Near-eye display device

Abstract

The application provides a near-eye display device, which can realize extremely compact near-eye display light paths based on a fiber engine and a retinal projection imaging light path of a volume holographic grating, and helps to obtain a miniaturized near-eye display device so as to have a similar or completely similar glasses form. The near-eye display device comprises a device main body, a display lens, and a fiber engine. The display lens is arranged on the device main body, and the display lens is provided with a volume holographic grating. The fiber engine is correspondingly arranged on the device main body, and the fiber engine is used for projecting image light to the volume holographic grating of the display lens, so as to realize near-eye display by means of the volume holographic grating for redirecting reflection of the image light.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of near-eye display, in particular to a near-eye display device based on optical fiber. BACKGROUND

[0002] In recent years, the near-eye display (NED) technology such as augmented reality (AR) and virtual reality (VR) is increasingly popular. With the projection display becoming more and more miniaturized, the wearable near-eye display system is attracting more and more attention. People are not only pursuing small size and high resolution, but also increasingly demanding the wearing comfort.

[0003] At present, the core module of the conventional near-eye display device mainly consists of an optical engine module generating an image source and an expansion pupil into-eye module based on a diffractive optical waveguide. However, due to the large volume of the optical engine module, it is impossible to obtain a miniaturized near-eye display device no matter where the optical engine module is placed, such as on the temple or above the frame. Therefore, a practical solution is needed for the near-eye display device close to or completely in the form of glasses.

[0004] Although the 4f filter lens light path using traditional relay or the projection light path based on spatial light modulator and micro-electromechanical scanning system can realize the function of retinal imaging in a small space, on the one hand, the product of the exit pupil size and the field of view angle (i.e. the space bandwidth product) obtained by the projection light path based on SLM is limited due to the effective area and resolution of the spatial light modulator, and it is difficult to suppress the background light of the spatial light modulator; on the other hand, the space bandwidth product of the projection light path based on MEMS micro-mirror also has a certain upper limit, and the mass production of MEMS micro-mirror is very limited with high cost. SUMMARY

[0005] An advantage of the present application is to provide a near-eye display device which can realize a display device close to the form of glasses, facilitating comfortable wearing and promotion.

[0006] Another advantage of the present application is to provide a near-eye display device, wherein in one embodiment of the present application, the near-eye display device can realize an extremely compact near-eye display light path based on the retinal projection imaging light path of the optical fiber engine and the volume holographic grating, which helps to obtain a miniaturized near-eye display device to have a similar form close to or completely similar to glasses.

[0007] Another advantage of the present application is to provide a near-eye display device, wherein in an embodiment of the present application, the near-eye display device can employ a specially designed volume holographic grating to redirect image light to the human eye pupil, so that the redirected image light can be directly projected onto the retina, thereby realizing a compact and miniaturized near-eye display device.

[0008] Another advantage of the present application is to provide a near-eye display device, wherein in an embodiment of the present application, the near-eye display device can obtain a clear virtual-real fusion effect due to the perspective effect of the volume holographic grating on the real scene.

[0009] Another advantage of the present application is to provide a near-eye display device, wherein in an embodiment of the present application, the specially designed volume holographic grating employed by the near-eye display device has a pupil replication function to obtain a certain eyebox size to adapt to the interpupillary distance range of different wearers.

[0010] Another advantage of the present application is to provide a near-eye display device, wherein in an embodiment of the present application, the near-eye display device can solve the problem of field of view angle limitation based on the near-eye display light path of the fiber panel emitting spherical waves.

[0011] Another advantage of the present application is to provide a near-eye display device, wherein in an embodiment of the present application, the near-eye display device can suppress or eliminate stray light and stray light crosstalk between fiber arrays still existing in the traditional 4f filtering light path, thereby improving the display quality of the image.

[0012] Another advantage of the present application is to provide a near-eye display device, wherein in an embodiment of the present application, the near-eye display device can employ an asymmetric spherical wave fiber panel to solve the problem of image distortion, to ensure the fidelity of image projection.

[0013] Another advantage of the present application is to provide a near-eye display device, wherein in an embodiment of the present application, the near-eye display device can utilize fiber scanning to replace expensive MEMS micro-mirrors, which helps to reduce cost and size.

