JPH0461637A - Recorder for optical disk - Google Patents
Recorder for optical diskInfo
- Publication number
- JPH0461637A JPH0461637A JP2168755A JP16875590A JPH0461637A JP H0461637 A JPH0461637 A JP H0461637A JP 2168755 A JP2168755 A JP 2168755A JP 16875590 A JP16875590 A JP 16875590A JP H0461637 A JPH0461637 A JP H0461637A
- Authority
- JP
- Japan
- Prior art keywords
- light
- recording surface
- information recording
- temperature
- wavelength
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 230000003287 optical effect Effects 0.000 title claims abstract description 33
- 238000006243 chemical reaction Methods 0.000 claims description 3
- 238000010438 heat treatment Methods 0.000 abstract description 2
- 230000010287 polarization Effects 0.000 description 7
- 239000000835 fiber Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 239000010410 layer Substances 0.000 description 4
- 239000011521 glass Substances 0.000 description 2
- 230000005415 magnetization Effects 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 229910017112 Fe—C Inorganic materials 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000005466 cherenkov radiation Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 1
- 239000004926 polymethyl methacrylate Substances 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
Landscapes
- Optical Recording Or Reproduction (AREA)
- Optical Head (AREA)
Abstract
Description
【発明の詳細な説明】
技術分野
本発明は、光ディスク（光磁気ディスク、相変化型ディ
スクを含む）の記録装置に関する。DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a recording device for optical disks (including magneto-optical disks and phase change disks).
背景技術
消去可能型光磁気ディスクの書込みは、通常、書込み光
として波長が８３０ｎｍ程度のレーザ光を用い、この書
込み光を１μｍ程度のスポットに集光して光ディスクの
膜面（情報記録面）を照射することにより膜面を熱し、
弱い外部磁界で磁化の向きを反転させることによって記
録ビットを形成している。BACKGROUND ART Writing on an erasable magneto-optical disk usually uses a laser beam with a wavelength of about 830 nm as the writing light, and focuses the writing light on a spot of about 1 μm to write on the film surface (information recording surface) of the optical disk. The film surface is heated by irradiation,
Recording bits are formed by reversing the direction of magnetization using a weak external magnetic field.
ところで、光ディスクにおいて、記録情報の高密度化を
図るには、記録ビットをより小さくする必要がある。そ
のためには、書込み光としてより波長の短い波長のレー
ザ光を用いる必要がある。By the way, in order to increase the density of recorded information in optical discs, it is necessary to make recording bits smaller. For this purpose, it is necessary to use a laser beam with a shorter wavelength as the writing light.
例えば、書込み光の波長を４００ｎｍとすれば、記録ビ
ットのビット長及びビット幅が各々約１／２となり、記
録密度を４倍にすることができる。For example, if the wavelength of the writing light is 400 nm, the bit length and bit width of the recording bits will each be reduced to about 1/2, making it possible to quadruple the recording density.
しかし、現状では、波長が短くなる程レーザ光源の大出
力化が難しく、短波長かつ大出力のレーザ光源の実現が
困難である。However, at present, the shorter the wavelength, the more difficult it is to increase the output of a laser light source, and it is difficult to realize a laser light source with a short wavelength and high output.
発明の概要
［発明の目的］
そこで、本発明は、小出力のより波長の短い光を用いて
高密度の書込みを可能とした光ディスクの記録装置を提
供することを目的とする。Summary of the Invention [Object of the Invention] Therefore, an object of the present invention is to provide an optical disc recording device that enables high-density writing using light with a small output and a shorter wavelength.
［発明の構成］
本発明による光ディスクの記録装置は、第１の光と前記
第１の光よりも波長の長い第２の光とを出射する照射光
学系と、光ディスクの情報記録面上に前記第１の光を所
定径のスポットとして、前記第２の光を前記所定径より
も大なるスポットとしてそれぞれ集光せしめる集光光学
系と、前記第１の光が照射されている情報記録面に対し
て情報の書込みをなす書込み処理系とからなる構成とな
っている。[Structure of the Invention] An optical disk recording device according to the present invention includes an irradiation optical system that emits first light and a second light having a longer wavelength than the first light, and an irradiation optical system that emits the first light and the second light having a longer wavelength than the first light. a condensing optical system that condenses the first light as a spot with a predetermined diameter and the second light as a spot larger than the predetermined diameter; and an information recording surface that is irradiated with the first light. The configuration consists of a writing processing system that writes information to the computer.
［発明の作用コ
本発明による光ディスクの記録装置においては、第１の
光とこれよりも波長の長い第２の光とを用いることとし
、第２の光の集光照射によって情報記録面を記録温度直
前まで昇温し、第１の光の集光照射によって情報記録面
を記録温度以上まで加熱し、情報記録面への情報の書込
みを行なう。[Operation of the Invention] In the optical disc recording device according to the present invention, first light and second light having a longer wavelength are used, and the information recording surface is recorded by condensed irradiation of the second light. The temperature is raised to just below the temperature, and the information recording surface is heated to the recording temperature or higher by condensed irradiation of the first light, and information is written on the information recording surface.
