A projection device

Abstract

The utility model discloses a kind of projection equipment, comprising: light source component, for emitting light;Light transmission screen, be set to the light emission side of light source component, for making the emission light of light source component transmit light transmission screen after emission;Light collecting element, be set to the light emission side of light transmission screen, light collecting element is provided with optical surface, optical surface is used to refract when the emission light of light transmission screen transmits optical surface, make the emission light of light transmission screen converge to projection lens, the optical center of optical surface deviates the first optical axis of light source component;Projection lens, be set to the light emission side of light collecting element, for projecting the light incident to projection lens, the second optical axis of projection lens and the optical axis that passes through the optical center of optical surface is coaxial.The utility model projection equipment can satisfy the application requirement of off-axis, and can make projection equipment volume smaller.

Description

Technical Field

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

[0002] Projectors are becoming increasingly smaller. To meet the requirements of some application scenarios, projectors need an off-axis design. However, currently available off-axis projectors are relatively large and cannot simultaneously meet the dual requirements of miniaturization and off-axis design. Utility Model Content

[0003] The purpose of this invention is to provide a projection device that can meet the application requirements of off-axis projection and has a small size.

[0004] To achieve the above objectives, this utility model provides a projection device, comprising:

[0005] Light source assembly, used for emitting light;

[0006] A light-transmitting screen is disposed on the light-emitting side of the light source assembly, and is used to allow the emitted light from the light source assembly to pass through the light-transmitting screen before being emitted.

[0007] A light-concentrating element is disposed on the light-emitting side of the light-transmitting screen. The light-concentrating element is provided with an optical surface. The optical surface is used to refract the light emitted from the light-transmitting screen when it passes through the optical surface, so that the light emitted from the light-transmitting screen is focused onto the projection lens. The optical center of the optical surface is offset from the first optical axis of the light source assembly.

[0008] The projection lens is disposed on the light-emitting side of the light-concentrating element and is used to project the light incident on the projection lens. The second optical axis of the projection lens is coaxial with the optical axis passing through the optical center of the optical surface.

[0009] Optionally, the optical surface includes a central optical surface and at least one annular optical surface, the at least one annular optical surface surrounding the central optical surface, and the center of the central optical surface being the optical center.

[0010] Optionally, the focusing element is provided with at least one annular tooth, the at least one annular tooth surrounding the central optical surface, the at least one annular optical surface and the at least one annular tooth corresponding one-to-one, and any one of the at least one annular optical surfaces is disposed on the corresponding annular tooth.

[0011] Optionally, the geometric center of the focusing element is located on the first optical axis of the light source assembly.

[0012] Optionally, the light source assembly includes:

[0013] Light source, used to emit light;

[0014] A light homogenizing unit is disposed on the light-emitting side of the light source and is used to homogenize the emitted light from the light source.

[0015] Optionally, the light-diffusing section includes:

[0016] The light-transmitting cavity includes an inlet and an outlet, with the diameter gradually increasing from the inlet to the outlet. It is used to allow the emitted light from the light source to enter the light-transmitting cavity through the inlet, and after multiple reflections from the inner surface of the light-transmitting cavity, to exit through the outlet.

[0017] Optionally, it also includes:

[0018] A collimating element is disposed on the light-emitting side of the light-transmitting cavity to collimate the light emitted from the light-transmitting cavity, so that the light emitted from the collimating element is incident on the light-transmitting screen.

[0019] Alternatively, the following condition must be satisfied:

[0020] ;

[0021] Wherein, L1 represents the length of the light-emitting surface of the light source, L3 represents the length of the light-emitting port of the light-transmitting cavity, H1 represents the length of the light-transmitting cavity along its own optical axis, F1 represents the focal length of the collimating element, and d represents the preset deviation.

[0022] Optionally, it also includes:

[0023] A first polarizing element is disposed on the side of the light-transmitting screen close to the light source assembly, and is used to transmit the first polarized light in the emitted light from the light source assembly and reflect the second polarized light.

[0024] The second polarizing element is disposed on the side of the light-transmitting screen close to the projection lens, and is used to allow the first polarized light in the light emitted from the light-transmitting screen to pass through.