[0014] Another advantage of the present application is to provide a near-eye display device, wherein in an embodiment of the present application, the near-eye display device can employ a biased and asymmetrically distributed fiber scanning trajectory to correct image distortion, so as to obtain a normal image with equally spaced pixel distribution.

[0015] Another advantage of the present application is to provide a near-eye display device, wherein in order to achieve the above advantages, in the present application, there is no need to use expensive materials or complex structures. Therefore, the present application successfully and effectively provides a solution, not only to provide a simple near-eye display device, but also to increase the practicability and reliability of the near-eye display device.

[0016] Based on this, in order to achieve the above at least one advantage or other advantages and purposes of the present application, the present application provides a near-eye display device, comprising:

[0017] a device body;

[0018] a display lens, wherein the display lens is arranged on the device body, and the display lens is provided with a volume holographic grating; and

[0019] a fiber engine, wherein the fiber engine is correspondingly arranged on the device body, and the fiber engine is used to project image light to the volume holographic grating of the display lens to redirect and reflect the image light by the volume holographic grating for near-eye display.

[0020] According to an embodiment of the present application, the fiber engine is a fiber panel light engine, wherein the fiber panel light engine comprises a micro display, a first microlens array, a fiber panel, and a second microlens array, wherein the fiber panel is located between the first microlens array and the second microlens array to form a 4f relay lens, and the first microlens array is located between the micro display and the fiber panel.

[0021] According to an embodiment of the present application, the fiber panel light engine further comprises a linear polarizer and a narrowband filter, and the linear polarizer is correspondingly arranged between the second microlens array and the narrowband filter.

[0022] According to an embodiment of the present application, the fiber panel comprises a fiber array and a light-absorbing cladding, and the light-absorbing cladding is wrapped around each fiber in the fiber array.

[0023] According to an embodiment of the present application, the fiber engine is a fiber panel light engine, wherein the fiber panel light engine comprises a micro display, a first microlens array, a fiber panel, and a light deflector, wherein the fiber panel is located between the first microlens array and the light deflector to form a 4f relay lens, and the first microlens array is located between the micro display and the fiber panel.

[0024] According to an embodiment of the present application, the light deflector comprises a transparent substrate, a microlens unit and a Fresnel-like lens unit, wherein the microlens unit is arranged on the transparent substrate close to the side surface of the fiber faceplate, and the Fresnel-like lens unit is arranged on the transparent substrate away from the side surface of the fiber faceplate.

[0025] According to an embodiment of the present application, the spherical wave emitted by the fiber faceplate light engine presents an asymmetric light distribution relative to the center pixel of the micro display, and the light deflector is designed to make the emitted spherical wave equal in cross-sectional dimension relative to the center pixel on the surface of the volume holographic grating.

[0026] According to an embodiment of the present application, the fiber engine is a light scanning engine, wherein the fiber scanning engine comprises a laser module, a polarization maintaining fiber, an actuator and a collimator, wherein the leading end surface of the polarization maintaining fiber faces the laser module, and the trailing end surface of the polarization maintaining fiber faces the collimator, wherein the actuator is arranged at the trailing end of the polarization maintaining fiber for making the trailing end surface of the polarization maintaining fiber perform two-dimensional trajectory scanning.

[0027] According to an embodiment of the present application, the laser module comprises a laser emitter and a coupling lens, wherein the coupling lens is correspondingly arranged between the laser emitter and the leading end surface of the polarization maintaining fiber for converging the laser emitted by the laser emitter on the leading end surface of the polarization maintaining fiber to couple into the polarization maintaining fiber.

[0028] According to an embodiment of the present application, the scanning trajectory of the polarization maintaining fiber driven by the actuator in the fiber scanning light engine presents a biased asymmetric distribution.

