JP2004039120A

JP2004039120A - Optical pickup, optical integrated element, light emitting/receiving element, and light emitting device

Info

Publication number: JP2004039120A
Application number: JP2002195420A
Authority: JP
Inventors: Kiyoshi Mano; 真能　清志; Kiyoshi Yamauchi; 山内　淨
Original assignee: Sony Corp
Current assignee: Sony Corp
Priority date: 2002-07-04
Filing date: 2002-07-04
Publication date: 2004-02-05

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical pickup capable of efficiently radiating heat generated in a semiconductor laser diode, an optical integrated element, a light emitting/receiving element, and a light emitting device. <P>SOLUTION: When a drive signal is supplied to the semiconductor laser diode 1204 through a 1st conductive layer 42 of a flexible substrate 40, the diode 1204 is driven and starts light emitting. Heat generated in the diode 1204 due to the light emitting is transmitted to a radiating plate 1202. The heat transmitted to the radiating plate 1202 is transmitted to a holder (pickup casing) 50 and radiated from the holder (pickup casing) 50 and the heat is transmitted to the 1st conductive layer 42 of the flexible substrate 40 through a side plate 1202A, further transmitted to the 2nd conductive layer 44 through a conductive area 46 and radiated from the 2nd conductive layer 44. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、光ピックアップ、光集積素子、受発光素子および発光デバイスに関する。
【０００２】
【従来の技術】
光ディスクドライブ装置には、近年、高密度化への要求と共に小型情報端末への搭載を前提とした小型化への要求が高まっており、その基幹デバイスである光ピックアップにおいても、小型化を追求した開発が活発に行なわれている。
光ピックアップは、例えば、半導体レーザダイオード、再生信号検出用ＰＤＩＣ（Ｐｈｏｔｏｄｉｏｄｅ　ＩＣ）、サーボ信号生成用ホログラム等を有する光集積素子が組み込まれて構成されている。
このような光集積素子は、小型軽量を特徴とする光ディスクドライブへ適用するため、および、近年の高密度化への要求に対応するため、その光源には短波長の青紫色半導体レーザダイオードが用いられるようになってきている。
【０００３】
【発明が解決しようとする課題】
このような青紫色半導体レーザダイオードは光ディスク面上でのビーム径を従来よりも小さく絞り込むことが出来ると言う特徴を持っているため、高密度化に大きく貢献するが、赤色レーザダイオードなどと比較すると、同じ光パワーを出力するために必要な投入電力が大きく、従って動作時のレーザダイオードからの発熱量が大きいという不利な面も併せ持っている。
また、光集積素子のように小型のデバイスにおいては、素子自体の熱容量が小さい為、青紫色半導体レーザダイオードを搭載した場合、かなり効率よく放熱を行なわせないと、著しい温度上昇が起こってしまうという問題があった。
本発明は、このような実状に鑑みてなされたものであり、その目的とするところは、半導体レーザダイオードで発生する熱を効率よく放熱することができる光ピックアップ、光集積素子、受発光素子および発光デバイスを提供することにある。
【０００４】
【課題を解決するための手段】
本発明の光ピックアップは、前記目的を達成するため、光ビームを出射する半導体レーザダイオードと、前記半導体レーザダイオードが取着された放熱材と、前記半導体レーザダイオードへの駆動信号、又は光検出手段からの出力信号用の配線パターンの少なくとも一方が設けられ前記放熱材に連結されたプリント基板と、光検出手段と、前記光ビームを光記録媒体に照射するとともに、前記照射された光ビームの前記光記録媒体での反射光ビームを前記光検出手段に導く光学系とを備える光ピックアップにおいて、前記プリント基板は、前記配線パターンを含んだ第１の導電層と、放熱用として設けられた第２の導電層とを有して構成され、前記放熱材と前記第２の導電層は熱伝達可能に連結されていることを特徴とする。
また、本発明の光集積素子は、光ビームを出射する半導体レーザダイオードと、前記半導体レーザダイオードが取着された放熱材と、光検出手段と、前記半導体レーザダイオードから出射された光ビームを光記録媒体に導くとともに、前記照射された光ビームの光記録媒体での反射光ビームを前記光検出手段に導く光路を形成する光学部品と、前記半導体レーザダイオードへの駆動信号、又は光検出手段からの出力信号用の配線パターンの少なくとも一方が設けられ前記放熱材に連結されたプリント基板と、前記半導体レーザダイオードと光検出手段と光学部品とが一体的に構成された光集積素子において、前記プリント基板は、前記配線パターンを含んだ第１の導電層と、放熱用として設けられた第２の導電層とを有して構成され、前記放熱材と前記第２の導電層は熱伝達可能に連結されていることを特徴とする。
また、本発明の受発光素子は、光ビームを出射する半導体レーザダイオードと、前記半導体レーザダイオードが取着された放熱材と、前記照射された光ビームの光記録媒体での反射光ビームを受光する光検出手段と、前記半導体レーザダイオードへの駆動信号、又は光検出手段からの出力信号用の配線パターンの少なくとも一方が設けられ前記放熱材に連結されたプリント基板とを備え、前記半導体レーザダイオードと光検出手段が一体的に構成された光集積素子において、前記プリント基板は、前記配線パターンを含んだ第１の導電層と、放熱用として設けられた第２の導電層とを有して構成され、前記放熱材と前記第２の導電層は熱伝達可能に連結されていることを特徴とする。
また、本発明の発光デバイスは、光ビームを出射する半導体レーザダイオードと、前記半導体レーザダイオードが取着された放熱材と、前記半導体レーザダイオードへの駆動信号の配線パターンが設けられ前記放熱材に連結されたプリント基板とを備えた発光デバイスにおいて、前記プリント基板は、前記配線パターンを含んだ第１の導電層と、放熱用として設けられた第２の導電層とを有して構成され、前記放熱材と前記第２の導電層は熱伝達可能に連結されていることを特徴とする。
【０００５】
そのため、本発明の光ピックアップ、光集積素子、受発光素子および発光デバイスによれば、発光動作に伴って半導体レーザダイオードで発生した熱は、放熱材に伝達される。前記放熱材に伝達された熱は、プリント基板の第２の導電層に伝達され、この第２の導電層で放熱される。
【０００６】
【発明の実施の形態】
以下、本発明による光集積素子および光ピックアップの実施の形態を図面に基づいて詳細に説明する。
図２は、本発明の第１の実施の形態による光ピックアップの構成図である。
光ピックアップ１０は、光集積素子１２、コリメータレンズ１４、アナモプリズム１６、エキスパンダ１８、１／４波長板２０、対物レンズ２２を備えており、これらの各部品がホルダ（ピックアップ筐体）５０（図１、図３参照）にマウントされて構成されている。
【０００７】
図３は光集積素子の拡大図である。
前記光集積素子１２は、放熱板１２０２、半導体レーザダイオード１２０４、立ち上げミラー１２０６、１／２波長板１２０８、モールド複合素子１２１０、積層プリズム１２１２、再生信号検出ＰＤＩＣ１２１４、フレキシブル基板４０（図１参照）などを含んで構成されている。
前記放熱板１２０２は、放熱性の良い材料から長さと長さよりも短い寸法の幅を有する矩形板状に形成され、本実施の形態では放熱板１２０２として銅板が用いられている。
前記半導体レーザダイオード１２０４は、放熱板１２０２の下面で長さ方向の中央よりもやや一方寄りの箇所にサブマウント１２０４Ａを介して半田付けによって取付けられている。
前記立ち上げミラー１２０６は、前記半導体レーザダイオード１２０４に臨む放熱板１２０２の下面箇所に設けられ、立ち上げミラー１２０６の近傍の放熱板１２０２箇所には開口１２０３が形成されている。
前記１／２波長板１２０８は、前記開口１２０３に臨む放熱板１２０２の上面箇所に取着されている。
前記再生信号検出ＰＤＩＣ１２１４は、前記放熱板１２０２の上面で長さ方向の中央よりもやや他方寄りの箇所に取着されている。
【０００８】
前記モールド複合素子１２１０は、前記１／２波長板１２０８および再生信号検出ＰＤＩＣ１２１４の上方に臨むように、その両端の脚部が前記放熱板１２０２の上面の長さ方向の両端に取着されて配設されている。
前記モールド複合素子１２１０の上面には、前記１／２波長板１２０８の上方に臨むようにＤＰＰ（Ｄｉｆｆｅｒｅｎｔｉａｌ　Ｐｕｓｈ−ｐｕｌｌ）サイドスポット生成用のグレーティング１２１０Ａが設けられている。
また、前記モールド複合素子１２１０の上面には、前記再生信号検出ＰＤＩＣ１２１４の上方に臨むようサーボ信号生成用のホログラム１２１０Ｂが設けられている。
前記積層プリズム１２１２は、偏光ビームスプリッタ１２１２Ａと全反射ミラー１２１２Ｂを含んで構成され、前記モールド複合素子１２１０の上面に取着されている。前記偏光ビームスプリッタ１２１２Ａは、グレーティング１２１０Ａの上方に臨み、全反射ミラー１２１２Ｂは、前記ホログラム１２１０Ｂの上方に臨んでいる。
【０００９】
