JPS6363502B2 - - Google Patents
Info
- Publication number
- JPS6363502B2 JPS6363502B2 JP6196281A JP6196281A JPS6363502B2 JP S6363502 B2 JPS6363502 B2 JP S6363502B2 JP 6196281 A JP6196281 A JP 6196281A JP 6196281 A JP6196281 A JP 6196281A JP S6363502 B2 JPS6363502 B2 JP S6363502B2
- Authority
- JP
- Japan
- Prior art keywords
- glass
- lens
- ion exchange
- glass rod
- refractive index
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000011521 glass Substances 0.000 claims description 43
- 238000009826 distribution Methods 0.000 claims description 30
- 238000005342 ion exchange Methods 0.000 claims description 17
- 238000000034 method Methods 0.000 claims description 12
- 238000012545 processing Methods 0.000 claims description 7
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 6
- 238000010438 heat treatment Methods 0.000 claims description 5
- 229910008649 Tl2O3 Inorganic materials 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 3
- QTQRFJQXXUPYDI-UHFFFAOYSA-N oxo(oxothallanyloxy)thallane Chemical compound O=[Tl]O[Tl]=O QTQRFJQXXUPYDI-UHFFFAOYSA-N 0.000 claims description 3
- 230000007704 transition Effects 0.000 claims description 3
- 230000004075 alteration Effects 0.000 description 41
- 239000000203 mixture Substances 0.000 description 9
- FGIUAXJPYTZDNR-UHFFFAOYSA-N potassium nitrate Chemical compound [K+].[O-][N+]([O-])=O FGIUAXJPYTZDNR-UHFFFAOYSA-N 0.000 description 5
- 229910052716 thallium Inorganic materials 0.000 description 5
- 238000000137 annealing Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 230000003287 optical effect Effects 0.000 description 3
- 230000002093 peripheral effect Effects 0.000 description 3
- 238000005498 polishing Methods 0.000 description 3
- 229910001414 potassium ion Inorganic materials 0.000 description 3
- 239000011734 sodium Substances 0.000 description 3
- 239000006121 base glass Substances 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 150000002500 ions Chemical class 0.000 description 2
- 235000010333 potassium nitrate Nutrition 0.000 description 2
- 239000004323 potassium nitrate Substances 0.000 description 2
- 229910001415 sodium ion Inorganic materials 0.000 description 2
- BKVIYDNLLOSFOA-UHFFFAOYSA-N thallium Chemical compound [Tl] BKVIYDNLLOSFOA-UHFFFAOYSA-N 0.000 description 2
- -1 thallium ions Chemical class 0.000 description 2
- 238000013459 approach Methods 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 238000003856 thermoforming Methods 0.000 description 1
- 238000009827 uniform distribution Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C3/00—Glass compositions
- C03C3/04—Glass compositions containing silica
- C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
- C03C3/089—Glass compositions containing silica with 40% to 90% silica, by weight containing boron
Landscapes
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Glass Melting And Manufacturing (AREA)
- Re-Forming, After-Treatment, Cutting And Transporting Of Glass Products (AREA)
- Surface Treatment Of Glass (AREA)
- Glass Compositions (AREA)
Description
【発明の詳細な説明】
本発明は中心軸から周辺に向つて屈折率が連続
的に変化しているガラスあるいはプラスチツクか
らなる円柱状透明体の一端または両端面を凸状の
曲面に仕上げた屈折率分布型レンズに関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a refractor in which one end or both end surfaces of a cylindrical transparent body made of glass or plastic whose refractive index changes continuously from the central axis toward the periphery are finished with a convex curved surface. Regarding rate distribution lenses.
