A holographic projection display device and smart speaker

Abstract

The application discloses a kind of holographic projection display equipment and smart speaker, which includes projection light source and cone lens;Light path is set between projection light source and cone lens on the light adjusting component;Wherein, projection light source is set in the top end side of cone lens;Light adjusting component is used to modulate the projection light beam output by projection light source to form multiple projection light beams respectively incident to each different side side of cone lens;Optical film layer is arranged on each side side of cone lens, respectively for the reflection output of incident projection light beam.In the present application, only one projection light source is used, and the light adjusting component is used to modulate the projection light beam output by the projection light source to form multiple projection light beams respectively incident to each different side side of the cone lens, thereby reducing the number of projection light sources, reducing the complexity of the optical structure of the equipment, and reducing the size of the space occupied by the projection light source, improving the realism of holographic projection.

Description

Technical Field

[0001] This invention relates to the field of holographic projection technology, and in particular to a holographic projection display device and a smart speaker. Background Technology

[0002] Holographic projection technology is a technique that uses the principles of interference and diffraction to record and reproduce a true three-dimensional image of an object. 360-degree holographic imaging is an imaging technique that uses holographic projection to suspend three-dimensional images in mid-air above a real-world scene, creating a surreal and dreamlike atmosphere. This imaging technology is widely used in science museums, museums, and exhibition venues. To achieve 360-degree holographic imaging, a four-sided window can be created, and four projection engines can project light into each window, allowing the four windows to output projected images from four different angles, thus achieving 360-degree projection. However, to achieve 360-degree projection imaging, at least four projection engines are required, resulting in a large image source area that is directly exposed to the viewer's line of sight, reducing the realism of the 3D projected image. Summary of the Invention

[0003] The purpose of this invention is to provide a holographic projection display device and a smart speaker that reduces the number of projection light sources, decreases the complexity of the device's optical structure and the size of the space occupied by the projection light sources, and enhances the realism of holographic projection.

[0004] To address the aforementioned technical problems, the present invention provides a holographic projection display device, comprising a projection light source and a conical lens; and a dimming component disposed in the optical path between the projection light source and the conical lens;

[0005] The projection light source is located on one side of the top of the conical lens;

[0006] The dimming component is used to modulate the projection beam output by the projection light source into multiple projection beams that are incident on different sides of the conical lens respectively.

[0007] Each side of the conical lens is provided with an optical film layer, which is used to reflect and output the incident projection beam.

[0008] In one optional embodiment of this application, the conical lens is a regular polygonal pyramidal lens;

[0009] The dimming component includes an optical diffraction element and a reflection component;

[0010] The optical diffraction element is used to diffract the projection beam output by the projection light source into multiple projection beams.

[0011] The reflective component is used to reflect and deflect at least one of the multiple projection beams output by the optical diffraction element, forming projection beams that are centrally symmetrical and output to the conical lens; and the central axis of symmetry of the multiple projection beams coincides with the central axis of the conical lens.

[0012] In one optional embodiment of this application, the optical diffraction element includes a waveguide element and a diffraction grating array disposed on the waveguide element;

[0013] The diffraction grating array is used to diffract and couple the projection beam output from the projection light source into the waveguide element, so that the projection beam is transmitted by total internal reflection within the waveguide element, and the projection beam transmitted within the waveguide element is coupled out by pupil expansion to form multiple projection beams.

[0014] In one optional embodiment of this application, the conical lens is a regular polygonal pyramidal lens; the dimming assembly includes an optical diffraction element for diffracting the projection beam output from the projection light source into multiple centrally symmetrical projection beams; and the symmetry central axis of the multiple projection beams coincides with the central axis of the conical lens.

[0015] In one alternative embodiment of this application, the optical diffraction element is a multiplexed grating.

[0016] In one optional embodiment of this application, the conical lens is a regular polygonal pyramidal lens; the dimming assembly includes an optical diffraction element and a drive motor;

[0017] The optical diffraction element includes multiple different diffraction regions arranged in a ring; the drive motor is used to drive the optical diffraction element to rotate so that each of the diffraction regions is sequentially located on the output light path of the projection light source.

