Optical waveguide display structure
By using pupil dilated components including flat panels, microprism arrays and spectroscopic prism arrays in the optical waveguide display system, the existing optical waveguide display system has solved the problems of large size, large weight and complex processing, and the effects of miniaturization, lightweight and full color display are achieved.
Patent Information
- Application Number
- CN202510334832.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-20
- Publication Date
- 2025-05-30
AI Technical Summary
When existing optical waveguide display systems achieve large eye movement range and large field of view angle, the system volume and weight are relatively large, making it difficult to achieve miniaturization and lightweight. At the same time, diffraction optical waveguides are difficult to achieve full color display, and the processing of geometric optical waveguides is complex and costly.
An optical waveguide display structure including a pupil dilated assembly is adopted. The pupil dilated assembly is composed of a flat plate, a microprism array and a spectroscopic prism array. Through the cooperation of the first reflective surface, a spectroscopic film, a microprism unit and a spectroscopic prism unit, the pupil dilation and gap of the light beam are achieved to ensure beam uniformity and gap-free.
The optical waveguide display structure is miniaturized, lightweighted and full-color display. The beam after pupil dilated has no interval, and the overall structure is simple and the size is small.
Smart Images
Figure CN120065537A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of displays, and more particularly to a waveguide display structure. Background Art
[0002] A Head-Up Display (HUD) is a type of airborne and vehicle-mounted instrument device with augmented reality capabilities. It projects driving parameters, navigation information, etc. in the form of images and characters onto the front of the driver through an optical system, enabling the driver to obtain various information from the aircraft or vehicle while observing the driving environment.
[0003] With the rapid development of the automotive industry, the requirements for the integration of vehicle internal systems have increased significantly, and the requirements for the lightweight, miniaturization, and display effect of HUD systems have become higher and higher. Traditional in-vehicle HUD systems are mainly designed according to the off-axis reflection type structure. The image displayed by the light source is first projected onto the windshield or auxiliary display screen through the off-axis mirror system, and then reflected into the human eye. If this design scheme is used to achieve a large eye movement range and a large field of view, the volume of the mirror and the overall volume and weight of the system will be very large, and it is impossible to achieve the miniaturization and lightweight of the system, and there is not enough assembly space inside the vehicle. The waveguide technology can expand a coupled-in light beam into several coupled-out light beams in a glass plate (this process is called pupil expansion). Applying it to the in-vehicle head-up display system can effectively reduce the volume of the optical engine system. And the light beam after pupil expansion is generally parallel light, which is helpful for the human eye to observe, and the angle of the light beam before and after pupil expansion does not change, ensuring that the image will not be distorted. Therefore, the HUD system based on waveguide is widely regarded as an important direction for the next generation of HUD systems by the industry.
[0004] The waveguide display system can be divided into a geometric waveguide and a diffractive waveguide according to the type of waveguide used. The diffractive waveguide realizes the pupil expansion of the light beam through diffractive elements (such as liquid crystal gratings, holographic gratings, etc.), but the diffraction angle and diffraction efficiency of the diffractive elements are very sensitive to the light wavelength, and it is difficult to achieve full-color display.
[0005] Geometric optical waveguides can be divided into transmissive-reflective film optical waveguides and microprism optical waveguides according to different coupling output optical elements. Among them, the transmissive-reflective film optical waveguide uses multiple partially reflective mirrors (PRMs) to control the coupled output of light beams. Since each partially reflective mirror needs to be embedded inside the waveguide plate, in actual processing, it needs to be fabricated in blocks first and then glued into a whole. The processing time is long and the cost is high. It is difficult to control the flatness of the overall optical waveguide during multiple gluing processes, and mass production is limited. The microprism waveguide controls the coupled output of light beams through a microprism array, and controls the ratio of reflected and transmitted light by controlling the different density arrangements of the microprism array, thereby controlling the uniformity of the outgoing light, but this will cause unnecessary gaps in the light beam. Summary of the Invention
[0006] In order to overcome the deficiencies of the prior art, one of the objectives of the present invention is to provide an optical waveguide display structure with a simple structure, small volume, and no gaps in the light beam.
