JPS6069843A - Optical head - Google Patents

Abstract

PURPOSE:To record or read information well at a high speed for a long time continuously by condensing a beam spot, which is used for recording or reading at least, and a preceding beam spot for reading, which precedes said beam spot, on the same track. CONSTITUTION:A beam 14 for recording is generated by a light source 11. A beam 17 for reading and a preceding beam 18 are generated by a light source 16. Beams 17, 18, and 14 are multiplexed by a multiplex laser light processing part 19 and pass a condensing part 20 and are condensed in a line on a storage medium 21 along tracking guides 23..., and a preceding spot 24, spots 25 and 26 for recording and reading are formed in order on them. The reflected light from the storage medium 21 is distributed to a preceding beam reflected light quantity detecting part 27, a reading part 28, an off-track detecting part 29, and a defocus detecting part 30 through the light processing part 19.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is used, for example, in a li'JJ image file file, COM (computer out-of-not-memory), etc., and uses focused light to make a hole in the recording BE of an information storage medium, or to change the refractive index. , reflectance 4, rRegarding an optical head capable of recording information by locally causing a change in state, such as changing optical characteristics, and reproducing information therefrom.

[Technical background of the invention and its problems]

Conventionally, optical heads of the above type are known that are capable of recording information at high speed and have a function of simultaneously reading the recording and confirming the recorded contents.

In this optical head, as shown in Fig. 1, a hole is made in the recording layer 2 on the information storage body, and the state is locally changed by changing optical characteristics such as refractive index and reflectance. In order to record information, a blinkable recording laser beam 3 is focused on the recording layer 2 of the information storage medium 1 to form a recording focused beam spot 4. The recording beam spot 4 moves along a groove-shaped tracking guide 5. Then, when the recording laser beam 3 is turned on, a local state change occurs on the recording layer 4 of the information storage medium 1, and new recording is performed ('+'J information signal bit 6
... is formed. Immediately after recording, a reading laser beam 7 is focused to confirm the recorded content.
A condensed beam spot 8 for reading is formed. Record f-J
Laser beam 3 and reading,! The v-sa~ beam 7 for lJ passes through the same objective lens 9 in order to be condensed, but
Since the optical axis W of the recording laser beam 3 and the optical axis r of the reading laser beam 7 are slightly tilted in the state of parallel light before passing through the objective reflex lid, the recording 1a of the information storage medium 1
2, the H6 recording condensed beam spot 4 and the read condensed beam spot 8 are located at positions 11 apart from each other.

However, in this optical head, the reading focused beam spot 8 whose distribution state should be inspected is always behind the recording focused beam spot 4 in the traveling direction. Even if an error is detected during the recording of the 117 report, it does not mean that an error has already been recorded.Especially if the following situations occur, a serious error will occur. It becomes 5A.

Medium: If a track goes off the track during continuous recording and moves to an area that has already been recorded, part of the area that has already been recorded will be destroyed before the abnormality is detected. Furthermore, if the trunk is disconnected during continuous recording and a portion where only one recording has been made is recorded, a fairly wide area before and after the erroneously recorded portion will be erased.

(11) If recording starts at a place where it should not have been recorded due to some mistake, by the time the error in the recording start position 1 is detected, recording has already started and the recorded content will already be recorded. or erase unrecorded areas.

Furthermore, if it is detected that the state of the part to be recorded is bad (for example, there is a part that has been recorded incorrectly or incorrectly), recording will be stopped once and the reading light beam spot 8 will be used to detect the problem. After confirming and memorizing the range of the condition, it is necessary to start recording from the point excluding that part, which takes time.

[Purpose of the invention]

The present invention has been made based on the above-mentioned circumstances, and its object is to provide an optical system that can efficiently record or read 16" information on an information recording medium at very high speed and continuously for a long time. It is possible to provide the head.

