JP2010244681A - Optical head device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an optical head device for stably detecting a signal by obtaining an optical element for converting a linear polarized light with two type wavelengths having parallel polarized planes into orthogonally polarized planes. <P>SOLUTION: An organic thin films 14 having birefringence is laminated in two transparent substrates 11 and 16 via adhesive 15. A phase element 101 constructed such that the organic thin film 14 gives a phase difference of 2π(m<SB>1</SB>-1/2) to the polarized light with the one wavelength and phase difference of 2πm<SB>2</SB>to the other polarized light is mounted on the optical head device. The optical axes of two irradiated lights coincides with each other and then each optical component in the optical head device exerts good optical characteristics so that stable signal detection could be achieved with least reading error when reproducing the information on an optical disk and least writing error when writing information on the optical disk. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

本発明は、光ヘッド装置に関する。   The present invention relates to an optical head device.

ＣＤやＤＶＤなどの光ディスクおよび光磁気ディスクなどの光記録媒体の情報の記録・再生を行う光ヘッド装置において、光源である半導体レーザからの出射光はレンズにより光記録媒体上に集光され、光記録媒体で反射し戻り光となる。この戻り光はビームスプリッタを用いて光検出器である受光素子へ導かれ、光記録媒体の情報が電気信号に変換される。   In an optical head device for recording / reproducing information on an optical recording medium such as an optical disk such as a CD or DVD and a magneto-optical disk, light emitted from a semiconductor laser, which is a light source, is condensed on the optical recording medium by a lens. It is reflected by the recording medium and becomes return light. This return light is guided to a light receiving element which is a photodetector using a beam splitter, and information on the optical recording medium is converted into an electric signal.

また、同一の光ヘッド装置を用いて規格の異なる光記録媒体である、ＣＤおよびＤＶＤ光ディスクの情報の記録・再生を行うため、ＣＤ／ＤＶＤ互換の光ヘッド装置が製品化されている。光記録媒体の記録層として光の反射・吸収に対して波長依存性の高い媒質を用いる、ＣＤ−Ｒなどの再生を前提とした光ディスクにおいては、ＣＤに用いる半導体レーザは７９０ｎｍ波長帯のものである。このとき、ＤＶＤ用には６６０ｎｍ波長帯の半導体レーザが用いられている。   Also, CD / DVD compatible optical head devices have been commercialized in order to record / reproduce information on CD and DVD optical discs, which are optical recording media of different standards, using the same optical head device. In an optical disc that uses a medium having a high wavelength dependency with respect to reflection / absorption of light as a recording layer of an optical recording medium and is premised on reproduction such as a CD-R, the semiconductor laser used for the CD has a wavelength of 790 nm. is there. At this time, a semiconductor laser having a wavelength band of 660 nm is used for DVD.

７９０ｎｍ波長帯の半導体レーザと６６０ｎｍ波長帯の半導体レーザを１チップ内に形成したモノリシックな２波長半導体レーザを用いることにより、発光点位置精度が高く、安定した光ヘッド特性を得ることができる。さらに、部品点数を削減して光ヘッド装置の小型化・軽量化が図られ、光学系の設計も簡略化できるなどのメリットが期待できるため、２波長半導体レーザを用いる種々の光ヘッド装置の構成が提案されている。   By using a monolithic two-wavelength semiconductor laser in which a semiconductor laser having a 790 nm wavelength band and a semiconductor laser having a 660 nm wavelength band are formed in one chip, the emission point position accuracy is high and stable optical head characteristics can be obtained. In addition, the optical head device can be reduced in size and weight by reducing the number of components, and advantages such as simplification of the optical system design can be expected. Therefore, various optical head device configurations using two-wavelength semiconductor lasers can be expected. Has been proposed.

図４の２波長半導体レーザを用いるＣＤ／ＤＶＤ互換の光ヘッド装置では、２波長半導体レーザ１における６６０ｎｍ波長帯の発光点１Ａ（図４（ａ））および７９０ｎｍ波長帯の発光点１Ｂ（図４（ｂ））からの出射光は、ビームスプリッタ４を透過し、コリメートレンズ５により平行光となり、対物レンズ６で光記録媒体であるＣＤやＤＶＤなどの光ディスク７の光記録面上に集光される。光ディスク７の光記録面で反射した光は、再び対物レンズ６およびコリメートレンズ５により集光され、ビームスプリッタ４で反射して、光検出器８Ａまたは８Ｂに到達する。   In the CD / DVD compatible optical head device using the two-wavelength semiconductor laser of FIG. 4, the emission point 1A (FIG. 4 (a)) of the 660 nm wavelength band and the emission point 1B of the 790 nm wavelength band in the two-wavelength semiconductor laser 1 (FIG. 4). The light emitted from (b)) passes through the beam splitter 4 and becomes parallel light by the collimator lens 5 and is condensed by the objective lens 6 on the optical recording surface of the optical disk 7 such as CD or DVD as an optical recording medium. The The light reflected by the optical recording surface of the optical disc 7 is again collected by the objective lens 6 and the collimating lens 5, reflected by the beam splitter 4, and reaches the photodetector 8A or 8B.

このとき、図４（ａ）、（ｂ）に示すように、２波長半導体レーザ１上の６６０ｎｍ波長帯の発光点１Ａと７９０ｎｍ波長帯の発光点１Ｂとの位置が異なるため、光検出器へ集光する位置も異なり、６６０ｎｍ波長帯用の光検出器８Ａと７９０ｎｍ波長帯用の光検出器８Ｂとが必要となり、構成が複雑で光ヘッド装置が大型となった。そこで、２つの検出器の受光部面積をカバーできる受光面積の大きい一個の光検出器（図示せず）を用いて両方の波長帯の光を検出する方法もあるが、検出の応答速度が遅く、装置が大型化する問題があった。   At this time, as shown in FIGS. 4A and 4B, the positions of the emission point 1A in the 660 nm wavelength band and the emission point 1B in the 790 nm wavelength band on the two-wavelength semiconductor laser 1 are different. The light condensing positions are different, and a light detector 8A for the 660 nm wavelength band and a light detector 8B for the 790 nm wavelength band are required, and the configuration is complicated and the optical head device becomes large. Therefore, there is a method of detecting light in both wavelength bands using a single photodetector (not shown) having a large light receiving area that can cover the light receiving area of the two detectors, but the detection response speed is slow. There is a problem that the apparatus becomes large.

