Projection device and optical device for a projection lamp

Abstract

Projection device, characterized in that it comprises: a light source assembly, wherein the light source assembly comprises at least one luminaire element designed to emit incoherent light; a light collecting assembly, wherein the light collecting assembly comprises a reflective light collector, wherein the reflective light collector has an inner reflective surface, wherein the inner reflective surface is configured to reflect the light emitted by the luminaire and to focus it onto a predetermined beam path, wherein the at least one luminaire is arranged inside the reflective light collector; a display module, wherein the display module is configured to carry and display a static or dynamic image, wherein the display module is arranged in the predetermined beam path of the light-collecting assembly such that the light treated by the light-collecting assembly falls onto the display module; an imaging assembly, wherein the imaging assembly is arranged on a side of the display module facing away from the light-collecting assembly and is configured to project the image displayed on the display module onto a projection surface to form a projection image, wherein the imaging assembly comprises at least one lens element; wherein the projection ratio of the projection device is limited to a value greater than or equal to 0.2 and less than or equal to 1.0, wherein the projection ratio is a ratio of a projection distance to a horizontal width of the projection image, wherein the projection distance is a straight-line distance from a light-exit side of the projection device to the projection surface, and wherein the projection ratio can be configured by adjusting the focal length of the imaging assembly or the size of the display module.

Description

Technical field

[0001] The present utility model relates to the field of projection technology, in particular a projection device and an optical device for a projection lamp. Background technology

[0002] In existing projection technology, a combination of several lens elements is typically used to shape the light from a light source and to create the image, enabling the display of a large image from a short distance (i.e., a small projection ratio). However, with conventional solutions, significant technical limitations often arise when the projection ratio is reduced below 1.0: On the one hand, it is difficult to simultaneously correct field curvature and distortion with a combination of several spherical lenses, resulting in blurred or distorted image edges; on the other hand, increasing the light source power to boost brightness increases heat generation in the system, which can lead to thermal damage to the film or the display chip, and the complex beam path structure also limits the compact design of the overall device.

[0003] Furthermore, most existing short-throw projection systems use coaxial transmissive light collection. The utilization rate of the light emitted by the light source is limited. In the pursuit of high brightness and uniformity, it is necessary to increase the lens aperture or the number of light sources, which further increases costs and bulk. Content of the utility model

[0004] A main objective of the present utility model is to provide a projection device that aims to improve the applicability of the projection device.

[0005] To solve this problem, the present utility model proposes a projection device comprising: a light source assembly, wherein the light source assembly comprises at least one luminaire element designed to emit incoherent light; a light collecting assembly, wherein the light collecting assembly comprises a reflective light collector, wherein the reflective light collector has an inner reflective surface, wherein the inner reflective surface is configured to reflect the light emitted by the luminaire and to focus it onto a predetermined beam path, wherein the at least one luminaire is arranged inside the reflective light collector; a display module, wherein the display module is configured to carry and display a static or dynamic image, wherein the display module is arranged in the predetermined beam path of the light-collecting assembly such that the light treated by the light-collecting assembly falls onto the display module; an imaging assembly, wherein the imaging assembly is arranged on a side of the display module facing away from the light-collecting assembly and is configured to project the image displayed on the display module onto a projection surface to form a projection image, wherein the imaging assembly comprises at least one lens element; wherein a projection ratio of the projection device is limited to a value greater than or equal to 0.2 and less than or equal to 1.0, wherein the projection ratio is a ratio of a projection distance to a horizontal width of the projection image, wherein the projection distance is a straight-line distance from a light-exit side of the projection device to the projection surface, and wherein the projection ratio can be configured by setting a focal length of the imaging assembly or a size of the display module.

[0006] Optionally, the inner reflective surface of the reflecting light collector is paraboloid-shaped.

[0007] Optionally, the light-collecting assembly further comprises at least one Fresnel lens, wherein the Fresnel lens is mounted on a light-exit side of the reflecting light collector, and wherein the Fresnel lens is arranged between the display module and the reflecting light collector.

[0008] Optionally, the distance between the Fresnel lens and the display module can be greater than 3 mm and less than 12 mm.

[0009] Optionally, one side of the Fresnel lens facing the light element is a smooth surface, and one side of the Fresnel lens facing the display module is provided with several concentric groove structures at intervals from the center to a circumferential side.

[0010] Optionally, the distance between the Fresnel lens and the light element can be greater than 8 mm and less than 40 mm.

[0011] Optionally, the projection device further comprises a reflecting mirror, wherein the reflecting mirror is arranged between the light-collecting assembly and the display module; the predetermined beam path comprises a first beam path from the luminaire element to the reflecting mirror and a second beam path from the reflecting mirror to the display module, wherein an angle is formed between the first beam path and the second beam path.

[0012] Optionally, the angle between the first beam path and the second beam path can be a right angle.

[0013] Optionally, the reflecting mirror can be a triangular prism or a plane mirror.

[0014] Optionally, the light-collecting assembly further comprises at least one Fresnel lens, wherein the Fresnel lens is mounted on a light-exit side of the reflecting mirror, and wherein the Fresnel lens is arranged between the display module and the reflecting mirror.

[0015] Optionally, the light source assembly is further equipped with at least one light collecting lens element, wherein the light collecting lens element is arranged on a light exit side of the luminaire element.

[0016] Optionally, the imaging assembly includes at least three aspherical lenses with positive refractive power and at least one aspherical lens with negative refractive power, arranged sequentially along a projection direction of the display module.

[0017] Optionally, the imaging assembly further includes an aperture, wherein the aperture is arranged between the lens elements of the imaging assembly to limit a beam aperture.

[0018] Optionally, the display module includes a circular or elliptical effective display area, wherein the effective display area is arranged coaxially with the predetermined beam path; wherein a cross-sectional shape of the beam path at a light exit surface of the reflecting light collector is adapted to the shape of the effective display area.

