JPS5977606A - Reproducing device of digital disc - Google Patents

Abstract

PURPOSE:To decide a reproducing condition immediately by reproducing only a reproducing starting part of a disc under the reproducing condition of reference recording density, discriminating recording density discriminating information and then deciding the reproducing condition in accordance with the prescribed recording density due to the discriminated output. CONSTITUTION:An optical pickup part 6 is provided with a laser light source, a lens system, a photodetector, etc. In order to enable the pickup part to be replaced by a pickup proper to the recording density of the disc, a reproducing circuit 7 provided with a head amplifier and a digital signal extracting part is built in the optical pickup part 6. The pickup part 6 scans the recording range part 5 of the disc 1 in the radius direction from the inner periphery part to the outer periphery part.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a reproducing apparatus for a digital disc, such as an optical audio disc, on which information is recorded in digital form.

BACKGROUND TECHNOLOGY AND PROBLEMS Digital discs have many uses compared to analog discs. That is, 1. For PCM audio information 2. For video information (525 scanning lines, NTSC system) 3. For high resolution video information 4. Still image 5. Still image with music 6. Mosaic image with dot display 7. Captain system It covers a wide variety of systems, including text and graphic information such as teletext, and microcomputer GLODARAM.

In these multipurpose digital discs, for example, P
Even if the recording storage size is sufficient for commercial audio, if the same recording density is used for other purposes, such as video signals, the recording and reproducing time will be shortened. Therefore, signals are recorded on video discs at a higher density than on audio discs. Further, when the information recorded on the disk is a computer programmer or the like, the recording density is relatively low because the error rate of the recorded data is important. Furthermore, even for the same information signal, if the long recording and reproducing time is treated as 8 without changing the disc size, the recording density must be increased.

By the way, as methods for increasing the recording density, techniques such as (1) reduction in bit size, (2) reduction in track pitch, (2) multi-sided recording and reproduction, and (2) multi-sided recording and reproduction can be considered. In the case of methods (1) and (2), reproduction can be performed using EJ by changing the disk rotation speed and the scanning speed of the pickup, and if necessary, changing to a pickup for use with a laser beam that is thinner than the standard one.

On the other hand, the multi-level recording/reproduction shown in Fig. 1 does not involve recording as a 2-1 signal of rOJrlJ using something with a simple constant depth, such as the pits of an optical audio disc, for example. If the depth of one bit (2) of the disk (1) is changed in a stepwise manner as shown in FIG. It is something to be regenerated. In this case, reproduction requires a special pickup different from the pickup of the PCM audio disc reproduction apparatus.

Furthermore, multi-sided recording and reproduction refers to two-sided recording and reproduction shown in FIG. 2, for example. It has two laser beam sources and two light receiving sections, and the recording surface of the disk (1) is perpendicular to the direction of arrow A in the figure. The pickup element (3) is separated into two parts having different slopes, ie, a surface (1h) perpendicular to the direction of the arrow B which intersects with the surface Oa), and has a pair of light sources and a light receiving section. ) are provided on each surface for recording and reproduction. In this case as well, a dedicated pickup having two pickup elements is required for reproduction.

It is conceivable that a single playback device may be used to play back multipurpose digital discs recorded at a wide variety of recording densities as described above. In other words, for example, a device may be used to restore a signal picked up from a disk as a digital signal, and a decoder for decoding each digital information may be attached to this device, or each decoder may be attached to a device that decodes each digital information. It is conceivable that the decoder is built in the decoder and set to 1 so that the decoder is selected according to the digital information to be reproduced.

When playing discs with different recording densities as described above in such a playback device, it is necessary to adjust the speed of the disk according to the recording density or replace it with a dedicated pickup, as described above. be.

However, manually switching the rotational speed is extremely troublesome because there are many set speeds. Even if you replace the disc with a dedicated pickup, it is still troublesome because you have to read the instructions on the disc label, for example, to determine which pickup to use for that disc.

