JP4842424B2

JP4842424B2 - Method for measuring and evaluating skin texture, and use of a composition that exhibits effectiveness by the method

Info

Publication number: JP4842424B2
Application number: JP2000245331A
Authority: JP
Inventors: 明大岡田; 義史小川
Original assignee: Naris Cosmetics Co Ltd
Current assignee: Naris Cosmetics Co Ltd
Priority date: 2000-07-07
Filing date: 2000-07-07
Publication date: 2011-12-21
Anticipated expiration: 2020-07-07
Also published as: JP2002017689A

Description

【０００１】
【発明の属する技術分野】
この発明は、皮膚の質感の評価法ならびに該評価法を用いる前記質感を若くみせる組成物のスクリーニング法、及び該スクリーニング法により選択された組成物を含有する化粧料に関するものである。
【０００２】
【従来の技術】
女性が肌を若々しくみせたいという願いは普遍的である。この様な欲求を満たすために様々な化粧料が開発されてきた。
【０００３】
人が肌の若さを視覚的に評価する場合、「色」、「形態」、及び「質感」の視点から総合的に判断している。
【０００４】
「色」及び「形態」については、加齢に伴う黄みの増加、赤みの減少、明度の減少が、また、シワやたるみの増加が主観的にも客観的にも明らかにされている。更に、分光反射率の測定や皮膚レプリカの画像解析など十分に確立された系から、それら視点についての肌の若さに対する科学的な理論や評価法を構築し、製品研究が為されている。例えば、鈴木一弘と松枝明、１９９６−２、ＦＲＡＧＲＡＮＣＥＪＯＵＲＮＡＬ、ｐ３５〜４０によると、皮膚の分光反射率を測定し、皮膚色のくすみの原因は赤色波長の６４０ｎｍ以上の反射率の低下によるものであり、その帯域の分光透過率を上げた粉体配合の化粧料により健康的な皮膚色を演出することが可能であると報告されている。また、特開平２−２４６８３３号公報には、皮膚のレプリカ撮影画像を階調処理及び画像処理して皮溝の深さを得る方式が、特開平７−２３１８８３号公報には、皮膚を明暗強調撮影装置により直接撮影し、皮膚表面の微細明暗分布が強調された二次元画像を得て、更にその画像の加工処理により、皮膚の光学的美しさと相関する皮膚表面の凹凸の粗さや明度分布の均一性を得る方式が開示されている。
【０００５】
「質感」については、「色」や「形態」ほど多くの知見は得られていない。質感という言葉は国語辞典（岩波国語辞典第五版）によると、「材料の性質の違いから受ける感じ、材料が持っている感じ」の意味を示す。布施学と新本浩一、１９９９、Ｊ．Ｓｏｃ．Ｃｏｓｍｅｔ．Ｃｈｅｍ．Ｊｐｎ．、Ｖｏｌ．３３、Ｎｏ．２、ｐ１５４〜１６２によると、質感の測定は一般的には光学的になされることが多く、物体の表面反射光成分の強弱で評価され、その表面反射光成分には表面の凹凸情報や光沢情報が含まれていると報告されている。
【０００６】
特開平１０−６２３３８号公報には、角層の半透明性に由来する光学効果に着目し、異なる２方向（８５度と４０度）からの照射光に対する分光反射率を複数測定し、得られたスペクトルパターンを相互比較することで、皮膚を美しくみせる化粧料の評価法として確立できることが開示されている。また、小島伸俊ら、１９９３、５６巻、４号、ｐ２６４〜２６９には、皮膚の表面反射光成分のフーリエ解析による毛穴等の凹凸情報の定量化が報告されている。
【０００７】
しかし、これらの測定法及び評価法を実施するためには、高額な測定・解析機器の購入、複雑で手間の掛かる手順、専門的な知識などが要求され、充分な汎用性、利便性までには至っていない。特に、皮膚の「質感」においては、簡易な測定法が未充足であり、しかも、加齢に伴う皮膚の質感の変化は殆ど解明されていない。また更に、肌の若さに対する科学的な理論や評価法の構築、及びそれらに基づく製品研究もあまり為され得ないのが現状である。
【０００８】
即ち、人の肌を視覚的に評価する場合の主要な視点の一つである質感について、その測定法を確立し、それを活用し若くみせる理論を明らかにし、評価法を開発することが求められていた。
【０００９】
【発明が解決しようとする課題】
本発明はこのような状況を踏まえて為されたものである。皮膚の質感、つまりは皮膚の凹凸情報や光沢の変化が客観的かつ、簡易な方法で測定できれば、例えば、皮膚の質感を若くみせる手段を構築するのに資し、化粧料選択の基準として資することも可能である。したがって、本発明の目的は、皮膚の質感の簡易な測定法を確立し、それにより若くみせる理論を明らかにし、評価法を提供することにある。
【００１０】
【課題を解決するための手段】
このような状況に鑑みて、本発明者等は人の皮膚が若くみえる光学的メカニズムを解明すべく鋭意研究を重ねた結果、人の皮膚の質感が回復し皮膚が若くみえる大きな要素の一つに、皮膚に対する光源の入射角とその表面反射光成分の受光角の組み合わせに光学的要素が存在することを見出した。
【００１１】
皮膚の凹凸情報に関して、加齢に伴い、皮膚真皮における構造線維の変化や崩壊、皮下脂肪の厚さの減少により、皮膚が弛緩し、大小様々なしわが目立ち、毛穴が大きく縦に垂れてくるなどの状態が見られる。
【００１２】
加齢に伴い、皮丘の不均一化、面積増加、ふっくら感の減少が生じ、細胞レベルでも皮膚の老化角質細胞は偏平化を来す。そのため、皮膚の光沢に関しては、皮脂量が減少しているにもかかわらず、視覚的に皮膚表面上では光沢が顕著にみられ、素肌において、いわゆる、皮膚のテカリが観察される。若い世代の皮膚においても、光沢が観察されるが、均一で面積の小さいふっくらした皮丘や適度な透明性のある角層であるため半透明性をもった美しい光沢が観察される。つまり、同じ光学現象を観察していても、両者間においては皮膚の光沢感の傾向は異なり、その差異が、中高年齢の場合は、所謂、「テカリ」と、若い年齢の場合は、「つや」と表現されている。
【００１３】
本発明者等は、皮膚の質感を照射光による皮膚表面反射光成分から検討した。特に、若い世代の「つや」と中高年の「テカリ」の差異について、照射光の入射角と表面反射光成分の受光角とが同じ組み合わせの場合でも、若い皮膚と中高年の皮膚とではその反射光成分の強度が異なることを見出した。さらには、光源の入射角と受光角の組み合わせを変化させ皮膚の表面反射光成分を多面的に観察することから、ある特異的な入射角と受光角における表面反射光成分が若くて美しく見えることに大きく寄与することを見出した。
【００１４】
したがって、本発明によれば、皮膚の質感の評価法であって、若い被験者の皮膚を対照とし、被験者の皮膚表面に対する照射光の入射角が２０〜７０度である場合、皮膚表面に対する受光角が反射方向４０〜７０度の表面反射光成分に、差異がみられることを前記質感の老化度合いの指標とする、方法が提供される。
【００１５】
またさらに本発明方法によれば、皮膚の質感を回復または若くみせ得る組成物の簡易な評価法、特に、光学機能的組成物のスクリーニング法も提供できる。具体的には、被検組成物を前記皮膚の質感の評価法にかける被験者に適用し、その適用の前記質感への有効性を評価することにより、皮膚の質感を回復または若くみせる組成物がスクリーニングできる。
【００１６】
【発明の実施の形態】
以下に本発明の実施形態を図面に基づいて説明する。最も好ましい形態としては、次ぎに示す手順に従って行われる。
【００１７】
１）皮膚表面に、拡散光を一方向から照射し、偏光板の装着された銀塩カメラ又は電子的カメラ何れかの撮影装置にて前記皮膚表面を複数の受光角度で撮影する。ここで撮影する皮膚表面の部位は特に限定されないが、顔全体又は人の頬の撮影が適切な評価結果が得られることから好ましい。受光角度は、前記皮膚表面に対して前記照射光の入射方向と反対方向に０〜８０度、より好ましくは２０〜８０度、更に好ましくは４０〜７０度である。その際、偏光板の回転により皮膚の内部反射光成分を含む表面反射光成分を最も強調した写真、並びに皮膚の表面反射光成分を最も除去した写真をそれぞれ撮影する。拡散光源は特に限定されないが、好ましくは白色白熱光である。また、撮影装置は得られる写真が銀塩カメラあるいは電子的カメラの何れかを活用してもよいが、好ましくはＣＣＤカメラ又は非ＣＣＤカメラを撮像部とするデジタルカメラである。デジタルカメラでは、写真の解析手順を短絡化でき、また、より適切な評価結果が得られる。本発明者等はデジタルカメラＣ−２５００Ｌ（ＯＬＹＭＰＵＳ社製）を用いた。
【００１８】
２）１）の方向とは異なる角度で前記拡散光を照射し、同様に皮膚の内部反射光成分を含む表面反射光成分を最も強調した写真、並びに皮膚の表面反射光成分を最も除去した写真をそれぞれ１）と同様に受光角度を変化させ複数撮影する。これらの撮影は、複数回、各々異なる角度の拡散光照射で行う。このとき、１）と２）の照射する光の皮膚表面に対する入射角は、０〜８０度、より好ましくは２０〜８０度、更に好ましくは２０〜７０度である。
【００１９】
３）１）の前記皮膚の内部反射光成分を含む表面反射光成分を最も強調した写真並びに皮膚の表面反射光成分を最も除去した写真をそれぞれデジタル変換した後、両者の差分処理により表面反射光成分画像を得る。同様に２）の前記皮膚の内部反射光成分を含む表面反射光成分を最も強調した写真並びに皮膚の表面反射光成分を最も除去した写真についても同様に行い表面反射光成分画像を得る。ここで、写真のデジタル変換にはデジタル変換可能ならば行う機器は限定されない。本発明者等はデジタルカメラを用いているので当該手順は省略した。
【００２０】