[0018] When each of the diffraction regions is located sequentially in the output optical path of the projection light source, each of the diffraction regions is centrally symmetrical with respect to the projection beam output by the projection light source, and the axis of central symmetry coincides with the central axis of the conical lens.

[0019] The drive motor drives the optical diffraction element to rotate at a speed not less than a set rotation speed, so that the projected beams diffracted from each diffraction region form a visual persistence effect after being reflected by the side of the conical lens.

[0020] In one optional embodiment of this application, a magnifying lens group is provided between the dimming component and the conical lens.

[0021] In one optional embodiment of this application, the magnifying lens group includes a plurality of integrally formed lens units, each of which is located on the output optical path of the multiple projection beams output by the dimming component.

[0022] In one alternative embodiment of this application, the optical films on different sides of the conical lens are reflective diffraction grating films carrying different holographic information.

[0023] A smart speaker, characterized in that it includes a holographic projection display device as described in any of the preceding claims, for projecting and displaying a projected image.

[0024] The present invention provides a holographic projection display device and a smart speaker. The holographic projection display device includes a projection light source and a conical lens; a dimming component disposed in the optical path between the projection light source and the conical lens; wherein the projection light source is disposed on one side of the top of the conical lens; the dimming component is used to modulate the projection beam output by the projection light source into multiple projection beams that are incident on different sides of the conical lens respectively; each side of the conical lens is provided with an optical film layer, which is used to reflect and output the incident projection beams respectively.

[0025] The holographic projection display device in this application uses only one projection light source. On this basis, a dimming component is further set between the projection light source and the conical lens. The dimming component is used to modulate the projection beam output by the projection light source to form projection beams that are incident on different sides of the conical lens. This reduces the number of projection light sources required in the holographic projection display device, that is, reduces the complexity of the device's optical structure and reduces the space occupied by the projection light source, thereby improving the realism of the holographic projection. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the structure of the holographic projection display device provided in the embodiments of this application;

[0028] Figure 2 This is a schematic diagram of a first structure of an optical diffraction element provided in an embodiment of this application;

[0029] Figure 3 This is a schematic diagram of the optical path structure for deflecting and translating the projection beam provided in an embodiment of this application;

[0030] Figure 4 This is a schematic diagram illustrating the spatial position change of the projection beam deflection and translation provided in an embodiment of this application.

[0031] Figure 5 This is a schematic diagram of a second structure of an optical diffraction element provided in an embodiment of this application;

[0032] Figure 6 This is a schematic diagram of a third structure of an optical diffraction element provided in an embodiment of this application;

[0033] Figure 7 This is a schematic diagram of a fourth structure of an optical diffraction element provided in an embodiment of this application;

[0034] Figure 8 Another structural schematic diagram of the holographic projection display device provided in the embodiments of this application;

[0035] In the attached diagram: 10 is the projection light source, 20 is the conical lens, 30 is the dimming component, 31 is the optical diffraction element, 310 is the waveguide element, 311 is the first diffraction grating, 312 is the second diffraction grating, 313 is the third diffraction grating, 314 is the fourth diffraction grating, 315 is the coupling grating, 316 is the diffraction region, 32 is the reflection component, 321 is the plane mirror, and 40 is the magnifying lens group. Detailed Implementation

[0036] The core of this invention is to provide a holographic projection display device and a smart speaker, which reduces the number of projection light sources to a certain extent, that is, reduces the complexity of the device's optical structure and reduces the space occupied by the projection light sources, thereby enhancing the realism of holographic projection.

