Light combining element, ray machine assembly and projection equipment

Abstract

The invention relates to a light combining element, a light machine assembly and projection equipment, the light combining element is used for combining a first light source emitting a first light beam and a second light source emitting a second light beam, the optical expansion amount of the first light beam is smaller than that of the second light beam, and the light combining element is provided with a light incoming surface, a reflecting surface and a light outgoing surface, and the first light beam enters the light combining element from one side of the light incident surface, reaches the reflecting surface after being reflected for multiple times, is reflected to the light emergent surface through the reflecting surface, is emitted, and enters a post-stage light path after being combined with the second light beam. Two light beams with different optical expansion amounts are combined, the lighting effect is effectively improved, the structure is simple, and the cost is low. When the light combination element is applied to the projection equipment, the display effect of the projection equipment can be remarkably improved.

Description

Technical Field

[0001] This application relates to the field of projection display technology, and particularly to a light combining element, an optical engine assembly, and a projection device. Background Art

[0002] As a new generation of projection light source, laser has the characteristics of high brightness, good monochromaticity, and small emission angle. However, due to the high coherence of laser, projection products using laser usually suffer from speckle phenomenon, which affects the consumer experience. In addition, the high cost of laser also limits the application scenarios of laser technology. As an incoherent light source, light-emitting diode (LED) has the advantages of low cost and no speckle. How to combine the advantages of LED and laser for light combining has become an important research topic in the projection industry. Summary of the Invention

[0003] The purpose of this application is to provide a light combining element, an optical engine assembly, and a projection device, which can combine two beams with different optical expansion amounts, effectively improve the light efficiency, and enhance the display effect of the projection device.

[0004] In a first aspect, an embodiment of this application provides a light combining element for combining a first light source emitting a first beam and a second light source emitting a second beam, and the optical expansion amount of the first beam is less than that of the second beam. The light combining element has an incident light surface, a reflection surface, and an exit light surface. The first beam enters the light combining element from one side of the incident light surface, undergoes multiple reflections and then reaches the reflection surface, is reflected by the reflection surface to the exit light surface and exits, and converges with the second beam and then enters the subsequent optical path.

[0005] In a possible implementation manner, the light combining element is a columnar structural member, the incident light surface and the reflection surface are located at two axial ends of the light combining element, and the exit light surface intersects with the reflection surface.

[0006] In a possible implementation manner, the incident light surface is perpendicular to the axis of the light combining element, the normal of the reflection surface is set at a preset angle with respect to the axis of the light combining element, and the value range of the preset angle is 45°±10°.

[0007] In a possible implementation manner, the surface roughness of the reflection surface is 0.010μm - 0.015μm, and the first beam undergoes total reflection on the reflection surface and then exits from the exit light surface.

[0008] In a possible implementation manner, the incident angle α when the first beam enters the incident light surface satisfies the following condition: 0 < α < 5°.

[0009] In a possible implementation manner, the reflection surface is provided with a reflection film.

[0010] In a possible implementation, the light-emitting surface is located on the outer peripheral side of the light-combining element, and the positive projection of the reflecting surface on the outer peripheral side of the light-combining element coincides at least partially with the light-emitting surface.

[0011] In a possible implementation, the optical axis of the second light beam is perpendicular to the light-emitting surface, and the second light beam forms a first aperture D on the plane where the light-emitting surface is located. The first light beam forms a second aperture d on the light-emitting surface, and the following condition is satisfied: D / d > 2.

[0012] In a possible implementation, the light-combining element includes a first body part and a second body part connected in sequence. The first body part includes a light-incident surface, and the second body part includes a reflecting surface and a light-emitting surface.

[0013] In a possible implementation, the cross-sectional shape of the first body part is circular or rectangular. The length of the first body part along the axial direction is L, and the diameter of the first body part or the diameter of the circumscribed circle of the cross-section is S, and the following condition is satisfied: 10 < L / S < 50.

[0014] In a second aspect, an optical machine assembly provided by an embodiment of the present application includes: a first light source for emitting a first light beam; a second light source for emitting a second light beam, where the optical expansion amount of the first light beam is less than that of the second light beam; and the light-combining element as described above. The first light beam enters the light-combining element from one side of the light-incident surface, undergoes multiple reflections and then reaches the reflecting surface, is reflected by the reflecting surface to the light-emitting surface and exits, and converges with the second light beam and then enters the subsequent optical path.

