JP3932068B2

JP3932068B2 - Image reading device

Info

Publication number: JP3932068B2
Application number: JP32057397A
Authority: JP
Inventors: 一男佐藤; 勝幸塚原
Original assignee: Citizen Electronics Co Ltd
Current assignee: Citizen Electronics Co Ltd
Priority date: 1997-11-07
Filing date: 1997-11-07
Publication date: 2007-06-20
Anticipated expiration: 2017-11-07
Also published as: JPH11146132A

Description

【０００１】
【発明の属する技術分野】
本発明はコンピュータ、ファクシミリ、複写機等の入力装置として、原稿の画像を読み取る画像読取装置に関する。
【０００２】
【従来の技術】
画像読取装置は画像の入力装置として、操作性、汎用性に優れ、近年ＯＡ機器、情報機器等の分野で広く用いられている。特に近年、家庭用ファクシミリ装置の需要が高まり、これに用いられる画像読取装置として小型で使い易いものが要求されているところから光源に発光ダイオード（以下「ＬＥＤ」という。）アレイを用いた密着型画像読取装置が普及しつつある。図８は従来のかかる密着型画像読取装置の断面図であり、その概要を説明する
【０００３】
図９に示すように、密着型画像読取装置は光電変換を行うセンサー画素が複数配列された原稿読取受光素子２１と、保護膜２２と、これが実装された基板２３とからなる成る受光素子アレイ２４と、原稿を照射する線状光源であるＬＥＤアレイ２５と、原稿２９の像を受光部である前記受光素子アレイ２４に結像するレンズアレイ２６と、原稿２９を載置する透明板２７と、これらの部材を支持する外装ケース２８より構成されている。
【０００４】
上記密着型画像読取装置における動作は、ＬＥＤアレイ２５により原稿面を照射し、前記原稿面の読み取りライン上の拡散反射光をレンズアレイ２６により受光素子アレイ上に結像し、前記反射光のもつ原稿２９の濃淡情報、即ち光の強弱を受光素子アレイ２４における個々のセンサー画素が電気信号に変換し、シリアル又はパラレルの信号出力として読み取りラインごとに送り出す。そして、前記原稿２９とセンサー画素列との相対位置をラインと垂直方向に移動させて、前記ラインごとのデータ送出を繰り返すことにより、２次元画像情報を時系列電気信号に変換する。
【０００５】
しかしながら、前述の密着型画像読取装置には次のような問題がある。その一つは、光源に関する問題である。すなわち、読み取り精度を上げるため、ＬＥＤアレイ２５のＬＥＤの数を多くし、密に配列することにより、その照明する原稿面の照度を実質的に均一化するようにすると、ＬＥＤの使用個数が多いため部品費が高くなり、コストの低減が困難となる。
【０００６】
問題点の他の一つは、レンズアレイに関する問題である。すなわち、レンズアレイ２６としては従来、ロッドレンズアレイを配列して結合する構成のものであり、読み取り精度を上げるためには、ロッドレンズが屈折率を特定の関数で分布させた特殊な材料であることを要するため、ロッドレンズアレイよりなるイメージガイド部材のコストの低減が困難となる。
【０００７】
問題点の更に他の一つは、光源であるＬＥＤアレイ２５とレンズアレイ２６に関する組立の問題である。すなわち、従来は外装ケース８に対しＬＥＤアレイ２５、レンズアレイ２６および受光素子アレイ２４をそれぞれ別個に組み付けていた。そのため、これらの部品の寸法誤差および組み付け誤差により、原稿面の照明光のラインとレンズアレイのラインとのずれおよびレンズアレイのラインと受光素子アレイのずれを生ずる。これらのラインのずれにより、受光素子に入射する光の均一性が低下し、読み取り精度が低下する。又は、受光素子に入射する光の均一性を高く維持するには、ラインを精度よく整合させるため組立に時間と手間がかかり、製造コストの上昇を招く傾向がある。
【０００８】
本願は上記３つの問題点を解決することを課題とするものであり、本願の発明は、かかる課題を解決し、読み取り精度の高い画像読取装置、特に密着型画像読取装置を低い製造コストにおいて提供することを目的とする。
【０００９】
【課題を解決するための手段】
上記課題を解決するための第１の手段としては、原稿面をライン状に照明する照明手段、前記照射された原稿面からの反射光を結像する集光手段、前記結像された光を受光して光電変換するライン状に配列した複数の受光素子を有し、原稿面の画像データを受光素子への光入力により検知する画像読取装置において、前記照明手段は発光素子および該発光素子の発光を前記原稿面に案内する導光手段を備え、該導光手段は屈折率Ｎ１の母部材および該母部材の傾斜する側面に設けられ、原稿面に向けて上方に広がる複数のガイド溝と、その傾斜する側面の下端部においてこれら複数のガイド溝に連通する共通溝、並びにこれらガイド溝と共通溝に充填された屈折率Ｎ１より大なる屈折率を有する拡散用透光部材により構成され、前記共通溝内に発光素子が配置されることを特徴とする。
【００１０】
上記課題を解決するための第２の手段としては、前記第１の手段において、前記発光素子は光源基板に搭載され、その光源基板は前記発光素子が実装された状態で、前記拡散用透光部材の充填に先立って前記母部材に取り付けられることを特徴とする。
【００１１】
上記課題を解決するための第３の手段としては、前記第１の手段において、前記母部材は６の辺のうちで上方に２辺が凹形状をなす変則６角形の断面を有する角柱の形状をなし、前記角柱の長さ方向に沿って垂直に立ち上がる側面には垂直方向に平行なガイド溝が設けられ、前記垂直に立ち上がる側面の反対側で斜めに立ち上がる側面には下方から上方に向かって放射状に広がる複数のガイド溝が設けられていることを特徴とする。
【００１２】
上記課題を解決するための第４の手段としては、前記第１の手段において、屈折率Ｎ１である透光材よりなるスペーサが前記母部材の垂直に立ち上がる側面に接合された後、画像読取装置の外装ケースの内側の窪みに設けられたスペーサ位置決め用窪みに挿入接合されることを特徴とする。
【００１６】
【発明の実施の形態】
