以下，對本發明之實施形態進行說明。本發明之光學玻璃之必須構成為：以玻璃作為主體，且於玻璃中含有結晶。又，本說明書中之光學玻璃之光學特性係設為存在由光學玻璃與空氣之折射率之差異引起之表面反射者。 本發明之光學玻璃可較佳地用作固體攝像裝置中之近紅外線截止濾波器玻璃。近紅外線截止濾波器玻璃係於固態攝像裝置中配置於成像光學系統(透鏡群)與固態攝像元件(感測器)之間、或者配置於成像光學系統之被攝體側(固態攝像元件之相反側)。 本發明之光學玻璃具備使可視範圍之光透過且吸收紫外線及紅外線之光學特性。並且，本發明之光學玻璃係吸收紅外線及紫外線者，且具備於在300 nm～450 nm之波長頻帶下之光之透過率成為50%之波長之前後3 nm之波長範圍算出的波長與透過率之近似直線之斜率為3以上之光學特性。以下，亦有將「於在300 nm～450 nm之波長頻帶下之光之透過率成為50%之波長之前後3 nm之波長範圍算出的波長與透過率之近似直線之斜率」稱為「斜率(S)」之情況。 藉由具備此種光學特性，而能夠確實地截止近紫外線而抑制偽色或耀斑等之產生。又，由於藉由光學玻璃之吸收作用而並非藉由光學多層膜之反射作用來截止近紫外線，故而伴隨光之斜入射之光學特性之變化極小，即便於因固態攝像裝置內之雜散光產生之近紫外線之斜入射光入射至光學玻璃的情形時，亦能夠確實地截止近紫外線。 於光學玻璃中，若斜率(S)未達3，則近紫外線之一部分透過，因此擔憂產生偽色或耀斑等。本發明之光學玻璃係斜率(S)為3以上。斜率(S)較佳為3.5以上，更佳為4以上。又，若斜率(S)超過20，則光學玻璃之玻璃組成之調整極難且製造成本變高，故而欠佳。斜率(S)較佳為20以下，更佳為15以下。 再者，上述所謂於在300 nm～450 nm之波長頻帶下之光之透過率成為50%之波長之前後3 nm之波長之範圍內算出的波長與透過率之近似直線之斜率(斜率(S))，詳細而言係藉由以下之方法而決定。 首先，對光學玻璃之分光透過率進行測定。繼而， 對300 nm～450 nm之波長頻帶下之光之透過率成為50%的波長(整數值)進行特定。此處，於自顯示分光透過率之曲線獲得之波長不成為整數值的情形時，將最接近之整數值視為透過率成為50%之波長。然後，以透過率成為50%之波長(以下，亦有記載為「λ50(300-450)
」之情況)為中心，決定7個自λ50(300-450)
至距離短波長側及長波長側分別為3 nm之波長間的每隔1 nm之透過率資料。例如，於透過率成為50%之波長為380 nm之情形時，決定於377 nm、378 nm、379 nm、380 nm、381 nm、382 nm、383 nm下之波長與透過率之資料(計7個)。然後，根據該7個資料而製作以波長[nm]為X軸、以透過率[%]為Y軸之近似直線，將所獲得之近似直線之斜率[%/nm]設為斜率(S)。 本發明之光學玻璃較佳為波長450 nm～480 nm之光之平均透過率為80%以上。藉由具備此種特性，而於將本發明之光學玻璃用於例如固態攝像裝置之情形時，可視範圍之藍光之透過率較高，可獲得色再現性優異之攝像圖像。再者，先前為了配合藍光之透過率而獲取與可視範圍之其他波長成分之色平衡，而對感測器之感度進行了調整。因此，藉由使用本發明之光學玻璃，可實現最大限度地發揮出感測器原本所具有之受光感度能力之高感度攝像。 再者，上述之平均透過率更佳為81%以上，進而較佳為82%以上。又，若上述之平均透過率超過92%，則光學玻璃之玻璃組成之調整極難且製造成本變高，故而欠佳。上述之平均透過率較佳為92%以下，更佳為91%以下。 本發明之光學玻璃較佳為自600 nm～700 nm之波長頻帶下之光之透過率成為50%的波長(以下，亦有記載為「λ50(600-700)
」之情況)減去300 nm～450 nm之波長頻帶下之光之透過率成為50%的波長(λ50(300-450)
)所得之值、λ50(600-700)
－λ50(300-450)
處於200 nm～300 nm之範圍內。藉由具備此種特性，而可視範圍之光之透過率較高，而可以高感度獲得色再現性優異之攝像圖像。再者，上述之波長間隔(λ50(600-700)
－λ50(300-450)
)較佳為220 nm～290 nm，更佳為230 nm～280 nm。 本發明之光學玻璃較佳為波長700 nm～850 nm之平均吸光係數(以下，亦有記載為「ε(700-850)
」之情況)相對於波長450 nm～480 nm之平均吸光係數(以下，亦有記載為「ε(450 - 480)
」之情況)之比率、ε(700-850)
/ε(450-480)
為33以上。藉由具備此種特性，而於將本發明之光學玻璃用於例如固態攝像裝置之情形時，可一面確實地截止攝像圖像所不需要之近紅外線，一面使可視範圍之藍光之透過率變高，因此可以高感度獲得色再現性優異之攝像圖像。 再者，平均吸光係數之比率(ε(700-850)
/ε(450-480)
)較佳為34以上，更佳為35以上。又，若平均吸光係數之比率(ε(700-850)
/ε(450-480)
)超過80，則光學玻璃之玻璃組成之調整極難且製造成本變高，故而欠佳。平均透過率之比率(ε(700-850)
/ε(450-480)
)較佳為80以下，更佳為70以下。 對於近紅外線截止濾波器玻璃，較理想為兼顧提高波長450 nm～480 nm之光之透過率及降低波長700 nm～850 nm之光之透過率。關於先前之近紅外線截止濾波器玻璃，為了提高波長450 nm～480 nm之光之透過率，有降低玻璃中之Cu濃度之方法，但於該情形時，有波長700 nm～850 nm之光之透過率變高之弊病。又，為了降低波長700 nm～850 nm之光之透過率，有提高Cu濃度之方法，但於該情形時，有波長450 nm～480 nm之光之透過率變低之弊病。即，關於先前之近紅外線截止濾波器玻璃，原本難以兼顧提高波長450 nm～480 nm之光之透過率及降低波長700 nm～850 nm之光之透過率，而必須採用向任一種之特性妥協，或者設為取得了兩者之平衡之特性之任一種方法。 本發明之光學玻璃之詳細內容係於下文進行說明，但關於與波長450 nm～480 nm之光之透過率及波長700 nm～850 nm之光之透過率兩者相關之光學玻璃中的Cu成分，發現如下情況，即藉由將使波長450 nm～480 nm之透過率降低之Cu+
離子以鹵化物之形式於玻璃中作為結晶析出以儘可能地減少非晶質(玻璃)部分中之Cu+
離子之存在量，而可獲得上述之光學特性。 再者，於將Cu+
離子以鹵化物之形式於玻璃中作為結晶析出之情形時，對於使波長700 nm～850 nm之光之透過率降低之非晶質部分之Cu2+
離子的影響幾乎沒有，因此可在維持波長700 nm～850 nm之光之透過率較低之較佳光學特性的狀態下提高波長450 nm～480 nm之光之透過率。又，由於玻璃中作為結晶析出之Cu之鹵化物在紫外線範圍具備陡峭之吸收特性，故而本發明之光學玻璃亦能夠截止攝像圖像所不需要之近紫外線。 本發明之光學玻璃必須含有P及Cu作為陽離子成分，且含有選自Cl、Br及I中之至少1種作為陰離子成分，且上述Cu之含量以陽離子%計為0.5～25%，且該光學玻璃含有結晶。即，本發明之光學玻璃包含玻璃與結晶。玻璃係非晶質成分，且係本發明之光學玻璃之主要成分。又，結晶較佳為玻璃中之含有成分作為結晶析出至玻璃中之結晶。於本說明書中，各成分之含量表示光學玻璃中之含量。又，於以下之說明中，於僅稱為「玻璃」之情形時，意指光學玻璃中之作為非晶質成分之玻璃。 P係形成玻璃之主成分(玻璃形成氧化物)，且係用以提高光學玻璃之近紅外光範圍之截止性之必須成分。P於玻璃中例如以P5+
之形式含有。 又，Cu係用以截止近紅外線之必須成分。Cu於玻璃中例如以Cu2+
、Cu+
之形式含有。若光學玻璃中之Cu之含量未達0.5%，則於使光學玻璃之厚度變薄時未充分地獲得Cu之效果，若超過25%，則可視範圍透過率降低，故而欠佳。Cu之含量較佳為0.5～19%，更佳為0.6～18%，進而較佳為0.7～17%。再者，所謂Cu之含量，係指玻璃中之Cu2+
、Cu+
、及結晶中之Cu成分之合計量。 本發明之光學玻璃含有選自Cl、Br及I中之至少1種作為陰離子成分。Cl、Br及I亦可組合而含有2種以上。Cl、Br及I於玻璃中分別以Cl-
、Br-
、及I-
之形式含有。光學玻璃中之Cl、Br及I之含量以陰離子%之總量計較佳為0.01～20%。若Cl、Br及I之含量未達0.01%，則結晶難以析出，若超過20%，則有揮發性變高而玻璃中之脈理增加之虞，故而欠佳。光學玻璃中之Cl、Br及I之含量以總量計更佳為0.01～15%，進而較佳為0.02～10%。 Cl-
、Br-
、I-
係與玻璃中之Cu+
進行反應，Cl-
係形成CuCl，Br-
係形成CuBr，I-
係形成CuI。藉由該等成分，所獲得之光學玻璃可明顯地截止近紫外光範圍之光。Cl-
、Br-
、I-
可配合欲明顯地截止近紫外光範圍之光之波長而適當地進行選擇。 本發明之光學玻璃所含有之結晶較佳為包含選自CuCl、CuBr及CuI中之至少1種之結晶。即，光學玻璃所含有之CuCl、CuBr、CuI較佳為作為結晶析出。藉由選自CuCl、CuBr及CuI中之至少1種以結晶之狀態析出，而能夠提高紫外光範圍之光之明顯截止性。 本發明之光學玻璃較佳為含有Ag作為陽離子成分。Ag係與選自Cl、Br及I中之至少1種結而析出鹵化銀(例如AgCl)。於該情形時，AgCl係作為結晶核發揮作用，且有容易使CuCl之結晶析出之作用。光學玻璃中之Ag之含量以陽離子%計較佳為0.01～5%。若未達0.01%，則未充分地獲得將結晶析出之作用。又，若超過5%，則形成Ag膠體而可見光之透過率降低，故而欠佳。 又，亦可於光學玻璃中將鹵化銀以外之成為結晶核之成分析出或導入，而使選自CuCl、CuBr及CuI中之至少1種之結晶析出。 本發明之光學玻璃中之結晶成分主要包含選自CuCl、CuBr及CuI中之至少1種，亦可包含Ag與選自Cl、Br及I中之至少1種結合而成之結晶核或其以外之結晶核。 繼而，針對本發明之光學玻璃，以2個實施形態之光學玻璃、即包含磷酸玻璃與結晶之實施形態1之光學玻璃及包含氟磷酸玻璃與結晶之實施形態2之光學玻璃為例進行說明。 本發明之實施形態1之光學玻璃以氧化物基準之質量%表示計含有： P2
O5
：35～75% Al2
O3
：5～15% R2
O：3～30%(其中，R2
O表示Li2
O、Na2
O及K2
O之總量) R'O：3～35%(其中，R'O表示MgO、CaO、SrO、BaO、及ZnO之總量) CuO：0.5～20%。 實施形態1之光學玻璃含有選自Cl、Br及I中之至少1種。實施形態1之光學玻璃中之選自Cl、Br及I中之至少1種的含量及含有形態係如上所示。於以下說明如上述般限定構成本發明之實施形態1之光學玻璃之各成分的含量之原因。於以下之說明中，關於實施形態1之光學玻璃之含有成分之含量「%」，只要沒有特別事先說明，則為氧化物基準之質量%。 P2
O5
係形成玻璃之主成分(玻璃形成氧化物)，且係用以提高光學玻璃之近紅外光範圍之截止性之必須成分，若未達35%，則未充分地獲得P2
O5
之效果，若超過75%，則玻璃變得不穩定，耐候性降低，又光學玻璃中之選自Cl、Br及I中之至少1種之殘存量降低，而未充分地析出結晶，故而欠佳。P2
O5
之含量較佳為38～73%，更佳為40～72%。 Al2
O3
係形成玻璃之主成分(玻璃形成氧化物)，且係用以提高耐候性等之必須成分，若未達5%，則未充分地獲得Al2
O3
之效果，若超過15%，則玻璃變得不穩定，又光學玻璃之近紅外線截止性降低，故而欠佳。Al2
O3
之含量較佳為5.5～12%，更佳為6～10%。 R2
O(其中，R2
O表示Li2
O、Na2
O及K2
O之總量)係用以降低玻璃之熔融溫度、降低玻璃之液相溫度、及使玻璃穩定等之成分，若未達3%，則未充分地獲得R2
O之效果，若超過30%，則玻璃變得不穩定，故而欠佳。R2
O之含量較佳為5～28%，更佳為6～25%。再者，R2
O係指Li2
O、Na2
O及K2
O之總量，即Li2
O＋Na2
O＋K2
O。又，R2
O係選自Li2
O、Na2
O及K2
O中之1種或2種以上，於2種以上之情形時，亦可為任意之組合。 Li2
O係用以降低玻璃之熔融溫度、降低玻璃之液相溫度、及使玻璃穩定等之成分。於含有Li2
O之情形時，若超過15%，則玻璃變得不穩定，故而欠佳。Li2
O之含量較佳為0～10%，更佳為0～8%。 Na2
O係用以降低玻璃之熔融溫度、降低玻璃之液相溫度、及使玻璃穩定等之成分。於含有Na2
O之情形時，若超過25%，則玻璃變得不穩定，故而欠佳。Na2
O之含量較佳為0～22%，更佳為0～20%。 K2
O並非必須成分，但係用以降低玻璃之熔融溫度、降低玻璃之液相溫度等之成分。於含有K2
O之情形時，若超過25%，則玻璃變得不穩定、熱膨脹率顯著地變大，故而欠佳。K2
O之含量較佳為0～20%，更佳為0～15%。 R'O(其中，R'O表示MgO、CaO、SrO、BaO、及ZnO之總量)係用以降低玻璃之熔融溫度、降低玻璃之液相溫度、使玻璃穩定、及提高玻璃之強度等之必須成分。若未達3%，則未充分地獲得R'O之效果，若超過35%，則玻璃變得不穩定、光學玻璃之近紅外線截止性降低、玻璃之強度降低等，故而欠佳。R'O之含量較佳為3.5～32%，更佳為4～30%。再者，R'O係指MgO、CaO、SrO、BaO、及ZnO之總量、即R'O係MgO＋CaO＋SrO＋BaO＋ZnO。又，R'O係選自MgO、CaO、SrO、BaO及ZnO中之1種或2種以上，於2種以上之情形時，亦可為任意之組合。 MgO係用以降低玻璃之熔融溫度、降低玻璃之液相溫度、及提高玻璃之強度等之成分。然而，MgO有使玻璃變得不穩定而變得容易失透之傾向，尤其是於必須較高地設定Cu之含量之情形時，較佳為不含有MgO。於含有MgO之情形時，若超過5%，則玻璃變得極不穩定、光學玻璃之近紅外線截止性降低，故而欠佳。MgO之含量較佳為0～3%，更佳為0～2%。 CaO係用以降低玻璃之熔融溫度、降低玻璃之液相溫度、使玻璃穩定、及提高玻璃之強度等之成分。於含有CaO之情形時，若超過10%，則玻璃變得不穩定而變得容易失透、光學玻璃之近紅外線截止性降低，故而欠佳。CaO之含量較佳為0～7%，更佳為0～5%。 SrO係用以降低玻璃之熔融溫度、降低玻璃之液相溫度、及使玻璃穩定等之成分。於含有SrO之情形時，若超過15%，則玻璃變得不穩定而變得容易失透、光學玻璃之近紅外線截止性降低，故而欠佳。SrO之含量較佳為0～12%，更佳為0～10%。 BaO雖並非必須成分，但係用以降低玻璃之熔融溫度、降低玻璃之液相溫度、及使玻璃穩定等之成分。於含有BaO之情形時，若超過30%，則玻璃變得不穩定而變得容易失透、光學玻璃之近紅外線截止性降低，故而欠佳。BaO之含量較佳為0～27%，更佳為0～25%。 ZnO雖並非必須成分，但有降低玻璃之熔融溫度、降低玻璃之液相溫度、及提高玻璃之化學耐久性等之效果。於含有ZnO之情形時，若超過10%，則玻璃容易變得不穩定、玻璃之熔解性變差，故而欠佳。ZnO之含量較佳為0～8%，更佳為0～5%。 CuO係用以截止近紅外線之必須成分。若光學玻璃中之CuO之含量未達0.5%，則於使光學玻璃之厚度變薄時未充分地獲得CuO之效果，若超過20%，則可視範圍透過率降低，故而欠佳。CuO之含量較佳為0.8～19%，更佳為1.0～18%。 再者，實施形態1之光學玻璃中之Cu之以陽離子%計的含量如上述般為0.5～25%，較佳之含量亦如上所示。又，於上述Cl、Br、I分別形成CuCl、CuBr、CuI之情形時，光學玻璃中之Cu之陽離子%係該鹵化銅中之Cu成分與其他Cu成分之合計含量。 實施形態1之光學玻璃亦可含有0～3%之Sb2
O3
作為任意成分。Sb2
O3
雖並非必須成分，但有提高光學玻璃之可視範圍透過率之效果。於含有Sb2
O3
之情形時，若超過3%，則玻璃之穩定性降低，故而欠佳。Sb2
O3
之含量較佳為0～2.5%，更佳為0～2%。 實施形態1之光學玻璃可於無損本發明之效果之範圍內，進而含有SiO2
、SO3
、B2
O3
等磷酸玻璃所通常含有之其他成分作為任意成分。該等成分之含量之合計較佳為3%以下。 又，實施形態1之光學玻璃係如上述般含有結晶，較佳為含有選自CuCl、CuBr及CuI中之至少1種之結晶者。 實施形態1之光學玻璃亦可進而含有Ag作為任意成分。實施形態1之光學玻璃中之Ag之含量及含有形態係如上所示。 ＜實施形態2之光學玻璃＞ 實施形態2之光學玻璃以陽離子%計含有 P5+
：20～50% Al3+
：5～20% R+
：15～40%(其中，R+
表示Li+
、Na+
及K+
之總量) R'2+
：5～30%(其中，R'2+
表示Mg2+
、Ca2+
、Sr2+
、Ba2+
、及Zn2+
之總量) Cu2+
與Cu+
之總量：0.5～25%，且 以陰離子%計含有 F-
：10～70%。 於本說明書中，所謂「陽離子%」及「陰離子%」，係以下所示之單位。首先，將光學玻璃之構成成分分成陽離子成分與陰離子成分。並且，所謂「陽離子%」，係於將光學玻璃中所含之全部陽離子成分之合計含量設為100莫耳%時，以百分率表示各陽離子成分之含量之單位。所謂「陰離子%」，係於將光學玻璃中所含之全部陰離子成分之合計含量設為100莫耳%時，以百分率表示各陰離子成分之含量之單位。 實施形態2之光學玻璃除F-
以外，亦含有O2-
作為陰離子成分，且含有選自Cl-
、Br-
及I-
中之至少1種。實施形態2之光學玻璃中之O2-
之含量係如下所示，選自Cl-
、Br-
及I-
中之至少1種之含量及含有形態係如上所示。 於以下說明如上述般限定構成本發明之實施形態2之光學玻璃的各成分之含量(陽離子%、陰離子%表示)之原因。於以下之說明中，關於實施形態2之光學玻璃之含有成分之含量「%」，只要沒有特別事先說明，則關於陽離子成分為陽離子%，關於陰離子成分為陰離子%。 (陽離子成分) P5+
係形成玻璃之主成分(玻璃形成氧化物)，且係用以提高光學玻璃之近紅外光範圍之截止性之必須成分，若未達20%，則未充分地獲得P5+
之效果，若超過50%，則玻璃變得不穩定，耐候性降低，故而欠佳。P5+
之含量較佳為20～48%，更佳為21～46%，進而較佳為22～44%。 Al3+
係形成玻璃之主成分(玻璃形成氧化物)，且係用以提高耐候性等之必須成分，若未達5%，則未充分地獲得Al3+
之效果，若超過20%，則玻璃變得不穩定，又光學玻璃之近紅外線截止性降低，故而欠佳。Al3+
之含量較佳為6～18%，更佳為6.5～15%，進而較佳為7～13%。 R+
(其中，R+
表示Li+
、Na+
及K+
之總量)係用以降低玻璃之熔融溫度、降低玻璃之液相溫度、及使玻璃穩定等之必須成分，若未達15%，則未充分地獲得R+
之效果，若超過40%，則玻璃變得不穩定，故而欠佳。R+
之含量較佳為15～38%，更佳為16～37%，進而較佳為17～36%。再者，R+
係指Li+
、Na+
、及K+
之總量、即Li+
＋Na+
＋K+
。又，R+
係選自Li+
、Na+
及K+
中之1種或2種以上，於2種以上之情形時，亦可為任意之組合。 Li+
係用以降低玻璃之熔融溫度、降低玻璃之液相溫度、及使玻璃穩定等之必須成分。若未達5%，則未充分地獲得Li+
之效果，若超過40%，則玻璃變得不穩定，故而欠佳。Li+
之含量較佳為8～38%，更佳為10～35%，進而較佳為15～30%。 Na+
雖並非必須成分，但係用以降低玻璃之熔融溫度、降低玻璃之液相溫度、及使玻璃穩定等之成分。於含有Na+
之情形時，若未達5%，則未充分地獲得Na+
之效果，若超過40%，則玻璃變得不穩定，故而欠佳。Na+
之含量較佳為5～35%，更佳為6～30%。 K+
雖並非必須成分，但係用以降低玻璃之熔融溫度、降低玻璃之液相溫度等之成分。於含有K+
之情形時，若未達0.1%，則未充分地獲得K+
之效果，若超過30%，則玻璃變得不穩定，故而欠佳。K+
之含量較佳為0.5～25%，更佳為0.5～20%。 R'2+
(其中，R'2+
表示Mg2+
、Ca2+
、Sr2+
、Ba2+
、及Zn2+
之總量)係用以降低玻璃之熔融溫度、降低玻璃之液相溫度、使玻璃穩定、及提高玻璃之強度等之必須成分。若未達5%，則未充分地獲得R'2+
之效果，若超過30%，則玻璃變得不穩定、光學玻璃之近紅外線截止性降低、及玻璃之強度降低等，故而欠佳。R'2+
之含量較佳為5～28%，更佳為7～25%，進而較佳為9～23%。再者，R'2+
係指Mg2+
、Ca2+
、Sr2+
、Ba2+
、及Zn2+
之總量、即Mg2+
＋Ca2+
＋Sr2+
＋Ba2+
＋Zn2+
。又，R'2+
係選自Mg2+
、Ca2+
、Sr2+
、Ba2+
及Zn2+
中之1種或2種以上，於2種以上之情形時，亦可為任意之組合。 Mg2+
係用以降低玻璃之熔融溫度、降低玻璃之液相溫度、及提高玻璃之強度等之成分。然而，Mg2+
有使玻璃變得不穩定而變得容易失透之傾向，於含有Mg2+
之情形時，若未達1%，則未充分地獲得Mg2+
之效果，若超過30%，則玻璃變得極不穩定、玻璃之熔解溫度上升等，故而欠佳。Mg2+
之含量較佳為1～25%，更佳為1～20%。 Ca2+