４）前記表面反射光成分画像を２５６階調の輝度値（Ｌ^＊値）に変換し、輝度レベルを増幅した。変換する際の階調は、１２８、６４、３２などでも構わないが、２５６がより好ましい。その輝度値が皮膚の質感の指標となる。このとき増幅の倍率は１〜５、より好ましくは１．５〜４、更に好ましくは２〜３．５である。また、３）の差分処理、並びに４）の輝度変換及び増幅処理には各処理が可能ならば特に限定されないが、本発明者等は画像編集ソフトであるＰｈｏｔｏｓｈｏｐ３．０Ｊ（Ａｄｏｂｅ社製）を用いた。ここで、皮膚の表面反射光成分を検出する方法として前記１）〜４）の手順を行ったが、表面反射光成分の検出が可能であるなら特に限定されない。
【００２１】
５）かくして得られた様々な組み合わせをもつ皮膚の表面反射光成分の傾向から皮膚の質感を評価する。特に、照明光の皮膚表面に対する入射角が２０〜７０度で、受光角度が入射方向と反対方向の４０〜７０度で測定した表面反射光成分について質感の評価を行うのがより好ましい。
【００２２】
また、アンケートにより客観的に若い肌にみえると評価された２０歳未満の被験者の測定データを対照とし、測定した２０歳以上の表面反射光成分のデータを比較することで、皮膚の質感の老化度合いを評価することができる。
【００２３】
さらに本発明によれば、光学的機能をもった組成物を被験者の測定部位に適用し、それらによる皮膚の質感への有効性を評価することにより、皮膚の質感の回復または若くみえることに役立ち得るかを評価することができる。この評価方法によれば、ある一定の組成物が皮膚の質感の老化を回復させる、または若くみせる作用を有するか、否かが評価でき、皮膚を視覚的に若くみせるのに有用な組成物をスクリーニングできる。
【００２４】
本発明によれば、こうしてスクリーニングされる組成物を皮膚を視覚的に若くみせるための有効成分として使用する化粧料にも提供できる。
【００２５】
本発明者らは皮膚の質感を若くみせる素材を鋭意研究した結果、かかる化粧料の一例として、塗布される皮膚温度下においても粘度低下を起こさず適度な膜厚を保持し、自然な透明性があり、更に、塗布表面上における表面反射光成分を拡散させる架橋型メチルポリシロキサンとメチルポリシロキサンからなるシリコーンゲル組成物と異なる３つ以上の成分からなる多層型板状粉体を含有する化粧料に光学的な効果を見出している。
【００２６】
シリコーンゲル組成物は架橋型メチルポリシロキサンとメチルポリシロキサンからなる組成物〔例えば信越化学工業株式会社製のＤＮ−１９６〕が特に好ましいが、塗布する皮膚温下において適度な膜厚を保持するのであるならば、限定されない。シリコーンゲル組成物の本発明の化粧料における好ましい含有量は、５〜７５重量％が好ましく、更に好ましくは１０〜６５重量％である。
【００２７】
多層型板状粉体は、屈折率の高い板状のセリサイトを核として、酸化チタン、酸化アルミニウム、シリカの屈折率の高い順にコーティングした粉体〔例えば触媒化成工業株式会社製のＣＯＶＥＲＬＥＡＦＡＲ−２０１２１Ｍ〕が、特開平１１−３４９４４２号公報にて報告されているような多成分からなる球状の多層型粉体よりも、皮膚の質感を若くみせるには特に好ましいが、膜厚の保持、適度な光拡散性及び半透膜性があるならば、限定されない。多層型板状粉体の本発明の化粧料における好ましい含有量は、３〜３０重量％が好ましく、更に好ましくは５〜２０重量％である。
【００２８】
したがって、本発明に従う有効成分として、架橋型メチルポリシロキサンとメチルポリシロキサンからなるシリコーンゲル組成物と異なる３つ以上の成分からなる多層型板状粉体を含有する化粧料は、特に、加齢に基づく皮膚の質感の老化に起因する老いてみえる皮膚の処置に適する。
【００２９】
【実施例】
以下、本発明を具体的に挙げてさらに詳細に説明する。
【００３０】
例１：年齢的な皮膚の見え方の違いにおける質感の評価
図１には前記手順で得た人の顔の表面反射光成分の入射角受光角の組み合わせ例を示している。光源の入射角は顔面正面に対して０、２２．５、４５、６７．５度のそれぞれで照射し、撮影装置の受光角は前記顔面表面に対して反射方向に正の角度を表すとし、０、２２．５、４５、６７．５度とした。照射光の入射角６７．５度で受光角を０、２２．５、４５、６７．５度のそれぞれにした場合を１に、照射光の入射角４５度で受光角０、２２．５、４５、６７．５度のそれぞれにした場合を２に、照射光の入射角２２．５度で受光角０、２２．５、４５、６７．５度のそれぞれにした場合を３に、照射光の入射角０度で受光角２２．５、４５、６７．５度のそれぞれにした場合を４に示した。これら１５の入射角受光角の組み合わせから、顔の表面反射光成分を多面的に測定することができる。
【００３１】
【図１】
【００３２】
被験者の肌が老いてみえるのか若くみえるのかは、アンケートにより客観的に判定した。アンケートは「▲１▼頬のくすみが少ない」、「▲２▼頬につや感がある」、「▲３▼頬にうるおい感がある」、及び「▲４▼頬にはり感がある」の４項目について、「全く感じない」を１、「非常にはっきりと感じる」を７として最も該当するところをチェックさせる７段階評価を用いた。評価は第三者の視覚による主観的な観察により行った。若くみえるか、否かの判定基準はアンケートで得られる４項目の評点を数１に代入し、肌の老若ポイントを算出した。このポイントは、０以上の場合を若くみえるとし、ポイントが高いほどより肌が若くみえると評価でき、逆に、０未満の場合を老いて見えるとし、ポイントが低いほどより肌が老いてみえると客観的に評価できる。
【００３３】
【数１】
【００３４】
図２及び図３は、図１で示された１５の入射角受光角の組み合わせで前記１）〜４）の手順により測定した場合の表面反射成分の図で、図２はアンケートよるポイントが１．２５で若くみえると判定された２０歳女性の顔全体の質感の傾向を示し、図３はポイントが−１．３３で年老いてみえると判定された４８歳女性の顔の質感の傾向を示す。横軸は照射光の顔面表面に対する入射角で６７．５、４５、２２．５、０度と順に示し、縦軸は撮影装置の受光角で顔面表面に対する反射方向を正とし、６７．５、４５、２２．５、０度と順に示す。輝度変換後の増幅は３倍である。輝度が高く、より白く見える部分ほど光沢があることを示す。
【００３５】
【図２】
【００３６】
【図３】
【００３７】
図２と図３を比較した場合、６７．５度入射６７．５度受光、４５度入射６７．５度受光、２２．５度入射６７．５度受光、４５度入射４５度受光各々にて、年老いてみえると判定された女性の方が若くみえると判定された女性よりも輝度が高く、白く見える部分が多く観察される。このことから、年老いて見えると判定された女性には特異的な入射角受光角の組み合わせにおいて顕著な光沢が見受けられる、と判断できる。また、凹凸情報から観察できるしわに関しても、年老いて見えると判定された女性の方が目立って観察されている。
【００３８】
図４及び図５は、図２及び図３それぞれに関して、左頬の部位のみトリミングし、図示したものである。頬のトリミングは、人が肌の老若を評価する際、主に頬の部位を重点に置き判断していることが明らかとなっているため、特に、この部位に関して検討した。
【００３９】
【図４】
【００４０】
【図５】
【００４１】
図４と図５を比較した場合、６７．５度入射６７．５度受光、４５度入射６７．５度受光、２２．５度入射６７．５度受光、４５度入射４５度受光各々にて年老いて見えると判定された女性の方が若くみえると判定された女性よりも輝度が高く白く見える部分が多く観察される。このことから、年老いて見えると判定された女性には特異的な入射角受光角の組み合わせにおいて顕著な光沢が見受けられる、と判断できる。また、凹凸に関しても、年老いて見えると判定された女性の方が目立って観察されている。
【００４２】
つまり、６７．５度入射６７．５度受光、４５度入射６７．５度受光、２２．５度入射６７．５度受光、４５度入射４５度受光の４組または何れか１組以上における皮膚の光沢を減少させ、目立ったしわをぼかせば、皮膚の老いた質感に関して若くみせることが可能となることが判る。したがって、これらの入射角受光角の組み合わせについて、２０歳未満のアンケート等により肌が若いと判定された被験者を対照として、被験者の表面反射光成分を比較することで、皮膚の質感の老化度合いを評価することができる。
【００４３】
例２：質感における光沢の数値化
実施例１の被験者２名に加え、アンケートにより肌が若いと評価されている対照女性被験者２名、同様に肌が年老いていると評価された女性被験者２名を用いて、図１の入射角受光角の組み合わせにおける素肌状態の頬及び顔全体の表面反射成分を、前記１）〜４）の手順に基づき測定した。輝度変換後の増幅倍率は３倍とした。
【００４４】
光沢度合いの数値化は、頬をトリミングし、そのエリア内の各画素の輝度値に関して行った。被験者毎でエリアの総画素数が異なるので、各輝度値の画素数を対総画素数比で表した。数２により、対照女性を含む各被験者の皮膚の光沢の明るさを数値化した。数２のＫは輝度値を、Ｐｋは輝度値Ｋの対総画素数比を表す。
【００４５】
【数２】
【００４６】
実施例１の図４及び図５の光沢度の数値結果を表１に示す。表１は、図４及び図５の表面反射光成分に関して光沢度合いを数値化し、表に示したものである。また表中の「６７入６７受」は６７．５度入射６７．５度受光を示す。「６７入４５受」は６７．５度入射４５度受光を示す。「６７入２２受」は６７．５度入射２２．５度受光を示す。「６７入０受」は６７．５度入射０度受光を示す。「４５入６７受」は４５度入射６７．５度受光を示す。「４５入４５受」は４５度入射４５度受光を示す。「４５入２２受」は４５度入射２２．５度受光を示す。「４５入０受」は４５度入射０度受光を示す。「２２入６７受」は２２．５度入射６７．５度受光を示す。「２２入４５受」は２２．５度入射４５度受光を示す。「２２入２２受」は２２．５度入射２２．５度受光を示す。「２２入０受」は２２．５度入射０度受光を示す。「０入６７受」は０度入射６７．５度受光を示す。「０入４５受」は０度入射４５度受光を示す。「０入２２受」は０度入射２２．５度受光を示す。表１と図４及び図５から光沢度合いの数値化が適正に行われていることが確認できる。また、６７．５度入射６７．５度受光、４５度入射６７．５度受光、２２．５度入射６７．５度受光、４５度入射４５度受光の４組についての光沢度合いに関して、老いてみえる肌（Ｂ）と若くみえる肌（Ａ）との差（Ｂ）−（Ａ）は何れも正の値であり、しかも、老いた肌の光沢度合いが約３．５倍ほど大きく、対照女性者に比して被験女性者の皮膚の質感老化が進行していると評価することができる。
【００４７】
【表１】

