CN118091969A

CN118091969A - Speckle suppression component, laser lighting device and display device

Info

Publication number: CN118091969A
Application number: CN202410234021.3A
Authority: CN
Inventors: 兰富洋; 关健; 马国庆; 何强; 王兆民
Original assignee: Meta Bounds Inc
Current assignee: Meta Bounds Inc
Priority date: 2024-02-29
Filing date: 2024-02-29
Publication date: 2024-05-28

Abstract

The application discloses a speckle suppression component, a laser lighting device and display equipment, wherein the speckle suppression component comprises an optical waveguide, a coupling lens and an optical fiber, wherein the optical waveguide, the coupling lens and the optical fiber are arranged along an optical path, the optical waveguide comprises a coupling-in area and a coupling-out area, and the coupling-in area is used for receiving incident light and coupling the incident light into the optical waveguide so as to enable the light to propagate in the optical waveguide; the coupling-out area is provided with a first diffraction microstructure, and the first diffraction microstructure is used for expanding pupils of light rays to form a plurality of light rays with the same propagation direction and different polarization directions, and coupling the plurality of light rays to the coupling lens; the coupling lens is used for coupling out light rays to the input end of the optical fiber so as to combine a plurality of light rays with the same propagation direction and different polarization directions and output the light rays from the output end of the optical fiber. The finally output light has multiple polarization directions so as to reduce the coherence of laser and eliminate laser speckles in an image formed by the laser illuminating device.

Description

Speckle suppression component, laser lighting device and display device

Technical Field

The application relates to the technical field of optics, in particular to a speckle suppression assembly, a laser lighting device and display equipment.

Background

Laser light sources are increasingly used in Display projectors, such as PGUs (Picture Generation Unit, image generating units) for example, in HUDs (Head Up displays) because of their high brightness, wide color gamut, high contrast, etc. However, the laser naturally has high coherence, and when the laser light source is used for projection imaging, the image on the screen has strong granular feel in the view of human eyes, namely, the image has laser speckles, so that the quality of the displayed image is reduced, and the watching effect is influenced.

In order to alleviate the speckle effect generated during the projection of the laser light source, the prior art generally adopts a mode of shaking the device, so that the laser speckle generated at different positions on the surface of the device in a period of time is superimposed and averaged on the retina of a human eye, thereby realizing the purpose of eliminating the sense of image particles. Such as by dithering the projection screen or vibrating the diffuser. Although the laser speckle can be relieved to a certain extent by the methods, the whole system is noisy and worn due to the introduction of the moving device, so that the reliability and the service life of the product are reduced to a certain extent.

Disclosure of Invention

In view of the above, the present application provides a speckle suppression assembly, a laser lighting device and a display device, which can reduce the coherence of laser light, thereby eliminating laser speckle in an image formed by the laser lighting device.

The first aspect of the present application proposes a speckle suppression assembly, comprising an optical waveguide, a coupling lens and an optical fiber arranged along an optical path, the optical waveguide comprising a coupling-in region and a coupling-out region, the coupling-in region being configured to receive an incident light ray and to couple the incident light ray into the optical waveguide, so that the light ray propagates in the optical waveguide;

The coupling-out area is provided with a first diffraction microstructure, and the first diffraction microstructure is used for expanding pupils of the light rays to form a plurality of light rays with the same propagation direction and different polarization directions, and coupling the plurality of light rays to the coupling lens;

The coupling lens is used for coupling out the light rays to the input end of the optical fiber so as to combine the light rays with the same propagation direction and different polarization directions and output the light rays from the output end of the optical fiber.

In some embodiments, the first diffractive microstructure is a one-dimensional grating, a two-dimensional grating, or a super-surface device.

In some embodiments, the coupling-in region is disposed at one side of the coupling-out region in a first direction, the coupling lens and the coupling-out region are disposed opposite to each other in a second direction, the input end of the optical fiber and one side of the coupling lens facing away from the coupling-out region are disposed opposite to each other, the output end of the optical fiber extends in the second direction, and the first direction is perpendicular to the second direction.

In some embodiments, the optical waveguide is further provided with a first reflecting surface, and the first reflecting surface is disposed on a side of the coupling-out area away from the coupling lens, and is configured to reflect the diffracted light generated by the first diffractive microstructure and transmitted away from the coupling lens, so that the reflected diffracted light can be incident on the coupling lens and coupled into the optical fiber through the coupling lens.

