Multifocal Augmented Reality Head-Up Display System and Method

Abstract

This invention provides a multi-focus head-up display system and method for solving the visual fatigue problem that occurs with automotive head-up displays and for realizing augmented reality functionality. [Solution] A multi-focus augmented reality head-up display system including: an image projector that generates and emits multiple beams; an optical device that guides the multiple beams emitted from the image projector to their respective paths; a polarization adjustment device that adjusts the polarization state of the multiple beams incident from the optical device; and multiple HOEs (Holographic Optical Elements) that each receive the multiple beams emitted from the polarization adjustment device and project virtual image planes at different focal lengths.

Description

Technical Field

[0001] The present invention relates to an automotive head-up display (HUD) system and method, and more particularly, to a multi-focal head-up display (MHUD) system and method for solving the visual fatigue problem occurring in an automotive head-up display and realizing an augmented reality (AR) function.

Background Art

[0002] A head-up display (hereinafter referred to as "HUD") is a device designed to allow a driver to check information necessary for vehicle operation while gazing ahead. Different from an existing instrument panel, it projects and displays information on a front windshield or a separate reflector. HUD technology contributes to improving safety and efficiency by minimizing visual field movement during driving, and is widely used particularly for providing information such as speed, navigation, and road conditions.

[0003] Recently, with the development of the automotive industry, augmented reality (AR) technology has been integrated into HUDs, exceeding the limitations of existing HUDs and providing a more intuitive and safe driving experience for drivers. This can enhance the accuracy and efficiency of information transmission by combining digital information with the actual road environment in real time beyond mere information transmission. For example, by utilizing augmented reality technology, a navigation route can be directly displayed on the road, or pedestrians and dangerous sections can be highlighted to strengthen a driver's concentration and safety.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

[0005] However, despite technological advancements, existing HUD systems still had several problems.

[0006] Firstly, existing HUD systems can cause visual fatigue. Because existing HUD systems display all information at a single focal length, drivers must repeatedly adjust their focus between the actual road and the HUD information. This results in accommodation-vergence conflict, a mismatch between the eye's accommodation and vergence. This induces visual fatigue in drivers and exacerbates inconvenience during long drives. Augmented reality-based HUDs, in particular, display virtual objects on the road, which can make the difference in focus between the actual road and the HUD even more noticeable.

[0007] Secondly, existing HUD systems may have issues with information visibility and analysis. In existing HUD systems, when all information is projected onto a single focal length, important and incidental information may overlap or become mixed. This can prevent drivers from quickly grasping necessary information, potentially increasing the risk of accidents. Furthermore, in daylight or bright environments, the projected information on the HUD may be difficult to see.

[0008] Third, existing HUD systems may have limitations in realizing augmented reality. For augmented reality technology to be effectively implemented in a HUD, virtual objects must be displayed accurately, matching the actual distance of the road and environment. However, existing HUD systems only support a single focal length, which limits their ability to intuitively recognize when virtual objects appear to be at inconsistent with their actual distance. Such problems can reduce the accuracy and reliability of augmented reality-based navigation route display or hazard highlighting functions.

[0009] Therefore, the present invention can be proposed to solve the aforementioned conventional problems.

[0010] The first problem (objective) to be solved in the present invention is to provide a multifocal augmented reality head-up display system and method that enables drivers to naturally perceive information between the road and HUD information without having to shift their focus, as multifocal distance support is essential to solve the visual fatigue problem that occurs in existing HUD systems.

[0011] Furthermore, a second problem that the present invention aims to solve is to provide a multi-focus augmented reality head-up display system and method that can effectively integrate augmented reality technology into a HUD to display information that matches the actual road environment, thereby facilitating the driver's intuitive understanding, improving driving stability, and providing the driver with an optimal driving experience.

[0012] Furthermore, a third problem that this invention aims to solve is to simplify the design of complex and bulky multi-plane HUDs (HUDs). Multi-plane HUDs require complex optical and mechanical designs to separate and display information on multiple planes, and the use of various optical components (lenses, reflectors, etc.) increases the size and weight of the system. Therefore, the present invention aims to provide a multi-focus augmented reality head-up display system and method that can simplify the design of a multi-plane HUD, reduce its volume and weight, and simplify its structure.