雖並非必須成分，但係用以降低玻璃之熔融溫度、降低玻璃之液相溫度、使玻璃穩定、及提高玻璃之強度等之成分。於含有Ca2+
之情形時，若未達1%，則未充分地獲得Ca2+
之效果，若超過30%，則玻璃變得不穩定而變得容易失透，故而欠佳。Ca2+
之含量較佳為1～25%，更佳為1～20%。 Sr2+
雖並非必須成分，但係用以降低玻璃之熔融溫度、降低玻璃之液相溫度、及使玻璃穩定等之成分。於含有Sr2+
之情形時，若未達1%，則未充分地獲得Sr2+
之效果，若超過30%，則玻璃變得不穩定而變得容易失透、玻璃之強度降低，故而欠佳。Sr2+
之含量較佳為1～25%，更佳為1～20%。 Ba2+
雖並非必須成分，但係用以降低玻璃之熔融溫度、降低玻璃之液相溫度、及使玻璃穩定等之成分。於含有Ba2+
之情形時，若未達0.1%，則未充分地獲得Ba2+
之效果，若超過30%，則玻璃變得不穩定而變得容易失透、玻璃之強度降低，故而欠佳。Ba2+
之含量較佳為1～25%，更佳為1～20%。 Zn2+
雖並非必須成分，但有降低玻璃之熔融溫度、降低玻璃之液相溫度、及提高玻璃之化學耐久性等之效果。於含有Zn2+
之情形時，若未達1%，則未充分地獲得Zn2+
之效果，若超過30%，則玻璃變得不穩定而變得容易失透、玻璃之熔解性變差，故而欠佳。Zn2+
之含量較佳為1～25%，更佳為1～20%。 實施形態2之光學玻璃中之作為陽離子成分之Cu的含量、即Cu2+
與Cu+
之合計含量係上述鹵化銅中之Cu成分與其他Cu成分的合計量。具體而言，Cu之含量如上述般為0.5～25%，較佳之含量亦如上所示。 Cu2+
係用以截止近紅外線之必須成分，含量較佳為0.1%以上且未達25%。若該含量未達0.1%，則於使光學玻璃之厚度變薄時未充分地獲得Cu2+
之效果，若為25%以上，則光學玻璃之可視範圍透過率降低，又因無法含有Cu+
，故而欠佳。Cu2+
之含量較佳為0.2～24%，更佳為0.3～23%，進而較佳為0.4～22%。 Cu+
係與Cl、Br、I進行反應而以鹵化銅結晶之形式析出，藉此可對光學玻璃賦予明顯截止紫外線之效果。Cu+
之含量較佳為0.1～15%。若該含量未達0.1%，則未充分地獲得Cu+
之效果，若超過15%，則減弱光學玻璃之藍色之強度，故而欠佳。Cu+
之含量較佳為0.2～13%，更佳為0.3～12%，進而較佳為0.4～11%。 實施形態2之光學玻璃亦可含有0～1%之Sb3+
作為任意之陽離子成分。Sb3+
雖並非必須成分，但有提高可視範圍透過率之效果。於含有Sb3+
之情形時，若超過1%，則玻璃之穩定性降低，故而欠佳。Sb3+
之含量較佳為0.01～0.8%，更佳為0.05～0.5%，進而較佳為0.1～0.3%。 實施形態2之光學玻璃可於無損本發明之效果之範圍內，進而含有Si、B等氟磷酸玻璃所通常含有之其他成分作為任意之陽離子成分。該等成分之含量之合計較佳為5%以下。 (陰離子成分) O2-
係用以使玻璃穩定、用以提高光學玻璃之可視範圍透過率、用以提高強度或硬度或彈性模數等機械特性、及用以降低紫外線透過率之必須成分，含量較佳為30～90%。若O2-
之含量未達30%，則未充分地獲得O2-
之效果，若超過90%，則玻璃變得不穩定、耐候性降低，故而欠佳。O2-
之含量更佳為30～80%，進而較佳為30～75%。 F-
係用以使玻璃穩定、用以提高耐候性之必須成分，若未達10%，則未充分地獲得F-
之效果，若超過70%，則有光學玻璃之可視範圍透過率降低、強度或硬度或彈性模數等機械特性降低、揮發性變高而脈理增加等之虞，故而欠佳。F-
之含量較佳為10～50%，更佳為15～40%。 本發明之實施形態2之光學玻璃由於必須含有F成分，故而耐候性優異。具體而言，能夠抑制由與氛圍中之水分之反應所引起之光學玻璃表面的變質或透過率之減少。關於耐候性之評價，係例如使用高溫高濕槽，將經光學研磨之光學玻璃樣品於65℃、相對溫度90%之高溫高濕槽中保持1000小時。並且，能夠目視觀察光學玻璃表面之泛黃狀態而進行評價。又，亦可將投入於高溫高濕槽之前之光學玻璃之透過率與在高溫高濕槽中保持了1000小時後之光學玻璃的透過率進行比較而進行評價。 實施形態2之光學玻璃可於無損本發明之效果之範圍內，進而含有S等氟磷酸玻璃所通常含有之其他成分作為任意之陰離子成分。該等成分之含量之合計較佳為5%以下。 又，實施形態2之光學玻璃係如上述般含有結晶，較佳為含有選自CuCl、CuBr及CuI中之至少1種之結晶者。再者，實施形態2之光學玻璃中之結晶成分之含量以濾波器玻璃之結晶度計較佳為與上述相同之範圍。 實施形態2之光學玻璃亦可進而含有Ag作為任意之陽離子成分。實施形態2之光學玻璃中之Ag之含量及含有形態係如上所示。 繼而，對本發明之實施形態1之光學玻璃及實施形態2之光學玻璃所共通的作為上述各成分以外之任意成分之其他成分的含量進行說明。再者，於本說明書中，所謂實質上不含有，意指並非意圖作為原料使用，關於自原料成分或製造步驟中混入之不可避免之雜質，視為不含有。 本發明之光學玻璃較佳為PbO、As2
O3
、V2
O5
、YbF3
、及GdF3
實質上均不含有。PbO係降低玻璃之黏度、提高製造作業性之成分。又，As2
O3
係作為於範圍廣泛之溫度範圍中可產生澄清氣體之優異之澄清劑發揮作用的成分。然而，PbO及As2
O3
由於為環境負荷物質，故而較理想為儘可能地不含有。V2
O5
由於在可視範圍內具有吸收，故而較理想為於要求可視範圍透過率較高之固態攝像元件用近紅外線截止濾波器玻璃中儘可能地不含有。YbF3
、GdF3
雖係使玻璃穩定之成分，但原料相對高價而會導致成本提高，因此較理想為儘可能地不含有。 本發明之光學玻璃可添加具有形成玻璃之陽離子之硝酸鹽化合物或硫酸鹽化合物作為氧化劑或澄清劑。氧化劑有如下效果：藉由增加光學玻璃中之Cu全部量中之Cu2+
離子之比例而使近紅外線之截止性提高。關於硝酸鹽化合物或硫酸鹽化合物之添加量，相對於原料混合物，以外加比例添加計較佳為0.5～10質量%。若添加量未達0.5質量%，則難以顯現出透過率改善之效果，若超過10質量%，則玻璃之形成容易變困難。更佳為1～8質量%，進而較佳為3～6質量%。 作為硝酸鹽化合物，有Al(NO3
)3
、LiNO3
、NaNO3
、KNO3
、Mg(NO3
)2
、Ca(NO3
)2
、Sr(NO3
)2
、Ba(NO3
)2
、Zn(NO3
)2
、Cu(NO3
)2
等。作為硫酸鹽化合物，有Al2
(SO4
)3
・16H2
O、Li2
SO4
、Na2
SO4
、K2
SO4
、MgSO4
、CaSO4
、SrSO4
、BaSO4
、ZnSO4
、CuSO4
等。 又，本發明之光學玻璃較佳為波長450～600 nm下之光之平均透過率為80%以上。 又，本發明之光學玻璃於設為厚度0.03～0.3 mm之情形時，較佳為成為透過率50%之波長為600～650 nm。藉由設為此種條件，可使要求薄型之感測器實現所需之光學特性。進而，於設為厚度0.03～0.3 mm之情形時，藉由波長450 nm下之透過率為80%以上，而成為具有可視範圍之光之透過率較高之光學特性的近紅外線截止濾波件。 透過率之值係以成為厚度0.03～0.3 mm之情形之值的方式進行換算。透過率之換算係使用以下之式1進行。再者，Ti1
係指測定樣品之內部透過率(除去正面及背面之反射損耗之資料)、t1
係指測定樣品之厚度(mm)，Ti2
係指換算值之透過率，t2
係指進行換算之厚度(本發明之情形時，0.03～0.3 mm)。 [數1]再者，本發明之光學玻璃即便處在為了應對攝像裝置或其搭載機器之小型化、薄型化而光學玻璃之厚度較薄的狀態，亦可獲得良好之分光特性。作為光學玻璃之厚度，較佳為1 mm以下，更佳為0.8 mm以下，進而較佳為0.6 mm以下，最佳為0.4 mm以下。又，光學玻璃之厚度之下限值並無特別限定，若考慮於光學玻璃製造時或組入至攝像裝置中時之搬送中難以破損之強度，則較佳為0.03 mm以上，更佳為0.05 mm以上，進而較佳為0.07 mm以上，最佳為0.1 mm以上。 本發明之光學玻璃之特徵在於：為光學玻璃單質且具備上述之光學特性，但為了進一步提高光學特性或保護光學玻璃免受水分等之影響，亦可於光學玻璃表面設置抗反射膜或紅外線截止膜、紫外線及紅外線截止膜等光學薄膜。該等光學薄膜係包含單層膜或多層膜者，可藉由蒸鍍法或濺鍍法等公知之方法而形成。又，與上述同樣地，為了提高光學特性或保護光學玻璃免受水分等之影響，亦可將含有吸收紅外線或紫外線之色素成分之樹脂膜設置於光學玻璃表面。 本發明之光學玻璃可以下述方式進行製作。 首先，以所獲得之光學玻璃成為上述組成範圍之方式秤量原料並進行混合(混合步驟)。將該原料混合物收容於鉑坩堝中，於電爐內於700～1300℃之溫度下進行加熱熔解(熔解步驟)。充分地進行攪拌、澄清後，澆鑄於模具內，進行使結晶析出之步驟(結晶析出步驟)，然後進行切斷、研磨而成形為特定厚度之平板狀(成形步驟)。 於上述製造方法之熔解步驟中，較佳為對於包含氟磷酸玻璃與結晶之光學玻璃、例如實施形態2之光學玻璃，將玻璃熔解中之玻璃之最高溫度設為950℃以下，且對於包含磷酸玻璃與結晶之光學玻璃、例如實施形態1之光學玻璃，將玻璃熔解中之玻璃之最高溫度設為1280℃以下。其原因在於：若玻璃熔解中之玻璃之最高溫度超過上述溫度，則透過率特性變差、及於氟磷酸玻璃中促進氟之揮散而使玻璃變得不穩定。上述溫度於氟磷酸玻璃中更佳為900℃以下，進而較佳為850℃以下。於磷酸玻璃中，更佳為1250℃以下，進而較佳為1200℃以下。 又，若上述熔解步驟中之溫度變得過低，則產生於熔解中發生失透、熔落耗費時間等問題，故而於氟磷酸玻璃時較佳為700℃以上，更佳為750℃以上。於磷酸玻璃時更佳為800℃以上，進而較佳為850℃以上。於本發明之光學玻璃之製造方法中，較佳為於以下之結晶析出步驟之前玻璃成分未結晶化，因此，熔解步驟中之溫度較佳為設為上述範圍。 繼上述熔解步驟之後進行之結晶析出步驟較佳為藉由緩冷、或緩冷及熱處理進行。於氟磷酸玻璃時，緩冷較佳為以0.1～2℃/分鐘之速度進行直至成為200～250℃。於磷酸玻璃時，較佳為以0.1～2℃/分鐘之速度進行直至成為200～250℃。 又，於藉由緩冷及熱處理進行結晶析出步驟之情形時，於氟磷酸玻璃時，較佳為進行與上述緩冷之條件同樣之緩冷後，進行自緩冷後之溫度升溫至400～600℃之熱處理。同樣地，於磷酸玻璃時，較佳為進行與上述緩冷之條件同樣之緩冷後，進行自緩冷後之溫度升溫至350～600℃之熱處理。 於本發明之光學玻璃之製造方法中，於此種結晶析出步驟中在玻璃中析出結晶。所獲得之本發明之光學玻璃係包含非晶質(玻璃)部分與結晶部分之光學玻璃。再者，於結晶析出步驟中，較佳為使選自CuCl、CuBr及CuI中之至少1種之結晶於玻璃中析出。藉由使CuCl、CuBr、CuI之結晶析出，而能夠減少所獲得之光學玻璃中除結晶部分外之非晶質(玻璃)部分之Cu+
量，且亦能夠賦予紫外線之明顯截止效果，故而較佳。 本發明之光學玻璃可適宜地用作為近紅外線截止濾波件。有關數位相機等所使用之固態攝像元件，其高感度化或高清化之腳步持續前行，藉由使用近紫外線之截止特性良好、且可視範圍之光之透過率(尤其是藍光之透過率)較高之本發明之光學玻璃作為固態攝像裝置的近紅外線截止濾波件，可獲得色再現性良好，耀斑、偽色、重影等雜訊成分之產生得到了抑制之攝像圖像。 [實施例] 以下表示本發明之實施例及比較例。 將本發明之實施例與比較例示於表1～表3。例1-1、例1-2係關於磷酸玻璃之本發明之光學玻璃之實施例，例1-3係關於磷酸玻璃之本發明之光學玻璃之比較例。例2-1、例2-4～例2-8係關於氟磷酸玻璃之本發明之光學玻璃之實施例，例2-2、例2-3係關於氟磷酸玻璃之本發明之光學玻璃之比較例。 [光學玻璃之製作] 以成為表1所示之組成(氧化物基準之質量%表示)及表2、表3所示之組成(陽離子%、陰離子%)的方式秤量原料並進行混合，放入至內容積約400 cc之鉑坩堝內，於800～1300℃之溫度下進行2小時熔融、澄清、攪拌，然後，澆鑄至已預熱至大約300～500℃之長50 mm×寬50 mm×高20 mm之長方形模具中。 關於本發明之實施例(例1-1、例1-2、例2-1、例2-4～例2-8)，澆鑄至長方形之模具中後，進行緩冷、或緩冷及熱處理(例1-1、例1-2：於460℃下保持1小時後，以1℃/分鐘冷卻至室溫，繼而於480℃下保持1小時後，以1℃/分鐘冷卻至室溫；例2-1：於360℃下保持1小時後，以1℃/分鐘冷卻至室溫；例2-4、例2-6～例2-8：於360℃下保持1小時後，以1℃/分鐘冷卻至室溫，繼而於410℃下保持2小時後，以1℃/分鐘冷卻至室溫；例2-5：於410℃下保持1小時後，以1℃/分鐘冷卻至室溫)。關於比較例(例1-3、例2-2、例2-3)，係進行緩冷(例1-3：於460℃下保持1小時後，以1℃/分鐘冷卻至室溫；例2-2、例2-3：於360℃下保持1小時後，以1℃/分鐘冷卻至室溫)。於各例中，獲得長50 mm×寬50 mm×厚20 mm之塊狀光學玻璃。將研削該光學玻璃後，進行研磨直至成為所需之厚度所得之玻璃板用於評價。 再者，關於各光學玻璃之原料，分別於P5+
之情形時使用H3
PO4
及/或Al(PO3
)3
；於Al3+
之情形時使用AlF3
、Al(PO3
)3
及/或Al2
O3
；於Li+
之情形時使用LiF、LiNO3
、Li2
CO3
及/或LiPO3
；於Mg2+
之情形時使用MgF2
及/或MgO及/或Mg(PO3
)2
；於Sr2+
之情形時使用SrF2
、SrCO3
及/或Sr(PO3
)2
；於Ba2+
之情形時使用BaF2
、BaCO3
及/或Ba(PO3
)2
；於Na+
之情形時使用NaCl及/或NaBr及/或NaI及/或NaF及/或Na(PO3
)；於K+
、Ca2+
、Zn2+
之情形時使用氟化物、碳酸鹽及/或偏磷酸鹽；於Sb3+
之情形時使用Sb2
O3
；於Cu2+
、Cu+
之情形時使用CuO、CuCl、CuBr。於Ag+
之情形時使用AgNO3
。 [評價] 針對各例中所獲得之玻璃板，結晶析出之有無可藉由透過型電子顯微鏡(TEM：Transmission Electron Microscope)等進行確認。進而，藉由紫外可見近紅外分光光度計(日本分光公司製造，V570)測定波長450～600 nm之光之透過率。關於例1-1～例1-3，獲得換算為厚度0.3 mm之透過率(於有玻璃板之表面反射之情況下算出)。關於例2-1～例2-8，獲得換算為厚度0.05 mm(於有玻璃板之表面反射之情況下算出)之透過率。於表1、2、3中表示結晶之有無、波長450～600 nm之光之平均透過率及450 nm之光之透過率。又，於表1中表示Cu(Cu2+
、Cu+
之合計)之以陽離子%計之含量、及Cl＋Br＋I之以陰離子%計之含量。 [表1]
[表2]
[表3]
針對以上述方式製作之各光學玻璃之光學特性，評價以下之項目。 (波長與透過率之近似直線之斜率) 斜率(S)之決定方法係如下所示。 對光學玻璃之分光透過率進行測定。繼而，特定300 nm～450 nm之波長頻帶之光之透過率成為50%的波長(整數值、λ50(300-450)
)。此處，於根據顯示分光透過率之曲線獲得之波長不會成為整數值的情形時，將最接近之整數值設為透過率成為50%之波長。然後，以λ50(300-450)
為中心，決定自λ50(300-450)
直至向短波長側及長波長側分別離開3 nm之波長的每1 nm之透過率資料7個。然後，根據該7個資料而製作以波長為X軸、以透過率為Y軸之近似直線，將所獲得之近似直線之斜率設為上述之波長與透過率之近似直線的斜率。 將利用該方法所決定之實施例、比較例之斜率(S)示於表4、表5、表6中。 (波長450 nm～480 nm之波長頻帶之光之平均透過率) 對光學玻璃之分光透過率進行測定。然後，根據所獲得之分光透過率，算出波長450 nm～480 nm之波長頻帶之光之平均透過率。 將利用該方法所獲得之實施例、比較例之平均透過率示於表4、表5、表6中。 (紫外線側之透過率50%之波長與紅外線側之透過率50%之波長的差) 將上述中所獲得之λ50(300-450)
設為紫外線側之透過率50%之波長。同樣地，特定600 nm～700 nm之波長頻帶之光之透過率成為50%的波長(整數值、λ50(600-700)
)。然後，根據兩資料之差量算出波長之差(λ50(600-700)
－λ50(300-450)
)。 將利用該方法所獲得之實施例、比較例之波長之差示於表4、表5、表6中。 (平均吸光係數之比率) 光學玻璃之平均吸光係數之比率之決定方法係如下所示。 對光學玻璃之分光透過率進行測定。然後，根據所獲得之分光透過率，分別算出波長450 nm～480 nm之波長頻帶之平均吸光係數(ε(450-480)
)及波長700 nm～850 nm之波長頻帶之平均吸光係數(ε(700-850)
)。然後，用波長700 nm～850 nm之波長頻帶之平均吸光係數除以波長450 nm～480 nm之波長頻帶之平均吸光係數，藉此決定平均吸光係數之比率(ε(700-850)
/ε(450-480)
)。 將利用該方法所獲得之實施例、比較例之平均吸光係數之比率示於表4、表5、表6中。 [表4]
[表5]
[表6]
根據表4、表5、表6，本發明之實施例之各光學玻璃相對於比較例之各光學玻璃，近紫外線之截止特性陡峭(斜率(S)陡峭)。藉此，能夠使不需要之近紫外線之透過率變得極低，因此能夠抑制攝像圖像中之耀斑、偽色、重影等之產生。 本發明之實施例之各光學玻璃相對於比較例之各光學玻璃，可視範圍之藍光之透過率尤高。藉此，能夠獲得色再現性良好之攝像圖像。 本發明之實施例之各光學玻璃之可視範圍之波段範圍(λ50(600-700)
－λ50(300-450)
)較廣。藉此，能夠獲得色再現性良好之攝像圖像。 本發明之實施例之各光學玻璃相對於比較例之各光學玻璃，平均吸光係數之比率(ε(700-850)
/ε(450-480)
)較高。即，本發明之實施例之各光學玻璃一面確實地截止應遮斷之近紅外線之光，一面欲透過之可視範圍之藍光之透過率較高。如上所述，由於具備多樣化之光學特性，故而能夠獲得色再現性良好之攝像圖像。 [產業上之可利用性] 根據本發明，可獲得藉由確實地截止近紫外線而抑制偽色或耀斑等之產生，且可視範圍之光(尤其是藍光)之透過率較高之光學玻璃，故而於用於高感度化、高清化之固體攝像裝置之近紅外線截止濾波器玻璃之情形時，尤其是藍光之透過率較高而色再現性良好。又，由於近紫外線之截止特性較高，故而能夠抑制攝像圖像中之耀斑、偽色、重影等雜訊之產生。