Laser projection equipment

Abstract

The utility model relates to the field of projection display, and discloses laser projection equipment which comprises a light source, an illumination light path, a projection lens and an absorption device. The light source is used for emitting projection beams; the illumination light path comprises a spatial light modulator and a total reflection prism; the spatial light modulator is used for modulating an incident projection light beam and then emitting an image light beam and an invalid light beam; the absorption device is located on a light emitting path of the invalid light beam and comprises an optical lens group and a light absorption box; and the optical lens group is used for shrinking and shaping the invalid light beams and then emitting the invalid light beams into the light absorption box. The invalid light beams are guided into the light absorption box through the optical lens group for high-efficiency absorption, and the invalid light beams are prevented from entering the projection lens for imaging, so that the light energy of a black field picture in a projection picture is reduced, and the contrast ratio and the color layering sense of the projection picture are improved.

Description

Technical Field

[0001] This application relates to the field of projection display technology, and in particular to a laser projection device. Background Technology

[0002] A Digital Micromirror Device (DMD) is a spatial light modulation device whose core structure consists of an array of extremely small mirrors. Each micromirror can be independently flipped, and the incident light is spatially modulated pixelally by flipping at positive and negative angles. Micromirrors have an "On" state and an "Off" state. When a micromirror is in the "On" state, it flips at a certain angle, allowing its reflected light to enter the subsequent optical system; this reflected light is called the "on" beam. The on beam is projected through an imaging lens, and the corresponding pixel in the projected image is displayed as color or a bright color. When a micromirror is in the "Off" state, it flips at the opposite angle, causing its reflected light to deviate from the subsequent optical system. This reflected light is called the "off" beam and is not imaged by the projection lens; therefore, the corresponding pixel in the projected image is displayed as black.

[0003] Ineffective light beams may eventually enter the projection lens after multiple reflections and refractions, reducing the contrast of the projected image and affecting image quality.

[0004] To avoid this problem, it is usually necessary to install an absorption device in the equipment to eliminate invalid beams as much as possible, thereby improving the contrast and image quality of the projected image. Utility Model Content

[0005] This application discloses a laser projection device for efficiently absorbing invalid light beams, thereby preventing invalid light beams from entering the projection lens and improving the contrast and image quality of the projected image.

[0006] To achieve the above objectives, this application provides the following technical solution:

[0007] A laser projection device, comprising:

[0008] Light source, used to emit a projection beam;

[0009] An illumination optical path is located on the light-emitting side of the light source; the illumination optical path includes:

[0010] Spatial light modulation devices are used to modulate an incident projection beam to produce an output image beam and a non-existent beam; and

[0011] A total internal reflection prism, located on the light-emitting side of the spatial light modulator, is used to totally reflect the projection beam to the spatial light modulator and transmit the image beam and invalid beam emitted by the spatial light modulator.

[0012] A projection lens, located on the light-emitting side of the illumination optical path, is used to image the image beam; and

[0013] An absorption device is located in the light exit path of the ineffective light beam; the absorption device includes:

[0014] Light-absorbing box; and

[0015] An optical lens assembly is used to shrink and reshape the invalid beam before it is emitted into the light-absorbing box.

[0016] The projection device provided in this application includes a light source, an illumination optical path, a projection lens, and an absorption device. The light source emits a projection beam, and the illumination optical path, located on the light-emitting side of the light source, processes the projected light emitted from the light source and projects it onto the projection lens for imaging. Specifically, the illumination optical path includes a spatial light modulator and a total internal reflection prism. The total internal reflection prism is located between the spatial light modulator and the projection lens, and is used to totally reflect the projection beam incident on the prism back to the spatial light modulator. The spatial light modulator modulates the projection beam and emits an image beam and a non-image beam to the total internal reflection prism. The total internal reflection prism also transmits the image beam and the non-image beam. The image beam modulated by the spatial light modulator is the effective beam reflected by the micromirrors in the on state. The non-image beam modulated by the spatial light modulator is the beam reflected by the micromirrors in the off state. The absorption device is located on the light-emitting path of the non-image beam and is used to absorb as much of the non-image beam transmitted by the total internal reflection prism as possible. The absorption device includes an optical mirror assembly and a light-absorbing box. The optical lens assembly is used to reduce and reshape most of the invalid beam transmitted by the total internal reflection prism and send it into the light-absorbing box. Inside the light-absorbing box, the invalid beam is converted into heat energy and absorbed.

[0017] Therefore, in this embodiment, the invalid light beam is guided to the light-absorbing box through the optical lens group for efficient absorption, avoiding the invalid light beam from entering the projection lens for imaging, thereby reducing the light energy of the black field in the projected image and improving the contrast and image quality of the projected image.

[0018] In some embodiments, the absorption device further includes:

[0019] A light-blocking structure is located between the total internal reflection prism and the projection lens; the light-blocking structure includes:

[0020] A light-transmitting aperture is used to transmit the image beam to the projection lens; and

[0021] Mounting holes are used to mount the optical lens assembly;

[0022] The surface of the light-blocking structure is coated with a light-absorbing material.

[0023] In some embodiments, the light-absorbing box is light-sealed to the light-blocking structure;

[0024] The light-absorbing box includes:

[0025] An opening; the opening is located on the focal plane of the optical lens group; and the opening completely covers the spot formed by the ineffective beam on the focal plane of the optical lens group.

