Head wearable display system for increasing eyesight

Abstract

SOLUTION: To provide a head wearable display system having a detection module for receiving multiple image pixels of first and second parts of a target object and corresponding depths, a first light emitter for generating first multiple eye glitter signals so as to display a first eye virtual image of a target object to an observer, a first light direction changer for changing a light signal of first multiple eye glitter signals, a first collimater that is disposed between the first light emitter and the first light direction changer and adjusts a beam waist position of first multiple eye glitter signals so as to be separable mutually, a first converging element that is disposed between the first collimater and the first light direction changer and adjusts a spot size by adjusting a beam waist size, and a first combiner for changing a direction toward a first eye and performing convergence.EFFECT: A first eye virtual image of a first part of a target object in a first visual field has a larger number of first eye glitter signals per degree than a first eye virtual image of a second part of a target object in a second visual field.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a system that provides enhanced visual acuity, and more particularly to a head-wearable display system that may produce machine-assisted visual acuity greater than 1.0 with depth perception. [Background technology]

[0002] Visual ability is often limited by the anatomy of the human eye. In particular, parameters such as the refractive power of the eye's lens, the axial length of the eyeball, and the condition of the cornea and retina significantly affect visual ability. Until now, commercially available machine vision for achieving superior visual ability has not been available. In recent years, machine vision has been developed and adopted in many industrial fields to improve the visual acuity of people with visual impairments. In particular, machine vision has been applied in the medical field to assist patients with focusing disabilities and vision-impairing conditions such as glaucoma and myopic macular degeneration. For example, pixelated image augmentation can help restore a patient's vision by increasing the brightness and contrast of the objects the patient is viewing. However, this only partially restores the patient's vision. Summary of the Invention [Problem to be solved by the invention]

[0003] Therefore, there is a need to provide a head-wearable display device that is convenient for everyday use and has the potential to partially or substantially replace natural human vision by providing the user with visual acuity that exceeds normal human vision.

[0004] The objective of the present invention is to use a light-emitting device based on optical signal scanning in a head-wearable display system / device (e.g., AR glasses or VR goggles) or a retinal scanning device to help people with visual deficiencies or visual impairments return to normal life. In particular, the present invention can capture real-time image information of a target object or the observer's surrounding environment viewed by an observer, and reproduce a three-dimensional digital (or pixelated) image with depth perception for the observer. Furthermore, the present invention can provide vision correction for people with myopia or presbyopia, etc., as an alternative to traditional prescription glasses. The present invention can also improve vision beyond the normal visual capabilities of healthy people. [Means for solving the problem]

[0005] The head-wearable display system includes a target object detection module, a first light emitter, a first light redirector, a first collimator, a first focusing element, and a first combiner. The target object detection module is used to receive a plurality of image pixels of a first portion and a second portion of the target object and corresponding depths of the first portion and the second portion. The first light emitter is used to emit a plurality of first-eye light signals related to the target object to display a first-eye virtual image of the first portion and the second portion of the target object to a viewer. For example, the plurality of first-eye light signals may directly reproduce the image pixels of the target object so that a viewer can view the first-eye virtual image of the target object via the head-wearable display system. The first light emitter may be capable of generating light pulses to create a pixelated image. In some cases, the light emitter may include a red laser diode, a green laser diode, and a blue laser diode. The first light redirector receives the plurality of first ocular light signals emitted by the first light emitter and redirects the light direction of each of the plurality of first ocular light signals emitted from the first light emitter. The light direction may be changed in multiple spatial dimensions over time so that an image is created by the periodic scanning motion of the first light redirector, creating an image frame within a certain period of time. The light redirector referred to in this specification may refer to a mechanical or optical element that can dynamically change the direction of light emitted by the light emitter over time. The first collimator may be disposed between the first light emitter and the first light redirector to collimate the plurality of first ocular light signals from the first light emitter so as to adjust the beam waist position of each of the plurality of first ocular light signals so that the plurality of first ocular light signals are separable from one another. In another embodiment, the first collimator may be disposed between the first light redirector and the first combiner. Furthermore, the first collimator may change the optical path length of the first ocular light signals. The first focusing element is disposed between the first collimator and the first light redirector and adjusts the beam waist size of each of the plurality of first eye light signals to adjust the spot size of the plurality of first eye light signals at the first eye of the observer.Specifically, the first focusing element focuses the multiple first eye light signals from the first collimator to adjust the beam waist of each of the multiple first eye light signals, thereby adjusting the beam waist of the multiple first eye light signals emitted by the first light redirector.

[0006] The first combiner is used to redirect and focus the multiple first eye light signals toward the first eye of the observer. In some embodiments, the first combiner receives the multiple first eye light signals from the first light redirector and converges and directs the multiple first eye light signals toward the first eye of the observer. The first light redirector may rotate within a certain angle range or move within a certain linear displacement range. The light directions of the multiple first eye light signals may also be changed within a specific range, and when the first combiner receives the multiple first eye light signals from the first light redirector, the first combiner directs each first eye light signal having a different angle of incidence toward the first eye of the observer. The multiple first eye light signals are directed toward the first eye of the observer within a predetermined angle of incidence, which corresponds to the maximum field of view (FOV) generated by the head-wearable display system. In some embodiments, the spot size of the first eye light signal projected onto the retina of the first eye can be manipulated by changing the distance between the light redirector and the first collimator.

[0007] In one embodiment, the first focusing element has a radius of curvature between -5 mm and -50 mm.

[0008] In one embodiment, the plurality of first optical light signals emitted by the first light redirector are emitted to the first combiner at a first optical light incidence angle between 15 degrees and 75 degrees.

[0009] In one embodiment, the head-wearable display system further comprises a first light redirector for receiving a plurality of first eye light signals and changing the light direction of each of the plurality of first eye light signals; and a second light redirector disposed adjacent to a first focal point of the first light redirector and the first focal point of the first combiner, the second light redirector being a reflector, wherein the first light redirector receives the plurality of first eye light signals and directs the plurality of first eye light signals to the first combiner, which directs the plurality of first eye light signals received from the first light redirector to a first eye of an observer so that the observer sees a first image frame constituted by the plurality of first eye light signals; and the first light redirector changes the projection direction of the plurality of first eye light signals in a first dimension between a first spatial dimension limit and a second spatial dimension limit. The geometric shape of the first light redirector is configured to substantially equalize the total optical path length from the first light redirector to the first eye of the observer in one of the plurality of first eye light signals emitted by the first light redirector near the first spatial dimension limit to the total optical path length from the first light redirector to the first eye of the observer in another of the plurality of first eye light signals emitted by the first light redirector near the second spatial dimension limit, the first light redirector has two foci located within the space between the first light redirector and the first eye of the observer, the first focus of the first light redirector and the first focus of the first combiner are at the same spatial position, the first light redirector is adjacent to the second focus of the first light redirector, and the shortest distance from the first combiner to the first eye of the observer is 15 mm to 30 mm.

[0010] In one embodiment, the plurality of first optical light signals emitted by the first light redirector are emitted to the first light redirector at a first optical light incidence angle, the first optical light incidence angle being between 15 degrees and 75 degrees.

[0011] In one embodiment, the head-wearable display system includes a second light emitter that emits a plurality of second eye light signals corresponding to the plurality of first eye light signals to display a second-eye virtual image of a first portion and a second portion of a target object to an observer, a second light direction changer that changes the light direction of each of the plurality of second eye light signals emitted from the second light emitter, and a second collimator that is disposed between the second light emitter and the second light direction changer and adjusts a beam waist position of each of the plurality of second eye light signals so that the plurality of second eye light signals can be separated from each other. The optical system further comprises a second collimator, a second focusing element positioned between the second collimator and the second light redirector, adjusting the beam waist size of each of the plurality of second eye light signals to adjust the spot size of the plurality of second eye light signals at the second eye of the observer, and a second combiner redirecting and converging the plurality of second eye light signals toward the second eye of the observer, wherein the second-eye virtual image of the first portion of the target object in the third FOV includes a greater amount of the plurality of second eye light signals per degree compared to the second-eye virtual image of the second portion of the target object in the fourth FOV.

[0012] In one embodiment, the second focusing element has a radius of curvature between -5 mm and -50 mm.

[0013] In one embodiment, the plurality of second eye light signals emitted by the second light redirector are emitted to the second combiner at a second eye light incidence angle between 15 degrees and 75 degrees.

[0014] In one embodiment, the head-wearable display system further comprises a third light redirector for receiving a plurality of second eye light signals and changing a light direction of each of the plurality of second eye light signals; and a fourth light redirector disposed adjacent a first focal point of the third light redirector and a first focal point of the second combiner, the fourth light redirector being a reflector, wherein the third light redirector receives the plurality of second eye light signals and directs the plurality of second eye light signals to the second combiner, which directs the plurality of second eye light signals received from the third light redirector to a second eye of an observer so that a second image frame constituted by the plurality of second eye light signals is viewed by the observer; and the second light redirector changes a projection direction of the plurality of second eye light signals in a second dimension between the third spatial dimension limit and the fourth spatial dimension limit. The geometric shape of the third light redirector is configured to substantially equalize the total optical path length from the second light redirector to the observer's second eye in one of the plurality of second eye light signals emitted by the second light redirector near the third spatial dimension limit to the total optical path length from the second light redirector to the observer's second eye in another of the plurality of second eye light signals emitted by the second light redirector near the fourth spatial dimension limit, the third light redirector has two foci located within the space between the third light redirector and the observer's second eye, the first focus of the third light redirector and the first focus of the second combiner are at the same spatial position, the second light redirector is adjacent to the second focus of the third light redirector, and the shortest distance from the second combiner to the observer's second eye is 15 mm to 30 mm.

[0015] In one embodiment, the plurality of second eye light signals emitted by the second light redirector are emitted to the third light redirector at a second eye light incidence angle that is between 15 degrees and 75 degrees.

[0016] The present invention can capture real-time image pixels of a target object or surrounding environment and reproduce a three-dimensional digital image with enhanced image quality for the observer of the AR / VR system. The observer of the present invention can adjust the image quality to achieve better-than-normal visual acuity (e.g., better than 20 / 20 vision or VA 1.0). Furthermore, the present invention may provide vision correction for people with myopia, hyperopia, etc., to help people with visual impairments or as an alternative to traditional prescription glasses. The present invention can be used by medical professionals, military personnel, precision manufacturing industries, aerospace pilots, law enforcement, emergency rescue personnel, athletes, etc. [Brief explanation of the drawings]

[0017] [Figure 1] Figure 1 is a schematic diagram of the Rayleigh criterion.

[0018] [Figure 2] FIG. 2 is a schematic diagram illustrating the variation of spot size at different projection planes.

[0019] [Figure 3] FIG. 3 is a schematic diagram of a display system according to the present invention.

[0020] [Figure 4A] FIG. 4A is a schematic diagram illustrating the effect of changing the position of the collimator.

[0021] [Figure 4B] FIG. 4B is another schematic diagram illustrating the effect of changing the position of the collimator.

[0022] [Figure 5A] FIG. 5A is a schematic diagram illustrating the effect of varying the duration of light emission on the spot size.

[0023] [Figure 5B] FIG. 5B is another schematic diagram illustrating the effect of varying the duration of light emission on the spot size.

[0024] [Figure 6] FIG. 6 is a schematic diagram illustrating the effect on the FOV of changing the spatial separation between adjacent optical signals.

[0025] [Figure 7A] FIG. 7A is a schematic diagram illustrating one embodiment for varying the spatial separation between adjacent optical signals.

[0026] [Figure 7B] FIG. 7B is another schematic diagram illustrating an embodiment for varying the spatial separation between adjacent optical signals.

[0027] [Figure 7C] FIG. 7C is another schematic diagram illustrating an embodiment for varying the spatial separation between adjacent optical signals.

[0028] [Figure 8] FIG. 8 is a schematic diagram illustrating one embodiment of changing the swing frequency of a light redirector to change visual acuity.

[0029] [Figure 9] FIG. 9 is a schematic diagram of a display system according to another embodiment of the present invention.

