KR100256642B1 - Method and apparatus for detecting a disk is exist or not in a disk tray for use in a digital video disk player - Google Patents

Abstract

PURPOSE: Deciding device and method for existence of a disk in a DVDP(Digital Video Disk Player) are provided to precisely decide existence of the disk through increasing reflecting amount by increasing output of a laser diode in case of a small optical amount. CONSTITUTION: An optical pickup unit(10) contains a laser diode to perform focus servo to pick up beam outputted from the laser diode and reflected on a disk(D). An optical amount detect unit(20) detects optical amount of beam from the optical pickup unit. A compensate unit(40) outputs a compensating signal for compensating a focus error. A pickup drive unit(50) drives the optical pickup unit to perform focus servo. A microcomputer(60) compares the optical mount signal with a reference signal for increasing output of the laser diode by the optical amount signal lower than the reference. A laser diode drive unit(70) increases output of the laser diode according to the microcomputer.

Description

Discrete device and method for disc presence of digital video disc player {METHOD AND APPARATUS FOR DETECTING A DISK IS EXIST OR NOT IN A DISK TRAY FOR USE IN A DIGITAL VIDEO DISK PLAYER}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for determining the presence or absence of a disc in a digital video disc player, and more particularly, to an apparatus and method for determining the presence or absence of a disc in a digital video disc player using the amount of light reflected from the disk surface. .

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 to 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 It is able to provide sound quality, no noise caused by irregular playback and modulation, low distortion, no ghost (virtual), random access, etc. have.

In addition, such an optical disk player includes a compact disk player (CDP: compact disk player), a laser disk player (L: laser disk player), a compact disk graphic player (CDGP: compact disk graphic player), and a video compact disk player (VC). For example, a video compact disk player has been developed and widely used. 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 is capable of recording and playing back gigabytes (GB) of data including moving images on a 12cm optical disc like a current CD, and is designed to be compatible to play current CDs and VCDs.

On the other hand, the above-described digital video disc player can also play CDs and VCDs. In order to perform playback on a predetermined disc in the digital video disc player, first, disc chucking is performed and then 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 to determine the presence and type of a disc, and then detects whether or not the data to be reproduced is processed smoothly. Is configured to determine.

By the way, the wavelength of 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 laser diode for DVD is used for the VCD and the CD, there is a problem that the level of the reflected light is weak and it can 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.

In order to achieve this object, the present invention provides a disc for disc presence determination apparatus of a digital video disc player for determining whether a disc has been chucked when disc chucking is performed to reproduce a disc, wherein a disc has a predetermined level of light. An optical pick-up unit having a laser diode provided to pick up and output a light reflected from the disk by executing a focus servo when chucking is performed on a predetermined disk; A light amount detector for detecting a light amount of reflected light provided from the optical pickup unit; A compensating unit for detecting a focus error from the light quantity signal detected by the light quantity detecting unit and outputting a compensation signal for compensating for this, and outputting a focus O.K signal when a focus servo is performed; A pickup driver for driving the optical pickup unit according to the compensation signal of the compensator to perform a focus servo; Compares the light quantity signal provided from the light quantity detector with a preset reference level signal, and outputs a control signal for increasing the output of the laser diode when the light quantity signal is smaller than the reference level signal. When the focus OK signal is provided from the compensator, the disk ' A microcomputer that recognizes the name 'Yes'; It is provided with a laser diode driver for driving in accordance with the control signal of the microcomputer to increase the output of the laser diode.

The present invention also provides a disc presence determination method of a digital video disc player for determining whether a disc is chucked when disc chucking is performed to play a predetermined disc. Performing focus if a predetermined disc is chucked, detecting a quantity of light reflected from the disc, and comparing the detected amount of light with a preset reference level signal; I. Comparing the reflected light amount with the reference level while increasing the output of the laser diode for executing the optical pickup from the disk by a predetermined number of times if the reflected light amount is less than the reference level in step (a); All. If the amount of reflected light is greater than or equal to the reference level in step (a) or (b) and the focus servo is performed, the chucked disk is determined to be 'yes'. Equipped.

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.

<Description of the code | symbol about the principal part of drawing>

10: optical pickup unit 20: light quantity detection unit

30: focus error detection unit 40: compensation unit

50: pickup drive unit 60: microcomputer

70: LD drive unit 75: power supply unit

80: RF amplifier D: disk

R _T : Variable resistor

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. And 70. In addition, in FIG. 1, the RF amplifier 80 amplifies and outputs a radio frequency (RF) signal that is picked up by the optical pickup unit 10 and provided through the light quantity detector 20, and this output signal is generally well known. As such, it is provided to and processed by a digital signal processing unit (not shown).

