Speckle suppression assembly, laser illumination apparatus, and display device

Abstract

A speckle suppression assembly (100), a laser illumination apparatus and a display device. The speckle suppression assembly (100) comprises an optical waveguide (10), a coupling lens (20) and an optical fiber (30) arranged along an optical path, wherein the optical waveguide (10) comprises a coupling-in region (11) and a coupling-out region (12), the coupling-in region (11) being used for receiving incident light rays and coupling same into the optical waveguide (10) to allow the light rays to propagate within the optical waveguide (10), and the coupling-out region (12) being provided with a first diffractive microstructure (13), the first diffractive microstructure (13) being used for pupil expansion of light rays to form a plurality of light beams having the same propagation direction and different polarization directions, and to couple the plurality of light beams out to the coupling lens (20); and the coupling lens (20) is used for coupling and outputting the light rays to an input end of the optical fiber (30) to combine the plurality of light beams having the same propagation direction and different polarization directions, and output same from an output end of the optical fiber (30). In this way, the resulting output light rays have a plurality of polarization directions to reduce the coherence of a laser, thereby eliminating laser speckling in an image formed by the laser illumination apparatus.

Description

Speckle suppression component, laser lighting device and display equipment

[0001] This application claims priority to Chinese patent application No. 2024102340213, filed with the Patent Office of China on February 29, 2024, entitled “Speckle Suppression Component, Laser Illumination Device and Display Device,” the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present application relates to the field of optical technology, and in particular to a speckle suppression component, a laser lighting device, and a display device. Background Art

[0003] Laser light sources, due to their advantages such as high brightness, wide color gamut, and high contrast, are increasingly being used in display projectors, such as the PGU (Picture Generation Unit) in HUD (Head-Up Display). However, lasers are naturally highly coherent. When projecting images using laser light sources, the image on the screen appears grainy to the human eye. This phenomenon, known as laser speckle, reduces image quality and affects viewing experience.

[0004] To mitigate the speckle effect produced by laser projection, existing technologies typically employ device dithering. This allows the laser speckle generated at different locations on the device surface to be superimposed and averaged on the retina over time, thereby eliminating the graininess of the image. Examples include dithering the projection screen or vibrating the diffuser. While these methods can mitigate laser speckle to a certain extent, the introduction of moving components can lead to noise and wear throughout the system, reducing product reliability and lifespan. Summary of the Invention

[0005] In view of this, the present application proposes a speckle suppression component, a laser lighting device, and a display device to reduce the coherence of the laser, thereby eliminating laser speckles in the image formed by the laser lighting device.

[0006] In a first aspect, the present application provides a speckle reduction assembly, comprising an optical waveguide, a coupling lens, and an optical fiber arranged along an optical path. The optical waveguide comprises an incoupling region and an outcoupling region. The incoupling region is configured to receive incident light and couple it into the optical waveguide, so that the light propagates within the optical waveguide.

[0007] The outcoupling region is provided with a first diffraction microstructure, which is used to expand the pupil of the light to form multiple beams of light with the same propagation direction and different polarization directions, and couple the multiple beams of light to the coupling lens;

[0008] The coupling lens is used to couple the light to the input end of the optical fiber, so as to combine multiple light beams with the same propagation direction but different polarization directions and output them from the output end of the optical fiber.

[0009] In a second aspect, the present application provides a laser lighting device, comprising a laser source and a speckle suppression component, wherein the laser source is configured to emit laser light; and the speckle suppression component is configured to receive the laser light emitted by the laser source and output light.

[0010] A third aspect of the present application provides a display device, comprising a display device and a laser lighting device, wherein the display device is configured to receive light output by the laser lighting device to display an image.

[0011] The speckle reduction component proposed in this application provides a first diffraction microstructure in the outcoupling region of an optical waveguide to perform pupil expansion on the incident laser light, thereby forming multiple beams of light with the same propagation direction but different polarization directions. The outcoupling light beams with different polarization directions are then recombined through a coupling lens and an optical fiber, so that the final output light has multiple polarization directions, thereby reducing the coherence of the laser light and eliminating laser speckle in the image formed by the laser illumination device. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained from these drawings without any creative work.

