changed, and the degree of convergence of the light after passing through the collimator lens is changed to give the light a spherical aberration in a direction for canceling the spherical aberration generated on the optical disk. be able to. The collimator lens driving element 304, the collimator lens 305, and the holder 305a constitute the spherical aberration correcting means of the present invention. The collimator lens 305 alone constitutes the collimator lens of the present invention.

[Embodiment 3]

The optical head device according to the third embodiment of the present invention relates to the layout of each optical element constituting the first optical system. The configuration is the same as in the first embodiment. Therefore, description will be made with reference to FIGS.

As described in the second embodiment, each optical element in the first optical system has the beam shaper 301 next to the blue semiconductor laser 203 as the light source, and then the filter switching element on the light emission side. 302, then the polarizing beam splitter 303, then the collimator lens 305, and finally the objective lens 201. The deflecting beam splitter 303 corresponds to a branching portion of the present invention.

[0109] The reason for the above layout is as follows.

[0110] The beam shaper 301 defines the cross-sectional shape of the light beam in the first optical system, and since it is necessary to determine the shape within the area of the cross-sectional shape is small, the blue semiconductor laser 203, which is the light source, is used. It is desirable for the distance to be short. Therefore, it is arranged immediately after the blue semiconductor laser 203. Next, as described in the second embodiment, the filter switching element 302 is for adjusting the light amount of the light beam incident on the optical disc. It is not necessary to put in the optical system on the detection side. So light It is arranged in front of the deflecting beam splitter 303 for branching the reflected light from the disk to the photodetector 204. Next, the deflecting beam splitter 303 and the collimator lens 305 are arranged in this order for the following reason. By disposing the collimator lens 305 after the deflecting beam splitter 303, the collimator lens 305 is shared by both optical systems on the light emission side and the reflection side. As a result, the number of optical elements in the first optical system is reduced, and the conjugate relationship between the photodetector 204 and the blue semiconductor laser 203 does not change even if the position of the collimator lens 305 is driven to correct spherical aberration. There are advantages.

[0111] From the above, in the present embodiment, the first optical system has the blue semiconductor laser 203, the beam shaper 301, the filter switching element 302, the polarization beam splitter 303, the collimator lens on the light emission side. It is desirable to arrange 305 and objective lens 201 in this order.

[0112] When an optical element other than the deflection beam splitter, such as a hologram, is used as the branching portion of the present invention, it may be provided on the objective lens 201 side after the collimator lens 305. In this case, the arrangement order of the entire optical elements in the first optical system is blue semiconductor laser 203, beam shaper 301, filter switching element 302, collimator lens 305, polarization beam splitter 303, and objective lens 201.

[0113] (Embodiment 4)

The optical head device according to the fourth embodiment of the present invention is characterized by the shape of the rising mirror 306. FIG. 6A is a perspective view showing a configuration in the vicinity of the rising mirror 306. FIG. 6B is a side view of the raising mirror 306. FIG. 6C is a side view for schematically showing the state of incident light on the rising mirror 306.

[0114] A description will be given below. As shown in FIG. 6 (a), the rising mirror 306 has a first reflecting surface 306a that reflects light to the first optical system and guides the light to the objective lens 201, and a second optical system. A second reflecting surface 306b that reflects light and guides it to the objective lens 202 is provided. The first reflecting surface 310a is provided with a reflecting film that maximizes the reflectivity when blue light is incident at an incident angle of approximately 45 degrees. The second reflecting surface 306b is provided with a reflecting film that maximizes the reflectance when red light or infrared light is incident at an incident angle of about 45 degrees.

Further, as shown in FIG. 6B, in the rising mirror 306, the first reflecting surface 306a and the second reflecting surface 306a The first reflecting surface 30 has a substantially right isosceles triangle having a first reflecting surface 306a, a second reflecting surface 310b, and a bottom surface 306e. 6a and the second reflecting surface 306b are joined to the bottom surface 306e by a joint portion that does not form a side parallel to the first reflecting surface 306 and the second reflecting surface 306b. Each is chamfered. Therefore, the side shape is strictly a pentagon.