以下図面に基づいて本発明の好適な実施の形態の一つである実施例について説明する。図１は本実施例に係る密着型画像読取装置の構成を示す断面図でり、図２は図１のＡーＡ断面図であり、図３は図１に示す画像読取装置の要部である光路変換ユニットを示す斜視図である。１は屈折率ｎ１の母部材２および該母部材２に設けられた拡散用透光部材３および集光用透光部材４を有する光路変換ユニットである。拡散用透光部材３および集光用透光部材４は共に前記ｎ１に対し、ｎ２＞ｎ１なる関係を有する屈折率ｎ２の透光材よりなっている。集光用透光部材４の各柱状レンズの光入力端および光出力端にそれぞれ凸レンズ４ｂ１および４ｂ２が設けられている。１１は原稿１０を載置する透明板である。遮光材よりなる外装ケース１２はスぺーサ１３を介して光路変換ユニット１を保持するとともに、直接に透明板１１を支持する。後述する発光素子７および光源基板８は光路変換ユニット１に取付けられ、受光素子アレイ９は外装ケース１２の内側の底面において、集光素子４と対向する位置に配置されている。
【００１７】
母部材２は６の辺のうちで上方に２辺が凹形状をなす変則６角形の断面を有する角柱の形状をなし、前記角柱の長さ方向に沿って垂直に立ち上がるな側面２ｂには垂直方向に平行な複数のガイド溝５ｂが設けられ、該ガイド溝５ｂ内に集光用透光部材４が充填されている。前記垂直に立ち上がる側面２ｂの反対側で斜めに立ち上がる側面２ａには下方から上方に向かって放射状に広がる形で複数のガイド溝５ａが設けられ、側面２ａの下端中央およびその近傍には前記複数のガイド溝５ａと共通に連通する共通溝６が設けられている。共通溝６の内部にはＬＥＤからなる発光素子７が配置され、共通溝６およびガイド溝５ａには発光素子７を被うようにして、拡散用透光部材３が充填されている。母部材２の下面で側面２ａに隣接する部分には発光素子７を保持する光源基板８が取付けられている。光源基板８には発光素子７であるＬＥＤの図示しない電極と導通する図示しない配線が設けられている。光源基板８は発光素子７が実装された状態で、拡散用透光部材３の充填に先だって、母部材２に接着等により取付けられる。
【００１８】
スペーサ１３は屈折率が前記ｎ１である透光材よりなり、母部材の側面２ｂに接合された後、外装ケース１２の内壁に設けられたスペーサ位置決め用窪み１２ａに挿入され接合される。受光素子アレイ９は光電変換を行うフォトトランジスタ等からなるセンサー画素１５が複数配列された原稿読取受光素子１６と、保護膜１７と、これが実装された受光基板１８とからなる成る。受光基板１８は外装ケース１２の内側の底面に設けられた受光基板位置決め用窪み１２ｂａに挿入され、前記原稿読取受光素子１６のラインと、前記集光用透光部材４の配列ラインの位置が垂直方向に一致または略一致する位置おいて、接合固定される。母部材２の上側の端面でガイド溝５ａ、５ｂ以外の部分およびスペーサ１３の上端の露出した部分には塗料等よりなる遮光膜１４が設けられている。
【００１９】
本例の画像読取装置の動作につき説明する。図示しない光源駆動回路から光源基板８に設けられた前記配線を通じてＬＥＤからなる発光素子７の電極に駆動電圧を印加すると発光素子７は点灯し、ＬＥＤの種類に応じてＲ、Ｇ、Ｂのいずれか１色の光を発光する。図４は発光素子７であるＬＥＤの指向特性を示す図である。発光主面７ａの方向では強く、側面７ｂの方向に行くに従って弱くなる傾向がある。この傾向は図３の面に垂直な方向についても同様である。共通溝内６において、発光素子７からの発光の極く一部は拡散用透明部材３の表裏の界面を透過して空気中又は母部材２中に放射されるが、それ以外の光は直接に又は前記表裏の界面での反射を経て図３に示す指向特性にほぼ従ってガイド溝５ａに向かって発光が広がって行き、大部分の光がガイド溝５ａに入り込む。ガイド溝５ａに入り込んだ光は母部材２と拡散用透光部材３の界面をなすガイド溝５ａの側面および前記表裏の界面において、一部が透過し一部が反射する。
【００２０】
すなわち、拡散用透光部材３の側面及び裏側の界面においては相対的臨界角θ１は前記屈折率ｎ１とｎ２により決まり、θ１＝ｓｉｎ^ー1（ｎ１／ｎ２）となり、表の空気との界面においては固有の臨界角θ０はｎ２により決まり、θ０＝ｓｉｎ^ー1（１／ｎ２）となる。本例においては母部材２はアクリルであって、ｎ１＝１．４９、拡散用透光部材３はアクリル系樹脂であって、ｎ２＝１．５３であり、従って上記の関係から母部材２との界面の臨界角θ１はθ１＝ｓｉｎ^ー1（
１．４９／１．５３）＝７６．９°であり、空気との界面の臨界角θ０はθ０＝ｓｉｎ^ー1（１／１．５３）＝４０．８°である。ガイド溝５ａの拡散用透光部材３内に入り込んだ光の一部は前記側面の界面および表裏の界面のいずれをも経ることなく拡散用透光部材３の上端の界面から外部に射出される。これ以外の光は１回は前記界面に入射する。
【００２１】
このとき入射角（界面の法線に対する角度）θが界面の臨界角（θ１又はθ０）よりも小であるときは一部が通過し、一部が反射する。入射角θが前記臨界角と等しいか又は大であるときは光の全部が反射する。拡散用透光部材３の前記の表裏および側部の界面は図２に示すように入射光にほぼ沿った形となっているので前記界面に対する入射角９０度に近い場合が多く、大部分は当該界面の臨界角７６．９°又は７６．９°を越える角度で入射し前記界面を透過することなく１回又は複数回の反射の後に拡散用透光部材３の上端の界面から外部に射出される。拡散用透光部材３の各分岐部分は上端に近付くに従って幅が広くなり、上端部は互いに近接してライン状に配列されているので、発光素子７の発光は効率よく線状の光束に変換されて、拡散用透光部材３の上端面から外部に射出される。
【００２２】
拡散用透光部材３の各分岐に入射する光線の密度と出射する光線の密度の比率はその分岐の入射部の幅と出射部の幅の比に逆比例する関係にある。一方、発光素子７の指向特性により、各分岐の入射部における光線の密度は中央部の分岐が高く、両端部の分岐に行くに従って低下する傾向にある。従って、例えば、各分岐の入射部の幅を等しくとった場合に、出射部の幅については、中央部の分岐において広く、両端部に行くに従ってそれよりも狭くなるような適切な寸法とすれば、発光素子７の指向性が補正され、拡散用透光部材３の上端面から外部に射出される前記線状の光束の光線の密度は均一となり、明るさは均一となる。これとは逆に、各分岐の出射部の幅を等しくとり、入射部の寸法については中央部の分岐において狭く、両端部に行くに従ってそれよりも広くなるような適切な寸法とした場合も同様の効果が得られる。
【００２３】