中心軸から半径方向へｒの距離の点における屈
折率ｎ（ｒ）が近似的に次式の２乗分布式
ｎ（ｒ）＝n0〔１−g2／２r2〕 ……(1)
で表わされる円柱状透明体は既に集束性光伝送体
としてよく知られている。但しn0は軸上屈折率、
ｇは２乗分布定数である。このような円柱状の光
伝送体の長さz0を０＜z0＜π／2gに選ぶとき、そ
の結像特性は両端面が平担でありながら通常の凸
レンズと同じであり、平行入射光線によつて出射
端より
s0＝cot（gz0）／n0g ……(2)
の位置に焦点が作られ屈折率分布型レンズとよば
れる。ところが実際の屈折率分布型レンズの屈折
率は(1)式の２乗分布からずれており、ｒの４次、
６次、………の偶数ベキで展開される高次収差係
数をもつている。今、屈折率分布を(1)式の代りに
収差を考慮して
n2（ｒ）＝n2 0〔１−（gr）2＋h4（gr）4
＋h6（gr）6〕 ……(3)
で表現することにする。ここでh4及びh6をそれぞ
れ４次及び６次の収差係数とする。このような収
差をもつレンズ体によつて作られる焦点は、(2)式
に代つてほぼ
ｓ＝cot（Ωz0）／nputΩ ……(4)
に位置する。ただし
Ω＝ｇ〔１−３／４（h4−２／３）（grio）2−（1
5／16h6＋15／64h4 2＋７／８h4−３／８）（grio）4〕
……(5)
で表わされて、nputは出射位置の屈折率、rioは入
射端面における中心軸から入射位置までの距離で
ある。(5)式によつて明らかなように距離rioが比較
的小さい近軸光線の場合はΩはｇにほぼ等しい
が、中心軸から比較的離れた位置に入射した平行
光線に対してはΩ≠ｇであり、上記焦点位置に△
ｓ＝ｓ−s0の差を生ずる。ここで出射端面を基準
として周辺光線によつて作られる焦点位置が近軸
光線によつて作られる焦点位置より遠い場合、即
ち△ｓ＞０の場合を正の軸上収差と定義し逆の△
ｓ＜０の場合を負の軸上収差と定義することにす
る。△ｓが正であるか負となるかはレンズの母材
ガラスの組成によつてきまる。例えばモル百分率
でNa2O（25−Ｘ）、Tl2OX、B2O315、SiO260の
組成のガラス（これをタイプと称する）と
Na2O（20−Ｘ）、Tl2OX、B2O320、SiO260の組
成のガラス（これをタイプと呼ぶ）からなる二
種の母材ロツドを540℃の硝酸カリ融液中に浸漬
して時間の経過と共にレンズ化の進行する過程を
軸上収差の測定により観察すると、第１図及び第
２図のＸ＝10の例に見られるように全く異る経過
を辿る。そしてレンズ化がほぼ終了した時点にお
いて第３図ａ，ｂに示すようにタイプのガラス
のレンズは△ｓ＞０、タイプのガラスのレンズ
は△ｓ＜０となることが実験で確められた。△ｓ
＞０の特性をもつたタイプと△ｓ＜０の特性を
もつたタイプの屈折率分布型レンズの屈折率分
布を干渉顕微鏡による干渉縞の解析から求めた例
をそれぞれ第４図と第５図に示す。図中の破線は
屈折率の理想分布ｎ（ｒ）＝no・sech（gr）を示す
もので、第４図から明らかなようにタイプの分
布は比較的中心に近い所は理想分布にほぼ近いか
僅かに勾配が大きく比較的中心から離れた所から
周辺にかけては理想分布からはずれて勾配がゆる
やかになつている。 The refractive index n(r) at a point at a distance r in the radial direction from the central axis is approximated by the square distribution formula of the following equation: n(r)=n 0 [1-g 2 /2r 2 ] ...(1) The cylindrical transparent body represented by is already well known as a focusing light transmission body. However, n 0 is the axial refractive index,
g is a square distribution constant. When the length z 0 of such a cylindrical optical transmission body is selected to be 0 < z 0 < π/2g, its imaging characteristics are the same as a normal convex lens even though both end surfaces are flat, and parallel incidence A focal point is created by the light beam at the position s 0 = cot (gz 0 )/n 0 g (2) from the output end, and it is called a gradient index lens. However, the refractive index of an actual gradient index lens deviates from the square distribution of equation (1), and has the fourth order of r,
It has higher-order aberration coefficients that are expanded in even powers of the 6th order. Now, considering the aberration instead of formula (1) for the refractive index distribution, n 2 (r) = n 2 0 [1-(gr) 2 + h 4 (gr) 4 + h 6 (gr) 6 ] ...( 3) Let us express it as follows. Here, h 4 and h 6 are the fourth-order and sixth-order aberration coefficients, respectively. The focal point created by a lens body having such an aberration is approximately located at s=cot(Ωz 0 )/n put Ω (4) instead of equation (2). However, Ω=g [1-3/4 (h 4 -2/3) (g io ) 2 - (1
5/16h 6 +15/64h 4 2 +7/8h 4 -3/8) (gr io ) 4 ]
...(5) where n put is the refractive index at the exit position, and r io is the distance from the central axis to the incidence position on the entrance end surface. As is clear from equation (5), in the case of a paraxial ray with a relatively small distance r io , Ω is approximately equal to g, but for a parallel ray incident at a position relatively far from the central axis, Ω ≠g, and △ at the above focal position
