Dechromatic broadband optical system

Abstract

The invention provides an achromatic broadband 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, and is characterized in that light beams emitted by the Micro-LED light source are collimated by the optical lens and then enter the coupling-in holographic grating in parallel; the coupling-in holographic grating couples the light beam into the holographic optical waveguide, the light beam is transmitted in the holographic optical waveguide and then reaches the coupling-out holographic grating, and the coupling-out holographic grating diffracts the light beam out of the holographic optical waveguide and enters the RGB color conversion module. The RGB color conversion module performs color conversion on the light beam. According to the invention, optical path dispersion is effectively inhibited in a broadband range, and the problem of color deviation of an external real scene image caused by quantum dot absorption is solved.

Description

Technical Field

[0001] This invention relates to the field of virtual reality technology, and in particular to a wideband optical system that eliminates dispersion. Background Technology

[0002] With continuous technological advancements, mobile devices are evolving from portable to wearable and immersive applications. Augmented Reality (AR), as a spatial computing and display technology that integrates virtual information with the real environment, is expected to make AR glasses the next mainstream mobile smart terminal after smartphones. AR glasses use microdisplays to generate virtual images and seamlessly overlay them onto real scenes through a precision optical system, achieving a "virtual-real fusion" visual experience. Users can clearly observe the external environment and naturally perceive the effects of the digital information superimposed on it. Because virtual images need to be optically superimposed on the retina in a spatially consistent manner with the real scene, the imaging system of AR glasses typically does not place the display unit directly in front of the user's line of sight. Instead, it uses optical relays and light combining structures (such as beam splitters, diffraction gratings, or holographic waveguides) to spatially align and synthesize the virtual light path from the display source with the real light path penetrating the lens, ultimately forming a unified fused image on the human retina.

[0003] The optical system of AR glasses mainly consists of three parts: a micro-display, a relay optical system, and an optical combiner. Its workflow is as follows: First, the micro-display generates a high-resolution dynamic virtual image. The light emitted from this image then enters the relay optical system, where it is calibrated by optical elements such as microlens arrays and freeform prisms to form a collimated light field with uniform brightness. Subsequently, this light field is guided to the optical combiner (such as a semi-transparent and semi-reflective film, a volume holographic element (HOE), or a grating waveguide) to accurately superimpose the virtual image onto the real field of vision while maintaining high ambient light transmittance. Finally, the composite light field, which integrates virtual and real information, enters the human eye, forming a fused image on the retina, thus achieving the effect of augmented reality.

[0004] AR glasses can be categorized into monochrome and full-color based on their display colors. Monochrome AR glasses have a simpler structure, easier optical path design, and lower cost, making them suitable for scenarios with low color requirements, such as industrial prompts and navigation labels. Full-color AR glasses, on the other hand, can present natural and rich color information, significantly improving image realism and human-computer interaction, better meeting the needs of consumer applications and future mobile terminals, thus becoming the mainstream direction of current technological development. Currently, there are two main technical solutions for achieving full-color display in AR glasses: one uses a full-color Micro-OLED microdisplay chip as a miniature display screen to directly output full-color images; the other is based on three independent Micro-LED microdisplays (red, green, and blue), using a beam-splitting and combining optical system to spatially and spectrally synthesize the three primary colors to ultimately generate a full-color image. Both solutions can provide high resolution, high contrast, and high response speed full-color display effects, but still face many shortcomings. First, regardless of whether a single-chip full-color Micro-OLED or a three-color Micro-LED beam-splitting architecture is used, the optical engine system needs to integrate multiple sets of optical components, resulting in a long and complex optical path. This leads to a large and heavy optical engine, increasing the overall wearing burden. Second, full-color light will cause dispersion in the waveguide or lens medium due to the difference in refractive index of different wavelengths, causing color separation, edge blurring, rainbow effects, etc., affecting image fidelity and user experience. Finally, Micro-OLED is limited by the yield and lifespan of the evaporation process, while Micro-LED relies on high-precision mass transfer and bonding technology. Both are difficult and expensive to manufacture, which seriously restricts their large-scale application in consumer AR glasses. Therefore, how to significantly reduce the weight of the optical engine and the overall device while ensuring display performance, and effectively reduce manufacturing costs, has become a key path that urgently needs to be broken through to promote AR glasses to the consumer market.

