Projection equipment

Abstract

The present application discloses a projection device, belonging to the field of optoelectronic technology. The projection device includes a light source, a light valve, and a lens, a first convex lens, a first diffuser, a second convex lens, and a light homogenizing component located in the light path between the light source and the light valve; the focal points of the first convex lens and the second convex lens coincide with each other, and the coincident focal point is located between the first convex lens and the second convex lens; the first diffuser is located at the focal point; the first convex lens is used to converge the light emitted by the light source to the first diffuser, the first diffuser is used to expand the divergence angle of the incident light and then direct it to the second convex lens, the second convex lens is used to direct the incident light to the light homogenizing component, and the light homogenizing component is used to homogenize the incident light and then direct it to the light valve, and the light spot area on the first convex lens is larger than the light spot area on the second convex lens. The present application solves the problem of poor display effect of the projection screen of the projection device. The present application is used for projection.

Description

Technical Field

[0001] The present application relates to the field of optoelectronic technology, and in particular to a projection device. Background Art

[0002] With the development of optoelectronic technology, the requirements for the display effect of the projection screen of the projection equipment are getting higher and higher.

[0003] Figure 1 This is a schematic diagram of the structure of a projection device provided by the related technology. Figure 1 As shown, the projection device 00 includes: a light source 001, a light pipe 0021, an illumination lens assembly 0022, a light valve 0024, and a lens 003. The light pipe 0021 is strip-shaped, and the light inlet D1 and the light outlet D2 of the light pipe 0021 are located in the longitudinal direction (as shown in FIG. Figure 1 The light source 001 injects light into the light inlet D1 of the light guide 0021. The light guide 0021 homogenizes the light transmitted therethrough, and the light is then emitted from the light outlet D2 of the light guide 0021 to the illumination lens assembly 0022. The illumination lens assembly 0022 adjusts the transmission direction of the incident light and directs it toward the light valve 0024. The light valve 0024 modulates the incident light to direct the light required for imaging toward the lens 003. The lens 003 then projects the light to form a projection image.

[0004] In the aforementioned projection device architecture, to achieve greater light spot uniformity and thus ensure a uniform projection image, a light guide with excellent light homogenization is desired. This homogenization effect is generally proportional to its length, resulting in a typically long light path length, hindering the miniaturization of the optical path architecture. Furthermore, the light guide's light inlet has a limited range of incident angles. Light beams outside this range are considered stray light and cannot enter the light guide, thus failing to be utilized by the back-end light valve, resulting in low optical efficiency.

[0005] Furthermore, when using a laser light source, especially one emitting multi-color lasers, to ensure projected image quality, a speckle reduction component must be incorporated into the optical path. For example, a rotating diffuser can be placed in the optical path before the light pipe entrance to improve the coherence of the laser beam. However, this further increases the length and volume of the optical path. Adding a new speckle reduction component to an existing optical path architecture typically alters the optical path layout, making the architecture larger and more complex. Summary of the Invention

[0006] The present application provides a projection device that can solve the problems of poor display quality and large size of projection devices. The projection device includes: a light source, a light valve, and a lens. The light source is used to emit light to the light valve. The light valve is used to modulate the incident light and then direct it toward the lens. The lens is used to project the incident light.

[0007] The projection device further includes: a first convex lens, a first diffuser, a second convex lens, and a light uniforming component located in a light path between the light source and the light valve; the focal points of the first convex lens and the second convex lens coincide with each other, and the coincident focal points are located between the first convex lens and the second convex lens; the first diffuser is located at the focal points;

[0008] The first convex lens is used to converge the light emitted by the light source to the first diffuser, the first diffuser is used to expand the divergence angle of the incident light and then direct it toward the second convex lens, the second convex lens is used to direct the incident light toward the light uniforming component, and the light uniforming component is used to uniformize the incident light and then direct it toward the light valve. The light spot area on the first convex lens is larger than the light spot area on the second convex lens.

[0009] The beneficial effects of the technical solution provided by this application include at least:

[0010] In the projection device provided by the present application, a first convex lens, a first diffuser, a second convex lens and a light homogenizing component are arranged in sequence in the light emitting direction of the light source. The focal points of the first convex lens and the second convex lens coincide with each other, and the spot area on the first convex lens is larger than the spot area on the second convex lens. The first convex lens and the second convex lens can be used to reduce the light emitted by the light source, ensuring that more light is directed to the light homogenizing component for forming a projection screen, thereby ensuring that the utilization rate of light is high. And because the first diffuser is located at the coincident focus, on the one hand, according to the principle of light beam convergence imaging, the light at the focus (convergence imaging point) can be emitted from a point light source at any beam angle to the lens, and can be collimated into a parallel beam by the lens. Therefore, the first diffuser can be set to a larger divergence angle to diffuse the incident laser beam to a greater extent, so that the homogenization effect of the laser beam is good, and after the laser beam after large-angle diffusion is directed to the second convex lens, it can still be converged into a collimated state by the second convex lens.

[0011] Furthermore, the spot size of the laser beam collimated by the second convex lens is reduced, achieving beam contraction, which in turn facilitates the use of subsequent optical lenses. In this technical solution, there is no need to create a dedicated optical path location for the first diffuser. Instead, it is located between the two existing lenses, achieving the dual functions of beam contraction and speckle reduction without increasing the optical path length.

