CN116299836A - Transparent display based on AR optical waveguide technology - Google Patents

Abstract

The invention discloses a transparent display based on AR optical waveguide technology, which comprises an optical waveguide assembly, an optical engine and a frame; the optical waveguide assembly and the optical engine are both arranged in the frame; the optical waveguide assembly includes a grating unit including: the optical engine comprises an entrance pupil grating unit, a pupil expansion grating unit and an exit pupil grating unit which are respectively used for forming an entrance pupil area, a pupil expansion area and an exit pupil area, wherein light rays coupled out of the optical engine are sequentially transmitted in the entrance pupil area, the pupil expansion area and the exit pupil area, and are coupled out for imaging in the exit pupil area. In the embodiment of the invention, the optical waveguide assembly can realize excellent optical performance under a thinner condition, so that the transparency of the display is improved, a thinner transparent display can be manufactured, the structure is simpler, the convenience is improved, and the manufacturing cost is reduced; and increases the field of view of the transparent display and improves the resolution, thereby improving the uniformity of the transparent display.

Description

Transparent display based on AR optical waveguide technology

Technical Field

The invention relates to the technical field of AR transparent display, in particular to a transparent display based on AR optical waveguide technology.

Background

Transparent displays, typically referred to as transparent screens when not in use, produce a transparent effect; when the display screen is used, the display screen has no transparent effect (but the transparent effect can be generated in a blank area of the display screen, namely an area where a picture is not displayed, and the area is in a standby state at the moment, and the transparent effect is consistent with that when the display screen is not used). Existing transparent displays generally include the following types based on transparent display principles: OLED transparent screen, LED transparent screen, LCD transparent screen. The transparent displays of the above types can realize basic transparent display effects and have the characteristics. However, the conventional transparent display also has a plurality of problems, such as complex transparent display structure and often requires multiple layers of matching, which results in low transparency of the conventional transparent display; and the traditional transparent display has poor effect in the aspect of display, and does not have a uniform display picture, which also has damage to the vision of the user. Therefore, the transparency and display uniformity of the conventional transparent display are required to be improved.

Disclosure of Invention

The invention aims to provide a transparent display based on an AR optical waveguide technology, and aims to solve the problems of low transparency and poor display uniformity of the traditional transparent display.

The embodiment of the invention provides a transparent display based on AR optical waveguide technology, which comprises an optical waveguide assembly, an optical engine and a frame; the optical waveguide assembly and the optical engine are both arranged in the frame; the optical waveguide assembly includes a grating unit including: the optical engine comprises an entrance pupil grating unit, a pupil expansion grating unit and an exit pupil grating unit which are respectively used for forming an entrance pupil area, a pupil expansion area and an exit pupil area, wherein light rays coupled out of the optical engine are sequentially transmitted in the entrance pupil area, the pupil expansion area and the exit pupil area, and are coupled out for imaging in the exit pupil area.

Further, the optical waveguide assembly comprises a waveguide substrate, and the grating unit is arranged on one surface or two surfaces of the waveguide substrate.

Further, the grating unit is manufactured on the waveguide substrate by adopting a surface relief process or volume holographic exposure.

Further, the optical waveguide assembly further comprises a protective layer, wherein the protective layer is attached to one surface or two surfaces of the waveguide substrate and is arranged at intervals with the waveguide substrate.

Further, a gap between the protective layer and the waveguide substrate is less than or equal to 0.2mm.

Further, the protective layer and the waveguide substrate are fixed through supporting glue on the periphery.

Further, the optical waveguide assembly further includes: and the transmittance adjusting layer is arranged on the opposite surface of the imaging side of the waveguide substrate.

Further, the transmittance adjusting layer is a liquid crystal layer, an electrochromic sheet or a photochromic sheet.

Further, the device also comprises a shielding layer for shielding the entrance pupil area and/or the expansion pupil area.