[0013] FIG1 is a schematic structural diagram of a first embodiment of a speckle reduction assembly according to an embodiment of the present application.

[0014] FIG2 is a schematic structural diagram of a second embodiment of a speckle reduction assembly proposed in an embodiment of the present application.

[0015] FIG3 is a top view of a first embodiment of the optical waveguide proposed in an embodiment of the present application. The viewing angle of the optical waveguide shown in FIG1 and FIG2 is a cross-sectional viewing angle at AA in FIG3 .

[0016] FIG4 is a schematic structural diagram of a third embodiment of a speckle reduction assembly according to an embodiment of the present application.

[0017] FIG5 is a schematic structural diagram of a fourth embodiment of a speckle reduction assembly proposed in an embodiment of the present application.

[0018] FIG6 is a top view of a second embodiment of the optical waveguide proposed in an embodiment of the present application. The perspectives of the optical waveguide shown in FIG4 and FIG5 are cross-sectional perspectives at point BB in FIG6 .

[0019] FIG7 is a schematic diagram showing the principle of implementing two-dimensional pupil expansion of light by the optical waveguide proposed in an embodiment of the present application.

[0020] FIG. 8 is a schematic diagram illustrating the polarization direction of the incident light entering the optical waveguide shown in FIG. 7 .

[0021] FIG9 is a schematic diagram of the polarization directions of the multiple light beams having the same propagation direction and different polarization directions that are emitted after two-dimensional pupil expansion through the optical waveguide shown in FIG7 .

[0022] FIG10 is a top view of a third embodiment of the optical waveguide proposed in an embodiment of the present application.

[0023] FIG. 11 is a schematic diagram of a partial structure in which a smooth inclined surface is provided in the coupling region shown in FIG. 1 .

[0024] FIG. 12 is a schematic diagram of a partial structure in which a smooth inclined surface is provided in the coupling region shown in FIG. 2 .

[0025] FIG13 is a K-vector diagram of the optical waveguide when the first diffraction microstructure and the second diffraction microstructure proposed in an embodiment of the present application are two-dimensional gratings.

[0026] FIG14 is a K-vector diagram of the optical waveguide when the first diffraction microstructure and the second diffraction microstructure proposed in an embodiment of the present application are one-dimensional gratings.

[0027] FIG15 is a top view of the optical waveguide proposed in an embodiment of the present application.

[0028] FIG16 is a perspective view of the outcoupling region of the optical waveguide according to an embodiment of the present application from a rear perspective. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0030] It should be understood that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0031] It should also be understood that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element through an intervening element.

[0032] The terms used in this specification are for the purpose of describing specific embodiments only and are not intended to limit this application. For example, the terms "first," "second," and so on are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, the term "first" or "second" may explicitly or implicitly include at least one of the features.

[0033] It should be further understood that the term "and / or" used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0034] 1-3 , an embodiment of the present application provides a speckle reduction assembly 100, comprising an optical waveguide 10, a coupling lens 20, and an optical fiber 30 arranged along an optical path. The optical waveguide 10 comprises an incoupling region 11 and an outcoupling region 12. The incoupling region 11 is configured to receive incident light and couple it into the optical waveguide 10 so that the light propagates within the optical waveguide 10. The outcoupling region 12 is provided with a first diffraction microstructure 13, which is configured to expand the pupil of the light to form multiple beams of light with the same propagation direction but different polarization directions, and couple the multiple beams of light out to the coupling lens 20. The coupling lens 20 is configured to couple the light out to the input end of the optical fiber 30, so as to combine the multiple beams of light with the same propagation direction but different polarization directions and output them from the output end of the optical fiber 30.