[0019] Optionally, several lighting elements are provided, wherein the multiple lighting elements are arranged at intervals around an inner center point of the reflecting light collector, with the lighting elements forming an angle with a base of the reflecting light collector.

[0020] Optionally, the projection device further comprises a heat dissipation device, wherein the heat dissipation device has an air duct, wherein the display module is arranged in the air duct, wherein a fan is arranged in the air duct, wherein the fan is configured to direct an airflow from a surface of the display module and to dissipate heat from the display module.

[0021] Optionally, the lens element satisfies the following conditions: f / EPD<2.0; TTL / BFL<8.4, where f denotes an effective focal length of the lens element, EPD denotes an entrance pupil diameter of the lens element, TTL denotes a total optical length of the lens element, and BFL denotes a rear focal length of the lens element.

[0022] Optionally, the display module is designed to carry and display a static or dynamic image of a Milky Way starry sky, an image of celestial bodies, or an image of a natural landscape.

[0023] The present utility model further provides an optical device for a projection lamp. The optical device for a projection lamp comprises: a light source assembly, wherein the light source assembly comprises at least one luminaire element designed to emit incoherent light; a light collecting assembly, wherein the light collecting assembly comprises a reflective light collector, wherein the reflective light collector has an inner reflective surface, wherein the inner reflective surface is configured to reflect the light emitted by the luminaire and to focus it onto a predetermined beam path, wherein the at least one luminaire is arranged inside the reflective light collector; a display module, wherein the display module is configured to carry and display a static or dynamic image, wherein the display module is arranged in the predetermined beam path of the light-collecting assembly such that the light treated by the light-collecting assembly falls onto the display module; an imaging assembly, wherein the imaging assembly is arranged on a side of the display module facing away from the light-collecting assembly and is configured to project the image displayed on the display module onto a projection surface to form a projection image, wherein the imaging assembly comprises an imaging lens, focusing lens and wide-angle lens arranged successively along a projection direction of the display module, wherein the focusing lens comprises a fifth lens element and a sixth lens element, and wherein the sixth lens element is arranged between the fifth lens element and the imaging lens; wherein the fifth lens element has a positive refractive power, an object side of the fifth lens element is convex and an image side of the fifth lens element is concave; wherein the sixth lens element has a negative refractive power, an object side of the sixth lens element is convex and an image side of the sixth lens element is concave; wherein a projection ratio of the optical device is limited to a value greater than or equal to 0.2 and less than or equal to 1.0, wherein the projection ratio is a ratio of a projection distance to a horizontal width of the projection image, wherein the projection distance is a straight-line distance from a light exit side of the projection device to the projection surface, and wherein the projection ratio can be configured by adjusting the focal length of the imaging assembly or the size of the display module.

[0024] Optionally, the curvature of the object side of the fifth lens element is equal to the curvature of the image side of the sixth lens element, and the object side of the fifth lens element is cemented to the image side of the sixth lens element.

[0025] The present utility model provides a projection device comprising a light source assembly, a light-collecting assembly, a display module, and an imaging assembly. The light source assembly comprises at least one luminaire element designed to emit incoherent light; the light-collecting assembly comprises a reflective light collector with an internal reflective surface, wherein the luminaire element is arranged within the reflective light collector such that light is reflected from the internal reflective surface and focused onto a predetermined beam path; the display module is arranged in the predetermined beam path and is configured to carry and display an image; the imaging assembly is arranged on a light-exit side of the display module and comprises at least one lens element configured to project the image onto a projection surface.Simultaneously, the projection ratio of the projection device is limited to a value greater than or equal to 0.2 and less than or equal to 1.0 and can be flexibly configured by adjusting the focal length of the imaging assembly or the size of the display module. Due to the aforementioned structure, the present utility model places the luminaire inside the reflective light collector and utilizes its internal reflective surface to achieve efficient light collection and uniform focusing, thereby significantly improving light energy utilization and reducing the volume of the light collector. The display module is located in the uniform beam path formed by the light collector assembly, ensuring uniform illumination.The imaging assembly, in conjunction with the setting of the small projection ratio from 0.2 to 1.0, enables the projection device to project large-format, high-resolution images at extremely short distances, thus meeting the requirements for use in space-constrained scenarios. This significantly optimizes the projection device in terms of light output, uniformity, miniaturization, and short-throw projection capability. Description of the drawings

[0026] To more clearly explain the technical solutions in the embodiments of the present utility model or in the prior art, the drawings required for describing the embodiments or the prior art are briefly presented below. Obviously, the drawings in the following description represent only some embodiments of the present utility model. A person skilled in the art can obtain further drawings based on the structures shown in these drawings without any inventive effort. Fig. Figure 1 shows a schematic cross-sectional structural view of an embodiment of the projection device of the present utility model, viewed from an angle; Fig. Figure 2 shows a schematic cross-sectional structural view of an embodiment of the projection device of the present utility model, viewed from a different angle; Fig. Figure 3 shows a schematic cross-sectional structural view of an embodiment of the projection device of the present utility model; Fig. Figure 4 shows a schematic representation of the beam path principle of an embodiment of the projection device of the present utility model; Fig. Figure 5 shows a schematic cross-sectional structure view of a further embodiment of the projection device of the present utility model, viewed from an angle; Fig. Figure 6 shows a schematic cross-sectional structure view of another embodiment of the projection device of the present utility model, viewed from a different angle; Fig. Figure 7 shows a schematic cross-sectional structure view of a further embodiment of the projection device of the present utility model; Fig. Figure 8 shows a schematic cross-sectional structure view of a further embodiment of the projection device of the present utility model, viewed from an angle; Fig. Figure 9 shows a schematic cross-sectional structure view of a further embodiment of the projection device of the present utility model, viewed from a different angle; Fig. Figure 10 shows a schematic cross-sectional structure view of a further embodiment of the projection device of the present utility model; Fig. Figure 11 shows a schematic representation of the beam path principle of a further embodiment of the projection device of the present utility model; Fig. Figure 12 shows a schematic representation of the projection ratio of the projection device; Fig. Figure 13 shows a schematic representation of the projection ratio of the projection device; Fig. Figure 14 shows a schematic structural view of the display module in an angled view; Fig. Figure 15 shows a schematic structural view of the Fresnel lens in an angled view; Fig. Figure 16 shows a schematic structural view of a practical application example of the projection device; Fig. Figure 17 shows a schematic structural view of another practical application example of the projection device; Fig. Figure 18 shows a schematic structural view of yet another practical application example of the projection device; Fig. Figure 19 shows a schematic structural view of another practical application example of the projection device; Fig. Figure 20 shows a schematic cross-sectional structure view of the illustration assembly; Fig. Figure 21 shows a schematic representation of the beam path of the imaging assembly. Reference symbol list 10 Light source assembly 11 lighting element 12 light-collecting lens element 21 reflective light collectors 211 inner reflective surface 22 predetermined beam path 221 first beam path 222 second beam path 23 Fresnel lens 30 Display module 31 effective display area 41 Projection image 42 first lens element 43 second lens element 44 third lens element 45 fourth lens element 46 aperture 47 Imaging lens 48 Focusing lens 481 fifth lens element 482 sixth lens element 49 wide-angle lens 50 reflective mirrors 60 Heat dissipation device 63 Thermal insulation lens Detailed descriptions