This results in a difference of s = s - s 0 . Here, when the focal position created by the peripheral rays is farther from the focal position created by the paraxial rays with the exit end surface as a reference, that is, when Δs>0, it is defined as positive axial aberration, and the opposite Δ
The case where s<0 is defined as negative axial aberration. Whether Δs is positive or negative depends on the composition of the base glass of the lens. For example, a glass with a mole percentage of Na 2 O (25-X), Tl 2 OX, B 2 O 3 15, and SiO 2 60 (this is called a type)
Two types of base material rods consisting of glasses with compositions of Na 2 O (20-X), Tl 2 OX, B 2 O 3 20, and SiO 2 60 (these are called types) were placed in a potassium nitrate melt at 540°C. When observing the progress of lens formation over time by measuring axial aberrations after immersing the lens in water, a completely different process is observed, as seen in the example of X=10 in FIGS. 1 and 2. It was confirmed through experiments that when lens formation was almost completed, △s>0 for the type of glass lens and △s<0 for the type of glass lens, as shown in Figure 3 a and b. . △s
Figures 4 and 5 show examples of the refractive index distributions of a type with a characteristic of >0 and a type of gradient index lens with a characteristic of △s<0, respectively, obtained from analysis of interference fringes using an interference microscope. Shown below. The dashed line in the figure shows the ideal distribution of refractive index n(r)=no・sech(gr), and as is clear from Figure 4, the type distribution near the center is almost close to the ideal distribution. The slope is slightly large, and from the area relatively far away from the center to the periphery, the slope deviates from the ideal distribution and becomes gentler.
逆にタイプの分布は第５図の通り比較的中心
付近の勾配は理想分布よりややゆるく比較的中心
から離れた領域から周辺にかけては屈折率の勾配
は理想分布に比較して大きくなつている。このよ
うな特性はレンズガラスの組成がそれぞれある特
定範囲内、言い換えれば前述の４次、６次の収差
係数h4、h6がそれぞれある特定範囲内にある場合
に生ずる特性であつて、この特性により長さz0が
０＜z0＜π／2gのレンズの比較的中心付近に入射
した平行光線によつて作られる焦点位置に対して
比較的中心から離れた位置に入射した平行光線に
よつて作られる焦点が出射端面を基準にしてより
遠い所に結ばれたり（△ｓ＞０、タイプの場
合）より近くに結ばれたり（△ｓ＜０、タイプ
の場合）してその中間に最小錯乱円が出来る。 On the contrary, in the type distribution, as shown in FIG. 5, the gradient near the center is a little gentler than the ideal distribution, and the gradient of the refractive index from the region relatively far from the center to the periphery is larger than the ideal distribution. These characteristics occur when the composition of the lens glass is within a certain range, or in other words, when the fourth-order and sixth-order aberration coefficients h 4 and h 6 are each within a certain range. Due to its characteristics, the focal point created by a parallel ray of light incident relatively near the center of a lens with length z 0 of 0 < z 0 < π/2g corresponds to a parallel ray of light incident at a position relatively far from the center. The focal point thus created may be located farther away from the output end face (in the case of △s>0, type) or closer (in the case of △s<0, in the case of type), or somewhere in between. A circle of least confusion is created.
一方、最近になつてビデオデイスクの開発が急
速に進み、その光学的読み取り・書き込み用素子
として開口角が大きく収差の小さい微小な高性能
レンズが要求されている。 On the other hand, the development of video disks has progressed rapidly in recent years, and small high-performance lenses with large aperture angles and small aberrations are required as optical reading/writing elements.
