JP3651913B2 - Phosphor, latent image forming member using the same, and optical reading system - Google Patents

Description

この表から明らかなように、基板２７の反射率が２０％未満であると出力電圧が十分にとれず、しかもＳ／Ｎが小さく、そのために正確な情報の読み取りができない。これに対して基板２７の反射率が２０％以上、好ましくは５０％以上になると出力電圧ならびにＳ／Ｎが高く、正確な情報の読み取りができる。
【００４６】
図８は印刷層２９の膜厚と出力電圧との関係を示す特性図で、横軸に印刷層
２９の膜厚を、縦軸に印刷層２９の励起による出力電圧を示している。
【００４７】
図中のＡは前述のように白色顔料を含有した基板２７の表面に印刷層２９を形成した場合の膜厚と出力電圧との関係を示す特性曲線、直線Ｂは印刷層２９の出力が、前記顔料を含有した基材（可視光領域での平均光反射率８０％）のみの出力電圧の１．６倍となる出力レベルを示した線である。
【００４８】
本発明者らの種々の実験の結果、印刷層２９の出力電圧が直線Ｂよりも低いと、印刷層２９の情報を十分に読み取ることができないから、印刷層２９の出力電圧はこの出力電圧の１．６倍（直線Ｂ）以上必要であり、そのときの印刷層２９の最小厚みがこの図から明らかなように０．５μｍである。印刷層２９の厚みが増えるに従って出力電圧は増大するが、５０μｍになるとほぼ一定する。
【００４９】
印刷層２９の厚みが５０μｍを越えると、光の反射の具合で潜像の印刷層２９があることが分かってしまうので、印刷層２９の厚みは０．５〜５０μｍの範囲に規制する方がよい。
【００５０】
図示していないが印刷層２９を形成したカード基板２７の全面に印刷層２９（バーコードパターン２８）を覆うように隠蔽層を形成すると、印刷層２９の存在を隠すことができる。
【００５１】
前記印刷層２９ならびに隠蔽層は、例えば熱転写，インクジェット，オフセット印刷，スクリーン印刷あるいはグラビア印刷などで作ることができる。そのなかでも特にインクリボンを使用して、熱転写により印刷層２９と隠蔽層を順次形成する方法は、高濃度の蛍光体微粒子を含有した印刷が可能で、しかも所望の厚さの層が確実に得られるなどの理由から賞用できる。
【００５２】
図９は、前記発光素子９からの発光のタイミングならびに受光素子１０の出力状態を示すタイミングチャートである。
【００５３】
同図の（ａ）に示すように発光素子９は、点灯時間Ｔ₁ および消灯時間Ｔ₂ が共に５００μｓｅｃの略等しい時間間隔でオン、オフ動作し印刷層２９に対して間欠的に赤外線を照射するようになっている。図中のＳ₁ は、発光素子９の点灯信号を示している。
【００５４】
同図の（ｂ），（ｃ）はバーコードパターン２８（印刷層２９）を検出した場合の受光素子１０の出力状態を示す図で、発光素子９からの赤外線でバーコードパターン２８中の蛍光体微粒子を励起する。そのため同図（ｂ）に示すように発光素子９の点灯が終了するまで出力が増大する。そして発光素子９からの照射を停止しても、バーコードパターン２８から放出される残光を受光素子１０が検出する。この残光は時間とともに減少するため、予め基準値Ｖｓを設定しておき、この基準値Ｖｓと比較することにより、発光素子９が消灯した直後に矩形信号Ｓ₃ が得られる。
【００５５】
従って、微小時間毎に発光素子９の点灯、消灯を繰り返すことによりバーコードパターン２８のバーコード情報を光学的に読み取ることができる。
【００５６】
このように蛍光体の残光を検出する方法では、蛍光体を光学的に読み取る際には発光素子は消灯しているから反射光がなく、そのため高価な光学フィルタを使用しなくても蛍光を検出することができ、小型でかつ低価格の光学読取システムを提供することができる。
【００５７】
同図（ｃ）は蛍光体の残光を検出する方法を示したが、発光素子の発光中心波長領域（９２０〜９６０ｎｍ）の光を遮断して蛍光体の発光中心波長領域（１４００〜１６０ｎｍ）の光を通過するフィルタを使用すれば、発光素子がオンしている時の蛍光体からの光を検出することができる。同図の（ｄ）は、そのときの受光素子１０の出力状態を示している。
【００５８】
前記実施例ではバーコードを付した場合について説明したが、本発明はこれには限定されるものではなく、例えば数字、記号、特殊形状のマークなど他のマークの読み取りも可能である。
【００５９】
前記実施例ではカードを使用した場合について説明したが、本発明はこれに限定されるものではなく、例えばシート状、袋状、伝票状など他の形態の情報記録媒体の読み取りも可能である。