[0030] [Figure 10] FIG. 10 is another schematic diagram of a display system according to another embodiment of the present invention.

[0031] [Figure 11] FIG. 11 is another schematic diagram of a display system according to another embodiment of the present invention.

[0032] [Figure 12] FIG. 12 is another schematic diagram of a display system according to another embodiment of the present invention.

[0033] [Figure 13] FIG. 13 is a schematic diagram of an embodiment of an optical assembly according to the present invention.

[0034] [Figure 14] FIG. 14 is another schematic diagram of an embodiment of an optical assembly according to the present invention.

[0035] [Figure 15] FIG. 15 is a schematic diagram for explaining the application of the present invention.

[0036] [Figure 16] FIG. 16 is a schematic diagram illustrating yet another embodiment of a head-wearable display system according to the present invention.

[0037] [Figure 17] FIG. 17 is a schematic diagram illustrating the effect of a focusing element on an optical signal.

[0038] [Figure 18A] FIG. 18A is a schematic diagram (part 1) illustrating the effect of changing the radius of curvature of the focusing element on the spot size. [Figure 18B] FIG. 18B is a second schematic diagram illustrating the effect of changing the radius of curvature of the focusing element on the spot size. [Figure 18C] FIG. 18C is a schematic diagram (part 3) illustrating the effect of changing the radius of curvature of the focusing element on the spot size.

[0039] [Figure 19A] FIG. 19A is a schematic diagram (part 1) illustrating the effect of a change in the incident angle on the spot size. [Figure 19B] FIG. 19B is a schematic diagram (part 2) illustrating the effect of a change in the incident angle on the spot size. [Figure 19C] FIG. 19C is a schematic diagram (part 3) illustrating the effect of a change in the incident angle on the spot size.

[0040] [Figure 20] FIG. 20 is a schematic diagram illustrating an embodiment of the present invention.

[0041] [Figure 21] FIG. 21 is another schematic diagram illustrating an embodiment of the present invention.

[0042] [Figure 22] FIG. 22 is a schematic diagram illustrating yet another embodiment of a head-wearable display system according to the present invention.

[0043] [Figure 23A] FIG. 23A is a diagram illustrating the quality of an image frame in the prior art.

[0044] [Figure 23B] FIG. 23B is a diagram illustrating the quality of an image frame according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0045] The terms used in the following description are intended to be interpreted in their broadest reasonable terms, even when used in conjunction with detailed descriptions of specific embodiments of the technology. Certain terms may be emphasized below, but terms that are intended to be interpreted in a restrictive manner are specifically defined in this detailed description.

[0046] One aspect of the present invention aims to enhance human vision beyond the normal visual capabilities (monitoring) of healthy people. In another aspect, the present invention provides improved vision to people with visual impairments such as myopia or astigmatism, or helps train visually impaired eyes to improve vision. In yet another aspect, the present invention can essentially replace the vision of people with focusing disabilities or other severe visual impairments. The present invention may function as an assistive device to improve the human vision of an observer, and in some cases, the present invention may partially or nearly completely replace the function of the human eye for people with eye impairments. Furthermore, for visually impaired observers, the systems and methods of the present invention can provide a clear image to a healthy portion of the observer's retina, bypassing damaged or impaired eye tissue. The present invention takes into account the axial length of the observer's eyeball and the condition of the cornea and retina and incorporates them into the design of the present invention. In addition, the present invention can provide multiple or continuous depth perception to allow the observer to perceive the highest degree of realism. The present invention can receive multiple image pixels of a distant target object and reproduce a virtual image of the target object to the observer with greater visual acuity.

[0047] The term "visual acuity" relates to the number of critical gaps that can be distinguished by an observer within one arc minute of the field of view (FOV). A common definition of visual acuity (VA) is given by the following formula: Visual acuity = 1 / gap size (arc minutes); and 1 arc minute = 1 / 60 degree.

[0048] A VA of 1.0 (or 20 / 20) requires that the observer's eye be able to distinguish contrast patterns (e.g., black and white patterns) within 1 arcminute of the FOV. In other words, a VA of 1.0 requires that the observer's eye be able to distinguish 60 contrast patterns within 1 degree of the FOV. For example, if a person can only distinguish contrast patterns within 2 arcminutes of the FOV, the VA is 0.5. The VA described in this invention relates to the number of pixels that are distinguishable / separable to the retina within 1 arcminute, which is 1 / 60 degree of the FOV. In other words, to achieve a VA better than the normal VA (VA of 1.0) in a pixelated display system, the goal is to project an image of at least a portion of a target object to the observer with an increased number of retinal distinguishable pixels per degree of FOV, or to project an image of a target object with more than 60 distinguishable light signals / pixels per degree of FOV, which includes at least a portion of a virtual image of the target object. Alternatively, in some examples of the present application, the goal is to project an image of a target object with more than 120 (VA2.0) or 180 (VA3.0) distinguishable light signals / pixels at the retina per degree of FOV that includes at least a portion of the virtual image of the target object. In other words, to achieve the highest possible VA, it is necessary to project as many distinguishable / separable pixels as possible onto the retina of the observer's eye. The spatial separation between two adjacent pixels determines whether those pixels are distinguishable on the retina. The spatial separation between two adjacent pixels on the retina (or other part of the observer's eye) must meet a set of criteria related to VA. Additionally, to project a greater number of retina-distinguishable pixels within one arcminute of the FOV, the cross-sectional area of ​​the pixel must be reduced to allow for more pixels to be included within one arcminute of the FOV.

[0049] Referring to FIG. 1 , regardless of the distance or size of the target object intended to be reproduced to the observer by the present invention, the reproduced image of the target object must be distinguishable on the observer's retina. More specifically, the optical signal (light pulse signal or light beam signal) that generates the image must satisfy the Rayleigh criterion, which is known as the specification for the minimum separation between two optical signals that can be resolved as distinguishable / separable. In a pixelated display system, the optical signals correspond to the pixels that generate the virtual image. For example, each optical signal may contain a pixel of the image of the target object. Also, each optical signal may have an approximately circular or elliptical cross-sectional area (also known as the "spot size") when projected onto the cross-sectional plane of the optical path (e.g., the retina of the observer's eye). According to the Rayleigh criterion, for two optical signals to be distinguishable, the spatial distance / separation between the centers of two adjacent optical signals must be greater than half the maximum diameter of the adjacent optical signals (approximately half the spot size). Based on the above reasons, while it is feasible to increase the number of optical signals per FOV unit (e.g., per degree) to increase VA, to make two adjacent optical signals distinguishable / separable, the separation between the two adjacent optical signals must be maintained to satisfy the Rayleigh criterion. For this reason, increasing the observer's VA cannot be achieved simply by increasing the resolution (which may result in a smaller separation between the two adjacent optical signals). While changing the spot size of the optical signals, it is also very important to maintain a sufficient spatial distance / separation between the centers of the two adjacent optical signals. If the spatial distance / separation between the centers of the two adjacent optical signals is too large, the image quality (i.e., resolution) may be degraded. Clearly, to increase VA above 1.0, it is necessary to maintain an appropriate spot size and spatial distance / separation between the optical signals.

[0050] The spot size of an optical signal is related to the divergence angle and the vertical distance between the optical emitter and the projection surface. Referring to Figure 2, if the divergence angle α is constant throughout the optical path, as the vertical distance between the optical emitter and the projection surface increases, the spot size projected onto the projection surface increases (the spot size on plane 1 is smaller than the spot size on plane 2). Similarly, if the vertical distance between the optical emitter and the projection surface is constant, the spot size increases as the divergence angle increases. In the present invention, the final divergence angle of the optical signal entering the eye and the optical distance between the optical emitter and the observer's retina can be modified in several ways, which are described in more detail below.

[0051] To achieve a VA higher than that of normal human vision, the number of distinguishable light signals (e.g., pixels) projected onto a unit area of ​​the retina (i.e., pixel density) must be greater than that required for natural vision. The number of light signals projected onto a unit area of ​​the retina is directly proportional to the number of light signals and the FOV (measured in degrees) that contains those light signals. This means that it is positively correlated with the VA perceived by the observer. In other words, the VA perceived by the observer is positively correlated with the number of distinguishable light signals per degree of FOV. Therefore, the VA perceived by the observer can be increased by increasing the number of distinguishable light signals projected onto each degree of the observer's retina.

[0052] The present invention provides a system and method for enhancing VA to maximize the number of distinguishable, separable optical signals projected per unit angle of FOV (measured in degrees) and create an image frame with the greatest number of distinguishable signals per unit area on the retina, while simultaneously having the greatest FOV and signal density. In one embodiment of the present invention, the system and method for enhancing VA may be implemented as a head-wearable display system, such as AR / VR glasses, an AR / VR helmet, or other similar commercial or medical device. In some other examples, the present invention may be applied to other fixed or non-head-wearable display devices. Below, a head-wearable display system is used to describe an embodiment of the present invention. Furthermore, the head-wearable display system may provide a pixelated image to a viewer. Therefore, the optical signals projected by the optical emitters may correspond to the pixels of the image. However, the present invention is not limited to this embodiment.

[0053] 3 , the head-wearable display system includes a target object detection module 800, a first light emitter 10, a first light redirector 100, a first collimator 1000, and a first combiner 20. The target object detection module 800 receives a plurality of image pixels of a first portion and a second portion of a target object. The target object may be the observer's surroundings, a part of the surroundings, or a specific object in the surroundings. The target object detection module 800 may further include a distance detection unit 801 for determining a depth of the target object or at least a part of the target object. To present a complete three-dimensional virtual image of the target object, the target object detection module 800 and the distance detection unit 801 may measure a plurality of points on the target object and create a three-dimensional profile of the target object, so that a three-dimensional virtual image of the target object may be generated later.

[0054] To achieve a better shooting angle, the target object detection module 800 is adjustably mounted on a frame of the head-wearable display system. For example, the target object detection module 800 has a sliding structure that is inserted into the frame, allowing the target object detection module 800 to slide along a track. The target object detection module 800 is powered by a power cord in the track, and image data captured by the target object detection module 800 is transmitted along a data line in the track.

[0055] In another embodiment, the target object detection module 800 is attached to a frame of the head-wearable display system via a pivot joint. More specifically, the frame is physically connected to the target object detection module 800 via the pivot joint. This pivot joint allows the target object detection module 800 to rotate and adjust the orientation of the target object detection module 800 depending on the application scenario. In this embodiment, the observer can adjust the target object detection module 800 to align with the entire face to capture facial expressions or to align with the outside to capture environmental images. The adjustable design allows the target object detection module 800 to better capture the observer's facial features based on various variations in face shape and / or size.

[0056] The first light emitter 10 emits a plurality of first eye light signals associated with the target object. For example, the plurality of first eye light signals may directly reproduce image pixels of the target object, allowing the observer to view a first eye virtual image of the target object through the head-wearable display system. The first light emitter 10 may generate light pulses to create a pixelated image. For example, the first light emitter 10 may be a laser emitter capable of emitting a light signal or pixel at a time. For example, in some cases, the light emitter may include a red laser diode, a green laser diode, and a blue laser diode. The first light redirector 100 receives the plurality of first eye light signals emitted by the first light emitter 10 and redirects the light direction of the plurality of first eye light signals from the first light emitter 10. The light direction may be changed in multiple spatial dimensions with respect to time such that an image is created by the periodic scanning action of the first light redirector 100, creating an image frame within a certain period of time. The light redirector in this invention may refer to a mechanical or optical element that can dynamically change the direction of light emitted by a light emitter over time. Examples include, but are not limited to, a microelectromechanical system (MEMS) mirror. The first collimator 1000 is disposed between the first light emitter 10 and the first light redirector 100 to collimate multiple first eye light signals from the first light emitter 10. In another embodiment, the first collimator 1000 may be disposed between the first light redirector 100 and the first combiner 20. Furthermore, the first collimator 1000 may change the optical path of the first eye light signals.

