JPS58212627A - Detecting device of mirror surface - Google Patents
Detecting device of mirror surfaceInfo
- Publication number
- JPS58212627A JPS58212627A JP9480382A JP9480382A JPS58212627A JP S58212627 A JPS58212627 A JP S58212627A JP 9480382 A JP9480382 A JP 9480382A JP 9480382 A JP9480382 A JP 9480382A JP S58212627 A JPS58212627 A JP S58212627A
- Authority
- JP
- Japan
- Prior art keywords
- output
- level
- signal
- mirror surface
- voltage
- 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
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B19/00—Driving, starting, stopping record carriers not specifically of filamentary or web form, or of supports therefor; Control thereof; Control of operating function ; Driving both disc and head
- G11B19/02—Control of operating function, e.g. switching from recording to reproducing
- G11B19/12—Control of operating function, e.g. switching from recording to reproducing by sensing distinguishing features of or on records, e.g. diameter end mark
Landscapes
- Optical Recording Or Reproduction (AREA)
Abstract
Description
【発明の詳細な説明】
本発明はＤＡＤプレーヤ、ビデオディスクプレーヤ等の
ディスクの鏡面検出装置に関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mirror surface detection device for a disc such as a DAD player or a video disc player.
ＣＤ方式のディジタルオーディオディスク（ＤＡＤ）は
記録密度管上けるために等線速度記録されている。この
ためディスクの再生においては、内周と外周で回転数を
変化させる等線速度制御（ＣＬＶサーボ）が必要であり
、このための制御信号はディスクに記録されている同期
信号である。CD-based digital audio discs (DAD) are recorded at constant linear speeds to increase recording density. Therefore, when playing a disc, constant linear velocity control (CLV servo) is required to change the rotation speed between the inner and outer circumferences, and the control signal for this is a synchronization signal recorded on the disc.
またディスクは片面記録であシ、裏面は信号が記録され
ていない鏡面である。このためディスクを裏がえしで装
着された場合には同期信号が得られず、モータサーボは
制御不能となシ、暴走する場合がある。Also, the disc has single-sided recording, and the back side is a mirror surface on which no signals are recorded. For this reason, if the disk is installed upside down, a synchronizing signal cannot be obtained, and the motor servo may become uncontrollable and run out of control.
本発明の目的は、ディスク再生面の信号の有無を検出す
る鏡面検出装置を提供することにあるＯ
このため本発明は、ディスク読み出し信号の最大レベル
を検出するミラー面レベル検出器と最小レベルを検出す
るビット面レベル検出器を設け、鏡面の場合には両レベ
ル検出器の出力が同一のレベルになることに着目し、ミ
ラー面しベル６力を分圧したレベルよりビット面レベル
が高くなった′ことを比較器で検出することにより、デ
ィスクの差忙よる信号の大小に影響されずに安定に鏡面
を検出するものである。SUMMARY OF THE INVENTION An object of the present invention is to provide a mirror surface detection device that detects the presence or absence of a signal on a disc playback surface. Therefore, the present invention provides a mirror surface level detector that detects the maximum level of a disc read signal, and a mirror surface level detector that detects the minimum level of a disc read signal. We installed a bit surface level detector to detect the surface, and focused on the fact that in the case of a mirror surface, the output of both level detectors would be the same level. By detecting this with a comparator, the mirror surface can be stably detected without being affected by the magnitude of the signal due to the difference in disk speed.
第１図は本発明の一実施例を示す図である。FIG. 1 is a diagram showing an embodiment of the present invention.
