CN113225544A

CN113225544A - Illumination system and projection apparatus

Info

Publication number: CN113225544A
Application number: CN202110534532.3A
Authority: CN
Inventors: 杜玉楠; 田勇
Original assignee: Qingdao Hisense Laser Display Co Ltd
Current assignee: Qingdao Hisense Laser Display Co Ltd
Priority date: 2021-05-17
Filing date: 2021-05-17
Publication date: 2021-08-06

Abstract

The application discloses lighting system and projection equipment belongs to laser technical field. The illuminating system comprises a digital micro-mirror device, a prism component, a light barrier and a projecting lens which are sequentially arranged along the light path direction of the illuminating system, wherein the light barrier comprises an opening area and a shielding area, the digital micro-mirror device processes and reflects received illuminating light beams and outputs the illuminating light beams, the imaging light beams output by the reflecting mirror of the digital micro-mirror device when in an open state are guided to the prism component, the imaging light beams can be emitted to the projecting lens through the prism component and the opening area of the light barrier, the shielding area of the light barrier can block non-imaging light beams output by the reflecting mirror of the digital micro-mirror device which cannot be blocked by the prism component when in a closed state from being emitted to the projecting lens, namely the light barrier can reduce the non-imaging light beams of the projecting lens, the projecting display image contrast can be improved, and the problem of poor quality of a projecting display image in the related technology is solved, the quality of the projection display picture is improved.

Description

Illumination system and projection apparatus

Technical Field

The application relates to the technical field of laser, in particular to an illumination system and laser projection equipment.

Background

The laser projection display technology is a novel projection display technology in the current market, and has the characteristics of clear imaging, bright color and higher brightness compared with an LED projection product, and the remarkable characteristics gradually enable the laser projection display technology to become a mainstream development direction in the market. The DMD includes a plurality of mirrors capable of rotating between two positions, which can be an open position and a closed position, and the light beam emitted from the DMD can be controlled by the rotating mirrors. The DMD is larger in size, the larger the pixel size is, the finer the display picture is, and the more the reflected light is, so that the brightness is higher.

An illumination system comprises a DMD and a prism, wherein the prism is required to enable an imaging light beam and a non-imaging light beam of the DMD to be completely incident on the prism so as to lead the imaging light beam out to a projection lens, and meanwhile, the non-imaging light beam is prevented from being incident to the projection lens.

The quality of the projection display picture of the illumination system is poor.

Disclosure of Invention

The embodiment of the application provides an illumination system and a projection device. The lighting system includes: the digital micromirror device, the prism component light barrier and the projection lens are sequentially arranged along the light path direction of the illumination system;

the prism assembly comprises a first light inlet surface and a first light outlet surface, the digital micromirror device is positioned outside the first light inlet surface, the light barrier is positioned outside the first light outlet surface, the digital micromirror device is used for processing the received light beams and guiding the processed light beams to the first light inlet surface of the prism assembly, the light barrier comprises an opening area and a shielding area, the size of the opening area is larger than or equal to the maximum size of a light spot of a plane where the light barrier is positioned when an imaging light beam output by a reflector in the digital micromirror device is in an open state, the imaging light beam can penetrate through the opening area to irradiate the projection lens, and the shielding area of the light barrier is used for blocking a non-imaging light beam output by the reflector in the digital micromirror device when the reflector is in a closed state from irradiating the projection lens.

Optionally, the prism assembly includes a first prism, the first prism is surrounded by the first light incident surface, the first light emitting surface, and the bottom surface, and the first light incident surface and the first light emitting surface are perpendicular to each other;

the non-imaging light beam comprises a first light beam which is emitted to the first light inlet surface of the prism assembly and is emitted through the bottom surface of the first prism and a second light beam which is emitted to the light inlet from the digital micromirror, and the shielding area of the light barrier comprises a first shielding area for shielding the first light beam and a second shielding area for shielding the second light beam.

Optionally, the first prism is configured to receive the imaging light beam through the first light incident surface, guide the imaging light beam to the bottom surface, reflect the imaging light beam to the first light emitting surface through the bottom surface to output the first prism, and a size of the first light incident surface is greater than or equal to a size of a light spot on a plane where the imaging light beam irradiates the bottom surface.

