WO2014121878A1 - Carte de circuit imprimé - Google Patents

Carte de circuit imprimé Download PDF

Info

Publication number
WO2014121878A1
WO2014121878A1 PCT/EP2013/077489 EP2013077489W WO2014121878A1 WO 2014121878 A1 WO2014121878 A1 WO 2014121878A1 EP 2013077489 W EP2013077489 W EP 2013077489W WO 2014121878 A1 WO2014121878 A1 WO 2014121878A1
Authority
WO
WIPO (PCT)
Prior art keywords
circuit board
region
heat dissipation
heat
electrode region
Prior art date
Application number
PCT/EP2013/077489
Other languages
English (en)
Inventor
Jianghui YANG
Peng Chen
Yusheng MING
Haiquan CHEN
Original Assignee
Osram Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Osram Gmbh filed Critical Osram Gmbh
Publication of WO2014121878A1 publication Critical patent/WO2014121878A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/0201—Thermal arrangements, e.g. for cooling, heating or preventing overheating
    • H05K1/0203—Cooling of mounted components
    • H05K1/0209—External configuration of printed circuit board adapted for heat dissipation, e.g. lay-out of conductors, coatings
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/0201—Thermal arrangements, e.g. for cooling, heating or preventing overheating
    • H05K1/0203—Cooling of mounted components
    • H05K1/0204—Cooling of mounted components using means for thermal conduction connection in the thickness direction of the substrate
    • H05K1/0206—Cooling of mounted components using means for thermal conduction connection in the thickness direction of the substrate by printed thermal vias
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/09—Shape and layout
    • H05K2201/09209—Shape and layout details of conductors
    • H05K2201/09654—Shape and layout details of conductors covering at least two types of conductors provided for in H05K2201/09218 - H05K2201/095
    • H05K2201/09663—Divided layout, i.e. conductors divided in two or more parts
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/09—Shape and layout
    • H05K2201/09209—Shape and layout details of conductors
    • H05K2201/09654—Shape and layout details of conductors covering at least two types of conductors provided for in H05K2201/09218 - H05K2201/095
    • H05K2201/09781—Dummy conductors, i.e. not used for normal transport of current; Dummy electrodes of components
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/10—Details of components or other objects attached to or integrated in a printed circuit board
    • H05K2201/10007—Types of components
    • H05K2201/10106—Light emitting diode [LED]
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/10—Details of components or other objects attached to or integrated in a printed circuit board
    • H05K2201/10007—Types of components
    • H05K2201/10204—Dummy component, dummy PCB or template, e.g. for monitoring, controlling of processes, comparing, scanning