これに対し前述したタイプのガラスを用いた
屈折率分布型レンズは端面を所定曲率の凸曲面と
することにより軸上収差をほぼゼロに補正するこ
とが可能ではあるが屈折率上昇に大きな効果のあ
るタリウム（Tl）の濃度をあまり高くすること
ができず、大きな開口角を得るためにタリウム濃
度を上げると屈折率分布が周辺において急峻とな
りこの部分の軸上収差が大きくなつて収差補正の
ための凸曲面加工が困難になるという問題があ
る。また、タイプのガラスでは負の軸上収差を
もつため補正は端面を凹曲面に加工する必要があ
り、ビデオデイスクの光学的読み取り素子のよう
に直径数ミリの小さなものでは凹曲面研摩は極め
て困難であるとともに得られたとしても取扱い中
あるいは使用中にレンズに縁欠けを生じ易く実用
的でない。 On the other hand, with the gradient index lens using the type of glass mentioned above, it is possible to correct the axial aberration to almost zero by making the end face a convex curved surface with a predetermined curvature, but it is not very effective in increasing the refractive index. It is not possible to make the concentration of a certain thallium (Tl) very high, and when the thallium concentration is increased in order to obtain a large aperture angle, the refractive index distribution becomes steep at the periphery and the axial aberration in this area becomes large. There is a problem in that it becomes difficult to process convex curved surfaces. In addition, since this type of glass has negative axial aberration, it is necessary to process the end face into a concave curved surface to correct it, and polishing a concave curved surface is extremely difficult for small objects with a diameter of several millimeters, such as the optical reading element of a video disk. Moreover, even if obtained, the edges of the lens tend to chip during handling or use, making it impractical.
本発明は、上述の問題を解決する新規な屈折率
分布型レンズの製造方法を提供するものであり、
第１の発明は大きな開口角をとり得るすなわち、
イオン交換によつて中心と周辺とで大きな屈折率
差を得られるが端面平面のレンズとしたときに若
干は負の軸上収差を生じるような特定のガラス組
成を選定し、このガラスからなるロツドをイオン
交換して屈折率分布を与えた後、このガラスとの
の間で実質的にイオン交換を生じないような加熱
媒体中で熱処理し、これにより周辺部の屈折率分
布を修正して収差を補正することを要旨とする。
また第２の発明に従つた方法では、上述の第１発
明方法の処理によつて負の軸上収差を若干の正の
軸上収差に転換させ、しかる後、ガラスロツドの
端面を所定曲率の凸曲面に加工することによつて
収差を設計値内に精密に制御する。 The present invention provides a novel method for manufacturing a gradient index lens that solves the above-mentioned problems,
The first invention can have a large aperture angle, that is,
We selected a specific glass composition that can obtain a large refractive index difference between the center and the periphery through ion exchange, but produces a slight negative axial aberration when used as a lens with flat end faces. After ion-exchanging the glass to give it a refractive index distribution, it is heat-treated in a heating medium that does not substantially cause ion exchange with the glass, thereby correcting the refractive index distribution in the peripheral area and eliminating aberrations. The purpose is to correct the
Further, in the method according to the second invention, the negative axial aberration is converted into a slight positive axial aberration by the process of the first invention method described above, and then the end face of the glass rod is made convex with a predetermined curvature. By processing the surface into a curved surface, aberrations can be precisely controlled within the design value.
以下本発明についてさらに詳しく説明する。 The present invention will be explained in more detail below.
本発明において使用するレンズ母材ガラスは主
成分がモル百分率でSiO257〜63％、B2O317〜23
％、Na2O5〜17％、Tl2O3〜15％の範囲内になけ
ればならない。この範囲外では充分な開口角がと
れなかつたりあるいはロツドへの熱成形が困難に
なるなどの問題を生じ本発明方法に適当でない。 The main components of the lens base glass used in the present invention are SiO 2 57-63% and B 2 O 3 17-23% in molar percentage.
%, Na2O5 ~17%, Tl2O3 ~15%. Outside this range, problems such as not being able to obtain a sufficient opening angle or difficulty in thermoforming into a rod occur, making it unsuitable for the method of the present invention.
なお、上記主成分以外に例えば重量百分率で
ZnO4％以下、As2O3またはSb2O30.5％以下など
の副成分を含んでいても差し障えない。 In addition, in addition to the above main components, for example, in weight percentage
There is no problem even if it contains subcomponents such as ZnO 4% or less, As 2 O 3 or Sb 2 O 3 0.5% or less.
