JP3594886B2 - Article provided with waveguide hologram type forgery prevention seal - Google Patents

Description

【数２】

としたとき、
【数３】

を満たすことである。
但し、
【数４】

はクロネッカーのデルタである。
【００４６】
一般に、振幅マスクと異なり、位相マスクを作製するのは費用がかかるので、２５００００種類の位相マスクをすべて試すという作業には膨大な費用と時間を要する。従って、導波路ホログラムの作製技術を有する機関であっても、その位相変調パターンを知らない限り、複製することは困難であり、上述した基準（６）を満たすことがわかる。
【００４７】
この第２及び第３の実施の形態の偽造防止シールにおいては、必要に応じて各層の外部光結合用ホログラムのグレーティングの周期を層によって異なる構成を付加することで、安全性のレベルをさらに上げることが可能である。
偽造が疑われる時には、通常は使わない層と波長と位相パターンを用いる。
この構成を第２の実施の形態の偽造防止シールに付加する場合には、入力部の位置は互いに重ならないように配置する必要があるが、この構成を第３の実施の形態の偽造防止シールに付加する場合には、入力部は互いに重なりがあっても良い。
【００４８】
入力部が２ヵ所あることで、上記と同様の大きさを仮定すると、２５００００種類の位相パターンがあり得る。したがって、両者で２５００００×２５００００種類、即ち６２５億種類の位相パターンがあり得る。これを解読し偽造することは、実効上“不可能”である。また、第二層の波長や、第二層の存在そのものを秘密にしておくこともセキュリティレベルを上げる為には有効である。
【００４９】
上述した基準（４）は、剥がし難い接着剤、例えば、２液混合タイプのエポキシ系接着剤等を用いることで満足することができる。より難しい基準は基準（５）であり、万が一剥がされた場合に、剥がされたという履歴が確認できる機能を有することである。この構成が次に説明する導波路ホログラム型偽造防止シールを備えた物品である。
【００５０】
［第４の実施の形態］
図４は、本発明の第４の実施の形態に係る導波路ホログラム型偽造防止シールを備えた物品を示す部分断面図であり、図において、符号７１は被接着物、７２は導波路ホログラム型偽造防止シール、７３は透明カバーシール（透明シール）、７４は被接着物７１と透明カバーシール７３との接着部、７５は偽造防止シール７２と透明カバーシール７３との接着部、７６は偽造防止シール７２と被接着物７１との接着部である。
【００５１】
被接着物７１は、具体的には、パスポート用紙、各種免許証、会員証そのものである。
偽造防止シール７２は、クラッド８１、コア８２及びクラッド８３により構成されている。ここでは、偽造防止シール７２のコア８２は１層しか示していないが、複数あってもよい。
【００５２】
ここで、被接着物７１と透明カバーシール７３との間の接着強度をＡｓｂ、被接着物７１と偽造防止シール７２との間の接着強度をＡｗｂ、透明カバーシール７３と偽造防止シール７２との接着強度をＡｓｗ、コア８２とクラッド８１、８３との間の接着強度をＡｃｃとすると、
Ａｓｂ＞＞Ａｃｃ ……（２−１）
Ａｗｂ＞＞Ａｃｃ ……（２−２）
Ａｓｗ＞＞Ａｃｃ ……（２−３）
を満たしている。
【００５３】
すなわち、被接着物７１と偽造防止シール７２との間の接着強度、偽造防止シール７２と透明カバーシール７３との間の接着強度、及び透明カバーシール７３と被接着物７１との間の接着強度は、光導波路のコア８２とクラッド８１、８３との間の接着強度より大となっている。
以上により、透明カバーシール７３を剥がそうと試みると、この透明カバーシール７３が剥がれる前に、コア８２とクラッド８１、８３との間の接着部分で剥がれることになり、二度と光を導波することはない。したがって、上述した基準（５）を満たすことができる。
【００５４】
［第５の実施の形態］
図５は、本発明の第５の実施の形態に係る導波路ホログラム型偽造防止シールを示す図で、（ａ）は上面図、（ｂ）は側面図であり、図において、符号９１は偽造防止シールの入力部、９２は同出力部である。この偽造防止シールは、ポリカーボネートシート９３上に、クラッド９４、コア９５、クラッド９６が順次積層され、このポリカーボネートシート９３の裏面が接着面とされている。また、符号９７は半導体レーザ、９８は凸レンズ、９９は導波光、１００は回折光、１０１はボイスコイル等の振動手段により半導体レーザ９７に与えられた振動である。
【００５５】
半導体レーザ９７としては、光磁気ディスクの光源に用いられている６８０ｎｍの赤色半導体レーザが好適に用いられる。
この偽造防止シールは、厚み２２１μｍ×幅１ｍｍ×長さ３ｃｍの細長いシートである。このシートの長手方向の一方の端部に１ｍｍ×１ｍｍの大きさの一様グレーティングからなる入力部９１が、もう一方の端部に１ｍｍ×１ｍｍの大きさの出力部９２が形成されている。入力部９１の一様グレーティングは、ピッチ０．４４μｍ×深さ０．２μｍ×デューティ５０％のグレーティングであり、入力部９１のクラッド９４にスタンパを押しつける事により形成される。
【００５６】
出力部９２も入力部９１と同様、凹凸で形成されるが、これは単純なグレーティングではなく、任意の波面を作り出すホログラムである。
この偽造防止シールは、コア９５を屈折率１．５２、クラッド９４、９６を屈折率１．５０のともに紫外線硬化樹脂を用いて作製する。コア９５の厚みは１μｍ、クラッド９４、９６各々の厚みは１０μｍである。これらコア９５及びクラッド９４、９６全体の厚みは２１μｍであるが、この厚みでは薄すぎて皺が寄るのを防げないので、厚み２００μｍのポリカーボネートシート９３で裏打ちされている。
【００５７】
この偽造防止シールを、ポリカーボネートシート９３の裏面９３ａで、被接着物と接着剤を介して接着させる。従って、光はその反対側の面、すなわちクラッド９６上方から入力し、回折光１００が結像して得られる再生像も接着面と反対側から観察することになる。
ここで、入力部９１への外部光の結合には注意を要する。
一般に、薄膜型ホログラムにおいては、導波路型ホログラムから外部への回折にはブラッグ条件が課せられなかった。その理由は、外部への回折光の回折角度に自由度があったためである。
【００５８】
一方、外部光の導波路への結合の場合においては、導波方向は導波路で束縛されているために、外部光に自由度を持たせなければならない。そのために、導波光の進行方向を含み、導波面に垂直な面内で入力光の進行方向を可変にしなければならない。そのため、半導体レーザ９７をボイスコイル等の振動手段を用いて紙面内で横方向に振動１０１させることで、半導体レーザ９７から出射される入力光の入射方向を振動させ、この振動する入力光を焦点距離ｆの凸レンズ９８を用いて入力部９１で平面波とする。
【００５９】
ここでは、入力部９１が小さいので、凸レンズ９８は直径が１．５ｍｍ、焦点距離ｆが３ｍｍ程度の小さな物でよい。ボイスコイル等の振動手段による半導体レーザ９７の振動１０１は数１０Ｈｚ程度で、振幅も０．１ｍｍ程度あれば十分であるから、前記振動手段にかかる負担は軽微である。
出力部９２は、回折光１００が導波路から１０ｃｍ離れた位置に、１ｃｍ×１ｃｍの大きさの像を結ぶように設計される。このように、導波路から１０ｃｍ程度離せば、像の大きさを１ｍｍ×１ｍｍの大きさから１ｃｍ×１ｃｍの大きさに拡大結像させることは容易である。また、人間の目による観察も、１ｃｍ×１ｃｍの大きさであれは容易である。
【００６０】
［第６の実施の形態］
