Light source device, image display device, projector, illumination device, and monitor device

A light source device that generates irradiation light that is irradiated onto a predetermined face, the light source device comprising:

• a laser light source that emits laser light;
• a diffractive optical element that is located between the laser light source and the predetermined face, and that diffracts the laser light;
• a diffusion optical element that is located between the laser light source and the predetermined face, that is located between the diffractive optical element and the predetermined face, that has both an incidence face into which the laser light is incident and which has a shape that controls the direction of travel of the laser light so that the post-incident laser light travels toward a light emission face, and the light emission face from which the laser light from the incidence face is emitted, and that diffuses the laser light by refracting the laser light at the incidence face, wherein
• the laser light from the diffractive optical element is incident into the incidence face of the diffusion optical element.

A light source device that generates irradiation light that is irradiated onto a predetermined face, the light source device comprising:

• a laser light source that emits laser light;
• a diffractive optical element that is located between the laser light source and the predetermined face, and that diffracts the laser light;
• and
• a diffusion optical element that is located between the laser light source and the predetermined face, that is located between the diffractive optical element and the predetermined face, that has an incidence face into which the laser light is incident and a light emission face from which the laser light from the incidence face is emitted, and that diffuses the laser light, wherein
• unit structures that include at least one of recessed portions and protruding portions whose surfaces are shaped as curved surfaces and that are two-dimensionally arrayed on at least one of the incidence face and the light emission face of the diffusion optical element, and
• the laser light from the diffractive optical element is incident into the incidence face of the diffusion optical element.