Micro-prism and black ar composite optical cover plate for aerial imaging

Abstract

The application discloses a micro-prism and black AR composite optical cover plate for aerial imaging and belongs to the technical field of medium-free aerial imaging optical devices. The cover plate is arranged above a flat lens, a glass substrate is divided into an inner bonding surface facing the flat lens and an outer visible surface, the inner bonding surface is provided with a one-way micro-prism optical structure, the two can be closely assembled or an assembly gap for adapting an optical path can be reserved, and the outer visible surface is provided with a multilayer medium interference light extinction black AR antireflection film layer. The micro-prism optical structure has four light field regulation functions: ensuring high transmission of oblique imaging light, shielding the micro-nano texture on the surface of the flat lens by total internal reflection of external vertically incident ambient light, correcting imaging geometric distortion by angle pre-compensation of the light emitted by the flat lens, and widening the effective viewing angle by outward divergence and beam expansion of the edge field of view. The application can obtain a regular and large field of view aerial real image without software pixel correction, has multiple functions of high light transmission, hidden texture, outer visible pure black appearance effect, distortion correction and large viewing angle, and can be applied to various aerial imaging devices for vehicles, households and businesses.

Description

Technical Field

[0001] This invention belongs to the field of medium-free aerial imaging optical device technology. Specifically, it is a universal protective cover plate that is matched with a flat plate lens, has high light transmittance, hides the micro-nano texture of the flat plate lens, has a pure black appearance, hardware corrects imaging distortion, and widens the viewing angle. It can be widely used in various aerial imaging devices such as vehicle instrument imaging, home desktop holographic projectors, and commercial holographic display cabinets in stores. Background Technology

[0002] The mature optical path structure for medium-free aerial imaging is as follows: a flat plate lens is placed horizontally, and a display is set below the flat plate lens, with the display panel at a 45° angle to the horizontal flat plate lens; light rays are emitted perpendicularly from the display panel, enter the horizontal flat plate lens, and undergo two negative refractions and two internal reflections by the flat plate lens to complete the optical field reconstruction, forming a real image in the air.

[0003] This flat lens has four types of inherent defects that cannot be avoided: Severe imaging distortion: The two layers of optical waveguides inside the flat lens are arranged orthogonally. After the light rays from pixels in different fields of view pass through the two layers of negative refraction structure, nonlinear optical path shift occurs, resulting in trapezoidal and pincushion stretching distortion in the image. The industry's conventional solution is to use screen software algorithms to stretch pixels for compensation, which will crop the image edges, lose the original resolution, and increase the computing power consumption of the main control chip. The effective viewing angle is narrow: the flat lens has extremely high light loss of large-angle edge beams, and only the central narrow area is clear and bright. After the human eye shifts slightly left, right or up and down, the edge of the image quickly darkens and blurs, resulting in a poor human-computer interaction experience. Exposed surface texture of flat plate lens: Flat plate lens has a periodic micro-nano structure. After light scattering, the texture can be clearly observed from the outside of the device, and the viewing window looks messy and lacks refinement. The visible area of ​​the device is transparent and bright: Without a matching black cover, the exposed visible area of ​​the flat lens is transparent and bright, which is visually disconnected from the black casing of the whole machine and cannot meet the requirements of terminal manufacturers for an integrated pure black appearance design.

[0004] Existing mainstream solutions on the market all have significant shortcomings and cannot simultaneously resolve all the above-mentioned defects: Only the outer side is coated with ordinary AR anti-reflective glass: it only slightly reduces surface reflection, has no internal light-blocking and light field control structure, the flat lens texture is fully exposed, and there is no distortion correction or widening of the viewing angle function; External polarizer: Relying on organic dye to absorb light to achieve a black appearance, the light transmittance of the image is greatly reduced. The polarizer cannot cancel the scattering pattern of the flat lens. It is prone to whitening, warping and failure when placed in high and low temperatures in the vehicle or in long-term indoor placement. Conventional one-way microprism film / cover plate: It only has the function of general privacy protection and light beam convergence, and is not adapted to the imaging optical path of this 45° angled flat lens. It will further compress the effective viewing angle and does not have the ability to pre-compensate for imaging distortion. At the same time, it does not have a matching multi-layer dielectric interference extinction black AR film, so the lens viewing window cannot present a uniform pure black visual effect.

