A transparent display based on AR optical waveguide technology

Abstract

The application discloses a transparent display based on AR optical waveguide technology, comprising an optical waveguide assembly, an optical engine and a frame; the optical waveguide assembly and the optical engine are arranged in the frame; the optical waveguide assembly comprises a grating unit, the grating unit comprises an entrance pupil grating unit, an expansion pupil grating unit and an exit pupil grating unit for forming an entrance pupil area, an expansion pupil area and an exit pupil area respectively, light coupled out by the optical engine propagates in the entrance pupil area, the expansion pupil area and the exit pupil area in sequence for entrance pupil, expansion pupil and exit pupil, and is coupled out to form an image in the exit pupil area. In the embodiment of the application, the optical waveguide assembly can realize excellent optical performance under the condition of being thin, thereby improving the transparency of the display, enabling the transparent display to be lighter and thinner, the structure being simpler, the convenience being improved and the manufacturing cost being reduced; and the field of view of the transparent display is increased and the resolution is improved, thereby improving the uniformity of the transparent display.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of AR transparent display, in particular to a transparent display based on AR optical waveguide technology. BACKGROUND

[0002] The transparent display generally refers to a transparent screen when not in use, and a display screen without transparent effect when in use (but a transparent effect can also be produced in the blank area of the display screen, i.e. the area without displaying pictures, at this time the area is in standby state, and the transparent effect is consistent with that when not in use). The existing transparent display based on transparent display principle generally includes the following types: OLED transparent screen, LED transparent screen and LCD transparent screen. The transparent display of each type can achieve basic transparent display effect and has respective characteristics. However, the existing transparent display also has many problems, for example, the transparent display structure is relatively complex, and often needs to be matched by multiple layers, which leads to low transparency of the traditional transparent display; and the traditional transparent display has poor display effect and cannot achieve relatively uniform display picture, which also damages the vision of the user. Therefore, the transparency and display uniformity of the traditional transparent display need to be improved. SUMMARY

[0003] The purpose of the present application is to provide a transparent display based on AR optical waveguide technology, aiming to solve the problems of low transparency and poor display uniformity of the traditional transparent display.

[0004] The present application provides a transparent display based on AR optical waveguide technology, which comprises a light waveguide assembly, a light engine and a frame; the light waveguide assembly and the light engine are arranged in the frame; the light waveguide assembly comprises a grating unit, which comprises an entrance pupil grating unit, an expansion pupil grating unit and an exit pupil grating unit for forming an entrance pupil area, an expansion pupil area and an exit pupil area respectively; the light rays coupled out by the light engine propagate in the entrance pupil area, the expansion pupil area and the exit pupil area in sequence for entrance, expansion and exit, and are coupled out for imaging in the exit pupil area.

[0005] Further, the light waveguide assembly comprises a waveguide substrate, and the grating unit is arranged on one side or both sides of the waveguide substrate.

[0006] Further, the grating unit is made on the waveguide substrate by surface relief process or volume holographic exposure.

[0007] Further, the light waveguide assembly further comprises a protective layer, which is attached to one side or both sides of the waveguide substrate and is arranged in a spaced manner with the waveguide substrate.

[0008] Further, the gap between the protective layer and the waveguide substrate is less than or equal to 0.2mm.

[0009] Further, the gap between the protective layer and the waveguide substrate is fixed by the support glue on the periphery.

[0010] Further, the light waveguide assembly further comprises a transmittance adjustment layer arranged on the opposite side of the waveguide substrate on the imaging side.

[0011] Further, the transmittance adjustment layer is a liquid crystal layer, an electrochromic sheet or a photochromic sheet.

[0012] Further, it further comprises a shielding layer for shielding the entrance pupil area and / or the pupil expansion area.

[0013] Further, the pupil expansion grating unit and the exit pupil grating unit are independently arranged grating units for respectively performing pupil expansion and out-coupling imaging; or the pupil expansion grating unit and the exit pupil grating unit are integrated two-dimensional grating units for simultaneously performing pupil expansion and out-coupling imaging.