[0029] According to an embodiment of the present application, the device body comprises a frame and a pair of legs, and the two legs are correspondingly arranged outside the frame, wherein the display lens is arranged on the frame, and the fiber engine is correspondingly arranged on the leg. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0031] Figure 1 The structural schematic diagram of the near-eye display device provided by an embodiment of the present application is shown in the figure;

[0032] Figure 2 Fig. 1 shows a schematic diagram of the working principle of the near-eye display device according to the above embodiment of the present application;

[0033] Figure 3 Fig. 2 shows a schematic diagram of the cross section of the fiber panel in the near-eye display device according to the above embodiment of the present application;

[0034] Figure 4 Fig. 3 shows a first variant example of the near-eye display device according to the above embodiment of the present application;

[0035] Figure 5 Fig. 4 shows a schematic diagram of the structure of the light deflector in the near-eye display device according to the above first variant example of the present application;

[0036] Figure 6 Fig. 5 shows a schematic diagram of the image distortion before correction in the near-eye display device according to the above first variant example of the present application;

[0037] Figure 7 Fig. 6 shows a schematic diagram of the spherical wave during image distortion correction in the near-eye display device according to the above first variant example of the present application;

[0038] Figure 8 Fig. 7 shows a schematic diagram of the light path after correction in the near-eye display device according to the above first variant example of the present application;

[0039] Figure 9 Fig. 8 shows a second variant example of the near-eye display device according to the above embodiment of the present application;

[0040] Figure 10A 10B Fig. 9 shows a schematic diagram of the scanning angle, scanning track and actuating signal of the near-eye display device according to the above second variant example of the present application before correction, respectively;

[0041] Figure 11A 11B Fig. 10 shows a schematic diagram of the scanning angle, scanning track and actuating signal of the near-eye display device according to the above second variant example of the present application after correction, respectively;

[0042] Figure 12A 12B Fig. 11 shows a schematic diagram of the forward distortion, reverse distortion and displayed image of the near-eye display device according to the above second variant example of the present application, respectively.

[0043] ​​​Reference numerals: 1, near-eye display device; 10, device main body; 100, eyeglass frame; 11, frame; 12, temple; 20, display lens; 200, volume holographic grating; 30, fiber engine; 31, fiber panel light engine; 311, micro display; 312, first microlens array; 313, fiber panel; 3131, fiber array; 3132, light absorbing cladding; 314, second microlens array; 315, linear polarizer; 316, narrow-band filter; 317, light deflector; 3171, transparent substrate; 3172, microlens unit; 3173, Fresnel-like lens unit; 32, fiber scanning light engine; 321, laser module; 3211, laser emitter; 3212, coupling lens; 322, polarization maintaining optical fiber; 3220, single-mode polarization maintaining optical fiber; 3221, leading end face; 3222, trailing end face; 323, actuator; 324, collimator. DETAILED DESCRIPTION

[0044] In order to make the above objectives, features and advantages of the present application more clear and easily understood, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. It will be apparent, however, to one skilled in the art that the present application can be practiced without using some or all of these specific details. In other instances, well-known process steps have not been described in detail in order to avoid obscuring the present application.

[0045] It is to be noted that when a component is referred to as being "on" or "disposed on" another component, it can be directly on the other component or there can be intervening components present. When a component is referred to as being "connected" to another component, it can be directly connected to the other component or there can be intervening components present. The terms "vertical", "horizontal", "up", "down", "left", "right", and similar expressions used in this specification are used for the purpose of illustration only and do not indicate the sole orientation of the implementation.

[0046] In addition, the terms "first", "second", etc. are used herein only to describe various tings and do not imply or connote relative importance or a number of indicated tings. Thus, features defined with "first", "second" can include at least one of the features, explicitly or implicitly. In the description of the present application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0047] In the present application, unless otherwise explicitly specified and limited, a first feature is "on", "under", "above" or "over" a second feature, which can mean that the first feature is in direct contact with the second feature, or the first feature is in indirect contact with the second feature through an intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can mean that the first feature is directly above or obliquely above the second feature, or only means that the first feature is horizontally higher than the second feature. The first feature "below", "under" and "underneath" the second feature can mean that the first feature is directly below or obliquely below the second feature, or only means that the first feature is horizontally lower than the second feature.

[0048] Unless otherwise defined, all technical and scientific terms used in the specification of the present application have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "and / or" used in the specification of the present application includes any and all combinations of one or more of the associated listed items.

