High-definition retroreflection suspension imaging device based on Fresnel lens

Abstract

The utility model discloses a high-definition retroreflection suspension imaging device based on a Fresnel lens. The high-definition retroreflection suspension imaging device comprises a light source display unit, an imaging unit and a control unit which are sequentially arranged along a light path, a beam splitter; a Fresnel lens; a retroreflector; imaging the area in the air. According to the utility model, through the synergistic effect of the technical characteristics, a complete closed loop of light source generation, light path guiding, focusing amplification, retroreflection correction and aerial imaging is formed, and compared with the prior art, the overall advantages are realized as follows: the resolution is obviously improved; aberration self-elimination; stray light suppression; and the cost and the applicability are optimized.

Description

Technical Field

[0001] This utility model relates to the field of levitation imaging technology, and in particular to a high-definition retroreflective levitation imaging device based on a Fresnel lens. Background Technology

[0002] Aerial imaging display technology, as an emerging display technology that can form realistic images in the air without the need for a physical carrier, has shown broad application prospects in fields such as in-vehicle HUDs (Head-Up Displays), medical display terminals, interactive advertising devices, and virtual control consoles, thanks to its advantages such as non-contact interaction and intuitive visual presentation. This technology uses optical elements to control light, allowing images to levitate directly in the air, effectively solving problems such as contact contamination risks, visual fatigue, and space occupation associated with traditional physical screens in certain scenarios, making it a research hotspot in the field of optical displays.

[0003] In existing technologies, aerial imaging systems based on retroreflection (AIRR) are one of the mainstream solutions for achieving aerial imaging. Its core principle is to use a microstructured reflective array (such as a microprism array) to retroreflect incident light rays, causing the light to converge in the air to form a real image. A typical AIRR system usually includes a light source display unit, a retroreflector, and a light path guiding structure. The image light generated by the light source display unit is guided to the retroreflector via the light path, and the retroreflector reflects the light along its original path to form a suspended image in the air.

[0004] However, existing AIRR systems have the following significant drawbacks that limit their further application in the field of high-definition displays:

[0005] Low imaging resolution: Due to the limitations of the processing precision and unit size of the microstructure reflective array, light is prone to diffraction and diffusion during reflection, resulting in the loss of image details. The modulation transfer function (MTF) is usually below 20%, which is difficult to meet the requirements of high-definition display.

[0006] Significant aberrations: The optical path design of the microstructured reflective array lacks an aberration correction mechanism. During multiple reflections and propagation of light, spherical aberration and chromatic aberration are easily generated, resulting in blurred image edges and obvious distortion.

[0007] Severe stray light interference: Most existing systems do not have effective light-shielding or anti-reflection structures. External stray light and secondary reflections from internal light sources (such as reflections from the light source display unit itself) can easily get mixed into the imaging light path, resulting in decreased image contrast and increased background noise.

[0008] Large-size applications are limited: In order to improve the imaging effect, traditional solutions have tried to introduce glass convex lenses for optical path focusing and magnification. However, glass lenses have problems such as high density, heavy weight, fragility, high processing difficulty and high cost, making it difficult to achieve lightweight and low-cost mass production of large-size imaging systems larger than 5 inches.

[0009] In summary, existing aerial imaging technologies have significant shortcomings in terms of resolution, aberration control, stray light suppression, and cost of large-scale applications, and improvements are urgently needed to address these issues. Summary of the Invention

[0010] This invention addresses the shortcomings of existing technologies, such as low imaging resolution, significant aberrations, severe stray light interference, and limitations in large-size applications, by providing a new high-definition retroreflective levitation imaging device based on Fresnel lenses.

[0011] To solve the above-mentioned technical problems, this utility model is achieved through the following technical solution:

[0012] A high-definition retroreflective levitation imaging device based on a Fresnel lens includes the following components arranged sequentially along the optical path:

[0013] A light source display unit is used to generate image beams;

[0014] A beam splitter is tilted and positioned in the optical path of the light source display unit to change the optical path direction of the image beam.