Optionally, the digital micromirror device is rectangular, and a short side of the digital micromirror device is parallel to the first light incident surface and perpendicular to the first light emitting surface.

Optionally, the first light incident surface satisfies a formula:

P≥2*L*tanθ+W_DMD；

wherein, P is the side length of the first light incident surface, and L is the distance from the mirror surface of the digital micromirror device to the first prism; theta is the numerical aperture angle, W, of the illumination system_DMDThe width of the short side of the digital micromirror device;

the numerical aperture angle of the illumination system satisfies the formula: θ ═ arcsin (1/2 × F); wherein F is the F number of the lighting system.

Optionally, the prism assembly further comprises a second prism and a flat glass, the second prism is enclosed by a second light incident surface, a second light emitting surface and a curved surface, the second light emitting surface is opposite to one surface of the flat glass, the bottom surface of the first prism is opposite to the other surface of the flat glass, the second light incident surface is used for receiving light beams and guiding the light beams to the curved surface, and the curved surface is used for reflecting the light beams to the second light emitting surface.

Optionally, the illumination system further comprises a galvanometer assembly located between the digital micromirror device and the prism assembly.

Optionally, the illumination system further includes a light uniformizing assembly and a light beam collimating and magnifying lens group, the light uniformizing assembly is configured to process the received light beam and guide the processed light beam to the light beam collimating and magnifying lens group, and the light beam collimating and magnifying lens group is configured to guide the light beam to the prism assembly.

Optionally, the light beam collimating and magnifying lens group includes a first lens, a second lens and a third lens which are sequentially arranged along the light path direction, the main optical axis of the first lens rotates a first included angle along the counterclockwise direction from the state parallel to the main optical axis of the dodging assembly, and the first included angle satisfies the formula:

θ₁<arcsin(2*L₁/D₁)；

wherein, theta₁Is the first angle, L₁The distance between the light outlet of the light homogenizing assembly and the axis of the first lens is; d₁Is the diameter of the first lens.

The projection device comprises the illumination system.

The beneficial effects brought by the technical scheme provided by the embodiment of the application at least comprise:

there is provided an illumination system comprising a digital micromirror device, a prism assembly, a light barrier, and a projection lens, wherein the light barrier comprises an opening region and a shielding region, the digital micromirror device processes the received light beam and then outputs the processed light beam in a reflection manner, and the imaging light beam output by the digital micro-mirror device when the reflector is in the open state is guided to the prism component and can be emitted to the projection lens through the prism component and the opening region of the light barrier, the shielding region of the light barrier can prevent the non-imaging light beam output by the digital micro-mirror device when the reflector of the digital micro-mirror device which is not blocked by the prism component is in the closed state from being emitted to the projection lens, the light barrier can reduce non-imaging light beams emitted to the projection lens, so that the contrast of a projection display picture can be improved, the problem of poor quality of the projection display picture in the related technology is solved, and the effect of improving the quality of the projection display picture is achieved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic diagram of an illumination system;

FIG. 2 is a schematic view of an alternative illumination system;

fig. 3 is a schematic structural diagram of an illumination system according to an embodiment of the present application;

FIG. 4 is a schematic structural diagram of a light barrier according to an embodiment of the present application;

FIG. 5 is a schematic optical path diagram of an illumination system according to an embodiment of the present disclosure;

FIG. 6 is a schematic diagram of the structure of the digital micromirror device and the first prism in the illumination system shown in FIG. 2;

FIG. 7 is a schematic diagram illustrating a rear working distance configuration according to an exemplary embodiment of the present disclosure;

fig. 8 is a schematic structural diagram of another illumination system provided in the embodiment of the present application;

fig. 9 is a schematic structural diagram of a projection apparatus according to an embodiment of the present application.

With the above figures, there are shown specific embodiments of the present application, which will be described in more detail below. These drawings and written description are not intended to limit the scope of the inventive concepts in any manner, but rather to illustrate the inventive concepts to those skilled in the art by reference to specific embodiments.