Definitions

  • the present invention relates to a circuit board for an elec ⁇ tronic device, in particular a circuit board for an illumi ⁇ nating device.
  • an illuminating de ⁇ vice with an LED as light source has a driver circuit that is particularly configured for LED devices, such an LED driver circuit can be provided on a printed circuit board (PCB tech ⁇ nology) , and such a conventional circuit board can provide stable electric energy for the LED driver circuit, in par ⁇ ticular for an LED chip controlled by the same.
  • PCB tech ⁇ nology printed circuit board
  • heat dissipation performance of circuit boards is one of principal factors that influence the performances of elec ⁇ tronic devices, e.g.
  • FIG. 1 shows a schematic top view of an embodiment of a circuit board 10 according to the prior art.
  • the circuit board 10 has a conducting layer 2 for emplacing an electronic device, said conducting layer 2 includes an electrode region 21 which is divided into an anode electrode region and a cathode electrode region, the two electrode regions can be respectively in electrical connec ⁇ tion with the positive pin and negative pin of the electronic device, for example of an LED chip.
  • a plu ⁇ rality of through holes 23 is particularly opened in a pe- ripheral region of the conducting layer 2, and said through holes can be distributed in an array.
  • Figure 2 shows a sectional view of the circuit board as shown in Figure 1.
  • an LED chip is carried on one side (top surface in the figure) of the circuit board 10, and a conducting layer 2 is arranged between the substrate 1 of the circuit board 10 and the LED chip.
  • the four through holes 23 shown in Figure 1 are respectively symmetrically positioned at both sides of the LED chip, and these through holes 23 penetrate the whole circuit board 10, in other words, successively penetrate the conducting layer 2 and the substrate 1.
  • it is dis ⁇ advantageous that the through holes 23 opened on the circuit board 10 would form unnecessary electrical connection paths, which would decrease electrical insulation performance of said circuit board.
  • said solution can obvi ⁇ ously lower the thermal resistance of the circuit board and increase the thermal conductivity, it simultaneously de- creases the electrical insulation strength of the circuit board, which may bring adverse influences for an electronic device having such a circuit board mounted, for example, the stability and reliability of the electronic device during op ⁇ eration are decreased. And said disadvantage greatly limits the application range of the circuit board in the prior art.
  • the present invention provides a novel circuit board for an elec ⁇ tronic device.
  • the circuit board according to the present invention has the characteristic of low thermal resistance, so as to assure a good heat dissipation effect of the circuit board during a working state.
  • such a circuit board can simultaneously have high insulation strength, so as to advantageously satisfy the requirements of a user on its insulation performance.
  • An object of the present invention is achieved through a cir ⁇ cuit board for an electronic device, viz. said circuit board comprises an insulating substrate and a conducting layer arranged at one side of the substrate, characterized in that the conducting layer includes an electrode region and at least one heat dissipation region that is separated from the electrode region, wherein at least one through hole is opened in the heat dissipation region, and at least one electrically isolated heat-conductive structure is provided between the electrode region and the at least one heat dissipation re ⁇ gion.
  • the present invention provides a design for improving the circuit board in the prior art, which divides the elec- trode region and the heat dissipation region of the conduct ⁇ ing layer configured as top surface of the circuit board, that are integrally provided according to the prior art, into at least two regions separated from each other, so as to form an electrode region and at least one heat dissipation region that is electrically isolated from the electrode region.
  • at least one, probably a plurality of through holes is preferably opened in said heat dissipation region according to actual demands, and the or these through holes can act as typical heat dissipation structure in a circuit board to dissipate heat of the circuit board.
  • At least one electrically iso ⁇ lated heat-conductive structure is particularly preferably provided between the electrode region and the at least one heat dissipation region, in order that the circuit board ac ⁇ cording to the present invention has a good heat dissipation effect, and simultaneously a good insulation effect.
  • Said heat-conductive structure transfers the heat of the electrode region to the heat dissipation region in a form of "heat- conductive bridge", while the electric charges of the elec ⁇ trode region would not be transferred to the heat dissipation region together with the heat.
  • the circuit board according to the present invention provides the possibility of simultane ⁇ ously assuring good heat dissipation performance and good in ⁇ sulation performance.
  • the heat-conductive structure is a heat conductor, with both edges respectively overlapped the electrode region and the attributive heat dissipation region.
  • the heat-conductive structure configured in such a manner due to its electrical isolation performance, can provide an effec ⁇ tive and simple way for heat transfer without detracting the insulation performance, while the electrode region and the heat dissipation region are electrically isolated.
  • the heat conductor is a ceramic plate. Ceramic has fine heat-conductive performance, and good insu ⁇ lation performance. In a situation that the heat conductor is made of a ceramic material in accordance with dimensions of international standard, not only the limited space on the circuit board can be effectively saved, so that the circuit board obtains an advantageous structural layout; the heat conductor can also be enabled to improve the heat dissipation effect of said circuit board without detracting the insula- tion performance of said circuit board. In addition, the heat conductor of such a specification may also be extensively applied to other illuminating devices having enough space, to improve their heat dissipation effect.
  • the through hole penetrates the sub- strate.
  • An effective and direct heat-conductive path can be formed by opening a through hole on the conducting layer of said circuit board and enabling the same to penetrate the substrate of said circuit board.
  • Such a heat-conductive path improves the heat dissipation effect of said circuit board.
  • the electrical insulation effect between elec ⁇ trical assemblies mounted on the electrode region and the through hole is achieved.
  • the cir- cuit board per se has good insulation strength, so as to en ⁇ sure that the electronic device using said circuit board has a stable working environment.
  • the heat conductor is fixed on the con ⁇ ducting layer by SM .
  • Said technology can mount said heat conductor on the conducting layer and firmly fix it on said layer, without affecting the original layout of the circuit board as much as possible. Moreover, the cost and time for manufacturing the whole circuit board can be decreased through said mainstream mounting technique.
  • a first solder pad is provided at the side of the heat conductor facing to the electrode region, and a second solder pad is provided at the side of the heat conductor facing to the heat dissipation region.
  • Said heat conductor is connected with and fixed on the conducting layer of the circuit board through said first and second solder pads, and acts as an effective way of transferring heat.
