CN219799825U - Light guide system, light source device and display device - Google Patents

Abstract

The utility model relates to a light guide system, a light source device and display equipment. The surface of the optical waveguide is provided with a coupling-in area and a coupling-out area, the optical waveguide is provided with a first surface and a second surface which are opposite, the coupling-in area is arranged on the first surface, and the coupling-in area and the coupling-out area are arranged at intervals in the light propagation direction defined by the optical waveguide. The first coupling-in device is arranged in the coupling-in area and is used for being opposite to the light source, and the first coupling-in device is sensitive to light of a first polarization state. The quarter wave plate is arranged opposite to the second surface at intervals, and the quarter wave plate is positioned on the light path of the light with the second polarization state penetrating the optical waveguide. The reflecting mirror is arranged on one side of the quarter wave plate, which is far away from the optical waveguide, and the second polarized light reflected by the reflecting mirror is converted into the first polarized light after passing through the quarter wave plate again and enters the optical waveguide to propagate along the light propagation direction. The light guide system provided by the utility model can improve the coupling-in efficiency.

Description

Light guide system, light source device and display device

Technical Field

The present utility model relates to the field of light emitting display technologies, and in particular, to a light guide system, a light source device, and a display device.

Background

Augmented reality is a display technology that collects real world information in real time and combines virtual information, images, etc. with the real world. Micro-optical machines used in augmented reality devices are devices for generating image light, and micro-projection systems of LCoS (liquid crystal on silicon) and DMD (digital micromirror device) are the mainstream in non-active light emitting chip projection schemes. For the non-active light emitting chip, the light beam emitted by the light source can be uniformly irradiated on the surfaces of the LCoS and the DMD chip by utilizing the illumination waveguide according to a preset path, so that a high-quality projection image is generated.

When LCoS is used as an image modulator, the polarization state of the illumination beam must be a single polarization state, and when the incident light source is unpolarized, a polarizer is typically used to convert the incident light into a single polarization state. However, the polarization efficiency of the solution is generally lower than 50%, which causes serious loss of energy of the light source, so that the energy consumption of the whole light machine is increased, the cruising is affected, and the heating value of the light machine is increased.

Disclosure of Invention

The embodiment of the utility model provides a light guide system, a light source device and display equipment.

In a first aspect, an embodiment of the present utility model provides a light guiding system, configured to guide light emitted by a light source to a target location, where the light includes first polarized light and second polarized light having different polarization states, and the light guiding system includes an optical waveguide, a first coupling-in device, a quarter wave plate, and a reflecting mirror. The surface of the optical waveguide is provided with a coupling-in area and a coupling-out area, the optical waveguide is provided with a first surface and a second surface which are opposite, the coupling-in area is arranged on the first surface, and the coupling-in area and the coupling-out area are arranged at intervals in the light propagation direction defined by the optical waveguide. The first coupling-in device is arranged in the coupling-in area and is used for being opposite to the light source, the first coupling-in device is sensitive to light with a first polarization state, so that after light is coupled into the optical waveguide through the first coupling-in device, the light with the first polarization state can propagate along the light propagation direction, and the light with the second polarization state penetrates the optical waveguide. The quarter wave plate is arranged opposite to the second surface at intervals, and the quarter wave plate is positioned on the light path of the light with the second polarization state penetrating the optical waveguide. The reflecting mirror is arranged on one side of the quarter wave plate, which is away from the optical waveguide, and is used for reflecting the second polarized light penetrating through the quarter wave plate, and the second polarized light reflected by the reflecting mirror is converted into the first polarized light after passing through the quarter wave plate again and enters the optical waveguide to propagate along the light propagation direction.

In some alternative embodiments, the first incoupling means has a diffraction efficiency of greater than or equal to 50% for light of the first polarization state.

In some alternative embodiments, the first incoupling means has a diffraction efficiency of less than or equal to 5% for light of the second polarization state.

In some alternative embodiments, the coupling-out region is provided with first coupling-out means comprising at least one of the following structures: surface relief gratings, bragg gratings, holographic volume gratings, supersurfaces, photonic crystals, diffractive optical elements.