[0037] To enable those skilled in the art to better understand the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] like Figures 1 to 8 As shown, Figure 1 This is a schematic diagram of the structure of the holographic projection display device provided in the embodiments of this application; Figure 2 This is a schematic diagram of a first structure of an optical diffraction element provided in an embodiment of this application; Figure 3 This is a schematic diagram of the optical path structure for deflecting and translating the projection beam provided in an embodiment of this application; Figure 4 This is a schematic diagram illustrating the spatial position change of the projection beam deflection and translation provided in an embodiment of this application. Figure 5This is a schematic diagram of a second structure of an optical diffraction element provided in an embodiment of this application; Figure 6 This is a schematic diagram of a third structure of an optical diffraction element provided in an embodiment of this application; Figure 7 This is a schematic diagram of a fourth structure of an optical diffraction element provided in an embodiment of this application; Figure 8 Another structural schematic diagram of the holographic projection display device provided in the embodiments of this application.

[0039] In one specific embodiment of this application, the holographic projection display device may include:

[0040] Projection light source 10 and conical lens 20; dimming assembly 30 disposed in the optical path between projection light source 10 and conical lens 20;

[0041] The projection light source 10 is located on one side of the top of the conical lens 20;

[0042] The dimming assembly 30 is used to modulate the projection beam output from the projection light source 10 into four projection beams that are incident on different sides of the conical lens 20 respectively.

[0043] Each side of the conical lens 20 is provided with an optical film layer, which is used to reflect and output the incident projection beam.

[0044] It should be noted that, for the conical lens 20 in this application, a centrally symmetrical conical lens structure can be preferred; for example, it can be a regular polygonal pyramidal lens, or a frustum conical lens structure, etc. Of course, in practical applications, the conical lens 20 can also adopt a non-centrally symmetrical frustum conical structure; as long as the projection beam output by the projection light source 10 is modulated by the modulation component 30 to form multiple projection beams, and each projection beam is incident on different sides of the conical lens 20 at an appropriate angle, so that the user can view the projected image from different sides of the conical lens 20.

[0045] It is understandable that when the conical lens 20 has a centrally symmetrical structure, the projected light rays incident on each side of the conical lens 20 are also required to be centrally symmetrical.

[0046] For ease of understanding and explanation, the cone lens 20 will be described as a regular square pyramid lens in the following embodiments. However, it is understood that the implementation methods in the various embodiments of this application can also be implemented in other regular polygonal pyramid lenses, frustum conical lenses, or even other lens structures, which will not be repeated in this application.

[0047] like Figure 1 As shown, in Figure 1In the illustrated embodiment, the conical lens 20 is a regular square pyramidal lens. In the holographic projection display device, the projection light source 10, the dimming component 30, and the conical lens 20 are arranged sequentially. In practical applications, the projection light source 10, the dimming component 30, and the conical lens 20 can be arranged sequentially along the vertical direction. The projection light source 10 mainly outputs projection light. The dimming component 30 is located on the output light path of the projection light source 10 and can split the single projection light output by the projection light source 10 into four projection beams by means of beam splitting or other methods. These four projection beams are respectively incident on the four sides of the conical lens 20. The four sides of the conical lens 20 are also four windows for realizing the output of projection light. Each side is provided with an optical film layer, thereby reflecting and outputting the four projection beams respectively. Thus, the projection light is output from four different directions of the conical lens 20, so that the projected image can be viewed from four different positions.

[0048] Understandable Figure 1 The four sides of the conical lens 20 are centrally symmetrically distributed. Correspondingly, the four projection beams output by the dimming assembly 30 after modulating the projection beam from the projection light source 10 should also be centrally symmetrical, with the central axis of symmetry coinciding with the central axis of the conical lens 20. Furthermore, the top of the conical lens 20 refers to the pointed end of the conical lens 20, and the projection light source 10 and the dimming assembly 30 are located on one side of the top of the conical lens 20. In practical applications, the top of the conical lens 20 can be located at either the top or the bottom of the conical lens 20; this application does not specifically limit this.

[0049] Of course, in practical applications, the cone lens 20 can also be a four-sided pyramidal lens that is not centrally symmetrical among its four sides. In this case, the relative positional relationship between the four projection beams output by the dimming component 30 should correspond to the positional relationship between the four sides of the cone lens 20. Ultimately, as long as the four projection beams can be incident on the four sides respectively, and the user can also view the projected image through the four different sides.

