CN217639763U - Near-eye projection system and display device comprising same - Google Patents
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- CN217639763U CN217639763U CN202221632061.6U CN202221632061U CN217639763U CN 217639763 U CN217639763 U CN 217639763U CN 202221632061 U CN202221632061 U CN 202221632061U CN 217639763 U CN217639763 U CN 217639763U
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Abstract
The embodiment of the application provides a near-eye projection system and display equipment comprising the same, and relates to the technical field of display equipment. The near-eye projection system comprises: the device comprises an image generation module and a light modulation module; wherein the image generation module is configured to generate a plurality of discrete wavelengths of narrowband laser light at a plurality of time instants, respectively; the interval between any two adjacent moments in the multiple moments is less than the visual dwell time; the light modulation module comprises a first super lens, and the first super lens is a reflective multi-wavelength chromatic aberration correction super lens; the plurality of narrow-band lasers with discrete wavelengths are reflected by the first superlens and then enter the eye pupil. The present application facilitates the miniaturization of near-eye projection systems through reflective multi-wavelength chromatic aberration correction superlenses.
Description
Technical Field
The present application relates to the field of display devices, and in particular, to a near-eye projection system and a display device including the same.
Background
Virtual Reality (VR), augmented Reality (AR), and Mixed Reality (Mixed Reality) are today's leading-edge display technologies that improve the user's three-dimensional perception of image information through biased superimposition of projected images. Near-eye projection systems are a core component in VR/AR/MR display devices.
Existing near-eye projection systems include an image producing device and a multi-piece reflective aspherical mirror. The wide-spectrum light emitted by the image generating device through the plurality of reflection aspheric mirrors is continuously reflected and then emitted to the eye pupil.
However, as users pursue the miniaturization and weight reduction of VR/AR/MR display devices, the disadvantages of large volume and heavy weight of the multi-piece reflective aspherical mirror hinder the miniaturization and weight reduction of the near-eye projection system, thereby limiting the miniaturization and weight reduction of the VR/AR/MR display devices.
SUMMERY OF THE UTILITY MODEL
In order to solve the problem that the miniaturization of a near-eye projection system in the prior art is limited by a plurality of reflective aspheric mirrors, an embodiment of the present application provides a near-eye projection system, including:
the device comprises an image generation module and a light modulation module;
wherein the image generation module is configured to generate a plurality of discrete wavelength narrow band lasers at a plurality of time instants, respectively; the interval between any two adjacent moments in the multiple moments is less than the visual dwell time;
the light modulation module comprises a first super lens, and the first super lens is a reflective multi-wavelength chromatic aberration correction super lens; and also,
the plurality of narrow-band lasers with discrete wavelengths are reflected by the first superlens and then enter an eye pupil.
Optionally, the light modulation module further comprises a relay device;
the relay device is arranged between the image generation module and the first superlens on an optical path; the narrow-band laser generated by the image generation module is reflected or transmitted by the relay device and then is reflected to the eye pupil by the first superlens.
Optionally, the relay device is a second superlens;
the second super lens is a reflection type multi-wavelength chromatic aberration correction super lens; the second super lens reflects the narrow-band laser light generated by the image generation module to the first super lens; the first super lens reflects the narrow-band laser light reflected by the second super lens to the eye pupil.
Optionally, the relay device is a refractive lens;
the refraction lens refracts the narrow-band laser light generated by the image generation module to the first superlens; the first superlens reflects the narrow-band laser light refracted by the refractive lens to an eye pupil.
Optionally, the relay device is a mirror;
the reflector reflects the narrow-band laser light generated by the image generation module to the first superlens; the first super lens reflects the narrow-band laser light reflected by the reflector to an eye pupil.
Optionally, the relay device is a third superlens;
the third super lens is a transmission type multi-wavelength chromatic aberration correction super lens; the third super lens transmits the narrow-band laser light generated by the image generation module to the first super lens; the first superlens reflects the narrow-band laser light transmitted by the third superlens to an eye pupil.
Optionally, the image generation module includes a micro light emitting diode display array and a turntable filter;
the micro light-emitting diode display array is used for generating light with at least one color;
and the turntable filter is used for carrying out frequency selection on the light rays emitted by the micro light-emitting diode array.
Optionally, the image generation module includes at least two discrete lasers, at least two dichroic mirrors, a prism, and a digital micromirror device, which are sequentially arranged along the optical path;
the at least two dichroic mirrors are used for carrying out frequency selection and optical path turning on laser light generated by the at least two separated lasers;
the prism is used for distinguishing an illumination light path and a projection light path;
the digital micromirror device is used for modulating the light reflected by the prism according to the image to be projected.
