Projection device and projection system

Abstract

The application discloses a projection device and a projection system, the projection device comprises: at least two laser light sources for emitting laser beams of the same color; at least one beam-reducing element located on the light-emitting side of the at least one laser light source, the beam-reducing element comprises an entrance surface and an exit surface, the entrance surface and the exit surface are parallel and have a set thickness, and the entrance surface of the beam-reducing element is arranged at a set angle with the emitted light beam of the corresponding laser light source; and the beam-reducing element is used for refracting the emitted light beam of the corresponding laser light source at least twice, so that the emitted light beam of the corresponding laser light source moves towards the direction of the emitted light beam of the other laser light source, thereby achieving a beam-reducing effect, the structure of the beam-reducing element is simple, the emitted light beam of the adjacent laser light source can be avoided from being shielded, and the compact arrangement of the laser light sources is facilitated.

Description

Technical Field

[0001] This invention relates to the field of projection display technology, and more particularly to a projection device and projection system. Background Technology

[0002] Laser light sources are increasingly widely used in projection devices due to their advantages of high brightness, high contrast, and wide color gamut. As the demand for projected image brightness increases, the number of laser light sources required in projection devices also increases accordingly. To achieve miniaturization of projection devices, a compact arrangement of laser light sources is usually adopted. However, this arrangement results in a relatively large light spot, necessitating beam reduction to decrease the size of subsequent optical components.

[0003] Current beam-shrinking solutions typically involve setting up double mirrors on the light-emitting side of each laser source to fold the optical path. However, the double mirror solution has requirements on the area and spacing of the mirrors. When the spacing between the laser sources is small, it is easy to block the emitted light of adjacent laser sources, which is not conducive to the miniaturization of projection devices. Summary of the Invention

[0004] The present invention provides a projection device and projection system for achieving beam reduction when multiple monochromatic laser light sources are arranged in a compact manner.

[0005] The first aspect of the present invention provides a projection device, comprising: at least two laser light sources for emitting lasers of the same color;

[0006] At least one beam-shrinking element is located on the light-emitting side of at least one of the laser light sources. The beam-shrinking element includes an incident surface and an emitting surface, the incident surface and the emitting surface are parallel, and there is a predetermined thickness between the incident surface and the emitting surface. The incident surface of the beam-shrinking element is set at a predetermined angle with the emitted beam of the corresponding laser light source. The beam-shrinking element is used to refract the emitted beam of the corresponding laser light source at least twice, so that the emitted beam of the corresponding laser light source moves in a direction closer to the emitted beams of other laser light sources.

[0007] In some embodiments of the present invention, the beam-shrinking element is a parallel plate; the incident surface receives the emitted beam of the corresponding laser source and refracts the light towards the emitted surface, and the emitted surface refracts the incident light out.

[0008] In some embodiments of the present invention, an antireflection film is provided on the light-incident surface and / or the light-exit surface.

[0009] In some embodiments of the present application, the beam-reducing element is a parallel flat plate; the light-in surface and the light-out surface each comprise a first region and a second region, the first region of the light-in surface and the first region of the light-out surface are arranged in a staggered manner, the second region of the light-in surface is arranged opposite to the first region of the light-out surface, and the second region of the light-out surface is arranged opposite to the second region of the light-in surface; the first region of the light-out surface is provided with a first anti-reflection film, and the first region of the light-in surface is provided with a second anti-reflection film.

[0010] The second region of the light-in surface receives the light beam emitted by the corresponding laser light source and refracts the light beam towards the first anti-reflection film, and the light beam is incident on the second region of the light-out surface after being reflected between the first anti-reflection film and the second anti-reflection film at least twice, and is refracted out by the second region of the light-out surface.

[0011] In some embodiments of the present application, the second region of the light-in surface and / or the second region of the light-out surface is provided with an anti-reflection film.