[0025] Optionally, it further includes: a reflective element disposed on the side of the light-collecting element near the projection lens, for reflecting the light emitted from the light-collecting element to the projection lens, wherein the second optical axis of the projection lens intersects the optical axis passing through the optical center of the optical surface on the reflective element.

[0026] As can be seen from the above technical solution, in the projection device provided by this utility model, the optical center of the optical surface of the focusing element is offset from the first optical axis of the light source assembly, so that the light passing through the light-transmitting screen is tilted after passing through the focusing element, and the light after passing through the focusing element is asymmetrical with respect to the first optical axis. The second optical axis of the projection lens is coaxial with the optical axis passing through the optical center of the optical surface of the focusing element. The light after passing through the focusing element is further projected out from the projection lens, making the light projected by the projection lens asymmetrical with respect to the second optical axis of the projection lens, thereby meeting the application requirements of off-axis projection. Furthermore, compared with the existing method of achieving off-axis projection by offsetting the entire focusing lens and the projection lens from the optical axis of the light source, this projection device achieves off-axis projection by offsetting the optical center of the optical surface of the focusing element from the first optical axis of the light source assembly, avoiding the overall offset of the focusing element, thus enabling a smaller projection device size. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 A schematic diagram of a focusing element of a projection device provided in one embodiment;

[0029] Figure 2 A schematic diagram of a light source for a projection device is provided in one embodiment;

[0030] Figure 3 A bottom view of the light-transmitting cavity of the light-monitoring section of a projection device according to one embodiment;

[0031] Figure 4 for Figure 3 A front view of the light-transmitting cavity shown;

[0032] Figure 5 for Figure 3 Side view of the light-transmitting cavity shown;

[0033] Figure 6 A schematic diagram of a collimation element for a projection device is provided in one embodiment;

[0034] Figure 7 A side view of a projection device provided in one embodiment.

[0035] The reference numerals in the accompanying drawings include:

[0036] 1-Light source, 2-Light-passing cavity, 3-Collimating element, 4-Light-transmitting screen, 5-Light-concentrating element, 6-Reflecting element, 7-Projection lens, 8-First polarizing element, 9-Second polarizing element, 10-Light ray, 21-Light inlet, 22-Light outlet, 51-Central optical surface, 52-Annular optical surface, a1-First optical axis, a2-Second optical axis, a3-Optical center of the optical surface. Detailed Implementation

[0037] To enable those skilled in the art to better understand the technical solutions of this utility model, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

[0038] This embodiment provides a projection device, including:

[0039] Light source assembly, used for emitting light;

[0040] A light-transmitting screen is disposed on the light-emitting side of the light source assembly, and is used to allow the emitted light from the light source assembly to pass through the light-transmitting screen before being emitted.

[0041] A light-concentrating element is disposed on the light-emitting side of the light-transmitting screen. The light-concentrating element is provided with an optical surface. The optical surface is used to refract the light emitted from the light-transmitting screen when it passes through the optical surface, so that the light emitted from the light-transmitting screen is focused onto the projection lens. The optical center of the optical surface is offset from the first optical axis of the light source assembly.

[0042] The projection lens is disposed on the light-emitting side of the light-concentrating element and is used to project the light incident on the projection lens. The second optical axis of the projection lens is coaxial with the optical axis passing through the optical center of the optical surface.

[0043] The light emitted from the light source component is incident on the transparent screen and exits after passing through it. The emitted light from the transparent screen is then incident on the focusing element, and refracted as it passes through the optical surface of the focusing element, causing the emitted light to converge onto the projection lens. The optical axis of the light source component is the first optical axis, and the optical axis of the projection lens is the second optical axis. The optical center of the optical surface of the focusing element is offset from the first optical axis of the light source component; that is, the optical axis passing through the optical center of the optical surface of the focusing element is not coaxial with the first optical axis of the light source component.