Hereinafter, embodiments of the present invention will be described. The optical glass of the present invention must include a glass as a main body and a crystal contained in the glass. It should be noted that the optical characteristics of the optical glass in this specification are those having a surface reflection caused by a difference in refractive index between the optical glass and air. The optical glass of the present invention can be preferably used as a near-infrared cut filter glass in a solid-state imaging device. The near-infrared cut-off filter glass is disposed between the imaging optical system (lens group) and the solid-state imaging element (sensor) in the solid-state imaging device or on the subject side of the imaging optical system (the opposite of the solid-state imaging element side). The optical glass of the present invention has optical characteristics of transmitting light in the visible range and absorbing ultraviolet and infrared rays. In addition, the optical glass of the present invention is one that absorbs infrared and ultraviolet rays and has a wavelength and a transmittance calculated in a wavelength range of 3 nm before and after the light transmittance in the wavelength band of 300 nm to 450 nm becomes 50%. The optical characteristics of the slope of the approximate straight line are 3 or more. Hereinafter, "the slope of the approximate straight line of the wavelength and the transmittance calculated in the wavelength range of 3 nm before and after the light transmittance in the wavelength band of 300 nm to 450 nm becomes 50% and the wavelength is 3" is also referred to as "slope (S) ". By having such optical characteristics, it is possible to reliably cut off near-ultraviolet rays and suppress generation of false colors, flares, and the like. In addition, because the near-ultraviolet rays are cut off by the absorption effect of optical glass rather than by the reflection effect of optical multilayer films, the change in optical characteristics accompanying oblique incidence of light is extremely small, even due to stray light in solid-state imaging devices When oblique incident light of near-ultraviolet light is incident on optical glass, near-ultraviolet light can be reliably cut off. In the optical glass, if the slope (S) is less than 3, a part of near-ultraviolet rays is transmitted, so there is a concern that false colors, flares, and the like are generated. The optical glass system slope (S) of the present invention is 3 or more. The slope (S) is preferably 3.5 or more, and more preferably 4 or more. In addition, if the slope (S) exceeds 20, adjustment of the glass composition of the optical glass is extremely difficult and the manufacturing cost becomes high, which is not preferable. The slope (S) is preferably 20 or less, and more preferably 15 or less. In addition, the slope of the approximate straight line of the wavelength and the transmittance calculated in the above-mentioned so-called light transmittance in the wavelength band of 300 nm to 450 nm becomes 50% of the wavelength and the wavelength range of 3 nm (slope (Slope (S )), Specifically, determined by the following method. First, the spectral transmittance of optical glass is measured. Next, the wavelength (integer value) at which the light transmittance in the wavelength band of 300 nm to 450 nm becomes 50% is specified. Here, when the wavelength obtained from the curve showing the spectral transmittance does not become an integer value, the nearest integer value is regarded as the wavelength at which the transmittance becomes 50%. The wavelength at which the transmittance becomes 50% (hereinafter also referred to as "λ50 (300-450)
”), And determine 7 self-λ50 (300-450)
Transmission data at intervals of 1 nm to wavelengths of 3 nm from the short-wavelength side and long-wavelength side, respectively. For example, in the case where the transmittance becomes 50% and the wavelength is 380 nm, the data of the wavelength and transmittance at 377 nm, 378 nm, 379 nm, 380 nm, 381 nm, 382 nm, and 383 nm (calculated by 7 Each). Then, an approximate straight line with the wavelength [nm] as the X-axis and the transmittance [%] as the Y-axis is prepared based on the 7 data, and the slope [% / nm] of the obtained approximate straight line is set as the slope (S) . In the optical glass of the present invention, the average transmittance of light having a wavelength of 450 nm to 480 nm is preferably 80% or more. By having such characteristics, when the optical glass of the present invention is used in a solid-state imaging device, for example, the transmittance of blue light in the visible range is high, and a captured image having excellent color reproducibility can be obtained. Moreover, in order to obtain the color balance with other wavelength components in the visible range in accordance with the transmittance of blue light, the sensitivity of the sensor was adjusted. Therefore, by using the optical glass of the present invention, it is possible to realize high-sensitivity imaging that maximizes the original light-receiving sensitivity of the sensor. The average transmittance is more preferably 81% or more, and even more preferably 82% or more. In addition, if the above-mentioned average transmittance exceeds 92%, it is extremely difficult to adjust the glass composition of the optical glass and the manufacturing cost becomes high, which is unfavorable. The above average transmittance is preferably 92% or less, and more preferably 91% or less. The optical glass of the present invention is preferably a wavelength at which the transmittance of light in a wavelength band of 600 nm to 700 nm becomes 50% (hereinafter, also described as "λ50 (600-700)
”) Minus the wavelength at which the light transmittance in the wavelength band of 300 nm to 450 nm becomes 50% (λ50 (300-450)
) The value obtained, λ50 (600-700)
－Λ50 (300-450)
It is in the range of 200 nm to 300 nm. By having such characteristics, the transmittance of light in the visible range is high, and a captured image with excellent color reproducibility can be obtained with high sensitivity. Furthermore, the above-mentioned wavelength interval (λ50 (600-700)
－Λ50 (300-450)
) Is preferably 220 nm to 290 nm, and more preferably 230 nm to 280 nm. The optical glass of the present invention preferably has an average absorption coefficient (hereinafter referred to as "ε(700-850)
”) With respect to the average absorption coefficient (hereinafter referred to as“ ε(450 - 480)
"Case"), ε(700-850)
/ ε(450-480)
It is 33 or more. By having such characteristics, when the optical glass of the present invention is used in, for example, a solid-state imaging device, it is possible to reliably cut off the near-infrared rays that are not required for a captured image while changing the transmittance of blue light in the visible range High, it is possible to obtain a captured image with excellent color reproducibility with high sensitivity. Furthermore, the ratio of the average absorbance coefficient (ε(700-850)
/ ε(450-480)
) Is preferably 34 or more, and more preferably 35 or more. If the ratio of the average absorbance coefficient (ε(700-850)
/ ε(450-480)
) Exceeds 80, it is extremely difficult to adjust the glass composition of the optical glass and the manufacturing cost becomes high, so it is not good. Ratio of average transmittance (ε(700-850)
/ ε(450-480)
) Is preferably 80 or less, and more preferably 70 or less. For near-infrared cut-off filter glass, it is ideal to consider both increasing the transmittance of light with a wavelength of 450 nm to 480 nm and reducing the transmittance of light with a wavelength of 700 nm to 850 nm. Regarding the previous near-infrared cut filter glass, in order to improve the transmittance of light with a wavelength of 450 nm to 480 nm, there are methods to reduce the Cu concentration in the glass, but in this case, there is a light with a wavelength of 700 nm to 850 nm. The disadvantage of higher transmission. In addition, in order to reduce the transmittance of light with a wavelength of 700 nm to 850 nm, there is a method to increase the Cu concentration. However, in this case, there is a drawback that the transmittance of light with a wavelength of 450 nm to 480 nm becomes low. That is, regarding the near-infrared cut-off filter glass, it was originally difficult to balance the increase of the transmittance of light with a wavelength of 450 nm to 480 nm and the decrease of the transmittance of light with a wavelength of 700 nm to 850 nm, and it is necessary to adopt a compromise with any of the characteristics , Or any method that achieves a balance between the two. The details of the optical glass of the present invention are described below, but the Cu component in the optical glass is related to both the transmittance of light having a wavelength of 450 nm to 480 nm and the transmittance of light having a wavelength of 700 nm to 850 nm. It was found that by reducing the transmittance of Cu with a wavelength of 450 nm to 480 nm,+
Ions are precipitated as crystals in glass as halides to minimize the Cu in the amorphous (glass) part+
The amount of ions present allows the above-mentioned optical characteristics to be obtained. Furthermore, the Cu+
In the case where ions are precipitated as crystals in glass in the form of a halide, Cu in an amorphous portion that reduces the transmittance of light having a wavelength of 700 nm to 850 nm2+