このようにして１個の発光素子７を用いて、拡散用透光部材３の上端面から明るさの均一な線状の光束よりなる光を射出することができる。この線状の光束よりなる光は透明板１１の上に載置された原稿１０の面を照射し、原稿面上の読み取りライン上の拡散反射光を母部材２の垂直に立ち上がる側面２ｂにライン方向に配列された複数の柱状のレンズよりなる集光用透光部材４に入射する。ここで図３に示すように母部材２の側面２ｂに設けられた集光用透光部材４の配列ラインは母部材２の側面２ａに設けられた拡散用透光部材３の配列ラインと平行に設けられている。そして、拡散用透光部材３からの出射光の照射による原稿面上の照射ラインは本来、拡散用透光部材３の配列ラインに平行であり、又、原稿面上の読み取りラインは集光用透光部材４の配列ラインと平行である。よって、原稿面上の前記照射ラインと読み取りラインは平行となる。本例においては、照射ラインの幅は読み取りラインの幅より多少広くなっており、照射ラインの領域の中に読み取りラインの領域が入るようになっている。
【００２４】
照射ラインの領域においては、前述のように明るさの均一な照明がなされるので、原稿面上の読み取りラインの領域の拡散反射光は均一の条件で集光用透光部材４の配列ラインに入射する。すなわち、読み取りラインの領域内の原稿９の濃淡情報を均一の条件で光の強弱に変換して、前記凸レンズ４ｂ１を通って集光用透光部材４の配列ラインに入射する。
【００２５】
集光用透光部材４の配列ラインに入射した光は、集光用透光部材４を構成する各柱状レンズにおいて、一部はその側部の界面を経ることなく、入射と反対側に出射するが、大部分はすで説明したのと同様の原理により、その側部の界面における１回又は複数回の反射を経て入射と反対側に凸レンズ４ｂ２を経て出射する。
【００２６】
集光用透光部材４の配列ラインの各柱状レンズから凸レンズ４ｂ２を経て出射した光は前記の受光素子アレイ９の対応するセンサー画素１５に入射して結像する。本例においては集光用透光部材４と原稿面およびセンサ画素の間はある程度離れているが、凸レンズ４ｂ１、４ｂ２を設けることにより、入射端および出射端から離れたところで焦点を結び、原稿面の画像をぼけがないようにセンサー画素１５に結像することができる。前記焦点の位置は凸レンズ４ｂ１、４ｂ２の曲率を適宜選択することにより、適切な位置に合わせることができる。かかるレンズアレイにおいては、配列方向のレンズのピッチを小さくして行き、センサー画素１５の配列ピッチと同じか又は小とすることにより、結像の分解能をセンサー画素１５の配列ピッチで決まる所定のレベルにまで高めることができる。なお、レンズアレイのピッチを更に小さくし、１個のセンサー画素１５に対し複数の柱状レンズが対応するような構成とすると、分解能の限界そのものは変わらないが、センサー画素１５に対する柱状レンズの位置合わせに多少の誤差があっても、所定の分解能を確保することができるので有利である。本例においては、図２に示すように、集光用透光部材４の前記柱状レンズはその配列ライン方向におけるピッチが前記センサー画素１５の配列ピッチよりも小となるように構成されている。本例においては、前記柱状レンズは成形型等を用いて母部材２に形成された溝ｂに透光部材が充填されて形成されるので、配列ライン方向の幅およびピッチを必要に応じ小さくすることは容易にできる。
【００２７】
前記センサー画素１５における結像の明るさに対応して各センサー画素１５は電気信号出力する。これにより、前記原稿面上の読み取りラインの領域の反射光のもつ原稿１０の濃淡情報、即ち光の強弱を受光素子アレイ９における個々のセンサー画素１５が電気信号に変換し、シリアル又はパラレルに信号出力として読み取りラインごと図示しない信号出力端から出力する。そして、前記原稿１０とセンサー画素１５の列との相対位置をラインと垂直方向に移動させて、前記ラインごとのデータ送出を繰り返すことにより、２次元画像情報を時系列電気信号に変換する。かかる画像情報の電気信号への変換の原理は公知のものと同様である。
【００２８】
本例においては、上述のように、原稿１０の面における読み取りラインの領域内の原稿１０の濃淡情報を均一の条件で光の強弱に変換して、集光用透光部材４の配列ラインに入射し、入射した光が集光用透光部材４に導かれて、十分な分解能をもってセンサー画素に結像するので、画像情報が正確に電気信号に変換されるので、従来と同等又はそれ以上の画像データの再現性を備えることができる。
【００２９】
なお、図示は省略するが、原稿面と前記集光用透光部材４がかなり近接している場合は前記光入力端の凸レンズ４ｂ１を省略することができ、センサー画素と前記集光用透光部材４がかなり近接している場合は前記光出力端の凸レンズ４ｂ２を省略することができる。これは、集光用透光部材４の各柱状レンズそのものは光ファイバーと同様に集光作用はないが、ギャップがゼロに近い場合は光の拡散による画像情報のぼけ、分解能の低下が許容できる程度となるからである。
【００３０】
又、集光用透光部材４および拡散用透光部材３において、凸レンズ等の集光レンズを別途設けなくても、透光部材の屈折率を場所により変化させることにより、集光性を付与することができる。図５は透光部材内部におけるかかる集光作用を示す原理図である。２０は集光用透光部材４又は拡散用透光部材３に相当する透光部材であり、２０ａは屈折率ｎａの部分、２０ｂは屈折率ｎｂの部分であり、
ｎｂ＞ｎａの関係がある。部分２０ａと２０ｂの界面２０ｄは光の射出面２０ｃに対し中央部が突き出した形で傾斜している。界面２０ｄに対しその法線ＮＳに角度α１で入射した光線ｓ１は屈折して、この法線ＮＳに対し前記α１より大きい角度α２をなす光線ｓ２になり、部分２０ａを通過して外部に射出する。もし、透光部材２０が部分２０ｂのみのときは光線ｓ１は仮想線ｓ３の方向に進む。光線ｓ２は仮想線ｓ３に比べ内側に屈折していることがわかる。このように、界面２０ｄのレンズ効果により集光作用がなされる。上記のような部分的な屈折率の変化は添加剤の部分的な混入等により、実現することができる。
【００３１】
拡散用透光部材３の光の出射部においてこのような原理により厚み方向又は幅方向の光の拡散を防止し、原稿面上の必要な場所に効率よく、照度の高い前記照射ラインを照射することができる。
【００３２】
以上に述べたように、本実施例においては、原稿面照明用の光学手段である拡散用透光部材３と原稿面からの反射光を集光する光学手段である集光用透光部材４が共に共通の母部材２に形成され、一体として光路変換ユニット１が構成される。これにより、部品点数が減少し、部品の製造および組立の手間が低減されるとともに、拡散用透光部材３と集光用透光部材４の間の相対的な位置精度が光路変換ユニット１として確保されているので、組立の際に特別の調整をすることなく、集光用透光部材４の配列位置によって決まる原稿面における読み取りラインに対し、拡散用透光部材３の配列位置によって決まる原稿面における照明ラインを正しい位置関係で重ね合わせることができるので、原稿１０の濃淡情報を正しく反射光の強弱に変換して集光用透光部材４に入力することができ、画像読み取りの性能を高めることができる。