[0044] In this embodiment of the projection device, the optical center of the optical surface of the focusing element is offset from the first optical axis of the light source assembly. This causes the light passing through the screen to be tilted after passing through the focusing element, making the light asymmetrical relative to the first optical axis. The second optical axis of the projection lens is coaxial with the optical axis passing through the optical center of the focusing element's optical surface. The light passing through the focusing element is further projected from the projection lens, making the light projected by the projection lens asymmetrical relative to its second optical axis, thus meeting the requirements for off-axis applications. Furthermore, compared to existing methods that achieve off-axis by offsetting the entire focusing lens and the projection lens from the light source's optical axis, this projection device achieves off-axis by offsetting the optical center of the focusing element's optical surface from the first optical axis of the light source assembly, avoiding the overall offset of the focusing element. Therefore, the projection device can be made smaller.

[0045] If there is no reflective element between the condenser element and the projection lens, then the coaxiality of the second optical axis of the projection lens with the optical axis passing through the optical center of the optical surface means that the second optical axis of the projection lens and the optical axis passing through the optical center of the optical surface can coincide. If there is a reflective element between the condenser element and the projection lens, and the light emitted from the condenser element is reflected by the reflective element to the projection lens, then the coaxiality of the second optical axis of the projection lens with the optical axis passing through the optical center of the optical surface means that the second optical axis of the projection lens and the optical axis passing through the optical center of the optical surface can intersect at the reflective element.

[0046] By using a focusing element to converge the light emitted from a transparent screen and direct it onto the projection lens, the projection device can improve light utilization. In some embodiments, the optical surface of the focusing element includes a central optical surface and at least one annular optical surface, the at least one annular optical surface surrounding the central optical surface, the center of the central optical surface being the optical center. When the light emitted from the transparent screen passes through the central optical surface and the at least one annular optical surface of the focusing element, it is refracted, causing the light emitted from the transparent screen to converge and then be directed onto the projection lens. For example, see [reference needed]. Figure 1 , Figure 1 This is a schematic diagram of a focusing element of a projection device provided in one embodiment, such as... Figure 1 As shown, the focusing element 5 includes a central optical surface 51 and multiple annular optical surfaces 52, which surround the central optical surface 51 and are arranged in sequence along the radial direction.

[0047] In some embodiments, the focusing element 5 is provided with at least one annular toothed portion surrounding the central optical surface 51. At least one annular optical surface 52 corresponds one-to-one with the at least one annular toothed portion, and any one of the at least one annular optical surfaces 52 is disposed on the corresponding annular toothed portion. By providing at least one annular toothed portion to form the at least one annular optical surface 52, the central optical surface 51 and the at least one annular optical surface 52 are combined, allowing the emitted light from the light-transmitting screen to be refracted upon transmission, converging the emitted light from the light-transmitting screen and incident on the projection lens. Compared to using a lens with a single curved side surface, the focusing element 5 of this embodiment has a smaller thickness along the optical axis, which helps to reduce the size of the projection device. The focusing element 5 can be a Fresnel lens.

[0048] In this embodiment, the offset distance from the optical center of the optical surface of the focusing element 5 to the first optical axis of the light source assembly is not limited. In practical applications, it can be set according to the off-axis requirements of the light projected by the projection device. In some embodiments, the geometric center of the focusing element 5 is located on the first optical axis of the light source assembly. This makes it easier to determine and adjust the position of the focusing element 5 when assembling it in the projection device.

[0049] In some embodiments, the light source assembly includes: a light source for emitting light; and a light homogenizing unit disposed on the light-emitting side of the light source for homogenizing the emitted light. The emitted light from the light source passes through the light homogenizing unit, which makes the light intensity distribution uniform.

[0050] In some embodiments, the light source 1 includes a light-emitting surface from which light is emitted. Compared to using a point light source, the light-emitting surface has a larger area, which, when applied to a projection device, helps to improve the brightness uniformity of the projected image. The light source 1 can be an integrated high-power light source. For example, see [reference needed]. Figure 2 , Figure 2 A schematic diagram of a light source for a projection device is provided as an embodiment, such as... Figure 2 As shown, the light-emitting surface of light source 1 is square. Light source 1 may include a light-emitting diode (LED). Light source 1 may employ, but is not limited to, powder application or powder spraying processes.