[0035] The speckle reduction assembly 100 of the embodiment of the present application can be used in a laser illumination device. By providing a first diffraction microstructure 13 in the outcoupling region 12 of the optical waveguide 10, the pupil of the incident laser is expanded to form multiple beams of light with the same propagation direction but different polarization directions. The outgoing pupil beams with different polarization directions are then recombined through a coupling lens 20 and an optical fiber 30, so that the final output light has multiple polarization directions, thereby reducing the coherence of the laser light and eliminating laser speckle in the image formed by the laser illumination device.

[0036] In some embodiments, the first diffractive microstructure 13 may be a one-dimensional grating, a two-dimensional grating, or a metasurface device. When the first diffractive microstructure 13 is a one-dimensional grating, the light can be dilated in one dimension. When the first diffractive microstructure 13 is a two-dimensional grating, the light can be dilated in two dimensions.

[0037] For example, the one-dimensional grating or the two-dimensional grating may be a surface relief grating or a holographic grating. The surface relief grating may be a straight groove grating, a tilted grating, a skewed tooth grating, or a blazed grating, etc.; the holographic grating may be a volume holographic grating, etc.

[0038] For example, the elements of a metasurface device can have different shapes and sizes, and more flexible and diverse diffraction effects can be achieved by precisely controlling the geometry and arrangement of the elements.

[0039] For example, when the first diffraction microstructure 13 is a two-dimensional grating, the principle of using an optical waveguide to implement two-dimensional pupil expansion of light to reduce coherence is as follows:

[0040] As shown in Figures 1, 7, and 9, laser light enters the optical waveguide 10 from the incoupling region 11 and propagates by total internal reflection. Upon reaching the outcoupling region 12, the first micro-diffraction structures 13 therein diffract the incident light into three different directions: total internal reflection direction R1, total internal reflection direction R2, and outcoupling direction R3. The outcoupling locations of the light in the outcoupling region 12 form a two-dimensional array, thereby expanding the original single incident light beam into multiple beams distributed in a two-dimensional manner, thereby achieving two-dimensional pupil expansion. Because the different outgoing light beams traverse different propagation paths, the number of total internal reflections and diffraction events varies, resulting in different polarization directions. In other words, incident light originally with a single polarization direction (as shown in Figure 8) propagates through the optical waveguide 10 and, upon exiting, becomes multiple beams with the same propagation direction but different polarization directions (as shown in Figure 9). Thus, after coupling and collimation, the light beams with different polarization directions become a single beam with poor coherence, thereby eliminating laser speckle in the image produced by the laser illumination device.

[0041] In some embodiments, the optical waveguide 10 can be made of glass or plastic and used in a laser lighting device. By coordinating the first diffraction microstructure 13, the coupling lens 20, and the optical fiber 30, a relatively simple structure is used without the need to introduce moving devices, thereby greatly improving the reliability and service life of the product. In addition, the coherence of the laser is fundamentally reduced, eliminating the necessary conditions for the generation of laser speckle, effectively eliminating the laser speckle in the image, and improving the quality of the final displayed image.

[0042] In some embodiments, the coupling lens 20 may be made of glass, quartz, optical glass, etc. The coupling lens 20 couples light into the optical fiber 30 to improve light transmission efficiency and reliability.

[0043] In some embodiments, as shown in Figures 1-5, the coupling region 11 is disposed on one side of the coupling region 12 in a first direction, the coupling lens 20 is disposed opposite the coupling region 12 in a second direction, the input end of the optical fiber 30 is disposed opposite the side of the coupling lens 20 facing away from the coupling region 12, and the output end of the optical fiber 30 extends in the second direction, with the first direction and the second direction being perpendicular. The first direction can be horizontal, and the second direction can be vertical. The speckle reduction assembly 100 of the present application has a simple structure, and the above-described layout makes it compact, reduces volume, and reduces cost.

[0044] In some embodiments, as shown in Figures 1, 2, 4, and 5, the optical waveguide 10 is further provided with a first reflective surface 14. The first reflective surface 14 is provided on a side of the outcoupling region 12 away from the coupling lens 20. The first reflective surface 14 is configured to reflect 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. The provision of the first reflective surface 14 can reduce light loss and improve luminous efficiency.