In some embodiments, the optical waveguide is further provided with a second reflecting surface, where the second reflecting surface is obliquely disposed at an edge of the coupling-out region and is configured to reflect the light that is not coupled by the first diffractive microstructure to the coupling lens, and a propagation direction of the light reflected by the second reflecting surface is the same as a propagation direction of the light coupled by the first diffractive microstructure.

In some embodiments, the out-coupling region has a first side facing the in-coupling region, a second side opposite the first side, and third and fourth sides connected to the first and second sides and disposed opposite; wherein the optical waveguide is provided with the second reflecting surface on the second side, the third side and the fourth side.

In some embodiments, the second reflective surface is disposed obliquely with respect to the first reflective surface.

In some embodiments, the coupling-in region is provided with a smooth slope for reflecting the incident light, the smooth slope being configured to reflect the incident light such that the reflected light propagates through the optical waveguide by total reflection.

In some embodiments, the coupling-in region is provided with a second diffractive microstructure for diffracting the incident light such that diffracted light enters the optical waveguide for total reflection propagation.

In some embodiments, the second diffractive microstructure is transmissive or reflective; and/or the second diffraction microstructure is a one-dimensional grating, a two-dimensional grating or a super-surface device.

In some embodiments, the speckle reduction assembly further comprises a collimating mirror disposed opposite the output end of the optical fiber, the collimating mirror configured to receive the light coupled out of the optical fiber and collimate the output.

In some embodiments, the speckle reduction assembly further comprises a phase modulator disposed between the out-coupling region and the coupling lens.

The second aspect of the application provides a laser lighting device, which comprises a laser source and a speckle suppression assembly, wherein the laser source is used for emitting laser; the speckle suppression component is used for receiving laser emitted by the laser source and outputting light rays.

A third aspect of the present application proposes a display apparatus, including a display device and a laser lighting device, where the display device is configured to receive light output by the laser lighting device, so as to display an image.

According to the speckle suppression component provided by the application, the first diffraction microstructure is arranged in the coupling-out area of the optical waveguide, so that the incident laser is subjected to pupil expansion to form a plurality of light rays with the same propagation direction but different polarization directions, and then the exit pupil light beams with different polarization directions are combined again through the coupling lens and the optical fiber, so that the finally output light rays have a plurality of polarization directions, the coherence of the laser is reduced, and the laser speckle in an image formed by the laser illumination device is eliminated.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present application, and other drawings may be obtained by those skilled in the art without the inventive effort.

Fig. 1 is a schematic structural diagram of a first embodiment of a speckle reduction assembly according to an embodiment of the present application.

Fig. 2 is a schematic structural diagram of a second embodiment of a speckle reduction assembly according to an embodiment of the present application.

Fig. 3 is a top view of a first embodiment of an optical waveguide according to an embodiment of the present application, and the optical waveguide viewing angles shown in fig. 1 and 2 are cross-sectional viewing angles A-A in fig. 3.

Fig. 4 is a schematic structural diagram of a third embodiment of a speckle reduction assembly according to an embodiment of the present application.

Fig. 5 is a schematic structural diagram of a fourth embodiment of a speckle reduction assembly according to an embodiment of the present application.

Fig. 6 is a top view of a second embodiment of an optical waveguide according to an embodiment of the present application, and the view angle of the optical waveguide shown in fig. 4 and 5 is a cross-sectional view angle at B-B in fig. 6.

Fig. 7 is a schematic diagram of two-dimensional pupil expansion of light by using an optical waveguide according to an embodiment of the present application.

Fig. 8 is a schematic view of the polarization direction of incident light of the incident light entering the optical waveguide shown in fig. 7.

Fig. 9 is a schematic view showing the polarization directions of outgoing light of the light beams having the same propagation directions and different polarization directions, which are emitted after two-dimensional pupil expansion by the optical waveguide shown in fig. 7.

Fig. 10 is a top view of a third embodiment of an optical waveguide according to an embodiment of the present application.

FIG. 11 is a schematic view of a partial structure of the coupling-in region of FIG. 1 with a smooth slope.

Fig. 12 is a schematic view showing a partial structure of the coupling-in region shown in fig. 2 provided with a smooth slope.

Fig. 13 is a K vector diagram of an optical waveguide when the first diffraction microstructure and the second diffraction microstructure according to an embodiment of the present application are two-dimensional gratings.