[0012] In some embodiments of the present application, the projection device comprises two laser light sources and two beam-reducing elements, the two laser light sources are a first laser light source and a second laser light source, and the two beam-reducing elements are a first beam-reducing element and a second beam-reducing element.

[0013] The first beam-reducing element is located on the light-emitting side of the first laser light source, and the second beam-reducing element is located on the light-emitting side of the second laser light source.

[0014] The light beam emitted by the first laser light source moves towards the direction of the light beam emitted by the second laser light source after passing through the first beam-reducing element, and the light beam emitted by the second laser light source moves towards the direction of the light beam emitted by the first laser light source after passing through the second beam-reducing element.

[0015] In some embodiments of the present application, the projection device comprises three laser light sources and two beam-reducing elements, the three laser light sources are a first laser light source, a second laser light source and a third laser light source, and the two beam-reducing elements are a first beam-reducing element and a second beam-reducing element.

[0016] The third laser light source is located between the first laser light source and the second laser light source; the first beam-reducing element is located on the light-emitting side of the first laser light source, and the second beam-reducing element is located on the light-emitting side of the second laser light source.

[0017] The light beam emitted by the first laser light source moves towards the direction of the light beam emitted by the third laser light source after passing through the first beam-reducing element, and the light beam emitted by the second laser light source moves towards the direction of the light beam emitted by the third laser light source after passing through the second beam-reducing element.

[0018] In some embodiments of the present application, the projection device further comprises:

[0019] a wavelength conversion element located on the side of each beam-reducing element away from each laser light source, for emitting light beams of other wavelengths under the excitation of the light beams emitted by the laser light sources;

[0020] a converging lens located between each beam-reducing element and the wavelength conversion element.

[0021] In some embodiments of the present application, the projection device further comprises:

[0022] an illumination system located on the light-emitting side of the wavelength conversion element, for shaping and homogenizing the incident light beams;

[0023] a projection lens located on the light-emitting side of the illumination system, for projecting an image.

[0024] In another aspect of the present application, a projection system is provided, comprising any of the above projection devices and a projection screen located on the light-emitting side of the projection device.

[0025] The present application has the following advantages:

[0026] The present application provides a projection device and a projection system. The projection device comprises: at least two laser light sources for emitting laser beams of the same color; and at least one beam-reducing element located on the light-emitting side of the at least one laser light source. The beam-reducing element comprises an incident surface and an emitting surface, which are parallel and have a set thickness. The incident surface of the beam-reducing element is arranged at a set angle with the emitted light beams of the corresponding laser light source. The beam-reducing element is used to refract the emitted light beams of the corresponding laser light source at least twice, so as to move the emitted light beams of the corresponding laser light source towards the direction of the emitted light beams of other laser light sources, thereby achieving a beam-reducing effect. The structure of the beam-reducing element is simple, and the emitted light beams of adjacent laser light sources can be avoided from being blocked, which is conducive to the compact arrangement of the laser light sources. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiments of the present application will be briefly introduced as follows. Obviously, the drawings introduced below are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0028] Figure 1 FIG. 1 is a structural schematic diagram of a projection device in the related art;

[0029] Figure 2 FIG. 2 is another structural schematic diagram of a projection device in the related art;

[0030] Figure 3 Structure diagram of a shrinking element according to an embodiment of the present application;

[0031] Figure 4 Structure diagram of a projection device according to an embodiment of the present application;

[0032] Figure 5 Optical path diagram in a shrinking element according to an embodiment of the present application;

[0033] Figure 6 Structure diagram of a shrinking element according to an embodiment of the present application;

[0034] Figure 7 Structure diagram of a projection device according to an embodiment of the present application;

[0035] Figure 8 Optical path diagram in a shrinking element according to an embodiment of the present application;

[0036] Figure 9 Structure diagram of a projection device according to an embodiment of the present application;

[0037] Figure 10 Structure diagram of a projection device according to an embodiment of the present application. DETAILED DESCRIPTION