[0015] In a possible implementation, the optical machine assembly further includes: a speckle-dissipating element disposed on the optical path of the first light beam for suppressing the speckle of the first light beam. The first light beam passes through the speckle-dissipating element and then enters the light-combining element from the light-incident surface.

[0016] In a possible implementation, the optical machine assembly further includes: a speckle-dissipating element disposed on the optical path of the first light beam for transmitting and suppressing the speckle of the first light beam. The first light beam passes through the speckle of the speckle-dissipating element and then enters the light-combining element from the light-incident surface.

[0017] In a possible implementation, the optical machine assembly further includes: a first lens assembly disposed between the first light source and the speckle-dissipating element for focusing the first light beam on the speckle-dissipating element; a light homogenizing assembly disposed on the side of the light-emitting surface of the light-combining element for homogenizing and shaping the converged first light beam and second light beam; a second lens assembly and an image display device. The second lens assembly is disposed between the light homogenizing assembly and the image display device for converging the homogenized and shaped light beam to the image display device to form an illumination spot; and a lens for projecting the image information emitted from the image display device onto the screen.

[0018] In a third aspect, an embodiment of the present application provides a projection device, including: the optical engine component as described above.

[0019] The light combining element, optical engine component and projection device provided by the embodiments of the present application. The light combining element is used to combine a first light source emitting a first light beam and a second light source emitting a second light beam, and the optical extension amount of the first light beam is less than that of the second light beam; the light combining element has an incident light surface, a reflection surface and an exit light surface arranged in sequence along the optical path direction. The first light beam enters the light combining element from one side of the incident light surface, undergoes multiple reflections and then reaches the reflection surface, is reflected by the reflection surface to the exit light surface and exits, and converges with the second light beam and then enters the subsequent optical path. Thus, two light beams with different optical extension amounts are combined by one light combining element, effectively improving the light efficiency, and the structure is simple and the cost is low. Applying this light combining element to a projection device can significantly improve the display effect of the projection device. Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings. In addition, in the drawings, the same components use the same reference numerals, and the drawings are not drawn to actual scale.

[0021] Figure 1 Showing a schematic optical path structure diagram of the light combining element provided by the embodiment of the present application;

[0022] Figure 2 Showing Figure 1 A schematic structural diagram of a light combining element shown;

[0023] Figure 3 Showing Figure 1 A schematic structural diagram of another light combining element shown;

[0024] Figure 4 Showing a schematic structural diagram of the projection device provided by the embodiment of the present application;

[0025] Figure 5 Showing Figure 4 A schematic structural diagram of a light homogenizing component of a projection device shown;

[0026] Figure 6 Showing Figure 4 A schematic structural diagram of another light homogenizing component of the projection device shown.

[0027] Explanation of the Reference Numerals:

[0028] 1. First light source;

[0029] 2. Second light source;

[0030] 3. Light combining element; 31. Light incident surface; 32. Light output surface; 33. Reflective surface; 3a. First body part; 3b. Second body part; 34. Adhesive layer; 4. Speckle dissipation element; 5. First lens assembly;

[0031] 6. Light homogenizing assembly; 61. Fly-eye lens; 62. Third lens assembly; 63. Square bar; 7. Second lens assembly;

[0032] 8. Image display device; 9. Lens. Detailed implementation manners

[0033] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are some but not all of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0034] As Figure 1 shown, an embodiment of the present application provides a light combining element 3 for combining the first light source 1 emitting a first light beam and the second light source 2 emitting a second light beam, and the optical expansion amount of the first light beam is less than that of the second light beam. Optionally, the first light source 1 is a narrow-spectrum laser, including any one of a red laser, a green laser, and a blue laser. Optionally, the second light source 2 is a wide-spectrum light-emitting diode (LED). Of course, the first light source 1 and the second light source 2 may also be other different light sources, which will not be elaborated herein.

[0035] In the related art, there are two ways to combine light by combining the respective advantages of LEDs and lasers: One is to use the different spectra of the two light sources and use a dichroic sheet for light combination. Since the spectrum of the laser is included in the wide spectrum of the LED, if spectrum combination is used, the LED will lose the light in the overlapping region with the laser, resulting in a very low overall light efficiency. Under the existing mature and stable process conditions, the transition region (T90%-T10%) of the dichroic sheet generally reaches about 25 nm, and thus the overall light efficiency will become even lower. The other is to use a regional diaphragm, the surface properties of the central region of which are different from those of other regions. For example, the central region reflects and other regions transmit. By using the characteristic that the optical expansion amount of the laser is much smaller than that of the LED, the laser and the LED light are combined into one path. This way will cause the LED to lose a part of the light in the central region.