[0012] Therefore, the projection device can expand the divergence angle of the light emitted by the light source to reduce the coherence of the light without affecting the light convergence and ensuring that the light utilization rate and optical path length do not increase, thereby reducing the speckle effect of the projection device and improving the display effect of the projection screen of the projection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0014] Figure 1 It is a structural diagram of a projection device provided by the related art;

[0015] Figure 2 This is a schematic structural diagram of a projection device provided in an embodiment of the present application;

[0016] Figure 3 is a structural schematic diagram of another projection device provided in an embodiment of the present application;

[0017] Figure 4 This is a partial structural diagram of a projection device provided in an embodiment of the present application;

[0018] Figure 5 1 is a schematic structural diagram of another projection device provided in an embodiment of the present application;

[0019] Figure 6 This is a structural diagram of another projection device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0020] In order to make the objectives, technical solutions and advantages of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0021] With the development of optoelectronic technology, the requirements for miniaturization of projection equipment are getting higher and higher. Figure 1 This is a schematic diagram of the structure of a projection device provided by the related technology. Figure 1 As shown, the projection device 00 may include: a light source 001, an optical machine ( Figure 1Not marked), lens 003. The light source 001 may include a laser 0011, a light combining lens group 0012 and a converging lens 0013. The laser 0011 may emit light (such as red, green and blue lasers) to the light combining lens group 0012, and the light combining lens group 0012 may mix the light emitted by the laser 0011 and direct the mixed light toward the converging lens 0013, and the converging lens 0013 may converge the incident light and direct it toward the optical machine. The optical machine may include: a diffuser 0020, a light pipe 0021, an illumination lens group 0023 and a light valve 0024. The light pipe 0021 is in the shape of a strip, and the light inlet D1 and the light outlet D2 of the light pipe 0021 are located in the length direction thereof (such as Figure 1 The light source 001 emits light toward the diffuser 0020. After being diffused by the diffuser 0020, the light enters the light inlet D1 of the light guide 0021. The light guide 0021 homogenizes the light transmitted therein, and the light is emitted from the light outlet D2 of the light guide 0021 to the illumination lens assembly 0023. The illumination lens assembly 0023 includes a light-collecting lens assembly consisting of two lenses, a reflector F, a lens T4, and a total internal reflection (TIR) ​​prism L. Figure 1 As shown, the light-collecting lens group includes lens T1 and lens T2. The light can first enter lens T1, diffuse in lens T1, and be collimated when exiting lens T1 and then be emitted to lens T2. The lens T2 can further collimate the incident light and then emit it to reflector F, which reflects the light to lens T4. Then lens T4 converges the light to the total internal reflection prism L. The total internal reflection prism L can adjust the transmission direction of the light and then emit the light to the light valve 0024. The light valve 0024 includes a plurality of pixels. The light valve 0024 can emit the incident light to the lens according to the image to be displayed so that the pixels that need to be displayed in a bright state can be made to display the pixels in the light valve 0024, so as to achieve light modulation. Lens 003 is located on the side of the total internal reflection prism L away from the light valve 0024. Lens 003 may include a plurality of lenses ( Figure 1 Not shown), for Figure 1 In the arrangement of the various components of optical engine 00 shown, the lenses of lens 003 should be arranged in a sequence perpendicular to the paper and pointing outward. Light emitted from light valve 0024 can then pass through the multiple lenses of lens 003 and reach the screen, thereby projecting the light and displaying the projected image.

[0022] It should be noted that using a laser as the light source for projection displays often produces a speckle effect. The speckle effect refers to the effect where two laser beams emitted by a coherent light source, when scattered upon a rough object (such as the projection screen), interfere with each other in space, ultimately resulting in the appearance of granular, alternating light and dark spots on the screen. Two adjacent light-emitting chips in a laser that emit laser light of the same wavelength and constant phase are coherent light sources. The speckle effect results in poor display quality for the projected image, and these unfocused, alternating light and dark spots appear flickering to the human eye, causing dizziness after prolonged viewing and a poor viewing experience for the user. The diffuser 0020 in the optical engine diffuses the light emitted by the light source 001 to reduce its coherence. However, the light diffused by the diffuser 0020 has a large divergence angle, preventing much light from entering the light guide, resulting in low light utilization. This, in turn, reduces the brightness and angle of the projection screen, resulting in poor display quality for the projection screen.

[0023] Furthermore, because the related art uses a light pipe as the light homogenizing component in the optical engine, and the length of the light pipe is positively correlated with its light homogenization effect, the light pipe must be designed to be long to ensure high uniformity of the light emitted by the optical engine. Consequently, the light pipe takes up a lot of space, making the optical engine bulky and making it difficult to miniaturize the projection equipment.

[0024] The following embodiments of the present application provide a projection device that can provide a better display effect of the projected image and can also be easily miniaturized.

[0025] Figure 2 This is a schematic diagram of the structure of a projection device provided in an embodiment of the present application. Figure 2 As shown, the projection device 00 includes: a light source 20, a light valve 103 and a lens 30. The light source 20 is used to emit light to the light valve 103. The light valve 103 is used to modulate the incident light and then emit it to the lens 30. The lens 30 is used to project the incident light.

