Projection light machine and electronic device

Abstract

The application relates to a projection light machine and electronic equipment, the projection light machine comprising a laser light source, a light source lens group, an eye lens, a relay lens group, a prism group and a DMD module, the light source lens group comprising a converging optical unit, a light homogenizing rod and a collimating optical unit, the incident surface of the light homogenizing rod being located on the back focal plane of the converging optical unit; a distance is left between the collimating optical unit and the light homogenizing rod and the eye lens on the light path; the relay lens group comprises a relay lens, the relay lens is arranged immediately adjacent to the eye lens on the light path, an air gap is formed between the relay lens and the eye lens, and the projection of the relay lens covers the projection of the eye lens; wherein the back focal plane of the light source lens group is not on the eye lens and not on the relay lens, so that the light beam emitted by the laser light source is irradiated to the eye lens in the form of a light spot after being processed by the light source lens group. The application can reduce the thermal damage on the optical elements such as the eye lens, thereby ensuring the stability of the optical elements and improving the picture effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of projection technology, in particular to a projection light machine and electronic equipment. BACKGROUND

[0002] With the increasingly mature semiconductor technology, the laser light source manufactured by semiconductor laser tube (i.e. LD) has the advantages of high electro-optical conversion efficiency, long service life, high color saturation, small etendue and high brightness, which are increasingly prominent, especially in the projection field. However, in the optical path of the projection device, there are often many optical elements, and when the laser light source is selected as the illumination device, the optical elements are easily damaged at the convergence point due to the high energy density of the laser light source, and the speckle phenomenon is also likely to occur, and the light uniformity is relatively difficult.

[0003] In order to solve the above problems, in some projection devices, a laser light source with low power is used, but this method will obviously affect the picture effect of projection. SUMMARY

[0004] Based on the above status, the main purpose of the present application is to provide a projection light machine and electronic equipment, by setting the uniform light rod, the collimating optical unit and the compound eye lens and other optical elements, the high-power laser light source can be used to ensure the brightness of the projection picture while reducing the heat concentration of the laser energy on the compound eye lens and other optical elements, so as to ensure the stability of each optical element and improve the picture effect.

[0005] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0006] The first aspect of the present application provides a projection light machine, comprising a laser light source, a light source lens group, a relay lens group, a prism group and a DMD module which are arranged in sequence along an optical path, and further comprising a compound eye lens arranged between the light source lens group and the relay lens group along the optical path,

[0007] The light source lens group comprises a converging optical unit, a uniform light rod and a collimating optical unit which are arranged in sequence along the optical path, and the projection of the converging optical unit covers the projection of the laser light source in the projection along the optical path; the incident surface of the uniform light rod is located on the back focal plane of the converging optical unit; and a distance is left between the collimating optical unit and the uniform light rod and the compound eye lens along the optical path;

[0008] The relay lens group comprises a relay lens, and the relay lens is arranged in close proximity to the compound eye lens along the optical path, an air gap is formed between the two, and the projection of the relay lens covers the projection of the compound eye lens along the optical path;

[0009] The back focal plane of the light source lens group is not on the fly-eye lens and not on the relay lens, so that the light beam emitted by the laser light source is irradiated to the fly-eye lens in the form of a spot after being processed by the light source lens group, the light beam processed by the fly-eye lens enters the relay lens group and the prism group in turn and is irradiated to the DMD module, and the light beam reflected by the DMD module is irradiated to the projector again through the prism group.

[0010] Preferably, on the light path, the back focal plane of the light source lens group is located on the upstream side of the entrance surface of the fly-eye lens.

[0011] Preferably, on the light path, the exit surface of the light homogenizing rod is arranged on the front focal plane of the collimating optical unit.

[0012] Preferably, on the light path, the distance between the exit surface of the light homogenizing rod and the collimating optical unit is greater than the focal length of the collimating optical unit.

[0013] Preferably, the back focal plane of the light source lens group is located between the fly-eye lens and the relay lens.

[0014] Preferably, the distance between the exit surface of the light homogenizing rod and the collimating optical unit is less than the focal length of the collimating optical unit.

[0015] Preferably, the collimation angle of the light rays output by the collimating optical unit is not greater than the maximum incidence angle of the light rays of the fly-eye lens.

[0016] Preferably, in the projection along the light path, the projection of the relay lens covers the projection of the fly-eye lens, and the distance between the first relay lens and the fly-eye lens is not less than 0.1 mm.

[0017] Preferably, the distance between the entrance surface of the fly-eye lens and the back focal plane of the light source lens group is 0.8-1.5 mm, and the number of reflections of the exit light beam of the converging optical unit on the light homogenizing rod is greater than or equal to 3.

[0018] Preferably, the light source lens group further comprises a diffusion sheet, and the diffusion sheet is arranged at at least one of the following positions:

[0019] (1) between the light homogenizing rod and the converging optical unit, and close to or attached to the entrance surface of the light homogenizing rod;

[0020] (2) between the light homogenizing rod and the collimating optical unit, and close to or attached to the exit surface of the light homogenizing rod;

[0021] (3) between the collimating optical unit and the fly-eye lens, and close to the entrance surface of the fly-eye lens.

