Background
Augmented Reality (AR) technology is a new technology for seamlessly integrating real world information and virtual world information, and is a technology for overlaying entity information (visual information, sound, taste, touch and the like) which is difficult to experience in a certain time space range of the real world originally by simulating and simulating through a photoelectric information technology, applying virtual information to the real world and sensing by human senses, so that the sensory experience beyond the Reality is achieved. Real environment and virtual object are superimposed on the same picture or space in real time and exist simultaneously, and high-reality virtual-real fusion is realized. Among the features of the AR system: and additionally positioning the virtual object in the three-dimensional scale space.
Most of the current mainstream near-eye augmented reality display devices adopt the optical waveguide principle. The publication number is: 106338832A discloses a monolithic holographic diffractive light waveguide lens, which comprises a layer of optical waveguide medium and a first functional area, a second functional area and a third functional area arranged on the optical waveguide; the external image light beam is incident through the first functional area, coupled into the optical waveguide, propagates to the second functional area under the action of total reflection of the optical waveguide, is diffracted through the second functional area, continues to propagate to the third functional area under the action of total reflection of the optical waveguide, and finally is diffracted through the third functional area to emit the image light beam to an external space.
However, in order to satisfy the requirement of total reflection transmission of light in the optical waveguide, the light incident on the first functional region needs to be incident in a large range with respect to the normal of the surface of the optical waveguide, and accordingly, the emergent angle is also emitted in a large range with respect to the normal of the surface of the optical waveguide. At this time, due to the limitation of the existing optical waveguide lens, the deviation of the positive angle of the image viewed by human eyes is large, and the image display effect is poor; and the requirement of a large range of incident light results in a complex structure of the front-end optical system.
Disclosure of Invention
The application provides a display device and an optical waveguide lens, which can solve the limitation of the existing optical waveguide lens, the deviation positive angle of an image watched by human eyes is large, and the image display effect is poor; and the requirement of a large range of incident light causes a problem of a complicated structure of the front-end optical system. The application provides the following technical scheme:
in a first aspect, there is provided a display device, comprising:
an optical waveguide lens comprising a plurality of functional areas, the plurality of functional areas comprising light incoupling areas;
the transparent lens is attached to the substrate corresponding to the light coupling-in area in the optical waveguide lens; and light is refracted by the transparent lens, then enters the optical waveguide lens, is coupled into the optical waveguide lens through the light coupling-in area and is transmitted by total reflection.
Optionally, the incident angle of the light ray to the transparent lens is smaller than the critical angle of total reflection.
Optionally, the transparent lens is a transparent prism whose one surface is attached to the substrate corresponding to the light coupling-in area.
Optionally, the refractive index range of the transparent prism is the same as the refractive index range of the optical waveguide lens.
Optionally, the transparent prism has a refractive index in the range of [1.4, 2 ].
Optionally, the transparent prism is a triangular prism.
Optionally, the transparent lens is seamlessly attached to the substrate corresponding to the light coupling-in area.
Optionally, the plurality of functional areas are located on an upper surface of the optical waveguide lens; or, the lower surface of the optical waveguide lens is positioned; or one part is positioned on the upper surface of the optical waveguide lens, and the other part is positioned on the lower surface of the optical waveguide lens.
Optionally, each functional region comprises at least one building block pixel consisting of a periodic nanograting.
In a second aspect, there is provided an optical waveguide lens comprising a plurality of functional areas; the plurality of functional regions includes a light incoupling region; the position corresponding to the light coupling-in area is provided with a transparent lens which is arranged in a protruding way; and the light is refracted by the transparent lens, then enters the light coupling-in area, and is coupled into the optical waveguide lens through the light coupling-in area for total reflection transmission.
The beneficial effect of this application lies in: the transparent lens is attached to the substrate corresponding to the light coupling-in area of the optical waveguide lens, and light is refracted by the transparent lens and then enters the optical waveguide lens; at this time, the transparent lens can receive the light ray with a small-angle incident angle before the light ray is incident to the light ray coupling-in area, and refract the light ray into a large-angle incident to the light ray coupling-in area, so that the light ray can be totally reflected and transmitted in the optical waveguide lens after being coupled by the light ray coupling-in area; the limitation of the existing optical waveguide lens can be solved, the deviation of the positive angle of an image watched by human eyes is large, and the image display effect is poor; the requirement of large-range incident light causes the problem of complex structure of the front-end optical system; because the light only needs to be incident within a small angle range, the structural complexity of the front-end optical system can be reduced; meanwhile, the refraction effect of the transparent lens can also improve the condition that the positive angle of an image formed by the light coupled out by the optical waveguide lens deviates from the condition that human eyes watch the image is larger.