[0057] The first combiner 20 is provided to redirect and focus the multiple first ocular light signals toward the first eye of the observer. In some embodiments, the first combiner 20 receives the multiple first ocular light signals from the first light redirector 100 and redirects and focuses the multiple first ocular light signals toward the first eye 50 of the observer. More specifically, as an example, the first light redirector 100 may rotate within a certain angle range or move within a linear displacement range. As a result, the light directions of the multiple first ocular light signals may also change within a certain range, and when the first combiner 20 receives the multiple first ocular light signals (each having a different angle of incidence) from the first light redirector 100, the first combiner 20 redirects each of the first ocular light signals having a different angle of incidence toward the first eye 50 of the observer. The rotation or linear displacement of the first light redirector 100 is predetermined so that multiple first eye light signals are directed to the observer's first eye 50 at a predetermined range of incident angles, which corresponds to the maximum FOV generated by the head-wearable display system.

[0058] In some embodiments of the present invention, the head-wearable display system may have a two-axis design for the combiner so that the pitch and roll (rotation angles along the horizontal and vertical directions) of the combiner may be adjusted. Additionally, the X, Y, and Z positions of the combiner may be adjusted to match the interpupillary distance of each observer. In other embodiments, the X, Y, and Z positions of the combiner may be adjusted individually for each observer.

[0059] 4A-4B, the divergence angle of each of the light signals traveling from the first combiner 20 to the first eye 50 determines the spot size of the light signal presented on the observer's retina. Increasing the divergence angle results in a larger spot size, while decreasing the divergence angle results in a smaller spot size. According to one embodiment, the spot size of the first eye light signal projected onto the retina may be controlled by changing the distance between the first light redirector 100 and the first collimator 1000. Referring to FIGS. 4A-4B, these figures illustrate how changing the distance between the first light redirector 100 and the first collimator 1000 affects the spot size. The light beam in the figures represents the optical path of a single light signal projected by the first light emitter 10. Throughout the optical path of the first eye light signal traveling from the first light emitter 10 to the observer's first eye 50, the optical path of the first eye light signal undergoes several divergence / convergence cycles. The cross-sectional area (corresponding to spot size) of the light beam changes along different locations in the optical path. In other words, the spot size is different at different locations in the optical path. Changing the total optical path between the light emitter and the observer's eye changes the cross-sectional area projected onto the observer's retina, thereby changing the spot size. Obviously, the spot size perceived by the observer's eye may also depend on the specifics of each observer's eye, such as the eye's total refractive power, axial length, and retinal condition. These factors must be taken into consideration when performing initial calibration for different users / observers. In both Figures 4A and 4B, the first-eye light signal gradually converges after exiting the first combiner 20, but forms beam waists (where the cross-sectional area of ​​the beam is smallest) at different locations. In Figure 4A, the light signal forms a beam waist and diverges before entering the first combiner 20. After being reflected by the first combiner 20, the light signal converges again before entering the observer's first eye 50. In Figure 4B, the beam waist is formed between the first combiner 20 and the observer's first eye 50. As a result, the spot size of the first-eye light signal provided to the observer's first eye 50 in these two figures is different.In this embodiment, the position of the beam waist can be adjusted by changing the position of the first collimator 1000, thereby adjusting the spot size of the multiple first ocular light signals projected onto the observer's first eye 50 (e.g., retina) so that the multiple first ocular light signals are separable and distinguishable according to the Rayleigh criterion. In some other examples, the position of the beam waist can be adjusted by changing the distance between the first light redirector 100 and the first collimator 1000. Obviously, by manipulating the distance between the first light redirector 100 and the first collimator 1000, the most appropriate spot size and beam separation for observers with different ocular conditions can be evaluated and determined. In general, the curvature of the collimator and combiner can be customized for different users, as these parameters can also affect the spot size. Furthermore, since the spot sizes in these two figures are different, the spatial distance / separation between the centers of two adjacent first ocular light signals may also be different.

[0060] Below, we describe several methods for changing the ratio of the number of light signals within the observer's FOV (the ratio is measured in number of primary eye light signals per degree) to change the VA perceived by the observer. These methods include changing the spot size of the light signals and the spatial separation between adjacent light signals.

[0061] Referring to Figures 5A and 5B, in one embodiment, the spot size can be adjusted by changing the projection period of a single pixel (e.g., via control software). The light emitter generates an image frame by projecting one light signal / pixel of the image at a time. The light emitter then changes the projection position via movement of the light redirector to generate another pixel of the image at the new location. Thus, when the projection period of the light signal is shortened, the width of the pixel in the direction of rotation of the light redirector is shortened, and when the projection period of the light signal is lengthened, the width of the pixel in the direction of rotation of the light redirector is lengthened. As a result, the spot size can be adjusted in real time to meet the Rayleigh criterion for different VA settings. In a variation of this embodiment, the projection period can be effectively extended by repeatedly projecting the same pixel or image pixel onto pixels in different rows or columns. In Figure 5A, the projection period can be effectively extended by repeatedly projecting the same pixel or image pixel onto pixels in different rows or columns. In Figure 5A, the light emission pulse has a longer projection period compared to Figure 5B. If the swing frequency of the light redirector is the same in FIG. 5A and FIG. 5B, the longer the projection period, the wider the area the optical signal can sweep, resulting in a larger spot size of the optical signal.

[0062] Considering that changing the spot size also changes the spacing between the optical signals, it is necessary to deal with an increase or decrease in the distance between the optical signals. Various embodiments for changing the spacing between the optical signals are described below.

[0063] According to one embodiment of the present invention, the speed at which the light redirector changes direction (i.e., swing frequency) can be changed to change the distance between each projected optical signal. As previously described, a light redirector of the present invention may be capable of redirecting light in one axis or two separate axes (e.g., a two-dimensional MEMS mirror). As an example, a two-dimensional MEMS mirror can rapidly deflect optical signals up to an optical scan angle of approximately 30° in both axes. However, the maximum scan angle in one axis (the main scan axis) may be greater than the other axis (the secondary scan axis). The swing frequency or swing amplitude of the MEMS mirror can be controlled by applying drive voltages / electromagnetic fields of different frequencies and amplitudes to the MEMS mirror, as is readily known in the art. According to this embodiment, the first light redirector 100 changes the first or second coordinate components of the plurality of first eye light signals at a non-constant swing frequency (or swing speed, which is how fast the light redirector rotates or moves relative to a reference). The first or second coordinate component may be an x- or y-coordinate component in a Cartesian coordinate system, or a θ- and φ-coordinate component in a polar coordinate system. When the present invention displays an image at a higher VA setting, the spot size of the light signals may be reduced. The swing speed of the first light redirector 100 may be reduced to project adjacent light signals with a smaller angular displacement, thus projecting the light signals closer together onto the observer's retina (see FIG. 6). As a result, the number of light signals projected per unit of FOA (e.g., degree) increases, and the VA perceived by the observer increases. Because the swing angle of the light redirector is constant, the result is a virtual image frame with the same frame size but a greater light signal density.

[0064] To accommodate the reduced swing frequency while maintaining the same frame rate for image projection, the scanning area of ​​the light redirector can be reduced, as shown in Figure 6. This reduces the spatial separation between each projected light signal, which in turn reduces the FOV. However, reducing the FOV can actually increase the VA.

[0065] As shown in Figures 7A, 7B, and 7C, in one embodiment of the present invention, the size of multiple first eye light signals can be adjusted so that there is little to no separation between adjacent first eye light signals. When light signals are projected onto a cross section of the optical path, a light spot area is generated. As shown in Figure 7B, the light spot areas of two adjacent light signals on the cross section of the optical path are interconnected. Therefore, it is not necessary to change the swing frequency of the light redirector or the emission frequency of the light emitter. However, in this embodiment, the minimum light spot size is limited, which also restricts the maximum VA. Note that Figures 7A and 7C show that there may be overlap between adjacent light signals (e.g., first eye light signals), but the human eye can still distinguish the two signals as long as the Rayleigh criterion is satisfied.

[0066] To maintain a sufficient frame rate, in another embodiment of the present invention, only a portion of the virtual image frame is projected with a high number of light signals per unit of FOA (e.g., per degree) (high VA). The idea behind this embodiment is that when the human eye views a target object, the eye's visual axis is directed toward the target object, and the image of the target object is focused on the macula (the most sensitive part of the retina) of the eye, thus making the target object appear to be in the central FOV of vision. For a target object in an image, other parts of the image may be less clear because they may be projected onto other parts of the retina that are less sensitive to light. Based on the above-mentioned nature of human vision, the present invention provides a central FOV (or first FOV) representing a first part (central part) of the virtual image frame of the target object with a higher number of light signals per degree of FOV than a peripheral FOV (or second FOV) representing a second part (peripheral part) of the virtual image frame of the target object, thereby allowing a user of the present invention to view the central FOV of the target object with a higher pixel density (higher VA). On the other hand, the image in the peripheral FOV of the target object does not need to be as clear as the central FOV because the human eye cannot perceive higher quality images in the peripheral FOV. In other words, a first portion of the target object in the first FOV has a higher number of first eye light signals per degree than a second portion of the target object in the second FOV. In one embodiment, when the first light emitter 10 projects light signals into the central FOV, the number of light signals (or pixels) projected into the central FOV can be manipulated by changing the swing frequency of the light redirector. In addition to changing the swing frequency, the number of light signals (or pixels) projected into the central FOV can be further varied by changing the projection frequency or projection period of the light signals, as described above. By implementing these methods, the time it takes the light emitter to generate a frame (frame rate) can be maintained at a higher rate. The resulting virtual image created by this method will have inconsistent pixel density.

[0067] For example, under normal conditions (when the swing frequency is at a default value), the first light emitter 10 and the first light redirector 100 may be capable of forming an image frame of a default resolution (e.g., 1280 x 720 pixels) within a first spatial range (e.g., 40 degrees horizontally or 22.5 degrees vertically). The spatial range referred to in this disclosure represents a range in both the first and second coordinate components and may be expressed in two coordinates. In this embodiment, the first spatial range corresponds to the FOV of the first eye 50. The first image frame is divided into two FOVs: a peripheral FOV and a central FOV. The central FOV of the image frame is provided with a larger number of light signals per degree of FOV (higher light signal / pixel density projected onto the retina) than the peripheral FOV. For example, the central FOV in both coordinate components may be set to 10 degrees of the total FOV in both coordinate components, and both peripheral FOVs may be set to 15 degrees of the total FOV. If the observer selects a higher VA setting, the spot size of the light signals in the central FOV may be reduced, while the swing speed of the light redirector may be correspondingly reduced to compensate for the increased separation between the light signals. Light signals in the peripheral FOV may be generated with a default spot size at the default swing frequency of the light redirector. As a result, the observer may perceive a higher VA in the central FOV than in the peripheral FOV in an image frame F1 with inconsistent pixel density. Referring to FIG. 8 , the following illustrates one specific example for varying pixel density in one coordinate component (e.g., horizontal or vertical). In this example, the total FOV in one direction may be 40 degrees, the central FOV may be set to 10 degrees, and the default resolution displayed per frame is 1280 x 720. If the target VA is 2.0, the total number of pixels required in the central FOV is: 60 x 2 x 10 = 1200 pixels (60 is the number of pixels per degree of FOV required for VA = 1.0) For the remaining FOV (peripheral FOV), the pixel density remains the same. The total number of pixels in the direction of the peripheral FOV is: 1280 x 30 / 40 = 960 pixels VA=960 / 30 / 60=0.53 During the formation of the first image frame, the first light redirector 100 continuously rotates and redirects the projection direction of the first light emitter 10 to generate the first image frame row by row or column by column. In particular, the first light emitter 10 generates the first image frame by projecting one pixel of the image at a time, and then the first light redirector 100 redirects the first eye light signal to generate another pixel of the image at a new location, often immediately adjacent horizontally or vertically to the previous image pixel. Thus, after a period of time, the first light emitter 10 generates a row of image pixels or a column of image pixels (e.g., 1280 x 1 or 1 x 720). The first light redirector 100 then redirects the first eye light signal to the next row or column and continues generating the second row or column of image pixels. This process is repeated until a complete image frame (e.g., a complete image of 1280 x 720 pixels) is generated.