[0026] In some embodiments, the light-absorbing box is light-sealed to the light-blocking structure;

[0027] The light-absorbing box is equipped with a reflective element, which includes:

[0028] A reflecting surface is located on the focal plane of the optical mirror group, and the reflecting surface completely covers the spot formed by the invalid light beam on the focal plane of the optical mirror group.

[0029] In some embodiments, the inner wall of the light-absorbing box includes a plurality of surfaces, one of which is parallel to the side of the total reflection prism.

[0030] In some embodiments, the light-blocking structure includes:

[0031] An aperture is connected between the optical lens group and the light-absorbing box.

[0032] In some embodiments, the optical lens assembly includes:

[0033] A first lens, fixed to the mounting hole, is used to reduce and shape the invalid beam;

[0034] An orthographic prism for adjusting the direction of the ineffective light beam emitted through the first lens; comprising:

[0035] The first adhesive surface is glued to the side of the first lens away from the total reflection prism;

[0036] The second adhesive surface is connected to the first adhesive surface at an obtuse angle; and

[0037] Multiple first reflective surfaces are connected between the first adhesive surface and the second adhesive surface; and

[0038] The second lens, bonded to the second adhesive surface, is used to reduce and shape the invalid beam emitted from the second adhesive surface;

[0039] The outer surfaces of the plurality of first reflective surfaces are all coated with light-absorbing material.

[0040] In some embodiments, the absorption device further includes:

[0041] An optical waveguide element, optically sealed, is connected between the optical mirror assembly and the light-absorbing box to transmit the invalid light beam after beam shrinking and shaping by the optical mirror assembly to the light-absorbing box.

[0042] In some embodiments, a microstructure is provided on the inner wall of the light-absorbing box, the microstructure comprising:

[0043] Multiple micro-units, the multiple micro-units protruding or recessed into the inner surface of the light-absorbing box; and / or,

[0044] The inner wall of the light-absorbing box is coated with a light-absorbing material.

[0045] In some embodiments, the laser projection device further includes:

[0046] The housing; the light source, the illumination path, the projection lens, and the absorption device are all located inside the housing, and the outer surface of the light-absorbing box is at least partially thermally connected to the housing; and / or,

[0047] Heat dissipation component; the outer surface of the light-absorbing box is at least partially thermally connected to the heat dissipation component. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the structure of a projection system provided in an embodiment of this application;

[0049] Figure 2 This is a schematic diagram of another projection system provided in an embodiment of this application;

[0050] Figure 3 and Figure 4 All of these are schematic diagrams of a laser projection device provided in the embodiments of this application;

[0051] Figure 5 This is a schematic diagram of another laser projection device provided in an embodiment of this application;

[0052] Figure 6 This is a schematic diagram of another laser projection device provided in an embodiment of this application;

[0053] Figure 7 This is a schematic diagram of another laser projection device provided in an embodiment of this application;

[0054] Figure 8 This is a schematic diagram of another laser projection device provided in an embodiment of this application;

[0055] Figure 9 for Figure 8 Schematic diagram of the absorption principle of the invalid beam in the embodiment;

[0056] Figure 10 This is a schematic diagram of another laser projection device provided in an embodiment of this application;

[0057] Figure 11 for Figure 10 Schematic diagram of the absorption principle of the invalid beam in the embodiment;

[0058] Figure 12 This is a schematic diagram of another laser projection device provided in an embodiment of this application;

[0059] Figure 13 This is a schematic diagram of the structure of the inner wall of a light-absorbing box provided in an embodiment of this application;

[0060] Figure 14 This is a schematic diagram of another laser projection device provided in an embodiment of this application;

[0061] Figure 15 for Figure 14 Schematic diagram of the absorption principle of the invalid beam in the embodiment;

[0062] Figure 16 This is a schematic diagram of the structure of an optical lens assembly in an embodiment of this application;

[0063] Figure 17 This is a schematic diagram of another laser projection device provided in an embodiment of this application;

[0064] Figure 18 This is a schematic diagram of another laser projection device provided in an embodiment of this application;

[0065] Figure 19 This is a schematic diagram of another laser projection device provided in an embodiment of this application;

[0066] Figure 20 This is a schematic diagram of another laser projection device provided in an embodiment of this application;

[0067] Figure 21 This is a schematic diagram of another laser projection device provided in an embodiment of this application;

[0068] Icons: 1-Projection equipment; 2-Projection screen; 10-Laser projection equipment; 20-Projection screen; 100-Light source; 200-Illumination optical path; 300-Projection lens; 400-Absorption device; 500-Housing; 600-Heat dissipation component; 210-Illumination component; 220-Spatial light modulation device; 230-Total internal reflection prism; 410-Light blocking structure; 420-Optical lens group; 430-Light absorption box; 440-Aperture stop; 450-Light blocking sleeve; 460-Reflective element; 470-Optical waveguide element; 231- 232-Second total internal reflection prism; 411-Light transmission aperture; 412-Mounting hole; 421-First lens; 422-Oblique prism; 423-Second lens; 431-Opening; 432-Microstructure; 433-First sidewall; 434-Second sidewall; 435-Third sidewall; 436-Fourth sidewall; 437-Fifth sidewall; 4221-First adhesive surface; 4222-Second adhesive surface; 4223-First reflecting surface; 4321-Micro unit; 232a-Surface; 431a-Opening. Detailed Implementation

[0069] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application. In the description of the embodiments of this application, unless otherwise stated, " / " means "or", for example, A / B can mean A or B; "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships, for example, A and / or B can represent: A alone, A and B at the same time, and B alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0070] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature, and in the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more.