[0022] Preferably, a mirror is further included, and a plurality of optical elements on the light path from the light homogenizing rod to the relay lens group, wherein the mirror is arranged between two adjacent optical elements to reduce the size of the projection light machine in the direction of the optical axis of the light homogenizing rod.

[0023] The second aspect of the present application provides an electronic device, comprising a projection lens and the projection light machine according to any one of the above, and the projection lens is mounted on the light exit side of the projection light machine.

[0024] Preferably, the electronic device is a projection device or a measuring device.

[0025] The projection light machine of the present application, in the light source lens group, a converging optical unit, a light homogenizing rod and a collimating optical unit are arranged in sequence, and an ommatidium lens is arranged, by arranging the entrance surface of the light homogenizing rod on the back focal plane of the converging optical unit, the light emitted by the laser light source can be processed by the converging optical unit and then enter the light homogenizing rod, and the back focal plane of the light source lens group is located outside each relay lens in the relay lens group and the ommatidium lens, thus, all the light processed by the light homogenizing rod is processed by the collimating optical unit and forms a plurality of light spots with a preset area on the entrance surface of the ommatidium lens, instead of a converging point, that is, the light beam entering the light homogenizing rod from a point on the entrance surface of the light homogenizing rod is a light spot on the entrance surface of the ommatidium lens, instead of a point, which can be understood as that the plane where the converging point of the laser and the discrete points of the reflected image of the light homogenizing rod are located is regarded as an object plane, and the plane where the discrete image points formed by the discrete points through the collimating unit is regarded as an image plane, that is, the two planes (the object plane and the image plane) are conjugate to each other, and the energy density of these discrete image points is extremely high, for the optical subsystem formed by the light source lens group, the conjugate plane (the image plane) of the entrance surface (the object plane) of the light homogenizing rod is not on the entrance surface of the ommatidium lens, thus, the discrete conjugate points of the high-energy-density image plane are diffused into light spots with larger area and lower energy density on the entrance surface and inside the ommatidium lens, and the light beam of the laser light source is processed by the light homogenizing rod and the ommatidium lens in sequence, thereby avoiding the formation of high-energy converging points on the ommatidium lens, reducing the thermal damage to the ommatidium lens, reducing the requirements for the optical performance such as light resistance and heat resistance of the ommatidium lens, and avoiding the influence of the whitening / yellowing phenomenon of the ommatidium lens caused by long-time light irradiation on the light transmittance, thereby ensuring the projection effect of the projection light machine in long-term use; and the twice light homogenizing processing by the light homogenizing rod and the ommatidium lens greatly improves the light beam homogenizing effect of the entire projection light machine. Therefore, the present application can use a high-power laser light source to ensure the brightness of the projection picture, while still reducing the thermal damage to the ommatidium lens, prolonging the aging resistance time and ensuring the optical performance.

[0026] Other beneficial effects of the present application will be illustrated in the detailed description of the embodiments by introducing specific technical features and technical solutions, which should be understood by those skilled in the art to bring about the beneficial technical effects. BRIEF DESCRIPTION OF DRAWINGS

[0027] The preferred embodiments of the present application will be described below with reference to the accompanying drawings.

[0028] Figure 1 A schematic diagram of an optical system of a preferred embodiment of the electronic device of the present application;

[0029] Figure 2 A schematic diagram of an optical system of another preferred embodiment of the electronic device of the present application;

[0030] Figure 3 A schematic diagram of a partial optical system of a preferred embodiment of the projection optical machine of the present application;

[0031] Figure 4 A schematic diagram of a partial optical system of another preferred embodiment of the projection optical machine of the present application;

[0032] Figure 5 A schematic diagram of a partial optical system of another preferred embodiment of the projection optical machine of the present application;

[0033] Figure 6 A schematic diagram of a partial optical system of a comparative embodiment of the projection optical machine of the present application.

[0034] In the drawings:

[0035] 100, projection optical machine; 10, laser light source; 20, light source lens group; 21, converging optical unit; 22, light homogenizing rod; 23, collimating optical unit; 24, diffusion sheet; 30, fly-eye lens; 40, relay lens group; 41, relay lens; 50, prism group; 60, DMD module;

[0036] 200, projection lens. DETAILED DESCRIPTION

[0037] The present application will be described below based on the embodiments, but the present application is not limited to only these embodiments. In the following detailed description of the present application, some specific details are described in detail, and the well-known methods, processes, procedures, elements are not described in detail in order to avoid confusion of the essence of the present application.

[0038] In addition, those of ordinary skill in the art should understand that the drawings provided herein are for illustrative purposes only, and the drawings are not necessarily drawn to scale.

[0039] Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to".

