JPH0799589B2 - Optical pickup device - Google Patents
Optical pickup deviceInfo
- Publication number
- JPH0799589B2 JPH0799589B2 JP59094001A JP9400184A JPH0799589B2 JP H0799589 B2 JPH0799589 B2 JP H0799589B2 JP 59094001 A JP59094001 A JP 59094001A JP 9400184 A JP9400184 A JP 9400184A JP H0799589 B2 JPH0799589 B2 JP H0799589B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- amount
- optical
- recording medium
- semiconductor laser
- 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
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
- G11B7/125—Optical beam sources therefor, e.g. laser control circuitry specially adapted for optical storage devices; Modulators, e.g. means for controlling the size or intensity of optical spots or optical traces
- G11B7/126—Circuits, methods or arrangements for laser control or stabilisation
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
- H01S5/068—Stabilisation of laser output parameters
- H01S5/06817—Noise reduction
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
- H01S5/068—Stabilisation of laser output parameters
- H01S5/0683—Stabilisation of laser output parameters by monitoring the optical output parameters
- H01S5/0687—Stabilising the frequency of the laser
Landscapes
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Mounting And Adjusting Of Optical Elements (AREA)
- Optical Head (AREA)
Description
【発明の詳細な説明】 (産業上の利用分野) 本発明は半導体レーザを用い、光学的に情報の書込みや
再生を行なう情報記録装置に適した光ピックアップ装置
に関する。Description: TECHNICAL FIELD The present invention relates to an optical pickup device suitable for an information recording device that optically writes and reproduces information by using a semiconductor laser.
(従来技術とその問題点) 高密度の記録装置として、金属薄膜や有機薄膜の記録媒
体上へ微小スポットを集光して記録や読出しを行なう光
記録装置が実用化されている。(Prior Art and Its Problems) As a high-density recording device, an optical recording device for recording and reading by converging a minute spot on a recording medium of a metal thin film or an organic thin film has been put into practical use.
このような光記録において用いられる光ピックアップの
基本構成を第1図に示す。半導体レーザ1の出射光をレ
ンズ2によりコリメート光とし、偏光ビームスプリッタ
3と1/4波長板4を通過せしめレンズ5により記録媒体
6にスポットとして集光する。媒体よりの反射光はレン
ズ5,1/4波長板4を再び通過するが、1/4波長板を2回通
過して偏光方向が90゜回転しているため偏光ビームスプ
リッタ3で反射して検出器7に入射する。記録媒体への
書込時は媒体上で10〜15mW程度の光強度となるように、
また再生時には0.5〜3mW程度の光強度となるように記録
媒体の特性に合わせて半導体レーザの出力を調節する。The basic structure of an optical pickup used in such optical recording is shown in FIG. The light emitted from the semiconductor laser 1 is made into collimated light by the lens 2, passed through the polarization beam splitter 3 and the 1/4 wavelength plate 4, and condensed by the lens 5 as a spot on the recording medium 6. The light reflected from the medium passes through the lens 5 and the 1/4 wavelength plate 4 again, but passes through the 1/4 wavelength plate twice and is reflected by the polarization beam splitter 3 because the polarization direction is rotated by 90 °. It is incident on the detector 7. When writing on the recording medium, make the light intensity of about 10 to 15 mW on the medium,
Also, the output of the semiconductor laser is adjusted according to the characteristics of the recording medium so that the light intensity is about 0.5 to 3 mW during reproduction.
この構成では偏光ビームスプリッタと1/4波長板により
半導体レーザへ媒体からの反射光が戻らないようにして
いる。しかし、一般に記録媒体はアクリルやポリカーボ
ネイトなどの高分子樹脂で表面を覆っており、このよう
な高分子樹脂は製造時の応力などによりわずかな複屈折
性を持つ。そのため反射光の分離が十分でなくなり、半
導体レーザにわずかな戻り光が生じる。このレーザへの
戻り光は出力光の雑音を増加させる。In this configuration, the polarization beam splitter and the quarter-wave plate prevent the reflected light from the medium from returning to the semiconductor laser. However, the surface of the recording medium is generally covered with a polymer resin such as acrylic or polycarbonate, and such a polymer resin has a slight birefringence due to stress during manufacturing. Therefore, the reflected light is not sufficiently separated, and a slight return light is generated in the semiconductor laser. The return light to this laser increases the noise of the output light.