【００６０】
本発明の光学読取システムは、次のような用途ならびに特徴も有している。
【００６１】
１．ファクトリーオートメーション（ＦＡ）関係
自動車などの組み立て時の管理、すなわち車種別、輸出先国別、製造年月日、製造ロット別などを見えない潜像マークを用いて、外観を損ねることなく管理できる。
【００６２】
２．従来の反射型のバーコードでは読み取れなかった、例えばタイヤなどのような黒いもの、あるいはガラスやプラスチックなどの透明なものへマーキングしても、そのマークの読み取りが可能である。
【００６３】
３．潜像マークの上に文字やデザインを印刷しても潜像マークを読み取ることができるから、商品の値札や商品タグなど小さいスペースが有効に利用できる。
【００６４】
４．前記１．ならびに３．と同じ理由から、化粧品や薬などデザインを重視する商品、あるいは高級感が要求される各種の化粧箱やバッケージに有効である。
【００６５】
５．工場や現場などでは油やホコリで汚れるため従来の反射型のバーコードでは使用できなかった環境下においても、潜像マークでは読み取りが可能である。
【００６６】
６．前記１．ならびに３．と同じ理由から、顧客への納品伝票（通常、納品伝票は顧客の指定する用紙、フォーマットで顧客が必要な情報しか入っていない）に隠しコードとしてメーカ側の管理情報を入れることがてきる。
【００６７】
７．カード状のものに隠しコードとして情報を入れ、ゲームカード（バーコードゲーム）として使用可能である。
【００６８】
８．前記１．ならびに３．と同じ理由から、書籍の管理、図書の管理、図面の管理などに用いれば、デザインを損なうことがない。
【００６９】
９．偽造、変造、改ざんが極めて困難であるから、入退室管理、出退勤管理、ホテルのキーカードなどに適用できる。
【００７０】
１０．有価証券や株券などの偽造、変造、改ざんが防止できる。
【００７１】
１１．クレジットカード、キャッシュカード、テレホンカードなどの偽造、変造、改ざんが防止できる。
【００７２】
１２．学生証、ＩＤカードなどの偽造、変造、改ざんが防止できるとともに、小型化、省スペース化が可能である。
【００７３】
１３．スタンプカード、ポイントカードなどの偽造、変造、改ざんが防止できるとともに、小型化、省スペース化が可能である。
【００７４】
１４．馬券、車券などのギヤンブル投票券の偽造、変造、改ざんが防止できる。
【００７５】
１５．パチンコの景品交換システムに導入して、偽造、変造、改ざんが防止できる。
【００７６】
【発明の効果】
本発明で使用される前記一般式の含酸素酸塩化合物は、従来公知のＬｉＮｄＰ₄ Ｏ₁₂の発光スペクトルとは異なった新規の発光スペクトルを有しているから、偽造防止用などに顕著な効果がある。
【００７７】
【図面の簡単な説明】
【図１】本発明の実施例に係る光学読取装置を備えたバーコードリーダの平面図である。
【図２】本発明の実施例に係る光学読取装置の読取ヘッドの分解斜視図である。
【図３】図２のＸ−Ｘ方向の断面図である。
【図４】図２のＹ−Ｙ方向の断面図である。
【図５】本発明の実施例で使用されるカードの平面図である。
【図６】そのカードの要部拡大断面図である。
【図７】本発明の各実施例における仕込み原料の割合と、製造された蛍光体の組成を示す図である。
【図８】前記カードの印刷層の膜厚と出力電圧との関係を示す特性図である。
【図９】本発明の実施例に係る光学読取装置の発光素子、受光素子のタイミングチャートである。
【図１０】蛍光体ＬｉＮｄＰ₄ Ｏ₁₂の発光スペクトル図である。
【図１１】半導体レーザダイオードの発光スペクトル図である。
【図１２】受光素子で受光した光のスペクトル図である。
【図１３】本発明の比較例１によって製造された蛍光体の発光スペクトル図である。
【符号の説明】
１ 装置本体
２ 読取ヘッド
４ カード
９ 発光素子
１０ 受光素子
１２ バーコードパターン
２７ カード基板
２８ バーコードパターン
２９ 印刷層[0001]
[Industrial application fields]
The present invention relates to a phosphor that is excited by infrared irradiation and emits light in an infrared wavelength region, a latent image forming member using the phosphor, and an optical reading system.