[0050] Furthermore, this embodiment uses only one projection light source 10, which can be any one of LBS light source, DMD optical engine, LCoS light source, or LCD light source. Based on this, this embodiment uses the dimming component 30 to modulate the single projection beam output by the projection light source 10 into four projection beams to replace four light sources. This reduces the number of projection light sources 10 to a certain extent, thereby reducing the overall cost and energy consumption of the device. It also reduces the area occupied by the projection light source 10, which can, to a certain extent, prevent the projection light source 10 from falling into the viewer's line of sight, thus improving the realism of the projected image.

[0051] Based on the above discussion, the dimming component 30 in this application can be implemented in various different ways. In one optional embodiment of this application, taking the conical lens 20 as a regular polygonal pyramidal lens as an example, the dimming component 30 may include:

[0052] Optical diffraction element 31 and reflective component 32;

[0053] The optical diffraction element 31 is used to diffract the projection beam output from the projection light source 10 into four projection beams.

[0054] The reflective component 32 is used to reflect and deflect at least one of the four projection beams output by the optical diffraction element 31 to form four centrally symmetrical projection beams output to the conical lens 20; and the central axis of symmetry of the four projection beams coincides with the central axis of the conical lens 20.

[0055] like Figure 1 As shown, the optical diffraction element 31 in this embodiment can specifically be a diffraction grating. This optical diffraction element 31 diffracts the projection beam, splitting it so that a single projection beam ultimately forms four different projection beams. Furthermore, because it is required that the four projection beams ultimately incident on the four sides of the square pyramid lens be centrally symmetrical, the spatial orientation and position of the four projection beams diffracted by the optical diffraction element 31 may not meet the requirement of central symmetry. Therefore, the reflection component 32 can be further used to reflect and deflect at least one of the four projection beams, thereby ensuring that the four projection beams ultimately satisfy the relative positional relationship of central symmetry.

[0056] It is understandable that in practical applications, there are also many different ways to implement the optical diffraction element 31, and the layout structure of the corresponding reflection component 32 is not the same for different types of optical diffraction elements 31; even different types of optical diffraction elements 31 do not necessarily need to be equipped with the reflection component 32.

[0057] like Figure 2 As shown, in an optional embodiment of this application, the conical lens 20 is a regular polygonal pyramidal lens; the optical diffraction element 31 includes a waveguide element 310 and a diffraction grating array disposed on the waveguide element 310;

[0058] The diffraction grating array is used to diffract and couple the projection beam output from the projection light source 10 into the waveguide element 310, so that the projection beam is transmitted by total internal reflection within the waveguide element 310, and the projection beam transmitted within the waveguide element 310 is coupled out by pupil expansion to form multiple projection beams.

[0059] Reference Figure 2 ,exist Figure 2 In the illustrated embodiment, the conical lens 20 is taken as a regular square pyramidal lens. The diffraction grating array includes four diffraction gratings sequentially arranged on one side of the waveguide element 310. When the projection beam output from the projection light source 10 is incident on the first diffraction grating 311 on the waveguide element 310, the first diffraction grating 311 performs partial transmission (transmittance can be 0.25) and partial reflection diffraction on the projection beam. After the projection beam diffracted by the first diffraction grating 311 undergoes one total internal reflection transmission within the waveguide element 310, it is incident on the second diffraction grating 312. The second diffraction grating 312 performs partial transmission diffraction on the incident projection beam towards the waveguide element. The projected beam is output outside the waveguide element 310 (diffraction rate can be 0.3), while another part is reflected; the projected beam output after reflection by the second diffraction grating 312 undergoes total internal reflection transmission within the waveguide element 310 and then enters the third diffraction grating 313; the third diffraction grating 313 also performs partial transmission diffraction of the incident projected beam to output outside the waveguide element 310 (diffraction rate can be 0.5) and partial reflection; the projected beam reflected by the third diffraction grating 313 undergoes total internal reflection transmission within the waveguide element 310 and then enters the fourth diffraction grating 314, which performs transmission diffraction output of the entire incident projected beam.

