CN116643401A - Near-to-eye display device - Google Patents
Near-to-eye display device Download PDFInfo
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- CN116643401A CN116643401A CN202210137414.3A CN202210137414A CN116643401A CN 116643401 A CN116643401 A CN 116643401A CN 202210137414 A CN202210137414 A CN 202210137414A CN 116643401 A CN116643401 A CN 116643401A
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- 239000013307 optical fiber Substances 0.000 claims abstract description 69
- 230000010287 polarization Effects 0.000 claims description 36
- 230000003287 optical effect Effects 0.000 claims description 28
- 238000009826 distribution Methods 0.000 claims description 13
- 239000000758 substrate Substances 0.000 claims description 10
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- 238000003384 imaging method Methods 0.000 abstract description 7
- 210000001525 retina Anatomy 0.000 abstract description 6
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- 230000009286 beneficial effect Effects 0.000 abstract description 2
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- 238000007796 conventional method Methods 0.000 description 2
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- 238000011038 discontinuous diafiltration by volume reduction Methods 0.000 description 1
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Classifications
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/01—Head-up displays
- G02B27/017—Head mounted
- G02B27/0172—Head mounted characterised by optical features
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/01—Head-up displays
- G02B27/0101—Head-up displays characterised by optical features
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/01—Head-up displays
- G02B27/0101—Head-up displays characterised by optical features
- G02B2027/011—Head-up displays characterised by optical features comprising device for correcting geometrical aberrations, distortion
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/01—Head-up displays
- G02B27/0101—Head-up displays characterised by optical features
- G02B2027/0123—Head-up displays characterised by optical features comprising devices increasing the field of view
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/01—Head-up displays
- G02B27/017—Head mounted
- G02B27/0172—Head mounted characterised by optical features
- G02B2027/0174—Head mounted characterised by optical features holographic
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/01—Head-up displays
- G02B27/017—Head mounted
- G02B2027/0178—Eyeglass type
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
Abstract
The application provides a near-eye display device, which can realize an extremely compact near-eye display light path based on a fiber engine and a retina projection imaging light path of a volume holographic grating, and is beneficial to obtaining a miniaturized near-eye display device so as to have a near or completely similar glasses shape. The near-eye display device includes: an apparatus main body; a display lens, wherein the display lens is provided to the apparatus main body, and the display lens is provided with a volume hologram grating; and the optical fiber engine is correspondingly arranged on the equipment main body and is used for projecting image light to the volume holographic grating of the display lens so as to redirect and reflect the image light through the volume holographic grating to perform near-eye display.
Description
Technical Field
The application relates to the technical field of near-eye display, in particular to near-eye display equipment based on optical fibers.
Background
In recent years, near-to-eye display (NED) technologies such as Augmented Reality (AR) and Virtual Reality (VR) are increasingly hot. As projection displays tend to be miniaturized, wearable near-eye display systems are attracting attention, and people have higher and higher requirements for wearing comfort on the basis of pursuing small volume and high resolution.
Currently, the core module in a conventional near-eye display device mainly consists of an optical engine module for generating an image source and a pupil expansion and eye entrance module based on a diffraction optical waveguide. But is limited by the excessive volume of the optical engine module, resulting in that no miniaturized near-eye display device can be obtained, regardless of whether the optical engine module is placed over the temple or the frame, etc., and thus a viable solution is needed for near-eye display devices in a near-or full-eye form.
Although the function of retinal imaging can be realized in a smaller space by adopting a 4f filter lens optical path of a traditional relay or adopting a projection optical path based on a spatial light modulator and a micro-electromechanical scanning system, the method is limited by the effective area and the resolution of the spatial light modulator on one hand, the product (namely, the spatial bandwidth product) of the size of an exit pupil and the angle of view which can be obtained by adopting the projection optical path based on the SLM is limited, and meanwhile, the background light suppression of the spatial light modulator has a certain difficulty; on the other hand, the space bandwidth product of the projection light path based on the MEMS micro-mirror has a certain upper limit, and meanwhile, the mass production of the MEMS micro-mirror is very limited, and the cost is high.