Detailed Description

To make the objects, technical solutions and advantages of the present application more clear, embodiments of the present application will be described in further detail below with reference to the accompanying drawings.

The digital micromirror device can be regarded as an optical switch formed by a plurality of micro-mirrors, namely, the optical switch is switched on and off by utilizing the rotating micro-mirrors, the number of the mirror pieces is determined by the display resolution, one small mirror piece corresponds to one pixel, and the micro-mirror is the minimum working unit and is also the key for influencing the performance of the micro-mirror. The micro-mirrors are very small but still have a complex mechanical structure different from liquid crystal-each micro-mirror has a separate support frame and performs positive or negative n degrees (n > 0) deflection around the hinge tilt axis. Two electrodes are arranged at two corners of the micro mirror, and the deflection of the micro mirror can be controlled by voltage.

The micro-mirror works by means of reflected light, when the micro-mirror is in an open State (English: On State, namely the micro-mirror deflects by + n degrees), namely the incident angle of incident light (light source) reaches n degrees, and the reflection angle also reaches n degrees (the sum of the incident angle and the reflection angle is 2n degrees), at the moment, the energy of the light which can be received by the lens is maximum; if the micro-mirror is deflected to the Off State (i.e., the micro-mirror deflects by-n degrees), the energy of the light received by the lens is minimum, and the brightness is minimum.

Fig. 1 is a schematic structural diagram of an illumination system in the related art. The illumination system includes an illumination mirror group 111, an tir prism 112 and a digital micromirror device 113.

When the light beam S1 exits from the illumination mirror assembly 111, it passes through the tir prism 112 and enters the dmd 113. The long-side incident mode of the digital micromirror device 113 means that light is incident on the side of the digital micromirror device 113 that is long in the thickness direction. The imaging light beam S11 processed by the dmd 113 enters the tir prism 112 and then exits from the tir prism 112 to the projection lens 114, and the non-imaging light beam S12 processed by the dmd 113 also exits from the tir prism 112 to the optical illumination system.

However, since the dmd 113 cannot make all the non-imaging light beams enter the tir prism 112, and then part of the non-imaging light beams S12 enter the projection lens 114, and since the refractive indexes of the light beams with different colors are different, part of the non-imaging light beams S12 emitted from the tir prism 112 enter the projection lens, and thus the contrast of the projection image is low.

Fig. 2 is a schematic diagram of another illumination system in the related art, which includes an illumination mirror group 121, a total reflection inverse prism 122, and a digital micromirror device 123. When the light beam S1 exits from the illumination mirror assembly 121, it passes through the tir prism 122 and enters the dmd 123. Compared with the illumination system in the related art, in which the size of the tir prism 122 is larger, the non-imaging light beam S12 can be totally emitted on the first light-emitting surface of the tir prism 122 and then emitted from the bottom surface, so as to reduce the incidence of the non-imaging light beam S12 output by the dmd 123 on the projection lens 114.

However, the volume of the total reflection prism in the illumination system is large, which results in an increase in the rear working distance of the projection lens, an increase in the volume of the lens, and thus a large overall volume of the illumination device, thereby making the overall volume of the projection apparatus large.

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

As shown in fig. 3, fig. 3 is a lighting system for viewing a digital micromirror device in a plane parallel to the digital micromirror device according to an embodiment of the present application, and the lighting system includes: the digital micro-mirror device 21, the prism assembly 22, the light barrier 23 and the projection lens are arranged in sequence along the optical path direction of the illumination system. The projection lens may include an entrance lens 24 on the lens.

The prism assembly 22 includes a first light incident surface B1 and a first light emitting surface B2, the digital micromirror device 21 is located outside the first light incident surface B1, the light blocking plate 23 is located outside the first light emitting surface B2, and the digital micromirror device 21 is configured to process the received light beam and guide the processed light beam to the first light incident surface B1 of the prism assembly.