Optionally, the image generation module comprises two blue lasers, a fluorescent disc, at least two dichroic mirrors, a prism and a digital micromirror device;
one of the two blue lasers is used for generating blue laser light, and the other of the two blue lasers is used for irradiating a fluorescent disc to generate at least two laser lights with different wavelengths from the blue laser light;
the at least two dichroic mirrors are used for carrying out frequency selection and light path turning on the blue laser and the at least two lasers;
the prism is used for distinguishing an illumination light path and a projection light path;
the digital micromirror device is used for modulating the light reflected by the prism according to the image to be projected.
Optionally, the image generation module includes at least two discrete narrow-band light emitting diodes, at least two dichroic mirrors, a prism, and a digital micromirror device, which are sequentially arranged along the optical path;
the at least two dichroic mirrors are used for carrying out frequency selection and light path turning on laser generated by the at least two separated narrow-band light-emitting diodes;
the prism is used for distinguishing an illumination light path and a projection light path;
the digital micromirror device is used for modulating the light reflected by the prism according to the image to be projected.
Optionally, any of the first superlens, the second superlens, or the third superlens includes a base layer and a nanostructure layer;
the nanostructure layer is disposed on one side of the substrate layer, and the nanostructure layer includes periodically arranged nanostructures.
Optionally, the nanostructures are periodically arranged in the form of superstructure units;
the superstructure unit is a close-packed graph, and the nano structure is arranged at the vertex and/or the center of the close-packed graph.
Optionally, the phase of the superlens at least satisfies:
wherein r is the center of the superlens to any nanostructureThe distance of the center; λ is the operating wavelength of the superlens,
for any phase associated with the operating wavelength, (x, y) are coordinates on the superlens, f ML Ai and bi are real coefficients for the focal length of the superlens.
Optionally, the nanostructure has an alignment period greater than or equal to 0.3 λ c and less than or equal to 2 λ c;
and λ c is the central wavelength of the working waveband of the superlens.
Optionally, the height of the nanostructures is greater than or equal to 0.3 λ c and less than or equal to 5 λ c;
and λ c is the central wavelength of the working waveband of the superlens.
Optionally, the shape of the nanostructure is a polarization insensitive structure.
Optionally, the shape of the nanostructure is a polarization insensitive structure.
Optionally, the nano structures are filled with fillers;
the extinction coefficient of the filler to the working wave band of the super lens is less than 0.01.
Optionally, the filler is a different material than the nanostructure; and,
the filler is of a different material than the base layer.
Optionally, the third superlens further comprises an antireflection film;
the antireflection film is arranged on one side, away from the nanostructure layer, of the substrate layer; or,
the antireflection film is arranged on one side of the nanostructure layer, which is adjacent to air.
An embodiment of the present application further provides a display device, which includes the near-eye projection system provided in any of the above embodiments.
According to the near-to-eye projection system and the display device comprising the same, the image generation module emits a plurality of discrete-wavelength narrow-band lasers at a plurality of moments, the first super lens of the light modulation module is used for realizing chromatic aberration correction of the plurality of discrete-wavelength narrow-band lasers, and the narrow-band lasers are reflected to the eye pupil. The first super lens provided by the embodiment of the application realizes the miniaturization and the light weight of a near-eye projection system, thereby promoting the miniaturization and the light weight of a display device.
Drawings
The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the application and, together with the description, serve to explain the principles of the application.
FIG. 1 illustrates an alternative schematic diagram of a near-eye projection system provided by an embodiment of the present application;
FIG. 2 illustrates yet another alternative schematic diagram of a near-eye projection system provided by an embodiment of the present application;
FIG. 3 is a schematic diagram illustrating an alternative configuration of a near-eye projection system provided by an embodiment of the present application;
FIG. 4 is a schematic diagram illustrating an alternative configuration of a near-eye projection system provided by an embodiment of the present application;
FIG. 5 is a schematic diagram illustrating yet another alternative configuration of a near-eye projection system provided by an embodiment of the present application;
FIG. 6 is a schematic diagram illustrating an alternative configuration of a near-eye projection system provided by an embodiment of the present application;
FIG. 7 is a schematic diagram illustrating an alternative configuration of a near-eye projection system provided by an embodiment of the present application;
FIG. 8 is a schematic diagram illustrating an alternative configuration of an image generation module of a near-eye projection system provided by an embodiment of the present application;
FIG. 9 is a schematic diagram illustrating an alternative configuration of an image generation module of a near-eye projection system according to an embodiment of the present application;
FIG. 10 is a schematic diagram illustrating an alternative configuration of an image generation module of a near-eye projection system according to an embodiment of the present disclosure;
FIG. 11 is a schematic diagram illustrating an alternative configuration of an image generation module of a near-eye projection system provided by an embodiment of the present application;
FIG. 12 is a schematic diagram illustrating an alternative arrangement of a superlens provided by an embodiment of the present application;