Furthermore, the pupil expansion grating unit and the exit pupil grating unit are grating units which are independently arranged and are used for respectively carrying out pupil expansion and coupling-out imaging; or the pupil expansion grating unit and the exit pupil grating unit are two-dimensional grating units which are integrally arranged and are used for simultaneously carrying out pupil expansion and coupling-out imaging.

Compared with the prior art, the invention has the beneficial effects that: and the optical waveguide assembly is used as a light propagation carrier, light coupled out by the optical engine sequentially propagates in the entrance pupil area, the expansion pupil area and the exit pupil area, and is coupled out for imaging in the exit pupil area. In the embodiment of the invention, the optical waveguide assembly can realize excellent optical performance under a thinner condition, so that the transparency of the display is improved, a thinner transparent display can be manufactured, the structure is simpler, the convenience is improved, and the manufacturing cost is reduced; and increases the field of view of the transparent display and improves the resolution, thereby improving the uniformity of the transparent display.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of a transparent display based on AR optical waveguide technology according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a transparent display based on AR optical waveguide technology according to a second embodiment of the present invention;

fig. 3 is a schematic structural diagram III of a transparent display based on AR optical waveguide technology according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of a transparent display based on AR optical waveguide technology according to an embodiment of the present invention;

FIG. 5 is a schematic diagram showing light propagation of a transparent display based on AR optical waveguide technology according to an embodiment of the present invention;

FIG. 6 is a schematic diagram showing light propagation of a transparent display based on AR optical waveguide technology according to an embodiment of the present invention;

FIG. 7 is a cross-sectional view I of a transparent display based on AR optical waveguide technology provided by an embodiment of the present invention;

FIG. 8 is a second cross-sectional view of a transparent display based on AR optical waveguide technology according to an embodiment of the present invention;

FIG. 9 is a schematic diagram illustrating the operation of a grating unit of a transparent display according to an embodiment of the present invention;

fig. 10 is a schematic diagram showing a second operation of a grating unit of a transparent display based on AR optical waveguide technology according to an embodiment of the present invention.

The figure identifies the description:

10. an optical waveguide assembly; 11. a grating unit; 12. a waveguide substrate; 13. a protective layer; 14. supporting glue; 15. a transmittance adjustment layer;

20. a light engine; 21. a corner prism;

30. a frame;

100. an entrance pupil region; 200. a pupil expansion region; 300. an exit pupil region; 400. a first ray of light; 500. a second ray; 600. light ray III; 700. light ray IV; 800. fifth ray; 900. a two-dimensional grating region.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It should be understood that the terms "comprises" and "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It is also to be understood that the terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this specification and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It should be further understood that the term "and/or" as used in the present specification and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes such combinations.

Referring to fig. 1 to 6, a transparent display based on AR optical waveguide technology according to an embodiment of the present invention includes an optical waveguide assembly 10, an optical engine 20, and a frame 30; the optical waveguide assembly 10 and the light engine 20 are both disposed within the frame 30; the optical waveguide assembly 10 includes a grating unit 11, and the grating unit 11 includes: the entrance pupil grating unit, the expansion pupil grating unit, and the exit pupil grating unit, which are respectively used to form the entrance pupil area 100, the expansion pupil area 200, and the exit pupil area 300, light coupled out of the light engine 20 sequentially propagates in the entrance pupil area 100, the expansion pupil area 200, and the exit pupil area 300, and is coupled out for imaging in the exit pupil area 300.

In this embodiment, the optical waveguide assembly 10 is fixed on the frame 30, the light engine 20 is located in the frame 30, and the light engine 20 is further provided with a corner prism 21 (shown in fig. 3), where the corner prism 21 can refract the light emitted by the light engine 20; the light engine 20 is fixed on the frame 30 by means of glue, screws, etc., and at this time, the position and angle relationship between the light engine 20 and the optical waveguide assembly 10 will not change with normal or abnormal use of the user; the display area of the optical waveguide assembly 10 is unobstructed.