上記の問題を解決する方法として、２波長半導体レーザからの２つの波長帯の出射光の偏光特性を利用して、２つの出射光の光軸を一致させる光学素子を用いる方法が考えられるが、２つの出射光の偏波面が互いに平行であるため、この２つの出射光を分離することが困難であった。   As a method for solving the above problem, a method using an optical element that matches the optical axes of the two outgoing lights by using the polarization characteristics of the outgoing lights of the two wavelength bands from the two-wavelength semiconductor laser can be considered. Since the polarization planes of the two outgoing lights are parallel to each other, it is difficult to separate the two outgoing lights.

本発明の目的は、発光点位置が異なり、かつ偏波面が互いに平行である２波長半導体レーザからの２つの出射光の光軸を一致させる光学素子を光ヘッド装置に搭載して、構成が複雑でなく、小型・軽量で、さらに検出の応答速度の早い光ヘッド装置を提供することである。   It is an object of the present invention to mount an optical element on an optical head device that matches the optical axes of two emitted light beams from a two-wavelength semiconductor laser having different light emitting point positions and parallel planes of polarization. In addition, the present invention is to provide an optical head device that is small and lightweight and has a quick detection response speed.

本発明は、異なる発光点位置から、それぞれ異なる２種の波長λ_１と波長λ_２（λ_１≠λ_２）で、偏波面が互いに平行な直線偏光を出射する光源と、前記光源からの光を光記録媒体に集光する対物レンズと、前記光記録媒体で反射する光を検出する光検出器と、を備えた光ヘッド装置であって、前記光源と前記対物レンズとの間の光路中、または、前記対物レンズと前記光検出器との間の光路中に、位相子を備え、前記位相子は、少なくとも１枚の透明基板上に固定された複屈折性を有する有機物薄膜と、回折格子と、を有し、前記有機物薄膜は、進相軸が、偏波面が互いに平行な２種の直線偏光の偏光方向に対して４５°傾けて入射するように配置され、前記波長λ_１の直線偏光に対しては２π（ｍ_１−１／２）（ｍ_１は自然数）の位相差を、前記波長λ_２の直線偏光に対しては２πｍ_２（ｍ_２は自然数）の位相差を発生させるリタデーション値に調整されて、前記２種の直線偏光の偏波面が互いに直交化され、前記回折格子は、前記２種の波長の直線偏光のいずれか一方を回折させ、他方を回折させずに前記２種の波長の光の光軸を一致させる光ヘッド装置を提供する。 The present invention includes a light source that emits linearly polarized light with two different wavelengths λ ₁ and λ ₂ (λ ₁ ≠ λ ₂ ) and different polarization planes from different light emitting point positions, and light from the light source. An optical head device comprising: an objective lens that focuses light on an optical recording medium; and a photodetector that detects light reflected by the optical recording medium, in an optical path between the light source and the objective lens Or a phase shifter in an optical path between the objective lens and the photodetector, the phase shifter being a birefringent organic thin film fixed on at least one transparent substrate, and diffraction The organic thin film is arranged so that the fast axis is incident at an angle of 45 ° with respect to the polarization directions of two types of linearly polarized light whose polarization planes are parallel to each other, and the organic thin film has the wavelength λ ₁ For linearly polarized light, a phase of 2π (m ₁ −1/2) (m ₁ is a natural number) The difference is adjusted to a retardation value that generates a phase difference of 2πm ₂ (m ₂ is a natural number) for the linearly polarized light having the wavelength λ ₂ , and the polarization planes of the two types of linearly polarized light are made orthogonal to each other. The diffraction grating provides an optical head device that diffracts one of the linearly polarized light of the two wavelengths and matches the optical axes of the light of the two wavelengths without diffracting the other.

また、前記回折格子は、断面が直角三角形状または階段状となる鋸歯状格子であって、常光屈折率ｎ_ｏと異常光屈折率ｎ_ｅを有する複屈折材料からなり、前記常光屈折率ｎ_ｏと等しく均一な屈折率ｎ_ｓを有する充填接着剤が、前記鋸歯状格子を充填する上記の光ヘッド装置を提供する。 Further, the diffraction grating is a sawtooth grating in cross-section at right angles triangular or stepped, made of a birefringent material having an ordinary refractive index n _o and extraordinary refractive index n _e, the ordinary refractive index n _o filling adhesive with equally uniform refractive index n _s and provides the above optical head device for filling the sawtooth grating.

本発明の光ヘッド装置に用いる位相子は、互いに平行な偏波面を有する異なる２種の波長の直線偏光を、互いに直交させることができる。また、上記位相子に直線偏光の回折機能を付加することにより、位相子に垂直および斜方入射する、２つの直線偏光の光軸を一致させることができる。さらに、回折機能が付加された位相子を、２波長半導体レーザを有する光ヘッド装置に搭載することにより、２つの直線偏光の光軸を一致させることができるため装置中の各光学部品がそれぞれ良好な光学特性を発揮でき、光ディスク上の情報再生時の読み取りエラーおよび光ディスク上への情報記録時の書き込みエラーの極めて少ない安定した信号検出が行える光ヘッド装置を実現できる。また、光検出器が１個でよいため光ヘッド装置の単純化が図れ、組み立て工程数を削減でき、また装置の小型化・軽量化が実現できる。   The phaser used in the optical head device of the present invention can make two kinds of linearly polarized light having different polarization planes parallel to each other and orthogonal to each other. Further, by adding a linearly polarized light diffraction function to the above phaser, the optical axes of the two linearly polarized light incident perpendicularly and obliquely to the phaser can be matched. Furthermore, by mounting a phaser with a diffraction function on an optical head device having a two-wavelength semiconductor laser, the optical axes of the two linearly polarized light can be matched, so that each optical component in the device is excellent. It is possible to realize an optical head device that can exhibit stable optical characteristics and can perform stable signal detection with very few read errors when reproducing information on the optical disk and writing errors when recording information on the optical disk. Further, since only one photodetector is required, the optical head device can be simplified, the number of assembly steps can be reduced, and the device can be reduced in size and weight.