As shown in fig. 4, fig. 4 is a schematic structural diagram of a light barrier shown in this embodiment of the application, the light barrier 23 includes an opening region 231 and a shielding region 232, a size of the opening region 231 is greater than or equal to a maximum size of a light spot on a plane where the light barrier 23 is irradiated by an imaging light beam output when a mirror in the digital micromirror device is in an on state, so that the imaging light beam can pass through the opening region 231 to be emitted to the projection lens, and the shielding region 232 of the light barrier 23 is used for blocking a non-imaging light beam output when the mirror in the digital micromirror device is in an off state from being emitted to the projection lens, that is, the light barrier can reduce the non-imaging light beam at the projection lens, and further can reduce an influence of the non-imaging light beam emitted by the digital micromirror device on a contrast of.

For example, as shown in fig. 5, fig. 5 is a schematic optical path diagram of an illumination system shown in the embodiment of the present application, an imaging light beam S3 output by a mirror in a digital micromirror device 21 in an on state can pass through an opening region and be emitted to a light incident lens 24 on a lens, a non-imaging light beam S4 output by the mirror in the digital micromirror device 21 in an off state can be emitted to a blocking region of a light barrier 23, the non-imaging light beam S4 incident to the light incident lens 24 can be reduced, and thus the contrast of a projection display image can be improved.

To sum up, the embodiment of the present application provides an illumination system including a digital micromirror device, a prism assembly, a light barrier and a projection lens, wherein the light barrier includes an opening region and a shielding region, the digital micromirror device processes and then reflects a received light beam, and guides an imaging light beam outputted when a reflector of the digital micromirror device is in an open state to the prism assembly, and the imaging light beam can be emitted to the projection lens through the prism assembly and the opening region of the light barrier, and the shielding region of the light barrier can block a non-imaging light beam outputted when the reflector of the digital micromirror device which is not blocked by the prism assembly is in a closed state from being emitted to the projection lens, that is, the light barrier can reduce the non-imaging light beam emitted to the projection lens, thereby improving contrast of a projection display image while satisfying size miniaturization, and solving the problem of poor quality of the projection display image in the related art, the effect of improving the quality of the projection display picture is achieved.

Optionally, as shown in fig. 3, the prism assembly 22 includes a first prism 221, the first prism 221 is enclosed by a first light incident surface B1, a first light emitting surface B2 and a bottom surface B3, the first light incident surface B1 and the first light emitting surface B2 are perpendicular to each other, and exemplarily, the first prism 221 may be a Total Reflection inverse prism (RTIR), which is an isosceles right triangular prism.

As shown in fig. 5, the non-imaging light beam S4 includes a first light beam S41 emitted to the first light incident surface B1 of the prism assembly 22 and through the bottom surface B3 of the first prism 221, and a second light beam S42 emitted from the digital micro-mirror 21 to the projection lens, and the blocking region 232 of the light barrier includes a first blocking region 2321 for blocking the first light beam S41 and a second blocking region 2322 for blocking the second light beam S42. The first blocking area 2321 of the light blocking plate 23 of the light blocking plate may be used to prevent the first light beam S41 from being incident into the optical lens 24, and the second blocking area 2322 of the light blocking plate 23 of the light blocking plate may be used to prevent the second light beam S42 from being incident into the optical lens 24. Therefore, the non-imaging light beams at the projection lens can be reduced, and the influence of the non-imaging light beams emitted by the digital micro-mirror device on the contrast of a projection display picture can be further reduced.

The light barrier can be positioned between the prism component and the lens, the light barrier can be also connected with the radiating fin, and when the non-imaging light beam emitted by the digital micromirror device is emitted to the light barrier, the radiating fin can reduce the temperature of the periphery of the light barrier and the lens, so that the temperature drift problem can be reduced.

Optionally, as shown in fig. 5, the first prism 221 is configured to receive the imaging light beam S3 through the first light incident surface B1, guide the imaging light beam S3 to the bottom surface B3, and reflect the imaging light beam S3 to the first light emitting surface B2 through the bottom surface B3 to output the first prism 221, where a size of the first light incident surface B1 is greater than or equal to a size of a light spot on a plane where the imaging light beam S3 irradiates the first light incident surface B1. This makes the imaging light beam S3 emitted from the dmd 21 incident on the projection lens completely.