実施例 以下、本発明の実施例を図に基づいて詳細に説明する。Example Hereinafter, embodiments of the present invention will be described in detail based on the drawings.
第１図において、半導体レーザ等の光源１から発せられ
る波長が例えば８３０ｎｍの１次光（光源光）は、集光
レンズ２により集光されてファイバー型光波長変換素子
３に入射する。この光波長変換素子３は、２次の非線形
光学効果を用いたファイバー型Ｓ ＨＧ （Ｓｅｃｏｎ
ｄ Ｈａｒｍｏｎｉｅｓ Ｇｅｎｅｒａｔｏｒ；第２高
調波発生素子）であり、チェレンコフ放射方式の位相整
合を採用している。この方式によれば、はとんど自動的
に位相整合がとれた第２高調波（ＳＲ）の発生が可能で
ある。In FIG. 1, primary light (light source light) having a wavelength of 830 nm, for example, emitted from a light source 1 such as a semiconductor laser is condensed by a condenser lens 2 and enters a fiber type optical wavelength conversion element 3. This optical wavelength conversion element 3 is a fiber type SHG (Second HG) using a second-order nonlinear optical effect.
d Harmonies Generator (second harmonic generation element), which employs Cerenkov radiation type phase matching. According to this method, it is possible to generate a second harmonic (SR) whose phase is almost automatically matched.
このファイバー型５ＨＧ３のコアから出射される１次光
及びファイバー型５ＨＧ３で波長変換されて波長が１次
光の半分（４１５ｎｍ）となったＳＲ光（波長変換光）
は、同一光軸にて例えば円錐台状のアキシコンレンズ４
に入射する。円錐台状アキシコンレンズ４において、１
次光は平行ガラス部４ａを通過し、ＳＲ光は錐状部４ｂ
を通過する。１次光が平行ガラス部４ａを通過すること
によりその厚みによって球面収差が発生し、ＳＲ光が錐
状部４ｂを通過することによって平行光に変換される。The primary light emitted from the core of this fiber type 5HG3 and the SR light (wavelength converted light) whose wavelength has been converted by the fiber type 5HG3 and whose wavelength is half that of the primary light (415 nm).
is, for example, a truncated cone-shaped axicon lens 4 on the same optical axis.
incident on . In the truncated conical axicon lens 4, 1
The secondary light passes through the parallel glass section 4a, and the SR light passes through the conical section 4b.
pass through. When the primary light passes through the parallel glass section 4a, spherical aberration occurs depending on its thickness, and when the SR light passes through the conical section 4b, it is converted into parallel light.
この１次光及びＳＲ先は、偏光面がＰ偏光であることか
らビームスプリッタ５を通過し、λ／４板６で直線偏光
から円偏光に偏光面が変えられて対物レンズ７に入射す
る。This primary light and the SR destination pass through the beam splitter 5 because the polarization plane is P polarization, and the polarization plane is changed from linear polarization to circular polarization by the λ/4 plate 6 and enters the objective lens 7.
対物レンズ７としては、２つの波長（本例では、８３０
ｎｍ、４１５ｎｍ）に対する焦点距離が僅かに異なって
いるものが用いられる。この対物レンズ７の作用により
、第２図に示すように、波長λ２ （λ２−２−８３０
ｎの長い１次光は目標とするビット径の２倍位のスポッ
トとして、波長λ１の短いＳＲ光（λ＋−４１５ｎｍ）
は目標とするビット径のスポットとしてそれぞれ光ディ
スクＤの情報記録面上に集光せしめられる。光ディスク
Ｄの裏面側には、光ディスクＤの情報記録面に情報を書
き込み、又は消去するための直流磁界を発生する電磁石
８が設けられており、その極性は磁界変調回路９によっ
て記録信号に応じて反転せしめられるようになっている
。The objective lens 7 has two wavelengths (in this example, 830
415 nm) with slightly different focal lengths are used. Due to the action of this objective lens 7, the wavelength λ2 (λ2-2-830
The primary light with a long n is a short SR light with a wavelength λ1 (λ+-415 nm) as a spot about twice the target bit diameter.
are respectively focused on the information recording surface of the optical disc D as spots with a target bit diameter. An electromagnet 8 that generates a DC magnetic field for writing or erasing information on the information recording surface of the optical disc D is provided on the back side of the optical disc D, and the polarity of the electromagnet 8 is determined by a magnetic field modulation circuit 9 according to the recording signal. It is designed to be reversed.