【００４８】
さらに、実施例１の被験者も加えた対照群及び年老いた群、それぞれ３名ずつにおける、皮膚の光沢度合いの平均値の結果を図６に示す。白抜き丸印は対照、黒四角印は年老いた被験者である。図中のｘ軸の「６７入６７受」等は表１と同様に６７．５度入射６７．５度受光を示す。
【００４９】
【図６】
【００５０】
図６から、６７．５度入射６７．５度受光、４５度入射６７．５度受光、２２．５度入射６７．５度受光、４５度入射４５度受光において、肌が老いている被験者の光沢度合いが対照の若い被験者よりも、大きな値を示しており、数値データからも、皮膚の質感の老化が進んでいることが評価できる。
【００５１】
例３：皮膚の質感を若くみせる処方例
表２に示す組成に関して、成分（１）〜（８）を混合、さらに成分（９）〜（１１）を混合したものを加え、ホモミキサーにて均一に混合分散し、質感回復化粧料を得た。実施例、並びに比較例１、２、及び３の化粧料を用い、製品の効果を官能評価及び本発明における評価法により検討した。比較例１及び２の多層型球状粉体は球状シリカに酸化チタン、シリカを順次コーティングした３層からなる球状物である。
【００５２】
【表２】

【００５３】
１９及び２０歳の女性３名に対し、【００３１】で記載したアンケートならびに【数１】から老若ポイント算出し、最もポイントの大きい女性被験者を対照者とした（老若ポイントは１．２１）。同様に４０〜５０歳の女性３名対し、最も老若ポイントが小さい女性被験者を試験者とした（老若ポイントは−１．５５）。図１の入射角受光角の組み合わせにおける素肌状態の頬及び顔全体の表面反射成分を、前記１）〜４）の手順に基づき、化粧料塗布前と化粧料塗布後の皮膚の質感を測定し、対照者との比較により化粧料による試験者の皮膚の質感への影響を評価した。
【００５４】
図７に結果を示す。図７には、若くみえる肌と老いてみえる肌とを比較した場合に特異的な質感の差異がみられる「６７．５度入射６７．５度受光、４５度入射６７．５度受光、２２．５度入射６７．５度受光、４５度入射４５度受光」の４つの組み合わせにおいての表面反射光成分を示している。
【００５５】
【図７】
【００５６】
対照者においては、比較例１、比較例２、比較例３、及び実施例の塗布によっても、皮膚の光沢度合いや凹凸度合いは塗布前とは殆ど変化していないことが明らかである。一方、試験者においては、皮膚の光沢度は実施例塗布において、塗布前に比して光沢度が減少し、凹凸度合いも軽減されていることが明らかに判る。また、対照者の質感の傾向にも近づいており、皮膚の質感が回復していることが判る。比較例１、比較例２、及び比較例３塗布においては、あまり皮膚の質感に影響を及ぼさず質感の回復は得られていない。
【００５７】
表３には図７に関して左頬の部位だけをトリミングし、実施例２記載の方法により数値化したものである。まず、無塗布時の若くみえる肌と老いてみえる肌の差（Ｂ）−（Ａ）が、特異的な質感の差異がみられる「６７．５度入射６７．５度受光、４５度入射６７．５度受光、２２．５度入射６７．５度受光、４５度入射４５度受光」の４つの組み合わせにおいて何れもの正であることから、対照者に比して試験者の皮膚の質感は老化が進行していると評価された。
【００５８】
また、対照者（Ａ）においては、実施例塗布によっても無塗布時である塗布前との差（Ｄ）−（Ｃ）が負の値を示し、質感に有効ではなく、比較例１、２及び３に至っては、更に小さな値を示し、逆に皮膚の質感老化が促進されてみえると評価された。一方、試験者（Ｂ）においては、実施例塗布での差（Ｄ）−（Ｃ）がいずれの４つの組合わせにおいても、正であり、しかも、比較例１、２、及び３に比して大きな値を示し、皮膚の質感老化の回復に最も有効であると評価された。
【００５９】
【表３】

【００６０】
官能評価は専門パネラー１０名により行った。アンケートは総合的な評価として「仕上がりが自然で若くみえる」、質感の評価として「凹凸が自然に消える」、「光沢度合いが自然にみえる」の３項目について、「全く感じない」を１、「非常にはっきりと感じる」を７として最も該当するところをチェックさせる７段階評価を用いた。結果の平均点を表４に示す。表４から、試験例において、総合的にも仕上がりがよく、また質感の回復にも有効であり、実際の見た目にも皮膚の質感が若くみえていることが明らかに確認される。
【００６１】
【表４】