[0071] Projection display technology is a visual presentation method that converts images or video signals into visible light and shadow and projects them onto a flat screen or other surface. With the development of projection display technology, projection displays are gradually being applied to fields such as business activities, conferences and exhibitions, scientific education, military command, traffic management, centralized monitoring, and advertising and entertainment. Its advantages, such as large display size and clear display, are also suitable for the requirements of large-screen displays.

[0072] Figure 1 This is a schematic diagram of the structure of a projection system provided in an embodiment of this application.

[0073] like Figure 1 As shown, the projection system includes a projection device 1 and a projection screen 2. The projection screen 2 is located on the light-emitting side of the projection device 1. The audience faces the projection screen 2. The projection device 1 emits projection light, which enters the projection screen 2 and is reflected by the projection screen 2 before entering the viewer's eyes, thus allowing the viewer to see the projected image.

[0074] In this embodiment, the projection device 1 can be an ultra-short-throw laser projection device. Ultra-short-throw laser projection devices have the characteristics of small projection distance and large projection screen, making them very suitable for home use. To achieve better brightness and display effect, they can be used in conjunction with a projection screen 2.

[0075] The basic principle of projection display involves the transmission or reflection of light. Simply put, the light emitted by the light source inside the projection device 1 undergoes a series of processes, carries image information, and passes through or is reflected to the lens system. The lens then focuses and magnifies the light beam, ultimately forming a clear image that is projected onto the projection screen 2.

[0076] Current front-projection systems consist of a projection device 1 emitting projection light, which then strikes a projection screen 2. After reflection from the screen, the reflected light reaches the viewer's eye, allowing them to see the projected image. Using the projection system in conjunction with the projection screen 2 helps improve the gain and contrast of the projected image.

[0077] Figure 2 This is a schematic diagram of another projection system provided in an embodiment of this application.

[0078] like Figure 2 As shown, the projection system includes a laser projection device 10 and a projection screen 20. The laser projection device 10 emits a projection laser, which forms an image on the projection screen 20 to complete the projection display.

[0079] Figure 3 and Figure 4 These are all schematic diagrams of a laser projection device provided in the embodiments of this application.

[0080] like Figure 3 and Figure 4As shown, the laser projection device includes a light source 100, an illumination optical path 200, and a projection lens 300; the light source 100 is used to provide a projection beam toward the illumination optical path 200; the illumination optical path 200 is located on the light-emitting side of the light source 100 and is used to modulate the projection beam emitted by the light source 100; the projection lens 300 is located on the light-emitting side of the illumination optical path 200 and is used to image the beam modulated by the illumination optical path 200.

[0081] In one embodiment, the light source 100 includes a laser and a light combining element for providing a tri-color laser light source.

[0082] like Figure 4 As shown, the illumination optical path 200 includes an illumination component 210, a spatial light modulator 220, and a total reflection prism 230. The illumination component 210 is located on the light-emitting side of the light source 100 and is used to homogenize and shape the incident laser. The spatial light modulator 220 is located on the light-emitting side of the illumination component 210 and is used to modulate the incident laser before emission. The total reflection prism 230 is located between the illumination component 210 and the spatial light modulator 220 and is used to completely reflect the laser emitted from the illumination component 210 to the spatial light modulator 220 and transmit the laser modulated by the spatial light modulator 220.

[0083] In one embodiment, the illumination assembly 210 includes optical elements such as a lens group, a diffuser, and a compound eye lens, used for homogenizing and shaping the light source 100. The uniform projection beam emitted from the illumination assembly 210 is reflected by a total internal reflection prism 230 to a spatial light modulator 220, illuminating the spatial light modulator 220. The emitted light, spatially modulated by the spatial light modulator 220, is transmitted through the total internal reflection prism 230, separating the image beam from the invalid beam. The image beam passes through the projection lens 300 and forms an image on the projection screen, completing the projection display. The invalid beam exits from the side of the projection beam and is far from the projection lens 300. It is dispersed into the housing of the projection device through the total internal reflection prism 230, becoming stray light. After multiple reflections and refractions, the stray light is highly likely to enter the projection lens 300 and ultimately form an image on the projection screen, resulting in high brightness in black areas of the projected image and a decrease in the contrast of the projected image.

[0084] Figure 5 This is a schematic diagram of another laser projection device provided in an embodiment of this application.

[0085] Based on the above problems, embodiments of this application provide a laser projection device, such as... Figure 5As shown, a baffle 410 is located between the total internal reflection prism 230 and the projection lens 300. The total internal reflection prism 230 includes a first total internal reflection prism 231 and a second total internal reflection prism 232, used to separate the incident light from the outgoing light beams. The uniform illumination beam emitted from the illumination assembly 210 is totally reflected by the first total internal reflection prism 231 to the spatial light modulator 220, illuminating the spatial light modulator 220. The outgoing light modulated by the spatial light modulator 220 is then separated into an image beam and an invalid beam by the second total internal reflection prism 232. The baffle 410 includes a light-transmitting aperture 411; the light-transmitting aperture 411 is used to transmit the image beam formed by the spatial light modulator 220 to the projection lens 300; the surface of the baffle 410 is coated with a light-absorbing material to absorb the invalid beam.

[0086] In some embodiments, the baffle 410 is a flat, dark baffle that blocks the total reflection prism 230 and the projection lens 300. The baffle allows the image beam to pass through the reserved space, i.e. the light-transmitting hole 411, while absorbing all the invalid beams. The light-absorbing material on it converts light energy into heat energy, thus absorbing the invalid beams.