[0038] In order to make the above objectives, features and advantages of the present application more clear and comprehensible, the present application will be further described below with reference to the accompanying drawings and embodiments. However, the example embodiments can be implemented in various forms, and should not be understood as being limited to the embodiments set forth herein; on the contrary, these embodiments are provided to make the present application more comprehensive and complete, and to fully convey the ideas of the example embodiments to those skilled in the art. The same reference numerals in the drawings represent the same or similar structures, and thus repeated description thereof will be omitted. The expressions of position and direction described in the present application are explained with reference to the drawings, but can be changed as needed, and the changes made are included in the protection scope of the present application. The drawings of the present application are only used to illustrate the relative positional relationship and do not represent the true proportions.

[0039] The laser projection device can include a light source device, an illumination system and a projection lens, wherein the light source device can include a monochromatic laser light source or a multi-color laser light source. To achieve full-color display, a fluorescent color wheel is usually arranged on the light exit side of the laser light source when a monochromatic laser light source is used, and the monochromatic laser light is converted into other colors of light after being incident on the fluorescent color wheel.

[0040] The brightness of the light emitted by a projection device determines the display quality of the projected image. As the demand for projected image brightness increases, the number of laser light sources required in the projection device also needs to increase accordingly. In order to balance display brightness and miniaturization of the projection device, a compact arrangement of monochromatic laser light sources is usually adopted. This arrangement results in a larger combined light spot and requires a larger volume of the lenses through which the beam passes in the projection device. Therefore, it is necessary to reduce the beam emitted by the monochromatic laser light source.

[0041] In related technologies, beam contraction is usually achieved by setting up two reflectors on the light-emitting side of a single laser source. The following explanation will take the case where the light source device includes two monochromatic laser sources as an example.

[0042] Figure 1 This is one of the structural schematic diagrams of projection devices in related technologies.

[0043] like Figure 1 As shown, the light source device may include a first laser light source 11, a second laser light source 12, a first reflector 21 and a second reflector 22, wherein the first laser light source 11 and the second laser light source 12 are arranged side by side, and the first reflector 21 and the second reflector 22 are both arranged on the light-emitting side of the first laser light source 11. The projection device also includes a converging lens 30, a fluorescent color wheel 40 and an illumination system 50, etc.

[0044] The laser beam emitted from the first laser source 11 is incident on the first reflector 21, reflected by the first reflector 21 to the second reflector 22, and then reflected to the converging lens 30. The laser beam emitted from the second laser source 12 is directly incident on the converging lens 30. Furthermore, the beam emitted from the second reflector 22 moves closer to one side of the beam emitted from the second laser source 12, and the beam emitted from the second reflector 22 is parallel to the beam emitted from the second laser source 12, thereby achieving a beam-shortening effect. After both beams are incident on the converging lens 30, they are further shortened and then incident on the fluorescent color wheel 40, where they excite other colors of light. Subsequently, the beams are incident on the lighting system 50.

[0045] However, the scheme of using multiple mirrors to reflect the light beam multiple times requires a large number of components, and correspondingly, it requires more mechanical structural parts. In actual installation, the requirements for size and tolerance are more stringent.

[0046] Figure 2 This is the second schematic diagram of the structure of a projection device in related technologies.

[0047] like Figure 2As shown, the second reflector 22 in the related art needs to be arranged between the outgoing light beams of the first laser light source 11 and the second laser light source 12. Since the reflector needs to ensure that it has a certain size of the reflecting area so that it can completely reflect the light beams emitted by the laser light sources, when the interval between the first laser light source 11 and the second laser light source 12 is small, the second reflector 22 may block the outgoing light beams of the second laser light source 12, resulting in loss of light and affecting the light combining quality.

[0048] Therefore, the embodiment of the present application provides a projection device, which can include at least two laser light sources and at least one beam shrinking element in the light source device.