前記光ピックアップ１０における光ビームの光路について説明すると、前記半導体レーザダイオード１２０４から出射された光ビームは、前記立ち上げミラー１２０４で反射されることにより９０度屈曲され、前記放熱板１２０２の開口１２０３を通って放熱板１２０２の下面から上面に導かれ、前記１／２波長板１２０８、グレーティング１２１０Ａ、偏光ビームスプリッタ１２１２Ａをこれらの順で通過して前記コリメータレンズ１４に導かれる。
前記コリメータレンズ１４によって平行光とされた光ビームは、前記アナモプリズム１６でビーム整形され、前記エキスパンダレンズ１８に導かれる。なお、前記エキスパンダレンズ１８は、本実施の形態では２群レンズよりなり、その２群レンズ間の距離を調整することにより、高ＮＡ対物レンズを用いた場合に顕著に現れる球面収差を補正するように構成されている。
前記エキスパンダレンズ１８を通過した光ビームは、前記１／４波長板２０及び２群レンズよりなる対物レンズ２２を通ることにより、光ディスク３０上の記録膜に集光される。
前記光ディスク３０上の相変化膜の反射率変化により光強度変調された反射光ビームは、上述と同じ光路を通って前記光集積素子１２に導かれる。
すなわち、前記反射光ビームは、前記コリメータレンズ１４を介して積層プリズム１２１２に入射され偏光ビームスプリッタ１２１２Ａ、全反射ミラー１２１２Ｂで反射され前記ホログラム１２１０Ｂによってメインビームに加えて２つのサイドビームが生成されこれら３つのビームが前記再生信号検出ＰＤＩＣ１２１４に入射される。
【００１０】
図１（Ａ）は放熱板とフレキシブル基板とが連結された状態を示す平面図、（Ｂ）は側面図、図４（Ａ）はフレキシブル基板を一方の面から見た図、（Ｂ）はフレキシブル基板を他方の面から見た図、図５はフレキシブル基板の断面図である。
図１（Ａ）、（Ｂ）に示すように、本実施の形態では、前記放熱板１２０２の幅方向の両側にそれぞれフレキシブル基板４０が取着されている。
図５に示すように、前記各フレキシブル基板４０は、絶縁材料４８からなる板材の内部に第１の導電層４２と第２の導電層４４とが前記板材の厚さ方向に間隔をおいて配置されることで構成されている。
前記第１の導電層４２は、前記半導体レーザダイオードに駆動電流を供給するための配線パターン４２０２、前記再生信号検出ＰＤＩＣ１２１４で検出された検出信号の伝達を行なうための配線パターン４２０４、グランドパターン４２０６を含んで構成されている。
また、このような駆動信号および検出信号の授受は、前記フレキシブル基板４０に接続される外部回路との間で行なわれる。
前記第２の導電層４４は、前記フレキシブル基板４０のほぼ全域にわたって矩形状に広がるグランドパターン４４０２から構成されている。
前記第２の導電層４４の面積は前記第１の導電層４２の面積よりも大きな値となり、前記第２の導電層４４の厚さは前記第１の導電層４２の厚さよりも大きな値となるように形成されている。
図４、図５に示すように、第２の導電層４４のグランドパターン４４０２と、前記第１の導電層４２のグランドパターン４２０６とは、円柱状の導通領域４６を介して電気的に接続され、かつ、熱伝達可能に連結されている。
また、前記第１の導電層４２の配線パターン４２０２、４２０４、グランドパターン４２０６の長手方向の端部のそれぞれは接続端子４２０２Ａ、４２０４Ａ、４２０６Ａとして構成され、これら各接続端子４２０２Ａ、４２０４Ａ、４２０６Ａの表面には前記絶縁材料４８が形成されておらず、外部に露出している。
【００１１】
図１（Ａ）、（Ｂ）に示すように、前記放熱板１２０２の幅方向の両側で長さ方向の中間部にはサイドプレート１２０２Ａが形成され、各サイドプレート１２０２Ａは下方に延在し、各フレキシブル基板４０の第１の導電層４２のグランドパターン４２０６の接続端子４２０６Ａに半田付けによって接続されている。
したがって、前記放熱板１２０２と前記第２の導電層４４は前記第１の導電層４２を介して電気的に接続され、かつ、熱伝達可能に連結されている。
また、前記第２の導電層４４のグランドパターン４４０２は、前記フレキシブル基板４０が接続される前記外部回路によってグランド電位に接続されている。したがって、第２の導電層４４のグランドパターン４４０２と、該グランドパターン４４０２に接続された第１の導電層４２のグランドパターン４２０６と、該グランドパターン４２０６に接続された放熱板１２０２は、全てグランド電位に保持されることになる。
【００１２】
各フレキシブル基板４０の第１の導電層４２のパターン４２０２、４２０４の接続端子４２０２Ａのそれぞれにはリードピン４７が設けられ、各リードピン４７と前記半導体レーザダイオード１２０４の端子の間、および、各リードピン４７と前記再生信号検出ＰＤＩＣ１２１４の端子との間はワイヤ４８により接続されている。
また、前記放熱板１２０２の上面の長さ方向の両端箇所から前記ホルダ（ピックアップ筐体）５０がそれぞれ立設され、放熱板１２０２と前記ホルダ（ピックアップ筐体）５０は熱伝達可能に連結されている。
【００１３】
本実施の形態においては、前記光集積素子１２、コリメータレンズ１４、アナモプリズム１６、エキスパンダ１８、１／４波長板２０、対物レンズ２２によって特許請求の範囲の光学系が構成されている。
また、前記立ち上げミラー１２０６、１／２波長板１２０８、モールド複合素子１２１０、積層プリズム１２１２によって特許請求の範囲の光学部品が構成されている。
また、前記放熱板１２０２によって特許請求の範囲の放熱材が構成され、前記フレキシブル基板４０によって特許請求の範囲のプリント基板が構成されている。
【００１４】
このように構成された光ピックアップ１０および光集積素子１２の作用について説明する。
前記半導体レーザダイオード１２０４に前記フレキシブル基板４０の第１の導電層４２を介して駆動信号が供給されると、該半導体レーザダイオード１２０４が駆動され発光動作を行う。
この発光動作に伴って半導体レーザダイオード１２０４で発生した熱は、放熱板１２０２に伝達される。前記放熱板１２０２に伝達された熱は、前記ホルダ（ピックアップ筐体）５０に伝達されて該ホルダ（ピックアップ筐体）５０で放熱されるとともに、前記サイドプレート１２０２Ａを介してフレキシブル基板４０の第１の導電層４２に伝達され、さらに前記導通領域４６を介して前記第２の導電層４４に伝達され、第２の導電層４４で放熱される。
【００１５】
したがって、本実施の形態によれば、半導体レーザダイオード１２０４で発生した熱が放熱材１２０２に伝達された後、該放熱板１２０２から第１の導電層４２から第２の導電層４４に伝達されて第２の導電層４４で放熱され、この放熱が行なわれる第２の導電層４４は、前記第１の導電層４２の面積よりも大きく、前記フレキシブル基板４０のほぼ全域にわたって広がり放熱面積が大きいので、放熱効果を向上する上で有利である。
また、第２の導電層４４の厚さを前記第１の導電層４２の厚さよりも大きな値としたことにより、第２の導電層４４内部における熱の伝達効率を上げることができ、放熱効果を向上する上で有利となる。
また、前記第２の導電層４４は、グランド電位に接続されているため、高周波ノイズの影響を抑制する作用も奏される。
【００１６】
次に、第２の実施の形態について説明する。
第２の実施の形態が第１の実施の形態と異なるのは、フレキシブル基板の第２の導電層に、前記放熱材に加え、別の放熱材が熱伝達可能に連結されている点である。
図６（Ａ）は第２の実施の形態におけるフレキシブル基板を一方の面から見た図、（Ｂ）はフレキシブル基板を他方の面から見た図、（Ｃ）は第２の実施の形態における光ピックアップの組立図である。図６において第１の実施の形態と同様の部分には同一の符号を付して説明する。
図６（Ｂ）に示すように、フレキシブル基板４０Ａの長さ方向の中間箇所において第２導電層４４の表面に絶縁材料４８を形成しない連結部４９が設けられている。
そして、図６（Ｃ）に示すように、前記連結部４９の箇所には銅製の放熱材５２が半田付けによって熱伝達可能に連結されている。
光集積素子１２の放熱板１２０２は第１の実施の形態と同様に前記ホルダ（ピックアップ筐体）５０に熱伝達可能に連結され、前記放熱材５２は銀ペーストなどを介して前記ホルダ（ピックアップ筐体）５０に熱伝達可能に連結される。
前記ホルダ（ピックアップ筐体）５０には回路基板５４が設けられ、フレキシブル基板４０Ａの光集積素子１２と反対側の端部と前記回路基板５４はフレキシブル基板用コネクタを介して接続される。前記回路基板５４は、前述した外部回路を構成するものであり、前記フレキシブル基板４０Ａを介して、半導体レーザダイオード１２０４に駆動信号を供給するとともに前記再生信号検出ＰＤＩＣ１２１４の再生信号を入力するように構成されている。
【００１７】
このように構成された第２の実施の形態によれば、前記半導体レーザダイオード１２０４で発生した熱を、前記第２導電層４４の連結部４９から放熱部５２に伝達して該放熱部５２で放熱し、さらに該放熱材５２からホルダ（ピックアップ筐体）５０に熱を伝達して該ホルダ（ピックアップ筐体）５０で放熱することができるので、放熱効果をより向上させる上で有利となる。
本実施例では、放熱部５２を介して該ホルダ（ピックアップ筐体）５０に対して放熱させているが、放熱部５２を介してドライブシャーシ等、熱容量の大きい別の部材に対して放熱させても同様の効果が得られる。
【００１８】
なお、第１、第２の実施の形態においては、放熱板１２０２を第１の導電層４２を介して第２の導電層４４に熱伝達可能に連結したが、放熱板１２０２を第２の導電層４４に熱伝達可能に直接接続してもよい。この場合には、前記導通領域４６を設ける必要がないのでフレキシブル基板４０の構成を簡素化できる効果がある。
また、第１、第２の実施の形態においては、前記半導体レーザダイオード１２０４をサブマウント１２０４Ａを介して放熱板１２０２に取着したが、前記サブマウント１２０４Ａを用いることなく半導体レーザダイオード１２０４を直接放熱板１２０２に取着してもよい。
また、第１、第２の実施の形態においては、２つの導電層を持つプリント基板を用いているが、第１の導電層、又は第２の導電層が、さらに複数の導電層から構成されていても良い。
また、本発明は、半導体レーザダイオードと、前記半導体レーザダイオードが取着された放熱材と、前記照射された光ビームの光記録媒体での反射光ビームを受光する光検出手段と、前記半導体レーザダイオードへの駆動信号、又は光検出手段からの出力信号用の配線パターンの少なくとも一方が設けられ前記放熱材に連結されたプリント基板とを備え、前記半導体レーザダイオードと光検出手段が一体的に構成された光集積素子に適用可能である。
また、本発明は、半導体レーザダイオードと、前記半導体レーザダイオードが取着された放熱材と、前記半導体レーザダイオードへの駆動信号の配線パターンが設けられ前記放熱材に連結されたプリント基板とを備えた発光デバイスにも適用可能である。
【００１９】