In some alternative embodiments, the light guiding system further includes a second coupling-in device disposed on the second surface, the second coupling-in device being located on the optical path of the light reflected by the mirror to the optical waveguide, the light of the first polarization being incident on the second coupling-in device for diffraction; the light of the second polarization state reflected by the reflecting mirror is converted into light of the first polarization state through the quarter wave plate and is coupled into the optical waveguide through the second coupling-in device.

In some alternative embodiments, the light guiding system further includes a second coupling-out device disposed on the second surface or/and the first surface and located between the coupling-in region and the coupling-out region, and the light with the second polarization state in the optical waveguide is coupled out through the second coupling-out device.

In some alternative embodiments, the second coupling-out means comprises at least one of the following structures: gratings, supersurfaces, photonic crystals, diffractive optical elements.

In some alternative embodiments, the first coupling-in means comprises at least one of the following structures: gratings, supersurfaces, photonic crystals, diffractive optical elements.

In a second aspect, an embodiment of the present utility model further provides a light source device, including a light source and a light guiding system according to any one of the foregoing embodiments, where the light source is disposed on a side of the optical waveguide where the coupling-in area is disposed, and the light source is opposite to the first coupling-in device.

In some alternative embodiments, the light source comprises an unpolarized light source, the first polarization state light being s-polarized light, the second polarization state light being p-polarized light; or the light source comprises an unpolarized light source, the first polarization state light being p-polarized light and the second polarization state light being s-polarized light.

In a third aspect, an embodiment of the present utility model further provides a display device, including any one of the light source devices, a display, and a projection lens, where the display is disposed on a side of the optical waveguide where the coupling-out area is disposed and opposite to the coupling-out area; the projection lens is arranged on one side of the optical waveguide, which is away from the display.

In some alternative embodiments, the display device further comprises an analyzer disposed between the projection lens and the optical waveguide; the display includes a bright pixel for modulating light of a first polarization state into light of a second polarization state and reflecting the light, and a dark pixel for reflecting light of the first polarization state, and an analyzer for blocking the light of the first polarization state from propagating to the projection lens.

Compared with the prior art, the light guide system provided by the embodiment of the utility model is applied to the light source device, when the light guide system works, the light source emits light beams, the light beams are incident to the first coupling-in device, first polarized light in the incident light is diffracted and enters the optical waveguide to propagate along the light propagation direction, second polarized light penetrates the optical waveguide and is reflected by the reflecting mirror to be coupled into the optical waveguide again, and in the process, the quarter wave plate converts the second polarized light into the first polarized light. And the characteristic of the first coupling-in device on the first polarized light sensitivity is utilized to transmit the second polarized light out of the optical waveguide, the second polarized light is converted into the first polarized light under the action of the quarter wave plate and the reflecting mirror and then is coupled into the optical waveguide again, and the coupling-in efficiency is improved, so that the energy transmission efficiency of the whole light guide system is improved.

Drawings

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

Fig. 1 is a simplified schematic structure of a display device according to an embodiment of the present utility model.

Fig. 2 is a simplified schematic diagram of a light guiding system according to an embodiment of the present utility model.

Fig. 3 is a schematic view of the structure of an optical waveguide of the light guiding system shown in fig. 2.

Fig. 4 is a schematic structural diagram of another embodiment of the light guide system shown in fig. 2.

Fig. 5 is a schematic structural view of a further embodiment of the light guide system shown in fig. 2.

Marking: 100. a light guide system; 10. an optical waveguide; 12. a coupling-in region; 14. a coupling-out region; 16. a first surface; 17. a sidewall; 18. a second surface; 20. a first coupling-in device; 30. a first coupling-out device; 40. a quarter wave plate; 50. a reflecting mirror; 60. a second coupling-in device; 70. a second coupling-out device; 200. a light source device; 201. a light source; 300. a display device; 301. a display; 3012. a bright pixel; 3014. dark pixels; 302. a projection lens; 303. and an analyzer.

Detailed Description

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

In the description of the present utility model, it should be understood that the terms "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present utility model and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present utility model.