[0005] Therefore, those skilled in the art are dedicated to providing a wide-band optical system that can effectively suppress optical path dispersion over a wide band, while reducing equipment weight and manufacturing costs. Summary of the Invention

[0006] In view of the deficiencies in the prior art, the technical problem to be solved by the present invention is how to provide an optical system that can effectively suppress optical path dispersion over a wide wavelength range.

[0007] To achieve the above objectives, the present invention provides a wideband optical system for dispersion reduction, comprising a Micro-LED light source, an optical lens, an input holographic grating, a holographic waveguide, an output holographic grating, and an RGB color conversion module. A light beam emitted from the Micro-LED light source is collimated by the optical lens and then incident parallel to the input holographic grating. The input holographic grating couples the light beam into the holographic waveguide. After propagating within the holographic waveguide, the light beam reaches the output holographic grating, which diffracts the light beam out of the holographic waveguide and into the RGB color conversion module. The RGB color conversion module performs color conversion on the light beam.

[0008] Preferably, the Micro-LED light source is a blue Micro-LED.

[0009] Furthermore, the light beam undergoes total internal reflection inside the holographic waveguide.

[0010] Furthermore, the light beam undergoes multi-level diffraction within the coupled holographic grating.

[0011] Preferably, when the light beam undergoes multi-level diffraction, it is either directionally diffracted out of the waveguide or reflected and propagated within the waveguide.

[0012] Preferably, the RGB color conversion module includes red quantum dot pixel blocks, green quantum dot pixel blocks, and transparent pixel blocks.

[0013] Furthermore, the red quantum dot pixel blocks, green quantum dot pixel blocks, and transparent pixel blocks are arranged in a 1×3 linear array.

[0014] Furthermore, it also includes an RGB filter module, which is disposed on the other side of the coupled holographic grating relative to the holographic waveguide, and the RGB filter module is used to input external light.

[0015] Furthermore, the RGB filter module includes a red light filter pixel block, a green light filter pixel block, and a blue light filter pixel block, wherein the red light filter pixel block is configured in a one-to-one correspondence with the red quantum dot pixel block, the green light filter pixel block is configured in a one-to-one correspondence with the green quantum dot pixel block, and the blue light filter pixel block is configured in a one-to-one correspondence with the transparent pixel block.

[0016] Preferably, the RGB filter module covers the coupled holographic grating, and the size of the RGB filter module is larger than that of the RGB color conversion module.

[0017] The present invention has at least the following beneficial technical effects: The dispersion-eliminating wideband optical system provided by this invention adopts a front-end display architecture and uses an optical waveguide to achieve high-fidelity, low-dispersion transmission and precise pixel coupling of blue Micro-LEDs, directly exciting pixelated red, green, and blue quantum dot arrays to generate color images. By depositing red, green, and blue narrowband filter coatings on the outer side of the holographic optical waveguide in areas corresponding to the quantum dot pixels, the incident ambient light retains only spectral components compatible with the emission band of its quantum dots at each pixel position and efficiently penetrates the quantum layer. Thus, without introducing additional optical losses, it simultaneously ensures display brightness and real-world color fidelity, solving the problem of real-world color distortion caused by the selective absorption of blue light when ambient light passes through the quantum dot layer.

[0018] This invention designs optical waveguide transmission and deflection paths only for blue light and other wavelength bands, reducing the complexity of optical path design, simplifying the manufacturing difficulty of optical waveguides and improving mass production yield; since it is single-wavelength transmission, it eliminates the influence of dispersion during transmission.

[0019] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the dispersion-eliminating broadband optical system structure according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the RGB color conversion module according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the RGB filter module according to an embodiment of the present invention.