FIG. 13 illustrates an alternative perspective view of nanostructures in a superlens provided by embodiments of the present application;
FIG. 14 illustrates yet another alternative perspective view of nanostructures in a superlens provided by an embodiment of the present application;
FIG. 15 is a schematic diagram illustrating an alternative arrangement of nanostructures in a superlens provided by an embodiment of the present application;
FIG. 16 is a schematic diagram illustrating yet another alternative arrangement of nanostructures in a superlens provided by an embodiment of the present application;
FIG. 17 is a schematic diagram illustrating yet another alternative arrangement of nanostructures in a superlens provided by an embodiment of the present application;
FIG. 18 illustrates the transmittance of an alternative nanostructure of a superlens provided by embodiments of the present application;
FIG. 19 illustrates a phase diagram of an alternative nanostructure of a superlens provided by embodiments of the present application;
FIG. 20 illustrates transmittance of yet another alternative nanostructure of a superlens provided by an embodiment of the present application;
FIG. 21 illustrates a phase diagram of yet another alternative nanostructure of a superlens provided by an embodiment of the present application;
FIG. 22 shows the modulation transfer function at the 480nm band for the near-eye projection system shown in FIG. 7;
FIG. 23 shows the modulation transfer function at the 530nm band for the near-eye projection system shown in FIG. 7;
FIG. 24 shows the modulation transfer function at the 660nm band for the near-eye projection system shown in FIG. 7;
fig. 25 shows a distortion diagram for the near-eye projection system shown in fig. 7.
In the drawings, reference numerals denote:
1-an image generation module; 2-a light modulation module; 21-a relay device; 211-a base layer; 212-a nanostructure layer; 213-superstructure unit; 214-an anti-reflection film; 2121-nanostructures; 2122-filling.
Detailed Description
The present application will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments are shown. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Like numbers refer to like elements throughout. Also, in the drawings, the thickness, ratio and size of the components are exaggerated for clarity of illustration.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, "a," "an," "the," and "at least one" do not denote a limitation of quantity, but rather are intended to include both the singular and the plural, unless the context clearly dictates otherwise. For example, "a component" means the same as "at least one component" unless the context clearly dictates otherwise. "at least one of" should not be construed as limited to the quantity "one". "or" means "and/or". The term "and/or" includes any and all combinations of one or more of the associated listed items.
Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms defined in commonly used dictionaries should be interpreted as having the same meaning as is in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
The meaning of "comprising" or "comprises" indicates the property, quantity, step, operation, component, part or combination thereof, but does not exclude other properties, quantities, steps, operations, components, parts or combination thereof.
Embodiments are described herein with reference to cross-section illustrations that are idealized embodiments. Thus, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments described herein should not be construed as limited to the particular shapes of regions as illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, regions shown or described as flat may typically have rough and/or nonlinear features. Also, the acute angles shown may be rounded. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region and are not intended to limit the scope of the claims.
Hereinafter, exemplary embodiments according to the present application will be described with reference to the accompanying drawings. The prior art generally considers that the super lens can only be used for correcting monochromatic aberration, cannot be used for correcting phase difference of a wide spectrum, and therefore cannot be used for projecting a compound color image. Thus, for consumer electronics, superlenses cannot meet the demand for polychromatic projection for near-eye projection systems.
The embodiment of the present application provides a near-eye projection system, as shown in fig. 1 to 7, which includes an image generation module 1 and a light modulation module 2.
Fig. 1 illustrates the working principle of the near-eye projection system. Referring to fig. 1, the image generation module 1 is configured to generate a plurality of discrete wavelength narrow band lasers at a plurality of times, respectively. Any two adjacent time moments in the plurality of time moments are separated by less than the visual dwell time. The light modulation module 2 comprises a first super lens which is a reflection type multi-wavelength chromatic aberration correction super lens. Narrow-band lasers with a plurality of discrete wavelengths emitted by the image generation module 1 are reflected to the eye pupil after being subjected to aberration correction including chromatic aberration correction through the first superlens.
It should be noted that, the multi-wavelength chromatic aberration correction superlens provided in the embodiments of the present application enables the superlens to perform aberration correction including chromatic aberration on the narrow-band laser light with discrete wavelengths through phase design. Illustratively, a narrowband laser is a laser having a ratio of bandwidth to center wavelength of less than 0.1. Illustratively, a narrowband laser is a laser having a ratio of bandwidth to center wavelength of less than 0.03.
Note that, typically, the visual dwell time is less than 0.1 seconds. According to embodiments of the present application, the visual dwell time is related to a refresh rate of the near-eye projection system. For example, for a near-eye projection system with a refresh rate of 120Hz, the duration of each beam of light is 2.78 milliseconds. As another example, for a near-eye projection system with a refresh rate of 60Hz, the duration of each beam of light does not exceed 5.56 milliseconds.