In the description of the present utility model, it should be noted that, unless explicitly stated and limited otherwise, the terms "mounted", "connected" and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected. Either mechanically or electrically. Can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

Referring to fig. 1, an embodiment of the present utility model provides a light source apparatus 200, where the light source apparatus 200 is applied to a display device 300, and is used for generating a projection display image.

The specific type of the display device 300 is not limited in this specification, and the display device 300 may be applied to, for example, a head-up display (HMD), a head-up display (HUD), and other wearable glasses devices, etc., of course, the display device 300 may be a projector. In the present embodiment, the display apparatus 300 includes the light source device 200, the display 301, and the projection lens 302. The light source device 200 includes a light source 201 and a light guiding system 100, wherein the light source 201 is used for emitting a light beam, and the light guiding system 100 is disposed at one side of the light source 201. The optical waveguide of the light guiding system 100 is provided with an in-coupling region 12 and an out-coupling region 14, the in-coupling region 12 being located in the optical path of the light beam emitted by the light source 201. The display 301 is disposed on a side of the optical waveguide having the coupling-out region 14 and is located on an optical path of the light coupled out from the coupling-out region 14. The projection lens 302 is disposed on a side of the optical waveguide of the light guide system 100 facing away from the display 301, and corresponds to a position of the display 301 along a thickness direction of the optical waveguide of the light guide system 100.

In operation, the light source 201 emits a light beam, the light beam enters the light guide of the light guide system 100 through the coupling-in region 12 and propagates in the light guide of the light guide system 100 at a certain angle, and when the light beam is incident on the interface between the light guide of the light guide system 100 and the air, total reflection occurs, which ensures that the light beam can propagate in the light guide of the light guide system 100 along a set path to reach the coupling-out region 14, finally leaves the light guide of the light guide system 100 through the coupling-out region 14 to enter the display 301, the display 301 modulates the light beam and reflects the modulated light beam to the projection lens 302, and finally enters the human eye.

In the description of the present utility model, it should be understood that the terms "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "inner," and the like indicate orientation or positional relationships based on that shown in the drawings, and are merely used for simplifying the description of the present utility model, rather than indicating or implying that the apparatus or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present utility model.

The specific type of the light source 201 is not limited in this specification, for example, the light source 201 may be a linear polarization laser, or an unpolarized light source such as an LED (light emitting diode) or a combination of other lasers and polarizers, so that the light beam emitted therefrom is collimated and homogenized into a uniform spot. In this embodiment, the light source 201 is a non-polarized light source. The present embodiment has no limitation in the wavelength and spectral width of the light emitted from the light source 201.

The display 301 is disposed opposite to the coupling-out region 14, and is configured to modulate the light beam coupled out through the coupling-out region 14 and reflect the modulated light beam to the projection lens 302. The display 301 is used to generate an image source and control brightness of pixels in an image, the display 301 is an optical display device that does not actively emit light, and the specific type of the display 301 is not limited in this specification, and for example, the display 301 may be an LCOS (liquid crystal on silicon) display panel, or an LCD (liquid crystal display). In this embodiment, the display 301 is an LCOS display panel. The display 301 may include a plurality of bright pixels 3012 and a plurality of dark pixels 3014, the plurality of bright pixels 3012 and the plurality of dark pixels 3014 each being arranged in an array interval, and the bright pixels 3012 and the dark pixels 3014 being arranged in a cross interval. Wherein the bright pixels 3012 are used to modulate and reflect light and the dark pixels 3014 are used to directly reflect light.

In this embodiment, projection lens 302 is used to map the image source of display 301 into the human eye for imaging. In order to improve the imaging definition, in the present embodiment, the display apparatus 300 may further include an analyzer 303, where the analyzer 303 is disposed between the projection lens 302 and the light guide system 100 and is disposed opposite to the projection lens 302. The projection lens 302, the analyzer 303, the optical waveguide 10, and the display 301 are arranged in the thickness direction of the optical waveguide 10 in parallel at intervals. The analyzer 303 is a polarizing plate, and mainly functions to convert incident light into linearly polarized light and emit the linearly polarized light. In this embodiment, the analyzer 303 is an absorbing polarizer, which only allows light with a certain polarization state to pass through, and reflects or absorbs light with other polarization states, so as to ensure the definition of the image.