[0013] The problems to be solved by the present invention are not limited to those described above, and various other problems can be further provided through the techniques described in the embodiments below. [Means for solving the problem]

[0014] The present invention, relating to an embodiment for achieving the above objective, provides a multi-focus augmented reality head-up display system including: an image projector that generates and emits multiple beams; an optical device that guides the multiple beams emitted from the image projector to their respective paths; a polarization adjustment device that adjusts the polarization state of the multiple beams incident from the optical device; and multiple HOEs (Holographic Optical Elements) that receive the multiple beams emitted from the polarization adjustment device and project virtual image planes at different focal lengths.

[0015] The optical device may further include a diffuser that equalizes the energy and intensity of multiple beams incident from the optical device and transmits them to the polarization adjustment device.

[0016] Furthermore, the polarization adjustment device may control the polarization direction of each of the plurality of beams induced from the optical device, so that the polarization state of each of the plurality of beams matches the polarization state designed for each of the plurality of HOEs.

[0017] Furthermore, the optical device may be a MEMS (Micro Electro Mechanical Systems) mirror.

[0018] Furthermore, the plurality of beams may include red beams and blue beams.

[0019] In addition, the plurality of HOEs may include a first HOE that receives the red beam emitted from the polarization adjustment device and projects a virtual image plane at a first focal length; and a second HOE that receives the blue beam emitted from the polarization adjustment device and projects a virtual image plane at a second focal length different from the first focal length.

[0020] Further, the polarization adjustment device may control the polarization directions of the red beam and the blue beam incident from the optical device to match the polarization states of the red beam and the blue beam with the polarization states designed for the first and second HOEs.

[0021] Also, the first focal length may be smaller than the second focal length.

[0022] Also, the first focal length may be 1 m and the second focal length may be 1.5 m.

[0023] Also, the red beam may be in the 650 nm wavelength band and the blue beam may be in the 450 nm wavelength band.

[0024] In addition, the present invention according to an embodiment for achieving the above object provides a multi-focus augmented reality head-up display method including a process of generating and emitting a plurality of beams through a video projector; a process of guiding the plurality of beams to respective paths through an optical device; a process of adjusting the polarization states of the plurality of beams through a polarization adjustment device; and a process of receiving the plurality of beams emitted from the polarization adjustment device through a plurality of HOEs (Holographic Optical Elements) and projecting a virtual image plane at different focal lengths from each other.

[0025] Furthermore, the method may further include a process of equalizing the energy and intensity of the plurality of beams incident from the optical device through a diffuser and transmitting them to the polarization adjustment device.

[0026] Furthermore, the process of adjusting the polarization state of multiple beams via the polarization adjustment device may involve controlling the polarization direction of each of the multiple beams induced from the optical device to match the polarization state of each of the multiple beams with the polarization state designed for each of the multiple HOEs.

[0027] Furthermore, the plurality of HOEs may include a first HOE that receives a red beam emitted from the polarization adjustment device and projects a virtual image plane at a first focal length; and a second HOE that receives a blue beam emitted from the polarization adjustment device and projects a virtual image plane at a second focal length different from the first focal length.

[0028] Furthermore, the first focal length may be smaller than the second focal length.

[0029] Furthermore, the first focal length may be 1m, and the second focal length may be 1.5m.

[0030] Furthermore, the red beam may be in the 650 nm wavelength range, and the blue beam may be in the 450 nm wavelength range. [Effects of the Invention]

[0031] As described above, the embodiments of the present invention can provide the following effects.

[0032] Firstly, it is possible to provide 2D images with variable focus and multiple depth adjustments through a single optical system. This solves the single-focus problem of existing HUD systems, allowing drivers to obtain more intuitive information at various depths. In particular, the combination of a MEMS (Micro Electro Mechanical Systems) mirror and an HOE (Holographic Optical Element) enables the transmission of information at specific distances, reducing visual fatigue and significantly improving driving safety.

[0033] Secondly, by utilizing a single-image projector and a polarization adjustment device (polarization conversion display), information needed by the driver can be provided in a more dynamic manner through binocular parallax. In other words, by transmitting different images to the left and right eyes through polarization conversion technology using a polarization adjustment device, a higher level of immersion and accurate information provision is possible. This can make the realization of augmented reality functions even more realistic and improve the driver's experience.

