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CN-122018150-A - Broadband optical system for achromatizing

CN122018150ACN 122018150 ACN122018150 ACN 122018150ACN-122018150-A

Abstract

The invention provides a achromatic wide-band optical system, which comprises a Micro-LED light source, an optical lens, a coupling-in holographic grating, a holographic optical waveguide, a coupling-out holographic grating and an RGB color conversion module, wherein light beams emitted by the Micro-LED light source are collimated by the optical lens and then are parallel to the coupling-in holographic grating, the coupling-in holographic grating couples the light beams into the holographic optical waveguide, the light beams reach the coupling-out holographic grating after propagating in the holographic optical waveguide, the coupling-out holographic grating diffracts the light beams out of the holographic optical waveguide and enter the RGB color conversion module, and the RGB color conversion module performs color conversion on the light beams. The invention effectively suppresses light path dispersion in a wide band range and solves the problem of color deviation of an external real scene image caused by quantum dot absorption.

Inventors

  • LU JIANGANG
  • Wu Aojie
  • DING WEIPING
  • TANG MINGYUAN
  • LIU YUBO

Assignees

  • 上海交通大学

Dates

Publication Date
20260512
Application Date
20260331

Claims (10)

  1. 1. The wide-band optical system is characterized by comprising a Micro-LED light source, an optical lens, a coupling-in holographic grating, a holographic optical waveguide, a coupling-out holographic grating and an RGB color conversion module, wherein light beams emitted by the Micro-LED light source are collimated by the optical lens and then are parallel to the coupling-in holographic grating, the coupling-in holographic grating couples the light beams into the holographic optical waveguide, the light beams reach the coupling-out holographic grating after propagating in the holographic optical waveguide, the coupling-out holographic grating diffracts the light beams out of the holographic optical waveguide and enter the RGB color conversion module, and the RGB color conversion module performs color conversion on the light beams.
  2. 2. The dispersion reducing broadband optical system of claim 1 wherein the Micro-LED light source is a blue light Micro-LED.
  3. 3. The dispersion removing broadband optical system of claim 1 wherein the light beam is totally reflected within the holographic optical waveguide.
  4. 4. The dispersion removing broadband optical system of claim 1 wherein the light beam undergoes multiple orders of diffraction within the outcoupling holographic grating.
  5. 5. The dispersion reducing broadband optical system of claim 4 wherein the light beam is directionally diffracted out of the waveguide or reflectively propagated in the waveguide when subjected to multi-order diffraction.
  6. 6. The dispersion removing broadband optical system of claim 1 wherein the RGB color conversion module includes a red quantum dot pixel block, a green quantum dot pixel block, a transparent pixel block.
  7. 7. The dispersion reducing broadband optical system of claim 6 wherein the red quantum dot pixel blocks, green quantum dot pixel blocks, transparent pixel blocks are arranged in a1 x 3 linear array.
  8. 8. The dispersion removing broadband optical system of claim 6 further comprising an RGB filter module disposed on the other side of the out-coupling holographic grating relative to the holographic optical waveguide, the RGB filter module configured to input ambient light.
  9. 9. The dispersion reducing broadband optical system according to claim 8, wherein the RGB filter module includes a red filter pixel block, a green filter pixel block, and a blue filter pixel block, the red filter pixel block being disposed in one-to-one correspondence with the red quantum dot pixel block, the green filter pixel block being disposed in one-to-one correspondence with the green quantum dot pixel block, and the blue filter pixel block being disposed in one-to-one correspondence with the transparent pixel block.
  10. 10. The dispersion removing broadband optical system of claim 8 wherein the RGB filter module covers the out-coupling holographic grating, the RGB filter module being larger in size than the RGB color conversion module.

Description

Broadband optical system for achromatizing Technical Field The invention relates to the technical field of virtual reality, in particular to a wide-band optical system for achromatizing. Background As technology continues to advance, mobile devices are evolving from portable to wearable and immersive. Augmented Reality (AR) is a space computing and displaying technology integrating virtual information and a real environment, and AR glasses based on the same are expected to become next-generation mainstream mobile intelligent terminals following a smart phone. The AR glasses generate virtual images by using the micro display screen, and the virtual images are seamlessly overlapped with the real scene by the precise optical system, so that visual experience of virtual-real fusion is realized, and a user can clearly observe the external environment and can naturally perceive the effect of digital information overlapped on the virtual images. Because the virtual image needs to be optically superimposed with the real scene in a space consistent with the retina, the imaging system of the AR glasses generally does not place the display unit directly in front of the user's line of sight, but aligns and synthesizes the virtual light path from the display source and the real light path penetrating the lens in space through an optical relay and light combining structure (such as a beam splitter, a diffraction grating or a holographic waveguide, etc.), and finally forms a unified fusion image on the retina of the human eye. The optical system of the AR glasses mainly comprises a micro display screen, a relay optical system and an optical combiner, and the working flow of the AR glasses is that firstly, a high-resolution dynamic virtual image is generated by the micro display screen, light rays emitted by the image immediately enter the relay optical system and are calibrated by optical elements such as a micro lens array and a free-form surface prism in the relay optical system to form a collimation light field with uniform brightness, then the light field is guided to the optical combiner (such as a semi-transparent semi-reflective film, a volume hologram element HOE or a grating waveguide and the like) to accurately superimpose the virtual image in a real visual field while keeping high ambient light transmittance, and finally, a composite light field fused with virtual and real information enters a human eye to form a fused image on a retina, so that the effect of augmented reality is achieved. The AR glasses can be divided into single-color and full-color according to display colors, wherein the single-color AR glasses are simple in structure, easier to realize in light path design and lower in cost, are suitable for scenes with low color requirements such as industrial prompt and navigation annotation, and the full-color AR glasses can display natural and rich color information, can remarkably improve image reality and human-computer interaction experience, are more suitable for consumer-level application requirements and meet the requirements of future mobile terminals, so that the AR glasses become the main stream direction of current technical development. At present, the main technical scheme for realizing full-color display by AR glasses mainly comprises two main technical schemes, namely a full-color Micro-OLED Micro-display chip is used as a Micro-display screen to directly output full-color images, and the other main technical scheme comprises a Micro-LED Micro-display screen based on three independent types of red, green and blue, wherein three primary colors of light are spatially and spectrally synthesized through a beam splitting and combining optical system to finally generate full-color images. Both of these schemes can provide full-color display effects with high resolution, high contrast, and high response speed, but still face many drawbacks. Firstly, whether a single-chip full-color Micro-OLED or a three-color Micro-LED beam splitting and combining structure is adopted, an optical system is required to integrate a plurality of groups of optical elements, so that the optical path is lengthy and complex, the optical machine is huge and the quality is overweight, the wearing burden of the whole machine is aggravated, secondly, chromatic light can generate chromatic dispersion in a waveguide or lens medium due to the refractive index difference of different wavelengths, color separation, edge blurring, rainbow effect and the like are caused, the image fidelity and the user experience are affected, finally, the Micro-OLED is limited by the yield and the service life of an evaporation process, and the Micro-LED depends on high-precision mass transfer and bonding technology, so that the manufacturing difficulty and the cost are high, and the large-scale application of the Micro-LED in consumer AR glasses is seriously restricted. Therefore, on the premise of ensuring the display performance, the quality