半導体レーザの雑音特性の戻り光量依存性の例を第2図
に示す。戻り光量はレーザの前端面出射全光量に対し
て、レーザ端面へ戻る光量の割合を表わす。S/Nは帯域
幅10KHzでの値である。画像情報などアナログの信号の
再生にはS/N95dB以上が必要である。FIG. 2 shows an example of the returning light amount dependency of the noise characteristics of the semiconductor laser. The amount of returned light represents the ratio of the amount of light returned to the laser end face to the total amount of light emitted from the front facet of the laser. S / N is the value at a bandwidth of 10 KHz. S / N of 95 dB or higher is required to reproduce analog signals such as image information.
第1図の構成においては半導体レーザへの戻り光量は0.
1〜1%程度であり、アナログ信号再生時に十分なS/Nを
確保するのは難しい。In the configuration shown in FIG. 1, the amount of light returned to the semiconductor laser is 0.
It is about 1 to 1%, and it is difficult to secure a sufficient S / N during analog signal reproduction.
半導体レーザへの戻り光量を減らす方法として、レンズ
2と偏光ビームスプリッタ3の間に光減衰量が固定の光
減衰器を挿入することが考えられる。例えば透過率1/10
の減衰器により戻り光量は1/100となり0.01%以下であ
り第2図よりS/N105dBとなる。ただし、このとき半導体
レーザは10倍の出力が必要であり、情報の書込み時に10
0mW以上の出力が要求されることになり、このような高
出力で信頼性の高いレーザの実現は難しい。As a method of reducing the amount of light returning to the semiconductor laser, it is conceivable to insert an optical attenuator having a fixed optical attenuation amount between the lens 2 and the polarization beam splitter 3. For example, transmittance 1/10
With the attenuator, the amount of returned light is 1/100, which is 0.01% or less, which is S / N 105 dB from Fig. 2. However, at this time, the semiconductor laser needs to output 10 times more power,
Since an output of 0 mW or more is required, it is difficult to realize such a high output and highly reliable laser.
(発明の目的) 本発明の目的は、このような従来技術の欠点を除去せし
めて、雑音特性の良好な記録・再生用の光ピックアップ
装置を提供することにある。(Object of the Invention) An object of the present invention is to eliminate the drawbacks of the prior art and provide an optical pickup device for recording / reproducing with good noise characteristics.
(発明の構成) 本発明は、半導体レーザから成る光源と、第1の光検出
器と、前記光源からの光を絞り込んで記録媒体に導き、
当該記録媒体から反射光を前記第1の光検出器に導く光
学系とを備えている光ピックアップ装置において、前記
光学系中に設置され、前記記録媒体への記録動作時に
は、透過率を上げて透過光量を増大させ、再生動作時に
は、透過率を下げて前記光源への戻り光量を減少させる
可変光減衰素子と、当該可変光減衰素子の透過光量を検
出する第2の光検出器と、前記透過光量が所定の値とな
るように前記半導体レーザの出力を制御する制御回路と
を具備することを特徴としている。(Structure of the Invention) According to the present invention, a light source including a semiconductor laser, a first photodetector, and light from the light source are narrowed down and guided to a recording medium,
An optical pickup device including an optical system that guides reflected light from the recording medium to the first photodetector, the optical pickup device being installed in the optical system and increasing a transmittance during a recording operation on the recording medium. A variable light attenuating element that increases the amount of transmitted light and reduces the amount of light returning to the light source during reproduction operation; a second photodetector that detects the amount of transmitted light of the variable light attenuating element; And a control circuit for controlling the output of the semiconductor laser so that the amount of transmitted light becomes a predetermined value.