Fig. 14 is a K vector diagram of an optical waveguide when the first diffraction microstructure and the second diffraction microstructure are one-dimensional gratings according to an embodiment of the present application.

Fig. 15 is a top view of an optical waveguide according to an embodiment of the present application.

Fig. 16 is a perspective view of a back view of a coupling-out region of an optical waveguide according to an embodiment of the present application.

Detailed Description

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

It should be understood that all directional indications (such as up, down, left, right, front, back … …) in embodiments of the present application are merely used to explain the relative positional relationship, movement, etc. between the components in a particular gesture, and that if the particular gesture changes, the directional indication changes accordingly.

It will also be understood that when an element is referred to as being "mounted" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or be indirectly connected to the other element through intervening elements.

The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The description as referred to herein as "first," "second," etc. is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature.

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

Referring to fig. 1-3, an embodiment of the present application provides a speckle suppression assembly 100, which includes an optical waveguide 10, a coupling lens 20 and an optical fiber 30 disposed along an optical path, wherein the optical waveguide 10 includes a coupling-in region 11 and a coupling-out region 12, and the coupling-in region 11 is configured to receive incident light and couple the incident light into the optical waveguide 10 so that the light propagates in the optical waveguide 10; the coupling-out region 12 is provided with a first diffraction microstructure 13, and the first diffraction microstructure 13 is used for expanding pupil of light to form a plurality of light beams with the same propagation direction and different polarization directions, and coupling out the plurality of light beams to the coupling lens 20; the coupling lens 20 is used for coupling light out to the input end of the optical fiber 30 so as to combine a plurality of light beams with the same propagation direction and different polarization directions, and output the light beams from the output end of the optical fiber 30.

The speckle suppression assembly 100 of the embodiment of the application can be used for a laser lighting device, and the first diffraction microstructure 13 is arranged in the coupling-out area 12 of the optical waveguide 10, so that incident laser is subjected to pupil expansion to form a plurality of light beams with the same propagation direction but different polarization directions, and then the exit pupil light beams with different polarization directions are recombined with the optical fiber 30 through the coupling lens 20, so that the finally output light beams have a plurality of polarization directions, the coherence of the laser is reduced, and the laser speckle in an image formed by the laser lighting device is eliminated.

In some embodiments, the first diffractive microstructure 13 may be a one-dimensional grating or a two-dimensional grating or a super-surface device. When the first diffraction microstructure 13 is a one-dimensional grating, the light may be one-dimensional pupil expanded, and when the first diffraction microstructure 13 is a two-dimensional grating, the light may be two-dimensional pupil expanded.

Illustratively, the one-dimensional grating or the two-dimensional grating may be a surface relief grating or a holographic grating. The surface relief grating can be a straight groove grating, an inclined grating, a helical tooth grating, a blazed grating or the like; the holographic grating may be a volume holographic grating or the like.

Illustratively, the elements of the super-surface device may have different shapes and sizes, and a more flexible and versatile diffraction effect may be achieved by precisely controlling the geometry and arrangement of the elements.

Illustratively, when the first diffractive microstructure 13 is a two-dimensional grating, the principle of two-dimensional pupil expansion of light to reduce coherence using an optical waveguide is as follows:

As shown in fig. 1 and fig. 7-fig. 9, the laser enters the optical waveguide 10 from the coupling-in region 11 for total reflection propagation, and after the light reaches the coupling-out region 12, the first micro-diffraction structure 13 in the coupling-out region 12 diffracts the incident light in three different directions, which are the total reflection direction R1, the total reflection direction R2 and the coupling-out direction R3, respectively. The light is a two-dimensional array at the coupling-out position of the coupling-out region 12, so that the expansion of the incident light of the original light beam into two-dimensionally distributed light beams is realized, i.e. the two-dimensional pupil expansion is realized. The total reflection order and the diffraction order are different due to the propagation paths experienced by different outgoing lights, and thus have different polarization directions. That is, after the incident light (as shown in fig. 8) having a single polarization direction is transmitted through the optical waveguide 10, a plurality of light beams having the same propagation direction but different polarization directions are emitted (as shown in fig. 9). In this way, the light rays with different polarization directions are coupled and collimated to become a light ray with poor coherence, so that laser speckles in an image formed by the laser illuminating device are eliminated.