【００６２】
なお、本発明は上記実施形態に限定されるものではなく、本発明の範囲内で上記実施形態に多くの修正及び変更を加え得ることは勿論である。
【００６３】
【発明の効果】
本発明によると、皮膚の質感、つまりは、皮膚の凹凸情報や光沢度合いを客観的に、かつ簡易に測定することができる。また、若くみせるための質感に関する光学的理論に基づく評価法が提供される。これらは、加齢による皮膚の質感の老化に関して、肌を視覚的に若くみせるための有効な素材選択に利用できる。
【００６４】
【図面の簡単な説明】
【図１】図１は、照射光である光源の入射角と、それに対する撮影装置の受光角との組み合わせの一例である。
【図２】図２は、アンケートにより若くみえると判定された２０歳女性の顔全体の表面反射光成分を示す図。
【図３】図３は、アンケートにより年老いてみえると判定された４８歳女性の顔全体の表面反射光成分を示す図。
【図４】図４は、図２から頬の部位のみをトリミングした場合の表面反射光成分を示す図。
【図５】図５は、図４から頬の部位のみをトリミングした場合の表面反射光成分を示す図。
【図６】図６は、アンケートにより若くみえると判定された対照女性被験者及び年老いてみえると評価された女性被験者においての頬の表面反射成分を数値化した図。
【図７】図７は、本発明の評価法により有効性を示す表面反射光成分のデータである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a skin texture evaluation method, a screening method for a composition that makes the texture younger using the evaluation method, and a cosmetic containing a composition selected by the screening method.
[0002]
[Prior art]
The desire for women to make their skin look youthful is universal. Various cosmetics have been developed to satisfy such needs.
[0003]
When a person visually evaluates skin youth, a comprehensive judgment is made from the viewpoints of “color”, “form”, and “texture”.
[0004]
Regarding “color” and “morphology”, an increase in yellowness, a decrease in redness, and a decrease in lightness with aging, and an increase in wrinkles and sagging are revealed both subjectively and objectively. Furthermore, scientific theories and evaluation methods for skin youth from these viewpoints have been established from well-established systems such as spectral reflectance measurement and skin replica image analysis, and product research is being conducted. For example, according to Kazuhiro Suzuki and Akira Matsuda, 1996-2, FRAGRANANCE JOURNAL, p35-40, the spectral reflectance of the skin is measured, and the cause of dull skin color is due to a decrease in the reflectance of 640 nm or more of the red wavelength. It is reported that it is possible to produce a healthy skin color by using a powder-containing cosmetic with an increased spectral transmittance in the band. Japanese Patent Laid-Open No. 2-246833 discloses a method of obtaining a depth of the skin groove by performing gradation processing and image processing on a replica image of the skin, and Japanese Patent Laid-Open No. 7-231883 emphasizes light and darkness of the skin. Photographed directly with a photographing device to obtain a two-dimensional image in which the fine light and dark distribution on the skin surface is emphasized, and further processing the image to obtain roughness and lightness distribution on the surface of the skin that correlates with the optical beauty of the skin. A method for obtaining the uniformity of the above is disclosed.
[0005]
As for “texture”, as much knowledge as “color” and “form” has not been obtained. According to the Japanese dictionary (Iwanami Japanese Dictionary 5th edition), the word “texture” means “feeling from the difference in the properties of the material, the feeling that the material has”. Manabu Fuse and Koichi Niimoto, 1999, J. Am. Soc. Cosmet. Chem. Jpn. Vol. 33, no. 2, according to p154 to 162, the texture is generally measured optically, and is evaluated by the intensity of the surface reflected light component of the object. The surface reflected light component includes surface unevenness information and glossiness. Information is reported to be included.
[0006]
Japanese Patent Laid-Open No. 10-62338 is obtained by paying attention to the optical effect derived from the translucency of the stratum corneum and measuring a plurality of spectral reflectances with respect to irradiation light from two different directions (85 degrees and 40 degrees). It is disclosed that it can be established as a method for evaluating cosmetics that make the skin look beautiful by comparing the spectral patterns. Further, Kojima Nobutoshi et al., 1993, Volume 56, No. 4, pp. 264 to 269 report quantification of unevenness information such as pores by Fourier analysis of the surface reflected light component of the skin.
[0007]
However, in order to carry out these measurement methods and evaluation methods, purchase of expensive measurement / analysis equipment, complicated and time-consuming procedures, specialized knowledge, etc. are required. Has not reached. In particular, for the “texture” of the skin, a simple measurement method is unsatisfactory, and changes in the texture of the skin with aging are hardly elucidated. Furthermore, there are currently few scientific theories and evaluation methods for skin youth and product research based on them.
[0008]
In other words, it is necessary to establish a measurement method for texture, which is one of the main viewpoints when visually evaluating human skin, to clarify the theory of making it younger and to develop an evaluation method. It was done.
[0009]
[Problems to be solved by the invention]
The present invention has been made in view of such a situation. If the texture of the skin, that is, changes in skin roughness and gloss, can be measured objectively and in a simple manner, it will contribute to, for example, the creation of a means to make the skin texture younger and serve as a basis for selecting cosmetics. It is also possible. Therefore, an object of the present invention is to establish a simple method for measuring the texture of the skin, thereby clarifying the theory of making it younger, and to provide an evaluation method.
[0010]
[Means for Solving the Problems]
In view of these circumstances, the present inventors have conducted extensive research to elucidate the optical mechanism that makes human skin look younger. As a result, the texture of human skin is restored and is one of the major factors that make skin look younger. Furthermore, the present inventors have found that there is an optical element in the combination of the incident angle of the light source with respect to the skin and the light receiving angle of the surface reflected light component.
[0011]
Regarding skin unevenness information, with aging, structural fibers change and collapse in the dermis, the thickness of the subcutaneous fat decreases, the skin relaxes, large and small wrinkles are noticeable, pores droop large and vertically, etc. Can be seen.
[0012]
As the skin ages, the skin becomes uneven, the area increases, and the fluffy sensation decreases. Even at the cellular level, aging keratinocytes of the skin become flattened. Therefore, regarding the gloss of the skin, the gloss is visually noticeable on the surface of the skin despite the decrease in the amount of sebum, and so-called skin shine is observed on the bare skin. Gloss is also observed in younger generations of skin, but beautiful luster with translucency is observed due to the fluffy skin with a uniform and small area and a moderately transparent stratum corneum. In other words, even when the same optical phenomenon is observed, the tendency of the glossiness of the skin is different between the two, and the difference is so-called “shine” for middle-aged and older, and “shiny” for younger age. "Is expressed.
[0013]
The present inventors examined the texture of the skin from the reflected light component on the skin surface by irradiation light. In particular, regarding the difference between the younger generation “Tsuya” and the middle-aged “Tecari”, even if the incident angle of the irradiated light and the light-receiving angle of the surface reflected light component are the same combination, the reflected light between the young skin and the middle-aged skin We found that the strength of the components was different. Furthermore, since the surface reflection light component of the skin is observed from multiple angles by changing the combination of the incident angle and the light reception angle of the light source, the surface reflection light component at a specific incident angle and light reception angle must be young and beautiful. It has been found that it contributes greatly.
[0014]
Therefore, according to the present invention, there is provided a skin texture evaluation method, in which the skin angle of a young subject is used as a control, and when the incident angle of the irradiation light with respect to the skin surface of the subject is 20 to 70 degrees, the light receiving angle with respect to the skin surface A method is provided in which a difference in surface reflected light components in the reflection direction of 40 to 70 degrees is used as an indicator of the degree of aging of the texture.
[0015]
Furthermore, according to the method of the present invention, it is possible to provide a simple evaluation method for a composition capable of restoring or rejuvenating the skin texture, particularly a screening method for an optical functional composition. Specifically, a composition that restores or rejuvenates the skin texture by applying the test composition to a subject subjected to the skin texture evaluation method and evaluating the effectiveness of the application to the texture. Can be screened.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. As the most preferable mode, it is carried out according to the following procedure.
[0017]
1) The skin surface is irradiated with diffused light from one direction, and the skin surface is photographed at a plurality of light receiving angles with a photographing device of either a silver salt camera or an electronic camera equipped with a polarizing plate. The part of the skin surface to be imaged here is not particularly limited, but imaging of the entire face or a person's cheek is preferable because an appropriate evaluation result can be obtained. The light receiving angle is 0 to 80 degrees, more preferably 20 to 80 degrees, still more preferably 40 to 70 degrees in the direction opposite to the incident direction of the irradiation light with respect to the skin surface. At that time, a photograph in which the surface reflection light component including the internal reflection light component of the skin is most emphasized by rotation of the polarizing plate and a photograph in which the surface reflection light component of the skin is most removed are taken. The diffuse light source is not particularly limited, but is preferably white incandescent light. The photographing apparatus may use either a silver salt camera or an electronic camera as a photograph to be obtained, but is preferably a digital camera having a CCD camera or a non-CCD camera as an imaging unit. With a digital camera, the photo analysis procedure can be short-circuited, and more appropriate evaluation results can be obtained. The inventors used a digital camera C-2500L (manufactured by OLYMPUS).
[0018]
2) A photograph in which the diffused light is irradiated at an angle different from the direction of 1), and the surface reflection light component including the internal reflection light component of the skin is similarly emphasized, and a photograph in which the surface reflection light component of the skin is most removed. In the same manner as 1), a plurality of images are taken by changing the light receiving angle. These photographing operations are performed a plurality of times by diffusing light irradiation at different angles. At this time, the incident angle with respect to the skin surface of the light irradiated by 1) and 2) is 0 to 80 degrees, more preferably 20 to 80 degrees, and still more preferably 20 to 70 degrees.
[0019]
3) After digitally converting the photograph in which the surface reflected light component including the internal reflected light component of the skin in 1) is emphasized and the photograph in which the surface reflected light component in the skin is most removed, the surface reflected light is subjected to differential processing between the two. A component image is obtained. Similarly, the surface reflected light component image is obtained in the same manner for the photograph 2) where the surface reflected light component including the internal reflected light component of the skin is most emphasized and the photograph where the surface reflected light component of the skin is most removed. Here, the apparatus for performing digital conversion of photographs is not limited as long as digital conversion is possible. Since the present inventors use a digital camera, the procedure is omitted.
[0020]
4) The surface reflected light component image was converted to a luminance value (L ^* value) of 256 gradations, and the luminance level was amplified. The gradation for conversion may be 128, 64, 32, etc., but 256 is more preferable. The luminance value becomes an index of the texture of the skin. At this time, the amplification factor is 1 to 5, more preferably 1.5 to 4, and still more preferably 2 to 3.5. Further, the difference processing of 3) and the luminance conversion and amplification processing of 4) are not particularly limited as long as each processing is possible, but the present inventors have used Photoshop 3.0J (manufactured by Adobe) as image editing software. Using. Here, the procedure of 1) to 4) was performed as a method for detecting the surface reflected light component of the skin, but there is no particular limitation as long as the surface reflected light component can be detected.