[0040] In the description of the present application, it should be understood that the terms "first", "second" and the like are used for descriptive purposes only and are not intended to indicate or imply relative importance. In addition, in the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specified.

[0041] In the prior art, in the projection light machine using laser as light source, some use uniform light rod or compound eye lens for uniform light processing, and some use two uniform light rods. However, the uniform light effect of such optical system is limited by the characteristics of the optical elements themselves, and no matter which way, the uniform light rod or compound eye lens is arranged on the front optical element or the focal plane of the optical system, which is limited by the heat resistance and light resistance of the uniform light rod, especially the compound eye lens. Only low-power laser light source can be used, so the projection picture brightness of the projection light machine is limited.

[0042] In order to solve the above problems, the present application provides a projection light machine 100, referring to Figures 1-5 The projection light machine 100 includes a laser light source 10, a light source lens group 20, a relay lens group 40, a prism group 50 and a DMD module 60 arranged in sequence along the light path, and further includes a compound eye lens 30 arranged between the light source lens group 20 and the relay lens group 40 along the light path. The light source lens group 20 includes a converging optical unit 21, a uniform light rod 22 and a collimating optical unit 23 arranged in sequence along the light path. The projection of the converging optical unit 21 covers the projection of the laser light source 10 in the projection along the light path, that is, the edge of the laser light source 10 does not exceed the converging optical unit 21 when viewed along the direction of the light path, so that the light beam emitted by the laser light source 10 can enter the converging optical unit 21 as much as possible. The entrance surface of the uniform light rod 22 is located on the back focal plane of the converging optical unit 21. There is a distance between the collimating optical unit 23 and the uniform light rod 22 and the compound eye lens 30 on the light path, that is, the collimating optical unit 23 and the uniform light rod 22 are arranged with a distance, and the collimating optical unit 23 and the compound eye lens 30 are also arranged with a distance.

[0043] The relay lens group 40 comprises a relay lens 41, which is arranged next to the compound eye lens 30 in the above-mentioned light path, an air gap is formed between the two, and the projection of the relay lens 41 along the light path covers the projection of the compound eye lens 30. That is, in the entire light path, no other optical lens is arranged between the compound eye lens 30 and the relay lens 41, the distance between the two is very small, basically next to each other; and looking along the light path, the outer edge of the compound eye lens 30 does not exceed the relay lens 41, when the two are both circular optical elements, the diameter of the relay lens 41 needs to be greater than or equal to the compound eye lens 30. By adopting this structure, the outgoing light beam of the compound eye lens 30 can be made to enter the relay lens 41 as much as possible, and the size of the relay lens 41 is minimized, in this way, the stray light generated at this place is reduced as much as possible, avoiding the influence on the final projection picture, at the same time, the size requirement of the projection light machine is relatively low, which can be applied to small projection light machines.

[0044] The back focal plane of the light source lens group 20 is not on the compound eye lens 30 and not on the relay lens 41, so that the light beam emitted by the laser light source 10 is irradiated to the compound eye lens 30 in the form of a spot after being processed by the light source lens group 20, the light beam processed by the compound eye lens 30 enters the relay lens group 40 and the prism group 50 in turn and is irradiated to the DMD module 60, and is reflected by the DMD module 60 and then emitted from the prism group 50 again to the projection light machine 100. That is, the back focal plane of the optical subsystem formed by the light source lens group 20 is arranged in a staggered manner with the compound eye lens 30 and the relay lens 41 downstream thereof, the back focal plane is arranged in a different plane from the incident surface or the exit surface of the compound eye lens 30 and does not pass through the inside of the compound eye lens 30, and of course, the back focal plane is arranged in a different plane from the incident surface and the exit surface of the relay lens 41 and does not pass through the inside of the relay lens 41.

[0045] The above-mentioned projection light machine, the converging optical unit 21, the light homogenizing rod 22 and the collimating optical unit 23 are arranged in the light source lens group 20 in turn, and the compound eye lens 30 is arranged, in the light path of the entire projection light machine, the light beam emitted by the laser light source 10 is first converged by the converging optical unit 21 to the incident surface of the light homogenizing rod 22, the first light homogenizing process is performed in the light homogenizing rod 22, then the light beam out of the light homogenizing rod 22 is collimated by the collimating optical system 23 and then the second light homogenizing process is performed by the compound eye lens 30, and then the light beam is irradiated to the DMD module 60 by the relay lens group 40 and the prism group 50.

[0046] Since the energy of the light beam directly emitted from the laser light source 100 is high, especially for a high-power laser light source, and the energy density of the light beam is higher after the converging action of the converging optical unit 21, if the light beam is directly processed by the fly-eye lens, the laser light source is focused into a thin light beam after the rough light beam is focused into a thin light beam, and since only a small area of the fly-eye lens is irradiated, the performance requirement of the fly-eye lens is too high, and long-term high-power light beam irradiation of the fly-eye lens not only makes it easy to turn white or yellow, reduces its light transmittance to the light beam, but also causes temperature rise due to light irradiation. Even if the converging optical unit 21 is removed, the light beam emitted by the laser light source 10 is directly irradiated to the fly-eye lens, and due to the high energy of the laser light beam, the above problems still exist. The structure of the fly-eye lens and the fly-eye lens in the present application uniformly light the laser light beam of the entire optical system twice, which avoids the above problems.