[0087] In one embodiment, the light-absorbing material is a dark-colored material coated on the surface of the baffle 410.

[0088] Because ineffective light beams are highly directional and have high energy, the dark coating cannot absorb all the light energy. Secondary reflected light may return through multiple reflections and refractions before entering the projection lens 300 and ultimately forming an image on the screen. This results in black areas still containing high light energy, significantly impacting image quality. Simultaneously, to prevent thermal deformation caused by continuous high-energy light beams, the baffle 410 typically has a certain thickness, creating new structural surfaces that complicate the propagation path of stray light and reduce the contrast of the projected image.

[0089] Figure 6 This is a schematic diagram of another laser projection device provided in an embodiment of this application.

[0090] like Figure 6 As shown, this application provides a laser projection device, including: a light source 100, an illumination optical path 200, a projection lens 300, and an absorption device 400;

[0091] Light source 100 is used to emit the projection beam;

[0092] The illumination optical path 200 is located on the light-emitting side of the light source 100; the illumination optical path 200 includes: a spatial light modulator 220 and a total reflection prism 230; the spatial light modulator 220 is used to modulate the incident projection beam and emit an image beam and an invalid beam; the total reflection prism 230 is located on the light-emitting side of the spatial light modulator 220 and is used to totally reflect the projection beam to the spatial light modulator 220 and transmit the image beam and invalid beam emitted by the spatial light modulator 220.

[0093] The projection lens 300 is located on the light-emitting side of the illumination optical path 200 and is used to image the image beam;

[0094] The absorption device 400 is located on the light exit path of the invalid beam; the absorption device 400 includes: an optical lens group 420 and a light-absorbing box 430; the optical lens group 420 is located on the side of the total internal reflection prism 230 facing the projection lens 300, and is used to reduce and shape the invalid beam before it is emitted into the light-absorbing box 430.

[0095] The laser projection device provided in this application includes a light source 100, an illumination optical path 200, a projection lens 300, and an absorption device 400. The light source 100 emits a projection beam, and the illumination optical path 200, located on the light-emitting side of the light source 100, processes the projection beam emitted from the light source 100 and projects it onto the projection lens 300 for imaging. Specifically, the illumination optical path 200 includes a spatial light modulator 220 and a total internal reflection prism 230. The total internal reflection prism 230 is located between the spatial light modulator 220 and the projection lens 300, and is used to totally reflect the projection beam incident on the total internal reflection prism 230 back to the spatial light modulator 220. The spatial light modulator 220 modulates the projection beam and emits an image beam and a non-image beam to the total internal reflection prism 230. The total internal reflection prism 230 also transmits the image beam and the non-image beam. The image beam modulated by the spatial light modulator 220 is an effective beam reflected by the micromirrors in the open state. The invalid beam modulated by the spatial light modulator 220 is the invalid beam reflected by the micromirrors in the off state. The absorption device 400 is located in the light exit path of the invalid beam and is used to absorb as much of the invalid beam transmitted by the total internal reflection prism 230 as possible. The absorption device 400 includes an optical mirror group 420 and an absorption box 430. The optical mirror group 420 is used to compress and shape most of the invalid beam transmitted by the total internal reflection prism 230 and emit it into the absorption box 430, where the invalid beam is converted into thermal energy and absorbed.

[0096] Therefore, in this embodiment, the invalid light beam is guided by the optical lens group 420 to the light absorption box 430 for high-efficiency absorption, avoiding the invalid light beam from entering the projection lens 300 for imaging, thereby reducing the light energy of the black field in the projected image and improving the contrast and color gradation of the projected image.

[0097] In some embodiments, such as Figure 6 As shown, the absorption device also includes a light-blocking structure located between the total reflection prism 230 and the projection lens 300; the light-blocking structure includes a light-transmitting hole 411 and a mounting hole 412; the light-transmitting hole 411 is used to transmit the image beam to the projection lens 300; the mounting hole 412 is used to mount the optical lens group 200; the surface of the light-blocking structure is coated with a light-absorbing material.

[0098] In one embodiment, such as Figure 6 As shown, the light-blocking structure includes a baffle 410. The baffle 410 is located between the total internal reflection prism 230 and the projection lens 300, a position that ensures it can filter and process the light transmitted from the total internal reflection prism 230. The baffle 410 includes a light-transmitting aperture 411. The image beam reflected by the spatial light modulator 220 in its open state enters the projection lens 300 through the light-transmitting aperture 411 to form an image. The baffle 410 also includes a mounting hole 412 for mounting the optical lens assembly 420. The position of the mounting hole 412 corresponds to the exit position of the invalid beam reflected by the spatial light modulator 220 in its off state from the total internal reflection prism 230.

[0099] The baffle 410 has mounting holes 412 to fix the optical lens assembly 420, eliminating the need for an additional fixing structure for the optical lens assembly 420 and making the entire absorption device 400 more compact. Furthermore, the mounting holes 412 allow the optical lens assembly 420 to be accurately aligned with the ineffective beam transmitted through the total internal reflection prism 230, ensuring that most of the ineffective beam is effectively guided to the light-absorbing box 430.

[0100] It should be noted that the optical lens group 420 can be fixed to the baffle 410 or to other structures.

[0101] To reduce stray light, the thickness of the baffle plate 410 should be as thin as possible while ensuring that the material does not undergo thermal deformation, in order to prevent light from being reflected off the sidewalls of the plate and causing unexpected stray light. The dark light-absorbing coating applied to the plate should have the highest possible absorption rate to reduce the reflectivity of stray light.