Disclosure of Invention
An advantage of the present application is to provide a near-to-eye display device that can achieve a display device that approximates to a glasses form, facilitating comfortable wear and popularization.
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 is capable of realizing an extremely compact near-eye display light path based on a fiber optic engine and a retinal projection imaging light path of a volume hologram, contributing to a miniaturized near-eye display device so as to have a near or completely similar eye glass form.
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 is capable of redirecting image light to the pupil of a human eye using a specially designed volume holographic grating, so that the redirected image light can be directly projected and imaged onto the retina, thereby achieving a compact, miniaturized near-eye display device.
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 obtain a clear virtual-real fusion effect due to a perspective effect of a volume hologram grating on a real scene.
Another advantage of the present application is to provide a near-eye display device, wherein in one embodiment of the present application, a specially designed volume hologram grating used by the near-eye display device has a pupil replication function, so as to obtain a certain orbit size to adapt to the interpupillary range of different wearing people.
Another advantage of the present application is to provide a near-eye display device that, in one embodiment of the present application, can solve the problem of view angle limitation based on a near-eye display optical path of an outgoing spherical wave of an optical fiber panel.
Another advantage of the present application is to provide a near-eye display device, where in one embodiment of the present application, the near-eye display device can suppress or eliminate the problems of stray light still existing in the conventional 4f filtering optical path and stray light crosstalk between optical fiber arrays, so as to improve the display quality of an image.
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 solve the problem of image distortion using an asymmetric spherical wave fiber panel to ensure the fidelity of image projection.
Another advantage of the present application is to provide a near-eye display device that, in one embodiment of the present application, can utilize fiber scanning to replace expensive MEMS micromirrors, contributing to cost and volume reduction.
Another advantage of the present application is to provide a near-eye display device that, in one embodiment of the present application, is capable of correcting image distortion using offset and asymmetrically distributed fiber scan trajectories in order to obtain normal images of equidistant pixel distribution.
Another advantage of the present application is to provide a near-eye display device in which expensive materials or complex structures are not required in the present application in order to achieve the above advantages. The present application thus successfully and effectively provides a solution that not only provides a simple near-eye display device, but also increases the practicality and reliability of the near-eye display device.
To achieve at least one of the above or other advantages and objects of the application, there is provided a near-eye display device including:
an apparatus main body;
a display lens, wherein the display lens is provided to the apparatus body, and the display lens is provided with a volume hologram grating; and
and the optical fiber engine is correspondingly arranged on the equipment main body and is used for projecting image light to the volume holographic grating of the display lens so as to redirect and reflect the image light through the volume holographic grating to perform near-eye display.
According to one embodiment of the application, the fiber optic engine is a fiber optic panel light engine, wherein the fiber optic panel light engine comprises a micro-display, a first microlens array, a fiber optic panel, and a second microlens array, wherein the fiber optic panel is positioned between the first microlens array and the second microlens array to form a 4f relay lens, and the first microlens array is positioned between the micro-display and the fiber optic panel.
According to one embodiment of the application, the fiber panel light engine further comprises a linear polarizer and a narrowband filter, and the linear polarizer is disposed between the second microlens array and the narrowband filter, respectively.
According to one embodiment of the application, the fiber optic faceplate includes an array of optical fibers and a light absorbing cladding, and the light absorbing cladding is clad to each optical fiber in the array of optical fibers.
According to one embodiment of the application, the fiber optic engine is a fiber optic panel light engine, wherein the fiber optic panel light engine comprises a micro-display, a first microlens array, a fiber optic panel, and an optical deflector, wherein the fiber optic panel is positioned between the first microlens array and the optical deflector to form a 4f relay lens, and the first microlens array is positioned between the micro-display and the fiber optic panel.
According to one embodiment of the present application, the optical deflector includes a transparent substrate, a microlens unit, and a fresnel-like lens unit, wherein the microlens unit array is arranged on a side surface of the transparent substrate near the optical fiber panel, and the fresnel-like lens unit array is arranged on a side surface of the transparent substrate far from the optical fiber panel.