第１図１ｃおいて、１１Ｉｉ情報記録デイスク、２はデ
ィスクモータ、３は信号読取装置である光学式ピックア
ップ、４け光電変換器、５は読取信号の最大レベルを検
出するミラー面レベル検出器、６は読取信号の最小レベ
ルを検出するビット面レベル検出器、１６．１８は正の
電圧供給端子、１７．１９は負の電圧供給端子、７は分
圧器、８は比較器である。第１図においてモータ２が回
転しておシ、信号トラックを追従するトラックサーボが
動作していない状態では、光学式ビン・クアップ３の光
出力を光電変換器４で光−電圧変換した出力は第２図４
出力に示すように、ディスクの情報記録面では（ａｌの
如く信号が出力され、鏡面ではＣｂ）の如くなる。この
４出力をレベル検曳器５．６ Ｋ入力することによシ、
信号の最大レベル、最小レベルがそれぞれレベル検出器
５，６の出力に得られる。レベル検出器５は信号の最大
値を検出してホールドする周知のエミッタホロワ検波器
をトランジスタ１０．抵抗２２．容量１１で構成し、ト
ランジスタ１０［よるベース・エミッタ電圧降下分をト
ランジスタ１２で補正している。従ってレベル検出器５
の出力には入力信号の最大レベルが出力ｆされる。レベ
ル検出器６も同様な原理による最小レベル検出器である
。トランジスタ１５をＰＮＰ型とすることによシ最小レ
ベルを検出する。ビット面レベル検出器６に第２図（α
）４出力に示すように最小レベルのエンベロープが時間
と共に変動する信号が入力された場合にも、エンベロー
プの周期に対して容量１４と抵抗２３で決定される時定
数を大きくとることによシ最小レベルをホールドするこ
とが可能である。第２図（α）に示す情報記録面再生の
場合には、４出力の図に示すように最大レベル５出力と
最小レベル６出力が検出できる。この最低レベルは最大
レベルを１とした場合、０．６以下と々るようにディス
ク規格で決まって込る。このため７の分圧比、Ｑｏ、６
以上−例として０．７とすれば、比較器８０入力は分圧
器７の出力の方が、レベル検出器６の出力より高くなり
、出力９はＨｌとなる。一方ディスクの鏡面を再生した
場合には、光電変換器４の出力は、第２図（ｂ）のよう
になり、レベル検出器５．６の出力は共に最大レベルと
なシ、一致する。７出力は５出力の０．７倍となるので
比較器８０入力は７出力よ一す、６出力の方が高くなり
、出力９はＬＯとなって鏡面が検出できる。本発明によ
ればディスクの反射率や信号の変１１１［が変化しても
、上述の関係が保たれるため無調整で安定に鏡面を検出
することが可能である。In FIG. 1c, an 11Ii information recording disk, 2 a disk motor, 3 an optical pickup as a signal reading device, a 4-piece photoelectric converter, 5 a mirror surface level detector for detecting the maximum level of the read signal, 6 is a bit plane level detector for detecting the minimum level of the read signal, 16.18 is a positive voltage supply terminal, 17.19 is a negative voltage supply terminal, 7 is a voltage divider, and 8 is a comparator. In FIG. 1, when the motor 2 is rotating and the track servo that follows the signal track is not operating, the optical output of the optical bin pickup 3 is converted from light to voltage by the photoelectric converter 4. Figure 2 4
As shown in the output, the information recording surface of the disc outputs a signal such as (al), and the mirror surface outputs a signal such as Cb. By inputting these 4 outputs to a level detector 5.6K,
The maximum and minimum levels of the signal are obtained at the outputs of level detectors 5 and 6, respectively. The level detector 5 is a well-known emitter follower detector that detects and holds the maximum value of the signal, and the transistor 10. Resistance 22. It is composed of a capacitor 11, and the base-emitter voltage drop caused by the transistor 10 is corrected by the transistor 12. Therefore, the level detector 5
The maximum level of the input signal is outputted to the output f. Level detector 6 is also a minimum level detector based on the same principle. By making the transistor 15 a PNP type, the minimum level is detected. Figure 2 (α
) Even when a signal whose minimum level envelope changes over time is input as shown in output 4, the minimum level can be minimized by setting a large time constant determined by capacitor 14 and resistor 23 with respect to the period of the envelope. It is possible to hold the level. In the case of information recording surface reproduction shown in FIG. 2 (α), maximum level 5 outputs and minimum level 6 outputs can be detected as shown in the diagram of 4 outputs. This minimum level is determined by the disc standard to be 0.6 or less when the maximum level is 1. Therefore, the partial pressure ratio of 7, Qo, 6
For example, if 0.7 is used as an example, the output of the voltage divider 7 will be higher than the output of the level detector 6, and the output 9 will be Hl. On the other hand, when the mirror surface of the disc is reproduced, the output of the photoelectric converter 4 becomes as shown in FIG. 2(b), and the outputs of the level detectors 5, 6 are both at the maximum level. Since the 7th output is 0.7 times the 5th output, the comparator 80 input is higher than the 7th output, the 6th output is higher, and the output 9 becomes LO, allowing the mirror surface to be detected. According to the present invention, even if the reflectance of the disk or the signal change 111 changes, the above-mentioned relationship is maintained, so it is possible to stably detect a mirror surface without adjustment.
