KR19980078975A - Disc and Discrimination Device and Method of Digital Video Disc Player - Google Patents

Abstract

The present invention relates to an apparatus and method for determining the presence or absence of a disc in a digital video disc player. Wow; (B) comparing the reflected light amount with the reference level while increasing the output of the laser diode for performing optical pickup from the disk by a predetermined number of times if the reflected light amount is less than the reference level in the step (a); ; (C) If the reflected light amount is greater than or equal to the reference level in step (a) or (b) and the focus servo is performed, it is determined that the chucked disk is 'y' and the reflected light amount is greater than the reference level in step (b). And if it is small, determining that the disk is 'no'.

Therefore, the present invention has an effect of preventing an error due to disc presence or absence that occurs due to a weak reflected light in a digital video disc player.

Description

Disc and Discrimination Device and Method of Digital Video Disc Player

The present invention relates to an apparatus and method for determining the presence or absence of a disc in a digital video disc player. In particular, the present invention relates to a digital video disc that makes it possible to discriminate disc presence even when the disc presence cannot be determined because the amount of light reflected from the disc surface is weak. An apparatus and method for determining the presence or absence of a disc in a disc player.

With the development of audio and video media, optical disc players for recording and reproducing video and audio data on semi-permanent optical discs have been developed.

Such an optical disc player reproduces an image and / or audio recorded on an optical disc and outputs it through a screen and / or a speaker, and has a higher signal-to-noise ratio than conventional image and / or audio reproducing apparatus, resulting in better image quality and / or Or it can reproduce the signal with sound quality, it does not generate noise due to irregular reproduction and modulation, very low distortion, no ghost and random access, so it is rapidly developed and widely distributed. There is a trend.

In addition, such an optical disk player includes a compact disk player (CDP), a laser disk player (LDP), a compact disk graphic player (CDGP), and a video compact disk player (VCDP: video compact disk player) has been developed and widely used. Also, recently, a digital video disk (DVD) using MPEG-2 moving picture compression technology and a digital video disk player for playing the same have been developed. It can record and play back gigabytes (GB) of data including moving images on a 12cm optical disc such as a CD, and it is also designed to be compatible to play current CDs and VCDs.

On the other hand, a digital video disc player as described above can also play CDs and VCDs. In order to perform playback on a predetermined disc in a digital video disc player, first, disc chucking is performed and then the focus servo is executed. It is configured to determine the presence or absence, thereafter play the disc to determine the type of the disc, and set the play mode according to the determined disc type to execute the play.

In addition, the digital video disc player first determines the presence or absence of a disc by executing a focus servo using a DVD pickup in order to determine the presence and type of a disc, and then detects whether or not the data to be reproduced is processed smoothly to determine the type of disc. Configured to determine.

By the way, the wavelength of the light generated by the laser diode used for the pickup for DVD (about 635 ηm) is shorter than the wavelength of the laser diode for the general VCD and CD (about 7855 ηm). Since the amount of light decreases, when the DVD laser diode is used for the VCD and the CD, there is a problem that the level of the reflected light amount is weak and it may be determined that there is no disk.

Accordingly, the present invention has been made to solve such a problem in the related art, and an object of the present invention is to determine the presence or absence of a disc in a digital video disc, thereby increasing the output of the laser diode when the amount of light reflected from the disc is weak. The present invention provides an apparatus and method for determining the presence or absence of a disc in a digital video disc player which can more accurately determine the presence or absence of a disc.