[0026] The projection device 00 further includes: a first convex lens 1041, a first diffuser 105, a second convex lens 1042, and a light homogenizing component 101 located in the light path between the light source 20 and the light valve 103. For example, the first convex lens 1041, the first diffuser 105, the second convex lens 1042, and the light homogenizing component 101 can be arranged along the light output direction of the light source 20 (e.g., Figure 2 The first convex lens 1041 and the second convex lens 1042 have their focal points overlapped, and the overlapped focal point is located between the first convex lens 1041 and the second convex lens 1042. The first diffuser 105 is located at this focal point. Optionally, the optical axes of the first convex lens 1041 and the second convex lens 1042 can be collinear.

[0027] The first convex lens 1041 can converge the light incident from the light source 20 to its focal point. Therefore, the first convex lens 1041 can converge the light emitted by the light source 20 to the first diffuser 105. The first diffuser 105 is used to expand the divergence angle of the incident light before directing it toward the second convex lens 1042. The second convex lens 1042 is used to direct the incident light toward the light homogenizing component 101. The light homogenizing component 101 is used to homogenize the incident light before directing it toward the valve 103. The first convex lens 1041 and the second convex lens 1042 can form a focusing component to focus the light incident on the first convex lens. Therefore, the light spot area on the first convex lens 1041 is larger than the light spot area on the second convex lens 1042. In other words, the light spot area formed by the light emitted from the light source on the first convex lens 1041 is larger than the light spot area formed by the light emitted from the first diffuser 105 on the second convex lens 1042.

[0028] In the embodiment of the present application, the light source 20 and the lens 30 can refer to Figure 1 The introduction of light source 001 and lens 003 can be referred to in Figure 1 The relevant introduction of the light valve 0024 will not be repeated in the embodiments of this application.

[0029] Optionally, the light emitted by the light source toward the first convex lens 1041 can be parallel to the optical axis of the first convex lens 1041, or approximately parallel to the optical axis (that is, the angle between the light and the optical axis is less than a certain angle threshold). Since the convex lens can converge the light parallel to the optical axis at the focus, and the convex lens can change the light incident from its focus into light parallel to the optical axis. Therefore, the light emitted by the light source can converge at its focus after passing through the first convex lens 1041, and the light can then be emitted toward the second convex lens 1042, and become parallel light through the second convex lens 1042. At this time, the light source 20 may not include a converging lens, or the converging lens may be replaced with a collimating lens to ensure that the light emitted by the light source toward the optical machine is parallel light or approximately parallel light.

[0030] In the embodiment of the present application, since the light rays converge at the focal point and then continue to be transmitted to the second convex lens 1042, the spot area on the first convex lens 1041 is larger than the spot area on the second convex lens 1042. In other words, the lens group consisting of the first convex lens 1041 and the second convex lens 1042 can narrow the input light beam, ensuring that more light rays are directed to the light uniforming component for forming the projection image, thereby ensuring high light utilization.

[0031] In the embodiment of the present application, the first diffuser is located at the focal point of the second convex lens. Therefore, even if the diffusion angle of the first diffuser is large, it can ensure that the light emitted from the first diffuser can be emitted to the second convex lens with a large divergence angle range and still be collimated to be approximately parallel light. In this way, the projection device can expand the divergence angle of the light emitted by the light source to reduce the coherence of the light without affecting the light convergence and ensuring light utilization, thereby reducing the speckle effect of the projection device and improving the display quality of the projection image of the projection device. Moreover, since the loss of light directed to the light homogenizing component is relatively small, the optical collection efficiency of the light homogenizing component can be ensured to be high. The larger the diffusion angle of the diffuser, the lower the coherence of the light passing through the diffuser. In the embodiment of the present application, the first diffuser is located at the focal point of the first and second convex lenses. Even if the diffusion angle of the first diffuser is large, it will not affect the light convergence of the first and second convex lenses. Therefore, the diffusion angle of the first diffuser can be large, and the diffuser has a high degree of homogenization of the laser beam, ensuring a better elimination of the speckle effect.

[0032] In the embodiment of the present application, the first diffuser is disposed between the first convex lens and the second convex lens. This eliminates the need for a separate location for disposing the first diffuser, and the components in the optical machine are compactly arranged, thereby reducing the speckle effect while ensuring that the size of the optical machine is small.

[0033] In summary, in the projection device provided by the embodiment of the present application, a first convex lens, a first diffuser, a second convex lens and a light homogenizing component are arranged in sequence on the light path between the light source and the light valve. The focal points of the first convex lens and the second convex lens coincide with each other, and the spot area on the first convex lens is larger than the spot area on the second convex lens. The first convex lens and the second convex lens constitute a beam reduction system, which can reduce the light emitted by the light source, ensuring that more light is directed to the light homogenizing component for forming a projection screen, thereby ensuring that the utilization rate of the light is high. And because the first diffuser is located at the coincident focus, on the one hand, according to the principle of light beam convergence and imaging, the light at the focus (convergence imaging point) can be emitted from a point light source at any beam angle to the lens, and can be collimated by the lens into a parallel beam. Therefore, the first diffuser can be set to a larger divergence angle to diffuse the incident laser beam to a greater extent, so that the laser beam has a good homogenization effect. After the laser beam is diffused at a large angle and is directed to the second convex lens, it can still be collimated by the second convex lens into a parallel beam or an approximately parallel beam.