Alternatively, as shown in fig. 6, fig. 6 is a schematic structural diagram of the digital micromirror device 21 and the first prism 221 in the illumination system shown in fig. 2, the digital micromirror device 21 is rectangular, and the short side 211 of the digital micromirror device 21 is parallel to the first light incident surface B1 and perpendicular to the first light emitting surface B2.

Optionally, as shown in fig. 6, the first light incident surface B1 satisfies the formula:

P≥2*L*tanθ+W_DMD；

wherein P is a side length of the first light incident surface B1 (the side length refers to a side length of a side of the first prism 221 parallel to a short side of the dmd 21), and L is a distance from the mirror surface of the dmd 21 to the first prism 221; theta is the numerical aperture angle, W, of the illumination system_DMDIs the short side width of the digital micromirror device.

The numerical aperture angle of the illumination system satisfies the formula: θ ═ arcsin (1/2 × F); wherein F is the F number of the illumination system.

It should be noted that, in the embodiment of the present application, the size of the first prism only needs to be designed according to the size of the imaging light beam emitted by the dmd, so as to satisfy that the imaging light beam of the dmd can completely exit the first prism, and compared to the related art, the size of the tir prism needs to be designed according to the sizes of the imaging light beam and the non-imaging light beam emitted by the dmd at the same time, so as to satisfy that the imaging light beam of the dmd can completely exit the first prism, and at the same time, the non-imaging light beam of the dmd completely enters the tir prism and does not enter the projection lens.

Optionally, as shown in fig. 3, the illumination system further comprises a galvanometer assembly 25, the galvanometer assembly 25 being positioned between the digital micromirror device 21 and the prism assembly 22. The illumination light beam guided by the prism assembly 22 to the digital micromirror device 21 is transmitted to the digital micromirror device 21 after passing through the galvanometer assembly 25, the digital micromirror device 21 modulates the received light beam and then guides the modulated light beam to the galvanometer assembly 25, and the galvanometer assembly 25 processes the light beam emitted by the digital micromirror device 21 and then guides the processed light beam to the prism assembly 22 and guides the processed light beam to a lens through the prism assembly 22. The galvanometer assembly 25 may comprise a flat piece of glass that is vibrated at high frequencies to achieve misaligned transmission of the beam. The galvanometer component 25 is positioned at a position close to the digital micromirror device, and the light beam at the position is converged on the surface of the DMD, so that the light spot is small, the galvanometer component with a smaller size can be selected, and the size of the illumination system can be further reduced.

The illumination system in the embodiment of the application can be adapted to a larger-size digital micromirror device valve (for example, a DMD of 0.66-0.98 inch), so that the size of a projection picture can reach 100-150 inches, and based on the matching of the galvanometer component, the picture can realize the projection imaging quality of 4-8K higher resolution.

Among the laser projector among the correlation technique, the mirror subassembly that will shake is usually placed between reverse total reflection prism and projection lens, the mirror subassembly that shakes can also be including the mirror structure that shakes, when the mirror subassembly that shakes sets up in lighting system, for plain film glass provides power through the mirror structure that shakes, thereby make plain film glass can vibrate the resolution ratio that improves projection equipment, include more parts such as circuit board in the mirror structure that shakes, consequently, the volume of the mirror structure that shakes is bigger than plain film glass's volume, if the mirror subassembly that will shake sets up between prism subassembly and projection lens, the mirror structure that shakes interferes with the circuit board of digital micromirror device each other, consequently, for avoiding structural interference, the structural space distance that can lengthen certainly, lead to the increase of working distance behind the camera lens, the increase of camera lens volume. In the embodiment of the present application, as shown in fig. 3, the galvanometer assembly 25 is disposed between the digital micro-mirror device 21 and the prism assembly 22, and the light beam is an illumination light beam when being emitted from the prism assembly 22 to the digital micro-mirror device 21, and therefore is not affected by the vibration of the galvanometer assembly 25 when passing through the galvanometer assembly 25, and when the light beam enters the digital micro-mirror device 21 and passes through the galvanometer assembly 25 again to reach the light entrance lens 24 of the projection lens, the light beam is an imaging light beam, and at this time, the vibration of the galvanometer assembly 25 can improve the imaging resolution.

