Illumination device and laser projection device

Abstract

The present application discloses an illumination device and a laser projection device, belonging to the field of laser technology. The illumination device includes a lens assembly, a reverse total internal reflection prism assembly, and a light valve arranged in sequence along the optical path direction of the illumination device; the lens assembly includes a first lens and a second lens arranged in sequence along the optical path direction. After receiving the light beam, the first lens guides the light beam to the second lens, and the second lens guides the received light beam to the reverse total internal reflection prism assembly and outputs it to the light valve through the reverse total internal reflection prism assembly, and the light valve outputs the received light beam to the lens; the reverse total internal reflection prism assembly includes a reverse total internal reflection prism and a compensation prism located on the incident light surface of the reverse total internal reflection prism, and the compensation prism is used to reduce the spot size of the incident light beam. The problem of the relatively large volume of the illumination device in the related art is solved, and the effect of reducing the volume of the illumination device is achieved.

Description

Technical Field

[0001] This application relates to the field of laser technology, and particularly relates to an illumination device and a laser projection device. Background Art

[0002] Currently, ultra-short throw projectors can project large-sized images at short projection distances, and are widely used due to their high space utilization rate and small volume. A digital micromirror device (DMD) is a digital micromirror element, and usually the short side of the DMD is used to receive the incident light to reduce the volume of the illumination device.

[0003] An illumination device in the related art includes a light homogenizing component, a lens assembly, a plane mirror, and a compensation prism. Since the DMD can better receive the optical path when there is a certain angle between the DMD and the light homogenizing component, the lens assembly, the plane mirror in the lens assembly, and the compensation prism arranged parallel to the DMD are sequentially arranged between the light homogenizing component and the DMD. After the optical path enters from the light homogenizing component, it passes through some lenses in the lens assembly, is reflected by the plane mirror to some lenses and the compensation prism arranged parallel to the DMD, and then is reflected from the compensation prism to the DMD, and enters the projection lens through the DMD for imaging.

[0004] The above illumination device has a large volume. Summary of the Invention

[0005] Embodiments of this application provide an illumination device and a laser projection device, which can solve the problem that the structure of the illumination device in the related art is relatively complex. The technical solutions are as follows:

[0006] On the one hand, an illumination device is provided, and the illumination device includes:

[0007] The illumination device includes a lens assembly, a reverse total internal reflection prism assembly, and a DMD arranged in sequence along the optical path direction of the illumination device;

[0008] The lens assembly includes a first lens and a second lens arranged in sequence along the optical path direction. After receiving the light beam, the first lens guides the light beam to the second lens, and the second lens guides the received light beam to the reverse total internal reflection prism assembly and outputs it to the DMD through the reverse total internal reflection prism assembly, and the DMD outputs the received light beam to the lens;

[0009] The reverse total internal reflection prism assembly includes a reverse total internal reflection prism and a compensation prism located on the incident light surface of the reverse total internal reflection prism, and the compensation prism is used to reduce the spot size of the incident light beam.

[0010] Optionally, the reverse total internal reflection prism is a triangular prism, and the light incident surface of the reverse total internal reflection prism is the bottom surface;

[0011] The compensating prism is a triangular prism, and the bottom surface of the compensating prism is attached to the bottom surface of the reverse total internal reflection prism.

[0012] Optionally, the illumination device further includes a galvanometer scanner, which is located between the reverse total internal reflection prism assembly and the light valve. The light beam guided by the reverse total internal reflection prism assembly to the light valve passes through the galvanometer scanner and then shoots at the light valve. The light valve guides the received light beam to the galvanometer scanner. The galvanometer scanner processes the light beam emitted by the light valve and then guides it to the reverse total internal reflection prism, and is guided by the reverse total internal reflection prism to the lens.

[0013] Optionally, the lens assembly further includes a third lens, and the first lens, the third lens, and the second lens are arranged in sequence along the optical path direction.

[0014] Optionally, the optical axis of the first lens is parallel to the first optical axis of the light beam incident on the first lens, the optical axis of the third lens is parallel to the first optical axis, the optical axis of the second lens has a first included angle with the first optical axis, and the included angle between the optical axis of the second lens and the light incident surface of the reverse total internal reflection prism is greater than the included angle between the optical axis of the third lens and the light incident surface of the reverse total internal reflection prism. Among them, the first lens is used to reduce the spot size of the light beam and collimate the light beam, the third lens is used to reduce the spot size of the light beam, and the second lens is used to balance the field optical path.

