RETROREFLECTIVE SHEET

PROBLEM TO BE SOLVED: To provide a retroreflective sheet that can reduce the generation of light in rainbow colors and suppress a reduction in resolution when used for a three-dimensional image projection system.SOLUTION: A retroreflective sheet comprises a sheet-like substrate part, and a plurality of retroreflective elements 22 that are formed on one face of the substrate part. The retroreflective elements 22 each have three reflection side surfaces 22a, 22b, and 22c that share one apex, and the reflection side surfaces 22a, 22b, and 22c adjacent to each other share ridge lines 26 extending from the apex 24. In plan view, of valley lines 28x, 28y, and 28z formed between the retroreflective elements 22 adjacent to each other, at least part of the valley lines 28x, 28y, and 28z are parallel to each other, and the standard deviation of the pitches of the plurality of parallel valley lines 28x, 28y, and 28z is 3 μm or more.SELECTED DRAWING: Figure 1 【課題】虹色の光の発生や３次元画像投射システムに用いられる場合における解像度の低下を抑制することができる再帰反射シートを提供する。【解決手段】シート状の支持体部と、支持体部の一方の面に形成される複数の再帰反射素子２２と、を備え、それぞれの再帰反射素子２２は、一つの頂点を共有する３つの反射側面２２ａ，２２ｂ，２２ｃを有し、頂点２４から延在する稜線２６を互いに隣り合う反射側面２２ａ，２２ｂ，２２ｃで共有し、平面視において互いに隣り合う再帰反射素子２２の間に形成される複数の谷線２８ｘ，２８ｙ，２８ｚのうち少なくとも一部の谷線２８ｘ，２８ｙ，２８ｚは互いに平行であり、平行な複数の谷線２８ｘ，２８ｙ，２８ｚのピッチの標準偏差が３μｍ以上である。【選択図】図１