[0051] In this embodiment, the structure of the light homogenizing section is not limited, as long as it can homogenize the emitted light from the light source 1. In some embodiments, the light homogenizing section includes a light-transmitting cavity, comprising an inlet and an outlet, with the diameter gradually increasing from the inlet to the outlet. This cavity allows the emitted light from the light source 1 to enter the light-transmitting cavity through the inlet, undergo multiple reflections from the inner surface of the cavity, and then exit through the outlet. The emitted light from the light source 1 enters the light-transmitting cavity through the inlet, and during its propagation within the cavity, undergoes multiple reflections from the inner surface before exiting through the outlet. This ensures a uniform intensity distribution of the emitted light, thereby enabling the light-transmitting cavity to homogenize the light and reduce the light emission angle.

[0052] In some embodiments, the shape of the light inlet is consistent with the shape of the light-emitting surface of the light source 1. For example, the light-emitting surface of the light source 1 is square, and the light inlet of the light-transmitting cavity is square. For example, see [reference needed]. Figures 3 to 5 , Figure 3 This is a bottom view of the light-transmitting cavity of the light-monitoring section of a projection device according to one embodiment. Figure 4 for Figure 3 The front view of the light-transmitting cavity shown. Figure 5 for Figure 3 The side view of the light-transmitting cavity is shown. Figures 3 to 5 As shown, the light inlet 21 of the light-transmitting cavity 2 is square, and the light outlet 22 is square. Figures 3 to 5 The light-transmitting cavity 2 shown can be called a rectangular uniform light cone.

[0053] In some embodiments, the projection device further includes a collimating element disposed on the light-emitting side of the light source assembly, used to collimate the emitted light from the light source assembly, so that the emitted light from the collimating element is incident on the transparent screen. The collimating element collimates the emitted light from the light source assembly, reducing the emission angle of the emitted light and improving light utilization. In some embodiments, the collimating element is disposed on the light-emitting side of the light-transmitting cavity 2, used to collimate the emitted light from the light-transmitting cavity 2, so that the emitted light from the collimating element is incident on the transparent screen. In some embodiments, the collimating element includes a Fresnel lens. A Fresnel lens has a small length along the optical axis, which can reduce the size of the projection device. For example, see [reference needed]. Figure 6 , Figure 6 This is a schematic diagram of a collimation element of a projection device according to one embodiment, such as... Figure 6 As shown, the collimating element 3 is provided with a plurality of rings arranged in sequence, the plurality of rings being concentrically arranged to form a Fresnel pattern.

[0054] In some implementations, the projection device satisfies the following condition:

[0055] ;

[0056] Wherein, L1 represents the length of the emitting surface of the light source, L3 represents the length of the light exit port of the light-transmitting cavity, H1 represents the length of the light-transmitting cavity along its own optical axis, F1 represents the focal length of the collimating element, and d represents the preset deviation. The collimating element 3 and the light-transmitting cavity 2 satisfy the above relationship, achieving high light uniformity and light utilization. For example, the preset deviation d ranges from 5 to 15 mm, and can be set to 10 mm.

[0057] In an embodiment where the light source assembly includes a light homogenizing section and the projection device includes a collimating element, the emission angle of the emitted light from the light source 1 after passing through the light homogenizing section and the collimating element 3 is less than 12°.

[0058] In some embodiments, the light-transmitting screen 4 can be a liquid crystal display (LCD) screen, and the light-transmitting screen 4 can employ a liquid crystal display chip. In some embodiments, the projection device further includes: a first polarizing element disposed on the side of the light-transmitting screen 4 near the light source assembly, for transmitting first polarized light in the emitted light from the light source assembly and reflecting second polarized light; and a second polarizing element disposed on the side of the light-transmitting screen 4 near the projection lens, for allowing the first polarized light in the emitted light from the light-transmitting screen 4 to pass through.