According to one embodiment of the application, the spherical wave emitted by the fiber optic panel light engine exhibits an asymmetric light distribution with respect to the central pixel of the micro-display, and the light deflector is designed to equalize the cross-sectional dimensions of the emitted spherical wave with respect to the central pixel on the surface of the volume hologram grating.
According to one embodiment of the application, the optical fiber engine is a light scanning engine, wherein the optical fiber scanning engine comprises a laser module, a polarization maintaining optical fiber, an actuator and a collimator, wherein a head end surface of the polarization maintaining optical fiber faces the laser module, and a tail end surface of the polarization maintaining optical fiber faces the collimator, wherein the actuator is arranged at the tail end of the polarization maintaining optical fiber and is used for enabling the tail end surface of the polarization maintaining optical fiber to perform two-dimensional track scanning.
According to one embodiment of the application, the laser module comprises a laser transmitter and a coupling lens, wherein the coupling lens is arranged between the laser transmitter and the head end face of the polarization maintaining fiber, respectively, for converging the laser transmitted via the laser transmitter to the head end face of the polarization maintaining fiber for coupling into the polarization maintaining fiber.
According to one embodiment of the application, the actuator in the optical fiber scanning light engine drives the scanning track of the polarization maintaining optical fiber to present an asymmetric distribution of bias.
According to an embodiment of the present application, the apparatus body includes a mirror frame and a pair of mirror legs, and both the mirror legs are respectively provided on the outside of the mirror frame, wherein the display lens is provided on the mirror frame, and the optical fiber engine is provided on the mirror leg.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments or the conventional techniques of the present application, the drawings required for the descriptions of the embodiments or the conventional techniques will be briefly described below, and it is apparent that the drawings in the following descriptions are only some embodiments of the present application, and other drawings may be obtained according to the drawings without inventive effort for those skilled in the art.
Fig. 1 is a schematic structural diagram of a near-eye display device according to an embodiment of the present application;
fig. 2 shows a schematic diagram of the working principle of the near-eye display device according to the above embodiment of the present application;
FIG. 3 shows a schematic cross-sectional view of a fiber optic faceplate in the near-eye display device according to the above-described embodiment of the application;
fig. 4 shows a first modified example of the near-eye display device according to the above embodiment of the present application;
fig. 5 shows a schematic structural view of an optical deflector in the near-eye display device according to the above-described first modification example of the present application;
fig. 6 shows a schematic view of image distortion of the near-eye display device before correction according to the above-described first modification example of the present application;
fig. 7 shows a spherical wave schematic diagram of the near-eye display device according to the above-described first modification example of the present application at the time of image distortion correction;
fig. 8 shows a schematic view of an optical path of the near-eye display device according to the above-described first modified example of the present application after correction;
fig. 9 shows a second modified example of the near-eye display device according to the above embodiment of the present application;
fig. 10A, 10B, and 10C are schematic diagrams showing a scanning angle, a scanning trajectory, and an actuation signal, respectively, of the near-eye display device according to the above-described second modified example of the present application before correction;
fig. 11A, 11B, and 11C are schematic diagrams showing a scanning angle, a scanning trajectory, and an actuation signal, respectively, of the near-eye display device according to the above-described second modified example of the present application after correction;
fig. 12A, 12B, and 12C show schematic diagrams of forward distortion, reverse distortion, and a displayed image of the near-eye display device according to the above-described second modified example of the present application, respectively.
Reference numerals: 1. a near-eye display device; 10. an apparatus main body; 100. a spectacle frame; 11. a frame; 12. a temple; 20. displaying the lens; 200. a volume holographic grating; 30. an optical fiber engine; 31. a fiber panel light engine; 311. a micro display; 312. a first microlens array; 313. an optical fiber panel; 3131. an optical fiber array; 3132. a light absorbing cladding; 314. a second microlens array; 315. a linear polarizer; 316. a narrow band filter; 317. an optical deflector; 3171. a transparent substrate; 3172. a microlens unit; 3173. a fresnel-like lens unit; 32. a fiber scanning light engine; 321. a laser module; 3211. a laser emitter; 3212. a coupling lens; 322. polarization maintaining optical fiber; 3220. a single mode polarization maintaining optical fiber; 3221. a head end surface; 3222. a distal end face; 323. an actuator; 324. a collimator.
