ILLUMINATION DEVICE AND IMAGE SENSOR

PROBLEM TO BE SOLVED: To provide an illumination device and an image sensor capable of acquiring a high-quality image without changing an illuminance ratio of a terminal part of a light guide body with respect to a central part of the light guide body so much even in the case where a document face distance is changed.SOLUTION: An illumination device includes: a light source 1; a rod-like light guide body 3 in which light made incident from the light source 1 to the inside is propagated while being reflected in a long axis direction; and a reflection pattern 4 that is provided periodically in the long axis direction between one end portion and another end portion of the light guide body 3 on a surface of the light guide body 3. In the process of propagating light in the light guide body 3, the reflection pattern 4 is irradiated with light from the inside of the light guide body 3, and light reflected by the reflection pattern 4 forms a linear emission area at a side that opposes the reflection pattern 4, through the light guide body 3. The reflection pattern 4 includes a protrusion of which the width in the long axis direction is decreased gradually as separated from the surface of the light guide body 3. A cross section of the protrusion in the long axis direction is formed so as to continue a plurality of curved parts and is made asymmetric with respect to a centerline that passes an apex of the protrusion. 【課題】原稿面距離が変化した場合でも導光体の端部の照度比が導光体の中央部に対してあまり変化せず、高品質の画像を取得できる照明装置およびイメージセンサを提供する。【解決手段】照明装置は、光源１と、光源１から内部に入射した光が長軸方向に反射しながら伝播する棒状の導光体３と、導光体３の表面において、導光体３の一端部と他端部との間に長軸方向に沿って周期的に設けられた反射パターン４とを具備する。光が導光体３を伝播する過程において、導光体３の内部から反射パターン４に光が照射され、反射パターン４によって反射した光が導光体３を通して反射パターン４に対向する側にライン状の出射領域を形成する。反射パターン４は、導光体３の表面から遠くなるほど、長軸方向の幅が漸減する突起部を有する。突起部の長軸方向の断面形状は、複数の湾曲部が連続するように形成され、突起部の頂部を通る中心線に関して非対称である。【選択図】図６