[0049] In the embodiment of the present application, the beam shrinking element performs beam shrinking and light combining on the monochromatic laser beams. The laser light source can be a monochromatic laser, can be an out-light region of the same color laser in the same laser, or can be an out-light region of the same color in different lasers. The specific type of the laser light source is not limited herein.

[0050] Figure 3 A structure diagram of the beam shrinking element provided by the embodiment of the present application is shown.

[0051] As shown in the structure diagram of the projection device provided by the embodiment of the present application, Figure 3 The beam shrinking element 60 includes an incident surface I and an outgoing surface O. The incident surface I and the outgoing surface O of the beam shrinking element are parallel and have a set thickness therebetween. In the specific implementation, the beam shrinking element can be a parallel flat plate made of glass. In the projection device, the incident surface I of the beam shrinking element is arranged at a set angle with the outgoing light beam of the corresponding laser light source, so as to refract the outgoing light beam of the corresponding laser light source at least twice, and move the outgoing light beam of the corresponding laser light source to the direction close to the outgoing light beam of the other laser light source.

[0052] In the specific implementation, in order to achieve better light combining effect, the laser light sources can be arranged side by side, so that the outgoing light directions of the laser light sources are the same. The beam shrinking element is correspondingly arranged on the light emitting side of the laser light source, so that the outgoing light beam of the laser light source can be translated to the direction close to the outgoing light beam of the other laser light source to ensure the light combining effect. The following embodiments are described taking this case as an example.

[0053] In the specific implementation, the incident surface I and / or the outgoing surface O of the beam shrinking element 60 can also be provided with an anti-reflection film T, so as to increase the transmittance of the light and improve the brightness of the projection image.

[0054] Figure 4 A structure diagram of the projection device provided by the embodiment of the present application is shown.

[0055] As shown in the structure diagram of the projection device provided by the embodiment of the present application,Figure 4 As shown, two laser light sources and one beam-reducing element can be included in the projection device, which are referred to as a first laser light source 11, a second laser light source 12 and a beam-reducing element 60 for the convenience of description. The first laser light source 11 and the second laser light source 12 are arranged side by side, and the two emit laser beams of the same color. The beam-reducing element 60 can be arranged on the light exit side of the first laser light source 11 or the second laser light source 12. The laser beams emitted by the laser light sources are incident on the corresponding beam-reducing element, and after being refracted twice, the laser beams are incident on the subsequent optical components. The embodiment of the present application takes the case where the beam-reducing element 60 is arranged on the light exit side of the first laser light source 11 as an example for description.

[0056] Figure 5 One of the light paths in the beam-reducing element provided by the embodiment of the present application is shown in the figure.

[0057] Referring to Figure 4 and Figure 5 , the light entrance surface I of the beam-reducing element 60 is arranged at a certain angle with respect to the light beam L1 emitted by the first laser light source 11, which is referred to as ∠1. The angle ∠2 at which the light beam L1 is incident on the light entrance surface I of the beam-reducing element 60 satisfies ∠1+∠2=90°. The light beam L1 is refracted for the first time at the light entrance surface I of the beam-reducing element 60. According to the refraction law, the following equation can be obtained:

[0058] n1sin∠2=n2sin∠3;

[0059] wherein n1 represents the refractive index of air, n2 represents the refractive index of the material used by the parallel plate, and ∠3 represents the refraction angle of the light beam L1 after being incident on the light entrance surface I of the beam-reducing element 60.

[0060] Since the refractive index of the material used by the beam-reducing element is greater than that of air, ∠3<∠2. The propagation direction of the light beam L1 inside the beam-reducing element 60 deviates from the original propagation direction and is deflected towards the side close to the normal. After propagating a certain distance inside the beam-reducing element 60, the light beam L1 is refracted for the second time at the light exit surface O of the beam-reducing element 60 and is then emitted. Since the light entrance surface I and the light exit surface O are parallel, the emitted light beam is parallel to the light beam incident on the beam-reducing element 60 and is translated a certain distance towards the side of the second laser light source 12. According to the basic principle of geometric optics, the distance by which the light beam L1 emitted by the first laser light source 11 is translated towards the side of the second laser light source 12 after passing through the beam-reducing element 60 is:

[0061] d×(sin(∠2-∠3)) / cos∠3

[0062] wherein d represents the thickness between the light entrance surface I and the light exit surface O of the beam-reducing element 60.

