JPH0555937B2 - - Google Patents
Info
- Publication number
- JPH0555937B2 JPH0555937B2 JP57224697A JP22469782A JPH0555937B2 JP H0555937 B2 JPH0555937 B2 JP H0555937B2 JP 57224697 A JP57224697 A JP 57224697A JP 22469782 A JP22469782 A JP 22469782A JP H0555937 B2 JPH0555937 B2 JP H0555937B2
- Authority
- JP
- Japan
- Prior art keywords
- recording medium
- information
- hologram lens
- recording
- light
- 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.)
- Expired - Lifetime
Links
- 230000003287 optical effect Effects 0.000 claims description 15
- 238000000034 method Methods 0.000 description 14
- 230000005540 biological transmission Effects 0.000 description 13
- 238000010586 diagram Methods 0.000 description 11
- 239000000463 material Substances 0.000 description 5
- 230000004075 alteration Effects 0.000 description 4
- GGCZERPQGJTIQP-UHFFFAOYSA-N sodium;9,10-dioxoanthracene-2-sulfonic acid Chemical compound [Na+].C1=CC=C2C(=O)C3=CC(S(=O)(=O)O)=CC=C3C(=O)C2=C1 GGCZERPQGJTIQP-UHFFFAOYSA-N 0.000 description 4
- 241001479434 Agfa Species 0.000 description 2
- WKBOTKDWSSQWDR-UHFFFAOYSA-N Bromine atom Chemical compound [Br] WKBOTKDWSSQWDR-UHFFFAOYSA-N 0.000 description 2
- 108010010803 Gelatin Proteins 0.000 description 2
- GDTBXPJZTBHREO-UHFFFAOYSA-N bromine Substances BrBr GDTBXPJZTBHREO-UHFFFAOYSA-N 0.000 description 2
- 229910052794 bromium Inorganic materials 0.000 description 2
- SOCTUWSJJQCPFX-UHFFFAOYSA-N dichromate(2-) Chemical compound [O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O SOCTUWSJJQCPFX-UHFFFAOYSA-N 0.000 description 2
- 229920000159 gelatin Polymers 0.000 description 2
- 239000008273 gelatin Substances 0.000 description 2
- 235000019322 gelatine Nutrition 0.000 description 2
- 235000011852 gelatine desserts Nutrition 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 230000005415 magnetization Effects 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000002834 transmittance Methods 0.000 description 2
- 229910016629 MnBi Inorganic materials 0.000 description 1
- 150000001786 chalcogen compounds Chemical class 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 230000004304 visual acuity Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
- G11B7/135—Means for guiding the beam from the source to the record carrier or from the record carrier to the detector
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
- G11B7/085—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam into, or out of, its operative position or across tracks, otherwise than during the transducing operation, e.g. for adjustment or preliminary positioning or track change or selection
- G11B7/08547—Arrangements for positioning the light beam only without moving the head, e.g. using static electro-optical elements
Landscapes
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Holo Graphy (AREA)
- Optical Recording Or Reproduction (AREA)
- Optical Head (AREA)
- Automatic Focus Adjustment (AREA)
- Diffracting Gratings Or Hologram Optical Elements (AREA)
Description
【発明の詳細な説明】
本発明は、レーザビームを情報記録媒体上の情
報トラツクに照射し、そこでの反射ビームを受光
素子に導き、その出力を処理して記録情報を読み
取る光学式情報読取装置に関し、更に詳細には、
レーザビームを情報トラツクに集束させる対物レ
ンズとしてホログラムレンズを用いた光学式情報
読取装置に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention provides an optical information reading device that irradiates a laser beam onto an information track on an information recording medium, guides the reflected beam there to a light receiving element, and processes the output to read recorded information. For further details,
The present invention relates to an optical information reading device that uses a hologram lens as an objective lens to focus a laser beam onto an information track.