[0047] In some embodiments, although the fly-eye lens 30 and the fly-eye lens 30 are used at the same time, the entrance surface of the fly-eye lens 22 is usually arranged on the back focal plane of the converging optical unit 21, the exit surface is arranged on the front focal plane of the collimating optical unit 23, and the entrance surface of the fly-eye lens 30 is arranged on the back focal plane of the entire light source lens group 20, as shown in Figure 6 In this optical subsystem of the light source lens group 20, the conjugate surface of the entrance surface of the fly-eye lens 22 (i.e. the back focal plane of the light source lens group 20) is located on the entrance surface of the fly-eye lens 30, and the conjugate surface of the exit surface is located on the exit surface of the fly-eye lens 30, i.e. the surface A and the surface A' are conjugate surfaces, and the surface B and the surface B' are conjugate surfaces (the surface A and the surface A', the surface B and the surface B' in other figures are also the same), in this optical system, the spot size on the entrance surface of the fly-eye lens 30 is the smallest, the etendue is small, and therefore the light efficiency is the best, but the energy of the points on these conjugate surfaces is the most concentrated, which requires high light resistance and heat resistance of the fly-eye lens 30. Of course, as described in the background art, a lower-power laser light source can be used, but the brightness of the projected image will be lost.

[0048] In this application, the back focal plane of the subsystem formed by the light source lens group 20 is positioned outside the compound eye lens 30. This means that even if the compound eye lens 30 is positioned downstream in the light homogenization process, it will not be at the point of highest energy concentration of the entire beam. Instead, it will illuminate the compound eye lens 30 (including its incident surface, exit surface, and interior) as light spots. Thus, all the light rays processed by the homogenizing rod 22, after being processed by the collimating optical unit 23, will form light spots of a predetermined area on the incident surface of the compound eye lens 30, rather than convergence points. A light spot at a certain point on the incident surface of the homogenizing rod 22 becomes a light spot rather than a point when it reaches the incident surface of the compound eye lens 30. This can be understood as considering the plane containing the laser convergence point and the discrete points of its reflected images (including primary and secondary reflections) after passing through the homogenizing rod as the object plane, and the plane containing the discrete image points formed by the collimating unit as the image plane. That is, these two planes (object plane and image plane) are conjugate to each other. The energy density of these discrete image points is extremely high. For the optical subsystem formed by the light source lens group 20, this is the plane of incidence of the homogenizing rod 22. ( The conjugate plane (i.e., the image plane) of the object plane is not on the incident plane of the compound eye lens 30. This causes the high-energy-density discrete conjugate points of the image plane to diffuse into larger, lower-energy-density light spots on the incident plane and within the compound eye lens. Therefore, it avoids the formation of high-energy convergence points on the compound eye lens 30, reducing the light energy density on the compound eye lens 30. This reduces the requirements for the compound eye lens's heat resistance, light resistance, and other optical properties, and avoids the whitening / yellowing phenomenon that may occur when the compound eye lens is exposed to light for a long time, thus affecting its transmittance and ensuring the projection effect of the projection engine during long-term use. Furthermore, the two-stage homogenization process using the homogenizing rod 23 and the compound eye lens 30 significantly improves the homogenization effect of the entire projection engine, enhancing the quality of the projected image. Moreover, this application can use a high-power laser light source to ensure the brightness of the projected image while still reducing damage to the compound eye lens, extending its aging resistance time, and ensuring its optical performance.

[0049] It should be noted that the above description refers to the illumination of the compound eye lens in the form of a light spot. This light spot is relative to a single point of light; it is a relative description and does not refer to the entire relatively thick beam emitted from the laser source 10. Rather, it refers to a focal point formed on the incident surface of the homogenizing rod 22, such as... Figures 1-5 Point C1, after passing through the homogenizing rod 22 and the collimating optical system 23, is no longer a single point of light of the same size when it reaches the compound eye lens 30. Instead, it forms a light spot with an area larger than point C1 (i.e., the base of a light cone with C1' as its apex). Throughout the entire optical path, the area of ​​the light spot on the compound eye lens 30 is necessarily larger than the area of ​​the discrete points on the image plane. In the figure, points A1 and A1', A2 and A2', and C1 and C1' are each a pair of conjugate points.