本発明の光ヘッド装置に用いる第１の実施態様の位相子の断面図。1 is a cross-sectional view of a phase shifter according to a first embodiment used in an optical head device of the present invention. 本発明の光ヘッド装置に用いる第２の実施態様の位相子の断面図で、（ａ）一方の直線偏光の光軸が透明基板に垂直入射する様子を示す断面図、（ｂ）他方の直線偏光の光軸が透明基板に斜方入射する様子を示す断面図。It is sectional drawing of the phase shifter of the 2nd embodiment used for the optical head apparatus of this invention, (a) Sectional drawing which shows a mode that the optical axis of one linearly polarized light is perpendicularly incident on a transparent substrate, (b) The other straight line Sectional drawing which shows a mode that the optical axis of polarized light enters diagonally into a transparent substrate. 本発明の第３の実施態様の光ヘッド装置の概念図で、（ａ）２波長半導体レーザの出射点１Ａから直線偏光が出射する様子を示す概念図、（ｂ）２波長半導体レーザの出射点１Ｂから直線偏光が出射する様子を示す概念図。FIG. 4 is a conceptual diagram of an optical head device according to a third embodiment of the present invention, where (a) a conceptual diagram showing a state in which linearly polarized light is emitted from an emission point 1A of a two-wavelength semiconductor laser, and (b) an emission point of the two-wavelength semiconductor laser. The conceptual diagram which shows a mode that linearly polarized light radiate | emits from 1B. 従来の光ヘッド装置の概念図。The conceptual diagram of the conventional optical head apparatus. 本発明の第４の実施態様の光ヘッド装置における光源ユニット（パッケージ）の概念図。The conceptual diagram of the light source unit (package) in the optical head apparatus of the 4th embodiment of this invention.

「第１の実施態様」
本発明の光ヘッド装置に用いる第１の実施態様の位相子１０１は、図１に示すように、有機物薄膜１４を透明基板１１と透明基板１６の間に挟んで、接着剤１５を用いて固定している。透明基板１１および１６としては、ガラスや石英などの光学的等方性媒質を用いることが、透過光に複屈折性などの影響を与えず好ましい。有機物薄膜１４としては、ポリカーボネートなどの有機材料を延伸させることにより延伸方向に光軸の揃った複屈折性膜を用いるのが好ましい。 “First Embodiment”
As shown in FIG. 1, the phase shifter 101 of the first embodiment used in the optical head device of the present invention is fixed using an adhesive 15 with an organic thin film 14 sandwiched between a transparent substrate 11 and a transparent substrate 16. is doing. As the transparent substrates 11 and 16, it is preferable to use an optically isotropic medium such as glass or quartz because the transmitted light is not affected by birefringence or the like. As the organic thin film 14, it is preferable to use a birefringent film having an optical axis aligned in the stretching direction by stretching an organic material such as polycarbonate.

偏波面が互いに平行である、異なる２種の直線偏光の波長の一方をλ₁、他方をλ₂とし、ｍ₁とｍ₂を自然数とする。波長λ₁の光が有機物薄膜１４を透過するとき、２π（ｍ₁−１／２）の位相差が発生し、一方波長λ₂の光が有機物薄膜１４を透過するとき、２πｍ₂の位相差が発生し、２種の直線偏光の偏波面が互いに直交するように有機物薄膜１４のリタデーション値が調整されている。ただし、波長λ₁、λ₂の直線偏光は有機物薄膜１４の進相軸方向（図示せず）に対し偏光方向を４５°傾けて有機物薄膜１４に入射する。 One of the wavelengths of two different types of linearly polarized light whose polarization planes are parallel to each other is λ ₁ , the other is λ _2, and m ₁ and m ₂ are natural numbers. When light having a wavelength λ ₁ is transmitted through the organic thin film 14, a phase difference of 2π (m ₁ −1/2) is generated, whereas when light having a wavelength λ ₂ is transmitted through the organic thin film 14, a phase difference of 2πm ₂ is generated. The retardation value of the organic thin film 14 is adjusted so that the polarization planes of the two types of linearly polarized light are orthogonal to each other. However, the linearly polarized light having the wavelengths λ ₁ and λ ₂ is incident on the organic thin film 14 with the polarization direction inclined by 45 ° with respect to the fast axis direction (not shown) of the organic thin film 14.

例えば、波長λ₁の光をＤＶＤ系光ディスク用の６６０ｎｍ波長帯の光とし、波長λ₂の光をＣＤ系光ディスク用の７９０ｎｍ波長帯の光とした場合を説明する。波長λ₁の光に対し、波長の５／２倍（ｍ₁＝３）となるリタデーション値（位相差は５π）を有するポリカーボネート製の有機物薄膜１４を、入射直線偏光方向に対し進相軸を４５°傾けて配置することにより、波長λ₁の直線偏光は有機物薄膜１４を透過すると、その偏波面を９０°回転する。一方波長λ₂の光に対し、有機物薄膜１４のリタデーション値は、波長の２倍（ｍ₂＝２）に相当（位相差は４π）することになり、有機物薄膜１４を透過する波長λ₂の直線偏光の偏波面は回転しない。すなわち、互いに平行な偏波面は、有機物薄膜１４を透過後直交する。 For example, a case will be described in which light of wavelength λ ₁ is light in the 660 nm wavelength band for DVD optical disks and light of wavelength λ ₂ is light in the 790 nm wavelength band for CD optical disks. The organic thin film 14 made of polycarbonate having a retardation value (phase difference is 5π) which is 5/2 times the wavelength (m ₁ = 3) with respect to the light of the wavelength λ _{1 has} a fast axis with respect to the incident linear polarization direction. by arranging 45 ° tilted, the linearly polarized light of wavelength lambda ₁ is the transmitted through the organic thin film 14, the polarization plane rotates 90 °. To contrast the wavelength lambda ₂ of the light, the retardation value of the thin organic film 14 is 2 times the wavelength corresponding to the (m ₂ = 2) (phase difference 4 [pi]) will be, the wavelength lambda ₂ passing through the organic thin film 14 The plane of polarization of linearly polarized light does not rotate. That is, the planes of polarization parallel to each other are orthogonal after passing through the organic thin film 14.