透過形ホログラムレンズを対物レンズとして用
いた光学式情報読取装置は、既に知られている。
この透過形ホログラムレンズには、オフアクシス
形とインライン形の２種類がある。第１図は前者
のオフアクシス形の透過形ホログラムレンズを得
るに際しての記録方法を示すもので、ガラス等の
支持体にホログラム用感光材料（銀塩、重クロム
酸ゼラチン等）を塗布した乾板HRに、読取に必
要なN.A.（ニユーメリカル・アパーチヤ）をもつ
対物レンズによつてＰ点に集束させられたレーザ
ビームＡと、該レーザビームと同一のレーザ光源
より分岐した記録参照光Ｂとを、同時に照射し干
渉縞を記録している状態を示している。これを現
像した場合の干渉縞のパターン（強度分布）は、
銀塩の場合、黒白の濃淡の形（振幅透過率分布）
として現われ、重クロム酸ゼラチンの場合、屈折
率の変化の形（位相透過率分布）として現われ
る。前者は振幅ホログラムと呼ばれ、後者は位相
ホログラムと呼ばれているが、銀塩も臭素等で漂
泊すれば位相ホログラムとなる。このようにして
得られたオフアクシス形の透過形ホログラムレン
ズでの再生は、第２図に示すように、再生参照光
B′を記録参照光Ｂと逆方向から照射することに
より行う。これにより、P′点に集束する光A′が
得られる。この集束光A′は、再生参照光B′がホ
ログラム面に対して記録参照光Ｂと同一角度で逆
方向に入射していれば、記録時に用いた対物レン
ズの集束光と同一のもの（P′点がＰ点と一致する
もの）が得られる。第３図は、インライン形の透
過形ホログラムの記録方法を示し、第４図は、そ
の再生方法を示している。このインライン形で
は、集束光A′と参照光B′を光軸方向から与えて
再生するため、光学系設定時の調整は容易であ
る。 Optical information reading devices using a transmission hologram lens as an objective lens are already known.
There are two types of transmission hologram lenses: off-axis type and inline type. Figure 1 shows the recording method used to obtain the former off-axis transmission type hologram lens, using a dry plate HR coated with a photosensitive material for holograms (silver salt, dichromate gelatin, etc.) on a support such as glass. At the same time, a laser beam A focused on a point P by an objective lens having the NA (numerical aperture) necessary for reading and a recording reference beam B branched from the same laser light source as the laser beam are simultaneously transmitted. This shows the state in which the beam is irradiated and interference fringes are recorded. The interference fringe pattern (intensity distribution) when this is developed is
In the case of silver salt, the shape of black and white shading (amplitude transmittance distribution)
In the case of dichromate gelatin, it appears as a change in refractive index (phase transmittance distribution). The former is called an amplitude hologram, and the latter is called a phase hologram, but if silver salt is also contaminated with bromine or the like, it becomes a phase hologram. For reproduction with the off-axis transmission type hologram lens obtained in this way, as shown in Figure 2, the reproduction reference beam is
This is done by irradiating the recording reference beam B' from the direction opposite to that of the recording reference beam B. As a result, light A' is obtained which is focused on point P'. This focused light A' is the same as the focused light of the objective lens used during recording (P ' point coincides with point P) is obtained. FIG. 3 shows a method for recording an in-line transmission hologram, and FIG. 4 shows a method for reproducing the same. In this in-line type, since the focused light A' and the reference light B' are applied from the optical axis direction for reproduction, adjustment when setting up the optical system is easy.
オフアクシス形及びインライン形のどちらの透
過形ホログラムを用いても、上述の説明から明ら
かなように、記録に用いた対物レンズと同様な集
束光が得られる。この点に注目して、透過形ホロ
グラムレンズを光学式情報再生装置の対物レンズ
として使用し、光学系の軽量化及び低コスト変を
図るという提案がなされているが、このような構
成の情報再生装置にも、次のような欠点がある。 As is clear from the above explanation, whether an off-axis type or an in-line type transmission hologram is used, focused light similar to that of the objective lens used for recording can be obtained. Focusing on this point, a proposal has been made to use a transmission hologram lens as an objective lens in an optical information reproducing device in order to reduce the weight and cost of the optical system. The device also has the following drawbacks:
(1) インライン形の振幅ホログラムレンズの場
合、中心部分は干渉縞の間隔が大きくなり回折
効率が落ちる。又、体積形ホログラムレンズの
場合、周辺部分はブラツグ回折の条件を満たす
ように効率良く回折するが、中心部分は格子の
間隙が粗いため回折効率が低くなる（第５図及
び第６図参照。但し、第５図中のＳは感光層を
示し、第６図中のｄは感光層Ｓの厚さを示す）。
従つて、これらのホログラムレンズの場合、中
心部分のレーザビームは略０次回折光Ｃとな
り、集光されずに情報記録媒体に向かうことに
なる。ところが、この０次回折光Ｃの反射光
は、ピツトの情報を含んでいないため、フオー
カシングやトラツキングの各制御の基になる位
置ずれ信号（誤差信号）に反映されず、この位
置ずれ信号の検出感度を低下させる。(1) In the case of an in-line amplitude hologram lens, the spacing between interference fringes becomes large in the center, reducing diffraction efficiency. In addition, in the case of a volume hologram lens, the peripheral portion diffracts efficiently to satisfy the conditions of Bragg diffraction, but the central portion has a low diffraction efficiency because the grating gaps are coarse (see FIGS. 5 and 6). However, S in FIG. 5 indicates a photosensitive layer, and d in FIG. 6 indicates the thickness of the photosensitive layer S).