The foregoing description is only an overview of the technical solutions of the present application, and in order to make the technical solutions of the present application more clear and clear, and to implement the technical solutions according to the content of the description, the following detailed description is made with reference to the preferred embodiments of the present application and the accompanying drawings.
Detailed Description
The following detailed description of embodiments of the present application will be described in conjunction with the accompanying drawings and examples. The following examples are intended to illustrate the present application but are not intended to limit the scope of the present application.
Fig. 1 is a schematic structural diagram of an optical waveguide lens provided in an embodiment of the present application, and as shown in fig. 1, the optical waveguide lens includes a plurality of functional regions (11, 12, and 13).
Optionally, the plurality of functional areas are located on the upper surface of the optical waveguide lens; or, the lower surface of the optical waveguide lens; or one part is positioned on the upper surface of the optical waveguide lens, and the other part is positioned on the lower surface of the optical waveguide lens.
Optionally, each functional region comprises at least one building block pixel consisting of a periodic nanograting.
Illustratively, the plurality of functional regions includes a light incoupling region 11. The light incoupling area 11 is used for incoupling light into the optical waveguide lens, and the incoupling light needs to satisfy the condition of total reflection transmission in the optical waveguide lens. Optionally, the light incoupling region 11 includes 3 kinds of structural unit pixels, and the 3 kinds of structural unit pixels are respectively used for coupling light of three color images of red, green and blue. In one example, the period of the periodic nano-grating of the pixel of the structural unit in the light coupling-in region 11 is 200-600nm, the duty ratio is 0.1-0.7, and the depth is 100-500 nm.
Optionally, the plurality of functional areas comprises a light outcoupling area 12. The light outcoupling region 12 serves to couple light propagating in the optical waveguide lens out of the optical waveguide lens. The light coupling-out region 12 includes 3 kinds of structural unit pixels, and the 3 kinds of structural unit pixels are respectively used for coupling the light of the three-color image of red, green and blue. In one example, the period of the periodic nano-grating of the structural unit pixel in the light-incoupling region 12 is 200-600nm (the same as the period of the periodic nano-grating of the structural unit pixel in the light-incoupling region 11), the duty ratio is 0.1-0.7, and the depth is 100-500 nm.
Optionally, the plurality of functional regions comprises a ray-turning region 13. The light turning region 13 is used for turning the light coupled from the light-in region 11 to the light-out region 12. The light turning region 13 includes 3 kinds of structural unit pixels, and the 3 kinds of structural unit pixels are respectively used for coupling the light of the red, green and blue three-color images. In one example, the period of the periodic nano-grating of the structural unit pixel in the light turning region 13 is between 150-500nm, the duty ratio is between 0.1-0.7, and the depth is between 100-500 nm.
Schematically, the orientation of the periodic nanograting in the light turning region 13 is 45 ° to the orientation of the periodic nanograting in the light incoupling region 11; the orientation of the periodic nanograms in the light outcoupling region 12 is 90 ° to that of the periodic nanograms in the light incoupling region 11.
In the optical waveguide lens shown in fig. 1, the light incoupling region 11 has a broadband diffraction function. The diffraction light of the three color images of red, green and blue needs to satisfy the condition of total reflection in the optical waveguide lens, so that the light coupled into the optical waveguide lens through the light coupling-in area 11 can be transmitted in the optical waveguide lens by total reflection, and is diffracted to the light coupling-out area 12 through the light turning area 13; the light of the three-color image is coupled out of the optical waveguide lens and transmitted to human eyes after being diffracted by the light coupling-out area 12, and the color augmented reality display is realized through the synthesis of the human eyes.
It should be noted that fig. 1 only illustrates that the optical waveguide lens includes 3 functional regions, and in actual implementation, the number of the functional regions may be 2 or 3 or more, and the number of the functional regions is not limited in this embodiment.