  • said design further allows an enough insulation distance to exist between the electrode region and the heat dissipation region.
  • the ceramic plate is made from any of AI 2 O 3 or A1N, or from their mixtures.
  • Aluminum oxide and aluminum nitride have relatively high thermal conductivity and relatively good insulation strength, the thermal conduc ⁇ tivity of a heat-conducting plate could therefore be greatly improved, if a ceramic plate made from the two kinds of sub ⁇ stances mentioned above or their mixture is used as heat- conducting plate.
  • Such a ceramic plate can transfer heat of the electrode region to the heat dissipation region as much as possible to lower the temperature of a high temperature region (viz. the electrode region) of the circuit board and to achieve a good heat dissipation effect.
  • the electronic device is fixed on the electrode region.
  • the electrode region on said circuit board ⁇
  • the electrode region includes an anode region and a cathode region that are separated from each other, and the positive and negative pins of the electronic devices are respectively in electrical connection with the anode region and the cathode region.
  • the conducting layer of said circuit board is divided into the anode region and cathode region separated from each other, a way for direct electrical connection can be provided for the electronic de ⁇ vice, and in this case, it is convenient to electrically con ⁇ nect the positive and negative pins of the electronic device respectively with the corresponding anode region and cathode region on the circuit board. And such an electrical connec ⁇ tion is direct, simple and effective.
  • the conducting layer includes two heat dissipation regions that are symmetrically located at both sides of the electrode region.
  • the object of improving the heat dissipation effect of said circuit board can be achieved through the arrangement of a plurality of heat dissipation regions.
  • the heat dissipation regions are ar ⁇ ranged at both sides of said electrode region, an uniform and overall heat dissipation path can be formed on the circuit board, so as to obtain the effect of an overall heat dissipa- tion on said circuit board to assure a good working environ ⁇ ment of said circuit board.
  • the substrate is made of FR4 or CEM-3 base material.
  • Said base material has good flame-retardant effect, and can be adequately adaptive to certain severe ap ⁇ plication environments to assure the service life of said circuit board.
  • said FR4 or CEM-3 base material is a relative common material, which can not only be widely ap ⁇ plied to enhance heat dissipation effect of circuit boards, but also effectively save manufacturing costs of circuit boards .
  • Figure 1 shows a schematic top view of an embodiment of a circuit board according to the prior art
  • Figure 2 shows a sectional view of the circuit board as shown in Figure 1 ;
  • Figure 3 shows a sectional view of an embodiment of a circuit board according to the present invention
  • Figure 4 shows a schematic top view of an embodiment of the circuit board according to the present invention.
  • the circuit board 10 for an electronic device 100 comprises an insulating substrate 1 and a conducting layer 2 arranged at one side of the sub ⁇ strate 1, characterized in that the conducting layer 2 in ⁇ cludes an electrode region 21 and at least one heat dissipa- tion region 22 that is separated from the electrode region 21 , wherein at least one through hole 23 is opened in the heat dissipation region 22, and at least one electrically isolated heat-conductive structure is provided between the electrode region 21 and the at least one heat dissipation re- gion 22.
  • FIG. 3 shows a sectional view of an embodiment of the cir ⁇ cuit board 10 according to the present invention.
  • said circuit board 10 comprises a substrate 1 and a conducting layer 2, which further includes an electrode region 21 and at least one heat dissipation region 22 (there are two heat dissipation regions in the present embodiment) , wherein said electrode region 21 is preferably positioned be ⁇ tween the two heat dissipation regions 22, and maintains a certain distance with respect to the two heat dissipation re- gions 22.
  • At least one through hole 23 is opened in the heat dissipation region 22, and at least one heat-conductive structure is arranged between said electrode region 21 and the heat dissipation region 22, while Figure 3 only schemati- cally shows two through holes 23 and two heat-conductive structures configured as heat conductors 3.
  • Said heat con ⁇ ductor 3 has the function of electrically isolating the elec ⁇ trode region 21 and the heat dissipation region 22 from each other.
  • the two heat conductors 3 are symmetrically overlapped between the electrode region 21 and the attribu ⁇ tive heat dissipation region 22, respectively.
  • said heat conductor 3 can be a ceramic plate made from any one of aluminum oxide (AI 2 O3) or aluminum nitride (A1N) or any one of their mixtures.
  • a ceramic plate with said compo ⁇ sition has a relatively high thermal conductivity and rela ⁇ tively good insulation strength.
  • FIG. 3 further shows that the through holes 23 penetrating the circuit board 10 are opened in the respective heat dissi ⁇ pation regions 22, and said through hole 23 penetrates the conducting layer 2 and the substrate 1 under the conducting layer 2, successively.
  • the heat conductors 3 are respectively in fixed connection with the electrode region 21 and the heat dissipation region 22 at both sides in the horizontal direction as shown in the figure by means of a first solder pad 4 and a second solder pad 5.
  • the first solder pad 4 is specifically arranged at the side facing to the elec- trode region 21, and the second solder pad 5 is specifically provided at the side facing to the heat dissipation region 22.
  • Figure 4 shows a schematic top view of an example of the cir ⁇ cuit board 10 according to the present invention. Said fig ⁇ ure only schematically shows the circuit board.
  • the substrate of said circuit board 10 utilizes FR4 or CEM-3 base material, and a heat conductor 3 performing in ⁇ sulated heat conductance in a form of "heat-conductive bridge" is arranged on the conducting layer 2 of said circuit board 10. Specifically, both edges of said heat conductor 3 are respectively fixed on the electrode region 21 and the heat dissipation region 22 of the conducting layer 2 through SMT (SMT) .
  • SMT SMT
  • Figure 4 further shows that two heat dissipation regions 22 are provided on said conducting layer 2, which are symmetrically positioned at both sides of the electrode layer 21.
  • the object of improving the heat dissipation effect of the circuit board 10 according to the present invention can be achieved by arranging a plurality of heat dissipation regions 22.
  • heat produced locally on said circuit board can be uniformly and overall trans ⁇ ferred to other regions having relative lower temperatures, so as to realize an overall heat dissipation effect of said circuit board and assure a good working environment of said circuit board.
  • an electronic device 100 can be mounted on the electrode region 21 of said circuit board 10, a simple and easy electrical connection can therefore be realized.
  • Said electrode region 21 further includes an anode region 211 and a cathode region 212, which are separated from each other and with which the positive and negative pins of the electronic device 100 are respectively in electrical connection.
  • anode region 211 and a cathode region 212 which are separated from each other and with which the positive and negative pins of the electronic device 100 are respectively in electrical connection.