Therefore, in the case of these hologram lenses, the laser beam at the center becomes substantially 0th order diffracted light C, and is directed toward the information recording medium without being focused. However, since the reflected light of this 0th order diffracted light C does not contain pit information, it is not reflected in the positional deviation signal (error signal) that is the basis of each control of focusing and tracking, and the detection sensitivity of this positional deviation signal is decrease.
(2) ホログラム乾板は、ガラス等の支持体に銀塩
等を塗布したものであり、透過形ホログラムレ
ンズの場合、記録時及び再生時における物体光
の集束位置が乾板に関して反対側であるため、
支持体による収差が生じる。(2) A hologram dry plate is a support such as glass coated with silver salt, etc. In the case of a transmission type hologram lens, the focusing position of the object light during recording and reproduction is on the opposite side of the dry plate.
Aberrations occur due to the support.
本発明は、このような欠点に鑑みてなされたも
ので、その目的は、対物レンズ部分において０次
回折光及び収差が生じない光学式情報読取装置で
あつて、駆動系が簡単なものを提供することにあ
る。 The present invention has been made in view of these drawbacks, and its purpose is to provide an optical information reading device that does not generate zero-order diffracted light and aberrations in the objective lens portion, and that has a simple drive system. There is a particular thing.
この目的を達成する本発明の光学式情報読取装
置は、情報記録媒体上の情報トラツクにレーザビ
ームを集束させる対物レンズとして、前記情報記
録媒体に対して傾斜して配置した反射形ホログラ
ムレンズを用い、フオーカシングは、該反射形ホ
ログラムレンズを前記情報記録媒体の表面と直交
するような方向に移動することにより行い、トラ
ツキングは、該反射形ホログラムレンズの前記情
報記録媒体に対する傾斜角を変えて前記情報記録
媒体上のビームスポツトをラジアル方向に移動さ
せることにより行うことを特徴とするものであ
る。 The optical information reading device of the present invention that achieves this object uses a reflective hologram lens arranged obliquely with respect to the information recording medium as an objective lens for focusing a laser beam on an information track on the information recording medium. , focusing is performed by moving the reflective hologram lens in a direction perpendicular to the surface of the information recording medium, and tracking is performed by changing the inclination angle of the reflective hologram lens with respect to the information recording medium. This method is characterized in that it is carried out by moving the beam spot on the recording medium in the radial direction.
以下、図面を参照して本発明の実施例を説明す
る。 Embodiments of the present invention will be described below with reference to the drawings.
第７図は本発明の一実施例を示す構成図で、１
はHe−Neガスレーザ等のレーザ光源、２は入射
ビームと反射ビームを分離するビームスプリツ
タ、３はビームスプリツタ２の透過ビームを受け
る1/4波長板、４は対物レンズとして機能する反
射形ホログラムレンズ、５はデイスク等の光学式
情報記録媒体、６はビームスプリツタ２で分離さ
れた反射ビームを受ける受光素子である。 FIG. 7 is a configuration diagram showing one embodiment of the present invention.
is a laser light source such as a He-Ne gas laser, 2 is a beam splitter that separates the incident beam and reflected beam, 3 is a quarter-wave plate that receives the transmitted beam from beam splitter 2, and 4 is a reflective type that functions as an objective lens. A hologram lens, 5 is an optical information recording medium such as a disk, and 6 is a light receiving element that receives the reflected beam separated by the beam splitter 2.