[0027] The technical solutions in the embodiments of this utility model are described clearly and completely below with reference to the drawings of those embodiments. Obviously, the described embodiments represent only a subset of the embodiments of this utility model, not all of them. Based on the embodiments of this utility model, all other embodiments that a person skilled in the art would obtain without inventive effort fall within the scope of protection of this utility model.

[0028] It should be noted that if the embodiments of this utility model include directional terms (such as up, down, left, right, front, back, etc.), these directional terms serve only to explain the relative positioning, movement, etc., of the components in a specific orientation (as shown in the drawings). If the specific orientation changes, the directional terms change accordingly.

[0029] Furthermore, in the embodiments of this utility model, terms such as "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying their relative importance or as implicitly indicating the number of technical features mentioned. Thus, features designated as "first" or "second" may expressly or implicitly include at least one such feature. The meaning of "and / or" throughout the text encompasses three parallel solutions. In the example of "A and / or B," it includes solution A, or solution B, or a solution in which A and B are satisfied simultaneously. Moreover, the technical solutions can be combined between the various embodiments, but only on the basis of the capabilities of a person skilled in the art to implement them.If the combination of technical solutions is contradictory or not feasible, it is to be assumed that such a combination of technical solutions does not exist and does not fall within the claimed scope of protection of the present utility model.

[0030] The present utility model provides a projection device and an optical device for a projection lamp.

[0031] In one embodiment of the present utility model, as shown in Figs. 1 to 19, the projection device comprises: a light source assembly 10, wherein the light source assembly 10 comprises at least one luminaire element 11 designed to emit incoherent light; a light collecting assembly, wherein the light collecting assembly comprises a reflective light collector 21, wherein the reflective light collector 21 has an inner reflective surface 211, wherein the inner reflective surface 211 is configured to reflect the light emitted by the luminaire 11 and to focus it onto a predetermined beam path 22, wherein the at least one luminaire 11 is arranged inside the reflective light collector 21; a display module 30, wherein the display module 30 is configured to carry and display a static or dynamic image, wherein the display module 30 is arranged in the predetermined beam path 22 of the light-collecting assembly, such that the light treated by the light-collecting assembly falls on the display module 30; an imaging assembly, wherein the imaging assembly is arranged on a side of the display module 30 facing away from the light-collecting assembly and is configured to project the image displayed on the display module 30 onto a projection surface to form a projection image 41, wherein the imaging assembly comprises at least one lens element; wherein a projection ratio of the projection device is limited to a value greater than or equal to 0.2 and less than or equal to 1.0, wherein the projection ratio is a ratio of a projection distance to a horizontal width of the projection image 41, wherein the projection distance is a straight-line distance from a light-exit side of the projection device to the projection surface, and wherein the projection ratio can be configured by setting a focal length of the imaging assembly or a size of the display module 30.

[0032] In this embodiment, during assembly, the luminaire element 11 is attached to the inner base or side wall of the reflective light collector 21, so that the light emitted by it first strikes the inner reflective surface 211; the reflective light collector 21 is fixed at the front end of the beam path by means of a holder or a housing, its inner reflective surface 211 reflecting the light emitted by the luminaire element 11 and focusing it into a substantially parallel beam of light that exits along the predetermined beam path 22; the display module 30 is mounted on the light-exit side of the light-collecting assembly via a groove or a frame, so that the uniform beam of light processed by the light-collecting assembly falls perpendicularly onto the pattern area of ​​the display module 30;The imaging assembly is connected to the light-exit side of the display module 30 via a tube, its lens elements arranged coaxially with the display module 30 to ensure that the pattern light enters the imaging beam path precisely. Functionally, the illuminating element 11, acting as the light source, generates the basic illumination light; the reflective light collector 21 uses its internal reflective surface 211 to efficiently collect and shape the light, transforming the initially divergent light beam into a uniformly directed illumination spot; the internal arrangement of the illuminating element 11 within the light collector significantly improves the light energy utilization rate; the display module 30 carries a predefined pattern and, after uniform illumination, emits a light beam carrying image information.The imaging assembly focuses and magnifies this beam of light, ultimately forming a clear, magnified image on the projection surface. By limiting the projection ratio to the range of 0.2 to 1.0, the projection device can project a large-format image at an extremely short projection distance and adapt to spatially restricted scenarios. Simultaneously, the projection ratio can be flexibly changed by adjusting the focal length of the imaging assembly or by replacing the display module 30 with a different size, allowing the same platform to be adapted to various projection specifications.