(構成の詳細な説明) 記録媒体への記録・再生を行なう光ピックアップ装置に
おいて、媒体への記録動作時には半導体レーザは方形波
で駆動されるため雑音に対する許容量が大きく、光出力
のS/Nは60〜70dB程度で十分である。再生動作時の必要
なS/Nは再生信号がディジタルであるか、アナログであ
るかはよって異なる。ディジタル信号は書込動作時と同
程度のS/Nで十分であるが、アナログ信号の再生動作時
には高S/Nが必要となる。(Detailed description of configuration) In an optical pickup device for recording / reproducing on / from a recording medium, since the semiconductor laser is driven by a square wave during recording operation on the medium, the noise tolerance is large and the S / N of optical output is large. Is about 60 to 70 dB. The required S / N at the time of reproduction operation differs depending on whether the reproduction signal is digital or analog. Although the S / N ratio of the digital signal is the same as that of the writing operation, a high S / N ratio is required in the reproducing operation of the analog signal.
再生動作時のS/Nを上げる方法として、本発明では第1
図のコリメート用レンズ2と偏光ビームスプリッタ3の
間に透過率が変化する可変光減衰素子を挿入している。
記録動作時には透過率を上げ、再生動作時には透過率を
下げて戻り光量を減らせばよい。According to the present invention, the first method is to increase the S / N ratio during the reproducing operation.
A variable optical attenuator whose transmittance changes is inserted between the collimating lens 2 and the polarization beam splitter 3 in the figure.
The amount of return light may be reduced by increasing the transmittance during the recording operation and decreasing the transmittance during the reproducing operation.
可変光減衰素子としては第3図に示すように、光路11に
光学フィルタ12を出し入れするのが最も簡単な構成であ
る。As the variable optical attenuating element, as shown in FIG. 3, the simplest structure is to put an optical filter 12 in and out of the optical path 11.
第4図は光路11中に1/2波長板13を挿入し、波長板を回
転させて光量を変化させる方法である。半導体レーザの
出射光は一般に直線偏光であり、光軸と1/2波長板の設
定角度により偏光方向を任意の角度回転することができ
る。偏光方向が回転すると、次の偏光ビームスプリッタ
で回転以前の偏光方向の成分のみが透過するため、透過
光量は減衰することになる。1/2波長板は戻り光に対し
ても同様に偏光回転を与える。半導体レーザは出射光と
直交する偏光の影響を受けにくく回転以前の偏光方向の
成分のみの影響を受けるため、戻り光量は減ることにな
る。減衰素子としての動作を確実にするため、コリメー
ト用のレンズと1/2波長板の間に一方向の偏光成分のみ
を透過する検光子を挿入してもよい。この方法において
透過率を10%とするには偏光方向を84゜回転すればよ
く、このためには1/2波長板を42゜回転すればよい。記
録動作時には回転角を0゜、再生動作時には回転角42゜
となるよう1/2波長板を設定することになる。FIG. 4 shows a method in which the half-wave plate 13 is inserted in the optical path 11 and the wavelength plate is rotated to change the light amount. The emitted light of the semiconductor laser is generally linearly polarized light, and the polarization direction can be rotated by an arbitrary angle depending on the set angle between the optical axis and the half-wave plate. When the polarization direction is rotated, only the component of the polarization direction before rotation is transmitted by the next polarization beam splitter, so that the transmitted light amount is attenuated. The 1/2 wave plate similarly imparts polarization rotation to the returning light. The semiconductor laser is less likely to be affected by the polarization orthogonal to the emitted light, and is affected only by the component in the polarization direction before rotation, so that the amount of returned light is reduced. In order to ensure the operation as the attenuator, an analyzer that transmits only the polarized component in one direction may be inserted between the collimating lens and the half-wave plate. In this method, in order to obtain a transmittance of 10%, the polarization direction should be rotated by 84 °, and for this purpose, the 1/2 wavelength plate should be rotated by 42 °. The half-wave plate is set so that the rotation angle is 0 ° during the recording operation and the rotation angle is 42 ° during the reproducing operation.
1/2波長板の回転動作と同様の働きをTN型の液晶素子に
よっても実現できる。TN型の液晶素子14は第5図に示す
ように電圧を加えないときは透過光が偏光回転を示し、
電圧を加えると偏光回転を示さなくなる。よって可変光
減衰素子として用いることができる。The same operation as the rotation operation of the half-wave plate can be realized by the TN type liquid crystal element. As shown in FIG. 5, the TN type liquid crystal element 14 shows that transmitted light shows polarization rotation when no voltage is applied,
When the voltage is applied, it does not show polarization rotation. Therefore, it can be used as a variable optical attenuator.