[0002]
[Prior art]
In recent years, bar code has been actively managed in various industries, mainly in the distribution industry, and bar codes have been printed on various prepaid cards or traffic cards. This bar code is used to read a predetermined processing operation.
[0003]
Recently, credit cards and prepaid cards have been used as payment methods in place of cash, and various methods have been proposed to determine whether these cards have been forged or forged. ing.
[0004]
As one example, a mark such as a barcode is printed with ink containing a phosphor to form a latent image mark, and the latent image mark is irradiated with a semiconductor laser to excite the phosphor, and light emitted from the phosphor. An optical reader for reading bar code information by receiving light is proposed.
[0005]
FIG. 10 shows an emission spectrum (spectrum a) of LiNdP ₄ O ₁₂ used as a phosphor, FIG. 11 shows an emission spectrum (spectrum b) of a semiconductor laser diode having a center wavelength λp of 810 nm, and FIG. It is the spectrum of light. A spectrum b in FIG. 12 is the reflected light of the laser output from the semiconductor laser diode and is the same as the emission spectrum (spectrum b) in FIG. A dotted line (c) in FIG. 12 is a cutoff characteristic curve of an optical filter attached in the vicinity of the light receiving surface of the light receiving element in order to separate the spectrum a and the spectrum b.
[0006]
As described above, since the wavelengths of the emission spectrum of the phosphor (spectrum a) and the emission spectrum of the semiconductor laser diode (spectrum b) are considerably separated, if an optical filter having the cutoff characteristic of (c) is used, While irradiating the phosphor mark with the output laser, the reflected light of the laser is blocked by the optical filter, and the phosphor mark can be detected by transmitting only the fluorescence and receiving it with the light receiving element.
[0007]
[Problems to be solved by the invention]
However, since the phosphor having Nd as the emission center used as the phosphor is a known material, there is a disadvantage that the effect used for preventing counterfeiting is weak.
[0008]
An object of the present invention is to provide a novel phosphor, a latent image forming member using the same, and an optical reading system, which have solved the drawbacks of the prior art.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the first invention provides:
Phosphor is characterized in that consisting of _Er 0.2 _Yb 0.2 _Y 0.6 PO ₄ oxygen periodate chloride compound representable by the general formula, such as.
Formula _{Er x Yb s B 1-x} -s P y O z
However, B in the formula is at least one element s selected from the group of Y, La, Gd, Bi, Ce, Lu, In, and a numerical value x in the range of 0.01 to 0.99 is 0.01 to The numerical value y in the range of 0.99 is 1.
z is 4
[0010]
In order to achieve the above object, the second invention provides:
In the latent image forming member, for example, phosphor fine powder of an oxygenate compound represented by the following general formula such as Er _0.2 Yb _0.2 Y _0.6 PO _4, and wax, vinyl chloride-acetic acid, for example The present invention is characterized in that an infrared-excitable printing layer comprising a binder that transmits infrared rays such as a vinyl copolymer is formed on a substrate.
