JPS6120057B2 - - Google Patents
Info
- Publication number
- JPS6120057B2 JPS6120057B2 JP53032306A JP3230678A JPS6120057B2 JP S6120057 B2 JPS6120057 B2 JP S6120057B2 JP 53032306 A JP53032306 A JP 53032306A JP 3230678 A JP3230678 A JP 3230678A JP S6120057 B2 JPS6120057 B2 JP S6120057B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- recording medium
- beams
- light beams
- reading
- 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
Links
- 238000000034 method Methods 0.000 claims description 16
- 230000003287 optical effect Effects 0.000 claims description 13
- 238000001514 detection method Methods 0.000 description 11
- 238000010586 diagram Methods 0.000 description 6
- 239000004065 semiconductor Substances 0.000 description 5
- 230000001360 synchronised effect Effects 0.000 description 4
- 230000010365 information processing Effects 0.000 description 3
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 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
- G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
- G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
- G11B7/0938—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following servo format, e.g. guide tracks, pilot signals
Description
【発明の詳細な説明】
本発明は光学的読み取り方法に関するものであ
る。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical reading method.
例えば、デイスク状の記録媒体上に、周心円状
または螺線状のトラツクに沿つて光学的不均一部
分を形成して、ビデオ情報やオーデイオ情報を記
録した、ビデオまたはオーデイオデイスクプレヤ
ーが種々提案されている。また、かかるデイスク
プレーヤーにおいて、記録媒体上に記録された情
報を光学的に読み取る方法として、例えば特開昭
49−50954号、同50−87003号公報等には、三本の
光ビームを用いる方法が開示されている。すなわ
ち、特開昭49−50954号公報に開示された読み取
り方法は、光源から出た光ビームをグレーテイン
グを通して三本の光ビームに分割し、この三本の
光ビームをハーフミラー、対物レンズを介してデ
イスク面に照射して、該デイスク面で反射した三
本の光ビームを対物レンズ、ハーフミラーを介し
て三つの受光素子で各別に受光するものである。
そして、これら三つの受光素子のうち、内側の受
光素子で受光した反射光によつて情報を読み取
り、両側の二つの受光素子で受光した反射光によ
つてトラツキング信号を検出している。また特開
昭50−87003号公報に開示された読み取り方法
は、上記特開昭49−50954号公報に開示された方
法において、グレーテイングを用いる代わりに、
三個の発光部分を有する半導体レーザーを用いる
点のみが異なるもので、この方法においてもデイ
スク面で反射された三本の光ビームを、三個の受
光部を有するシリコンフオトダイオードで受光し
て、情報を読み取ると共にトラツキング信号を検
出している。 For example, various video or audio disk players have been proposed in which video or audio information is recorded by forming optically non-uniform portions along circumferential or spiral tracks on a disk-shaped recording medium. has been done. In addition, as a method for optically reading information recorded on a recording medium in such a disc player, for example,
No. 49-50954, No. 50-87003, etc. disclose methods using three light beams. That is, the reading method disclosed in Japanese Patent Application Laid-Open No. 49-50954 divides the light beam emitted from the light source into three light beams through a grating, and divides the three light beams into a half mirror and an objective lens. The three light beams that are reflected by the disk surface are received by three light receiving elements through an objective lens and a half mirror.
Of these three light-receiving elements, information is read by the reflected light received by the inner light-receiving element, and a tracking signal is detected by the reflected light received by the two light-receiving elements on both sides. Furthermore, the reading method disclosed in JP-A No. 50-87003 uses grating instead of using the method disclosed in JP-A-49-50954.
The only difference is that a semiconductor laser having three light-emitting parts is used, and in this method, the three light beams reflected by the disk surface are received by a silicon photodiode having three light-receiving parts. It reads information and detects tracking signals.