[0116] Further, since the chamfering amount C1 by the surface 306c and the chamfering amount C2 by the surface 306c are different in size, the side surfaces of the rising mirror 306 are formed by the first reflecting surface 306a and the second reflecting surface 306b. It forms an asymmetric pentagonal shape with respect to the perpendicular bisector B.

[0117] With this structure, the operator can determine which of the two reflecting surfaces of the rising mirror 306 is the first reflecting surface 306a or the second reflecting surface 306b by assembling. It can be easily discriminated visually or by touch.

[0118] Conventionally, a triangular prism-like mirror such as the rising mirror 306 has a symmetrical shape with respect to the bisector of the angle formed by the reflecting surface thereof. If the reflecting surface is installed in the wrong direction in the optical head device, the desired reflectance cannot be obtained. The first and second reflective surfaces are not easy to discern due to differences in the type of reflective film, if the surfaces are thin and appear greenish or reddish.

[0119] On the other hand, in the present embodiment, each reflecting surface can be easily discriminated by making the shape of the side surface asymmetrical.

In the present embodiment, the force that makes the chamfering amount C1 on the first reflecting surface 306a side larger than the chamfering amount C2 on the second reflecting surface 306b side has the following effects. That is, as shown in FIG. 6 (c), in the first optical system, the collimator lens 305 is a force collimator lens drive element 304 fixed on the collimator lens drive element 304, and the rising mirror 306. Are arranged on the same plane, the chamfering amount C1 of the first reflecting surface 306a can be included in the movable range of the collimator lens driving element 304 as it is.

[0121] As described in Embodiment 1, the diameter of the light beam in the first optical system is smaller than the diameter of the second light beam. Therefore, even if the first reflecting surface 306a has a smaller area than the second reflecting surface 306b, the rising mirror 306 can guide the incident light of each optical system to the corresponding objective lens. It should be noted that the rising mirror 306 is a force corresponding to the rising mirror of the present invention, and its configuration is not limited to the above description. The chamfering amount C2 may be larger than the chamfering amount C1. Also, either the first reflecting surface 306a or the second reflecting surface 306b is chamfered and the other is not chamfered.

Further, in the configuration shown in FIGS. 6 (a) and 6 (b), the chamfering is performed on the whole of the joint portion with the bottom surface 306e for each of the first reflecting surface 306a and the second reflecting surface 306b. However, it may be performed only for a part. That is, the asymmetric side surface shape of the rising mirror 306 is formed in a part of the rising mirror 306. As an example, FIG. 7 shows a configuration in which only the central portion of the second reflecting surface 306b is chamfered to provide a surface 306d, and both ends are not chamfered.

In short, if the first reflecting surface 306a and the second reflecting surface 306b are asymmetrical shapes that can be directly discerned by visual or tactile sense, they are limited by the size, position, and range of the respective chamfering amounts. It will never be done.

In the first to fourth embodiments described above, the method of changing the position of the collimator lens is described as an example of the spherical aberration correction unit of the present invention. However, the liquid crystal is used for light equivalent to spherical aberration. You can correct it by giving a wavefront, or you can combine convex and concave lenses like a beam expander and change the distance to change the degree of light divergence to correct spherical aberration. Even in these cases, the effect of the invention of the present embodiment is not disturbed! /.

In Embodiments 1 to 4 described above, the beam shaper as the beam shaping unit of the present invention is different in two directions, such as a force toric surface in which the incident surface and the output surface are substantially cylindrical surfaces. Beam shaping may be performed by a surface having the following power. Even in that case, the effect of the invention of the present embodiment is not disturbed.

[0127] Also, in the above-described first to fourth embodiments, the force ND filter showing a configuration in which the ND filter is replaced by rotation as the dimming unit of the present invention may be configured to translate and replace the ND filter. A liquid crystal and a polarizing plate may be used. These methods do not disturb the effects of the invention of the present embodiment.