[0049] Considering that the spatial bandwidth product obtained by the SLM-based projection light path and the MEMS micromirror-based projection light path has a certain upper limit, and the background light suppression of the spatial light modulator also has a certain difficulty, and the production scale of the MEMS micromirror is limited and the cost is high, therefore, the present application provides a near-eye display device, which can realize an extremely compact near-eye display light path based on the retinal projection imaging light path of the fiber engine and the volume holographic grating, which is helpful to obtain a miniaturized near-eye display device, so as to realize a display device in the form of approximate glasses, which is convenient for comfortable wearing and popularization.

[0050] Specifically, referring to the accompanying drawings Figures 1 to 3 One embodiment of the present application provides a near-eye display device 1, which can include a device main body 10, a display lens 20 and a fiber engine 30. The display lens 20 is arranged on the device main body 10, and the display lens 20 is provided with a volume holographic grating 200. The fiber engine 30 is correspondingly arranged on the device main body 10, and the fiber engine 30 is used to project image light to the volume holographic grating 200 of the display lens 20, so as to realize near-eye display by redirecting and reflecting the image light through the volume holographic grating 200.

[0051] It is worth noting that the near-eye display device 1 of the present application is a light path scheme based on the combination of the fiber engine and the volume holographic grating, that is, the image light (such as plane wave or spherical wave) emitted by the fiber engine 30 is redirected to the pupil of the human eye after being projected onto the display lens 20 by the specially designed volume holographic grating 200, so that the redirected image light is directly projected and imaged on the retina, thereby realizing a compact and miniaturized AR near-eye display device.

[0052] Optionally, the display lens 20 of the present application is made of transparent material. At the same time, since the volume holographic grating 200 has a perspective effect on the real scene, the near-eye display device 1 can obtain a clear virtual-real fusion image to make the user obtain an augmented reality experience, that is, the near-eye display device 1 of the present application can be implemented as an AR near-eye display device.

[0053] More specifically, as shown in the drawings, Figure 1 The device main body 10 of the near-eye display device 1 of the present application can be but not limited to be implemented as a spectacle frame 100, so that the near-eye display device 1 is implemented as AR glasses, which is convenient to wear. In other words, the device main body 10 of the present application can include a spectacle frame 11 and a pair of spectacle temples 12, and the two spectacle temples 12 are respectively arranged on the outer side of the spectacle frame 11, wherein the display lens 20 is arranged on the spectacle frame 11, and the optical fiber engine 30 is arranged on the spectacle temple 12 correspondingly, to form a near-eye display glasses, which is convenient for the user to wear comfortably.

[0054] It is worth noting that, although the device main body 10 is implemented as the spectacle frame 100 in the drawings Figure 1 and the above description, the features and advantages of the present application are described, but those skilled in the art can understand that the near-eye display device 1 disclosed in the drawings Figure 1 and the corresponding description is only an example, which does not constitute a limitation to the content and scope of the present application, for example, in other examples of the present application, the near-eye display device 1 can also include devices such as helmets or head-mounted supports and the like which are suitable to be worn on the head of the user, as long as it can ensure that the near-eye display can be realized, and the present application will not be described hereinafter.

[0055] According to the above embodiments of the present application, as Figure 2As shown, the fiber optic engine 30 of the near-eye display device 1 of this application can be implemented as a fiber optic panel light engine 31. The fiber optic panel light engine 31 may include a microdisplay 311, a first microlens array 312, a fiber optic panel 313, and a second microlens array 314. The fiber optic panel 313 is located between the first microlens array 312 and the second microlens array 314 to form a 4f relay lens, and the first microlens array 312 is located between the microdisplay 311 and the fiber optic panel 313. Thus, the emitted light from the microdisplay 311, after passing through the miniaturized 4f relay lens composed of the first microlens array 312, the fiber optic panel 313, and the second microlens array 314, generates a thin beam corresponding one-to-one with the pixels on the microdisplay 311. This allows the plane wave carrying image information (i.e., image light) to be projected onto the volume holographic grating 200 of the display lens 20, and then redirected by the volume holographic grating 200 to converge at the pupil of the human eye, directly forming an image on the retina.