It should be noted that the grating unit 11 is a very small optical device in practical applications, and the grating unit 11 is enlarged (as shown in fig. 5) for the convenience of understanding. In addition, the AR optical waveguide technology (ARWaveguide Technology) is an optical technology applied in Augmented Reality (AR) devices. The AR light guide technology can project virtual content into a real scene in a user's field of view, so that a user can see the scene in which a virtual image is combined with a real object, and a richer user experience is provided. In AR optical waveguide technology, the core is the waveguide (i.e., optical waveguide assembly 10, hereinafter referred to as "optical waveguide assembly") which is a very thin optical element, the structure of which is typically composed of several different laminated materials, including transparent substrates, grating layers (grating units), etc., the combination of which allows the waveguide to have excellent optical properties in the case of being very thin. The embodiment of the invention can manufacture a lighter and thinner transparent display by applying the AR optical waveguide technology, simplifies the complexity of a transparent structure, thereby improving the comfort, portability and transparency of the display, and controlling the cost to be lower in the production process; the optical waveguide assembly can guide light from the entrance to the exit, the function of displaying the virtual image on the device is realized, the virtual image can be reflected and diffused in the waveguide through the optical waveguide assembly, and finally, the eyes of a user are achieved.

The entrance pupil area 100, the mydriatic area 200, and the exit pupil area 300 are described below with reference to fig. 5: the entrance pupil area 100 is disposed at a corner of the frame 30 and functions to propagate light emitted from the light engine 20 for imaging into the interior of the optical waveguide assembly 10; when light passes through the grating unit 11, light diffraction phenomenon occurs, and most of light propagation angles change, so that the light diffraction propagation angles can meet the condition of total reflection in the optical waveguide assembly 10 by designing different grating periods, and the light can propagate in the optical waveguide assembly 10. The mydriasis area 200 is arranged between the entrance pupil area 100 and the exit pupil area 300, and plays a role in turning the light transmitted from the direction of the entrance pupil area 100, so that the turned light continuously propagates into the exit pupil area 300 in a total reflection manner along the turning direction; meanwhile, the grating (namely the pupil expansion grating unit) in the pupil expansion area 200 is designed to play a role similar to a half-mirror, so that a part of light rays can turn and enter the exit pupil area 300 while ensuring that a part of light rays continue to propagate; at this time, the mydriasis area 200 may replicate the image of the entrance pupil, so that the lateral eyepiece area when the exit pupil area 300 is imaged may enable the observer to have a larger observation range (i.e., eyebox, a cone area between the near-eye display optical module and the eyeball, and also the area with the clearest display content, hereinafter the same applies); the exit pupil area 300 serves as an imaging observation area of a user, has the largest occupation ratio in the optical waveguide assembly 10, and plays a role in coupling light transmitted from the pupil expansion area 200 out of the waveguide for imaging, and meanwhile, the exit pupil area 300 also has the role in copying an entrance pupil along the light transmission direction, so that a vertical eyepiece area can be enlarged; for ease of understanding, the exit pupil area 300 may be considered approximately as an eyepiece area.

The following describes in detail the flow of light propagating in the optical waveguide assembly 10 in a transparent display based on AR optical waveguide technology, as shown in fig. 6: the light engine 20 (the light engine can be a light engine capable of performing full-color output, the driving mode can be any one of microled, DLP, LBS or LCOS, the resolution is at least 480p, the output luminous flux is at least 2.5 lumens under the stable condition; the invention adopts the light engine type of DLP as an example, and of course, the light engine type can also be other alternative light engine types) in which the light emitting elements LED respectively emit light rays of red, green and blue three colors, and the light rays are coupled out into the entrance pupil area 100 of the optical waveguide assembly 10 through the effective reflection area of a DMD (micro electro mechanical system (a micro-mechanical system) of electronic input and optical output) of the DLP after being collimated and split by a series of lenses in the light engine 20 and combined, and the light rays at the moment are 400 marked in FIG. 6; the first light ray 400 passes through the diffraction of the entrance pupil grating unit in the entrance pupil area 100, and most of the light ray enters the inside of the optical waveguide assembly 10 to propagate in the optical waveguide assembly 10 in a total reflection mode; while a small part of the light rays continue to propagate forwards through the optical waveguide assembly 10, at this time, the small part of the light rays need to be covered by a structural member made of black materials to improve the use experience; the light loss can be recycled by shielding with silver film material or material like a total reflection mirror.

