JP2018072420A - lens - Google Patents

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JP2018072420A
JP2018072420A JP2016208502A JP2016208502A JP2018072420A JP 2018072420 A JP2018072420 A JP 2018072420A JP 2016208502 A JP2016208502 A JP 2016208502A JP 2016208502 A JP2016208502 A JP 2016208502A JP 2018072420 A JP2018072420 A JP 2018072420A
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lens
camera
magnetic crystal
crystal
refractive index
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JP2016208502A
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Japanese (ja)
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太志 鈴木
Futoshi Suzuki
太志 鈴木
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Nippon Electric Glass Co Ltd
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Nippon Electric Glass Co Ltd
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Priority to JP2016208502A priority Critical patent/JP2018072420A/en
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Abstract

PROBLEM TO BE SOLVED: To provide a lens easy to downsize a digital camera, a mobile phone with a camera or the like.SOLUTION: A lens consists of magnetic crystal having a refraction index (nd) of 1.80 or more.SELECTED DRAWING: Figure 1

Description

本発明は、カメラのオートフォーカス用レンズ等に好適なレンズに関する。   The present invention relates to a lens suitable for an autofocus lens of a camera.

デジタルカメラやカメラ付携帯電話等には、近接撮影、通常撮影及び遠方撮影を可能にするため、カメラの焦点距離を変える、つまり、オートフォーカス用レンズを所定の位置に移動させるための駆動装置が設けられている。従来、このようなレンズの駆動装置には、レンズを固定するためのレンズホルダー、レンズホルダーを移動させるためのばねが備えられている。   Digital cameras, camera-equipped mobile phones, and the like have a drive device for changing the focal length of the camera, that is, moving the autofocus lens to a predetermined position in order to enable close-up shooting, normal shooting, and distant shooting. Is provided. Conventionally, such a lens driving device is provided with a lens holder for fixing the lens and a spring for moving the lens holder.

しかしながら、上記のような駆動装置は、レンズホルダー、ばねが必要であるため、近年のデジタルカメラやカメラ付携帯電話等の小型化の要求に対応できない。そこで、レンズを磁性ガラスまたは磁性プラスチックにすることにより、磁石によってレンズ自体を移動させる手法が提案されている(特許文献1参照)。   However, since the drive device as described above requires a lens holder and a spring, it cannot meet the recent demand for downsizing of digital cameras, camera-equipped mobile phones and the like. Therefore, a method has been proposed in which the lens itself is moved by a magnet by making the lens magnetic glass or plastic (see Patent Document 1).

特開2004−29668号公報JP 2004-29668 A

しかしながら、ガラス及びプラスチックは屈折率が低いため、デジタルカメラやカメラ付携帯電話等を小型化しにくいという問題がある。   However, since glass and plastic have a low refractive index, there is a problem that it is difficult to miniaturize digital cameras, camera-equipped mobile phones, and the like.

以上に鑑み、本発明は、デジタルカメラやカメラ付携帯電話等を小型化しやすいレンズを提供することを目的とする。   In view of the above, an object of the present invention is to provide a lens that facilitates miniaturization of a digital camera, a mobile phone with a camera, or the like.

本発明のレンズは、屈折率(nd)が1.80以上の磁性結晶からなることを特徴とする。デジタルカメラやカメラ付携帯電話等に使用するレンズとして、屈折率の高い磁性結晶を使用することにより焦点距離が短くなるため、デジタルカメラやカメラ付携帯電話等を小型化しやすい。   The lens of the present invention is characterized by comprising a magnetic crystal having a refractive index (nd) of 1.80 or more. Since a focal length is shortened by using a magnetic crystal having a high refractive index as a lens used for a digital camera, a camera-equipped mobile phone, etc., it is easy to miniaturize a digital camera, a camera-equipped mobile phone, or the like.

本発明のレンズは、波長633nmにおいて光路長1mmでの光透過率が60%以上であることが好ましい。   The lens of the present invention preferably has a light transmittance of 60% or more at an optical path length of 1 mm at a wavelength of 633 nm.