[0015] Optionally, the reverse total internal reflection prism includes a space surrounded by a first side surface, a bottom surface, and a second side surface. The second lens guides the light beam to the bottom surface and shoots it into the total internal reflection prism. The light beam passes through the first side surface and exits the total internal reflection prism. The light beam exiting from the first side surface is reflected by the light valve and then enters the bottom surface of the total internal reflection prism from the first side surface, is reflected by the bottom surface and shoots at the second side surface, and passes through the second side surface and shoots at the lens;

[0016] The compensating prism is located on the bottom surface of the total internal reflection prism, and the compensating prism is used to compensate the field optical path.

[0017] Optionally, the effective focal length of the first lens is F1, the effective focal length of the third lens is F2, and the effective focal length of the second lens is F3;

[0018] F1 satisfies the formula 0.1 < |F1 / F| < 0.5;

[0019] F2 satisfies the formula 0.8 < |F2 / F| < 1.6;

[0020] The F3 satisfies the formula 0.3 < |F3 / F| < 0.8;

[0021] where F is the effective focal length of the lighting device.

[0022] Optionally, the lighting device further includes a light homogenizing component, and the light homogenizing component is located on the light incident side of the lens assembly.

[0023] Optionally, the light homogenizing component includes a light guide.

[0024] On the other hand, a laser projection device is provided, including the lighting device described in the first aspect.

[0025] The beneficial effects brought by the technical solution provided by the embodiments of the present application are as follows:

[0026] A lens assembly, a reverse total internal reflection prism assembly, and a light valve are sequentially arranged along the optical path direction of the lighting device. The lens assembly includes a first lens and a second lens sequentially arranged along the optical path direction. The reverse total internal reflection prism assembly includes a reverse total internal reflection prism and a compensation prism located on the light incident surface of the reverse total internal reflection prism. After the first lens receives the light beam, it guides the light beam to the second lens. The second lens guides the received light beam to the compensation prism. After the light beam passing through the compensation prism reduces the spot size, it is output to the light valve through the reverse total internal reflection prism. The light valve reflects the light beam towards the reverse total internal reflection prism, and the reverse total internal reflection prism guides the light beam to the lens. The compensation prism refracts the light beam while reducing the spot size, so that the area of the light received by the reverse total internal reflection prism can be reduced, thereby reducing the size of the reverse total internal reflection prism and reducing the length of the lighting device along the direction of the system optical axis. Moreover, the lens assembly, the reverse total internal reflection prism assembly, and the light valve are sequentially arranged along the direction of the system optical axis, and there is no need to set a reflector, reducing the volume of the lighting device. The problem of the large volume of the lighting device in the related art is solved, and the effect of reducing the volume of the lighting device is achieved. Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0028] Figure 1 It is a schematic diagram of the implementation environment related to the embodiments of the present application;

[0029] Figure 2 is Figure 1 a schematic structural diagram of the lighting device shown;

[0030] Figure 3 is a schematic structural diagram of a lighting device provided by an embodiment of the present application;

[0031] Figure 4 is a schematic structural diagram of another lighting device provided by an embodiment of the present application;

[0032] Figure 5 is a comparison diagram of a reverse total internal reflection prism assembly provided by an embodiment of the present application;

[0033] Figure 6 is a schematic structural diagram of a rear working distance provided by an embodiment of the present application;

[0034] Figure 7 is a schematic structural diagram of a galvanometer in a laser projector in the related art;

[0035] Figure 8 is a schematic structural diagram of a laser projection device provided by an embodiment of the present application.

[0036] Through the above-mentioned drawings, specific embodiments of the present application have been shown, and there will be more detailed descriptions hereinafter. These drawings and textual descriptions are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. Detailed Embodiments

[0037] To make the objectives, technical solutions, and advantages of the present application clearer, the following will further describe the embodiments of the present application in detail with reference to the drawings.

[0038] Figure 1 is a schematic diagram of an implementation environment related to an embodiment of the present application. The implementation environment may include an ultra-short throw projector 10 and a projection screen 20.

[0039] The laser projector 10 may include a lighting device 11 and a projection lens 12. The lighting device 11 is used to provide a light source to the projection lens 12, and the projection lens 12 is used to project a preset pattern onto the projection screen 20 according to the light source provided by the lighting device 11.