[0102] The optical lens group 420 is used to converge the ineffective beam emitted from the total reflection prism 230, thereby increasing the beam aperture angle while compressing the size of the ineffective beam.

[0103] Figure 7 This is a schematic diagram of another laser projection device provided in an embodiment of this application.

[0104] like Figure 7 As shown, in some embodiments, the light-blocking structure of the laser projection device provided in this application further includes an aperture 440 connected between the optical lens group 420 and the light-absorbing box 430.

[0105] like Figure 7As shown, the aperture 440 connects the optical lens group 420 and the light-absorbing box 430, ensuring that it can effectively intercept invalid light beams emitted from the side of the optical lens group 420, preventing invalid light beams from scattering, reducing the impact of invalid light beams on subsequent optical components, and ensuring that the converged invalid light beams can only exit from the aperture of the aperture 440. The aperture 440 can also reduce the possibility of invalid light beams directly entering the light-absorbing box 430, reducing the load on the light-absorbing box 430.

[0106] Understandably, the design of aperture 440 can be adjusted in size and shape to suit different configurations of optical lens group 420.

[0107] Figure 8 This is a schematic diagram of another laser projection device provided in an embodiment of this application.

[0108] like Figure 8 As shown, in some embodiments, the light-blocking structure of the laser projection device provided in this application further includes a light-blocking sleeve 450, which includes a first end and a second end arranged along the axial direction of the light-blocking sleeve 450; wherein the first end is connected to the aperture 440 and the second end is connected to the light-absorbing box 430.

[0109] The light-blocking sleeve 450 serves as a physical barrier, preventing leakage of the invalid light beam during its propagation between the aperture 440 and the light-absorbing box 430. In one embodiment, the light-blocking sleeve 450 may be made of a material with high light absorption to further reduce the reflection of the invalid light beam. In another embodiment, the inner surface of the light-blocking sleeve 450 may be specially treated, such as by adding microstructures or a light-absorbing coating, to enhance the absorption effect on the invalid light beam.

[0110] Figure 9 for Figure 8 A schematic diagram illustrating the absorption principle of an invalid light beam in this embodiment.

[0111] It should be noted that, Figure 9 Solid arrows represent image beams, and dashed arrows represent ineffective beams. The light-absorbing box 430 includes an opening 431. Ineffective beams are transmitted through the total internal reflection prism 230, converged by the optical lens group 420, and emitted into the light-absorbing box 430. Finally, they enter the light-absorbing box 430 through the opening 431 and are absorbed.

[0112] The design of the opening 431 is a key part of the absorption device 400, and its position and coverage directly affect the absorption effect of the invalid beam.

[0113] In some embodiments, such as Figure 8 and Figure 9 As shown, the aperture 431 is located on the focal plane of the optical lens group 420; and the aperture 431 completely covers the light spot formed by the invalid beam on the focal plane of the optical lens group 420.

[0114] The aperture 431 is located at the focal plane of the optical lens group 420, ensuring that it can directly capture the spot formed on the focal plane by the invalid beam. The design of the aperture 431 completely covering the spot reduces the possibility of the invalid beam escaping from the focal plane.

[0115] In one embodiment, the light-absorbing box 430 includes an opening 431. The opening 431 is located at the convergence point of the ineffective beam after passing through the optical lens group 420, and the size of the opening is slightly larger than the maximum spot size of the ineffective beam after convergence by the optical lens group 420, ensuring that the converged ineffective beam can all enter the light-absorbing box 430 through the opening 431. The inner wall of the light-absorbing box 430 is coated with a dark light-absorbing material with a rough surface. When the beam is incident on the material, most of the beam is absorbed and converted into heat energy, while the unabsorbed portion of the beam undergoes diffuse reflection at random angles.

[0116] Because the divergence angle of the converged ineffective beam is large, and the opening 431 of the light-absorbing box 430 is relatively small compared to the size of the light-absorbing box 430, the incident beam will undergo multiple random diffuse reflections inside the light-absorbing box 430, and will not be emitted in reverse from the opening 431, until all the light energy is absorbed by the light-absorbing coating and converted into heat energy, thus completing the entire process of guiding and absorbing the ineffective beam.

[0117] In some embodiments, to avoid processing errors affecting the optical path accuracy, the position of the aperture 431 relative to the optical mirror group 420 is adjustable to ensure that the aperture 431 covers the convergence point of the invalid beam through the optical mirror group 420.

[0118] In one embodiment, the position of the light-absorbing box 430 relative to the optical lens group 420 is adjustable.

[0119] In another embodiment, the light-absorbing box 430 includes a body and an opening baffle, the opening baffle being slidably mounted on the body; the opening baffle is provided with an opening 431.

[0120] To facilitate the back-focus design of the projection lens 300 and to simplify component stacking and size control, the optical length of the optical lens group 420 should be as short as possible, and the relative aperture D / f' should be as large as possible. Here, D is the effective aperture of the lens, and f' is the focal length of the lens. When a spherical lens design cannot meet the size requirements, it can be achieved through freeform surface design or microlens array structures.

[0121] Figure 10 This is a schematic diagram of another laser projection device provided in an embodiment of this application. Figure 11 for Figure 10 A schematic diagram illustrating the absorption principle of an invalid light beam in this embodiment. Figure 12 This is a schematic diagram of the structure of a light-absorbing box in another laser projection device provided in an embodiment of this application.