[0007] One of the objectives of the present invention is achieved by adopting the following technical solutions:
[0008] An optical waveguide display structure includes a pupil expansion component. The pupil expansion component includes a flat plate. The flat plate includes a first plane, a second plane parallel to the first plane, and a first reflecting surface. The first reflecting surface connects the first plane and the second plane, and the first reflecting surface is inclined. The pupil expansion component further includes a microprism array and a beam splitting prism array. The microprism array is arranged along the first plane, and a beam splitting film is provided at the contact between the first plane and the microprism array. The microprism array includes multiple microprism units, and each microprism unit is provided with a second reflecting surface. The beam splitting prism array is arranged along the second plane, and the beam splitting prism array includes multiple beam splitting prism units. Each beam splitting prism unit is provided with a beam splitting surface and a third reflecting surface. The projections of the beam splitting surface and the third reflecting surface on the second plane are continuous. After light enters the pupil expansion component, it is reflected by the first reflecting surface to change the angle and propagate in the flat plate in a total internal reflection manner at a large angle. After the light contacts the beam splitting film, a part of the light passes through the first plane and is reflected by the second reflecting surface of the microprism unit, and then enters the flat plate again through the first plane at a small incident angle and exits through the second plane. Other light beams continue to propagate backward and exit through the second plane. The light exiting through the second plane is split by the beam splitting surface of the beam splitting prism unit, and part of it is directly emitted from the beam splitting surface. The split light is reflected by the third reflecting surface and then emitted, evenly filling the gaps in the discontinuous part of the light beam.
[0009] Further, the beam splitting ratio of the beam splitting film gradually decreases from near to far along the light beam propagation direction.
[0010] Further, the transmittance of the beam splitting film where N is the number of pupil expansion times, and i = 0, 1, 2, …, N - 1.
[0011] Further, each of the micro prism units is in the shape of a triangular pyramid.
[0012] Further, the second reflection surface is an inclined surface, and the angle of the second reflection surface is the same as the angle of the first reflection surface.
[0013] Further, a plurality of the micro prism units are closely arranged.
[0014] Further, the beam splitting surface is parallel to the third reflection surface.
[0015] Further, a plurality of the beam splitting prism units are closely arranged.
[0016] Further, the beam splitting surface is formed by plating a 50%:50% beam splitting film on an inclined surface.
[0017] Further, the beam splitting prism unit is in the shape of a right trapezoid.
[0018] Compared with the prior art, after the light of the optical waveguide display structure of the present invention enters the pupil expansion component, it is reflected by the first reflection surface to change the angle and propagate in the flat plate in a total reflection manner at a large angle. After the light contacts the beam splitting film, a part of the light passes through the first plane and is reflected by the second reflection surface of the micro prism unit, and then enters the flat plate again through the first plane at a small incident angle and exits through the second plane. Other light beams continue to propagate backward and exit through the second plane. After the light exiting through the second plane is split by the beam splitting surface of the beam splitting prism unit, part of it directly exits from the beam splitting surface, and the split light is reflected by the third reflection surface and then exits, evenly filling the gaps in the discontinuous part of the light beam. Through the above design, there is no interval in the pupil-expanded light beam, and the overall structure of the optical waveguide display structure is simple and small in volume. Description of the Drawings
[0019] Figure 1 is a structural diagram of the optical waveguide display structure of the present invention;
[0020] Figure 2 is Figure 1 the optical path diagram of the pupil expansion component of the optical waveguide display structure of
[0021] Figure 3 is Figure 2 the optical path diagram of the beam splitting prism array of
[0022] Figure 4 is the effect diagram when the pupil expansion component does not include a beam splitting prism;
[0023] Figure 5 is the effect diagram when the pupil expansion component includes a beam splitting prism.
[0024] In the figure: 10, light source; 20, collimating component; 30, pupil-expanding component; 31, flat plate; 310, first reflecting surface; 312, first plane; 311, second plane; 32, micro prism array; 320, second reflecting surface; 33, beam splitting prism array; 330, first lens body; 331, second lens body; 332, third lens body; 333, fourth lens body; 334, beam splitting surface; 335, third reflecting surface. Specific embodiments
[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.
[0026] It should be noted that when a component is referred to as being "fixed to" another component, it can be directly on the other component or there may also be another intermediate component through which it is fixed. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may also be another intermediate component at the same time. When a component is considered to be "disposed on" another component, it can be directly disposed on the other component or there may also be another intermediate component at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.
[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. The terms used in the description of the present invention herein are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.
[0028] Please refer to Figure 1 A waveguide display structure of the present application includes a light source 10, a collimating component 20 and a pupil-expanding component 30.