According to a preferred embodiment of the present invention for achieving the above object, in the disc chucking device of the digital video disc player for determining whether there is a chucked disc when the disc chucking to play a predetermined disc, The optical pickup unit which includes a laser diode for generating a predetermined level of light to the disk and performs chucking on the predetermined disk to perform focus servo to pick up and output the light generated by the laser diode and reflected from the disk. And a light amount detector for detecting a light amount of the reflected light provided from the optical pickup unit, generating a compensation signal for detecting and compensating a focus error from the light amount signal detected by the light amount detector, and focusing when the focus servo is performed. Compensation unit for generating a signal, and A pickup driving unit for driving the optical pickup unit according to an upper compensation signal to perform a focus servo, and when the focus OK signal is provided from the compensating unit, recognizing that the disk is 'yes', The microcomputer generates a control signal for increasing the output of the laser diode when the light quantity signal is smaller than the reference level signal compared to a preset reference level signal, and is driven according to the control signal of the microcomputer to output the laser diode output. It includes and is configured to increase the laser diode.

According to another preferred embodiment of the present invention for achieving the above object, in the disc presence determination method of the digital video disc player to determine whether there is a chucked disc when disc chucking is performed to play a predetermined disc, A) performing a focus when a predetermined disk is chucked, detecting the amount of light reflected from the disk and comparing it with a preset reference level signal; and (b) in step (a), the amount of reflected light is less than the reference level. Comparing the reflected light amount with the reference level while increasing the output of the laser diode for performing the optical pickup from the disk by a predetermined number of times; and (c) the reflected light amount in the step (a) or (b). The chucked disc is greater than or equal to a reference level and the focus servo is performed. Determines that the "U" and comprising the step of determination that is less than the above-mentioned (B) based on the quantity of reflected light level in step the disc is 'no'.

1 is a block diagram of a disc presence determining apparatus of a digital video disc player according to an embodiment of the present invention;

2 is a flowchart illustrating a disc presence determination method of a digital video disc player according to an exemplary embodiment of the present invention.

* Explanation of symbols for main parts of drawings *

10: optical pickup unit 20: light quantity detection unit

30: focus error detection part 40: compensation part

50: pickup drive unit 60: microcomputer

70: LD drive unit 75: power supply unit

80: RF amplifier D: disk

R _T : Variable resistance

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram showing a disc presence determination apparatus of a digital video disc player according to the present invention.

As shown in FIG. 1, the present invention includes an optical pickup unit 10, a light amount detector 20, a focus error detector 30, a compensator 40, a pickup driver 50, a microcomputer 60, and a laser driver. It comprises 70 and is comprised. In addition, in FIG. 1, the RF amplifier 80 amplifies and outputs an RF (radio frequency) signal that is picked up by the optical pickup unit 10 and provided through the light quantity detector 20, and this output signal is typically well received. As is known, it is provided to a digital signal processor (not shown) for digital signal processing.

The optical detector 20 detects an amount of light of the optical signal provided from the optical pickup unit 10 and provides the optical error to the focus error detector 30.

In addition, the focus error detector 30 detects a focus error signal based on the amount of light detected by the light amount detector 20 and provides the same to the compensator 40. Meanwhile, the compensator 40 generates a compensation signal for compensating the focus error signal provided from the focus error detector 30. In this case, when the focus servo is performed, the focus O.K. The signal is generated by the microcomputer 60.

The pickup driver 50 is driven according to the compensation signal provided from the compensation unit 40 to transfer the optical pickup unit 10 upward or downward so that the focus servo is performed.

The microcomputer 60 receives the focus O.K. from the compensator 40 when the focus servo is executed. When the signal is provided, it recognizes that the focus servo has been made. Also, if the focus OK signal is provided during the execution of the focus servo for disc presence / absence discrimination, it is determined that the disc is 'yes', and the light quantity signal provided from the light quantity detector 20 is preset. When the light quantity signal is smaller than the preset reference level compared to the reference level, that is, the minimum light quantity signal level at which the disc can be discriminated, the LD driver 70 generates a control signal for increasing the output of the LD.