For the optical waveguide lens shown in fig. 1, the diffracted light generated by the incident light diffracted by the light coupling-in area 11 needs to satisfy the requirement of total internal reflection of the optical waveguide lens, and the light needs to be incident at a large angle relative to the normal of the surface of the optical waveguide lens, and at this time, the light generated by the light coupling-in area 11 can be transmitted by total reflection in the optical waveguide lens. The period and the angle of view of the periodic nano-grating in the light incoupling region 11 and the wavelength of incident light need to satisfy Λ 1 ═ λ/(1+ sin FOV/2). Where Λ 1 is the period of the periodic nanograting in the light incoupling region 11, FOV is the field of view, and λ is the wavelength of incident light.
Referring to fig. 2, it is assumed that light is incident at two critical angles (shown as a light path shown by a solid line and a light path shown by a dotted line, respectively) capable of being totally reflected and transmitted in the optical waveguide lens, and an angle between the two critical angles is 50 °. Since the light rays constituting the image are incident into the optical waveguide lens at the same diffraction angle when entering the light ray coupling-in area 11, and are propagated under the total reflection condition, the light rays are emitted at an angle parallel to the incident light rays when being output, and the image can be displayed completely, the field of view constituted by the light rays coupled out from the light ray coupling-out area 12 is 50 °.
When the light is output from the light coupling-out area 12, because the total reflection incident angles are consistent, and the periods of the periodic nano gratings of the light coupling-in area 11 and the light coupling-out area 12 are consistent, at each total reflection exit point, the light is parallel to the original light, which causes that the image formation has a certain deviation at different exit pupil positions, and when the image formation surface is less than 1 meter, the positive angle of the image formed by the emergent light when the image is viewed by human eyes is larger. In addition, the included angle between the two critical angles is large, and the structure of the front-end optical system is complicated due to the requirement of large-range incident light.
Based on the above technical problem, in the optical waveguide lens, the transparent lens is introduced at a position corresponding to the light coupling-in area 11, and the transparent lens is configured to receive the light at a small incident angle before the light enters the light coupling-in area 11, and refract the light to enter the light coupling-in area 11 at a large incident angle, so that the light can be transmitted by total reflection in the optical waveguide lens after being coupled by the light coupling-in area 11. Because the light only needs to be incident within a small angle range, the structural complexity of the front-end optical system can be reduced; meanwhile, the transparent lens can also improve the condition that the positive angle of an image formed by light coupled out by the optical waveguide lens deviates from that when the image is watched by human eyes is larger.
Fig. 3 is a schematic structural diagram of a display device according to an embodiment of the present application, and as shown in fig. 3, the display device at least includes: an optical waveguide lens 1 and a transparent lens 2.
The optical waveguide lens 1 includes a plurality of functional regions, and the plurality of functional regions includes a light coupling-in region 11, and the light coupling-in region 11 is used for coupling light into the optical waveguide lens and performing total reflection transmission in the optical waveguide lens. The optical waveguide lens 1 may be the optical waveguide lens shown in fig. 1.
The transparent lens 2 is attached to the substrate corresponding to the light input region 11 of the optical waveguide lens 1. The light is refracted by the transparent lens 2 and then enters the optical waveguide lens 1, and is coupled into the optical waveguide lens 1 through the light coupling-in area 11 for total reflection transmission.
The transparent lens 2 is used for refracting the light before the light enters the optical waveguide lens, and the refracted light is coupled by the light coupling area 11 to meet the requirement of total reflection transmission in the optical waveguide lens 1. Alternatively, in order to enable the transparent lens 2 to refract the light, the incident angle of the light to the transparent lens 2 is smaller than the critical angle at which total reflection occurs.
Optionally, the normal line of the surface of the transparent lens 2 has a plurality of angles, so that light rays with different angles can be refracted through the adaptive positions in the transparent lens 2, so that the refracted light rays can meet the requirement of total reflection transmission in the optical waveguide lens 1 after being coupled through the light ray coupling-in area 11.
In one example, the transparent lens 2 is a transparent prism having one surface attached to a substrate corresponding to the light-incoupling area 11. At this time, the transparent prism has at least two side surfaces which are not attached to the optical waveguide lens, and the normal line of each side surface is different.