[0060] Based on the diffraction effect of the first to fourth diffraction gratings 311 to 314 on the incident projection beam, the projection beam is finally split and output from the optical interface of the four diffraction gratings in a one-dimensional pupil form, thereby forming four projection beams. In practical applications, the principal ray directions of the four projection beams output from the waveguide element 310 after passing through the four diffraction gratings can be parallel to each other or have relative angles. This embodiment does not specifically limit this, as long as the reflection component 32 can deflect and reflect each projection beam to make the four projection beams centrally symmetrical.

[0061] like Figure 1 and Figure 2 As shown, in Figure 1 and Figure 2 In the illustrated embodiment, the principal rays of the four projection beams output by the optical diffraction element 31 are parallel, coplanar, and arranged side-by-side. Therefore, in practical applications, the reflection component 32 can be used to deflect and translate the two beams located in the middle of the four projection beams in opposite directions, thereby making the four projection beams centrally symmetrical. The reflection component 32 may include two pairs of plane mirrors 321, such as... Figure 3 As shown, Figure 3The diagram illustrates the optical path for a projected beam to be deflected and translated by a pair of plane mirrors 321; the two plane mirrors 321 in each pair are parallel to each other, and each pair of plane mirrors 321 is used to deflect and translate a projected beam; for example... Figure 4 As shown, Figure 4 The diagram shows the relative positions of the four projection beams in a top-down view on a plane perpendicular to the principal ray direction of the four projection beams. The four dashed circles represent the positions of the four projection beams' spots, and the two dashed circles represent the spots of the two middle projection beams after being deflected and translated by the plane mirror 321. (The last sentence appears to be incomplete and possibly refers to a different topic.) Figure 3 and Figure 4 The first of the two plane mirrors 321 reflects a projection beam, causing the projection beam to deviate from the original plane where the four projection beams were located. The second plane mirror then reflects and deflects the beam again, so that the principal ray of the projection beam reflected from the second plane mirror is parallel to the principal ray before it was incident on the first plane mirror, but its spatial position is translated by a certain distance. The two projection beams located in the middle of the four projection beams are deflected and translated in the same way but in opposite directions, ultimately making the four projection beams centrally symmetrical.

[0062] Of course, in Figure 3 and Figure 4 The embodiment shown is illustrated by taking the example that the principal rays of the four projected beams diffracted by the optical diffraction element 31 are parallel to each other. In practical applications, such as... Figure 8 As shown, the four projected beams output by the optical diffraction element 31 are not necessarily parallel to each other. To address this, multiple mirrors can modulate and deflect each projected beam according to the actual optical path, ultimately maintaining the central symmetry between the four projected beams. This will not be elaborated in detail in this application.

[0063] The above embodiments are merely one specific implementation of the dimming component 30. In practical applications, the dimming component 30 in this application does not necessarily need to include the reflection component 32. In another optional embodiment of this application, the conical lens 20 is a regular polygonal pyramidal lens; the dimming component 30 may further include:

[0064] The optical diffraction element 31 is used to diffract the projection beam output from the projection light source 10 into multiple centrally symmetrical projection beams; and the central axis of symmetry of the multiple projection beams coincides with the central axis of the conical lens 20.

[0065] The optical diffraction element 31 in this embodiment can also be a diffraction grating. However, the difference is that in this embodiment, the diffraction grating structure can be set according to actual needs, so that the projection beam output by the projection light source 10 is split into multiple centrally symmetrical projection beams.