[0021]
5) The texture of the skin is evaluated from the tendency of the surface reflected light component of the skin having various combinations thus obtained. In particular, it is more preferable to evaluate the texture of the surface reflected light component measured when the incident angle of the illumination light with respect to the skin surface is 20 to 70 degrees and the light receiving angle is 40 to 70 degrees opposite to the incident direction.
[0022]
In addition, aging of the texture of the skin is made by comparing the measured data of the surface reflected light components over 20 years old with the measurement data of subjects under 20 years old evaluated as objectively looking young skin by the questionnaire The degree can be evaluated.
[0023]
Furthermore, according to the present invention, by applying a composition having an optical function to a measurement site of a subject and evaluating the effectiveness of the composition on the skin texture, it helps to restore the skin texture or make it look younger. You can evaluate whether you get. According to this evaluation method, it is possible to evaluate whether or not a certain composition has an action of restoring or rejuvenating the skin texture, and a composition useful for visually rejuvenating the skin is obtained. Can be screened.
[0024]
According to the present invention, the composition thus screened can also be provided for a cosmetic that is used as an active ingredient for making the skin visually young.
[0025]
As a result of diligent research on materials that make the skin feel younger, the present inventors, as an example of such cosmetics, maintain an appropriate film thickness without causing a decrease in viscosity even under the applied skin temperature, and have natural transparency. And further comprising a multi-layer plate-like powder comprising three or more components different from a silicone gel composition comprising cross-linked methylpolysiloxane and methylpolysiloxane that diffuses the surface reflected light component on the coated surface An optical effect is found in the material.
[0026]
The silicone gel composition is particularly preferably a composition comprising cross-linked methylpolysiloxane and methylpolysiloxane (for example, DN-196 manufactured by Shin-Etsu Chemical Co., Ltd.), because it maintains an appropriate film thickness at the applied skin temperature. If there is, it is not limited. The preferable content of the silicone gel composition in the cosmetic of the present invention is preferably 5 to 75% by weight, more preferably 10 to 65% by weight.
[0027]
The multilayer plate-like powder is a powder in which titanium oxide, aluminum oxide and silica are coated in descending order of the refractive index of plate-like sericite having a high refractive index (for example, COVERLEAF AR- manufactured by Catalyst Chemical Industry Co., Ltd.). 20121M] is particularly preferable for making the skin feel younger than the multi-component spherical multi-layered powder as reported in JP-A-11-349442. As long as the light diffusibility and the semipermeable membrane are present, there is no limitation. The content of the multilayer plate-like powder in the cosmetic of the present invention is preferably 3 to 30% by weight, more preferably 5 to 20% by weight.
[0028]
Therefore, as an active ingredient according to the present invention, a cosmetic containing a multilayer plate-like powder composed of three or more components different from a silicone gel composition composed of cross-linked methylpolysiloxane and methylpolysiloxane is particularly aged. Suitable for the treatment of aging skin caused by aging of the skin texture.
[0029]
【Example】
Hereinafter, the present invention will be specifically described in detail.
[0030]
Example 1: Evaluation of texture according to age-related difference in skin appearance FIG. 1 shows a combination example of incident angles and light receiving angles of surface reflected light components of a human face obtained by the above procedure. The incident angle of the light source is irradiated at 0, 22.5, 45, and 67.5 degrees with respect to the front of the face, and the light receiving angle of the photographing device represents a positive angle in the reflection direction with respect to the face surface, The angles were 0, 22.5, 45, and 67.5 degrees. When the incident angle of irradiation light is 67.5 degrees and the reception angle is 0, 22.5, 45, and 67.5 degrees, respectively, the incident angle of irradiation light is 45 degrees and the reception angles are 0, 22.5, Irradiation light is set to 2 when the angle is 45 and 67.5 degrees, and 3 when the incident angle is 22.5 degrees and the receiving angles are 0, 22.5, 45, and 67.5 degrees. The case where the incident angle is 0 degree and the light receiving angles are 22.5, 45, and 67.5 degrees is shown in FIG. The face reflection light component of the face can be measured in a multifaceted manner from the combination of these 15 incident angles and light receiving angles.
[0031]
[Figure 1]
[0032]
Whether the subject's skin looks old or young was determined objectively by a questionnaire. The questionnaires are “▲ 1 ▼ Cheeks are less dull”, “▲ 2 ▼ Cheeks are glossy”, “▲ 3 ▼ Cheeks are moist”, and “4) Cheeks are sticky” For the four items, a 7-step evaluation was used in which the most applicable place was checked, with 1 being “not felt at all” and 7 being “feeling very clearly”. The evaluation was performed by subjective observation by a third party. The criteria for determining whether to look younger were obtained by substituting the scores of the four items obtained in the questionnaire into Equation 1, and calculating the skin age points. If the score is 0 or more, it can be evaluated that the skin looks younger as the point is higher, and conversely, if the score is lower than 0, the skin looks older. It can be evaluated objectively.
[0033]
[Expression 1]
[0034]
2 and 3 are diagrams of surface reflection components when measured by the procedures of 1) to 4) with the combination of 15 incident angles and light receiving angles shown in FIG. 1, and FIG. .20 shows the trend of the overall texture of the face of a 20-year-old woman determined to appear young at 25, and FIG. 3 shows the trend of the texture of the face of a 48-year-old woman determined to appear aged at a point of −1.33. . The horizontal axis indicates the incident angle of the irradiated light with respect to the face surface in the order of 67.5, 45, 22.5, and 0 degree, and the vertical axis indicates the light receiving angle of the photographing apparatus with the reflection direction with respect to the face surface being positive, 67.5, It is shown in order of 45, 22.5, and 0 degrees. Amplification after luminance conversion is 3 times. The brighter the higher the brightness, the brighter the part.
[0035]
[Figure 2]
[0036]
[Fig. 3]
[0037]
When comparing FIG. 2 with FIG. 3, 67.5 degrees incident 67.5 degrees received light, 45 degrees incident 67.5 degrees received light, 22.5 degrees incident 67.5 degrees received light, 45 degrees incident 45 degrees received light respectively A woman who is judged to be aged is brighter than a woman who is judged to be younger, and many parts that appear white are observed. From this, it can be determined that a woman who is determined to be aged appears to have a remarkable gloss in a combination of specific incident angle and light receiving angle. In addition, wrinkles that can be observed from the unevenness information are conspicuously observed for women who are judged to be aged.
[0038]
FIGS. 4 and 5 show only the left cheek region trimmed with respect to FIGS. 2 and 3, respectively. The cheek trimming has been examined especially with regard to this part, since it is clear that a person mainly judges the part of the cheek when evaluating skin age.
[0039]
[Fig. 4]
[0040]
[Figure 5]
[0041]
When FIG. 4 is compared with FIG. 5, 67.5 degrees incident 67.5 degrees received light, 45 degrees incident 67.5 degrees received light, 22.5 degrees incident 67.5 degrees received light, 45 degrees incident 45 degrees received light respectively Many women appear brighter and whiter than women who are judged to look younger than women who are judged to be older. From this, it can be determined that a woman who is determined to be aged appears to have a remarkable gloss in a combination of specific incident angle and light receiving angle. Concerning unevenness, women who are judged to be aged are conspicuously observed.
[0042]
That is, the skin in four sets of 67.5 degree incident 67.5 degree light reception, 45 degree incidence 67.5 degree light reception, 22.5 degree incidence 67.5 degree light reception, 45 degree incidence 45 degree light reception, or any one or more sets It can be seen that by reducing the gloss of the skin and blurring the noticeable wrinkles, it is possible to make the skin look younger. Therefore, with respect to the combination of the incident angle and the light receiving angle, by comparing the surface reflected light component of the subject with a subject whose skin is determined to be young by a questionnaire or the like under 20 years old, the degree of aging of the texture of the skin can be determined. Can be evaluated.
[0043]
Example 2: Quantification of gloss in texture In addition to the two subjects of Example 1, two control female subjects whose skin was evaluated as young by a questionnaire and two female subjects who were similarly evaluated as having an old skin 1 was used to measure the surface reflection components of the bare cheeks and the entire face in the combination of the incident angle and the light receiving angle in FIG. 1 based on the procedures of 1) to 4). The amplification factor after luminance conversion was set to 3 times.
[0044]
The numerical value of the glossiness was obtained by trimming the cheek and regarding the luminance value of each pixel in the area. Since the total number of pixels in the area is different for each subject, the number of pixels of each luminance value is expressed as a ratio of the total number of pixels. According to Equation 2, the brightness of the gloss of each subject including the control woman was quantified. In Equation 2, K represents the luminance value, and Pk represents the ratio of the luminance value K to the total number of pixels.
[0045]
[Expression 2]
[0046]
The numerical results of the glossiness of FIG. 4 and FIG. 5 of Example 1 are shown in Table 1. Table 1 shows the degree of gloss for the surface reflected light components of FIGS. 4 and 5 in numerical form. In the table, “67 input 67 reception” indicates 67.5 degree incidence and 67.5 degree light reception. “67 in 45” indicates 67.5 ° incident 45 ° light reception. “67 input 22 reception” indicates 67.5 degree incident 22.5 degree light reception. “67 input 0 reception” indicates 67.5 degree incident 0 degree light reception. “45 input 67 reception” indicates light reception of 45 ° incidence 67.5 °. “45 in 45” indicates 45 ° incident 45 ° light reception. “45 in 22 receiving” indicates 45 ° incident 22.5 ° light reception. “45 input 0 received” indicates 45 ° incident 0 ° received light. “22 input 67 reception” indicates light reception of 27.5 degrees and 67.5 degrees. “22 in 45 receiving” indicates light receiving at 22.5 degrees and 45 degrees. “22 input 22 reception” indicates 22.5 degree incident 22.5 degree light reception. “22 input 0 reception” indicates 22.5 ° incidence 0 ° light reception. “0 input 67 reception” indicates light reception of 67.5 degrees with 0 degree incidence. “0 input 45 received” indicates 0 degree incident 45 degree received light. “0 insertion 22 reception” indicates light reception at 0 degree incidence and 22.5 degrees. It can be confirmed from Table 1 and FIGS. 4 and 5 that the glossiness is digitized appropriately. Also, regarding the glossiness of the four sets of 67.5 degree incident 67.5 degree light reception, 45 degree incidence 67.5 degree light reception, 22.5 degree incidence 67.5 degree light reception, and 45 degree incidence 45 degree light reception, The difference between the visible skin (B) and the younger skin (A) (B)-(A) is a positive value, and the gloss level of the old skin is about 3.5 times larger. It can be evaluated that the aging of the skin texture of the female subject is progressing compared to the elderly.
[0047]
[Table 1]