As shown in fig. 7, fig. 7 is a schematic structural diagram of a rear working distance according to an embodiment of the present application. Rear working distance (L) of lens_BF) The distance between the lens receiving the light beam of the illumination system and the image plane is referred to as the distance between the incident lens 24 of the projection lens receiving the light beam provided by the illumination system and the digital micromirror device 21, i.e. the sum of the lengths of H1, H2, H3 and H4 in fig. 7. When the size of the first prism (RTIR)221 is reduced, the length of H3 is reduced, and the sum of the lengths of H1, H2, H3, and H4 is reduced, thereby reducing the rear working distance of the projection lens. Wherein H1 is the distance from the digital micromirror device 21 to the galvanometer component 25; h2 is the galvanometer component 25 to the first edgeThe distance of mirror 221; h3 is the length of the right-angle side of the optical cross section of the first prism, the optical cross section is triangular and perpendicular to the plane of the digital micromirror device 21, the right-angle side is the side of the light-emitting surface of the first prism perpendicular to the short side of the digital micromirror device; h4 is the distance from the RTIR to the last lens of the lens.

Wherein, the rear working distance L of the lens_BFThe following formula can be satisfied:

L_BF＝H1+H2+H3+H4。

and since the size of the first prism 221 is reduced while reducing the overall length of the illumination system in the optical axis direction f2, the volume of the illumination system is reduced. In addition, as the rear working distance is reduced, the size of the light incident lens 24 can be reduced, and the size of the lens can be reduced, namely the size of the whole projection device is reduced. Wherein, the rear working distance of the lens and the size of the final lens (i.e. the light entrance lens 24) of the lens can satisfy the following formula:

D_1ens＝2*L_BF*tanθ₂+D_circle。

wherein D is_1ensSize of the lens in the lens for receiving the light beam provided by the illumination system, theta₂For the numerical aperture angle, D, of the projection lens system_circleIs the size of the image circle. An image circle (also called image plane size) is a circular bright and clear image breadth that appears on a focal plane after an incident light ray passes through a projection lens. The image circle of the projection lens is determined by the optical structure of the projection lens, and once the design is completed, the corresponding image circle is determined.

Optionally, as shown in fig. 3, the prism assembly 22 further includes a second prism 222 and a flat glass 223, the second prism 222 is surrounded by a second light incident surface B4, a second light emitting surface B5 and a curved surface B6, the second light emitting surface B5 is opposite to one surface of the flat glass 223, the bottom surface B3 of the first prism 221 is opposite to the other surface of the flat glass, the second light incident surface B4 is configured to receive the light beam S2 and guide the light beam S2 to the curved surface B6, and the curved surface B6 is configured to reflect the light beam S2 to the second light emitting surface B5.

The prism assembly can be used for separating the illuminating light beam and the imaging light beam in the light path, and the second prism can enable the incident direction of the illuminating light beam and the optical axis of the lens to be in the same direction, so that the thickness of the illuminating system is reduced.

The second prism 222 can be used to adjust the direction of the illumination beam to reduce the thickness of the illumination system, and the curved surface B6 of the second prism 222 can reduce the spot size of the illumination beam, thereby further reducing the size of the galvanometer assembly.

The flat glass 223 may be used to increase the distance between the second prism 222 and the first prism 221, so as to avoid the structure of the second prism 222 from interfering with the galvanometer component 25 and the dmd 21.

Alternatively, as shown in fig. 8, fig. 8 is a schematic structural diagram of another illumination system that is provided in this embodiment and looks at the digital micromirror device along a plane perpendicular to the digital micromirror device, the illumination system further includes a light uniformizing assembly 26 and a beam collimating and magnifying lens assembly 27, the light uniformizing assembly 26 is configured to process the received light and then direct the processed light to the beam collimating and magnifying lens assembly 27, and the beam collimating and magnifying lens assembly 27 is configured to direct the light to the prism assembly.