[0056] It is understood that the near-eye display device 1 described in this application uses a 4f relay lens optical path based on a fiber optic panel to obtain an extremely compact optical engine; at the same time, the specially designed volume holographic grating in this application has the function of pupil replication in order to obtain a certain eye socket size to adapt to the interpupillary distance range of different wearers.

[0057] Optionally, such as Figure 2 As shown, the optical fiber panel optical engine 31 of this application may further include a linear polarizer 315 and a narrowband filter 316, wherein the linear polarizer 315 is correspondingly disposed between the second microlens array 314 and the narrowband filter 316, for filtering stray light in the image light emitted through the second microlens array 314, thereby improving the imaging quality of the image light.

[0058] It is worth noting that, in order to eliminate the stray light and stray crosstalk between fiber arrays that still exist in the traditional 4f filter optical path, such as Figure 3 As shown, the fiber optic panel 313 of this application may include a fiber optic array 3131 and a light-absorbing cladding 3132. The light-absorbing cladding 3132 covers each fiber in the fiber optic array 3131, allowing each fiber in the fiber optic array 3131 to transmit light independently, effectively suppressing stray light and thus producing a high-quality image. In other words, the light-absorbing cladding 3132 of this application fills the gaps between the fibers in the fiber optic array 3131, separating adjacent fibers in the fiber optic array 3131 and preventing stray light crosstalk, thus contributing to high-quality image light projection.

[0059] In addition, since the cross-sectional size D0 of the planar wave projected by the fiber panel light engine 31 of the present application is limited by the effective area of the micro display 311, the cross-sectional size D1 of the planar wave projected onto the surface of the volume holographic grating 200 is also limited. At the same time, since the near-eye display device 1 also imposes certain constraints on the distance L between the display lens 20 and the human eye, the field of view angle of the near-eye display light path based on the fiber panel exit planar wave is also limited.

[0060] To solve the problem of limited field of view angle, the fiber panel light engine 31 of the near-eye display device 1 according to the above-mentioned embodiments of the present application is replaced by a fiber panel light engine 31' in the first variant example of the present application. Figure 4 The first variant example of the near-eye display device 1 according to the present application is shown. Specifically, as shown in the first variant example of the present application, the fiber panel light engine 31 in the near-eye display device 1 is replaced by a light deflector 317 to make the fiber panel light engine 31 exit a spherical wave (i.e. image light), thereby forming a near-eye display light path of the exit spherical wave to solve the problem of limited field of view angle. Figure 4

[0061] More specifically, in the first variant example of the present application, as shown in the first variant example of the present application, the fiber panel light engine 31 can include the micro display 311, the first microlens array 312, the fiber panel 313, and the light deflector 317, wherein the fiber panel 313 is located between the first microlens array 312 and the light deflector 317 to form a 4f relay lens, and the first microlens array 312 is located between the micro display 311 and the fiber panel 313. In this way, the emitted light rays emitted by the micro display 311 will realize micro display exit spherical wave after passing through the miniaturized 4f relay lens composed of the first microlens array 312, the fiber panel 313, and the light deflector 317, at which time the arbitrary cross-sectional size D0 is obtained by the divergence angle θ0 of the spherical wave and the distance L1 from the convergence point F of the spherical wave to the surface of the volume holographic grating 200, and the near-eye display light path of arbitrary field of view angle can be realized. Figure 4

[0062] Optionally, as shown in the first variant example of the present application, the light deflector 317 can be a mirror, a prism, a holographic lens, or a combination thereof. Figure 5 ​​As shown, the light deflector 317 of the present application can include a transparent substrate 3171, a microlens unit 3172, and a Fresnel lens unit 3173, wherein the microlens unit 3172 is arranged on the transparent substrate 3171 close to the side surface of the fiber panel 313, and the Fresnel lens unit 3173 is arranged on the transparent substrate 3171 away from the side surface of the fiber panel 313, so as to realize the arbitrary exit angle of the pixels on the micro display 311 through the structure composed of the microlens unit 3172 and the Fresnel lens unit 3173.

[0063] It is worth noting that, as Figure 4 shown, when the symmetric spherical wave emitted by the fiber panel light engine 31 of the present application is obliquely incident on the surface of the volume holographic grating 200, the spherical wave will present an asymmetric distribution relative to the center of the surface, such as D1 Figure 4 , θ1 Figure 6 , and the like, which will further affect the fidelity of image projection.