[0048]
Furthermore, the result of the average value of the glossiness degree of the skin in each of the control group and the aged group to which the subject of Example 1 was added is shown in FIG. Open circles are controls, and black squares are older subjects. In the figure, “67 input 67 reception” on the x-axis indicates 67.5 degree incident 67.5 degree light reception as in Table 1.
[0049]
[Fig. 6]
[0050]
From FIG. 6, in the case of 67.5 degree incident 67.5 degree light reception, 45 degree incidence 67.5 degree light reception, 22.5 degree incidence 67.5 degree light reception, 45 degree incidence 45 degree light reception, The gloss level is larger than that of the young test subject, and it can be evaluated from the numerical data that the skin texture is aging.
[0051]
Example 3: Formulation Example for Making Skin Texture Younger Regarding the composition shown in Table 2, the components (1) to (8) were mixed, and the components (9) to (11) were further mixed, and homogenized with a homomixer. The material was mixed and dispersed to obtain a texture restoration cosmetic. Using the cosmetics of Examples and Comparative Examples 1, 2, and 3, the effects of the products were examined by sensory evaluation and the evaluation method of the present invention. The multilayered spherical powders of Comparative Examples 1 and 2 are spherical products composed of three layers obtained by coating spherical silica with titanium oxide and silica sequentially.
[0052]
[Table 2]

