A levitation imaging device

Abstract

This utility model discloses a levitation imaging device, including a projector; its characteristic is that the levitation imaging device further includes a projection screen, which is a semi-transparent screen, and the projection screen receives the projected light from the projector to form a levitation real image. Compared with the prior art, the advantages of this utility model are: compared with the levitation images formed by conventional opaque or fully transparent screens or the virtual images formed by transparent screens, this utility model, by making the projection screen semi-transparent and forming a real image, utilizes the principles of the human visual system to achieve a levitation or three-dimensional effect by simulating light and shadow, perspective, and spatial relationships. It also allows for the convenient selection of projection screens with a large scattering field of view, improving display effects and user experience.

Description

Technical Field

[0001] This utility model relates to optical imaging technology, and in particular to a levitation imaging display device. Background Technology

[0002] Existing projection imaging technologies are mainly divided into long-throw projection, short-throw projection, and ultra-short-throw projection (UST). A comparison of these three projection types is shown in Table 1 below:

[0003] Long-throw projector >1.0 >3m Large conference rooms, cinemas Short-throw projectors 0.4~1.0 1~2m Small and medium-sized classrooms Ultra-short throw projector ≤0.4 <0.5m Small apartments, interactive display windows

[0004] Table 1 Comparison of Projection Types

[0005] Among them, the core technological breakthrough of ultra-short throw projection lies in optical path reconstruction:

[0006] 1. Optical path design

[0007] 1.1 Reflective solution: A freeform surface mirror is used to reflect light and project it onto the screen at an angle. Asymmetric curvature is used to compensate for distortion (such as the curved surface phase correction technology of Hitachi HCP-A8).

[0008] 1.2 Concave Lens Solution: Ricoh pioneered the use of concave lens groups to generate an intermediate image, which is then magnified and projected, and combined with a refractive optical system to reduce body size.

[0009] 2. Throw ratio calculation: R = projection distance d / screen width W. For example, to project a 100-inch (width ≈ 2.2m) screen, traditional long-throw projectors require d ≥ 3m (R ≥ 1.5), while ultra-short-throw projectors only require d = 16.8cm (JMGO O2 Ultra, R = 0.18:1).

[0010] Ultra-short throw projection technology has undergone the following evolution and breakthroughs:

[0011] I. Early Exploration (Before the 2010s):

[0012] 1. Fisheye lens solution: shortens the distance with a wide-angle lens, but suffers from severe distortion (barrel distortion > 10%), and only supports a 70-inch projection from 1 meter.

[0013] 2. First-generation reflector projector: The 2012 Yatu RAC100 series achieved a projection of 80 inches from 19.5cm, but the brightness and uniformity were insufficient.

[0014] II. Breakthroughs in Key Technologies (2016 to present):

[0015] 1. Mass production of freeform surface lenses: Hitachi, Ricoh and other manufacturers have overcome the nanoscale surface processing technology and achieved a distortion rate of <2% (such as Ricoh PJWX4130).

[0016] 2. Popularization of tri-color laser light source: In 2023, JMGO O2 will integrate tri-color laser with ultra-short focal length to solve the problem of brightness decay in traditional UST (light loss of 12 lenses is reduced by 30%), with brightness reaching 750~2800 CVIA lumens.

[0017] 3. Intelligent correction system: automatic keystone correction and screen obstacle avoidance (such as Bonfire OS in Smartisan O2), solving installation location limitations.

[0018] III. Analysis of the Core Performance Advantages of Ultra-Short Throw Projectors

[0019] 1. Revolutionary in space:

[0020] 1.1. Wall-mounted projection: The projector can project a 100-inch image with the body 23.8cm away from the wall, and is compatible with a standard TV cabinet with a depth of 40cm, completely freeing up space.

[0021] 1.2. No wiring required: The power supply is directly connected to the TV cabinet socket, avoiding ceiling drilling or long-distance wiring.

[0022] 1.3. Breakthrough in Image Quality:

[0023] 1.3.1. Advantages of three-color laser:

[0024] It covers 110% of the BT.2020 color gamut (Delta E < 1), far exceeding the 90% sRGB of LEDs;

[0025] Selectively avoids harmful blue light wavelengths (425~455nm), providing hardware-level eye protection.

[0026] 1.3.2. Speckle suppression: Nut O2 Ultra uses LSR dynamic speckle elimination technology, with an elimination rate of >98%.