[0033] It should be explained that the projection ratio (the ratio of D1 to D2 in Fig. 12) denotes the ratio of the projection distance to the horizontal width of the projected image 41, where the projection distance is the straight line distance from the outermost light-emitting surface of the projection device to the projection surface. The smaller the projection ratio, the wider the image obtainable at the same projection distance, indicating a greater short-throw projection capability. The illuminating element 11 is an incoherent light source, such as an LED or a halogen lamp. The light it emits is incoherent, thus avoiding the speckle problem associated with laser light sources. The inner reflective surface 211 of the reflecting light collector 21 can be a parabolic or a freeform surface.Their core function is to efficiently focus the light emitted by the light source and direct it towards the display module 30. The display module 30 can be a film, an LCD screen, or another image carrier; the image on it can be a static pattern (such as a starry sky, celestial bodies, or a natural landscape) or a dynamic image.

[0034] Furthermore, the projection ratio can be configured in two specific ways: First, by adjusting the focal length of the imaging assembly. With a fixed size of the display module 30, decreasing the focal length of the imaging assembly enlarges the projected image, thereby decreasing the projection ratio accordingly; increasing the focal length reduces the image and increases the projection ratio. Second, by changing the size of the effective display area 31 of the display module 30. With a fixed focal length of the imaging assembly, using a display module 30 with a larger display area increases the horizontal width of the projected image, thereby decreasing the projection ratio; conversely, a smaller display area increases the projection ratio. These two methods can be applied individually or in combination to achieve different projection effects.

[0035] The structure described above places the luminaire element 11 inside the reflective light collector 21 and utilizes the internal reflective surface 211 to achieve efficient light collection and uniform illumination. Together with the display module 30 arranged in the uniform beam path and the imaging assembly with short-throw projection capability, a high-brightness, high-resolution large-screen projection is achieved within the projection ratio range of 0.2 to 1.0. The structure is compact, light-efficient, and highly adaptable, making it suitable for various application scenarios such as home entertainment, commercial displays, and ambient lighting.

[0036] The technical solution of the present utility model provides a projection device comprising a light source assembly 10, a light-collecting assembly, a display module 30, and an imaging assembly. The light source assembly 10 comprises at least one luminaire 11 designed to emit incoherent light; the light-collecting assembly comprises a reflective light collector 21 with an internal reflective surface 211, wherein the luminaire 11 is arranged within the reflective light collector 21 such that light is reflected from the internal reflective surface 211 and focused onto a predetermined beam path 22; the display module 30 is arranged in the predetermined beam path 22 and is configured to carry and display an image.The imaging assembly is arranged on a light-exit side of the display module 30 and comprises at least one lens element configured to project the image onto a projection surface. Simultaneously, the projection ratio of the projection device is limited to a value greater than or equal to 0.2 and less than or equal to 1.0 and is flexibly configurable by adjusting the focal length of the imaging assembly or the size of the display module 30. By virtue of the above structure, the present utility model places the luminaire element 11 inside the reflective light collector 21 and utilizes its inner reflective surface 211 to achieve efficient light collection and uniform focusing, thereby significantly improving light energy utilization and reducing the volume of the light collector.The display module 30 is located in the uniform beam path formed by the light-collecting assembly, which ensures uniform illumination; and the imaging assembly, in conjunction with the setting of the small projection ratio from 0.2 to 1.0, enables the projection device to project large-format, high-resolution images at extremely short distances, thus meeting the usage requirements in space-constrained scenarios. This significantly optimizes the projection device in terms of light output, uniformity, miniaturization, and short-throw projection capability.

[0037] Furthermore, as shown in Figures 1 to 11, the inner reflective surface 211 of the reflecting light collector 21 is paraboloidal. In this embodiment, the inner reflective surface 211 of the reflecting light collector 21 is paraboloidal; in particular, the longitudinal section of the reflecting light collector 21 runs parabolically from its base to its top. The luminaire 11 (incoherent light source) is arranged at the base of the reflecting light collector 21, with its luminous center located at the focal point of the parabolic surface.

[0038] The optical principle is as follows: Light emanating from the focal point is reflected from the parabolic surface and emitted in a direction parallel to the axis of symmetry. This embodiment utilizes this property to convert the divergent light from the luminaire element 11 into a nearly parallel collimated beam of light. This effectively compresses the divergence angle of the beam, improves its concentration and directionality, reduces light energy loss, and thus increases the projection brightness. This structure is particularly suitable for short-throw projection scenarios with a projection ratio of 0.2 to 1.0 and enables high-brightness imaging at relatively short projection distances.

[0039] As shown in Figures 1 to 11, the light-collecting assembly further comprises at least one Fresnel lens 23. The Fresnel lens 23 is mounted on a light-exit side of the reflecting light collector 21 and is arranged between the display module 30 and the reflecting light collector 21. In this embodiment, the light-collecting assembly is supplemented by a Fresnel lens 23 as a secondary beam-shaping module, which is arranged on the light-exit side of the reflecting light collector 21 and in front of the display module 30. The side of the Fresnel lens 23 facing the light-emitting element is a smooth surface, while the side facing the display module 30 is provided with concentric groove structures from the center to the periphery. This serves to secondarily shape and focus the light beam, so that the central and peripheral light illuminate the effective area of ​​the display module 30 uniformly.By adjusting the groove depth, spacing, or material, the divergence angle of the light beam can be controlled to adapt to different projection distances and field of view areas. For long-distance projection (small field of view), a Fresnel lens 23 with deeper grooves or a specific spacing can be used to narrow the divergence angle of the light beam to within ±10°; for short-distance projection (large field of view), a Fresnel lens 23 with shallower grooves or closer spacing can be used to widen the divergence angle to more than ±30°.