[0053]
For three 19- and 20-year-old women, the young and old points were calculated from the questionnaire described in ## EQU1 ## and ## EQU1 ## and the female subject with the largest point was used as the control (old and young points were 1.21). Similarly, for three women aged 40 to 50 years, the female subject with the smallest age point was the tester (the age point was -1.55). Based on the procedure of 1) to 4), the texture of the skin before and after the cosmetic application is measured for the surface reflection components of the cheek and the entire face in the combination of the incident angle and the light reception angle of FIG. The effect of cosmetics on the skin texture of the tester was evaluated by comparison with the control.
[0054]
The results are shown in FIG. In FIG. 7, there is a specific difference in texture when comparing skin that looks young and skin that looks old. “67.5 degrees incident 67.5 degrees received light, 45 degrees incident 67.5 degrees received light, 22 The surface reflected light components in the four combinations of “.5.degree. Incident 67.5.degree. Light reception and 45.degree. Incidence 45.degree. Light reception" are shown.
[0055]
[Fig. 7]
[0056]
In the control, it is clear that the gloss level and the unevenness level of the skin are hardly changed from those before application even by application of Comparative Example 1, Comparative Example 2, Comparative Example 3, and Example. On the other hand, the tester clearly shows that the glossiness of the skin is reduced in the application of the example compared to before application, and the unevenness is reduced. In addition, it is close to the tendency of the texture of the contrast, and it can be seen that the texture of the skin is recovered. In application of Comparative Example 1, Comparative Example 2, and Comparative Example 3, the texture of the skin is not affected so much and the recovery of the texture is not obtained.
[0057]
In Table 3, only the part of the left cheek is trimmed with respect to FIG. 7, and numerical values are obtained by the method described in Example 2. First, the difference (B)-(A) between the skin that looks young and the skin that looks aged when not applied is a specific texture difference. “67.5 ° incidence 67.5 ° light reception, 45 ° incidence 67” .5 degree light reception, 22.5 degree incidence 67.5 degree light reception, 45 degree incidence 45 degree light reception ”is positive in any combination, so the skin texture of the tester is aged compared to the control person Was rated as progressing.
[0058]
Further, in the control person (A), the difference (D)-(C) from the non-application time, which is not applied even in the application of the example, shows a negative value, which is not effective for the texture. And 3, it was evaluated that it showed a smaller value, and conversely, the skin texture aging seemed to be promoted. On the other hand, in the tester (B), the difference (D) − (C) in the application of the example is positive in any of the four combinations, and compared with the comparative examples 1, 2, and 3. It was evaluated to be the most effective in the recovery of skin texture aging.
[0059]
[Table 3]