[0064] In order to solve the problem of image distortion, the spherical wave emitted by the fiber panel light engine 31 of the present application needs to present an asymmetric light distribution relative to the center pixel of the micro display 311. Specifically, as Figure 7 and Figure 8 shown, the light deflector 317 in the fiber panel light engine 31 of the present application is specially designed so that the cross-sectional size of the emitted spherical wave on the surface of the volume holographic grating 200 relative to the center pixel is equal, i.e. D1=D2, and then the exit angles θ0, θ1, θ2 of the center pixel and the edge pixel of the light deflector 317 are determined, so that the exit angles of other offset pixels can be designed according to the equidistant sampling or arbitrary form interval sampling setting of the angle range (θ0, θ1) and (θ0, θ2), for example, θ0=arcsin(n*sinθ)-θ, thereby solving the problem of image distortion.

[0065] In other words, the light deflector 317 in the fiber panel light engine 31 of the present application is designed to make the cross-sectional size of the emitted spherical wave on the surface of the volume holographic grating 200 relative to the center pixel equal.

[0066] It is worth noting that although the near-eye display device 1 according to the above embodiments and the first variant example of the present application are both provided with the fiber panel light engine 31 as the fiber engine 30 to provide a miniaturized near-eye display light path based on a fiber panel, which is only an example; those skilled in the art can understand that in other examples of the present application, the near-eye display device 1 can also be provided with a fiber scanning light engine as the fiber engine 30 to provide a miniaturized near-eye display light path based on fiber scanning.

[0067] Exemplarily, in the second variant example of the present application, as shown in Figure 9 The fiber engine 30 of the near-eye display device 1 can be implemented as a fiber scanning light engine 32 to replace the expensive MEMS micromirror, which helps to reduce the cost. Specifically, the fiber scanning light engine 32 of the present application can include a laser module 321, a polarization maintaining optical fiber 322, an actuator 323, and a collimator 324, wherein the leading end face 3221 of the polarization maintaining optical fiber 322 faces the laser module 321, and the trailing end face 3222 of the polarization maintaining optical fiber 322 faces the collimator 324, wherein the actuator 323 is arranged at the trailing end of the polarization maintaining optical fiber 322 for making the trailing end face 3222 of the polarization maintaining optical fiber 322 perform two-dimensional trajectory scanning. In this way, the laser from the laser module 321 first enters the polarization maintaining optical fiber 322 from the leading end face 3221, and then exits from the trailing end face 3222 after transmission through the polarization maintaining optical fiber 322, at which time the actuator 323 arranged at a certain distance at the trailing end of the polarization maintaining optical fiber 322 makes the trailing end face 3222 of the polarization maintaining optical fiber 322 perform two-dimensional trajectory scanning to form a spherical wave exit; and then collimated by the collimator 324 and projected to the surface of the volume holographic grating 200 to realize retinal projection imaging.

[0068] Optionally, as shown in Figure 9 The laser module 321 of the present application can include a laser emitter 3211 and a coupling lens 3212, wherein the coupling lens 3212 is correspondingly arranged between the laser emitter 3211 and the leading end face 3221 of the polarization maintaining optical fiber 322, for converging the laser emitted by the laser emitter 3211 on the leading end face 3221 of the polarization maintaining optical fiber 322 to be coupled into the polarization maintaining optical fiber 322.

[0069] Optionally, as shown in Figure 9 The polarization maintaining optical fiber 322 of the present application can be but is not limited to a single-mode polarization maintaining optical fiber 3220.

[0070] Optionally, the collimator 324 of the present application can be implemented as, but not limited to, a lens, a ball lens, a Fresnel lens or a superlens, etc. It can be understood that the actuator 323 of the present application can enable the end face 3222 of the polarization maintaining fiber 322 to realize two-dimensional trajectory scanning to emit a spherical wave; and in order to realize retinal projection imaging, the light emitted by the end face 3222 of the polarization maintaining fiber 322 must be collimated light, i.e. a thin light beam, so the present application sets the collimator 324 at the end of the polarization maintaining fiber 322.