It should be understood that the plurality of discrete wavelength narrow band lasers provided by the embodiments of the present application include at least two different wavelength narrow band lasers. Optionally, the plurality of discrete wavelength narrow band lasers includes at least three primary colors of red, green and blue.
Fig. 2 illustrates another implementation principle of a near-eye projection system provided by an embodiment of the present application. Referring to fig. 2, the light modulation module 2 further includes a relay device 21. The relay device 21 is disposed between the image generation module 1 and the first superlens on the optical path. After a plurality of beams of narrow-band lasers with discrete wavelengths emitted by the image generation module 1 in a time-sharing manner are reflected or transmitted by the relay device 21, chromatic aberration correction is performed by the first super lens and the lasers are reflected to the eye pupil. A in fig. 2 shows that the relay device 21 is of a reflective type, and b in fig. 2 shows that the relay device 21 is of a transmissive type.
According to an alternative embodiment of the present application, as shown in fig. 3, the relay device 21 is a second superlens. The second super lens is a reflection type multi-wavelength chromatic aberration correction super lens. The second super lens performs first aberration correction on the narrow-band laser emitted by the image generation module 1 and then reflects the narrow-band laser to the first super lens, and the first super lens performs second aberration correction on the received narrow-band laser and then reflects the narrow-band laser to an eye pupil. This configuration can advantageously reduce the size of the near-eye projection system in the optical transmission path.
According to an alternative embodiment of the present application, referring to fig. 4, the relay device 21 is a refractive lens. The refraction lens refracts the narrow-band laser generated by the image generation module 1 to the first super lens, and the first super lens reflects the received narrow-band laser to an eye pupil after correcting chromatic aberration. Therefore, the near-eye projection system utilizes the refraction lens to carry out chromatic aberration correction on the monochromatic light with any wavelength, thereby reducing the chromatic aberration correction pressure of the first super lens and reducing the chromatic aberration correction design difficulty of the first super lens. The refractive lens can perform not only chromatic aberration correction but also correction of aberrations including, but not limited to, spherical aberration, coma, curvature of field, astigmatism, distortion, and the like. It is understood that the refractive lens may be a spherical lens or an aspherical lens; the lens can be a glass lens or a plastic lens. Optionally, the refractive lens has a positive optical power.
According to an alternative embodiment of the present application, referring to fig. 5, the relay device 21 is a mirror. The reflector reflects the narrow-band laser generated by the image generation module 1 to the first super lens, and the first super lens reflects the received narrow-band laser to an eye pupil after correcting chromatic aberration. Therefore, the difficulty of chromatic aberration correction of the near-eye projection system provided by the embodiment of the application can be well reduced, and the volume of the near-eye projection system can be better reduced under some conditions.
According to an alternative embodiment of the present application, referring to fig. 6, the relay device 21 is a third superlens. The third super lens is a transmission type multi-wavelength chromatic aberration correction super lens. The third super lens transmits the narrow-band laser emitted by the image generation module 1 to the first super lens after performing first aberration correction, and the first super lens reflects the received narrow-band laser to the eye pupil after performing second aberration correction. This configuration is more advantageous for reducing the cost of near-eye projection systems.
It should be noted that, without being bound by any theory, when the relay device 21 is a transmissive optical element (including a superlens and a refractive lens), the relay device 21 not only corrects chromatic aberration of the incident light, but also corrects other aberrations (such as spherical aberration, coma aberration, curvature of field, astigmatism, distortion, etc.) besides chromatic aberration.
In an alternative embodiment, as shown in fig. 7 and 8, the image generation module 1 comprises a micro-led display array and a rotating disc filter; the micro light emitting diode display array is used for generating light with at least one color; the turntable filter is used for selecting the frequency of the light emitted by the micro light-emitting diode array.
In yet another alternative embodiment, as shown in fig. 9, the image generation module 1 includes at least two discrete lasers, at least two dichroic mirrors, a prism, and a Digital Micromirror Device (DMD), which are sequentially arranged along the optical path; the at least two dichroic mirrors are used for carrying out frequency selection and light path turning on laser generated by at least two separated lasers; the prism is used for distinguishing an illumination light path and a projection light path; the digital micromirror device is used to modulate light reflected by the prism according to an image to be projected.
In yet another alternative embodiment, as shown in fig. 10, the image generation module 1 includes at least two discrete lasers, at least two dichroic mirrors, a prism, and a digital micromirror device, which are sequentially arranged along the optical path; the at least two dichroic mirrors are used for carrying out frequency selection and light path turning on laser generated by at least two separated lasers; the prism is used for distinguishing an illumination light path and a projection light path; the digital micromirror device is used to modulate light reflected by the prism according to an image to be projected.