[0034] Thirdly, the development of autonomous vehicles will create a foundation for actively utilizing the windshield as a HUD screen. Increased utilization of in-vehicle screens will enable the provision of a multi-depth HUD that can adjust focus according to various situations while driving. This will greatly help drivers to grasp the situation in real time during autonomous driving and selectively provide only the necessary information, ultimately potentially becoming the new HUD standard for the autonomous driving era. [Brief explanation of the drawing]

[0035] [Figure 1] This is a conceptual diagram showing a multi-focus augmented reality head-up display system according to an embodiment of the present invention. [Figure 2] Figure 1 is a diagram showing the configuration of the system. [Figure 3] This is a flowchart illustrating a multi-focus augmented reality head-up display method according to an embodiment of the present invention. [Figure 4] This is a diagram showing a configuration of an HOE (Holographic Optical Element) recording system according to an example of the present invention. [Modes for carrying out the invention]

[0036] The advantages and features of the present invention, and methods for achieving them, will become clearer with reference to the embodiments described below in detail with the accompanying drawings. Throughout this specification, the same reference numerals refer to the same components. Also, when "A and / or B" is written, it may mean both A and B, or either A or B. Furthermore, the size and shape of each component shown in the drawings may be exaggerated, but this is for illustrative purposes only and not intended to be limiting.

[0037] In the provisions described herein, singular forms include plural forms unless otherwise specified. Furthermore, components and actions referred to as "including (or comprising)" do not preclude the presence or addition of one or more other components and actions. Unless otherwise defined, all terms used herein (including technical and scientific terms) should be used in a sense commonly understood by a person of ordinary skill in the art to which the invention pertains. Furthermore, terms defined in commonly used dictionaries should not be idealized or over-analyzed unless otherwise defined.

[0038] The embodiments of the present invention will be described in detail below with reference to the attached drawings.

[0039] Figure 1 is a schematic conceptual diagram showing a multi-focus augmented reality head-up display system according to an embodiment of the present invention, and Figure 2 is a configuration diagram of the system shown in Figure 1.

[0040] Referring to Figures 1 and 2, the system according to an embodiment of the present invention combines a single projector generating unit (PGU), which is a video projector 10, with first and second holographic optical elements (HOEs, 20 and 30) to generate at least two or more virtual images 70 on a plane by utilizing the spectrum and angular selectivity of light.

[0041] The image projector 10 can emit light of a specific wavelength for interaction with a plurality of holographic light source elements, for example, first and second holographic light source elements 20, 30 (hereinafter referred to as "first and second HOEs"). Such an image projector 10 includes a light source internally, which may be, for example, an LED (Light Emitting Diode), a laser, or other suitable optical light-emitting element. For example, a laser diode (LD) having characteristics such as high power output and high energy efficiency, narrow bandwidth, high optical focusing, miniaturization and weight reduction, and long lifespan may be used as an example.

[0042] The video projector 10 includes a red laser source (11) and a blue laser source (12), as shown in Figure 2. The red laser source 11 is a light source that generates high-power red light with a narrow bandwidth and provides an optical basis for generating independent virtual images. That is, the red light is projected onto a specific focal plane via a first HOE 20 and used to realize one of the projected virtual image planes. The blue laser source 12 is a light source that generates high-power blue light with a narrow bandwidth and uses a different wavelength band than the red light, generating a virtual image on an independent focal plane through interaction with a second HOE 30.

[0043] As shown in Figure 1, the red light (hereinafter referred to as the "red beam") and blue light (hereinafter referred to as the "blue beam") emitted from the red light source 11 and blue light source 12 of the image projector 10 are incident on the optical device 40, respectively. The optical device 40 dynamically controls the direction, angle, or position of the incident red and blue beams to accurately guide them to the first and second HOEs 20 and 30. Such an optical device 40 may be, for example, a MEMS (Micro Electro Mechanical Systems) mirror.

[0044] The MEMS mirror may include a mirror, a drive unit, a suspension, and a control circuit. The mirror reflects a laser beam onto a reflective surface of a silicon wafer substrate. The drive unit drives the mirror using electrostatic, electromagnetic, thermal, or piezoelectric methods. The suspension supports the surface of the mirror and allows it to rotate or move. For example, it may be designed to rotate at high speed using a torsional hinge. The control circuit controls the movement of the mirror and adjusts its angle and position based on input signals.