[0015] A Fresnel lens, placed in the optical path of a beam splitter, is used to focus and magnify the image beam;

[0016] An antireflector, placed in the optical path of a Fresnel lens, is used to reflect the image beam along the original optical path;

[0017] The aerial imaging area, located symmetrically to the light source display unit relative to the beam splitter, is used to receive the image beam and form a suspended image.

[0018] The core function of the light source display unit is to generate an image beam, providing a high-resolution raw image signal and laying the foundation for high-definition imaging in subsequent optical systems. Compared to the image detail loss problem caused by low PPI light sources in existing technologies, high PPI light sources can effectively reduce information loss during the imaging process, directly improving the clarity of the final suspended image and meeting the requirements of high-definition display.

[0019] The core function of the beam splitter is to precisely change the direction of the optical path: on the one hand, it reflects the image beam emitted by the light source display unit to the Fresnel lens, ensuring that the light is transmitted along a preset path; on the other hand, it transmits the image beam returned by the retroreflector to the imaging area in the air, realizing "bidirectional guidance" of the optical path. This design reduces energy loss and directional deviation, improves light utilization, and makes the system structure more compact, helping to solve the problems of complex optical paths and large size in existing technologies.

[0020] Fresnel lenses, whose core function is to focus and magnify image beams, have significant advantages over traditional glass convex lenses: low material cost and ease of processing, enabling large-scale mass production and overcoming the drawbacks of high processing difficulty and cost of large-size glass lenses; their lightweight characteristics reduce the overall weight of the system, making them suitable for weight-sensitive scenarios such as automotive HUDs; and their focusing and magnification functions enhance the convergence of image beams and reduce diffraction diffusion. Combined with the optical path design of subsequent retroreflectors, this effectively improves the modulation transfer function (MTF) and solves the problem of low imaging resolution in existing technologies.

[0021] The core function of a retroreflector is to reflect the received image beam along its original optical path. This "return along the original path" characteristic is key to achieving self-elimination of aberrations: after light passes through a Fresnel lens to the retroreflector, it is reflected back to the Fresnel lens along its original path, forming a symmetrical optical path, which can cancel out aberrations such as spherical aberration and chromatic aberration that may be generated by the Fresnel lens itself. Compared to the aberration accumulation problem caused by the reflection direction deviation of the microstructure reflective array in existing technologies, this design achieves active aberration elimination in principle, significantly improving imaging accuracy.

[0022] The aerial imaging area is located symmetrically to the light source display unit relative to the beam splitter, and is the area where the image beams finally converge to form a suspended image.

[0023] The various technical features of this invention work synergistically to form a complete closed loop of "light source generation - optical path guidance - focusing and magnification - retroreflection correction - aerial imaging," achieving the following advantages compared to existing technologies (such as the traditional AIRR system):

[0024] Significantly improved resolution: High-resolution display requirements are met through high-PPI light source, Fresnel lens focusing and magnification, and retroreflector optical path correction;

[0025] Self-cancellation of aberrations: Based on the "return to the original path" characteristic of retroreflectors and the design of conjugate symmetrical optical paths, automatic cancellation of aberrations during Fresnel lens and propagation is achieved, solving the problems of blurred and distorted imaging edges in existing technologies;

[0026] Stray light suppression: The precise optical path guidance of the beam splitter and the directional reflection characteristics of the retroreflector reduce the interference of stray light from the external environment and internal secondary reflections, thereby improving the contrast and signal-to-noise ratio of the levitation image.

[0027] Cost and applicability optimization: The lightweight, low-cost materials and large-size mass production capabilities of Fresnel lenses, combined with a compact optical path design, enable the system to be used in large-size scenarios of 5 inches and above (such as virtual consoles and interactive advertising devices), overcoming the limitations of traditional glass lenses in large-size applications.

[0028] Preferably, the high-definition retroreflective levitation imaging device based on a Fresnel lens described above has a conjugate symmetric structure consisting of an aerial imaging region, a Fresnel lens, and a retroreflector, which is used to achieve aberration self-elimination of the image beam through a phase conjugate reflection optical path.