波長λ₁が８００ｎｍ波長帯であり、波長λ₂が４００ｎｍ波長帯である場合、波長λ₁の光に対し、波長の１／２倍（ｍ₁＝１）となるリタデーション値（位相差はπ）を有する有機物薄膜１４を、入射直線偏光方向に対し進相軸を４５°傾けて配置することにより、波長λ₁の直線偏光は、有機物薄膜１４を透過すると、その偏波面を９０°回転する。一方波長λ₂の光に対し、有機物薄膜１４のリタデーション値は、波長に等しく（ｍ₂＝１）なり（位相差は２π）、有機物薄膜１４を透過する波長λ₂の直線偏光の偏波面は回転しない。すなわち、互いに平行な偏波面は、有機物薄膜１４を透過後直交する。
ここで、自然数ｍ₁およびｍ₂としてはそれぞれ３程度がよく、これより大きくなると、有機物薄膜を複数枚重ねることになり、生産性の点から好ましくない。 When the wavelength λ ₁ is in the 800 nm wavelength band and the wavelength λ ₂ is in the 400 nm wavelength band, the retardation value is ½ times the wavelength (m ₁ = 1) for the light of the wavelength λ ₁ (the phase difference is π ) Is disposed so that the fast axis is inclined by 45 ° with respect to the incident linear polarization direction, the linearly polarized light having the wavelength λ ₁ is rotated by 90 ° when polarized through the organic thin film 14. . On the other hand, the retardation value of the organic thin film 14 is equal to the wavelength (m ₂ = 1) with respect to the light with the wavelength λ ₂ (the phase difference is 2π), and the polarization plane of the linearly polarized light with the wavelength λ ₂ transmitted through the organic thin film 14 is Does not rotate. That is, the planes of polarization parallel to each other are orthogonal after passing through the organic thin film 14.
Here, often each about 3 as natural numbers m ₁ and m _2, becomes larger than this, will be stacked plurality of thin organic film, it is not preferred from the viewpoint of productivity.

複屈折性を有する有機物薄膜１４として、透明基板１６上に塗布した配向膜用の膜に、所望の配向処理を施した後、この膜上に複屈折性材料である液晶モノマーの溶液を塗布し、光重合用の光源光を照射することで重合硬化させた高分子液晶膜を用いることもできる。この場合、接着剤１５を用いることなく位相子を形成できる。   As the organic thin film 14 having birefringence, a film for alignment film applied on the transparent substrate 16 is subjected to a desired alignment treatment, and then a liquid crystal monomer solution as a birefringent material is applied onto the film. Alternatively, a polymer liquid crystal film that has been polymerized and cured by irradiation with light source light for photopolymerization can also be used. In this case, the phaser can be formed without using the adhesive 15.

上記において、有機物薄膜を２枚の透明基板間に固定する場合を説明したが、１枚の透明基板上に固定してもよい。この場合も、接着剤を使用してもよいし直接透明基板に形成してもよい。   Although the case where the organic thin film is fixed between two transparent substrates has been described above, the organic thin film may be fixed on one transparent substrate. In this case as well, an adhesive may be used, or it may be formed directly on the transparent substrate.

接着剤１５の材料としては、アクリル系、エポキシ系、ウレタン系、ポリエステル系、ポリイミド系、ウレア系、メラミン系、フラン系、イソシアネート系、シリコーン系、セルロース系、酢酸ビニル系、塩化ビニル系、ゴム系やそれらの混合系のものを使用できる。接着剤はＵＶ硬化型や熱硬化型であれば作業性がよく好ましいがこれらに限定されない。接着剤は平滑に一定厚さで薄く塗布することが、透過光の波面収差の補正を良好にするために必要である。塗布の方法としては、スピンコートまたはロールコートなどの方法を用いると作業性が優れ、また厚さの制御が容易であり好ましい。   Materials for the adhesive 15 include acrylic, epoxy, urethane, polyester, polyimide, urea, melamine, furan, isocyanate, silicone, cellulose, vinyl acetate, vinyl chloride, rubber A system or a mixture thereof can be used. If the adhesive is UV curable or thermosetting, workability is good, but it is not limited thereto. It is necessary to apply the adhesive smoothly and thinly at a constant thickness in order to satisfactorily correct the wavefront aberration of the transmitted light. As a coating method, it is preferable to use a method such as spin coating or roll coating because the workability is excellent and the thickness can be easily controlled.

前述のように構成された位相子は、偏波面が互いに平行である異なる２種の波長の直線偏光を、偏波面が互いに直交する直線偏光に変換する作用を有し、異なる２種の波長光を偏波面の違いによって分離できる。   The phase shifter configured as described above has a function of converting linearly polarized light having two different wavelengths whose polarization planes are parallel to each other into linearly polarized light whose polarization planes are orthogonal to each other. Can be separated by the difference in the plane of polarization.

「第２の実施態様」
本発明の光ヘッド装置に用いる第２の実施態様の位相子１０２は、図２に示すように、有機物薄膜１４を透明基板１６に接着剤１５を用いて固定した有機物薄膜部と、鋸歯状格子１２からなり光軸調整機能を有する透明基板１１とを、有機物薄膜１４と鋸歯状格子１２が向かい合うように充填接着剤１３を用いて固定してある。鋸歯状格子１２は、入射した２種の波長の直線偏光のいずれか一方を回折させ、他方を回折させない機能を有する。 “Second Embodiment”
As shown in FIG. 2, the phase shifter 102 of the second embodiment used in the optical head device of the present invention includes an organic thin film portion in which an organic thin film 14 is fixed to a transparent substrate 16 using an adhesive 15, and a sawtooth grating. A transparent substrate 11 composed of 12 and having an optical axis adjusting function is fixed using a filling adhesive 13 so that the organic thin film 14 and the sawtooth lattice 12 face each other. The sawtooth grating 12 has a function of diffracting one of the incident linearly polarized light of two wavelengths and not diffracting the other.

透明基板１１および１６、有機物薄膜１４、接着剤１５は第１の実施態様と同様のものが使われる。すなわち、有機物薄膜１４として、偏波面の互いに平行な異なる２種の直線偏光が有機物薄膜１４を、進相軸方向に対し偏光方向を４５°傾けて透過後、偏波面が互いに直交するものを使用する。   The transparent substrates 11 and 16, the organic thin film 14, and the adhesive 15 are the same as those in the first embodiment. That is, as the organic thin film 14, two types of linearly polarized light whose polarization planes are parallel to each other are transmitted through the organic thin film 14 with the polarization direction inclined by 45 ° with respect to the fast axis direction, and then the polarization planes are orthogonal to each other. To do.

ここで、光軸調整機能とは、図２（ｂ）に示すように、透明基板に対し光軸が斜方入射の直線偏光を垂直方向に調整する機能をいう。図２（ａ）は、透明基板に対し光軸が垂直入射する直線偏光の場合である。   Here, as shown in FIG. 2B, the optical axis adjustment function refers to a function of adjusting linearly polarized light whose optical axis is obliquely incident on the transparent substrate in the vertical direction. FIG. 2A shows a case of linearly polarized light whose optical axis is perpendicularly incident on the transparent substrate.