[0050] The converging optical unit 21 can include one optical lens or two or more optical lenses. In any case, the optical lenses forming the converging optical unit 21 collectively form an optical subsystem that converges the light beam, and the front focal plane and the back focal plane refer to the front focal plane and the back focal plane of the entire optical subsystem formed by the optical lenses of the converging optical unit 21. Similarly, the collimating optical unit 23 can include one optical lens or multiple optical lenses, and the front focal plane and the back focal plane refer to the front focal plane and the back focal plane of the entire optical subsystem formed by the optical lenses of the collimating optical unit 23. Similarly, the relay lens group 40 can include one relay lens 41 (as shown in Figure 2 ) or multiple relay lenses 41 (as shown in Figure 1 ), and the front focal plane and the back focal plane refer to the front focal plane and the back focal plane of the entire optical subsystem formed by the optical lenses of the relay lens group 40. When the relay lens group 40 includes multiple relay lenses, the relay lens located at the most upstream position in the optical path (i.e., the relay lens closest to the fly-eye lens 30) forms an air gap with the fly-eye lens 30.

[0051] The back focal plane of the light source lens group 20 can be located on the upstream side of the entrance surface of the fly-eye lens 30 or on the downstream side of the entrance surface of the fly-eye lens.

[0052] In a preferred embodiment, as shown in Figure 1 , Figure 3 and Figure 4 , the back focal plane of the light source lens group 20 is located on the upstream side of the entrance surface of the fly-eye lens 30 in the optical path. This arrangement allows the back focal plane to avoid the optical elements located on the downstream side of the fly-eye lens 30, especially the relay lens 41 adjacent to the fly-eye lens 30. Therefore, in the entire optical path design, the adjustment is mainly performed on the optical path portion of the light source lens group 20 and the fly-eye lens 30, and the optical path portion located on the downstream side of the fly-eye lens 30 can be adaptively moved along with the fly-eye lens 30, thereby greatly reducing the complexity of the optical path design of the projection optical engine.

[0053] Specifically, in one approach, the exit surface of the homogenizing rod 22 can be located on the front focal plane of the collimating optical unit 23 in the optical path, i.e., the entire light source lens group 20 is not adjusted, and the relative positions and optical parameters of the optical elements in the entire light source lens group 20 are not changed, and only the fly-eye lens 30 is moved a certain distance away from the collimating optical unit 23 in the optical path, as shown in Figure 6 , Figure 1 , Figure 3As shown, this approach ensures lower requirements for the brightness of the projected image and the heat resistance and light resistance of the compound eye lens 30, while also improving the collimation effect of the beam processed by the collimating optical unit 23, thereby enhancing the overall quality of the projected image. Of course, as the compound eye lens 30 moves away from the collimating optical unit 23, other optical lenses downstream of it in the optical path may make adaptive adjustments.

[0054] In another approach, the distance between the exit surface of the homogenizing rod 22 and the collimating optical unit 23 in the optical path is greater than the focal length of the collimating optical unit 23. That is, the exit surface of the homogenizing rod 23 does not coincide with the front focal plane of the collimating optical unit 23, but is located upstream of the front focal plane of the collimating optical unit 23. Using this method, only the parameters of the light source lens group 20 itself need to be adjusted; the compound eye lens 30 and other optical elements located downstream of it do not require adjustment. Therefore, it does not affect the overall dimensions of the projection engine, and it reduces the number of optical elements that need adjustment during the optical path design process, further reducing the complexity of the optical path design. This allows for the rapid acquisition of the target optical system (because ideally, when designing the entire optical system, it should be based on...). Figure 6 The relative positions of the intermediate light source lens group 20 and the compound eye lens 30 are determined, followed by adjustments to certain units or optical elements; this method is particularly suitable for applications previously used such as... Figure 6 When the projection optical engine of the optical system adopts a split optical engine housing that is divided from the compound eye lens 30, the portion of the optical engine housing downstream of the compound eye lens 30 does not need to be redesigned. Specifically, this can be achieved by setting a collimating optical unit 23 with a preset focal length or by adjusting the position of the collimating optical unit 23 relative to the homogenizing rod 22. Figure 6 In the optical system shown, the focal length of the collimating optical unit 23 can be reduced (e.g., when there is only one optical lens, a smaller focal length optical lens can be replaced; when there are multiple optical lenses, one or more optical lenses can be replaced, or the relative positions between these optical lenses can be adjusted, or a combination of the above two methods can be used simultaneously), without adjusting the relative positions of the optical elements and compound eye lenses within the entire light source lens group 20. Alternatively, only the position of the collimating optical unit 23 as a whole can be moved so that its front focal plane is out of plane with the exit surface of the homogenizing rod 22, relative to... Figure 6 In the optical system shown, with the structure and optical parameters of the collimating optical unit 23 remaining unchanged, the collimating optical unit 23 as a whole is moved a certain distance closer to the compound eye lens 30, such as... Figure 4 As shown (where the dashed lines in the figure represent components in...) Figure 6 (Location at time).

