Optical diffusion assembly, optical diffusion element and projection device

A projection device, comprising:

• an illumination system, an optical engine module, and a lens, wherein,
• the illumination system is adapted to provide an illumination beam and comprises a light source, an optical diffusion assembly, and a light uniformizing element,
• the light source is adapted to provide a light beam,
• the optical diffusion assembly is disposed a transmission path of the light beam and comprises a first optical body and a second optical body, the light beam sequentially passes through the first optical body and the second optical body,
• the first optical body has a first surface and a second surface opposite to each other,
• the second optical body has a third surface and a fourth surface opposite to each other,
• the first surface or the third surface has a first diffusion region,
• the fourth surface has a second diffusion region, the first diffusion region and the second diffusion region are located on a central optical axis of the light beam,
• a first part of the light beam sequentially passes through the first diffusion region and the second diffusion region, a second part of the light beam passes through the first diffusion region and does not pass through the second diffusion region,
• an orthogonal projection of the first diffusion region on the fourth surface of the second optical body is overlapped with and greater than an orthogonal projection of the second diffusion region on the fourth surface of the second optical body,
• the light uniformizing element is disposed on the transmission path of the light beam transmitted by the optical diffusion assembly and is configured to form the illumination beam,
• the optical engine module is disposed on a transmission path of the illumination beam and comprises a light valve module and an optical prism disposed on the transmission path of the illumination beam and configured to guide the illumination beam to the light valve module and guide an image beam from the light valve module, and
• the lens is disposed on a transmission path of the image beam and is configured to project the image beam out of the projection device.

A projection device, comprising:

• an illumination system, an optical engine module, and a lens, wherein
• the illumination system is adapted to provide an illumination beam and comprises a light source, an optical diffusion element, and a light uniformizing element,
• the light source is adapted to provide a light beam,
• the optical diffusion element is disposed a transmission path of the light beam and is a plano-convex condenser lens,
• the plano-convex condenser lens has a first surface and a second surface opposite to each other,
• the first surface has a first diffusion region, the second surface has a second diffusion region, the first diffusion region and the second diffusion region are located on a central optical axis of the light beam, the first surface further has a third diffusion region, there is a gap between the first diffusion region and the third diffusion region, a first part of the light beam sequentially passes through the first diffusion region and the second diffusion region, a second part of the light beam sequentially passes through the gap and the second diffusion region,
• the light uniformizing element is disposed on the transmission path of the light beam transmitted by the optical diffusion element and is configured to form the illumination beam,
• the optical engine module is disposed on a transmission path of the illumination beam and comprises a light valve module and an optical prism disposed on the transmission path of the illumination beam and configured to guide the illumination beam to the light valve module and guide an image beam from the light valve module, and
• the lens is disposed on a transmission path of the image beam and is configured to project the image beam out of the projection device.