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CN-121995686-A - Laser projection system, laser speckle suppression method and optical display device

CN121995686ACN 121995686 ACN121995686 ACN 121995686ACN-121995686-A

Abstract

The embodiment of the application provides a laser projection system, a laser speckle suppression method and optical display equipment, wherein the laser projection system comprises a laser light source module, an active electric tuning super-surface device, a control module and an imaging module, the laser light source module is used for providing illumination light beams, the active electric tuning super-surface device is arranged on an emergent light path of the laser light source module and is used for carrying out phase modulation on the incident illumination light beams, the control module is electrically connected with the active electric tuning super-surface device and is used for applying time sequence control electric signals to the device, driving the active electric tuning super-surface device to carry out dynamic phase modulation on the illumination light beams with different wavelengths in time sequence, enabling emergent light beams to generate deflection of a preset angle theta, and the imaging module is used for receiving the deflected light beams and forming images, wherein the control module is used for enabling the light beams with different deflection states to be uniformly overlapped on a projection surface through controlling the active electric tuning super-surface device, so that laser speckle is suppressed.

Inventors

  • CHEN PENG
  • DAI MING
  • WANG LIN
  • SUI LEI

Assignees

  • 歌尔光学科技有限公司

Dates

Publication Date
20260508
Application Date
20250930

Claims (11)

  1. 1. A laser projection system, comprising: A laser light source module (1) for providing an illumination beam; The active electric tuning super-surface device (2) is arranged on the light emergent path of the laser light source module (1) and is used for carrying out phase modulation on an incident illumination beam; The control module (3) is electrically connected with the active electric tuning super-surface device (2) and is used for applying time sequence control electric signals to the active electric tuning super-surface device (2) to drive the active electric tuning super-surface device to dynamically modulate the phases of illumination light beams with different wavelengths in a time sharing way so as to enable the emergent light beams to deflect at a target angle; An imaging module (4) for receiving the deflected light beam and forming an image; the control module (3) controls the active electric tuning super-surface device (2) to enable light beams with different deflection states to be uniformly overlapped on a projection surface, so that laser speckles are restrained.
  2. 2. The laser projection system according to claim 1, wherein the active electrically tuned super surface device (2) comprises, in a stacked arrangement: a first transparent substrate (21); A first transparent electrode layer (22) formed on the first transparent substrate (21); a super surface structure layer (23) which is arranged on the first transparent electrode layer (22) and comprises nano structure units which are periodically arranged; a layer of liquid crystal material (24) overlying the super surface structure layer (23); a second transparent electrode layer (25) formed on the liquid crystal material layer (24); a second transparent substrate (26) covering the second transparent electrode layer (25); the first transparent electrode layer (22) and the second transparent electrode layer (25) are used for receiving the electric signals provided by the control module (3) so as to form an electric field in the liquid crystal material layer (24), and the dynamic modulation of the phase of the light beam is realized by changing the orientation of liquid crystal molecules in the liquid crystal material layer (24).
  3. 3. The laser projection system according to claim 2, wherein the liquid crystal material layer (24) is a dual-frequency modulation liquid crystal material formed by two different refractive indexes, and the refractive index difference Δn of the two different refractive index materials is 0.2-0.3; The control module (3) is configured to control the orientation of liquid crystal molecules in the layer of liquid crystal material (24) by switching the frequency of the drive signal, wherein: in a low frequency driving mode, the liquid crystal molecules are aligned parallel to the electric field direction; in the high frequency driving mode, the liquid crystal molecules are aligned perpendicular to the electric field direction.
  4. 4. The laser projection system according to claim 2, wherein the first transparent electrode layer (22) and the second transparent electrode layer (25) each have a thickness of 20 nm-100 nm and are each patterned into a pixelated electrode array; each electrode unit in the pixelated electrode array can be independently addressed and is used for providing driving voltage for one or more corresponding nanostructure units, and local independent regulation and control of the phase of an incident illumination beam are realized by applying different driving voltages to each electrode unit.
  5. 5. The laser projection system according to claim 2, characterized in that the cross section of the nanoscale structural elements of the super-surface structural layer (23) is rectangular and satisfies an aspect ratio L/W >1:1, where L is the length of the nanoscale structural elements and W is the width of the nanoscale structural elements.
  6. 6. The laser projection system of claim 5, wherein the aspect ratio L/W of the nanoscale structural elements is 1:1.8.
  7. 7. The laser projection system according to any of claims 1-6, characterized in that the overall thickness of the active electrically tuned super surface device (2) is less than 1 μm.
  8. 8. The laser projection system according to claim 1, wherein the control module (3) comprises: A calculation unit (31) for calculating a phase distribution of the surface of the active electrically tunable super-surface device (2) from target deflection angles θ and Φ by a phase modulation function of Φ (x, y) = (2pi/λ) (x·sinθ·cos Φ+y·sinθ·sinΦ), where λ is a wavelength of an incident illumination beam and (x, y) is a coordinate position on the surface of the active electrically tunable super-surface device (2); And the driving signal generating unit (32) is used for converting the calculated phase distribution phi (x, y) into corresponding voltage control signals so as to drive each nanostructure unit of the super-surface structure layer (23) to realize the required spatial phase modulation.
  9. 9. The laser projection system according to claim 1, wherein the imaging module (4) comprises a display unit (41) and an optical lens group (42), wherein: -the display unit (41) is configured to receive and process an outgoing light beam modulated by the active electrically tuned super surface device (2); The optical lens group (42) is used for focusing and imaging the light beam output by the display unit (41) so as to form a clear and speckle-free projection image on a projection surface.
  10. 10. A laser speckle suppression method, comprising: providing an illumination beam by means of a laser light source module (1) and directing it to an active electrically tuned super surface device (2); Applying a time sequence controlled electric signal to the active electric tuning super-surface device (2) through the control module (3), and driving the active electric tuning super-surface device (2) to perform time-interval dynamic phase modulation on an incident illumination beam, so that an emergent beam deflects by a preset angle; receiving the deflected emergent beam through an imaging module (4) and imaging; The active electric tuning super-surface device (2) is controlled by the control module (3), so that light beams in different deflection states are uniformly overlapped in a preset angle range, and laser speckles are restrained.
  11. 11. An optical display device comprising the laser projection system of any of claims 1-10.