Referring to fig. 1 and fig. 2, the light guide system 100 is configured to constrain a propagation path of a light beam emitted from the light source 201, and guide the light beam emitted from the light source 201 to a target position. The "target position" may be an inactive light emitting chip of the display device, and in this embodiment, the "target position" is a surface of the display 301 near the light guiding system 100. The light includes first polarized light O1 and second polarized light O2 having different polarization states. In this embodiment, the light guiding system 100 may comprise an optical waveguide 10, a first in-coupling device 20, a first out-coupling device 30, a quarter wave plate 40 and a mirror 50. The first coupling-in device 20 is disposed in the coupling-in region 12, the first coupling-out device 30 is disposed in the coupling-out region 14, and the quarter wave plate 40 and the reflecting mirror 50 are disposed on a side of the optical waveguide 10 facing away from the light source 201 and are sequentially arranged in parallel along a direction away from the optical waveguide 10.

The first coupling-in device 20 is sensitive to the first polarized light O1, the light enters the first coupling-in device 20, the first polarized light O1 in the incident light is diffracted and enters the optical waveguide 10 to propagate along the light propagation direction z, the second polarized light O2 penetrates the optical waveguide 10 and is reflected by the reflecting mirror 50, and is coupled into the optical waveguide 10 again, and in this process, the quarter wave plate 40 converts the second polarized light O2 into the first polarized light O1. Therefore, in the present embodiment, the characteristic that the first coupling-in device 20 is sensitive to the first polarized light O1 is utilized to transmit the second polarized light O2 out of the optical waveguide 10, and the second polarized light O2 is converted into the first polarized light O1 under the action of the quarter wave plate 40 and the reflecting mirror 50 and then coupled into the optical waveguide 10 again, so as to improve the coupling-in efficiency, thereby improving the energy transmission efficiency of the whole light guiding system 100.

Referring to fig. 3, in the present embodiment, the optical waveguide 10 is a guiding structure for transmitting optical frequency electromagnetic waves, which is formed by an optically transparent medium (e.g. quartz glass), and is a device for guiding the propagation of the optical wave therein, which is used to limit the propagation path of the optical beam in space, and can only propagate in the optical waveguide 10 when the propagation angle of the optical beam satisfies the total reflection condition. The specific type of the optical waveguide 10 is not limited in the present specification, and the optical waveguide 10 may be made in a very thin plate glass form. In this embodiment, the optical waveguide 10 may be a glass plate 101. The glass plate 101 has a refractive index n, a thickness d, and a critical angle θ for total reflection of the glass plate 101 ₀ ＝arcsin(n _a N), where n _a Is the refractive index of air. The greater the refractive index n of the optical waveguide 10, the greater the total reflection critical angle θ ₀ The smaller the angle range over which total reflection of light can occur within the optical waveguide 10 increases, increasing the degree of freedom of design.

Referring again to fig. 1 and 2, optical waveguide 10 includes a first surface 16, a second surface 18, and sidewalls 17. The first surface 16 and the second surface 18 face away from each other, wherein the first surface 16 is arranged towards the light source 201 and the second surface 18 is arranged towards the projection lens 302, and the side wall 17 is connected between the first surface 16 and the second surface 18. The optical waveguide 10 may be generally planar in shape, and thus the first and second surfaces 16 and 18 may be planar, and in other embodiments, the optical waveguide 10 may be curved in shape, and the first and second surfaces 16 and 18 may be concave and convex, respectively; the optical waveguide 10 may have a circular plate-like shape, and the first surface 16 and the second surface 18 may each have an arcuate surface.