In yet another alternative embodiment, as shown in fig. 11, the image generation module 1 includes two blue lasers, a fluorescent disc, at least two dichroic mirrors, a prism, and a digital micromirror device;
one of the two blue lasers is used for generating blue laser light, and the other of the two blue lasers is used for irradiating the fluorescent disc to generate at least two laser lights with different wavelengths from the blue laser light; the two dichroic mirrors are used for carrying out frequency selection and light path turning on the blue laser and the at least two lasers; the prism is used for distinguishing an illumination light path and a projection light path; the digital micromirror device is used to modulate light reflected by the prism according to an image to be projected.
In yet another alternative embodiment, as shown in fig. 12, the image generation module 1 includes at least two discrete narrow-band light emitting diodes, at least two dichroic mirrors, a prism, and a digital micromirror device, which are sequentially arranged along the optical path; the at least two dichroic mirrors are used for carrying out frequency selection and light path turning on laser generated by the at least two separated narrow-band light-emitting diodes; the prism is used for distinguishing an illumination light path and a projection light path; the digital micromirror device is used to modulate light reflected by the prism according to an image to be projected.
It should be understood that the prism in any of the above embodiments can reflect the light beam emitted by the dichroic mirror to the digital micromirror device. The digital micromirror device outputs projection light by controlling the states of the micromirror units in different areas. The reflected light of the mirror in the on state in the digital micromirror device is transmitted from the prism to form a projected light. The reflected light from the mirror in the off state or transitional state in the dmd is reflected by the prism to avoid interfering with the projection light path. For example, the digital micromirror array modulates the ratio of different frequency beams passing through the prism according to the color of the image to be projected.
Any combination of the image generation module 1 and the light modulation module 2 provided in any of the above embodiments can be used.
The superlens provided by the embodiment of the present application is described in detail with reference to fig. 12 to 21.
The superlens is a specific application of a supersurface, which modulates the phase, amplitude and polarization of incident light by periodically arranged sub-wavelength-sized nanostructures. According to an embodiment of the present application, as shown in fig. 12, each of the first superlens, the second superlens, or the third superlens in the near-eye projection system provided by the embodiment of the present application includes a substrate layer 211 and a nanostructure layer 212; the nanostructure layer 212 is disposed on one side of the substrate layer 211, and the nanostructure layer 212 includes periodically arranged nanostructures 2121. In some cases, both sides of the base layer 211 are provided with the nanostructure layer 212.
In an alternative embodiment, the phase of the superlens in the optical system satisfies at least the following equation:
wherein r is the distance from the center of the superlens to the center of any nanostructure; lambda is the wavelength of operation and,
for any phase associated with the operating wavelength, x, y are the superlens mirror coordinates, f ML Is the focal length of the superlens. The phase of the superlens may be expressed by higher order polynomials, including even and odd polynomials. In the embodiment of the application, the equations (1), (2), (3), (7) and (8) can optimize the phase satisfying the even polynomial on the premise of not destroying the rotational symmetry of the super-surface phase. Compared with the formulas (1), (2), (3), (7) and (8), the formulas (4), (5) and (6) can optimize not only the phase satisfying even polynomial, but also the phase satisfying odd polynomial without destroying the rotational symmetry of the superlens phase, thereby remarkably improving the phase performance of the superlensThe optimization degree of freedom of the superlens is improved. It should be noted that the coefficient a in the above formula i And b i Positive or negative of (b) is related to the power of the superlens. For example, when the superlens has positive power, in the formulas (1), (2), (3), (7), (8), a 1 Less than zero; and in the formulae (4), (5) and (6), a 2 Less than zero.
Fig. 13 and 14 are perspective views illustrating a nanostructure of a superlens employed in a near-eye projection system provided by an embodiment of the present application. Optionally, as shown in fig. 13 or fig. 14, air or other materials transparent or translucent in the working wavelength band may be filled between the nanostructures on the superlens. According to embodiments of the present application, the absolute value of the difference between the refractive index of the filled material and the refractive index of the nanostructures should be greater than or equal to 0.5. As shown in fig. 13, the nanostructures may be polarization sensitive structures that impart a geometric phase to incident light. For example, an elliptic cylinder, a hollow elliptic cylinder, an elliptic hole shape, a hollow elliptic hole shape, a rectangular cylinder, a rectangular hole shape, a hollow rectangular cylinder, a hollow rectangular hole shape, and the like. As shown in fig. 14, the nanostructures may be polarization insensitive structures that impose a propagation phase on the incident light. For example, a cylindrical shape, a hollow cylindrical shape, a circular hole shape, a hollow circular hole shape, a square cylindrical shape, a square hole shape, a hollow square cylindrical shape, a hollow square hole shape, and the like.