The influence of ions is almost non-existent, so the transmittance of light with a wavelength of 450 nm to 480 nm can be increased while maintaining the better optical characteristics of light with a low transmittance at a wavelength of 700 nm to 850 nm. In addition, since the halides of Cu precipitated as crystals in the glass have steep absorption characteristics in the ultraviolet range, the optical glass of the present invention can also cut off near-ultraviolet rays which are not required for photographed images. The optical glass of the present invention must contain P and Cu as cationic components, and at least one selected from Cl, Br, and I as an anionic component, and the content of the above-mentioned Cu is 0.5 to 25% in terms of cation%. The glass contains crystals. That is, the optical glass of the present invention includes glass and crystals. Glass is an amorphous component and is a main component of the optical glass of the present invention. In addition, the crystal is preferably a crystal containing a component contained in the glass as crystals deposited in the glass. In this specification, the content of each component means the content in the optical glass. In addition, in the following description, when it is only called "glass", it means the glass which is an amorphous component in optical glass. P is the main component (glass-forming oxide) that forms glass, and is an essential component to improve the cut-off of the near-infrared range of optical glass. P in glass e.g. P5+
Contains. Cu is an essential component for cutting off near-infrared rays. Cu in glass such as Cu2+
, Cu+
Contains. If the content of Cu in the optical glass is less than 0.5%, the effect of Cu is not sufficiently obtained when the thickness of the optical glass is reduced. If it exceeds 25%, the transmittance in the visible range is reduced, which is not good. The content of Cu is preferably 0.5 to 19%, more preferably 0.6 to 18%, and still more preferably 0.7 to 17%. Moreover, the so-called Cu content refers to Cu in glass2+
, Cu+
And the total amount of the Cu component in the crystal. The optical glass of the present invention contains at least one selected from Cl, Br, and I as an anionic component. Cl, Br, and I may be combined to contain two or more kinds. Cl, Br and I-
Br-
, And I-
Contains. The content of Cl, Br, and I in the optical glass is preferably 0.01 to 20% based on the total amount of anion%. If the content of Cl, Br, and I is less than 0.01%, it is difficult to precipitate crystals. If it exceeds 20%, the volatility may increase and the veins in the glass may increase. The content of Cl, Br, and I in the optical glass is more preferably 0.01 to 15%, and further preferably 0.02 to 10%. Cl-
Br-
, I-
Cu in glass+
Carry out the reaction, Cl-
CuCl, Br-
CuBr, I-
The system forms CuI. With these components, the obtained optical glass can obviously cut off light in the near ultraviolet range. Cl-
Br-
, I-
It can be appropriately selected in accordance with the wavelength of light which is to be cut off in the near ultraviolet range. The crystal contained in the optical glass of the present invention is preferably a crystal containing at least one selected from the group consisting of CuCl, CuBr, and CuI. That is, CuCl, CuBr, and CuI contained in the optical glass are preferably precipitated as crystals. When at least one selected from the group consisting of CuCl, CuBr, and CuI is precipitated in a crystalline state, it is possible to improve the apparent cutoff of light in the ultraviolet range. The optical glass of the present invention preferably contains Ag as a cationic component. Ag is bonded to at least one selected from the group consisting of Cl, Br, and I to precipitate silver halide (for example, AgCl). In this case, the AgCl system functions as a crystal nucleus and has a function of easily precipitating CuCl crystals. The content of Ag in the optical glass is preferably 0.01 to 5% in terms of cation%. If it is less than 0.01%, the effect of precipitating crystals is not sufficiently obtained. If it exceeds 5%, Ag colloids are formed and the transmittance of visible light decreases, which is not preferable. In addition, components other than silver halide that become crystalline nuclei can be analyzed or introduced in optical glass, and at least one type of crystal selected from CuCl, CuBr, and CuI can be precipitated. The crystalline component in the optical glass of the present invention mainly includes at least one selected from the group consisting of CuCl, CuBr, and CuI, and may also include a crystalline nucleus formed by combining Ag with at least one selected from the group consisting of Cl, Br, and I, or other Crystal nucleus. Next, with regard to the optical glass of the present invention, the optical glass of the two embodiments, that is, the optical glass of Embodiment 1 including phosphoric acid glass and crystals, and the optical glass of Embodiment 2 including fluorophosphate glass and crystals will be described as examples. The optical glass according to the first embodiment of the present invention contains, as an oxide-based mass% expression: P2
O5
: 35 ～ 75% Al2
O3
： 5 ～ 15% R2
O: 3 to 30% (wherein R2
O means Li2
O, Na2
O and K2
Total amount of O) R'O: 3 to 35% (where R'O represents the total amount of MgO, CaO, SrO, BaO, and ZnO) CuO: 0.5 to 20%. The optical glass of Embodiment 1 contains at least one selected from the group consisting of Cl, Br, and I. The content and morphology of at least one selected from Cl, Br, and I in the optical glass of Embodiment 1 are as described above. The reason for limiting the content of each component constituting the optical glass according to the first embodiment of the present invention as described above will be described below. In the following description, as for the content "%" of the component contained in the optical glass of Embodiment 1, unless otherwise specified, it is the mass% of an oxide basis. P2
O5
It is the main component (glass-forming oxide) that forms glass and is an essential component to improve the cutoff of the near-infrared range of optical glass. If it is less than 35%, P is not sufficiently obtained.2
O5
If the effect exceeds 75%, the glass becomes unstable and the weather resistance decreases, and the remaining amount of at least one selected from the group consisting of Cl, Br, and I in the optical glass decreases, and crystals are not sufficiently precipitated. good. P2
O5
The content is preferably 38 to 73%, and more preferably 40 to 72%. Al2
O3
It is the main component (glass-forming oxide) that forms glass and is an essential component for improving weather resistance. If it is less than 5%, Al is not sufficiently obtained.2
O3
If the effect is more than 15%, the glass becomes unstable, and the near-infrared cutoff property of the optical glass is reduced, which is not good. Al2
O3
The content is preferably 5.5 to 12%, and more preferably 6 to 10%. R2
O (where, R2
O means Li2
O, Na2
O and K2
The total amount of O) is a component used to reduce the melting temperature of the glass, lower the liquidus temperature of the glass, and stabilize the glass. If it is less than 3%, R is not sufficiently obtained.2
When the effect of O exceeds 30%, the glass becomes unstable, which is unfavorable. R2
The content of O is preferably 5 to 28%, and more preferably 6 to 25%. Furthermore, R2
O is Li2
O, Na2
O and K2
The total amount of O, that is, Li2
O ＋ Na2
O ＋ K2
O. Again, R2
O is selected from Li2
O, Na2
O and K2
One or two or more of O may be used in any combination. Li2
O is a component used to lower the melting temperature of glass, lower the liquidus temperature of glass, and stabilize glass. Yu Li2
In the case of O, if it exceeds 15%, the glass becomes unstable, which is not preferable. Li2
The content of O is preferably 0 to 10%, and more preferably 0 to 8%. Na2
O is a component used to lower the melting temperature of glass, lower the liquidus temperature of glass, and stabilize glass. In Na2
In the case of O, if it exceeds 25%, the glass becomes unstable, which is not preferable. Na2
The content of O is preferably 0 to 22%, and more preferably 0 to 20%. K2
O is not an essential component, but it is a component used to lower the melting temperature of glass and the liquidus temperature of glass. In K2
In the case of O, if it exceeds 25%, the glass becomes unstable, and the thermal expansion rate becomes remarkably large, which is not preferable. K2