[0059] In some embodiments, the projection device further includes a reflective element disposed on the side of the focusing element 5 near the projection lens, for reflecting the emitted light from the focusing element 5 to the projection lens. In some embodiments, the second optical axis of the projection lens intersects the optical axis passing through the optical center of the optical surface on the reflective element; that is, the intersection of the second optical axis of the projection lens and the optical axis passing through the optical center of the optical surface is located on the reflective element. In some embodiments, the optical axis passing through the optical center of the optical surface of the focusing element 5 and the second optical axis of the projection lens are located on the same plane, and their intersection is located on the reflective element. The reflective element may be, but is not limited to, a mirror.

[0060] For example, refer to Figure 7 , Figure 7 A side view of a projection device provided in one embodiment, such as Figure 7As shown, in this projection device, a light source 1, a light-transmitting cavity 2, a collimating element 3, a light-transmitting screen 4, and a focusing element 5 are arranged sequentially along the first optical axis a1. A reflecting element 6 is disposed between the focusing element 5 and the projection lens 7. The optical center a3 of the optical surface of the focusing element 5 is offset from the first optical axis a1. A first polarizing element 8 and a second polarizing element 9 are respectively disposed on both sides of the light-transmitting screen 4, serving as a polarizer and an analyzer, respectively. The light 10 emitted by the light source 1 passes sequentially through the light-transmitting cavity 2, the collimating element 3, the light-transmitting screen 4, the focusing element 5, and the reflecting element 6 before entering the projection lens 7. The second optical axis a2 of the projection lens 7 intersects the optical axis passing through the optical center a3 of the optical surface of the focusing element 5 at the reflecting element 6.

[0061] In a specific example, the emitting surface of light source 1 is square, with a length L1 of 12-16 mm and a width W1 of 8-12 mm. The power of light source 1 is 130-170 W, and the half-intensity angle of light source 1 is 60°-65°.

[0062] The light inlet 21 of the light-passing cavity 2 is square, with a length L2 of 13-17 mm and a width W2 of 8-12 mm. The distance between the light inlet 21 of the light-passing cavity 2 and the emitting surface of the light source 1 is less than 1 mm. The light outlet 22 of the light-passing cavity 2 has a length L3 of 100-110 mm and a width W3 of 53-57 mm. The total length H1 of the light-passing cavity 2 along its own optical axis is 65-80 mm, and the wall thickness of the light-passing cavity 2 is 0.3-0.5 mm.

[0063] The focal length F1 of the collimating element 3 is 90-110mm. The cross-section of the collimating element 3 is square, with a length L4 of 105-115mm and a width W4 of 60-70mm. The distance between the collimating element 3 and the light exit port 22 of the light-transmitting cavity 2 is less than 0.5mm. Combining the above design of the light-transmitting cavity 2 and the limitation of the emitting surface area of ​​the light source 1, the exit angle of the light emitted from the light source 1 through the light-transmitting cavity 2 and the collimating element 3 is less than 12°, so that the incident angle of the light incident on the light-transmitting screen 4 is less than 12°.

[0064] The distance between the collimating element 3 and the light-transmitting screen 4 is 10-13 mm, the distance between the light-transmitting screen 4 and the condensing element 5 is 8-12 mm, and the distance between the condensing element 5 and the projection lens 7 is 95-115 mm. The center of the projection lens 7 and the optical center a3 of the optical surface of the condensing element 5 are located on the same horizontal plane. The reflecting element 6 is located between the condensing element 5 and the projection lens 7, and the optical center of the optical surface of the condensing element 5 intersects the center of the projection lens 7 horizontally on the reflecting surface of the reflecting element 6.

[0065] The focal length F2 of the condenser element 5 is 115-125mm. The cross-section of the condenser element 5 is square, with a length L5 of 105-115mm and a width W5 of 60-70mm. Its thread center (i.e., optical center) is 20-30mm above the center of the lens.

[0066] The light-transmitting screen 4 is a 4.45-5 inch LCD screen with a resolution of 1920*1080P. Two polarizers are attached to the screen, serving as a polarizer and an analyzer respectively. The two polarizers can be placed separately on the screen. The polarizer can use a reflective brightness enhancement film + IPS light film and can be placed between the collimating element 3 and the LCD screen. The analyzer can be placed between the LCD screen and the focusing element 5.