[0055] In another preferred embodiment of the present invention, such as Figure 2As shown, the back focal plane of the light source lens group 20 is located between the fly-eye lens 30 and the relay lens 41, and in the embodiment with multiple relay lenses 41, the back focal plane is located between the fly-eye lens 30 and the relay lens 41 next to it. In a preferred manner, the distance between the exit surface of the homogenizing rod 22 and the collimating optical unit 23 is less than the focal length of the collimating optical unit 23, i.e. the exit surface of the homogenizing rod 22 is not coplanar with the front focal plane of the collimating optical unit 23 and is located on the downstream side of the front focal plane of the collimating optical unit 23. By using a collimating optical unit 23 with a preset focal length or adjusting the position of the collimating optical unit 23 relative to the homogenizing rod 22, the collimating angle of the light rays output by the collimating optical unit 23 is less than the maximum incident angle of the light rays of the fly-eye lens 30, so that the stray light generated by the light beams output from the fly-eye lens 30 is reduced, and the quality and brightness of the projection image are improved. Figure 6 In the embodiment shown, the parameters and positions of other optical elements are not adjusted, and only the focal length of the collimating optical unit 23 is increased, the position of the collimating optical unit 23 is not changed, or the collimating optical unit 23 is moved a certain distance towards the homogenizing rod 22 without adjusting the focal length. In this way, only the parameters of the light source lens group 20 itself need to be adjusted, and the fly-eye lens 30 and other optical elements on the downstream side of the fly-eye lens 30 do not need to be adjusted, so that the overall size of the projection optical engine is not affected, and the number of optical elements to be adjusted during the optical path design process is reduced, further reducing the complexity of the optical path design, so that the target optical system can be quickly obtained (because during the design of the entire optical system, it is ideal to first adjust the relative positions of the light source lens group 20 and the fly-eye lens 30, and then adjust some units or some optical elements); and this method is particularly suitable for projection optical engines using the optical system as shown in Figure 6 Figure 6 When the split optical engine shell is arranged to be split from the fly-eye lens 30, the part of the optical engine shell on the downstream side of the fly-eye lens 30 does not need to be redesigned. Of course, the fly-eye lens 30 can also be moved a preset distance towards the collimating optical unit 23 to achieve the back focal plane of the light source lens group 20 located between the fly-eye lens 30 and the relay lens 41.

[0056] In order to further reduce the stray light generated by the light beams output from the fly-eye lens 30, in a preferred embodiment of the present application, the collimating angle of the light rays output by the collimating optical unit 23 is not greater than the maximum incident angle of the light rays of the fly-eye lens 30, so that the stray light is better reduced, and the quality and brightness of the projection image are improved.

[0057] ​In a preferred embodiment, the projection of the relay lens 41 along the optical path covers the projection of the fly-eye lens 30, so that the light exiting the fly-eye lens 40 can enter the relay lens 41 as much as possible without increasing the overall size of the projection optical machine. That is, as viewed along the optical path, the outer edge of the fly-eye lens 30 does not exceed the outer edge of the relay lens 41. For example, when both are circular optical elements, the diameters of the two are equal, or the diameter of the relay lens 41 is larger than that of the fly-eye lens 30. In order to maximize the utilization of the light beam and reduce stray light as much as possible while keeping the size of the projection optical machine unchanged, the diameter of the relay lens 41 is as close as possible to the diameter of the fly-eye lens 30.

[0058] In order to further reduce the stray light generated by the light exiting the fly-eye lens 40, the distance between the fly-eye lens 30 and the relay lens 41 along the optical path is as small as possible. In some embodiments, the relay lens 41 is arranged immediately adjacent to the fly-eye lens 30, that is, the light exiting the fly-eye lens 30 directly enters the relay lens 41 without passing through other optical elements such as a mirror. In this embodiment, the distance between the relay lens 41 and the fly-eye lens 30 is preferably not less than 0.1 mm, so that while the stray light caused by the light exiting the fly-eye lens 40 is minimized, the relay lens 41 and the fly-eye lens 30 are kept at a certain distance to avoid interference, especially to avoid interference that may occur due to thermal deformation during long-term use.

[0059] Although the back focal plane of the light source lens group 20 is not on the fly-eye lens 30, which can reduce the thermal damage to the fly-eye lens 30, if the distance between the back focal plane and the fly-eye lens 30 is too large, it may affect the light flux of the fly-eye lens 30. Preferably, the distance between the back focal plane and the fly-eye lens 30 is 0.8-1.5 mm, such as 0.8 mm, 0.9 mm, 1.0 mm, 1.2 mm, 1.4 mm or 1.5 mm. In this way, the light beam power density received by the entrance surface of the fly-eye lens 30 can be reduced, that is, the light energy density on the fly-eye lens 30 can be reduced to at least 17% of that on the conjugate image surface, or even to 8% of that on the conjugate image surface, thereby effectively reducing the thermal damage, while the light flux entering the fly-eye lens 30 remains essentially unchanged, the light efficiency remains essentially unchanged, and the quality of the projection image is ensured.