Formula _{Er x Yb s B 1-x} -s P y O z
However, B in the formula is at least one element s selected from the group of Y, La, Gd, Bi, Ce, Lu, In, and a numerical value x in the range of 0.01 to 0.99 is 0.01 to The numerical value y in the range of 0.99 is 1.
z is 4
[0011]
In order to achieve the above object, the third invention provides:
In the optical reading system, for example, an oxygenate compound represented by the following general formula such as Er _0.2 Yb _0.2 Y _0.6 PO ₄ is used as a phosphor.
The emission center wavelength of the light emitting element that excites the phosphor is in the range of 900 to 1000 nm.
The wavelength range in which the light receiving element that receives light from the phosphor can receive light is in the range of 1400 to 1600 nm,
The phosphor is excited by infrared rays from the light emitting element, and light from the phosphor is detected by the light receiving element.
Formula _{Er x Yb s B 1-x} -s P y O z
However, B in the formula is at least one element s selected from the group of Y, La, Gd, Bi, Ce, Lu, In, and a numerical value x in the range of 0.01 to 0.99 is 0.01 to The numerical value y in the range of 0.99 is 1.
z is 4
[0012]
[Action]
The oxygen-containing acid salt compound of the above general formula used in the present invention has a novel emission spectrum different from the emission spectrum having Nd as the emission center, so that it is remarkable for anti-counterfeiting. effective.
[0013]
【Example】
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of an optical reading apparatus (barcode reader) according to the present embodiment, FIG. 2 is an exploded perspective view of a main part of the reading head in the optical reading apparatus, and FIG. 3 is an XX of FIG. FIG. 4 is a sectional view of the read head in the YY direction of FIG.
[0014]
As shown in FIG. 1, an optical reader (barcode reader) includes an apparatus main body 1, a read head 2 mounted in the apparatus main body 1, and elements connected to the read head 2 to perform various controls as will be described later. And a printed circuit board 3 on which is mounted.
[0015]
As shown in the figure, a guide groove 5 through which the card 4 is inserted is formed on the upper surface of the apparatus main body 1, and the read head 2 is attached so as to face the inner wall surface of the guide groove 5.
[0016]
A card 4 having a barcode pattern, which will be described later, is manually inserted along the guide groove 5 in the direction of the arrow, and information on the barcode pattern is optically read by the reading head 2 during that time.
[0017]
As shown in FIG. 2, the reading head 2 includes a head body 6 that also serves as a case, a slit sheet 7 that is inserted into the head body 6, a sheet pressing member 8 that also serves as an element holder, and the sheet. The light-emitting element 9 and the light-receiving element 10 held by the pressing member 8 and a head cover 11 that closes the upper surface opening of the head body 6 are configured.
[0018]
An opening 13 parallel to the longitudinal direction of the barcode pattern 28 (see FIG. 5) formed on the card 4 is formed in the center of the lower surface of the head body 6, and the both sides of the lower surface are connected as shown in FIG. A stepped portion 14 is provided.
[0019]
Inside the head body 6, sheet receiving surfaces 15, 15 inclined from both sides toward the opening 13 are formed, and pins 16 (see FIG. 2) are erected in the middle of the sheet receiving surfaces 15, 15. A locking groove 17 (see FIG. 2) is provided at both ends of the opening 13.
[0020]
As shown in FIGS. 2 and 3, flange portions 18 and 18 for attaching the reading head 2 to the apparatus main body 1 are provided in the vicinity of the upper surface opening of the head main body 6.
[0021]
As shown in FIG. 2, the slit sheet 7 is a black printing layer on a base film made of a transparent synthetic resin film such as polyethylene terephthalate (PET) except for the slit-like translucent portion 19 (see FIG. 2). It is comprised from the flexible sheet | seat in which 20 was formed. Holes 21 are provided in the front and rear of the slit sheet 7, and the slits 7 are positioned on the head body 6 by inserting the pins 16 of the head body 6 into the holes 21, respectively, as shown in FIG. As described above, the slit-like light transmitting portion 19 of the slit sheet 7 is disposed in the center of the opening 13 of the head body 6.