[Summary of the invention]

In order to achieve the above-mentioned object, the present invention provides li! Beams 1 on the track formed on the information storage body? In an optical head that can perform at least one of recording and reading information by focusing a beam, -4? The above (H report memory 4) that precedes this Beano spot
゛ﾾI・(1) The preceding beam for reading the above information is characterized by being provided with means for condensing the light onto the same track on the above information storage medium.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. What about in Figures 2 and 3? This is a light source for the C29, and is turned off when reading information. When recording new information, a signal containing the information to be recorded is transmitted from the distribution information signal generator 12 to the recording laser drive circuit 13, and in accordance with this, the recording laser light source 1 is activated. blinks and a recording laser beam 14 is formed. The light emitted from the back side of the recording laser light source 11 is received by the recording laser sight monitor part 15, and the output of the recording laser light quantity monitor part 15 is adjusted so that the recording laser light quantity when turned on is always constant. Recording laser drive circuit 1.111C negative feedback (feedback) is performed. Reference numeral 16 is a multiple laser light source for reading, and the amount of light emitted from it is always kept constant regardless of whether information is being recorded or read.

A reading radar beam 17 and a leading laser beam 18 are formed from the reading multiple radar light source 16. In the case of the multiple laser light source 16 for reading, a part of the light emitted from it is also used for reading.
7, and negative feedback is provided to the laser beam 1jh circuit 118 for taking ii'Ifi, thereby stabilizing the amount of output light.

The laser beam 17 for acquisition, the preceding laser beam 18, and the laser beam 14 for recording are integrated in a multiplex radar light processing section 19, and then sent to a condensing section (objective lens) 20.
Through this, the tracking light is focused in a line on the recording layer 22 of the information storage medium 21 along the id 23 . and,
A leading beam spot 24, a recording beam spot 25, and a reading beam spot 26 are formed in this order on the tracking side 23. Further, the light reflected on the information storage medium 21 is returned to the condensing section (objective lens) 20.
After passing through the multiple laser beam processing unit 19, the preceding laser beam is reflected! −”° detection section 27, information signal reading section 28, track deviation detection section 29, defocus detection section 3
are respectively distributed to θ. However, the information signal reading section 28
, the track deviation detection section 29 is often shared by the same photodetector. The outputs of the track deviation detection section 29 and the out-of-focus detection section 30 are trunk deviation, track deviation which is corrected by moving the condenser (objective lens) 2o in two axial directions via the defocus correction circuit 31, The signal is sent to the defocus correction drive circuit 32. In addition, Figures 3 and 4
Reference numeral 33 in the figure indicates an information signal pit.Furthermore, as shown in Figure gJ5, the multiplex laser light source 16 for reading) is equipped with one laser light source 34 for reading, and a multiplex laser light generator 35 generates a large number of pits. The laser beam is divided into a reading laser beam 17 and a preceding laser beam 18. Further, the multiple laser beam processing section 19 is divided into a laser beam combining section 36, an isolation section 37, and a laser beam FliI section 38. The multiple reading laser beam (reading laser beam 17 and preceding laser beam 18) generated by the multiplex laser beam generating section 35 and the recording laser beam 14 are combined by the laser beam combining section 36, and a similar The light path passes through the

The multiple laser beam that has passed through the radar beam combining section 36 passes through a polarization beam sinter and an isolation section 37 consisting of a λ/4 plate, and reaches the information storage medium 21 via a condensing section (objective lens) 20. The multiple laser beams reflected on the information storage medium 21 and passed through the condensing section (objective lens) 20 again are directed toward the laser beam separation section 38 by the action of the isolation section 37 . This multiplexed laser beam is separated by a radar beam splitter 1 (unit 38) and is separated by a leading laser beam reflected light -%nQ output unit 27 and a defocus detection unit 3.
0. The signal is divided and sent to the track deviation detection section 29 and the information signal reading section 28, respectively.

As shown in FIG. 6, the recording laser light source 11 includes a constant voltage source 39, a gate circuit 40° and a current control circuit 41.
are connected in series.