[0040] The projection screen 20 is used to carry the pattern projected by the projection lens 12. The projection screen 20 may be made of various materials, such as polyvinyl chloride (PVC), metal, fiberglass, and glass beads, etc., and the embodiments of the present application do not make any limitations.

[0041] Figure 2It is a schematic structural diagram of a lighting device in the related art. The lighting device 11 includes a light homogenizing component 111, a lens assembly 112, a plane mirror 113, a total internal reflection prism 114, and a light valve 115. The lens assembly 112 includes a first lens 1121, a second lens 1122, and a third lens 1123. When the light beam 116 exits from the light homogenizing component 111, it passes through the first lens 1121 to the second lens 1122 which are vertically arranged along the direction of the optical axis of the system. At this time, since the short side of the light valve is used to receive the incident light, the plane mirror 113 is arranged to reflect the light beam 116 to change the direction of the light beam 116. The short-side incident mode of the light valve means that the shorter side in the thickness direction of the light valve receives the incident light, which can reduce the thickness of the entire lighting device. The light beam 116 after changing the direction enters the third lens 1123, then vertically exits from the third lens 1123 to the total internal reflection prism 114, and is then reflected from the total internal reflection prism 114 to the light valve 115, and exits from the light valve 115 to the projection lens.

[0042] Due to the arrangement of the plane mirror in the above lighting device, the optical path is an inclined optical path, and each lens is also arranged obliquely along the optical path, resulting in a relatively large overall volume and thickness of the lighting device. Other components in the entire optical engine system are arranged in cooperation with this lighting device, thus making the entire ultra-short throw projector relatively large in volume and thick in thickness.

[0043] The embodiment of the present application provides a lighting device and a laser projection device, which can solve the problems in the above related art.

[0044] Figure 3 It is a schematic structural diagram of a lighting device provided by the embodiment of the present application. The structure of the lighting device 30 is as follows:

[0045] A lens assembly 31, a reverse total internal reflection prism assembly 32, and a light valve 33 are sequentially arranged along the direction of the first optical axis 40 of the optical path of the lighting device 30.

[0046] The lens assembly 31 includes a first lens 311 and a second lens 312 arranged sequentially along the optical path direction. After receiving the light beam, the first lens 311 guides the light beam to the second lens 312, and the second lens 312 guides the received light beam to the reverse total internal reflection prism assembly 32, and outputs it to the light valve 33 by the reverse total internal reflection prism assembly 32, and the light valve 33 outputs the received light beam to the lens.

[0047] The reverse total internal reflection prism assembly 32 includes a reverse total internal reflection prism 321 and a compensation prism 322 located on the light incident surface of the reverse total internal reflection prism 321. The compensation prism 322 is used to reduce the spot size of the incident light beam.

[0048] In summary, the embodiment of the present application provides an illumination device, including a lens assembly, a reverse total internal reflection prism assembly, and a light valve arranged in sequence along the optical path direction of the illumination device. The lens assembly includes a first lens and a second lens arranged in sequence along the optical path direction. The reverse total internal reflection prism assembly includes a reverse total internal reflection prism and a compensation prism located on the light incident surface of the reverse total internal reflection prism. After the first lens receives the light beam, it guides the light beam to the second lens. The second lens guides the received light beam to the compensation prism. After the light beam passing through the compensation prism reduces the spot size, it is output to the light valve through the reverse total internal reflection prism. The light valve reflects the light beam towards the reverse total internal reflection prism, and the reverse total internal reflection prism guides the light beam to the lens. While reducing the spot size, the compensation prism refracts the light beam, so that the area of the light received by the reverse total internal reflection prism can be reduced, thereby reducing the size of the reverse total internal reflection prism and decreasing the length of the illumination device along the direction of the system optical axis. Moreover, the lens assembly, the reverse total internal reflection prism assembly, and the light valve are arranged in sequence along the direction of the system optical axis, without setting a reflector, reducing the volume of the illumination device. This solves the problem of the large volume of the illumination device in the related art and achieves the effect of reducing the volume of the illumination device.

[0049] As Figure 4 shown, it is a schematic structural diagram of another illumination device 30 provided by the embodiment of the present application.