上述した三本の光ビームを用いる従来の読み取
り方法においては、いずれも三つの受光素子また
は三つの受光部を有する受光素子を用いるもので
あり、デイスク面での三本の反射光ビームのそれ
ぞれを三つの受光素子または受光部のそれぞれに
独立して入射させる必要があるため、三つの受光
素子または受光部をそれぞれ空間的にある程度離
間して配置する必要がある。このため、情報読み
取り用の主ビームに対してトラツキング信号検出
用の二本の副ビームの成す角度度が大きくなり、
軸外の収差も考慮した高精度の光学系が必要にな
ると共にその調整も極めて困難である。また、グ
レーテイングを用いて三本の光ビームを得る方法
においては、三本の光ビームのそれぞれのスポツ
ト間隔を大きくする必要があることから、その回
転調整が極めて困難である。 The conventional reading methods using three light beams described above all use three light receiving elements or a light receiving element having three light receiving sections, and each of the three light beams reflected on the disk surface is Since it is necessary to make the light incident on each of the three light receiving elements or light receiving sections independently, it is necessary to space the three light receiving elements or light receiving sections apart from each other to some extent spatially. For this reason, the angle formed by the two sub beams for tracking signal detection with respect to the main beam for information reading becomes large.
A highly accurate optical system that takes into account off-axis aberrations is required, and its adjustment is extremely difficult. Furthermore, in the method of obtaining three light beams using gratings, it is necessary to increase the distance between the spots of each of the three light beams, making it extremely difficult to adjust the rotation thereof.
本発明の目的は、上述した欠点を除去し、少く
とも二本の光ビームを記録媒体に投射し、それら
の反射光または透過光を一つの受光部を有する受
光素子によつて受光してトラツキング信号を検出
することにより、簡単な光学系を用いることがで
き、しかもその調整が簡単な光学的読み取り方法
を提供せんとするにある。 An object of the present invention is to eliminate the above-mentioned drawbacks, project at least two light beams onto a recording medium, and track the reflected or transmitted light by receiving it with a light-receiving element having one light-receiving section. It is an object of the present invention to provide an optical reading method that uses a simple optical system by detecting a signal and that is easy to adjust.
本発明は、記録媒体に記録された情報を光学的
に読み取りにあたり、少く共二本の光ビームを異
なる位相で輝度変調して、前記記録媒体上に、ト
ラツクの方向に対して横方向に僅かりずらして投
射し、該記録媒体からの反射光または透過光を一
個の受光素子で受光し、これら光ビームを前記輝
度変調に基いて分離し、これらの受光光量を比較
してトラツキング信号を検出することを特徴とす
るものである。 In optically reading information recorded on a recording medium, the present invention modulates the brightness of at least two light beams with different phases so that a light beam can be placed on the recording medium in a direction transverse to the track direction. A single light receiving element receives reflected light or transmitted light from the recording medium, separates these light beams based on the luminance modulation, and detects a tracking signal by comparing the amounts of these received light beams. It is characterized by:
すなわち本発明によれば、異なる周波数または
位相によつて輝度変調された二本の副ビームを記
録媒体に投射し、それらの反射光または透過光を
一つの受光部を有する受光素子によつて受光して
トラツキング信号を検出するものであるから、二
本の副ビームをグレーテイングまたはそれぞれ独
立の光源から得る場合においても、受光素子上で
それらのスツト間隔を設ける必要がなく、したが
つて光学系の調整が簡単になると共に、コンパク
トな装置が実現できる。また、この場合情報読み
取り用の主ビームはグレーテイングまたは他の光
源から得ることができる。主ビームの記録媒体に
おける反射光または透過光を受光する受光素子
は、前記トラツキング検出用の副ビームを検出す
る受光素子とは別個に配置すればよい。 That is, according to the present invention, two sub beams whose brightness is modulated with different frequencies or phases are projected onto a recording medium, and their reflected or transmitted light is received by a light receiving element having a single light receiving section. Since the tracking signal is detected by the optical system, even when the two sub beams are obtained from gratings or independent light sources, there is no need to provide a spacing between them on the light receiving element, and therefore the optical system The adjustment becomes easy and a compact device can be realized. Also, in this case, the main beam for reading information can be obtained from a grating or other light source. A light receiving element that receives reflected light or transmitted light from the recording medium of the main beam may be disposed separately from a light receiving element that detects the sub beam for tracking detection.
