A waveguide lens and AR display device

Abstract

The present invention discloses a waveguide lens, including a waveguide substrate, a functional area arranged on the upper surface of the waveguide substrate or composed of a grating, the functional area including a coupling-in area for coupling image light into the waveguide substrate, a relay area for changing the direction of the image light transmitted through the coupling-in area, and a coupling-out area for projecting the image light transmitted from the relay area into the external space, the relay area including an intermediate turning area for transmitting the image light to both sides to increase the horizontal field of view and edge turning areas distributed on both sides of the intermediate turning area for transmitting the image light transmitted from the intermediate turning area to the coupling-out area. The present invention also discloses an AR display device, including the above-mentioned waveguide lens. Through the above-mentioned structure, symmetrical field of view expansion is achieved, the lack of unidirectional field of view expansion is compensated, and the multi-color diffraction efficiency balance in the exit pupil range is achieved.

Description

Technical Field

[0001] The present invention relates to the field of AR display technology, and in particular to a waveguide lens and an AR display device. Background Art

[0002] AR (Augmented Reality) technology is a new technology that "seamlessly" integrates real-world information and virtual-world information. It not only displays real-world information, but also displays virtual information at the same time. The two types of information complement and overlap each other. In visual augmented reality, users use helmet displays to overlap the real world with computer graphics, so they can see the real world around them.

[0003] For AR technology, since most of the user's field of vision presents real scenes, how to identify and understand real scenes and objects has become the primary task of AR perception and interaction. In addition, the resolution (clarity) and field of view (also known as field of view, referring to the range of vision) of AR technology will also become major technical challenges in the field of AR display.

[0004] Waveguide lenses are the key to making virtual objects more realistic and credible when superimposed on real scenes. In the prior art, in order to expand the field of view, it is expanded horizontally or vertically, such as Figure 1 As shown in the figure, the coupling-in area is transmitted to the turning area, forming an expansion of the field of view in the x direction, and the turning area is transmitted to the coupling-out area, forming an expansion of the field of view in the y direction, that is, double pupil expansion is achieved. However, in the process of transmitting from the coupling-in area to the turning area and from the turning area to the coupling-out area, only the first-order diffraction is used. In the case of multi-color diffraction, there is an unbalanced diffraction phenomenon in the field of view, resulting in obvious chromatic aberration, which affects the visual experience.

[0005] The preceding description is intended to provide general background information and does not necessarily constitute prior art. Summary of the invention

[0006] The object of the present invention is to provide a waveguide lens and an AR display device with reduced chromatic aberration.

[0007] The present invention provides a waveguide lens, comprising a waveguide substrate, and a functional area composed of gratings arranged on the surface of the waveguide substrate, wherein the functional area comprises an in-coupling area for coupling image light into the waveguide substrate, a relay area for changing the direction of the image light transmitted through the in-coupling area and the waveguide substrate, and an out-coupling area for projecting the image light transmitted through the relay area through the waveguide substrate into the external space of the waveguide lens, wherein the relay area comprises an intermediate turning area for transmitting the image light transmitted through the in-coupling area and the waveguide substrate to both sides, and edge turning areas distributed on both sides of the intermediate turning area for transmitting the image light transmitted from the intermediate turning area to the out-coupling area.

[0008] In one embodiment, the grating in the middle turning region is a two-dimensional array grating, so that the image light transmitted from the coupling-in region and the waveguide substrate is transmitted to the side turning regions on both sides.

[0009] In one embodiment, the two side turning regions are symmetrically distributed one-dimensional gratings, so that the image light transmitted from the middle turning region is transmitted to the outcoupling region.

[0010] In one embodiment, the gratings of the coupling-in region and the coupling-out region are both one-dimensional gratings, and the orientation angles of the gratings of the two are the same, the orientation angle of the grating of the edge turning region is different from the orientation angle of the grating of the coupling-in region, and the angle between the grating orientation of the edge turning region and the grating orientation of the coupling-in region is 45 degrees.

[0011] In one embodiment, the edge turning regions are symmetrically distributed on both sides of the middle turning region.

[0012] In one embodiment, the gratings of the coupling-in region and the coupling-out region include tilted gratings, rectangular gratings, blazed gratings, and volume gratings.

[0013] In one embodiment, the coupling-in region, the relay region and the coupling-out region are sequentially arranged in the same direction.

[0014] The present invention also provides an AR display device, comprising the waveguide lens.

[0015] In one embodiment, a frame is further included, wherein the frame is used to fix the left-right symmetrical waveguide lenses, and the left-right symmetrical waveguide lenses are used to match the left eye and the right eye respectively.

