Illumination device and method for laser projector

DETAILED DESCRIPTION One or more of the problems outlined above may be solved by the various embodiments of the invention.
The present invention performs a similar function as a lenslet array optical system, but does so more effectively, with fewer and lower cost components, and with improved design flexibility.
The present techniques may be applied to many types of illumination sources such as arc lamps and LED's in addition to lasers.
Broadly speaking, the invention comprises a system and method for converting a laser beam having a non-uniform profile into a source of illumination which has uniform power density.
The generated illumination image may be used for a variety of purposes.
For example, the image may be a uniformly intense rectangle suitable for use in a display device, or it may be a round dot suitable for transmitting the light into an optical fiber.
The present invention can be used to conserve the power generated by the laser source and direct substantially all of the power into the desired illumination region.
Laser speckle artifacts can also be reduced or eliminated at the same time.
The choice of design of the elements in the system allows for precise control of the illumination pattern and the particular telecentric cone angle patterns exiting the illumination pattern.
While the preferred embodiment uses a laser source, the system is capable of utilizing a wide variety of light source devices, including all arc lamps and LED sources.
The operation of a system in accordance with one embodiment of the invention is as follows.
A block diagram of the system is shown in FIG.
4.
A beam of light is first generated by the laser light source.
The light beam is expanded or sized to illuminate a controlled angle diffuser.
The expanded beam remains collimated.
The expanded beam is passed through a controlled angle diffuser (e.
g.
, hologram, bulk scatterer, etc.
) to diffract or direct the light in a predetermined pattern.
(Crossed lenticular arrays, or lenslet arrays can also be used