The LD driving unit 70 includes a variable resistor R _T and a power supply unit 75, and is driven under the control of the microcomputer 60 so that the LD outputs a predetermined level of light onto the disk. That is, the LD driver 70 is driven under the control of the microcomputer 60 so that the LD outputs a predetermined level of light, and outputs a reference optical signal for performing optical pickup from the DVD disc during the initial operation. When the amount of light reflected from the disk D is smaller than the reference level preset by the microcomputer 60, the drive is performed to increase the output of the LD. In other words, the LD driving unit 70 varies the resistance value of the variable resistor R _T according to the control of the microcomputer 60 to change the output current of the power supply unit 75, and accordingly, the current applied to the LD varies and thus LD. The level of the light output changes.

On the other hand, the optical pickup unit 10 is a laser diode (LD: not shown), a polarizing beam splitter (not shown), a quarter wave plate (not shown), as is well known in the art And an objective lens (not shown) to perform optical pickup for the predetermined disk D to provide the light quantity detector 20 with the light reflected and picked up on the disk.

Referring to the operation of the disk presence determination apparatus according to the present invention configured as described above are as follows.

When a predetermined function key signal is input from the key input unit (not shown) and disk chucking is performed on the disk tray (not shown), the LD driver 70 is driven under the control of the microcomputer 60 to provide light. The LD constituting the pickup unit 10 outputs light of an initial reference level for disc presence determination, and accordingly, the optical pickup unit 10 picks up the light reflected from the disc D, and thus the light amount detection unit 20. To provide. That is, when the chucking of the predetermined disk D is performed, the optical pickup unit 10 executes a focus servo, picks up the light reflected from the laser diode, and outputs the light reflected from the disk D to the light amount detector 20. do. Then, the light detector 20 detects the amount of light reflected from the optical pickup unit 10 and provides it to the focus error detector 30 and the microcomputer 60.

Accordingly, the focus error detector 30 generates a compensation signal to the pickup driver 50 to detect and compensate the focus error from the light quantity signal detected by the light quantity detector 20, and focus servo signal through the detected focus error signal. Is detected, a focus OK signal is generated to the microcomputer 60.

Accordingly, the pickup driver 50 is driven according to the compensation signal of the compensator 40 to drive the optical pickup unit 10 in the up or down direction to achieve the focus servo.

On the other hand, the microcomputer 60 compares the light quantity signal provided from the light quantity detector 20 with the preset reference level signal and outputs the LD when the light quantity signal is smaller than the reference level signal, that is, the minimum light quantity signal level at which the disc can be discriminated. Generating a control signal to increase the output power of the LD by increasing the current value supplied from the power supply unit 70 to the LD by generating a control signal for increasing the resistance of the variable resistor R _T. At this time, the output power of the LD is gradually increased for a preset number of times according to the preset level, but only to the extent that the LD output power does not damage the disk.

In addition, the microcomputer 60 recognizes that the disk is 'yes' when the focus OK signal is provided from the compensator 40 through the above-described process, and also increases the output level of the LD, that is, the output power to the maximum setting value. Nevertheless, when the light quantity signal of the light detector 20 is smaller than the preset reference level signal, the disc recognizes that the disc is 'no'.

As described above, when disc presence is determined according to the present invention, if disc 'yes', the microcomputer 60 performs playback to determine the type of disc according to the signal processing state in the digital signal processing unit (not shown). In this way, playback can be performed by setting the playback mode according to the disc type determined.

2 is a flowchart illustrating a disc presence determination method of a digital video disc player according to another exemplary embodiment of the present invention.

When the disc is chucked to the disc tray in accordance with a predetermined key signal, for example, the reproduction key signal in step S10, the focus servo is executed in step S20, and reflected on the disc in step S30. The amount of light of the picked-up light is detected.

In step S40, the reflected light amount is compared with a preset reference level signal, that is, a minimum light amount signal capable of disc presence determination. If the reference level signal is larger than the reflected light amount signal, the operation proceeds to step S50. If the reflected light amount signal is greater than or equal to the reference level signal, the process proceeds to step S80.