[0040] Furthermore, as shown in Figures 1 to 3, the light-collecting assembly is also provided with a Fresnel lens 23. A thermal insulation lens 63 is also provided between the Fresnel lens 23 and the display module 30. This thermal insulation lens 63 is fixed in the tube via a groove or a positioning ring, and its optical surface is coated with an infrared reflection or absorption layer. After assembly, the light beam, focused by the reflecting light collector 21 and folded over the reflection mirror 50, first passes through the Fresnel lens 23 for secondary collimation and shaping, then through the thermal insulation lens 63, and finally falls onto the display module 30.Functionally, the thermal insulation lens 63 possesses spectral selectivity for the light emitted by the light source: it exhibits high transmission in the visible range to ensure the illumination brightness and color rendering of the pattern, while efficiently reflecting or absorbing the infrared range. Thus, after passing through the thermal insulation lens 63, the heat-carrying infrared radiation is effectively filtered out, significantly reducing the temperature of the light striking the display module 30. This prevents deformation, aging, or fading of the display module 30 (e.g., a film or LCD screen) due to long-term heat exposure.Since the thermal insulation lens 63 is located at the end of the beam path, its plane-parallel plate structure does not significantly impair the collimation and uniformity of the light beam, so that the image quality is maintained while effectively reducing the thermal load.

[0041] Furthermore, as shown in Figures 1 to 11, the distance between the Fresnel lens 23 and the display module 30 is greater than 3 mm and less than 12 mm. In this embodiment, a distance of 3–12 mm between the Fresnel lens 23 and the display module 30, precisely adjusted by a limiting ring or a mounting frame, achieves moderate scattering of the light beam before it reaches the display module 30, avoids bright spots, and ensures the uniformity of the edge illumination. This distance can be finely adjusted according to the thickness of the display module 30 or the projection distance to optimize the uniformity of the light beam and the image sharpness.

[0042] Furthermore, as shown in Figures 1 to 11, the distance between the Fresnel lens 23 and the light source 11 is greater than 8 mm and less than 40 mm. In this embodiment, a distance of 8–40 mm between the Fresnel lens 23 and the light source 11, which is fixed by a holder or a limiting structure, allows the primary focusing by the reflecting light collector 21 and the secondary shaping by the Fresnel lens 23 to occur sequentially. This prevents excessive concentration or dispersion of the light beam, ensures uniform illumination of the display module 30, and simultaneously improves the luminous efficacy and projection quality. This module distance can be adjusted to accommodate different projection distances, spot sizes, and brightness requirements.

[0043] As shown in Figures 8 to 11, the projection device further comprises a reflector 50 arranged between the light-collecting assembly and the display module 30; the predetermined beam path 22 includes a first beam path 221 from the illuminating element 11 to the reflector 50 and a second beam path 222 from the reflector 50 to the display module 30; an angle is formed between the first beam path 221 and the second beam path 222. In this embodiment, the reflector 50 serves as a beam path deflection module; subordinate examples include a plane mirror or a triangular prism mounted between the light-collecting assembly and the display module 30 to deflect light from the first beam path 221 into the second beam path 222 and to illuminate the display module 30.

[0044] The folded beam path design described above allows this embodiment to significantly shorten its longitudinal dimensions while maintaining the coaxiality of the optical axis and image sharpness, optimizing internal space requirements, and providing larger heat dissipation channels for the light-collecting assembly and the display module 30. This improves the problem of insufficient heat dissipation common in compact projection devices. At the same time, this design reduces the influence of light aberrations on the sharpness of the projected image 41 and enables a high-quality projection display.

[0045] Furthermore, the first beam path 221 and the second beam path 222 form a right angle. By mounting the reflector 50 at an angle of 45°, the direction of the light is deflected perpendicularly, thereby reducing the required longitudinal space while maintaining beam concentration and uniformity. This is advantageous for short-throw or ultra-short-throw projection designs as well as for the arrangement of heat dissipation channels.

[0046] Furthermore, as shown in Fig. 3, the reflecting mirror 50 is either a triangular prism or a plane mirror. In this embodiment, the triangular prism achieves highly efficient reflection through total internal reflection, while the plane mirror is simple in design and cost-effective. The function of this module is to flexibly adjust the beam direction while maintaining uniformity of light and image sharpness, whereby the appropriate type of reflection can be selected depending on the size of the projection device.

[0047] As shown in Figures 8 to 11, the light-collecting assembly further comprises at least one Fresnel lens 23. The Fresnel lens 23 is mounted on a light-exit side of the reflector 50 and arranged between the display module 30 and the reflector 50. In this embodiment, the light-collecting assembly is supplemented by a Fresnel lens 23 as a secondary beam-shaping module; subordinate examples include single or multiple lenses mounted on the light-exit side of the reflector 50 and in front of the display module 30 to collimate and focus the light beam and ensure uniform illumination of the display module 30. By adjusting the groove depth, spacing, or material, the divergence angle of the light beam is optimized to adapt to different projection distances and viewing field requirements and to achieve high-brightness, uniform illumination.

[0048] Furthermore, as shown in Figures 8 to 11, the light source assembly 10 is also provided with at least one light-collecting lens element 12. The light-collecting lens element 12 is arranged on a light-exit side of the luminaire 11. In this embodiment, the light-collecting lens element 12 is a convex lens or a Fresnel lens 23. Its optical axis coincides with the central axis of the reflecting light collector 21, and it is located on the emission beam path of the luminaire 11. The optical principle is as follows: Part of the light emitted by the luminaire 11 strikes the light-collecting lens element 12 directly, while another part is reflected by the parabolic surface, becomes parallel light, and then strikes the light-collecting lens element 12.The light-collecting lens element 12 performs a secondary focusing of the incident light, further compressing the divergence angle of the light beam and simultaneously improving the uniformity of the light spot. The combination of the parabolic surface with the light-collecting lens element 12 achieves efficient collection and shaping of the light energy from the light source, resulting in a more concentrated and uniform light beam entering the subsequent display module 30, thus significantly increasing the projection brightness and image quality.