本発明のレンズは、磁性結晶が、Tb系ガーネット結晶であることが好ましい。   In the lens of the present invention, the magnetic crystal is preferably a Tb garnet crystal.

本発明によれば、デジタルカメラやカメラ付携帯電話等を小型化しやすいレンズを提供することができる。   According to the present invention, it is possible to provide a lens that facilitates miniaturization of a digital camera, a camera-equipped mobile phone, or the like.

チョクラルスキー法により磁性結晶を製造するための装置の一実施形態を示す模式的断面図である。It is typical sectional drawing which shows one Embodiment of the apparatus for manufacturing a magnetic crystal by the Czochralski method.

本発明のレンズは、屈折率(nd)が1.80以上であって、1.82以上、1.84以上、1.86以上、特に1.88以上である磁性結晶からなることが好ましい。屈折率が低すぎると、焦点距離が長くなるためデジタルカメラやカメラ付携帯電話等を小型化しにくくなる。なお、レンズ形状は、特に限定されないが、集光能力を考慮すると、両凸形状(例えば球状)、平凸形状、メニスカス形状が好ましい。   The lens of the present invention is preferably made of a magnetic crystal having a refractive index (nd) of 1.80 or more and 1.82 or more, 1.84 or more, 1.86 or more, particularly 1.88 or more. If the refractive index is too low, the focal length becomes long, and it becomes difficult to miniaturize a digital camera, a camera-equipped mobile phone, or the like. The lens shape is not particularly limited, but considering a light collecting ability, a biconvex shape (for example, a spherical shape), a plano-convex shape, and a meniscus shape are preferable.

磁性結晶としては、Tb系ガーネット結晶であることが好ましい。Tb系ガーネット結晶は、屈折率及び光透過性が高いという特徴を有する。Tb系ガーネット結晶としては、TGG(TbGa12)、TSAG(Tb(Sc、Al)12)、TSLAG(Tb(Sc、Lu)Al12)、TAG(TbAl12)等が使用できる。 The magnetic crystal is preferably a Tb garnet crystal. Tb-based garnet crystals are characterized by high refractive index and light transmittance. Examples of Tb-based garnet crystals include TGG (Tb 3 Ga 5 O 12 ), TSAG (Tb 3 (Sc, Al) 5 O 12 ), TSLAG (Tb 3 (Sc, Lu) 2 Al 3 O 12 ), TAG (Tb 3 Al 5 O 12) or the like can be used.

本発明のレンズは、波長300〜1100nmの範囲で良好な光透過性を示す。具体的には、波長633nmにおける光路長1mmでの透過率は60%以上、65%以上、70%以上、75%以上、特に80%以上であることが好ましい。また、波長532nmにおける光路長1mmでの透過率は30%以上、50%以上、60%以上、70%以上、特に80%以上であることが好ましい。さらに、波長1064nmにおける光路長1mmでの透過率は60%以上、70%以上、75%以上、特に80%以上であることが好ましい。   The lens of the present invention exhibits good light transmittance in the wavelength range of 300 to 1100 nm. Specifically, the transmittance at an optical path length of 1 mm at a wavelength of 633 nm is preferably 60% or more, 65% or more, 70% or more, 75% or more, and particularly preferably 80% or more. Further, the transmittance at an optical path length of 1 mm at a wavelength of 532 nm is preferably 30% or more, 50% or more, 60% or more, 70% or more, and particularly preferably 80% or more. Furthermore, the transmittance at an optical path length of 1 mm at a wavelength of 1064 nm is preferably 60% or more, 70% or more, 75% or more, and particularly preferably 80% or more.