Landscapes

  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Structure Of Printed Boards (AREA)

Abstract

La présente invention se rapporte à une carte de circuit imprimé (10) pour un dispositif électronique (100), la carte de circuit imprimé (10) comprenant un substrat isolant (1) et une couche conductrice (2) agencée sur un côté du substrat (1), ladite carte de circuit imprimé étant caractérisée en ce que la couche conductrice (2) comprend une région d'électrode (21) et au moins une région de dissipation de chaleur (22) qui est séparée de la région d'électrode (21), au moins un trou traversant (23) étant ouvert dans la région de dissipation de chaleur (22) et au moins une structure thermoconductrice électriquement isolée étant agencée entre la région d'électrode (21) et la ou les régions de dissipation de chaleur (22).
PCT/EP2013/077489 2013-02-05 2013-12-19 Carte de circuit imprimé WO2014121878A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201310045973.2 2013-02-05
CN201310045973.2A CN103974598A (zh) 2013-02-05 2013-02-05 电路板

Publications (1)

Publication Number Publication Date
WO2014121878A1 true WO2014121878A1 (fr) 2014-08-14

Family

ID=49880780

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2013/077489 WO2014121878A1 (fr) 2013-02-05 2013-12-19 Carte de circuit imprimé

Country Status (2)

Country Link
CN (1) CN103974598A (fr)
WO (1) WO2014121878A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106488686A (zh) * 2015-08-31 2017-03-08 上海伯乐电子有限公司 照明器件、电气组件、柔性电路及热传递方法
CN111447728A (zh) * 2020-04-17 2020-07-24 歌尔微电子有限公司 柔性电路板及电子设备