上記組成のガラスでロツドを成形した後、この
ガラスロツドを硝酸カリウム塩浴などのイオン交
換媒体中で処理してガラス中のタリウムイオンお
よびナトリウムイオンと媒体中のカリウムイオン
とのイオン交換を行なつてガラスロツド内に中心
から周辺に向けて連続的に減小する屈折率分布を
与える。 After forming a rod with glass having the above composition, the glass rod is treated in an ion exchange medium such as a potassium nitrate salt bath to perform ion exchange between thallium ions and sodium ions in the glass and potassium ions in the medium. Provides a refractive index distribution that decreases continuously from the center to the periphery.
得られる屈折率分布は周辺に近づくにつれて理
想分布ｎ（ｒ）＝n0・sech（gr）から外れて勾配が
急になるカーブを示し、両端面を平行平面に研摩
仕上げして得られるレンズは前述した負の軸上収
差を示す。 The resulting refractive index distribution deviates from the ideal distribution n(r)= n0・sech(gr) as it approaches the periphery, showing a curve with a steeper slope.The lens obtained by polishing both end surfaces into parallel planes is This shows the negative axial aberration mentioned above.
そこで本発明では所定のイオン交換処理を行な
つた後にガラスロツドを、このガラスとの間で実
質的にイオン交換を生じない媒体例えば空気中あ
るいは油浴中で上記ガラスの転移温度域すなわ
ち、500℃ないし550℃（ガラスの粘性をηとして
logη＝10〜13）で20時間以上保持することによ
り、ガラス内のタリウムイオンを周辺に向けて移
動させるとともに周辺部のカリウムイオンを内部
に向けて移動させ、これにより周辺部の屈折率を
上昇させて理想分布に近づける方向に屈折率分布
を修正する。 Therefore, in the present invention, after performing a predetermined ion exchange treatment, the glass rod is placed in a medium that does not substantially cause ion exchange with the glass, such as air or an oil bath, at a temperature within the transition temperature range of the glass, that is, 500°C. to 550℃ (with glass viscosity as η)
logη = 10 to 13) for more than 20 hours, the thallium ions in the glass move toward the periphery, and the potassium ions in the periphery move inward, thereby increasing the refractive index of the periphery. The refractive index distribution is corrected in a direction that brings it closer to the ideal distribution.
以上のようにして分布修正を終えたロツドを所
定長さに切断し両端面を平行平面に研摩仕上げす
ることによつて開口数（NA）の大なしかも収差
の非常に小さい高性能の屈折率分布型レンズを得
ることができる。 By cutting the rod whose distribution has been corrected as described above into a predetermined length and polishing both end faces into parallel planes, a high-performance refractive index with a large numerical aperture (NA) and very small aberrations can be obtained. A distributed lens can be obtained.
ただし、イオン拡散に厳密に制御することは一
般に難しく上記のようなイオン交換後の熱処理の
みでは収差補正に自ら限界があり、またガラス組
成の選択のみでは得られるレンズの開口角にも限
界がある。そこでさらに収差の小さいしかも開口
角の大なレンズを安定して得るためには屈折率分
布修正の熱処理を行なつて軸上収差を若干のプラ
ス側に補正し、次いでガラスロツドを切断・研摩
してレンズ化するに当り、一方の端面又は両方の
端面を所定曲率の凸曲面、一般的には凸球面に加
工して収差を厳密に補正する。この凸球面加工に
より同一組成ガラスのフラツト端面の屈折率分布
型レンズに比べて開口角を大きく向上させること
ができ、１つの工程付加で上記の両要求を同時に
満足させることができる。そして前述した本発明
方法に従えば曲率半径がロツド半径の10〜１倍の
範囲内の研摩の容易な比較的ゆるやかな曲面に加
工するだけで済む。 However, it is generally difficult to strictly control ion diffusion, and there is a limit to aberration correction with only heat treatment after ion exchange as described above, and there is also a limit to the aperture angle of the lens that can be obtained by selecting only the glass composition. . Therefore, in order to stably obtain a lens with even smaller aberrations and a larger aperture angle, heat treatment is performed to modify the refractive index distribution to slightly correct the axial aberration to the positive side, and then the glass rod is cut and polished. When forming a lens, one or both end surfaces are processed into a convex curved surface with a predetermined curvature, generally a convex spherical surface, to precisely correct aberrations. By processing this convex spherical surface, the aperture angle can be greatly improved compared to a gradient index lens with a flat end face made of glass of the same composition, and both of the above requirements can be satisfied at the same time by adding one process. According to the above-described method of the present invention, it is only necessary to form a relatively gently curved surface whose radius of curvature is within the range of 10 to 1 times the radius of the rod and which is easy to polish.