[0128] In Embodiments 1 to 4 described above, the power shown as an example in which the third optical system of the present invention includes an LDPD module for CD, which is a light source that emits the third wavelength λ3. Is the first The same effects as in this embodiment can be obtained even if two types of light sources and optical systems that emit the wavelength and the second wavelength are provided.

Further, in the present embodiment, the force shown in the example in which the objective lens 201 and the objective lens 202 are separated and arranged in the tangential direction of the optical disc is not limited to this, as shown in FIG. The objective lens 201 and the objective lens 202 may be configured so that the objective lenses are aligned in the radial direction.

[0130] Further, the objective lens 201 and the objective lens 202 may be used as one objective lens, that is, the objective lens may be shared by the first to third optical systems. In this case, in the optical head device 100, the actuator 200 has a single objective lens, and instead of the rising mirror 306, the light beam from each light source is the same lens in the same direction and the same optical axis. Use a start-up prism.

FIG. 9 is a perspective view of such a rising prism 401. The rising prism 401 is a means for reflecting light having different wavelengths incident from two directions as light having the same direction and the same optical axis.

[0131] In the rising prism 401, the reflection surface 402 has a color selective reflection film that transmits red (near 660nm) 'infrared (near 780ηm) and reflects blue (near 405nm) light. It is formed.

On the other hand, on the reflection surface 403, a color selective reflection film is formed which transmits blue (near 405 nm) light and reflects red (near 660 nm) ′ infrared (near 780 nm). As a result, light of different wavelengths that are incident in two opposite directions are reflected toward the same objective lens in the same optical axis and direction.

FIGS. 10 (a) and 10 (b) schematically show the operation of the optical head device 100 when the rising prism 401 is incorporated.

FIG. 10 (a) shows a case where the light beam from the blue semiconductor laser 203 is irradiated when used as the first optical system. The blue light beam is collimated by the collimator lens 350 and enters the rising prism 401. The incident blue light beam is reflected by the reflecting surface 402 that reflects blue light, and enters the common objective lens 410. When the common objective lens 410 receives a blue light beam, it generates convergent light suitable for BD recording and playback. Irradiate BD411. The light reflected and diffracted by the BD 411 passes through the common objective lens 410 again, is reflected by the reflecting surface 402 of the rising prism 401, passes through the collimator lens 305, and travels to the detection-side optical system.

On the other hand, FIG. 10 (b) shows a case where the light beam from the LDPD module 205 for DVD is irradiated when used as the second optical system. The red light beam is collimated by the collimator lens 32 1 and enters the rising prism 401. The incident red light beam is reflected by the reflecting surface 403 that reflects the red light and enters the common objective lens 410.

When the common objective lens 410 receives a red light beam, the common objective lens 410 generates converged light suitable for DVD recording / playback, and irradiates the DVD 412 with this light. The light reflected and diffracted by the DVD 412 passes through the common objective lens 410 again, is reflected by the reflecting surface 403 of the rising prism 401, passes through the collimator lens 321, and returns to the DVD LDPD module 205. When it is used as the third optical system, it collects light on the CD in the same manner as shown in Fig. 10 (b).

[0135] In this way, if the rising prism 401 and the common objective lens 410 are used, one objective lens can be shared by the first to third optical systems to support three types of optical disks. In addition to the effects of the second embodiment, the number of optical components can be reduced.

[Embodiment 5]

Embodiment 5 of the present invention is an optical information device that mounts the optical head device of Embodiments 1 to 4 and that only records and reproduces or reproduces signals with respect to an optical disc.

FIG. 11 schematically shows the configuration of the optical information device 600 according to the fifth embodiment. In FIG. 11, the same or corresponding parts as in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted. 601 is an electric circuit, 602 is a clamper, and 603 is a turntable.

In FIG. 11, the optical disc 604 is placed on the turntable 603 and rotated by the motor 112. The optical head device 100 coarsely moves on the shaft 110 to a track where desired information of the optical recording medium 209 exists.

The optical head device 100 also sends a focus error signal and a tracking error signal to the electric circuit 601 corresponding to the positional relationship with the optical disc 604. In response to this signal, the electric circuit 601 sends a signal for finely moving the objective lens 202 or 201 corresponding to the optical disk 604 to the optical head device 100. By this signal, the optical head device 100 causes the optical disc 60 to 4 performs focus control and tracking control, and reads / writes (records) or erases information on the optical disk 604.