[0029] The light source 10 serves as a phase source and is used to output light.
[0030] The collimating component 20 is located between the light source 10 and the pupil-expanding component 30 and is used to collimate the light of the light source 10 so that the light entering the pupil-expanding component 30 is collimated light.
[0031] Please continue to refer to Figure 2 and Figure 3, the pupil expansion component 30 includes a flat plate 31, a micro prism array 32, and a beam splitting prism array 33.
[0032] The flat plate 31 is made of glass. The flat plate 31 includes a first plane 312, a second plane 311, and a first reflecting surface 310. The first plane 312 is parallel to the second plane 311, and the first reflecting surface 310 connects the first plane 312 and the second plane 311. The first reflecting surface 310 is located at the edge on one side of the flat plate 31. The first reflecting surface 310 is inclined and faces the collimating component 20. The first reflecting surface 310 is inclined towards the other side of the flat plate 31, so that the light propagates along the length direction of the flat plate 31. The reflection ratio of the first reflecting surface 310 is close to 100%. By coating a reflective film, the incident light beam at a small angle can be coupled into the flat plate 31 at a large angle so that it can propagate in the flat plate 31 by total reflection.
[0033] The first plane 312 is in contact with the micro prism array 32. A beam splitting film is provided at the contact between the first plane 312 and the micro prism array 32. The beam splitting film splits the incident light at a large angle according to a certain ratio, and the transmittance of the incident light at a small angle is ≥90%. Part of the light propagating along the length direction of the flat plate 31 passes through the first plane 312, is reflected by the micro prism array 32, enters the flat plate 31 again through the first plane 312 at a small incident angle, and exits through the second plane 311. Other light beams continue to propagate backward, so as to achieve pupil expansion. In order to achieve uniform distribution of the energy of the pupil-expanded light beam in different regions and control the uniformity of the illuminance of the pupil-expanded light beam, the energy ratio of the light beam passing through and reflecting is controlled by adjusting the reflectivity of the beam splitting film in different regions along the light propagation direction. The beam splitting ratio of the beam splitting film gradually decreases from near to far along the light propagation direction. Specifically, the transmittance of the beam splitting film where N is the number of pupil expansion times, and i = 0, 1, 2, …, N - 1.
[0034] An antireflection film is coated at the contact between the second plane 311 and the beam splitting prism array 33.
[0035] The micro prism array 32 includes a plurality of micro prism units, and the plurality of micro prism units are closely arranged. Several micro prism units form a region, and this region realizes one-time pupil expansion. The micro prism array 32 is glued to the first plane 312. Each micro prism unit is in the shape of a triangular pyramid. Each micro prism unit is provided with a second reflecting surface 320. The second reflecting surface 320 is an inclined surface, and the angle of the second reflecting surface 320 is the same as the angle of the first reflecting surface 310. The refractive index of the flat plate 31 is close to the refractive index of the micro prism unit, ensuring that the angle of the pupil-expanded light beam is close to the angle of the original incident light beam. In this embodiment, the cross section of the micro prism unit is a right triangle. The second reflecting surface 320 is the hypotenuse of the right triangle. There will be gaps in the light reflected by the micro prism array 32, as Figure 4 shown, so the beam splitting prism array 33 is needed to make up for it.
[0036] The beam splitting prism array 33 includes a plurality of beam splitting prism units which are closely arranged. The beam splitting prism array 33 is glued to the second plane 311. Each beam splitting prism unit is in the shape of a right trapezoid. Each beam splitting prism unit is provided with a beam splitting surface 334 and a third reflection surface 335. Both the beam splitting surface 334 and the third reflection surface 335 are inclined surfaces. The beam splitting surface 334 is parallel to the third reflection surface 335. The projections of the beam splitting surface 334 and the third reflection surface 335 on the second plane 311 are continuous to avoid gaps after beam splitting. Specifically, in this embodiment, the beam splitting prism array 33 includes a first prism body 330, a second prism body 331, a third prism body 332 and a fourth prism body 333. The first prism body 330, the second prism body 331 and the third prism body 332 are all right triangles, and the fourth prism body 333 is rectangular. The beam splitting surface 334 is arranged between the first prism body 330 and the second prism body 331. The beam splitting surface 334 is realized by coating a beam splitting film on the contact surface between the first prism body 330 and the second prism body 331. The beam splitting ratio of the beam splitting film is 50%:50%. The beam splitting ratio refers to the reflection ratio to the transmission ratio. The third reflection surface 335 is arranged on the hypotenuse of the third prism body 332. Through the beam splitting of the beam splitting prism array 33, the gaps of the light reflected by the micro prism array 32 are filled, as Figure 5 shown.