[0045] As shown in Figure 1, the red and blue beams reflected by the optical device 40 are transmitted to the diffuser (diffuser, 50). The diffuser 50 can perform beam homogenization, wide-angle diffusion, and speckle reduction on the red and blue beams reflected from the optical device 40. In other words, it provides optical uniformity, supports multiple focal planes, and expands the field of view within the system.

[0046] The beam reflected by the optical device 40 is highly focused, and the beam's energy may be concentrated at the center. Therefore, the diffuser 50 distributes the beam's energy and intensity uniformly, resulting in uniform image brightness and quality, thus evenly dispersing the high-intensity point source of the beam over a wide area. Furthermore, because the beam is highly directional (narrow divergence), it can be dispersed at various angles to cover a wide area in the image plane. In particular, when forming multiple planes, for example, independent focal planes for red and blue, the beam can be diffused at appropriate angles to extend the focal area. In addition, because the beam is highly coherent and can produce irregular brightness patterns called speckles, randomizing the beam's direction and phase can reduce the speckle pattern and produce a softer, sharper image.

[0047] In this way, the diffuser 50 can disperse the red beam reflected by the optical device 40 and appropriately extend it to reach the focal plane of the first HOE 20, and disperse the blue beam in the same manner as the red beam and appropriately disperse it to the focal plane of the second HOE 30 to form other depth information. That is, the red beam and blue beam reflected by the optical device 40 reach the other focal planes uniformly via the diffuser 50, thereby generating a complex multilayer image.

[0048] As shown in Figure 1, the beam diffused through the diffuser 50 is transmitted to the polarization adjustment device 60. The polarization adjustment device 60 is a polarization switchable display that dynamically adjusts the polarization state of the red and blue beams transmitted from the diffuser 50.

[0049] The polarization adjustment device 60 is a device that controls the polarization direction (vertical, horizontal, circular, etc.) of the red beam and blue beam transmitted from the diffuser 50, and can change the polarization state of the beam to maximize the photoprocessing efficiency of other optical elements, namely the first and second HOEs 20 and 30. For example, the red beam can be converted to vertical polarization, and the blue beam can be converted to horizontal polarization. Thereafter, the first and second HOEs 20 and 30 can selectively process the beam based on each polarization state.

[0050] HOE elements are designed to efficiently interact with light in a specific polarization state. Multiple such HOE elements may be installed. If the polarization states of the incident red and blue beams do not match (align) the polarization states of the first and second HOEs 20 and 30, the beam reflection, refraction, or diffraction efficiency may decrease. Therefore, the polarization adjustment device 60 matches the polarization states of the red and blue beams incident from the diffuser 50 with the optimized polarization states designed for the first and second HOEs 20 and 30 (converting the polarization states of the red and blue beams to match the polarization states of the first and second HOEs 20 and 30).

[0051] The polarization adjustment device 60 independently adjusts the red and blue beams to generate information at different depths, thereby realizing a multifocal plane. As a result, the red and blue beams, whose polarization states are adjusted via the polarization adjustment device 60, pass through the first and second HOEs 20 and 30, generating independent images in each focal plane. Therefore, multi-layer images can be realized in the augmented reality display. Furthermore, in automotive environments, incoming light (e.g., sunlight, headlights) can be bright and reduce visibility. Therefore, the polarization adjustment device 60 can adjust the polarization state of the external light entering the display, thereby reducing interference from the external light and preventing it from affecting the display's performance.

[0052] Such a polarization adjustment device 60 provides the ability to transmit different images to the left and right eyes even with a single display panel. It operates by rapidly switching the polarization state to transmit the intended light to each eye. This principle can be realized by projecting the image generated by the display panel differently depending on the polarization state of the light. By rapidly switching the polarization state, the panel can send light of a specific polarization state to the left and right eyes, respectively, using only a single display panel, thereby transmitting different images to each.

[0053] The first HOE20 receives a red beam, adjusted by the polarization state adjustment device 60, as input. The red beam has a controlled directionality and a specific wavelength, optimized for the wavelength and angle selectivity of the first HOE20. The first HOE20 uses the red beam to project a virtual image plane at a short focal length (hereinafter referred to as the "first focal length"), for example, at a distance of 1 m. The first HOE20 is optimized to diffract and refract the image according to the specific wavelength (e.g., 650 nm) and incident angle of the red beam. This allows the red beam to form a clear and accurate virtual image at close range.