According to the embodiment of the present application, as shown in fig. 15 to 17, the nanostructures 2121 are periodically arranged in the form of superstructure units 213, and the superstructure units 213 are a close-packable pattern provided with the nanostructures 2121 at the vertices and/or the central position thereof. As shown in fig. 15, superstructure units 213 may be arranged in a fan shape according to embodiments of the present application. As shown in fig. 16, according to an embodiment of the present application, superstructure units 213 may be arranged in an array of regular hexagons. Further, as shown in fig. 17, according to an embodiment of the present application, superstructure units 213 may be arranged in a square array. Those skilled in the art will recognize that the superstructure units included in the nanostructure layer may also include other forms of array arrangements, and all such variations are contemplated within the scope of the present application.
Optionally, superstructure unit 213 has a period greater than or equal to 0.3 λ c And is less than or equal to 2 lambda c (ii) a Wherein λ is c Is the center wavelength of the operating band; λ when the operating band is multiband c Is the center wavelength of the shortest wavelength operating band. Optionally, the height of the nanostructures is greater than or equal to 0.3 λ c And is less than or equal to 5 lambda c (ii) a Wherein λ is c Is the center wavelength of the operating band; λ when the operating band is multiband c Is the center wavelength of the shortest wavelength operating band. Alternatively, the periods of the superstructure units 213 at different positions on the superlens are the same. Optionally, the periods of superstructure units 213 at different positions on the superlens are at least partially the same.
According to an embodiment of the present application, the nanostructures 2121 are all-dielectric building units. The nanostructure 2121 is made of a material with high transmittance in the working band of the near-eye projection system. Optionally, the material of the nanostructures 2121 has an extinction coefficient to radiation in the operating band of less than 0.01. Illustratively, the material of the nanostructures 2121 includes one or more materials selected from fused quartz, quartz glass, crown glass, flint glass, sapphire, crystalline silicon, amorphous silicon, hydrogenated amorphous silicon, and the like.
In an alternative embodiment, the material of the substrate layer 211 is the same as the material of the nanostructures 2121. In yet another alternative embodiment, the material of the base layer 211 is different from the material of the nanostructures 2121. The base layer 211 is made of a material with high transmittance in the working wavelength band of the near-eye projection system provided in the embodiment of the present application. Optionally, the substrate layer 211 has an extinction coefficient of less than 0.01 for radiation in the operating band. Illustratively, the material of the substrate layer 211 may be one or more of fused silica, quartz glass, crown glass, flint glass, sapphire, crystalline silicon, amorphous silicon, hydrogenated amorphous silicon, and the like.
Illustratively, the superlens includes a silicon nitride nanostructure layer and a quartz glass substrate layer. The period of the superstructure unit is 400nm, the height of the nano structure is 1150nm, the shape of the nano structure is a nano cylinder, and the diameter of the nano structure is smaller than the period of the superstructure unit. FIG. 18 is a graph illustrating nanostructure size of an alternative superlens provided by embodiments of the present application as a function of transmittance of the superlens for different wavelength bands of incident light. FIG. 19 is a graph showing the relationship between the size of the nanostructure of an alternative superlens and the phase modulation of the superlens on different wavelength bands of incident light according to the embodiment of the present application.
Illustratively, the superlens includes a silicon nitride structure layer and a quartz glass substrate layer. The period of the superstructure unit is 400nm, the height of the nano structure is 1150nm, the nano structure is in the shape of a nano circular column, and the diameter of the nano structure is smaller than the period of the superstructure unit. FIG. 20 is a graph illustrating the nano-structure size of a super lens and the transmittance of the super lens for different wavelength bands of incident light according to still another alternative embodiment of the present application. FIG. 21 is a graph showing the relationship between the size of the nanostructure of another alternative superlens and the phase modulation of the superlens on different wavelength bands of incident light according to the embodiment of the present application.
According to the embodiment of the present application, the filler 2122 is a material with high transmittance in the working band, and optionally, the extinction coefficient of the material of the filler 2122 to the working band is less than 0.01. Illustratively, the material of the filler 2122 may be air. Illustratively, the material of the filler 2122 may be one or more of fused silica, quartz glass, crown glass, flint glass, sapphire, crystalline silicon, amorphous silicon, hydrogenated amorphous silicon, and the like. Preferably, the filler 2122 is a different material than both the base layer 211 material and the nanostructure 2121 material. Optionally, the absolute value of the difference in the refractive index of filler 2122 and the refractive index of nanostructure 2121 is greater than or equal to 0.5.