[0071] It is worth noting that when the symmetrical spherical wave scanned and emitted by the optical fiber is projected onto the surface of the volume holographic grating 200, the near-eye display device 1 of the present application also has the problem of image distortion. Specifically, as shown in FIG. 6, the image source corresponding to the symmetrical spherical wave presents an equal pixel spacing distribution, and the scanning trajectory driven by the actuator 323 also presents a symmetrical equal angle spacing distribution. The projection of the light generated by this actuation scanning mode on the surface of the volume holographic grating 200 presents an asymmetric distribution, i.e. as shown in FIG. 7, θ1=θ2 and D1=D2. Thus, the image after being redirected and reflected by the volume holographic grating 200 will inevitably have the distortion phenomenon as shown in FIG. 8. Figures 10A to 10C Figure 10A Figure 6

[0072] In order to correct the image distortion, the scanning trajectory of the polarization maintaining fiber 322 driven by the actuator 323 in the optical fiber scanning light engine 32 of the present application presents a biased asymmetric distribution. Specifically, as shown in FIG. 9, the biased position of the actuator 323 corresponds to the center pixel of the image, i.e. the light scanned by the actuator 323 of the present application presents an asymmetric distribution with respect to the light of the center pixel, i.e. θ1>θ2, which can be realized by the asymmetric duration and amplitude (t1, A1, t2, A2) of the actuation signal in one period to meet the requirement of D1=D2. At this time, if it is required that the pixels in the scanning angle range corresponding to θ1 and θ2 are the same, then the angular interval Δθ1>Δθ2, and the corresponding pixel interval Pitch1>Pitch2. Figures 11A to 11C

[0073] In summary, the un-biased symmetrical actuation mode introduces positive distortion to the image after being redirected and reflected by the volume holographic grating, as shown in FIG. 8; the biased asymmetric actuation mode introduces reverse distortion to the image itself, as shown in FIG. 10; and the image after being redirected and reflected by the volume holographic grating and received by the human eye can obtain a normal image with an equal pixel spacing distribution, as shown in FIG. 11. Figure 12A Figure 12B Figure 12C

[0074] ​​​​​​​The technical features of the above-described embodiments can be combined without changing the basic principles of the present application. For brevity, not all possible combinations of the technical features in the above-described embodiments are described, but it should be understood that any combination of the technical features is within the scope of the present disclosure as long as the combination does not result in contradictions.

[0075] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the patent application scope. It should be noted that, for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, and these are within the protection scope of the present application. Therefore, the patent protection scope of the present application should be subject to the appended claims.

Claims

1. A near-eye display device, characterized by, Comprising: a device body; a display mirror, wherein the display mirror is disposed on the device body, and the display mirror is provided with a volume holographic grating; the display mirror is made of transparent material; and a fiber engine, wherein the fiber engine is correspondingly disposed on the device body, and the fiber engine is used to project image light to the volume holographic grating of the display mirror to redirect the image light by the volume holographic grating for near-eye display; the fiber engine is a fiber panel light engine, wherein the fiber panel light engine includes a micro display, a first microlens array, a fiber panel, and a light deflector, wherein the fiber panel is located between the first microlens array and the light deflector to form a 4f relay lens, and the first microlens array is located between the micro display and the fiber panel; the light deflector includes a transparent substrate, a microlens unit, and a Fresnel lens unit, wherein the microlens unit is arranged on the side surface of the transparent substrate close to the fiber panel, and the Fresnel lens unit is arranged on the side surface of the transparent substrate away from the fiber panel.

2. The near-eye display device of claim 1, wherein, The spherical wave emitted by the fiber panel light engine presents an asymmetric light distribution relative to the center pixel of the micro display, and the light deflector is designed to make the emitted spherical wave equal in cross-sectional size relative to the center pixel on the surface of the volume holographic grating.

3. The near-eye display device of claim 1 or 2, wherein, The device body includes a frame and a pair of temples, and the two temples are correspondingly disposed on the outer side of the frame, respectively, wherein the display mirror is disposed on the frame, and the fiber engine is correspondingly disposed on the temples.

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