[0060] Optionally, in order to increase the number of conjugate points on the back focal plane of the light source lens group 20 and the entrance surface of the light homogenizing rod 22, thereby increasing the number of light spots projected onto the fly-eye lens 30 and improving the projection effect of the entire projection optical machine, in a preferred embodiment of the present application, the number of reflections of the light beam exiting the converging optical unit 21 within the light homogenizing rod 22 is greater than or equal to 3 times, such as 3, 4 or 5 times, etc.

[0061] In a preferred embodiment, the light source optical unit 20 further comprises a diffusion sheet 24, which can be arranged at at least one of the following positions, as shown in Figure 1 , Figure 2 , Figure 5

[0062] (1) The diffusion sheet 24 is arranged between the homogenizing rod 22 and the converging optical unit 21, and is close to or attached to the incident surface of the homogenizing rod 22, i.e. the distance between the diffusion sheet 24 and the converging optical unit 21 is greater than the distance between the diffusion sheet 24 and the homogenizing rod 22 in the light path, or in other words, the diffusion sheet 24 is closer to the homogenizing rod 22 than the converging optical unit 21, such as the diffusion sheet 24 is arranged close to the incident surface of the homogenizing rod 22, and of course, the two can also be left a certain distance.

[0063] (2) The diffusion sheet 24 is arranged between the homogenizing rod 22 and the collimating optical unit 23, and is close to or attached to the exit surface of the homogenizing rod 22, i.e. the distance between the diffusion sheet 24 and the collimating optical unit 23 is greater than the distance between the diffusion sheet 24 and the homogenizing rod 22 in the light path, or in other words, the diffusion sheet 24 is closer to the homogenizing rod 22 than the collimating optical unit 23, such as the diffusion sheet 24 is arranged close to the exit surface of the homogenizing rod 22, and of course, the two can also be left a certain distance, as shown in Figure 1 , Figure 2

[0064] (3) The diffusion sheet 24 is arranged between the collimating optical unit 23 and the compound eye lens 30, and is close to the incident surface of the compound eye lens 30, i.e. the distance between the diffusion sheet 24 and the collimating optical unit 23 is greater than the distance between the diffusion sheet 24 and the compound eye lens 30 in the light path, or in other words, the diffusion sheet 24 is closer to the compound eye lens 30 than the collimating optical unit 23, such as the diffusion sheet 24 is arranged close to the incident surface of the compound eye lens 30, and of course, the two can also be left a certain distance.

[0065] Specifically, the diffusion sheet 24 can be arranged at only one of the above positions, such as the diffusion sheet 24 is arranged at the incident surface of the homogenizing rod 22, the exit surface of the homogenizing rod, or the incident surface of the compound eye lens 30. The diffusion sheet 24 can also be arranged at two of the above positions, such as the diffusion sheet 24 is arranged at the incident surface and the exit surface of the homogenizing rod 22, or the incident surface of the homogenizing rod 22 and the incident surface of the compound eye lens 30 (as shown in Figure 5 Of course, the diffusion sheet 24 can also be arranged at all three positions. By adding the diffusion sheet, the coherence of the laser beam can be reduced, and the speckle phenomenon can be eliminated, thereby improving the projection effect of the projection light machine.

[0066] ​​Regardless of which way the diffusion plate 24 is arranged, the diffusion plate 24 at each location can be a fixed diffusion plate, or a rotatable diffusion plate, or some are fixed diffusion plates and some are rotatable diffusion plates. Among them, the rotatable diffusion plate refers to the diffusion plate 24 itself being non-fixed and rotatable in the plane where it is located, such as rotating around its own axis. In this way, in operation, better spot dissipation can be achieved through the rotation of the diffusion plate 24. In each of the above embodiments, regardless of how the diffusion plate 24 is arranged, the back focal plane of the light source lens group 20 is not located on the diffusion plate 24.

[0067] The above prism group 50 can only include one optical prism, or can include two combined optical prisms. When including two optical prisms, it can be arranged in the structure as shown in Figure 1 The light beam reflected by the DMD module 60 enters the latter optical prism again, is transmitted into the other optical prism, and then exits the projection light machine, and then enters the projection lens (described below); or the light beam from the relay lens group 40 first enters one optical prism and then is transmitted into the other optical prism, and then enters the DMD module 60 (in this embodiment, the DMD module and the relay lens group are respectively arranged on the two sides adjacent to the prism group, and the projection lens is arranged on the side adjacent to the two sides), the light beam reflected by the DMD module 60 enters the latter optical prism again and is reflected out of the projection light machine, and then enters the projection lens.

[0068] In some projection light machines, a mirror (not shown in the figure) is also included, and the mirror is arranged between two adjacent optical elements from the light rod 22 to the relay lens group 40 in the optical path, such as being arranged between the light rod 22 and the collimating optical unit 23, or being arranged between the collimating optical unit 23 and the fly-eye lens 30. Of course, the mirror can also be arranged between two adjacent optical elements in the collimating optical unit 23, or between two adjacent relay lenses in the relay lens group 40. By arranging the mirror, the size of the projection light machine in the direction of the optical axis of the light rod 22 can be reduced.