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105101613A (zh) * 2014-11-19 2015-11-25 芜湖蓝宙电子科技有限公司 提高表面贴装器件印制板导热能力的方法
CN105792597A (zh) * 2014-12-23 2016-07-20 中兴通讯股份有限公司 一种散热装置、电路板及其设计方法
JP2018524534A (ja) * 2015-05-04 2018-08-30 ジョンソン コントロールズ テクノロジー カンパニーＪｏｈｎｓｏｎ Ｃｏｎｔｒｏｌｓ Ｔｅｃｈｎｏｌｏｇｙ Ｃｏｍｐａｎｙ 制御システムハブおよび遠隔センサを備えた多機能ホーム制御システム
US10123460B2 (en) * 2015-11-13 2018-11-06 Covidien LLP System and method for thermal management of electronic devices
WO2017128212A1 (fr) * 2016-01-28 2017-08-03 深圳市嘉合劲威电子科技有限公司 Carte de circuits imprimés et mémoire l'utilisant

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2259408A (en) * 1991-09-07 1993-03-10 Motorola Israel Ltd A heat dissipation device
US20040226696A1 (en) * 2003-02-28 2004-11-18 Hong Huang Surface mount resistors as heat transfer augmentation devices
US20070242462A1 (en) * 2006-04-16 2007-10-18 Peter Van Laanen Thermal management of led-based lighting systems
EP2276329A1 (fr) * 2009-07-16 2011-01-19 ABB Research Ltd. Carte de circuit électronique dotée d'un condensateur thermique

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2259408A (en) * 1991-09-07 1993-03-10 Motorola Israel Ltd A heat dissipation device
US20040226696A1 (en) * 2003-02-28 2004-11-18 Hong Huang Surface mount resistors as heat transfer augmentation devices
US20070242462A1 (en) * 2006-04-16 2007-10-18 Peter Van Laanen Thermal management of led-based lighting systems
EP2276329A1 (fr) * 2009-07-16 2011-01-19 ABB Research Ltd. Carte de circuit électronique dotée d'un condensateur thermique

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106488686A (zh) * 2015-08-31 2017-03-08 上海伯乐电子有限公司 照明器件、电气组件、柔性电路及热传递方法
CN111447728A (zh) * 2020-04-17 2020-07-24 歌尔微电子有限公司 柔性电路板及电子设备

Also Published As

Publication number Publication date
CN103974598A (zh) 2014-08-06

Similar Documents

Publication Publication Date Title
WO2014121878A1 (fr) Carte de circuit imprimé
CN100442552C (zh) 带有散热板的发光二极管装置
US8823145B2 (en) Multilayer board and light-emitting module having the same
US7808788B2 (en) Multi-layer electrically isolated thermal conduction structure for a circuit board assembly
CN100517025C (zh) 装备有发光二极管的背光装置
KR101049698B1 (ko) Ｌｅｄ 어레이 모듈 및 이의 제조방법
US20110180819A1 (en) Light-emitting arrangement
JP2005158957A (ja) 発光装置
US20110290537A1 (en) Multilayer circuit substrate
CN205491427U (zh) 带有陶瓷散热器的高频印刷电路板及led光源模组
CN108990254B (zh) 内建纵向散热陶瓷块印刷电路板及具该电路板的电路组件
JP2004119515A (ja) 高い放熱性を有する発光ダイオード表示モジュール及びその基板
RU2423803C2 (ru) Монтажная панель для электронного компонента
KR20050073571A (ko) 집적 회로 장치, 전자 회로 지지 기판 및 집적 회로와 히트싱크의 열적 접속 방법
KR100775449B1 (ko) 방열층 구조를 가진 회로 기판
KR20120001460A (ko) 발광모듈 및 그를 이용한 헤드 램프 모듈
ES2943137T3 (es) Circuito de alta corriente
KR101115403B1 (ko) 발광 장치
CN205248305U (zh) 一种两面出光的led灯
KR101064793B1 (ko) 방열엘이디보드
KR100660126B1 (ko) 방열판 구조를 가진 회로 기판
KR20110129614A (ko) 고효율의 열방출이 가능한 전기전자 장치 및 ｌｅｄ 발광 장치
CN110996501A (zh) 具有贯穿式导电及散热部件的电路板和功率模组
CN208572543U (zh) 内嵌散热器的多层电路板
JP2012160528A (ja) 半導体パッケージ

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 13811952

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 13811952

Country of ref document: EP

Kind code of ref document: A1