【発明の効果】
以上説明したように本発明によれば、半導体レーザダイオードで発生する熱を効率よく放熱することができる光ピックアップ、光集積素子、受発光素子および発光デバイスを提供することができる。
【図面の簡単な説明】
【図１】（Ａ）は放熱板とフレキシブル基板とが連結された状態を示す平面図、（Ｂ）は側面図である。
【図２】本発明の第１の実施の形態による光ピックアップの構成図である。
【図３】光集積素子の拡大図である。
【図４】フレキシブル基板を一方の面から見た図、（Ｂ）はフレキシブル基板を他方の面から見た図である。
【図５】フレキシブル基板の断面図である。
【図６】（Ａ）は第２の実施の形態におけるフレキシブル基板を一方の面から見た図、（Ｂ）はフレキシブル基板を他方の面から見た図、（Ｃ）は第２の実施の形態における光ピックアップの組立図である。
【符号の説明】
１０……光ピックアップ、１２……光集積素子、１２０２……放熱板、１２０４……半導体レーザダイオード、２２……対物レンズ、４０……フレキシブル基板、４２……第１の導電層、４４……第２の導電層。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical pickup, an optical integrated element, a light emitting / receiving element, and a light emitting device.
[0002]
[Prior art]
In recent years, there has been an increasing demand for optical disc drive devices to be miniaturized assuming that they are mounted on small information terminals, as well as to higher densities. Active development is taking place.
The optical pickup includes, for example, an integrated optical device having a semiconductor laser diode, a PDIC (Photodiode IC) for detecting a reproduction signal, a hologram for generating a servo signal, and the like.
In order to apply such an optical integrated device to an optical disk drive characterized by its small size and light weight, and to respond to recent demands for higher density, a short-wavelength blue-violet semiconductor laser diode is used as its light source. It is becoming possible.
[0003]
[Problems to be solved by the invention]
Such a blue-violet semiconductor laser diode has the feature that the beam diameter on the optical disk surface can be narrowed down as compared with the conventional one, so it greatly contributes to high density, but compared with red laser diode etc. In addition, there is a disadvantage in that the input power required to output the same optical power is large, and thus the amount of heat generated from the laser diode during operation is large.
Also, in a small device such as an optical integrated device, the heat capacity of the device itself is small, and if a blue-violet semiconductor laser diode is mounted, a significant temperature rise will occur unless heat is dissipated fairly efficiently. There was a problem.
The present invention has been made in view of such circumstances, and an object of the present invention is to provide an optical pickup, an optical integrated device, a light receiving / emitting device, and a light emitting device that can efficiently radiate heat generated by a semiconductor laser diode. It is to provide a light emitting device.
[0004]
[Means for Solving the Problems]
In order to achieve the above object, an optical pickup according to the present invention includes a semiconductor laser diode for emitting a light beam, a heat dissipating member to which the semiconductor laser diode is attached, a drive signal to the semiconductor laser diode, or light detection means. A printed circuit board provided with at least one of the wiring patterns for output signals from, and connected to the heat dissipating material, a light detection unit, and irradiating the optical beam to the optical recording medium, An optical pickup comprising: an optical system for guiding a light beam reflected by an optical recording medium to the light detection means; wherein the printed circuit board includes a first conductive layer including the wiring pattern and a second conductive layer provided for heat radiation. Wherein the heat dissipating material and the second conductive layer are connected so that heat can be transferred.
Further, the optical integrated device of the present invention comprises a semiconductor laser diode that emits a light beam, a heat radiating member to which the semiconductor laser diode is attached, light detection means, and a light beam emitted from the semiconductor laser diode. An optical component that forms an optical path for guiding the reflected light beam of the irradiated light beam from the optical recording medium to the light detection means, and a drive signal to the semiconductor laser diode, or a light detection means. A printed circuit board provided with at least one of the output signal wiring patterns and connected to the heat dissipating material; and an optical integrated device in which the semiconductor laser diode, the light detecting means, and the optical component are integrally formed. The substrate includes a first conductive layer including the wiring pattern, and a second conductive layer provided for heat dissipation. Wherein the wood second conductive layer is characterized in that it is linked to heat transfer.