【００３３】
次に、原稿面に対する照明手段について言えば、すでに説明したように、１個の発光素子と拡散用透光部材３を組み合わせることにより、原稿面上に多数の発光素子を用いた従来の照明手段と同等又はそれ以上に均一な明るさの照明ラインを照射することができる。又、拡散用透光部材３は、母部材２の成型と同時に型等により形成されたガイド溝５ａに透光材を充填することにより、形成することができるので、光ファイバー等を用いた従来の光拡散手段に比し、製造コストの低減ができる。以上の理由により、本例の照明手段については従来よりも大幅にそのコストを低減することができる。
【００３４】
次に、原稿面からの反射光を集光する光学手段である集光用透光部材４についていえば、すでに説明したように、前記拡散用透光部材３と同様の方法により形成することができ、その構成要素である柱状レンズのピッチを小さくすることができるので、従来のロッドレンズアレイ等の集光光学手段に比して大幅なコストダウンができるとともに、画像読み取りの分解能を向上させる上で有利となる。
【００３５】
以下図面に基づいて本発明の好適な実施の形態の他の一つである実施例について説明する。図６は本実施例に係るフルカラー用の密着型画像読取装置における構成の一部を示す斜視図である。２は図１と同様の母部材であり、図２ａも同様の斜めに立ち上がる母部材の側面である。側面２ａには下方から上方に向かって放射状に広がる形で複数のガイド溝５ａが設けられ、側面２ａの下端中央およびその近傍には前記複数のガイド溝５ａと共通に連通する共通溝６が設けられている。共通溝６の内部にはＲ、Ｇ、ＢのＬＥＤが１個ずつ重なり合って発光素子７として配置され、共通溝６およびガイド溝５ａには発光素子７を被うようにして、拡散用透光部材３が充填されている。母部材２の下面で側面２ａに隣接する部分には発光素子７保持する光源基板８が取付けられている。光源基板８には発光素子７であるＲ、Ｇ、ＢのＬＥＤの図示しない電極の各々とそれぞれ導通する図示しない配線が設けられている。その他の構成については、図１に示した実施例と同様である。
【００３６】
本例の動作につき説明する。図示しない光源駆動回路から光源基板８に設けられた前記配線を通じて発光素子７のＲ、Ｇ、ＢのＬＥＤの電極に時分割で順次駆動電圧を印加するとＲ、Ｇ、ＢのＬＥＤは１色ごとに順次点灯する。そして原稿稿面上の同一の読み取りラインをカバーする照射ラインをすでに述べたのと同様の原理により、各色ごとに順次形成し、各色毎の拡散反射光を同様の原理によりセンサー画素に入射、結像して前記原稿面上の読み取りラインの領域の反射光のもつ原稿１０の各色別の濃淡情報、即ち各色別の光の強弱を受光素子アレイ９における個々のセンサー画素１５が色別に時分割的に順次電気信号に変換し、シリアル又はパラレルに信号出力として読み取りラインごと図示しない信号出力端から出力する。
【００３７】
そして、その読みとりラインにおけるＲ、Ｇ，Ｂすべての出力が終了した後、前記原稿１０とセンサー画素１５の列との相対位置をラインと垂直方向に移動させて、前記ラインごとのデータ送出を繰り返すことにより、２次元のフルカラー画像情報を時系列電気信号に変換する。かかる画像情報の電気信号への変換の原理は公知のものと同様である。本例においては、ＬＥＤの数は３個で、フルカラー用の密着型画像読取装置としては、ＬＥＤの数を低減させることができる。その他、図１に示した実施例と同様の長所を有する。
【００３８】
以上に述べてきた実施例においては、共通の母部材２にガイド溝５ａ、５ｂを設けてこれらに透光部材を充填し、前記光路変換ユニット１が構成されていたが、本発明はこれに限らず、図７に示すように別々の母部材２にそれぞれガイド溝５ａ、５ｂを形成し、照明手段部１ａと集光手段部１ｂこれらに透光部材を充填して照明手段部１ａと集光手段部１ｂを別々に構成した後に、該照明手段部１ａと集光手段部１ｂをを接合して光路変換ユニット１を構成することもできる。更に、照明手段部１ａを単独で原稿照明手段として別個の画像読取装置に使用しても、コスト低減の効果が得られる。集光手段部１ｂについても同様である。
【００３９】
本発明は更に図８に示すように光路変換ユニット１の集光用透光部材４の下側において共通の母部材２に位置決め用のスリット部２ｄを設け、該スリット部２ｄに受光素子アレイ基板１８を収納、位置決めする構成のものを適用することもできる。本例においては、同一母材に、拡散用透光部材３、集光用透光部材４、及びセンサー画素１５を搭載する受光素子アレイ基板１８が設けられるので、これらの位置関係を精度よく設定することができるとともに、図示しないケースへの組み付けも調整なしにできるので容易となる。又、本例においては、センサー画素１５と集光用透光部材４とが近接しているため、前記光出力端の凸レンズ４ｂ２を省略することができる。
【００４０】
【発明の効果】
以上説明したように本発明によれば、読み取り性能に優れた画像読取装置を低い製造コストにおいて提供することができる。
【図面の簡単な説明】
【図１】本発明の実施の形態の一つである画像読取装置の構成を示す断面図である。
【図２】図１のＡーＡ断面図である。
【図３】図１に示す画像読取装置の要部の構成を示す斜視図である。
【図４】図１に示す画像読取装置の光源の発光素子の発光の指向性を示す図である。
【図５】透光部材内における集光作用を示す原理図である。
【図６】本発明の実施の形態の一つである画像読取装置の要部の構成を示す斜視図である。
【図７】本発明の実施の形態の一つである画像読取装置の要部の構成を示す斜視図である。
【図８】本発明の実施の形態の一つである画像読取装置の要部の構成を示す斜視図である。
【図９】従来の画像読取装置の構成を示す断面図である。
【符号の説明】
１光路変換ユニット
２母部材
３拡散用透光部材
４集光用透光部材
４ｂ凸レンズ
５ガイド溝
７発光素子
１０原稿
１５センサー画素
１６原稿読取受光素子[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image reading apparatus that reads an image of a document as an input device such as a computer, a facsimile machine, and a copying machine.