[0005] Metal one-way vision coated glass: The metal coating absorbs a large amount of imaging light, resulting in a low upper limit of light transmission. Under strong light, it produces a mirror ghost image. When the internal brightness is higher than the external brightness, perspective reversal occurs, and the texture of the flat lens is fully exposed.

[0006] For a long time, it has been widely believed in the field that there is a fundamental contradiction between the "pure black appearance for light blocking" and the "high transmission of imaging light" of aerial imaging cover plates, and that light blocking inevitably comes at the cost of light transmittance. Therefore, existing solutions either choose to sacrifice appearance for light transmission (ordinary AR glass) or sacrifice light transmission for appearance (polarizers / metal coatings), and no single cover plate solution has been found that can simultaneously satisfy multiple functions such as high light transmittance, pure black appearance, texture masking, distortion correction, and wide viewing angle.

[0007] To address this, the present invention proposes a microprism and black AR composite optical cover for aerial imaging. Through the synergistic cooperation of a unidirectional microprism array optical structure and a multilayer dielectric interference extinction black AR antireflection film, multiple technical problems are solved simultaneously, including high light transmittance imaging, permanent masking of flat lens texture, pure black appearance, hardware correction of imaging distortion, and widening of viewing angle. Summary of the Invention

[0008] Purpose of the invention Overcoming the shortcomings of existing flat-panel lens imaging systems, such as insufficient light transmission, inability to permanently cover the micro-nano textures of flat-panel lenses, difficulty in achieving uniform pure black appearance, severe imaging distortion, narrow effective viewing angle, limited applicable scenarios, and poor weather resistance, this invention provides a composite optical cover plate of a microprism and black AR for aerial imaging. This invention is not limited to a certain set of fixed dimensions and optical parameters. As long as all parameters are within a reasonable range, it can meet all usage requirements. It is also compatible with various aerial imaging devices such as automotive, home consumer, and commercial display devices, and simultaneously achieves comprehensive performance including high light transmission imaging, no texture leakage, pure black front, hardware correction of image distortion, significantly widened viewing angle, stable day and night effects, and resistance to environmental aging. Technical solution

[0009] Referring to Figure 1, the present invention discloses a microprism and black AR composite optical cover plate for aerial imaging, with a glass substrate labeled 2 as the base; the outer visible surface of the glass substrate is provided with a multilayer dielectric interference extinction black AR antireflection film labeled 1, and the inner bonding surface of the glass substrate facing the flat lens is formed with a unidirectional microprism optical structure labeled 3.

[0010] The glass substrate is divided into an inner bonding surface facing the flat lens and an outer visible surface facing outward. The inner bonding surface is the mating side of the substrate facing the flat lens, which is only used to distinguish the inner and outer orientations and is not forced to be in close contact with the flat lens. An optical cover plate is arranged above the flat lens. The unidirectional microprism array optical structure labeled 3 is parallel to the flat lens. The two can be tightly fitted together or have a reserved assembly gap for adapting the optical path. The assembly gap for adapting the optical path refers to the air gap that can ensure high transmission of oblique imaging, stably shield the micro-nano texture of the flat lens, correct imaging distortion, and widen the viewing angle. If the gap size is too large, it will generate stray light from multiple interfaces and attenuate the image quality, making it impossible to achieve all the optical functions of the present invention, and is not a suitable assembly form of the present invention.

[0011] In the overall optical path, the display is positioned below the flat lens, with the display panel at a 45° angle to the flat lens. The imaging light rays emitted from the flat lens are obliquely incident on the unidirectional microprism array. The unidirectional microprism array, relying on the differential refraction of its multiple sets of tilted prism working surfaces, possesses the following light field control functions: (1) The oblique imaging light rays pass through the microprism smoothly, with only extremely low interface reflection loss, ensuring high light transmittance in imaging; (2) External ambient light incident vertically undergoes total internal reflection at the microprism structure, locking the micro-nano scattered light and dark light generated by the flat lens inside the cover plate and preventing it from passing out. (3) Perform reverse angle pre-compensation on the pixel light emitted from the flat lens to offset the nonlinear optical path offset caused by the two layers of orthogonal negative refraction and eliminate trapezoidal and pincushion imaging distortion; (4) Apply outward divergence refraction to the large-angle field of view beam at the edge to balance the light flux of the entire field of view and widen the effective viewing window of the whole machine in both horizontal and vertical directions.