According to an embodiment of the present application, the third superlens further includes an anti-reflection film 214 for increasing transmittance of narrow-band light. The anti-reflection film 214 is disposed on one side of the substrate layer 211 and/or on one side of the nanostructure layer 212 adjacent to air.
Examples
An exemplary near-eye projection system provided by embodiments of the present application is shown in fig. 7. The main parameters of the near-eye projection system are shown in table 1. FIG. 22 shows the modulation transfer function of the near-eye projection system at the 480nm band. Fig. 23 shows the modulation transfer function of the near-eye projection system in the 530nm band. Fig. 24 shows the modulation transfer function of the near-eye projection system in the 660nm band. Fig. 25 shows a distortion diagram for the near-eye projection system. As can be seen from table 1 and fig. 22 to 25, the total system length of the near-eye projection system is 15mm, the modulation transfer functions at different wavelength bands are close to the diffraction limit, and the distortion is less than 5%. Therefore, the near-eye projection system is a compact near-eye projection system, and is good in imaging sharpness and excellent in distortion control.
TABLE 1
It should be noted that the superlens provided by the embodiments of the present application can be processed by a semiconductor process, and has the advantages of light weight, thin thickness, simple structure and process, low cost, high consistency of mass production, and the like.
An embodiment of the present application further provides a display device, which includes the near-eye projection system provided in any of the above embodiments.
In summary, the near-eye projection system and the display device including the same provided by the embodiment of the present application emit multiple beams of narrow-band laser with discrete wavelengths at multiple moments through the image generation module, implement chromatic aberration correction on the multiple beams of narrow-band laser with discrete wavelengths by using the first superlens of the light modulation module, and reflect the narrow-band laser to the eye pupil. The first super lens provided by the embodiment of the application realizes the miniaturization and the light weight of a near-eye projection system, thereby promoting the miniaturization and the light weight of a display device.
The above description is only a specific implementation of the embodiments of the present application, but the scope of the embodiments of the present application is not limited thereto, and any person skilled in the art can easily conceive of changes or substitutions within the technical scope of the embodiments disclosed in the present application, and all the changes or substitutions should be covered by the scope of the embodiments of the present application. Therefore, the protection scope of the embodiments of the present application shall be subject to the protection scope of the claims.
Claims (21)
1. A near-eye projection system is characterized by comprising an image generation module and a light modulation module;
wherein the image generation module is configured to generate a plurality of discrete wavelengths of narrowband laser light at a plurality of time instants, respectively; the interval between any two adjacent moments in the multiple moments is less than the visual dwell time;
the light modulation module comprises a first super lens, and the first super lens is a reflective multi-wavelength chromatic aberration correction super lens; and,
the plurality of narrow-band lasers with discrete wavelengths are reflected by the first super lens and then enter the eye pupil.
2. The near-eye projection system of claim 1, wherein the light modulation module further comprises a relay device;
the relay device is arranged between the image generation module and the first superlens on an optical path; the narrow-band laser generated by the image generation module is reflected or transmitted by the relay device and then reflected to the eye pupil by the first super lens.
3. The near-eye projection system of claim 2 wherein the relay device is a second superlens;
the second super lens is a reflective multi-wavelength chromatic aberration correction super lens; the second super lens reflects the narrow-band laser light generated by the image generation module to the first super lens; the first superlens reflects the narrow-band laser light reflected by the second superlens to an eye pupil.
4. The near-eye projection system of claim 2 wherein the relay device is a refractive lens;
the refraction lens refracts the narrow-band laser light generated by the image generation module to the first superlens; the first superlens reflects the narrow-band laser light refracted by the refractive lens to an eye pupil.
5. The near-eye projection system of claim 2 wherein the relay device is a mirror;
the reflector reflects the narrow-band laser light generated by the image generation module to the first superlens; the first super lens reflects the narrow-band laser light reflected by the reflector to an eye pupil.
6. The near-eye projection system of claim 2 wherein the relay device is a third superlens;
the third super lens is a transmission type multi-wavelength chromatic aberration correction super lens; the third super lens transmits the narrow-band laser light generated by the image generation module to the first super lens; the first superlens reflects the narrow-band laser light transmitted by the third superlens to an eye pupil.
7. The near-eye projection system of any of claims 1-6, wherein the image generation module comprises a micro-light emitting diode display array and a rotating disk filter;
the micro light-emitting diode display array is used for generating light with at least one color;
the turntable filter is used for selecting the frequency of the light emitted by the micro light-emitting diode array.
8. The near-eye projection system of any one of claims 1-6 wherein the image generation module comprises at least two discrete lasers, at least two dichroic mirrors, a prism, and a digital micromirror device arranged in sequence along an optical path;
the at least two dichroic mirrors are used for carrying out frequency selection and optical path turning on laser light generated by the at least two separated lasers;
the prism is used for distinguishing an illumination light path and a projection light path;
the digital micromirror device is used for modulating the light reflected by the prism according to the image to be projected.