[0036] In view of this, the light combining element 3 in the embodiment of the present application has a light incident surface 31, a reflection surface 33 and a light exit surface 32. The first light beam enters the light combining element 3 from one side of the light incident surface 31, undergoes multiple reflections and then reaches the reflection surface 33, is reflected by the reflection surface 33 to the light exit surface 32 for emission, and converges with the second light beam and then enters the subsequent optical path. Optionally, the subsequent optical path is the optical path that the first light beam and the second light beam enter subsequently after convergence, and may include optical elements such as a condenser lens, a light homogenizing component, an image display device and a lens.

[0037] In this embodiment, the first light source 1 is a laser with a small optical extension amount, and the uniformity of the laser itself is poor. The first light beam emitted by the first light source 1 enters the interior of the light combining element 3 from the light incident surface 31 of the light combining element 3, undergoes multiple reflections and then reaches the reflection surface 33 of the light combining element 3, is reflected by the reflection surface 33 to the light exit surface 32 of the light combining element 3 for emission. After the first light beam undergoes multiple reflections in the light combining element 3, its uniformity is effectively improved.

[0038] The second light source 2 is a light emitting diode with a wide spectrum. The second light source 2 is located on one side of the light combining element 3. In the second light beam emitted by the second light source 2, most of the light beams do not pass through the light combining element 3, but directly converge with the first light beam homogenized by the light combining element 3, without light transmittance loss; a small part of the light beams in the second light beam pass through the light combining element 3, and then are emitted from the light exit surface 32 and converge with the first light beam homogenized by the light combining element 3 into a beam of light. This small part of the second light beam will lose a small amount of light transmittance after passing through the light combining element 3. Compared with the optical extension amount light combining scheme in the related art, since most of the light beams in the second light beam do not pass through the light combining element 3, the light transmittance loss is relatively small, thereby effectively improving the overall light efficiency after light combination.

[0039] The light combining element 3 provided in the embodiment of the present application is used to combine the first light source 1 emitting the first light beam and the second light source 2 emitting the second light beam, and the optical extension amount of the first light beam is less than that of the second light beam. The light combining element 3 has a light incident surface, a reflection surface and a light exit surface sequentially arranged along the optical path direction; the first light beam enters the light combining element 3 from one side of the light incident surface 31, undergoes multiple reflections and then reaches the reflection surface 33, is reflected by the reflection surface 33 to the light exit surface 32 for emission, and converges with the second light beam and then enters the subsequent optical path. Thus, two light beams with different optical extension amounts are combined by one light combining element, effectively improving the light efficiency, and having a simple structure and low cost.

[0040] In some embodiments, the light combining element 3 is a columnar structural member. The light incident surface 31 and the reflection surface 33 are located at the axial two ends of the light combining element 3, and the light output surface 32 intersects with the reflection surface 33. The light incident surface 31 and the reflection surface 33 being located at the axial two ends of the light combining element 3 can elongate the reflection optical path and improve the uniformity of the first light beam. The light output surface 32 intersecting with the reflection surface 33 can enable most of the first light beam reflected from the reflection surface 33 to be output from the light output surface 32, thereby improving the light transmittance of the first light beam.

[0041] In some embodiments, the light incident surface 31 is arranged perpendicular to the axis of the light combining element 3, and the normal of the reflection surface 33 is arranged at a preset angle with respect to the axis of the light combining element 3, and the value range of the preset angle is 45°±10°.