[0022]
In this embodiment, the slit sheet 7 in which the printing layer 20 is formed on the transparent base film is used. However, for example, a slit sheet in which slit-like grooves are formed on a thin metal plate such as stainless steel can also be used.
[0023]
2 and 3, the lower surface of the sheet pressing member 8 is bent along the sheet receiving surface 15 of the head main body 6. The lower surface of the sheet pressing member 8 and the sheet receiving member of the head main body 6 are bent. The slit sheet 7 is mechanically sandwiched between the surface 15 and the translucent part 19 of the slit sheet 7 is pushed into the opening 13 of the head body 6. A slit-shaped light restricting hole 22 is formed at the center of the sheet pressing member 8 and faces the light transmitting portion 19 as shown in FIG.
[0024]
Locking pieces 23 and 23 (see FIG. 2) having a T-shape in plan view are integrally provided on both sides of the sheet pressing member 8, and the locking pieces 23 and 23 are formed as locking grooves in the head body 6. The sheet pressing member 8 is attached in the head body 6 by being fitted into the pins 17 and 17.
[0025]
A holding wall 24 having a partially arc shape is erected on the upper portion of the sheet pressing member 8, and the tip portions of the light emitting element 9 and the light receiving element 10 are inserted and held in the holding wall 24 as shown in FIG. 4. .
[0026]
The light emitting element 9 has a center wavelength for emitting infrared rays including near infrared rays of 920 to 920.
A light emitting diode having a center wavelength of 940 nm is used in the embodiment.
[0027]
As the light receiving element 10, a light receiving element made of Ge, In—Ga—As, PbS, or PbSe that can detect the light emission wavelength region of 1400 to 1600 nm is used.
[0028]
Four engaging claws 25 are provided around the head cover 11 so as to protrude downward. The engaging claws 25 are engaged with the engaging step portions 14 of the head body 6 as shown in FIG. As a result, the assembly of the read head 2 is completed.
[0029]
As shown in FIG. 3, a leg portion 26 projects downward from the inner surface of the head cover 11. When the head cover 11 is assembled as shown in FIG. The sheet pressing member 8 is pressed to the sheet receiving surface 15 side through the element 10, and the slit sheet 7 is securely fixed.
[0030]
Next, the configuration of the card 4 will be described with reference to FIGS. This card 4 is used as, for example, various prepaid cards, telephone cards, and traffic cards.
[0031]
FIG. 5 is a plan view of the card, and FIG. 6 is an enlarged cross-sectional view of the main part of the card.
[0032]
As shown in FIG. 5, a printed layer 29 (see FIG. 5) having a latent image barcode pattern 28 is formed on the surface of the card substrate 27. The card substrate 27 is made of, for example, a vinyl chloride sheet in which a white pigment such as titanium oxide is dispersed and held, and has a property of reflecting infrared rays.
[0033]
On the printing layer 29, a desired barcode pattern 28 is printed with ink composed of phosphor fine particles that are excited by infrared irradiation and a transparent (infrared transparent) binder that disperses and holds the phosphor fine particles.
[0034]
The phosphor is a phosphate compound represented by the following general formula, and this phosphor is excellent in chemical resistance.
Formula _{Er x Yb s B 1-x} -s P y O z
However, B in the formula is at least one element s selected from the group of Y, La, Gd, Bi, Ce, Lu, In, and a numerical value x in the range of 0.01 to 0.99 is 0.01 to The numerical value y in the range of 0.99 is 1.
z is 4
[0037]
FIG. 7 shows the ratio of the raw materials in the specific production example of the phosphor fine particles, the ratio of the raw materials in the specific production example of the phosphor fine particles according to the comparative example, and the phosphor composition produced thereby.