Purpose of the Invention In view of the above-mentioned points, the present invention provides the ability to automatically load a disc into an apparatus, and adjust the recording speed to an appropriate recording speed according to the recording density.
It is an object of the present invention to make it possible to set playback conditions such as "1" and to be able to immediately determine playback conditions such as which pickup to use, for example.

Summary of the Invention The present invention provides a disc in which a digital signal is recorded at a certain recording density, and information identifying the recording density is recorded at the reproduction start position under reproduction conditions of the standard recording density. The apparatus reproduces only the playback start part of the disc under the playback conditions of the standard recording density, determines the recording density identification information, and determines the playback conditions according to the predetermined recording density based on the output of the determination. By providing a digital disc reproducing apparatus (i) which is configured to have the following characteristics and display a display indicating the recording density, a highly user-friendly reproducing apparatus has been realized.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

In this case, the disc to be played by the playback device is a wide variety of discs as mentioned at the beginning, but the 11th play start position part of this disc, for example, the 2nd inner circumference of the disc (1) at the 3rd M. The recording area (4) (indicated by diagonal lines in the figure) contains the recording density information of this disc (1),
For example, information such as [lF raw rotation speed is recorded. Furthermore, this recording portion (4) is recorded at the most standard recording density among various recording densities, and therefore at a standard speed. , Th, In figure P143, disk (1
) of radial d of f! Ii′4. The music part (5) is a recording part of digital data, and the pickup sequentially traces it from the inner circumference side to the outer circumference 1H11. Note that (6) is a label portion of the disc, and information such as recording accuracy and recording density is generally written on this label portion (6).

In this invention, the playback start recording portion (
4) The recording density (Ti information) is used to automatically set the t11 raw conditions such as the playback speed of the disc, and to display information corresponding to the recording density.

FIG. 5 is a block diagram of an example of the device of the present invention, which is an example of an optical disc internal recording device.

In FIG. 5, (6) is an optical pickup section, which includes a laser light source, a lens thread, a light receiving element, etc. Generally, the optical pickup (6) has only these optical systems, but in this example, the optical pickup (6) can be replaced with a pickup compatible with the recording density of the disc, and a playback system that includes a head amplifier and a digital signal extraction section. The circuit (power is incorporated into this optical pickup section (6). This pickup section (
6) scans the recording range portion (5) of the disk (1) in the radial direction from the inner circumference toward the outer circumference.

Normally, the device is initially equipped with a pickup.

The disk (1) is rotated by a rotation mechanism system (8), and a servo circuit (9) is working on this rotation mechanism system (8), and the rotation speed of the disk (1) is determined by this servo circuit (9).
9).

When the disc (1) is loaded into the playback device and the start switch is turned on, the standard speed setting circuit (LD) is activated by the controller (10), its output is supplied to the rotation condition switching circuit (1B), and the servo circuit (1D) is activated. 9) Regardless of the original playback speed of the disc <1), the standard speed (various A rotary machine (1°
4 system (8) is set.

At this time, the optical lift-up part (6) is moved to the disk (1).
), the recording density information, which is converted into a digital signal, is supplied to the reproduction speed determination circuit (13) to detect the appropriate rotation speed of the disc, and the detection output is sent to the rotation condition switching circuit (13). is supplied, and the circus conditions are switched to those when the playback rotation speed is black, which suits the recording history of that Dinuku.

The discrimination circuit (13) also detects 1i information regarding the recording mode in the recording density information, and based on the detection output, which pickup should be used is displayed in the pickup classification display section Oa.

That is, FIG. 4 is a perspective view of the external appearance of the device of this example, in which a pickup storage section (2I) is provided in a part of the cabinet (A). In this example, a standard pickup (6A), a pickup for multilevel signal reproduction (6B) as shown in FIG. 1, and a pickup for multifaceted reproduction (6C) as shown in FIG. It is provided within eD. And each pickup (6N) (6E3) (6
C) Display elements such as lamps LA,
LH and LC are provided.