[0027] 1.4. Interaction and Health Experience:

[0028] 1.4.1. No shadow occlusion: There is no light and shadow interference even when the speaker is less than 30cm away from the screen, which is suitable for educational scenarios;

[0029] 1.4.2. Low light stimulation: The angle between the projection path and the line of sight is >60° to avoid direct exposure to the eyes (traditional projection is only 15°~30°).

[0030] A comparison of light source technologies is shown in Table 2 below:

[0031] Traditional LED 90% sRGB 300~400 lumens Contains high-energy blue light 20,000 hours Monochromatic laser 100% DCI-P3 1500 lumens Partial blue light filtering 25,000 hours Tri-color laser 110% BT.2020 750~3600 lumens Avoid harmful blue light range >30,000 hours

[0032] Table 2 Comparison of Light Source Technologies

[0033] IV. Ultra-short throw projection screen

[0034] Ultra-short-throw projection screens are specialized optical screens designed for ultra-short-throw projection devices (such as laser TVs) with a throw ratio ≤0.4. They address core issues such as ambient light interference, narrow viewing angles, and complex installation through precise optical structures. Their design goal is to achieve high brightness, high contrast, and wide viewing angles at extremely short projection distances (typically <50cm). Ultra-short-throw projection screens solve the problem of receiving and reflecting large-angle incident light through directional light path control.

[0035] 1. Light collection and directional reflection:

[0036] 1.1. The projected light enters the screen at a large angle of 20°~80°. The divergent light is converted into parallel reflected light through a micro-convex reflective unit or a sawtooth prism structure, which improves the brightness utilization rate by 30%.

[0037] 1.2. Fresnel lens layer: The ring-shaped textured structure focuses the incident light and reduces scattering loss (light efficiency improvement ≥40%).

[0038] 2. Ambient light suppression:

[0039] The lower sloping surface of the prism layer is coated with a metal reflective layer (aluminum / silver) to directionally reflect projected light, while the upper sloping surface is coated with a black light-absorbing material to absorb ambient light, with a suppression rate of ≥90%.

[0040] 3. Color Enhancement:

[0041] A high-reflectivity metal layer (gain 0.8–1.1) is adapted to the spectral characteristics of the laser source, with a color gamut coverage of ≥110% BT.2020.

[0042] In addition, commonly used levitation imaging can be divided into phase holography, fan holography, Pepper phantom, parallax 3D, negative refraction imaging, etc., based on different imaging principles.

[0043] Phase holography, in a physical sense, refers to a display technology that reproduces the amplitude and phase information of light. This type of solution typically requires a fixed or variable phase plate and utilizes the coherence principle of lasers. The core technologies are coherent light and holograms, which are technically demanding. Currently, due to low technological maturity and high costs, it is far from being commercialized.

[0044] Fan holography is a display solution that uses the rotation of a light-emitting diode (LED) fan and the principle of persistence of vision to create the illusion of an object rotating in the air. Specifically, the system's microprocessor analyzes the driving current signal of each LED on the fan strip based on the desired two-dimensional image information and the position, angle, and rotation speed of each LED. The two-dimensional image information is reproduced as the fan strip completes one rotation cycle. This technology is widely used commercially. The core technical points are the stable rotation control of the fan and the decomposition and analysis of the two-dimensional image. The displayed content requires additional algorithm processing, and there are certain compatibility issues with traditional two-dimensional display signals. Furthermore, the image displayed on the rapidly rotating fan strip does not truly detach from the display carrier, generally requiring structural protection for the fan strip. Therefore, there are significant limitations to interactive gestures and touch controls.

[0045] Pepper's ghost, which has been around for over 100 years, uses a semi-transparent, semi-reflective plane mirror to create a virtual image of an object. Because the semi-transparent mirror doesn't obscure the background, it makes the object appear to float. The core technology lies in the large area of ​​the semi-transparent, semi-reflective plane mirror and the obscuring of the image source. It has been widely used in stage performances where space is not a major constraint. The main problems with this method are its large size and the fact that the resulting phantom image is a virtual image behind a screen.

[0046] Parallax 3D creates the effect of image levitation through binocular parallax. Common 3D movies, lenticular parallax 3D, time-division multiplexing parallax 3D, integrated imaging, and light field displays all fall into this category. This technology is already widely used in 3D technology. For a long time, image splitting algorithms and hardware display effects (focus-convergence conflict, multi-viewpoint, etc.) have been continuously optimized. Generally speaking, the displayed content requires additional algorithmic processing, and there are certain compatibility issues with traditional 2D display signals. Furthermore, the conflict between the image levitation created by parallax and the actual focal plane of the eye (VAC) can induce a certain degree of visual dizziness.