[0034] Furthermore, the spot size of the laser beam collimated by the second convex lens is reduced, achieving beam contraction, which in turn facilitates the use of subsequent optical lenses. In this technical solution, there is no need to create a dedicated optical path location for the first diffuser. Instead, it is located between the two existing lenses, achieving the dual functions of beam contraction and speckle reduction without increasing the optical path length.

[0035] Therefore, the projection device can expand the divergence angle of the light emitted by the light source to reduce the coherence of the light without affecting the light convergence and ensuring that the light utilization rate and optical path length do not increase, thereby reducing the speckle effect of the projection device and improving the display effect of the projection screen of the projection device.

[0036] In an optional implementation, the focal length of the first convex lens 1041 in the embodiment of the present application is greater than the focal length of the second convex lens 1042. Therefore, the distance between the first convex lens 1041 and the overlapping focal point of the first diffuser 105 is greater than the distance between the second convex lens 1042 and the overlapping focal point. The optical path of light from the overlapping focal point to the second convex lens 1042 is shorter, the divergence angle of the light when it reaches the second convex lens is smaller, and the light spot formed by the light on the second convex lens 1042 is smaller. This ensures that the light spot area on the first convex lens 1041 is larger than the light spot area on the second convex lens 1042.

[0037] Optionally, the ratio of the spot area on the first convex lens 1041 to the spot area on the second convex lens 1042 can be in the range of 1.5 to 3. That is, the focusing ratio of the focusing component composed of the first convex lens 1041 and the second convex lens 1042 to the light is in the range of 1.5 to 3 times. Optionally, the focusing ratio of the focusing component to the light can be designed accordingly according to the specific structure of the light source 20. If the light source 20 includes two lasers, the focusing ratio of the focusing component to the light can be in the range of 1.5 to 2 times; if the light source includes three lasers, the focusing ratio of the focusing component to the light can be in the range of 2 to 3 times.

[0038] Optionally, the orthographic projection area of ​​the first convex lens 1041 on a plane perpendicular to its optical axis is larger than the orthographic projection area of ​​the second convex lens 1042 on the same plane, that is, the size of the first convex lens 1041 is larger than the size of the second convex lens 1042, and the aperture of the first convex lens 1041 is larger than the aperture of the second convex lens 1042. The light spot formed by the light on the second convex lens 1042 can be smaller than the light spot formed by the light on the first convex lens 1041, so the size of the first convex lens 1041 can be larger than the size of the second convex lens 1042, avoiding the waste of convex lenses caused by providing a larger second convex lens 1042.

[0039] Optionally, the center of the first diffusion sheet 105 may coincide with the focus of the first convex lens 1041 and the second convex lens 1042. The first diffusion sheet 105 may be perpendicular to the arrangement direction of the first convex lens 1041 and the second convex lens 1042 (ie, Figure 2), that is, the first diffuser 105 is located at the focal plane where the first convex lens 1041 and the second convex lens 1042 overlap. Optionally, the diffusion angle of the first diffuser 105 ranges from 8 degrees to 16 degrees.

[0040] The first diffuser 105 can be a plate-like structure. It can include two larger surfaces and multiple smaller side surfaces connecting the two larger surfaces. The two larger surfaces are parallel. The first diffuser 105 is perpendicular to the x-direction, that is, the two larger surfaces of the first diffuser 105 are perpendicular to the x-direction. Because the first diffuser 105 is very thin, the thickness is equal to the distance between the two larger surfaces. Therefore, it can be directly considered that the first diffuser 105 is perpendicular to the x-direction.

[0041] The light source 20 of the embodiment of the present application can emit lasers of at least two colors. When the light emitted by the light source is laser, the projection device will produce a speckle effect, so a diffuser is required to reduce the speckle effect. Optionally, the at least two colors of lasers may include: a laser with a first divergence angle and a laser with a second divergence angle, and the first divergence angle is greater than the second divergence angle. For example, the at least two colors of lasers may include: a red laser, a green laser, and a blue laser, wherein the divergence angle of the red laser is greater than the divergence angles of the blue laser and the green laser, so the red laser is a laser with a first divergence angle, and the green laser and the blue laser are lasers with a second divergence angle.

[0042] Based on the light source 20, the first diffuser 105 in the embodiment of the present application may include a first diffuser region and a second diffuser region, wherein the diffusion angle of the first diffuser region is smaller than the diffusion angle of the second diffuser region. The laser light of the first divergence angle can be emitted to the first diffuser region, and the laser light of the second divergence angle can be emitted to the second diffuser region. Since the divergence angle of the laser light emitted to the first diffuser region is greater than the divergence angle of the laser light emitted to the second diffuser region, and the diffusion angle of the first diffuser region is smaller than the diffusion angle of the second diffuser region, this ensures that the difference in the divergence angles of the laser light of different colors emitted from the first diffuser and originally having different divergence angles is small, thereby ensuring the uniformity of the laser light used for projection and further improving the display effect of the projected image.