These lamps LA, LB, [, C constitute a part of the pickup classification display section 04, and are the aforementioned discrimination circuit (13).
), one of the lamps LA, LB, and LC is turned on. In other words, if the result of the determination is that the standard gear angle f (6A) can be left as is, the rung LA lights up, and if not, the rung angle LB lights up.

One of the LC lights up. Then, when either rung LB or LC lights up, the big ring f (6B) or (6C) in that lighted rung position is replaced with the standard big ring f (6A) currently used for squid. It is. In FIG. 4, (2) is a replacement window for the pickup.

When there is no need to replace the pickup, replace the disc (1
) When the playback time of the recorded portion (4) has elapsed, the controller (10) turns off the minimum speed setting circuit 01), and from then on, the servo control is performed according to the output from the birth speed discrimination circuit ([3)]. The rotation of the rotating cedar 111 system (8) is controlled.

In a steady state, the signal train from the pickup (6) is supplied to the program decoder (15), where the digital signal is decoded and outputted to the output terminal (1G). In this case, the program decoder (15) has the function of multiple decoders for multiple pieces of information, but the program decoder (15) is a decoder for program information selected in advance by the creator of the disc according to the size of the disc. It is designed to operate as

In this program decoder (15), when the proper playback rotational speed of the block periodic signal extracted from the -C playback digital signal, etc., the period should be set in advance (the iT number is the speed information detection circuit). (17) and compared with the above-determined cycle standard No. 1,
The comparison error output is supplied to the rotation condition switching circuit (12) to maintain a steady state so that the booth rotates stably at an appropriate reproduction rotation speed'')-yl? 〇Even if pickup 0 is replaced, the program decoder (1ω
11 reproduced output signal sequences are obtained.

Since the reproduction conditions can be changed according to the recording density of the disk as described above, it is possible to easily reproduce discs with a wide variety of recording densities under optimal reproduction conditions at all times.

In addition, in the above example, the servo conditions are changed, but the zergo system is normally set to have the characteristic of following speed changes of about 2 to 3 times without changing the zero conditions. It is possible. However, 7. If you want to be able to play all multi-purpose discs as mentioned at the beginning, you will need to change the speed by more than 10 times. It is difficult to guarantee stable r1 raw speed playback for all these discs without changing system conditions.

In the above example, the reproduction condition is displayed by the output of the discrimination circuit, but it is of course possible to display other 71 raw conditions by this output. For example, it is also possible to display the t1 raw speed IJj and manually change the speed P.

Effects of the Invention As described above, according to the invention, when a predetermined recording density layer is set to the 4441i standard, recording is performed at the recording density of this standard). :
(By using the ff information and distinguishing this 1^ information, it is possible to record a wide variety of recorded sounds) >tl's 1TJ production of the de notarde f-sk. Therefore, this invention d
1. High-density 12' (bamboo) without changing the disc size. It is very effective as a multi-purpose digital disc playback device 1° such as 1715 at the beginning.

Figures 1111 and 2 of the drawings illustrate examples of high-density recording methods. A plan view showing an example of a digital disk as a target, 21st view is a perspective view of an example of the external appearance of the device of the present invention,
FIG. 5 is a block diagram of an example of the essential parts of the apparatus of this invention.

(1) is the preliminary disc, (4) U is the Pj opening candy recording part, (6) is the pickup, LA, LB, LC are the big r tsf (6A) (6B) (6C) It's a lamp.

Claims (1)

[Claims] A device for reproducing a disc on which a digital signal is recorded at a predetermined recording density, and information for identifying the recording density is recorded at the reproduction start position under reproduction conditions of the standard recording density, the apparatus comprising: Only the reproduction 1 start position portion is reproduced under the reproduction conditions of the standard recording density, the recording density identification information is determined, and the output of the determination is used to set the reproduction conditions according to the predetermined recording density. A digital disc playback device that displays a recording density.