When reading information, the gate circuit 40 is closed and no current flows. When recording the N information, the r-to circuit 40 is opened only when forming a bit in accordance with the output of the recording information signal generator 12. A current is supplied from the constant voltage source 39 to the recording laser light source 11 via the gate circuit 40 and the current control circuit 41. By controlling this supply current value with the current control circuit 4), the amount of intermittent light emitted from the recording laser light source 11 is controlled. Immediately after starting recording information, the switching unit 42 is activated to control the amount of recording laser light. The output voltage from the setting reference voltage generator 43 is directly supplied to the current control circuit 41, and current control is performed based on the voltage value.Recording laser light source 11
A laser beam intermittently generated from the back side of the recording laser beam is received by a part 15 of the recording laser light amount monitor. Further, in synchronization with the signal from the recording information signal generator 12, the sample and hold circuit 44 samples and holds the output of the recording laser light amount monitor part 15. Then, this sample-held value and the basic single voltage generator 4 for setting the recording laser light intensity are used.
The voltage of another voltage created in step 3 is a differential circuit (subtraction circuit) 4
5 and is negatively fed back to the current control circuit 41.

Immediately after the start of recording, the base voltage generation unit 43 for setting the recording laser light amount and the current control circuit 41 are connected, but immediately after the start of recording, the switching unit 42 connects the difference circuit (subtraction circuit) 45 to the current control circuit 41. are switched so that they are connected directly.

Note that instead of the sample hole 1 circuit 44, a peak detection circuit 46 is used as shown in FIG.
The output of the monitor part 15 may be sampled and held and compared with the recording voltage of the reference voltage generator 430 for setting the recording laser beam μ. In contrast to 1, the electric signal is indicated by a solid arrow, and the light li1
．． lG is indicated by a dashed arrow.

According to the above configuration, [A] An abnormal state of the recording button can be detected, and unnecessary destruction on the surface of the recording layer 22 can be prevented.

■ Preformatted onto the information storage medium 2 (
By reading the information (formed when creating the master disc) using the preceding 4j% optical vinyl spot, it is possible to set the track number and sector position in advance before recording.

■ During recording, even if the focused beam spot accidentally enters an area where it has already been recorded, it can be detected by the preceding focused beam spot, so it is possible to drill again in the area where it was mistakenly recorded. It won't break if opened.

■ Accidentally focused beams while recording, J? Even if the knot strays into an unrecorded area where it should not originally be recorded, the pre-formatted information is searched for at the same time in the pre-focused beam spot and the read-out focused beam spot, so it is useful even when there is no pre-focused beam spot. Abnormalities can be detected much faster, and the time required to record abnormalities can be significantly reduced.

[B″l Continuous recording can be performed by skipping inappropriate recording areas without stopping continuous recording.

■ It is possible to check in advance whether the area has a high error rate due to dust, scratches, etc. before recording using the advance focused beam spot.

■ Advance focused beams 7J? Tsutoyo! l) Since it is possible to determine where on the surface of the recording layer is an inappropriate recording area caused by scratches, previous erroneous recording, etc., it is possible to continue recording by skipping only that area during continuous recording.

〔Effect of the invention〕

As explained above, according to the present invention, BEAMS 7J? In an optical head capable of recording and/or reading information by condensing a beam, a beam spot for recording and/or reading information, and a beam spot preceding the beam spot are used. Since the preceding beam spot for reading the information on the information storage medium is focused on the same track on the information storage medium, the information storage medium can be read at a very high speed and continuously for a long time. It has excellent effects such as being able to record or read information well.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a conventional example, the second till shows a 7" lock showing an embodiment of the present invention, and FIG. 3 shows the state of a laser beam directed onto an information storage medium in an IWJ embodiment. F view, FIG. 4 is a plan view showing the beam spot on the information storage medium in the same embodiment, and FIG.
FIG. 6 is a block diagram showing a drive system of the recording laser light source in the same embodiment, and FIG. 7 is a block diagram showing another part of the drive system of the recording laser light source in the same embodiment. It is a block diagram showing an example. DESCRIPTION OF SYMBOLS 11... Laser light source for recording, 14... Laser beam for recording, 16... Multiple laser light source for reading, 1
7... Laser beam for reading a lot, 18... Leading ~
Da beam, 2θ... converging section (objective lens, e), 21
...information storage medium, 24...preceding beam spot,
25... Beam spot for recording, 26... Beam spot for reading.

Claims (1)

[Claims] In a device capable of recording and/or reading information by condensing beam bits onto tracks formed on an information storage body, a beam beam for recording and/or reading information is provided. , J? An optical head comprising means for converging a leading beam spot for reading information on the information storage medium preceding the Knot, this beam, and the JP Knot onto the same track on the information storage medium.