ここで問題となるのは、これらの可変減衰素子の透過率
を変化させるに必要なスイッチング時間が長いことであ
る。例えばTN型液晶素子においては、10〜30ミリ秒のス
イッチング時間を要する。The problem here is that the switching time required to change the transmittance of these variable attenuation elements is long. For example, a TN type liquid crystal element requires a switching time of 10 to 30 milliseconds.
スイッチング時間の速いものとして、ニオブ酸リチウム
などの電気光学効果を示す結晶を用いて偏光回転を起す
こともできるが、90゜近い偏光回転を起すには数百ボル
ト以上の高電圧を必要とするため実用的でない。As a fast switching time, it is possible to cause polarization rotation by using a crystal that exhibits an electro-optical effect such as lithium niobate, but a high voltage of several hundred volts or more is required to cause polarization rotation near 90 °. Therefore, it is not practical.
スイッチング時間が長いことで問題となるのは、スイッ
チング動作中に記録媒体上で光パワーが不安定となるこ
とと、透過率増加による戻り光量の増大でS/Nが低下す
ることである。これらの問題は以下のように解決され
る。The problem with the long switching time is that the optical power becomes unstable on the recording medium during the switching operation and the S / N decreases due to the increase in the amount of returning light due to the increase in the transmittance. These problems are solved as follows.
光パワーを安定化するためには、可変減衰素子の透過光
量を検出して、常に記録媒体上で一定の光量となるよう
に半導体レーザの出力を制御すればよい。In order to stabilize the optical power, the amount of light transmitted through the variable attenuator may be detected and the output of the semiconductor laser may be controlled so that the amount of light is always constant on the recording medium.
可変光減衰素子の透過率とレーザ出力の変化および記録
媒体面上光パワーの時間変化を第6図に示す。第6図B
のように透過率はあるスイッチング時間幅をもって変化
する。スイッチング動作中も記録媒体面上で一定の光パ
ワーとなるようにレーザ出力を第6図Cのように透過率
の変化に合わせて制御する。この結果、記録媒体面上で
は第6図Aのようにスイッチング動作時にも再生動作時
と同様の光パワーが得られる。FIG. 6 shows changes in the transmittance and laser output of the variable optical attenuator and changes in the optical power on the surface of the recording medium with time. Fig. 6B
As described above, the transmittance changes with a certain switching time width. The laser output is controlled according to the change in transmittance as shown in FIG. 6C so that the optical power is constant on the surface of the recording medium even during the switching operation. As a result, on the surface of the recording medium, the same optical power as in the reproducing operation can be obtained during the switching operation as shown in FIG. 6A.
光記録は一般にディスク形状の記録媒体を回転させて同
心円またはらせん状のトラックに、記録・再生を行な
う。回転数は毎分600〜1800回転である。再生動作から
記録動作を実施するためには所望のトラック位置まで、
光ピックアップを移動してあらかじめディスクに記録し
てあるトラック位置を示すアドレス増俸を確認すること
になる。アドレス情報の確認にはディスクが一回転以上
回転する必要があり、毎分1800回転のディスクにおいて
も33ミリ秒以上を要する。アドレス情報をディジタルで
記録しておけば高S/Nを必要としないため、アドレス情
報の確認動作の間にスイッチングを終了することが可能
である。記録動作から再生動作へのスイッチング動作時
には1回転分はS/Nの悪い再生が行なわれるが、アナロ
グの画像再生などでは最初の一画面のみが低S/Nとなる
だけなので、毎秒30画面で再生される画像の目視による
記録情報の確認等では支障はない。In optical recording, generally, a disk-shaped recording medium is rotated to perform recording / reproduction on a concentric circle or spiral track. The rotation speed is 600 to 1800 rpm. In order to perform the recording operation from the playback operation, to the desired track position,
By moving the optical pickup, the address increase indicating the track position previously recorded on the disc is confirmed. It is necessary to rotate the disc once or more to confirm the address information, and it takes 33 milliseconds or more even for a disc of 1800 revolutions per minute. Since the high S / N is not required if the address information is recorded digitally, it is possible to complete the switching during the confirmation operation of the address information. During the switching operation from the recording operation to the playback operation, the S / N is reproduced poorly for one rotation, but in the case of analog image reproduction, only the first one screen has a low S / N, so 30 screens per second. There is no problem in visually checking the recorded information of the reproduced image.