[0029] The conjugate symmetric structure formed by the aerial imaging region, Fresnel lens, and retroreflector works synergistically to create a phase-conjugate reflected light path of "light source - Fresnel lens - retroreflector - Fresnel lens - aerial imaging region" (the incident light and reflected light paths are completely coincident), achieving the following core advantages:

[0030] Self-cancellation of aberrations: The phase-conjugate reflection optical path cancels out aberrations during light propagation (such as spherical aberration, chromatic aberration, or distortion caused by Fresnel lenses), solving the problems of blurred imaging edges and loss of detail caused by aberrations in existing technologies, and significantly improving imaging clarity; Enhanced optical path stability: The conjugate symmetric structure ensures low energy loss and small directional deviation of light during round-trip propagation, making the suspended image in the aerial imaging area uniform in brightness and stable in position, avoiding the defects of image shaking and uneven brightness in traditional systems; Adaptation to high-definition requirements: Through self-cancellation of aberrations and optical path stabilization, combined with the magnification and focusing function of Fresnel lenses, the accuracy requirements of high-definition display scenarios (such as automotive HUDs and medical terminals) are met.

[0031] Preferably, in the high-definition retroreflective levitation imaging device based on a Fresnel lens described above, the Fresnel lens is made of PC, PMMA, or PET.

[0032] PC (polycarbonate) material possesses excellent mechanical strength and heat resistance, ensuring the structural stability of Fresnel lenses while adapting to complex environments such as automotive and outdoor advertising (e.g., temperature fluctuations, slight vibrations). Its mature processing technology allows for efficient mass production of large-size lenses through injection molding, solving the problems of high processing difficulty and fragility associated with traditional glass lenses. Furthermore, its lower density compared to glass significantly reduces lens weight, facilitating lightweight device design (e.g., in weight-sensitive scenarios like automotive HUDs).

[0033] PMMA (polymethyl methacrylate) material has extremely high light transmittance and excellent optical performance. It can reduce light transmission loss in lenses, ensuring the brightness and clarity of image beams, and providing an optical foundation for high-definition imaging. It is easy to cut and injection mold, with processing costs far lower than glass, and its weight is only half that of glass of the same volume. This makes it suitable for manufacturing large-size lenses, overcoming the shortcomings of traditional glass lenses that are "heavy, expensive, and difficult to process." It is particularly suitable for scenarios such as medical display terminals where both cost and light transmittance are critical.

[0034] PET (polyethylene terephthalate) material is flexible and resistant to chemical corrosion, allowing it to be made into thin Fresnel lenses. This further reduces the overall thickness and weight of the device, making it suitable for scenarios with high space requirements, such as interactive advertising equipment. Its mass production cost is low, molding efficiency is high, and its excellent anti-aging properties ensure long-term optical stability, avoiding the short lifespan and high maintenance costs associated with traditional glass lenses due to their brittleness.

[0035] Preferably, in the high-definition retroreflective levitation imaging device based on Fresnel lenses described above, the retroreflector is a reflective film with a micro prism array structure.

[0036] Miniature prism arrays utilize the geometric and optical properties of prisms to create "directional retroreflection" of incident image beams: after entering the prism, the light is precisely reflected by two reflecting surfaces and returns along its original incident path, achieving high symmetry in the optical path. Compared to traditional microstructure reflective arrays (such as spherical microlens arrays) in existing technologies, this structure exhibits smaller deviations in the reflection direction (almost no angular shift), significantly reducing diffraction and stray light generation. This provides a precise optical path basis for the formation of phase-conjugate reflective optical paths, directly improving the aberration accumulation and image blurring problems caused by reflection direction deviations in existing AIRR systems. Using film-like substrates (such as polymer films) to support the miniature prism array offers significant advantages over bulk retroreflective materials (such as glass prism arrays).

[0037] Lightweight and thin characteristics: The thin film structure has a small thickness (usually in the micrometer to millimeter range), which can significantly reduce the weight of the retroreflector, facilitates compact integration with components such as Fresnel lenses, makes the overall structure of the device simpler, and solves the problem of large system size caused by traditional bulk materials;

[0038] Low-cost mass production: The film-like substrate can be mass-produced into micro prism arrays through processes such as roll forming and injection molding. It has high production efficiency and low cost, making it suitable for large-scale applications in large-size scenarios. It overcomes the shortcomings of traditional block retroreflective materials, such as high processing difficulty and high cost.