Description

Laser projection system, laser speckle suppression method and optical display device Technical Field The embodiment of the application relates to the technical field of optical display, in particular to a laser projection system, a laser speckle suppression method and optical display equipment. Background Laser projection has been widely used in many projection scenes because of its remarkable advantages such as high color gamut and long lifetime. However, the high coherence of laser light becomes a key factor for restricting its display effect. When the laser light source is used for projection imaging, the image displayed on the screen has strong granular sense under the observation of human eyes, namely, the laser speckle phenomenon appears, the quality of the displayed image is greatly reduced, and the watching experience is seriously influenced. Currently, there are some solutions to the laser speckle problem. For example, mechanical dithering, alleviates speckle by dithering the projection curtain or vibrating diffuser, but this approach introduces motion devices, resulting in noise and wear on the system, which reduces product reliability and lifetime. The rotating diffusion sheet method breaks the coherence by dynamically changing the optical path difference, but requires a high rotation motor (typically 6000 rpm), consumes more than 3W and generates electromagnetic interference. Static subsurface methods use fixed nanostructures to produce random phase distributions, but still require the use of moving parts, such as electronically controlled micro-nano rotary stages. In the prior art, the contradiction of 'insufficient dynamic regulation and control precision' (mechanical shake angle error +/-0.5 DEG) and 'poor adaptability to a static scheme' exists, and particularly in a miniaturized projection module, real-time speckle suppression with high frequency (> 1 kHz) and low power consumption (< 0.5W) is difficult to realize, which becomes a bottleneck for restricting the further development of the laser projection technology. Disclosure of Invention The application aims to provide a novel technical scheme of a laser projection system, a laser speckle suppression method and optical display equipment, and aims to solve the problem of laser speckle in the existing laser projection technology. In a first aspect, an embodiment of the present application provides a laser projection system, including: The laser light source module is used for providing illumination light beams; The active electric tuning super-surface device is arranged on the light emitting path of the laser light source module and is used for carrying out phase modulation on an incident illumination beam; the control module is electrically connected with the active electric tuning super-surface device and is used for applying time sequence control electric signals to the active electric tuning super-surface device to drive the active electric tuning super-surface device to dynamically modulate the phases of illumination light beams with different wavelengths in a time-sharing manner so as to enable the emergent light beams to deflect at a target angle; an imaging module for receiving the deflected light beam and forming an image; the control module controls the active electric tuning super-surface device to enable light beams with different deflection states to be uniformly overlapped on the projection surface, so that laser speckles are restrained. Optionally, the active electrically tunable super-surface device includes: A first transparent substrate; a first transparent electrode layer formed on the first transparent substrate; The super-surface structure layer is arranged on the first transparent electrode layer and comprises nano-structure units which are periodically arranged; a liquid crystal material layer covering the super-surface structure layer; a second transparent electrode layer formed on the liquid crystal material layer; A second transparent substrate covering the second transparent electrode layer; The first transparent electrode layer and the second transparent electrode layer are used for receiving the electric signals provided by the control module so as to form an electric field in the liquid crystal material layer, and the dynamic modulation of the phase of the light beam is realized by changing the orientation of liquid crystal molecules in the liquid crystal material layer. Optionally, the liquid crystal material layer is a dual-frequency regulation liquid crystal material formed by two different refractive indexes, and the refractive index difference delta n of the two different refractive index materials is 0.2-0.3; The control module is configured to control an orientation of liquid crystal molecules in the layer of liquid crystal material by switching a frequency of a drive signal, wherein: in a low frequency driving mode, the liquid crystal molecules are aligned parallel to the electric field direction; in th