In some embodiments, the optical waveguide 10 may be made of glass or plastic, and the optical waveguide 10 is applied to a laser lighting device, and by matching the first diffraction microstructure 13, the coupling lens 20 and the optical fiber 30, a relatively simple structure is utilized, no moving device is required to be introduced, reliability and service life of a product are greatly improved, coherence of laser is reduced from a root, a necessary condition for generating laser speckles is eliminated, laser speckles in an image are effectively eliminated, and quality of a final display image is improved.

In some embodiments, the coupling lens 20 may be made of glass, quartz, optical glass, or the like. The light is coupled into the optical fiber 30 through the coupling lens 20 to improve the transmission efficiency and reliability of the light.

In some embodiments, as shown in fig. 1-5, the coupling-in region 11 is disposed on one side of the coupling-out region 12 in a first direction, the coupling lens 20 is disposed opposite to the coupling-out region 12 in a second direction, the input end of the optical fiber 30 is disposed opposite to the side of the coupling lens 20 facing away from the coupling-out region 12, the output end of the optical fiber 30 extends in the second direction, and the first direction is perpendicular to the second direction. The speckle reduction assembly 100 of the present application is simple in structure, and the above layout makes the structure compact, reduces the volume, and reduces the cost.

In some embodiments, as shown in fig. 1,2, 4 and 5, the optical waveguide 10 is further provided with a first reflecting surface 14, where the first reflecting surface 14 is disposed on a side of the coupling-out region 12 facing away from the coupling lens 20, and the first reflecting surface 14 is configured to reflect the diffracted light generated by the first diffractive microstructure 13 and transmitted away from the coupling lens 20, so that the reflected diffracted light can be incident on the coupling lens 20 and coupled into the optical fiber 30 through the coupling lens 20. By providing the first reflecting surface 14, light loss can be reduced, and luminous efficiency can be improved.

In some embodiments, as shown in fig. 1-6, 15 and 16, the optical waveguide 10 is further provided with a second reflecting surface 15, where the second reflecting surface 15 is obliquely disposed on an edge of the coupling-out region 12 and is used for reflecting the light that is not coupled out by the first diffractive microstructure 13 to the coupling lens 20, and a propagation direction of the light reflected by the second reflecting surface 15 is the same as a propagation direction of the light coupled out by the first diffractive microstructure 13. By the arrangement of the second reflecting surface 15, light loss can be further reduced, and luminous efficiency can be improved.

In some embodiments, the out-coupling region 12 has a first side 121 facing the in-coupling region 11, a second side 122 opposite the first side 121, and third and fourth sides 123, 124 connected to the first and second sides 121, 122 and disposed opposite each other; the optical waveguide 10 is provided with a second reflecting surface 15 at each of the second side 122, the third side 123 and the fourth side 124. By the cooperation of the three second reflecting surfaces 15 and the first reflecting surface 14 disposed on the second side 122, the third side 123 and the fourth side 124, light loss can be further reduced, and luminous efficiency can be improved.

In some embodiments, as shown in fig. 1, 2,4 and 16, the second reflecting surface 15 is connected to the first reflecting surface 14, and the second reflecting surface 15 is disposed obliquely with respect to the first reflecting surface 14; wherein, the inclination angles of the three second reflecting surfaces 15 and the second reflecting surface 15 may be the same or different.

As shown in fig. 13, the light rays that are not coupled out by the first diffractive microstructure 13 of the coupling-out region 12 are a1, a2, and a2', and therefore, inclined second reflecting surfaces 15 may be disposed on three sides of the coupling-out region 12 for three light rays, respectively, such that the angles of the light rays a1, a2, and a2' become a0 after being reflected by the respective second reflecting surfaces 15, and the inclination angles of the respective second reflecting surfaces 15 may be determined according to a simple geometrical optical reflection principle.

As shown in fig. 15 and 16, the second reflecting surfaces 15 corresponding to a1, a2 and a2' are respectively a reflecting surface 151, a reflecting surface 152 and a reflecting surface 153, and the first reflecting surface 14 is a reflecting surface disposed on the surface of the optical waveguide 10 of the coupling-out region 12 away from the coupling lens 20, and is used for reflecting the diffracted light, which is generated by the first diffractive microstructure 13 of the coupling-out region 10 and transmitted away from the coupling lens 20, so that the light can be incident on the coupling lens 20 and coupled into the optical fiber 30.