[0012] The multilayer dielectric interference matting black AR antireflective coating (labeled 1) achieves a pure black appearance on the outside by canceling ambient light reflection through multilayer interference of inorganic media with high and low refractive indices, without absorbing imaging light. The glass substrate has high flatness, which ensures that no optical path distortion occurs when the cover plate and the flat lens are arranged opposite each other.

[0013] Beneficial effects 1. The product is highly versatile and has a wide range of applications. The core structure of this invention adopts a universal design, with reasonable applicable ranges set for the microprism tilt angle, array period, substrate thickness, and number of black AR film layers. Within these ranges, any product of any specification can stably achieve all optical functions, including high light transmittance, lens texture masking, distortion correction, widened viewing angle, and a pure black viewing window. It can flexibly match different specifications of flat lens and is suitable for various aerial imaging devices, including automotive, home, and commercial applications. With a multi-layer optimized solution, it can meet the differentiated performance requirements of different products.

[0014] 2. Targeted optimization of the optical path, providing a one-stop solution to multiple inherent defects. The microprism structure is designed specifically for imaging optical paths where the display and flat panel lens are at a 45° angle. A single set of microstructures can simultaneously improve three major industry pain points: exposed lens texture, imaging distortion, and narrow viewing angle.

[0015] 3. Physical light-blocking long-lasting hidden lens micro-nano texture Physical light-blocking and isolation are achieved through total internal reflection of light, eliminating the need for light-absorbing materials. Regardless of whether it is a strong light during the day or a weak light at night, there will be no perspective reversal, and the periodic micro-nano textures on the surface of the flat lens can be stably blocked for a long time.

[0016] 4. Balancing the pure black appearance of the viewing window with high imaging light transmission A multi-layer dielectric interference extinction scheme is used to achieve a pure black window effect; the preferred implementation method of pure inorganic and metal-free film layer does not absorb imaging light, thus fundamentally solving the technical contradiction in the industry that "a black appearance will inevitably reduce the imaging transmittance".

[0017] 5. Hardware pre-compensation corrects distortion, saving equipment computing power. By using microprisms to pre-compensate the angle of the imaging light, trapezoidal and pincushion distortions caused by flat lens are offset at the optical path level. This eliminates the need for software pixel stretching compensation, fully preserves the original image resolution, and reduces the computational load on the device's main control chip.

[0018] 6. The effective viewing angle is significantly widened, resulting in a better imaging experience. The microprism disperses the light beam from the edge field of view outward, balancing the light flux across the entire field of view; when users observe from multiple angles, the image remains complete, uniform, and bright, greatly improving the human-computer interaction experience.

[0019] 7. Excellent weather resistance, stable for long-term use in various scenarios. The substrate uses chemically tempered glass combined with an all-inorganic film layer; automotive products can withstand high and low temperature cycling shocks, and household and commercial products are less prone to failure problems such as whitening, peeling, and discoloration of the film layer when used at room temperature for a long time.

[0020] 8. The preferred solution produces pure image quality without stray light. When using a pure inorganic dielectric film layer without metal coating, there will be no specular ghosting or stray light interference, and the color and contrast of the aerial image can be completely preserved. Attached Figure Description

[0021] Figure 1 is a schematic diagram of the layered cross-sectional structure of the optical cover plate of the present invention.

[0022] Figure labels: 1-Multilayer dielectric interference matting black AR antireflective film; 2-Glass substrate; 3-One-way microprism optical structure. Detailed Implementation

[0023] The present invention will be described in detail with reference to Figure 1. Example

[0024] This embodiment provides a microprism and black AR composite optical cover for aerial imaging, including a glass substrate (reference 2); the outer visible surface of the glass substrate is coated with a multilayer dielectric interference black AR antireflective film (reference 1); and the inner bonding surface of the glass substrate facing the flat lens is imprinted with a unidirectional microprism optical structure (reference 3).

[0025] In this embodiment, the cover plate is mounted above the flat lens, with its inner mating surface parallel and opposite to the flat lens. The two can be tightly fitted together, or an assembly gap can be reserved to accommodate the optical path. This assembly gap is designed to ensure high transmission for oblique imaging, stably shield the micro-nano texture of the flat lens, correct imaging distortion, and widen the viewing angle. If the gap is too large, it will generate stray light from multiple interfaces and degrade image quality, failing to achieve all the optical functions of this invention and thus not belonging to the suitable assembly form of this invention.