光源１から出射される１次光（波長：８３０ｎｍ）のパ
ワーとしては、記録時と再生時とで異なるパワー値がパ
ワー制御回路１０によって設定される。例えば、記録時
の書込みパワーは９ｍＷ。As the power of the primary light (wavelength: 830 nm) emitted from the light source 1, different power values are set by the power control circuit 10 during recording and during reproduction. For example, the write power during recording is 9mW.
再生時の読取りパワーは１〜１．５ｍＷに設定される。The read power during reproduction is set to 1 to 1.5 mW.
再生時において、光ディスクＤからのＳＲ光に基づく反
射光は、対物レンズ７を通過しλ／４板６において円偏
光から直線偏光に偏光面が変えられてビームスプリッタ
５に入射する。ここで、ビームスプリッタ５の入射光は
、λ／４板６を往路及び復路で２度通過したことにより
偏光面がＳ偏光になっているのでビームスプリッタ５で
反射され、さらにダイクロイックミラー１１で反射され
る。このＳＲ光は集光レンズ１２によって光検出器１３
の受光面上に集光される。光検出器１３の出力はそのま
ま読取ＲＦ倍信号して情報再生処理回路１４に供給され
て復調処理等の信号処理が行なわれて再生出力として導
出される。During reproduction, the reflected light based on the SR light from the optical disc D passes through the objective lens 7, and the plane of polarization is changed from circularly polarized light to linearly polarized light by the λ/4 plate 6, and then enters the beam splitter 5. Here, the incident light of the beam splitter 5 passes through the λ/4 plate 6 twice on the outbound and return passes, so that the polarization plane becomes S-polarized light, so it is reflected by the beam splitter 5 and further reflected by the dichroic mirror 11. be done. This SR light is passed through a condensing lens 12 to a photodetector 13.
The light is focused on the light receiving surface. The output of the photodetector 13 is directly converted into a read RF signal and is supplied to the information reproducing processing circuit 14, where signal processing such as demodulation processing is performed, and the signal is derived as a reproduced output.
かかる記録再生装置による情報の記録／再生が行なわれ
る光ディスクとしては、例えば第３図に示すように、−
主面３１ａに所定情報に応じたビット列３２が予め形成
されている再生専用の記録層としてのＰＭＭＡ等からな
る透明基板３１と、Ｇｅ、ＭｇＦ２−ＺｎＳ等の誘電体
多層膜からなり透明基板３１の他主面３１ｂ側から照射
される互いに波長の異なる照射光の一方を反射し他方を
透過する選択的反射膜３３と、Ｔｂ−Ｆｅ−Ｃ。Examples of optical discs on which information is recorded/reproduced by such a recording/reproducing device include -
A transparent substrate 31 made of PMMA or the like serves as a read-only recording layer on which a bit string 32 corresponding to predetermined information is preformed on the main surface 31a, and a transparent substrate 31 made of a dielectric multilayer film of Ge, MgF2-ZnS, etc. Tb-Fe-C and a selective reflection film 33 that reflects one of the irradiated lights having different wavelengths and transmits the other light irradiated from the other principal surface 31b side.
等からなり例えば光磁気方式にて情報の記録及び再生が
可能な記録可能層３４と、保護層３５とからなり、これ
らが順に積層された構成の光ディスクを用い得、かかる
構成の光ディスクにおいて、記録可能層３４が記録／再
生の対象となる。For example, an optical disc may be used that has a structure in which a recordable layer 34 and a protective layer 35 are stacked in this order, and these layers are laminated in order. The possible layer 34 is the target of recording/reproduction.
光磁気方式の記録媒体において、キュリー点記録媒体の
場合、第４図に示すように、媒体の温度を２００℃以上
の保磁力Ｈｃの消失する温度まで熱する。そして、弱い
外部磁界で磁化の方向を反転させて記録ビットを形成す
る。一般に、室温付近の媒体温度を一気に２００℃以上
にまで熱するので、１μｍ程度のスポット径の場合、５
〜１０ｍＷ程度のパワーの書込み光が必要である（なお
、高密度記録の場合には、さらに小さなスポット径とな
る）。In the case of a Curie point recording medium in a magneto-optical recording medium, as shown in FIG. 4, the temperature of the medium is heated to a temperature of 200° C. or higher at which the coercive force Hc disappears. Then, a recording bit is formed by reversing the direction of magnetization using a weak external magnetic field. Generally, the medium temperature near room temperature is heated to over 200°C at once, so in the case of a spot diameter of about 1 μm,
Writing light with a power of about 10 mW is required (in the case of high-density recording, the spot diameter becomes even smaller).