[0122] In some embodiments, such as Figures 10-12 As shown, the light-absorbing box 430 has an irregular shape. This irregular shape increases the reflection path length of the ineffective light beam within the light-absorbing box 430. The complex geometry reduces the possibility of the ineffective light beam escaping directly.

[0123] In some embodiments, the inner wall of the light-absorbing box 430 includes a plurality of surfaces, one of which is parallel to the side of the total reflection prism 230.

[0124] like Figure 12 As shown, the light-absorbing box 430 includes a first sidewall 433, a second sidewall 434, a third sidewall 435, a fourth sidewall 436, and a fifth sidewall 437 connected end to end. The first sidewall 433 and the fifth sidewall 437 cooperate to form the opening 431a of the light-absorbing box 430. In one embodiment, as... Figure 11 As shown, the optical lens group 420 is fixed at the opening of the aperture 440, and the aperture 440 is fixed at the opening 431a.

[0125] In one embodiment, the fifth sidewall 437 is parallel to the surface 232a of the second total reflection prism 232, and an acute angle is formed between the fifth sidewall 437 and the fourth sidewall 436, which allows the invalid light beam to be reflected multiple times within the light-absorbing box 430, thereby further improving the absorption efficiency.

[0126] Figure 13 This is a schematic diagram of the structure of the inner wall of a light-absorbing box provided in an embodiment of this application. In some embodiments, microstructures 432 are provided on the inner wall of the light-absorbing box 430; and / or, the inner wall of the light-absorbing box 430 is coated with a light-absorbing material.

[0127] like Figure 13 As shown, the microstructure 432 includes a plurality of microunits 4321, which protrude or are recessed on the inner surface of the light-absorbing box 430.

[0128] In one embodiment, microstructure 432 is formed on the inner surface of light-absorbing box 430. Through complex geometry, such as grooves and protrusions, the reflection path of light inside light-absorbing box 430 is increased, the probability of escape of invalid light beams is reduced, more light energy is absorbed, and the absorption rate of invalid light beams is improved.

[0129] In one embodiment, a light-absorbing material is coated on the inner surface of the light-absorbing box 430, exhibiting high absorptivity and low reflectivity, enabling it to efficiently absorb ineffective light beams and convert them into heat energy. Commonly used light-absorbing materials include carbon-based materials such as carbon black and metal oxides.

[0130] It should be noted that the microstructure 432 and the light-absorbing material can be used alone or in combination. Using them in combination can further improve the absorption efficiency and stability of the light-absorbing box 430.

[0131] like Figure 13 As shown, micro-unit 4321 protrudes from the inner surface of the light-absorbing box 430. Micro-unit 4321 can be of regular or irregular geometric shapes, such as cylindrical, pyramidal, or hemispherical. The protruding structure of micro-unit 4321 increases the propagation path of the ineffective light beam within the light-absorbing box 430, increasing the probability of light contacting the light-absorbing coating, thereby improving absorption efficiency. The protruding micro-unit 4321 can capture and guide part of the ineffective light beam, reducing the possibility of its direct escape. The surface shape and arrangement of micro-unit 4321 can effectively scatter light, further reducing the energy of the ineffective light beam.

[0132] Multiple micro-units 4321 and multiple micro-structures 432 are arranged in a reasonable manner, such as in an array or in a random arrangement, to ensure that light is reflected multiple times inside the light-absorbing box 430.

[0133] In some embodiments, such as Figure 10 and Figure 11 As shown, the light-absorbing box 430 is light-sealed to the light-blocking structure; the light-absorbing box 430 is provided with a reflective element 460, which includes a reflective surface; the reflective surface is located on the focal plane of the optical mirror group 420, and the reflective surface completely covers the light spot formed by the invalid light beam on the focal plane of the optical mirror group 420.

[0134] like Figure 10 and Figure 11 As shown, the optical lens group 420 is a lens used to collect diverging, ineffective light beams. The size and shape of this lens should be properly controlled so that the ineffective light beam can reach the focal plane after passing through the reflecting element 460, such as a mirror, and will not return to the second total internal reflection prism 232 via the lens. To meet this requirement, the lens size should be as small as possible, and a light-blocking stop 440 should surround its edge to prevent the ineffective light beam from returning. The mirror is used to deflect the light path so that the ineffective light beam enters the inner wall of the light-absorbing box 430.

[0135] The reflective surface reflects the ineffective beam from the focal plane to other parts of the absorber 430, such as the micro-unit 4321 or the light-absorbing coating, increasing the probability of absorption of the ineffective beam. The design of the reflective surface completely covering the light spot reduces the possibility of the ineffective beam escaping directly.

[0136] Since the optical lens group 420 is directly set at the opening 431a of the light-absorbing box 430, the distance between the upper surface of the light-absorbing box 430 and the second total internal reflection prism 232 is short, and the longitudinal dimension is relatively compact.

[0137] Figure 14 This is a schematic diagram of another laser projection device provided in an embodiment of this application. Figure 15 for Figure 14 A schematic diagram illustrating the absorption principle of an invalid light beam in this embodiment.

[0138] In some embodiments, such as Figure 14 and Figure 15 As shown, the absorption device 400 further includes an optical waveguide element 470 connected between the optical mirror group 420 and the light-absorbing box 430, for transmitting the invalid light beam after beam shrinking and shaping by the optical mirror group 420 to the opening 431.