Detailed Description
In order that the above objects, features and advantages of the application will be readily understood, a more particular description of the application will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. The present application may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the application, whereby the application is not limited to the specific embodiments disclosed below.
It will be understood that when an element is referred to as being "mounted" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. When a component is considered to be "connected" to another component, it can be directly connected to the other component or intervening components may also be present. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and the like are used in the description of the present application for the purpose of illustration only and do not represent the only embodiment.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present application, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.
In the present application, unless expressly stated or limited otherwise, a first feature "up" or "down" on a second feature may be that the first feature is in direct contact with the second feature, or that the first feature and the second feature are in indirect contact through intermedial media. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely under the second feature, or simply indicating that the first feature is less level than the second feature.
Unless defined otherwise, 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 this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and/or" as used in the description of the present application includes any and all combinations of one or more of the associated listed items.
Considering that the spatial bandwidth product obtained by the projection light path based on the SLM and the projection light path based on the MEMS micro-mirror has a certain upper limit, and the background light of the spatial light modulator is inhibited with a certain difficulty, the mass production scale of the MEMS micro-mirror is limited, and the cost is high, the application provides near-eye display equipment, which can realize an extremely compact near-eye display light path based on a fiber engine and a retina projection imaging light path of a volume holographic grating, is beneficial to obtaining a miniaturized near-eye display equipment so as to realize the display equipment similar to a glasses shape, and is convenient for comfortable wearing and popularization.
Referring to fig. 1 to 3, an embodiment of the present application provides a near-eye display device 1, which may include a device body 10, a display lens 20, and a fiber engine 30. The display lens 20 is provided to the apparatus body 10, and the display lens 20 is provided with a volume hologram 200. The optical fiber engine 30 is correspondingly disposed on the apparatus body 10, and the optical fiber engine 30 is configured to project image light to the volume hologram 200 of the display lens 20, so as to redirect and reflect the image light through the volume hologram 200 for near-eye display.
It should be noted that the near-eye display device 1 of the present application is a light path scheme based on a combination of an optical fiber engine and a volume hologram grating, that is, after the image light (such as a plane wave or a spherical wave) emitted from the optical fiber engine 30 is projected onto the display lens 20, the image light is redirected to the pupil of the human eye by using the specially designed volume hologram 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.
Alternatively, the display lens 20 of the present application is made of a transparent material. Meanwhile, since the volume hologram grating 200 has a perspective effect on a real scene, the near-eye display device 1 may obtain a clear virtual-real fusion image so that a user obtains an augmented reality experience, i.e., the near-eye display device 1 of the present application may be implemented as an AR near-eye display device.
More specifically, as shown in fig. 1, the device body 10 of the near-eye display device 1 of the present application may be implemented as, but is not limited to, a spectacle frame 100, so that the near-eye display device 1 is implemented as AR spectacles for easy wearing. In other words, the apparatus body 10 of the present application may include a frame 11 and a pair of temples 12, and the two temples 12 are respectively and correspondingly disposed at the outer sides of the frame 11, wherein the display lenses 20 are disposed at the frame 11, and the optical fiber engines 30 are correspondingly disposed at the temples 12 to form near-eye display glasses, so that the user can wear comfortably.
It should be noted that although in fig. 1 and the above description, the device body 10 is implemented as the spectacle frame 100 as an example, features and advantages of the present application are described, it will be understood by those skilled in the art that the near-eye display device 1 disclosed in fig. 1 and the corresponding description is only an example, and does not limit the content and scope of the present application, for example, in other examples of the present application, the near-eye display device 1 may also include a device suitable for being worn on the head of a user, such as a helmet or a head-wearing bracket, so long as the near-eye display can be ensured, which is not repeated herein.