[0038]
In FIG. 7, Examples and Comparative Examples 1, 2, 3, and 4 were fired at 700 ° C. for 2 hours, then treated with hot water, further treated with nitric acid (1 mol), and then washed with water to obtain a phosphor. It was.
[0039]
In Comparative Examples 5, 6, and 7, phosphors were obtained in the same manner as in Example 1 except that baking was performed at 1200 ° C. for 20 hours.
[0040]
The emission spectrum of the phosphor (KYb _0.9 Er _0.1 P ₄ O ₁₂ ) obtained in Comparative Example 1 is shown in FIG. In addition, the dotted line in a figure is a spectrum of light emitting LED. As can be seen from this figure, the 940 nm LED emits light having a peak at 1580 nm, so that it cannot be read by an existing Nd detection system.
[0041]
The content of the phosphor fine particles is suitably 50 to 80% by weight, and in this example, 75% by weight. When the content of the phosphor fine particles is less than 50% by weight, the output from the printing layer 29 is weak. On the other hand, when the content of the phosphor fine particles exceeds 80% by weight, the printability of the print layer 29 (barcode pattern) is reduced. It may worsen and cause printing defects.
[0042]
As the binder, for example, wax, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate copolymer, polyester, polyurethane, carbonate or the like may be used alone or as a mixture. In addition, a plasticizer, surfactant, etc. are added suitably as needed.
[0043]
The phosphor fine particles are excited by infrared rays to emit light. In order to effectively excite the phosphor fine particles, the reflectance of the substrate 27 is set to 20% or more. That is, by providing the substrate 27 with a high reflectance, infrared rays are reflected on the surface of the substrate 27 to promote excitation of the phosphor fine particles. As described above, by dispersing and holding a white pigment such as titanium oxide in the substrate 27, the reflectance of the substrate 27 can be increased. In this embodiment, the substrate 27 having a reflectance of 80% is used. Yes.
[0044]
The following table is a table showing the results of measuring the output voltage and S / N of the printed layer 29 when the white pigment content is adjusted to change the light reflectance of the substrate 27 in various ways.
[0045]

As is apparent from this table, when the reflectance of the substrate 27 is less than 20%, the output voltage cannot be sufficiently obtained, and the S / N is small, so that accurate information cannot be read. On the other hand, when the reflectance of the substrate 27 is 20% or more, preferably 50% or more, the output voltage and S / N are high, and accurate information can be read.
[0046]
FIG. 8 is a characteristic diagram showing the relationship between the film thickness of the printing layer 29 and the output voltage. The horizontal axis shows the film thickness of the printing layer 29 and the vertical axis shows the output voltage due to the excitation of the printing layer 29.
[0047]
A in the figure is a characteristic curve showing the relationship between the film thickness and the output voltage when the printed layer 29 is formed on the surface of the substrate 27 containing the white pigment as described above, and the straight line B is the output of the printed layer 29. It is the line which showed the output level used as 1.6 times the output voltage of only the base material (average light reflectivity 80% in visible region) containing the said pigment.
[0048]
As a result of various experiments by the present inventors, if the output voltage of the print layer 29 is lower than the straight line B, the information of the print layer 29 cannot be read sufficiently. 1.6 times (straight line B) or more is necessary, and the minimum thickness of the printed layer 29 at that time is 0.5 μm as is apparent from this drawing. The output voltage increases as the thickness of the printing layer 29 increases, but becomes almost constant when the thickness is 50 μm.
[0049]
If the thickness of the print layer 29 exceeds 50 μm, it will be understood that there is a latent image print layer 29 due to the reflection of light, so the thickness of the print layer 29 should be regulated to a range of 0.5 to 50 μm. Good.
[0050]
Although not shown, if a concealing layer is formed on the entire surface of the card substrate 27 on which the printing layer 29 is formed so as to cover the printing layer 29 (barcode pattern 28), the presence of the printing layer 29 can be hidden.