[0068] In some embodiments, for a constant light emitter projection frequency, the swing frequency of the light redirector can be decreased to increase the pixel density in the sub-scan direction of the light redirector (by decreasing the spatial separation between adjacent pixels). To increase pixel density in the main scan direction, the light emitter light projection frequency can be increased. For example, the light redirector swing frequency can be halved to increase the number of pixels in the sub-scan direction from 720p to 1440p. The light emitter projection frequency can be doubled to increase the number of pixels in the main scan direction from 720p to 1440p.

[0069] In another example, it may be beneficial to implement two one-dimensional light redirectors so that the swing frequency of the light redirector in both the horizontal and vertical directions can be varied depending on different regions of the FOV. As previously mentioned, the swing frequency of the horizontal and vertical light redirectors varies depending on the horizontal and vertical position. While projecting an image into the central FOV, the projection speed can be increased and / or the swing frequency of the horizontal and vertical light redirectors can be decreased to project a higher density of pixels or image pixels into the central FOV (thereby increasing the VA in the central FOV). In the peripheral FOV, the projection speed and / or swing frequency of the light redirector in both directions can be returned to normal.

[0070] In a variation of the above embodiment, an image in the central FOV may be generated with a higher VA, while the light emitter does not emit any light signals related to the peripheral FOV. In particular, in an AR head-wearable display system, only a portion of the target object (e.g., a more distant object) may be selected by the observer and displayed with a higher VA. Other portions of the target object may be observed by an observer with natural vision. Therefore, only a small portion of the total FOV needs to be displayed with a high number of light signals per degree of FOV, and the remaining FOV is displayed with zero light signals per degree of FOV. Because a smaller FOV needs to be scanned by the light redirector, the frame rate may be maintained at a relatively high level.

[0071] As mentioned above, achieving VA that exceeds that of normal human vision requires increasing the number of distinguishable light signals projected onto the observer's retina per unit FOV. To achieve this, the present invention considers factors such as the spot size of the light signals projected onto the observer's retina, the size of the FOV perceived by the observer, and the spatial separation between each light signal. In one embodiment of the present invention, the spot size is related to the size of the pixels projected onto the retina. If the spot size is too large or the spatial separation between adjacent pixels (i.e., the spatial separation between the centers of adjacent pixels) is too small, the pixels may overlap each other, making the pixels or images indistinguishable. On the other hand, if the spot size is too small or the separation between pixels is too large, the total number of pixels that can be packed into a unit angle (or area of ​​the retina) of field of view is reduced. In either case, VA decreases. As an example, the following table illustrates the relationship between VA and the above-mentioned important factors. In this example, a laser projector is used as the light emitter. The resolution of the laser projector in this invention is typically 1280 x 720 or 1920 x 1080 pixels. However, the resolution of the light emitter is not limited to these values. The data in the following table is based on experimental results. [Table 1]

[0072] According to the table above, to achieve VA1.0, the required number of distinguishable pixels (meeting the Rayleigh criterion) within 1 degree of FOV is 60. If using a laser projector capable of producing 1280x720p resolution, the required number of distinguishable pixels within 10.67 degrees of FOV is 120 to create VA2.0. For VA3.0, the required number of distinguishable pixels within 7.1 degrees of FOV is 180. For VA4.0, the required number of distinguishable pixels within 5.33 degrees of FOV is 240. If using a laser projector capable of producing 1920x1080p resolution, the required number of distinguishable pixels within 16 degrees of FOV is 120 to create VA2.0. For VA4.0, the required number of distinguishable pixels within 8 degrees of FOV is 240.

[0073] Furthermore, to achieve a VA above normal vision, the appropriate radius of curvature (and therefore focal length) of the combiner must be selected to suit different users. Once selected, the distance between the light redirector and collimator can be adjusted to project the light signal with the appropriate spot size so that the observer experiences the desired VA setting.

[0074] An exemplary implementation of the present invention is described below. A head-wearable display system may be used as a visual aid to enable an observer to obtain higher visual acuity than normal human vision (e.g., higher than VA 1.0). A target object detection module 800 captures multiple image pixels of a target object. Depending on the physical size of the target object, the image pixels may be associated with a portion of the target object or the entire target object. Because portions of the target object may vary in position and depth relative to the observer, the target object detection module 800 determines the distance or relative depth of at least a portion of the target object. To better understand the present application, assume that there are two objects with the same physical size in the observer's surroundings. When the observer views both objects, the object farther from the observer (the object with a larger depth) occupies a smaller portion of the total FOV than the object closer to the observer (the object with a smaller depth). In order for the observer to see the object farther from the observer with the same level of detail as the object closer to the observer, the object farther from the observer needs to be displayed with a higher VA (e.g., greater than VA 1.0). Therefore, as described above, to present virtual images of different portions of a target object having different depths, the dispersion angle of each of the multiple light signals and the spatial separation between the centers of any two adjacent light signals presenting an image of the object need to be changed according to the change in depth. Furthermore, the target object referred to herein may refer to the observer's surroundings or individual objects within the surroundings. If the target object occupies a relatively large portion of the observer's total FOV, the virtual image of the target object may be divided into multiple FOVs. Depending on the depths of different portions of the target object, the ratio of the number of the multiple first eye light signals to the first FOV containing the first portion of the target object (i.e., the number of first eye light signals per degree) may exceed the ratio of the number of the multiple first eye light signals to the second FOV containing the second portion of the target object. In this embodiment, the first FOV and the second FOV may each represent a different portion of the target object.

[0075] In a variation of the above embodiment, when the target object is moving relative to the observer, the target object detection module 800 captures image pixels of the moving target object. The distance detection unit 801 of the target object detection module 800 dynamically determines the distance or depth of the surrounding moving target object. The FOV of the virtual image of the moving target object changes according to the position of the moving target object. To compensate for the change in FOV, the dispersion angle of each of the multiple light signals representing the image of the moving target object and the spatial separation between the centers of any two adjacent light signals need to be changed according to the depth of the object. As a result, the ratio of the number of the multiple first eye light signals to the first FOV of the target object (e.g., when the target object is far away) may exceed the ratio of the number of the multiple first eye light signals to the second FOV of the target object (e.g., when the target object is close). In this embodiment, the first FOV and the second FOV may respectively represent different virtual images of the moving target object at different times.

[0076] Another aspect of the present invention is the ability to generate images of portions of a target object or target object with high VA and depth perception.

[0077] 9 , in some embodiments, the present invention includes a first light projector 1, which includes a first light emitter 10, a first light redirector 100, a first collimator 1000, and a first combiner 20. The present invention also includes a second light projector 3, which includes a second light emitter 30 that emits a plurality of second eye light signals corresponding to a plurality of first eye light signals to display a second-eye virtual image of a target object, a second collimator 3000 that adjusts the beam waist position of each of the plurality of second eye light signals so that the plurality of second eye light signals are separable from each other, and a second light redirector 300 that changes the light direction of each of the plurality of second eye light signals emitted from the second light emitter 30. The present invention further includes a second combiner 40 that redirects and converges the plurality of second eye light signals toward a second eye 60 of an observer. The second light emitter 30, the second collimator 3000, the second light redirector 300, and the second combiner 40 are functionally similar to their respective counterparts. As an example, the plurality of second eye light signals are perceived by the left eye of the observer, and the plurality of first eye light signals are perceived by the right eye of the observer (or vice versa). Each of the plurality of second eye light signals has a corresponding first eye light signal. That is, the first eye light signal and the corresponding second eye light signal are fused to create a virtual binocular pixel of the binocular virtual image. Each of the first eye light signal and each of the second eye light signal have respective angles of incidence entering the first eye 50 and the second eye 60. Furthermore, the second light emitter 30, the second collimator 3000, the second light redirector 300, and the second combiner 40 may change the spot size by changing the position of the beam waist of the plurality of second eye light signals and the spatial separation between their counterparts as well as adjacent second eye light signals. The first eye 50 and the second eye 60 perceive the first eye light signal and the corresponding second eye light signal to generate binocular vision, and the first eye light signal and the corresponding second eye light signal are fused to form a binocular pixel for the observer. In particular, in this embodiment, referring to Figures 10 and 11, the first eye light signal emitted by the first light projector 1 and redirected from the first combiner 20 enters the first eye 50 of the observer.The corresponding second eye light signal emitted by the second light projector 3 and redirected from the second combiner 40 enters the second eye 60 of the observer. The first eye light signal and the second eye light signal are perceived by the observer to form a first virtual binocular pixel 72 of the virtual object 70 having a first depth (D1) associated with a first angle (θ1) between the optical path extension of the redirected first eye light signal and the optical path extension of the redirected second eye light signal. More specifically, the optical path extensions of the first eye light signal and the second eye light signal are on opposite sides of the first combiner 20 and the second combiner 40 and virtually converge at a position P1. As the first angle θ1 between the two optical path extensions of the first eye light signal and the second eye light signal increases, the first depth d1 perceived by the observer decreases. On the other hand, as the first angle θ1 decreases, the first depth d1 perceived by the observer increases. The first depth d1 of the first virtual binocular pixel 72 can be approximately calculated by the following formula. tan(θ1 / 2)=(pupillary distance) / 2d1

[0078] 9-12, when applying the above-described method for forming image frames, pixels in the first image frame F1 and corresponding pixels in the second image frame F2 form virtual binocular pixels at a first depth associated with a first angle between the first and second eye light signals projected to the observer's eyes. Upon receiving the plurality of light signals, the observer perceives a plurality of right-side pixels of the object in the first image frame F1 within a region A bounded by an extension of the redirected second eye light signals from the combiner. Region A is referred to as the FOV of the second eye 60. Similarly, the plurality of first eye light signals in the second image frame F2 are redirected by the first combiner 20, pass through the center of the left pupil 62, and are ultimately received by the left retina 64. Upon receiving the redirected first eye light signals, the observer perceives a plurality of left-side pixels of the object within a region B bounded by an extension of the redirected first eye light signals. Region B is referred to as the FOV of the first eye 50. When both a plurality of right pixels from the first image frame F1 and a plurality of left pixels from the second image frame F2 are displayed in region C, which is the overlapping portion of region A and region B, at least one second eye light signal displaying one right pixel and one first eye light signal displaying one left pixel are fused to display a virtual binocular pixel of a particular depth in region C. The depth is related to the angle between the redirected second eye light signal and the redirected first eye light signal. Such an angle is also referred to as the convergence angle.

[0079] 9-12, as described above, the plurality of second ocular light signals are generated by the second light projector 3, redirected by the second combiner 40, and then scanned directly by the right retina to form a right retinal image on the right retina. Similarly, the plurality of first ocular light signals are generated by the first light projector 1, redirected by the first combiner 20, and then scanned by the left retina to form a left retinal image on the left retina. In one embodiment, the right retinal image includes 36 right pixels from the first image frame F1 in a 6x6 array, and the left retinal image includes 36 left pixels from the second image frame F2 in a 6x6 array (FIG. 11). In another embodiment, the right retinal image includes 921,600 right pixels from the first image frame F1 in a 1280x720 array, and the left retinal image includes 921,600 left pixels from the second image frame F2 in a 1280x720 array. The object display system is configured to generate a plurality of second-eye light signals and a corresponding plurality of first-eye light signals, each forming a right retinal image on the right retina and a left retinal image on the left retina. As a result, the observer perceives a virtual binocular object with a specific depth within region C through image fusion. The second-eye light signal 16 from the second light projector 3 is received and reflected by the second combiner 40. The redirected second-eye light signal 16' passes through the right pupil 52 to reach the observer's right retina and forms a right pixel R34. The corresponding first-eye light signal 36 from the first light projector 1 is received and reflected by the first combiner 20. The redirected first light signal 36' passes through the left pupil 62 to reach the observer's left retina and forms a left pixel L33. As a result of image fusion, the observer perceives the virtual binocular object at multiple depths, where the depths are determined by the angles between the multiple redirected second eye light signals and the corresponding multiple redirected first eye light signals for the same object. The angles between the redirected second eye light signals and the corresponding redirected first eye light signals are determined by the horizontal distance between the right pixel and the left pixel. In other words, the deeper a virtual binocular pixel is perceived by the observer, the smaller the relative horizontal distance in the X-axis between the right pixel and the left pixel forming such virtual binocular pixel.For example, the second virtual binocular pixel 74 is perceived by the observer as having a greater depth (i.e., a greater distance from the observer) than the first virtual binocular pixel 72. Therefore, the horizontal distance between the second right pixel and the second left pixel on the retinal image is smaller than the horizontal distance between the first right pixel and the first left pixel.