[0045] In some embodiments, as shown in Figures 1-6, 15, and 16, the optical waveguide 10 is further provided with a second reflective surface 15. The second reflective surface 15 is arranged obliquely at the edge of the outcoupling region 12 and is used to reflect light not outcoupled by the first diffractive microstructure 13 toward the coupling lens 20. The propagation direction of the light reflected by the second reflective surface 15 is the same as the propagation direction of the light outcoupled by the first diffractive microstructure 13. The provision of the second reflective surface 15 can further reduce light loss and improve luminous efficiency.

[0046] In some embodiments, the outcoupling region 12 has a first side 121 facing the incoupling region 11, a second side 122 opposite the first side 121, and a third side 123 and a fourth side 124 connected to and opposite the first and second sides 121 and 122. The optical waveguide 10 is provided with second reflective surfaces 15 on the second, third, and fourth sides 122, 123, and 124. The coordination of the three second reflective surfaces 15 on the second, third, and fourth sides 122, 123, and 124, along with the first reflective surface 14, further reduces light loss and improves luminous efficiency.

[0047] In some embodiments, as shown in Figures 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 inclined relative to the first reflecting surface 14; wherein the inclination angles of the three second reflecting surfaces 15 and the second reflecting surface 15 can be the same or different.

[0048] As shown in Figure 13, the light rays that are not coupled out by the first diffraction microstructure 13 of the outcoupling area 12 are a1, a2 and a2'. Therefore, inclined second reflection surfaces 15 can be set on the three sides of the outcoupling area 12 for the three types of light rays, so that the light rays a1, a2 and a2' are reflected by their respective second reflection surfaces 15, and the angles of the light rays all become a0. The inclination angles of the respective second reflection surfaces 15 can be determined based on simple geometric optical reflection principles.

[0049] As shown in Figures 15 and 16, the second reflection surfaces 15 corresponding to a1, a2 and a2' are respectively reflection surface 151, reflection surface 152 and reflection surface 153, and the first reflection surface 14 is a reflection surface set on the surface of the optical waveguide 10 away from the coupling lens 20 in the out-coupling area 12, and is used to reflect the diffracted light generated by the first diffraction microstructure 13 in the out-coupling area 10 and transmitted away from the coupling lens 20, so that this part of the light can be incident on the coupling lens 20 and coupled into the optical fiber 30.

[0050] In some embodiments, as shown in Figures 1 and 2, the coupling region 11 is provided with a smooth inclined surface 16 for reflecting incident light. The smooth inclined surface 16 is configured to reflect the incident light so that the reflected light propagates through total internal reflection within the optical waveguide 10. The provision of the smooth inclined surface 16 forms a certain angle with the incident light beam, thereby improving the coupling efficiency and stability of the light and allowing the reflected light to propagate through total internal reflection within the optical waveguide 10.

[0051] As an embodiment, as shown in FIG1 and FIG11 , the smooth inclined surface 16 can be tilted toward the direction of the decoupling region 12 and away from the coupling lens 20, that is, tilted downward. The optical waveguide 10 has two upper and lower surfaces 10a. The incident angle of the light transmitted in the optical waveguide 10 is θ1. The angle between the smooth inclined surface 16 and the surface 10a of the optical waveguide 10 is θ2. The incident angle of the light on the smooth inclined surface 16 is θ0. Wherein, arcsin(sinθ0 / n)+θ1=θ2, and n is the refractive index of the waveguide. When the incident light is incident perpendicular to the smooth inclined surface 16 of the coupling-in region 11, the above-mentioned arrangement enables the light to be totally reflected and propagated in the optical waveguide 10.