[0066] like Figure 5 As shown, in Figure 5 In the illustrated embodiment, the conical lens 20 is a regular square pyramidal lens; the optical diffraction element 31 may include four diffraction gratings arranged sequentially. When the projection beam output from the projection light source 10 is incident on the first diffraction grating 311, the first diffraction grating 311 can partially diffract and partially transmit the projection beam. The transmitted projection beam is incident on the second diffraction grating 312, and is partially diffracted and partially transmitted by the third diffraction grating 313. The projection beam transmitted by the third diffraction grating 313 is incident on the fourth diffraction grating 314 and produces a diffracted output. Based on this, the diffracted rays output by the four diffraction gratings are output in four centrally symmetrical directions, that is, four projection beams in different directions are formed.

[0067] Understandably, in Figure 4 In the embodiment shown, there is a certain spacing between the four diffraction gratings. In practical applications, the four diffraction gratings can be composite gratings that are sequentially attached and stacked.

[0068] Furthermore, in embodiments where the dimming assembly 30 does not include the reflection assembly 32, the implementation is not limited to the one described above, such as... Figure 6 As shown, in Figure 6In the illustrated embodiment, the conical lens 20 is a regular square pyramidal lens; the optical diffraction element 31 may include a waveguide element 310, a coupling grating 315 disposed on the waveguide element 310, and four symmetrically arranged diffraction gratings. When the projection beam output from the projection light source 10 is incident on the coupling grating 315, the coupling grating 315 diffracts the projection beam to form projection beams diffracted in two different directions; wherein, the first projection beam undergoes total internal reflection at the optical interface of the waveguide element 310 and is incident on the first diffraction grating 311, the first diffraction grating 311 partially diffracts the projection beam and couples it out from the waveguide element 310, and also partially reflects it. After undergoing total internal reflection at the optical interface of waveguide element 310, the beam is incident on the second diffraction grating 312 and diffracted out by the second diffraction grating 312. Similarly, the second projection beam, after being diffracted by coupling grating 315, undergoes total internal reflection at the optical interface of waveguide element 310 and is incident on the third diffraction grating 313. The third diffraction grating 313 also partially diffracts the second projection beam to couple it out of waveguide element 310, and a portion is reflected and undergoes total internal reflection again at the optical interface of waveguide element 310 before being incident on the fourth diffraction grating 314 and diffracted out of waveguide element 310 by the fourth diffraction grating 314. In addition, by reasonably setting the grating structure of the four diffraction gratings, the projection beams diffracted by the four diffraction gratings can be centrally symmetrical, thereby meeting the optical path requirements, and the deflection of the projection beam does not need to be achieved by the reflection component 32 in the entire optical path.

[0069] Based on the above discussion, in all the above embodiments, the diffraction function of the diffraction grating is used to split the projection beam and ultimately form four symmetrically distributed projection beams. The diffraction grating is a non-geometric optical element, which can minimize the space occupied by the entire display device while achieving beam splitting. However, in practical applications, it is not limited to using optical diffraction element 31 to split the projection beam. For example, prisms, beam splitters, and other optical devices can be used to split the projection beam multiple times to ultimately form four mutually symmetrical projection beams, which can also achieve the technical solution of this application. Therefore, this application does not impose specific limitations on this approach.

[0070] Furthermore, in all the above embodiments, the projection beam is split into four projection beams, and the four projection beams are symmetrically incident on the four sides of the conical lens 20; however, in practical applications, the dimming component 30 does not necessarily split the projection beam. For example... Figure 7 As shown, in another optional embodiment of this application, the conical lens 20 is a regular polygonal pyramidal lens; the dimming assembly 30 may include:

[0071] Optical diffraction element 31 and drive motor;

[0072] The optical diffraction element 31 includes multiple different diffraction regions 316 arranged in a ring; the drive motor is used to drive the optical diffraction element 31 to rotate so that each diffraction region 316 is sequentially located on the output light path of the projection light source 10.

[0073] When each diffraction region 316 is located sequentially in the output optical path of the projection light source 10, each diffraction region 316 is centrally symmetrical with respect to the projection beam output by the projection light source 10, and the axis of central symmetry coincides with the central axis of the conical lens 20.

[0074] The drive motor drives the optical diffraction element 31 to rotate at a speed not less than the set rotation speed, so that the projected beam output by each diffraction region 316 forms a visual persistence effect after being reflected by the side of the conical lens 20.

