Illumination device and vehicle lamp

A vehicle lamp comprising an illumination device,

• wherein the illumination device comprises:
• a light source configured to emit excitation light;
• a light guide comprising a first light guiding portion and a second light guiding portion, wherein the second light guiding portion comprises a light emitting surface, the excitation light emitted by the light source is coupled into the first light guiding portion and then emitted through the light emitting surface of the second light guiding portion, a cross section of the second light guiding portion perpendicular to a center line of the light guide has an area gradually decreasing along a direction of an optical axis of the light source, and an intersecting line of the light emitting surface of the second light guiding portion and a cross section passing through the center line of the light guide or each of tangent lines of the intersecting line forms an acute angle with the center line of the light guide, wherein the light emitting surface is provided on a portion of a side surface of the second light guiding portion, and the side surface is directly connected to the first light guiding portion;
• and
• a functional layer which is coated on the light emitting surface of the second light guiding portion, and configured to perform a wavelength conversion on the excitation light or scatter the excitation light.