[0042] In one example, as Figure 2 shown, the light combining element 3 is a solid columnar structural member, and its cross-sectional shape is rectangular or circular. The light incident surface 31 is an end surface of the light combining element 3 along its own axis, and the normal of the reflection surface 33 is arranged at a preset angle θ with respect to its own axis. The first light beam enters the interior of the light combining element 3 from the light incident surface 31, undergoes multiple reflections along the columnar structure, and then reaches the reflection surface 33 of the light combining element 3. Since the reflection surface 33 is inclined with respect to the light incident surface 31, the first light beam is reflected after passing through the reflection surface 33 and is output from the light output surface 32. Further preferably, θ = 45°, and the reflection surface 33 is equivalent to a plane mirror, which directly outputs the first light beam incident on the reflection surface 33 after adjusting its direction by 90°. Such a setting can reduce the overall structural size of the light combining element 3. Considering the processing accuracy of the light combining element 3, the value range of the preset included angle θ is 45°±10°. On the one hand, it can meet the processing accuracy requirements of the light combining element 3 and reduce the manufacturing cost. On the other hand, it can ensure that the vast majority of the first light beam can be output from the light output surface.

[0043] In some embodiments, the surface roughness of the reflection surface 33 is 0.010 μm to 0.015 μm, and the first light beam undergoes total reflection after passing through the reflection surface 33 and is output from the light output surface 32. In one example, the surface roughness of the reflection surface 33 is 0.012 μm. The roughness of the reflection surface 33 is small and the surface is relatively smooth, which can enable the first light beam to undergo total reflection when reaching the reflection surface 33, reduce the loss of the light transmittance of the first light beam, and further improve the light combining efficiency. In addition, a small part of the second light beam can directly pass through the reflection surface 33 to reach the light output surface 32 and then be output from the light output surface 32, and the loss of the light transmittance is small and can even be ignored.

[0044] Further, in order to make the first light beam totally reflected by the reflecting surface 33, the incident angle α of the first light beam when entering the light incident surface 31 satisfies the following condition: 0 < α < 5°. By limiting the incident angle of the first light beam, the light transmittance loss of the first light beam can be further reduced, thereby improving the light efficiency of the combined light.

[0045] According to the calculation formula of the refraction law, the incident angle α = θ - arcsin(1 / n), where n is the refractive index of the light combining element 3. Optionally, the material of the light combining element 3 is generally optical glass, optical crystal, special optical material, etc., and the refractive index is generally 1.4 - 1.6. In one example, as Figure 2 shown, n = 1.45, θ = 45°, 0 < α < 1.4°. Since the incident angle α of the first light beam when entering the light incident surface 31 is small, it is not easy to control, and the surface roughness requirement for the reflecting surface 33 is relatively high, which limits the feasibility of the first light beam being totally reflected by the reflecting surface 33, and the operation cost is relatively high.

[0046] To this end, in some embodiments, a reflective film is provided on the reflecting surface 33. The reflective film can be a dielectric film or a metal film with a high refractive index. In one example, the material of the reflective film is titanium dioxide TiO2, which is formed on the reflecting surface 33 by spraying or coating, thereby improving the reflectivity of the reflecting surface 33, so that as much of the first light beam as possible is reflected to the light exit surface 32 after reaching the reflecting surface 33. With such a setting, the attention to the incident angle of the first light beam and the roughness of the reflecting surface 33 can be reduced, and the manufacturing cost of the light combining element 3 and its assembly cost with the first light source 1 can be lowered.

[0047] In some embodiments, the light exit surface 32 is located on the outer peripheral side of the light combining element 3, and the orthographic projection of the reflecting surface 33 on the outer peripheral side of the light combining element 3 coincides with at least a part of the light exit surface 32. When the cross-sectional shape of the light combining element 3 is rectangular, the light exit surface 32 is a side plane of the light combining element 3; when the cross-sectional shape of the light combining element 3 is circular, the light exit surface 32 is a partial arc surface of the light combining element 3. As Figure 2 shown, the orthographic projection of the reflecting surface 33 on the outer peripheral side of the light combining element 3 completely coincides with the light exit surface 32. With such a setting, on the one hand, it can ensure that most of the first light beam reflected from the reflecting surface 33 can exit from the light exit surface 32, and on the other hand, it can reduce the occupied space of the subsequent optical path, thereby reducing the overall volume.

[0048] It can be understood that the area of the light exit surface 32 can also be larger than the orthographic projection area of the reflecting surface 33 on the outer peripheral side of the light combining element 3. At this time, the outgoing light beam after the first light beam reaches the reflecting surface 33 may overlap with the incident light beam before reaching the reflecting surface 33, which can be flexibly adjusted according to the actual application scenario and will not be elaborated here.

