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LG Electronics GSA-4168B Reading process of Optical Disc, Focusing, Lens, Groove, Land, Mirror

Models: GSA-4167B GSA-4165B GSA-4168B

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4. Reading process of Optical Disc

3) CD-RW Disc

Label Printing

Protective Layer

Dielectric Layer(TL)

Recording Layer

Dielectric Layer(UL)

Substrate (Polycarbonate)

Laser Beam

Groove

•It is composed of polycarbonate layer, alloy(silver, arsenic) layer, aluminum reflectivity layer, protective layer.

•An crystalized alloy layer is transformed into noncrystalized by the laser heat. Therefore, writing and reading is enabled by the difference of reflectivity.

•It is possible to overwrite about 1000 times.

•Laser Wavelength : 780 nm, Laser Power (Read) : 1.0mW

•Recording Power : Erase (4~18mW), Write (6~45mW)

•When disc rewriting, new data is overwritten previously recorded data.

•Polycarbonate layer has a Pre-Groove which make a track.

4. Reading process of Optical Disc
	Lens	H
		H
	θ	D
	θ
		Beam
		Spot
Focusing	Numerical aperture:	NA=nsinθ,
Lens		n: Refractive index
	Focus depth : H = λ/NA
Laser Spot	laser spot diameter : D = λ/NA2
Laser Spot
at Constant
Read Intensity	Previously Recorded Marks
	Previously Recorded Marks

Reflected

Light

Signal

I3

	Groove	Land	Mirror
I11	IG	IL	I0

Itop Laser Spot

Position (Time)

22

Image 18

LG Electronics GSA-4168B Reading process of Optical Disc, Focusing, Lens, Groove, Land, Mirror, Previously Recorded Marks