[0026] The substrate is 2mm low-iron ultra-white float glass, double-sided high-precision grinding, with a TTV flatness of 0.002mm, and chemical tempering with potassium nitrate molten salt at 420℃ for 4.5h. The inner bonding surface of the glass adopts a unidirectional microprism array formed by UV nanoimprinting of a metal master with a period of 90μm and an inclination angle of 40°, with a UV curing energy of 900mJ / cm² at 365nm, and plasma cleaning to remove residual adhesive. A single layer of SiO2 antireflective film is deposited on the inner side. The outer visible surface is deposited with TiO2 and SiO2 media alternately by high vacuum magnetron sputtering, totaling 12 layers of multilayer dielectric interference matting black AR film, without any metal target material.

[0027] In this embodiment, the tilt angle of the microprism is set to 40°, which is adapted to the exit angle of the light after the light is modulated by the flat lens when the display and the flat lens are at a 45° angle. This ensures that the imaging light enters the inclined surface of the microprism at a near-vertical angle, thereby avoiding total internal reflection and ensuring high transmission.

[0028] Optical performance tests were conducted on the sample in this embodiment, and the measured indicators are as follows: The oblique incident visible light transmittance is 91.2%, the average ambient reflectance on the outer side is 0.26%, and the cover plate haze is 41. At a conventional observation distance of 30cm, the micro-nano texture of the rear flat lens cannot be distinguished by the human eye.

[0029] Distortion comparison test: Without this cover plate, the geometric distortion of the flat lens image is 5.9%; after installing this cover plate, the distortion is reduced to 0.92%, and there is no stretching deformation at the four corners of the image.

[0030] Viewing angle comparison test: The original system without the cover plate had an effective horizontal viewing angle of 22°; after adding this cover plate, the horizontal viewing angle reached 29°, an improvement of 31.8%, and the vertical viewing angle was widened simultaneously, with no blackening or blurring at the edges of the screen.

[0031] Vehicle-mounted high and low temperature weathering test: The single cycle conditions are -40℃ for 2 hours and 85℃ for 2 hours. After 500 cycles of hot and cold, the film layer has no problems of blistering, peeling, or whitening. The light transmittance and reflectance indicators fluctuate by no more than 1.2%.

[0032] Example 2 The substrate thickness is 2mm, and the TTV flatness is 0.002mm; the inner microprism tilt angle is 39°, the array period is 88μm, and the UV curing energy is 850mJ / cm²; 11 layers of inorganic dielectric matte black AR film are deposited on the outer side; the remaining processing steps are completely consistent with Example 1. Measured optical data: oblique light transmittance 90.7%, average outer reflectance 0.29%, haze 40; distortion, viewing angle optimization effect, and black uniformity are completely consistent with Example 1, meeting all usage indicators.

[0033] Comparative Example 1 (only the outer side is coated with a black AR film, without microprism optical structure) The same 2mm glass substrate is coated with 12 layers of dielectric matte black AR film on the outside and has no microprism array on the inside. Test results: oblique light transmittance is 84.7%, front reflection is 0.28%, the micro-nano texture of the flat lens is clearly visible, and there is no distortion correction or widening of the viewing angle effect.

[0034] Comparative Example 2 (Conventional 18° tilt microprism, without outer matte black AR film) The inner side is imprinted with an 18° tilted microprism array, while the outer side is coated with only a single layer of ordinary AR anti-reflective film; test results: oblique light transmission 83.1%, frontal ambient reflection 2.7%, the cover plate is generally transparent, the texture of the flat lens can be clearly distinguished, the microprisms concentrate the light, and the viewing angle is further reduced.

[0035] This invention is not limited to the above embodiments and comparative examples. Any equivalent technical solution obtained by conventionally replacing or simply modifying the substrate thickness, microprism parameters, and number of film layers based on the technical concept disclosed in this invention shall fall within the protection scope of this invention.

[0036] Industrial applicability The microprism and black AR composite optical cover plate for aerial imaging provided by this invention can be widely used in various media-free aerial imaging devices such as vehicle-mounted instrument aerial imaging equipment, home desktop holographic projectors, and commercial holographic display cabinets. The product uses an all-inorganic film layer combined with chemically tempered glass. The vehicle-mounted version can withstand high and low temperature cycling aging, while the consumer and commercial version has stable performance during long-term use at room temperature, and has extremely high industrial application value and market prospects.