[0043] Optionally, the first diffuser 105 can be a movable diffuser. The light source 20 can emit at least two colors of light in a time sequence, and the movement of the first diffuser 105 is related to the time sequence. The movement of the first diffuser (such as movement speed and direction) can be appropriately adjusted to ensure that when the light source 20 emits laser light with a first divergence angle, the first diffusion area of ​​the first diffuser 105 is located in the illumination area of ​​the laser light; and when the light source 20 emits laser light with a second divergence angle, the second diffusion area of ​​the first diffuser 105 is located in the illumination area of ​​the laser light.

[0044] In the embodiment of the present application, the light homogenizing component 101 may include a fly-eye lens. The fly-eye lens has a good light homogenizing effect, and the light homogenizing effect of the fly-eye lens is independent of its thickness. Therefore, a thinner fly-eye lens can ensure a good light homogenizing effect, further ensuring the miniaturization of the projection device.

[0045] Optionally, the fly-eye lens has a better homogenization effect on parallel light, and the light directed to the fly-eye lens can be parallel light or approximately parallel light. Optionally, the optical axes of the first convex lens 1041, the second convex lens 1042, and the fly-eye lens can be collinear. It should be noted that in the embodiment of the present application, a beam reduction component is provided between the light source and the fly-eye lens to reduce the light spot directed to the fly-eye lens. In this way, the size of the fly-eye lens can be smaller. Since the cost of the fly-eye lens is relatively high, the cost of the fly-eye lens can be saved, thereby saving the manufacturing cost of the projection equipment.

[0046] Please continue to refer to Figure 2 The fly-eye lens may include a plurality of lens units Y. For example, the plurality of lens units Y may be arranged in an array. The fly-eye lens may satisfy at least one of the following:

[0047] The orthographic projection area of ​​the compound eye lens on a plane perpendicular to the optical axis of the compound eye lens ranges from 144 square millimeters to 265 square millimeters;

[0048] The orthographic projection of the fly-eye lens on a plane perpendicular to the optical axis of the fly-eye lens is a rectangle, and the aspect ratio of the rectangle ranges from 1.6 to 2;

[0049] The maximum distance between the two ends of the lens unit Y in the direction perpendicular to the optical axis ranges from 0.5 mm to 1.5 mm;

[0050] Furthermore, the light transmittance of the fly-eye lens ranges from 98% to 99%.

[0051] It should be noted that Figure 2 Only six lens units Y in the fly-eye lens are shown. Optionally, the number of lens units Y in the fly-eye lens can be set according to the shape and size of the lens units Y and the size of the fly-eye lens. For example, the number of lens units Y in the fly-eye lens can also be 10, 20, 50, or even more, which is not limited in this embodiment of the present application.

[0052] For example, the orthographic projection of the fly-eye lens on a plane perpendicular to the optical axis of the fly-eye lens (i.e., a plane perpendicular to the x-direction) can be a quadrilateral. If the quadrilateral is a square, the side length of the square can range from 12 mm to 25 mm. Optionally, the orthographic projection of the fly-eye lens on the plane can also be other shapes, such as a rectangle, a circle, or an ellipse, etc., which is not limited in this embodiment of the present application.

[0053] As another example, the orthographic projection of the lens unit Y on a plane perpendicular to the optical axis of the fly-eye lens can be circular, elliptical, quadrilateral, hexagonal, or other shapes. If the orthographic projection of the lens unit Y on the plane is circular, the distance between the two ends of the lens unit Y in the direction perpendicular to the optical axis is the diameter of the circle. If the orthographic projection of the lens unit Y on the plane is elliptical, the maximum distance between the two ends of the lens unit Y in the direction perpendicular to the optical axis is the major axis of the ellipse. If the orthographic projection of the lens unit Y on the plane is rectangular, the maximum distance between the two ends of the lens unit Y in the direction perpendicular to the optical axis is the length of the rectangle. If the orthographic projection of the lens unit Y on the plane is hexagonal, the maximum distance between the two ends of the lens unit Y in the direction perpendicular to the optical axis is the length of the longest diagonal of the rectangle.

[0054] Since the light spot on the fly-eye lens is in an object-image relationship with the light spot on the light valve 103, the aspect ratio of the light spot on the fly-eye lens is the same as that of the light spot on the light valve 103. Therefore, the fly-eye lens can be designed based on the light valve 103. For example, the fly-eye lens can be designed so that the aspect ratio of its orthographic projection on a plane perpendicular to its optical axis is the same as that of the light valve 103, for example, the aspect ratio range is 1.6 to 2.

[0055] In the related art, a light guide is used as a light uniforming component. The light loss during transmission in the light guide is high, and the light transmittance of the light guide is low. In addition, the light guide is in the shape of an elongated strip, the size of the light inlet of the light guide is small, and the light incident angle of the light guide is small. For example, the center of the light inlet of the light guide can be located on the optical axis of the converging lens. The light can only be incident on the light guide when the angle between the light emitted by the converging lens and the optical axis of the converging lens is within the light incident angle range of the light guide. Usually, the light incident angle of the light guide is less than 23 degrees, and there are many light rays in the light emitted by the converging lens that have an angle with the optical axis greater than 23 degrees. These light rays will be wasted, so more light emitted by the light source is wasted, and the utilization rate of the light emitted by the light source is low.