[0049] In some embodiments, the optical axis of the second light beam is perpendicular to the light-emitting surface 32, and the second light beam forms a first aperture D on the plane where the light-emitting surface 32 is located. The first light beam forms a second aperture d on the light-emitting surface 32, and the following condition is satisfied: D / d > 2. As Figure 1 shown, the optical axis of the second light beam is perpendicular to the light-emitting surface 32, which can reduce the occupied space of the subsequent optical path and thus reduce the overall volume. In addition, the second light beam forms a first aperture of D on the plane where the light-emitting surface 32 is located, and the first light beam forms a second aperture of d on the light-emitting surface 32. Setting D / d > 2 can ensure that the first light beam emitted from the light combining element 3 completely converges with the second light beam, improving the overall light efficiency of light combination.

[0050] In some examples, the light combining element 3 includes a first body portion 3a and a second body portion 3b connected in sequence. The first body portion 3a includes a light-incident surface 31, and the second body portion 3b includes a reflecting surface 33 and a light-emitting surface 32. The plane where the connection between the first body portion 3a and the second body portion 3b is located intersects the edges of the reflecting surface 33 and the light-emitting surface 32.

[0051] Optionally, the cross-sectional shapes and areas at the connection between the first body portion 3a and the second body portion 3b are the same. For example, the cross-sectional shape at the connection between the first body portion 3a and the second body portion 3b is rectangular or circular. In one example, as Figure 3 shown, the light combining element 3 is an overall solid columnar structural member, which includes a first body portion 3a and a second body portion 3b. In another example, a partial structure of the first body portion 3a near the light-incident surface side is a columnar structural member with a hollow interior, which is used to reduce the light transmittance loss of the first light beam in the light combining element 3; the part of the first body portion 3a near the second body portion 3b is still a solid structure, and the second body portion 3b is also a solid columnar structural member, which is used to reduce the light transmittance loss when the second light beam passes through the light combining element 3. Optionally, the first body portion 3a is a rectangular column, and its cross-sectional shape is rectangular, and the second body portion 3b is a triangular prism. Optionally, the first body portion 3a is a circular column, and its cross-sectional shape is circular, and the second body portion 3b is a columnar body with a part of its structure obliquely cut off, and the shape of its reflecting surface is circular or elliptical.

[0052] Furthermore, the first body portion 3a includes a light incident surface 31, the second body portion 3b includes a reflecting surface 33 and a light exit surface 32. The first light beam enters the first body portion 3a from the light incident surface 31, undergoes multiple reflections and then reaches the reflecting surface 33 of the second body portion 3b. After being reflected by the reflecting surface 33, it is reflected to the light exit surface 32 and exits. A small portion of the second light beam passes through the second body portion 3b, and together with another portion of the second light beam that does not pass through the second body portion 3b, it converges with the first light beam that is homogenized by the light combining element 3 and then exits. The first body portion 3a and the second body portion 3b are bonded together by an adhesive layer 34. The adhesive layer 34 is made of a light-transmissive material and has a relatively thin thickness. With such a setting, on the one hand, the light transmittance loss of the first light beam and the second light beam passing through the light combining element can be reduced. On the other hand, since the processing accuracy requirements for the reflecting surface 33 of the second body portion 3b are relatively high. For example, a dielectric film or a metal film with a high refractive index can be provided on the surface of the reflecting surface 33, or it can remain smooth without coating. The light combining element 3 is divided into two parts for separate processing, and only the processing accuracy requirements for the second body portion 3b are relatively high, thereby reducing the overall manufacturing cost.

[0053] Furthermore, the cross-sectional shape of the first body portion 3a is circular or rectangular. The length of the first body portion 3a along the axial direction is L, and the diameter of the first body portion 3a or the diameter of the circumscribed circle of the cross-section is S, and the following condition is satisfied: 10 < L / S < 50. With such a setting, the reflection optical path of the first light beam can be lengthened, and the uniformity of the first light beam can be further improved.

[0054] As Figure 4 shown, an optical machine assembly provided by an embodiment of the present application includes: a first light source 1, a second light source 2, and the light combining element 3 as described above.