The content of O is preferably 0 to 20%, and more preferably 0 to 15%. R'O (where R'O represents the total amount of MgO, CaO, SrO, BaO, and ZnO) is used to reduce the melting temperature of the glass, reduce the liquidus temperature of the glass, stabilize the glass, and increase the strength of the glass, etc. Essential ingredients. If it is less than 3%, the effect of R'O is not sufficiently obtained. If it exceeds 35%, the glass becomes unstable, the near-infrared cutoff of the optical glass is reduced, and the strength of the glass is reduced, which is not good. The content of R'O is preferably 3.5 to 32%, and more preferably 4 to 30%. In addition, R'O means the total amount of MgO, CaO, SrO, BaO, and ZnO, that is, R'O is MgO + CaO + SrO + BaO + ZnO. R'O is one or two or more selected from MgO, CaO, SrO, BaO, and ZnO. When two or more are used, any combination may be used. MgO is a component used to lower the melting temperature of glass, lower the liquidus temperature of glass, and increase the strength of glass. However, MgO tends to destabilize the glass and easily devitrify it. In particular, when it is necessary to set a high Cu content, it is preferable not to contain MgO. When MgO is contained, if it exceeds 5%, the glass becomes extremely unstable, and the near-infrared cutoff property of the optical glass is reduced, which is not preferable. The content of MgO is preferably 0 to 3%, and more preferably 0 to 2%. CaO is a component used to lower the melting temperature of glass, lower the liquidus temperature of glass, stabilize glass, and increase the strength of glass. When CaO is contained, when it exceeds 10%, the glass becomes unstable and becomes easily devitrified, and the near-infrared cutoff property of the optical glass is reduced, which is not preferable. The content of CaO is preferably 0 to 7%, and more preferably 0 to 5%. SrO is a component used to lower the melting temperature of glass, lower the liquidus temperature of glass, and stabilize glass. When SrO is contained, if it exceeds 15%, the glass becomes unstable and becomes easily devitrified, and the near-infrared cutoff property of the optical glass is reduced, which is not preferable. The content of SrO is preferably 0 to 12%, and more preferably 0 to 10%. Although BaO is not an essential component, it is a component for lowering the melting temperature of glass, lowering the liquidus temperature of glass, and stabilizing glass. When BaO is contained, if it exceeds 30%, the glass becomes unstable and easily devitrifies, and the near-infrared cutoff property of the optical glass is reduced, which is not preferable. The content of BaO is preferably 0 to 27%, and more preferably 0 to 25%. Although ZnO is not an essential component, it has the effects of lowering the melting temperature of glass, lowering the liquidus temperature of glass, and improving the chemical durability of glass. When ZnO is contained, if it exceeds 10%, the glass tends to be unstable and the melting property of the glass is deteriorated, which is not preferable. The content of ZnO is preferably 0 to 8%, and more preferably 0 to 5%. CuO is an essential component for cutting off near-infrared rays. If the content of CuO in the optical glass is less than 0.5%, the effect of CuO is not sufficiently obtained when the thickness of the optical glass is reduced, and if it exceeds 20%, the transmittance in the visible range is reduced, which is not good. The content of CuO is preferably 0.8 to 19%, and more preferably 1.0 to 18%. In addition, the content of Cu in the cation% in the optical glass of Embodiment 1 is 0.5 to 25% as described above, and the preferred content is also shown above. When Cl, Br, and I form CuCl, CuBr, and CuI, the cation% of Cu in the optical glass is the total content of the Cu component and other Cu components in the copper halide. The optical glass of Embodiment 1 may also contain 0 to 3% of Sb.2
O3
As an optional ingredient. Sb2
O3
Although it is not an essential component, it has the effect of increasing the transmittance of the visible range of the optical glass. Sb2
O3
In this case, if it exceeds 3%, the stability of the glass is reduced, which is not good. Sb2
O3
The content is preferably 0 to 2.5%, and more preferably 0 to 2%. The optical glass of the first embodiment may further contain SiO within a range that does not impair the effect of the present invention.2
, SO3
, B2
O3
Other components usually contained in isophosphoric acid glass are optional components. The total content of these ingredients is preferably 3% or less. The optical glass of Embodiment 1 contains crystals as described above, and preferably contains at least one crystal selected from the group consisting of CuCl, CuBr, and CuI. The optical glass of the first embodiment may further contain Ag as an optional component. The content and morphology of Ag in the optical glass of Embodiment 1 are as described above. <Optical glass of Embodiment 2> The optical glass of Embodiment 2 contains P as a cation%5+
： 20 ～ 50% Al3+
： 5 ～ 20% R+
: 15 ～ 40% (including R+
Means Li+
, Na+
And K+
Total) R '2+
: 5 to 30% (where R '2+
Represents Mg2+
, Ca2+
, Sr2+
Ba2+
, And Zn2+
Total) Cu2+
With Cu+
Total amount: 0.5 ～ 25%, and contains F as anion%-
: 10 to 70%. In this specification, the "cation%" and "anion%" are the units shown below. First, the constituent components of the optical glass are divided into a cationic component and an anionic component. The "cationic%" refers to a unit in which the content of each cationic component is expressed as a percentage when the total content of all cationic components contained in the optical glass is 100 mol%. The "anionic%" is a unit that expresses the content of each anionic component as a percentage when the total content of all anionic components contained in the optical glass is 100 mol%. Removal of F from optical glass of Embodiment 2-
In addition to O2-
As an anionic component and contains a member selected from Cl-
Br-
And I-
At least one of them. O in Optical Glass of Embodiment 22-
The content is shown below, selected from Cl-
Br-
And I-
The content and morphology of at least one of them are as described above. The reason for limiting the content (indicated by cation% and anion%) of each component constituting the optical glass according to the second embodiment of the present invention as described above will be described below. In the following description, as for the content "%" of the component contained in the optical glass of Embodiment 2, unless otherwise specified, the cationic component is cationic%, and the anionic component is anionic%. (Cationic component) P5+
It is the main component (glass-forming oxide) that forms glass and is an essential component to improve the cutoff of the near-infrared range of optical glass. If it is less than 20%, P is not sufficiently obtained.5+
If the effect is more than 50%, the glass becomes unstable and the weather resistance decreases, which is not good. P5+
The content is preferably 20 to 48%, more preferably 21 to 46%, and still more preferably 22 to 44%. Al3+
It is the main component (glass-forming oxide) that forms glass and is an essential component for improving weather resistance. If it is less than 5%, Al is not sufficiently obtained.3+
If the effect is more than 20%, the glass becomes unstable, and the near-infrared cutoff property of the optical glass is reduced, which is not good. Al3+
The content is preferably 6 to 18%, more preferably 6.5 to 15%, and even more preferably 7 to 13%. R+
(Where R+
Means Li+
, Na+
And K+
The total amount) is an essential component for lowering the melting temperature of glass, lowering the liquidus temperature of glass, and stabilizing glass.+
If the effect exceeds 40%, the glass becomes unstable, which is not satisfactory. R+
The content is preferably 15 to 38%, more preferably 16 to 37%, and still more preferably 17 to 36%. Furthermore, R+
Means Li+
, Na+
, And K+
The total amount, that is, Li+
＋ Na+
+ K+
. Again, R+
Selected from Li+
, Na+
And K+
One or two or more of them may be used in any combination. Li+
It is an essential component used to reduce the melting temperature of glass, lower the liquidus temperature of glass, and stabilize glass. If less than 5%, Li is not sufficiently obtained+
If the effect exceeds 40%, the glass becomes unstable, which is not satisfactory. Li+
The content is preferably 8 to 38%, more preferably 10 to 35%, and still more preferably 15 to 30%. Na+
Although it is not an essential component, it is a component used to lower the melting temperature of glass, lower the liquidus temperature of glass, and stabilize glass. In Na+
In this case, if less than 5%, Na is not sufficiently obtained+
If the effect exceeds 40%, the glass becomes unstable, which is not satisfactory. Na+
The content is preferably 5 to 35%, and more preferably 6 to 30%. K+
Although it is not an essential component, it is a component used to lower the melting temperature of glass and the liquidus temperature of glass. In K+
In this case, if it is less than 0.1%, K is not sufficiently obtained.+
If the effect is more than 30%, the glass becomes unstable, which is unfavorable. K+
The content is preferably 0.5 to 25%, and more preferably 0.5 to 20%. R '2+
(Where R '2+
Represents Mg2+
, Ca2+
, Sr2+
Ba2+
, And Zn2+
The total amount) is an essential component used to reduce the melting temperature of the glass, lower the liquidus temperature of the glass, stabilize the glass, and increase the strength of the glass. If less than 5%, R 'is not fully obtained2+
If the effect is more than 30%, the glass becomes unstable, the near-infrared cutoff of the optical glass is reduced, and the strength of the glass is reduced. R '2+
The content is preferably 5 to 28%, more preferably 7 to 25%, and still more preferably 9 to 23%. Furthermore, R '2+
Means Mg2+
, Ca2+
, Sr2+
Ba2+
, And Zn2+
The total amount, that is, Mg2+
+ Ca2+
＋ Sr2+
＋ Ba2+
＋ Zn2+
. Again, R '2+
Selected from Mg2+
, Ca2+
, Sr2+
Ba2+
And Zn2+
One or two or more of them may be used in any combination. Mg2+