図６は、本発明の第６の実施の形態に係る導波路ホログラム型偽造防止シールを示す図で、（ａ）は上面図、（ｂ）は側面図であり、図において、符号１１１は偽造防止シールの波長６８０ｎｍ用入カ部、１１２は同５３２ｎｍ用入力部、１１３は同出力部である。この偽造防止シールは、ポリカーボネートシート９３上に、厚み１０μｍのクラッド１１４、厚み０．７μｍの５３２ｎｍ用コア１１５、厚み１０μｍのクラッド１１６、厚み１μｍの６８０ｎｍ用コア１１７、厚み１０μｍのクラッド１１８が順次積層され、このポリカーボネートシート９３の裏面が接着面とされている。
【００６１】
また、符号１２１は波長６８０ｎｍ用半導体レーザ、１２２は波長５３２ｎｍ用光ファイバ出射端、１２３は凸レンズ、１２４はボイスコイル等の振動手段により半導体レーザ１２１に与えられる振動、１２５はボイスコイル等の振動手段により光ファイバ出射端１２２に与えられる振動である。また、１２６は導波光、１２７は回折光である。
【００６２】
この偽造防止シールは、上述した第５の実施の形態の偽造防止シールとは、幅１ｍｍ×長さ３ｃｍの細長いシートである点では同様であるが、コア層を二層備えた構成とした点が異なる。
また、上層のコア１１７が波長６８０ｎｍ用、下層のコア１１５が波長５３２ｎｍ用で、ＹＡＧ・ＳＨＧレーザのレーザ光が好適である。波長６８０ｎｍ用入カ部１１１は、５３２ｎｍ用入力部１１２に重ならないように形成される。出力部１１３は、上層のコア１１７及び下層のコア１１５に共通であるが、もちろん、層が異なる。
【００６３】
コア１１５、１１７の屈折率が１．５２、クラッド１１４、１１６、１１８の屈折率が１．５０である点は第５の実施の形態と同様である。
クラッド１１４、１１６、１１８の厚みはすべて１０μｍであるが、コア１１５の厚みは０．７μｍ、コア１１７の厚みは１μｍであるから、２００μｍの厚みのポリカーボネートシート９３と併せると、トータルで２３１．７μｍ厚となる。
６８０ｎｍ用入カ部１１１は、ピッチ０．４４μｍ×深さ０．２μｍ×デューティ５０％のグレーティングにより構成され、５３２ｎｍ用入力部１１２は、ピッチ０．３５μｍ×深さ０．２μｍ×デューティ５０％のグレーティングにより構成されている。
【００６４】
この偽造防止シールは、通常は、６８０ｎｍ用半導体レーザ１２１のみによるチェックでよいが、偽造が疑われる場合には、５３２ｎｍの回折光１２６もチェックする。ここでは、ＹＡＧ・ＳＨＧレーザ（図示せず）により出射される５３２ｎｍのレーザ光は、光ファイバ出射端１２２から出射される。
また、凸レンズ１２３およびボイスコイル等の振動手段が必要な点は、上述した第５の実施の形態と同様である。凸レンズ１２３の口径や焦点距離、ボイスコイルによる振動条件等は、第５の実施の形態と同様でよい。
【００６５】
［第７の実施の形態］
図７は、本発明の第７の実施の形態に係る導波路ホログラム型偽造防止シールの位相変調のパターンを示す模式図であり、（ａ）は２×２ピクセルからなる直交位相の全種類（ここでは、４種類）のパターンを示し、（ｂ）は４×４ピクセルからなる直交位相の全種類（ここでは、１６種類）のパターンを示し、（ｃ）及び（ｄ）は１６×１６ピクセルからなる直交位相の２５６種類のうち２種類のパターンを示している。特に、（ｃ）は本実施の形態での使用を仮定した直交位相パターンである。
これらの図では、白抜きの部分と、斜線の部分とで、位相が１８０°異なる。すなわち、白抜きの部分同士、斜線の部分同士では、それぞれ同位相である。
【００６６】
ここで、入力光が位相変調されている例について説明する。
本実施の形態の偽造防止シールでは、導波路ホログラムの形状は、入力部９１に形成されたグレーティング、および入力レンズ系である半導体レーザ９７及び凸レンズ９８を除いて、上述した第５の実施の形態と同一である。
【００６７】
まず位相変調について説明する。
一般に、Ｎ×Ｎのピクセルによる位相変調を用いた場合、Ｎ２種類の直交位相パターンが存在しうる。図７では、（ａ）２×２ピクセルによる４パターン、（ｂ）４×４ピクセルによる１６パターン、（ｃ）及び（ｄ）１６×１６ピクセルによる２５６パターンのうち２パターン、をそれぞれ示している。
【００６８】
これらは、上述した式（１）を満足している。ここで、２ｎ×２ｎ形式を例示したのは、各ピクセルの位相を０゜もしくは１８０°の二種類のみとすることができるからであり、入力光の位相変調用位相マスクを作製するのに都合が良いからである。
ここで、（ｃ）に示されるような市松模様の位相パターンを選んだとする。この図では、白と黒では１８０°位相が異なる。
入力部９１は１ｍｍ×１ｍｍの大きさであるから、１６×１６ピクセルである位相パターンは、各ピクセルサイズが６２．５μｍ×６２．５μｍである。
【００６９】
図８は本実施の形態の偽造防止シールに適用される入力光学系を示す構成図であり、（ａ）は実位相パターン方式の光学系、（ｂ）はフーリエ位相パターン方式の光学系である。
図において、１３１は偽造防止シールの入力部、１３２は位相マスク（位相変調手段）、１３３は凸レンズ、１３４は半導体レーザ、１３５は図示しないボイスコイルによる振動、１３６はフーリエ変換レンズ、１３７はコリメートレンズである。凸レンズ１３３は直径１．５ｍｍ、焦点距離ｆ＝３ｍｍ程度のものが用いられる。
【００７０】
実位相パターン方式（ａ）では、位相マスク１３２は偽造防止シールの入力部１３１にほぼ密着して配置される。位相マスク１３２はガラスエッチングもしくはプラスチック材料のスタンピングによって作製することができるが、ここでは屈折率１．５のプラスチックをマスクとして用いる。位相マスク１３２と偽造防止シールの位相変調は同じサイズでなけれはならない。位相マスク１３２は、図７（ｃ）の黒部分に対応する部分に凹部を、白部分に対応する部分に凸部をそれぞれ配置し、これらの高度差は４５０ｎｍでなけれはならない。
【００７１】
この偽造防止シールの入力部に関しては、例えば、第２の実施の形態においては、図７（ｃ）の黒部分が領域Ａに、白部分が領域Ｂにそれぞれ相当しており、４５０ｎｍの高度差を有するように作製される。
また、第３の実施の形態においては、図７（ｃ）の黒部分が領域Ａに、白部分が領域Ｂにそれぞれ相当しており、領域Ａと領域Ｂとでグレーティングの位相が反転する構成とされている。
【００７２】
一方、フーリエパターン方式（ｂ）では、位相マスク１３２は実位相パターン方式と同じものを用いる。フーリエ変換レンズ１３６は実位相パターン方式の凸レンズ１３３と同じものを用いるが、位相マスク１３２のフーリエ像が偽造防止シールの入力部１３１にて結像される位置に配置する。コリメートレンズ１３７はレーザ光をコリメートするために設けられるもので、焦点距離はｆ’＝２ｍｍ程度あれば良い。
【００７３】
ただし、偽造防止シールとしては、入力部１３１の位相パターンが位相マスク１３２のフーリエ変換の複素共役の位相パターンで与えられるので、各ピクセルの位相は二種類では与えられず、複雑なパターンとなる。
ただし、この方法のメリットは、入力ビームの位置ずれに対して許容度が大きくなるという点にある。
【００７４】
また、本発明の偽造防止シールを「錠前」とし、位相マスク１３２を「鍵」とすれば、「錠前」と「鍵」、すなわち本発明の偽造防止シールと位相マスク１３２が合致するか否かで認証を行うことができる。この場合、本発明の偽造防止シールと位相マスク１３２が合致するか否かを認識した段階で、認証の可否を直ちに判定することができる。
さらに、複数のホログラムが積層された偽造防止シールを用いれば、安全性のレベルを上げることができる。
【００７５】
［第８の実施の形態］
本発明の第８の実施の形態に係る導波路ホログラム型偽造防止シールは、第５の実施の形態の偽造防止シールとほぼ同等の偽造防止シールを用いる。ただし、コアの材料が異なる。
