baber/WOPTO huggingface dataset:
Patent KR-20030056305-A (KR)
Title: A wavelength assignment apparatus in wdm optical ring networks and an algorithm therefor
Inventor: CHA JAE SEON
IPC: H04B10/2581
Filed: 2001-12-28
Abstract: PURPOSE: An apparatus for assigning a wavelength in a WDM(Wavelength Division Multiplexing) ring-type optical network and a method therefor are provided to dynamically assign the wavelength according to the state of the network in consideration of a sparse wavelength conversion and a limited wavelength conversion. CONSTITUTION: A node unit(30) has a plurality of nodes, and receives a call setup request from the outside. A wavelength assignment control unit(20) connects to the node unit(30), and calculates usable paths between the nodes by a sparse wavelength conversion and a limited wavelength conversion, when the call setup request is generated. The wavelength assignment control unit(20) calculates the total number of gaps per usable path, and assigns a wavelength to a path with the minimum total number of the gaps.
Patent KR-20030059550-A (KR)
Title: Method for operating thin film transistor lcd
Inventor: KIM UK SEONG
IPC: G09G3/20
Filed: 2001-12-29
Abstract: PURPOSE: A method for driving a thin film transistor liquid crystal display is provided to prevent the quality of a picture from deteriorating by preventing motion blur, and minimize light loss by providing cooling time to a back light unit. CONSTITUTION: An actual data block and a black data block are designated in each frame. Pixels are driven by applying a first gate signal to the actual data block and applying a second gate signal to the black data block to apply data signals according to the gate signals. A back light unit(15) is made up of an upper light emitting element(15a) and a lower light emitting element(15b) to emit the pixels. If a signal block(300) by the second gate signal exists at an upper part of a screen, only the lower light emitting element is turned on. If the signal block exists at a lower part of the screen, only the upper light emitting element is turned on. If a ratio of the signal block by the second gate signal is larger than a ratio of the signal block by the first gate signal, only the light emitting element mounted at a part where the signal block by the second signal is little is turned on.
Patent KR-20010083091-A (KR)
IPC: C07C323/60
Filed: 1999-06-25
Abstract: 본 발명은, 예를 들어 고혈압, 협심증, 심부전증, 혈전증 또는 아테롬성 동맥경화증과 같은 심혈관 질환을 치료하고 예방하는데 있어 유용한 약제학적 활성 화합물인 화학식 Ⅰ의 화합물에 관한 것이다. 
     화학식 Ⅰ 
     
       
     
     상기식에서, 
     A 1 , A 2 , R 1 , R 2 , R 3 , X 및 n은 본문에서 기술한 바와 같다. 
     화학식 Ⅰ의 화합물은 사이클릭 구아노신 모노포스페이트(cGMP)의 체내 생성을 조절할 수 있고 cGMP 균형 파괴와 관련된 질환을 치료하고 예방하는데 일반적으로 적합하다.  본 발명은 또한 화학식 Ⅰ의 화합물의 제조방법, 상기한 질환을 치료하고 예방하기 위한 이의 용도, 상기한 목적의 약제를 제조하기 위한 이의 용도, 및 화학식 Ⅰ의 화합물을 함유하는 약제학적 제제에 관한 것이다.
Patent KR-20010071827-A (KR)
Title: 반점성망막 퇴행에서 신혈관 신생의 예방치료
IPC: A61K31/58
Filed: 1999-07-12
Abstract: 본 발명은 적절한 항-염증제를 (안구의)유리질(the vitreous)내에 도입함으로써 반점성망막 퇴행에서 맥락막 신혈관 신생의 예방에 관한 것이다. 보다 상세하게, 본 발명은 맥락막 신혈관 신생 발생의 고위험을 갖는 것으로 확인된 눈에서 화학식 (I)의 11-치환된 16α,17α-치환된 메틸렌디옥시 스테로이드와 같은 항-염증 스테로이드를 이용한 신혈관 신생의 예방에 관한 것이다. 
     
       
     
     단, 상기 식에서 (a)는 (b), (c), (d), (e), (f), (g), (h), (i), (j), (k) 또는 (l)이며; R 1 및 R 2 는 수소 및 알킬이며; -C a -C b -는 -CH 2 -CH 2 -, -CH=CH-, (m) 또는 (n)이며; R 3 는 메틸, 히드록시메틸 또는 알킬카보닐옥시메틸, 메틸아미노알킬렌카보닐옥시메틸, 또는 페닐아미노알킬렌카보닐옥시메틸이며; R 4 는 알카노일이며; 그리고 X는 할로겐이다. 특히, 본 발명은 트리암시놀론 아세토니드(화합물 II)를 이용한 예방에 관한 것이다.