In the present disclosure, the terms "first," "second," and "second" are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implying a number of technical features being indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present utility model, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

The coupling-in region 12 is disposed on the first surface 16, and the coupling-in region 12 and the light source 201 are disposed opposite to each other at a distance. The coupling-out region 14 is disposed on the surface of the optical waveguide 10, and the coupling-out region 14 is disposed opposite to the display 301 with a space therebetween. The specific location of the out-coupling region 14 is not limited in this specification, and for example, the out-coupling region 14 may be disposed on the same side as the in-coupling region 12 and also on the first surface 16. The coupling-out region 14 may also be located on a different side than the coupling-in region 12, for example, the coupling-out region 14 is located on the second surface 18 or on the sidewall 17. For convenience of processing, the coupling-in region 12 and the coupling-out region 14 are disposed on the same side, and in this embodiment, the coupling-in region 12 and the coupling-out region 14 are disposed on the first surface 16, and the coupling-in region 12 and the coupling-out region 14 are disposed at intervals in the light propagation direction z defined by the optical waveguide 10. The specific direction of the light propagation direction z is not limited in this specification, and for example, the light propagation direction z may be the longitudinal direction of the optical waveguide 10 or the width direction of the optical waveguide 10, and in this embodiment, the light propagation direction z is the longitudinal direction of the optical waveguide 10.

In this embodiment, the first coupling-in device 20 is disposed in the coupling-in region 12 and opposite to the light source 201, and the first coupling-in device 20 is sensitive to the first polarized light O1, so that after the light is coupled into the optical waveguide 10 via the first coupling-in device 20, the first polarized light O1 in the light can be diffracted by the first coupling-in device 20 to propagate along the light propagation direction z, part of the second polarized light O2 penetrates the optical waveguide 10 in a direction perpendicular to the first surface 16, and part of the second polarized light O2 enters the optical waveguide 10 in a direction perpendicular to the first surface 16, and is diffracted by the first coupling-in device 20 to propagate along the light propagation direction z. The specific type of the first coupling-in device 20 is not limited in this specification, and for example, the first coupling-in device 20 includes at least one of the following structures: gratings, supersurfaces, photonic crystals, diffractive Optical Elements (DOEs). The grating is a dispersive element for splitting light by utilizing interference and diffraction phenomena of light. The super surface is an artificial layered material with the thickness smaller than the wavelength, and can realize flexible and effective regulation and control of the characteristics of polarization, amplitude, phase, polarization mode, propagation mode and the like of electromagnetic waves. Photonic crystals refer to artificial periodic dielectric structures having photonic band gap characteristics, sometimes also referred to as PBG (photonic band gap) photonic crystal structures. The diffractive optical element is a series of movable mirrors in a lithographic apparatus, which are mainly used to generate the light source required for lithography.

The first incoupling means 20 have a minimum feature size in the range of micrometers to nanometers, which enables a strong diffraction efficiency for a certain polarization state, e.g. a strong diffraction efficiency for light O1 of a first polarization state and a low diffraction efficiency for light O2 of another polarization state, e.g. a second polarization state, as described above. The specific types of the first polarized light O1 and the second polarized light O2 are not limited in this specification, for example, the first polarized light O1 may be s polarized light, and the second polarized light O2 is p polarized light; alternatively, the first polarized light O1 may be p polarized light and the second polarized light O2 s polarized light. In this embodiment, the first polarized light O1 is s polarized light, and the second polarized light O2 is p polarized light. I.e. the first incoupling means 20 has a higher diffraction efficiency for s-polarized light and a lower diffraction efficiency for p-polarized light, i.e. the first incoupling means 20 has a diffraction efficiency for s-polarized light that is much greater than for p-polarized light. The higher the diffraction order efficiency of the first polarized light O1 into the optical waveguide 10, the better, and in this embodiment, the diffraction efficiency of the first coupling-in device 20 on the first polarized light O1 is greater than or equal to 50%. The above-mentioned increase in the diffraction efficiency of p-polarized light, i.e. the second polarized light O2, leads to a decrease in the projection contrast, the higher the diffraction order efficiency of the second polarized light O2 coupled into the optical waveguide 10, the better the diffraction efficiency of the first coupling-in device 20 for the second polarized light O2 is less than or equal to 5%.