【００７６】
また、この偽造防止シールを備えた物品は、図４に示す透明カバーシール７３として、厚み０．２ｍｍのアートン樹脂のシートを用いる。被接着物７１は紙である。
接着部７４〜７６は全て二液混合タイプのエポキシ系接着剤を用いる。また、コア８２にフッ素添加の紫外線硬化樹脂を用いることで、コア８２とクラッド８１、８３との間の接着強度を弱める。
【００７７】
以上、本発明の各実施の形態につき説明したが、本発明は、必ずしも上述した実施の形態にのみ限定されるものではなく、本発明にいう目的を達成し、本発明にいう効果を有する範囲内において、適宜に変更実施することが可能なものである。
【００７８】
【発明の効果】
以上説明した様に、本発明の導波路ホログラム型偽造防止シールを備えた物品によれば、被接着物と偽造防止シールとの間の接着強度、偽造防止シールと透明シールとの間の接着強度、及び透明シールと被接着物との間の接着強度を、光導波路のコアとクラッドとの間の接着強度より大きいとしたので、簡単に貼ることができ、しかも、剥がしたとしても当初の状態に戻すことができず、二度と使用することができない。これを商品パッケージ等に適用すれば、この商品パッケージ等の未開封を証明することができる。
【００８２】
以上により、本発明によれば、従来、基準とされた（１）偽造することが極めて困難であること、（２）正当な製造者は安価に製造することができること、（３）真贋の判別が容易であること、（４）簡単に貼ることができるが、剥がすことは困難であること、（５）たとえ剥がすことができたとしても、剥がすと二度と使えなくなること、（６）重要度に応じてセキュリティレベルを変更することができること、等を満たすことができ、偽造防止、及び携帯者の正当性を認証するための導波路ホログラム型偽造防止シールとそれを備えた物品及びそれを用いた認証方法を提供することができる。
【図面の簡単な説明】
【図１】本発明の第１の実施形態に係る導波路ホログラム型偽造防止シールを示す図であり、（ａ）は側面図、（ｂ）は上面図、（ｃ）は入力部を拡大した一部拡大断面図である。
【図２】本発明の第２の実施の形態に係る導波路ホログラム型偽造防止シールを示す断面図であり、（ａ）は入力光が導波路に結合しない場合、（ｂ）は入力光が導波路に接合する場合である。
【図３】本発明の第３の実施の形態に係る導波路ホログラム型偽造防止シールを示す断面図であり、（ａ）は入力光が導波路に結合しない場合、（ｂ）は入力光が導波路に接合する場合である。
【図４】本発明の第４の実施の形態に係る導波路ホログラム型偽造防止シールを備えた物品を示す部分断面図である。
【図５】本発明の第５の実施の形態に係る導波路ホログラム型偽造防止シールを示す図であり、（ａ）は上面図、（ｂ）は側面図である。
【図６】本発明の第６の実施の形態に係る導波路ホログラム型偽造防止シールを示す図であり、（ａ）は上面図、（ｂ）は側面図である。
【図７】本発明の第７の実施の形態に係る導波路ホログラム型偽造防止シールの位相変調のパターンの様々な例を示す模式図である。
【図８】本発明の第７の実施の形態に係る導波路ホログラム型偽造防止シールに適用される入力光学系を示す構成図であり、（ａ）は実位相パターン方式の光学系、（ｂ）はフーリエ位相パターン方式の光学系である。
【図９】再生専用多重ホログラムカードを示す断面図である。
【符号の説明】
１ 再生専用多重ホログラムカード
２−１〜２−ｎ クラッド
３−１〜３−ｎ−１ コア
４ 反射面
５ レーザー光
６ 凸レンズ
７ 導波光
８ 散乱要因
９ 回折光
１０ ホログラム像
１１ 入力部
１２ 出力部
１３ クラッド
１４ コア
１５ クラッド
１６ グレーティング
２１ 外部光
２２ 導波光
２３ 回折光
３１、３３、３６、３８ クラッド
３２、３７ コア
３４、３９ 凹凸
３５、４０ 一様グレーティング
４１ 平面波の入力光
４２ 変調された入力光
４３ 予め位相変調された入力光
４４ 平面波に変換された入力光
４５ 導波光
５１、５３、５６、５８ クラッド
５２、５７ コア
５４、５９ 反転したグレーティング
６１、６２ 平面波の入力光
６３、６４ 予め位相変調された入力光
６５ 導波光
７１ 被接着物
７２ 導波路ホログラム型偽造防止シール
７３ 透明カバーシール（透明シール）
７４〜７６ 接着部
８１、８３ クラッド
８２ コア
９１ 入力部
９２ 出力部
９３ ポリカーボネートシート
９４、９６ クラッド
９５ コア
９７ 半導体レーザ
９８ 凸レンズ
９９ 導波光
１００ 回折光
１０１ 振動
１１１ ６８０ｎｍ用入カ部
１１２ ５３２ｎｍ用入力部
１１３ 出力部
１１４、１１６、１１８ クラッド
１１５ ５３２ｎｍ用コア
１１７ ６８０ｎｍ用コア
１２１ ６８０ｎｍ用半導体レーザ
１２２ 光ファイバ出射端
１２３ 凸レンズ
１２４、１２５ 振動[0001]
TECHNICAL FIELD OF THE INVENTION
The present inventionRegarding an article provided with a waveguide hologram type forgery prevention seal,More specifically, it has the same functions as watermarks and micro-characters on banknotes, holograms on credit cards, etc., and can be applied to items that are relatively easy to forge, such as passports, licenses, insurance cards, and various membership cards. It is possible to guarantee the legitimacy of these carriers or to prove the unopened of the product package etc. by applying to the product package etc.Article with waveguide hologram type forgery prevention sealThings.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in banknotes, credit cards, passports, licenses, insurance cards, various membership cards, and the like, a technique for preventing counterfeiting by attaching a material requiring advanced technology to manufacture has been used. For example, watermarks and micro-characters on banknotes, holograms on credit cards, and the like. However, since these examples are made when manufacturing banknotes and cards, they are applied to the case where a large number of identical items are manufactured. It does not provide forgery prevention.