更に本発明の目的は情報読み取り用の主ビーム
と、上述したトラツキング信号検出用の副ビーム
との記録媒体における反射光または透過光を、一
つの受光部を有する受光素子で受光して、情報お
よびトラツキング信号を検出できるようにするこ
とにより、光学系の構成およびその調整を簡単に
できる光学的読み取り方法を提供せんとするにあ
る。 A further object of the present invention is to receive the reflected light or the transmitted light on the recording medium of the main beam for reading information and the sub-beam for tracking signal detection mentioned above by a light receiving element having one light receiving part, and to detect the information and information. It is an object of the present invention to provide an optical reading method that allows easy configuration and adjustment of an optical system by detecting a tracking signal.
本発明は、記録媒体に記録された情報を光学的
に読み取りにあたり、少く共二本の光ビームと、
記録情報を読み取るための一本の光ビームとを用
い、前記少くとも二本の光ビームを異なる位相で
輝度変調し、これら変調光と前記記録情報読み取
り用の光ビームとを前記記録媒体上にトラツクの
方向に対して横方向に僅かにずらして投射し、こ
れら投射光における該記録媒体からの反射光また
は透過光を一個の受光素子で受光し、これらの受
光ビームを前記輝度変調に基いて分離して、記録
情報を読み取ると共に、変調光の受光光量を比較
してトラツキング信号を検出することを特徴とす
るものである。 The present invention optically reads information recorded on a recording medium using at least two light beams,
A single light beam for reading recorded information is used to modulate the brightness of the at least two light beams with different phases, and these modulated lights and the light beam for reading recorded information are directed onto the recording medium. The light beams are projected with a slight shift in the lateral direction with respect to the direction of the track, the reflected light or transmitted light from the recording medium in these projected light beams is received by a single light receiving element, and these received light beams are processed based on the brightness modulation. The device is characterized in that the recorded information is read out separately, and the amount of received modulated light is compared to detect a tracking signal.
すなわち本発明によれば、トラツキング信号検
出用の副ビームおよび情報読み取り用の主ビーム
の記録媒体における反射光または透過光を一つの
受光部を有する受光素子で受光するものであるか
ら、受光素子上での主および副ビームの各スポツ
ト間に間隔を設ける必要がなく、したがつて、光
学系にはさほど高精度のものは要求されないと共
に、その調整も比較的簡単に行なうことができ
る。更に、一つの受光素子によつて主および副ビ
ームを受光することにより、記録媒体上のトラツ
クの方向での各スポツト間隔を十分小さくするこ
とができるから、主ビームによつて走査されるト
ラツク部分に極めて近い位置でトラツキング信号
を検出でき、したがつて高精度のトラツキングを
行なうことができる。 That is, according to the present invention, since the reflected light or the transmitted light from the recording medium of the sub-beam for tracking signal detection and the main beam for information reading is received by the light-receiving element having one light-receiving part, There is no need to provide a space between the spots of the main and sub-beams, so the optical system does not require very high precision and can be adjusted relatively easily. Furthermore, by receiving the main and sub beams with one light receiving element, the distance between each spot in the track direction on the recording medium can be made sufficiently small, so that the track portion scanned by the main beam can be The tracking signal can be detected at a position extremely close to the target, and therefore highly accurate tracking can be performed.
以下図面を参照して本発明を詳細に説明する。 The present invention will be described in detail below with reference to the drawings.