[0049] Furthermore, as shown in Figures 1 to 11, the imaging assembly comprises at least three aspherical lenses with positive refractive power and at least one aspherical lens with negative refractive power, arranged sequentially along a projection direction of the display module 30. In this embodiment, the lens with negative refractive power serves to widen the field of view, while the lenses with positive refractive power serve to focus the light beam and correct aberrations. The combination of several aspherical lenses enables high-resolution imaging in a small volume, ensures clarity in the center and at the edges, and adapts to different sizes of the display module 30 and projection distances.

[0050] In particular, the imaging assembly comprises a first lens element 42, a second lens element 43, a third lens element 44, and a fourth lens element 45, arranged in that order from the projection surface side along the optical axis to the image source side. Their specific properties are as follows: The first lens element 42 is a double-sided aspheric lens with negative refractive power, the projection-surface side of which is concave to widen and shape the entire optical system and ultimately to effectively output a low-distortion, wide-angle projection image; its image-source side is convex to widen the beam path and to cooperate with the beam path system to correct aberrations.

[0051] The second lens element 43 is a double-sided aspherical lens with positive refractive power, the projection-surface side of which is convex in order to cooperate with the system in aberration correction, to effectively focus the beam path and to direct it into the upstream, widening first lens element 42; its image-source side is convex in order to effectively direct the light exiting from the aperture 46 into the widening front part.

[0052] The third lens element 44 is a double-sided aspheric lens with positive refractive power, the projection-surface side of which is concave to shape the effective beam path before being guided to the aperture 46; its image-source side is convex and, by combining materials with different refractive indices compared to the fourth lens element 45, achieves an achromatic function.

[0053] The fourth lens element 45 is a double-sided aspherical lens with positive refractive power, the projection-surface side of which is convex to focus the light entering the system and direct it into the third lens element 44; its image-source side is convex to effectively collect the light passing through the display module 30 and direct it into the optical system.

[0054] Additionally, the refractive power is expressed as the inverse of the focal length.

[0055] As shown in Figures 1 to 11, the imaging assembly further comprises an aperture 46. The aperture 46 is arranged between lens elements of the imaging assembly and is designed to limit the beam aperture. In this embodiment, the imaging assembly is supplemented by an aperture module 46; subordinate examples include a fixed aperture or an adjustable aperture 46 arranged between lens elements to limit the beam aperture, reduce stray light, and improve the contrast and clarity of the projected image 41. The aperture module 46 can also adjust the luminous flux according to different projection brightness and depth-of-field requirements, thus increasing the adaptability of the projection effect.

[0056] Furthermore, as shown in Fig. 14, the display module 30 comprises a circular or elliptical effective display area 31. The effective display area 31 is arranged coaxially with the predetermined beam path 22. A cross-sectional shape of the beam path at a light exit surface of the reflecting light collector 21 is adapted to the shape of the effective display area 31. In this embodiment, by designing the effective display area 31 as circular or elliptical, adapted to the propagation characteristics of the light beam, peripheral blurring and ghost images after the light has passed through the display module 30 can be effectively reduced, thereby ensuring sharp edges of the projected image 41.The coaxial arrangement of the display module 30 with the optical axis ensures that the light beam completely covers the effective display area 31, thus improving light energy utilization. Adapting the module to the shape of the light collector's light-emitting surface enables uniform illumination and clear projection. Depending on specific requirements, the display module 30 can be replaced with different shapes or sizes to accommodate varying resolution, brightness, and color requirements, thereby increasing the system's flexibility and applicability.

[0057] Furthermore, as shown in Figures 5 to 7, several illuminating elements 11 are provided. These elements are arranged at intervals around an inner center point of the reflecting light collector 21. The illuminating elements 11 form an angle with the base of the reflecting light collector 21. In this embodiment, the illuminating elements 11 are arranged uniformly around the inner center point of the reflecting light collector 21 and form an angle with the base. Their function is to increase brightness, improve the uniformity of the light beam, and adjust the light distribution by varying the number and arrangement of the light sources in order to optimize the light intensity for different projection distances.

[0058] As shown in Figures 1 to 11, the projection device further comprises a heat dissipation device 60. The heat dissipation device 60 has an air duct. The display module 30 is arranged in the air duct. A fan is arranged in the air duct. The fan is designed to direct an airflow over a surface of the display module 30 and to dissipate heat from the display module 30. In this embodiment, the heat dissipation module serves to cool the display module 30; specifically, it can be a fan and an air duct. The display module 30 is arranged in the air duct, and the fan drives the airflow over the surface of the display module 30 to dissipate heat, thus ensuring temperature stability at high brightness or during long projection durations, improving reliability, and simultaneously protecting the service life of the light source and the display module 30.

[0059] Furthermore, the lens element fulfills the following conditions: f / EPD<2.0; TTL / BFL<8.4, where f denotes the effective focal length of the lens element, EPD denotes the entrance pupil diameter of the lens element, TTL denotes the total optical length of the lens element, and BFL denotes the rear focal length of the lens element.

[0060] This design optimizes the balance between lens length and aperture, creates a compact imaging assembly while ensuring focusing capability, projection brightness and image sharpness, making it suitable for short-throw or ultra-short-throw projection.

[0061] The present utility model further provides an optical device for a projection lamp. As shown in Figures 20 and 21, the optical device comprises a light source assembly 10, a light-collecting assembly, a display module 30, and an imaging assembly. The specific structures of the light source assembly 10, the light-collecting assembly, and the display module 30 are as described in the preceding embodiments. Since this optical device incorporates all the technical solutions of the preceding embodiments, it exhibits at least all the advantageous effects achieved by the technical solutions of the preceding embodiments, which will not be discussed in detail here.