[0069] It can be understood that the projection light machine 100 also includes a light machine shell (not shown in the figure), and the laser light source 10, the light source lens group 20, the fly-eye lens 30, the relay lens group 40, the prism group 50, and the DMD module 60 are respectively mounted on the light machine shell.

[0070] The present application also provides an electronic device, which can be a projection device or a measuring device, such as a projector used in the fields of conference and teaching, or a three-dimensional measuring device used in industrial applications. Figure 1 The electronic device comprises the projection lens 200 and the projection light engine 100 according to any one of the above embodiments, and the projection lens 200 is installed on the light exit side of the projection light engine 100, specifically, on the lens hole of the light engine shell.

[0071] Those skilled in the art can understand that the above preferred schemes can be freely combined and superimposed without conflict.

[0072] It should be understood that the above embodiments are only exemplary and not limiting, and those skilled in the art can make various obvious or equivalent modifications or replacements to the above details without departing from the essential principles of the present application, which shall be included in the scope of the claims of the present application.

Claims

1. A projection optical engine, comprising a laser light source, a light source lens group, a relay lens group, a prism group, and a DMD module arranged sequentially along an optical path, characterized in that, It also includes a compound eye lens disposed along the optical path between the light source lens group and the relay lens group. The light source lens assembly includes a converging optical unit, a homogenizing rod, and a collimating optical unit arranged sequentially along the optical path. The projection of the converging optical unit along the optical path covers the projection of the laser light source. The incident surface of the homogenizing rod is located on the back focal plane of the converging optical unit. A distance is left between the collimating optical unit, the homogenizing rod, and the compound eye lens along the optical path. The relay lens group includes a relay lens, which is disposed adjacent to the compound eye lens in the optical path, forming an air gap between them, and the projection of the relay lens along the optical path covers the projection of the compound eye lens. Wherein, the back focal plane of the light source lens group is not on the compound eye lens, nor on the relay lens, so that the light beam emitted by the laser light source is processed by the light source lens group and then illuminates the compound eye lens in the form of a light spot. The light beam processed by the compound eye lens enters the relay lens group and the prism group in sequence and then illuminates the DMD module. After being reflected by the DMD module, it is emitted again from the projection optical engine through the prism group.

2. The projection optical engine according to claim 1, characterized in that, In the optical path, the back focal plane of the light source lens group is located upstream of the incident surface of the compound eye lens.

3. The projection optical engine according to claim 2, characterized in that, In the optical path, the exit surface of the homogenizing rod is disposed on the front focal plane of the collimating optical unit.

4. The projection optical engine according to claim 2, characterized in that, In the optical path, the distance between the exit surface of the homogenizing rod and the collimating optical unit is greater than the focal length of the collimating optical unit.

5. The projection optical engine according to claim 1, characterized in that, The back focal plane of the light source lens group is located between the compound eye lens and the relay lens.

6. The projection optical engine according to claim 5, characterized in that, The distance between the exit surface of the homogenizing rod and the collimating optical unit is less than the focal length of the collimating optical unit.

7. The projection optical engine according to claim 1, characterized in that, The collimation angle of the light output by the collimating optical unit is not greater than the maximum incident angle of the light from the compound eye lens.

8. The projection optical engine according to claim 1, characterized in that, In the projection along the optical path, the projection of the relay lens covers the projection of the compound eye lens, and the distance between the relay lens and the compound eye lens is not less than 0.1 mm.

9. The projection optical engine according to claim 1, characterized in that, The distance between the incident surface of the compound eye lens and the back focal plane of the light source lens group is 0.8~1.5mm; the emitted beam of the converging optical unit is reflected by the homogenizing rod more than or equal to 3 times.

10. The projection optical engine according to claim 1, characterized in that, The light source mirror assembly further includes a diffuser, which is disposed at at least one of the following locations: (1) The light-diffusing rod is located between the light-diffusing rod and the converging optical unit, and is close to or attached to the incident surface of the light-diffusing rod; (2) The light-diffusing rod is located between the light-diffusing rod and the collimating optical unit, and is close to or attached to the exit surface of the light-diffusing rod; (3) Between the collimating optical unit and the compound eye lens, and near the incident surface of the compound eye lens.

11. The projection optical engine according to any one of claims 1-10, characterized in that, It also includes a reflector, wherein the reflector is disposed between two adjacent optical elements in the optical path from the homogenizing rod to the relay lens group, so as to reduce the size of the projection optical engine in the direction of the optical axis of the homogenizing rod.

12. An electronic device, characterized in that, It includes a projection lens and a projection optical engine as described in any one of claims 1-11, wherein the projection lens is mounted on the light-emitting side of the projection optical engine.

13. The electronic device according to claim 12, characterized in that, The electronic device is a projection device or a measuring device.

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