Patent KR-20010072429-A (KR)
IPC: C07B61/00
Filed: 1999-07-28
Abstract: The present invention relates to a new class of peroxides and to a process for the preparation of these peroxides having the general formula (I),wherein n=1 or 2, R1, R2, R4, R5, and R6 are independently selected from the group comprising hydrogen, C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C7-C20 aralkyl, and C7-C20 alkaryl, or R1 and R2 form a C3-C12 cycloalkyl group, which groups may include linear or branched alkyl moieties; and each of R1, R2, R4, R5, and R6 may optionally be substituted with one or more groups selected from hydroxy, alkoxy, linear or branched alkyl, aryloxy, halogen, ester, carboxy, nitrile, and amido, and R1 and R2 may form a ring, andR3 is independently selected from the group comprising C1-C20, alkyl; C3-C20 cycloalkyl, C6-C20 aryl, C7-C20, aralkyl, and C7-C20 alkaryl, which groups may include linear or branched alkyl moieties; and R3 may optionally be substituted with one or more groups selected from hydroxy, alkoxy, linear or branched alkyl, aryloxy, halogen, ester, carboxy, nitrile, and amido, and any pair of the optionally substituted R3, R4, R5, and R6 may form a ring, comprising the reaction of the corresponding ketone.
Patent KR-20010083888-A (KR)
IPC: G03H1/24
Filed: 1999-08-19
Abstract: 검증 가능한 홀로그래픽 제품(1)은 적어도 하나의 홀로그램(10)과 얼라이어싱 효과 또는 모아레 효과를 발생하는 디코딩 샘플링 장치, 예컨대 사진 복사기를 이용하여 비위장 이미지로 변환 가능한 적어도 하나의 위장 이미지를 포함하는 기판(5)으로 이루어져 있다. 제품은 "제1선" 및 "제2선"의 보증 특성을 가격 효과적으로 제공하며, 쉽고, 신속하고, 안전하게 검증 또는 인증될 수 있다.
Patent KR-20010089291-A (KR)
Title: Method for inserting a pumping rod in a discharge chamber
IPC: H01J9/26
Filed: 2000-07-28
Abstract: In a novel method in the field of the production of discharge vessels, in particular for silent flat radiators, an exhaust tube 3 for evacuating and filling is inserted into an opening 2 in the discharge vessel, it being possible in a simple way by means of an adapter 4 to achieve optimum fitting and sealing between a square inner cross section of the opening 2 and a round outer cross section of the exhaust tube 3.
Patent KR-20010080198-A (KR)
IPC: B32B37/15
Filed: 2000-06-15
Abstract: 본 발명은 하도 처리를 실시하지 않거나, 또는 오존으로 압출 적층된 수지의 용융된 필름을 처리하지 않고 폴리에스테르 필름상에 직접 수지를 압출 적층시켜 얻은 층간 접착력이 우수한 적층된 필름을 제공한다. 적층된 필름은 폴리에스테르 필름상에, 밀도가 840∼900 kg/cm 3 인 에틸렌/α-올레핀 공중합체 소량과 추가로 배합할 수 있는 불포화된 카르복실산 및 (메트)아크릴산 에스테르를 함유하는 에틸렌 공중합체를 압출 적층시켜 얻으며, 상기 불포화된 카르복실산 성분의 양은 1∼12 중량%이고, (메트)아크릴산 에스테르 성분의 양은 2∼25 중량%이다.
Patent KR-20010103701-A (KR)
IPC: A23G3/34
Filed: 1999-11-02
Abstract: 제과 베이스, 및 제과 조성물내에 충분한 비점착성 도메인을 제공하기에 유효한 양의 불용성 및 가용성 성분의 혼합물을 포함하는 비점착성 제과 조성물이 개시된다.
Patent KR-20010101006-A (KR)
Title: Device for storing disc-shaped data carriers
IPC: G11B23/03
Filed: 1999-11-12
Abstract: The present invention relates to a device for storing disc-shaped data carrier mainly of the CD or DVD type, wherein said device comprises a coupling member which is designed so as to maintain the data carrier and which can be removably connected to said carrier.