[0016] In one embodiment, two micro-projection devices and two image devices are arranged on the mirror frame, the two image devices are respectively connected to the two micro-projection devices, the two micro-projection devices are respectively connected to the left-right symmetrical waveguide lenses, the image devices output the image light to the micro-projection devices, and the micro-projection devices output the image light to the coupling-in area of ​​the waveguide lens.

[0017] The waveguide lens provided by the present invention realizes symmetrical field of view expansion through the middle turning zone for transmitting image light to both sides to achieve an increase in horizontal field of view and the side turning zones distributed on both sides of the middle turning zone for conducting the image light transmitted from the middle turning zone to the outcoupling area, thereby compensating for the lack of unidirectional field of view expansion, achieving balanced multi-color diffraction efficiency in the exit pupil range, and eliminating chromatic aberration effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of an existing waveguide lens image light transmission;

[0019] Figure 2 It is a schematic diagram of the structure of the waveguide lens of the present invention;

[0020] Figure 3 A schematic diagram of the azimuth angle and orientation angle formed when the image light is incident on the waveguide lens according to an embodiment of the present invention;

[0021] Figure 4 Schematic diagram of the transmission of image light in a waveguide lens according to an embodiment of the present invention;

[0022] Figure 5 It is a schematic diagram of the transmission of image light through the middle area in the waveguide substrate according to an embodiment of the present invention;

[0023] Figure 6 It is a schematic diagram showing the symmetrical diffraction of the waveguide lens according to an embodiment of the present invention;

[0024] Figure 7 Schematic diagram of the structure of an AR display device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0026] Please refer to Figures 2 to 6The waveguide lens provided in the embodiment of the present invention comprises a waveguide substrate 17 and a functional area composed of gratings arranged on the surface of the waveguide substrate 17. The functional area comprises an in-coupling area 11 for coupling image light into the waveguide substrate 17, a relay area 13 for changing the direction of the image light transmitted through the in-coupling area 11 and the waveguide substrate 17, and an out-coupling area 15 for projecting the image light transmitted from the relay area 13 through the waveguide substrate 17 into the external space of the waveguide lens. The relay area 13 comprises an intermediate turning area 131 for transmitting the image light to both sides to increase the horizontal field of view and an edge turning area 132 distributed on both sides of the intermediate turning area 131 for transmitting the image light transmitted from the intermediate turning area 131 to the out-coupling area 15.

[0027] In this embodiment, the waveguide lens 1 is a single waveguide lens 1 into which red, green and blue image lights are incident.

[0028] The coupling-in region 11, the relay region 13 and the coupling-out region 15 are arranged in sequence in the same direction. The gratings of the coupling-in region 11 and the coupling-out region 15 are both one-dimensional gratings, and the grating orientation angles (such as Figure 3 As shown, the image light K is incident on the grating 41, and the angle between it and the z-axis square is the incident angle α. The angle between the projection of the incident light on the xy plane and the x-axis is the azimuth angle θ, and the angle between the grating strips and the x-axis is the orientation angle φ).

[0029] Specifically, the gratings of the coupling-in region 11 and the coupling-out region 15 include tilted gratings, rectangular gratings, blazed gratings, and volume gratings.

[0030] The side turning areas 132 are symmetrically distributed on both sides of the middle turning area 131. The grating of the middle turning area 131 is a two-dimensional array grating, and the grating of the side turning area 132 is a one-dimensional grating. The two micro-array gratings of the middle turning area 131 are used to achieve the image light transmitted to the middle turning area 131 to be transmitted to both sides; at the same time, the horizontal field of view angle is also increased.

[0031] In this embodiment, the orientation angle of the grating in the edge turning region 132 is different from the orientation angle of the grating in the coupling-in region 11 .

[0032] Specifically, the grating orientation of the edge turning region 132 forms an angle with the grating orientation of the coupling-in region 11 , and the angle is 45 degrees.

[0033] Since the unidirectional transmission method only uses the positive first-order diffraction light or the negative first-order diffraction light, the symmetrical transmission method uses the positive first-order diffraction light and the negative first-order diffraction light generated at the same time, where the positive first-order diffraction light and the negative first-order diffraction light each undertake part of the transmission of the entire field of view. For example, the positive first-order diffraction light that transmits blue only occupies part of the entire field of view and cannot fully cover the entire field of view, resulting in an unbalanced display of blue in the entire field of view. By synchronously transmitting the blue negative first-order diffraction light, the missing blue image part of the entire field of view is compensated. A balanced display of blue in the entire field of view is achieved. The transmission principle of red and green is the same as that of blue.