なお、本発明に係るレンズをビデオデイスクの
読取りや書込みに利用する場合にはデイスクが正
の軸上収差をもつことを考慮して最終的には僅か
に負の軸上収差をもつようにしておき、これが正
の軸上収差をもつデイスクとの組合せによつて補
償されるようにしておくことが望ましい。 In addition, when using the lens according to the present invention for reading or writing on a video disk, it is necessary to take into account that the disk has positive axial aberration, so that it has a slight negative axial aberration. It is desirable that this be compensated by a combination with a disk having positive axial aberration.
また端面の形は球面状のみならず非球面状であ
つてもよいことはいうまでもない。 It goes without saying that the shape of the end face is not limited to a spherical shape, but may also be an aspherical shape.
実施例 １
モル百分率でNa2O10％、Tl2O10％、B2O320
％、SiO260％のガラスを溶融し、直径３mmのガ
ラスロツドを作成した。これを530℃に保たれた
硝酸カリウム融液中に608時間浸しガラス中の
Tl+イオンとNa+イオンとを融液のK+イオンに交
換し、処理後所定長さに切断し両端面を平行平面
に研摩してパラメータがno＝1.605、ｇ＝0.274mm
-1、h4＝1.50、h6＝−99.2で表わされるレンズ体
を得た。上記特性値を用い一端面上の種々の位置
で入射した平行光線の他端面出射後に結ぶ焦点位
置を光線追跡法で求め軸上収差を求めた結果、第
６図のように負の軸上収差をもつことが確認され
た。そこでこのレンズ体を空気中で540℃、450時
間、焼鈍した結果、比較的周辺部に近い領域の屈
折率勾配がゆるくなり、屈折率分布のパラメータ
がｇ＝0.260mm-1、h4＝6.61、h6＝0.85に変化し、
これらの特性値をもつ屈折率分布型レンズの軸上
収差は第７図のように正の軸上収差に転換してい
ることが光線追跡の結果、明らかにされた。尚、
第６図及び第７図のグラフの縦軸はレンズ半径ro
とレンズ中心軸から光線入射位置までの距離をrio
との比である。Example 1 Na 2 O 10%, Tl 2 O 10%, B 2 O 3 20 in molar percentages
%, SiO 2 60% glass was melted to create a glass rod with a diameter of 3 mm. This was immersed in a potassium nitrate melt kept at 530°C for 608 hours, and the
Tl + ions and Na + ions are exchanged with K + ions in the melt, and after processing, it is cut into a predetermined length and both end faces are polished to parallel planes, and the parameters are no = 1.605, g = 0.274 mm.
-1 , h4 = 1.50, and h6 = -99.2, a lens body was obtained. Using the above characteristic values, we used the ray tracing method to determine the focal point of parallel rays incident at various positions on one end surface after exiting from the other end surface, and determined the axial aberration. As a result, we found negative axial aberration as shown in Figure 6. It was confirmed that it has Therefore, as a result of annealing this lens body in air at 540°C for 450 hours, the refractive index gradient in the region relatively near the periphery became gentler, and the parameters of the refractive index distribution were g = 0.260 mm -1 and h 4 = 6.61. , h 6 =0.85,
As a result of ray tracing, it was revealed that the axial aberration of the gradient index lens having these characteristic values was converted into a positive axial aberration as shown in FIG. still,
The vertical axis of the graphs in Figures 6 and 7 is the lens radius ro.