(実施例) 可変光減衰素子の透過率を検出する検出器として、第1
図の信号検出用の光検出器7を共用し、記録媒体からの
反射光量から透過率を得ることができる。ただし、この
方法では記録媒体上での記録の有無により反射率が異な
るため正確な透過率を得ることは難しい。(Example) As a detector for detecting the transmittance of a variable optical attenuator,
The photodetector 7 for signal detection in the figure can be shared, and the transmittance can be obtained from the amount of reflected light from the recording medium. However, with this method, it is difficult to obtain an accurate transmittance because the reflectance differs depending on the presence or absence of recording on the recording medium.
第5図に示すTN型液晶素子のように偏光回転を用いたも
のは偏光ビームスプリッタ3で減衰光量分を反射させて
いる。よってこの反射光を第7図に示すように光検出器
15で検出することで可変光減衰素子の透過率が得られ
る。この透過率より制御回路16により半導体レーザの駆
動電流を制御して記録媒体上で一定の光パワーを得る。In the TN type liquid crystal device shown in FIG. 5, which uses polarization rotation, the polarization beam splitter 3 reflects the attenuated light amount. Therefore, this reflected light is converted into a photodetector as shown in FIG.
By detecting at 15, the transmittance of the variable optical attenuator can be obtained. Based on this transmittance, the control circuit 16 controls the driving current of the semiconductor laser to obtain a constant optical power on the recording medium.
第8図に制御回路16の一構成例を示す。半導体レーザ1
のパッケージ内にある光検出器の出力と光検出器15の出
力を比較器17で比較してディスク面上パワーを求める。
17の出力と基準信号21を比較器18で比べて誤差信号を得
て駆動回路19でフィードバック制御を行なう。FIG. 8 shows a configuration example of the control circuit 16. Semiconductor laser 1
The output of the photodetector and the output of the photodetector 15 in the package (1) are compared by the comparator 17 to obtain the power on the disk surface.
The output of 17 and the reference signal 21 are compared by the comparator 18 to obtain an error signal, and the drive circuit 19 performs feedback control.
以上の動作は再生およびスイッチング動作時に働く。記
録動作時にはスイッチ20を切換えて記録信号22により半
導体レーザの駆動を行なう。The above operation works during the reproduction and switching operations. During the recording operation, the switch 20 is switched to drive the semiconductor laser by the recording signal 22.
(発明の効果) 以上説明したように、本発明により再生動作時のS/Nが
良好な、記録・再生用光ピックアップ装置を得ることが
できる。(Effects of the Invention) As described above, according to the present invention, it is possible to obtain the recording / reproducing optical pickup device having a good S / N ratio during the reproducing operation.
第1図は光ピックアップの基本構成を示す図、第2図は
半導体レーザの雑音の戻り光量依存性の図、第3図〜第
5図は可変光減衰素子の構成例を示す図、第6図は本発
明の動作を示す図、第7図は本発明の一実施例を示す
図、第8図は制御回路の一構成例を示す図である。 図において、 1……半導体レーザ、2……コリメート用レンズ、3…
…偏光ビームスプリッタ、4……1/4波長板、5……レ
ンズ、6……記録媒体、7……光検出器、11……光路、
12……光学フィルタ、13……1/2波長板、14……TN型液
晶素子、15……光検出器、16……レーザ出力制御回路、
17,18……比較器、19……駆動回路、20……スイッチで
ある。FIG. 1 is a diagram showing the basic configuration of an optical pickup, FIG. 2 is a diagram showing the return light amount dependency of noise of a semiconductor laser, FIGS. 3 to 5 are diagrams showing a configuration example of a variable optical attenuating element, and FIG. FIG. 7 is a diagram showing the operation of the present invention, FIG. 7 is a diagram showing an embodiment of the present invention, and FIG. 8 is a diagram showing a configuration example of a control circuit. In the figure, 1 ... Semiconductor laser, 2 ... Collimating lens, 3 ...