In some embodiments, as shown in fig. 1 and 2, the coupling-in region 11 is provided with a smooth bevel 16 for reflecting incident light, the smooth bevel 16 being configured to reflect the incident light such that the reflected light is capable of total reflection propagation within the optical waveguide 10. By providing the smooth inclined surface 16, a certain angle can be formed with the incident light beam, so that the coupling efficiency and stability of the light can be improved, and the reflected light can be totally reflected and propagated in the optical waveguide 10.

As an embodiment, as shown in fig. 1 and 11, the smooth bevel 16 may be inclined in the direction of the coupling-out region 12 towards the direction away from the coupling lens 20, i.e. inclined downwards. The optical waveguide 10 has upper and lower surfaces 10a, an incident angle of light transmitted in the optical waveguide 10 is θ1, an angle between the smooth inclined surface 16 and the surface 10a of the optical waveguide 10 is θ2, and an incident angle of light on the smooth inclined surface 16 is θ0. Wherein arcsin (sin θ0/n) +θ1=θ2, n is the waveguide refractive index. When the incident light is incident perpendicularly to the smooth inclined surface 16 of the incoupling region 11, the light can be totally reflected and propagated in the optical waveguide 10 by the arrangement.

As is clear from the snell's theorem, when the incident angle θ1 of the light transmitted in the optical waveguide 10 is equal to or greater than arcsin (1/n), the light is totally reflected on the upper and lower surfaces 10a of the optical waveguide 10 and cannot enter the air. In the embodiment shown in fig. 11, the incident light is incident perpendicular to the smooth inclined surface 16, and the incident angle is defined as the angle between the light and the normal line of the interface, that is, θ0 is 0 °, so that the reflected light energy loss caused by the smooth inclined surface 16 is minimal, where θ1+.arcsin (1/n), and the angle between the smooth inclined surface 16 and the surface of the optical waveguide 10 is θ2, θ2=θ1. If the incident light is obliquely incident on the surface of the optical waveguide 10, a large amount of reflected light energy is lost.

As an alternative embodiment, as shown in fig. 2 and 12, the smooth bevel 16 may also be inclined in the direction of the coupling-out region 12 towards the coupling lens 20, i.e. obliquely upwards. The optical waveguide 10 has upper and lower surfaces 10a, the incident angle of the light on the smooth inclined surface 16 is θ0, the incident angle of the light on the surface 10a of the optical waveguide 10 is θ1, and the angle between the smooth inclined surface 16 and the surface 10a of the optical waveguide 10 is θ2. When the incident light is incident perpendicular to the lower surface 10a of the optical waveguide 10, the light is reflected by the smooth inclined surface 16, and the reflected light transmission angle enables the light to be totally reflected and propagated in the optical waveguide 10.

As can be seen from the Snell's theorem, when the incident angles θ0 and θ1 of the light transmitted in the optical waveguide 10 are equal to or greater than arcsin (1/n), the light will be totally reflected on the upper and lower surfaces 10a of the optical waveguide 10 and the smooth inclined surface 16, and cannot enter the air, wherein n is the refractive index of the waveguide. In the embodiment shown in fig. 12, the incident light is incident perpendicular to the lower surface 10a of the optical waveguide 10, so that the energy loss of the reflected light caused by the surface 10a of the optical waveguide 10 is minimized, and the included angle between the smooth inclined surface 16 and the surface 10a of the optical waveguide 10 is θ2, θ2=θ0. If the incident light is obliquely incident on the smooth inclined surface 16, more reflected light energy is lost.

In particular applications, the smooth bevel 16 may be coated with a reflective film, such as silver plating, aluminum plating, or the like, to reflect light.

In some embodiments, as shown in fig. 13, the first diffractive microstructure 13 of the coupling-out region 12 is a K-vector diagram of the optical waveguide 10 when it is a two-dimensional grating, where the coupling-in region 11 of the optical waveguide 10 is illustrated by way of example in fig. 12, where a0 represents an incident light ray perpendicular to the surface of the optical waveguide 10, a1 is a light ray totally reflected in the optical waveguide 10 at an incident angle θ1, and a2' are light rays propagating in two different directions totally reflected in the optical waveguide 10 after a1 has been diffracted by the two-dimensional grating of the coupling-out region 12. In fig. 13, two vectors K1 and K2 are two grating vectors of the two-dimensional grating, the direction of the grating vector is the same as the direction of two periods of the two-dimensional grating, k1=λ/d1, k2=λ/d2, d1 and d2 are two periods of the two-dimensional grating, and λ is the wavelength of incident light.