and the distance from the lens center axis to the ray incident position is r io
This is the ratio of
このレンズ内の光線の蛇行ピツチＰはＰ＝
2π／ｇ＝23.3mmであるのでレンズの長さをＰ／４
以内の5.00mmに切り一端から波長λ＝0.63μｍの
平行光を入射したところ出射端より約0.52mmの位
置にパワーがほぼガウス分布状のスポツトを結び
その１／e2のパワーの拡りは2.0μｍであり、この
時のレンズの明るさはNA＝0.30であつた。次に
このレンズの出射端を曲率半径ζ＝3r0＝３×３
＝９mmで凸の球面加工したところ、ガウス分布状
の出射スポツトの１／e2の拡りが1.4μｍに減少
し、かつNAを0.45に高めることが出来た。 The meandering pitch P of the light ray inside this lens is P=
2π/g=23.3mm, so the length of the lens is P/4
When a parallel beam of wavelength λ = 0.63 μm is input from one end to 5.00 mm, the power will form a spot approximately 0.52 mm from the output end with a nearly Gaussian distribution, and the power spread will be 1/e 2 The diameter of the lens was 2.0 μm, and the brightness of the lens at this time was NA=0.30. Next, set the exit end of this lens to the radius of curvature ζ=3r 0 =3×3
When a convex spherical surface was machined with = 9 mm, the 1/e 2 spread of the Gaussian distribution-like emission spot was reduced to 1.4 μm, and the NA was able to be increased to 0.45.
実施例 ２
実施例１と同様にして第６図に示す負の軸上収
差をもちパラメータがn0＝1.605、ｇ＝0.274mm-1、
h4＝1.50、h6＝−99.2で表わされる直径３mmのロ
ツドレンズを製作し、これを空気中で540℃、260
時間焼鈍した後、屈折率分布のパラメータを測定
したところｇ＝0.270mm-1、h4＝1.90、h6＝−55.0
であり、光線追跡の結果、軸上収差は第８図に示
すように中心から外周までほぼゼロに近い均等な
分布となり、本発明に係る焼鈍処理がレンズ周辺
部の収差補正に大きな効果のあることが確認され
た。Example 2 Similar to Example 1, it had the negative axial aberration shown in FIG. 6, and the parameters were n 0 = 1.605, g = 0.274 mm -1 ,
A rod lens with a diameter of 3 mm expressed by h 4 = 1.50 and h 6 = -99.2 was manufactured, and it was heated in air at 540°C and 260°C.
After time annealing, the parameters of the refractive index distribution were measured: g = 0.270 mm -1 , h 4 = 1.90, h 6 = -55.0
As a result of ray tracing, the axial aberration has a uniform distribution close to zero from the center to the outer periphery, as shown in Figure 8, indicating that the annealing treatment according to the present invention is highly effective in correcting aberrations in the peripheral area of the lens. This was confirmed.
なお、上記のレンズの開口数（NA）は0.30で
出射スポツトのパワーの拡がりは1.6μｍであつ
た。 The numerical aperture (NA) of the above lens was 0.30, and the power spread of the exit spot was 1.6 μm.
第１図はタイプのガラス組成のレンズ素材を
イオン交換処理した場合における処理時間と軸上
収差△ｓとの関係を示すグラフ、第２図はタイプ
のガラス組成のレンズ素材をイオン交換処理し
た場合における処理時間と軸上収差△ｓとの関係
を示すグラフ、第３図ａはタイプのガラスによ
る屈折率分布型レンズの収差の状態を示す側面
図、第３図ｂはタイプのガラスによる屈折率分
布型レンズの収差の状態を示す側面図、第４図は
タイプガラスのレンズの屈折率分布を示すグラ
フ、第５図はタイプガラスのレンズの屈折率分
布を示すグラフ、第６図は本発明に係るレンズ素
材のイオン交換後の軸上収差の一例を示すグラ
フ、第７図は第６図例のレンズ体に実施例１の条
件で焼鈍を施した後の軸上収差の状態を示すグラ
フ、第８図は第６図例のレンズ体に実施例２の条
件で焼鈍を施した後の軸上収差の状態を示すグラ
フである。
Figure 1 is a graph showing the relationship between processing time and axial aberration Δs when a lens material with a type of glass composition is subjected to ion exchange treatment, and Figure 2 is a graph showing a relationship between ion exchange treatment and a lens material with a type of glass composition. A graph showing the relationship between processing time and axial aberration Δs in Figure 3a is a side view showing the aberration state of a gradient index lens due to different types of glass, Figure 3b is a graph showing the relationship between processing time and axial aberration Δs. A side view showing the state of aberration of the distributed type lens, Fig. 4 is a graph showing the refractive index distribution of the type glass lens, Fig. 5 is a graph showing the refractive index distribution of the type glass lens, and Fig. 6 is the present invention. FIG. 7 is a graph showing an example of the axial aberration after ion exchange of the lens material according to the above, and FIG. 7 is a graph showing the state of the axial aberration after the lens body of the example shown in FIG. , FIG. 8 is a graph showing the state of axial aberration after annealing the lens body of the example shown in FIG. 6 under the conditions of Example 2.