[0021] In the diagram, 101 is a Micro-LED light source, 102 is an optical lens, 103 is a coupled holographic grating, 104 is a holographic waveguide, 105 is an RGB filter module, 106 is an coupled holographic grating, 107 is an RGB color conversion module, 201 is a red quantum dot pixel block, 202 is a green quantum dot pixel block, 203 is a transparent pixel block, 301 is a red light filter pixel block, 302 is a green light filter pixel block, and 303 is a blue light filter pixel block. Detailed Implementation

[0022] The preferred embodiments of the present invention are described below to make the technical content clearer and easier to understand. The present invention can be embodied in many different forms, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0023] In the accompanying drawings, components with the same structure are represented by the same numerical symbols, and components with similar structures or functions are represented by similar numerical designations. The dimensions and thicknesses of each component shown in the drawings are arbitrary, and the present invention does not limit the dimensions and thicknesses of each component. To make the illustrations clearer, the thickness of some components has been appropriately exaggerated in the drawings.

[0024] This invention provides a wideband optical system for eliminating dispersion. It uses a monochromatic Micro-LED as a single light source to illuminate a patterned quantum dot layer. The corresponding pixels undergo color conversion, forming a full-color image with the transmitted light. This achieves high-fidelity, low-dispersion transmission and precise pixel coupling, and solves the problem of color deviation in real-world scene images due to the absorption of color by the patterned quantum dot layer.

[0025] like Figure 1 As shown, the wideband optical system for dissipation cancellation in this embodiment includes a Micro-LED light source 101, an optical lens 102, a coupled holographic grating 103, a holographic waveguide 104, a coupled-out holographic grating 106, and an RGB color conversion module 107. The Micro-LED light source 101 serves as a miniature display screen and is placed on one side of the optical lens 102. The light beam emitted by the Micro-LED light source 101 is collimated by the optical lens 102 and then incident on the coupled holographic grating 103 in the form of parallel light. The coupled holographic grating 103 efficiently couples the light beam into the holographic waveguide 104 through diffraction. The light beam propagates laterally in the holographic waveguide 104 by total internal reflection until it reaches the coupled-out holographic grating 106. When the light beam reaches the coupling holographic grating 106, multi-level diffraction occurs. Part of the light is directionally diffracted out of the holographic waveguide 104, while the other part continues to propagate through reflection within the holographic waveguide 104. This achieves spatial multiplexing and expansion of the light field in the eye-movement direction, significantly increasing the effective eye-movement range. The emitted light beam then enters the RGB color conversion module 107 to perform color conversion.

[0026] In this embodiment, the Micro-LED light source 101 is a blue light source, therefore, the pattern emitted by the Micro-LED light source 101 is a blue light pattern.

[0027] like Figure 2As shown, the RGB color conversion module 107 consists of periodically arranged red quantum dot pixel blocks 201, green quantum dot pixel blocks 202, and transparent pixel blocks 203. When blue light shines on the red quantum dot pixel block 201, it is absorbed and converted into red light; when blue light shines on the green quantum dot pixel block 202, it is absorbed and converted into green light; and when blue light shines on the transparent pixel block 203, it is directly transmitted without conversion, retaining the original blue light component. The three types of pixel blocks in the RGB color conversion module 107 are the same size and are arranged in a 1×3 linear array in space. The three primary colors of light are spatially registered and superimposed at the micrometer level to form a high-resolution full-color image, which is directly projected into the human eye along the light path and ultimately perceived by the human eye, generating a natural, bright, and color-balanced augmented reality image.