Alternatively, the refractive index range of the transparent prism is the same as that of the optical waveguide lens 1. Thus, the light refracted by the transparent prism can be directly incident to the optical waveguide lens 1 without being bent, and the complexity of calculating the incident angle of the light can be reduced. Such as: the transparent prism has a refractive index in the range of
[1.4,2]。
Optionally, the transparent lens is seamlessly attached to the substrate corresponding to the light coupling-in area, so as to ensure that the light refracted by the transparent prism can be directly incident to the optical waveguide lens 1 without bending.
Referring to fig. 3, it is assumed that light is incident at two critical angles (a light path shown by a solid line and a light path shown by a broken line in fig. 3) at which total reflection can be performed in the optical waveguide lens 1, respectively, and an included angle between the two critical angles is 11.3 °. After being adjusted by the transparent lens 2, the angle of the adjusted light ray entering the optical waveguide lens is increased, and the light ray is coupled into the optical waveguide lens 2 and meets the condition of total reflection transmission. Since the wavelength of the incident light and the period of the periodic nano-grating in the light coupling-in region 11 are not changed, the field of view of the light coupled out from the light coupling-out region 12 is still 50 °. At this time, the case where the image composed of the light coupled out from the light coupling-out area 12 deviates from the positive angle when the image is viewed by the human eye is also improved due to the refraction action of the transparent lens.
In fig. 3, the transparent prism is illustrated as a triangular prism, but in actual implementation, the transparent prism may be a quadrangular prism, a pentagonal prism, or the like, and the specific shape of the transparent prism is not limited in this embodiment. In addition, in fig. 3, an included angle between two side surfaces of the prism, which are not attached to the optical waveguide lens, is 90 degrees, when the prism is actually implemented, the included angle may also be set to other angles according to an angle of an incident light ray, only a requirement that the adjusted light ray is coupled into the optical waveguide lens at an incident angle greater than or equal to a preset angle is required to be satisfied, and a value of the included angle is not limited in this embodiment.
In another example, the transparent lens 2 is a curved transparent mirror attached to a substrate corresponding to the light-coupling-in area 11, such as: a lens formed by half of a cylinder. Of course, the transparent lens 2 can also be implemented in other shapes, such as: irregular shape, etc., and the implementation of the transparent lens 2 is not limited in this embodiment.
Optionally, in order to further improve the situation that the image formed by the light coupled out from the light coupling-out area 12 deviates from the positive angle when the human eye views the image, another transparent lens may be attached to the substrate corresponding to the light coupling-out area 12.
In summary, in the display device provided in this embodiment, the transparent lens is attached to the substrate corresponding to the light-coupling-in area of the optical waveguide lens, and the light is refracted by the transparent lens and then enters the optical waveguide lens; at this time, the transparent lens can receive the light ray with a small-angle incident angle before the light ray is incident to the light ray coupling-in area, and refract the light ray into a large-angle incident to the light ray coupling-in area, so that the light ray can be totally reflected and transmitted in the optical waveguide lens after being coupled by the light ray coupling-in area; the limitation of the existing optical waveguide lens can be solved, the deviation of the positive angle of an image watched by human eyes is large, and the image display effect is poor; the requirement of large-range incident light causes the problem of complex structure of the front-end optical system; because the light only needs to be incident within a small angle range, the structural complexity of the front-end optical system can be reduced; meanwhile, the refraction effect of the transparent lens can also improve the condition that the positive angle of an image formed by the light coupled out by the optical waveguide lens deviates from the condition that human eyes watch the image is larger.
Optionally, in another implementation, the transparent lens is integrated into the optical waveguide lens, in which case the optical waveguide lens includes a plurality of functional areas; the plurality of functional regions includes a light incoupling region; the position corresponding to the light coupling-in area is provided with a transparent lens which is arranged in a protruding way; the light is refracted by the transparent lens, then enters the light coupling-in area, and is coupled into the optical waveguide lens through the light coupling-in area for total reflection transmission.
At this time, the related description of the transparent lens refers to the above embodiments, and the description of the embodiment is omitted here.
Optionally, the present application further provides a three-dimensional display system, where the display device according to the above embodiment is installed in the three-dimensional display system; alternatively, the transparent lens described in the above embodiments. Of course, the three-dimensional display system may also include other components, such as: the front-end optical system (e.g., projection system), power supply module, communication module, etc., and the detailed description thereof is omitted here.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.