[0056] In the embodiments of the present application, the fly-eye lens can achieve a light transmittance of 98% to 99%. This transmittance is greater than that of the light guide, thus reducing light loss during the homogenization process. Furthermore, the fly-eye lens can be larger than the light guide's light inlet, allowing more light from the light source to be directed toward the fly-eye lens, where it is then homogenized before being emitted. This results in high light utilization, minimal light loss, and a higher optical efficiency for the optical machine.

[0057] Figure 3 This is a schematic diagram of the structure of another projection device provided in an embodiment of the present application. Figure 3As shown, the projection device 00 may further include: a second diffuser 106, the second diffuser 106 being located between the second convex lens 1042 and the light uniforming component 101. Optionally, the diffusion angle of the second diffuser 106 may be smaller than the diffusion angle of the first diffuser 105. For example, the diffusion angle of the second diffuser 106 ranges from 1 degree to 6 degrees. Optionally, the second diffuser 106 may be fixedly arranged. Optionally, the second diffuser 106 may also be located in the light path before the light emitted by the light source 20 is incident on the first convex lens 1041, such as the second diffuser 106 may also be located between the light source 20 and the first convex lens 1041. This embodiment of the present application does not illustrate this approach.

[0058] In the embodiment of the present application, in addition to providing the first diffuser 105, a second diffuser 106 can be provided to further assist the first diffuser 105 in diffusing and homogenizing the light, thereby further reducing the speckle effect of the projection device. Furthermore, because the second diffuser 106 is located close to the light homogenizing component 101, and the light passing through the second diffuser 106 is transmitted according to its exit angle, the diffusion angle of the second diffuser 106 is reduced, thereby preventing the light passing through the second diffuser 106 from being emitted outside the light homogenizing component 101 due to its large divergence angle, resulting in light waste. Furthermore, because the lens group 104 focuses the light, the spot size of the light incident on the second diffuser 106 is smaller, and the area of ​​the second diffuser 106 can also be smaller, further reducing the manufacturing cost of the optical machine.

[0059] Optionally, please continue to refer to Figure 3 The projection device 00 may further include: a first driving structure 107 and / or a second driving structure 108 . Figure 3 Take the projection device as an example, which includes both a first drive structure 107 and a second drive structure 108. The first drive structure 107 is used to drive the diffuser (such as the first diffuser 105 and the second diffuser 106) between the light source and the light uniforming component 101 to move along the target direction, which intersects with the arrangement direction of the light source and the light uniforming component 101 (i.e., the x-direction). For example, the target direction is perpendicular to the x-direction, such as the target direction can be the y-direction, or the target direction is perpendicular to both the x-direction and the y-direction (i.e., the direction perpendicular to the paper). The second drive structure 108 is used to drive the diffuser to rotate around an axis parallel to the arrangement direction of the light source and the light uniforming component 101 (i.e., the x-direction).

[0060] The diffuser includes microstructures with varying diffusion angles arranged in a regular pattern. For example, these microstructures can resemble miniature convex lenses. As the diffuser moves, it ensures that light strikes different locations on the diffuser at different times. This allows the projection device to project speckles of varying shapes and positions based on the light at different times to overlap, effectively eliminating visible speckle.

[0061] It should be noted that, only one of the first diffuser 105 and the second diffuser 106 can move under the drive of the at least one driving structure, or both diffusers can move under the drive of the at least one driving structure, and the movement modes of the two diffusers can be the same or different, which is not limited in the embodiment of the present application. For example, Figure 3 The first diffusion sheet 105 moves under the driving of the first driving structure 107 , and the second diffusion sheet 106 moves under the driving of the second driving structure 108 .

[0062] Optionally, please continue to refer to Figure 2 and Figure 3 The projection device 00 may further include: an illumination lens group 102 located between the light-uniform component 101 and the light valve 103. The illumination lens group 102 may include: a third convex lens T3, a reflector F, a fourth convex lens T4, and a total internal reflection prism L. The light emitted from the light-uniform component 101 may be directed toward the reflector F through the third convex lens T3, and the reflector F may reflect the incident light to the fourth convex lens T4, and the fourth convex lens T4 may converge the incident light to the total internal reflection prism L, and the total internal reflection prism L may reflect the incident light to the light valve 103. It should be noted that for the introduction of the illumination lens group 102, reference may be made to the description of Figure 1 Related introduction of medium lighting mirror group 0023.

[0063] It should be noted that in the related art, the light emitted from the light guide needs to pass through at least two lenses before it is emitted to the reflector. However, in the embodiment of the present application, the beam reduction component composed of the first convex lens and the second convex lens can emit parallel light, and the light emitted by the compound eye lens has a high degree of collimation. Therefore, it is only necessary to reduce the divergence angle of the light through a light-collecting convex lens (that is, the third convex lens) to obtain light that meets the modulation requirements of the light valve, and then make the light sequentially emitted to the reflector, the fourth convex lens and the light valve. Since the number of light-collecting lenses between the light-uniform component and the reflector is reduced in the embodiment of the present application, the volume of the projection device can be further ensured to be small, which facilitates the miniaturization of the projection device.