[0080] In a variation of the above embodiment, a head-wearable display system according to the present invention may have a single combiner that covers both of the observer's eyes. The radius of curvature of the combiner is designed to receive and converge the plurality of first-eye light signals and the plurality of second-eye light signals, respectively. Each of the plurality of second-eye light signals has a divergence angle when propagating from the first combiner 20 to the observer's second eye 60.

[0081] The above method can present a virtual image of a portion of a target object (e.g., an object within a target object) consisting of multiple first and second eye light signals at multiple depths in an AR environment, allowing the observer to view the virtual image in the most realistic manner (with depth perception and a 3D effect). Furthermore, based on the multiple depths of different points in the surrounding area, a virtual image can be superimposed on a real image of the surrounding area as a supplement, allowing the observer to view the surrounding area with a higher VA. In this embodiment, image information captured by the target object detection module 800 unit can be superimposed on the image viewed by the observer. More specifically, in some cases, the depth or position of a virtual image (e.g., an object within a target object) can be set to match the depth or position of an interactive object (e.g., the surrounding environment), making the virtual image appear as if it were on or near the interactive object. If necessary, the virtual image can also be superimposed on the interactive object. In another embodiment, the present invention is implemented as a VR system, and the observer's vision can rely entirely on the image information provided by the VR system.

[0082] In the above embodiment, the eye tracking device 802 may determine the gaze positions of the first eye 50 and the second eye 60 of the observer, respectively. The eye tracking device 802 is configured to track at least the positions of both pupils of the observer. The eye tracking module may also be configured to provide more information about the observer's eyes, including, but not limited to, the eye movement, pupil size, gaze angle (field of view), and convergence angle of each eye of the observer. Such eye information may be used to determine the gaze position and gaze depth of the observer, as well as the direction and position of projecting the light signal of the virtual object. The eye tracking device may include a first camera for tracking the first eye 50 and a second camera for tracking the second eye 60. In addition to conventional eye tracking cameras, the first and second cameras may be constructed using micro-MEMS technology. The first and second cameras may use infrared light emitters and sensors to detect and derive various eye information. The eye-tracking device 802 may further include an integrated inertial measurement unit (IMU), which is an electronic device that combines accelerometers, gyroscopes, and possibly magnetometers to measure and report specific forces, angular velocities, and possibly orientations of an object. The following describes an exemplary implementation of the present invention in which both the observer's first and second eyes are equipped with light emitters, collimators, light redirectors, and combiners to achieve visual capabilities higher than normal human vision (e.g., higher than VA1.0). The eye-tracking device 802 determines the observer's gaze fixation position to determine the portion of the target object the observer is looking at. The target object detection module 800 captures multiple image pixels of the target object. The multiple image pixels may relate to a portion or the entire target object. Because each portion of the target object may vary in position and depth relative to the observer, the target object detection module 800 needs to determine the distance or corresponding depth of at least a portion of the target object the observer is gaze fixating.As described above, to present virtual images of different portions of a target object having different depths, the dispersion angle of each of the multiple light signals and the spatial separation between the centers of any two adjacent light signals presenting the image of the object need to be changed according to the change in depth. Furthermore, the target object referred to herein may refer to the observer's surroundings or individual objects within the surroundings. If the target object or a portion of the target object occupies a relatively large portion of the observer's total FOV, the virtual image of the target object may be divided into multiple FOVs. Depending on the gaze position on the target object, the ratio of the number of the multiple first eye signals to the first FOV containing the first portion of the target object (i.e., the number of first eye signals per degree) may exceed the ratio of the number of the multiple first eye signals to the second FOV containing the second portion of the target object, while the ratio of the number of the multiple second eye signals to the third FOV containing the first portion of the target object (i.e., the number of second eye signals per degree) may exceed the ratio of the number of the multiple second eye signals to the fourth FOV containing the second portion of the target object. The first FOV of the first eye corresponds to the third FOV of the second eye, both of which present a first portion of the target object. The second FOV of the first eye corresponds to the fourth FOV of the second eye, both of which present a second portion of the target object. In this embodiment, the spot sizes and spatial separations of the multiple first-eye light signals and second-eye light signals are dynamically changed according to the observer's fixation position.

[0083] The dispersion angle of each of the multiple optical signals presenting the image of the above-mentioned target object and the spatial separation between the centers of any two adjacent optical signals may be changed according to the above-mentioned method, i.e., by changing the projection time of the optical emitter, the distance between the combiner and the collimator, the projection frequency of the optical emitter, and the swing frequency of the light redirector. In practice, the observer's eyes may constantly change their fixation position to view different objects or different parts of the target object having different three-dimensional positions (including depth). Alternatively, in some cases, the observer's eyes may be fixating on a moving object, and the observer needs to constantly change their fixation position. Therefore, the projection time of the optical emitter, the distance between the combiner and the collimator, the projection frequency of the optical emitter, and the swing frequency of the light redirector may need to be dynamically changed depending on the fixation position (and therefore the depth of the object the observer is fixating).

[0084] 13-14, in yet another variation of this embodiment, an optical assembly may be disposed between the above-described light emitter and collimator to change the predetermined cross-sectional area of ​​the optical path of the multiple optical signals. Specifically, the optical assembly includes a lens that may be implemented to change the optical path of the multiple first optical signals from the first light emitter 10 to the first combiner 20 to change the projected area or cross-sectional area (i.e., spot size) of each of the multiple first optical signals. For example, referring to FIG. 13, the optical assembly includes lens_1 and lens_2. Lens_1 and lens_2 are convex lenses. The light emitter is originally positioned at the focal length of lens_1. When lens_1 is moved to a new position shown as lens_1', the distance between the light emitter and lens_1 increases, thereby increasing the amount of light divergence angle from the LBS. This increases the projected area or cross-sectional size of each of the multiple first optical signals, and also increases the spot size of the optical signals. In another embodiment, referring to FIG. 14 , the optical assembly includes lens_1, lens_2, and LBS. Lens_1 and lens_2 are convex lenses. An optical emitter is disposed at the focal length of lens_1, and the optical signal emitted by the optical emitter becomes a substantially parallel optical signal after passing through lens_1. In this mode, the focal length of lens_2 can be selected to reduce the FOV. For example, changing the focal length of lens_2 from 50 mm to 100 mm (and moving the pupil at the focus of lens_2 100 mm away from lens_2) can reduce the FOV by half. When the present invention is realized in the form of a head-wearable device or AR / VR glasses, lens_2 can be implemented as a combiner. However, in other embodiments, lens_2 can also be implemented as other optical elements.

[0085] In some embodiments, the methods shown in Figures 13 and 14 can be implemented simultaneously to further improve the FOV. When the present invention is realized in the form of a head-wearable device or AR / VR glasses, Lens_2 can be implemented as a combiner. However, in other embodiments, Lens_2 can also be implemented as other optical elements.

[0086] The present invention may assist observers with corneal and retinal disorders (e.g., age-related macular degeneration). For people with normal eye conditions, the optimal area for sensing light is the macula, but for people with macular degeneration or other eye diseases, other areas of the eye may be preferred for sensing light and receiving image pixels. Therefore, the present invention can be used to project an optical signal onto a healthy area of ​​the retina to generate an image of the surrounding environment for the observer to see. Before implementing the present invention, corneal topography and retinal circumference may be used to find the optimal optical path and position for the optical signal projected onto the observer's eye. Meanwhile, to project light onto the least defective part of the retina, it is necessary to identify the optimal angle of incidence for entering the least defective corneal area. To achieve this function, the combiner may be designed to have an elliptical concave surface and / or a customized angle of reflection.

[0087] In the present invention, the combiners 20, 40 receive, converge, and redirect the multiple optical signals generated by the optical emitters 10, 30. In one embodiment, the combiners 20, 40 reflect the multiple optical signals so that the redirected optical signals are on the same side of the combiner 20, 40 as the incident optical signals. In another embodiment, the combiners 20, 40 refract the multiple optical signals so that the redirected optical signals are on a different side of the combiner 20, 40 from the incident optical signals. When the combiners 20, 40 also function as refractors, the reflectivity of the combiner can vary widely, such as from 20% to 80%, depending on the power of the optical signal generator. Those skilled in the art will know how to determine the appropriate reflectivity based on the characteristics of the optical emitters 10, 30 and the combiners 20, 40. Furthermore, in one embodiment, the combiners 20, 40 are optically transparent to ambient (environmental) light from the opposite side of the incident optical signals. The degree of transparency can vary widely depending on the application. For AR / MR applications, a transparency of 50% or greater is preferred, e.g., approximately 75% in one embodiment. In addition to redirecting optical signals, the combiners 20, 40 may converge multiple optical signals forming a combiner image so that they can pass through the pupil and reach the retinas of both eyes of the observer. The combiners 20, 40 may be made of glass or plastic materials, like lenses, and may be coated with certain materials, such as metal, to be partially transparent and partially reflective. One advantage of using a reflective combiner instead of a conventional waveguide to guide optical signals to the observer's eye is that it eliminates the problem of undesirable diffraction effects, such as multiple shadows and color shifts. The combiners 20, 40 may also be holographic combiners, but these are not preferred because diffraction effects can cause multiple shadows and RGB shifts. In some embodiments, it may be desirable to avoid the use of holographic combiners, or in other embodiments, the present invention may utilize shutters to significantly reduce ambient light entering the observer's eyes. The shutters may be activated by reducing the transparency of the first and second combiners.

[0088] In some embodiments, the present invention can be implemented as a head-wearable device for vision correction or vision training. The present invention can be used to correct or improve eye disorders such as, but not limited to, myopia, hyperopia, strabismus, amblyopia, and convergence disorders. The principle for correcting or improving the aforementioned disorders is to provide more visual stimulation to the observer's eyes. In other words, providing appropriate stimulation to the eyes can promote improvement of VA and eye muscle movement. Referring to FIG. 15 , as an example, the present invention can be used to correct the vision of people with myopia or hyperopia. In this embodiment, a head-wearable device equipped with an AR / VR system can capture real-time images of a target object or surrounding environment viewed by the observer via a target object detection module 800 and project pixelated images with depth perception to the observer. The system's pixelated images can be focused at a desired location using the aforementioned method. For example, the pixelated image can be focused just in front of the retina for people with myopia or just behind the retina for people with hyperopia, stimulating the ciliary muscle to adjust the eye's lens so that the image is properly focused on the retina. Using this method, you can train your eye muscles.

[0089] Referring to Figure 16, yet another embodiment of the head-wearable display system of the present invention is shown. More specifically, in addition to the head-wearable display system shown in Figure 9, the head-wearable display system shown in Figure 16 further includes a focusing element. Note that although the head-wearable display system shown in Figure 16 is a binocular head-wearable display system targeted at the first eye 50 and the second eye 60 of an observer, in some embodiments, the head-wearable display system shown in Figure 16 may be a monocular head-wearable display system targeted at only the first eye 50 or the second eye 60 of an observer.