According to the above-described embodiments of the present application, as shown in fig. 2, the optical fiber engine 30 of the near-eye display device 1 of the present application may be implemented as a fiber panel light engine 31, wherein the fiber panel light engine 31 may comprise a micro display 311, a first microlens array 312, a fiber panel 313, and a second microlens array 314, wherein the fiber 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 micro display 311 and the fiber panel 313. In this way, after passing through the miniaturized 4f relay lens composed of the first microlens array 312, the optical fiber panel 313 and the second microlens array 314, the emitted light beam emitted from the micro display 311 generates beamlets corresponding to pixels on the micro display 311 one by one, so that plane waves (i.e. image light) carrying image information are projected onto the volume hologram 200 of the display lens 20, and then redirected by the volume hologram 200 to converge at the pupil of human eye to be directly imaged on the retina.
It will be appreciated that the near-eye display device 1 of the present application can achieve an extremely compact optical engine using such a 4f relay lens optical path based on a fiber optic panel; meanwhile, the volume holographic grating with special design has the function of pupil replication, so that a certain orbit size is obtained to adapt to the interpupillary distance range of different wearing groups.
Optionally, as shown in fig. 2, the optical fiber panel light engine 31 of the present application may further include a linear polarizer 315 and a narrowband filter 316, where 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, so as to improve the imaging quality of the image light.
It should be noted that, in order to eliminate the problems of stray light and stray light crosstalk between fiber arrays in the conventional 4f filtering optical path, as shown in fig. 3, the fiber panel 313 of the present application may include a fiber array 3131 and a light-absorbing cladding 3132, where the light-absorbing cladding 3132 wraps each fiber in the fiber array 3131, so that each fiber in the fiber array 3131 transmits light independently, so as to effectively suppress stray light and further generate a high-quality image. In other words, the light-absorbing cladding 3132 of the present application fills the optical fiber gap of the optical fiber array 3131, so that adjacent optical fibers in the optical fiber array 3131 are separated by the light-absorbing cladding 3132, preventing the occurrence of stray light crosstalk, and contributing to obtaining high-quality image light projection.
Furthermore, due to the cross-sectional dimension D of the plane wave projected by the fiber optic panel light engine 31 of the present application 0 Will be limited by the effective area of the micro display 311 and therefore the cross-sectional dimension D projected onto the surface of the volume hologram 200 1 There will be certain limitations. Meanwhile, since the near-eye display device 1 also puts a certain constraint requirement on the distance L from the display lens 20 to the human eye, there is a certain limit on the angle of view that can be obtained based on the near-eye display light path of the plane wave emitted from the optical fiber panel.
In order to solve the problem that the angle of view is limited, fig. 4 shows a first modified example of the near-eye display device 1 according to the above-described embodiment of the present application. Specifically, as shown in fig. 4, the optical fiber panel light engine 31 in the near-eye display device 1 according to the first modified example of the present application replaces the above-described second microlens array 314 with the light deflector 317 to cause the optical fiber panel light engine 31 to emit spherical waves (i.e., image light), thereby forming a near-eye display light path of the emitted spherical waves to solve the problem of limitation of the angle of view.
More specifically, in a first modified example of the present application, as shown in fig. 4, the optical fiber panel light engine 31 may include the micro display 311, the first microlens array 312, the optical fiber panel 313, and the light deflector 317, wherein the optical 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 optical fiber panel 313. In this way, the emitted light beam emitted through the micro display 311 passes through the miniaturized 4f relay lens composed of the first micro lens array 312, the optical fiber panel 313 and the optical deflector 317 to realize the emission of spherical waves from the micro display, and then passes through the divergence angle θ of the spherical waves 0 And the distance L from the convergence point F of the spherical wave to the surface of the volume hologram grating 200 1 To obtain an arbitrary cross-sectional dimension D 0 And then a near-to-eye display light path with any angle of view can be realized.