[0002]
[Prior art]
An image reading apparatus is excellent in operability and versatility as an image input apparatus, and has been widely used in recent years in fields such as OA equipment and information equipment. In particular, in recent years, the demand for household facsimile machines has increased, and a compact and easy-to-use image reading apparatus for use therein has been demanded. Therefore, a contact type using a light emitting diode (hereinafter referred to as “LED”) array as a light source. Image reading apparatuses are becoming widespread. FIG. 8 is a sectional view of such a conventional contact-type image reading apparatus, and its outline will be described.
[0003]
As shown in FIG. 9, the contact-type image reading apparatus has a light receiving element array 24 including a document reading light receiving element 21 in which a plurality of sensor pixels that perform photoelectric conversion are arranged, a protective film 22, and a substrate 23 on which the protective film 22 is mounted. An LED array 25 that is a linear light source that irradiates the document, a lens array 26 that forms an image of the document 29 on the light receiving element array 24 that is a light receiving unit, a transparent plate 27 on which the document 29 is placed, It is comprised from the exterior case 28 which supports these members.
[0004]
In the operation of the contact type image reading apparatus, the LED array 25 irradiates the document surface, diffuse reflected light on the document surface reading line is imaged on the light receiving element array by the lens array 26, and the reflected light has The density information of the document 29, that is, the intensity of light, is converted into an electrical signal by each sensor pixel in the light receiving element array 24 and sent out as a serial or parallel signal output for each reading line. Then, the two-dimensional image information is converted into a time-series electric signal by moving the relative position between the document 29 and the sensor pixel row in the direction perpendicular to the line and repeating the data transmission for each line.
[0005]
However, the above-mentioned contact type image reading apparatus has the following problems. One of the problems is related to the light source. That is, if the number of LEDs in the LED array 25 is increased and the illuminance of the original surface to be illuminated is made substantially uniform by increasing the number of LEDs in the LED array 25 in order to increase the reading accuracy, the number of LEDs used is large. Therefore, the parts cost is high, and it is difficult to reduce the cost.
[0006]
Another problem is related to the lens array. In other words, the lens array 26 has a conventional structure in which rod lens arrays are arrayed and coupled. In order to increase the reading accuracy, the rod lens is a special material in which the refractive index is distributed with a specific function. Therefore, it is difficult to reduce the cost of the image guide member made of the rod lens array.
[0007]
Still another problem is an assembly problem related to the LED array 25 and the lens array 26 which are light sources. That is, conventionally, the LED array 25, the lens array 26, and the light receiving element array 24 are separately assembled to the exterior case 8. Therefore, due to the dimensional error and assembly error of these parts, a deviation between the illumination light line on the document surface and the lens array line and a deviation between the lens array line and the light receiving element array occur. Due to the deviation of these lines, the uniformity of the light incident on the light receiving element is lowered, and the reading accuracy is lowered. Alternatively, in order to maintain high uniformity of the light incident on the light receiving element, it takes time and labor to assemble the lines with high accuracy, which tends to increase manufacturing costs.
[0008]
The present application aims to solve the above three problems, and the invention of the present application solves such problems and provides an image reading apparatus with high reading accuracy, particularly a contact image reading apparatus, at a low manufacturing cost. The purpose is to do.
[0009]
[Means for Solving the Problems]
As a first means for solving the above problems, an illuminating means for illuminating the original surface in a line shape, a condensing means for forming an image of reflected light from the irradiated original surface, and the imaged light In an image reading apparatus having a plurality of light receiving elements arranged in a line for receiving and photoelectrically converting light, and detecting image data of a document surface by optical input to the light receiving element, the illumination means includes the light emitting element and the light emitting element. Light guide means for guiding light emission to the document surface is provided, and the light guide means is a base member having a refractive index N1. And a plurality of guide grooves provided on the inclined side surface of the base member and extending upward toward the document surface, a common groove communicating with the plurality of guide grooves at a lower end portion of the inclined side surface, and the guide grooves A light transmissive element for diffusion having a refractive index greater than the refractive index N1 filled in the common groove is disposed, and a light emitting element is disposed in the common groove. It is characterized by that.
[0010]
As a second means for solving the above problem, in the first means, The light emitting element is mounted on a light source substrate, and the light source substrate is attached to the base member prior to filling of the light transmissive member for diffusion in a state where the light emitting element is mounted. It is characterized by that.
[0011]
As a third means for solving the above-mentioned problem, 1 In the means of The base member has a prismatic shape having an irregular hexagonal cross section in which two of the six sides are concave upward, and is perpendicular to a side surface that rises vertically along the lengthwise direction of the prism. Parallel guide grooves are provided, and a plurality of guide grooves that radiate from the lower side to the upper side are provided on the side surface that rises obliquely on the opposite side of the side surface that rises vertically. It is characterized by that.
[0012]
As a fourth means for solving the above-mentioned problems, 1 In the means of A spacer made of a light-transmitting material having a refractive index N1 is joined to a side surface that rises vertically of the base member, and is then inserted and joined to a spacer positioning recess provided in a recess inside the exterior case of the image reading apparatus. It is characterized by that.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example which is one of the preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a configuration of a contact image reading apparatus according to the present embodiment, FIG. 2 is a cross-sectional view taken along line AA of FIG. 1, and FIG. 3 is a main part of the image reading apparatus shown in FIG. It is a perspective view which shows a certain optical path conversion unit. Reference numeral 1 denotes an optical path conversion unit having a base member 2 having a refractive index n1, a diffusing translucent member 3 and a concentrating translucent member 4 provided on the base member 2. Both the light transmissive member 3 for diffusion and the light transmissive member 4 for light collection are made of a light transmissive material having a refractive index n2 having a relationship of n2> n1 with respect to the n1. Convex lenses 4b1 and 4b2 are provided at the light input end and the light output end of each columnar lens of the condensing translucent member 4, respectively. Reference numeral 11 denotes a transparent plate on which the document 10 is placed. An outer case 12 made of a light shielding material holds the optical path conversion unit 1 via a spacer 13 and directly supports the transparent plate 11. A light emitting element 7 and a light source substrate 8 which will be described later are attached to the optical path conversion unit 1, and the light receiving element array 9 is disposed at a position facing the light collecting element 4 on the bottom surface inside the exterior case 12.
[0017]
The base member 2 has the shape of a prism having an irregular hexagonal cross section in which two of the six sides are concave upward, and is perpendicular to the side surface 2b that does not rise vertically along the length direction of the prism. A plurality of guide grooves 5b parallel to the direction are provided, and the condensing translucent member 4 is filled in the guide grooves 5b. A plurality of guide grooves 5a are provided on the side surface 2a that rises obliquely on the opposite side of the side surface 2b that rises vertically, and radially extends from below to above. A common groove 6 communicating with the guide groove 5a is provided. A light emitting element 7 made of LED is disposed inside the common groove 6, and the light transmitting element 7 is filled in the common groove 6 and the guide groove 5 a so as to cover the light emitting element 7. A light source substrate 8 that holds the light emitting element 7 is attached to a portion of the lower surface of the base member 2 adjacent to the side surface 2a. The light source substrate 8 is provided with a wiring (not shown) that is electrically connected to an electrode (not shown) of the LED that is the light emitting element 7. The light source substrate 8 is attached to the base member 2 by adhesion or the like prior to filling of the diffusing translucent member 3 with the light emitting element 7 mounted thereon.
