Laser projection device

Abstract

The invention provides a laser projection device. An incident laser beam is expanded by a front fixed beam expander group, and then the incident laser beam then enters a zoom lens group; the zoom lensgroup selects the diameter of the expanded light beam and transmits the expanded light beam to a compensation lens group; the compensation lens group compensates the light output by the zoom lens group and outputs a collimated light beam; the collimated light beam passes through a focusing lens group to be converged at a rear focal plane of the focusing lens group; light beams diverged by a random phase plate positioned on the rear focal plane are collimated by a rear fixed collimating lens group to enter a fixed collimating lens group, and expanded collimated light beams are output through the rear fixed collimating lens group. According to the laser projection device provided by the invention, the refocused light beams after beam expansion can be gathered into a smaller focus which canbe approximately regarded as a standard focus of a rear collimating lens group, the random phase plate is placed at the position of the focus point to play the roles of dodging and speckle elimination, and so the continuous zoom beam expansion, collimation, dodging and speckle elimination are realized.

Description

technical field [0001] The invention relates to the technical field of laser display, in particular to a laser projection device. Background technique [0002] Laser has the characteristics of directivity, good coherence and high brightness, and is widely used in projection display, projection lithography lighting system and other fields. In particular, the laser projection lithography illumination system in the field of micro-nano processing has high requirements on the uniformity and collimation of the expanded laser beam. At the same time, due to the coherence of the laser, when the laser passes through components or reaches the display panel, serious speckle noise will be generated due to effects such as reflection, refraction, interference, diffraction and scattering, which seriously affects the quality of lithography. [0003] At present, laser beam expanders have two kinds of laser beam expanders, fixed magnification and variable magnification. The fixed magnificati...

AI Technical Summary

Problems solved by technology

Since the output beam diameter of a general laser is greater than 3mm, it is also difficult to obtain a high-quality uniform collimated beam after passing through a phase photo with a certain divergence angle.

[0004] In the current laser display or projection lithography lighting system, speckle dissipation and uniform light collimation are generally realized by multiple discrete optical components, which have complex and loose structures, poor stability, and high power consumption of the system

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