[0063] In the embodiment of the present application, the parallel plate is arranged on the light emitting side of one of the laser light sources of the projection device as the beam narrowing element, so that the beam narrowing effect is achieved, the structure is simple, the number of mechanical components required is small, and the light beams of the adjacent laser light sources are not blocked, which is beneficial to the compact arrangement of the laser light sources.

[0064] Figure 6 The second structural diagram of the beam narrowing element is provided for the embodiment of the present application.

[0065] As Figure 6 shown, the beam narrowing element 60 can adopt a parallel plate, the light incident surface I and the light emitting surface O of the beam narrowing element 60 each include a first region and a second region, wherein the first region of the light incident surface I and the first region of the light emitting surface O are arranged in a staggered manner, the second region of the light incident surface I and the first region of the light emitting surface O are arranged in a facing manner, and the second region of the light emitting surface O is arranged in a facing manner with the second region of the light incident surface I.

[0066] The first anti-reflection film R1 is arranged on the first region of the light emitting surface O, the second anti-reflection film R2 is arranged on the first region of the light incident surface I, and the second region of the light incident surface I and / or the second region of the light emitting surface O can be provided with a transparent film T to increase the brightness of the light beams.

[0067] In the specific implementation, the areas of the first region and the second region in the light incident surface I and the light emitting surface O of the beam narrowing element 60 and the areas of the first anti-reflection film R1 and the second anti-reflection film R2 can be determined according to the distance between the laser light sources and the divergence degree of the light beams emitted by the laser light sources.

[0068] Figure 7 The second structural diagram of the projection device is provided for the embodiment of the present application.

[0069] As Figure 7 shown, the beam narrowing element 60 is arranged on the light emitting side of the first laser light source 11, by adjusting the ranges covered by the first region and the second region in the light incident surface I and the light emitting surface O of the beam narrowing element 60, the second region of the light incident surface I can receive the light beams emitted by the first laser light source 11 and refract the light beams to the first anti-reflection film R1, and then the light beams can be reflected at least twice between the first anti-reflection film R1 and the second anti-reflection film R2 to be incident to the second region of the light emitting surface O, and then the light beams are refracted by the second region of the light emitting surface O to be emitted.

[0070] Figure 8 The second light path diagram in the beam narrowing element is provided for the embodiment of the present application.

[0071] Referring to Figure 7 and Figure 8, the incident surface I of the beam-reducing element 60 is arranged at an angle with the exit light beam L2 of the first laser light source 11, which is referred to as the angle ∠4, then the incident angle ∠5 of the light beam L2 incident to the incident surface I of the beam-reducing element 60 satisfies ∠4+∠5=90°, the light beam L2 is refracted for the first time at the second region of the incident surface I of the beam-reducing element 60, and according to the refraction law, it can be obtained that:

[0072] n1sin∠5=n2sin∠6;

[0073] wherein n1 represents the refractive index of air, n2 represents the refractive index of the material adopted by the parallel plate, and ∠6 represents the refraction angle of the light beam L2 after being incident to the incident surface I of the beam-reducing element 60.

[0074] Since the refractive index of the material adopted by the beam-reducing element is greater than that of air, ∠6<∠5, the propagation direction of the light beam L2 inside the beam-reducing element 60 deviates from the original propagation direction and is deflected to the side close to the normal, then the light beam L2 is incident to the first reflection-increasing film R1, is reflected to the second reflection-increasing film R2 by the first reflection-increasing film R1, is reflected to the second region of the exit surface O by the second reflection-increasing film R2, and is emitted after being refracted for the second time, since the light beam can be reflected at least twice between the first reflection-increasing film R1 and the second reflection-increasing film R2, the light beam as a whole produces a translation, according to the basic principle of geometric optics, the distance of the translation of the light beam L2 emitted by the first laser light source 11 to the side of the second laser light source 12 after passing through the beam-reducing element 60 is at least:

[0075] 2dxtan(∠6)xsin(∠4)

[0076] wherein d represents the thickness between the incident surface I and the exit surface O of the beam-reducing element 60.