[0090] For the first eye 50 of the observer, the head-wearable display system may include a first light emitter 10, a first collimator 1000, a first focusing element 10000, a first light redirector 100, a first combiner 20, and a target object detection module 800. The first light emitter 10, the first collimator 1000, the first light redirector 100, the first combiner 20, and the target object detection module 800 are substantially the same as those disclosed above, and therefore further details will not be provided here. Taking FIG. 16 as an example, the first focusing element 10000 may be disposed between the first collimator 1000 and the first light redirector 100. The first focusing element 10000 may be used to adjust the beam waist size of each of the multiple first-eye light signals and may adjust the spot size of the multiple first-eye signals on the first eye 50 of the observer. In some embodiments, the first focusing element 10000 may be an optical component known to those skilled in the art, such as a plano-convex lens. Furthermore, in some embodiments, the distance between the first focusing element 10000 and the first light emitter 10 may be between 6.5 mm and 20.0 mm, and may be 12.0 mm, for example. When the first focusing element 10000 is positioned closer to the first light emitter 10, the collimated first eye light signals are focused faster, and the beam waist of each of the collimated and focused first eye light signals emitted by the first light redirector 100 is reduced, thereby adjusting the spot size of the first eye light signals on the observer's first eye 50 accordingly. Conversely, when the first focusing element 10000 is positioned farther from the first light emitter 10, the collimated multiple first eye light signals are focused more slowly, the beam waist of each of the collimated and focused multiple first eye light signals emitted by the first light redirector 100 becomes larger, and the spot size of the multiple first eye light signals on the observer's first eye 50 is adjusted accordingly. In this manner, the head wearable display system may optimize the VA of the observer's first eye 50 through the configuration of the first focusing element 10000.

[0091] Also, taking Figure 16 as an example, the first light projector 1 shown in Figure 16 may include a first light emitter 10, a first collimator 1000, a first focusing element 10000, and a first light redirector 100, in that order, and may emit a plurality of collimated, focused, and redirected first-eye light signals toward a first combiner 20, thereby displaying first-eye virtual images of a first part and a second part of a target object to an observer. More specifically, taking FIG. 16 as an example, a first light emitter 10 may be used to emit multiple first eye light signals to display first eye virtual images of a first portion and a second portion of a target object to an observer, then a first collimator 1000 may adjust the beam waist position of each of the multiple first eye light signals emitted by the first light emitter 10 to separate the multiple first eye light signals from each other, then a first focusing element 10000 may adjust the beam waist size of each of the multiple collimated first eye light signals to adjust the spot size of the multiple first eye light signals on the observer's first eye 50, and then a first light direction changer 100 may individually change the light direction of each of the multiple collimated, focused first eye light signals so that the first light direction changer 100 can direct the multiple first eye light signals to the first combiner 20 at a first eye light incidence angle θ1.

[0092] Also, for the second eye 60 of the observer, the head-wearable display system may include a second light emitter 30, a second collimator 3000, a second focusing element 30000, a second light redirector 300, a second combiner 40, and a target object detection module 800. The second light emitter 30, the second collimator 3000, the second light redirector 300, the second combiner 40, and the target object detection module 800 are substantially the same as those disclosed above, and therefore further details will not be provided here. Taking FIG. 16 as an example, the second focusing element 30000 may be disposed between the second collimator 3000 and the second light redirector 300. The second focusing element 30000 may be used to adjust the beam waist size of each of the multiple second-eye light signals and may adjust the spot size of the multiple second-eye signals on the second eye 60 of the observer. In some embodiments, the second focusing element 30000 may be an optical component known to those skilled in the art, such as a plano-convex lens. Furthermore, in some embodiments, the distance between the second focusing element 30000 and the second light emitter 30 may be between 6.5 mm and 20.0 mm, and may be 12.0 mm, for example. When the second focusing element 30000 is positioned closer to the second light emitter 30, the collimated second eye light signals are focused faster, and the beam waist of each of the collimated and focused second eye light signals emitted by the second light redirector 300 is reduced, thereby adjusting the spot size of the second eye light signals on the observer's second eye 60 accordingly. Conversely, when the second focusing element 30000 is positioned farther from the second light emitter 30, the collimated multiple second eye light signals are focused more slowly, the beam waist of each of the collimated and focused multiple second eye light signals emitted by the second light redirector 300 becomes larger, and the spot size of the multiple second eye light signals on the observer's second eye 60 is adjusted accordingly. In this manner, the head wearable display system may optimize the VA of the observer's second eye 60 through the configuration of the second focusing element 30000.

[0093] Also, taking Figure 16 as an example, the second light projector 3 shown in Figure 16 may include a second light emitter 30, a second collimator 3000, a second focusing element 30000, and a second light redirector 300 in order, and may emit a plurality of collimated, focused, and redirected second-eye light signals toward a second combiner 40, thereby displaying a second portion of the target object and a second-eye virtual image of the second portion to an observer. More specifically, taking FIG. 16 as an example, the second light emitter 30 may be used to emit a plurality of second eye light signals to display a second portion of the target object and a second eye virtual image of the second portion to the observer, then the second collimator 3000 may adjust the beam waist position of each of the plurality of second eye light signals emitted by the second light emitter 30 to separate the plurality of second eye light signals from each other, then the second focusing element 30000 may adjust the beam waist size of each of the plurality of collimated second eye light signals to adjust the spot size of the plurality of second eye light signals on the observer's second eye 60, and then the second light direction changer 300 may individually change the light direction of each of the plurality of collimated, focused second eye light signals so that the second light direction changer 300 can direct the plurality of second eye light signals to the second combiner 40 at a second eye light incidence angle θ3.

[0094] In some embodiments, the head-wearable display system may be a binocular head-wearable display system, and may specifically include a target object detection module 800, a first light emitter 10, a first collimator 1000, a first focusing element 10000, a first light redirector 100, a first combiner 20, a second light emitter 30, a second collimator 3000, a second focusing element 30000, a second light redirector 300, and a second combiner 40, to optimize the VA of the first eye 50 and the second eye 60 of the observer.

[0095] 17, which is a diagram illustrating the effect of a focusing element on an optical signal. Specifically, FIG. 17 may be used to illustrate the effect of a first focusing element on a plurality of first eye optical signals emitted by a first optical emitter, and may be used to illustrate the effect of a second focusing element on a plurality of second eye optical signals emitted by a second optical emitter.

[0096] 17 as an example, when the focusing element (either the first focusing element or the second focusing element) is positioned closer to the light emitter (either the first light emitter or the second light emitter), the multiple collimated light signals (either the multiple first eye light signals or the multiple second eye light signals) are focused earlier, resulting in a smaller beam waist of each of the multiple collimated, focused light signals emitted by the light redirector (either the first light redirector or the second light redirector), thereby adjusting the spot size of the multiple light signals at the observer's eye (either the first eye or the second eye). Conversely, when the focusing element is positioned farther from the light emitter, the multiple collimated light signals are focused later, resulting in a larger beam waist of each of the multiple collimated, focused light signals emitted by the light redirector, thereby adjusting the spot size of the multiple light signals at the observer's eye accordingly. In this way, the head-wearable display system can optimize the VA of the observer's eye (either the first eye or the second eye) through the configuration of the focusing element (either the first focusing element or the second focusing element).

[0097] 18A-18C illustrate the effect of varying the radius of curvature of the focusing element on the spot size. In some embodiments, the radius of curvature of the first focusing element 10000 shown in FIG. 16 can range from −5 mm to −50 mm. Also, in some embodiments, the radius of curvature of the second focusing element 30000 shown in FIG. 16 can range from −5 mm to −50 mm. Different radii of curvature of the focusing element (either the first focusing element 10000 or the second focusing element 30000) result in different focal lengths of the focusing element, resulting in different optical spot sizes of the multiple optical signals on the retina of the observer's eye (either the first eye or the second eye). Specifically, when the radius of curvature of the focusing element is large, the focal length of the focusing element increases, resulting in a larger optical spot size of the multiple optical signals on the retina. Conversely, when the radius of curvature of the focusing element is small, the focal length of the focusing element decreases, resulting in a smaller optical spot size of the multiple optical signals on the retina.

[0098] Taking FIG. 18A as an example, when the radius of curvature of the focusing element (either the first focusing element 10000 or the second focusing element 30000) is −50 mm, the spot size on the retina of the observer's eye (either the first eye or the second eye) is 136 μm × 88 μm. Taking FIG. 18B as an example, when the radius of curvature of the focusing element is −13.4 mm, the spot size on the retina of the observer's eye is 38 μm × 25 μm. Taking FIG. 18C as an example, when the radius of curvature of the focusing element is −5 mm, the spot size on the retina of the observer's eye is 26 μm × 14 μm. This indicates that a head-wearable display system can further optimize the VA of the observer's eye (either the first eye or the second eye) by configuring a focusing element (either the first focusing element or the second focusing element) with a smaller radius of curvature.

[0099] 19A-19C, the effect of varying the angle of incidence on spot size is described. In some embodiments, the multiple first optical light signals emitted by the first light redirector 100 shown in FIG. 16 can be directed to the first combiner 20 at a first optical light angle of incidence θ1, which can range from 15 degrees to 75 degrees. Also, in some embodiments, the multiple second optical light signals emitted by the second light redirector 300 shown in FIG. 16 can be directed to the second combiner 40 at a second optical light angle of incidence θ3, which can range from 15 degrees to 75 degrees. Due to different incidence angles (either the first eye light signals or the second eye light signals) of the multiple light signals emitted from the light redirector (either the first light redirector 100 or the second light redirector 300) toward the combiner (either the first combiner or the second combiner), the corresponding exit angles and focal lengths are also different. This results in different spot sizes of the multiple light signals on the retina of the observer's eye (either the first eye or the second eye). Specifically, when the light redirector directs the multiple light signals toward the combiner at a larger incidence angle, the corresponding exit angle is larger and the focal length is longer, resulting in a larger spot size of the multiple light signals on the retina. Conversely, when the light redirector directs the multiple light signals toward the combiner at a smaller incidence angle, the corresponding exit angle is smaller and the focal length is shorter, resulting in a smaller spot size of the multiple light signals on the retina.

[0100] 19A, when a light redirector (either the first light redirector 100 or the second light redirector 300) directs multiple light signals (either multiple first eye light signals or multiple second eye light signals) to a combiner (either the first combiner or the second combiner) at an incident angle of 75 degrees, the spot size on the retina of an observer's eye (either the first eye or the second eye) is 364 μm × 238 μm. Also, when a light redirector directs multiple light signals to a combiner at an incident angle of 35.5 degrees, the spot size on the retina of an observer's eye is 38 μm × 25 μm. Furthermore, when a light redirector directs multiple light signals to a combiner at an incident angle of 15 degrees, the spot size on the retina of an observer's eye is 29 μm × 19 μm. This indicates that the head-wearable display system can further optimize the VA of the observer's eye (either the first eye or the second eye) by configuring it with a smaller incidence angle (either the first eye light incidence angle θ1 or the second eye light incidence angle θ3).

[0101] Furthermore, in some embodiments, the head-wearable display system can further optimize the VA of the observer's eye (either the first eye or the second eye) by utilizing a configuration of a focusing element (either the first focusing element or the second focusing element) with a small radius of curvature and a small angle of incidence (either the first eye angle of incidence θ1 or the second eye angle of incidence θ3) to achieve an optimized VA effect such as VA1.0, VA1.5, VA2.0, VA2.5, VA3.0, or VA4.0.

[0102] Referring to FIG. 20, this figure shows a head-wearable display system according to an embodiment of the present invention. For simplicity, only one side of the head-wearable display system is shown. Note that the present invention can be applied to one eye of a viewer (e.g., the second eye 60) or both eyes of a viewer. In the present invention, the term "light redirector" refers to any optical element configured to change the direction of light after the light strikes or enters the optical element. For example, the light redirector can be any optical lens, mirror, reflector, refractor, elliptical lens / reflector, spherical lens / reflector, parabolic reflector, aspherical lens / reflector, freeform optical lens / reflector, or hypercurved reflector. In the present invention, the term "substantially equal" is used to describe the optical path lengths of different optical signals. It should be understood that when two optical path lengths are considered "substantially equal," it means that the difference between the two optical path lengths is less than 5%. The term "near" means that an object (i.e., any part of an object) is located as close as possible to a particular location (or another object), but may not be at that location due to measurement errors, manufacturing errors, allowed engineering tolerances, or other types of physical limitations.