In order to prevent counterfeiting of the article by applying a certain seal to the manufactured article and to improve safety at the same time, it is desirable that the sticker to be applied satisfies the following criteria.
[0003]
(1) It is extremely difficult to forge.
(2) A legitimate manufacturer can manufacture it at low cost.
(3) It is easy to determine authenticity.
(4) Easy to attach, but difficult to remove.
(5) Even if it can be peeled off, if it is peeled off, it can no longer be used.
(6) The level of security can be changed according to the degree of importance.
And so on.
[0004]
On the other hand, a holographic information recording medium using holography has been proposed as an information recording medium that is difficult to forge and has a large storage capacity.
However, in conventional hologram information recording media, those with excellent storage capacity cannot be mass-produced, and those that can be mass-produced by applying printing technology have a large storage capacity because the storage density is limited. There are various problems such as inability to do so. Thus, the present inventors have used the principle of a plane hologram that is difficult to forge and can be mass-produced, and have made it possible to superimpose this plane hologram in multiple layers and reproduce the holograms from each layer independently. A reproduction-only multiplex hologram card was proposed (Japanese Patent Application No. 10-32578).
[0005]
FIG. 9 is a cross-sectional view showing the read-only multiplexed hologram card. The read-only multiplexed hologram card 1 is composed of / clad 2-1 / core 3-1 / clad 2-2 / ... core 3-n-1 / The end of the periodic layer structure such as the cladding 2-n / is a reflection surface 4 of 45 °. Each of the cladding / core / cladding / unit is a planar single mode waveguide with respect to the wavelength of the laser beam 5 to be used.
In the reproduction-only multiplex hologram card 1, when a core and a clad are manufactured using a normal polymer material having a refractive index of about 1.48, the thickness of the core needs to be 2.4 μm or less from a single mode condition. . Further, in order to suppress crosstalk between cores, it is necessary to make the thickness of the clad sufficiently thicker than 6 μm.
[0006]
In this reproduction-only multiplex hologram card 1, the laser beam 5 is condensed by the convex lens 6 so as to focus on the 45 ° cut position of each core (core 3-5 in FIG. 3), and is reflected by the reflection surface 4. The light propagates as guided light 7 in each core (core 3-5 in FIG. 3). The guided light 7 is diffracted by the scattering factor 8 while propagating in the core 3-5 and appears as a diffracted light 9 outside the core 3-5. The diffracted light 9 forms a hologram image 10.
[0007]
[Problems to be solved by the invention]
By the way, as forgery technology advances along with the general technological level of the world, if the same technology is used, the condition of the criterion (1) will not be satisfied. For example, in the method of attaching magnetic information, forgery has already been performed relatively easily, and forgery damage has occurred in various places. In addition, a normal hologram seal is not safe because the hologram manufacturing technology is not a technology that can be monopolized by a limited number of organizations and does not satisfy the criterion (5).
[0008]
Further, when the above-described reproduction-only multiplex hologram card is sealed, the criterion (1) and the criterion (2) can be easily achieved as described later. However, in the conventional waveguide hologram, the criterion after the criterion (3) is used. not filled. For example, in order to obtain a diffraction image, light must be coupled at least to the waveguide, but at least a human hand must be used to accurately match a focused beam to a core layer having a thickness of only about 1 μm. As far as possible, there was a problem that very rare coincidences had to be expected.
[0009]
The present invention has been made in view of the above circumstances, and has the same functions as watermarks and micro-characters in banknotes, holograms in credit cards, and the like, and furthermore, passports, licenses, insurance cards, and various membership cards. By applying it to something that is relatively easy to counterfeit, the legitimacy of these carriers can be guaranteed, and by applying it to a product package, etc., it is proved that the product package, etc. has not been opened. be able toProvide an article provided with a waveguide hologram type forgery prevention sealIt is in.
[0010]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides the following:An article provided with a waveguide hologram type forgery prevention seal was employed.
That is,In the article provided with the waveguide hologram type forgery prevention seal of the present invention, holograms are formed at a plurality of locations of the single mode planar optical waveguide, and at least one of these holograms is incident on the optical waveguide from outside. An external light coupling hologram is formed by combining external light to be guided inside the optical waveguide to form guided light, and at least one other hologram is formed outside the optical waveguide by diffracted light obtained by diffracting the guided light. An article provided with a waveguide hologram type forgery prevention seal in which a plurality of the optical waveguides are laminated, and the grating of the external optical coupling hologram has a different grating period depending on the layer. The anti-counterfeit seal is adhered to, and a transparent seal is adhered so as to cover at least the anti-counterfeit seal, and the adhesion between the adherend and the anti-counterfeit seal The adhesive strength between the anti-counterfeit seal and the transparent seal, and the adhesive strength between the transparent seal and the object to be bonded are larger than the adhesive strength between the core and the clad of the optical waveguide. It is characterized by.
[0022]
Article provided with this waveguide hologram type forgery prevention sealThen, the anti-counterfeit seal of the present invention is adhered on the adherend, a transparent seal is adhered so as to cover at least the anti-counterfeit seal, the adhesive strength between the adherend and the anti-counterfeit seal, the forgery By making the adhesive strength between the prevention seal and the transparent seal, and the adhesive strength between the transparent seal and the adherend larger than the adhesive strength between the core and the clad of the optical waveguide, It can be easily pasted, and it is difficult to peel it off. Even if it can be peeled off, it is impossible to return to the original state, so that it cannot be used again.
If this is applied to a product package or the like, it becomes possible to prove that the product package or the like has not been opened.
[0025]
When the present invention is further described, the criterion (1) is satisfied by employing the technique of the waveguide hologram in view of the above-mentioned six criteria. To reproduce the hologram, a laser is used even for visible light in consideration of "viewing with the eyes". However, if necessary, a light receiving device such as a CCD or a CMOS detector and an image recognition technique may be used.
Here, using a laser for visible light contributes to improvement of security because it is difficult for a general user to know what information is written.
[0026]
The light source may be any laser for visible light having a coherence length of several mm or more, and it is possible to form a waveguide hologram according to the wavelength. More specifically, the wavelength may be set according to the required security level. For example, the shorter the wavelength is, the more difficult it is to manufacture a waveguide hologram. Therefore, the security level against forgery is improved, and it is generally difficult to obtain a short wavelength laser light source.
[0027]
However, from the viewpoint of cost effectiveness, it is preferable to use an inexpensive red semiconductor laser used as a light source for reproducing a compact disc. Also in this case, the unevenness of the hologram must be drawn with an ultrafine line having a thickness of 0.2 μm or less at a pitch of 0.5 μm with respect to a red laser beam having a wavelength of 780 nm. However, at the current technical level, such a technique for drawing such a fine line can be implemented only by a limited number of organizations, so that, for example, a malicious third party can obtain the technique for drawing such a fine line in hand. The likelihood of doing is small.
Further, since a technology for forming an optical waveguide is required, it is necessary to have both a microfabrication technology and a waveguide technology. In order for such a technology to become widespread, it will still require a time period of about 10 years.