The light homogenizing component can be a light guide pipe or a fly eye lens and can be used for shaping and homogenizing laser spots incident from the light source. Beam homogenization refers to the shaping of a beam with uneven intensity distribution into a beam with uniform cross-section distribution through beam transformation. Laser speckle refers to the interference of light beams to form bright or dark spots, creating random grainy intensity patterns, when a laser light source is used to illuminate a rough surface such as a screen or any other object that produces diffuse reflection or diffuse transmission.

The light guide pipe is a tubular device formed by splicing four plane reflection sheets, namely a hollow light guide pipe, light rays are reflected for multiple times in the light guide pipe to achieve the effect of light uniformization, the light guide pipe can also adopt a solid light guide pipe, the light inlet and the light outlet of the light guide pipe are rectangles with uniform shapes and areas, light beams enter from the light inlet of the light guide pipe and then are emitted from the light outlet of the light guide pipe, and light beam homogenization and laser spot optimization are completed in the process of passing through the light guide pipe. Fly-eye lenses are generally formed by combining a series of small lenses, two arrays of fly-eye lenses are arranged in parallel to divide the light spot of an input laser beam, and the divided light spots are accumulated by a subsequent focusing lens, so that the light beam is homogenized and the light spot is optimized.

Alternatively, as shown in fig. 8, the beam collimating mirror group 27 includes a first lens 271, a second lens 272, and a third lens 273, which are sequentially arranged along the optical path direction f1, where the first lens 271 may be a spherical lens, or may be an aspheric lens; the second lens 272 may be a spherical lens or an aspherical lens; the third lens 273 may be a spherical lens or an aspherical lens. The specific lens specification is selected and not limited herein.

Wherein the main optical axis C2 of the first lens 271 rotates in a counterclockwise direction by a first included angle theta from a state parallel to the main optical axis C1 of the dodging assembly 26₁First angle of inclination theta₁Satisfies the formula:

θ₁<arcsin(2*L₁/D₁)；

wherein, theta₁Is a first angle, L₁The distance between the light outlet of the light homogenizing assembly and the axis of the first lens is; d₁Is the diameter of the first lens.

The first lens 271 is placed obliquely with respect to the main optical axis C1 and may be used to compensate for the optical path; the optical axes of the second lens 272 and the third lens 273, which are parallel to the principal optical axis C1, may be used to converge the light beams and collimate the light rays.

Optionally, as shown in fig. 3, the light beam collimating lens group 27 may further include a plane mirror 274, the plane mirror 274 is configured to receive the light beam emitted from the third lens 273 and guide the light beam to the prism assembly 22, and a plane of the plane mirror 274 and the main optical axis C1 may form an angle of 45 degrees, so that the plane mirror may bend the direction of the light beam emitted from the third lens 273 by 90 degrees to shorten the length of the illumination system along the main optical axis C1, which may reduce the volume of the illumination system.

In addition, a smaller prism assembly may reduce the volume of the illumination system.

As shown in fig. 9, fig. 9 is a schematic structural diagram of a projection apparatus provided in an embodiment of the present application. The projection apparatus includes an illumination system 31, a light source assembly 33, a diffuser assembly 34, and the like.

The illumination system 31 can refer to the illumination system in any of the embodiments described above, the volume of the prism assembly in the illumination system 31 is small, and then the volume of the illumination system 31 is small, the optical height of the illumination system can be as low as 32 mm to 45 mm, so that the volume of the projection device is small, in addition, the projection system 31 is provided with the digital micro-mirror device, the light barrier and the projection lens 311, the light barrier can reduce the non-imaging light beams emitted to the projection lens 311, and then the influence of the non-imaging light beams emitted by the digital micro-mirror device on the contrast of the projection display picture can be reduced, and the quality of the projection display picture of the projection device can be improved.

The diffuser assembly 34 may include a diffuser wheel or diffuser that may be used to despeckle the light beam incident from the light source and direct the despecked light beam to the dodging assembly.