上記各構成要素の内、反射系ホログラムレンズ
４は、従来この種の装置に使用されていないもの
である。この反射系ホログラムレンズ４における
記録は、第８図に示す如く、乾板HRの感光層Ｓ
側から記録物体光Ａを入射し、透明支持体Ｄ側か
ら記録参照光Ｂを入射させることにより行なれ
る。ここで、記録物体光Ａとしては、読取に必要
なN.A.をもつ対物レンズによつて集束させられ
たレーザビームが用いられる。第９図はこの具体
的な記録装置の一例を示すものである。この装置
は、レーザ光源１１からの出力ビームをビームス
プリツタ１２で透過ビームと反射ビームとに分
け、透過ビームをミラー１３を介して乾板HRの
透明支持体Ｄ側に記録参照光Ｂとして入射させる
と共に、ビームスプリツタ１２での反射ビーム
を、ミラー１４及び上述の所望とN.A.をもつ対
物レンズ１５を介して、乾板HRの感光層Ｓ側に
記録物体光として入射させ、干渉縞を感光層Ｓの
表面に略平行な面として記録させるように構成し
たものである。この装置で記録した乾板HRを現
像処理することにより、反射形ホログラムレンズ
４が得られ、第１０図に示すように、再生参照光
B′を感光層Ｓ側から入射させることで、目的と
する再生物体光A′が生じる。 Among the above components, the reflective hologram lens 4 has not been used in this type of device in the past. The recording in this reflective hologram lens 4 is as shown in FIG.
This can be done by inputting the recording object light A from the side of the transparent support D and inputting the recording reference light B from the side of the transparent support D. Here, as the recording object light A, a laser beam focused by an objective lens having an NA necessary for reading is used. FIG. 9 shows an example of this specific recording apparatus. In this device, an output beam from a laser light source 11 is split into a transmitted beam and a reflected beam by a beam splitter 12, and the transmitted beam is made to enter the transparent support D side of the dry plate HR through a mirror 13 as a recording reference beam B. At the same time, the reflected beam from the beam splitter 12 is made to enter the photosensitive layer S side of the dry plate HR as recording object light via the mirror 14 and the objective lens 15 having the desired NA described above, and the interference fringes are formed on the photosensitive layer S. The structure is such that recording is performed as a surface substantially parallel to the surface of . By developing the dry plate HR recorded with this device, a reflective hologram lens 4 is obtained, and as shown in FIG.
By making B' incident from the photosensitive layer S side, the desired reproduced object beam A' is generated.
ここで、上記装置にて記録したとき反射形ホロ
グラムとなるための条件として次のものを挙げる
ことができる。 Here, the following conditions can be listed as conditions for forming a reflection hologram when recorded with the above apparatus.
() 感光層Ｓが干渉縞の間隔より厚いこと（体
積形ホログラムであること）。() The photosensitive layer S is thicker than the interval between interference fringes (it is a volume hologram).
() 干渉縞の間隔が透過形に比べて狭いため、
感光層Ｓの解像力が十分高いこと。() Because the interval between interference fringes is narrower than that of the transmission type,
The resolution of the photosensitive layer S is sufficiently high.