[0050] Optionally, the reverse total internal reflection prism 321 includes a space enclosed by a first side surface m1, a bottom surface m2, and a second side surface m3. The second lens 312 guides the light beam to the bottom surface m2 and injects it into the total internal reflection prism 321. The light beam passes through the first side surface m1 and exits the total internal reflection prism 321. The light beam exiting from the first side surface m1 is reflected by the light valve 33 and then enters the bottom surface m2 of the total internal reflection prism 321 from the first side surface m1. After being reflected by the bottom surface m2, it is directed towards the second side surface m3 and passes through the second side surface m3 and is directed towards the lens 50. The compensation prism 322 is located on the bottom surface m2 of the total internal reflection prism 321, and the compensation prism 322 is used to compensate the field optical path. A triangular prism is a prism made of a transparent material with a triangular cross-section in optics. A reverse total internal reflection prism (English: Reverse Total Internal Reflection, abbreviation: RTIR) is an isosceles right triangular prism, where the hypotenuse of the isosceles right triangular prism is the light incident surface for receiving the incident light beam, and this light incident surface is also the bottom surface m2 of the reverse total internal reflection prism 321. The reverse total internal reflection prism 321 can guide the light beam emitted from the lens assembly 31 to the light valve 33, and then reflect the light beam reflected back from the light valve 33 to the projection lens 50. The bottom surface of the compensation prism 322 and the bottom surface m2 of the reverse total internal reflection prism 321 can be glued, and the specific connection method is not limited in the embodiment of the present application.

[0051] Figure 5A comparison diagram of a reverse total internal reflection prism assembly provided by an embodiment of the present application. In the figure, the triangular prism within the dashed box is the reverse total internal reflection prism without the compensation prism, and the dashed beam is the beam path directly entering the reverse total internal reflection prism without the compensation prism from the lens assembly. h1 is the length required for the bottom surface of the reverse total internal reflection prism without the compensation prism to receive the beam. The triangular prism within the solid line box in the figure is the reverse total internal reflection prism 321 with the compensation prism 322 added. The beam emitted from the lens assembly first enters the compensation prism 322. The compensation prism 322 reduces the spot size of the incident beam and refracts the beam. The beam with the reduced spot size and the changed optical path direction through refraction enters the reverse total internal reflection prism 321. h2 is the length required for the bottom surface of the reverse total internal reflection prism with the compensation prism to receive the beam. h1 is greater than h2. Since the optical path is refracted along the optical axis system direction, the area of the beam received by the reverse total internal reflection prism 321 is reduced, so the size of the reverse total internal reflection prism 321 can be reduced. The higher the refractive index of the compensation prism 322, the smaller the size of the reverse total internal reflection prism 321 can be. The refractive index of the compensation prism 322 is related to the material of the compensation prism, and the specific material is not limited in this application.

[0052] Figure 6 A schematic structural diagram of the rear working distance provided by an embodiment of the present application. The rear working distance refers to the distance from this surface to the image surface if the last surface of the system is glass, that is, the distance between the last lens of the projection lens 50 and the light valve 33 in the optical engine system, that is, Figure 6 the sum of the lengths of a and b in. When the size of the reverse total internal reflection prism 321 is reduced, the light valve 33 and the projection lens 50 move relative positions towards the reverse total internal reflection prism 321, the lengths of a and b decrease, and the sum of the lengths of a and b decreases, thereby reducing the rear working distance of the projection device. And since the size of the reverse total internal reflection prism 321 is reduced, the light valve 33 moves towards the reverse total internal reflection prism 321, and at the same time, the overall length of the lighting device 30 along the optical axis 40 direction is reduced, shrinking the volume of the lighting device 30. In addition, since the rear working distance is reduced, the size of the projection lens 50 can be reduced accordingly, that is, the volume of the entire projection device is reduced. The specific proportion of the size reduction of the projection lens can refer to the related technology, and it will not be elaborated in this embodiment of the present application.

[0053] Optionally, the lighting device further includes a galvanometer 35, which is located between the reverse total internal reflection prism assembly 32 and the light valve 33. The light beam guided by the reverse total internal reflection prism assembly to the light valve passes through the galvanometer and then shoots towards the light valve. The light valve guides the received light beam to the galvanometer, and the galvanometer processes the light beam emitted by the light valve and then guides it to the reverse total internal reflection prism, and is then guided by the reverse total internal reflection prism to the lens. The galvanometer is usually a flat piece of glass, and through high-frequency vibration, the misaligned transmission of the light beam is achieved. In the related art, in order to improve the resolution of an ultra-short throw projector with an LED light source, an ultra-short throw projector with a laser light source is used. In this application, a galvanometer is added to the ultra-short throw projector with a laser light source, which can make the resolution of the ultra-short throw projector higher than the resolution of the light valve 33, so that the resolution is improved from 720P in the related art to 1080P.