[0028]
By the way, when the wavelength of the laser beam is 410 nm, the hologram has irregularities of 0.3 μm pitch and requires ultra-fine line processing of 0.1 μm or less. Therefore, an electron beam lithography system or a deep UV lithography system is required to manufacture the master. Is required. These devices are technologies that have already been established and held in some research institutes and the like, but will require more years to spread to the general public.
On the other hand, if the institution has mastering and waveguide conversion technology, it is an advantage of the waveguide hologram that mass production is possible. Therefore, the above criteria (1) and (2) are based on the waveguide hologram itself. The properties are satisfied to some extent.
[0029]
BEST MODE FOR CARRYING OUT THE INVENTION
Less than,About each embodiment of the present inventionThis will be described with reference to the drawings.
[0030]
[First Embodiment]
FIGS. 1A and 1B are views showing a waveguide hologram type forgery prevention seal according to a first embodiment of the present invention, wherein FIG. 1A is a side view, FIG. 1B is a top view, and FIG. In the figure, reference numeral 11 denotes an input portion, 12 denotes an output portion on which a hologram is formed, 13 denotes a cladding constituting a waveguide, 14 denotes the same core, 15 denotes the same cladding, and 16 denotes a period. Denotes a grating having fine irregularities of λ / n. Reference numeral 21 denotes external light composed of a plane wave, 22 denotes guided light, and 23 denotes diffracted light.
This anti-counterfeit seal is a modified version of the method of coupling external light to the waveguide hologram in order to satisfy the above criterion (3), and has a configuration in which external light is coupled by the grating 16.
[0031]
Next, the external optical coupling method will be described with reference to FIG. Here, for the sake of simplicity, it is assumed that the core 14 has only one layer. External light 21 which is a plane wave is applied to the input unit 11. In the input unit 11, a grating 16 having a period of λ / n is formed in the waveguide, where λ is the wavelength of the used light in the air and n is the refractive index of the core.
At this time, the interaction between the grating 16 having a period of λ / n and the external light 21 generates the guided light 22 that travels in the direction of the grating vector. Here, if the output unit 12 in which the hologram is formed is formed in the direction of the grating vector of the input unit 11, the diffracted light 23 can be obtained.
[0032]
By adopting such an external optical coupling method, the above-mentioned criterion (3) can be satisfied. Since the size of the light beam of the input unit 11 is a size of millimeter (mm), it is easy to perform "manual" alignment by preparing a plane wave 21 having a light beam larger than that. Further, since the diffracted light 23 can be visually recognized, there is no need to prepare a CCD or other light receiver. However, as described above, when the automatic recognition area is required, a two-dimensional light receiver such as a CCD or a CMOS detector may be used in combination with the image recognition technology.
[0033]
Now, as the characteristics of the waveguide hologram, although the above-described criteria (1) and (2) are satisfied to some extent, even if the institution has a technology for manufacturing a waveguide hologram, it is a legitimate manufacturer. It is important to provide a mechanism that cannot produce the same product unless otherwise, in order to satisfy the criterion (6). A waveguide hologram type forgery prevention seal described below is provided with this mechanism.
[0034]
[Second embodiment]
FIG. 2 is a cross-sectional view showing a waveguide hologram type forgery prevention seal according to a second embodiment of the present invention. FIG. 2A shows a case where input light is not coupled to the waveguide, and FIG. The case where the optical waveguide is bonded to a waveguide is shown.
[0035]
In the figure, reference numeral 31 denotes a clad, 32 denotes a core, 33 denotes a clad, 34 denotes a surface irregularity, 35 denotes a uniform grating in a waveguide, 36 denotes a clad, 37 denotes a core, 38 denotes a clad, 39 denotes a surface irregularity, 40 is a uniform grating in the waveguide. Reference numeral 41 denotes input light of a plane wave, reference numeral 42 denotes input light modulated by surface irregularities 34, reference numeral 43 denotes input light which has been phase-modulated in advance so that it can be coupled to a waveguide, and reference numeral 44 denotes a surface wave converted by the surface irregularities 39 to a plane wave. Input light 45 is guided light.
[0036]
This anti-counterfeit seal applies phase modulation to the light wavefront and uses the phase modulation pattern as an encryption key.
Here, phase modulation and its encryption key will be described.
The result is different between the case where the input light is not coupled to the waveguide (a) and the case where the input light is coupled to the waveguide (b) because the phases of the input lights 41 and 43 are different.
[0037]
In the case where the input light is not coupled to the waveguide (a), since the input light 41 is a plane wave, the input light 41 is modulated by the unevenness 34 formed on the surface of the clad 33 to become the input light 42. The phase of the wavefront of the input light 42 is delayed at the convex portion (region A) and relatively advanced at the concave portion (region B). Therefore, if the phase of the wavefront of the input light 42 is shifted by 180 ° between the area A and the area B, the light reaches the core 32 and the lights diffracted by the grating 35 cancel each other. Therefore, the input light 41, which is external light, is not coupled to the waveguide, and no reproduced light is obtained because there is no guided light.
[0038]
On the other hand, in the case where the input light is coupled to the waveguide (b), the phase of the input light 43 is previously manipulated, and the unevenness 39 on the clad 36 causes a plane wave when the input light 43 enters the clad 36. It is adjusted so as to be converted input light 44. In this case, the guided light reinforces each other in the region A and the region B, coupling between the external light and the waveguide occurs, and the guided light 45 is generated. Therefore, a reproduced image from the output unit can be observed.
[0039]
Now, from the viewpoint of controlling the coupling strength between the external light and the guided light, it is the same as the above-described second embodiment, but instead of forming irregularities on the cladding, modulation is performed on the grating itself in the input part. It is also possible to call. This configuration is the waveguide hologram type forgery prevention seal described below.
[0040]
[Third Embodiment]
3A and 3B are cross-sectional views showing a waveguide hologram type forgery prevention seal according to a third embodiment of the present invention. FIG. 3A shows a case where input light is not coupled to the waveguide, and FIG. The case where the optical waveguide is bonded to a waveguide is shown.
[0041]
In the figure, reference numeral 51 denotes a clad, 52 denotes a core, 53 denotes a clad, 54 denotes a grating inverted in a region A and a region B, 56 denotes a clad, 57 denotes a core, 58 denotes a clad, and 59 denotes a reversed in the regions A and B. It is a grating. Further, 61 is input light of a plane wave, 62 is input light as a plane wave traveling in the cladding 56, 63 is input light which has been phase-modulated in advance so as to be coupled to the waveguide, and 64 is phase-modulated traveling in the cladding 56. The input light as it is, 65 is the guided light.
[0042]
The case where the input light is not coupled to the waveguide (a) and the case where the input light is coupled to the waveguide (b) have the same structure, but similar to the second embodiment, The results are different because the lights 61 and 63 are different.
When the input light is not coupled to the waveguide (a), the input light 61 is a plane wave, and here, unlike FIG. 2, the surface of the clad 51 has no irregularities, so that the input light 62 traveling through the clad 51 is also a plane wave. . However, the inverted grating 54 in the region A and the region B formed in the core 52 is modulated, and the region A and the region B generate guided light having a phase different from each other by 180 °. Therefore, since the input light 61, which is external light, does not couple with the waveguide, a reproduced image cannot be obtained.
[0043]
On the other hand, in the case where the input light is coupled to the waveguide (b), since the phase of the input light 63 is modulated in anticipation of the modulation of the grating 59, the guided lights generated in the regions A and B are strengthened. . As a result, guided light 65 is generated, and a reproduced image is obtained.