又、体積形ホログラムかどうかを判定するに
は、
Ｑ＝2πλd／nΔx2
が10以上であるということが一般に知られてい
る。ここで、λは波長、ｄは感光層Ｓの厚さ、ｎ
は屈折率、Δxは干渉縞の間隔である。この干渉
縞の間隔Δxは、
Δx＝λ／2nsin（θ／２）
で示される。尚、θは、感光層Ｓに入射する物体
光と参照光とのなす角である。例えば、Δx≧
0.2μｍであれば、感光層Ｓに必要な解像力は、
5000本／mmとなる。このような解像力をもつ乾板
としては、アグフア8E75HD等がある。アグフア
8E75HDの感光層の厚さは7μｍであり、Ｑ＝300
〜450となり、10以上であるから体積形ホログラ
ムとなる。尚、上記記録装置等で記録し現像した
後、臭素等で漂泊すれば、体積形位相ホログラム
となる。 Furthermore, it is generally known that Q=2πλd/nΔx 2 is 10 or more in order to determine whether or not it is a volume hologram. Here, λ is the wavelength, d is the thickness of the photosensitive layer S, and n
is the refractive index and Δx is the spacing of interference fringes. The interval Δx between the interference fringes is expressed as Δx=λ/2nsin(θ/2). Note that θ is the angle formed by the object light and the reference light incident on the photosensitive layer S. For example, Δx≧
If it is 0.2 μm, the resolving power required for the photosensitive layer S is
5000 lines/mm. Agfa 8E75HD is an example of a dry plate with such resolution. Agfa
The thickness of the photosensitive layer of 8E75HD is 7 μm, and Q = 300
~450, and since it is 10 or more, it is a volume hologram. Incidentally, if it is recorded with the above-mentioned recording device, developed, and then bleached with bromine or the like, it becomes a volume phase hologram.
このようにして形成された反射形ホログラムレ
ンズ４を用いた上記実施例の動作を次に説明す
る。 The operation of the above embodiment using the reflection hologram lens 4 formed in this manner will be described next.
レーザ光源１から出たレーザビームは、ビーム
スプリツタ２を透過し、1/4波長板３に入射し、
ここで、直線偏光から円偏光に変換される。この
変換後のレーザビームは、再生参照光として反射
光ホログラムレンズ４に入射し、再生物体光が記
録媒体５上の情報トラツクに集束する。そして、
そこでの反射ビームは、反射形ホログラムレンズ
４で反射後、1/4波長板３に入射する。ここで、
直線偏光になつたビームは、ビームスプリツタ２
で入射ビームと分離され、受光素子６に入射す
る。この入射光は、ピツトの情報を含んだもので
あり、受光素子６の出力を処理することにより、
記録情報を得ることができると共に、フオーカシ
ングやトラツキング等の光学系制御のための信号
をも得ることができる。この情報読取装置におけ
るフオーカシングは、反射形ホログラムレンズ上
での入射ビームの入射点（域）が変化するので、
光学系全体若しくは反射系ホログラムレンズ４単
体を情報記録媒体５の表面と直交するような方向
に移動すればよい。又、トラツキングは、反射形
ホログラムレンズ４単体をビームスポツトがラジ
アル方向に移動するように傾ければよい。 The laser beam emitted from the laser light source 1 passes through the beam splitter 2, enters the 1/4 wavelength plate 3, and
Here, linearly polarized light is converted into circularly polarized light. The converted laser beam enters the reflected light hologram lens 4 as a reproduction reference beam, and the reproduction object beam is focused on an information track on the recording medium 5. and,
The reflected beam is reflected by a reflective hologram lens 4 and then enters a quarter-wave plate 3. here,
The linearly polarized beam is sent to beam splitter 2.
The light beam is separated from the incident beam and enters the light receiving element 6. This incident light contains pit information, and by processing the output of the light receiving element 6,
Not only can recorded information be obtained, but also signals for optical system control such as focusing and tracking can be obtained. Focusing in this information reading device changes the incident point (area) of the incident beam on the reflective hologram lens.
The entire optical system or the reflective hologram lens 4 alone may be moved in a direction perpendicular to the surface of the information recording medium 5. Further, tracking can be carried out by tilting the reflective hologram lens 4 alone so that the beam spot moves in the radial direction.
ところで、反射形ホログラムレンズ４は、干渉
縞の間隔が狭いため、０次回折光は生じない。
又、記録物体光と参照物体光が同じ方向であるた
め、収差も生じない。このため、フオーカシング
やトラツキングを行うための信号として正確なも
のが得られるため、確実なフオーカシング動作や
トラツキング動作を行える。又、ピツトの情報を
正確に読み取ることができる。 By the way, in the reflective hologram lens 4, since the interval between interference fringes is narrow, zero-order diffracted light is not generated.
Further, since the recording object light and the reference object light are in the same direction, no aberration occurs. Therefore, accurate signals for performing focusing and tracking can be obtained, so that reliable focusing and tracking operations can be performed. In addition, pit information can be read accurately.