[0034] Therefore, the diffraction efficiency of the grating at different incident angles is different. Each side turning area 132 can realize the display of most areas of the entire field of view. The design of the symmetrical side turning area 132 can achieve a composite field of view and realize the full display effect of the entire field of view, while making up for the lack of expansion of the one-way field of view and enhancing the balanced effect of the multi-color diffraction efficiency in the exit pupil range, thereby reducing chromatic aberration and eliminating the chromatic aberration effect. For example, the grating period of the side turning area 132 is 420nm, the height is 250nm, and the duty cycle is 0.3. Through the calculation of the diffraction angle, it is found that when the incident wavelength is 450nm, the incident angle that satisfies the first-order diffraction conduction of the waveguide lens 1 is -6.6° to 20°, and the incident angle that satisfies the negative first-order diffraction conduction is -20°-6.6°. Through symmetrical diffraction, full coverage of the field of view angle of -20°-20° can be achieved.

[0035] Please refer to Figure 7 The present invention also provides an AR display device, comprising the waveguide lens 1 and a lens frame 3. The lens frame 3 is used to fix the left-right symmetrical waveguide lens 1. The left-right symmetrical waveguide lens 1 is used to match the left eye and the right eye respectively.

[0036] In this embodiment, the AR display device further includes two micro-projection devices ( Figure 7 Not shown) and 2 image devices ( Figure 7 The two image devices are connected to two micro-projection devices respectively, and the two micro-projection devices are connected to the left-right symmetrical waveguide lens 1 respectively. The image device outputs the image light to the micro-projection device, and the micro-projection device outputs the image light to the coupling-in area 11 of the waveguide lens 1, and then diffracts and emits through the coupling-out area 15, and the output light is converged by the human eye to form an image, thereby realizing display.

[0037] In the accompanying drawings, the sizes and relative sizes of layers and regions are exaggerated for clarity. It should be understood that when an element, such as a layer, region, or substrate, is referred to as being "formed on," "disposed on," or "located on" another element, the element may be disposed directly on the other element, or there may be intervening elements. Conversely, when an element is referred to as being "formed directly on" or "disposed directly on" another element, there are no intervening elements.

[0038] In this document, unless otherwise specified or limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0039] In this document, the directions or positional relationships indicated by terms such as "up", "down", "front", "back", "left", "right", "top", "bottom", "inside", "outside", "vertical", and "horizontal" are based on the directions or positional relationships shown in the accompanying drawings and are only for the clarity of expressing the technical solutions and the convenience of description, and therefore should not be understood as limitations of the present invention.

[0040] As used herein, unless otherwise specified, “plurality” or “several” means two or more.

[0041] In this document, the terms "comprises," "comprising," or any other variations thereof, are intended to cover a non-exclusive inclusion of elements other than those listed and may also include additional elements not expressly listed.

[0042] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A waveguide lens, characterized in that: The invention comprises a waveguide substrate and a functional area composed of gratings arranged on the surface of the waveguide substrate, wherein the functional area comprises an in-coupling area for coupling image light into the waveguide substrate, a relay area for changing the direction of the image light transmitted through the in-coupling area and the waveguide substrate, and an out-coupling area for projecting the image light transmitted through the relay area through the waveguide substrate into the external space of the waveguide lens, wherein the relay area comprises an intermediate turning area for transmitting the image light transmitted through the in-coupling area and the waveguide substrate to both sides and edge turning areas distributed on both sides of the intermediate turning area for transmitting the image light transmitted from the intermediate turning area to the out-coupling area; the edge turning areas are symmetrically distributed on both sides of the intermediate turning area; the in-coupling area, the relay area and the out-coupling area are arranged in sequence in the same direction; and the grating of the intermediate turning area is a two-dimensional array grating.

2. The waveguide lens according to claim 1, wherein: The turning areas at both sides are symmetrically distributed one-dimensional gratings, so that the image light transmitted from the middle turning area is transmitted to the outcoupling area.

3. The waveguide lens according to claim 2, wherein: The gratings in the coupling-in region and the coupling-out region are both one-dimensional gratings, and their grating orientation angles are the same. The orientation angle of the grating in the edge turning region is different from the orientation angle of the grating in the coupling region, and the angle between the grating orientation in the edge turning region and the grating orientation in the coupling region is 45 degrees.

4. The waveguide lens according to claim 1, wherein: The gratings of the coupling-in region and the coupling-out region include tilted gratings, rectangular gratings, blazed gratings, and volume gratings.

5. An AR display device, characterized in that: The invention comprises a waveguide lens as claimed in any one of claims 1 to 4.

6. The AR display device according to claim 5, characterized in that: It also includes a frame, which is used to fix the left-right symmetrical waveguide lenses, and the left-right symmetrical waveguide lenses are used to match the left eye and the right eye respectively.

7. The AR display device according to claim 6, wherein: It also includes two micro-projection devices and two image devices, the two image devices are respectively connected to the two micro-projection devices, the two micro-projection devices are respectively connected to the left-right symmetrical waveguide lenses, the image devices output the image light to the micro-projection devices, and the micro-projection devices output the image light to the coupling-in area of ​​the waveguide lenses.

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