図1は、チョクラルスキー法により磁性結晶を作製するための製造装置の一例を示す模式的断面図である。以下、図1を参照しながら、本発明に使用される磁性結晶1の製造方法について説明する。まず、所望の組成になるように調合した原料を坩堝2内に投入した後、高周波コイル3にて加熱することにより、坩堝2内の原料を融解させ、融液4を得る。次に、回転軸5に円柱状のYAG(YAl12)等の種結晶6を固定する。次に、回転軸5を降下させ融液4に種結晶6を接触させた後、種結晶6を1〜100rpmの速度で回転させながら0.1〜100mm/hの速度にて引き上げ、磁性結晶1を製造する。 FIG. 1 is a schematic cross-sectional view showing an example of a production apparatus for producing a magnetic crystal by the Czochralski method. Hereinafter, the manufacturing method of the magnetic crystal 1 used in the present invention will be described with reference to FIG. First, raw materials prepared to have a desired composition are put into the crucible 2, and then heated by the high-frequency coil 3 to melt the raw materials in the crucible 2 to obtain a melt 4. Next, a seed crystal 6 such as columnar YAG (Y 3 Al 5 O 12 ) is fixed to the rotating shaft 5. Next, after rotating the rotating shaft 5 and bringing the seed crystal 6 into contact with the melt 4, the seed crystal 6 is pulled at a speed of 0.1 to 100 mm / h while rotating the seed crystal 6 at a speed of 1 to 100 rpm. 1 is manufactured.

磁性結晶1の作製は、Ar、N、He等の不活性ガス雰囲気下で行うことが好ましい。また、坩堝としては、白金、イリジウム、ロジウム等が使用できる。なお、本発明に使用される磁性結晶1は、上記のチョクラルスキー法以外にもフローティングゾーン法、ブリッジマン法、ゾーンメルト法、水熱合成法等により製造しても構わない。また、多結晶体を焼結することにより、磁性結晶1を製造してもよい。 The production of the magnetic crystal 1 is preferably performed in an inert gas atmosphere such as Ar, N 2 , and He. Moreover, platinum, iridium, rhodium, etc. can be used as a crucible. In addition, you may manufacture the magnetic crystal 1 used for this invention by the floating zone method, the Bridgman method, the zone melt method, the hydrothermal synthesis method etc. besides said Czochralski method. Moreover, you may manufacture the magnetic crystal 1 by sintering a polycrystal.

続いて、磁性結晶1に切削や研磨等の機械加工を施すことにより、本発明のレンズを得ることが出来る。   Subsequently, the lens of the present invention can be obtained by subjecting the magnetic crystal 1 to machining such as cutting or polishing.

以下、本発明を実施例に基づいて説明するが、本発明はこれらの実施例に限定されるものではない。   EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, this invention is not limited to these Examples.

(実施例)
まず、TbGa12の組成になるように調合した原料をプレス成型し、所望の組成になるように調合した原料を用いて、図1に示す装置により以下のようにして磁性結晶を作製した。
(Example)
First, a raw material prepared so as to have a composition of Tb 3 Ga 5 O 12 is press-molded, and a magnetic crystal is formed as follows using the apparatus shown in FIG. 1 using the raw material prepared so as to have a desired composition. Produced.

原料を坩堝内に投入した後、高周波コイルにて加熱することにより、坩堝内の原料を融解させ、融液を得た。次に、回転軸を降下させ融液に種結晶(YAG)を接触させた後、種結晶を10rpmの速度で回転させながら1mm/hの速度にて引き上げ、磁性結晶を製造した。その後、得られた磁性結晶に切削、研磨等の加工を施すことにより、前面曲率半径 10mm、後面曲率半径 10mm、高さ0.5mmの両凸レンズを得た。得られたレンズについて、屈折率、焦点距離を評価した。得られたレンズは、屈折率が1.97と大きく、焦点距離が5.2mmであった。   After putting the raw material into the crucible, the raw material in the crucible was melted by heating with a high frequency coil to obtain a melt. Next, the rotating shaft was lowered to bring the seed crystal (YAG) into contact with the melt, and then the seed crystal was pulled up at a speed of 1 mm / h while rotating at a speed of 10 rpm to produce a magnetic crystal. Thereafter, the obtained magnetic crystal was subjected to processing such as cutting and polishing to obtain a biconvex lens having a front curvature radius of 10 mm, a rear curvature radius of 10 mm, and a height of 0.5 mm. The obtained lens was evaluated for refractive index and focal length. The obtained lens had a large refractive index of 1.97 and a focal length of 5.2 mm.