Therefore, the first coupling-in device 20 disposed in the coupling-in region 12 changes the propagation angle of the first polarized light O1 in the light beam emitted by the light source 201 through the diffraction effect, so that the angle of the first polarized light O1 satisfies the total reflection condition in the optical waveguide 10, thereby realizing substantially lossless transmission of the first polarized light O1 in the optical waveguide 10 (neglecting the absorption effect of the material of the optical waveguide 10 on the light). The first incoupling means 20 does not substantially change the propagation angle and propagation path of the light O2 of the second polarization state, enabling the light O2 of the second polarization state to penetrate the optical waveguide 10 to the quarter wave plate 40. In this embodiment, the optical waveguide 10 may also serve as a substrate for the first coupling-in device 20, so that the first coupling-in device 20 may be attached thereto.

In this embodiment, the quarter wave plate 40 is disposed opposite to the second surface 18 of the optical waveguide 10, and is located on the optical path where the second polarized light O2 passes through the optical waveguide 10. The projection of the quarter wave plate 40 onto the optical waveguide 10 covers the projection of the first coupling-in device 20 onto the optical waveguide 10. The quarter wave plate 40, also called a "quarter wave plate", is a birefringent single crystal wave plate of a certain thickness. When light is transmitted through the quarter wave plate from normal incidence, the phase difference between ordinary and extraordinary rays is equal to pi/2 or an odd multiple thereof, and such a wafer is called a quarter wave plate or a 1/4 wave plate. The quarter wave plate 40 is commonly used to change linearly polarized light into circularly polarized light or elliptically polarized light or circularly polarized light or elliptically polarized light into linearly polarized light in the optical path.

In this embodiment, the mirror 50 is disposed on a side of the quarter-wave plate 40 facing away from the optical waveguide 10, and is configured to reflect the second polarized light O2 that has penetrated the quarter-wave plate 40. The mirror 50 is an optical element that operates using the law of reflection and has a high reflectance. The specific structure of the reflecting mirror 50 is not limited in this specification, and for example, the reflecting mirror 50 may be an integrated form of a reflection enhancing dielectric film, a metal film, an optical microstructure, or the like plated on the quarter wave plate 40, or may be a separate reflecting device.

In operation, light is incident on the first coupling-in device 20, and light O2 of the second polarization state in the incident light passes through the optical waveguide 10, passes through the quarter-wave plate 40, is reflected by the reflecting mirror 50, and then passes through the quarter-wave plate 40 again to enter the optical waveguide 10. Through the twice quarter wave plate 40, the second polarized light O2 is converted into the first polarized light O1, and the first polarized light O1 enters the optical waveguide 10 and is transmitted to the first coupling-in device 20 to be diffracted, so that the first polarized light propagates along the light propagation direction z, and the coupling-in efficiency is improved.

In the present embodiment, the first coupling-out device 30 is disposed in the coupling-out region 14, which is used to break the total reflection condition, so that the light O1 with the first polarization state is coupled out from the first surface 16 at the same angle and in the opposite direction as the incident light. The specific structure of the first coupling-out device 30 is not limited in this specification, and for example, the first coupling-out device 30 includes at least one of the following structures: surface relief gratings, bragg gratings, holographic volume gratings, supersurfaces, photonic crystals, diffractive optical elements. The first polarized light O1 of the incident light and the first polarized light O1 converted by the second polarized light O2 are coupled out via the first coupling-out device 30 after propagating in the light waveguide 10 along the light propagation direction z to the coupling-out region 14. The coupled light beam uniformly irradiates the display 301, the display 301 modulates the polarization state of the light, the bright pixel 3012 modulates the incident light O1 with the first polarization state into the light O2 with the second polarization state and reflects the light, the dark pixel 3014 directly reflects the light O1 with the first polarization state, the modulated light beam reflects and irradiates the analyzer 303 through the optical waveguide 10, the analyzer 303 can only pass the light O2 with the second polarization state, and only the image corresponding to the bright pixel 3012 enters the projection lens 302 for display.

Referring to fig. 4, if the first coupling-in device 20 has a direction selectivity, that is, the diffraction efficiency of the first polarized light O1 emitted by the light source 201 (as shown in fig. 1) and the diffraction efficiency of the first polarized light O1 reflected by the reflecting mirror 50, entering the optical waveguide 10 and entering the first coupling-in device 20 are different. To increase the diffraction efficiency of the first polarization state light O1 reflected by the mirror 50 into the optical waveguide 10 and incident to the first incoupling device 20, the light guiding system 100 may further comprise a second incoupling device 60 in some embodiments.