[0064] Figure 4 This is a partial structural diagram of a projection device provided in an embodiment of the present application, in which only partial structures and light valves in the illumination mirror assembly are illustrated. Figure 4 The lighting mirror assembly 102 and light valve 103 shown can be Figure 2 or Figure 3 The left side view of the lighting mirror group 102 and the light valve 103 in FIG. Figure 2 or Figure 3 The lighting mirror group 102 and the light valve 103 in the embodiment can be Figure 4 The top view of the lighting mirror assembly 102 and the light valve 103 shown in FIG. 1 is a view after being rotated 90 degrees clockwise. Figure 4 As shown, the total internal reflection prism L in the lighting lens assembly 102 may include two triangular prisms (a first prism L1 and a second prism L2). The second prism L2 may be located on the side of the first prism L1 away from the light valve 103. An air gap may exist between the two adjacent surfaces of the first prism L1 and the second prism L2, thereby forming a total internal reflection prism. This ensures that light entering the first prism L1 is totally reflected on the side of the first prism L1 closest to the second prism L2, and then exits the first prism L1 and is directed toward the light valve 103. The light valve 103 can reflect the light, allowing it to sequentially pass through the first prism L1 and the second prism L2 and then be directed toward the lens. Optionally, the light path of the light in the lighting lens assembly 102 may also be referred to as the illumination light path.

[0065] Optionally, the light valve in the embodiment of the present application can be modified to adapt to the different projection architectures of the projection device. For example, the light valve can be Liquid Crystal on Silicon (LCOS), Liquid Crystal Display (LCD) or Digital Micromirror Device (DMD). The embodiment of the present application is explained by taking the projection device adopting the Digital Light Processing (DLP) architecture and the light valve being the DMD as an example. For example, the DMD includes a plurality of tiny reflective plates (not shown in the figure), each of which can be regarded as a pixel, and the light reflected by each reflective plate can be used to display a pixel point in the projection image. The reflective plate can be in two states. In the first state, the reflective plate can reflect the incident light to the lens. In the second state, the reflective plate can reflect the incident light outside the lens, thereby realizing the light and dark display of the pixel. For example, when the reflective plate is rotated by positive 17 degrees or positive 12 degrees from the initial state, the reflective plate can be in the first state. When the reflective plate is rotated by negative 17 degrees or negative 12 degrees from the initial state, the reflective plate can be in the second state. For example, if Figure 3The light valve shown represents a reflector. The reflector can be in a first state, where its initial state is parallel to the side surface of the first prism L1 it is proximate to. A clockwise rotation angle of the reflector from its initial state is considered a positive angle, while a counterclockwise rotation angle from its initial state is considered a negative angle. By adjusting the states of the individual reflectors in the DMD, the projection device can project a corresponding image.

[0066] In summary, in the projection device provided by the embodiment of the present application, a first convex lens, a first diffuser, a second convex lens and a light homogenizing component are arranged in sequence on the light path between the light source and the light valve. The focal points of the first convex lens and the second convex lens coincide with each other, and the spot area on the first convex lens is larger than the spot area on the second convex lens. The first convex lens and the second convex lens can constitute a beam reduction system to reduce the light emitted by the light source, ensuring that more light is directed to the light homogenizing component for forming a projection screen, thereby ensuring that the utilization rate of the light is high. And because the first diffuser is located at the coincident focus, on the one hand, according to the principle of light beam convergence and imaging, the light at the focus (convergence imaging point) can be emitted from a point light source at any beam angle to the lens, and can be collimated into a parallel beam by the lens. Therefore, the first diffuser can be set to a larger divergence angle to diffuse the incident laser beam to a greater extent, so that the laser beam has a good homogenization effect, and the laser beam after being diffused at a large angle can still be converged into a collimated state by the second convex lens after being directed to the second convex lens.

[0067] Furthermore, the spot size of the laser beam collimated by the second convex lens is reduced, achieving beam contraction, which in turn facilitates the use of subsequent optical lenses. In this technical solution, there is no need to create a dedicated optical path location for the first diffuser. Instead, it is located between the two existing lenses, achieving the dual functions of beam contraction and speckle reduction without increasing the optical path length.

[0068] Therefore, the projection device can expand the divergence angle of the light emitted by the light source to reduce the coherence of the light without affecting the light convergence and ensuring that the light utilization rate and optical path length do not increase, thereby reducing the speckle effect of the projection device and improving the display effect of the projection screen of the projection device.

[0069] The above embodiment of the present application is illustrated by the case where the projection device includes a focusing component consisting of a first convex lens 1041 and a second convex lens 1042, a first diffuser 105, and a second diffuser 106. In an optional implementation of the projection device, the projection device may also include only any one or any two of the three structures, and the embodiment of the present application is not limited thereto. For example, the projection device may include the focusing component but not the first diffuser 105 and the second diffuser 106; or the projection device may include the focusing component and the first diffuser 105 but not the second diffuser 106; or the projection device may include the focusing component and the second diffuser 106 but not the first diffuser 105; or the projection device may include the second diffuser 106 but not the focusing component and the first diffuser 105.