Alternatively, as shown in fig. 5, the optical deflector 317 of the present application may include a transparent substrate 3171, a microlens unit 3172, and a fresnel-like lens unit 3173, wherein the microlens unit 3172 is arrayed on the transparent substrate 3171 near a side surface of the optical fiber panel 313, and the fresnel-like lens unit 3173 is arrayed on the transparent substrate 3171 far from the side surface of the optical fiber panel 313, so that an arbitrary exit angle of pixels on the micro display 311 is realized by a structure composed of the microlens unit 3172 and the fresnel-like lens unit 3173.
It should be noted that, as shown in fig. 4, when the symmetrical spherical wave emitted from the optical engine 31 of the fiber panel of the present application is obliquely incident to the surface of the volume hologram 200, the spherical wave exhibits an asymmetric distribution, such as D, with respect to the center of the surface 1 ＜D 2 When the volume hologram 200 is prepared by spherical wave exposure with a symmetrical surface center, the image light incident obliquely will have distortion problem when being redirected and reflected by the volume hologram 200 and received by the retina of human eyes, i.e. the image will have pixel shift, as shown by the center dotted line of fig. 4, θ 1 ＜θ 2 The method comprises the steps of carrying out a first treatment on the surface of the Or the compression and expansion of local pixels as shown in fig. 6, thereby affecting the fidelity of the image projection.
To solve the problem of image distortion, the spherical wave emitted by the optical fiber panel light engine 31 of the present application needs to exhibit asymmetric light distribution with respect to the central pixel of the micro-display 311. Specifically, as shown in fig. 7 and 8, the optical deflector 317 in the optical fiber panel optical engine 31 of the present application is designed so that the outgoing spherical wave has the same cross-sectional dimension with respect to the center pixel on the surface of the volume hologram 200, i.e., D 1 ＝D 2 Thereby determining the exit angle θ of the center pixel and the edge pixel of the optical deflector 317 0 、θ 1 、θ 2 Such that the exit angles of other offset pixels can be determined according to the angle range (θ 0 ，θ 1 ) Sum (theta) 0 ，θ 2 ) Arrangements for equidistant sampling or arbitrary form of equidistant sampling are envisaged, e.g. θ 0 =arcsin (n×sin θ) - θ, thereby solving the problem of image distortion.
In other words, the optical deflector 317 in the fiber-panel light engine 31 of the present application is designed to equalize the cross-sectional size of outgoing spherical waves with respect to a center pixel on the surface of the volume hologram grating 200.
It is to be noted that, although the near-eye display device 1 according to the above-described embodiment and the first modified example of the present application has the optical fiber panel light engine 31 as the optical fiber engine 30 to provide a miniaturized near-eye display light path based on an optical fiber panel, it is merely an example; it will be appreciated by those skilled in the art that in other examples of the application, the near-eye display device 1 may also function as the fiber engine 30 with a fiber scanning light engine to provide a miniaturized near-eye display light path based on fiber scanning.
Illustratively, in a second modified example of the present application, as shown in fig. 9, the optical fiber engine 30 of the near-eye display device 1 may be implemented as a fiber scanning light engine 32 to replace expensive MEMS micromirrors, contributing to cost reduction. Specifically, the optical fiber scanning optical engine 32 of the present application may include a laser module 321, a polarization maintaining fiber 322, an actuator 323, and a collimator 324, where a front end face 3221 of the polarization maintaining fiber 322 faces the laser module 321, and an end face 3222 of the polarization maintaining fiber 322 faces the collimator 324, where the actuator 323 is disposed at an end of the polarization maintaining fiber 322, for performing two-dimensional track scanning on the end face 3222 of the polarization maintaining fiber 322. Thus, the laser light from the laser module 321 enters the polarization maintaining fiber 322 from the front end face 3221, and then exits from the end face 3222 after being transmitted through the polarization maintaining fiber 322, and at this time, the actuator 323 disposed at a certain distance from the end of the polarization maintaining fiber 322 causes the end face 3222 of the polarization maintaining fiber 322 to perform two-dimensional trajectory scanning, so as to form spherical wave exit; and then collimated by the collimator 324, and projected onto the surface of the volume hologram 200 to realize retinal projection imaging.