Claims (1)
Na2O5〜17％、Tl2O3〜15％を主成分とするガラ
スのロツドをイオン交換媒体中でイオン交換処理
してガラスロツド内に中心から外側に向けて連続
的に変化する屈折率分布を与え、しかる後、この
ガラスロツドを、該ガラスとの間で実質的にイオ
ン交換を生じない加熱媒体中において前記ガラス
の転移温度域で熱処理することを特徴とする屈折
率分布型レンズの製造方法。 ２ モル百分率でSiO257〜63％、B2O317〜23％、
Na2O5〜17％、Tl2O3〜15％を主成分とするガラ
スのロツドをイオン交換媒体中でイオン交換処理
してガラスロツド内に中心から外側に向けて連続
的に変化する屈折率分布を与え、しかる後、この
ガラスロツドを、該ガラスとの間で実質的にイオ
ン交換を生じない加熱媒体中において前記ガラス
の転移温度域で熱処理し、得られたガラスロツド
の少なくとも片端面を所定曲率の凸曲面に加工す
ることを特徴とする屈折率分布型レンズの製造方
法。[Claims] 1. SiO 2 57-63%, B 2 O 3 17-23% in molar percentage,
A glass rod whose main components are Na2O5 ~17% and Tl2O3 ~15% is treated with ion exchange in an ion exchange medium to create a refractive index distribution that changes continuously from the center to the outside within the glass rod. A method for producing a gradient index lens, which comprises applying a glass rod to the glass rod, and then heat-treating the glass rod in a heating medium that does not substantially cause ion exchange with the glass in the transition temperature range of the glass. 2 SiO 2 57-63%, B 2 O 3 17-23% in molar percentage,
A glass rod whose main components are Na2O5 ~17% and Tl2O3 ~15% is treated with ion exchange in an ion exchange medium to create a refractive index distribution that changes continuously from the center to the outside within the glass rod. After that, this glass rod is heat-treated in the transition temperature range of the glass in a heating medium that does not substantially cause ion exchange with the glass, and at least one end surface of the obtained glass rod is formed into a convex shape having a predetermined curvature. A method for manufacturing a gradient index lens characterized by processing it into a curved surface.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6196281A JPS57179055A (en) | 1981-04-24 | 1981-04-24 | Manufacture of refractive index distribution type lens |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6196281A JPS57179055A (en) | 1981-04-24 | 1981-04-24 | Manufacture of refractive index distribution type lens |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57179055A JPS57179055A (en) | 1982-11-04 |
| JPS6363502B2 true JPS6363502B2 (en) | 1988-12-07 |
Family
ID=13186313
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6196281A Granted JPS57179055A (en) | 1981-04-24 | 1981-04-24 | Manufacture of refractive index distribution type lens |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57179055A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002365251A (en) * | 2001-06-07 | 2002-12-18 | Nippon Sheet Glass Co Ltd | Microchemical system |
| US7057729B2 (en) | 2002-05-30 | 2006-06-06 | Nippon Sheet Glass Co., Ltd. | Photothermal conversion spectroscopic analysis method, and photothermal conversion spectroscopic analysis apparatus for carrying out the method |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59131543A (en) * | 1983-01-17 | 1984-07-28 | Nippon Sheet Glass Co Ltd | Manufacture of index gradient-type lens |
| US4886538A (en) * | 1987-07-28 | 1989-12-12 | Polaroid Corporation | Process for tapering waveguides |
| JP2003104748A (en) * | 2001-09-28 | 2003-04-09 | Fujikura Ltd | Method for manufacturing gradient index lens |
| US10442730B2 (en) * | 2013-11-25 | 2019-10-15 | Corning Incorporated | Method for achieving a stress profile in a glass |
-
1981
- 1981-04-24 JP JP6196281A patent/JPS57179055A/en active Granted
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002365251A (en) * | 2001-06-07 | 2002-12-18 | Nippon Sheet Glass Co Ltd | Microchemical system |
| US7057729B2 (en) | 2002-05-30 | 2006-06-06 | Nippon Sheet Glass Co., Ltd. | Photothermal conversion spectroscopic analysis method, and photothermal conversion spectroscopic analysis apparatus for carrying out the method |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57179055A (en) | 1982-11-04 |
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