[0055] The first light source 1 is used to emit a first light beam. Optionally, the first light source 1 is a narrow-spectrum laser, including any one of a red laser, a green laser, and a blue laser. The laser beam has the characteristics of high brightness, good monochromaticity, and a small emission angle, and at the same time has high coherence. The high coherence of the laser will cause the speckle effect in laser projection display. The speckle effect means that when a coherent light source irradiates an optically rough surface such as a wall, paper, or ground glass whose average roughness is greater than the order of magnitude of the laser wavelength, the scattered light interferes in space due to a constant phase difference, the same light wave frequency, and the same vibration direction. Some parts interfere constructively, and some parts interfere destructively, resulting in a random spatial light intensity distribution, presenting a granular structure. Eventually, the result is that bright and dark spots, that is, speckles, appear on the screen. These unfocused spots appear to flicker to the human eye, which is easy to cause discomfort after long-term viewing and seriously affects the quality of the projection image, reducing the user's viewing experience.

[0056] The second light source 2 is used to emit a second light beam, and the optical extent of the first light beam is less than that of the second light beam. Optionally, the second light source 2 is a wide-spectrum light-emitting diode (LED).

[0057] The light combining element 3 combines the first light beam and the second light beam with different optical extents on one side of the light-emitting surface 32 of the light combining element 3. Specifically, the first light beam enters the light combining element 3 from one side of the light-incident surface 31 of the light combining element 3, undergoes multiple reflections and then reaches the reflection surface 33, is reflected by the reflection surface 33 to the light-emitting surface 32 for emission, and enters the subsequent optical path after converging with the second light beam.

[0058] Furthermore, the optical engine assembly further includes a speckle-reducing element 4. The speckle-reducing element 4 is disposed on the optical path of the first light beam and is used to suppress the speckle of the first light beam. After passing through the speckle-reducing element, the first light beam enters the light combining element 3 from the light-incident surface 31.

[0059] The speckle-reducing element 4 can be a static optical element or a dynamic optical element. In one example, the speckle-reducing element 4 is a diffuser wheel, the surface of which is a rough surface. The diffuser wheel is coaxially arranged with a motor, and the motor drives the diffuser wheel to rotate around the central axis. When the laser beam passes through the diffuser wheel, light beams with different angles are generated, and the superposition of the light beams with different angles presents a visual effect of speckle elimination. In another example, the speckle-reducing element 4 is a vibrating diffuser sheet, and the vibrating diffuser sheet is driven by a vibration controller to vibrate in any one of the XY plane, YZ plane, and XZ plane according to a preset trajectory to improve the speckle-reducing effect of the laser beam.

[0060] Furthermore, the optical engine assembly further includes a first lens assembly 5, a light homogenizing assembly 6, a second lens assembly 7, an image display device 8, and a lens 9.

[0061] The first lens assembly 5 is disposed between the first light source 1 and the speckle-reducing element and is used to focus the first light beam on the speckle-reducing element 4. The first lens assembly 5 includes at least one lens, and the lens is a convex lens for converging light.

[0062] The light homogenizing assembly 6 is disposed on one side of the light-emitting surface 32 of the light combining element 3 and is used to homogenize and shape the combined first light beam and second light beam.

[0063] The second lens assembly 7 is disposed between the light homogenizing assembly 6 and the image display device 8 and is used to converge the homogenized and shaped light beam to the image display device 8 to form an illumination spot. The second lens assembly 7 includes at least one convex lens, and the convex lens is used to converge the parallel light beam to the image display device 8. The image display device 8 is a digital micromirror device (DMD), a reflective liquid crystal on silicon panel (LCOS), or a transmissive liquid crystal panel (LCD). The size of the illumination spot matches the size of the image display device 8, for example, both are rectangular.

[0064] The lens 9 is used to project the image information emitted from the image display device onto the screen.

[0065] In this embodiment, the first light source 1 is a laser. The collimated first light beam emitted by it is focused on the incident surface 31 of the light combining element 3 after passing through the first lens group 5. And a dynamic speckle reducing element 4 is placed at the incident surface 31 of the light combining element 3 for transmitting the laser beam and suppressing the speckle of the laser beam. After the first light beam is reflected multiple times inside the light combining element 3, it is reflected by the reflecting surface 33 to the exit surface 32 of the light combining element 3, and is combined with the second light beam and then incident on the light homogenizing component 6. Among them, the second light source is an LED, and the second light beam emitted by it includes a part passing through the light combining element and a part not passing through the light combining element. After the combined first light beam and second light beam are homogenized by the light homogenizing component 6, they are focused on the image display device 8 by the second lens group 7, and then projected onto the screen after being magnified by the lens 9 to form a bright picture.