[0052] Snell's theorem shows that when the incident angle θ1 of light propagating within optical waveguide 10 is greater than or equal to arcsin(1 / n), the light will be totally reflected from the upper and lower surfaces 10a of optical waveguide 10 and will not be able to enter the air. In the embodiment shown in Figure 11, the incident light is incident perpendicular to the smooth inclined surface 16. The incident angle is defined as the angle between the light and the normal of the interface, that is, θ0 is 0°. In this way, the energy loss of the reflected light caused by the smooth inclined surface 16 is minimized, where θ1 ≥ arcsin(1 / n) and the angle between the smooth inclined surface 16 and the surface of optical waveguide 10 is θ2, where θ2 = θ1. If the incident light is incident on the surface of optical waveguide 10 at an angle, it will result in a greater loss of reflected light energy.

[0053] As another embodiment, as shown in Figures 2 and 12, the smooth inclined surface 16 can also be inclined toward the outcoupling region 12 and toward the coupling lens 20, that is, it can be arranged to be inclined upward. The optical waveguide 10 has two upper and lower surfaces 10a. The incident angle of light on the smooth inclined surface 16 is θ0, the incident angle of 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, it is reflected by the smooth inclined surface 16. The transmission angle of the light after reflection is such that the light is transmitted by total internal reflection within the optical waveguide 10.

[0054] According to Snell's theorem, when the incident angles θ0 and θ1 of light propagating within the optical waveguide 10 are both greater than or equal to arcsin(1 / n), the light will be totally reflected from the upper and lower surfaces 10a of the optical waveguide 10 and the smooth inclined surface 16, preventing it from entering the air. In the embodiment shown in FIG12 , the incident light is incident perpendicularly to the lower surface 10a of the optical waveguide 10. This minimizes the energy loss of the reflected light caused by the surface 10a of the optical waveguide 10. The angle between the smooth inclined surface 16 and the surface 10a of the optical waveguide 10 is θ2, where θ2 = θ0. If the incident light were to be incident at an angle on the smooth inclined surface 16, the reflected light energy loss would be greater.

[0055] In a specific application, the smooth inclined surface 16 can be coated with a reflective film on its surface, such as silver plating or aluminum plating, to reflect light.

[0056] In some embodiments, as shown in FIG13 , the K-vector diagram of the optical waveguide 10 is shown when the first diffraction microstructure 13 of the outcoupling region 12 is a two-dimensional grating. FIG12 is used as an example to illustrate the incoupling region 11 of the optical waveguide 10, where a0 represents an incident light perpendicular to the surface of the optical waveguide 10, a1 is a light that is totally reflected within the optical waveguide 10 at an incident angle θ1, and a2 and a2' are light that is totally reflected and propagates in two different directions within the optical waveguide 10 after a1 is diffracted by the two-dimensional grating of the outcoupling region 12. The two vectors K1 and K2 in FIG13 are the two grating vectors of the two-dimensional grating, and the directions of the grating vectors are the same as the directions of the two periods of the two-dimensional grating. In the figure, K1 = λ / d1 and K2 = λ / d2, where d1 and d2 are the two periods of the two-dimensional grating, and λ is the wavelength of the incident light.

[0057] In other embodiments, as shown in FIG14 , the K vector diagram of the optical waveguide 10 when the first diffraction microstructure 13 of the outcoupling region 12 is a one-dimensional grating, K1 is the grating vector of the outcoupling grating (first diffraction microstructure 13), and when the first diffraction microstructure 13 of the outcoupling region 12 is a one-dimensional grating, only one-dimensional pupil expansion can be achieved.

[0058] It should be noted that the coupling-in region 11 is not limited to the configuration of the smooth inclined surface 16 to enable the reflected light to propagate by total internal reflection within the optical waveguide 10. For example, in other embodiments, as shown in FIG4-FIG6 , the coupling-in region 11 is provided with a second diffraction microstructure 17, which is used to diffract the incident light so that the diffracted light enters the optical waveguide 10 and propagates by total internal reflection.

[0059] As an embodiment, as shown in FIG4 , the second diffractive microstructure 17 may be transmissive.

[0060] As another embodiment, as shown in FIG5 , the second diffractive microstructure 17 may also be reflective.