[0039] Flexible adaptation: The membrane structure can adapt to certain curved or flat surface installation requirements, improving the assembly compatibility with the device housing and Fresnel lens, and reducing optical path offset caused by installation deviation.

[0040] Preferably, in the high-definition retroreflective levitation imaging device based on Fresnel lenses described above, the light source display unit is a liquid crystal display module or an OLED display module.

[0041] The LCD display module features high resolution, adjustable brightness, accurate color reproduction, and mature mass production technology. Its core advantages lie in: high PPI characteristics, which provide richly detailed original image beams, offering high-quality "input signals" for subsequent Fresnel lens magnification and retroreflector optical path correction, avoiding the loss of imaging details due to insufficient resolution of the light source itself, and solving the "original image blurring" problem in existing AIRR systems from the source; and mature mass production technology, which makes its cost controllable and highly stable, suitable for scenarios such as automotive HUDs that require long-term continuous operation, ensuring stable image beam output and reducing imaging flicker or distortion caused by light source fluctuations.

[0042] OLED display modules possess characteristics such as self-emissiveness, high contrast (no backlight interference), fast response speed, and wide viewing angle. Their advantages as a light source display unit are reflected in the following aspects: Self-emissiveness eliminates the need for a backlight module, resulting in more uniform light output and reducing image brightness deviations caused by uneven backlighting. Combined with directional reflection from retroreflectors, this further enhances the brightness consistency of the aerial imaging area. High contrast (darker dark areas and brighter bright areas) enhances the tonal gradations of the original image. After magnification by Fresnel lenses and retroreflection, the detail clarity of the suspended image (such as subtle data in medical display terminals) is significantly improved, solving the "hazy" image problem caused by insufficient contrast in traditional light sources. Fast response speed is suitable for dynamic image display (such as real-time traffic conditions in car navigation), avoiding motion blur and ensuring dynamic clarity in aerial imaging.

[0043] Preferably, the MTF of the suspended image formed in the aerial imaging area of ​​the high-definition retroreflective levitation imaging device based on the Fresnel lens described above is 35% to 42%.

[0044] The Modulation Transfer Function (MTF) is a key indicator of an imaging system's ability to reproduce image contrast and detail. A higher value indicates a stronger ability to transfer image edges and subtle textures. A range of 35%–42% is significantly higher than the MTF of existing traditional AIRR systems (typically <20%), meaning sharper text edges and more complete graphic details in suspended images (such as fine data in medical display terminals or navigation icons in vehicle HUDs), solving the core defects of "blurred images and loss of detail" in traditional technologies. This 35%–42% range also stably supports aerial imaging of 5-inch and larger images, ensuring no loss of image detail even after magnification by 2–4 times using Fresnel lenses. This makes it suitable for scenarios with rigid requirements for high-definition display (such as legible text and smooth dynamic images), such as vehicle HUDs and interactive advertising devices, breaking through the limitation of traditional AIRR systems that can only achieve low-precision imaging.

[0045] Preferably, in the aforementioned high-definition retroreflective levitation imaging device based on a Fresnel lens, the beam splitter is a semi-transparent reflective film used to reflect the image beam emitted by the light source display unit to the Fresnel lens; and to transmit the image beam returned by the retroreflector to the aerial imaging area.

[0046] The semi-transparent reflective film can balance the light energy of the "incident light path" and the "reflected light path", ensuring that the brightness of the final suspended image is moderate, avoiding dim imaging due to low transmittance, reducing the ineffective loss of light energy, and avoiding glare or overexposure caused by excessive light intensity in a certain path, thus providing a stable light energy basis for high-definition imaging.

[0047] Preferably, the high-definition retroreflective levitation imaging device based on a Fresnel lens described above further includes:

[0048] The housing houses the light source display unit, beam splitter, Fresnel lens, retroreflector, and aerial imaging area; the aerial imaging area is located at the window position of the housing; the inside of the housing is lined with black velvet to prevent reflections from the light source display unit and the formation of shadows.

