SG11201600591VA - Bonding electronic components to patterned nanowire transparent conductors - Google Patents

Bonding electronic components to patterned nanowire transparent conductors

Info

Publication number
SG11201600591VA
SG11201600591VA SG11201600591VA SG11201600591VA SG11201600591VA SG 11201600591V A SG11201600591V A SG 11201600591VA SG 11201600591V A SG11201600591V A SG 11201600591VA SG 11201600591V A SG11201600591V A SG 11201600591VA SG 11201600591V A SG11201600591V A SG 11201600591VA
Authority
SG
Singapore
Prior art keywords
electronic components
transparent conductors
bonding electronic
nanowire transparent
patterned nanowire
Prior art date
Application number
SG11201600591VA
Other languages
English (en)
Inventor
Matthew S Stay
Mikhail L Pekurovsky
Shawn C Dodds
Ann M Gilman
Daniel J Theis
Original Assignee
3M Innovative Properties Co
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 3M Innovative Properties Co filed Critical 3M Innovative Properties Co
Publication of SG11201600591VA publication Critical patent/SG11201600591VA/en

Links

Classifications

    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • 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
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/22—Secondary treatment of printed circuits
    • H05K3/28—Applying non-metallic protective coatings
    • H05K3/284—Applying non-metallic protective coatings for encapsulating mounted components
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/0412—Digitisers structurally integrated in a display
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/047—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means using sets of wires, e.g. crossed wires
    • 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
    • H05K1/0277—Bendability or stretchability details
    • H05K1/028—Bending or folding regions of flexible printed circuits
    • 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
    • H05K1/0296—Conductive pattern lay-out details not covered by sub groups H05K1/02 - H05K1/0295
    • 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
    • H05K1/09—Use of materials for the conductive, e.g. metallic pattern
    • 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
    • H05K1/09—Use of materials for the conductive, e.g. metallic pattern
    • H05K1/092—Dispersed materials, e.g. conductive pastes or inks
    • H05K1/097—Inks comprising nanoparticles and specially adapted for being sintered at low temperature
    • 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
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/02—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding
    • H05K3/04—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding the conductive material being removed mechanically, e.g. by punching
    • H05K3/046—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding the conductive material being removed mechanically, e.g. by punching by selective transfer or selective detachment of a conductive layer
    • H05K3/048—Apparatus or processes for manufacturing printed circuits in which the conductive material is applied to the surface of the insulating support and is thereafter removed from such areas of the surface which are not intended for current conducting or shielding the conductive material being removed mechanically, e.g. by punching by selective transfer or selective detachment of a conductive layer using a lift-off resist pattern or a release layer pattern
    • 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
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/10—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern
    • H05K3/103—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern by bonding or embedding conductive wires or strips
    • 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
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
    • H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
    • H05K3/321—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by conductive adhesives
    • H05K3/323—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by conductive adhesives by applying an anisotropic conductive adhesive layer over an array of pads
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2203/00—Indexing scheme relating to G06F3/00 - G06F3/048
    • G06F2203/041—Indexing scheme relating to G06F3/041 - G06F3/045
    • G06F2203/04103—Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2203/00—Indexing scheme relating to G06F3/00 - G06F3/048
    • G06F2203/041—Indexing scheme relating to G06F3/041 - G06F3/045
    • G06F2203/04112—Electrode mesh in capacitive digitiser: electrode for touch sensing is formed of a mesh of very fine, normally metallic, interconnected lines that are almost invisible to see. This provides a quite large but transparent electrode surface, without need for ITO or similar transparent conductive material
    • 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
    • H05K1/03—Use of materials for the substrate
    • H05K1/0393—Flexible materials
    • 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
    • H05K2201/02—Fillers; Particles; Fibers; Reinforcement materials
    • H05K2201/0203—Fillers and particles
    • H05K2201/0242—Shape of an individual particle
    • H05K2201/026—Nanotubes or nanowires
    • 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
    • H05K2201/10128—Display
    • 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
    • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
    • H05K2203/01—Tools for processing; Objects used during processing
    • H05K2203/0104—Tools for processing; Objects used during processing for patterning or coating
    • H05K2203/0143—Using a roller; Specific shape thereof; Providing locally adhesive portions thereon
    • 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
    • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
    • H05K2203/14—Related to the order of processing steps
    • H05K2203/1461—Applying or finishing the circuit pattern after another process, e.g. after filling of vias with conductive paste, after making printed resistors
    • H05K2203/1469—Circuit made after mounting or encapsulation of the 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
    • H05K2203/00—Indexing scheme relating to apparatus or processes for manufacturing printed circuits covered by H05K3/00
    • H05K2203/15—Position of the PCB during processing
    • H05K2203/1545—Continuous processing, i.e. involving rolls moving a band-like or solid carrier along a continuous production path