[0077] The reflection films arranged on the incident surface and the exit surface of the beam-reducing element can make the light beam incident thereto be reflected multiple times between the reflection films, so that the distance of the translation of the light beam between adjacent laser light sources can be greater, and meanwhile, it is beneficial to reduce the thickness of the beam-reducing element and reduce the loss of light.

[0078] Figure 9 Structure schematic diagram three of the projection device provided by the embodiment of the present application.

[0079] As shown in Figure 9 , the projection device can include two laser light sources and two beam-reducing elements, the two laser light sources are a first laser light source 11 and a second laser light source 12, and the two beam-reducing elements are a first beam-reducing element 61 and a second beam-reducing element 62.

[0080] The first laser light source 11 and the second laser light source 12 are arranged side by side, the light emitting directions of the first laser light source 11 and the second laser light source 12 are the same, the first beam shrinking element 61 is located on the light emitting side of the first laser light source 11, the second beam shrinking element 62 is located on the light emitting side of the second laser light source 12, and the light beam emitted by the first laser light source 11 is translated to the direction of the light beam emitted by the second laser light source 12 after passing through the first beam shrinking element 61, and the light beam emitted by the second laser light source 12 is translated to the direction of the light beam emitted by the first laser light source 11 after passing through the second beam shrinking element 62.

[0081] In the embodiment of the application, the first beam shrinking element 61 and the second beam shrinking element 62 can adopt any one of the beam shrinking elements shown in Figs. Figure 3 and Figure 6 The beam shrinking elements correspond to the two laser light sources respectively, and the light beams emitted by the laser light sources can be shrunk to a greater extent, and the spot area is reduced.

[0082] Figure 10 Fig. 4 is a structural schematic diagram of a projection device provided by the embodiment of the application.

[0083] As shown in Fig. Figure 10 , the projection device can include three laser light sources and two beam shrinking elements, and the three laser light sources are a first laser light source 11, a second laser light source 12 and a third laser light source 13, and the two beam shrinking elements are a first beam shrinking element 61 and a second beam shrinking element 62.

[0084] The first laser light source 11 and the second laser light source 12 are arranged side by side, the third laser light source 13 is located between the first laser light source 11 and the second laser light source 12, the third laser light source 13 can be arranged side by side with the first laser light source 11 and the second laser light source 12, or can not be arranged side by side with the first laser light source 11 and the second laser light source 12, the distance between the third laser light source 13 and the first laser light source 11 and the distance between the third laser light source 13 and the second laser light source 12 can be the same or different, which is not limited herein, but the light emitting directions of the first laser light source 11, the second laser light source 12 and the third laser light source 13 remain the same. The first beam shrinking element 61 is located on the light emitting side of the first laser light source 11, the second beam shrinking element 62 is located on the light emitting side of the second laser light source 12, the light beam emitted by the first laser light source 11 is translated to the direction of the light beam emitted by the third laser light source 13 after passing through the first beam shrinking element 61, and the light beam emitted by the second laser light source 12 is translated to the direction of the light beam emitted by the third laser light source 13 after passing through the second beam shrinking element 62.

[0085] In the embodiment of the application, the first beam shrinking element 61 and the second beam shrinking element 62 can adopt any one of the beam shrinking elements shown in Figs. Figure 3 and Figure 6Any one of the illustrated beam-reducing elements, without being limited, two beam-reducing elements are arranged for the three laser light sources to realize beam reduction, which is conducive to simplifying the structure of the projection device and realizing miniaturization.