(比較例)
モル%で、Tb 20%、P 72%、KO 8%になるように原料を調合し、窒素雰囲気中にて白金坩堝を用いて1100〜1400℃で2時間溶融することにより、ガラス融液を得た。次に、ガラス融液を予熱したカーボン型に鋳込み成形し、成形体を得た。その後、得られた成形体に切削、研磨等の加工を施すことにより、実施例と同様の形状のレンズを得た。得られたレンズについて、屈折率、焦点距離を評価した。得られたレンズは、屈折率が1.68と実施例よりも小さく、焦点距離が7.6mmと実施例よりも大きくなった。焦点距離が長くなると、デジタルカメラやカメラ付携帯電話等の小型化が困難である。
(Comparative example)
The raw materials were prepared so as to be 20% Tb 2 O 3 , 72% P 2 O 5 , and 8% K 2 O in mol%, and melted at 1100 to 1400 ° C. for 2 hours using a platinum crucible in a nitrogen atmosphere By doing so, a glass melt was obtained. Next, the glass melt was cast into a pre-heated carbon mold to obtain a molded body. Thereafter, the obtained molded body was subjected to processing such as cutting and polishing to obtain a lens having the same shape as in the example. The obtained lens was evaluated for refractive index and focal length. The obtained lens had a refractive index of 1.68, which was smaller than that of the example, and a focal length of 7.6 mm, which was larger than that of the example. When the focal length becomes long, it is difficult to miniaturize a digital camera, a camera-equipped mobile phone, or the like.

屈折率はヘリウムランプのd線(587.6nm)に対する測定値で示した。   The refractive index is indicated by a measured value with respect to d-line (587.6 nm) of a helium lamp.

焦点距離は、焦点距離測定装置を用いて測定を行った。   The focal length was measured using a focal length measuring device.

1:磁性結晶
2:坩堝
3:高周波コイル
4:融液
5:回転軸
6:種結晶
1: Magnetic crystal 2: Crucible 3: High frequency coil 4: Melt 5: Rotating shaft 6: Seed crystal

Claims (3)

屈折率(nd)が1.80以上の磁性結晶からなることを特徴とするレンズ。   A lens comprising a magnetic crystal having a refractive index (nd) of 1.80 or more. 波長633nmにおいて光路長1mmでの光透過率が60%以上であることを特徴とする請求項1に記載のレンズ。   The lens according to claim 1, wherein the light transmittance at an optical path length of 1 mm at a wavelength of 633 nm is 60% or more. 磁性結晶が、Tb系ガーネット結晶であることを特徴とする請求項1又は2に記載のレンズ。   The lens according to claim 1, wherein the magnetic crystal is a Tb-based garnet crystal.
JP2016208502A 2016-10-25 2016-10-25 lens Pending JP2018072420A (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006251151A (en) * 2005-03-09 2006-09-21 Fuji Photo Film Co Ltd Lens drive and imaging apparatus
JP2007108734A (en) * 2005-09-21 2007-04-26 Schott Ag Optical element and imaging optical element comprising same
WO2015060372A1 (en) * 2013-10-23 2015-04-30 株式会社フジクラ Crystal body, optical device having same and crystal body production method

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006251151A (en) * 2005-03-09 2006-09-21 Fuji Photo Film Co Ltd Lens drive and imaging apparatus
JP2007108734A (en) * 2005-09-21 2007-04-26 Schott Ag Optical element and imaging optical element comprising same
WO2015060372A1 (en) * 2013-10-23 2015-04-30 株式会社フジクラ Crystal body, optical device having same and crystal body production method

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