In addition, the light emitting and receiving element of the present invention includes a semiconductor laser diode that emits a light beam, a heat radiating material to which the semiconductor laser diode is attached, and a light receiving member that receives the irradiated light beam reflected by an optical recording medium. And a printed circuit board provided with at least one of a wiring pattern for a driving signal to the semiconductor laser diode or an output signal from the light detecting means and connected to the heat radiating material. And an optical integrated device in which the light detection means is integrally formed, wherein the printed board has a first conductive layer including the wiring pattern, and a second conductive layer provided for heat dissipation. The heat dissipation material and the second conductive layer are connected so that heat can be transferred.
Further, the light emitting device of the present invention is provided with a semiconductor laser diode that emits a light beam, a heat radiation material to which the semiconductor laser diode is attached, and a wiring pattern of a drive signal to the semiconductor laser diode, wherein the heat radiation material is provided. In a light emitting device including a connected printed board, the printed board is configured to include a first conductive layer including the wiring pattern and a second conductive layer provided for heat dissipation, The heat dissipating material and the second conductive layer are connected so that heat can be transferred.
[0005]
Therefore, according to the optical pickup, the optical integrated device, the light receiving / emitting element, and the light emitting device of the present invention, the heat generated in the semiconductor laser diode during the light emitting operation is transmitted to the heat radiating material. The heat transferred to the heat dissipating material is transferred to the second conductive layer of the printed circuit board, and is radiated by the second conductive layer.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of an optical integrated device and an optical pickup according to the present invention will be described in detail with reference to the drawings.
FIG. 2 is a configuration diagram of the optical pickup according to the first embodiment of the present invention.
The optical pickup 10 includes an optical integrated element 12, a collimator lens 14, an anamorphic prism 16, an expander 18, a quarter-wave plate 20, and an objective lens 22, and these components are used as a holder (pickup housing) 50 ( (See FIGS. 1 and 3).
[0007]
FIG. 3 is an enlarged view of the optical integrated device.
The optical integrated device 12 includes a heat sink 1202, a semiconductor laser diode 1204, a rising mirror 1206, a half-wave plate 1208, a molded composite device 1210, a laminated prism 1212, a reproduction signal detection PDIC 1214, and a flexible substrate 40 (see FIG. 1). It is comprised including.
The heat radiating plate 1202 is formed in a rectangular plate shape having a length and a width shorter than the length from a material having good heat radiating properties. In the present embodiment, a copper plate is used as the heat radiating plate 1202.
The semiconductor laser diode 1204 is mounted on the lower surface of the heat radiating plate 1202 by soldering via a submount 1204A at a position slightly closer to one side than the center in the length direction.
The rising mirror 1206 is provided on the lower surface of the heat sink 1202 facing the semiconductor laser diode 1204, and an opening 1203 is formed in the heat sink 1202 near the rising mirror 1206.
The half-wave plate 1208 is attached to the upper surface of the heat sink 1202 facing the opening 1203.
The reproduction signal detection PDIC 1214 is mounted on the upper surface of the heat sink 1202 at a position slightly closer to the other side than the center in the length direction.
[0008]
The mold composite element 1210 is provided with legs at both ends thereof attached to the longitudinal ends of the upper surface of the heat sink 1202 so as to face above the half-wave plate 1208 and the reproduction signal detection PDIC 1214. Is established.
A grating 1210A for generating a differential push-pull (DPP) side spot is provided on the upper surface of the mold composite element 1210 so as to face above the half-wave plate 1208.
Also, a hologram 1210B for generating a servo signal is provided on the upper surface of the mold composite element 1210 so as to face above the reproduction signal detection PDIC 1214.
The laminated prism 1212 includes a polarizing beam splitter 1212A and a total reflection mirror 1212B, and is attached to the upper surface of the molded composite element 1210. The polarizing beam splitter 1212A faces above the grating 1210A, and the total reflection mirror 1212B faces above the hologram 1210B.