[0014] The beneficial effects of the present application compared with the prior art are: the light waveguide assembly is used as a light propagation carrier, and the light coupled out by the light engine propagates in the entrance pupil area, the pupil expansion area and the exit pupil area in sequence for entrance, pupil expansion and exit, and out-coupling imaging in the exit pupil area. In the embodiment of the present application, the light waveguide assembly can realize excellent optical performance under the condition of being thin, thereby improving the transparency of the display, enabling the production of a thinner transparent display, having a simpler structure, improving convenience and reducing production cost; and increasing the field of view of the transparent display and improving the resolution, thereby improving the uniformity of the transparent display. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0016] Figure 1 Structure diagram of the transparent display based on AR light waveguide technology provided by the embodiment of the present application Figure 1

[0017] Figure 2 Structure diagram of the transparent display based on AR light waveguide technology provided by the embodiment of the present application Figure 2

[0018] Figure 3 ​​Structure diagram of transparent display based on AR light waveguide technology provided by the embodiment of the present application Figure 3 ;

[0019] Figure 4 Structure diagram of transparent display based on AR light waveguide technology provided by the embodiment of the present application Figure 4 ;

[0020] Figure 5 Light propagation diagram of transparent display based on AR light waveguide technology provided by the embodiment of the present application Figure 1 ;

[0021] Figure 6 Light propagation diagram of transparent display based on AR light waveguide technology provided by the embodiment of the present application Figure 2 ;

[0022] Figure 7 Sectional view of transparent display based on AR light waveguide technology provided by the embodiment of the present application Figure 1 ;

[0023] Figure 8 Sectional view of transparent display based on AR light waveguide technology provided by the embodiment of the present application Figure 2 ;

[0024] Figure 9 Working diagram of grating unit of transparent display based on AR light waveguide technology provided by the embodiment of the present application Figure 1 ;

[0025] Figure 10 Working diagram of grating unit of transparent display based on AR light waveguide technology provided by the embodiment of the present application Figure 2 .

[0026] Explanation of marks in the figure:

[0027] 10, light waveguide assembly; 11, grating unit; 12, waveguide substrate; 13, protective layer; 14, supporting glue; 15, transmittance adjustment layer;

[0028] 20, light engine; 21, corner prism;

[0029] 30, frame;

[0030] 100, entrance pupil area; 200, pupil expanding area; 300, exit pupil area; 400, light ray one; 500, light ray two; 600, light ray three; 700, light ray four; 800, light ray five; 900, two-dimensional grating area. DETAILED DESCRIPTION

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0033] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit 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 unless the context clearly indicates otherwise.

[0034] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0035] Combination Figures 1 to 6 As shown, an embodiment of the present invention provides a transparent display based on AR optical waveguide technology, including an optical waveguide component 10, an optical engine 20, and a frame 30; the optical waveguide component 10 and the optical engine 20 are both disposed within the frame 30; the optical waveguide component 10 includes a grating unit 11, the grating unit 11 including: an entrance pupil grating unit, an expansion pupil grating unit, and an exit pupil grating unit respectively for forming an entrance pupil region 100, an expansion pupil region 200, and an exit pupil region 300; the light coupled out by the optical engine 20 propagates sequentially in the entrance pupil region 100, the expansion pupil region 200, and the exit pupil region 300, and is coupled out in the exit pupil region 300 to form an image.

[0036] In this embodiment, the optical waveguide assembly 10 is fixed on the frame 30, the optical engine 20 is located inside the frame 30, and the optical engine 20 is also provided with a corner prism 21. Figure 3 As shown in the diagram, the corner prism 21 can refract the light emitted by the light engine 20; while the light engine 20 is fixed to the frame 30 by adhesive, screws and other components. At this time, the position and angle relationship between the light engine 20 and the light waveguide assembly 10 will not change with the user's normal or abnormal use; the display area of ​​the light waveguide assembly 10 is unobstructed.

[0037] It should be noted that the grating unit 11 is a very small optical device in actual application, and the present application enlarges the grating unit 11 for the convenience of understanding (as shown in Figure 5 In addition, the AR waveguide technology is an optical technology applied in an augmented reality (AR) device. The AR waveguide technology can project virtual content into a real scene in the user's field of view, so that the user can see a scene in which virtual images are combined with real objects, providing a more rich user experience. In the AR waveguide technology, the core is a waveguide (i.e., the optical waveguide assembly 10, the same below). The optical waveguide assembly is a very thin optical element, and its structure is usually composed of several different layers of stacked materials, including a transparent substrate, a grating layer (grating unit), etc. The combination of these layers of stacked materials can make the waveguide have excellent optical performance in a very thin case. The application of the AR waveguide technology in the embodiment of the present application can make the transparent display thinner and lighter, simplify the complexity of the transparent structure, thereby improving the comfort, portability and transparency of the display, and the cost can be controlled lower in the production process; the optical waveguide assembly can guide light from the entrance to the exit, realize the function of displaying virtual images on the device, and make the virtual images reflect and diffuse inside the waveguide through the optical waveguide assembly, finally reach the user's eyes. This display mode can realize a larger field of view and higher resolution, thereby improving the uniformity of the display.