[0075] like Figure 7 As shown, in Figure 7 In the illustrated embodiment, the conical lens 20 is again taken as a regular square pyramidal lens; the optical diffraction element 31 can be a disk structure and is divided into four fan-shaped regions of the same size, each fan-shaped region corresponding to a diffraction region 316; when the drive motor drives the optical diffraction element 31 to rotate around its center, the four fan-shaped diffraction regions 316 rotate sequentially to be located on the output optical path of the projection light source 10, and when the projection beam output by the projection light source 10 is incident on different diffraction regions 316 respectively, the direction of the output beam after diffraction in each diffraction region 316 is also different. Thus, by reasonably setting the diffraction direction of each diffraction region 316 to the projection beam, the direction of the diffraction output of each diffraction region 316 to the projection beam can be made centrally symmetrical; such as Figure 7 As shown, Figure 7 The straight line with an arrow drawn from the diffraction region 316 shows the direction of the output beam after the diffraction region 316, which is currently located on the output optical path of the projection light source 20, diffracts the projection beam. The other three dashed lines with arrows represent the three different directions of the output projection beam when the other three diffraction regions 361 are located on the output optical path of the projection light source 20.

[0076] Based on this, the rotation speed of the optical diffraction element 31 is controlled by the drive motor, so that the rotation speed of the optical diffraction element 31 is not less than the set speed. As a result, each diffraction region 316 on the optical diffraction element 31 diffracts and outputs a projection beam from the side of the conical lens 20 to form a projection image. Before the projection image disappears due to visual persistence, the diffraction region 316 rotates again to the output light path of the projection light source 10 and diffracts and outputs a projection beam again. As a result, the projection beams diffracted and output by each diffraction region 316 are output from different sides of the conical lens 20, forming a stable projection image from a visual perspective.

[0077] Compared to embodiments that split the projection beam, in this embodiment, the optical power of the projection beam output from each side of the conical lens 20 is approximately equal to the optical power of the projection beam output from the projection light source 10. In other words, in this embodiment, without increasing the optical power of the projection light source 10, the high brightness of the projection image formed by the projection beams output from each side of the conical lens 20 can be guaranteed.

[0078] The above embodiments illustrate various optical path structure implementations of the dimming component 30; however, it is understood that in practical applications, the dimming component 30 in this application is not limited to the above implementations, for example, the above... Figure 7 In the optical diffraction element 31 shown, the four diffraction regions 316 are not limited to four diffraction regions 316 arranged in a ring. They can also be four diffraction regions 316 arranged in a straight line. The four diffraction regions 316 are moved along a straight line by a drive motor, so that each diffraction region 316 passes through the output optical path of the projection light source 10 in turn. For example, the dimming component 30 can also be a component formed by combining a beam splitter and a diffraction grating. It can also include components of other structural types, which will not be listed in detail in this application.

[0079] Based on the above embodiments, in another optional embodiment of this application, a magnifying lens group 40 may be further provided between the dimming component 30 and the conical lens 20.

[0080] Considering that after the dimming component 30 modulates the projection beam output from the projection light source 10 into four symmetrically distributed projection beams, the projection image formed by each projection beam directly incident on the side of the conical lens 20 may be relatively small; therefore, in this embodiment, a magnifying lens group 40 is further provided between the dimming component 30 and the conical lens 20. The magnifying lens group 40 may include only a convex lens, a concave lens, or a combination of a convex lens and a concave lens, as long as it can magnify the projection image formed by the projection beam. This application does not impose specific restrictions on this.

[0081] Alternatively, the magnifying lens group 40 in this application may further include multiple integrally formed lens units, each lens unit being located on the output optical path of each projection beam output by the dimming component 30, thereby enabling the multiple lens units to independently expand and amplify the corresponding projection beams, thus magnifying the projection images output from each side of the conical lens 20.