[0009]
The optical path of the light beam in the optical pickup 10 will be described. The light beam emitted from the semiconductor laser diode 1204 is bent by 90 degrees by being reflected by the rising mirror 1204, and passes through the opening 1203 of the heat sink 1202. The light is guided from the lower surface of the heat radiating plate 1202 to the upper surface, passes through the 波長 wavelength plate 1208, the grating 1210A, and the polarizing beam splitter 1212A in this order, and is guided to the collimator lens.
The light beam collimated by the collimator lens 14 is shaped by the anamorphic prism 16 and guided to the expander lens 18. In the present embodiment, the expander lens 18 is composed of a two-group lens, and the distance between the two-group lenses is adjusted to correct spherical aberration that appears remarkably when a high NA objective lens is used. It is configured as follows.
The light beam that has passed through the expander lens 18 passes through the quarter-wave plate 20 and the objective lens 22 composed of a second group lens, and is condensed on a recording film on the optical disk 30.
The reflected light beam whose light intensity is modulated by the change in the reflectance of the phase change film on the optical disk 30 is guided to the optical integrated device 12 through the same optical path as described above.
That is, the reflected light beam enters the laminated prism 1212 via the collimator lens 14 and is reflected by the polarizing beam splitter 1212A and the total reflection mirror 1212B. The hologram 1210B generates two side beams in addition to the main beam. Three beams are incident on the reproduction signal detection PDIC 1214.
[0010]
1A is a plan view showing a state in which a heat sink and a flexible board are connected, FIG. 1B is a side view, FIG. 4A is a view of the flexible board viewed from one side, and FIG. FIG. 5 is a cross-sectional view of the flexible substrate when the flexible substrate is viewed from the other surface.
As shown in FIGS. 1A and 1B, in the present embodiment, flexible boards 40 are attached to both sides of the heat sink 1202 in the width direction.
As shown in FIG. 5, each of the flexible substrates 40 has a first conductive layer 42 and a second conductive layer 44 arranged inside a plate made of an insulating material 48 at intervals in the thickness direction of the plate. It is configured to be.
The first conductive layer 42 includes a wiring pattern 4202 for supplying a drive current to the semiconductor laser diode, a wiring pattern 4204 for transmitting a detection signal detected by the reproduction signal detection PDIC 1214, and a ground pattern 4206. It is comprised including.
The transmission and reception of the drive signal and the detection signal are performed with an external circuit connected to the flexible substrate 40.
The second conductive layer 44 is formed of a ground pattern 4402 that extends in a rectangular shape over substantially the entire area of the flexible substrate 40.
The area of the second conductive layer 44 is larger than the area of the first conductive layer 42, and the thickness of the second conductive layer 44 is larger than the thickness of the first conductive layer 42. It is formed so that it becomes.
As shown in FIGS. 4 and 5, the ground pattern 4402 of the second conductive layer 44 and the ground pattern 4206 of the first conductive layer 42 are electrically connected to each other via a cylindrical conductive region 46. And are connected so that heat can be transmitted.
The longitudinal ends of the wiring patterns 4202 and 4204 of the first conductive layer 42 and the ground pattern 4206 are respectively formed as connection terminals 4202A, 4204A and 4206A, and the surfaces of these connection terminals 4202A, 4204A and 4206A are formed. Is not formed with the insulating material 48 and is exposed to the outside.
[0011]
As shown in FIGS. 1 (A) and 1 (B), side plates 1202A are formed at both sides in the width direction of the heat radiating plate 1202 and in the middle part in the length direction, and each side plate 1202A extends downward. Each flexible substrate 40 is connected to the connection terminal 4206A of the ground pattern 4206 of the first conductive layer 42 by soldering.
Therefore, the heat radiating plate 1202 and the second conductive layer 44 are electrically connected via the first conductive layer 42 and are connected so that heat can be transmitted.