It is used to reduce the melting temperature of glass, lower the liquidus temperature of glass, and increase the strength of glass. However, Mg2+
It tends to make the glass unstable and easily devitrified, and it contains Mg2+
In this case, if less than 1%, Mg is not sufficiently obtained2+
If the effect is more than 30%, the glass becomes extremely unstable, and the melting temperature of the glass increases, which is not satisfactory. Mg2+
The content is preferably 1 to 25%, and more preferably 1 to 20%. Ca2+
Although it is not an essential component, it is a component for reducing the melting temperature of glass, lowering the liquidus temperature of glass, stabilizing glass, and improving the strength of glass. Ca2+
In this case, if it is less than 1%, Ca is not sufficiently obtained.2+
When the effect exceeds 30%, the glass becomes unstable and easily devitrifies, which is not preferable. Ca2+
The content is preferably 1 to 25%, and more preferably 1 to 20%. Sr2+
Although it is not an essential component, it is a component for lowering the melting temperature of glass, lowering the liquidus temperature of glass, and stabilizing glass. Sr2+
In this case, if it is less than 1%, Sr is not sufficiently obtained.2+
If the effect is more than 30%, the glass becomes unstable and easily devitrifies, and the strength of the glass decreases, which is unfavorable. Sr2+
The content is preferably 1 to 25%, and more preferably 1 to 20%. Ba2+
Although it is not an essential component, it is a component for lowering the melting temperature of glass, lowering the liquidus temperature of glass, and stabilizing glass. In Ba2+
In this case, if it is less than 0.1%, Ba is not sufficiently obtained.2+
If the effect is more than 30%, the glass becomes unstable and easily devitrifies, and the strength of the glass decreases, which is unfavorable. Ba2+
The content is preferably 1 to 25%, and more preferably 1 to 20%. Zn2+
Although it is not an essential component, it has the effects of lowering the melting temperature of glass, lowering the liquidus temperature of glass, and improving the chemical durability of glass. Zn2+
In this case, if it is less than 1%, Zn is not sufficiently obtained.2+
When the effect exceeds 30%, the glass becomes unstable and easily devitrifies, and the melting property of the glass is deteriorated, which is not preferable. Zn2+
The content is preferably 1 to 25%, and more preferably 1 to 20%. Content of Cu as a cationic component in the optical glass of Embodiment 2, that is, Cu2+
With Cu+
The total content is the total amount of the Cu component and other Cu components in the copper halide. Specifically, the Cu content is 0.5 to 25% as described above, and the preferred content is also as described above. Cu2+
It is an essential component for cutting off near-infrared rays, and its content is preferably 0.1% or more and less than 25%. If the content is less than 0.1%, Cu is not sufficiently obtained when the thickness of the optical glass is reduced.2+
If the effect is 25% or more, the transmittance of the visible range of the optical glass decreases, and Cu cannot be contained.+
, So it is not good. Cu2+
The content is preferably 0.2 to 24%, more preferably 0.3 to 23%, and still more preferably 0.4 to 22%. Cu+
It reacts with Cl, Br, and I to precipitate in the form of copper halide crystals, thereby giving the optical glass the effect of significantly cutting off ultraviolet rays. Cu+
The content is preferably 0.1 to 15%. If the content is less than 0.1%, Cu is not sufficiently obtained+
If the effect is more than 15%, the blue strength of the optical glass is weakened, which is not good. Cu+
The content is preferably 0.2 to 13%, more preferably 0.3 to 12%, and still more preferably 0.4 to 11%. The optical glass of Embodiment 2 may also contain 0 to 1% of Sb.3+
As an arbitrary cationic component. Sb3+
Although it is not essential, it has the effect of increasing the transmittance in the visible range. Sb3+
In this case, if it exceeds 1%, the stability of the glass is reduced, which is not good. Sb3+
The content is preferably 0.01 to 0.8%, more preferably 0.05 to 0.5%, and still more preferably 0.1 to 0.3%. The optical glass according to the second embodiment may contain other components normally contained in fluorophosphate glass such as Si and B as arbitrary cationic components within a range that does not impair the effect of the present invention. The total content of these ingredients is preferably 5% or less. (Anionic component) O2-
It is used to stabilize the glass, to improve the visible range transmittance of optical glass, to improve mechanical properties such as strength or hardness or elastic modulus, and to reduce the UV transmittance. The content is preferably 30 to 90. %. If O2-
If the content is less than 30%, O is not sufficiently obtained2-
If the effect is more than 90%, the glass becomes unstable and the weather resistance decreases, which is not preferable. O2-
The content is more preferably 30 to 80%, and still more preferably 30 to 75%. F-
It is an essential component for stabilizing glass and improving weather resistance. If it is less than 10%, F is not sufficiently obtained.-
If the effect exceeds 70%, the transmittance in the visible range of the optical glass may decrease, the mechanical properties such as strength, hardness, or elastic modulus may decrease, the volatility may increase, and the veins may increase, which is not satisfactory. F-
The content is preferably 10 to 50%, and more preferably 15 to 40%. Since the optical glass according to the second embodiment of the present invention must contain an F component, it is excellent in weather resistance. Specifically, it is possible to suppress deterioration of the surface of the optical glass or decrease in transmittance caused by a reaction with moisture in the atmosphere. The evaluation of the weather resistance is, for example, using a high-temperature and high-humidity tank, and holding the optically polished optical glass sample in a high-temperature and high-humidity tank at 65 ° C and a relative temperature of 90% for 1,000 hours. In addition, the state of yellowing on the surface of the optical glass can be visually observed and evaluated. In addition, the transmittance of the optical glass before being put into the high-temperature and high-humidity tank may be compared with the transmittance of the optical glass after being held in the high-temperature and high-humidity tank for 1000 hours. The optical glass according to the second embodiment may contain other components normally contained in fluorophosphate glass such as S as an arbitrary anionic component, as long as the effect of the present invention is not impaired. The total content of these ingredients is preferably 5% or less. The optical glass of Embodiment 2 contains crystals as described above, and preferably contains at least one crystal selected from the group consisting of CuCl, CuBr, and CuI. The content of the crystalline component in the optical glass according to the second embodiment is preferably in the same range as that described above in terms of the crystallinity of the filter glass. The optical glass of Embodiment 2 may further contain Ag as an arbitrary cation component. The content and morphology of Ag in the optical glass of Embodiment 2 are as described above. Next, the content of other components which are common to the optical glass according to the first embodiment of the present invention and the optical glass according to the second embodiment as an arbitrary component other than the above-mentioned components will be described. In addition, in this specification, the term "substantially free" means that it is not intended to be used as a raw material, and unavoidable impurities mixed from raw material components or manufacturing steps are considered not to contain. The optical glass of the present invention is preferably PbO, As2
O3
, V2
O5
, YbF3
GdF3
They are not substantially contained. PbO is a component that lowers the viscosity of glass and improves manufacturing workability. Also, As2
O3
It is a component that functions as an excellent fining agent that generates fining gas in a wide temperature range. However, PbO and As2
O3
Since it is an environmentally hazardous substance, it is desirable not to contain it as much as possible. V2
O5
Since it has absorption in the visible range, it is desirable that the near-infrared cut-off filter glass for a solid-state imaging element that requires a high transmittance in the visible range is not contained as much as possible. YbF3
GdF3
Although it is a component for stabilizing glass, it is desirable that the raw material is not contained as much as possible because the raw material is relatively expensive and costs increase. In the optical glass of the present invention, a nitrate compound or a sulfate compound having glass-forming cations can be added as an oxidant or clarifier. The oxidant has the following effects: by increasing the amount of Cu in the total amount of Cu in the optical glass2+