[0062] The imaging assembly comprises an imaging lens 47, a focusing lens 48, and a wide-angle lens 49, arranged sequentially along a projection direction of the display module 30. The focusing lens 48 comprises a fifth lens element 481 and a sixth lens element 482, the sixth lens element 482 being positioned between the fifth lens element 481 and the imaging lens 47. The fifth lens element 481 has a positive refractive power; one object side of the fifth lens element 481 is convex, and one image side of the fifth lens element 481 is concave. The sixth lens element 482 has a negative refractive power; one object side of the sixth lens element 482 is convex, and one image side of the sixth lens element 482 is concave.

[0063] In this embodiment, the imaging assembly is mounted in the following order along the optical axis on the projection side of the display module 30: The imaging lens 47 (which may be a single lens or a combination of several lenses to collect the pattern light beam passing through the display module 30 and to produce a primary real image) is located closest to the display module 30; next along the optical axis is the focusing lens group (consisting of the fifth lens element 481 and the sixth lens element 482 in this order, with the sixth lens element 482 being arranged between the fifth lens element 481 and the imaging lens 47); the wide-angle lens 49 is located furthest away.Regarding the assembly, all lenses are arranged coaxially in a tube; the distance between the lenses can be positioned by axial positioning elements (such as stop rings, spring washers or spacers) to ensure the consistency of the optical axis.

[0064] Functionally, the fifth lens element 481 is a positively refractive lens with a convex object side and a concave image side; the sixth lens element 482 is a negatively refractive lens with a convex object side and a concave image side. The focusing lens 48, formed from the fifth lens element 481 and the sixth lens element 482, acts as a whole to perform complex light deflection and wavefront transformation of the light beam coming from the imaging lens 47. The combination of positive and negative refractive forces, in conjunction with the specific surface shapes (both are convex-concave meniscus shapes), effectively compensates for the spherical aberration and field curvature generated by the system and adjusts the principal beam angle of the exiting light beam so that it is compatible with the subsequent wide-angle lens 49, thus laying the foundation for the subsequent projection with a large field of view and suppressing edge distortion.Overall, the combination of positive and negative refractive forces within a compact structure achieves pre-shaping of the beam path and preliminary aberration compensation, thereby improving the sharpness and uniformity of the projected image and facilitating wide-angle projection. This arrangement allows the pattern on the display module 30 to reduce edge blur and distortion after three-stage processing—imaging, adjustment, and wide-angle magnification—while maintaining a large field of view; the structure is compact and facilitates the realization of high-resolution projection in small volume projectors.

[0065] It should be explained that the object side of a lens is the side facing the display module 30, and the image side of a lens is the side facing away from the display module 30. The refractive power of a lens is the reciprocal of its focal length and serves to express the lens's ability to refract light, denoted by the symbol Φ. Its numerical calculation follows the formula Φ = 1 / f, where f is the focal length of the lens. The refractive power of a convex lens is positive (i.e., positive refractive power), while the refractive power of a concave lens is negative (i.e., negative refractive power).

[0066] Furthermore, as shown in Figures 20 and 21, the curvature of the object side of the fifth lens element 481 is equal to the curvature of the image side of the sixth lens element 482, and the object side of the fifth lens element 481 is cemented to the image side of the sixth lens element 482. In this embodiment, the object side of the fifth lens element 481 (referred to as surface A) and the image side of the sixth lens element 482 (referred to as surface B) are designed with the same curvature and cemented together at the optical contact surfaces using optical adhesive (or a low-refractive-index optical adhesive) to form a single component. The cementing eliminates the original air interface between surfaces A and B and thus corrects the chromatic aberration during pattern propagation.By selecting glass materials with different Abbe numbers (dispersion coefficients) for the fifth lens element 481 (positive refractive power) and the sixth lens element 482 (negative refractive power), the refraction at the cemented surface can compensate for the axial chromatic aberration introduced by the imaging lens 47, thereby improving the color purity and overall sharpness of the projected image. Simultaneously, the cementing also reduces reflection loss at the interfaces, thus effectively increasing the contrast and sharpness of the projected image.

[0067] The foregoing embodiments represent only preferred embodiments of the present utility model and are not intended to limit the scope of protection of the present utility model. Any equivalent structural modification made in accordance with the inventive concept of the present utility model using the description and drawings of the present utility model, as well as any direct or indirect application in other related technical fields, falls within the scope of protection of the present utility model.

[0068] The present utility model discloses a projection device and an optical device for a projection lamp. The projection device comprises a light source assembly, a light-collecting assembly, a display module, and an imaging assembly. The light source assembly comprises at least one luminaire; the light-collecting assembly comprises a reflective light collector with an internal reflective surface, wherein the luminaire element is arranged inside the collector and the internal reflective surface reflects light and focuses it onto a predetermined beam path; the display module is arranged in the predetermined beam path and serves to carry and display an image; the imaging assembly is arranged on the light-exit side of the display module and comprises at least one lens element for projecting the image onto a projection surface.The projection ratio of the projection device is limited to a value greater than or equal to 0.2 and less than or equal to 1.0, where the projection ratio is the ratio of a projection distance to the horizontal width of a projected image and can be configured by adjusting the focal length of the imaging assembly or the size of the display module. The present utility model achieves high light output, high uniformity, miniaturization, and optimized short-throw projection capability.