鋸歯状格子１２は、複屈折材料（常光屈折率ｎ_o、異常光屈折率ｎ_e）の例えば高分子液晶からなり、以下の手順で作製される。高分子液晶を、所望の厚さになるように透明基板１１上に塗布する。高分子液晶の異常光屈折率ｎ_e方向の液晶分子の配向ベクトルが、面内の特定方向に揃うように液晶分子を配向させ、光重合用の光源光を照射して重合硬化させたのち、フォトリソグラフィとエッチングの技術により鋸歯状格子を形成する。鋸歯状格子の断面は直角三角形状が好ましいが、図２のように階段状でもよい。階段状の場合、階段のステップ数が多いほど光の利用効率は大きくなり、４段以上のステップを形成すると、７０％以上の１次回折光を利用できて望ましい。 The sawtooth grating 12 is made of, for example, a polymer liquid crystal made of a birefringent material (ordinary refractive index n _o , extraordinary refractive index _ne ), and is manufactured by the following procedure. A polymer liquid crystal is applied on the transparent substrate 11 so as to have a desired thickness. After aligning the liquid crystal molecules so that the alignment vector of the liquid crystal molecules in the extraordinary refractive index _ne direction of the polymer liquid crystal is aligned in a specific direction within the surface, and then polymerizing and curing by irradiating light source light for photopolymerization, A sawtooth grating is formed by photolithography and etching techniques. The cross-section of the sawtooth lattice is preferably a right triangle, but may be stepped as shown in FIG. In the case of a staircase, the light utilization efficiency increases as the number of steps in the staircase increases. It is desirable to form four or more steps because 70% or more of the first-order diffracted light can be used.

充填接着剤１３は屈折率ｎ_sが均一で透明な接着剤であり、例えば屈折率ｎ_sが高分子液晶１２の常光屈折率ｎ_oとほぼ等しくなるように材料を選定する。充填接着剤は、第１の実施態様で述べた接着剤の中から、適宜選択できる。 Filler adhesive 13 has a refractive index n _s is homogeneous and clear adhesive, for example, the refractive index n _s is selected material so as to be substantially equal to the ordinary refractive index n _o of the liquid crystal polymer 12. The filling adhesive can be appropriately selected from the adhesives described in the first embodiment.

上述のように構成された位相子は、偏波面が互いに平行である異なる２種の波長の直線偏光を、偏波面が互いに直交する直線偏光に変換する機能を有し、異なる２種の波長の光を分離するとともに、例えば、波長λ₁の直線偏光には回折格子として作用しないが、波長λ₂の直線偏光に対しては回折格子として作用する。 The phase shifter configured as described above has a function of converting linearly polarized light having two different wavelengths whose polarization planes are parallel to each other into linearly polarized light whose polarization planes are orthogonal to each other, and having two different wavelengths. While separating light, for example, it does not act as a diffraction grating for linearly polarized light of wavelength λ ₁ , but acts as a diffraction grating for linearly polarized light of wavelength λ ₂ .

また、図２において透明基板１１の表面に回折格子を形成することにより、光記録媒体の情報の記録・再生時のトラッキングエラー検出用の３ビ−ムを発生できる。この場合、波長λ₁とλ₂の光のうち一方の光のみ回折するように格子深さに基く位相差がλ₁またはλ₂に対して２πとなるようにすることが好ましい。すなわち、波長λ₁の光のみが回折するときはλ₂に対して２πとなり、波長λ₂の光が回折するときはλ₁に対して２πとなる。 Further, by forming a diffraction grating on the surface of the transparent substrate 11 in FIG. 2, it is possible to generate three beams for detecting a tracking error when recording / reproducing information on an optical recording medium. In this case, it is preferable that the phase difference based on the grating depth is 2π with respect to λ ₁ or λ ₂ so that only one of the lights having wavelengths λ ₁ and λ ₂ is diffracted. That is, the 2π for lambda ₁ when 2π, and the wavelength lambda ₂ of light is diffracted for the lambda ₂ when only the light of wavelength lambda ₁ is diffracted.

本実施態様の別の例として、上述の光軸調整機能の代わりに、位相補正機能を透明基板に付加した位相子とすることもできる。これは、入射直線偏光の波面を制御するものであり、透明基板上に複屈折性の位相補正部を形成すればよい。   As another example of this embodiment, a phase shifter having a phase correction function added to a transparent substrate can be used instead of the above-described optical axis adjustment function. This controls the wavefront of incident linearly polarized light, and a birefringent phase correction unit may be formed on the transparent substrate.

「第３の実施態様」
図３の光ヘッド装置は、２つの発光点１Ａおよび１Ｂからそれぞれ異なる波長の直線偏光を出射するモノリシックな２波長半導体レーザ１、本発明の光ヘッド装置に用いる、第２の実施態様で述べた偏光の光軸調整機能を有する位相子１０２、ビームスプリッタ４、コリメートレンズ５、対物レンズ６、光検出器８から構成され、光ディスク７に記録された情報の再生または光ディスク７に情報の記録を行う。 “Third Embodiment”
The optical head device shown in FIG. 3 is a monolithic two-wavelength semiconductor laser 1 that emits linearly polarized light having different wavelengths from the two light emitting points 1A and 1B, and is used in the optical head device of the present invention. A phase shifter 102 having a polarization optical axis adjustment function, a beam splitter 4, a collimating lens 5, an objective lens 6, and a photodetector 8 are used to reproduce information recorded on the optical disc 7 or record information on the optical disc 7. .

偏光の光軸調整機能を有する位相子１０２に、波長λ₁の直線偏光が入射すると、有機物薄膜部によって、直線偏光の偏波面が９０°回転し、鋸歯状格子１２を構成する高分子液晶に対し常光となる。したがって、鋸歯状格子１２の常光屈折率ｎ_oと充填接着剤１３の屈折率ｎ_sがほぼ等しい（ｎ_o＝ｎ_s）ため、回折せずに直進透過する。 When the linearly polarized light having the wavelength λ ₁ is incident on the phase shifter 102 having the function of adjusting the optical axis of the polarized light, the polarization plane of the linearly polarized light is rotated by 90 ° by the organic thin film portion, and the polymer liquid crystal constituting the sawtooth grating 12 is formed. In contrast, it becomes ordinary light. Therefore, the ordinary refractive index n _o and the refractive index n _s of the filler adhesive 13 of the sawtooth grating 12 are substantially equal (n _o = n _s), straight transmitted without being diffracted.