[0082] Furthermore, based on the above embodiments, such as Figure 5 , Figure 7 and Figure 8 As shown, the four main rays of the projection beams output by the projection light source 10 can be parallel to each other or have an angle between them after being modulated by the dimming component 30. In practical applications, the magnifying lens group 40 can further include a collimating lens, and the dimming component 30 is set on the focal plane of the collimating lens, so that the four projection beams output by the dimming component 30 form four parallel projection beams after passing through the collimating lens.

[0083] Based on the above discussion, an optical film layer is provided on each side of the conical lens 20; the optical film layer can be a reflective film with reflective function.

[0084] Alternatively, the optical films on different sides of the conical lens 20 can also be reflective diffraction grating films carrying different holographic information.

[0085] It is understood that the reflective diffraction grating film in this embodiment is also a volume holographic grating carrying information about the three-dimensional contour of the object. When the projection beam output by the projection light source 10 is incident on the volume holographic grating as a reference beam, the three-dimensional contour image of the object can be restored and displayed. In practical applications, the optical films on different sides of the conical lens 20 can be volume holographic gratings that record the contour shape information of different sides of the same object, thereby providing users with a more realistic and three-dimensional holographic image.

[0086] In summary, the holographic projection display device of this application uses only one projection light source. On this basis, a dimming component is further set between the projection light source and the conical lens. The dimming component is used to modulate the projection beam output by the projection light source to form four projection beams that are incident on four different sides of the conical lens respectively. This reduces the number of projection light sources required in the holographic projection display device, that is, reduces the complexity of the device's optical structure, reduces the space occupied by the projection light source, and improves the realism of the holographic projection.

[0087] This application also provides an embodiment of a smart speaker, which includes a holographic projection display device as described in any of the preceding claims for projecting and displaying a projected image.

[0088] In practical applications, the holographic projection display device on a smart speaker can project an image that dynamically changes with the music (or other audio) output by the smart speaker, allowing the animation and music to work in sync and enhancing the user experience.

[0089] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that the elements inherent in a process, method, article, or apparatus that includes a list of elements are included. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. Additionally, portions of the technical solutions provided in the embodiments of this application that are consistent with the implementation principles of corresponding technical solutions in the prior art have not been described in detail to avoid excessive elaboration.

[0090] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A holographic projection display device, characterized in that, Includes a projection light source and a conical lens; a dimming assembly disposed in the optical path between the projection light source and the conical lens; The projection light source is located on one side of the top of the conical lens; The dimming component is used to modulate the projection beam output by the projection light source into multiple projection beams that are incident on different sides of the conical lens respectively. Each side of the conical lens is provided with an optical film layer, which is used to reflect and output the incident projection beam. The conical lens is a regular polygonal pyramidal lens; the dimming assembly includes an optical diffraction element and a drive motor; The optical diffraction element includes multiple different diffraction regions arranged in a ring; the drive motor is used to drive the optical diffraction element to rotate so that each of the diffraction regions is sequentially located on the output light path of the projection light source. When each of the diffraction regions is located sequentially in the output optical path of the projection light source, each of the diffraction regions is centrally symmetrical with respect to the projection beam output by the projection light source, and the axis of central symmetry coincides with the central axis of the conical lens. The drive motor drives the optical diffraction element to rotate at a speed not less than a set rotation speed, so that the projected beams diffracted from each diffraction region form a visual persistence effect after being reflected by the side of the conical lens.

2. The holographic projection display device as described in claim 1, characterized in that, A magnifying lens group is provided between the dimming component and the conical lens.

3. The holographic projection display device as described in claim 2, characterized in that, The magnifying lens group includes multiple lens units integrally formed, and each lens unit is located on the output optical path of each projection beam output by the dimming component.

4. The holographic projection display device as described in claim 1, characterized in that, The optical films on different sides of the conical lens are reflective diffraction grating films carrying different holographic information.

5. A smart speaker, characterized in that, Includes the holographic projection display device as described in any one of claims 1 to 4, used for projecting and displaying projected images.

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