Also in this forgery prevention seal, a reproduced image can be obtained only with the modulation of external light.
[0044]
In the forgery prevention seals of the second and third embodiments described above, it is possible to obtain a reproduced image only when external light is modulated. Here, the phase modulation pattern plays the role of an encryption key. Here, for example, if the unit of the phase modulation is 2 μm and the size of the input unit is 1 mm square, the phase modulation is 500 × 500 pixels. Further, the phase patterns orthogonal to each other have the same pattern type as the number of pixels, so that 250,000 types of patterns can be taken.
[0045]
Here, “the phases are orthogonal” means that the phase of the (i, j) -th pixel in the phase patterns α and β is
(Equation 1)

(Equation 2)

And when
(Equation 3)

It is to satisfy.
However,
(Equation 4)

Is Kronecker's Delta.
[0046]
Generally, unlike an amplitude mask, it is expensive to manufacture a phase mask. Therefore, the task of trying out all 250,000 types of phase masks requires enormous cost and time. Therefore, it is difficult to copy even an institution having a waveguide hologram manufacturing technique unless it knows the phase modulation pattern, and it can be understood that the above-mentioned criterion (6) is satisfied.
[0047]
In the forgery prevention seals of the second and third embodiments, the level of security is further increased by adding a configuration in which the period of the grating of the external light coupling hologram of each layer is different depending on the layer as necessary. It is possible.
When counterfeiting is suspected, use layers, wavelengths and phase patterns that are not normally used.
When this configuration is added to the forgery prevention seal of the second embodiment, it is necessary to arrange the input portions so that they do not overlap each other. However, this configuration is different from the forgery prevention seal of the third embodiment. , The input units may overlap each other.
[0048]
Assuming the same size as above due to two input sections, there can be 250,000 types of phase patterns. Therefore, there are 250,000 × 250,000 types, that is, 62.5 billion types of phase patterns in both cases. Decrypting and falsifying this is effectively "impossible". It is also effective to keep the wavelength of the second layer and the existence of the second layer secret, in order to increase the security level.
[0049]
The above-described criterion (4) can be satisfied by using an adhesive that is difficult to peel off, for example, a two-liquid mixed type epoxy-based adhesive. A more difficult criterion is the criterion (5), which has a function of confirming the history of peeling in the event that the film is peeled. This configuration is an article provided with the waveguide hologram type forgery prevention seal described below.
[0050]
[Fourth Embodiment]
FIG. 4 is a partial cross-sectional view showing an article provided with a waveguide hologram type forgery prevention seal according to a fourth embodiment of the present invention. In the figure, reference numeral 71 denotes an adherend, and 72 denotes a waveguide hologram type. Forgery prevention seal, 73 is a transparent cover seal (transparent seal), 74 is an adhesion part between the adherend 71 and the transparent cover seal 73, 75 is an adhesion part between the forgery prevention seal 72 and the transparent cover seal 73, and 76 is a forgery prevention This is a bonding portion between the seal 72 and the object 71.
[0051]
The adherend 71 is, specifically, a passport paper, various licenses, or a membership card itself.
The forgery prevention seal 72 includes a clad 81, a core 82, and a clad 83. Here, only one core 82 of the forgery prevention seal 72 is shown, but a plurality of cores may be provided.
[0052]
Here, the adhesive strength between the adherend 71 and the transparent cover seal 73 is Asb, the adhesive strength between the adherend 71 and the forgery prevention seal 72 is Awb, and the adhesion between the transparent cover seal 73 and the forgery prevention seal 72 is Asb. Assuming that the adhesive strength is Asw and the adhesive strength between the core 82 and the clads 81 and 83 is Acc,
Asb >> Acc (2-1)
Awb >> Acc ...... (2-2)
Asw >> Acc ... (2-3)
Meets.
[0053]
That is, the adhesive strength between the adherend 71 and the forgery prevention seal 72, the adhesive strength between the forgery prevention seal 72 and the transparent cover seal 73, and the adhesive strength between the transparent cover seal 73 and the adherend 71. Is larger than the adhesive strength between the core 82 of the optical waveguide and the claddings 81 and 83.
As described above, if an attempt is made to peel off the transparent cover seal 73, it will be peeled off at the bonding portion between the core 82 and the claddings 81 and 83 before the transparent cover seal 73 is peeled off, and the light will never be guided again. There is no. Therefore, the above-described criterion (5) can be satisfied.
[0054]
[Fifth Embodiment]
5A and 5B are views showing a waveguide hologram type forgery prevention seal according to a fifth embodiment of the present invention, wherein FIG. 5A is a top view, and FIG. 5B is a side view. The input part 92 of the prevention seal is the same output part. In the forgery prevention seal, a clad 94, a core 95, and a clad 96 are sequentially laminated on a polycarbonate sheet 93, and the back surface of the polycarbonate sheet 93 is an adhesive surface. Reference numeral 97 denotes a semiconductor laser, 98 denotes a convex lens, 99 denotes guided light, 100 denotes diffracted light, and 101 denotes vibration applied to the semiconductor laser 97 by vibration means such as a voice coil.
[0055]
As the semiconductor laser 97, a 680 nm red semiconductor laser used as a light source for a magneto-optical disk is preferably used.
This forgery prevention seal is an elongated sheet having a thickness of 221 μm, a width of 1 mm, and a length of 3 cm. An input unit 91 made of a uniform grating of 1 mm × 1 mm is formed at one end in the longitudinal direction of the sheet, and an output unit 92 of 1 mm × 1 mm is formed at the other end. The uniform grating of the input unit 91 is a grating having a pitch of 0.44 μm × depth of 0.2 μm × duty of 50%, and is formed by pressing a stamper against the clad 94 of the input unit 91.
[0056]
Similarly to the input unit 91, the output unit 92 is formed with irregularities, but is not a simple grating but a hologram that creates an arbitrary wavefront.
This anti-counterfeit seal is manufactured by using an ultraviolet curable resin for both the core 95 with a refractive index of 1.52 and the clads 94 and 96 with a refractive index of 1.50. The thickness of the core 95 is 1 μm, and the thickness of each of the clads 94 and 96 is 10 μm. The overall thickness of the core 95 and the claddings 94 and 96 is 21 μm, but this thickness is too thin to prevent wrinkling, and is therefore backed by a 200 μm thick polycarbonate sheet 93.
[0057]
The anti-counterfeit seal is adhered to the adherend with an adhesive on the back surface 93a of the polycarbonate sheet 93. Therefore, light enters from the opposite surface, that is, from above the cladding 96, and the reproduced image obtained by forming the diffracted light 100 is also observed from the opposite side to the bonding surface.
Here, care must be taken in coupling external light to the input unit 91.
In general, in a thin film hologram, no Bragg condition is imposed on the diffraction from the waveguide hologram to the outside. The reason is that there was a degree of freedom in the diffraction angle of the diffracted light to the outside.
[0058]
On the other hand, in the case where external light is coupled to the waveguide, the external light must have a degree of freedom since the waveguide direction is restricted by the waveguide. For this purpose, the traveling direction of the input light must be variable within a plane including the traveling direction of the guided light and perpendicular to the waveguide surface. For this reason, the semiconductor laser 97 is vibrated 101 in the horizontal direction in the plane of the drawing by using a vibrating means such as a voice coil to vibrate the incident direction of the input light emitted from the semiconductor laser 97 and focus the vibrating input light. A plane wave is generated at the input unit 91 using the convex lens 98 having a distance f.