[0049] The base is rotatably connected to the outer casing.

[0050] The outer casing secures the optical path structure: by physically constraining the relative positions of each optical component, it ensures precise alignment of all components according to the preset optical path, preventing optical path misalignment caused by external vibrations or assembly deviations, and solving the problems of image position wobbling and blurring caused by loose components in existing technologies; it also protects internal components: the casing isolates external environmental factors such as dust and moisture, preventing optical components from being contaminated or worn, and extending the device's lifespan. The base serves as the device's supporting structure, providing stable load-bearing capacity: it provides solid support for the outer casing and internal components, preventing the device from shaking due to unstable placement (such as slight vibrations in vehicle or desktop scenarios), further ensuring optical path stability. The rotation of the outer casing relative to the base allows adjustment of the orientation of the aerial imaging area (such as the pitch angle), adapting to different users' viewing angles (such as the driver's seating height in a vehicle HUD, or the doctor's operating position in a medical terminal), improving the device's human-computer interaction convenience.

[0051] The black velvet fabric prevents glare from the light source display unit, thus preventing reflections.

[0052] Absorbing stray light: The black velvet cloth has high light absorption, which can absorb excess light emitted by the light source display unit and secondary reflected light from internal components, preventing these stray lights from mixing into the imaging light path to form "reflections" or background noise, and significantly improving the contrast of the floating image (especially in dark field display).

[0053] Optimize optical path purity: Reduce stray light interference on the phase conjugate reflection optical path, ensure that the effective beam returned by the retroreflector is not contaminated, indirectly guarantee the high-definition level of the system, and solve the problems of image "ghosting" and "graying" caused by internal reflection in the existing technology.

[0054] Preferably, the high-definition retroreflective levitation imaging device based on Fresnel lenses described above has an upper shell with a window, and light-shielding plates are provided on the upper and lower sides of the window position of the upper shell to block external stray light; a retroreflector is provided on the inner side of the rear cover plate of the outer shell, and a quarter wave plate is attached to the retroreflector.

[0055] The window design on the upper shell precisely corresponds to the aerial imaging area. The window's boundaries guide the user to focus on the effective observation area of ​​the suspended image, reducing visual interference from non-imaging areas and improving the user experience. The light shield blocks stray external light. This is because ambient light (such as sunlight or indoor lighting) entering from above or below the window can easily interfere with the imaging light path, leading to increased background brightness and decreased contrast in the suspended image. The light shield physically blocks this stray light, reducing background noise and making dark areas of the image clearer (such as subtle data in medical terminals or dark icons in vehicle HUDs), solving the "grayish image" problem caused by external light interference in traditional systems. Targeted blocking of stray light above and below the window does not affect the user's normal viewing angle of the suspended image, enhancing anti-interference capabilities while maintaining ease of use.

[0056] The way the rear cover plate of the retroreflector is fixed prevents the retroreflector from shifting due to vibration or assembly errors, ensuring that light is reflected along its original path and maintaining the aberration self-elimination effect. The quarter-wave plate optimizes imaging by adjusting the polarization state of the light: it reduces polarization loss: when a retroreflector reflects light, if there are components with inconsistent polarization directions, energy loss or glare can easily occur. The quarter-wave plate can convert the polarization state of the incident light into circularly polarized light, and after retroreflection, convert it back into linearly polarized light with the same direction as the original, improving the utilization rate of effective light and enhancing the brightness of the suspended image; it suppresses reflected glare: through polarization control, stray light caused by polarization mismatch during retroreflection (such as glare caused by specular reflection) can be reduced, further improving image contrast, and working with the light-shielding plate to optimize imaging quality in complex lighting environments.

[0057] Preferably, the high-definition retroreflective levitation imaging device based on Fresnel lenses described above has a black velvet cloth on the inner side of the upper shell cover plate; an embedded screw hole structure is provided between the upper shell and the outer shell for fixation; a connecting knob structure is provided between the base and the outer shell for rotational connection; and a fixing screw hole structure is provided on the base for fixing the base.