[0086] In a specific implementation, the number of laser light sources and beam-reducing elements in the projection device can be set according to requirements, and the above embodiments only exemplify several possible implementation manners and are not used to limit the number of laser light sources and beam-reducing elements.

[0087] With reference to Figure 3 , Figure 7 , Figure 9 and Figure 10 , the projection device can further include a converging lens 30, a wavelength conversion element 41, an illumination system 50, and a projection lens 70.

[0088] The wavelength conversion element 41 is located on the side of each beam-reducing element away from each laser light source, and the wavelength conversion element 41 can emit light beams of other wavelengths under the excitation of light beams emitted by each laser light source, thereby realizing full-color projection display. In a specific implementation, the wavelength conversion element 41 can be a fluorescent color wheel.

[0089] The converging lens 30 is located between each beam-reducing element and the wavelength conversion element 41, and can further reduce the light beams emitted by each beam-reducing element, which is conducive to reducing the size of subsequent optical components.

[0090] The illumination system 50 is located on the light-emitting side of the wavelength conversion element 41, and is used to shape and homogenize incident light beams. The illumination system 50 can include light homogenizing components such as light pipes, compound eye lenses, and the like, and can also include some lens combinations and light modulation components, etc. The specific structure of the illumination system 50 is set according to specific use requirements, and is not limited herein.

[0091] The projection lens 70 is located on the light-emitting side of the illumination system 50, and is usually a combination of multiple lenses, which can be used for projection imaging. The specific structure of the projection lens 70 can be obtained according to optical design, and is not limited herein.

[0092] The embodiment of the present application further provides a projection system, which includes any one of the projection devices in the above embodiments and a projection screen located on the light-emitting side of the projection device. Since the beam-reducing elements are arranged in the projection device, more laser light sources can be arranged compactly in the projection device, the brightness of the light emitted by the projection device is improved, and the brightness of the projection display image is further improved, thereby improving the display quality.

[0093] According to the first inventive concept, the light-incident surface and the light-emitting surface of the beam-reducing element are parallel and have a set thickness therebetween, and the light-incident surface of the beam-reducing element is arranged at a set angle with the light-emitting beam of the corresponding laser light source, so that the light-emitting beam of the corresponding laser light source can be refracted at least twice, and the light-emitting beam of the corresponding laser light source is moved towards the light-emitting beam of the other laser light source, thereby achieving the beam-reducing effect.

[0094] According to the second inventive concept, a parallel plate is used as the beam-reducing element, and the beam-reducing effect can be achieved by arranging the beam-reducing element on the light-emitting side of only one of the laser light sources of the projection device, which is simple in structure, requires fewer mechanical components, and avoids blocking the light-emitting beam of the adjacent laser light source, thereby facilitating the compact arrangement of the laser light sources.

[0095] According to the third inventive concept, the antireflection film is arranged in a certain area of the light-incident surface and the light-emitting surface of the beam-reducing element, which can increase the light transmittance and improve the brightness of the projected image.

[0096] According to the fourth inventive concept, the reflective film is arranged in a certain area of the light-incident surface and the light-emitting surface of the beam-reducing element, which can cause the light beam incident thereinto to be reflected multiple times between the two reflective films, thereby increasing the distance of the light beam from the adjacent laser light source, and facilitating the reduction of the thickness of the beam-reducing element and the light loss.

[0097] According to the fifth inventive concept, the projection device includes two laser light sources and two beam-reducing elements, and the beam-reducing elements are arranged corresponding to the two laser light sources, respectively, which can more greatly reduce the light-emitting beam of the laser light source and reduce the spot area.

[0098] According to the sixth inventive concept, the projection device includes three laser light sources and two beam-reducing elements, and the two beam-reducing elements are arranged corresponding to the three laser light sources, respectively, which can achieve the beam-reducing effect, and facilitate the simplification and miniaturization of the structure of the projection device.