In other embodiments, as shown in fig. 14, when the first diffraction microstructure 13 of the coupling-out region 12 is a one-dimensional grating, the K vector diagram of the optical waveguide 10, K1 is a grating vector of the coupling-out grating (the first diffraction microstructure 13), and when the first diffraction microstructure 13 of the coupling-out region 12 is a one-dimensional grating, only one-dimensional pupil expansion can be achieved.

It should be noted that the coupling-in region 11 is not limited to the configuration of the smooth inclined surface 16, so that the reflected light can be totally reflected and propagated in the optical waveguide 10. For example, in other embodiments, as shown in fig. 4-6, the coupling-in region 11 is provided with a second diffractive microstructure 17, the second diffractive microstructure 17 being configured to diffract incident light such that the diffracted light enters the optical waveguide 10 for total reflection propagation.

As an embodiment, the second diffractive microstructure 17 may be transmissive, as shown in fig. 4.

As another embodiment, as shown in fig. 5, the second diffractive microstructure 17 may also be reflective.

In some embodiments, the second diffractive microstructure 17 is a one-dimensional grating, a two-dimensional grating, or a super-surface device.

As shown in fig. 13, when the second diffraction microstructure 17 is a two-dimensional grating, K3 is a grating vector of the coupling-in grating (second diffraction microstructure 17), the grating vector is consistent with the period direction of the coupling-in grating, and in fig. 13, the length of the grating vector is k3=λ/d3, where d3 is the period of the coupling-in grating, and λ is the wavelength of incident light. Where a0 represents an incident light ray perpendicular to the surface of the optical waveguide 10, a1 is a light ray totally reflected in the optical waveguide 10 at an incident angle θ1, a2 and a2' are light rays totally reflected in two different directions in the optical waveguide 10 after a1 is diffracted by the two-dimensional grating of the coupling-out region 12, and K1 and K2 are respectively coupled out of two grating vectors of the grating (the first diffraction microstructure 13). K1=λ/d1, k2=λ/d2, and d1 and d2 are two periods of the coupling-out grating, respectively.

Fig. 14 shows a case where the second diffractive microstructure 17 is a one-dimensional grating. K1 is the grating vector of the coupling-out grating (first diffraction microstructure 13) and K3 is the grating vector of the coupling-in grating (second diffraction microstructure 17).

In some embodiments, as shown in fig. 1,2,4 and 5, the speckle suppression assembly 100 further includes a collimating lens 40, where the collimating lens 40 is disposed opposite to the output end of the optical fiber 30, and the collimating lens 40 is configured to receive the light coupled out by the optical fiber 30 and collimate the light to make its propagation direction coincide with the axis direction by the collimating lens 40. Of course, the light 30 may be directly connected to other interfaces to output light instead of the collimator 40.

In some embodiments, in order to provide more pronounced polarization differences for the outgoing light, further attenuating the coherence of the light, a phase modulator 50 may also be provided between the coupling-out region 12 of the optical waveguide 10 and the coupling lens 20.

As shown in fig. 10, the speckle reduction assembly 100 further comprises a phase modulator 50, the phase modulator 50 being disposed between the out-coupling region 12 and the coupling lens 20. Illustratively, the phase modulators 50 may be arranged in a two-dimensional array, and the two-dimensional phase modulator array elements may be wave plates, liquid crystals, or other devices having a birefringent effect. Each phase modulation unit covers a beam of emergent light, each phase modulation unit has different phase modulation amounts (realized by changing the thickness or the rotation direction of the device), and different modulation effects can be applied to the emergent light at different positions, so that the coupled light beams are endowed with more random polarization directions.

In addition, the phase modulator unit can be a device capable of being modulated by voltage, for example, when the phase modulator unit contains liquid crystal, the phase modulator unit can change the polarization direction of light in real time along with the change of the applied voltage so as to realize the time averaging of speckles and better eliminate the speckle effect.

The embodiment of the application also provides a laser lighting device, which comprises a laser source and the speckle suppression assembly 100, wherein the laser source is used for emitting laser, and the speckle suppression assembly 100 is used for receiving the laser emitted by the laser source and outputting light. The structure and function of the speckle suppressing assembly 100 in the laser lighting device according to the embodiment of the present application are the same as those of the above embodiment, and specific reference may be made to the description of the above embodiment, which is not repeated.