[0018]
The spacer 13 is made of a translucent material having a refractive index of n1, and after being joined to the side surface 2b of the base member, it is inserted into and joined to the spacer positioning recess 12a provided on the inner wall of the exterior case 12. The light receiving element array 9 includes a document reading light receiving element 16 in which a plurality of sensor pixels 15 including phototransistors or the like that perform photoelectric conversion are arranged, a protective film 17, and a light receiving substrate 18 on which the protective film 17 is mounted. The light receiving substrate 18 is inserted into a light receiving substrate positioning recess 12ba provided on the inner bottom surface of the outer case 12, and the positions of the original reading light receiving element 16 line and the arrangement line of the light collecting light transmitting member 4 are perpendicular to each other. Joining and fixing are performed at a position that matches or substantially matches the direction. A light shielding film 14 made of a paint or the like is provided on the upper end surface of the base member 2 at portions other than the guide grooves 5a and 5b and the exposed upper end of the spacer 13.
[0019]
The operation of the image reading apparatus of this example will be described. When a driving voltage is applied from the light source driving circuit (not shown) to the electrode of the light emitting element 7 made of LED through the wiring provided on the light source substrate 8, the light emitting element 7 is turned on, and any of R, G, and B is selected depending on the type of LED. Or emit light of one color. FIG. 4 is a diagram showing the directivity characteristics of the LED which is the light emitting element 7. It tends to be strong in the direction of the light emitting main surface 7a and weaken as it goes in the direction of the side surface 7b. This tendency is the same in the direction perpendicular to the plane of FIG. In the common groove 6, only a part of the light emitted from the light emitting element 7 passes through the front and back interfaces of the diffusing transparent member 3 and is emitted into the air or the mother member 2. In addition, light emission spreads toward the guide groove 5a almost according to the directivity shown in FIG. 3 through reflection at the front and back interfaces, and most of the light enters the guide groove 5a. The light that has entered the guide groove 5a is partially transmitted and partially reflected at the side surface of the guide groove 5a that forms the interface between the base member 2 and the diffusing light-transmitting member 3 and the front and back interfaces.
[0020]
That is, the relative critical angle θ1 is determined by the refractive indices n1 and n2 at the side and back side interfaces of the diffusing translucent member 3, and θ1 = sin. ^{ー 1} (N1 / n2), and the intrinsic critical angle θ0 is determined by n2 at the interface with air in the table, and θ0 = sin ^{ー 1} (1 / n2). In this example, the base member 2 is acrylic, n1 = 1.49, the diffusing translucent member 3 is an acrylic resin, and n2 = 1.53. The critical angle θ1 of the interface is θ1 = sin ^{ー 1} (
1.49 / 1.53) = 76.9 °, and the critical angle θ0 at the interface with air is θ0 = sin. ^{ー 1} (1 / 1.53) = 40.8 °. A part of the light that has entered the diffusing translucent member 3 in the guide groove 5a is emitted to the outside from the upper end interface of the diffusing translucent member 3 without passing through either the side interface or the front and back interfaces. . Other light enters the interface once.
[0021]
At this time, when the incident angle (angle with respect to the normal of the interface) θ is smaller than the critical angle (θ1 or θ0) of the interface, a part passes and a part is reflected. When the incident angle θ is equal to or greater than the critical angle, all of the light is reflected. As shown in FIG. 2, the front and back and side interfaces of the diffusing translucent member 3 are substantially along the incident light as shown in FIG. 2, and are often close to an incident angle of 90 degrees with respect to the interface. The incident light is incident at an angle exceeding the critical angle 76.9 ° or 76.9 ° of the interface, and after being reflected one or more times without being transmitted through the interface, exits from the interface at the upper end of the diffusing translucent member 3 to the outside. Is done. Each branch portion of the diffusing translucent member 3 becomes wider as it approaches the upper end, and the upper end portions are arranged in a line close to each other, so that the light emitted from the light emitting element 7 is efficiently converted into a linear light beam. Then, the light is emitted from the upper end surface of the diffusing translucent member 3 to the outside.
[0022]
The ratio of the density of light incident on each branch of the diffusing translucent member 3 and the density of light emitted therefrom is inversely proportional to the ratio between the width of the incident part and the width of the output part of the branch. On the other hand, due to the directivity characteristics of the light-emitting element 7, the density of light rays at the incident part of each branch tends to decrease as the branch at both ends is high, with the branch at the center being high. Therefore, for example, when the width of the incident part of each branch is made equal, the width of the output part should be an appropriate size that is wide at the branch of the central part and narrower as it goes to both ends. The directivity of the light emitting element 7 is corrected, the density of light rays of the linear light beam emitted from the upper end surface of the diffusing translucent member 3 to the outside becomes uniform, and the brightness becomes uniform. On the contrary, the width of the exit part of each branch is made equal, and the dimensions of the incident part are the same in the case of an appropriate dimension that is narrow at the center branch and becomes wider as it goes to both ends. The effect is obtained.
[0023]
In this way, it is possible to emit light composed of a linear light flux with uniform brightness from the upper end surface of the diffusing translucent member 3 by using one light emitting element 7. The light composed of the linear light beam irradiates the surface of the document 10 placed on the transparent plate 11, and diffused reflected light on the reading line on the document surface is lined on the side surface 2 b rising vertically of the base member 2. The light enters the condensing translucent member 4 made up of a plurality of columnar lenses arranged in the direction. Here, as shown in FIG. 3, the arrangement line of the concentrating translucent member 4 provided on the side surface 2 b of the base member 2 is parallel to the arrangement line of the diffusing translucent member 3 provided on the side surface 2 a of the base member 2. Is provided. The irradiation line on the original surface due to the irradiation of the light emitted from the diffusing translucent member 3 is essentially parallel to the array line of the diffusing translucent member 3 and the reading line on the original surface is for condensing. It is parallel to the array line of the translucent members 4. Therefore, the irradiation line and the reading line on the document surface are parallel. In this example, the width of the irradiation line is slightly wider than the width of the reading line, and the reading line region is included in the irradiation line region.
[0024]
Since the illumination line area is illuminated with uniform brightness as described above, the diffuse reflected light in the reading line area on the document surface is applied to the array line of the concentrating translucent member 4 under uniform conditions. Incident. That is, the density information of the document 9 in the reading line area is converted into light intensity under uniform conditions, and enters the array line of the condensing translucent member 4 through the convex lens 4b1.