… Polarizing beam splitter, 4 …… 1/4 wavelength plate, 5 …… Lens, 6 …… Recording medium, 7 …… Photodetector, 11 …… Optical path,
12 …… Optical filter, 13 …… 1/2 wave plate, 14 …… TN type liquid crystal element, 15 …… Photodetector, 16 …… Laser output control circuit,
17,18 …… Comparator, 19 …… Drive circuit, 20 …… Switch.
Claims (1)
出器と、前記光源からの光を絞り込んで記録媒体に導
き、当該記録媒体から反射光を前記第1の光検出器に導
く光学系とを備えている光ピックアップ装置において、
前記光学系中に設置され、前記記録媒体への記録動作時
には、透過率を上げて透過光量を増大させ、再生動作時
には、透過率を下げて前記光源への戻り光量を減少させ
る可変光減衰素子と、当該可変光減衰素子の透過光量を
検出する第2の光検出器と、前記透過光量が所定の値と
なるように前記半導体レーザの出力を制御する制御回路
とを具備することを特徴とする光ピックアップ装置。1. A light source comprising a semiconductor laser, a first photodetector, and an optical for narrowing down the light from the light source and guiding it to a recording medium, and guiding reflected light from the recording medium to the first photodetector. In an optical pickup device including a system,
A variable optical attenuator installed in the optical system for increasing the transmittance to increase the amount of transmitted light during a recording operation on the recording medium and decreasing the transmittance to decrease the amount of light returning to the light source during a reproducing operation. And a second photodetector for detecting the amount of transmitted light of the variable optical attenuator, and a control circuit for controlling the output of the semiconductor laser so that the amount of transmitted light becomes a predetermined value. Optical pickup device.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP59094001A JPH0799589B2 (en) | 1984-05-11 | 1984-05-11 | Optical pickup device |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP59094001A JPH0799589B2 (en) | 1984-05-11 | 1984-05-11 | Optical pickup device |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS60237648A JPS60237648A (en) | 1985-11-26 |
JPH0799589B2 true JPH0799589B2 (en) | 1995-10-25 |
Family
ID=14098172
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP59094001A Expired - Lifetime JPH0799589B2 (en) | 1984-05-11 | 1984-05-11 | Optical pickup device |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0799589B2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR100988705B1 (en) * | 2002-08-29 | 2010-10-18 | 소니 주식회사 | Optical head and optical recording medium drive device |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE69817227T2 (en) | 1997-01-17 | 2004-06-17 | Matsushita Electric Industrial Co., Ltd., Kadoma | Optical scanning head and optical disk device using this |
JP2003045062A (en) * | 2001-07-27 | 2003-02-14 | Asahi Glass Co Ltd | Optical head device |
JP4003161B2 (en) | 2001-11-19 | 2007-11-07 | ソニー株式会社 | Optical head, recording / reproducing apparatus, and optical coupling efficiency variable element |
JP4240883B2 (en) * | 2001-12-27 | 2009-03-18 | ソニー株式会社 | Optical head and optical recording medium driving apparatus |
JP2003303433A (en) * | 2002-04-08 | 2003-10-24 | Sony Corp | Optical pickup and recording/reproducing device |
JP2009043370A (en) * | 2007-08-10 | 2009-02-26 | Sony Corp | Hologram recording and reproducing device and light source device |
JP2009093715A (en) | 2007-10-04 | 2009-04-30 | Sony Corp | Data recording and reproducing device, camera device, and data recording and reproducing method |
JP2009205734A (en) * | 2008-02-27 | 2009-09-10 | Nidec Copal Corp | Nd filter switching device |
JP5169582B2 (en) * | 2008-07-29 | 2013-03-27 | ソニー株式会社 | Optical pickup and optical disk apparatus using the same |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6083235A (en) * | 1983-10-13 | 1985-05-11 | Toshiba Corp | Optical head |
-
1984
- 1984-05-11 JP JP59094001A patent/JPH0799589B2/en not_active Expired - Lifetime
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR100988705B1 (en) * | 2002-08-29 | 2010-10-18 | 소니 주식회사 | Optical head and optical recording medium drive device |
Also Published As
Publication number | Publication date |
---|---|
JPS60237648A (en) | 1985-11-26 |
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