The ground pattern 4402 of the second conductive layer 44 is connected to a ground potential by the external circuit to which the flexible board 40 is connected. Therefore, the ground pattern 4402 of the second conductive layer 44, the ground pattern 4206 of the first conductive layer 42 connected to the ground pattern 4402, and the heat sink 1202 connected to the ground pattern 4206 are all ground potentials. Will be held.
[0012]
Each of the connection terminals 4202A of the patterns 4202 and 4204 of the first conductive layer 42 of each flexible substrate 40 is provided with a lead pin 47, between each lead pin 47 and the terminal of the semiconductor laser diode 1204, and between each lead pin 47 and The terminal of the reproduction signal detection PDIC 1214 is connected by a wire 48.
Also, the holders (pickup housing) 50 are erected from both ends in the longitudinal direction of the upper surface of the heat sink 1202, respectively, and the heat sink 1202 and the holder (pickup housing) 50 are connected so as to be able to transfer heat. I have.
[0013]
In the present embodiment, the optical integrated device 12, the collimator lens 14, the anamorphic prism 16, the expander 18, the quarter-wave plate 20, and the objective lens 22 constitute an optical system according to the claims.
The rising mirror 1206, the half-wave plate 1208, the molded composite element 1210, and the laminated prism 1212 constitute an optical component according to the present invention.
The radiator plate 1202 constitutes a radiator of the present invention, and the flexible substrate 40 constitutes a printed circuit board of the present invention.
[0014]
The operation of the optical pickup 10 and the optical integrated device 12 thus configured will be described.
When a driving signal is supplied to the semiconductor laser diode 1204 via the first conductive layer 42 of the flexible substrate 40, the semiconductor laser diode 1204 is driven to perform a light emitting operation.
The heat generated by the semiconductor laser diode 1204 due to the light emitting operation is transmitted to the heat sink 1202. The heat transmitted to the heat radiating plate 1202 is transmitted to the holder (pickup housing) 50 and radiated by the holder (pickup housing) 50, and the first of the flexible substrate 40 via the side plate 1202 </ b> A. Is transmitted to the second conductive layer 44 via the conductive region 46 and is radiated by the second conductive layer 44.
[0015]
Therefore, according to the present embodiment, after the heat generated in semiconductor laser diode 1204 is transmitted to heat radiating material 1202, it is transmitted from first heat conductive layer 42 to second conductive layer 44 from heat radiating plate 1202. The heat is radiated by the second conductive layer 44, and the second conductive layer 44 radiating the heat is larger than the area of the first conductive layer 42 and spreads over almost the entire area of the flexible substrate 40, so that the heat radiating area is large. This is advantageous in improving the heat radiation effect.
Further, by setting the thickness of the second conductive layer 44 to a value larger than the thickness of the first conductive layer 42, the efficiency of heat transfer inside the second conductive layer 44 can be increased, and the heat dissipation effect can be improved. This is advantageous in improving.
Further, since the second conductive layer 44 is connected to the ground potential, an effect of suppressing the influence of high-frequency noise is also exerted.
[0016]
Next, a second embodiment will be described.
The second embodiment is different from the first embodiment in that, in addition to the heat dissipating material, another heat dissipating material is connected to the second conductive layer of the flexible substrate so as to allow heat transfer. .
FIG. 6A is a diagram of the flexible substrate according to the second embodiment as viewed from one surface, FIG. 6B is a diagram of the flexible substrate as viewed from the other surface, and FIG. 6C is a diagram of the second embodiment. It is an assembly drawing of an optical pickup. In FIG. 6, the same parts as those in the first embodiment are denoted by the same reference numerals and described.
As shown in FIG. 6B, a connecting portion 49 in which the insulating material 48 is not formed is provided on the surface of the second conductive layer 44 at an intermediate position in the length direction of the flexible substrate 40A.
As shown in FIG. 6C, a heat radiating member 52 made of copper is connected to the connecting portion 49 so as to be able to transfer heat by soldering.
The heat radiating plate 1202 of the optical integrated device 12 is connected to the holder (pickup housing) 50 so as to be able to conduct heat similarly to the first embodiment, and the heat radiating material 52 is connected to the holder (pickup housing) via silver paste or the like. Body) 50 so as to be able to transfer heat.
