−13− AGC Research Report 69 (2019) 散乱光の光弾性効果を用いたガラスの 応力測定装置の開発 Development of the stress meter in glass material using photo-elastic effect of scattering light 馬田 拓実*・折原 秀治**・稲葉 誠二*・大神 聡司***・今北 健二* Takumi Umada, Shuji Orihara, Seiji Inaba, Satoshi Ohgami and Kenji Imakita スマートフォンなどのモバイル電子機器のカバーガラスとして、化学強化により圧縮応力を導入 したガラスが多く使用されている。近年、リチウムアルミノケイ酸塩系ガラスにLi→Na置換、そ の後にNa→K置換を施す2段化学強化ガラスが主流になってきている。しかし、Li→Na置換層の 圧縮応力を、非破壊かつ簡便に測定する方法は存在しなかった。 そこで、ガラス中を透過するレーザの散乱光の光弾性効果を利用し、Li→Na置換層の圧縮応力 を測定する装置SLP-1000を開発した。本装置により、特にガラス表面から50μm以上深い領域の 圧縮応力を、非破壊かつ簡便に測定することが可能になった。しかし、SLP-1000はSN比が不足す るという課題を抱えていたため、光源波長の短波長化など光学系を改良したSLP-2000を試作した。 SLP-2000は、SLP-1000に比べSN比が3倍程度良く、Li→Na置換層の圧縮応力を測定するのに非常 に適していると考えられる。 Glass materials with compressive stress introduced by chemical strengthening, such as cover glass on mobile electronic devices (e.g., smartphones), are widely used. In recent years, the lithium alumino-silicate glass, which is chemically strengthened with Li → Na and then Na → K substitution, has become popular. However, there was no convenient and non- destructive method available to measure the compressive stress of the Li → Na substitution layer. Therefore, we developed SLP-1000, a device to measure the compressive stress of the Li → Na substitution layer, by utilizing the photo-elastic effect of the scattered light of the laser beam that passes through the glass. This device enabled us to conveniently measure the compressive stress without destructions and, particularly, in a region deeper than 50μm from the glass surface. However, since the SLP-1000 device features poor SN ratio, we developed a prototype of SLP-2000, with improved optical systems, such as the shorter wavelength of the light source. SN ratio of SLP-2000 was three times better than that of SLP- 1000, and it was considered as suitable for measuring the compressive stress of the Li → Na substitution layer. *AGC株式会社 技術本部 材料融合研究所 ([email protected]) **有限会社折原製作所 ***AGC株式会社 電子カンパニー 先進機能ガラス事業本部
7
Embed
Z«w« Q®L ;Mh¨åµw ÷ w C Development of the stress meter in ... · µ µ "($3FTFBSDI3FQPSU ¢ £ Z«w« Q®L ;Mh¨åµw ÷ w C Development of the stress meter in glass material
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
−13−
AGC Research Report 69(2019)
散乱光の光弾性効果を用いたガラスの応力測定装置の開発
Development of the stress meter in glass material using photo-elastic effect of scattering light
Glass materials with compressive stress introduced by chemical strengthening, such as cover glass on mobile electronic devices (e.g., smartphones), are widely used. In recent years, the lithium alumino-silicate glass, which is chemically strengthened with Li → Na and then Na → K substitution, has become popular. However, there was no convenient and non-destructive method available to measure the compressive stress of the Li → Na substitution layer. Therefore, we developed SLP-1000, a device to measure the compressive stress of the Li → Na substitution layer, by utilizing the photo-elastic effect of the scattered light of the laser beam that passes through the glass. This device enabled us to conveniently measure the compressive stress without destructions and, particularly, in a region deeper than 50μm from the glass surface. However, since the SLP-1000 device features poor SN ratio, we developed a prototype of SLP-2000, with improved optical systems, such as the shorter wavelength of the light source. SN ratio of SLP-2000 was three times better than that of SLP-1000, and it was considered as suitable for measuring the compressive stress of the Li → Na substitution layer.