[0054] The first HOE20 does not selectively respond to light of different wavelengths or angles. This spectral and angular selectivity ensures that it processes only red beams to generate an accurate virtual image. Through this, interference from external light sources or light of different hues can be minimized. The virtual image generated by the first HOE20 is transmitted to the user's (driver's) eyes. The user will see a clear red image at a distance of 1 meter, which may be suitable for near-field information on augmented reality displays (e.g., instrument panel data, road condition displays, etc.).

[0055] The second HOE30 receives a blue beam as input, which has been adjusted by the polarization state adjustment device 60. Unlike the red beam, the blue beam has an even shorter wavelength (e.g., 450 nm) and is adjusted to match the wavelength and angular selectivity of the second HOE30. The second HOE30 uses the blue beam to project a virtual image plane at a far-field focal length (hereinafter referred to as the "second focal length") greater than the first focal length (for example, at a distance of 1.5 m). Through this, a virtual image can be formed at the far-field focal length. This may be suitable for displaying far-field information to the user (e.g., navigation arrows, road signs, etc.).

[0056] The second HOE30 selectively processes only light of a specific wavelength and angle to generate a virtual image. This prevents mutual interference with the first HOE20 and ensures that each HOE can operate independently. The virtual image generated by the second HOE30 is transmitted to the user through diffracted and refracted light, allowing the user to see a clear blue image at a distance of 1.5m. This may be suitable for long-range information display (e.g., road directions, warning messages, etc.).

[0057] Figure 3 is a flowchart illustrating a multi-focus augmented reality head-up display method according to an embodiment of the present invention.

[0058] Referring to Figures 2 and 3, the multifocal augmented reality head-up display method using the multifocal augmented reality head-up display system according to an embodiment of the present invention is as follows.

[0059] Input red and blue beams respectively (S1, S1'). Video project The ejector 10 generates a red beam and a blue beam via a red light source 11 and a blue light source 12, and emits them into the optical device 40.

[0060] Next, the red and blue beams are dynamically guided to their respective paths (S2). The optical device 40 dynamically controls the direction, angle, or position of the red and blue beams emitted from the image projector 10 to precisely guide them to their respective paths, i.e., the first and second HOEs 20 and 30.

[0061] Next, the directional laser beam is scattered to generate a uniform intensity distribution (S3). The diffuser 50 performs uniformity, wide-angle diffusion, and speckle removal on the red and blue beams incident through the optical device 40, thereby distributing the beam's energy and intensity uniformly and outputting it.

[0062] Next, the polarization state of the laser beam is modulated to align it favorably with the HOE (S4). The polarization adjustment device 60 controls the polarization direction (vertical, horizontal, circular, etc.) of the red and blue beams transmitted from the diffuser 50 to match the polarization state of the red and blue beams incident from the diffuser 50 with the polarization state designed for the first and second HOEs 20 and 30.

[0063] Next, the red beam is received and an image plane is projected at a first focal length (short distance, 1 m), and the blue beam is received and an image plane is projected at a second focal length (long distance, 1.5 m) (S5, S5'). The first HOE20 uses the red beam incident from the polarization adjustment device 60 to focus on the virtual image plane at the first focal length (1 m), and the second HOE30 uses the blue beam to focus on and project the virtual image plane at the second focal length (1.5 m).

[0064] Next, the image planes projected onto virtual image planes with a first focal length (1m) and a second focal length (1.5m) are combined for the driver to provide a multifocal augmented reality experience (S6).

[0065] Figure 4 is a schematic diagram showing an example of an HOE recording system according to the present invention.

[0066] Referring to Figure 4, an example of the present invention is an HOE recording system for recording optical information and fabricating an HOE element having specific optical properties, which can be used to fabricate first and second HOEs 20 and 30. The configuration may include a laser source (81), an electronic shutter (82), a spatial filter (83), a beam splitter (84), a beam expander (85), a collimating lens (86), a motorized linear stage (MLS, 87), a precision linear translation stage (PLTS, 88), photodetectors (89), and a holographic recording medium (90).