[0061] In some embodiments, the second diffraction microstructure 17 is a one-dimensional grating, a two-dimensional grating, or a metasurface device.

[0062] For example, the one-dimensional grating or the two-dimensional grating may be a surface relief grating or a holographic grating. The surface relief grating may be a straight groove grating, a tilted grating, a skewed tooth grating, or a blazed grating, etc.; the holographic grating may be a volume holographic grating, etc.

[0063] As shown in FIG13 , when the second diffraction microstructure 17 is a two-dimensional grating, K3 is the grating vector of the coupling-in grating (second diffraction microstructure 17), and the grating vector is aligned with the periodic direction of the coupling-in grating. In FIG13 , the grating vector length is K3 = λ / d3, where d3 is the period of the coupling-in grating and λ is the wavelength of the incident light. Here, a0 represents the incident light perpendicular to the surface of the optical waveguide 10, a1 is the light that is totally reflected within the optical waveguide 10 at an incident angle θ1, and a2 and a2′ are the light that is totally reflected and propagates in two different directions within the optical waveguide 10 after a1 is diffracted by the two-dimensional grating of the outcoupling region 12. K1 and K2 are the two grating vectors of the outcoupling grating (first diffraction microstructure 13), respectively. In the figure, K1 = λ / d1 and K2 = λ / d2, with d1 and d2 representing the two periods of the outcoupling grating, respectively.

[0064] Figure 14 shows the case where the second diffraction microstructure 17 is a one-dimensional grating. K1 is the grating vector of the outcoupling grating (first diffraction microstructure 13), and K3 is the grating vector of the incoupling grating (second diffraction microstructure 17).

[0065] For example, the elements of a metasurface device can have different shapes and sizes, and more flexible and diverse diffraction effects can be achieved by precisely controlling the geometry and arrangement of the elements.

[0066] In some embodiments, as shown in Figures 1, 2, 4, and 5, the speckle reduction assembly 100 further includes a collimator 40. The collimator 40 is disposed opposite the output end of the optical fiber 30. The collimator 40 is configured to receive the light coupled out of the optical fiber 30 and collimate the light for output. The collimator 40 collimates the light so that its propagation direction is aligned with the axial direction. Of course, the light 30 may also be directly connected to other interfaces for output without being connected to the collimator 40.

[0067] In some embodiments, in order to make the polarization directions of the outgoing lights more significantly different and further weaken the coherence of the light, a phase modulator 50 may be further provided between the outcoupling region 12 of the optical waveguide 10 and the coupling lens 20 .

[0068] As shown in FIG10 , the speckle reduction assembly 100 further includes a phase modulator 50, which is disposed between the outcoupling region 12 and the coupling lens 20. For example, the phase modulator 50 can be arranged in a two-dimensional array, and the two-dimensional phase modulator array elements can be wave plates, liquid crystals, or other devices with birefringence. Each phase modulation element covers a beam of outgoing light, and each phase modulation element has a different phase modulation amount (achieved by changing the thickness or rotation direction of the device). Different modulation effects can be applied to the outgoing light at different locations, thereby giving the outcoupled light beams a more random polarization direction.

[0069] In addition, the phase modulator unit can also be a device that can be modulated by voltage. For example, when the phase modulator unit includes liquid crystal, the phase modulator unit can change the polarization direction of light in real time as the applied voltage changes, so as to achieve temporal averaging of the speckle and better eliminate the speckle effect.

[0070] This embodiment of the present application also provides a laser lighting device comprising a laser source and the aforementioned speckle reduction assembly 100. The laser source is configured to emit laser light, and the speckle reduction assembly 100 is configured to receive the laser light emitted by the laser source and output light. The structure and function of the speckle reduction assembly 100 in the laser lighting device of this embodiment of the present application are the same as those in the aforementioned embodiment. For details, please refer to the description of the aforementioned embodiment and will not be repeated in this embodiment.