[0103] For the observer's second eye 60, the head-wearable display system includes a second light projector 3 (which may include the aforementioned second light emitter, second collimator, second focusing element, and second light redirector), a third light redirector 530, a fourth light redirector 540, a second combiner 40, and the aforementioned target object detection module. The operations between the second light projector 3, the third light redirector 530, the fourth light redirector 540, and the second combiner 40 will be further described below. The second light projector 3 is used to emit a plurality of second-eye light signals. The second light projector 3 changes its projection direction between a first spatial dimension limit (e.g., -m, where -m is the coordinate in the φ direction or x direction of the polar coordinate system) and a second spatial dimension limit (e.g., m, where m is the coordinate in the φ direction or x direction of the polar coordinate system) in a first dimension (such as the x or y coordinate dimension of a Cartesian coordinate system, or the θ or φ coordinate dimension of a polar coordinate system). The first dimension can be the x or y coordinate dimension of a Cartesian coordinate system, or the θ or φ coordinate dimension of a polar coordinate system. The projection direction changes in at least one dimension. When the projection direction changes in two dimensions, an image frame can be formed. For example, if the first and second spatial dimension limits are -m and m, the second light projector 3 emits multiple light signals between -m and m. For example, in certain cases, when the projection direction changes in the x direction (e.g., horizontally), the light signals emitted near the first spatial dimension limit form the left edge of the image frame, and the light signals emitted near the second spatial dimension limit form the right edge of the image frame. For example, the first and second spatial dimension limits may refer to -n and n, and the second light projector 3 emits multiple light signals between -n and n. For example, in some other cases, when the projection direction changes in the y direction (e.g., vertically), the light signals emitted near the first spatial dimension limit form the top edge of the image frame, and the light signals emitted near the second spatial dimension limit form the bottom edge of the image frame.

[0104] The third light redirector 530 and the fourth light redirector 540 receive the plurality of first eye light signals and change the individual directions of the plurality of second eye light signals. The second combiner 40 not only redirects and converges the plurality of second eye light signals toward the observer's second eye 60, but may also receive the plurality of first eye light signals and change the individual directions of the plurality of second eye light signals. Each light signal of the plurality of second eye light signals has a different optical path. The third light redirector 530 receives the plurality of second eye light signals and directs the plurality of second eye light signals to the fourth light redirector 540. The fourth light redirector 540 then directs the plurality of second eye light signals received from the third light redirector 530 to the second combiner 40. The second combiner 40 directs the plurality of second-eye light signals received from the fourth light redirector 540 toward the observer's eye (second eye 60) so that the observer can view an image frame composed of the plurality of second-eye light signals (pixels). The third light redirector 530 and the second combiner 40 may each have at least one focal point. In other embodiments, the third light redirector 530 or the second combiner 40 may have two or more focal points.

[0105] 21, this figure illustrates an embodiment of the present invention. In one embodiment of the present invention, the fourth light redirector 540 is disposed adjacent to (or near) the first focal point 5301 of the third light redirector and the first focal point 401 of the second combiner (e.g., the first focal point 5301 of the third light redirector and the first focal point 401 of the second combiner are at the same spatial location). The third light redirector 530 receives multiple second eye light signals emitted by the second light projector 3 and directs all second eye light signals to the first focal point 5301 of the third light redirector, where multiple second eye light signals with different optical path lengths are focused at the first focal point. The actual size of the fourth light redirector 540 can be much smaller than that of the third light redirector 530 because it is located at the focal point of the third light redirector 530 and requires a small amount of surface area to receive the multiple second eye light signals from the second light redirectors in the second light projector 3. This is particularly advantageous in designing a head wearable display system, as it can significantly reduce the overall size of the head wearable display system. Also, by locating the fourth light redirector 540 adjacent to (or near) the first focal point 5301 of the third light redirector, all light signals from the second light redirectors in the second light projector 3 can be received by the fourth light redirector 540. In this embodiment, the fourth light redirector 540 is also located adjacent to (or near) the first focal point 401 of the second combiner, allowing the second combiner 40 to receive all second eye light signals from the fourth light redirector 540.

[0106] In some cases (see FIG. 21 ), the third light redirector 530 may comprise a third light redirector second focal point 5302. The second light projector 3 is positioned adjacent to (or near) the third light redirector second focal point 5302. This configuration can maximize the range of change in projection direction and ensure that all light signals are received by the second light redirector of the second light projector 3. Note that in the present invention, the third light redirector first focal point 5301, the third light redirector second focal point 5302, and the second combiner first focal point 401 are not aligned in a straight line (are not collinear). In this way, these optical elements may be configured in a more compact manner, thereby reducing the final practical size of the head-wearable display system. As shown in FIG. 21, in certain instances, to ensure that the observer's eyes can benefit from the full FOV created by the optical system of the present invention and to ensure that the observer can see the entire image frame, the observer's eyes are positioned adjacent to (or near) the second focal point 402 of the second combiner.

[0107] Generally, a larger FOV is desired. However, it is well known that as the divergence angle increases, the optical path difference between different optical signals also increases, and the distortion of the image frame becomes larger. In other words, the difference in optical path lengths between multiple optical signals is an important factor contributing to the distortion of the image frame. Referring again to FIG. 21, to solve this problem, in the present invention, at least two optical redirectors (i.e., the third optical redirector 530 and the second combiner 40) are used to balance the difference in optical path lengths between the optical signals. The shape of the third optical redirector 530 is designed to compensate for the difference in optical path lengths, ensuring that the total optical path length from the optical signal emitted near the first spatial dimension limit (corresponding to the edge of the image frame) by the second optical projector 3 to the observer's second eye 60 is approximately equal to the total optical path length from another optical signal emitted near the second spatial dimension limit (corresponding to the opposite edge of the image frame) by the second optical projector 3 to the observer's second eye 60. By using this method, the distortion between the edges of the image frame may be compensated. More specifically, referring to FIG. 21, the optical path length of the optical signal S1 from the fourth optical redirector 540 to the observer's second eye 60 is P13 + P14, and the optical path length of the optical signal S2 from the fourth optical redirector 540 to the observer's second eye 60 is P23 + P24. When P13 + P14 > P23 + P24 (indicating that the optical path length of the optical signal S1 from the fourth optical redirector 540 to the observer's second eye 60 is longer than the optical path length of the optical signal S2), the shape of the third optical redirector 530 is configured such that P11 + P12 < P21 + P22 (indicating that the optical path length of the optical signal S1 from the second optical projector 3 to the fourth optical redirector 540 is shorter than the optical path length of the optical signal S2). As a result, the total optical path length P11 + P12 + P13 + P14 of the optical signal S1 is approximately equal to the total optical path length P21 + P22 + P23 + P24 of the optical signal S2. Similarly, when P13 + P14 < P23 + P24, the shape of the third optical redirector 530 is configured such that P11 + P12 > P21 + P22.The geometric configuration of the optical elements described herein (including the third light redirector 530, the fourth light redirector 540, and the second combiner 40) may refer to the radius of curvature of the surfaces of the optical elements, the shape of the optical elements, the orientation of the major and minor axes of the optical elements, and / or the position of the optical elements. In certain instances, the shape of the optical elements may affect the focal position and other optical properties of the optical elements.

[0108] The above-described methods for removing distortion between edges of an image frame can also be used to reduce distortion from other regions of the image frame. In some embodiments, the shapes of the third light redirector 530, the fourth light redirector 540, and the second combiner 40 can be configured such that the total optical path length to the second eye 60 of a particular second-eye light signal, among the plurality of second-eye light signals emitted by the second light projector 3, that is not at the first and second spatial dimension limits is substantially equal to the total optical path length of the light signals emitted near the first and second spatial dimension limits.

[0109] For example, the surface of the third light redirector 530 receiving the plurality of second ocular light signals or the surface of the second combiner 40 receiving the plurality of second ocular light signals is an elliptical surface in this embodiment, so the surface may have at least two foci. In some embodiments, the surface of the third light redirector 530 receiving the plurality of second ocular light signals or the surface of the second combiner 40 receiving the plurality of second ocular light signals is an ellipsoid. In some embodiments, the surface of the third light redirector 530 receiving the plurality of second ocular light signals and the surface of the second combiner 40 receiving the plurality of second ocular light signals are both ellipsoids. In some embodiments, the surface of the third light redirector receiving the plurality of second ocular light signals or the surface of the second combiner receiving the plurality of second ocular light signals may be an aspheric surface or a freeform surface. The surface of the third light redirector 530 and the surface of the second combiner 40 may have different radii of curvature, i.e., the surfaces are portions of an ellipse with different major and / or minor axes. Although the third light redirector 530 and the second combiner 40 have different radii of curvature, in some embodiments, they can be integrated as a single optical element. The fourth light redirector 540 is a reflector that reflects a majority of the light (60% or more of the received light) in another direction. In other embodiments, the fourth light redirector 540 may be any reflective optical element that reflects a majority of the light (60% or more of the received light) in another direction (e.g., toward the second combiner 40). On the other hand, the third light redirector 530 or the second combiner 40 may allow ambient light to at least partially penetrate into the observer's eye (second eye 60). When the present invention is applied as a head-wearable display system or ARHWD, the fourth light redirector 540 is equivalent to a conventional combiner in an ARHWD and allows ambient light to pass through the fourth light redirector 540 and enter the observer's eye. Therefore, it is possible to create an augmented image that includes both virtual and real-world images.

[0110] For clarity, the following provides specifications for the third light redirector 530 and the second combiner 40. The diameters of the third light redirector 530 and the second combiner 40 may range from 10 mm to 40 mm, respectively. The distances from the center of the third light redirector 530 and the second combiner 40 to the first and second focal points may range from 10 mm to 20 mm and 20 mm to 30 mm, respectively. The distance between the center of the third light redirector 530 and the center of the second combiner 40 is between 25 mm and 40 mm. The maximum FOV of the image frame may be approximately 60 degrees, and in this embodiment, the appropriate eye relief (the shortest distance from the second combiner 40 to the observer's second eye 60) is approximately 15 mm to 30 mm.

[0111] Referring to FIG. 22 , this figure illustrates yet another embodiment of a head-wearable display system of the present invention. More specifically, unlike the head-wearable display system disclosed in FIG. 16 , the head-wearable display system illustrated in FIG. 22 further includes a light redirector. Note that although the head-wearable display system disclosed in FIG. 22 is a binocular head-wearable display system designed for a first eye 50 and a second eye 60 of an observer, in some embodiments, the head-wearable display system illustrated in FIG. 22 may be a monocular head-wearable display system that targets either the first eye 50 or the second eye 60 of the observer individually. Furthermore, for the first eye 50 of the observer, the head-wearable display system includes a first light projector 1 (which may include the aforementioned first light emitter, first collimator, first focusing element, and first light redirector), a first light redirector 510, a second light redirector 520, a first combiner 20, and the aforementioned target object detection module. Here, the configurations and functions of the first light projector 1, the first light redirector 510, the second light redirector 520, and the first combiner 20 are substantially the same as the configurations and functions of the second light projector 3, the third light redirector 530, the fourth light redirector 540, and the second combiner 40, so the details will not be repeated here.