[0058] The embedded screw hole structure achieves a tight connection between the upper shell and the outer shell through threaded engagement, providing high connection strength. This prevents relative displacement of the upper shell and outer shell due to vibration and collision, ensuring precise alignment of the upper shell window with the aerial imaging area and the positional stability of internal optical components. It also facilitates disassembly and maintenance (such as replacing optical components), balancing stability and maintainability. The connecting knob structure is an optimization of the "rotational connection between the base and the outer shell," making operation more convenient and allowing angle adjustments without tools, thus enhancing the device's flexibility in interactive scenarios (such as multi-angle displays for advertising equipment). The fixing screw hole structure provides a standardized installation interface: it can be connected to various mounting surfaces such as vehicle brackets, medical equipment operating tables, and advertising display racks via bolts, achieving "rigid fixation" of the device. Attached Figure Description

[0059] Figure 1 This is a schematic diagram of the structure of this utility model;

[0060] Figure 2 This is a cross-sectional view of the present invention;

[0061] Figure 3 This is a partial structural schematic diagram of the present invention;

[0062] Figure 4 This is a schematic diagram of the traditional retroreflective levitation imaging principle;

[0063] Figure 5 This is a schematic diagram of the Fresnel retroreflection conjugate symmetric suspension imaging principle of this utility model.

[0064] Reference numerals: 1. Light source display unit; 2. Beam splitter; 3. Fresnel lens; 4. Retroreflector; 5. Aerial imaging area; 6. Housing; 61. Black velvet cloth; 62. Base; 63. Upper shell; 64. Light shield; 65. Quarter wave plate; 66. Embedded screw hole structure; 67. Connecting knob structure; 68. Fixing screw hole structure; 100. Viewing position; 101. Traditional light source; 102. Traditional semi-transparent and semi-reflective film; 103. Traditional retroreflector; 104. Traditional suspended image. Detailed Implementation

[0065] The following is in conjunction with the appendix Figure 1-5 The present invention will be further described in detail with reference to specific embodiments, but these are not intended to limit the present invention:

[0066] A high-definition retroreflective levitation imaging device based on a Fresnel lens includes the following components arranged sequentially along the optical path:

[0067] Light source display unit 1 is used to generate image beams;

[0068] The beam splitter 2 is tilted and positioned on the optical path of the light source display unit 1 to change the optical path direction of the image beam.

[0069] Fresnel lens 3 is placed in the optical path of beam splitter 2 to focus and magnify the image beam;

[0070] Retroreflector 4 is placed in the optical path of Fresnel lens 3 to reflect the image beam along the original optical path;

[0071] The aerial imaging area 5 is located symmetrically to the light source display unit relative to the beam splitter 2, and is used to receive the image beam and form a suspended image.

[0072] Preferably, the aerial imaging region 5, Fresnel lens 3, and retroreflector 4 form a conjugate symmetric structure, which is used to achieve aberration self-elimination of the image beam through the phase conjugate reflection optical path.

[0073] Preferably, the Fresnel lens 3 is made of PC, PMMA, or PET.

[0074] Preferably, the retroreflector 4 is a reflective film with a micro prism array structure.

[0075] Preferably, the light source display unit 1 is a liquid crystal display module or an OLED display module.

[0076] Preferably, the MTF of the suspended image formed by the aerial imaging region 5 is 35% to 42%.

[0077] Preferably, the beam splitter 2 is a semi-transparent reflective film used to reflect the image beam emitted by the light source display unit 1 to the Fresnel lens 3; and to transmit the image beam returned by the retroreflector 4 to the aerial imaging area 5.

[0078] As a preferred option, it also includes:

[0079] The housing 6 is used to house the light source display unit 1, the beam splitter 2, the Fresnel lens 3, the retroreflector 4, and the aerial imaging area 5; the aerial imaging area 5 is located at the window position of the housing 6; the inside of the housing 6 is covered with black velvet 61 to prevent the light source display unit 1 from reflecting light and forming a reflection.

[0080] Base 62 is rotatably connected to outer shell 6.