9. The near-eye projection system of any of claims 1-6 wherein the image generation module comprises two blue lasers, a fluorescent disc, at least two dichroic mirrors, a prism, and a digital micromirror device;
one of the two blue lasers is used for generating blue laser light, and the other of the two blue lasers is used for irradiating a fluorescent disc to generate at least two laser light with different wavelengths from the blue laser light;
the at least two dichroic mirrors are used for carrying out frequency selection and light path turning on the blue laser and the at least two lasers;
the prism is used for distinguishing an illumination light path and a projection light path;
the digital micromirror device is used for modulating the light reflected by the prism according to the image to be projected.
10. The near-eye projection system of any one of claims 1-6 wherein the image generation module comprises at least two discrete narrow-band light emitting diodes, at least two dichroic mirrors, a prism, and a digital micromirror device arranged in sequence along the optical path;
the at least two dichroic mirrors are used for carrying out frequency selection and light path turning on laser generated by the at least two separated narrow-band light-emitting diodes;
the prism is used for distinguishing an illumination light path and a projection light path;
the digital micromirror device is used for modulating the light reflected by the prism according to an image to be projected.
11. The near-eye projection system of any of claims 1 or 3 or 6 wherein any of the first superlens or the second superlens or the third superlens comprises a substrate layer and a nanostructure layer;
the nanostructure layer is disposed on one side of the substrate, and the nanostructure layer includes periodically arranged nanostructures.
12. The near-eye projection system of claim 11 wherein the nanostructures are arranged periodically in the form of superstructure units;
the superstructure unit is a close-packed graph, and the nano structure is arranged at the vertex and/or the center of the close-packed graph.
13. The near-eye projection system of claim 11, wherein the phase of the superlens is at least:
wherein r is the distance from the center of the superlens to the center of any nanostructure; λ is the operating wavelength of the superlens,
for any phase associated with the operating wavelength, (x, y) are coordinates on the superlens, f ML Ai and bi are real coefficients for the focal length of the superlens.
14. The near-eye projection system of claim 11, wherein the nanostructures have an alignment period of greater than or equal to 0.3 λ c and less than or equal to 2 λ c;
and λ c is the central wavelength of the working waveband of the superlens.
15. The near-eye projection system of claim 11, wherein the height of the nanostructures is greater than or equal to 0.3 λ c and less than or equal to 5 λ c;
and λ c is the central wavelength of the working waveband of the superlens.
16. The near-eye projection system of claim 11, wherein the shape of the nanostructure is a polarization insensitive structure.
17. The near-eye projection system of claim 11, wherein the nanostructure is in the shape of a polarization-sensitive structure.
18. The near-eye projection system of claim 11, wherein the nanostructures are further filled with a filler;
the extinction coefficient of the filler to the working wave band of the super lens is less than 0.01.
19. The near-eye projection system of claim 18, wherein the filler is a different material than the nanostructure; and also,
the filler is of a different material than the base layer.
20. The near-eye projection system of claim 11, wherein the third superlens further comprises an antireflection film;
the antireflection film is arranged on one side, away from the nanostructure layer, of the substrate layer; or,
the antireflection film is arranged on one side of the nanostructure layer, which is adjacent to air.
21. A display device comprising the near-eye projection system of any one of claims 1-20.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11927769B2 (en) | 2022-03-31 | 2024-03-12 | Metalenz, Inc. | Polarization sorting metasurface microlens array device |
| US11978752B2 (en) | 2019-07-26 | 2024-05-07 | Metalenz, Inc. | Aperture-metasurface and hybrid refractive-metasurface imaging systems |
| US11988844B2 (en) | 2017-08-31 | 2024-05-21 | Metalenz, Inc. | Transmissive metasurface lens integration |
| WO2024152971A1 (en) * | 2023-01-18 | 2024-07-25 | Chiun Mai Communication Systems, Inc. | Metalens array and display device having same |
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2022
- 2022-06-28 CN CN202221632061.6U patent/CN217639763U/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11988844B2 (en) | 2017-08-31 | 2024-05-21 | Metalenz, Inc. | Transmissive metasurface lens integration |
| US11978752B2 (en) | 2019-07-26 | 2024-05-07 | Metalenz, Inc. | Aperture-metasurface and hybrid refractive-metasurface imaging systems |
| US11927769B2 (en) | 2022-03-31 | 2024-03-12 | Metalenz, Inc. | Polarization sorting metasurface microlens array device |
| WO2024152971A1 (en) * | 2023-01-18 | 2024-07-25 | Chiun Mai Communication Systems, Inc. | Metalens array and display device having same |
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