Alternatively, as shown in fig. 9, the laser module 321 of the present application may include a laser emitter 3211 and a coupling lens 3212, where the coupling lens 3212 is disposed between the laser emitter 3211 and the front end face 3221 of the polarization maintaining fiber 322, respectively, for converging laser light emitted via the laser emitter 3211 to the front end face 3221 of the polarization maintaining fiber 322 to couple into the polarization maintaining fiber 322.
Alternatively, as shown in FIG. 9, the polarization maintaining fiber 322 of the present application may be implemented as, but is not limited to, a single mode polarization maintaining fiber 3220.
Alternatively, the collimator 324 of the present application may be implemented as, but is not limited to, a lens, a ball lens, a fresnel lens, a superlens, or the like. It is appreciated that the actuator 323 of the present application enables the end face 3222 of the polarization maintaining fiber 322 to perform a two-dimensional trajectory scan to emit spherical waves; in order to realize the retinal projection imaging, the light emitted from the end face 3222 of the polarization-preserving fiber 322 must be collimated light, i.e. a beamlet, so the collimator 324 is disposed at the end of the polarization-preserving fiber 322.
It should be noted that, when the symmetrical spherical wave emitted by the optical fiber scanning is projected onto the surface of the volume hologram grating 200, the near-eye display device 1 of the present application also has a problem of image distortion. Specifically, as shown in fig. 10A to 10C, the image source corresponding to the symmetrical spherical wave has an equal pixel pitch distribution, and the scanning track driven by the actuator 323 also has a symmetrical equal angular pitch distribution, and the projection of the light generated by the scanning manner on the surface of the volume hologram 200 will have an asymmetric distribution, that is, θ as shown in fig. 10A 1 ＝θ 2 And D 1 ＝D 2 The image thus redirected by the volume hologram 200 must have distortion as shown in fig. 6.
To correct for image distortion, the actuator 323 in the fiber scanning light engine 32 of the present application drives the scan trajectory of the polarization maintaining fiber 322 to exhibit an offset asymmetric distribution. Specifically, as shown in fig. 11A to 11C, the offset position of the actuator 323 corresponds to the center pixel of the image, that is, the light scanned by the actuator 323 of the present application has an asymmetric distribution, such as θ, with respect to the light of the center pixel 1 ＞θ 2 Which can be controlled by the actuation signal for a period of asymmetric duration and amplitude (t 1 ，A 1 ，t 2 ，A 2 ) To realize D 1 ＝D 2 Is not limited. At this time if required theta 1 And theta 2 The corresponding scan angle range has the same pixels, and the angle interval delta theta is then 1 ＞Δθ 2 Corresponding pixel intervals Pitch1 > Pitch2.
In summary, in the actuation mode without offset symmetry, the image distortion introduced by the image generated by scanning through the redirecting reflection of the volume hologram grating is forward distortion, as shown in fig. 12A; by applying an asymmetric actuating mode of bias, the image generated by scanning has certain distortion which is reverse distortion, as shown in fig. 12B; and the image received by human eyes after the reverse distortion image is redirected and reflected by the volume holographic grating can obtain a normal image with equidistant pixel distribution, as shown in fig. 12C.
The technical features of the above-described embodiments may be combined without changing the basic principle of the present application, and for brevity of description, all possible combinations of the technical features of the above-described embodiments are not described, however, as long as there is no contradiction between the combinations of the technical features, they should be regarded as the scope of the description of the present specification.
The above examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the claims. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of the application should be determined from the following claims.
Claims (11)
1. A near-eye display device, comprising:
an apparatus main body;
a display lens, wherein the display lens is provided to the apparatus body, and the display lens is provided with a volume hologram grating; and
and the optical fiber engine is correspondingly arranged on the equipment main body and is used for projecting image light to the volume holographic grating of the display lens so as to redirect and reflect the image light through the volume holographic grating to perform near-eye display.