[0067] The laser light source 81 provides a light source for HOE recording. It uses a monochromatic laser with high coherence, such as a red laser (650 nm), a green laser (532 nm), or a blue laser (450 nm).

[0068] The electronic shutter 82 controls the exposure time of the laser beam for accurate recording of the HOE.

[0069] The spatial filter 83 removes noise from the laser beam, ensuring a high-quality Gaussian beam. Such a spatial filter 83 may consist, for example, of a fine pinhole and a lens.

[0070] The beam splitter 84 is a polarizing beam splitter (PBS) that separates the incident beam into two different paths based on its polarization state. That is, it separates the laser beam into two paths. Such a beam splitter 84 separates the beam into, for example, a reference beam path (parallel light transmitted to the HOE) and an object beam path (light modified to produce a desired interference pattern). The beams separated by the beam splitter 84 are guided to specific paths via mirrors M1 and M2.

[0071] The beam expander 85 is used to broaden the beam incident through the reflectors M1 and M2 to adjust the size of the interference pattern, and further expands the laser beam for uniform exposure over a wider area. In other words, it expands the diameter of the laser beam to uniformly expose the entire recording medium.

[0072] The parallel lens 86 precisely converts the beam expanded by the beam expander 85, which may contain slight converging or diverging components, into a parallel beam, thereby improving the accuracy of the interference fringes. Through this, the beam direction can be kept constant and precisely directed to the desired position on the recording medium, improving the spatial accuracy and recording quality of the HOE.

[0073] The motor-driven linear stage 87 precisely moves the positions of the beam expander 85 and the parallel lens 86 to precisely move the position of the laser beam, and is used to adjust the position of the medium or dynamically change the path that forms the interference pattern during the HOE recording process, and moves the collimating lens with micrometer precision and adjusts the distance between the lens and the holographic recording medium 90 to correct the focal length of the recorded HOE.

[0074] The precision linear movement stage 88 moves the holographic recording medium 90 vertically or horizontally to record multiple HOEs on a single recording medium. Multiple HOEs are recorded at different positions using the holographic recording medium 90 mounted on the precision linear movement stage 88.

[0075] The photodetector 49 monitors the intensity and quality of the laser beam in real time, measuring the intensities of the reference beam and the object beam to ensure that the interference pattern is uniformly formed. Such a photodetector 49 may include a diffraction beam detector that measures the intensity of the diffracted beam to monitor recording efficiency and a transmission beam detector that measures the intensity of the transmitted beam to monitor the beam alignment.

[0076] The holographic recording medium 90 records interference patterns via the input beam, and the final HOE element is fabricated.

[0077] As described above, in the system according to the embodiment of the present invention, a technique for projecting a virtual image plane using red and blue beams in different wavelength bands has been described as an example. However, this is for the convenience of explanation, and the system may be configured to project a virtual image plane using at least one beam from the red and blue beams and / or at least two beams from other beams. For example, the image projector 10 can generate and emit at least two or more beams. In this case, the multiple beams may include at least one of the red and blue beams, or beams in other wavelength bands excluding these. The optical device 40 guides the multiple beams emitted from the image projector 10 to their respective paths, the diffuser 50 transmits the multiple beams incident on different paths in the optical device 40 to the polarization adjustment device 60, and the polarization adjustment device 60 adjusts the polarization state of the multiple beams transmitted from the diffuser 50 and transmits them to the multiple HOEs. The number of HOEs corresponds to the number of beams emitted from the polarization adjustment device 60, and a virtual image plane is projected onto each of the beams.

[0078] As described above, preferred embodiments of the present invention have been explained and illustrated using specific terminology, but such terminology is solely for the purpose of clearly explaining the present invention. It is obvious that the embodiments and described terminology of the present invention can be modified and altered in various ways without departing from the technical spirit and scope of the following claims. Such modified embodiments should not be understood separately from the spirit and scope of the present invention, but should be considered to fall within the scope of the claims of the present invention. [Explanation of Symbols]