第１図は本発明光学的読み取り方法を実施する
装置の一例の構成を示す線図である。本例では、
反射形のビデオデイスクの読り取り装置を示す。
半導体レーザ１は、水平面上に互いに分離された
三つの発光部２，３および４を具え、三本の光ビ
ームを射出する。発光部３には直流電源５を接続
して、ここから後述するデイスク上に記録された
ビデオ情報を読み取るための一定波長で一定強度
の光ビーム（以下ビームと称する）を射出させ、
発光部２および４にはビデオ情報の周波数よりは
相当低い100KHz前後の周波数f0で、位相θ１，
θ２が異なる（本例では180゜異なる）交流電源
２２および２３を接続して、それぞれ輝度変調さ
れた光ビーム（以下これらの光ビームを副ビーム
と称する）を射出させる。 FIG. 1 is a diagram showing the configuration of an example of an apparatus for carrying out the optical reading method of the present invention. In this example,
1 shows a reflective video disc reader;
The semiconductor laser 1 includes three light emitting sections 2, 3, and 4 separated from each other on a horizontal plane, and emits three light beams. A DC power supply 5 is connected to the light emitting unit 3, and a light beam (hereinafter referred to as a beam) of a constant wavelength and a constant intensity is emitted from there for reading video information recorded on a disk, which will be described later.
The light emitting units 2 and 4 have a frequency f 0 of around 100KHz, which is considerably lower than the frequency of video information, and a phase θ 1 ,
AC power supplies 22 and 23 having different θ 2 (different by 180° in this example) are connected to emit brightness-modulated light beams (hereinafter these light beams will be referred to as sub-beams).
半導体レーザ１から射出された主および副ビー
ムは、コリメータレンズ８で平行光に変換された
後、偏光プリズム９、1/4波長板１０および対物
レンズ１１を経てデイスク１２上に結像される。 The main and sub beams emitted from the semiconductor laser 1 are converted into parallel beams by a collimator lens 8, and are then imaged onto a disk 12 via a polarizing prism 9, a quarter-wave plate 10, and an objective lens 11.
デイスク１２上での主および副ビームの各スポ
ツトの位置は、第２図に示すように、副ビームの
各スポツト２′，４′を、トラツクの方向にみて、
主ビームのスポツト３′の前後とし、かつトラツ
クの方向に対して横方向に僅かにずらしておく。 The positions of the main and sub beam spots on the disk 12 are determined by looking at the sub beam spots 2' and 4' in the track direction, as shown in FIG.
It is located in front of and behind the main beam spot 3' and slightly offset laterally with respect to the direction of the track.
デイスク１２上で反射された、これら主および
副ビームは、対物レンズ１１、1/4波長板１０、
偏光プリズム９および集光レンズ１３を経て、一
つの受光部を有する受光素子１４に集光する。 These main and sub beams reflected on the disk 12 are transmitted through an objective lens 11, a quarter wave plate 10,
The light passes through the polarizing prism 9 and the condensing lens 13 and is condensed onto a light receiving element 14 having one light receiving section.
第３図は、第１図において受光素子１４に集光
したデイスク１２からの反射光から、ビデオ情報
およびトラツキング信号を検出する回路の一例の
構成を示す線図である。受光素子１４に集光され
たデイスク１２からの反射光は、その光量に応じ
た電気信号に変換され、増幅器１５で増幅され
る。増幅された電気信号は、ビデオ情報処理回路
１６、同期検波回路２４，２５にそれぞれ供給さ
れ、ビデオ情報処理回路１６でデイスク１２上に
記録されたビデオ情報が検出される。このビデオ
情報の周波数は一般に2MHz以上である。また同
期検波回路２４および２５では、供給された電気
信号からそれぞれ異なる位相で輝度変調された二
本の副ビームを検出して、それらの出力はそれぞ
れ差動増幅器２１に供給し、ここで両検波出力の
差によるトラツキング信号を検出する。本例で
は、このトラツキング信号に基き、差動増幅器２
１の出力が零となるように、対物レンズ１１を駆
動してトラツキングを行なう。 FIG. 3 is a diagram showing the configuration of an example of a circuit for detecting video information and tracking signals from the reflected light from the disk 12 that is focused on the light receiving element 14 in FIG. The reflected light from the disk 12 that is focused on the light receiving element 14 is converted into an electrical signal according to the amount of light, and is amplified by the amplifier 15. The amplified electrical signals are supplied to a video information processing circuit 16 and synchronous detection circuits 24 and 25, respectively, and the video information processing circuit 16 detects the video information recorded on the disk 12. The frequency of this video information is generally 2MHz or higher. In addition, the synchronous detection circuits 24 and 25 detect two sub-beams whose brightness is modulated with different phases from the supplied electrical signals, and their outputs are respectively supplied to the differential amplifier 21, where both detection Detects a tracking signal based on the difference in output. In this example, based on this tracking signal, the differential amplifier 2
Tracking is performed by driving the objective lens 11 so that the output of 1 becomes zero.