[0038] The following will be described in combination with Figure 5As shown, the entry pupil area 100, the pupil expansion area 200 and the exit pupil area 300 are described respectively: the entry pupil area 100 is arranged at the corner of the frame 30, which plays a role of coupling the light emitted by the light engine 20 for imaging into the internal propagation of the optical waveguide assembly 10; when the light passes through the grating unit 11, the diffraction of light occurs, and the propagation angle of most light changes, and by designing different grating periods, the propagation angle of the diffracted light can meet the condition of total reflection in the optical waveguide assembly 10, so that the light can propagate inside the optical waveguide assembly 10. The pupil expansion area 200 is arranged between the entry pupil area 100 and the exit pupil area 300, which plays a role of turning the light propagating from the entry pupil area 100, so that the turned light continues to propagate by total reflection into the exit pupil area 300 along the turning direction; at the same time, the grating (i.e. the pupil expansion grating unit) in the pupil expansion area 200 can play a role similar to a half-transmission half-reflection mirror, which can turn part of the light into the exit pupil area 300 while ensuring the continuous propagation of part of the light; at this time, the pupil expansion area 200 can copy the image of the entry pupil, so that the lateral eyebox area in the exit pupil area 300 can make the observer have a larger observation range (i.e. a conical area between the near-eye display optical module and the eyeball, which is also the area with the clearest display content, the same below); the exit pupil area 300 is the imaging observation area of the user, which has the largest proportion in the optical waveguide assembly 10, and plays a role of coupling the light propagating from the pupil expansion area 200 out of the waveguide for imaging, and at the same time, the exit pupil area 300 also has a role of copying the entry pupil along the light propagation direction, which can expand the vertical eyebox area; for the convenience of understanding, the exit pupil area 300 can be approximately regarded as the eyebox area.

[0039] As shown in FIG. 1, Figure 6 As shown in FIG. 1, the light emitting elements LED in the light engine 20 emit red, green and blue light respectively, and after collimating and splitting light by a series of lenses inside the light engine 20 and then combining light, the light is coupled out of the light engine 20 into the entry pupil area 100 of the optical waveguide assembly 10 through the effective reflection area of the DMD (a kind of micro-electromechanical system with electronic input and optical output) of the DLP, at this time, the light is the light of the first order diffraction, which can propagate in the optical waveguide assembly 10 by total reflection. Figure 6The light ray one 400 is marked. The light ray one 400 diffracts through the entrance pupil grating unit in the entrance pupil area 100. Most of the light rays enter the light waveguide assembly 10 and propagate in the light waveguide assembly 10 in the form of total reflection. A small part of the light rays continues to propagate forward through the light waveguide assembly 10. At this time, the small part of the light rays needs to be covered by a structural member made of black material to improve the use experience. The silver film material or the similar total reflection mirror material can also be used for shielding. In this way, the lost light can be reused.

[0040] Further, the light rays entering the waveguide total reflection propagate through a distance and enter the pupil expansion area 200. The turning angle designed in the pupil expansion grating unit in the pupil expansion area 200 is just right to make the turning angle of the light ray two 500 propagating from the entrance pupil area 100 align with the direction of the exit pupil area 300. At this time, the design of the pupil expansion area 200 similar to the half-transmission half-reflection mirror can ensure that the image is copied while propagating forward. In this way, the visible area of the image becomes larger along the direction of the light ray. The light ray two 500 propagating from the pupil expansion area 200 enters the exit pupil area 300 through waveguide total reflection. The light ray three 600 propagating in the exit pupil area 300 diffracts through the exit pupil grating unit, and changes from the total reflection state to the state of coupling out of the waveguide. At this time, the light ray four 700 enters the human eye to form an image. The light waveguide assembly 10 is coupled out from both sides. Through the design, the coupling-out efficiency of the front side (i.e., the side of the user) is more than 50% higher than the coupling-out efficiency of the back side. At the same time, the light ray five 800 outside the light waveguide assembly 10 can transmit through the light waveguide assembly 10 and form an image with the light ray four 700 in front of the user's eyes, achieving the effect of superimposed display in augmented reality.

[0041] In an embodiment, the light waveguide assembly 10 includes a waveguide substrate 12, and the grating unit 11 is arranged on one side or both sides of the waveguide substrate 12.