2. The near-eye display device of claim 1, wherein the fiber optic engine is a fiber optic panel light engine, wherein the fiber optic panel light engine comprises a micro-display, a first microlens array, a fiber optic panel, and a second microlens array, wherein the fiber optic panel is positioned between the first microlens array and the second microlens array to form a 4f relay lens, and the first microlens array is positioned between the micro-display and the fiber optic panel.
3. The near-eye display device of claim 2, wherein the fiber panel light engine further comprises a linear polarizer and a narrowband filter, and the linear polarizer is disposed between the second microlens array and the narrowband filter, respectively.
4. A near-eye display device as claimed in claim 3, wherein the fiber optic faceplate comprises an array of optical fibers and a light absorbing cladding, and the light absorbing cladding is clad to each optical fiber in the array of optical fibers.
5. The near-eye display device of claim 1, wherein the fiber optic engine is a fiber optic panel light engine, wherein the fiber optic panel light engine comprises a micro-display, a first microlens array, a fiber optic panel, and an optical deflector, wherein the fiber optic panel is positioned between the first microlens array and the optical deflector to form a 4f relay lens, and the first microlens array is positioned between the micro-display and the fiber optic panel.
6. The near-eye display device of claim 5, wherein the light deflector comprises a transparent substrate, a microlens unit, and a fresnel-like lens unit, wherein the microlens unit array is arranged on a side surface of the transparent substrate near the optical fiber panel, and the fresnel-like lens unit array is arranged on a side surface of the transparent substrate remote from the optical fiber panel.
7. The near-eye display device of claim 6, wherein the spherical wave emitted by the fiber optic panel light engine exhibits an asymmetric light distribution with respect to a center pixel of the micro-display, and the light deflector is designed to equalize the cross-sectional dimensions of the emitted spherical wave with respect to the center pixel on the surface of the volume hologram grating.
8. The near-eye display device of claim 1, wherein the optical fiber engine is a light scanning engine, wherein the optical fiber scanning engine comprises a laser module, a polarization maintaining optical fiber, an actuator, and a collimator, wherein a front end surface of the polarization maintaining optical fiber faces the laser module, and a rear end surface of the polarization maintaining optical fiber faces the collimator, wherein the actuator is disposed at a rear end of the polarization maintaining optical fiber for two-dimensional trajectory scanning of the rear end surface of the polarization maintaining optical fiber.
9. The near-eye display device of claim 8, wherein the laser module comprises a laser emitter and a coupling lens, wherein the coupling lens is disposed between the laser emitter and the head end face of the polarization maintaining fiber, respectively, for converging laser light emitted via the laser emitter at the head end face of the polarization maintaining fiber for coupling into the polarization maintaining fiber.
10. The near-eye display device of claim 9, wherein the actuator in the fiber scanning light engine drives the scan trajectory of the polarization maintaining fiber to exhibit an offset asymmetric distribution.
11. The near-eye display device of any one of claims 1 to 10, wherein the device body includes a mirror frame and a pair of mirror legs, and both of the mirror legs are respectively provided on an outer side of the mirror frame, wherein the display lens is provided on the mirror frame, and the optical fiber engine is provided on the mirror leg, respectively.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210137414.3A CN116643401A (en) | 2022-02-15 | 2022-02-15 | Near-to-eye display device |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210137414.3A CN116643401A (en) | 2022-02-15 | 2022-02-15 | Near-to-eye display device |
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| CN116643401A true CN116643401A (en) | 2023-08-25 |
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| CN202210137414.3A Pending CN116643401A (en) | 2022-02-15 | 2022-02-15 | Near-to-eye display device |
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Application publication date: 20230825 Assignee: Zhejiang Shunwei Technology Co.,Ltd. Assignor: SUNNY OPTICAL (ZHEJIANG) RESEARCH INSTITUTE Co.,Ltd. Contract record no.: X2024330000055 Denomination of invention: Near eye display devices License type: Common License Record date: 20240515 |
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