[0079] 1...Dashboard, 2...User (Driver), 10...Video Projector, 11...Red Light Source, 12...Blue Light Source, 20...First HOE, 30...Second HOE, 40...Optical Device, 50...Diffuser, 60...Polarization Adjuster, 70...Virtual Image, 81...Laser Light Source, 82...Electronic Shutter, 83...Spatial Filter, 84...Beam Splitter, 85...Beam Expander, 86...Parallel Lens, 87...Motor-Driven Linear Stage, 88...Precision Linear Moving Stage, 89...Photodetector, 90...Holographic Recording Medium

Claims

1. A video projector that generates and emits multiple beams, An optical device that guides multiple beams emitted from the aforementioned video projector to their respective paths, A polarization adjustment device for adjusting the polarization state of multiple beams incident from the optical device, and Multiple HOEs (Holographic Optical Elements) receive multiple beams emitted from the polarization adjustment device and project virtual image planes at different focal lengths, A multi-focus augmented reality head-up display system, including a multi-focus augmented reality head-up display system.

2. The multifocal augmented reality head-up display system according to claim 1, further comprising a diffuser that equalizes the energy and intensity of a plurality of beams incident from the optical device and transmits them to the polarization adjustment device.

3. The multifocal augmented reality head-up display system according to claim 1 or 2, wherein the polarization adjustment device controls the polarization direction of each of the plurality of beams induced from the optical device to match the polarization state of each of the plurality of beams to the polarization state designed for each of the plurality of HOEs.

4. The multifocal augmented reality head-up display system according to claim 1 or 2, wherein the optical device is a MEMS (Micro Electro Mechanical Systems) mirror.

5. The multifocal augmented reality head-up display system according to claim 1 or 2, wherein the plurality of beams include a red beam and a blue beam.

6. The aforementioned multiple HOEs are, A first HOE that receives a red beam emitted from the polarization adjustment device and projects a virtual image plane at a first focal length, and A second HOE receives a blue beam emitted from the polarization adjustment device and projects a virtual image plane at a second focal length different from the first focal length, A multifocal augmented reality head-up display system according to claim 1 or 2, comprising:

7. The multifocal augmented reality head-up display system according to claim 6, wherein the polarization adjustment device controls the polarization direction of the red beam and blue beam incident from the optical device to match the polarization state of the red beam and blue beam to the polarization state designed for the first and second HOEs.

8. The multifocal augmented reality head-up display system according to claim 6, wherein the first focal length is smaller than the second focal length.

9. The multifocal augmented reality head-up display system according to claim 6, wherein the first focal length is 1 m and the second focal length is 1.5 m.

10. The multifocal augmented reality head-up display system according to claim 6, wherein the red beam is in the 650 nm wavelength band and the blue beam is in the 450 nm wavelength band.

11. The process of generating and emitting multiple beams via a video projector, The process of guiding the multiple beams to their respective paths via an optical device, A process of adjusting the polarization state of each of the plurality of beams via a polarization adjustment device, and The process involves receiving multiple beams emitted from the polarization adjustment device via multiple HOEs (Holographic Optical Elements) and projecting virtual image planes at different focal lengths, A multi-focus augmented reality head-up display method, including...

12. The multifocal augmented reality head-up display method according to claim 11, further comprising the step of equalizing the energy and intensity of the plurality of beams incident from the optical device via a diffuser and transmitting them to the polarization adjustment device.

13. The multifocal augmented reality head-up display method according to claim 11 or 12, wherein the process of adjusting the polarization state of a plurality of beams via the polarization adjustment device involves controlling the polarization direction of each of the plurality of beams induced from the optical device to match the polarization state of each of the plurality of beams with the polarization state designed for each of the plurality of HOEs.

14. The aforementioned multiple HOEs are, A first HOE that receives a red beam emitted from the polarization adjustment device and projects a virtual image plane at a first focal length, and A second HOE receives a blue beam emitted from the polarization adjustment device and projects a virtual image plane at a second focal length different from the first focal length, A multifocal augmented reality head-up display method according to claim 11 or 12, including the method described in claim 11 or 12.

15. The multifocal augmented reality head-up display method according to claim 14, wherein the first focal length is smaller than the second focal length.

16. The multifocal augmented reality head-up display method according to claim 14, wherein the first focal length is 1 m and the second focal length is 1.5 m.

17. The multifocal augmented reality head-up display method according to claim 14, wherein the red beam is in the 650 nm wavelength band and the blue beam is in the 450 nm wavelength band.

Images