一方、位相子上の位置であり波長λ₁の直線偏光が入射する点から離れた位置に、斜方入射する波長λ₂の直線偏光は、有機物薄膜部を透過しても直線偏光の偏波面を回転せず、鋸歯状格子１２を構成する高分子液晶に対し異常光となる。したがって、鋸歯状格子１２の異常光屈折率ｎ_eと充填接着剤１３の屈折率ｎ_o（ｎ_s＝ｎ_o）との差（ｎ_e−ｎ_o）、および鋸歯状格子１２の形状に依存する効率を有する＋１次回折光を生じる。波長λ₂の＋１次回折光は、位相子上の波長λ₁の光の出射点と同一点から、波長λ₁の光と光軸を一致させて出射する。 On the other hand, the linearly polarized light having the wavelength λ ₂ that is obliquely incident on the phase shifter and away from the point where the linearly polarized light having the wavelength λ ₁ is incident is the polarization plane of the linearly polarized light even though it is transmitted through the organic thin film portion. Is not rotated and becomes abnormal light with respect to the polymer liquid crystal constituting the sawtooth lattice 12. Therefore, the difference between the refractive index _{n o (n s = n o} ) of the sawtooth extraordinary refractive index of the grating 12 n _e the filling adhesive 13 (n _e -n _o), and depending on the shape of the sawtooth grating 12 + 1st order diffracted light having an efficiency of The + _1st- order diffracted light of wavelength λ ₂ is emitted from the same point as the emission point of the light of wavelength λ ₁ on the phase plate, with the optical axis of the light of wavelength λ ₁ matched.

すなわち、本発明の偏光の光軸調整機能を有する位相子１０２を搭載した光ヘッド装置は、モノリシックな２波長半導体レーザから出射した異なる２種の波長の直線偏光の光軸を一致させることができる。したがって、２つの直線偏光が透過する光学部品が、それぞれの直線偏光に対して良好な光学特性を発揮でき、光ディスク上の情報再生時の読み取りエラーおよび光ディスク上への情報記録時の書き込みエラーの極めて少ない安定した信号検出を行うことができる。
さらに、光検出器は１個でよいため光ヘッド装置の単純化が図れ組み立て工程数を削減でき、また装置の小型化・軽量化が実現できる。 That is, the optical head device equipped with the phase shifter 102 having the function of adjusting the optical axis of polarized light according to the present invention can match the optical axes of linearly polarized light of two different wavelengths emitted from a monolithic two-wavelength semiconductor laser. . Therefore, an optical component that transmits two linearly polarized light can exhibit good optical characteristics with respect to each of the linearly polarized light, and causes extremely high reading errors when reproducing information on the optical disk and writing errors when recording information on the optical disk. Less stable signal detection can be performed.
Furthermore, since only one photodetector is required, the optical head device can be simplified, the number of assembly steps can be reduced, and the device can be reduced in size and weight.

「第４の実施態様」
本発明の第４の実施態様の光ヘッド装置は、２波長半導体レーザ、位相子などを有するパッケージ（光源ユニット）を光ヘッド装置に搭載する。
まず、光源ユニットについて説明する。例えば図２に示す、偏光の光軸調整機能を有する位相子１０２を２波長半導体レーザとともにパッケージに固定して光源ユニットとしてもよい。 “Fourth Embodiment”
In the optical head device according to the fourth embodiment of the present invention, a package (light source unit) having a two-wavelength semiconductor laser, a phase shifter and the like is mounted on the optical head device.
First, the light source unit will be described. For example, a phase shifter 102 having a polarization optical axis adjustment function shown in FIG. 2 may be fixed to a package together with a two-wavelength semiconductor laser to form a light source unit.

図５に示すように、波長がλ₁とλ₂で互いに平行な偏波面を有する２つの直線偏光を発光点位置１Ａと１Ｂから出射する２波長半導体レーザ１が一つの金属製のパッケージ２６内のヒートシンク用金属ブロック２８に固定される。パッケージ２６の２波長半導体レーザ１用の光出射窓ガラス２７によってパッケージ２６は密封されている。２波長半導体レーザ１へ電極２９を通して電流が供給されて、２波長半導体レーザ１発光する。偏光の光軸調整機能を有する位相子１０２は、パッケージ２６の光出射窓ガラス２７の外側に固定され、全体として一つの光源ユニットとなっている。 As shown in FIG. 5, the two-wavelength semiconductor laser 1 that emits two linearly polarized light having wavelengths λ ₁ and λ ₂ and parallel polarization planes from the emission point positions 1A and 1B is contained in one metal package 26. The heat sink metal block 28 is fixed. The package 26 is sealed by a light exit window glass 27 for the two-wavelength semiconductor laser 1 of the package 26. A current is supplied to the two-wavelength semiconductor laser 1 through the electrode 29, and the two-wavelength semiconductor laser 1 emits light. The phase shifter 102 having the function of adjusting the optical axis of polarized light is fixed to the outside of the light exit window glass 27 of the package 26 and constitutes one light source unit as a whole.

また、パッケージに光検出器、電気信号処理回路、アンプ回路などを集積化した光電変換素子を内蔵した光源ユニットとしてもよい。これにより、いっそう小型・集積化を実現できる。   Alternatively, the light source unit may include a photoelectric conversion element in which a photodetector, an electric signal processing circuit, an amplifier circuit, and the like are integrated in a package. Thereby, further miniaturization and integration can be realized.

偏光の光軸調整機能を有する位相子１０２に、光記録媒体での反射による戻り光を光検出器に導くビ−ムスプリッタ用ホログラムをさらに積層して一体化してもよい。これにより、複数の機能が複合化された光源ユニットが実現できるため、部品点数が削減されるとともに小型化できる。   A beam splitter hologram that guides the return light reflected by the optical recording medium to the photodetector may be further laminated and integrated with the phase shifter 102 having a polarization optical axis adjustment function. Accordingly, a light source unit in which a plurality of functions are combined can be realized, so that the number of parts can be reduced and the size can be reduced.