[0060]
The sensory evaluation was performed by 10 expert panelists. The questionnaire has a comprehensive evaluation of "I feel the finish is natural and youthful", and the texture is an evaluation of "I don't feel at all" for the three items of "Unevenness disappears naturally" and "Glossiness looks natural". A 7-step evaluation was used, where “I feel very clearly” was checked with 7 being the most applicable. The average score of the results is shown in Table 4. From Table 4, it is clearly confirmed that in the test example, the overall finish is good, the texture is effective, and the texture of the skin looks young even in the actual appearance.
[0061]
[Table 4]

[0062]
In addition, this invention is not limited to the said embodiment, Of course, many corrections and changes can be added to the said embodiment within the scope of the present invention.
[0063]
【The invention's effect】
According to the present invention, it is possible to objectively and easily measure the texture of the skin, that is, the unevenness information and the gloss level of the skin. In addition, an evaluation method based on an optical theory relating to the texture to make you look younger is provided. These can be used for effective material selection for making the skin look younger with respect to the aging of the texture of the skin due to aging.
[0064]
[Brief description of the drawings]
FIG. 1 is an example of a combination of an incident angle of a light source that is irradiation light and a light receiving angle of a photographing apparatus with respect to the incident angle.
FIG. 2 is a diagram showing surface reflected light components of the entire face of a 20-year-old woman determined to look younger by a questionnaire.
FIG. 3 is a diagram showing surface reflected light components of the entire face of a 48-year-old woman determined to be aged by a questionnaire.
4 is a diagram showing a surface reflected light component when only a cheek portion is trimmed from FIG. 2; FIG.
FIG. 5 is a diagram showing a surface reflected light component when only a cheek portion is trimmed from FIG. 4;
FIG. 6 is a diagram quantifying the surface reflection component of the cheek in a control female subject judged to look young by a questionnaire and a female subject evaluated to look old.
FIG. 7 is data of a surface reflected light component showing effectiveness by the evaluation method of the present invention.

Claims

1) The skin surface is irradiated with diffused light from one direction, and the skin surface is imaged at a plurality of light receiving angles with an imaging device of either a silver salt camera or an electronic camera equipped with a polarizing plate. The light receiving angle is 0 to 80 degrees in the direction opposite to the incident direction of the irradiation light with respect to the skin surface. At this time, a step of taking a photograph in which the surface reflection light component including the internal reflection light component of the skin is most emphasized by rotating the polarizing plate and a photograph in which the surface reflection light component of the skin is most removed.
2) A photograph in which diffused light is irradiated at an angle different from the direction of 1), and the surface reflected light component including the internal reflected light component of the skin is emphasized as well as the photograph in which the surface reflected light component of the skin is most removed. Step of changing the light receiving angle and shooting a plurality of images as in 1). These photographing operations are performed a plurality of times by diffusing light irradiation at different angles. The incident angle with respect to the skin surface of the light irradiated at this time is 0 to 80 degrees.
3) After the digital conversion of the photograph in which the surface reflected light component including the internal reflected light component of the skin of 1) is emphasized and the photograph in which the surface reflected light component of the skin is most removed, respectively, the surface reflected light component is processed by differential processing between the two. Get an image. Similarly, the step of 2) obtaining the surface reflected light component image in the same manner for the photograph in which the surface reflected light component including the internal reflected light component of the skin is most emphasized and the photograph in which the surface reflected light component of the skin is most removed.
4) A step of converting the surface reflected light component image obtained in 3) into a luminance value (L * value) of 256 gradations and amplifying the luminance level.
In the data obtained through the steps 1) to 4), the surface reflected light component at the time of applying the test composition of the subject's skin evaluation site is (C), and the surface reflected light component of the skin evaluation site at the time of non-application is ( D), when the incident angle of the irradiation light is any angle of 20 to 70 degrees with respect to the skin surface, the light receiving angle is any of reflection directions of 40 to 70 degrees with respect to the skin surface. And (D)-(C)> 0 as an index for evaluating the effectiveness of the skin texture.