Miniaturized free-space stereoscopic display device for consumer applications

Abstract

This invention discloses a miniaturized, media-free stereoscopic display device for consumer applications. The device integrates a sound field control module and a laser excitation module into a compact housing, offering a portable form factor suitable for single-person or desktop use. Unlike media-free holographic projection schemes that rely on optical micromirror structures or nanoscale optical materials, this device generates a visible stereoscopic image in the target spatial domain through sound field gating and laser ionization of air. The effective imaging area is a spatial range of at least 5 cm from the top of the housing. The device is configured with multiple operating modes, including at least a low-power mode and a standard display mode. The control module automatically adjusts at least one parameter among the overall power consumption, average laser power, and effective imaging area based on the currently selected operating mode. The device meets the safety requirements of Class 1 laser products in the IEC 60825-1 standard, achieving dynamic safety protection through a multi-sensor fusion safety module. It is suitable for consumer-grade scenarios such as home, office, portable communication, and shopping mall displays.

Description

Technical Field

[0001] This invention relates to three-dimensional display and human-computer interaction technology, specifically to a miniaturized, media-free stereoscopic display device for consumer-grade scenarios such as home, office, portable communication, and shopping mall displays. Background Technology

[0002] In the field of consumer display and human-computer interaction, with the increasing demand for remote communication, virtual conferencing and personal entertainment, users urgently need a miniaturized device that can break through the limitations of traditional screens and directly present three-dimensional images in the air.

[0003] In the existing technology, there are multiple technical approaches in the field of media-free stereoscopic displays. Patent document CN111239236B discloses an air ionization display device that uses a multi-beam intersection ionization scheme. However, its architecture includes components such as beam combiners and time delay lines, and the system complexity increases significantly with the number of beams. It is mainly geared towards large-scale application scenarios and does not consider the miniaturization requirements of consumer applications. Patent document CN223612068U discloses a portable display device based on media-free holographic projection. However, its core imaging principle relies on optical micromirror structures and nanoscale optical materials, resulting in a relatively large device size. It also depends on a physical medium and cannot achieve true pure air ionization display. Patent documents CN115442585A and CN115733882A disclose holographic streaming media processing methods and holographic communication methods, respectively. However, their focus is on network transmission protocols and video encoding and decoding, rather than the implementation of display hardware. Furthermore, existing medium-free display solutions based on single-beam femtosecond laser plasma scanning employ a single focal point for serial scanning in three-dimensional space, resulting in an inherent contradiction between imaging size and refresh rate. Moreover, their power consumption and size design are geared towards laboratory or large-scale performance scenarios, without considering the needs of consumer-grade portable devices for low power consumption, miniaturization, and multi-mode adaptive operation.

[0004] From the perspective of actual needs in consumer applications, existing media-free 3D display technologies have the following areas for improvement: Existing air ionization display solutions are mainly geared towards large-scale performances and exhibitions, resulting in large device sizes, high power consumption, and high costs, failing to consider the miniaturized and low-power consumer-grade design requirements; Existing portable display devices rely on optical micromirror structures or nanoscale optical materials, exhibiting media dependence, and their imaging principles are fundamentally different from those of sound field gating combined with laser ionization of air solutions; Existing safety mechanisms are mostly designed with fixed parameters, failing to consider the dynamic safety protection needs of consumer-grade devices in various usage scenarios; Furthermore, consumer-grade products have higher safety requirements, needing to ensure absolute eye safety from a physical perspective, rather than solely relying on detection-response software logic.

[0005] In view of the above-mentioned areas for improvement, this invention proposes a miniaturized, low-power, multi-mode adaptive consumer-grade media-free stereoscopic display device. Summary of the Invention

[0006] This invention aims to provide a miniaturized, medium-free holographic display device for consumer applications. Based on the principle of air emission through acoustic field gating and laser ionization, the device integrates core technology components (ultrasonic phased array, femtosecond laser, optical beam splitter, and control circuitry) into a compact housing, offering a portable form suitable for single-person or desktop use. Unlike medium-free holographic projection schemes that rely on optical micromirror structures or nanoscale optical materials, this device directly generates visible holographic images through acoustic field gating and laser ionization of air.