[0140] In the above configuration, the optical information device 600 corresponds to the optical information device of the present invention, and the electric circuit 601 corresponds to the electric circuit of the present invention.

[0141] As described above, the present embodiment uses the optical head device of Embodiments 1 to 4 as the optical head device, so that the internal volume is also reduced with the miniaturization of the optical head device. When it is downsized as a whole, it has a habit effect.

(Embodiment 6)

FIG. 12 shows an embodiment of a computer provided with the optical information device described in the fifth embodiment.

In FIG. 12, a personal computer (computer) 1000 includes the optical information device 600 according to the fifth embodiment, a keyboard 1003 for inputting information, and a monitor 1002 for displaying information.

[0143] A computer having the optical information device 600 of Embodiment 5 described above as an external storage device has the effect that information can be stably recorded or reproduced on different types of optical disks, and can be used in a wide range of applications. Become. Optical disks make use of their large capacity to back up hard disks in computers, media (optical disks) are inexpensive and easy to carry, and information can be read by other optical information devices. You can make use of the compatibility to exchange programs and data with people or carry them around for yourself. It can also support playback and recording of existing media such as BD, DVD and CD.

[0144] Further, by providing the optical information device 600 of the fifth embodiment that is smaller than the conventional one, the size can be further reduced.

(Embodiment 7)

FIG. 13 shows an embodiment of an optical disk recorder (video recording apparatus) provided with the optical information apparatus described in the fifth embodiment.

In FIG. 13, an optical disk recorder (video recording apparatus) 1010 includes the optical information apparatus 600 of Embodiment 5 (not shown), and a monitor 1011 for displaying the recorded video. Used in connection with. [0146] The optical disc recorder provided with the optical information device 600 of the above-described fifth embodiment has an effect that video can be stably recorded or reproduced on different types of optical discs and can be used in a wide range of applications. An optical disk recorder can record video on media (optical disk) and play it back whenever you like. On an optical disk, after recording or recording a program that requires rewinding after recording, such as tape, follow-up playback that plays back the beginning of the program, or program that was previously recorded while recording a program. Simultaneous recording and playback is possible. By taking advantage of the fact that the media (optical disc) is cheap and easy to carry, and that other optical disc recorders can read information, the recorded video can be exchanged with people or carried for yourself. can do. It also supports playback and recording of existing media such as BD, DVD, and CD.

[0147] Further, by providing the optical information device 600 of the fifth embodiment that is smaller than the conventional one, the size can be further reduced.

[0148] Although only the optical information device 600 is described here, a hard disk may be incorporated or a video tape recording / playback function may be incorporated. In that case, the video can be temporarily saved and knocked up easily.

[Embodiment 8]

FIG. 14 shows an embodiment of an optical disc player (video playback device) provided with the optical information device 600 described in the fifth embodiment.

[0150] In FIG. 14, an optical disc player (video playback device) equipped with a liquid crystal monitor 1020.

) 1021 incorporates the optical information device 600 of the fifth embodiment (not shown), and can display the video recorded on the optical disk on the liquid crystal monitor 1020.

[0151] The optical disc player including the optical information device 600 of the above-described fifth embodiment has an effect that video can be stably reproduced on different types of optical discs and can be used for a wide range of purposes.

[0152] The optical disc player can play the video recorded on the medium (optical disc) at any time. An optical disc does not require a rewinding operation after reproduction like a tape, and can access and reproduce an arbitrary place of a video. It also supports playback of existing media such as BD, DVD and CD. [0153] Further, by providing the optical information device 600 of the fifth embodiment that is smaller than the conventional one, the size can be further reduced.

[Embodiment 9]

FIG. 15 shows an embodiment of a server provided with the optical information device 600 described in the fifth embodiment.

In FIG. 15, a server 1030 includes the optical information device 600 according to the fifth embodiment, a monitor 1033 for displaying information, and a keyboard 1034 for inputting information, and is connected to a network 1035. ing.