The light source assembly 33 may include a blue laser emitter 331, a green laser emitter 332, a red laser emitter 333, and a light path assembly 334, and the light path assembly 334 may include a first dichroic plate 3341, a second dichroic plate 3342, and a lens assembly 3343, and the dichroic plate refers to a filter that may be almost completely transparent to light of a certain wavelength and almost completely reflective to light of other wavelengths.

The first dichroic filter 3341 may be configured to transmit blue laser light and reflect green laser light, the second dichroic filter 3342 may be configured to transmit red laser light and reflect blue and green laser light, and the lens assembly 3343 may be configured to focus the light and direct the focused light to the diffuser assembly 34.

In summary, the embodiments of the present application provide a projection apparatus including an illumination system, a light source assembly and a diffusion assembly, wherein the illumination system includes a digital micromirror device, a prism assembly, a light barrier and a projection lens. The light barrier comprises an opening area and a shielding area, the digital micromirror device processes the received light beam and then outputs the light beam in a reflecting mode, an imaging light beam output when a reflector of the digital micromirror device is in an open state is guided to the prism assembly, the imaging light beam can irradiate to the projection lens through the prism assembly and the opening area of the light barrier, the shielding area of the light barrier can block a non-imaging light beam output when the reflector of the digital micromirror device which cannot be blocked by the prism assembly is in a closed state from irradiating to the projection lens, namely the light barrier can reduce the non-imaging light beam irradiating to the projection lens, the contrast of a projection display picture can be improved while the size miniaturization is met, the problem that the quality of the projection display picture in the related technology is poor is solved, and the effect of improving the quality of the projection display picture is achieved.

In addition, a smaller prism assembly can reduce the volume of the illumination system, thereby enabling the volume of the projection device to be smaller.

In this application, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. The term "plurality" means two or more unless expressly limited otherwise.

The above description is only exemplary of the present application and should not be taken as limiting, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. An illumination system is characterized by comprising a digital micro-mirror device, a prism component, a light barrier and a projection lens which are sequentially arranged along the light path direction of the illumination system;

2. The illumination system of claim 1, wherein the prism assembly comprises a first prism, the first prism is enclosed by the first light incident surface, the first light emitting surface, and a bottom surface, and the first light incident surface and the first light emitting surface are perpendicular to each other;

3. The illumination system of claim 2, wherein the first prism is configured to receive the imaging beam through the first light incident surface and direct the imaging beam to the bottom surface, the bottom surface reflects the imaging beam toward the first light emergent surface to output the first prism, and the size of the first light incident surface is greater than or equal to the size of a light spot of the imaging beam on a plane where the first light incident surface is located.

4. The illumination system of claim 3, wherein the DMD is rectangular, and a short side of the DMD is parallel to the first light-in surface and perpendicular to the first light-out surface.

5. The illumination system of claim 3, wherein the first entrance surface satisfies the formula:

P≥2*L*tanθ+W_DMD；

6. The illumination system of claim 2, wherein the prism assembly further comprises a second prism and a flat glass, the second prism is enclosed by a second light incident surface, a second light emitting surface and a curved surface, the second light emitting surface is opposite to one surface of the flat glass, the bottom surface of the first prism is opposite to the other surface of the flat glass, the second light incident surface is used for receiving the light beam and guiding the light beam to the curved surface, and the curved surface is used for reflecting the light beam to the second light emitting surface.

7. An illumination system according to any of claims 1-6, further comprising a galvanometer assembly, the galvanometer assembly being positioned between the digital micromirror device and the prism assembly.

8. An illumination system according to any of claims 1-6, further comprising a dodging assembly for processing the received light beam and directing it to said set of beam collimating and magnifying lenses for directing it to said prism assembly, and a set of beam collimating and magnifying lenses for directing it to said prism assembly.

9. The illumination system of claim 8, wherein the light beam collimating and magnifying lens group comprises a first lens, a second lens and a third lens, which are sequentially arranged along the light path direction, and a main optical axis of the first lens is rotated by a first included angle along a counterclockwise direction from a state parallel to a main optical axis of the dodging assembly, and the first included angle satisfies a formula:

θ₁＜arcsin(2*L₁/D₁)；

10. A projection device comprising an illumination system as claimed in any one of the claims 1 to 9.