Landscapes

  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Theoretical Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Human Computer Interaction (AREA)
  • Chemical & Material Sciences (AREA)
  • Nanotechnology (AREA)
  • Dispersion Chemistry (AREA)
  • Laminated Bodies (AREA)
  • Non-Insulated Conductors (AREA)
  • Parts Printed On Printed Circuit Boards (AREA)
  • Manufacturing Of Electric Cables (AREA)
SG11201600591VA 2013-07-31 2014-07-18 Bonding electronic components to patterned nanowire transparent conductors SG11201600591VA (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US201361860841P 2013-07-31 2013-07-31
PCT/US2014/047212 WO2015017143A1 (en) 2013-07-31 2014-07-18 Bonding electronic components to patterned nanowire transparent conductors

Publications (1)

Publication Number Publication Date
SG11201600591VA true SG11201600591VA (en) 2016-02-26

Family

ID=52432333

Family Applications (2)

Application Number Title Priority Date Filing Date
SG11201600591VA SG11201600591VA (en) 2013-07-31 2014-07-18 Bonding electronic components to patterned nanowire transparent conductors
SG10201808518RA SG10201808518RA (en) 2013-07-31 2014-07-18 Bonding electronic components to patterned nanowire transparent conductors

Family Applications After (1)

Application Number Title Priority Date Filing Date
SG10201808518RA SG10201808518RA (en) 2013-07-31 2014-07-18 Bonding electronic components to patterned nanowire transparent conductors

Country Status (8)

Country Link
US (1) US9980394B2 (enExample)
EP (1) EP3028126B1 (enExample)
JP (1) JP6426737B2 (enExample)
KR (1) KR102254683B1 (enExample)
CN (1) CN105453001B (enExample)
BR (1) BR112016002093A2 (enExample)
SG (2) SG11201600591VA (enExample)
WO (1) WO2015017143A1 (enExample)

Families Citing this family (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3053012B1 (en) * 2013-09-30 2019-10-23 3M Innovative Properties Company Protective coating for printed conductive pattern on patterned nanowire transparent conductors
US20150108632A1 (en) * 2013-10-23 2015-04-23 Nano And Advanced Materials Institute Limited Thin film with negative temperature coefficient behavior and method of making thereof
JP6592246B2 (ja) * 2015-01-27 2019-10-16 株式会社コムラテック 電子回路基板およびその製造方法
US10298152B2 (en) * 2015-04-20 2019-05-21 Lawrence Livermore National Security, Llc Harvesting mechanical and thermal energy by combining nanowires and phase change materials
JP6498766B2 (ja) * 2015-07-08 2019-04-10 シャープ株式会社 タッチパネル装置
JP6654954B2 (ja) * 2016-03-31 2020-02-26 デクセリアルズ株式会社 異方性導電接続構造体
CN108885515A (zh) * 2016-04-05 2018-11-23 3M创新有限公司 对金属互连结构具有增强粘附性的纳米线接触垫
TWI732892B (zh) * 2016-07-26 2021-07-11 日商松下知識產權經營股份有限公司 透視型電極用積層板、透視型電極素材、組件及透視型電極用積層板之製造方法
WO2019032846A1 (en) * 2017-08-10 2019-02-14 Molex, Llc METHOD AND APPARATUS FOR FORMING AN ELECTRICAL CIRCUIT COMPRISING ALUMINUM AND ONE OR MORE DISSOLVABLE METALS
CA2985254A1 (en) * 2017-11-14 2019-05-14 Vuereal Inc Integration and bonding of micro-devices into system substrate
DE102018106959A1 (de) 2018-03-23 2019-09-26 Osram Opto Semiconductors Gmbh Optoelektronisches bauelement und verfahren zur herstellung eines optoelektronischen bauelements
CN113243045B (zh) * 2019-01-22 2022-11-29 深圳市柔宇科技股份有限公司 柔性显示面板及其制作方法
US11387202B2 (en) 2019-03-01 2022-07-12 Invensas Llc Nanowire bonding interconnect for fine-pitch microelectronics
DE112020001930A5 (de) 2019-04-15 2022-01-05 Wika Alexander Wiegand Se & Co. Kg Sensor zur Erfassung von Druck, Füllstand, Dichte, Temperatur, Masse und/oder Durchfluss
CN113710999A (zh) 2019-04-17 2021-11-26 威卡亚力山大维甘德欧洲两合公司 用于检测压力和/或料位和/或流量和/或密度和/或质量和/或温度的传感器
CN112860130A (zh) * 2019-11-26 2021-05-28 英属维尔京群岛商天材创新材料科技股份有限公司 触控面板及其制作方法
US11261529B2 (en) * 2020-03-31 2022-03-01 Futuretech Capital, Inc. Reduced visibility conductive micro mesh touch sensor
US20250106995A1 (en) * 2023-09-27 2025-03-27 Apple Inc. Compact interface through hinge connector