Further, the light beam entering the waveguide for total reflection enters the mydriatic region 200 after being transmitted by total reflection of a certain distance, and the turning angle designed in the mydriatic grating unit of the mydriatic region 200 just enables the turning angle of the light beam two 500 transmitted by the entrance mydriatic region 100 to be transmitted in the direction of the exit mydriatic region 300, and at the moment, the design similar to the half-mirror in the mydriatic region 200 can ensure that the image replicates itself while being transmitted forwards, so that the visible region of the image is enlarged along with the light transmission direction. Light ray two 500 transmitted in the pupil expansion area 200 enters the exit pupil area 300 through total reflection of one section of waveguide after exiting from the pupil expansion area 200, light ray three 600 transmitted in the exit pupil area 300 can be changed into a coupled waveguide-out state from a total reflection state through diffraction of the exit pupil grating unit, at the moment, light ray four 700 enters human eyes for imaging, and is coupled out on two sides of the optical waveguide assembly 10, so that the coupling efficiency of the front side (namely one side of a user) is higher than that of the back side by more than 50%, and meanwhile, light ray five 800 outside the optical waveguide assembly 10 can be imaged together with light ray four 700 through the optical waveguide assembly 10, so that the effect of superposition display in augmented reality is achieved.

In one embodiment, the optical waveguide assembly 10 includes a waveguide substrate 12, and the grating unit 11 is disposed on one or both sides of the waveguide substrate 12.

In this embodiment, the waveguide substrate 12 is a uniform medium with a relatively high refractive index, typically glass, or a transparent material with high surface flatness such as resin and high refractive index, and can be used as a space for total reflection of light. The grating units 11 may be disposed on one side of the waveguide substrate 12 (the side where the user is preferentially disposed), or may be disposed on both sides of the waveguide substrate 12, and the greater the number of grating units 11 disposed, the higher the brightness of the final image, and the greater the number of grating units 11 disposed may be according to the actual use situation.

In one embodiment, the grating unit 11 is fabricated on the waveguide substrate 12 using a surface relief process or a volume holographic exposure.

In the present embodiment, one or both sides of the waveguide substrate 12 are embossed with the grating unit 11 by a surface relief process; one or both sides of the waveguide substrate 12 may also be provided with a grating unit 11 by volume holographic exposure, which may be alternatively chosen as desired.

As shown in fig. 7 and 8, in an embodiment, the optical waveguide assembly 10 further includes a protective layer 13, where the protective layer 13 is attached to one or both sides of the waveguide substrate 12 and is spaced from the waveguide substrate 12.

In this embodiment, in order to protect the grating unit 11 and not to destroy the total reflection condition of light propagating in the optical waveguide assembly 10, a corresponding protection layer 13 needs to be provided; the area size of the protective layer 13 corresponds to the area size of the waveguide substrate 12, and the protective layer 13 can be understood as a protective film; of course, the protective layers 13 are disposed on both sides of the waveguide substrate 12, so that the waveguide substrate 12 can be protected to the greatest extent. In addition, the protective layer 13 needs to be provided at a distance from the waveguide substrate 12 so as not to crush the grating unit 11 on the waveguide substrate 12.

In one embodiment, the gap between the protective layer 13 and the waveguide substrate 12 is less than or equal to 0.2mm.