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

In addition, the focus error detector 30 may detect the focus error signal based on the amount of light detected by the light amount detector 20 and provide the same to the compensator 40. Meanwhile, the compensator 40 outputs a compensation signal for compensating the focus error signal provided from the focus error detector 30, and when the focus servo is performed, the focus O.K. Provide a signal to the microcomputer 60.

The pickup driver 50 drives the optical pickup unit 10 in the up or down direction so that the focus servo is driven by driving in accordance with the compensation signal provided from the compensator 40.

The microcomputer 60 receives the focus O.K. from the compensator 40 when performing the focus servo. When the signal is provided, it recognizes that the focus servo has been made. Also, if the focus OK signal is provided when the focus servo is performed to determine whether or not the disk is present, it is determined that the disk is 'yes', and the light quantity signal provided from the light quantity detection unit 20 The laser driver 70 provides a control signal for increasing the output of the LD when the light quantity signal is smaller than the preset reference level, that is, the minimum light quantity signal level capable of disc presence determination.

The laser driver 70 includes a variable resistor R _T and a power supply 75, and is driven under the control of the microcomputer 60 so that the LD outputs a predetermined level of light onto a disk. That is, the laser 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 executing 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 laser driver 70 varies the resistance value of the variable resistor R _T under the control of the microcomputer 60 to vary the output current of the power supply unit 75, thereby varying the current applied to the LD. The level of the output light of the LD is changed.

On the other hand, the optical pickup section 10, as is well known in the art, a laser diode (LD: not shown), a polarizing beam splitter (not shown), and a quarter wave plate (not shown) and And an objective lens (not shown), the optical pickup is performed on the predetermined disk D to provide the light amount 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 a key input unit (not shown) to perform disk chucking on a disk tray (not shown), the laser driver 70 is driven and controlled by the microcomputer 60. The LD constituting the pickup section 10 outputs the light of the initial reference level for disc presence determination. Accordingly, the optical pickup section 10 picks up the light reflected from the disk D, and thus the light amount detection section 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.

The focus error detector 30 detects a focus error from the light quantity signal detected by the light quantity detector 20, and provides a pickup signal to the pickup driver 50 to compensate for the focus error. When the detection of the loss, the microcomputer 60 provides a focus OK signal.

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 perform the focus servo.

On the other hand, the microcomputer 60 compares the light quantity signal provided from the light quantity detector 20 with a 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 determined. By supplying a control signal for increasing the laser drive unit 70 to reduce the resistance value of the variable resistor (R _T ) to increase the current value provided to the LD from the power supply unit 70 to increase the output power of the LD, At this time, the output power of the LD is gradually increased for a predetermined 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 '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, if the light amount signal of the light detector 20 is smaller than the preset reference level signal, it recognizes that the disk 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 according to a predetermined key signal, for example, a 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 operation 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.

When the process proceeds to step S50 in step S40, 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 the process proceeds to step S60. . 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, the number of times the power rise of the laser output light is compared with the reference number, for example, three times, if the number of times the output power is used is less than the reference number again. 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, whether focus servo is performed in step S80, that is, as described with reference to 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, when the wavelength of the laser used for DVD playback in a digital video disc player is very small due to the short wavelength of the laser used to play CDs and VCDs, By increasing the output power of the laser diode, the size of the reflected light is raised to a level at which the disc can be discriminated, so that not only the disc is discriminated but also the disc type can be determined.

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 device of the digital video disc player to determine whether there is a chucked disc (D) when disc chucking is performed to play a predetermined disc (D), When a chucking is performed for the predetermined disk D by providing a laser diode that provides 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 outputting a compensation signal for compensating for this, and outputting 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; The light amount signal provided from the light amount detector 20 is compared with a preset reference level signal to output a control signal for increasing the output of the laser diode when the light amount signal is smaller than the reference level signal, and the compensation unit 40 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) for driving according to the control signal of the microcomputer (60) to increase the output of the laser diode. The method of claim 1, 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 to thereby change the power supply 75. Discrete device for disc presence of a digital video disc player, characterized in that the output power of the laser diode is varied by varying the amount of current applied to the laser diode. The method of claim 1, The reference level signal preset in the microcomputer (60) is a disc presence determination device of the digital video disc player is a minimum light quantity signal capable of disc presence determination. 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 when the reflected light amount is less than the reference level in step (a). Wow; (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 referred to in step (b). Determining whether the disc is 'no' if less than the level.

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