In some embodiments, the laser lighting device further comprises a structural support for supporting the laser source, the optical waveguide 10, the coupling lens 20, the optical fiber 30 and the collimator lens 40, and a housing for accommodating the above components.

The embodiment of the application also provides a display device which comprises a display device and the laser illuminating device, wherein the display device is used for receiving the light rays output by the laser illuminating device so as to display images. The structure and function of the laser lighting device in the display device according to the embodiment of the present application are the same as those of the foregoing embodiment, and specific reference may be made to the description of the foregoing embodiment, which is not repeated.

Those skilled in the art may combine and combine the features of the different embodiments or examples described in this specification and of the different embodiments or examples without contradiction.

While the application has been described with reference to certain preferred embodiments, it will be understood by those skilled in the art that various changes and substitutions of equivalents may be made and equivalents will be apparent to those skilled in the art without departing from the scope of the application. Therefore, the protection scope of the application is subject to the protection scope of the claims.

Claims

1. A speckle reduction assembly comprising an optical waveguide disposed along an optical path, a coupling lens, and an optical fiber, the optical waveguide comprising an in-coupling region and an out-coupling region, the in-coupling region for receiving incident light and coupling into the optical waveguide such that the light propagates within the optical waveguide;

2. The speckle reduction assembly of claim 1, wherein the first diffractive microstructure is a one-dimensional grating, a two-dimensional grating, or a super-surface device.

3. The speckle reduction assembly of claim 1, wherein the in-coupling region is disposed on a side of the out-coupling region in a first direction, the coupling lens is disposed opposite the out-coupling region in a second direction, the input end of the optical fiber is disposed opposite the side of the coupling lens facing away from the out-coupling region, the output end of the optical fiber extends in the second direction, and the first direction is disposed perpendicular to the second direction.

4. The speckle reduction assembly of claim 1, wherein the optical waveguide is further provided with a first reflective surface disposed on a side of the coupling-out region facing away from the coupling lens, the first reflective surface being configured to reflect diffracted light generated by the first diffractive microstructure that is transmitted away from the coupling lens such that the reflected diffracted light can be incident on the coupling lens and coupled into the optical fiber through the coupling lens.

5. The speckle reduction assembly of claim 4 wherein the optical waveguide is further provided with a second reflective surface that is disposed obliquely to the edge of the out-coupling region and is configured to reflect light that is not coupled by the first diffractive microstructure to the coupling lens, and wherein the direction of light reflected by the second reflective surface is the same as the direction of light coupled by the first diffractive microstructure.

6. The speckle reduction assembly of claim 5, wherein the out-coupling region has a first side facing the in-coupling region, a second side opposite the first side, and third and fourth sides connected to the first and second sides and disposed opposite;

wherein the optical waveguide is provided with the second reflecting surface on the second side, the third side and the fourth side.

7. The speckle reduction assembly of claim 5, wherein the second reflective surface is disposed obliquely with respect to the first reflective surface.

8. The speckle reduction assembly of claim 1, wherein the incoupling region is provided with a smooth bevel for reflecting the incident light, the smooth bevel being configured to reflect the incident light such that the reflected light propagates through the optical waveguide with total reflection.

9. The speckle reduction assembly of claim 1 wherein the incoupling region is provided with a second diffractive microstructure for diffracting the incident light such that diffracted light enters the optical waveguide for total reflection propagation.

10. The speckle reduction assembly of claim 9, wherein the second diffractive microstructure is transmissive or reflective; and/or the second diffraction microstructure is a one-dimensional grating, a two-dimensional grating or a super-surface device.

11. The speckle reduction assembly of claim 1, further comprising a collimating mirror disposed opposite the output end of the optical fiber, the collimating mirror configured to receive the light coupled out of the optical fiber and collimate the output.

12. The speckle reduction assembly of claim 1, further comprising a phase modulator disposed between the out-coupling region and the coupling lens.

13. A laser lighting device, comprising:

a laser source for emitting laser light;

The speckle reduction assembly of any one of claims 1-12, the speckle reduction assembly configured to receive laser light from the laser source and output light.

14. A display device, characterized by comprising:

A display device;

The laser lighting device of claim 13, wherein the display device is configured to receive light outputted from the laser lighting device for displaying an image.