[0028] In another embodiment of the present invention, to achieve optical fusion and color coordination between real ambient light and virtual images, an RGB filter module 105 is integrated on the outside of the coupled holographic grating 106 in the optical system. For example... Figure 3As shown, the RGB filter module 105 consists of red light filter pixels 301, green light filter pixels 302, and blue light filter pixels 303, which are uniformly distributed in a periodic array on the entire surface of the coupled holographic grating 106. The overall size of the RGB filter module 105 is slightly larger than that of the RGB color conversion module 107 to ensure complete coverage of the latter, so that all ambient light entering the RGB color conversion module 107 must pass through the RGB filter module 105 before reaching the human eye. The geometric dimensions, spatial period, and arrangement order of the red light filter pixels 301, green light filter pixels 302, and blue light filter pixels 303 are strictly consistent with the red quantum dot pixels 201, green quantum dot pixels 202, and transparent pixels 203 of the RGB color conversion module 107, and pixel-level alignment is achieved in the direction perpendicular to the optical axis. In this configuration, vertically incident ambient light first passes through the RGB filter module 105. The red component of the ambient light passes through the red filter pixel block 301, is transmitted through the holographic waveguide 104, and is projected onto the vicinity of the red quantum dot pixel block 201 and directly transmitted. Similarly, the green component passes through the green filter pixel block 302, is transmitted through the holographic waveguide 104, and is projected onto the green quantum dot pixel block 202 and transmitted. The blue component passes through the blue filter pixel block 303, is transmitted through the holographic waveguide 104, and is precisely aligned with the transparent pixel block 203. Since there is no quantum dot material in this area, the blue light is transmitted almost without loss. Thus, the quantum dot material selectively absorbs and converts only the blue light actively emitted by the Micro-LED light source 101, while having almost no absorption interference from the ambient natural blue light, effectively avoiding the attenuation of ambient blue light caused by non-target absorption. At the same time, the red and green light components from the outside world can also pass through their respective channels with high fidelity and high efficiency, thereby ensuring the accurate matching and natural integration of virtual images and real backgrounds in the three dimensions of brightness, chromaticity and spatial distribution, and significantly improving the color balance of the display system.

[0029] The dispersion-eliminating broadband optical system of the present invention uses blue Micro-LED as a single light source. Through the coordinated modulation of the RGB color conversion module and the RGB filter module, it solves the problems of color distortion of the displayed scene pattern and color shift of the real scene in the front-end light emission. It has the advantages of compact structure, light weight, excellent performance, low cost and low power consumption.

[0030] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A dispersion-agnostic broadband optical system, characterized in that, The system includes a Micro-LED light source, an optical lens, an inserted holographic grating, a holographic waveguide, an exited holographic grating, and an RGB color conversion module. The light beam emitted by the Micro-LED light source is collimated by the optical lens and then incident parallel to the inserted holographic grating. The inserted holographic grating couples the light beam into the holographic waveguide. After propagating within the holographic waveguide, the light beam reaches the exited holographic grating, which diffracts the light beam out of the holographic waveguide and into the RGB color conversion module. The RGB color conversion module performs color conversion on the light beam.

2. The dispersion-averse broadband optical system as described in claim 1, characterized in that, The Micro-LED light source is a blue Micro-LED.

3. The dispersion-averse broadband optical system as described in claim 1, characterized in that, The light beam undergoes total internal reflection inside the holographic waveguide.

4. The dispersion-averse broadband optical system as described in claim 1, characterized in that, The light beam undergoes multi-level diffraction within the coupled holographic grating.

5. The dispersion-averse broadband optical system as described in claim 4, characterized in that, When the beam undergoes multi-level diffraction, it is either directionally diffracted out of the waveguide or reflected and propagated within the waveguide.

6. The dispersion-averse broadband optical system as described in claim 1, characterized in that, The RGB color conversion module includes red quantum dot pixel blocks, green quantum dot pixel blocks, and transparent pixel blocks.

7. The dispersion-averse broadband optical system as described in claim 6, characterized in that, The red quantum dot pixel blocks, green quantum dot pixel blocks, and transparent pixel blocks are arranged in a 1×3 linear array.

8. The dispersion-averse broadband optical system as described in claim 6, characterized in that, It also includes an RGB filter module, which is disposed on the other side of the coupled holographic grating relative to the holographic waveguide. The RGB filter module is used to input external light.

9. The dispersion-averse broadband optical system as described in claim 8, characterized in that, The RGB filter module includes a red light filter pixel block, a green light filter pixel block, and a blue light filter pixel block. The red light filter pixel block is configured in a one-to-one correspondence with the red quantum dot pixel block, the green light filter pixel block is configured in a one-to-one correspondence with the green quantum dot pixel block, and the blue light filter pixel block is configured in a one-to-one correspondence with the transparent pixel block.

10. The dispersion-averse broadband optical system as described in claim 8, characterized in that, The RGB filter module covers the coupled holographic grating, and the size of the RGB filter module is larger than that of the RGB color conversion module.

Images