[0156] The server having the optical information device 600 of Embodiment 5 described above as a plurality of external storage devices has the effect that information can be stably recorded or reproduced on different types of optical disks, and can be used for a wide range of applications. It will be a thing. The optical disk drive takes advantage of its large capacity to send information (images, audio, video, HTML documents, text documents, etc.) recorded on the optical disk in response to a request from the network 1035. It also records the information sent to the network at the requested location. In addition, since information recorded on existing media such as BD, DVD disc and CD disc can be reproduced, it is also possible to send such information.

[0157] Further, by providing the optical information device of the fifth embodiment that is smaller than the conventional one, the size can be further reduced.

[Embodiment 10]

FIG. 16 shows an embodiment of a car navigation system provided with the optical information device described in the fifth embodiment.

In FIG. 16, a car navigation system 1040 incorporates the optical information device 600 of Embodiment 5 (not shown) and is connected to a liquid crystal monitor 1041 for displaying topography and destination information. used.

[0160] The car navigation system including the optical information device 600 according to the fifth embodiment described above can stably record or play back images on different types of optical disks, and has the effect of being usable in a wide range of applications. It will be a thing. The car navigation system 1040 uses map information recorded on the media (optical disk), ground positioning system (GPS), gyroscope, Based on information from speedometer, odometer, etc., the current position is determined and displayed on the LCD monitor. When the destination is entered, the optimum route to the destination is determined based on the map information and road information and displayed on the LCD monitor.

[0161] By using a large-capacity optical disc for recording map information, a single disc can cover a wide area and provide detailed road information. In addition, information about restaurants, convenience stores, gas stations, etc. associated with the vicinity of the road can also be stored on an optical disc and provided. In addition, the road information is getting old and the power that doesn't match the reality. Optical discs are compatible and inexpensive, so you can get the latest information by exchanging with a disc containing new road information. Can do. It can also play and record existing media such as BD, DVD discs and CD discs, so you can watch movies and listen to music in the car.

[0162] Further, by providing the optical information device 600 of the fifth embodiment that is smaller than the conventional one, the size can be further reduced, and this is particularly effective in the vehicle.

Industrial applicability

The optical head device and the optical information device according to the present invention have an effect that can be reduced by downsizing the optical system. The optical head device, the optical head device, the optical information device, and their applications As a product, it can be used as a computer, disc player, server, car navigation system, optical disc recorder, etc., and is useful as a recording / playback device for video, music and other information.

Claims

The scope of the claims

[1] a plurality of light sources that emit light having different wavelengths from each other;

A plurality of objective lenses for condensing the light of the plurality of light source powers onto the corresponding optical information recording medium, and

The diameter of the light from the plurality of light sources at the passing surface of the objective lens to which each light corresponds corresponds to an optical head device having a shorter wavelength than a longer wavelength.

[2] The plurality of light sources are two light sources, a first light source that emits a wavelength of λ 1 and a second light source that emits light of a wavelength λ 2 longer than the wavelength λ 1,

The plurality of objective lenses are two objective lenses, a first objective lens that collects light from the first light source and a second objective lens that collects light from the second light source. The first objective lens has a higher numerical aperture than the second objective lens, and the diameter of the light of the first light source power on the passing surface of the first objective lens is the second objective lens. 2. The optical head device according to claim 1, wherein the optical head device is smaller than a diameter of light of the second light source power on a lens passing surface.

[3] The optical head device according to [2], wherein a lens diameter of the first objective lens is smaller than a lens diameter of the second objective lens.

[4] The distance WD1 by which the first objective lens can move with respect to the surface of the optical information recording medium on which recording or reproduction is performed by the light of the first light source, and the light of the second light source 3. The optical head according to claim 2, wherein there is a relationship of WDKWD2 with a distance WD2 that the second objective lens can move with respect to the surface of the optical information recording medium on which recording or reproduction is performed. apparatus.