In the present embodiment, if the gap between the waveguide substrate 12 and the protective layer 13 is too large, the protective layer 13 may not function as a protection, and considering the problem of the thickness of the waveguide substrate 12, the gap between the waveguide substrate 12 and the protective layer 13 is generally reduced as much as possible without damaging the total reflection condition, and therefore, it is necessary to set the gap to be less than or equal to 0.2mm, and the gap may be within this range.

In one embodiment, the protection layer 13 and the waveguide substrate 12 are fixed by a supporting glue 14 on the peripheral side.

In this embodiment, a circle is fixed between the protective layer 13 and the waveguide substrate 12 along the edge of the waveguide substrate 12 by the supporting glue 14, and then a layer of protective layer 13 is covered; it should be noted that, the width of the supporting glue 14 is preferably less than or equal to 1mm, and if the width of the supporting glue 14 is too large, the external shape size, imaging effect, aesthetic degree, etc. of the waveguide substrate 12 may be affected; in general, the supporting glue 14 is set to a stable width value according to the process production for mass production. It should be noted that the supporting glue 14 may be a common glue used in the art, and may be capable of achieving a bonding function, for example, a transparent glue which is not easy to age and change color, or a black glue may be optionally disposed on a side surface of the waveguide substrate 12 to avoid light reflection.

In one embodiment, the optical waveguide assembly 10 further comprises: the transmittance adjustment layer 15. The transmittance adjustment layer 15 is disposed on the waveguide substrate 12 opposite to the imaging side.

In this embodiment, a transmittance adjustment layer 15 is attached to the back surface (i.e., the opposite surface of the user's viewing side, the same applies hereinafter), and the transmittance of the entire optical waveguide assembly 10 can be changed without changing the transmittance of the front surface (i.e., the opposite surface of the user's viewing side, the same applies hereinafter) of the waveguide substrate 12 by energizing and controlling the voltage, so that the transmittance can be reduced to at least 30% at the minimum, but the transmittance of the front surface of the waveguide substrate 12 is not affected. Note that, if the transmittance adjustment layer 15 is added to the waveguide substrate 12, the protective layer 13 is only required to be disposed on the transmittance adjustment layer 15, and the transmittance adjustment layer 15 is directly connected to the waveguide substrate 12 through the supporting glue 14.

Specifically, taking fig. 7 as an example, a grating unit 11 is disposed on the front surface of a waveguide substrate 12, and then a protective layer 13 and the grating unit 11 are disposed at intervals through a supporting adhesive 14; the back of the waveguide substrate 12 is spaced from the transmittance adjusting layer 15 by the supporting adhesive 14, and the other protective layer 13 is attached to the transmittance adjusting layer 15, so that the protective layer 13 protects both sides of the waveguide substrate 12. Additional grating elements 11 can be added on their own to the back side of the waveguide substrate 12, which can be adjusted according to the actual situation.

In one embodiment, the transmittance adjustment layer 15 is a liquid crystal layer, an electrochromic or a photochromic sheet.

In this embodiment, the transmittance adjustment layer 15 may be a liquid crystal layer, a photochromic sheet or a photochromic glass, or an electrochromic sheet or an electrochromic glass, as long as the transmittance of the entire optical waveguide assembly 10 can be dynamically changed.

In an embodiment, an occlusion layer for occluding the entrance pupil area 100 and/or the mydriatic area 200 is also included.

In this embodiment, the entrance pupil area 100 and the pupil expansion area 200 near the light engine 20 may leak light to affect the use, and the light leaking positions may be blocked by black materials (i.e. the blocking layer) to ensure that the light does not leak to affect the use.

As shown in fig. 9 and 10, in an embodiment, the mydriatic grating unit and the exit pupil grating unit are separately provided grating units 11, for performing mydriatic and coupled imaging, respectively; or the pupil expansion grating unit and the exit pupil grating unit are two-dimensional grating units which are integrally arranged and are used for simultaneously carrying out pupil expansion and coupling-out imaging.