The second coupling-in device 60 is disposed on the second surface 18 and is located on the optical path of the light reflected by the reflecting mirror 50 to the optical waveguide 10. Like the first incoupling device 20, the second incoupling device 60 is also sensitive to the first polarized light O1, i.e. the first polarized light O1 is incident on the second incoupling device 60 and diffracted. The second polarized light O2 is converted into the first polarized light O1 by the mirror 50 and the quarter wave plate 40 and coupled into the optical waveguide 10 via the second coupling-in means 60. The second coupling-in device 60 can couple the converted light O1 with the first polarization state into the optical waveguide 10 with higher efficiency, so as to further improve the energy transfer efficiency of the light guiding system 100.

Referring to fig. 5, as described above, the increase of the diffraction efficiency of the second polarized light O2 may result in a decrease of the contrast of the projected image, and in order to improve the purity of the first polarized light O1 in the optical waveguide 10, in some embodiments, the light guiding system 100 may further include a second coupling-out device 70, where the second coupling-out device 70 is disposed on the second surface 18 or/and the first surface 16 and is located between the coupling-in region 12 and the coupling-out region 14. The second outcoupling means 70 is sensitive to the second polarized light O2, i.e. the diffraction efficiency of the second outcoupling means 70 for the second polarized light O2 is larger than the diffraction efficiency for the first polarized light O1, e.g. the diffraction efficiency of the second outcoupling means 70 for the second polarized light O2 is larger than or equal to 50% and the diffraction efficiency of the second outcoupling means 70 for the first polarized light O1 is smaller than or equal to 5%. Thereby, the second polarized light O2 in the optical waveguide 10 is coupled out of the optical waveguide 10 via the second coupling-out device 70, so that the contrast of the projection picture is improved, and the transmission efficiency of the first polarized light O1 in the optical waveguide 10 is not affected. The specific structure of the second coupling-out device 70 is not limited in this specification, and for example, the second coupling-out device 70 may include at least one of the following structures: gratings, supersurfaces, photonic crystals, diffractive Optical Elements (DOEs). The grating is a dispersive element for splitting light by utilizing interference and diffraction phenomena of light. The super surface is an artificial layered material with the thickness smaller than the wavelength, and can realize flexible and effective regulation and control of the characteristics of polarization, amplitude, phase, polarization mode, propagation mode and the like of electromagnetic waves. Photonic crystals refer to artificial periodic dielectric structures having photonic band gap characteristics, sometimes also referred to as PBG (photonic band gap) photonic crystal structures. The diffractive optical element is a series of movable mirrors in a lithographic apparatus, which are mainly used to generate the light source required for lithography.

In the light guiding system 100 provided in the embodiment of the present utility model, the first coupling-in device 20 is sensitive to the first polarized light O1, the light is incident into the first coupling-in device 20, the first polarized light O1 in the incident light is diffracted and enters the optical waveguide 10 to propagate along the light propagation direction z, and the second polarized light O2 in the incident light penetrates the optical waveguide 10 and is reflected by the reflecting mirror 50 after passing through the quarter wave plate 40, and then enters the optical waveguide 10 again through the quarter wave plate 40. Through the twice quarter wave plate 40, the second polarized light O2 is converted into the first polarized light O1, enters the optical waveguide 10 and is transmitted to the first coupling-in device 20 to be diffracted, so that the light propagates along the light propagation direction z, and the coupling-in efficiency is improved. The characteristic that the first coupling-in device 20 is sensitive to the first polarized light O1 is utilized to transmit the second polarized light O2 out of the optical waveguide 10, and under the action of the quarter wave plate 40 and the reflecting mirror 50, the second polarized light O2 is converted into the first polarized light O1 and then is coupled into the optical waveguide 10 again, so that the coupling-in efficiency is improved, and the energy transfer efficiency of the whole light guiding system 100 is improved.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present utility model. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present utility model, and are not limiting; although the utility model has been described in detail with reference to the foregoing embodiments, it will be appreciated by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not drive the essence of the corresponding technical solutions to depart from the spirit and scope of the technical solutions of the embodiments of the present utility model.