Family Cites Families (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6037005A (en) * 1998-05-12 2000-03-14 3M Innovative Properties Company Display substrate electrodes with auxiliary metal layers for enhanced conductivity
US6975067B2 (en) 2002-12-19 2005-12-13 3M Innovative Properties Company Organic electroluminescent device and encapsulation method
EP1875787A2 (en) 2005-04-11 2008-01-09 3M Innovative Properties Company Connection method of a flexible printed circuit board with two printed circuit boards, and electric or electronic component with parts connected by the connection
KR101333012B1 (ko) 2005-08-12 2013-12-02 캄브리오스 테크놀로지즈 코포레이션 나노와이어 기반의 투명 도전체
KR101545219B1 (ko) 2006-10-12 2015-08-18 캄브리오스 테크놀로지즈 코포레이션 나노와이어 기반의 투명 도전체 및 그의 응용
KR20100116680A (ko) * 2008-02-26 2010-11-01 캄브리오스 테크놀로지즈 코포레이션 전도성 피처의 잉크젯 침착을 위한 방법 및 조성물
WO2010018733A1 (ja) * 2008-08-11 2010-02-18 コニカミノルタホールディングス株式会社 透明電極、有機エレクトロルミネッセンス素子及び透明電極の製造方法
EP2501770A4 (en) * 2009-11-20 2015-12-09 3M Innovative Properties Co SURFACE MODIFIED LUBRICANTS
KR101219139B1 (ko) * 2009-12-24 2013-01-07 제일모직주식회사 이방 도전성 페이스트, 필름 및 이를 포함하는 회로접속구조체
JP5718449B2 (ja) * 2010-03-23 2015-05-13 カンブリオス テクノロジーズ コーポレイション 金属ナノワイヤを有する透明導体のエッチングパターン形成
JP4870836B1 (ja) * 2010-11-19 2012-02-08 日本写真印刷株式会社 狭額縁タッチ入力シートの製造方法
CN103080876A (zh) 2010-07-05 2013-05-01 Dic株式会社 带透明导电层的基体及其制造方法、以及触控面板用透明导电膜层叠体、触控面板
US20120247527A1 (en) 2010-12-21 2012-10-04 Alphabet Energy, Inc. Electrode structures for arrays of nanostructures and methods thereof
US9482693B2 (en) * 2011-02-04 2016-11-01 Shin-Etsu Polymer Co., Ltd. Capacitive sensor sheet and production method thereof
WO2012145157A1 (en) * 2011-04-15 2012-10-26 3M Innovative Properties Company Transparent electrode for electronic displays
JP2013077435A (ja) * 2011-09-30 2013-04-25 Oji Holdings Corp 導電性転写シートおよび導電性積層体
KR20130071863A (ko) 2011-12-21 2013-07-01 삼성전기주식회사 터치패널
KR101714286B1 (ko) * 2012-11-08 2017-03-08 알프스 덴키 가부시키가이샤 도전체 및 그 제조 방법
CN104838342B (zh) 2012-12-07 2018-03-13 3M创新有限公司 在基板上制作透明导体的方法
WO2014156489A1 (ja) * 2013-03-26 2014-10-02 株式会社カネカ 導電性フィルム基板、透明導電性フィルムおよびその製造方法、ならびにタッチパネル

Also Published As

Publication number Publication date
CN105453001B (zh) 2018-10-16
SG10201808518RA (en) 2018-10-30
BR112016002093A2 (pt) 2017-08-01
EP3028126A1 (en) 2016-06-08
KR20160036571A (ko) 2016-04-04
JP2016530622A (ja) 2016-09-29
US20160143153A1 (en) 2016-05-19
KR102254683B1 (ko) 2021-05-21
CN105453001A (zh) 2016-03-30
WO2015017143A1 (en) 2015-02-05
US9980394B2 (en) 2018-05-22
EP3028126A4 (en) 2017-01-25
EP3028126B1 (en) 2020-10-07
JP6426737B2 (ja) 2018-11-21

Similar Documents

Publication Publication Date Title
SG11201600591VA (en) Bonding electronic components to patterned nanowire transparent conductors
ZA201602716B (en) Wearable electronic device
EP3042251A4 (en) Wearable electronic device
EP3007528A4 (en) Bendable electronic device
AU353417S (en) Electronic device
BR302012003889S1 (pt) Configuração aplicada a câmera eletrônica
PT3022623T (pt) Caneta eletrónica
GB2516555B (en) Single element wire to board connector
SG11201604642YA (en) Transparent conductive multilayer assembly
GB2510133B (en) Conductive bonded composites
BR302013004577S1 (pt) Configuração aplicada a conector elétrico
EP3010128A4 (en) Electronic circuit
EP3087498A4 (en) Electronic device having two processors to process data
EP2975612A4 (en) HOUSING FOR ELECTRONIC DEVICE
SG11201508883VA (en) Electronic device
PL3055730T3 (pl) Elektroniczny eyebox
SG11201506221SA (en) Methods to incorporate silver nanowire-based transparent conductors in electronic devices
SG11201508087RA (en) Electronic device
GB201318514D0 (en) Flip case using nano suction to attach electronic devices
GB2518387B (en) Electronic circuit production
GB2512597B (en) Electronic devices
HK1206489B (en) Single element wire to board connector
GB201317173D0 (en) Electronic gift
BR302013006807S1 (pt) Configuração aplicada a cigarros eletrônicos
GB201309200D0 (en) LED driver circuit