以上述べたように本発明によれば、ディスクの反射率、
変調度等のバラツキの影響を受けることなく安定忙鏡面
を検出することが可能と々ったので、鏡面検出器の出力
に応じて、ＣＬＶサーボの暴走防止や、ディスク裏面警
告を行うことが可能と々りた。As described above, according to the present invention, the reflectance of the disk,
Since it is possible to detect a stable mirror surface without being affected by variations in modulation level, etc., it is possible to prevent runaway of the CLV servo and issue a disk backside warning according to the output of the mirror surface detector. It was amazing.
第１図は本発明の一実施例を示す図、第２図は第１図の
各部波形を示す図である。
５・・・最大レベルを検出する第１のレベル検出器６・
・パ最小レベルを検出する第２のレベル検出器７・・・
分圧器
８・・・比較器FIG. 1 is a diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing waveforms of various parts of FIG. 1. 5... First level detector 6 for detecting the maximum level.
・Second level detector 7 for detecting the minimum level...
Voltage divider 8... comparator
Claims (1)
装置１、読取装置出力の記録情報信号の最大レベルを検
出する第１のレベル検出器。 該記録情報信号の最小レベルを検出する第２のレベル検
出器、前記第１のレベル検出器の出力電圧を分圧する分
圧器、該分圧器出力と前記第２のレベル検出器出力とを
比較する比較器を備えてなることを特徴とする鏡面検出
装置。 ２ 前記第１のレベル検出器の出力電圧は分圧する分圧
器の分圧比がα６以上とした特許請求の範囲第１項記載
の鏡面検出装置。[Claims] 1. In an information recording disc reproducing device, an information reading device 1, a first level detector for detecting the maximum level of a recorded information signal output from the reading device. a second level detector that detects the minimum level of the recorded information signal; a voltage divider that divides the output voltage of the first level detector; and a voltage divider that compares the output of the voltage divider with the output of the second level detector. A mirror surface detection device characterized by comprising a comparator. 2. The specular surface detection device according to claim 1, wherein the output voltage of the first level detector is divided by a voltage divider having a voltage division ratio of α6 or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9480382A JPS58212627A (en) | 1982-06-04 | 1982-06-04 | Detecting device of mirror surface |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9480382A JPS58212627A (en) | 1982-06-04 | 1982-06-04 | Detecting device of mirror surface |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS58212627A true JPS58212627A (en) | 1983-12-10 |
Family
ID=14120214
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9480382A Pending JPS58212627A (en) | 1982-06-04 | 1982-06-04 | Detecting device of mirror surface |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58212627A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4682314A (en) * | 1982-08-30 | 1987-07-21 | Hitachi, Ltd. | Disc playback apparatus |
-
1982
- 1982-06-04 JP JP9480382A patent/JPS58212627A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4682314A (en) * | 1982-08-30 | 1987-07-21 | Hitachi, Ltd. | Disc playback apparatus |
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