The holder (pickup housing) 50 is provided with a circuit board 54, and the end of the flexible board 40A on the opposite side to the optical integrated device 12 and the circuit board 54 are connected via a flexible board connector. The circuit board 54 constitutes the above-described external circuit, and is configured to supply a drive signal to the semiconductor laser diode 1204 and input a reproduction signal of the reproduction signal detection PDIC 1214 via the flexible substrate 40A. Have been.
[0017]
According to the second embodiment configured as described above, the heat generated by the semiconductor laser diode 1204 is transmitted from the connecting portion 49 of the second conductive layer 44 to the heat radiating portion 52, and the heat is radiated by the heat radiating portion 52. Since heat can be dissipated and further transferred from the heat dissipating material 52 to the holder (pickup housing) 50 and dissipated by the holder (pickup housing) 50, this is advantageous in further improving the heat radiation effect.
In the present embodiment, heat is radiated to the holder (pickup housing) 50 via the heat radiating portion 52, but is radiated to another member having a large heat capacity such as a drive chassis via the heat radiating portion 52. Has the same effect.
[0018]
In the first and second embodiments, the heat radiating plate 1202 is connected to the second conductive layer 44 via the first conductive layer 42 so that heat can be transferred. It may be connected directly to the layer 44 in a heat-transferable manner. In this case, since it is not necessary to provide the conductive region 46, there is an effect that the configuration of the flexible substrate 40 can be simplified.
In the first and second embodiments, the semiconductor laser diode 1204 is attached to the heat sink 1202 via the submount 1204A. However, the semiconductor laser diode 1204 is directly radiated without using the submount 1204A. It may be attached to the plate 1202.
Further, in the first and second embodiments, a printed circuit board having two conductive layers is used, but the first conductive layer or the second conductive layer is further formed of a plurality of conductive layers. May be.
Also, the present invention provides a semiconductor laser diode, a heat radiating member to which the semiconductor laser diode is attached, light detecting means for receiving a reflected light beam of the irradiated light beam on an optical recording medium, and the semiconductor laser. A printed circuit board provided with at least one of a wiring pattern for a drive signal to the diode or an output signal from the light detecting means and connected to the heat radiating material, wherein the semiconductor laser diode and the light detecting means are integrally formed. The present invention can be applied to an integrated optical device.
Further, the present invention includes a semiconductor laser diode, a heat radiator to which the semiconductor laser diode is attached, and a printed circuit board provided with a wiring pattern of a drive signal to the semiconductor laser diode and connected to the heat radiator. It can also be applied to light emitting devices.
[0019]
【The invention's effect】
As described above, according to the present invention, it is possible to provide an optical pickup, an optical integrated element, a light receiving / emitting element, and a light emitting device that can efficiently radiate heat generated by a semiconductor laser diode.
[Brief description of the drawings]
FIG. 1A is a plan view showing a state in which a heat sink and a flexible board are connected, and FIG. 1B is a side view.
FIG. 2 is a configuration diagram of an optical pickup according to the first embodiment of the present invention.
FIG. 3 is an enlarged view of the optical integrated device.
FIG. 4 is a diagram of the flexible substrate as viewed from one surface, and FIG. 4B is a diagram of the flexible substrate as viewed from the other surface.
FIG. 5 is a sectional view of a flexible substrate.
6A is a diagram of the flexible substrate according to the second embodiment viewed from one surface, FIG. 6B is a diagram of the flexible substrate viewed from the other surface, and FIG. 6C is a diagram of the second embodiment. It is an assembly drawing of the optical pickup in a form.
[Explanation of symbols]
Reference Signs List 10 optical pickup 12 optical integrated device 1202 heat sink 1204 semiconductor laser diode 22 objective lens 40 flexible substrate 42 first conductive layer 44 A second conductive layer.