[0047] Negative refractive index imaging utilizes the negative refractive index property of materials for imaging, and is divided into reflection type and transmission type. It's called negative refractive index because when light is reflected and transmitted at the interface of such materials, the reflected and transmitted rays are on the same side of the interface normal as the incident ray, corresponding to a negative refractive index in Fresnel's laws of reflection and transmission. This type of technology is still under development and its market is gradually expanding. The main technical challenge lies in the materials used to achieve negative refractive index; currently announced technologies include reflective mirror arrays and metamaterials.

[0048] For details on the principles of each of the above-mentioned levitation imaging methods, please refer to: https: / / zh.wikiversity.org / zh / %E7%A9%BA%E6%B0%94%E6%98%BE%E7%A4%BA%E5%B1%8F.

[0049] Existing levitation imaging devices based on ultra-short throw projection, such as the levitation imaging display cabinet disclosed in Chinese Patent Application No. 201110426774.7, produce virtual images with a small field of view, resulting in a poor user experience. Utility Model Content

[0050] The technical problem to be solved by this utility model is to provide a levitation imaging device with a large field of view, which improves the display effect and user experience, in order to address the shortcomings of the existing technology.

[0051] The technical solution adopted by this utility model to solve the above-mentioned technical problems is as follows: a levitation imaging device, including a projector; characterized in that: the levitation imaging device further includes a projection screen, the projection screen is a semi-transparent screen, and the projection screen receives the projected light from the projector to form a levitation real image.

[0052] Compared to the floating images formed by conventional opaque or fully transparent screens or the virtual images formed by transparent screens, this invention makes the projection screen semi-transparent and forms a real image. It utilizes the principles of the human visual system to achieve a floating or three-dimensional effect by simulating light and shadow, perspective, and spatial relationships. It also allows for the convenient selection of projection screens with a large scattering field of view, improving the display effect and user experience.

[0053] To reduce the impact of ambient light on the projection screen, a light shield is installed on the projection screen.

[0054] Preferably, the light shield extends laterally to one side from at least the top of the projection screen, and the light shield and the light emission point of the projector are located on the same side of the projection screen.

[0055] Preferably, the light shield is also disposed on opposite sides of the projection screen in the horizontal direction.

[0056] In order to reduce the stray light generated by the projection light passing directly through the projection screen, a light-absorbing cover is provided on the projection screen.

[0057] Preferably, the light-absorbing cover extends laterally to one side from the top of the projection screen, and the light-absorbing cover and the light-emitting point of the projector are located on opposite sides of the projection screen.

[0058] Preferably, the projector is an ultra-short-throw projector, which can significantly reduce the throw ratio through the freeform concave mirror, thus having a compact size. Moreover, since the lens design of the ultra-short-throw projector can be compatible with a certain range of throw ratios, different display screen sizes can be achieved by controlling the distance between the projection screen and the projection lens of the projector, thus having the advantage of strong scalability.

[0059] Compared with the prior art, the advantages of this utility model are as follows: Compared with the floating image formed by conventional opaque or fully transparent screens or the virtual image formed by transparent screens, this utility model makes the projection screen a semi-transparent screen and forms a real image. It uses the principle of the human visual system to simulate light and shadow, perspective and spatial relationships to achieve the floating or three-dimensional effect. It can easily select a projection screen with a large scattering field of view, thereby improving the display effect and user experience. Attached Figure Description

[0060] Figure 1 This is a front view of the levitation imaging device according to an embodiment of the present invention;

[0061] Figure 2 This is a side view of the levitation imaging device according to an embodiment of the present invention. Detailed Implementation

[0062] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions.

[0063] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Since the embodiments disclosed in this utility model can be arranged in different directions, these terms indicating direction are only for illustration and should not be regarded as limitations. For example, "upper" and "lower" are not necessarily limited to directions opposite to or consistent with the direction of gravity. In addition, features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0064] See Figure 1 and Figure 2A levitation imaging device based on ultra-short-throw projection is disclosed. It includes a projector 1 and a projection screen 2. The projector 1 projects images onto the projection screen 2, and is preferably an ultra-short-throw projector 1. The projection screen 2 is a semi-transparent screen. The levitation effect of the displayed image is achieved by simulating light and shadow, perspective, and spatial relationships using the principles of the human visual system. Areas without displayed content are generally displayed against a solid color background. In this embodiment, the projection lens of the projector 1 is lower than the projection screen 2 and located in front of the projection screen 2. Here, "front" refers to the side closer to the user relative to the projection screen 2 when facing it; the "rear" side in the following text is the opposite. Figure 1 and Figure 2 The arrows in the diagram indicate the direction of the projected light rays.