[0059]
Here, since the input section 91 is small, the convex lens 98 may be a small one having a diameter of 1.5 mm and a focal length f of about 3 mm. The vibration 101 of the semiconductor laser 97 by the vibrating means such as a voice coil is about several tens Hz and the amplitude is about 0.1 mm is sufficient, so that the load on the vibrating means is small.
The output unit 92 is designed so that the diffracted light 100 forms an image of 1 cm × 1 cm at a position 10 cm away from the waveguide. As described above, if the distance from the waveguide is about 10 cm, it is easy to form an enlarged image from 1 mm × 1 mm to 1 cm × 1 cm. Observation by human eyes is easy if the size is 1 cm × 1 cm.
[0060]
[Sixth Embodiment]
6A and 6B are views showing a waveguide hologram type forgery prevention seal according to a sixth embodiment of the present invention, wherein FIG. 6A is a top view, and FIG. 6B is a side view. An input part for the wavelength of 680 nm of the prevention seal, an input part 112 for the wavelength of 532 nm, and an output part 113 for the prevention seal. In this anti-counterfeit seal, a 10 μm thick cladding 114, a 0.7 μm thick 532 nm core 115, a 10 μm thick cladding 116, a 1 μm thick 680 nm core 117, and a 10 μm thick cladding 118 are sequentially laminated on a polycarbonate sheet 93. The rear surface of the polycarbonate sheet 93 is an adhesive surface.
[0061]
Reference numeral 121 denotes a semiconductor laser for a wavelength of 680 nm, reference numeral 122 denotes an emission end of an optical fiber for a wavelength of 532 nm, reference numeral 123 denotes a convex lens, reference numeral 124 denotes vibration applied to the semiconductor laser 121 by a vibration means such as a voice coil, and reference numeral 125 denotes vibration means such as a voice coil. Is the vibration given to the optical fiber output end 122 by the Reference numeral 126 denotes guided light, and 127 denotes diffracted light.
[0062]
This anti-counterfeit seal is the same as the anti-counterfeit seal of the fifth embodiment described above in that it is an elongated sheet having a width of 1 mm and a length of 3 cm, but has a configuration including two core layers. Are different.
The upper core 117 has a wavelength of 680 nm, and the lower core 115 has a wavelength of 532 nm. A YAG / SHG laser beam is preferable. The input section 111 for the wavelength of 680 nm is formed so as not to overlap the input section 112 for the 532 nm. The output unit 113 is common to the upper core 117 and the lower core 115, but, of course, the layers are different.
[0063]
As in the fifth embodiment, the cores 115 and 117 have a refractive index of 1.52, and the clads 114, 116 and 118 have a refractive index of 1.50.
The claddings 114, 116, and 118 all have a thickness of 10 μm, but the core 115 has a thickness of 0.7 μm and the core 117 has a thickness of 1 μm. Therefore, when combined with the polycarbonate sheet 93 having a thickness of 200 μm, the total is 231.7 μm. Become thick.
The input section 111 for 680 nm is constituted by a grating having a pitch of 0.44 μm × 0.2 μm in depth × 50% duty, and the input section 112 for 532 nm is provided with a pitch of 0.35 μm × 0.2 μm in depth × 50% duty. It consists of a grating.
[0064]
Normally, the forgery prevention seal may be checked only by the semiconductor laser 121 for 680 nm, but if forgery is suspected, the 532 nm diffracted light 126 is also checked. Here, 532 nm laser light emitted by a YAG / SHG laser (not shown) is emitted from the optical fiber emission end 122.
Further, the point that the vibration means such as the convex lens 123 and the voice coil are required is the same as in the above-described fifth embodiment. The aperture and focal length of the convex lens 123, the vibration conditions by the voice coil, and the like may be the same as those in the fifth embodiment.
[0065]
[Seventh Embodiment]
FIGS. 7A and 7B are schematic diagrams showing a phase modulation pattern of a waveguide hologram type forgery prevention seal according to a seventh embodiment of the present invention. FIG. 7A shows all types of quadrature phases (2 × 2 pixels) ( Here, four types of patterns are shown, (b) shows patterns of all types (here, 16 types) of quadrature composed of 4 × 4 pixels, and (c) and (d) show 16 × 16 pixels 2 patterns out of 256 types of quadrature phases consisting of In particular, (c) is a quadrature pattern assumed to be used in the present embodiment.
In these figures, the phase differs by 180 ° between the white portion and the hatched portion. That is, the white portions and the hatched portions have the same phase.
[0066]
Here, an example in which the input light is phase-modulated will be described.
In the forgery prevention seal of the present embodiment, the shape of the waveguide hologram is the same as that of the fifth embodiment described above except for the grating formed in the input section 91 and the semiconductor laser 97 and the convex lens 98 as the input lens system. Is the same as
[0067]
First, phase modulation will be described.
In general, when phase modulation using N × N pixels is used, there are N2 types of quadrature patterns. FIG. 7 shows (a) four patterns of 2 × 2 pixels, (b) 16 patterns of 4 × 4 pixels, and (c) and (d) two of 256 patterns of 16 × 16 pixels. .
[0068]
These satisfy Expression (1) described above. Here, the 2n × 2n format is exemplified because each pixel can have only two phases of 0 ° or 180 °, which is convenient for manufacturing a phase mask for phase modulation of input light. Is good.
Here, it is assumed that a checkerboard phase pattern as shown in (c) is selected. In this figure, the 180 ° phase differs between white and black.
Since the input unit 91 has a size of 1 mm × 1 mm, the phase pattern of 16 × 16 pixels has a pixel size of 62.5 μm × 62.5 μm.
[0069]
FIGS. 8A and 8B are configuration diagrams showing an input optical system applied to the forgery prevention seal of the present embodiment. FIG. 8A shows an optical system of a real phase pattern system, and FIG. 8B shows an optical system of a Fourier phase pattern system. .
In the figure, 131 is an input part of a forgery prevention seal, 132 is a phase mask (phase modulation means), 133 is a convex lens, 134 is a semiconductor laser, 135 is vibration by a voice coil (not shown), 136 is a Fourier transform lens, 137 is a collimating lens It is. The convex lens 133 has a diameter of 1.5 mm and a focal length f of about 3 mm.
[0070]
In the actual phase pattern method (a), the phase mask 132 is arranged almost in close contact with the input section 131 of the forgery prevention seal. The phase mask 132 can be manufactured by glass etching or stamping of a plastic material. Here, plastic having a refractive index of 1.5 is used as a mask. The phase modulation of the phase mask 132 and the anti-counterfeit seal must be the same size. In the phase mask 132, a concave portion is arranged in a portion corresponding to a black portion in FIG. 7C, and a convex portion is arranged in a portion corresponding to a white portion, and the height difference between them must be 450 nm.
[0071]
Regarding the input part of the forgery prevention seal, for example, in the second embodiment, the black part in FIG. 7C corresponds to the area A and the white part corresponds to the area B, and the altitude difference of 450 nm. It is made to have.
In the third embodiment, the black portion in FIG. 7C corresponds to the region A and the white portion corresponds to the region B, and the phase of the grating is inverted between the region A and the region B. It has been.