[5] A bearing for holding at least a pair of shafts for moving the optical base between the inner peripheral side and the outer peripheral side of the optical information recording medium,

At least one of the bearings is disposed at both ends of the optical base, and the base parallel to the pair of shafts passes through at least the center of the second objective lens. There is a relationship of L1> L2 between the distance LI between the quasi-line and one of the pair of shafts and the distance L2 between the reference line and the other of the pair of shafts,

The first light source is provided on the one side of the one shaft,

3. The optical head device according to claim 2, wherein the second light source is provided on the other side of the one shaft.

6. The optical head device according to claim 5, wherein the reference line passes through a rotation center of a motor that rotates the optical information recording medium.

7. The optical head device according to claim 6, wherein the reference line also passes through the center of the first objective lens.

[8] As seen from the plane including the pair of shafts,

The first optical system including the first light source and the first objective lens is formed to be within the width of the distance L1, and the second optical system including the second light source is the first optical system. 7. The optical head device according to claim 6, wherein the optical head device is formed so as to be within a width of the distance L2 except for the objective lens of 2 and a rising mirror for guiding light to the second objective lens. .

[9] The optical base has an arc-shaped notch,

6. The optical head device according to claim 5, wherein the arc of the notch is provided so that a center thereof passes through the reference line.

10. The optical head device according to claim 5, wherein the first objective lens is disposed closer to the first light source than the second objective lens.

[11] A light source having a wavelength λ3 longer than the wavelength λ2, and further comprising a third light source provided near the other of the one shaft,

6. The optical head device according to claim 5, wherein a third optical system including the second objective lens and the third light source is formed.

12. The optical head device according to claim 11, wherein the reference line passes through a rotation center of a motor that rotates the optical information recording medium.

13. The optical head device according to claim 5, wherein the wavelength λ 1 is 450 nm or less.

[14] Output from the first light source provided between the first light source and the first objective lens. 6. The optical head device according to claim 5, further comprising a beam shaping unit that corrects the intensity distribution of the light.

[15] A sphere that is provided between the first light source and the first objective lens and corrects spherical aberration that occurs when the light is focused on the optical information recording medium emitted from the first objective lens. 6. The optical head device according to claim 5, further comprising a surface aberration correction unit.

[16] The range of claim 5, further comprising a dimming unit that is provided between the first light source and the first objective lens and controls the transmittance of light emitted from the first light source. The optical head device described

[17] a beam shaping unit that receives light of the first light source power and corrects the intensity distribution;

A light control unit for controlling the light transmittance;

A collimator lens that shapes incident light into substantially parallel light;

The light emitted from the first light source is disposed so as to form an optical system that passes in the order of the beam shaping unit, the light control unit, the collimator lens, and the first objective lens. 3. The optical head device according to item 2 of the above item.

[18] The method according to claim 17, further comprising a branching unit that separates light traveling from the first light source toward the optical information recording medium and light traveling from the optical information recording medium toward the detection unit. Optical head device.

[19] A first reflecting surface that reflects light from the first light source and guides it to the first objective lens; and reflects light from the second light source that is orthogonal to the first reflecting surface And a rising mirror having a second reflecting surface that leads to the second objective lens,

The rising mirror is in relation to a bisector of an angle formed by the first reflecting surface and the second reflecting surface when viewed from a surface orthogonal to the first reflecting surface and the second reflecting surface. 3. The optical head device according to claim 2, comprising an asymmetric cross-sectional shape.

[20] The rising mirror has a substantially triangular prism shape,

A side other than the side formed by the first reflective surface and the second reflective surface, and one or all of one or the other of two sides parallel to the first reflective surface and the second reflective surface, or 20. The optical head device according to claim 19, wherein the cross-sectional shape is formed by chamfering a part.

[21] All of the two sides other than the side formed by the first reflecting surface and the second reflecting surface are chamfered.

21. The optical head device according to claim 20, wherein the first reflecting surface side is chamfered more than the second reflecting surface side.

[22] The optical head device according to claim 1,

A motor for rotating the optical information recording medium;

An optical information device comprising: an electric circuit that controls operations of the motor and the light source based on a signal obtained from the optical head device.