[0054] In the laser projectors in the related art, the galvanometer 35 is usually placed between the reverse total internal reflection prism and the projection lens, as Figure 7 shown. When the galvanometer is arranged in the lighting device, the galvanometer structure member 351 provides power for the galvanometer 35, so that the galvanometer 35 can deflect to improve the resolution of the projection device. The galvanometer structure member 351 includes many components such as a circuit board, so the volume of the galvanometer structure member 351 is larger than the volume of the galvanometer 35. If the galvanometer 35 and the structure member 351 are arranged between the reverse total internal reflection prism 321 and the projection lens 50, the circuit board of the galvanometer structure member 351 interferes with the circuit board of the light valve 33, so the final imaging of the light beam will be affected. In the embodiment of this application, as Figure 4 shown, the galvanometer 35 is arranged between the reverse total internal reflection prism assembly 32 and the light valve 33. When the light beam shoots from the lens assembly 31 to the light valve 33, since it is an illumination light beam, it is not affected by the deflection of the galvanometer 35 when passing through the galvanometer 35. When the light beam enters the light valve 33 and then passes through the galvanometer 35 again to reach the projection lens 50, the light beam is an imaging light beam. At this time, the deflection of the galvanometer 35 can improve the imaging resolution.

[0055] Optionally, the lens assembly 31 further includes a third lens 313, and the first lens 311, the third lens 313, and the second lens 312 are arranged in sequence along the optical path direction. Among them, the second lens 312 is the closest to the reverse total internal reflection prism assembly 32. The first lens 311 can be a spherical lens or an aspherical lens; the second lens 312 can be a spherical lens or an aspherical lens; the third lens 313 can be a spherical lens or an aspherical lens. The specific selection of the lens specifications is not limited in the embodiment of this application.

[0056] Optionally, the optical axis of the first lens 311 is parallel to the first optical axis of the light beam incident on the first lens, the optical axis of the third lens 313 is parallel to the first optical axis 40, the optical axis of the second lens 312 has a first included angle with the first optical axis 40, and the included angle between the optical axis of the second lens 312 and the light incident surface of the reverse total internal reflection prism 321 is greater than the included angle between the optical axis of the third lens 313 and the light incident surface of the reverse total internal reflection prism 321. The first lens 311 is used to reduce the spot size of the light beam and collimate the light beam. The third lens 313 is used to reduce the spot size of the light beam. The second lens 312 is used to balance the field optical path. That is, the first lens 311 is arranged perpendicular to the first optical axis 40, the third lens 313 is arranged perpendicular to the first optical axis 40, and the second lens 312 is arranged obliquely to the first optical axis 40. The light beam is incident from the second lens 312 on the reverse total internal reflection prism assembly 32. If the second lens 312 is arranged perpendicular to the first optical axis 40, to ensure that the light beams between the second lens 312 and the reverse total internal reflection prism assembly 32 do not interfere with each other, the distance between the second lens 312 and the reverse total internal reflection prism assembly 32 is relatively large, but this will result in a longer length of the entire lighting device 30 along the direction of the first optical axis 40, thereby increasing the volume of the lighting device 30. In the embodiment of the present application, the second lens 312 is arranged obliquely, which can avoid the interference of the light beam between the second lens 312 and the reverse total internal reflection prism assembly 32, and at the same time shorten the length of the lighting device 30 along the direction of the first optical axis 40, thereby reducing the volume of the lighting device 30. The specific inclination angle of the second lens 312 is not limited in the embodiment of the present application.

[0057] The first lens 311 is close to the laser emitter and the light beam is relatively divergent. Therefore, the first lens 311 converges the light beam, reduces the spot size of the light beam and collimates the light beam. After receiving the light beam converged by the first lens 311, the third lens 313 further converges the light beam and reduces the spot size of the light beam. The second lens 312 can balance the field optical path while shortening the length of the lighting device 30 along the direction of the first optical axis 40.