[0051]
The printing layer 29 and the concealing layer can be made by, for example, thermal transfer, ink jet, offset printing, screen printing, or gravure printing. In particular, the method of sequentially forming the printing layer 29 and the concealing layer by thermal transfer using an ink ribbon enables printing containing high-concentration phosphor fine particles, and ensures that a layer having a desired thickness is obtained. Can be used for reasons such as being obtained.
[0052]
FIG. 9 is a timing chart showing the timing of light emission from the light emitting element 9 and the output state of the light receiving element 10.
[0053]
As shown in FIG. 5A, the light-emitting element 9 is turned on and off at substantially equal time intervals of 500 μsec for both the lighting time T ₁ and the light-off time T ₂ and intermittently irradiates the print layer 29 with infrared rays. It is supposed to be. S ₁ in the figure indicates a lighting signal of the light emitting element 9.
[0054]
(B) and (c) of the same figure are diagrams showing the output state of the light receiving element 10 when the barcode pattern 28 (printing layer 29) is detected. Fluorescence in the barcode pattern 28 is emitted by infrared rays from the light emitting element 9. Excites body particles. Therefore, the output increases until the lighting of the light emitting element 9 is finished as shown in FIG. Even if the irradiation from the light emitting element 9 is stopped, the light receiving element 10 detects the afterglow emitted from the barcode pattern 28. Therefore afterglow decreases with time, set in advance a reference value Vs, by comparison with the reference value Vs, the rectangular signal S ₃ is obtained immediately after the light emitting element 9 is turned off.
[0055]
Therefore, the bar code information of the bar code pattern 28 can be optically read by repeatedly turning on and off the light emitting element 9 every minute time.
[0056]
In this way, in the method of detecting the afterglow of the phosphor, when the phosphor is optically read, the light emitting element is extinguished, so there is no reflected light, and therefore fluorescence can be obtained without using an expensive optical filter. It is possible to provide a small-sized and low-cost optical reading system.
[0057]
FIG. 3C shows a method for detecting the afterglow of the phosphor, but the light in the emission center wavelength region (920 to 960 nm) of the light emitting element is blocked to emit the emission center wavelength region (1400 to 160 nm) of the phosphor. If a filter that passes this light is used, the light from the phosphor when the light emitting element is on can be detected. FIG. 4D shows the output state of the light receiving element 10 at that time.
[0058]
In the above-described embodiment, the case where a bar code is attached has been described. However, the present invention is not limited to this, and other marks such as numerals, symbols, and specially shaped marks can be read.
[0059]
In the above embodiment, the case where a card is used has been described. However, the present invention is not limited to this, and it is possible to read information recording media in other forms such as a sheet, a bag, and a slip.
[0060]
The optical reading system of the present invention has the following uses and characteristics.
[0061]
1. Factory automation (FA) -related management at the time of assembly, such as vehicle type, country of export destination, date of manufacture, production lot, etc., can be managed without losing appearance by using latent image marks.
[0062]
2. For example, even if marking is performed on a black object such as a tire or a transparent object such as glass or plastic, which cannot be read with a conventional reflective barcode, the mark can be read.
[0063]
3. Since the latent image mark can be read even if characters or designs are printed on the latent image mark, a small space such as a product price tag or a product tag can be used effectively.
[0064]
4). 1 above. And 3. For the same reason as above, it is effective for products such as cosmetics and medicines that emphasize design, or for various types of cosmetic boxes and packages that require a high-class feel.
[0065]
5. The latent image mark can be read even in an environment that cannot be used with a conventional reflective barcode because it is soiled with oil or dust in factories or on-site.
[0066]
6). 1 above. And 3. For the same reason, the management information of the manufacturer can be put as a hidden code on the delivery slip to the customer (usually the delivery slip contains only the information required by the customer in the form and format specified by the customer).
[0067]
7. It can be used as a game card (barcode game) by putting information as a hidden code in a card-like object.
[0068]
8). 1 above. And 3. For the same reason, if used for book management, book management, drawing management, etc., the design is not impaired.
[0069]
9. Forgery, alteration, and alteration are extremely difficult, and can be applied to entrance / exit management, attendance / exit management, hotel key cards, etc.