Contents

Super Multi DVD Drive P/NO 3828HS1047G August Printed in KoreaSERVICE MANUAL MODEL GSA-4165B GSA-4167B GSA-4168BTABLE OF CONTENTS CAUTION - INVISIBLE LASER RADIATION WHEN OPEN AVOID EXPOSURE TO BEAMINTRODUCTION 1. Support feature and writable disc2. Supported disc formats FEATURES1 General 3. Supported write method4. Performance 5. Audio1x CD = 150 kB/s Recording tool SPECIFICATIONSOperating System 2.1 Applicable disc formats2.4 Data capacity 2.5 RPC Regional Playback Control Phase2, No Region3. DRIVE PERFORMANCE 3.2 Read/Write & Rotational speed3.4 Access time 1/3 stroke 3.3 Data transfer rate2.77, 5.54 Mbytes/s 4. Quality and Reliability 5. POWER REQUIREMENTS8. Dimensions 6. AUDIO PERFORMANCEDrive Activity Indicators LOCATION OF CUSTOMER CONTROLSFront Pane l Drive activity indicatorIDE Interface Connector Rear Pane lAnalog Audio Output Connector Jumper Connector Digital Audio Output Connector2. MECHANISM ASSY DISASSEMBLY DISASSEMBLY1. CABINET and CIRCUIT BOARD DISASSEMBLY Emergency Eject Hole2-2. Pick-up PBF00 FRONT C.B.A EXPLODED VIEWPBM00 MAIN C.B.A LightScribe onlyGLOSSARY Logical EraseMulti session 1. Recording Layer 2. Disc SpecificationThe differences of CD-R/CD-RW discs and General CD-ROM a=30nm2 CD-R disc 3. Disc Materials1 CD-ROM disc PigmentLens Focusing4. Reading process of Optical Disc Groove5. Writing Process of CD-R Disc 6. Writing process of CD-RW DiscAmorphous 7. Organization of the PCA, PMA and Lead-in Area 1 Layout of CD-ROM disc2 Layout of CD-R/RW disc 8. Function of PCA and PMA area 1 PCA Power Calibration Area1 OPC Optimum Power Control 9. OPC and ROPC10. Writing Process of DISC DVD-R/RW Disc LPP Land Pre-Pit DVD+R/RW Disc The differences of DVD-R/RW, DVD+R/RW discs and DVD-ROM0.4 um 1. Recording Layer1 DVD-ROM 2. Disc Specification3. Disc Materials Single Layer2 Recording format using organic dye material DVD-R/DVD+R Disc structureDisc structure Disc structure Recording principlesData erased state N = 3 only the top pulseTtop , first pulse lead-time dT top , dTle 4. Writing Pulse Wave Form of DVD+RNRZI NRZI2 2st Method Using Blocked Write Strategy Channel bits 5. Writing Pulse Wave Form of DVD+RWNRZI Ttop1 Layout of DVD-ROM disc Disc CenterDiameter 120 mm 2 Layout of DVD+R disc3 Layout of DVD+RW disc Disc CenterDiameter 120 mm 1. LightScribe Media DiscOD Label Zone Control Feature Zone Clamping/Logo Zone Center HoleLightScribe Media Screen Printed Imaging Layer Clear Protective CoatingLaser Power Reference Write Strategy Control 2. Hardware Block DiagramLabel Printing SERVO Signals3. MD Assy For LightScribe Optical Encoder UnitOPU ID Movement Range L=21um Encoder PCB Optical Encoder IC Schematic of Enc PCB4. Optical Encoder Assy FFC 3PINCD DATA PROCESSING Data Processing FlowP-up Unit HOP-7632TS R8J32007 2. Copy Protection and Regional Code Management BlockBlock Diagram HOST DVD PLAYER EMPEG2 B/D3. About Prevention the DVD-ROM from to be copy In case of a disc enhanced movie of 3 titlesIf you want to play the disc prevented from the copy 4. About the DVD-ROM Regional Code Regional codeExample The disc manufactured in the U.S.A, has the number one 1. Block Diagram of the PICK-UPHOP-7632TS INTERNAL STRUCTURE OF THE PICK-UP2. Pick up Pin Assignment Signal NameSignal Description Tp/2 3. Signal detection of the P/UTrack Center MainCN101 CIRCUITDESCRIPTION OF 1. ALPC Automatic Laser Power Control CircuitIC301 R8J32007 IC101 R2S350021-2. ALPC Automatic Laser Power Control Circuit R2S35002 2. Focus CircuitIC101 DiscR2S35002 3. Tracking & Sled CircuitIC101 DiscDisc IC101R2S35002 Optical3-2-1. Tracking Servo 3-2-2. Sled ServoOptical 4. Spindle Circuit4-1-1. Block DiagramFGCAV Servo Pick-upCD-RW 4x, 10x, 16x, 24x DVD-R 2x, 4x, 8x, 16xPCAV DVD-R DL 2x 4-2-1. Block Diagram Wobble CLV Servo4-2-2. Wobble CLV Servo CD-R 4x, 8x, 16x, 24x, 32x DVD-RW 1x, 2x, 4x DVD+R 2.4x, 4x, 8x, 12x, 16xPCAVR2S35002 IC101 R2S35002 RF AMP Analog Signal ProcessorMAJOR IC INTERNAL BLOCK DIAGRAM AND PIN DESCRIPTION TOP VIEWPick BALANCEpin No Pin Functionspin Name Typepin No Equalizer fc auto-adjustment control clock input terminalpin Name TypeType pin Namepin No max. voltageIC301 R8J32007FPV Encoder, Decoder & DSP Singal Processor Top ViewR8J32007 1.2 Block Diagram DemodulateDescramble Pin Name 1.3 Pin TablePin no Pin noPin No Data PLL/PRML Pin ListPin Name destinationPin No Servo Pin ListPin Name destinationPin No ATAPI Interface Pin ListPin Name destinationPin No Encoder Interface Pin ListPin Name destinationPin No Audio Interface Pin ListPin Name destinationPin No LSI/TEST Control Pin ListPin Name destinationPin No Power Supply/GND Pin ListPin Name FunctionIC601 R2S30202FP SPINDLE MOTOR AND 6CH ACTUATOR DRIVER Package outline 42 PIN POWER SSOP 42P9R-KR2S3 0202FP Page Input/Output circuit diagram 02 High Frequency/NRZI skew Adjust TROUBLESHOOTING GUIDE01 Laser Power Adjust using RD Power/WR Power/Erase Power 03 Data Slice/Equalizer Boost/Raw Slice/ Equalizer Frequency Adjust06 Focus Amp. and Total Amp. Adjust 07 Tracking Amp. Adjust08 Servo Loop Gain Adjust 11 Focus Offset Adjust for DVD-RAM PID Amp 09 Unwritten Slice Level Adjust for DVD-RAM10 Focus Offset Adjust for DVD-ROM, CD-R/RW 12 Focus Offset Adjust for DVD-RAM Data Error pulse15 Focus Deviation Adjust 13 Tilt Adjust for DVD-RAM14 Tilt Adjust for DVD-R/RW, DVD+R/RW, CD-R/RW 16 Focus Offset Adjust for DVD-R/RW, DVD+R/RW, CD-R/RW19 ADIP BPF/Read Timing Adjust for DVD+R/RW 17 Lens Sensitivity Adjust18 Spindle Offset Adjust 20 Focus Offset Adjust for DVD-R/RW, DVD+R/RWDIDAll Disc 21 RTZ TimeOut Fail22 Focus Servo/Tracking Servo Fail Slider#6,8-10Detail Error Code & Fail Analysis 1. Laser Power Initial Adjust SSB Byte8,92. Adjusting Error during Disc Load Sequence Lead in Error SSB Byte21,22SSB Byte21,22 SSB Byte21,22 SSB Byte21,22 3. Loading Sequence Error Lead in Error SSB Byte21,22SW701 JR6 Power Supply System Diagram5V in SW702 IC701PCB Poor Analysis - Check list HW Self- Diagnostic function 1. Self-Diagnostic Function by LED Blink 2 Does the power supply circuit operate normally? 3 Is the clock of MPU in DSP oscillated correctly?4 The defect of Flash-ROM 1 IC601R2S30202FP 7ch driver A control mode setup by the control terminal3. Motor, Abnormalities in Actuator System A motor & actuator and its correspondence pin12V GND 5V BLOCK DIAGRAMHost IDE OPUHOP-7632TS HITACHI ME