Claims (12)

1. A light guide system for directing light from a light source to a target location, the light comprising first and second polarized light of different polarization states, the light guide system comprising:

the optical waveguide comprises an optical waveguide body, wherein the surface of the optical waveguide body is provided with a coupling-in area and a coupling-out area, the optical waveguide body is provided with a first surface and a second surface which are opposite, the coupling-in area is arranged on the first surface, and the coupling-in area and the coupling-out area are arranged at intervals in the light propagation direction defined by the optical waveguide body;

the first coupling-in device is arranged in the coupling-in area and is used for being opposite to the light source, the first coupling-in device is sensitive to the light with the first polarization state, so that after the light is coupled into the optical waveguide through the first coupling-in device, the light with the first polarization state can propagate along the light propagation direction, and the light with the second polarization state penetrates through the optical waveguide;

the quarter wave plate is arranged at an interval opposite to the second surface and is positioned on a light path of the second polarized light penetrating through the optical waveguide; and

the reflecting mirror is arranged on one side of the quarter wave plate, which is away from the optical waveguide, and is used for reflecting the second polarized light penetrating through the quarter wave plate, and the second polarized light reflected by the reflecting mirror passes through the quarter wave plate again and is converted into first polarized light, enters the optical waveguide and propagates along the light propagation direction.

2. The light guide system of claim 1, wherein the first incoupling device has a diffraction efficiency of greater than or equal to 50% for the light of the first polarization state.

3. The light guide system of claim 1, wherein the first incoupling device has a diffraction efficiency of less than or equal to 5% for light of the second polarization state.

4. The light guide system of claim 1, wherein the out-coupling region is provided with a first out-coupling means comprising at least one of the following structures: surface relief gratings, bragg gratings, holographic volume gratings, supersurfaces, photonic crystals, diffractive optical elements.

5. The light guide system of any one of claims 1-4, further comprising a second in-coupling device disposed on the second surface, the second in-coupling device being in an optical path of light reflected by the mirror to the light guide, the first polarization state light being incident on the second in-coupling device for diffraction; the second polarized light reflected by the reflecting mirror is converted into the first polarized light via the quarter wave plate and coupled into the optical waveguide via the second coupling-in device.

6. The light guide system of any of claims 1-4, further comprising a second out-coupling device disposed on the second surface or/and the first surface and between the in-coupling region and the out-coupling region, wherein light of a second polarization within the optical waveguide is coupled out by the second out-coupling device.

7. The light guide system of claim 6, wherein the second out-coupling means comprises at least one of the following structures: gratings, supersurfaces, photonic crystals, diffractive optical elements.

8. The light guiding system according to any of claims 1-4, wherein the first coupling-in means comprises at least one of the following structures: gratings, supersurfaces, photonic crystals, diffractive optical elements.

9. A light source device, comprising:

a light source; and

the light guide system according to any one of claims 1 to 8, wherein the light source is arranged on a side of the light guide where the coupling-in region is arranged, the light source being opposite to the first coupling-in device.

10. A light source device according to claim 9, wherein,

the light source comprises an unpolarized light source, the first polarized light is s polarized light, and the second polarized light is p polarized light; or alternatively

The light source comprises an unpolarized light source, the first polarized light is p-polarized light, and the second polarized light is s-polarized light.

11. A display device, characterized by comprising:

the light source device according to any one of claims 9 to 10;

the display is arranged at one side of the optical waveguide, provided with the coupling-out region, and is opposite to the coupling-out region; and

the projection lens is arranged on one side of the optical waveguide, which is away from the display.

12. The display device of claim 11, further comprising an analyzer disposed between the projection lens and the optical waveguide; the display includes a bright pixel for modulating the first polarization state light into the second polarization state light and reflecting the second polarization state light, and a dark pixel for reflecting the first polarization state light, and an analyzer for blocking the first polarization state light from propagating to the projection lens.