[0067] This embodiment of the projection device optimizes the light source area, the size of the uniform light cone-shaped rod, the focal length of the alignment lens and the condenser lens, and the distance between various optical elements, so that the incident angle of the light incident on the transparent screen is within 12°. This achieves an off-axis projection optical path with high luminous efficiency and high uniformity, reduces heat accumulation on the transparent screen, and realizes high power output of the light source.

[0068] The projection device provided by this utility model has been described in detail above. Specific examples have been used to illustrate the principle and implementation of this utility model. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core idea of ​​this utility model. It should be noted that those skilled in the art can make several improvements and modifications to this utility model without departing from the principle of this utility model, and these improvements and modifications also fall within the protection scope of the claims of this utility model.

Claims

1. A projection device, characterized in that, include: Light source assembly, used for emitting light; A light-transmitting screen is disposed on the light-emitting side of the light source assembly, and is used to allow the emitted light from the light source assembly to pass through the light-transmitting screen before being emitted. A light-concentrating element is disposed on the light-emitting side of the light-transmitting screen. The light-concentrating element is provided with an optical surface. The optical surface is used to refract the light emitted from the light-transmitting screen when it passes through the optical surface, so that the light emitted from the light-transmitting screen is focused onto the projection lens. The optical center of the optical surface is offset from the first optical axis of the light source assembly. The projection lens is disposed on the light-emitting side of the light-concentrating element and is used to project the light incident on the projection lens. The second optical axis of the projection lens is coaxial with the optical axis passing through the optical center of the optical surface.

2. The projection device according to claim 1, characterized in that, The optical surface includes a central optical surface and at least one annular optical surface, the at least one annular optical surface surrounding the central optical surface, and the center of the central optical surface is the optical center.

3. The projection device according to claim 2, characterized in that, The focusing element is provided with at least one annular toothed portion, the at least one annular toothed portion surrounds the central optical surface, the at least one annular optical surface and the at least one annular toothed portion correspond one-to-one, and any one of the at least one annular optical surfaces is disposed on the corresponding annular toothed portion.

4. The projection device according to claim 1, characterized in that, The geometric center of the focusing element is located on the first optical axis of the light source assembly.

5. The projection device according to claim 1, characterized in that, The light source assembly includes: Light source, used to emit light; A light homogenizing unit is disposed on the light-emitting side of the light source and is used to homogenize the emitted light from the light source.

6. The projection device according to claim 5, characterized in that, The light-diffusing section includes: The light-transmitting cavity includes an inlet and an outlet, with the diameter gradually increasing from the inlet to the outlet. It is used to allow the emitted light from the light source to enter the light-transmitting cavity through the inlet, and after multiple reflections from the inner surface of the light-transmitting cavity, to exit through the outlet.

7. The projection device according to claim 6, characterized in that, Also includes: A collimating element is disposed on the light-emitting side of the light-transmitting cavity to collimate the light emitted from the light-transmitting cavity, so that the light emitted from the collimating element is incident on the light-transmitting screen.

8. The projection device according to claim 7, characterized in that, The following conditions must be met: ； Wherein, L1 represents the length of the light-emitting surface of the light source, L3 represents the length of the light-emitting port of the light-transmitting cavity, H1 represents the length of the light-transmitting cavity along its own optical axis, F1 represents the focal length of the collimating element, and d represents the preset deviation.

9. The projection device according to any one of claims 1 to 8, characterized in that, Also includes: A first polarizing element is disposed on the side of the light-transmitting screen close to the light source assembly, and is used to transmit the first polarized light in the emitted light from the light source assembly and reflect the second polarized light. The second polarizing element is disposed on the side of the light-transmitting screen close to the projection lens, and is used to allow the first polarized light in the light emitted from the light-transmitting screen to pass through.

10. The projection device according to any one of claims 1 to 8, characterized in that, Also includes: A reflective element is disposed on the side of the light-collecting element near the projection lens, for reflecting the light emitted from the light-collecting element to the projection lens, wherein the second optical axis of the projection lens intersects the optical axis passing through the optical center of the optical surface on the reflective element.

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