そこで、上述した記録再生装置において、波長λ２の長
い１次光のスポットで１５０℃程度まで昇温し、メイン
ビームである波長λ】の短いＳＨ光で残りの５０〜８０
℃加熱することにより、小出力の短波長で高密度の書込
みができることになる。Therefore, in the above-mentioned recording and reproducing apparatus, the temperature is raised to about 150 degrees Celsius with the long primary light spot with wavelength λ2, and the remaining 50 to 80
By heating at °C, high-density writing can be performed with a short wavelength and low output.
なお、上記実施例においては、記録再生装置に適用した
場合について説明したが、本発明は記録装置そのものに
も適用可能である。In the above embodiments, a case where the present invention is applied to a recording/reproducing device has been described, but the present invention can also be applied to a recording device itself.
発明の詳細
な説明したように、本発明による光ディスクの記録装置
においては、第１の光とこれよりも波長の長い第２の光
とを用いることとし、第２の光の集光照射によって情報
記録面を記録温度直前まで昇温し、第１の光の集光照射
によって情報記録面を記録温度以上まで加熱し、情報記
録面への情報の書込みを行なう構成となっているので、
小出力のより波長の短い光で高密度の書込みが可能とな
る。As described in detail, the optical disc recording device according to the present invention uses a first light and a second light having a longer wavelength, and collects information by condensing the second light. Since the configuration is such that the temperature of the recording surface is raised to just before the recording temperature, and the information recording surface is heated to the recording temperature or higher by condensed irradiation of the first light, information is written on the information recording surface.
High-density writing is possible with low-output, shorter-wavelength light.
第１図は本発明の一実施例を示す構成図、第２図は波長
λ１の短いＳＨ光と波長λ２の長い１次光との集光状態
を示す図、第３図は光ディスクの構成の一例を示す断面
図、第４図は光磁気ディスクにおける媒体温度と保磁力
との関係を示す特性図である。
主要部分の符号の説明
３・・・・・・ファイバー型５ＨＧ
４・・・・・・円錐台状アキシコンレンズ５・・・・・
・ビームスプリッタ
７・・・・・・対物レンズ
１１・・・・・・ダイクロイックミラー１３・・・・・
・光検出器FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing a convergence state of short SH light with a wavelength λ1 and long primary light with a wavelength λ2, and FIG. 3 is a diagram showing the configuration of an optical disc. FIG. 4, which is a sectional view showing an example, is a characteristic diagram showing the relationship between medium temperature and coercive force in a magneto-optical disk. Explanation of symbols of main parts 3... Fiber type 5HG 4... Frustoconical axicon lens 5...
・Beam splitter 7...Objective lens 11...Dichroic mirror 13...
・Photodetector
Claims (2)
光とを出射する照射光学系と、 光ディスクの情報記録面上に前記第１の光を所定径のス
ポットとして、前記第２の光を前記所定径よりも大なる
スポットとしてそれぞれ集光せしめる集光光学系と、 前記第１の光が照射されている情報記録面に対して情報
の書込みをなす書込み処理系とからなることを特徴とす
る光ディスクの記録装置。(1) an irradiation optical system that emits a first light and a second light having a longer wavelength than the first light; and a spot having a predetermined diameter on the information recording surface of an optical disc, a condensing optical system that condenses the second light into a spot larger than the predetermined diameter; and a writing processing system that writes information on the information recording surface irradiated with the first light. An optical disc recording device comprising:
行光の２次光として前記光源光と同一光軸にて出射する
ファイバー型光波長変換素子を有し、前記２次光を前記
第１の光として、前記光源光を前記第２の光として用い
ることを特徴とする請求項１記載の光ディスクの記録装
置。(2) The irradiation optical system includes a fiber-type optical wavelength conversion element that converts the wavelength of the light source light and emits it as parallel secondary light along the same optical axis as the light source light, and converts the secondary light into 2. The optical disc recording apparatus according to claim 1, wherein the light source light is used as the second light as the first light.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2168755A JPH0461637A (en) | 1990-06-27 | 1990-06-27 | Recorder for optical disk |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2168755A JPH0461637A (en) | 1990-06-27 | 1990-06-27 | Recorder for optical disk |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0461637A true JPH0461637A (en) | 1992-02-27 |
Family
ID=15873834
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2168755A Pending JPH0461637A (en) | 1990-06-27 | 1990-06-27 | Recorder for optical disk |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0461637A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2004019333A1 (en) * | 2002-08-21 | 2004-03-04 | Matsushita Electric Industrial Co., Ltd. | Optical information processing device and recording medium |
-
1990
- 1990-06-27 JP JP2168755A patent/JPH0461637A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2004019333A1 (en) * | 2002-08-21 | 2004-03-04 | Matsushita Electric Industrial Co., Ltd. | Optical information processing device and recording medium |
| US7139233B2 (en) | 2002-08-21 | 2006-11-21 | Matsushita Electric Industrial Co., Ltd. | Optical information processing device and recording medium |
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