Patent KR-20010108029-A (KR)
Title: Field effect transistor arrangement with a trench gate electrode and an additional highly doped layer in the body region
IPC: H01L29/423
Filed: 1998-12-18
Abstract: A field effect transistor configuration with a trench gate electrode and a method for producing the same. An additional highly doped layer is provided in the body region under the source. The layer is used for influencing the conductibility of the source or the threshold voltage in the channel region. Breakdown currents and latch-up effects can thereby be prevented.
Patent KR-20010101723-A (KR)
Title: Process for the preparation of α-aminoketones
IPC: C07C269/04
Filed: 2000-01-28
Abstract: An amino group of an  alpha -amino acid ester is protected as an imine, and it is then reacted with a halomethyllithium to obtain an N-protected- alpha -aminohalomethylketone. Further, this N-protected- alpha -aminohalomethylketone is treated with an acid to obtain an alpha -aminohalomethylketone. This process is suited for industrial production, and can produce an  alpha -aminohalomethylketone and its related compounds economically and efficiently.
Patent KR-20010101775-A (KR)
Title: Therapeutic compositions containing glutathione analogs
IPC: C07K5/093
Filed: 2000-01-27
Abstract: Pharmaceutical compositions and methods of using them. Lipid formulations of a glutathione analog and methods of manufacturing them. Their use to stimulate hematopoiesis, protect hematopoietic cells from damage caused by radiation or chemotherapy, or potentiate the stimulatory action of one or a combination of cytokines on colony formation by hematopoietic progenitor cells, protect a subject from a destructive effect of a chemotherapeutic agent or irradiation, or to potentiate the effect of a chemotherapeutic agent.
Patent KR-20010110452-A (KR)
IPC: G01N27/68
Filed: 2000-02-18
Abstract: 분석 기구에 있어서, 상기 기구는 다-차원(multi-dimensional) 검출기 시스템으로 설비된 유도 결합 플라즈마 재료 질량 분광계(Inductively Coupled Plasma Source Mass Spectrometer)를 제공하고, 여기서 질량 분광계에 의해 전도 (transmit)된 이온들은 높은 선택도로 검출되는 것을 특징으로 하는 분석기.
Patent KR-20010108276-A (KR)
Filed: 2000-02-25
Abstract: 모듈형 액츄에이터 조립체는, 바람직하게는 구조 폴리머에 의해 전극이 형성된 시트에 부착되어 카드를 형성하는 전기 능동형 물질로 된 하나 혹은 그 이상의 판 혹은 소자를 포함한다. 카드는 밀봉되고, 그리고 고체 혹은 유체의 함유물과 직접 접촉하는, 날개, 요동장치, 교반기, 지렛대, 추진기 혹은 초음파 처리기와 같은 실제적 장치를 그 자체가 구성하거나, 또는 단단한 접착제에 의해 접착되어 고체 작업물, 장치, 기재 기계 혹은 샘플과 면-대-면의 기계적 연결을 이룰 수 있다. 구조 폴리머는 얇은 판이 그것의 파괴점까지 변형하지 않도록 하는 굽힘 강성과, 전단력이 판으로부터 작업물로 효과적으로 연결되게 하는 기계적 강성을 제공한다. 다른 실시예에 있어서, 카드는 스위칭, 동력 공급 혹은 신호 처리용 능동 회로 소자 및/또는 필터링, 정합, 혹은 댐핑 신호용 수동 회로 소자를 포함할 수 있고, 그 결과 회로 외측으로의 연결이 요구되지 않거나 거의 요구되지 않는다. 액츄에이터 조립체는, 작업물에 대한 무시할만한 질량 하중을 유도하는, 균일한 기계적인 작동 특성을 갖는 다양한 액츄에이터를 제공하도록 제공된다. 카드 그 자체는, 유도된 스트레인이 카드의 위치를 변화시키는 스트레인 전달 작동보다는 오히려 독립적인 기계적 액츄에이터로서 배열될 수 있다. 핀 연결되거나 외팔보로 된 카드의 다양한 배열은 추진기, 굽힘기, 혹은 다른 동적 액츄에이터로서 작용할 수 있고, 동력 주름상자와 같은 구조체는 하나 혹은 그 이상의 적절히 패턴화된 카드에 의해 직접 형성될 수 있다.