[0070]
10. Forgery, alteration, and alteration of securities and stock certificates can be prevented.
[0071]
11. Forgery, alteration, and alteration of credit cards, cash cards, telephone cards, etc. can be prevented.
[0072]
12 Forgery, alteration, and alteration of student ID cards and ID cards can be prevented, and miniaturization and space saving are possible.
[0073]
13. Forgery, alteration, and alteration of stamp cards and point cards can be prevented, and miniaturization and space saving are possible.
[0074]
14 Forgery, alteration, and alteration of gambling voting tickets such as betting tickets and car tickets can be prevented.
[0075]
15. It can be introduced into a pachinko prize exchange system to prevent counterfeiting, alteration and tampering.
[0076]
【The invention's effect】
The oxygen-containing acid salt compound of the above general formula used in the present invention has a novel emission spectrum different from the emission spectrum of the conventionally known LiNdP ₄ O ₁₂ , so that it is remarkable for anti-counterfeiting etc. There is.
[0077]
[Brief description of the drawings]
FIG. 1 is a plan view of a bar code reader including an optical reading device according to an embodiment of the present invention.
FIG. 2 is an exploded perspective view of a reading head of the optical reading apparatus according to the embodiment of the present invention.
FIG. 3 is a cross-sectional view in the XX direction of FIG.
4 is a cross-sectional view in the YY direction of FIG. 2;
FIG. 5 is a plan view of a card used in an embodiment of the present invention.
FIG. 6 is an enlarged cross-sectional view of the main part of the card.
FIG. 7 is a diagram showing the ratio of charged raw materials and the composition of the produced phosphor in each example of the present invention.
FIG. 8 is a characteristic diagram showing the relationship between the printed layer thickness of the card and the output voltage.
FIG. 9 is a timing chart of a light emitting element and a light receiving element of the optical reading apparatus according to the embodiment of the present invention.
FIG. 10 is an emission spectrum diagram of phosphor LiNdP ₄ O ₁₂ .
FIG. 11 is an emission spectrum diagram of a semiconductor laser diode.
FIG. 12 is a spectrum diagram of light received by a light receiving element.
FIG. 13 is an emission spectrum diagram of a phosphor manufactured according to Comparative Example 1 of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Apparatus main body 2 Reading head 4 Card 9 Light emitting element 10 Light receiving element 12 Bar code pattern 27 Card board 28 Bar code pattern 29 Printing layer

Claims (3)

Phosphor which is a oxygen-periodate chloride compound representable by the following formula.
Formula _{Er x Yb s B 1-x} -s P y O z
However, B in the formula is at least one element s selected from the group of Y, La, Gd, Bi, Ce, Lu, In, and a numerical value x in the range of 0.01 to 0.99 is 0.01 to The numerical value y in the range of 0.99 is 1.
z is 4 A latent image forming member comprising an infrared excitable print layer comprising a phosphor fine powder of an oxygenate compound represented by the following general formula and a binder that transmits infrared rays on a substrate.
Formula _{Er x Yb s B 1-x} -s P y O z
However, B in the formula is at least one element s selected from the group of Y, La, Gd, Bi, Ce, Lu, In, and a numerical value x in the range of 0.01 to 0.99 is 0.01 to The numerical value y in the range of 0.99 is 1.
z is 4 Using an oxygenate compound represented by the following general formula as a phosphor,
The emission center wavelength of the light emitting element that excites the phosphor is in the range of 900 to 1000 nm.
The wavelength range in which the light receiving element that receives light from the phosphor can receive light is in the range of 1400 to 1600 nm,
An optical reading system, wherein the phosphor is excited by infrared rays from the light emitting element, and light from the phosphor is detected by the light receiving element.
Formula _{Er x Yb s B 1-x} -s P y O z
However, B in the formula is at least one element s selected from the group of Y, La, Gd, Bi, Ce, Lu, In, and a numerical value x in the range of 0.01 to 0.99 is 0.01 to The numerical value y in the range of 0.99 is 1.
z is 4

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