First, in step S40 to step S50, in step S50, the output power of the LD constituting the optical pickup unit 10 as shown in FIG. 1 is increased by a predetermined level, and in step S60, Proceed. Then, in step S60, the reflected light amount is compared with the preset reference level signal according to the output light which has risen again. If the reference level signal is larger than the reflected light amount signal in step S60, the process proceeds to step S70. If the reflected light amount signal is greater than or equal to the reference level signal, the process proceeds to step S80.

On the other hand, when the process proceeds from step S60 to step S70, in step S70, if the number of times of output power is smaller than the reference number is compared again, the number of times of power rise of the laser output light is compared with the reference number, for example, three times. The flow returns to step S50 to repeat the flow, and if greater than or equal to S50, the flow advances to step S90 to determine that the disc is 'no' and the flow ends.

On the other hand, if the process proceeds from step S40 or step S60 to step S80, the focus servo is performed in step S80, that is, as described in FIG. 1, the focus O.K. To determine whether a signal is provided, if the focus servo is made in step S80, the flow returns to step S30 to redo the flow, and if the focus servo is made, it is determined in step S100 that the disk is 'Y' and the flow ends. do.

As described above, the present invention provides that when the wavelength of the laser used for DVD playback in a digital video disc player is very small, the amount of light reflected from the VCD or CD due to the short wavelength of the laser used for playing the CD and VCD, By increasing the output power of the laser diode, the size of the reflected light is raised to a level at which discs can be discriminated, so that not only discs can be discriminated but also disc types can be desired.

As described above, the present invention has an effect of preventing an error due to disc presence or absence that occurs due to weak reflected light in a digital video disc player.

Claims (4)

In the disc presence determination apparatus of the digital video disc player to determine whether there is a chucked disc when disc chucking is performed to play a predetermined disc (D), When the chucking is performed for the predetermined disk D by providing a laser diode for generating a predetermined level of light to the disk D, a focus servo is executed to be output from the laser diode and reflected from the disk D. An optical pickup unit 10 for picking up and outputting light; A light amount detector 20 for detecting a light amount of reflected light provided from the optical pickup unit 10; A compensation unit 40 for detecting a focus error from the light amount signal detected by the light amount detection unit 20 and generating a compensation signal for compensating for this, and generating a focus O.K signal when a focus servo is performed; A pickup driver 50 for driving the optical pickup unit 10 according to the compensation signal of the compensation unit 40 so as to perform a focus servo; When the light quantity signal is smaller than the reference level signal by comparing the light quantity signal provided from the light quantity detector 20 with a preset reference level signal, a control signal for increasing the output of the laser diode is generated. A microcomputer 60 recognizing that the disk is 'yes' when the focus OK signal is provided from the input signal; And a laser diode driver (70) which is driven according to the control signal of the microcomputer (60) to increase the output of the laser diode. 2. The laser diode driver of claim 1, wherein the laser diode driver 70 includes a variable resistor R _T and a power supply 75, and the resistance value of the variable resistor R _T is variable according to the control of the microcomputer 60. The disc presence determination device of the digital video disc player, characterized in that the output power of the laser diode is varied by varying the amount of current applied from the power supply unit (75) to the laser diode. The apparatus of claim 1, wherein the reference level signal preset in the microcomputer (60) is a minimum light quantity signal capable of discriminating the presence or absence of a disc. In the disc chucking method of the digital video disc player for determining whether there is a chucked disc when the disc chucking is performed to play a predetermined disc, (A) performing focus if a predetermined disk is chucked, detecting an amount of light reflected from the disk, and comparing it with a preset reference level signal; (B) comparing the reflected light amount with the reference level while increasing the output of the laser diode for performing optical pickup from the disk by a predetermined number of times if the reflected light amount is less than the reference level in the step (a); ; (C) If the reflected light amount is greater than or equal to the reference level in step (a) or (b) and the focus servo is performed, it is determined that the chucked disk is 'y' and the reflected light amount is greater than the reference level in step (b). Determining whether the disc is 'non' if it is small.