[0065] To reduce the impact of ambient light on the projection screen 2, a light shield 3 is provided on the projection screen 2. The light shield 3 extends laterally from at least the top of the projection screen 2 to one side. Optionally, the light shield 3 extends laterally from opposite sides of the projection screen 2 (e.g., Figure 1 Light shields 3 are also provided on the left and right sides (as shown in the diagram). To reduce stray light generated by the projection light directly passing through the projection screen 2, the levitation imaging device also includes a light absorber 4 disposed on the projection screen 2. The light absorber 4 can extend laterally from the top of the projection screen 2 to the side away from the light shield 3. When the user faces the projection screen 2, the light shield 3 is located on the side facing the user, while the light absorber 4 is located on the side away from the user, and the side of the projection screen 2 facing the user is the front.

[0066] Compared to currently available levitation imaging devices, the solution in this invention allows for the selection of a projection screen with a large scattering field of view (e.g., ≥120°). Compared to the levitation image generated by a virtual image, the image formed in this invention is a real image (the imaging principles of virtual and real images are well-known), offering the advantage of a large field of view. Because projector 1 uses an ultra-short-throw projector, the throw ratio can be significantly reduced through a freeform concave mirror, resulting in a compact size. Furthermore, the lens design of the ultra-short-throw projector can accommodate a certain range of throw ratios. By controlling the distance between the projection screen 2 and the projection lens of projector 1, different display screen sizes can be achieved, thus offering strong scalability.

[0067] This invention provides an optional solution: a 10-inch suspended imaging device, specifically a projection screen 2 with a front diagonal size of 10 inches, an overall reflectivity of 50%, and a front surface with Lambertian scattering (field of view close to 180°, gain of 1). The projection lens of projector 1 has a throw ratio of 0.23:1, and the distance d between the light-emitting point A of the projector 1's lens and the projection screen 2 (typically the geometric center O of the front of the projection screen 2, such as the intersection of the diagonals of a rectangular screen) is 51mm. The projected luminous flux is 52lm. At this point, the projected image size is approximately 221mm * 124mm, and the brightness of the projection screen 2 is calculated as projected luminous flux / (projected area * π) * screen reflectivity * screen gain, approximately 300 nits.

[0068] Another optional solution is to provide a 40-inch suspended imaging device, where the front diagonal size of projection screen 2 is 40 inches, the overall reflectivity of projection screen 2 is 30%, the field of view of projection screen 2 is close to 120°, the gain is 1.5, the projection lens of projector 1 has a throw ratio of 0.25:1, and the distance d between the light emission point A of the projection lens of projector 1 and projection screen 2 (usually the geometric center O of the front of projection screen 2, such as the intersection of the diagonals of a rectangular screen) is 221mm, with a projected luminous flux of 616lm. In this case, the projected image size is approximately 886mm * 498mm, and the brightness of projection screen 2 is calculated as projected luminous flux / (projected area * π) * screen reflectivity * screen gain, which is approximately 200 nits.

Claims

1. A levitation imaging device, comprising a projector (1); characterized in that: The levitation imaging device also includes a projection screen (2), which is a semi-transparent screen. The projection screen (2) receives the projected light from the projector (1) to form a levitation image.

2. The levitation imaging device according to claim 1, characterized in that: A light shield (3) is provided on the projection screen (2).

3. The levitation imaging device according to claim 2, characterized in that: The light shield (3) extends laterally to one side from the top of the projection screen (2), and the light-emitting point of the light shield (3) and the projector (1) are located on the same side of the projection screen (2).

4. The levitation imaging device according to claim 3, characterized in that: The light shield (3) is also provided on opposite sides of the projection screen (2) in the horizontal direction.

5. The levitation imaging device according to claim 1, characterized in that: A light-absorbing cover (4) is provided on the projection screen (2).

6. The levitation imaging device according to claim 5, characterized in that: The light-absorbing mask (4) extends laterally to one side from the top of the projection screen (2), and the light-emitting points of the light-absorbing mask (4) and the projector (1) are located on opposite sides of the projection screen (2).

7. The levitation imaging device according to any one of claims 1 to 6, characterized in that: The projector (1) is an ultra-short throw projector.

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