[0112] To present a virtual image in three-dimensional space, the head-wearable display system of the present invention needs to be applied to both eyes of a viewer. Ideally, the head-wearable display systems for both eyes (first eye 50 and second eye 60) of the viewer should include the same optical elements. A method for presenting a virtual image in three-dimensional space will be described below with reference to FIG. 22 . The head-wearable display system of the present invention may further include a first light projector 1 for emitting a plurality of first-eye light signals. Each light signal of the plurality of first-eye light signals has a corresponding second-eye light signal from the plurality of second-eye light signals. More specifically, the viewer's eyes can view each light signal of the plurality of first-eye light signals together with the corresponding second-eye light signal, forming a binocular light signal through human visual fusion. As a result, the viewer perceives a single binocular light signal composed of a single first-eye light signal and its corresponding second-eye light signal. In this embodiment, the head-wearable display system further includes a first light redirector 510 and a first combiner 20. The first light redirector 510 is used to receive the plurality of first eye light signals and change the direction of each of the plurality of first eye light signals, while the first combiner 20 may receive the plurality of first eye light signals and change the direction of each of the plurality of first eye light signals as well as redirect and focus the plurality of first eye light signals to the first eye 50 of the observer. Similar to the third light redirector 530 and the second combiner 40, the first light redirector 510 receives the plurality of first eye light signals and directs the first eye light signals to the first combiner 20. The first combiner 20 directs the plurality of first eye light signals received from the first light redirector 510 to the other eye (first eye 50) of the observer and projects the plurality of first eye light signals onto the other retina of the observer. This allows the observer to see a first virtual image and a second virtual image, each composed of a plurality of first eye light signals and a plurality of second eye light signals, on the side of the second combiner 40 where the observer's eye is located and on the opposite side of the first combiner 20 where the observer's other eye is located. The head-wearable display system may further include a second light redirector 520 (equivalent to the aforementioned fourth light redirector 540) for receiving the plurality of first eye light signals and changing the direction of each of the plurality of first eye light signals.In this case, the first light redirector 510 receives a plurality of first eye light signals and directs the first eye light signals to the second light redirector 520, which then directs the plurality of first eye light signals received from the first light redirector 510 to the first combiner 20. The first combiner 20 directs the plurality of first eye light signals received from the second light redirector 520 to the other eye (first eye 50) of the observer. In this embodiment, the first light redirector 510 is equivalent to the third light redirector 530, the first combiner 20 is equivalent to the second combiner 40, and the second light redirector 520 is equivalent to the fourth light redirector 540.

[0113] The distortion correction performance of the present invention will now be described. As previously described, in some embodiments of the present invention, the image frame is substantially quadrilateral having a first edge, a second edge, a third edge, and a fourth edge, where the first edge and the third edge are composed of the same number of optical signals, and the second edge and the fourth edge are composed of the same number of optical signals. Referring to FIGS. 23A and 23B, for clarity, the present invention uses a rectangular image frame to demonstrate the performance of the head-wearable display system shown in FIG. 22. FIG. 23A illustrates the distortion correction performance of a conventional optical system without digital correction. The final image frame exhibits severe distortion in the vertical FOV (e.g., the second and fourth edges), resulting in a trapezoidal distortion of the image frame. The FOV ratio (equivalent to the length ratio) between the second and fourth edges is approximately 0.57. FIG. 23B illustrates the distortion correction performance of the head-wearable display system of the present invention shown in FIG. 22 (again without digital correction). The image frame retains the expected rectangular shape, and the FOV ratio (same as the ratio of lengths) between the second and fourth edges is close to 1. The FOV ratio (horizontal FOV) between the first and third edges is also close to 1. For clarity, the measured ratio of the FOV (or length) of the first edge to the FOV (or length) of the third edge is 0.95 to 1.05. Similarly, the ratio of the FOV (or length) of the second edge to the FOV (or length) of the fourth edge is also 0.95 to 1.05. It is clear that the present invention does not require digital distortion correction to correct small portions of the image frame. Therefore, by using the head-wearable display system of the present invention as shown in FIG. 22, the complete image information (in terms of resolution and number of pixels) of the image frame may be preserved. In addition to the FOV, the design of the present invention may improve the optical uniformity of the light intensity across the entire image frame.

[0114] Also, in some embodiments, the multiple first eye light signals emitted by the first light redirector of the first light projector 1 shown in FIG. 22 may be directed to the first light redirector 510 at a first eye incidence angle, which may be in a range of 15 degrees to 75 degrees. Furthermore, in some embodiments, the multiple second eye light signals emitted by the second light redirector of the second light projector 3 shown in FIG. 22 may be directed to the third light redirector 530 at a second eye incidence angle, which may also be in a range of 15 degrees to 75 degrees. Because the incidence angles (either the multiple first eye light signals or the multiple second eye light signals) of the multiple light signals (either the multiple first eye light signals or the multiple second eye light signals) emitted by the light redirector (either the first light redirector or the second light redirector) towards the redirector (either the first light redirector or the third light redirector) are different, the corresponding exit angles and focal lengths are also different. This results in different spot sizes of the light signals on the observer's retina (either the first or second eye). Specifically, if the light redirector emits the light signals toward the light redirector at a larger angle of incidence, the corresponding exit angle will be larger and the focal length will be longer, resulting in a larger spot size of the light signals on the retina; conversely, if the light redirector emits the light signals toward the light redirector at a smaller angle of incidence, the corresponding exit angle will be smaller and the focal length will be shorter, resulting in a smaller spot size of the light signals on the retina.

[0115] The present invention can capture real-time image pixels of a target object or surrounding environment and reproduce a three-dimensional digital image with enhanced image quality for the observer of the AR / VR system. The observer of the present invention can adjust the image quality to achieve better than normal VA (e.g., 20 / 20 vision or higher than VA 1.0). Furthermore, the present invention may provide vision correction for people with myopia, hyperopia, etc., to help people with visual impairments or as an alternative to traditional prescription glasses. The present invention can be used by medical professionals, military personnel, precision manufacturing industries, aerospace pilots, law enforcement, emergency rescue personnel, athletes, etc.

[0116] The description of the foregoing embodiments is provided to enable any person skilled in the art to make and use the subject matter. The methods described herein may be performed in any order. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the novel principles and subject matter disclosed herein may be applied to other embodiments without the exercise of innovative faculty. The claimed subject matter is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. Additional embodiments are contemplated within the spirit and true scope of the disclosed subject matter. Thus, it is intended that the present invention cover modifications and variations thereof within the scope of the appended claims and their equivalents.

Claims

1. a target object detection module that receives a plurality of image pixels of a first portion and a second portion of a target object and corresponding depths of the first portion and the second portion; a first light emitter that emits a plurality of first-eye light signals to display first-eye virtual images of the first and second portions of the target object to a viewer; a first light redirector configured to redirect the light direction of each of the plurality of first eye light signals emitted from the first light emitter; a first collimator disposed between the first light emitter and the first light redirector, the first collimator adjusting a beam waist position of each of the plurality of first eye light signals so that the plurality of first eye light signals can be separated from each other; a first focusing element disposed between the first collimator and the first light redirector, the first focusing element adjusting a beam waist size of each of the plurality of first eye light signals to adjust a spot size of the plurality of first eye light signals at a first eye of the observer; a first combiner that redirects and converges the plurality of first eye light signals toward the first eye of the observer; Head-wearable display system.

2. 2. The head-wearable display system of claim 1, wherein the first-eye virtual image of a first portion of the target object in a first field of view includes a greater amount of the first-eye light signal per degree than the first-eye virtual image of a second portion of the target object in a second field of view.

3. The head wearable display system of claim 1 , wherein the first focusing element has a radius of curvature between −5 mm and −50 mm.

4. The head-wearable display system of claim 1 , wherein the plurality of first eye light signals emitted by the first light redirector are emitted to a first combiner at a first eye light incidence angle between 15 degrees and 75 degrees.

5. a first light redirector for receiving the plurality of first eye light signals and redirecting the light of each of the plurality of first eye light signals; a second light redirector disposed adjacent a first focal point of the first light redirector and a first focal point of the first combiner, the second light redirector being a reflector; the first light redirector receives the plurality of first eye light signals and directs the plurality of first eye light signals to the first combiner, and the first combiner directs the plurality of first eye light signals received from the first light redirector to a first eye of the observer so that the observer can see a first image frame constituted by the plurality of first eye light signals; the first light redirector changes the projection directions of the plurality of first eye light signals in a first dimension between a first spatial dimension limit and a second spatial dimension limit; a geometric shape of the first light redirector configured to make a total optical path length from the first light redirector to a first eye of the observer in one of the plurality of first eye light signals emitted by the first light redirector near the first spatial dimension limit substantially equal to a total optical path length from the first light redirector to a first eye of the observer in another of the plurality of first eye light signals emitted by the first light redirector near the second spatial dimension limit; the first light redirector has two foci located in a space between the first light redirector and a first eye of the observer, the first focus of the first light redirector and the first focus of the first combiner being at the same spatial location; the first light redirector is adjacent to a second focal point of the first light redirector; a shortest distance from the first combiner to the first eye of the observer is 15 mm to 30 mm; The head-wearable display system of claim 1 .

6. 6. The head wearable display system of claim 5, wherein the plurality of first eye light signals emitted by the first light redirector are emitted to the first light redirector at a first eye light incidence angle, the first eye light incidence angle being between 15 degrees and 75 degrees.

7. 2. The head-wearable display system of claim 1, wherein the amount of distinguishable light signals per visual field unit projected onto the observer's retina is adjusted by changing the distance between the first light redirector and the first collimator.

8. 10. The head-wearable display system of claim 1, wherein the amount of distinguishable light signals per visual field unit projected onto the observer's retina is modulated by varying the distance between the first focusing element and the first light emitter.

9. a second light emitter that emits a plurality of second eye light signals corresponding to the plurality of first eye light signals to display a second eye virtual image of the first portion and the second portion of the target object to the observer; a second light redirector configured to redirect the light direction of each of the plurality of second eye light signals emitted from the second light emitter; a second collimator disposed between the second light emitter and the second light redirector, the second collimator adjusting a beam waist position of each of the plurality of second eye light signals so that the plurality of second eye light signals can be separated from each other; a second focusing element disposed between the second collimator and the second light redirector, the second focusing element adjusting a beam waist size of each of the second eye light signals to adjust a spot size of the second eye light signals at the second eye of the observer; a second combiner that redirects and converges the plurality of second-eye light signals toward the second eye of the observer; 2. The head-wearable display system of claim 1, wherein the first eye and the second eye perceive the plurality of first eye light signals and the plurality of second eye light signals to generate binocular vision, and one of the plurality of first eye light signals and a corresponding one of the plurality of second eye light signals form a binocular pixel having a first depth related to a convergence angle between an optical path extension of one of the plurality of first eye light signals and a corresponding one of the plurality of second eye light signals.

10. The head wearable display system of claim 9 , wherein the second focusing element has a radius of curvature between −5 mm and −50 mm.

11. The head-wearable display system of claim 9 , wherein the plurality of second eye light signals emitted by the second light redirector are emitted to the second combiner at a second eye light incidence angle between 15 degrees and 75 degrees.

12. a third light redirector for receiving the plurality of second eye light signals and redirecting the light of each of the plurality of second eye light signals; a fourth light redirector disposed adjacent a first focal point of the third light redirector and a first focal point of the second combiner, the fourth light redirector being a reflector; the third light redirector receives the plurality of second eye light signals and directs the plurality of second eye light signals to the second combiner, and the second combiner directs the plurality of second eye light signals received from the third light redirector to a second eye of the observer so that the observer can see a second image frame constituted by the plurality of second eye light signals; the second light redirector changes the projection directions of the plurality of second eye light signals in a second dimension between a third spatial dimension limit and a fourth spatial dimension limit; a geometric shape of the third light redirector configured to make a total optical path length from the second light redirector to the second eye of the observer in one of the plurality of second eye light signals emitted by the second light redirector near the third spatial dimension limit substantially equal to a total optical path length from the second light redirector to the second eye of the observer in another of the plurality of second eye light signals emitted by the second light redirector near the fourth spatial dimension limit; the third light redirector has two foci located in a space between the third light redirector and the second eye of the observer, and a first focus of the third light redirector and a first focus of the second combiner are at the same spatial location; the second light redirector is adjacent to a second focal point of the third light redirector; a shortest distance from the second combiner to the second eye of the observer is 15 mm to 30 mm; The head-wearable display system of claim 9 .

13. The head wearable display system of claim 12 , wherein the plurality of second eye light signals emitted by the second light redirector are emitted to the third light redirector at a second eye light incidence angle between 15 degrees and 75 degrees.

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