Patent KR-20020009575-A (KR)
Inventor: CHANG EUNG SOON
IPC: H01Q1/24
Filed: 2000-09-25
Abstract: PURPOSE: An antenna for a mobile communication terminal is provided to enhance communication quality by extending the antenna length even when the mobile communication device is slimmed and an optimized length of the antenna is not secured. CONSTITUTION: Provided is an antenna for a mobile communication terminal in which part of an antenna rod is slidably mounted into an assist antenna rod such that the antenna may be selectively extended in one or two stages. A connecting portion between the antenna rod and the assist antenna rod is rolled so that the antenna rod is prevented from being easily escaped from the assist antenna rod when the antenna is extended in two-stage.
Patent KR-20010113743-A (KR)
Title: Isobutene polymerisation process
IPC: C08F2/38
Filed: 2000-03-09
Abstract: The present application relates to a process for the continuous polymerization of isobutene while maintaining at a constant desired value a property P (viscosity or average molecular mass) of the polymer produced. The polymerization is conducted in a reactor comprising a boiling liquid reaction phase which contains the monomer and the polymer being formed, in equilibrium with a gas phase on top of the said liquid phase, by continuous introduction into the reactor of a catalyst and of a C4 hydrocarbon feed mixture comprising the monomer, and by continuous withdrawal from the reactor of the liquid reaction phase, which is subsequently subjected continuously to at least one purification step which is intended to isolate the polyisobutene produced. The process comprises the determination of a target value V of the partial pressure piC4 of the isobutene in the gas phase of the reactor corresponding to the property P, by virtue of an empirical relationship established beforehand between the property P of the polyisobutene produced and piC4. During the polymerization, piC4 is measured and held constant at around the target value V by acting on the flow rate Qc of the catalyst introduced into the reactor and/or on the flow rate Qh of the C4 hydrocarbon feed mixture.
Patent KR-20010114239-A (KR)
IPC: B01D65/00
Filed: 2000-04-03
Abstract: 본 발명은 반도체 제조 공정, 프린터, 액정 봉입 공정, 약액 제조 공정 등에 있어서, 약액 탈기에 사용되는 중공사막 모듈 및 그의 포팅재, 이 중공사막 모듈을 이용한 약액 탈기 방법에 관한 것이다.  본 발명의 중공사막 모듈 (1)은 포팅재 (2)가 시험편을 약액에 실온에서 6개월간 침지시킨 후의 이 시험편의 단위 표면적 당 질량 변화가 -20 내지 +20 mg/cm 2 의 범위 내인 에폭시 수지 경화물이고, 하우징재 (4)가 시험편을 약액에 실온에서 6개월간 침지시킨 후의 이 시험편의 질량 변화가 -20 내지 +20 mg/cm 2 의 범위 내에서 금속의 총함유량이 300 ppm 이하인 폴리올레핀인 것을 특징으로 하며, 모듈 누설을 발생하지 않고 장기간 약액 처리에 사용할 수 있는 것이다.
Patent KR-20020005668-A (KR)
Title: Pharmaceutical compounds
IPC: A61P39/06
Filed: 2000-04-11
Abstract: Compounds or their salts having general formulas (I) and (II) wherein: s=is an integer equal to 1 or 2, preferably s=2; b0=0 or 1; A is the radical of a drug and is such as to meet the pharmacological tests reported in the description, C and C<SUB>1 </SUB>are two bivalent radicals. The precursors of the radicals B and B<SUB>1 </SUB>are such as to meet the pharmacological test reported in the description.
Patent KR-20020008390-A (KR)
Title: Microencapsulated solid pesticides
IPC: A01N25/28
Filed: 2000-04-13
Abstract: A microcapsule characterized by comprising a solid pesticide as a core material coated with a wall material which is a resin formed by polycondensation of a sparingly water-soluble melamine-formaldehyde resin type prepolymer (said sparingly water-soluble melamine-formaldehyde resin type prepolymer dissolves 2000 g or less of water therein per 100 g of solid component of the prepolymer at ±25° C.) in the presence of a dispersant which is a condensation product of naphthalenesulfonic acid and/or alkylnaphthalenesulfonic acid and formaldehyde or a salt thereof, a method for producing said microcapsule, and a method for applying said microcapsule are disclosed.