[0081] Preferably, the outer shell 6 is provided with an upper shell 63 having a window, and light shields 64 are provided on the upper and lower sides of the window position of the upper shell 63 to block external stray light; an retroreflector 4 is provided on the inner side of the rear cover plate of the outer shell 6, and a quarter wave plate 65 is attached to the retroreflector 4.

[0082] Preferably, the inner side of the upper cover plate of the upper shell 63 is provided with black velvet 61; the upper shell 63 and the outer shell 6 are fixed by an embedded screw hole structure 66; the base 62 and the outer shell 6 are connected by a connecting knob structure 67 for rotational connection; the base 62 is provided with a fixing screw hole structure 68 for fixing the base 62.

[0083] The MTF of the suspended image formed by the aerial imaging region 5 can be 35%, 38.5%, or 42%. The Fresnel lens 3 can have a focal length of 150mm to 300mm, a size of 300mm × 300mm, and a thickness of 1mm; the focal length can be 150mm, 225mm, or 300mm. The Fresnel lens 3 can magnify the image beam by 2 to 4 times and image it onto the retroreflector 4.

[0084] like Figures 1-3 As shown, the light source display unit 1 generates an image beam, which is directed towards the tilted beam splitter 2. The beam splitter 2 reflects the image beam to the Fresnel lens 3, which focuses and magnifies the image beam, projecting the magnified image beam onto the surface of the miniature triangular prism array of the retroreflector 4. The retroreflector 4, through the geometric optical characteristics of the miniature triangular prism array, reflects the received image beam back to the Fresnel lens 3 along the original optical path. During this process, the quarter-wave plate 65 optimizes the beam polarization state. The Fresnel lens 3 refracts the reflected image beam again. Since the aerial imaging region 5, the Fresnel lens 3, and the retroreflector 4 form a conjugate symmetric structure, the beam propagates along the phase conjugate reflection optical path, automatically canceling the spherical aberration, chromatic aberration, and distortion generated by the Fresnel lens 3 during propagation. The corrected image beam is directed towards the beam splitter 2, which transmits it to the aerial imaging region 5, ultimately forming a high-definition suspended image. Users can view the image from the viewing position 100.

[0085] like Figure 4 As shown, the principle of traditional retroreflective levitation imaging is as follows: the light beam generated by the traditional light source 101 is reflected by the traditional semi-transparent and semi-reflective film 102 to the traditional retroreflector 103. After the traditional retroreflector 103 reflects the light, a traditional levitation image 104 is formed in the air. This structure lacks aberration correction and efficient focusing components, resulting in defects such as low resolution and stray light interference. Figure 5 As shown, the Fresnel retroreflection conjugate symmetry levitation imaging principle of this invention is as follows: the aerial imaging region 5, the Fresnel lens 3, and the retroreflector 4 form a conjugate symmetry structure, realizing a phase conjugate reflection optical path, providing a principle support for aberration self-elimination, and making the levitation image significantly superior to... Figure 4 The traditional levitation image 104 shown is a traditional retroreflective levitation image.

[0086] Example

[0087] Light source display unit 1: 441PPI, 5-inch OLED display module.

[0088] Beam splitter 2: It adopts a semi-transparent reflective film and is tilted and set in the optical path of the light source display unit 1.

[0089] Fresnel Lens 3: Made of PMMA (polymethyl methacrylate) material, with a focal length of 300mm, dimensions of 300mm×300mm, and a thickness of 1mm.

[0090] Retroreflector 4: It adopts a reflective film with a micro prism array structure and is attached to the inside of the rear cover plate of the outer shell 6; a 1 / 4 wave plate 65 is also attached to the surface of the reflective film.

[0091] Aerial imaging area 5: Located at a position symmetrical to the light source display unit 1 with respect to the beam splitter 2.

[0092] Outer shell 6: used to house the aforementioned core optical components. The inner side of the upper cover plate of the upper shell 63 is covered with black velvet cloth 61, which has high light absorption. The upper shell 63 is fixed to the outer shell 6 by an embedded screw hole structure 66. Light shields 64 are provided on the upper and lower sides of the window of the upper shell 63.