[0037] When using the optical waveguide display structure, the light emitted by the light source 10 enters the pupil expanding component 30 after being collimated by the collimating component 20. After entering the pupil expanding component 30, the light is reflected by the first reflection surface 310 and changes its angle to propagate in the flat plate 31 in a total internal reflection manner at a large angle. When the light touches the beam splitting film on the first plane 312, a part of the light passes through the first plane 312 and is reflected by the second reflection surface 320 of the micro prism unit of the micro prism array 32, and then enters the flat plate 31 again at a small incident angle and exits through the second plane 311. Other light beams continue to propagate backward. The light exiting through the second plane 311 is split by the beam splitting surface 334 of the beam splitting prism unit of the beam splitting prism array 33. Part of the light is directly emitted from the beam splitting surface 334, and the split light is emitted after being reflected by the third reflection surface 335, evenly filling the gaps in the discontinuous part of the light beam. Through the above design, there are no intervals in the beam after pupil expansion, and the overall structure of the optical waveguide display structure is simple and small in size.
[0038] The above embodiments only represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can be made. These are all equivalent modifications and evolutions made to the above embodiments based on the essential technology of the present invention, and these all belong to the protection scope of the present invention.
Claims
1. An optical waveguide display structure, comprising a pupil expansion component, wherein the pupil expansion component comprises a flat plate, wherein the flat plate comprises a first plane and a second plane parallel to the first plane, wherein: The flat plate further includes a first reflecting surface, the first reflecting surface connects the first plane and the second plane, and the first reflecting surface is tilted. The pupil expansion assembly further includes a microprism array and a beam splitter prism array, the microprism array is arranged along the first plane, and a beam splitter film is arranged at the contact between the first plane and the microprism array. The microprism array includes a plurality of microprism units, each of which is provided with a second reflecting surface. The beam splitter prism array is arranged along the second plane, the beam splitter prism array includes a plurality of beam splitter prism units, each of which is provided with a beam splitter surface and a third reflecting surface, and the beam splitter surface and the third reflecting surface are provided. The projection of the surface on the second plane is continuous. After entering the pupil expansion component, the light is reflected by the first reflection surface to change the angle and propagates in the flat plate in a large-angle total reflection manner. After the light contacts the dichroic film, a part of the light passes through the first plane and is reflected by the second reflection surface of the microprism unit, and then passes through the first plane again at a small incident angle to enter the flat plate and is emitted through the second plane. The other light beams continue to propagate backward. After the light emitted through the second plane is split by the splitting surface of the splitting prism unit, part of it is directly emitted from the splitting surface, and the split light is reflected by the third reflection surface and then emitted, so as to evenly fill the gaps in the discontinuous part of the light beam.
2. The optical waveguide display structure according to claim 1, characterized in that: The light splitting ratio of the light splitting film gradually decreases from near to far along the propagation direction of the light beam.
3. The optical waveguide display structure according to claim 2, characterized in that: The transmittance of the beam splitting film Wherein, N is the number of pupil dilations, i=0, 1, 2, ..., N-1.
4. The optical waveguide display structure according to claim 1, characterized in that: Each of the micro-prism units is in a triangular pyramid shape or a trapezoidal shape.
5. The optical waveguide display structure according to claim 4, characterized in that: The second reflecting surface is an inclined surface, and the angle of the second reflecting surface is the same as the angle of the first reflecting surface.
6. The optical waveguide display structure according to claim 1, characterized in that: A plurality of the microprism units are closely arranged.
7. The optical waveguide display structure according to claim 1, characterized in that: The light splitting surface is parallel to the third reflecting surface.
8. The optical waveguide display structure according to claim 1, characterized in that: A plurality of the beam splitting prism units are closely arranged.
9. The optical waveguide display structure according to claim 1, characterized in that: The beam splitting surface is formed by coating a 50%:50% beam splitting film on the inclined surface.
10. The optical waveguide display structure according to claim 1, characterized in that: The light splitting prism unit is in a right-angle trapezoid shape.