[0058] Optionally, the effective focal length of the first lens 311 is F1, the effective focal length of the third lens 313 is F2, and the effective focal length of the second lens 312 is F3;

[0059] F1 satisfies the formula 0.1 < |F1 / F| < 0.5;

[0060] F2 satisfies the formula 0.8 < |F2 / F| < 1.6;

[0061] F3 satisfies the formula 0.3 < |F3 / F| < 0.8;

[0062] Where F is the effective focal length of the lighting device 30. The effective focal length is a measure of the convergence or divergence of light in an optical system, referring to the distance from the center of the lens to the focus where the light converges. In the embodiments of the present application, the focal lengths of the first lens 311, the second lens 312, and the third lens 313 satisfy the above formula. The effective focal length of the lens can be in other ranges, which is not limited in the embodiments of the present application.

[0063] Optionally, the lighting device 30 further includes a light homogenizing component 34, and the light homogenizing component 34 is located on the incident light side of the lens assembly 41. The light homogenizing component 34 can optimize the spot shape of the incident light beam and homogenize the light beam. Ultra-short throw projectors in the related art generally include ultra-short throw projectors with laser light sources and ultra-short throw projectors with LED light sources. The ultra-short throw projector with an LED light source can achieve miniaturization in volume, but the resolution of the ultra-short throw projector with an LED light source is mostly 720P. The ultra-short throw projector with a laser light source can improve the resolution and display brightness, so that the contrast of the picture of the laser ultra-short throw projector is better, the imaging is clearer, the colors are more vivid, and the brightness is higher. Due to the characteristics of the laser beam in the laser ultra-short throw projector, such as differences in quality and easy deviation in directivity, in the lighting device, the light homogenizing component 34 is provided to receive the laser beam, and the laser beam is homogenized and the spot is optimized before entering the lens assembly after passing through the light homogenizing component 34.

[0064] Optionally, the light homogenizing component 34 includes a light guide tube 341. The light guide tube 341 is a transparent glass tube. The incident light port and the outgoing light port of the light guide tube 341 are rectangles with the same shape and area. The laser beam enters the lighting device from the incident light port of the light guide tube 341 and then shoots towards the lens assembly 31 from the outgoing light port of the light guide tube 341, and the light beam is homogenized and the spot is optimized during the process of passing through the light guide tube 341.

[0065] In addition, the light homogenizing component 34 can also include a fly-eye lens. The fly-eye lens is usually formed by combining a series of small lenses. Two columns of fly-eye lens arrays are arranged in parallel to divide the spot of the input laser beam, and the divided spots are accumulated through the subsequent focusing lens, so as to achieve the homogenization of the light beam and the optimization of the spot. In a lighting device, the light homogenizing component 34 can select the light guide tube 341 or the fly-eye lens, which is not limited in the embodiments of the present application.

[0066] In summary, the embodiment of the present application provides an illumination device, including a lens assembly, a reverse total internal reflection prism assembly, and a light valve arranged in sequence along the optical path direction of the illumination device. The lens assembly includes a first lens and a second lens arranged in sequence along the optical path direction. The reverse total internal reflection prism assembly includes a reverse total internal reflection prism and a compensation prism located on the incident light surface of the reverse total internal reflection prism. After the first lens receives the light beam, it guides the light beam to the second lens. The second lens guides the received light beam to the compensation prism. After the light beam passing through the compensation prism reduces the spot size, it is output to the light valve through the reverse total internal reflection prism. The light valve reflects the light beam towards the reverse total internal reflection prism, and the reverse total internal reflection prism guides the light beam to the lens. The compensation prism refracts the light beam while reducing the spot size, so that the light receiving area of the reverse total internal reflection prism can be reduced, thereby reducing the size of the reverse total internal reflection prism and decreasing the length of the illumination device along the direction of the system optical axis. Moreover, the lens assembly, the reverse total internal reflection prism assembly, and the light valve are arranged in sequence along the direction of the system optical axis, without setting a reflector, reducing the volume of the illumination device. This solves the problem of the large volume of the illumination device in the related art and achieves the effect of reducing the volume of the illumination device.