[0093] Base 62: It is rotatably connected to the outer shell 6 through a connecting knob structure 67; the base 62 is also provided with a fixing screw hole structure 68, which can fix the device to a vehicle bracket, medical operating table or advertising display rack by bolts to ensure the stability of the device.

[0094] In the experiment, a 5-inch high-definition suspended image was successfully formed in the aerial imaging area 5 at a distance of 1500mm from the retroreflector 4. The image had sharp text edges, complete graphic details, and no obvious distortion. The MTF was 35% to 42%, which is significantly better than the traditional AIRR system (MTF < 20%).

[0095] In summary, the above description is only a preferred embodiment of the present utility model. All equivalent changes and modifications made within the scope of the patent application of the present utility model shall be covered by the present utility model.

Claims

1. A high-definition retroreflective levitation imaging device based on a Fresnel lens, characterized in that: Including those arranged sequentially along the optical path: The light source display unit (1) is used to generate image beams; A beam splitter (2) is tilted on the optical path of the light source display unit (1) to change the optical path direction of the image beam; A Fresnel lens (3) is placed in the optical path of the beam splitter (2) to focus and magnify the image beam; Retroreflector (4) is placed in the optical path of Fresnel lens (3) to reflect the image beam along the original optical path; The aerial imaging area (5) is located symmetrically to the light source display unit relative to the beam splitter (2) and is used to receive the image beam and form a suspended image.

2. The high-definition retroreflective levitation imaging device based on a Fresnel lens according to claim 1, characterized in that: The aerial imaging region (5), Fresnel lens (3), and retroreflector (4) form a conjugate symmetric structure, which is used to achieve aberration self-elimination of the image beam through the phase conjugate reflection optical path.

3. The high-definition retroreflective levitation imaging device based on a Fresnel lens according to claim 1, characterized in that: The Fresnel lens (3) is made of PC, PMMA or PET.

4. A high-definition retroreflective levitation imaging device based on a Fresnel lens according to claim 1, characterized in that: The retroreflector (4) is a reflective film with a micro prism array structure.

5. A high-definition retroreflective levitation imaging device based on a Fresnel lens according to claim 1, characterized in that: The light source display unit (1) is a liquid crystal display module or an OLED display module.

6. A high-definition retroreflective levitation imaging device based on a Fresnel lens according to claim 1, characterized in that: The MTF of the suspended image formed by the aerial imaging region (5) is 35% to 42%.

7. A high-definition retroreflective levitation imaging device based on a Fresnel lens according to claim 1, characterized in that: The beam splitter (2) is a semi-transparent reflective film used to reflect the image beam emitted by the light source display unit (1) to the Fresnel lens (3); and to transmit the image beam returned by the retroreflector (4) to the air imaging area (5).

8. A high-definition retroreflective levitation imaging device based on a Fresnel lens according to claim 1, characterized in that: Also includes: The outer casing (6) is used to house the light source display unit (1), beam splitter (2), Fresnel lens (3), retroreflector (4), and aerial imaging area (5); the aerial imaging area (5) is located at the window position of the outer casing (6); the inner side of the outer casing (6) is covered with black velvet (61) to prevent the light source display unit (1) from reflecting light and forming a reflection; The base (62) is rotatably connected to the outer shell (6).

9. A high-definition retroreflective levitation imaging device based on a Fresnel lens according to claim 8, characterized in that: The outer shell (6) is provided with an upper shell (63) with a window. A light shield (64) is provided on the upper and lower sides of the window position of the upper shell (63) to block external stray light. An anti-reflector (4) is provided on the inner side of the rear cover plate of the outer shell (6). A quarter wave plate (65) is attached to the anti-reflector (4).

10. A high-definition retroreflective levitation imaging device based on a Fresnel lens according to claim 9, characterized in that: The inner side of the upper cover plate of the upper shell (63) is provided with black velvet (61); the upper shell (63) and the outer shell (6) are fixed by an embedded screw hole structure (66); the base (62) and the outer shell (6) are connected by a connecting knob structure (67) for rotational connection; the base (62) is provided with a fixing screw hole structure (68) for fixing the base (62).

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