[0007] The device is configured with multiple operating modes, including at least a low-power mode and a standard display mode. The control module automatically adjusts the device's overall power consumption, average laser power, and at least one parameter in the effective imaging area based on the currently selected operating mode. Through its built-in image acquisition and network communication modules, it supports local-to-local and remote-to-local stereoscopic image generation. The device meets the Class 1 laser product requirements of the IEC 60825-1 standard and is equipped with multiple safety protection measures. The device's overall power consumption is automatically adjusted according to the operating mode, and it supports USB-C interface power supply or built-in battery power supply, meeting the daily usage needs of consumer-grade products.

[0008] (A) Sound Field Control Module: The sound field control module comprises multiple miniature piezoelectric ultrasonic transducer units, at least eight in total, with an operating frequency of not less than 40 kHz and a single transducer unit size not exceeding 10 mm. Each unit is integrated onto the same substrate using MEMS technology and arranged in a planar array. By independently controlling the emission phase and amplitude of each transducer unit, a programmable spatial sound pressure distribution is formed in the target airspace.

[0009] (B) Laser Excitation Module: The laser excitation module includes at least one micro-pulse laser source with an output wavelength in the eye-safe range (1400nm to 3000nm), preferably 1560nm. The single-pulse energy does not exceed 5μJ, and the average power is dynamically adjusted according to the operating mode. For example, it operates at lower power in low-power mode to extend battery life, and automatically increases power in standard display mode to meet display brightness requirements, but always remains below a preset safe power threshold. The optical beam splitter is a diffraction beam splitting element integrated on a chip, dividing the laser pulse into at least four sub-beams. The power level of each sub-beam propagating independently at a non-target location is lower than the emission limit of Class 1 laser products specified in IEC 60825-1.

[0010] (C) The control module performs spatiotemporal synchronous control of the sound field modulation module and the laser excitation module, enabling the laser pulse to selectively trigger ionization in areas of high sound pressure density, generating visible light spots. The overall power consumption of the device is automatically adjusted according to factors such as the working mode, the complexity of the displayed content, and the ambient light intensity, without requiring manual settings by the user. Its design principle is to optimize energy efficiency while meeting the performance requirements of different scenarios, making it particularly suitable for battery-powered portable scenarios.

[0011] (D) Image Acquisition and Communication Module: The image acquisition module is used to acquire the user's 3D image information in real time. The network communication module is used for data interaction with remote devices. The control module generates corresponding 3D scanning path instructions based on the acquired 3D image information or the received remote stereoscopic image data.

[0012] (E) Safety Module: The safety module includes at least two of the following: an infrared thermal imaging sensor, a physical obstruction sensor, and an accelerometer. The infrared thermal imaging sensor is used to monitor the temperature distribution of the target airspace in real time, the physical obstruction sensor is used to detect whether an object has entered a preset safe distance, and the accelerometer is used to detect the movement of the device itself. When an anomaly is detected, the control module switches all sub-beams to a diverging state within no more than 10 microseconds.

[0013] (F) Multi-mode Adaptive Operation: The device is configured with multiple operating modes, including at least a low-power mode and a standard display mode. In low-power mode, the control module adjusts the average laser power and effective imaging area to a lower level to extend battery life. In standard display mode, the control module automatically increases the average laser power and expands the effective imaging area to meet the brightness requirements of the stereoscopic image. This multi-mode adaptive operation design allows the device to automatically balance battery life and display quality without requiring manual user settings.

[0014] (G) Acoustic field isolation structure: Acoustic field isolation structure can be further provided between adjacent transducer units. The acoustic field isolation structure is used to prevent the acoustic field focus of adjacent transducer units from interfering with each other. It can be achieved by physical isolation, anti-phase sound wave cancellation or other equivalent methods. Attached Figure Description

[0015] Figure 1 This is an isometric schematic diagram of the overall appearance of the device. In the figure: 201 - shell, 202 - heat dissipation structure, 203 - ultrasonic transducer array (located inside the shell, indicated by dashed lines), 204 - laser emission window, 205 - image acquisition module, 206 - stereoscopic image in the target airspace.