Claims

[1] Projection device, characterized by that it includes: a light source assembly, wherein the light source assembly comprises at least one luminaire element designed to emit incoherent light; a light collecting assembly, wherein the light collecting assembly comprises a reflective light collector, wherein the reflective light collector has an inner reflective surface, wherein the inner reflective surface is configured to reflect the light emitted by the luminaire and to focus it onto a predetermined beam path, wherein the at least one luminaire is arranged inside the reflective light collector; a display module, wherein the display module is configured to carry and display a static or dynamic image, wherein the display module is arranged in the predetermined beam path of the light-collecting assembly such that the light treated by the light-collecting assembly falls onto the display module; an imaging assembly, wherein the imaging assembly is arranged on a side of the display module facing away from the light-collecting assembly and is configured to project the image displayed on the display module onto a projection surface to form a projection image, wherein the imaging assembly comprises at least one lens element; wherein the projection ratio of the projection device is limited to a value greater than or equal to 0.2 and less than or equal to 1.0, wherein the projection ratio is a ratio of a projection distance to a horizontal width of the projection image, wherein the projection distance is a straight-line distance from a light-exit side of the projection device to the projection surface, and wherein the projection ratio can be configured by adjusting the focal length of the imaging assembly or the size of the display module. [2] Projection device according to claim 1, characterized by that the inner reflective surface of the reflecting light collector is paraboloid in shape. [3] Projection device according to claim 1, characterized by, that the light-collecting assembly further comprises at least one Fresnel lens, wherein the Fresnel lens is mounted on a light-exit side of the reflecting light collector, and wherein the Fresnel lens is arranged between the display module and the reflecting light collector. [4] Projection device according to claim 3, characterized by that the distance between the Fresnel lens and the display module is greater than 3 mm and less than 12 mm. [5] Projection device according to claim 3, characterized by , that one side of the Fresnel lens facing the light element is a smooth surface, and one side of the Fresnel lens facing the display module is provided with several concentric groove structures at intervals from the center to a circumferential side. [6] Projection device according to claim 3, characterized by that the distance between the Fresnel lens and the light element is greater than 8 mm and less than 40 mm. [7] Projection device according to claim 1, characterized by , that the projection device further comprises a reflection mirror, wherein the reflection mirror is arranged between the light-collecting assembly and the display module; wherein the predetermined beam path comprises a first beam path from the luminaire element to the reflection mirror and a second beam path from the reflection mirror to the display module, wherein an angle is formed between the first beam path and the second beam path. [8] Projection device according to claim 7, characterized by that the angle between the first beam path and the second beam path is a right angle. [9] Projection device according to claim 7, characterized by that the reflection mirror is a triangular prism or a plane mirror. [10] Projection device according to claim 7, characterized by, that the light-collecting assembly further comprises at least one Fresnel lens, wherein the Fresnel lens is mounted on a light-exit side of the reflecting mirror, and wherein the Fresnel lens is arranged between the display module and the reflecting mirror. [11] Projection device according to claim 7, characterized by , that the light source assembly is further provided with at least one light collecting lens element, wherein the light collecting lens element is arranged on a light exit side of the luminaire element. [12] Projection device according to claim 1, characterized by that the imaging assembly comprises at least three aspherical lenses with positive refractive power and at least one aspherical lens with negative refractive power, arranged sequentially along a projection direction of the display module. [13] Projection device according to claim 12, characterized by, that the imaging assembly further comprises an aperture, wherein the aperture is arranged between the lens elements of the imaging assembly to limit a beam aperture. [14] Projection device according to claim 1, characterized by that the display module comprises a circular or elliptical effective display area, wherein the effective display area is arranged coaxially with the predetermined beam path; wherein a cross-sectional shape of the beam path at a light exit surface of the reflecting light collector is adapted to the shape of the effective display area. [15] Projection device according to claim 1, characterized by that several luminaire elements are provided, wherein the several luminaire elements are arranged at intervals around an inner center point of the reflecting light collector, the luminaire elements forming an angle with a base of the reflecting light collector. [16] Projection device according to claim 1, characterized by , that the projection device further comprises a heat dissipation device, wherein the heat dissipation device has an air duct, wherein the display module is arranged in the air duct, wherein a fan is arranged in the air duct, wherein the fan is configured to direct an airflow from a surface of the display module and to dissipate heat from the display module. [17] Projection device according to claim 1, characterized by that the lens element satisfies the following condition equations: f / EPD<2.0; TTL / BFL<8.4, where f denotes an effective focal length of the lens element, EPD denotes an entrance pupil diameter of the lens element, TTL denotes a total optical length of the lens element, and BFL denotes a rear focal length of the lens element. [18] Projection device according to claim 1, characterized by , that the display module is designed to carry and display a static or dynamic image of a Milky Way starry sky, or an image of celestial bodies, or an image of a natural landscape. [19] Optical device for a projection lamp, characterized by that it includes: a light source assembly, wherein the light source assembly comprises at least one luminaire element designed to emit incoherent light; a light collecting assembly, wherein the light collecting assembly comprises a reflective light collector, wherein the reflective light collector has an inner reflective surface, wherein the inner reflective surface is configured to reflect the light emitted by the luminaire and to focus it onto a predetermined beam path, wherein the at least one luminaire is arranged inside the reflective light collector; a display module, wherein the display module is configured to carry and display a static or dynamic image, wherein the display module is arranged in the predetermined beam path of the light-collecting assembly such that the light treated by the light-collecting assembly falls onto the display module; an imaging assembly, wherein the imaging assembly is arranged on a side of the display module facing away from the light-collecting assembly and is configured to project the image displayed on the display module onto a projection surface to form a projection image, wherein the imaging assembly comprises an imaging lens, focusing lens and wide-angle lens arranged successively along a projection direction of the display module, wherein the focusing lens comprises a fifth lens element and a sixth lens element, and wherein the sixth lens element is arranged between the fifth lens element and the imaging lens; wherein the fifth lens element has a positive refractive power, an object side of the fifth lens element is convex and an image side of the fifth lens element is concave; wherein the sixth lens element has a negative refractive power, an object side of the sixth lens element is convex and an image side of the sixth lens element is concave; wherein a projection ratio of the optical device is limited to a value greater than or equal to 0.2 and less than or equal to 1.0, wherein the projection ratio is a ratio of a projection distance to a horizontal width of the projection image, wherein the projection distance is a straight-line distance from a light exit side of the projection device to the projection surface, and wherein the projection ratio can be configured by adjusting the focal length of the imaging assembly or the size of the display module. [20] Optical device for a projection lamp according to claim 19, characterized by , that a curvature of the object side of the fifth lens element is equal to a curvature of the image side of the sixth lens element and that the object side of the fifth lens element is cemented to the image side of the sixth lens element.

Images