[0067] As Figure 8 shown, it is a schematic structural diagram of a laser projection device provided by an embodiment of the present application. The laser projection device 60 includes the illumination device 30 in any of the above embodiments, a projection lens 50, and other light source components, heat dissipation components, etc. The light beam emitted by the blue laser 61 passes through a telescope system and a fly-eye lens, and then is incident on a dichroic mirror 62 first. The dichroic mirror 62 guides the laser to the lens assembly 63, and passes through the lens assembly 63 and enters the fluorescent wheel 64. The fluorescent wheel 64 reflects the fluorescence and then is incident on the lens assembly 63 again. After being converged by the lens assembly 63, it is incident on the dichroic mirror 62. The dichroic mirror 62 transmits the light beam and guides the light beam to a reflector adjacent to the dichroic mirror 62. After reflection, it is transmitted through the dichroic mirror 62 again, and passes through a converging lens and enters the light homogenizing component in the illumination device 30.

[0068] In the related art, as Figure 2 shown, a reflector is provided in the illumination device. To enable the light valve to completely receive the light emitted by the light homogenizing component, the overall optical path in the illumination device is inclined. After the light homogenizing component and the light valve are placed obliquely, other components such as the light source component and the heat dissipation component in the laser projection device that match the illumination device are also placed obliquely, resulting in a large volume of the entire laser projection device. When the laser projection device is a desktop ultra-short-throw laser projection device, one of its advantages is a small volume. The ultra-short-throw projector with an LED light source can achieve a small volume, but the resolution of the ultra-short-throw projector with an LED light source is mostly 720P, and it cannot achieve a high-resolution effect. In summary, it means that the desktop ultra-short-throw laser projection device in the related art cannot have both high resolution and small device volume.

[0069] The laser projection device 60 provided by the embodiment of the present application includes the lighting device 30 in any of the above embodiments. The first lens in the lens assembly of the lighting device is vertically arranged along the first optical axis direction, converging the light beam, reducing the spot size of the light beam and collimating the light beam. The third lens is vertically arranged along the first optical axis direction, which can further converge the light beam and reduce the spot size of the light beam. The second lens is obliquely arranged along the first optical axis direction, which can avoid interference with the reverse total internal reflection prism assembly, and at the same time can balance the optical path of each field of view, shorten the lens pitch in the lens assembly of the lighting device and the distance between the lens assembly and the reverse total internal reflection prism assembly, so as to shorten the length of the lighting device along the optical axis direction of the system. And the light homogenizing component of the lighting device 30 and the light valve in the present application can be arranged in parallel along the optical axis system direction, reducing the volume of the lighting device 30. Other light source components, heat dissipation components, etc. in the entire laser projection device 60 that are matched with the lighting device 30 can be placed vertically or horizontally along with the lighting device 30, thereby reducing the volume of the entire laser projection device 60.

[0070] In addition, the laser projection device 60 in the embodiment of the present application includes a galvanometer, and the galvanometer can improve the resolution of the light valve, enabling the laser projection device 60 to reach a 1080P resolution. The laser projection device 60 in the embodiment of the present application further includes a reverse total internal reflection prism with a compensation prism assembled. The compensation prism can reduce the spot size of the incident light beam and refract the light beam, thereby reducing the area of the light beam received by the reverse total internal reflection prism, thereby reducing the size of the reverse total internal reflection prism, that is, reducing the back working distance of the lighting device. Due to the reduction in the size of the reverse total internal reflection prism, the light valve and the projection lens approach the reverse total internal reflection prism, reducing the overall length of the lighting device along the optical axis direction. At the same time, the shortening of the back working distance can relatively reduce the size of the projection lens 50, thereby obtaining a laser projection device 60 with a smaller volume.

[0071] Therefore, a laser projection device 60 including a lighting device 30 provided by the embodiment of the present application can be reduced in both the length and thickness directions of the projection device, thereby reducing the device volume, and at the same time can achieve a relatively high resolution.

[0072] In summary, the embodiment of the present application provides a laser projection device, including an illumination device, a lens assembly, a reverse total internal reflection prism assembly, and a light valve sequentially arranged along the optical path direction of the illumination device. The lens assembly includes a first lens and a second lens sequentially arranged along the optical path direction. The reverse total internal reflection prism assembly includes a reverse total internal reflection prism and a compensation prism located on the incident light surface of the reverse total internal reflection prism. After the first lens receives the light beam, it guides the light beam to the second lens. The second lens guides the received light beam to the compensation prism. After the light beam passing through the compensation prism reduces the spot size, it is output to the light valve through the reverse total internal reflection prism. The light valve reflects the light beam towards the reverse total internal reflection prism, and the reverse total internal reflection prism guides the light beam to the lens. The compensation prism reduces the spot size and refracts the light beam at the same time, so that the light receiving area of the reverse total internal reflection prism can be reduced, thereby reducing the size of the reverse total internal reflection prism and decreasing the length of the illumination device along the direction of the system optical axis. Moreover, the lens assembly, the reverse total internal reflection prism assembly, and the light valve are sequentially arranged along the direction of the system optical axis, and there is no need to set a reflector, reducing the volume of the illumination device. It solves the problem that the volume of the illumination device in the related art is relatively large, and achieves the effect of reducing the volume of the illumination device.