[0016] Figure 2This is a side view of the internal structure of the device. In the figure: 301 - housing, 302 - MEMS ultrasonic transducer array, 303 - miniature femtosecond laser, 304 - optical beam splitter, 305 - MEMS micromirror scanning module, 306 - control circuit board, 307 - network communication module, 308 - battery module.

[0017] Figure 3 This diagram illustrates various consumer application scenarios. In the diagram: 401 – Home scenario, 402 – Office scenario, 403 – Shopping mall display scenario. Detailed Implementation

[0018] In one embodiment, the device's housing dimensions range from 8 cm to 20 cm (length) × 5 cm to 15 cm (width) × 2 cm to 8 cm (thickness), and its weight ranges from 500 g to 3 kg. The ultrasonic transducer array is a planar array consisting of at least 64 miniature piezoelectric units, operating at a frequency of 40 kHz. The laser source is a 1560 nm femtosecond fiber laser with a single pulse energy of 1 to 5 μJ and an average power of 200 to 500 mW. The device supports USB-C power delivery (20 W to 65 W) and a built-in battery (approximately 1 to 3 hours of battery life).

[0019] During operation, the user places the device on a desktop or uses it handheld. The device captures real-time 3D image information of the user or target object through the image acquisition module. The control module converts this information into scanning path commands, driving the sound field modulation module and laser excitation module to generate corresponding 3D stereoscopic images in the target airspace above the device. Simultaneously, the device can receive 3D image data from remote devices via the network communication module, generating stereoscopic images of remote users in the local airspace. The sensors in the safety module continuously monitor the temperature distribution, physical obstruction, and movement status of the target airspace. When an anomaly is detected, the control module switches all sub-beams to divergent mode within 10 microseconds and reduces the laser power below the safety threshold.

[0020] The differences between this solution and existing technologies, compared to the solution in CN111239236B, are as follows: the number of ultrasonic transducers is reduced to at least 8, the average laser power is reduced to below 500mW, it is designed for consumer-grade miniaturized scenarios rather than large performance venues, and it does not include a beam combiner or an independently adjustable active time delay line. Compared to the solution in CN223612068U, the core imaging principle of this solution is sound field gating and laser ionization of air, rather than relying on optical micromirror structures or nanoscale optical materials. Compared to existing medium-free display solutions based on single-beam femtosecond laser plasma scanning, this solution adopts a modular, layered, parallel scanning approach at the system architecture level, fundamentally overcoming the inherent contradiction between imaging size and refresh rate in single-beam scanning. Compared to existing sound field display solutions using large ultrasonic transducer arrays, this solution miniaturizes and integrates transducer units onto a single chip substrate using MEMS technology, achieving a consumer-grade portable form factor. Compared to existing fixed-parameter safety solutions, this solution achieves dynamic safety protection for portable scenarios through multi-sensor fusion. Compared with existing fixed-parameter power management solutions, this solution achieves a dynamic balance between battery life and display effect by automatically adjusting power consumption, laser power and imaging area according to the currently selected working mode through a multi-mode adaptive working mode.

[0021] This solution maintains internal consistency with the technical approach of the basic patent, but achieves protection coverage for different application scenarios by differentiating parameter ranges: the basic patent is geared towards large-scale performances and exhibitions, while this solution is geared towards consumer-grade scenarios such as home use, office work, portable communication, and shopping mall displays. The two patents share the same core inventive concept, but there are clear distinctions in parameter ranges and specific implementation methods.

Claims

1. A miniaturized, media-free stereoscopic display device for consumer applications, characterized in that, include: case; A sound field control module, housed within the housing, comprises multiple miniature piezoelectric ultrasonic transducer units. Each unit independently controls the emission phase and amplitude to create a programmable spatial sound pressure distribution in the target airspace, reducing the air ionization threshold at at least one target location through localized air density variations. A laser excitation module, also housed within the housing, includes at least one miniature pulsed laser source and an optical beam splitter. The output center wavelength of the pulsed laser source is within the human eye-safe band, with a single pulse energy not exceeding 10 μJ. The average power is dynamically adjusted according to the operating mode and does not exceed a safe power threshold. The optical beam splitter divides the laser pulse into multiple sub-beams, each with an independent beam-emitting unit for directional propagation. The power level of any sub-beam propagating alone at a non-target location is lower than the standard air ionization threshold at that location and lower than the IEC standard air ionization threshold. The Class 1 laser products specified in standard 60825-1 can reach the emission limit; the control module is used to control the spatial update timing of the sound pressure distribution by the sound field modulation module and synchronize the timing of the spatial scanning of each sub-beam by the laser excitation module, so that the laser pulse selectively triggers ionization at the target position to generate a visible light spot; the housing has a portable form that can be used by a single person or on a desktop. The device does not rely on optical micromirror structures or nanoscale optical materials as imaging media.