[0025]
Light incident on the arrangement line of the concentrating translucent member 4 is partially emitted from the columnar lenses constituting the concentrating translucent member 4 to the side opposite to the incident side without passing through the side interface. However, most of the light is emitted through the convex lens 4b2 on the side opposite to the incident side after one or a plurality of reflections at the interface of the side portion based on the same principle as described above.
[0026]
Light emitted from the columnar lenses of the array line of the condensing light-transmitting member 4 through the convex lens 4b2 enters the corresponding sensor pixel 15 of the light receiving element array 9 and forms an image. In this example, the concentrating translucent member 4 is separated from the document surface and the sensor pixel to some extent, but by providing the convex lenses 4b1 and 4b2, the focal point is formed away from the entrance end and the exit end, and the document surface Can be formed on the sensor pixel 15 so as not to be blurred. The position of the focal point can be adjusted to an appropriate position by appropriately selecting the curvature of the convex lenses 4b1 and 4b2. In such a lens array, the pitch of the lenses in the arrangement direction is reduced to be the same as or smaller than the arrangement pitch of the sensor pixels 15 so that the imaging resolution is a predetermined level determined by the arrangement pitch of the sensor pixels 15. Can be increased to. If the pitch of the lens array is further reduced and a plurality of columnar lenses correspond to one sensor pixel 15, the resolution limit itself does not change, but the alignment of the columnar lens with respect to the sensor pixel 15 is not changed. Even if there is a slight error, it is advantageous because a predetermined resolution can be ensured. In this example, as shown in FIG. 2, the columnar lenses of the condensing translucent member 4 are configured such that the pitch in the arrangement line direction is smaller than the arrangement pitch of the sensor pixels 15. In this example, the columnar lens is formed by filling the groove b formed in the base member 2 with a translucent member using a mold or the like, so that the width and pitch in the array line direction are reduced as necessary. It can be done easily.
[0027]
Each sensor pixel 15 outputs an electrical signal corresponding to the brightness of image formation in the sensor pixel 15. As a result, the individual sensor pixels 15 in the light receiving element array 9 convert the density information of the original 10 of the reflected light in the read line area on the original surface, that is, the intensity of the light, into electrical signals, and the signals are serially or in parallel. The output is output from the signal output terminal (not shown) together with the reading line. Then, the relative position between the original 10 and the column of sensor pixels 15 is moved in the direction perpendicular to the line, and the data transmission for each line is repeated, thereby converting the two-dimensional image information into a time-series electric signal. The principle of conversion of such image information into an electrical signal is the same as that known in the art.
[0028]
In this example, as described above, the density information of the document 10 in the area of the reading line on the surface of the document 10 is converted into light intensity under uniform conditions, and the light is converted into an array line of the light-transmissive member 4 for condensing light. The incident light is guided to the condensing light-transmitting member 4 and forms an image on the sensor pixel with sufficient resolution, so that the image information is accurately converted into an electric signal. The reproducibility of the image data can be provided.
[0029]
Although not shown, when the original surface and the condensing translucent member 4 are quite close to each other, the convex lens 4b1 at the light input end can be omitted, and the sensor pixel and the condensing translucent light can be omitted. When the member 4 is quite close, the convex lens 4b2 at the light output end can be omitted. This is because each of the columnar lenses of the condensing translucent member 4 does not have a condensing function as in the case of the optical fiber, but if the gap is close to zero, image information blur due to light diffusion and a reduction in resolution can be tolerated. Because it becomes.
[0030]
Further, in the light-transmitting light-transmitting member 4 and the light-transmitting light-transmitting member 3, the light-reflecting property is imparted by changing the refractive index of the light-transmitting member depending on the location without providing a condensing lens such as a convex lens. can do. FIG. 5 is a principle view showing the light collecting action inside the translucent member. 20 is a light transmissive member corresponding to the light transmissive member 4 for condensing or the light transmissive member 3 for diffusion, 20a is a portion having a refractive index na, 20b is a portion having a refractive index nb,
There is a relationship of nb> na. The interface 20d between the portions 20a and 20b is inclined with the central portion protruding from the light exit surface 20c. The light ray s1 incident on the normal NS with respect to the interface 20d at an angle α1 is refracted to become a light ray s2 having an angle α2 larger than α1 with respect to the normal NS, and passes through the portion 20a and exits to the outside. . If the translucent member 20 is only the portion 20b, the light ray s1 travels in the direction of the virtual line s3. It can be seen that the light ray s2 is refracted inward compared to the virtual line s3. In this way, the light condensing action is performed by the lens effect of the interface 20d. The partial change in refractive index as described above can be realized by partial mixing of the additive.
[0031]
The light emitting portion of the diffusing translucent member 3 prevents the diffusion of light in the thickness direction or the width direction by such a principle, and efficiently irradiates the irradiation line with high illuminance to a required place on the document surface. be able to.
[0032]
As described above, in this embodiment, the diffusing translucent member 3 which is an optical means for illuminating the original surface and the condensing translucent member 4 which is an optical means for condensing the reflected light from the original surface. Are formed on a common base member 2, and the optical path conversion unit 1 is formed as a unit. As a result, the number of parts is reduced, the labor of manufacturing and assembling parts is reduced, and the relative positional accuracy between the diffusing translucent member 3 and the concentrating translucent member 4 is the optical path conversion unit 1. Since it is secured, the original determined by the arrangement position of the diffusing translucent member 3 with respect to the reading line on the original surface determined by the arrangement position of the concentrating translucent member 4 without special adjustment at the time of assembly. Since the illumination lines on the surface can be overlapped with the correct positional relationship, the shading information of the document 10 can be correctly converted into the intensity of the reflected light and input to the condensing translucent member 4, and the image reading performance can be improved. Can be increased.
[0033]
Next, as to the illumination means for the original surface, as described above, the conventional illumination means using a large number of light emitting elements on the original surface by combining one light emitting element and the diffusing translucent member 3. It is possible to irradiate an illumination line with uniform brightness equal to or higher than. Further, since the light transmissive member 3 for diffusion can be formed by filling the guide groove 5a formed by a mold or the like simultaneously with the molding of the base member 2, a light transmissive member 3 can be formed. Compared with the light diffusion means, the manufacturing cost can be reduced. For the above reasons, the cost of the illumination means of this example can be greatly reduced as compared with the conventional case.
[0034]
Next, as for the condensing translucent member 4 which is an optical means for condensing the reflected light from the document surface, it can be formed by the same method as the diffusing translucent member 3 as described above. In addition, since the pitch of the columnar lenses, which are the constituent elements, can be reduced, the cost can be greatly reduced as compared with a conventional condensing optical means such as a rod lens array, and the resolution of image reading can be improved. Is advantageous.