[0066] In some embodiments, the light homogenizing component 6 includes a fly-eye lens 61. As Figure 5 shown, the fly-eye lens 61 is formed by a combination of a series of small lenses. To achieve uniform illumination, two columns of fly-eye lens arrays need to be arranged in parallel. The focal points of the individual small unit lenses in the first column of fly-eye lens arrays coincide with the centers of the corresponding small unit lenses in the second column of fly-eye lens arrays. The optical axes of the two columns of fly-eye lenses are parallel to each other. A condenser lens is placed behind the second column of fly-eye lenses, and an illumination screen is placed on the focal plane of the condenser lens to form a uniform illumination system, enabling the double-row fly-eye lens array to obtain high light energy utilization and large-area uniform illumination, and having broad application prospects in the field of projection display.

[0067] The optical path principle of the fly-eye lens 61 is as follows: The light beam parallel to the optical axis is focused at the center of the second lens after passing through the first lens. The first row of fly-eye lenses forms multiple light sources with the light source for illumination. Each small lens of the second row of fly-eye lenses overlaps and images the multiple small lenses of the first row of fly-eye lenses on the illumination surface. Since the first row of fly-eye lenses divides the entire wide light beam of the light source into multiple thin light beams for illumination, and the vertical non-uniformity within each thin light beam range is compensated by the mutual superposition of the thin light beams in the symmetric positions, the vertical non-uniformity of the thin light beams is compensated, so that the light energy within the entire aperture is effectively and uniformly utilized. The exit light spot from the second row of fly-eye lenses is focused on the illumination screen through the condenser lens. In this way, each point on the light spot on the illumination screen is irradiated by the light rays emitted from all points of the light source. At the same time, the light beams emitted from each point on the light source also intersect and overlap within the same field of view range of the illumination light spot, so a uniform square light spot can be obtained.

[0068] In some embodiments, the light homogenizing component 6 includes a square rod 62 and a third lens assembly 63. The third lens assembly 63 is disposed between the light combining element 3 and the square rod 62. The square rod 62 is a quadrilateral prism, and its cross-section is a rectangle or a trapezoid.

[0069] As Figure 6 shown, the third lens assembly 63 includes at least one lens, and the lens is a convex lens for parallelly emitting the converged light rays after light homogenization. The square rod 62 is a quadrilateral prism, and its cross-section is a rectangle or a trapezoid.

[0070] In addition, the projection device provided by the embodiment of the present application includes the light engine assembly as described above.

[0071] The light engine assembly and the projection device provided by the embodiment of the present application include the light combining element 3 as described above. The light combining element 3 is used for combining the first light source 1 emitting the first light beam and the second light source 2 emitting the second light beam, and the optical extension amount of the first light beam is less than that of the second light beam. The light combining element 3 has an incident light surface, a reflecting surface, and an emergent light surface sequentially arranged along the optical path direction; the first light beam enters the light combining element 3 from one side of the incident light surface 31, undergoes multiple reflections and then reaches the reflecting surface 33, is reflected by the reflecting surface 33 to the emergent light surface 32 for emergence, and converges with the second light beam and then enters the subsequent optical path, where the second light beam includes a part passing through the light combining element and a part not passing through the light combining element. Thus, two light beams with different optical extension amounts are combined by one light combining element 3, effectively improving the light efficiency, and having a simple structure and low cost. Applying the light combining element 3 to the projection device can significantly improve the display effect of the projection device.

[0072] It should be noted that the "one embodiment", "embodiment", "exemplary embodiment", "some embodiments", etc. mentioned in the specification indicate that the described embodiments may include specific features, structures, or characteristics, but not necessarily every embodiment includes such specific features, structures, or characteristics. In addition, such phrases do not necessarily refer to the same embodiment. In addition, when combining specific features, structures, or characteristics with an embodiment, implementing such features, structures, or characteristics in combination with other embodiments, whether explicitly or implicitly described, is within the knowledge scope of those skilled in the art.

[0073] It should be easily understood that the terms "on...", "above...", and "over..." in the present disclosure should be interpreted in the broadest manner, so that "on..." not only means "directly on something", but also includes the meaning of "on something" with intermediate features or layers therebetween, and "above..." or "over..." not only includes the meaning of "above or over something", but may also include the meaning of "above or over something" without intermediate features or layers therebetween (i.e., directly on something).