尚、本発明は上記実施例に限定されるものでは
ない。例えば、情報トラツクが直線状である記録
媒体の読取装置としても用いることができる。 Note that the present invention is not limited to the above embodiments. For example, it can be used as a reading device for a recording medium in which the information track is linear.
以上説明したように、本発明によれば、対物レ
ンズ部分において０次回折光及び収差が生じない
光学式情報読取装置を実現でき、しかも、トラツ
キングは、反射形ホログラムレンズの情報記録媒
体に対する傾斜角を変えることにより行うため、
反射形ホログラムレンズの支持は単なる回転支持
でよく、ガイドを用い直線変位可能に支持する従
来の場合に比べて、トラツキングの駆動系が簡単
な構成になる。 As explained above, according to the present invention, it is possible to realize an optical information reading device in which zero-order diffraction light and aberration do not occur in the objective lens portion, and in addition, tracking can be performed by adjusting the inclination angle of the reflective hologram lens with respect to the information recording medium. To do this by changing
The reflective hologram lens may be supported by simple rotational support, and the tracking drive system has a simpler structure than the conventional case where a guide is used to support the lens in a linearly displaceable manner.
上記説明では、反射形ホログラムレンズで、光
学式情報記録媒体として既にピツトによる情報の
書込みがなされているデイスク等にレーザ光を集
束させ、その反射光から情報を読み取る場合につ
いて述べたが、情報記録媒体として、追加記録や
書換え可能な材料を有するデイスク等の記録媒体
を用いることによつて、逆に、情報記録媒体に情
報を書き込むことも可能である。即ち、第７図の
構成において、レーザ光源が半導体レーザであれ
ば、光源自体を変調することによつて、又、レー
ザ光源がHe−Ｎのレーザのような気体レーザで
ある場合は、レーザ光源１とビームスプリツタ２
との間にAOM変調器等を入れることによつて、
情報に対応して変調したレーザ光を、1/4波長板
３及び反射形ホログラムレンズ４を介して、追加
記録用の記録媒体や書換え可能な記録媒体に照射
し、該記録媒体の記録層をレーザ光の熱等によつ
て変性又は変形させ、情報を書き込むことができ
る。勿論、使用材料に応じてレーザ光の照射パワ
ー調整せねばならない。この追加記録用の記録媒
体の材料（樹脂等の基体上に形成される層）とし
ては、例えば、Te、In、Te−Ｃ、TeOx（ｘ＝
1.2）やカルコゲン化合物等の如き金属薄膜、金
属微粒子分散系や三層構成が考えられ、この場
合、ピツトはレーザ光による局部加熱によつて形
成される。又、書換え可能な記録媒体に用いられ
る材料としては、例えば、MnBi、GdCo、TbFe
等の光熱磁気材料が考えられ、この場合は、レー
ザ光が保磁力の大きな垂直磁化の微小部分を加熱
することにより磁化の向きを反転させ情報を書込
むことができる。 In the above explanation, we have described the case where a reflective hologram lens is used to focus a laser beam onto a disk, etc., on which information has already been written using pits as an optical information recording medium, and information is read from the reflected light. Conversely, by using a recording medium such as a disk having additionally recordable or rewritable material as the medium, it is also possible to write information on the information recording medium. That is, in the configuration shown in FIG. 7, if the laser light source is a semiconductor laser, the laser light source can be modulated by modulating the light source itself, or if the laser light source is a gas laser such as a He-N laser, the laser light source can be modulated. 1 and beam splitter 2
By inserting an AOM modulator etc. between
A laser beam modulated according to information is irradiated onto a recording medium for additional recording or a rewritable recording medium through a quarter-wave plate 3 and a reflective hologram lens 4, and the recording layer of the recording medium is It is possible to write information by denaturing or deforming it by heat of laser light or the like. Of course, the irradiation power of the laser beam must be adjusted depending on the material used. Examples of the material of the recording medium for this additional recording (layer formed on a base such as resin) include Te, In, Te-C, TeOx (x=
1.2), a metal thin film such as a chalcogen compound, a metal fine particle dispersion system, or a three-layer structure. In this case, the pits are formed by local heating with a laser beam. In addition, examples of materials used for rewritable recording media include MnBi, GdCo, and TbFe.