Claims

1. A microprism and black AR composite optical cover for aerial imaging, characterized in that: Including glass substrate; The glass substrate is divided into an inner bonding surface for facing the flat lens and an outer visible surface facing outward. The inner bonding surface is formed with a unidirectional microprism optical structure, which faces the flat lens and is arranged parallel to it. The two can be tightly fitted together or have a reserved assembly gap to adapt to the optical path. It has the following light field modulation functions: (1) Maintain high transmission for imaging rays incident at an oblique angle; (2) Total internal reflection of ambient light incident perpendicularly from the outside is used to block light and thus shield the micro-nano texture on the surface of the flat lens; (3) Perform angle pre-compensation on the imaging light rays emitted through the flat lens to correct the geometric distortion of the image; (4) Expand the beam outward from the edge of the field of view to broaden the effective viewing angle; The outer visible surface is provided with a multi-layer dielectric interference matte black AR anti-reflection film layer; the multi-layer dielectric interference matte black AR anti-reflection film layer relies on multi-layer optical interference to cancel the reflection of visible light across the entire wavelength range, so that the outer visible surface of the cover plate presents a pure black visual effect.

2. The microprism for aerial imaging and the black AR composite optical cover plate according to claim 1, characterized in that: The inner bonding surface is also provided with an anti-reflective film layer.

3. The microprism for aerial imaging and the black AR composite optical cover plate according to claim 1, characterized in that: The surface of the multilayer dielectric interference matte black AR antireflective film is provided with an anti-fingerprint coating.

4. The microprism for aerial imaging and the black AR composite optical cover plate according to claim 1, characterized in that: The glass substrate is made of low-iron ultra-white float glass through chemical tempering. The substrate has high flatness, which can avoid optical path distortion when the cover plate and the flat lens are arranged opposite each other.

5. The microprism for aerial imaging and the black AR composite optical cover plate according to claim 4, characterized in that: The thickness of the glass substrate is 0.3-5.0 mm, and the flatness of the glass substrate (TTV) is ≤0.003 mm.

6. The microprism for aerial imaging and the black AR composite optical cover plate according to claim 1, characterized in that: The unidirectional microprism optical structure is an array structure integrally formed by UV nanoimprinting. The tilt angle of the tilted working surface of a single microprism is in the range of 30° to 55°, and the period of the microprism array is in the range of 50μm to 200μm. The refractive index of the inclined surface of the microprism is matched with that of the glass substrate. After the external perpendicularly incident ambient light reaches the sidewall of the microprism, it meets the condition of total internal reflection, blocking the micro-nano scattered light from the flat lens from passing outward.

7. The microprism for aerial imaging and the black AR composite optical cover plate according to claim 1, characterized in that: The multilayer dielectric interference matting black AR antireflective film is formed by alternating deposition of inorganic media with high and low refractive indices, without the addition of metal coatings or colored light-absorbing dyes throughout the process.

8. The microprism for aerial imaging and the black AR composite optical cover plate according to claim 1, characterized in that: The cover plate's optical performance meets the following requirements: the visible light transmittance of obliquely incident imaging rays is not less than 90%, the average ambient light reflectance of the outer visible surface is less than 0.3%, and the cover plate's haze range is 35-45; at a conventional observation distance of 30cm, the human eye cannot distinguish the surface micro-nano textures of the rear flat lens.

9. The microprism for aerial imaging and the black AR composite optical cover plate according to claim 1, characterized in that: The unidirectional microprism optical structure modulates the light rays in the central and edge fields of view through differentiated inclined plane refraction. After pre-compensation with a cover plate, the geometric distortion of the flat lens imaging is controlled within 1%, and the effective horizontal and vertical viewing angles of the whole machine are improved by more than 30% compared with the solution without a cover plate.

10. A medium-free aerial imaging system, characterized in that: The device includes a display, a flat panel lens, and an optical cover plate as described in any one of claims 1 to 9; the optical cover plate is arranged above the flat panel lens, with its inner mating surface facing the flat panel lens, and the two are parallel and opposite to each other, allowing for tight fitting and assembly, or allowing for a pre-reserved assembly gap to adapt to the optical path; the display is located below the flat panel lens and its surface forms a 45° angle with the flat panel lens, and the light is modulated by the flat panel lens to form a real image in the air. The medium-free aerial imaging system can be any one of vehicle-mounted imaging equipment, home desktop aerial imaging equipment, or commercial holographic display equipment.

Images