In this embodiment, the pupil expansion grating unit and the exit pupil grating unit may be grating units 11 which are independently arranged, and at this time, the optical waveguide assembly 10 is difficult to occupy a larger area, but the placement position and the ID design of the optical engine 20 are more flexible; the pupil expansion grating unit and the exit pupil grating unit may be two-dimensional grating units which are integrally arranged, light projected by the optical engine 20 enters the pupil entrance area 100 and then is coupled into the waveguide substrate 12 to propagate, and when entering the two-dimensional grating area 900, the light is coupled out of the waveguide to form an image while being expanded, at this time, the optical waveguide assembly 10 is easy to achieve a large screen duty ratio, but the placement position and the ID design of the optical engine 20 are limited.

In summary, the AR optical waveguide technology is applied to the transparent display, and the AR optical waveguide technology can simply and efficiently realize the transparent display effect, so that the transparency of the display is greatly improved, and the transparent display structure can realize the transparent display without complex arrangement, namely, the complexity of the transparent display structure is reduced; meanwhile, the characteristics of infinite imaging by utilizing the AR optical waveguide technology can play a role in protecting eyes.

In the description, each embodiment is described in a progressive manner, and each embodiment is mainly described by the differences from other embodiments, so that the same similar parts among the embodiments are mutually referred. It should be noted that it will be apparent to those skilled in the art that various modifications and adaptations of the invention can be made without departing from the principles of the invention and these modifications and adaptations are intended to be within the scope of the invention as defined in the following claims.

It should also be noted that in this specification, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or the like that comprises the element.

Claims (10)

1. A transparent display based on AR optical waveguide technology is characterized by comprising an optical waveguide assembly, an optical engine and a frame; the optical waveguide assembly and the optical engine are both arranged in the frame;

the optical waveguide assembly includes a grating unit including: the optical engine comprises an entrance pupil grating unit, a pupil expansion grating unit and an exit pupil grating unit which are respectively used for forming an entrance pupil area, a pupil expansion area and an exit pupil area, wherein light rays coupled out of the optical engine are sequentially transmitted in the entrance pupil area, the pupil expansion area and the exit pupil area, and are coupled out for imaging in the exit pupil area.

2. The AR optical waveguide technology based transparent display of claim 1, wherein the optical waveguide assembly comprises a waveguide substrate, and the grating unit is disposed on one or both sides of the waveguide substrate.

3. The AR optical waveguide technology based transparent display according to claim 2, wherein the grating unit is fabricated on the waveguide substrate using a surface relief process or a volume holographic exposure.

4. The AR optical waveguide technology based transparent display of claim 2, wherein the optical waveguide assembly further comprises a protective layer attached to one or both sides of the waveguide substrate and spaced apart from the waveguide substrate.

5. The AR optical waveguide technology based transparent display of claim 4, wherein a gap between the protective layer and the waveguide substrate is less than or equal to 0.2mm.

6. The AR optical waveguide technology based transparent display according to claim 4, wherein the protective layer and the waveguide substrate are fixed by a supporting paste on the peripheral side.

7. The AR optical waveguide technology based transparent display of claim 2, wherein the optical waveguide assembly further comprises: and the transmittance adjusting layer is arranged on the opposite surface of the imaging side of the waveguide substrate.

8. The AR optical waveguide technology based transparent display of claim 7, wherein the transmittance adjustment layer is a liquid crystal layer, an electrochromic or a photochromic sheet.

9. The AR light guide technology based transparent display according to claim 1, further comprising an occlusion layer for occluding the entrance pupil area and/or the mydriatic area.

10. The AR optical waveguide technology based transparent display according to claim 1, wherein the pupil expansion grating unit and the exit pupil grating unit are separately arranged grating units for performing pupil expansion and coupled imaging, respectively; or the pupil expansion grating unit and the exit pupil grating unit are two-dimensional grating units which are integrally arranged and are used for simultaneously carrying out pupil expansion and coupling-out imaging.

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