Patent KR-20020000640-A (KR)
Title: Thread-forming polyesters and copolyesters and method for producing the same
IPC: C08G63/20
Filed: 2000-05-06
Abstract: The invention relates to thread-forming polyesters and copolyesters containing chemical modifying agents in the form of condensed-in chain branching agents and physical modifying agents in the form of polymeric additives that essentially form no chemical bond with the thread-forming polyesters and copolyesters. The ratio of chemical modifying agents to physical modifying agents by percentage by weight in relation to the thread-forming polyesters and copolyesters is between 0.001 and 0.5. The inventive polyesters and copolyesters are excellently suited to high-speed spinning of textile and industrial yarns with winding speeds of 2500 to 10 000 m/min and to the subsequent processes, e.g. stretching and texturing.
Patent KR-20020060083-A (KR)
Inventor: GOMITA TOSHIMITSU
IPC: D06F37/00
Filed: 2002-01-08
Abstract: PURPOSE: To reduce the occurrence of such a trouble that an outer tub hits an outer frame or the like even when the deviation of clothing occurs during a spin-drying process in a washing machine and to reduce the vibration of the outer frame and the noise caused by it. CONSTITUTION: This vibration control device is provided with a support rod 2 supporting a washing/spin-drying tub and the outer tub from above a main body, a sliding tube 12 into which the support rod penetrates, a slider 13 disposed at the lower end of the support rod and vertically vibrated in contact with the inner periphery of the sliding tube via a vibration control spring 11, a vibration control tube 14 kept in contact with the outer periphery of the vibration control spring, and a ring spring 15 added on the lower section inner periphery of the slider. The slider is provided with air holes 16a and 16b penetrating into the sliding tube. A damping ratio is increased to increase frictional damping until the revolving speed of the washing/spin-drying tub passes a resonance point, and the damping ratio is reduced to reduce air damping after the revolving speed passes the resonance point. As the ratio of damping elements at resonance, the sum of both frictional and viscous damping ratios is set to 8 or above against the air damping ratio of less than 2.
Patent KR-20020023384-A (KR)
Title: Glasses frame with an auxiliary frame
Inventor: SON TAE SON
IPC: G02C9/00
Filed: 2002-01-22
Abstract: PURPOSE: An eyeglass frame having a function of auxiliary eyeglasses is provided to install easily the auxiliary eyeglasses such as sunglasses, convex glasses, and concave glasses by installing an auxiliary eyeglass frame to the existing eyeglass frame. CONSTITUTION: A spectacle lens fixing portion of an existing eyeglass frame(4,4') is formed with projecting magnets(1,1'). An auxiliary eyeglass frame(5,5') is used for fixing an auxiliary eyeglasses such as sunglasses, convex glasses, and concave glasses. One end portion of a fixing portion of the auxiliary eyeglass frame(5,5') is formed with concave magnets(2,2') for covering the projecting magnets(1,1') and grooves(3,3') for covering the existing spectacles rim(4,4'). The other end portion of the fixing portion of the auxiliary eyeglass frame(5,5') is formed with rotary rings(6,6') combined with bolts(8,8') and nuts(7,7').
Patent KR-20030066962-A (KR)
Inventor: CHO SEONG JAE
IPC: H01M2/12
Filed: 2002-02-06
Abstract: PURPOSE: A lithium secondary battery which can emit the gas under high pressure generated in the battery is provided to increase the stability of the battery. CONSTITUTION: The lithium secondary battery comprises: an electrode assembly(12) composed of a cathode plate, an anode plate and a separator inserted therebetween; a case(11) which encloses the electrode assembly(12) and has a safety valve(15) at the bottom thereof; a cap assembly(20) mounted at the upper opening of the case(11) which seals the inside of the case(11); and a lower taping member(32) which surrounds the lower part of the electrode assembly(12) and has a groove(33) conformable to the safety valve(15) so that the electrode assembly(12) can be inserted in the case(11) with ease.