次に、第３図に示した回路におけるトラツキン
グ信号の検出方法を説明する。今、第４図ａおよ
びｂに示すように、デイスク１２上での主および
副ビームの位置が、トラツクの方向に対して右側
から左側にずれたとする。この場合、増幅器１５
の出力として得られる副ビームの受光々量に対応
する電気信号は、第５図ａに示すようになる。し
たがつて、この電気信号を同期検波回路２４およ
び２５でそれぞれ検波すれば、差動増幅器２１に
は、第５図ｂに示すような信号が供給されるか
ら、これら検波出力の差から常時トラツキング信
号を得ることができる。このようにして検出した
トラツキング信号に基いて、対物レンズ１１を駆
動し、デイスク１２上における主および副ビーム
の位置が、第２図に示すような位置となるように
トラツキングを行う。すなわち主ビームのスポツ
ト３′がトラツクの中心に位置し、かつ二本の副
ビームからの反射光量が等しくなるようにトラツ
キングを行なう。このようにすれば、常にビデオ
情報を高精度で読み取ることができる。 Next, a method of detecting a tracking signal in the circuit shown in FIG. 3 will be explained. Assume now that the positions of the main and sub beams on the disk 12 have shifted from the right side to the left side with respect to the track direction, as shown in FIGS. 4a and 4b. In this case, amplifier 15
An electrical signal corresponding to the amount of received sub-beam obtained as an output is shown in FIG. 5a. Therefore, if these electrical signals are detected by the synchronous detection circuits 24 and 25, the differential amplifier 21 is supplied with a signal as shown in FIG. I can get a signal. Based on the tracking signal thus detected, the objective lens 11 is driven, and tracking is performed so that the positions of the main and sub beams on the disk 12 are as shown in FIG. That is, tracking is performed so that the main beam spot 3' is located at the center of the track and the amounts of reflected light from the two sub beams are equal. In this way, video information can always be read with high precision.
なお、本発明は上述した例にのみ限定されるも
のではなく幾多の変更または変形が可能である。
例えば、情報読み取り用の主ビームおよびトラツ
キング信号検出用の二本の副ビームは、それぞれ
独立した半導体レーザやガスレーザから得てもよ
く、また一つのレーザ光源からの光ビームを、グ
レーテイングによつて三本の光ビームに分割して
得てもよく、あるいは二つのレーザ光源を用い、
そのうちの一つのレーザ光源からの光ビームをグ
レーテイングによつて二本の光ビームに分割して
副ビームとして三本の光ビームを得てもよい。ま
たトラツキング信号検出用の二本の副ビームは、
輝度変調可能な光ビームであればよいから、必ず
しもレーザ光源から得る必要はない。 Note that the present invention is not limited to the above-mentioned examples, and can be modified or modified in many ways.
For example, the main beam for information reading and the two sub beams for tracking signal detection may be obtained from independent semiconductor lasers or gas lasers, or the light beam from one laser light source may be obtained by grating. It may be obtained by splitting it into three light beams, or by using two laser light sources.
The light beam from one of the laser light sources may be divided into two light beams by grating to obtain three light beams as sub-beams. In addition, the two sub beams for tracking signal detection are
It does not necessarily have to be obtained from a laser light source, as it only needs to be a light beam that can be modulated in brightness.