The ratio of ions improves the cutoff of near-infrared rays. The addition amount of the nitrate compound or the sulfate compound is preferably 0.5 to 10% by mass based on the addition ratio to the raw material mixture. If the addition amount is less than 0.5% by mass, it is difficult to exhibit the effect of improving the transmittance, and if it exceeds 10% by mass, the formation of glass tends to be difficult. It is more preferably 1 to 8% by mass, and even more preferably 3 to 6% by mass. As nitrate compounds, there are Al (NO3
)3
LiNO3
NaNO3
KNO3
, Mg (NO3
)2
, Ca (NO3
)2
, Sr (NO3
)2
, Ba (NO3
)2
, Zn (NO3
)2
, Cu (NO3
)2
Wait. As a sulfate compound, there is Al2
(SO4
)3
・ 16H2
O, Li2
SO4
, Na2
SO4
K2
SO4
, MgSO4
CaSO4
, SrSO4
BaSO4
ZnSO4
CuSO4
Wait. In the optical glass of the present invention, the average transmittance of light at a wavelength of 450 to 600 nm is preferably 80% or more. In addition, when the optical glass of the present invention has a thickness of 0.03 to 0.3 mm, it is preferable that the wavelength having a transmittance of 50% is 600 to 650 nm. By setting such a condition, it is possible to realize a desired optical characteristic of a thin sensor. Furthermore, when the thickness is 0.03 to 0.3 mm, the near-infrared cut filter with optical characteristics of high transmittance of light in the visible range is obtained by having a transmittance at a wavelength of 450 nm of 80% or more. The value of the transmittance is converted into a value when the thickness is 0.03 to 0.3 mm. Conversion of the transmittance was performed using the following Equation 1. Furthermore, Ti1
Refers to the measurement of the internal transmittance of the sample (excluding the data on the front and back reflection loss), t1
Refers to the thickness (mm) of the test sample, Ti2
Refers to the transmittance of the converted value, t2
Refers to the thickness converted (in the case of the present invention, 0.03 to 0.3 mm). [Number 1]Furthermore, even if the optical glass of the present invention is in a state where the thickness of the optical glass is thin in order to cope with the miniaturization and thinning of the imaging device or the equipment on which it is mounted, it is possible to obtain good spectral characteristics. The thickness of the optical glass is preferably 1 mm or less, more preferably 0.8 mm or less, still more preferably 0.6 mm or less, and most preferably 0.4 mm or less. The lower limit of the thickness of the optical glass is not particularly limited. When considering the strength that is difficult to break during the manufacture of the optical glass or when it is incorporated into the imaging device, it is preferably 0.03 mm or more, and more preferably 0.05. mm or more, more preferably 0.07 mm or more, and most preferably 0.1 mm or more. The optical glass of the present invention is characterized in that it is a single element of optical glass and has the above-mentioned optical characteristics, but in order to further improve the optical characteristics or protect the optical glass from moisture and the like, an anti-reflection film or infrared cut-off can also be provided on the surface of the optical glass. Films, optical films such as ultraviolet and infrared cut films. These optical thin films include a single-layer film or a multilayer film, and can be formed by a known method such as a vapor deposition method or a sputtering method. In addition, in the same manner as described above, in order to improve the optical characteristics or protect the optical glass from moisture and the like, a resin film containing a pigment component that absorbs infrared or ultraviolet rays may be provided on the surface of the optical glass. The optical glass of the present invention can be produced in the following manner. First, the raw materials are weighed and mixed so that the obtained optical glass becomes the composition range described above (mixing step). The raw material mixture was stored in a platinum crucible, and was heated and melted in an electric furnace at a temperature of 700 to 1300 ° C (melting step). After sufficiently stirring and clarifying, it is cast into a mold, and a step of precipitating crystals (crystal precipitation step) is performed, followed by cutting and grinding to form a flat plate having a predetermined thickness (forming step). In the melting step of the above manufacturing method, it is preferred that for optical glass containing fluorophosphate glass and crystals, such as the optical glass of Embodiment 2, the highest temperature of the glass in the glass melting is set to 950 ° C or lower, and For glass and crystal optical glass, such as the optical glass of Embodiment 1, the highest temperature of the glass during melting of the glass is set to 1280 ° C or lower. The reason is that if the highest temperature of the glass during the melting of the glass exceeds the above-mentioned temperature, the transmittance characteristics are deteriorated, and the volatilization of fluorine in the fluorophosphate glass is promoted to make the glass unstable. The temperature in the fluorophosphate glass is more preferably 900 ° C or lower, and even more preferably 850 ° C or lower. In phosphoric acid glass, the temperature is preferably 1250 ° C or lower, and further preferably 1200 ° C or lower. In addition, if the temperature in the above melting step becomes too low, problems such as devitrification occurring during melting and time consuming for melting will occur. Therefore, it is preferably 700 ° C or higher, more preferably 750 ° C or higher, in the case of fluorophosphate glass. In the case of phosphoric acid glass, it is more preferably 800 ° C or more, and even more preferably 850 ° C or more. In the manufacturing method of the optical glass of this invention, it is preferable that the glass component is not crystallized before the following crystallization process, Therefore, it is preferable to set the temperature in a melting process to the said range. The crystal precipitation step performed after the melting step is preferably performed by slow cooling, or slow cooling and heat treatment. In the case of fluorophosphate glass, the slow cooling is preferably performed at a rate of 0.1 to 2 ° C / minute until it reaches 200 to 250 ° C. In the case of phosphoric acid glass, it is preferably performed at a rate of 0.1 to 2 ° C / minute until it becomes 200 to 250 ° C. In the case where the crystal precipitation step is performed by slow cooling and heat treatment, in the case of fluorophosphate glass, it is preferable to perform the slow cooling under the same conditions as the slow cooling, and then increase the temperature after the slow cooling to 400 to Heat treatment at 600 ° C. Similarly, in the case of phosphoric acid glass, it is preferable to perform a slow cooling similar to the above-mentioned slow cooling conditions, and then perform a heat treatment in which the temperature after the slow cooling is raised to 350 to 600 ° C. In the method for producing an optical glass of the present invention, crystals are precipitated in the glass in such a crystal precipitation step. The obtained optical glass of the present invention is an optical glass including an amorphous (glass) portion and a crystalline portion. In the crystal precipitation step, it is preferred that at least one crystal selected from the group consisting of CuCl, CuBr, and CuI be precipitated in glass. By precipitating the crystals of CuCl, CuBr, and CuI, it is possible to reduce the amount of Cu in the amorphous (glass) portion of the obtained optical glass other than the crystalline portion.+