[0074] In addition, for ease of description, the text may use spatial relative terms, such as "below", "beneath", "under", "above", "over", etc., to describe the relationship of one element or feature to other elements or features as shown in the figure. Spatial relative terms are intended to encompass different orientations of the device in use or operation other than the orientation shown in the drawings. The device may have other orientations (rotated 90 degrees or at other orientations), and the spatial relative descriptors used in the text may be interpreted accordingly.

[0075] It should be noted that in this text, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements not only includes those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A light combining element is used for combining a first light source emitting a first light beam and a second light source emitting a second light beam, and the optical expansion amount of the first light beam is less than that of the second light beam. It is characterized in that the light combining element has an incident light surface, a reflecting surface and an exit light surface. The first light beam enters the light combining element from one side of the incident light surface, undergoes multiple reflections and then reaches the reflecting surface, is reflected by the reflecting surface to the exit light surface for emission, and converges with the second light beam and then enters the subsequent optical path.

2. The optical combining element according to claim 1, wherein The light combining element is a columnar structural member. The incident light surface and the reflecting surface are located at the axial two ends of the light combining element, and the exit light surface intersects with the reflecting surface at an angle.

3. The optical combining element according to claim 2, wherein, The normal of the reflecting surface is set at a preset angle with the axis of the light combining element, and the value range of the preset angle is 45° ± 10°.

4. The optical combining element according to claim 3, wherein The surface roughness of the reflecting surface is 0.010 μm to 0.015 μm. The first light beam undergoes total reflection on the reflecting surface and then exits from the exit light surface.

5. The light combining element according to any one of claims 1-4, characterized in that, The incident angle α when the first light beam enters the incident light surface satisfies the following condition: 0 < α < 5°.

6. The optical combining element according to any one of claims 1 to 3, characterized in that, The reflecting surface is provided with a reflective film.

7. The optical combining element according to claim 2, characterized in that, The exit light surface is located on the outer peripheral side of the light combining element, and the positive projection of the reflecting surface on the outer peripheral side of the light combining element coincides with at least a part of the exit light surface.

8. The optical combining element according to claim 2, wherein The optical axis of the second light beam is perpendicular to the exit light surface. The second light beam forms a first aperture D on the plane where the exit light surface is located, and the first light beam forms a second aperture d on the exit light surface, and satisfies the following condition: D / d > 2.

9. The optical combining element according to claim 2, wherein The light combining element includes a first body part and a second body part connected in sequence. The first body part includes the incident light surface, and the second body part includes the reflecting surface and the exit light surface.

10. The optical combining element according to claim 9, characterized in that, The cross-sectional shape of the first body part is circular or rectangular. The length of the first body part along the axis is L, and the diameter of the first body part or the diameter of the circumscribed circle of the cross-section is S, and satisfies the following condition: 10 < L / S < 50.

11. An optical-mechanical component, characterized in that, Comprising: A first light source for emitting a first light beam; A second light source for emitting a second light beam, and the optical expansion amount of the first light beam is less than that of the second light beam; And The light combining element according to any one of claims 1 to 10, wherein the first light beam enters the light combining element from one side of the incident light surface of the light combining element, undergoes multiple reflections and then reaches the reflecting surface, is reflected by the reflecting surface to the exit light surface for emission, and converges with the second light beam and then enters the subsequent optical path.

12. The optical machine component according to claim 11, wherein, Further comprising: A speckle reducing element is arranged on the optical path of the first light beam for suppressing the speckle of the first light beam. The first light beam passes through the speckle reducing element and then enters the light combining element from the incident light surface.

13. The optical-mechanical component according to claim 11, wherein Further comprising: A first lens assembly is arranged between the first light source and the speckle reducing element for focusing the first light beam on the speckle reducing element; A light homogenizing assembly is arranged on the side of the exit light surface of the light combining element for homogenizing and shaping the combined first light beam and the second light beam; A second lens assembly and an image display device, the second lens assembly being disposed between the light homogenizing assembly and the image display device and configured to converge the light beam that has been homogenized and shaped onto the image display device to form an illumination spot; and a lens configured to project the image information emitted from the image display device onto a screen.

14. A projection device, characterized in that, Comprising an optical engine assembly according to any one of claims 11 to 13.

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