[0139] In one embodiment, the optical waveguide element 470 includes an inner layer and a cladding layer covering the outer side of the inner layer. The refractive index of the cladding layer is lower than that of the inner layer, allowing light to propagate forward through repeated total internal reflection without overflowing through the cladding layer. Ultimately, the ineffective light beam is incident on the light-absorbing box 430 and absorbed within the light-absorbing box 430 by multiple reflections from the microstructure 432 and / or the light-absorbing coating.

[0140] The optical waveguide element 470 acts as a bridge, ensuring a more stable transmission path for the invalid beam from the optical mirror group 420 to the aperture 431. The optical waveguide element 470 efficiently transmits the beam-shrinking and shaping invalid beam from the optical mirror group 420 to the aperture 431, reducing transmission losses. Through the waveguide effect, it ensures that the invalid beam maintains a stable shape and direction during transmission. The design of the optical waveguide element 470 reduces the possibility of the invalid beam escaping during transmission.

[0141] The inner layer of the optical waveguide element 470 can be made of an optical material with low loss characteristics in the visible light band and a high thermal damage threshold, such as fused silica. The cladding of the optical waveguide element 470 should have a certain strength to prevent the optical waveguide element 470 from breaking under external force; and the cladding should be opaque to prevent light leakage caused by total internal reflection failure during transmission of the optical waveguide element 470.

[0142] Understandably, given the flexibility in shape of the optical waveguide element 470, the light-absorbing box 430 can be placed in any position. It is only necessary to design the shape of the optical waveguide element 470 to guide the invalid light beam to the desired position.

[0143] Figure 16 This is a schematic diagram of the structure of an optical lens group 420 in an embodiment of this application.

[0144] In some embodiments, such as Figure 16As shown, the optical lens assembly 420 includes: a first lens 421, an orthographic prism 422, and a second lens 423; the first lens 421 is located on the light-emitting side of the total internal reflection prism 230 and is used to reduce and shape the ineffective beam transmitted by the total internal reflection prism 230; the orthographic prism 422 is used to adjust the direction of the ineffective beam emitted through the first lens 421; the orthographic prism 422 includes: a first cemented surface 4221, a second cemented surface 4222, and a plurality of first reflecting surfaces 4223; the first cemented surface 4222... A second bonding surface 4221 is glued to the side of the first lens 421 facing away from the total reflection prism 230; the second bonding surface 4222 is connected to the first bonding surface 4221 at an obtuse angle; a plurality of first reflecting surfaces 4223 are connected between the first bonding surface 4221 and the second bonding surface 4222; the second lens 423 is glued to the second bonding surface 4222 and is used to reduce and shape the invalid beam emitted from the second bonding surface 4222; wherein, the outer surfaces of the plurality of first reflecting surfaces 4223 are coated with light-absorbing material.

[0145] The optical lens group 420 includes a first lens 421, an orthographic prism 422, and a second lens 423. Each lens has a specific function and they work together to effectively process invalid light beams.

[0146] The first lens 421 is located on the light-emitting side of the total internal reflection prism 230, ensuring that the invalid beam enters the subsequent lens with a suitable shape and direction. The first lens 421 can be made of a high-transmittance optical material to reduce the loss of the invalid beam during transmission.

[0147] The rhomboid prism 422 adjusts the direction of the invalid beam emitted through the first lens 421. All surfaces of the rhomboid prism 422, except for the first cemented surface 4221 and the second cemented surface 4222, are first reflecting surfaces 4223. The outer surface of each first reflecting surface 4223 is provided with a light-absorbing layer to absorb some of the invalid beam and reduce the possibility of escape. The rhomboid prism 422 can be made of an optical material with low scattering characteristics.

[0148] The second lens 423 ensures that the invalid beam enters subsequent processing components, such as the optical waveguide element 470, in the desired shape and direction. The second lens 423 can be made of an optical material with high transmittance and low scattering properties.

[0149] Figure 17 This is a schematic diagram of another laser projection device provided in an embodiment of this application; Figure 18 This is a schematic diagram of another laser projection device provided in an embodiment of this application; Figure 19 This is a schematic diagram of another laser projection device provided in an embodiment of this application; Figure 20 This is a schematic diagram of another laser projection device provided in an embodiment of this application; Figure 21This is a schematic diagram of another laser projection device provided in an embodiment of this application.

[0150] In some embodiments, such as Figures 17-21 As shown, the laser projection device also includes:

[0151] The housing 500; the light source 100, the illumination light path 200, the projection lens 300, and the absorption device 400 are all located inside the housing 500, and the outer surface of the light-absorbing box 430 is at least partially thermally connected to the housing 500; and / or,

[0152] Heat dissipation component 600; the outer surface of light-absorbing box 430 is at least partially thermally connected to heat dissipation component 600.

[0153] The housing 500 is the external protective structure of the entire laser projection device. The housing 500 provides physical protection for the internal optical components, preventing external dust, moisture, and other contaminants from affecting the device. At least part of the outer surface of the light-absorbing box 430 is thermally conductively connected to the housing 500, facilitating the effective conduction of heat generated inside the light-absorbing box 430 to the outside of the housing 500, achieving initial heat dissipation. The housing 500 can be made of materials with high thermal conductivity and good mechanical strength, such as aluminum alloy or magnesium alloy. The outer surface of the housing 500 can be specially treated, such as by adding heat dissipation fins, to further improve heat dissipation.

[0154] like Figure 17 As shown, the top surface of the light-absorbing box 430 is in contact with the housing 500 or connected via a thermally conductive element. The thermally conductive element can be thermally conductive adhesive or a thermally conductive sheet, etc.