[0099] Although the preferred embodiments of the present application have been described, those skilled in the art can make further changes and modifications to the embodiments once they know the basic inventive concept. Therefore, the appended claims are intended to cover all changes and modifications falling within the scope of the present application.

[0100] Obviously, various modifications and changes can be made to the present application by those skilled in the art without departing from the spirit and scope of the present application. Thus, it is intended that the present application embrace all such modifications and changes and, accordingly, the appended claims are intended to cover all such modifications and changes as fall within the scope of the present application.

Claims

1. A projection device, characterized by The projection device comprises: at least two laser light sources for emitting laser beams of the same color; at least one beam-reducing element located on the light-emitting side of at least one of the laser light sources, the beam-reducing element comprising an incident surface and an emitting surface, the incident surface and the emitting surface being parallel, the incident surface and the emitting surface having a set thickness therebetween, the incident surface of the beam-reducing element being arranged at a set angle with the emitted beam of the corresponding laser light source; the beam-reducing element being configured to refract the emitted beam of the corresponding laser light source at least twice, so as to move the emitted beam of the corresponding laser light source towards the emitted beam of another laser light source; the beam-reducing element is a parallel flat plate; the incident surface and the emitting surface each comprise a first region and a second region, the first region of the incident surface and the first region of the emitting surface being arranged in a staggered manner, the second region of the incident surface being arranged opposite the first region of the emitting surface, and the second region of the emitting surface being arranged opposite the second region of the incident surface; the first region of the emitting surface is provided with a first anti-reflection film, and the first region of the incident surface is provided with a second anti-reflection film; the second region of the incident surface receives the emitted beam of the corresponding laser light source and refracts the beam towards the first anti-reflection film, the beam being reflected at least twice between the first anti-reflection film and the second anti-reflection film and then being incident on the second region of the emitting surface and being refracted by the second region of the emitting surface to be emitted.

2. The projection apparatus according to claim 1, wherein The second region of the incident surface and / or the second region of the emitting surface is / are provided with an anti-reflection film.

3. The projection apparatus according to claim 1 or 2, wherein, The projection device comprises two laser light sources and two beam-reducing elements, the two laser light sources being a first laser light source and a second laser light source, and the two beam-reducing elements being a first beam-reducing element and a second beam-reducing element; the first beam-reducing element is located on the light-emitting side of the first laser light source, and the second beam-reducing element is located on the light-emitting side of the second laser light source; the emitted beam of the first laser light source moves towards the emitted beam of the second laser light source after passing through the first beam-reducing element, and the emitted beam of the second laser light source moves towards the emitted beam of the first laser light source after passing through the second beam-reducing element.

4. The projection apparatus according to claim 1 or 2, wherein The projection device comprises three laser light sources and two beam-reducing elements, the three laser light sources being a first laser light source, a second laser light source, and a third laser light source, and the two beam-reducing elements being a first beam-reducing element and a second beam-reducing element; the third laser light source is located between the first laser light source and the second laser light source; the first beam-reducing element is located on the light-emitting side of the first laser light source, and the second beam-reducing element is located on the light-emitting side of the second laser light source; the emitted beam of the first laser light source moves towards the emitted beam of the third laser light source after passing through the first beam-reducing element, and the emitted beam of the second laser light source moves towards the emitted beam of the third laser light source after passing through the second beam-reducing element.

5. The projection apparatus according to claim 1 or 2, wherein Further comprising: a wavelength conversion element located on the side of each beam-reducing element away from each laser light source, configured to emit a light beam of another wavelength under the excitation of the emitted beam of the laser light source. A converging lens is located between each of the beam-reducing elements and the wavelength conversion element.

6. The projection apparatus according to claim 5, wherein, Further comprising: An illumination system is located on the light-exit side of the wavelength conversion element, for shaping and homogenizing the incident light beam; A projection lens is located on the light-exit side of the illumination system, for projecting the image.

7. A projection system, characterized by A projection screen is located on the light-exit side of the projection device.

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