Claims

A semiconductor laser diode for emitting a light beam;
A radiator to which the semiconductor laser diode is attached,
A drive signal to the semiconductor laser diode, or a printed circuit board provided with at least one of a wiring pattern for an output signal from a photodetector and connected to the heat radiating material;
Light detection means;
Irradiating the optical beam to the optical recording medium, and an optical system that guides the reflected light beam of the illuminated light beam on the optical recording medium to the light detection means,
The printed board includes a first conductive layer including the wiring pattern, and a second conductive layer provided for heat dissipation.
The heat dissipating material and the second conductive layer are connected so as to be able to transfer heat.
An optical pickup characterized in that:

A semiconductor laser diode for emitting a light beam;
A radiator to which the semiconductor laser diode is attached,
Light detection means;
An optical component that guides a light beam emitted from the semiconductor laser diode to an optical recording medium and forms an optical path that guides a reflected light beam of the irradiated light beam on the optical recording medium to the light detection unit,
A drive signal to the semiconductor laser diode, or a printed circuit board provided with at least one of a wiring pattern for an output signal from a photodetector and connected to the heat radiating material;
An optical integrated device in which the semiconductor laser diode, the light detection means, and the optical component are integrally formed,
The printed board includes a first conductive layer including the wiring pattern, and a second conductive layer provided for heat dissipation.
The heat dissipating material and the second conductive layer are connected so as to be able to transfer heat.
An optical integrated device, comprising:

A semiconductor laser diode for emitting a light beam;
A radiator to which the semiconductor laser diode is attached,
Light detection means for receiving a light beam reflected by the optical recording medium of the irradiated light beam,
A drive signal to the semiconductor laser diode, or a printed circuit board provided with at least one of a wiring pattern for an output signal from a photodetector and connected to the heat dissipating material,
In the optical integrated device in which the semiconductor laser diode and the light detecting means are integrally formed,
The printed board includes a first conductive layer including the wiring pattern, and a second conductive layer provided for heat dissipation.
The heat dissipating material and the second conductive layer are connected so as to be able to transfer heat.
A light receiving and emitting element characterized by the above-mentioned.

A semiconductor laser diode for emitting a light beam;
A radiator to which the semiconductor laser diode is attached,
In a light emitting device comprising a printed circuit board provided with a wiring pattern of a drive signal to the semiconductor laser diode and connected to the heat radiating material,
The printed board includes a first conductive layer including the wiring pattern, and a second conductive layer provided for heat dissipation.
The heat dissipating material and the second conductive layer are connected so as to be able to transfer heat.
A light emitting device characterized by the above-mentioned.

The optical pickup according to claim 1, wherein the connection between the heat radiating material and the second conductive layer is performed through the first conductive layer. A light emitting / receiving element according to claim 3 or a light emitting device according to claim 4.

The printed circuit board is configured by arranging the first conductive layer and the second conductive layer at an interval in a thickness direction of the plate material inside a plate material made of an insulating material; Between the conductive layer and the second conductive layer, a conductive region made of a conductive material connecting the conductive layers is provided, and the heat dissipation material and the second conductive layer are connected to the first conductive layer and the conductive layer. The optical pickup according to claim 1, wherein the optical pickup is performed via a region, the optical integrated device according to claim 2, the light emitting / receiving element according to claim 3, or the light emitting / receiving device according to claim 4. Light emitting device.

3. The optical pickup according to claim 1, wherein the area of the second conductive layer is larger than the area of the first conductive layer. A light emitting / receiving element according to claim 3 or a light emitting device according to claim 4.

The optical pickup according to claim 1, wherein the second conductive layer extends over substantially the entire area of the printed circuit board, the optical integrated device according to claim 2, or the light emitting / receiving element according to claim 3, or the claim. 5. The light emitting device according to 4.

3. The optical pickup according to claim 1, wherein the thickness of the second conductive layer is larger than the thickness of the first conductive layer. An element, a light emitting / receiving element according to claim 3, or a light emitting device according to claim 4.

5. The optical pickup according to claim 1, wherein the second conductive layer is connected to a ground potential, an optical integrated device according to claim 2, a light emitting / receiving element according to claim 3, or a light emitting / receiving element according to claim 4. Light emitting device.

3. The optical pickup according to claim 1, wherein a heat radiation material different from the heat radiation material is connected to the second conductive layer so that heat can be transmitted. The light emitting and receiving element according to claim 3 or the light emitting device according to claim 4.