[0155] like Figure 18 As shown, the third sidewall 435 and the fourth sidewall 436 of the light-absorbing box 430 are in contact with the housing 500 or connected through a heat-conducting element.

[0156] like Figure 19 As shown, the side and bottom surfaces of the light-absorbing box 430 are in contact with the housing 500 or connected through a heat-conducting element.

[0157] like Figure 20 As shown, the heat dissipation component 600 is at least partially thermally connected to the outer surface of the light-absorbing box 430. The heat dissipation component 600 can quickly conduct and dissipate the heat generated inside the light-absorbing box 430, ensuring that the light-absorbing box 430 maintains a stable operating temperature during long-term operation, while also improving the absorption efficiency of the light-absorbing box 430 for ineffective light beams. By effectively controlling the temperature of the light-absorbing box 430, the impact of thermal stress on the lifespan of the light-absorbing box 430 is reduced.

[0158] like Figure 21 As shown, the light-absorbing box 430 is located outside the housing 500, and the heat dissipation assembly 600 is in contact with part of the outer surface of the light-absorbing box 430 or connected through a heat-conducting element.

[0159] The heat dissipation component 600 can be made of a metal material with high thermal conductivity, such as copper or aluminum. The heat dissipation component 600 may include heat dissipation fins, heat pipes, or liquid cooling systems to meet the heat dissipation requirements in different scenarios.

[0160] The laser projection device provided in this application improves light absorption by adding an optical path design for the off-state invalid beam of the spatial light modulator 220, guiding and compressing the invalid beam into the absorption box. This application increases the light absorption rate and avoids the problem of secondary and multiple stray light pollution of dark scenes caused by thermal attenuation of the absorption rate, thus significantly improving the contrast of the projected display.

[0161] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this application without departing from the spirit and scope of this application. Therefore, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application also intends to include these modifications and variations.

Claims

1. A laser projection device, characterized by, include: Light source, used to emit a projection beam; The illumination optical path is located on the light-emitting side of the light source; The illumination optical path includes: Spatial light modulation devices are used to modulate an incident projection beam to produce an output image beam and a non-existent beam; and A total internal reflection prism, located on the light-emitting side of the spatial light modulator, is used to totally reflect the projection beam to the spatial light modulator and transmit the image beam and invalid beam emitted by the spatial light modulator. A projection lens, located on the light-emitting side of the illumination optical path, is used to image the image beam; and An absorption device is located in the light exit path of the ineffective light beam; the absorption device includes: Light-absorbing box; and An optical lens assembly is used to shrink and reshape the invalid beam before it is emitted into the light-absorbing box.

2. The laser projection device of claim 1, wherein, The absorption device further includes: A light-blocking structure is located between the total internal reflection prism and the projection lens; the light-blocking structure includes: A light-transmitting aperture is used to transmit the image beam to the projection lens; and Mounting holes are used to mount the optical lens assembly; The surface of the light-blocking structure is coated with a light-absorbing material.

3. The laser projection device according to claim 2, characterized in that, The light-absorbing box is light-sealed to the light-blocking structure; The light-absorbing box includes: An opening; the opening is located on the focal plane of the optical lens group; and the opening completely covers the spot formed by the ineffective beam on the focal plane of the optical lens group.

4. The laser projection device of claim 2, wherein, The light-absorbing box is light-sealed to the light-blocking structure; The light-absorbing box is equipped with a reflective element, which includes: A reflecting surface is located on the focal plane of the optical mirror group, and the reflecting surface completely covers the spot formed by the invalid light beam on the focal plane of the optical mirror group.

5. The laser projection device of claim 4, wherein, The inner wall of the light-absorbing box includes multiple surfaces, one of which is parallel to the side of the total reflection prism.

6. The laser projection device of claim 2, wherein, The light-blocking structure includes: An aperture is connected between the optical lens group and the light-absorbing box.

7. The laser projection device of claim 2, wherein, The optical lens assembly includes: A first lens, fixed to the mounting hole, is used to reduce and shape the invalid beam; An orthographic prism for adjusting the direction of the ineffective light beam emitted through the first lens; comprising: The first adhesive surface is glued to the side of the first lens away from the total reflection prism; The second adhesive surface is connected to the first adhesive surface at an obtuse angle; and Multiple first reflecting surfaces are connected between the first adhesive surface and the second adhesive surface; and a second lens is bonded to the second adhesive surface for reducing and shaping the invalid beam emitted from the second adhesive surface. The outer surfaces of the plurality of first reflective surfaces are all coated with light-absorbing material.

8. The laser projection device of claim 7, wherein, The absorption device further includes: An optical waveguide element, optically sealed, is connected between the optical mirror assembly and the light-absorbing box to transmit the invalid light beam after beam shrinking and shaping by the optical mirror assembly to the light-absorbing box.

9. The laser projection device of any one of claims 1-8, wherein, The inner wall of the light-absorbing box is provided with microstructures, the microstructures including: Multiple micro-units, the multiple micro-units protruding or recessed into the inner surface of the light-absorbing box; and / or, The inner wall of the light-absorbing box is coated with a light-absorbing material.

10. The laser projection device of any one of claims 1-8, wherein, The laser projection device also includes: The housing; the light source, the illumination path, the projection lens, and the absorption device are all located inside the housing, and the outer surface of the light-absorbing box is at least partially thermally connected to the housing; and / or, Heat dissipation component; the outer surface of the light-absorbing box is at least partially thermally connected to the heat dissipation component.

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