第１図は本発明光学的読み取り方法を実施する
装置の一例の構成を示す線図、第２図は第１図に
示す装置においてデイスク上での三本の光ビーム
の位置関係を示す線図、第３図は第１図に示す装
置においてビデオ情報とトラツキング信号とを検
出する回路の一例の構成を示す線図、第４図ａ，
ｂおよび５図ａ，ｂは第３図に示す回路において
トラツキング信号を検出する態様の一例を示す線
図である。
１…半導体レーザ、２，３，４…発光部、
２′，３′，４′…スポツト、５…直流電源、１２
…デイスク、１４…受光素子、１６…ビデオ情報
処理回路、２１…差動増幅器、２２，２３…交流
電源、２４，２５…同期検波回路。
FIG. 1 is a diagram showing the configuration of an example of a device for carrying out the optical reading method of the present invention, and FIG. 2 is a diagram showing the positional relationship of three light beams on a disk in the device shown in FIG. , FIG. 3 is a diagram showing the configuration of an example of a circuit for detecting video information and tracking signals in the apparatus shown in FIG. 1, and FIG. 4a,
5b and 5a and 5b are diagrams showing an example of a manner in which a tracking signal is detected in the circuit shown in FIG. 3. 1... Semiconductor laser, 2, 3, 4... Light emitting part,
2', 3', 4'...Spot, 5...DC power supply, 12
... disk, 14 ... light receiving element, 16 ... video information processing circuit, 21 ... differential amplifier, 22, 23 ... AC power supply, 24, 25 ... synchronous detection circuit.
Claims (1)
るにあたり、少く共二本の光ビームを異なる位相
で輝度変調して、前記記録媒体上に、トラツクの
方向に対して横方向に僅かにずらして投射し、該
記録媒体からの反射光または透過光を一個の受光
素子で受光し、これら光ビームを前記輝度変調に
基いて分離し、これらの受光光量を比較してトラ
ツキング信号を検出することを特徴とする光学的
読み取り方法。 ２ 記録媒体に記録された情報を光学的に読み取
るにあたり、少く共二本の光ビームと、記録情報
を読み取るための一本の光ビームとを用い、前記
少く共二本の光ビームを異なる位相で輝度変調
し、これら変調光と前記記録情報読み取り用の光
ビームとを前記記録媒体上に、トラツクの方向に
対して横方向に僅かにずらして投射し、これら投
射光における該記録媒体からの反射光または透過
光を一個の受光素子で受光し、これらの受光ビー
ムを前記輝度変調に基いて分離して、記録情報を
読み取ると共に、変調光の受光光量を比較してト
ラツキング信号を検出することを特徴とする光学
的読み取り方法。[Claims] 1. In optically reading information recorded on a recording medium, at least two light beams are intensity-modulated with different phases, and light beams are placed on the recording medium transversely to the track direction. A single light receiving element receives reflected light or transmitted light from the recording medium, separates these light beams based on the luminance modulation, and tracks the received light by comparing the amounts of the received light. An optical reading method characterized by detecting a signal. 2. When optically reading information recorded on a recording medium, at least two light beams and one light beam for reading the recorded information are used, and the at least two light beams are set at different phases. These modulated lights and the light beam for reading the recorded information are projected onto the recording medium with a slight shift in the lateral direction with respect to the track direction, and the intensity of the light from the recording medium in these projected lights is Receive reflected light or transmitted light with a single light receiving element, separate these received light beams based on the luminance modulation, read recorded information, and detect a tracking signal by comparing the amounts of received modulated light. An optical reading method characterized by:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3230678A JPS54125005A (en) | 1978-03-23 | 1978-03-23 | Optical reading method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3230678A JPS54125005A (en) | 1978-03-23 | 1978-03-23 | Optical reading method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS54125005A JPS54125005A (en) | 1979-09-28 |
| JPS6120057B2 true JPS6120057B2 (en) | 1986-05-20 |
Family
ID=12355256
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3230678A Granted JPS54125005A (en) | 1978-03-23 | 1978-03-23 | Optical reading method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS54125005A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5655806U (en) * | 1979-10-02 | 1981-05-15 | ||
| JPS5661045A (en) * | 1979-10-25 | 1981-05-26 | Olympus Optical Co Ltd | Optical information reader |
| JP2857553B2 (en) * | 1992-11-05 | 1999-02-17 | 株式会社三協精機製作所 | Optical pickup beam angle detection method |
-
1978
- 1978-03-23 JP JP3230678A patent/JPS54125005A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS54125005A (en) | 1979-09-28 |
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