[0071] In some embodiments, the laser illumination device further includes a structural support for supporting the laser source, the optical waveguide 10, the coupling lens 20, the optical fiber 30, and the collimating lens 40, and a housing for accommodating the above components.

[0072] This embodiment of the present application also provides a display device, comprising a display device and the aforementioned laser illumination device. The display device is configured to receive light output by the laser illumination device for image display. The structure and function of the laser illumination device in the display device of this embodiment of the present application are the same as those in the aforementioned embodiment. For details, please refer to the description of the aforementioned embodiment and will not be repeated in this embodiment.

[0073] Those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples without mutual contradiction.

[0074] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present application, and such modifications or substitutions should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A speckle reduction assembly comprising an optical waveguide, a coupling lens, and an optical fiber arranged along an optical path, wherein the optical waveguide comprises an incoupling region and an outcoupling region, wherein the incoupling region is configured to receive incident light and couple it into the optical waveguide, so that the light propagates within the optical waveguide; The outcoupling region is provided with a first diffraction microstructure, which is used to expand the pupil of the light to form multiple beams of light with the same propagation direction and different polarization directions, and couple the multiple beams of light to the coupling lens; The coupling lens is used to couple the light to the input end of the optical fiber, so as to combine multiple light beams with the same propagation direction but different polarization directions and output them from the output end of the optical fiber.

2. The speckle reduction assembly according to claim 1, wherein: The first diffraction microstructure is a one-dimensional grating, a two-dimensional grating or a metasurface device.

3. The speckle reduction assembly of claim 1, wherein: The coupling-in region is arranged on one side of the outcoupling region in a first direction, the coupling lens and the outcoupling region are arranged opposite to each other along a second direction, the input end of the optical fiber is arranged opposite to the side of the coupling lens away from the outcoupling region, the output end of the optical fiber extends along the second direction, and the first direction is arranged perpendicular to the second direction.

4. The speckle reduction assembly of claim 1, wherein: The optical waveguide is also provided with a first reflecting surface, which is arranged on the side of the out-coupling region away from the coupling lens. The first reflecting surface is used to reflect the diffracted light generated by the first diffraction 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.

5. The speckle reduction assembly of claim 4, wherein: The optical waveguide is also provided with a second reflective surface, which is obliquely arranged at the edge of the outcoupling area and is used to reflect the light that is not coupled out by the first diffraction microstructure to the coupling lens, and the propagation direction of the light reflected by the second reflective surface is the same as the propagation direction of the light coupled out by the first diffraction microstructure.

6. The speckle reduction assembly of claim 5, wherein: The outcoupling region has a first side facing the incoupling region, a second side opposite to the first side, and a third side and a fourth side connected to the first side and the second side and opposite to each other; 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 reflecting surface is arranged to be inclined relative to the first reflecting surface.

8. The speckle reduction assembly of claim 1, wherein: The coupling-in region is provided with a smooth inclined surface for reflecting the incident light, and the smooth inclined surface is configured to reflect the incident light so that the reflected light can propagate through total reflection in the optical waveguide.

9. The speckle reduction assembly of claim 1, wherein: The coupling-in region is provided with a second diffraction microstructure, and the second diffraction microstructure is used to diffract the incident light so that the diffracted light enters the optical waveguide and propagates by total reflection.

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

11. The speckle reduction assembly of claim 1 , wherein: The speckle reduction assembly further includes a collimator, which is arranged opposite to the output end of the optical fiber and is used to receive the light coupled out of the optical fiber and collimate the light for output.

12. The speckle reduction assembly of claim 1, wherein: The speckle reduction component further includes a phase modulator, which is arranged between the outcoupling region and the coupling lens.

13. A laser lighting device comprising: a laser source, for emitting laser light; The speckle reduction assembly according to any one of claims 1 to 12, wherein the speckle reduction assembly is configured to receive the laser light emitted by the laser source and output light.

14. A display device comprising: display device; The laser lighting device according to claim 13, wherein the display device is used to receive light output by the laser lighting device to display an image.

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