[0073] The foregoing are only optional embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A lighting device, characterized in that, The lighting device includes a lens assembly, a reverse total internal reflection prism assembly, a light valve, and a galvanometer mirror arranged in sequence along the optical path direction of the lighting device; The lens assembly includes a first lens and a second lens arranged in sequence along the optical path direction. After receiving the light beam, the first lens guides the light beam to the second lens. The second lens guides the received light beam to the reverse total internal reflection prism assembly and outputs it to the light valve through the reverse total internal reflection prism assembly. The light valve outputs the received light beam to the lens; The reverse total internal reflection prism assembly includes a reverse total internal reflection prism and a compensation prism located on the incident light surface of the reverse total internal reflection prism. The compensation prism is used to reduce the spot size of the incident light beam; The galvanometer mirror is located between the reverse total internal reflection prism assembly and the light valve. The light beam guided by the reverse total internal reflection prism assembly to the light valve passes through the galvanometer mirror and then shoots towards the light valve. The light valve guides the received light beam to the galvanometer mirror. The galvanometer mirror processes the light beam emitted by the light valve and then guides it to the reverse total internal reflection prism, and is guided to the lens through the reverse total internal reflection prism; 2. The lighting device according to claim 1, characterized in that, The reverse total internal reflection prism is a triangular prism, and the incident light surface of the reverse total internal reflection prism is the bottom surface; The compensation prism is a triangular prism, and the bottom surface of the compensation prism is attached to the bottom surface of the reverse total internal reflection prism; 3. The lighting device according to claim 1, characterized in that, The lens assembly further includes a third lens, and the first lens, the third lens, and the second lens are arranged in sequence along the optical path direction; 4. The lighting device according to claim 3, characterized in that, The optical axis of the first lens is parallel to the first optical axis of the light beam incident on the first lens. The optical axis of the third lens is parallel to the first optical axis. The optical axis of the second lens has a first included angle with the first optical axis, and the included angle between the optical axis of the second lens and the incident light surface of the reverse total internal reflection prism is greater than the included angle between the optical axis of the third lens and the incident light surface of the reverse total internal reflection prism; Among them, the first lens is used to reduce the spot size of the light beam and collimate the light beam. The third lens is used to reduce the spot size of the light beam. The second lens is used to balance the field light path; 5. The lighting device according to claim 1, characterized in that, The reverse total internal reflection prism includes a space enclosed by a first side surface, a bottom surface, and a second side surface. The second lens guides the light beam to the bottom surface and injects it into the total internal reflection prism. The light beam passes through the first side surface and exits the total internal reflection prism. The light beam exiting from the first side surface is reflected by the light valve and then enters the bottom surface of the total internal reflection prism from the first side surface. After being reflected by the bottom surface, it shoots towards the second side surface and passes through the second side surface and shoots towards the lens; The compensation prism is located on the bottom surface of the total internal reflection prism, and the compensation prism is used to compensate the field light path; 6. The lighting device according to claim 3, characterized in that, The effective focal length of the first lens is F1, the effective focal length of the third lens is F2, and the effective focal length of the second lens is F3; F1 satisfies the formula 0.1 < |F1 / F| < 0.5; F2 satisfies the formula 0.8 < |F2 / F| < 1.6; F3 satisfies the formula 0.3 < |F3 / F| < 0.8; Where F is the effective focal length of the lighting device.

7. The lighting device according to claim 1, characterized in that, The lighting device further includes a light homogenizing component, and the light homogenizing component is located on the light incident side of the lens component.

8. The lighting device according to claim 7, characterized in that, The light homogenizing component includes a light guide pipe.

9. A laser projection device, characterized in that, A lighting device according to any one of claims 1-8 is included.

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