[0072]
On the other hand, in the Fourier pattern method (b), the same phase mask as the real phase pattern method is used as the phase mask 132. The Fourier transform lens 136 is the same as the real phase pattern type convex lens 133, but is arranged at a position where the Fourier image of the phase mask 132 is formed at the input section 131 of the forgery prevention seal. The collimating lens 137 is provided for collimating the laser light, and the focal length may be about f '= 2 mm.
[0073]
However, as the anti-counterfeit seal, since the phase pattern of the input unit 131 is given by the phase pattern of the complex conjugate of the Fourier transform of the phase mask 132, the phase of each pixel is not given by two types and becomes a complicated pattern..
However,The advantage of this method is that the tolerance for the displacement of the input beam is increased.
[0074]
Further, if the anti-counterfeit seal of the present invention is “lock” and the phase mask 132 is “key”, “lock” and “key”, that is, whether the anti-counterfeit seal of the present invention and the phase mask 132 match or not are determined. Can be used for authentication. In this case, whether or not the authentication is possible can be immediately determined at the stage of recognizing whether or not the forgery prevention seal of the present invention matches the phase mask 132.
Further, if a forgery prevention seal in which a plurality of holograms are stacked is used, the level of safety can be increased.
[0075]
[Eighth Embodiment]
The waveguide hologram type forgery prevention seal according to the eighth embodiment of the present invention uses a forgery prevention seal substantially equivalent to the forgery prevention seal of the fifth embodiment. However, the material of the core is different.
[0076]
The article provided with the forgery prevention seal uses a 0.2 mm thick ARTON resin sheet as the transparent cover seal 73 shown in FIG. The adherend 71 is paper.
All of the bonding parts 74 to 76 use a two-part mixed type epoxy adhesive. Also, by using a fluorine-added ultraviolet curable resin for the core 82, the adhesive strength between the core 82 and the clads 81 and 83 is reduced.
[0077]
As described above, each embodiment of the present invention has been described. However, the present invention is not necessarily limited to the above-described embodiment, and a range that achieves an object of the present invention and has an effect of the present invention. Within this, it is possible to change and implement as appropriate.
[0078]
【The invention's effect】
As explained above,According to the article provided with the waveguide hologram type forgery prevention seal of the present invention, the adhesive strength between the adherend and the forgery prevention seal, the adhesive strength between the forgery prevention seal and the transparent seal, and the transparent seal and the Since the adhesive strength between the adhesive and the adhesive is larger than the adhesive strength between the core and the clad of the optical waveguide, it can be easily pasted, and even if it is peeled, it cannot be returned to the original state. , Can never be used again. If this is applied to a product package or the like, it is possible to prove that the product package or the like has not been opened.
[0082]
As described above, according to the present invention, conventionally, (1) it is extremely difficult to forge, (2) a legitimate manufacturer can manufacture it at low cost, and (3) discrimination of authenticity. (4) Easy to apply, but difficult to peel off, (5) Even if it could be peeled off, it would not be usable again once it was peeled off, (6) A waveguide hologram-type forgery-preventing seal for preventing counterfeiting and authenticating the legitimacy of a carrier, and an article provided with the same, which can satisfy the requirement that the security level can be changed, etc. An authentication method can be provided.
[Brief description of the drawings]
FIG. 1 is a diagram showing a waveguide hologram type forgery prevention seal according to a first embodiment of the present invention, where (a) is a side view, (b) is a top view, and (c) is an enlarged view of an input section. It is a partially expanded sectional view.
FIGS. 2A and 2B are cross-sectional views showing a waveguide hologram type forgery prevention seal according to a second embodiment of the present invention, wherein FIG. 2A shows a case where input light is not coupled to the waveguide, and FIG. This is the case where it is bonded to a waveguide.
FIGS. 3A and 3B are cross-sectional views illustrating a waveguide hologram type forgery prevention seal according to a third embodiment of the present invention. FIG. 3A illustrates a case where input light is not coupled to a waveguide, and FIG. This is the case where it is bonded to a waveguide.
FIG. 4 is a partial sectional view showing an article provided with a waveguide hologram type forgery prevention seal according to a fourth embodiment of the present invention.
5A and 5B are views showing a waveguide hologram type forgery prevention seal according to a fifth embodiment of the present invention, wherein FIG. 5A is a top view and FIG. 5B is a side view.
FIGS. 6A and 6B are views showing a waveguide hologram type forgery prevention seal according to a sixth embodiment of the present invention, wherein FIG. 6A is a top view and FIG. 6B is a side view.
FIG. 7 is a schematic view showing various examples of a phase modulation pattern of a waveguide hologram type forgery prevention seal according to a seventh embodiment of the present invention.
8A and 8B are configuration diagrams showing an input optical system applied to a waveguide hologram type forgery prevention seal according to a seventh embodiment of the present invention, wherein FIG. 8A is an optical system of a real phase pattern system, and FIG. ) Is a Fourier phase pattern type optical system.
FIG. 9 is a sectional view showing a reproduction-only multiplex hologram card.
[Explanation of symbols]
1 Reproduction-only multiplex hologram card
2-1 to 2-n clad
3-1 to 3-n-1 core
4 Reflective surface
5 Laser light
6 convex lens
7 Guided light
8 scattering factors
9 Diffracted light
10 Hologram image
11 Input section
12 Output unit
13 Clad
14 core
15 Cladding
16 grating
21 External light
22 Guided light
23 Diffracted light
31, 33, 36, 38 cladding
32, 37 cores
34, 39 unevenness
35, 40 uniform grating
41 Plane wave input light
42 Modulated input light
43 Pre-phase modulated input light
44 Input light converted to plane wave
45 Guided light
51, 53, 56, 58 cladding
52, 57 core
54, 59 Inverted grating
61, 62 Plane wave input light
63, 64 Pre-phase modulated input light
65 Guided light
71 Adherend
72 Waveguide hologram type forgery prevention seal
73 Transparent cover seal (transparent seal)
74-76 adhesive
81, 83 clad
82 core
91 Input section
92 Output unit
93 polycarbonate sheet
94, 96 clad
95 core
97 Semiconductor Laser
98 convex lens
99 Guided light
100 diffracted light
101 vibration
Input part for 111 680nm
Input unit for 112 532nm
113 Output unit
114, 116, 118 cladding
115 532nm core
117 680nm core
121 680nm semiconductor laser
122 Optical fiber output end
123 convex lens
124, 125 vibration

Claims (1)

Holograms are formed at a plurality of locations of the single mode planar optical waveguide,
At least one of these holograms is an external light coupling hologram that couples external light incident into the optical waveguide from the outside into the optical waveguide to form guided light, and at least one other hologram is used as the hologram. Diffracted light obtained by diffracting the guided light is a hologram for diffracted light imaging for forming an image outside the optical waveguide,
An article provided with a waveguide hologram type forgery prevention seal, wherein a plurality of the optical waveguides are laminated, and the period of the grating of the external optical coupling hologram is different depending on the layer.
The forgery prevention seal is adhered on the adherend, and a transparent seal is adhered so as to cover at least the forgery prevention seal,
The adhesive strength between the adherend and the anti-counterfeit seal, the adhesive strength between the anti-counterfeit seal and the transparent seal, and the adhesive strength between the transparent seal and the adherent are determined by the light guide. An article with a waveguide hologram-type forgery-preventive seal, wherein the article has greater adhesive strength between the core and the cladding of the waveguide.

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