In this case, a laser beam heats a minute portion of perpendicular magnetization with a large coercive force, thereby reversing the direction of magnetization and writing information.
第１図はオフアクシス形の透過形ホログラムレ
ンズを得る記録方法を示す説明図、第２図は第１
図の方法にて記録された透過形ホログラムレンズ
での再生方法を示す説明図、第３図はインライン
形の透過形ホログラムレンズを得る記録方法を示
す説明図、第４図は第３図の方法にて記録された
透過形ホログラムレンズでの再生方法を示す説明
図、第５図及び第６図は回折効率の説明図、第７
図は本発明の一実施例を示す構成図、第８図は第
７図の実施例中の反射形ホログラムレンズを得る
記録方法を示す説明図、第９図は第８図の記録を
実現する記録装置の一例を示す構成図、第１０図
は第８図の方法にて記録された反射形ホログラム
レンズの再生方法を示す説明図である。
１……レーザ光源、２……ビームスプリツタ、
３……1/4波長板、４……反射形ホログラムレン
ズ、５……情報記録媒体、６……受光素子。
Figure 1 is an explanatory diagram showing the recording method for obtaining an off-axis transmission type hologram lens, and Figure 2 is an explanatory diagram showing the recording method for obtaining an off-axis transmission type hologram lens.
An explanatory diagram showing a reproduction method using a transmission hologram lens recorded by the method shown in the figure, FIG. 3 is an explanatory diagram showing a recording method for obtaining an in-line transmission hologram lens, and FIG. 4 is an explanatory diagram showing the method of FIG. 3. 5 and 6 are explanatory diagrams of diffraction efficiency, and 7.
The figure is a block diagram showing one embodiment of the present invention, FIG. 8 is an explanatory diagram showing a recording method for obtaining the reflective hologram lens in the embodiment of FIG. 7, and FIG. 9 is an illustration of realizing the recording of FIG. 8. FIG. 10 is a block diagram showing an example of a recording device, and is an explanatory diagram showing a method for reproducing a reflective hologram lens recorded by the method shown in FIG. 8. 1... Laser light source, 2... Beam splitter,
3... 1/4 wavelength plate, 4... Reflective hologram lens, 5... Information recording medium, 6... Light receiving element.
Claims (1)
ムを集束させる対物レンズとして、前記情報記録
媒体に対して傾斜して配置した反射形ホログラム
レンズを用い、フオーカシングは、該反射形ホロ
グラムレンズを前記情報記録媒体の表面と直交す
るような方向に移動することにより行い、トラツ
キングは、該反射形ホログラムレンズの前記情報
記録媒体に対する傾斜角を変えて前記情報記録媒
体上のビームスポツトをラジアル方向に移動させ
ることにより行うことを特徴とする光学式情報読
取装置。1. A reflective hologram lens arranged obliquely with respect to the information recording medium is used as an objective lens for focusing a laser beam on an information track on the information recording medium, and focusing is performed by focusing the reflective hologram lens on the information recording medium. The tracking is performed by moving the beam spot on the information recording medium in the radial direction by changing the inclination angle of the reflective hologram lens with respect to the information recording medium. An optical information reading device characterized by:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57224697A JPS59113533A (en) | 1982-12-20 | 1982-12-20 | Optical information reader |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57224697A JPS59113533A (en) | 1982-12-20 | 1982-12-20 | Optical information reader |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59113533A JPS59113533A (en) | 1984-06-30 |
| JPH0555937B2 true JPH0555937B2 (en) | 1993-08-18 |
Family
ID=16817818
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57224697A Granted JPS59113533A (en) | 1982-12-20 | 1982-12-20 | Optical information reader |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59113533A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4784447A (en) * | 1987-03-13 | 1988-11-15 | International Business Machines Corporation | Holographic objective mirror for optical storage |
| JPH07120478B2 (en) * | 1989-12-01 | 1995-12-20 | ニッタン株式会社 | Scattered light smoke detector |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5956236A (en) * | 1982-09-22 | 1984-03-31 | Canon Inc | Optical head |
-
1982
- 1982-12-20 JP JP57224697A patent/JPS59113533A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5956236A (en) * | 1982-09-22 | 1984-03-31 | Canon Inc | Optical head |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59113533A (en) | 1984-06-30 |
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