上述のような構成の光源ユニットが搭載された光ヘッド装置において、偏光の光軸調整機能を有する位相子１０２の上表面の同一の発光点位置から、波長λ₁とλ₂の２つの直線偏光を切り替えて出射すると、光源ユニットは２波長光源として使用できるため、従来の単一波長光源と同様に扱うことができ好ましい。 In the optical head device in which the light source unit having the above-described configuration is mounted, two linearly polarized light beams having wavelengths λ ₁ and λ ₂ from the same light emitting point position on the upper surface of the phase shifter 102 having a polarization optical axis adjusting function. Since the light source unit can be used as a two-wavelength light source, it can be handled in the same manner as a conventional single-wavelength light source.

また、光源ユニットが搭載された光ヘッド装置は、２波長半導体レーザや位相子などの光軸合わせの手間が省け光ヘッド装置の組み立て工程が簡略化でき生産性が向上するとともに、光ヘッド装置の小型化・軽量化が実現でき好ましい。   In addition, the optical head device on which the light source unit is mounted eliminates the trouble of optical axis alignment such as a two-wavelength semiconductor laser and a phase shifter, simplifies the assembly process of the optical head device, improves productivity, and improves the productivity of the optical head device. It is preferable because it can be reduced in size and weight.

「例１」
例１は図２に示した第２の実施態様の位相子の具体例である。屈折率が１．５である透明基板１６に、ＤＶＤ系光ディスク用の６６０ｎｍ波長帯の光に対してリタデーション値が１６５０ｎｍであるポリカーボネート製の有機物薄膜１４をアクリル系接着剤１５によって固定した。このリタデーション値は、ｍ₁＝３とした値であり発生する位相差は５πであった。また、ＣＤ系光ディスク用の７９０ｎｍ波長帯の直線偏光に対しては、上記のリタデーション値に対応するのは、ｍ₂＝２とした値であり発生する位相差は４πであった。 "Example 1"
Example 1 is a specific example of the phase shifter of the second embodiment shown in FIG. A polycarbonate organic thin film 14 having a retardation value of 1650 nm with respect to light in a 660 nm wavelength band for a DVD optical disk was fixed to the transparent substrate 16 having a refractive index of 1.5 by an acrylic adhesive 15. This retardation value was a value of m ₁ = 3, and the generated phase difference was 5π. For linearly polarized light in the 790 nm wavelength band for CD optical disks, the retardation value corresponds to the value of m ₂ = 2 and the generated phase difference is 4π.

これらの位相差により、６６０ｎｍ波長帯の直線偏光は偏波面を９０°回転させ、７９０ｎｍ波長帯の直線偏光は偏波面を回転させないため、偏波面が互いに平行である２つの波長帯の光はポリカーボネート製の有機物薄膜１４を透過後、偏波面が直交化された。ただし、６６０ｎｍ波長帯と７９０ｎｍ波長帯の２種の直線偏光を、有機物薄膜１４の進相軸方向に対し偏光方向を４５°傾けて有機物薄膜１４に入射させた。   Because of these phase differences, the linearly polarized light in the 660 nm wavelength band rotates the plane of polarization by 90 °, and the linearly polarized light in the 790 nm wavelength band does not rotate the plane of polarization. After passing through the manufactured organic thin film 14, the plane of polarization was orthogonalized. However, two types of linearly polarized light of a 660 nm wavelength band and a 790 nm wavelength band were incident on the organic thin film 14 with the polarization direction inclined by 45 ° with respect to the fast axis direction of the organic thin film 14.

一方、屈折率が１．５である透明基板１１に、配向膜用のポリイミドを膜状に塗布し、ラビング配向処理を施したのち、この膜上に高分子液晶膜を形成した。高分子液晶の屈折率は、光重合硬化後に異常光屈折率ｎ_eが約１．６、常光屈折率ｎ_oが約１．５となった。位相子に斜方入射するＣＤ系光ディスク用の７９０ｎｍ波長帯の光に対し、所望の回折角度、回折効率が得られるように、３回のフォトリソグラフィとエッチングをそれぞれ交互に繰り返して高分子液晶を段数が８段の鋸歯状格子１２に加工し、偏光の光軸調整機能を有する透明基板を作製した。一方、６６０ｎｍ波長帯の光に対しては、回折効果を有しない。 On the other hand, a polyimide for alignment film was applied in the form of a film on the transparent substrate 11 having a refractive index of 1.5, followed by rubbing alignment treatment, and then a polymer liquid crystal film was formed on the film. Refractive index of the polymer liquid crystal, an extraordinary refractive index after photopolymerization curing n _e of about 1.6, the ordinary refractive index n _o was about 1.5. For the light of 790 nm wavelength band for CD optical disk obliquely incident on the phase shifter, the polymer liquid crystal is obtained by alternately repeating three times of photolithography and etching so as to obtain a desired diffraction angle and diffraction efficiency. A transparent substrate having the function of adjusting the optical axis of polarized light was fabricated by processing into a sawtooth lattice 12 having eight stages. On the other hand, it does not have a diffraction effect for light in the 660 nm wavelength band.

有機物薄膜１４と鋸歯状格子１２が向かい合うように、屈折率ｎ_sが高分子液晶の常光屈折率ｎ_oとほぼ等しいアクリル系の透明な充填接着剤１３を用いて固定し、偏光の光軸調整機能を有する位相子１０２を作製した。 As thin organic film 14 and the sawtooth grating 12 face each other, the refractive index n _s is fixed using a transparent filler adhesive 13 of substantially equal acrylic and ordinary refractive index n _o of the liquid crystal polymer, the optical axis adjustment of the polarization A phase shifter 102 having a function was manufactured.

「例２」
例１で作製された偏光の光軸調整機能を有する位相子１０２を、図３に示すように、光ヘッド装置の２波長半導体レーザ１と対物レンズ６との間に設置した。この光ヘッド装置では、ＤＶＤ系光ディスク用の６６０ｎｍ波長帯の光に対して最適設計された光学系の光軸に、ＣＤ系光ディスク用の７９０ｎｍ波長帯の光の光軸を一致させることができた。そして、ＣＤ系とＤＶＤ系の光ディスクの記録・再生時に共用される受光面積の小さい光検出器８を用いて、ＤＶＤ系およびＣＤ系の光ディスクに対し良好な再生・記録が行えた。 "Example 2"
The phase shifter 102 having the function of adjusting the optical axis of polarized light produced in Example 1 was placed between the two-wavelength semiconductor laser 1 of the optical head device and the objective lens 6 as shown in FIG. In this optical head device, the optical axis of the optical system optimally designed for the light of 660 nm wavelength band for DVD optical disks can be made to coincide with the optical axis of the light of 790 nm wavelength band for CD optical disks. . Then, using the photodetector 8 having a small light receiving area shared during recording / reproduction of CD-type and DVD-type optical discs, good reproduction / recording was possible for DVD-type and CD-type optical discs.