[0070] Figure 5 This is a structural diagram of another projection device provided in an embodiment of the present application. Figure 5 As shown, a lens group consisting of a convex lens 1043 and a concave lens 1044 can be used to replace Figure 2 or Figure 3 The first convex lens 1041, the second convex lens 1042 and the first diffuser 105 are formed to obtain an optional structure of the projection device. The convex lens 1043 and the concave lens 1044 are arranged along the direction of the light source 20 and the light uniforming component 101 (such as Figure 5 The lens group composed of the convex lens 1043 and the concave lens 1044 is a common telescope group. The lens group has the same function as the first convex lens 1041 and the second convex lens 1042, and is also used to shrink the light beam. Figure 5 The light homogenizing component 101 in the projection device shown includes a fly-eye lens, thereby ensuring the miniaturization of the projection device. Optionally, the optical axes of the convex lens 1043, the concave lens 1044 and the fly-eye lens can be collinear. Figure 5 The structures other than the convex lens 1043 and the concave lens 1044 can all be referred to Figure 2 or Figure 4 The related introduction of the structures other than the first convex lens 1041, the second convex lens 1042 and the first diffusion sheet 105 will not be repeated in this embodiment of the application.

[0071] Figure 6 This is a structural diagram of another projection device provided in an embodiment of the present application. Figure 6 The figure shown may be a diagram of the overall appearance of the optical engine of the projection device, which may be a diagram of the overall appearance of the optical engine of the projection device of any optional structure in the above embodiments. Figure 6As shown, the projection device includes an optical engine 10, a light source 20, and a lens 30. The light source is used to emit light to the optical engine 10, and the optical engine 10 is used to modulate the incident light and then direct it toward the lens 30, which is used to project the incident light. The optical engine 10 can include the first convex lens, second convex lens, first diffuser, second diffuser, light homogenizing component, illumination lens assembly, and light valve described above in the projection device.

[0072] The term "and / or" in this application is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the objects associated before and after are in an "or" relationship. The term "at least one of A, B, and C" in this application indicates that seven relationships may exist, indicating: A exists alone, B exists alone, C exists alone, A and B exist at the same time, A and C exist at the same time, C and B exist at the same time, and A, B, and C exist at the same time. In the embodiments of the present application, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance. The term "multiple" refers to two or more, unless otherwise expressly defined.

[0073] The above description is merely an optional embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A projection device, characterized in that: The projection device includes: a light source, a light valve, and a lens, wherein the light source is used to emit light to the light valve, the light valve is used to modulate the incident light and then emit it to the lens, and the lens is used to project the incident light; The projection device further includes: a first convex lens, a first diffuser, a second convex lens, and a light uniforming component located in a light path between the light source and the light valve; the focal points of the first convex lens and the second convex lens coincide with each other, and the coincident focal points are located between the first convex lens and the second convex lens; the first diffuser is located at the focal points; The first convex lens is used to converge the light emitted by the light source to the first diffuser, the first diffuser is used to expand the divergence angle of the incident light and then direct it to the second convex lens, the second convex lens is used to direct the incident light to the light uniforming component, and the light uniforming component is used to uniformize the incident light and then direct it to the light valve. The projection device also includes: a second diffuser, the second diffuser is located between the second convex lens and the light uniforming component, and the diffusion angle of the second diffuser is smaller than the diffusion angle of the first diffuser; The light source is configured to emit laser light of at least two colors, the laser light of the at least two colors comprising: laser light with a first divergence angle and laser light with a second divergence angle, the first divergence angle being greater than the second divergence angle; the first diffuser comprising a first diffusion region and a second diffusion region, the diffusion angle of the first diffusion region being smaller than the diffusion angle of the second diffusion region; the laser light with the first divergence angle being emitted toward the first diffusion region, and the laser light with the second divergence angle being emitted toward the second diffusion region; The projection device further comprises: an illumination lens assembly located in the light path between the light uniforming component and the light valve; The lighting mirror assembly includes a third convex lens, a reflective sheet, a fourth convex lens and a total internal reflection prism. The light emitted by the light-homogenizing component passes through the third convex lens and is emitted to the reflective sheet. The reflective sheet is used to reflect the incident light to the fourth convex lens. The fourth convex lens is used to converge the incident light to the total internal reflection prism. The total internal reflection prism is used to reflect the incident light to the light valve. The light spot area on the first convex lens is larger than the light spot area on the second convex lens.

2. The projection device according to claim 1, wherein: The focal length of the first convex lens is greater than the focal length of the second convex lens.

3. The projection device according to claim 1 or 2, characterized in that: The ratio of the light spot area on the first convex lens to the light spot area on the second convex lens is in the range of 1.5 to 3.

4. The projection device according to claim 1, wherein: The diffusion angle of the first diffusion sheet ranges from 8 degrees to 16 degrees.

5. The projection device according to claim 1, wherein: The diffusion angle of the second diffusion sheet ranges from 1 degree to 6 degrees.

6. The projection device according to claim 1, wherein: The first diffusion sheet is a movable diffusion sheet, and the second diffusion sheet is fixed.

7. The projection device according to claim 1, wherein: The light uniforming component includes a fly-eye lens.

8. The projection device according to claim 7, characterized in that The fly-eye lens includes a plurality of lens units; The fly-eye lens satisfies at least one of the following requirements: The orthographic projection area of ​​the fly-eye lens on a plane perpendicular to the optical axis of the fly-eye lens ranges from 144 square millimeters to 265 square millimeters; The orthographic projection of the fly-eye lens on a plane perpendicular to the optical axis of the fly-eye lens is a rectangle, and the aspect ratio of the rectangle is in the range of 1.6 to 2; Furthermore, a maximum distance between two ends of the lens unit in a direction perpendicular to the optical axis ranges from 0.5 mm to 1.5 mm.

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