[0042] In the embodiment, the waveguide substrate 12 is a kind of uniform medium with relatively high refractive index, which is generally glass, and can also be resin or other transparent materials with high surface flatness and high refractive index, and can be used as a space for total reflection of light rays. The grating unit 11 can be arranged on one side (preferably the side of the user) of the waveguide substrate 12, or on both sides of the waveguide substrate 12. The more the grating units 11 are arranged, the higher the brightness of the final image. The number of grating units 11 arranged can be set according to actual use.

[0043] In an embodiment, the grating unit 11 is made on the waveguide substrate 12 by using a surface relief process or volume holographic exposure.

[0044] In the embodiment, one or both sides of the waveguide substrate 12 are imprinted with the grating units 11 by a surface relief process; one or both sides of the waveguide substrate 12 can also be exposed to a volume hologram to make the grating units 11, which is an alternative solution and can be selected as required.

[0045] In combination Figure 7 and Figure 8 As shown in FIGS. 1, 2, 3, and 4, in an embodiment, the optical waveguide assembly 10 further comprises a protective layer 13, which is attached to one or both sides of the waveguide substrate 12 and is spaced apart from the waveguide substrate 12.

[0046] In the embodiment, the protective layer 13 is needed to protect the grating units 11 and not to destroy the total reflection condition of the light propagating in the optical waveguide assembly 10; the size of the protective layer 13 corresponds to the size of the waveguide substrate 12, and the protective layer 13 can be understood as a protective film; of course, the waveguide substrate 12 can be protected to the greatest extent by arranging the protective layer 13 on both sides of the waveguide substrate 12. In addition, the protective layer 13 needs to be spaced apart from the waveguide substrate 12 to avoid crushing the grating units 11 on the waveguide substrate 12.

[0047] In an embodiment, the gap between the protective layer 13 and the waveguide substrate 12 is less than or equal to 0.2 mm.

[0048] In the embodiment, if the gap between the waveguide substrate 12 and the protective layer 13 is too large, the protective layer 13 may not be able to play a protective role, and considering the thickness of the waveguide substrate 12, the gap between the waveguide substrate 12 and the protective layer 13 is generally as small as possible without destroying the total reflection condition, therefore, the gap needs to be set to be less than or equal to 0.2 mm, and the gap can be within this range.

[0049] In an embodiment, the protective layer 13 and the waveguide substrate 12 are fixed by the support glue 14 on the periphery.

[0050] In the embodiment, the support glue 14 is fixed along the edge of the waveguide substrate 12 between the protective layer 13 and the waveguide substrate 12, and then a layer of protective layer 13 is covered; it should be noted that the width of the support glue 14 is preferably less than or equal to 1 mm, and if the width of the support glue 14 is too large, it may affect the size, imaging effect, and aesthetic level of the waveguide substrate 12; in general, the support glue 14 can be produced in a stable width value according to the process to produce in batches. It should be noted that the support glue 14 can be a commonly used glue in the art, which can achieve the bonding function, such as transparent and not easy to age discoloration glue, and black glue can also be selected to be arranged on the side of the waveguide substrate 12 to avoid light reflection.

[0051] In one embodiment, the optical waveguide assembly 10 further includes a transmittance adjustment layer 15, which is disposed on the opposite side of the imaging side of the waveguide substrate 12.

[0052] In this embodiment, a transmittance adjustment layer 15 is attached to the back side of the waveguide substrate 12 (i.e., the opposite side to the user's viewing side, hereinafter the same). By applying power and controlling the voltage, the overall transmittance of the optical waveguide assembly 10 can be changed without altering the transmittance of the front side of the waveguide substrate 12 (i.e., the user's viewing side, hereinafter the same). The transmittance can be reduced to at least 30% without affecting the transmittance of the front side of the waveguide substrate 12. It should be noted that if a transmittance adjustment layer 15 is added to the waveguide substrate 12, only a protective layer 13 needs to be provided on the transmittance adjustment layer 15, and the transmittance adjustment layer 15 can be directly connected to the waveguide substrate 12 through the support adhesive 14.

[0053] Specifically, with Figure 7 For example, a grating unit 11 is disposed on the front side of the waveguide substrate 12, and a protective layer 13 is disposed between the grating unit 11 and the protective layer 13 via a support adhesive 14. On the back side of the waveguide substrate 12, a transmittance adjustment layer 15 is disposed between the protective adhesive 14 and the transmittance adjustment layer 15, and another protective layer 13 is then attached to the transmittance adjustment layer 15. Thus, the protective layer 13 provides protection for both sides of the waveguide substrate 12. Additional grating units 11 can also be added to the back side of the waveguide substrate 12, and adjustments can be made according to the specific circumstances.