Patent KR-20020066978-A (KR)
Inventor: FUMIKURA TATSUKI
IPC: G09F9/00
Filed: 2002-02-07
Abstract: PURPOSE: To prevent luminance of respective light sources from lowering due to temperature elevation of the respective light sources, caused by radiant heat from the other light sources in a liquid crystal display which employs a side light type backlight unit with a plurality of the light sources arranged in the inside. CONSTITUTION: The liquid crystal display is provided with a liquid crystal display element, having a pair of substrates and a liquid crystal sandwiched between a pair of the substrates and the backlight unit arranged on a side of the liquid crystal display element opposite to the display screen. The backlight unit is provided with a light transmission body, a plurality of the light sources arranged in a direction perpendicularly intersecting the display screen of the liquid crystal display element, at least on one side of the light transmission body and making irradiating light irradiate the liquid crystal display element, reflection members covering the respective light sources and having shielding means to be arranged between the respective light sources, and a housing member to accommodate the light transmission body, a plurality of the light sources and the reflecting members.
Patent KR-20030068725-A (KR)
Title: Method for manufacturing liquid crystal display device
Inventor: LEE SANG SEOK
IPC: G02F1/13
Filed: 2002-02-16
Abstract: PURPOSE: A method for manufacturing a liquid crystal display is provided to reduce time required for a process before joining two substrates, efficiently operate the production line, and prevent a sealant from being contaminated by particles. CONSTITUTION: A second glass substrate on which a sealant is applied is cleaned to remove particles(31S). The second substrate is fixed on an upper stage of a vacuum joining chamber(32S). A first substrate on which liquid crystal is dropped is fixed on a lower stage of the vacuum joining chamber(33S). A glass receiver is placed under the second glass substrate(34S). The vacuum joining chamber is vacuumed(35S). The upper and lower stages fix the first and second glass substrates by an ESC(Electric Static Charge)(36S). The glass receiver is returned to the original position(37S). The upper stage is descended to press the first and second glass substrates to join the first and second glass substrates together(38S). Clean dry air is supplied to the vacuum joining chamber to vent the vacuum joining chamber(39S). The pressed glass substrates are unloaded(40S).
Patent KR-20030069455-A (KR)
Title: Sliced bread tray assembly for microwave oven having toaster
Inventor: BAEK YUN GEON
IPC: H05B6/80
Filed: 2002-02-20
Abstract: PURPOSE: A sliced bread tray assembly is provided to achieve improved use convenience by allowing the sliced bread to be heated in a uniform manner. CONSTITUTION: A combined microwave oven and toaster comprises a toaster door mounted on a toaster panel forming a front surface of a toaster and which opens/shuts the toaster; a tray assembly including a tray on which sliced bread is disposed, a tray support(70) disposed beneath the tray, and a coupling member for coupling the tray to the tray support; a heater arranged at both sides of the sliced bread disposed on the tray assembly, and which generates a heat for heating the sliced bread; and a link unit for transmitting the drive force generated from the opening/shutting operation of the toaster door to the tray assembly.
Patent KR-20030070364-A (KR)
Title: A repairing and a reballing method of ball grid array packages
Inventor: KIM GYEONG DU
IPC: H01L21/60
Filed: 2002-02-25
Abstract: PURPOSE: A method for fabricating repairing and reballing a ball grid array(BGA) package is provided to improve the quality of a package module by effectively performing a repairing process on the BGA package, and to reduce fabricating cost by recycling a used BGA package through a reballing method. CONSTITUTION: The package module is baked(41). A defective package is separated from the board(42). The residual solder ball on the board is eliminated through a dressing process and a cleaning process(43). A good quality package is temporarily attached to the cleaned board by using the heat applied form a vacuum nozzle(44). The good quality package is permanently attached to the board through a reflow process(45).
Patent KR-20030071028-A (KR)
Title: Defect detecting circuit and method of optical disc
Inventor: JUNG BYEONG GUK
IPC: G11B7/004
Filed: 2002-02-27
Abstract: PURPOSE: A circuit and method for detecting defects in an optical disk are provided to detect defects included in an RF signal with a simple construction to improve reliability in the operation of an optical disk player. CONSTITUTION: A circuit for detecting defects in an optical disk includes an upper envelope detector(10), a lower envelope detector(20), a differential amplifier(30), the first and second comparators(40,50), and an OR gate(60). The upper envelope detector detects upper envelope of an RF signal detected from the optical disk by an optical pick-up. The lower envelope detector detects lower envelope of the RF signal. The differential amplifier generates a difference voltage of the output signals of the upper and lower envelope detectors. The first comparator compares the difference voltage with the first reference voltage to generate an interruption defect detection signal. The second comparator compares the difference voltage with the second reference voltage to generate a defect detection signal. The OR gate ORs the output signals of the first and second comparators to generate a final defect detection signal.