また、光ヘッド装置において、対物レンズ６と光検出器８との間に、偏光の光軸調整機能を有する位相子１０２を設置しても同様の効果が得られる。ＣＤ系光ディスク用の７９０ｎｍ波長帯の光は、コリメートレンズ中や対物レンズ中では最適な光軸を透過することは困難であるが、光検出器の直前で直線偏光の光軸調整を行うことで、ＣＤ系とＤＶＤ系の両光ディスクの記録・再生時に共用される受光面積の小さい光検出器８でも使用できる。   In the optical head device, the same effect can be obtained even if a phase shifter 102 having a function of adjusting the optical axis of polarized light is installed between the objective lens 6 and the photodetector 8. Although it is difficult for light in the 790 nm wavelength band for CD optical discs to pass through the optimal optical axis in a collimating lens or objective lens, it is possible to adjust the optical axis of linearly polarized light just before the photodetector. Also, the photodetector 8 having a small light receiving area shared when recording and reproducing both the CD and DVD optical disks can be used.

１０１：位相子
１０２：偏光の光軸調整機能を有する位相子
１１、１６：透明基板
１２：鋸歯状格子
１３：充填接着剤
１４：有機物薄膜
１５：接着剤
１：２波長半導体レーザ
１Ａ、１Ｂ：発光点
４：ビームスプリッタ
５：コリメートレンズ
６：対物レンズ
７：光ディスク
８Ａ、８Ｂ：光検出器
２６：パッケージ
２７：光出射窓ガラス
２８：ヒートシンク用金属ブロック
２９：電極 DESCRIPTION OF SYMBOLS 101: Phaser 102: Phaser 11, 16 which has the function of adjusting the optical axis of polarized light, 16: Transparent substrate 12: Sawtooth grating 13: Filling adhesive 14: Organic substance thin film 15: Adhesive 1: Two-wavelength semiconductor laser 1A, 1B: Light emitting point 4: Beam splitter 5: Collimating lens 6: Objective lens 7: Optical disk 8A, 8B: Photo detector 26: Package 27: Light exit window glass 28: Metal block 29 for heat sink 29: Electrode

Claims (4)

異なる発光点位置から、それぞれ異なる２種の波長λ_１と波長λ_２（λ_１≠λ_２）で、偏波面が互いに平行な直線偏光を出射する光源と、
前記光源からの光を光記録媒体に集光する対物レンズと、
前記光記録媒体で反射する光を検出する光検出器と、を備えた光ヘッド装置であって、
前記光源と前記対物レンズとの間の光路中、または、前記対物レンズと前記光検出器との間の光路中に、位相子を備え、
前記位相子は、少なくとも１枚の透明基板上に固定された複屈折性を有する有機物薄膜と、回折格子と、を有し、
前記有機物薄膜は、進相軸が、偏波面が互いに平行な２種の直線偏光の偏光方向に対して４５°傾けて入射するように配置され、前記波長λ_１の直線偏光に対しては２π（ｍ_１−１／２）（ｍ_１は自然数）の位相差を、前記波長λ_２の直線偏光に対しては２πｍ_２（ｍ_２は自然数）の位相差を発生させるリタデーション値に調整されて、前記２種の直線偏光の偏波面が互いに直交化され、
前記回折格子は、前記２種の波長の直線偏光のいずれか一方を回折させ、他方を回折させずに前記２種の波長の光の光軸を一致させる光ヘッド装置。 A light source that emits linearly polarized light whose polarization planes are parallel to each other at _two different wavelengths λ ₁ and λ ₂ (λ ₁ ≠ λ ₂ ) from different emission point positions;
An objective lens for condensing light from the light source onto an optical recording medium;
A light detector for detecting light reflected by the optical recording medium, and an optical head device comprising:
In the optical path between the light source and the objective lens, or in the optical path between the objective lens and the photodetector, a phaser is provided,
The phaser includes a birefringent organic thin film fixed on at least one transparent substrate, and a diffraction grating.
The organic thin film is disposed so that a fast axis is inclined by 45 ° with respect to the polarization directions of two types of linearly polarized light whose polarization planes are parallel to each other, and 2π for the linearly polarized light having the wavelength λ ₁ The phase difference of (m ₁ −1/2) (m ₁ is a natural number) is adjusted to a retardation value that generates a phase difference of 2πm ₂ (m ₂ is a natural number) for the linearly polarized light having the wavelength λ _2. The planes of polarization of the two types of linearly polarized light are orthogonal to each other,
The diffraction grating is an optical head device that diffracts one of the linearly polarized light of the two types of wavelengths and matches the optical axes of the light of the two types of wavelengths without diffracting the other. 前記回折格子は、断面が直角三角形状または階段状となる鋸歯状格子であって、常光屈折率ｎ_ｏと異常光屈折率ｎ_ｅを有する複屈折材料からなり、
前記常光屈折率ｎ_ｏと等しく均一な屈折率ｎ_ｓを有する充填接着剤が、前記鋸歯状格子を充填する請求項１に記載の光ヘッド装置。 The diffraction grating is a sawtooth grating in cross-section at right angles triangular or stepped, made of a birefringent material having an ordinary refractive index n _o and extraordinary refractive index n _e,
Filling adhesive with equally uniform refractive index n _s and the ordinary refractive index n _o is the optical head device according to claim 1, filling the sawtooth grating. 前記波長λ_１および前記波長λ_２は、ＤＶＤ用の６６０ｎｍ波長帯とＣＤ用の７９０ｎｍ波長帯との組合せからなる請求項１または請求項２に記載の光ヘッド装置。 3. The optical head device according to claim 1, wherein the wavelength λ ₁ and the wavelength λ ₂ are a combination of a 660 nm wavelength band for DVD and a 790 nm wavelength band for CD. 前記光源は、２波長半導体レーザであり、前記２波長半導体レーザが一つのパッケージ内に固定され、前記パッケージの光出射窓に前記位相子が固定されている請求項１〜３いずれか１項に記載の光ヘッド装置。   The said light source is a 2 wavelength semiconductor laser, The said 2 wavelength semiconductor laser is fixed in one package, The said phaser is fixed to the light emission window of the said package. The optical head device described.

Images