[0035]
Hereinafter, an example which is another preferred embodiment of the present invention will be described with reference to the drawings. FIG. 6 is a perspective view showing a part of the configuration of the full-color contact image reading apparatus according to the present embodiment. 2 is a base member similar to FIG. 1, and FIG. 2a is also a side surface of the base member rising obliquely. A plurality of guide grooves 5a are provided on the side surface 2a so as to radiate from the bottom to the top, and a common groove 6 that communicates with the plurality of guide grooves 5a is provided at the bottom center of the side surface 2a and in the vicinity thereof. It has been. The R, G, and B LEDs overlap each other as the light emitting element 7 inside the common groove 6, and the common groove 6 and the guide groove 5 a cover the light emitting element 7 to transmit the light for diffusion. The member 3 is filled. A light source substrate 8 that holds the light emitting element 7 is attached to a portion of the lower surface of the base member 2 adjacent to the side surface 2a. The light source substrate 8 is provided with a wiring (not shown) that is electrically connected to each of the electrodes (not shown) of the R, G, and B LEDs that are the light emitting elements 7. Other configurations are the same as those of the embodiment shown in FIG.
[0036]
The operation of this example will be described. When a drive voltage is sequentially applied to the electrodes of the R, G, and B LEDs of the light emitting element 7 through the wiring provided on the light source substrate 8 from a light source driving circuit (not shown), the R, G, and B LEDs are set for each color. Light up sequentially. Then, irradiation lines that cover the same reading line on the manuscript are formed sequentially for each color according to the same principle as described above, and diffuse reflected light for each color is incident on the sensor pixel and connected according to the same principle. The individual sensor pixels 15 in the light receiving element array 9 are time-divisionally divided according to the color by the color information of each color of the document 10 that is reflected by the reflected light in the reading line area on the document surface, that is, the intensity of light for each color. Are sequentially converted into electrical signals, and output from the signal output terminal (not shown) together with the read lines as serial or parallel signal outputs.
[0037]
Then, after output of all R, G, and B in the reading line is completed, the relative position between the original 10 and the column of sensor pixels 15 is moved in the direction perpendicular to the line, and data transmission for each line is repeated. Thus, the two-dimensional full-color image information is converted into a time series electric signal. The principle of conversion of such image information into an electrical signal is the same as that known in the art. In this example, the number of LEDs is three, and the number of LEDs can be reduced as a full-color contact image reading apparatus. In addition, it has the same advantages as the embodiment shown in FIG.
[0038]
In the embodiment described above, the guide groove 5a, 5b is provided in the common base member 2 and filled with the light transmitting member, and the optical path conversion unit 1 is configured. Not limited to this, as shown in FIG. 7, the guide grooves 5a and 5b are formed in the separate base members 2, respectively, and the illumination means 1a and the light collection means 1b are filled with a translucent member to collect the illumination means 1a and the collection means. It is also possible to configure the optical path conversion unit 1 by joining the illuminating unit 1a and the condensing unit 1b after configuring the optical unit 1b separately. Further, even if the illuminating unit 1a is used alone as a document illuminating unit in a separate image reading apparatus, an effect of cost reduction can be obtained. The same applies to the condensing unit 1b.
[0039]
In the present invention, as shown in FIG. 8, a positioning slit portion 2d is provided in the common base member 2 below the condensing light-transmitting member 4 of the optical path conversion unit 1, and a light receiving element array substrate is provided in the slit portion 2d. A configuration for storing and positioning 18 can also be applied. In this example, since the light-transmitting element array substrate 18 on which the light-transmitting diffusion member 3, the light-transmitting light-transmitting member 4, and the sensor pixel 15 are mounted on the same base material, these positional relationships are set with high accuracy. In addition, it is easy to assemble to a case (not shown) without adjustment. In this example, since the sensor pixel 15 and the condensing translucent member 4 are close to each other, the convex lens 4b2 at the light output end can be omitted.
[0040]
【The invention's effect】
As described above, according to the present invention, an image reading apparatus having excellent reading performance can be provided at a low manufacturing cost.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a configuration of an image reading apparatus which is one embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the line AA of FIG.
3 is a perspective view showing a configuration of a main part of the image reading apparatus shown in FIG. 1. FIG.
4 is a diagram showing the directivity of light emission of a light emitting element of a light source of the image reading apparatus shown in FIG.
FIG. 5 is a principle view showing a light condensing action in a translucent member.
FIG. 6 is a perspective view illustrating a configuration of a main part of an image reading apparatus that is one embodiment of the present invention.
FIG. 7 is a perspective view illustrating a configuration of a main part of an image reading apparatus which is one embodiment of the present invention.
FIG. 8 is a perspective view illustrating a configuration of a main part of an image reading apparatus which is one embodiment of the present invention.
FIG. 9 is a cross-sectional view illustrating a configuration of a conventional image reading apparatus.
[Explanation of symbols]
1 Optical path conversion unit
2 Base material
3 Translucent translucent member
4 Translucent member for condensing
4b Convex lens
5 Guide groove
7 Light emitting elements
10 Manuscript
15 Sensor pixels
16 Document reading light receiving element

Claims

Illumination means for illuminating the original surface in a line, condensing means for forming an image of reflected light from the irradiated original surface, and a plurality of light receiving elements arranged in a line for receiving and photoelectrically converting the imaged light In the image reading apparatus having an element and detecting image data of the document surface by light input to the light receiving element, the illuminating unit includes a light emitting element and a light guiding unit for guiding light emission of the light emitting element to the document surface, The light guide means is provided on the base member having the refractive index N1 and the inclined side surfaces of the base member, and has a plurality of guide grooves extending upward toward the document surface, and the plurality of guide grooves at the lower end portion of the inclined side surfaces. And a diffusion light-transmitting member having a refractive index higher than the refractive index N1 filled in the guide groove and the common groove, and a light emitting element is disposed in the common groove. Image reading Apparatus.

The light emitting device is mounted on a light source substrate, and the light source substrate is attached to the base member prior to filling of the light transmissive member for diffusion in a state where the light emitting device is mounted. The image reading apparatus described .

The base member has a prismatic shape having an irregular hexagonal cross section in which two of the six sides are concave upward, and is perpendicular to a side surface that rises vertically along the lengthwise direction of the prism. The parallel guide groove is provided, and a plurality of guide grooves that radiate from the lower side to the upper side are provided on the side surface that rises obliquely on the opposite side of the side surface that rises vertically. The image reading apparatus described .

A spacer made of a light-transmitting material having a refractive index N1 is bonded to a side surface of the base member that rises vertically, and then inserted and bonded to a spacer positioning recess provided in a recess inside the exterior case of the image reading apparatus. The image reading apparatus according to claim 1 .