It is also preferable because it can give a clear cut-off effect of ultraviolet rays. The optical glass of the present invention can be suitably used as a near-infrared cut filter. Regarding the solid-state imaging elements used in digital cameras, the steps of high sensitivity and high definition continue to advance. By using near-ultraviolet light, the cutoff characteristics are good and the transmittance of light in the visible range (especially the transmittance of blue light) The higher optical glass of the present invention is used as a near-infrared cut-off filter of a solid-state imaging device, and can obtain a captured image with good color reproducibility, and the generation of noise components such as flare, false color, and ghosting is suppressed. [Examples] Examples and comparative examples of the present invention are shown below. Examples and comparative examples of the present invention are shown in Tables 1 to 3. Examples 1-1 and 1-2 are examples of the optical glass of the present invention related to phosphate glass, and examples 1-3 are comparative examples of the optical glass of the present invention related to phosphate glass. Examples 2-1, 2-4 to 2-8 are examples of the optical glass of the present invention with respect to fluorophosphate glass, and Examples 2-2, 2-3 are examples of the optical glass of the present invention with respect to fluorophosphate glass Comparative example. [Production of optical glass] The raw materials were weighed and mixed so as to have the composition shown in Table 1 (indicated by the mass% of the oxide standard) and the composition shown in Tables 2 and 3 (the cation% and the anion%), and put In a platinum crucible with an internal volume of about 400 cc, melt, clarify, and stir at a temperature of 800 to 1300 ° C for 2 hours, and then cast to a length of 50 mm × 50 mm × preheated to about 300-500 ° C 20 mm high rectangular mold. Regarding the examples of the present invention (Example 1-1, Example 1-2, Example 2-1, Example 2-4 to Example 2-8), after being cast into a rectangular mold, slow cooling, or slow cooling and heat treatment were performed. (Example 1-1, Example 1-2: After holding at 460 ° C for 1 hour, cool to room temperature at 1 ° C / minute, and then hold at 480 ° C for 1 hour, then cool to room temperature at 1 ° C / minute; Example 2-1: After holding at 360 ° C for 1 hour, cool to room temperature at 1 ° C / min; Examples 2-4, 2-6 to 2-8: After holding at 360 ° C for 1 hour, ℃ / minute to cool to room temperature, and then kept at 410 ℃ for 2 hours, then cooled to room temperature at 1 ℃ / minute; Example 2-5: After holding at 410 ℃ for 1 hour, cooled to room temperature at 1 ℃ / minute temperature). For comparative examples (Example 1-3, Example 2-2, Example 2-3), slow cooling was performed (Example 1-3: After holding at 460 ° C for 1 hour, it was cooled to room temperature at 1 ° C / minute; Example 2-2, Example 2-3: After holding at 360 ° C for 1 hour, it was cooled to room temperature at 1 ° C / minute). In each case, a block-shaped optical glass having a length of 50 mm × a width of 50 mm × a thickness of 20 mm was obtained. After grinding this optical glass, the glass plate obtained by grinding until it became a desired thickness was used for evaluation. In addition, the raw materials for each optical glass are5+
H3
PO4
And / or Al (PO3
)3
; In Al3+
AlF3
, Al (PO3
)3
And / or Al2
O3
; Li+
LiF, LiNO3
Li2
CO3
And / or LiPO3
; In Mg2+
MgF2
And / or MgO and / or Mg (PO3
)2
; In Sr2+
SrF2
, SrCO3
And / or Sr (PO3
)2
; In Ba2+
BaF2
BaCO3
And / or Ba (PO3
)2
; In Na+
In the case of NaCl and / or NaBr and / or NaI and / or NaF and / or Na (PO3
); In K+
, Ca2+
Zn2+
In the case of fluoride, carbonate and / or metaphosphate; in Sb3+
Sb2
O3
; In Cu2+
, Cu+
In this case, CuO, CuCl, and CuBr are used. In Ag+
AgNO3
. [Evaluation] For the glass plate obtained in each example, the presence or absence of crystal precipitation can be confirmed with a transmission electron microscope (TEM: Transmission Electron Microscope) or the like. Furthermore, the transmittance of light having a wavelength of 450 to 600 nm was measured by an ultraviolet-visible-near-infrared spectrophotometer (manufactured by JASCO Corporation, V570). Regarding Examples 1-1 to 1-3, a transmittance (calculated when there is reflection on the surface of a glass plate) converted to a thickness of 0.3 mm was obtained. Regarding Examples 2-1 to 2-8, transmittances converted to a thickness of 0.05 mm (calculated when the surface of a glass plate was reflected) were obtained. Tables 1, 2, and 3 show the presence or absence of crystals, the average transmittance of light at a wavelength of 450 to 600 nm, and the transmittance of light at 450 nm. In addition, Table 1 shows Cu (Cu2+
, Cu+
Content) in terms of cation% and Cl + Br + I in terms of anion%. [Table 1]
[Table 2]
[table 3]
With respect to the optical characteristics of each optical glass produced as described above, the following items were evaluated. (Slope of approximate straight line of wavelength and transmittance) The method of determining the slope (S) is as follows. The spectral transmittance of the optical glass was measured. Then, the wavelength at which the transmittance of light in a specific wavelength band of 300 nm to 450 nm becomes 50% (integer value, λ50 (300-450)
). Here, when the wavelength obtained from the curve showing the spectral transmittance does not become an integer value, the closest integer value is set to a wavelength at which the transmittance becomes 50%. Then, take λ50 (300-450)
Centered, determined from λ50 (300-450)
Up to 7 pieces of transmittance data per 1 nm up to a wavelength of 3 nm to the short wavelength side and the long wavelength side, respectively. Then, an approximate straight line having a wavelength of the X-axis and a transmittance of the Y-axis is prepared based on the 7 pieces of data, and the slope of the obtained approximate straight line is set as the slope of the approximate straight line of the wavelength and transmittance described above. The slopes (S) of the examples and comparative examples determined by this method are shown in Table 4, Table 5, and Table 6. (Average transmittance of light in a wavelength band of 450 nm to 480 nm) The spectral transmittance of optical glass is measured. Then, based on the obtained spectral transmittance, the average transmittance of light in a wavelength band of 450 nm to 480 nm was calculated. The average transmittances of the examples and comparative examples obtained by this method are shown in Table 4, Table 5, and Table 6. (Difference between the wavelength of 50% transmittance on the ultraviolet side and the wavelength of 50% transmittance on the infrared side) The λ obtained in the above50 (300-450)
The wavelength was set at a wavelength of 50% on the ultraviolet side. Similarly, the wavelength at which the transmittance of light in a specific wavelength band of 600 nm to 700 nm becomes 50% (integer value, λ50 (600-700)
). Then, the difference between the wavelengths (λ50 (600-700)
－Λ50 (300-450)
). The differences in wavelengths of the examples and comparative examples obtained by this method are shown in Table 4, Table 5, and Table 6. (Ratio of average light absorption coefficient) The method of determining the ratio of the average light absorption coefficient of optical glass is as follows. The spectral transmittance of the optical glass was measured. Then, based on the obtained spectral transmittances, the average absorbance coefficients (ε of the wavelength bands of 450 nm to 480 nm are calculated, respectively.(450-480)
) And the average absorption coefficient (ε in the wavelength band of 700 nm to 850 nm)(700-850)
). Then, divide the average absorbance coefficient of the wavelength band of 700 nm to 850 nm by the average absorbance coefficient of the wavelength band of 450 nm to 480 nm to determine the ratio of the average absorbance coefficient (ε(700-850)
/ ε(450-480)
). The ratios of the average absorbance coefficients of the examples and comparative examples obtained by this method are shown in Table 4, Table 5, and Table 6. [Table 4]
[table 5]
[TABLE 6]
According to Table 4, Table 5, and Table 6, each optical glass according to the embodiment of the present invention has a steep cutoff characteristic (slope (S)) of near-ultraviolet rays compared to each optical glass of the comparative example. Thereby, the transmittance of the unnecessary near-ultraviolet rays can be extremely low, and thus the occurrence of flare, false colors, ghosts, and the like in a captured image can be suppressed. The optical glass of the examples of the present invention has a higher transmittance of blue light in the visible range than the optical glasses of the comparative examples. Thereby, a captured image with good color reproducibility can be obtained. The range of the visible range of each optical glass of the embodiment of the present invention (λ50 (600-700)
－Λ50 (300-450)
) Wider. Thereby, a captured image with good color reproducibility can be obtained. The ratio of the average light absorption coefficient (ε of each optical glass of the embodiment of the present invention to that of the comparative example)(700-850)
/ ε(450-480)
) Higher. That is, each optical glass according to the embodiment of the present invention has a high transmittance of blue light in the visible range to be transmitted while it cuts off the near-infrared light that should be cut off. As described above, since it has various optical characteristics, a captured image with good color reproducibility can be obtained. [Industrial Applicability] According to the present invention, it is possible to obtain optical glass having a high transmittance of light (especially blue light) in the visible range by suppressing generation of false colors or flares by reliably cutting off near-ultraviolet rays, Therefore, in the case of a near-infrared cut-off filter glass used in a high-sensitivity, high-definition solid-state imaging device, especially blue light has a high transmittance and good color reproducibility. In addition, the near-ultraviolet light has a high cut-off characteristic, so it is possible to suppress the occurrence of noise such as flare, false color, and ghost in the captured image.