[0054] In one embodiment, the transmittance adjustment layer 15 is a liquid crystal layer, an electrochromic film, or a photochromic film.

[0055] In this embodiment, the transmittance adjustment layer 15 can be a liquid crystal layer, a photochromic sheet or photochromic glass, or an electrochromic sheet or electrochromic glass, as long as it can dynamically change the overall transmittance of the optical waveguide component 10.

[0056] In one embodiment, a shielding layer is also included for shielding the entrance pupil region 100 and / or the dilation pupil region 200.

[0057] In this embodiment, the entrance pupil area 100 and the dilation pupil area 200 near the light engine 20 may leak light and affect its use. The locations where light leaks can be blocked with black material (i.e., the shielding layer) to ensure that light does not leak out and affect its use.

[0058] Combination Figure 9 and Figure 10 As shown, in one embodiment, the pupil-expanding grating unit and the exit pupil grating unit are independently configured grating units 11, used for pupil expansion and exit imaging respectively; or, the pupil-expanding grating unit and the exit pupil grating unit are integrated two-dimensional grating units, used for pupil expansion and exit imaging simultaneously.

[0059] In the embodiment, the pupil expanding grating unit and the exit pupil grating unit can be independent grating units 11, in which case the light waveguide assembly 10 is difficult to achieve a large screen ratio, but the placement position and ID design of the light engine 20 are more flexible;The pupil expanding grating unit and the exit pupil grating unit can also be two-dimensional grating units integrated, the light projected by the light engine 20 enters the entrance pupil area 100 and is coupled into the waveguide substrate 12 to propagate, and when entering the two-dimensional grating area 900, it expands the pupil and couples out the waveguide to image, in which case the light waveguide assembly 10 is easy to achieve a large screen ratio, but the placement position and ID design of the light engine 20 are more limited.

[0060] In summary, the AR light waveguide technology is applied to the transparent display, and the transparent display effect is achieved simply and efficiently by using the AR light waveguide technology, the transparency of the display is greatly improved, and the transparent display structure can realize transparent display without complex setting, that is, the complexity of the transparent display structure is reduced;At the same time, the imaging at infinity feature of the AR light waveguide technology can play a protective role for the eyes.

[0061] The embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments, and the same and similar parts between the embodiments can be referred to each other. It should be pointed out that, for ordinary skilled in the art, without departing from the principle of the present application, some improvements and modifications can be made to the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

[0062] It should be further noted that in the specification, the relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or includes not only those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or. Without more limitations, the element defined by the statement "including a" does not exclude the presence of another same element in the process, method, article or.

Claims

1. A transparent display based on AR optical waveguide technology, characterized in that, The light waveguide assembly, the light engine and the frame are included; the light waveguide assembly and the light engine are arranged in the frame; The light waveguide assembly includes a grating unit, the grating unit includes an entrance pupil grating unit, an expansion pupil grating unit and an exit pupil grating unit for forming an entrance pupil area, an expansion pupil area and an exit pupil area respectively, the light coupled out by the light engine propagates in the entrance pupil area, the expansion pupil area and the exit pupil area in turn for entrance pupil, expansion pupil and exit pupil, and is coupled out for imaging in the exit pupil area; The light waveguide assembly includes a waveguide substrate, the grating unit is arranged on one side or two sides of the waveguide substrate; the grating unit is made on the waveguide substrate by surface relief process or volume holographic exposure; The light waveguide assembly further includes a protective layer, the protective layer is attached to one side or two sides of the waveguide substrate, and is arranged spaced apart from the waveguide substrate; the gap between the protective layer and the waveguide substrate is less than or equal to 0.2mm; the protective layer and the waveguide substrate are fixed by support glue on the periphery; The light waveguide assembly further includes a transmittance adjustment layer, the transmittance adjustment layer is arranged on the opposite side of the waveguide substrate on the imaging side.

2. The transparent display based on AR optical waveguide technology according to claim 1, wherein, The transmittance adjustment layer is a liquid crystal layer, an electrochromic sheet or a photochromic sheet.

3. The transparent display based on AR optical waveguide technology according to claim 1, wherein, It further includes a shielding layer for shielding the entrance pupil area and / or the expansion pupil area.

4. The transparent display based on AR optical waveguide technology according to claim 1, wherein, The expansion pupil grating unit and the exit pupil grating unit are independently arranged grating units for expansion pupil and out-coupling imaging respectively; or the expansion pupil grating unit and the exit pupil grating unit are integrated two-dimensional grating units for expansion pupil and out-coupling imaging at the same time.

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