2. The apparatus according to claim 1, characterized in that, The number of the micro piezoelectric ultrasonic transducer units is at least 8, the operating frequency is not less than 40kHz, the size of a single transducer unit is not more than 10 mm, and the units are integrated on the same substrate using MEMS technology and arranged in a planar array.

3. The apparatus according to claim 1, characterized in that, The micro-pulse laser source is a femtosecond fiber laser with fiber-coupled output, the pulse width is adjustable in the range of 50 to 500 femtoseconds, the single pulse energy does not exceed 5μJ, and the average power does not exceed 500mW; the optical beam splitter is a diffraction beam splitter element integrated on a chip, which divides the laser pulse into at least 4 sub-beams.

4. The apparatus according to claim 1, characterized in that, The housing is equipped with a heat dissipation structure, and the overall power consumption of the device is automatically adjusted according to the working mode. It supports power supply via USB-C interface or built-in battery.

5. The apparatus according to claim 1, characterized in that, It further includes an image acquisition module, which is disposed on the housing, for acquiring the user's three-dimensional image information in real time; the control module generates a corresponding three-dimensional scanning path instruction based on the three-dimensional image information, and drives the sound field control module and the laser excitation module to generate a stereo image corresponding to the user in the target spatial domain.

6. The apparatus according to any one of claims 1 to 5, characterized in that, The device is configured with multiple operating modes. The control module automatically adjusts at least one parameter of the device's overall power consumption, average laser power, and effective imaging area according to the currently selected operating mode. The operating modes include at least a low-power mode and a standard display mode, wherein the average laser power and effective imaging area in the low-power mode are both smaller than those in the standard display mode.

7. The apparatus according to claim 1, characterized in that, The device further includes a safety module comprising at least two of an infrared thermal imaging sensor, a physical obstruction sensor, and an accelerometer. The infrared thermal imaging sensor is used to monitor the temperature distribution of the target airspace in real time, the physical obstruction sensor is used to detect whether an object enters a preset safe distance, and the accelerometer is used to detect the movement state of the device itself. Based on the detection results of the safety module, the control module automatically adjusts the laser power or suspends transmission when an anomaly is detected.

8. The apparatus according to claim 7, characterized in that, When the safety module detects an anomaly, the control module switches all sub-beams to divergent state within 10 microseconds and reduces the laser power below the safety threshold.

9. The apparatus according to claim 1, characterized in that, It further includes a network communication module for data interaction with remote devices; the control module drives the sound field modulation module and the laser excitation module to generate corresponding stereo images in the local target airspace based on stereo image data from the remote devices.

10. The apparatus according to claim 1, characterized in that, The light spot generation method in the target space is high-speed point scanning, which moves the ionization position point by point along the three-dimensional path of the target at a rate exceeding the persistence of vision of the human eye, and synthesizes a continuous three-dimensional light column pattern. The ultrasonic transducer unit and the beam emitting unit are packaged into multiple independent combined components. Each combined component is arranged in layers in the depth direction, with its working surface vertically upward. In a vertical plane perpendicular to the Z-axis, it performs up-down and left-right scanning by changing the beam direction. The physical position of each component on the Z-axis is fixed. The spatial continuous arrangement of the light spot trajectories generated by each component in the XY plane, and the superposition of each cross-section, forms a three-dimensional image. The effective imaging area of ​​the device is a spatial range of not less than 5 cm from the top of the shell. A sound field isolation structure is set between adjacent transducer units. The sound field isolation structure is configured to prevent mutual interference between the sound field focal points of adjacent transducer units through physical isolation, anti-phase sound wave cancellation or other equivalent methods.

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