Optical system and projection apparatus

Abstract

The utility model discloses an optical system and a projection device, and relates to the technical field of optics, and the optical system is provided with a first light-emitting assembly, a spectroscope, a collimating lens group, a fluorescent wheel and a second light-emitting assembly which are sequentially arranged along a first direction, and the second light-emitting assembly is located at one side of the spectroscope along a second direction; the spectroscope is obliquely arranged, and a reflecting part is arranged on the side face, facing the fluorescent wheel, of the spectroscope; the fluorescent wheel comprises an aluminum substrate, the aluminum substrate is configured to rotate around a rotating shaft, the rotating axis of the aluminum substrate is parallel to the first direction, a groove is formed in the side, facing the collimating lens, of the aluminum substrate, and the inner wall face of the groove is coated with fluorescent powder; according to the optical system, the first light-emitting assembly, the spectroscope, the collimating lens group, the fluorescent wheel and the second light-emitting assembly are reasonably distributed, and the groove is formed in the aluminum substrate, so that the optical system is good in light source uniformity and high in optical efficiency.

Description

Technical Field

[0001] The utility model relates to the technical field of optics, in particular to an optical system and projection equipment. Background Art

[0002] With the recent advancement of projection technology, projectors have become widely used in homes, education, and offices. Laser projectors, in particular, have gained widespread adoption due to their advantages in brightness, lifespan, and color gamut. Laser projectors typically use a focused blue laser to excite a phosphor, generating an excitation spectrum that provides the projector's light source. Because the phosphor experiences significant heat during laser excitation, the phosphor is designed to dissipate heat using a high-speed rotating phosphor wheel. The divergence angle of the phosphor's excitation beam is also a significant factor limiting the optical efficiency of laser projection. Utility Model Content

[0003] The main purpose of the utility model is to provide an optical system and a projection device, aiming to improve the light source quality and optical efficiency of the optical system.

[0004] To achieve the above objectives, the present invention proposes an optical system comprising a first light-emitting assembly, a beam splitter, a collimating lens group, a fluorescent wheel, and a second light-emitting assembly located on one side of the beam splitter along a second direction.

[0005] The beam splitter is arranged in an inclined manner, and a reflective portion is provided on the side thereof facing the fluorescent wheel;

[0006] The fluorescent wheel includes an aluminum substrate configured to rotate around a rotation axis. The rotation axis of the aluminum substrate is parallel to the first direction. A groove is formed on a side of the aluminum substrate facing the collimating lens assembly. The inner wall of the groove is coated with fluorescent powder.

[0007] In one embodiment, the collimating lens assembly includes a first lens and a second lens arranged along a first direction;

[0008] Wherein, the surface of the first lens facing the beam splitter is a convex surface, and the second lens is arranged close to the groove of the fluorescent wheel.

[0009] In one embodiment, the groove is configured as an annular groove, and the center of the annular groove coincides with the rotation center of the aluminum substrate.

[0010] In one embodiment, the inner ring radius of the annular groove is R, and the distance between the optical axis where the collimating lens assembly is located and the rotation axis is H, where R=H.

[0011] In one embodiment, the inner wall surface of the groove is configured as a curved surface.

[0012] In one embodiment, the optical system further includes a light homogenizing component, the light homogenizing component is disposed between the beam splitter and the fluorescent wheel, and the light homogenizing component includes a third lens, a fourth lens, and a diffuser arranged along a first direction;

[0013] The third lens is disposed close to the first light-emitting component, and a side surface thereof facing the first light-emitting component is a convex surface.

[0014] In one embodiment, the optical system further includes a fan, and the fan is disposed on a side of the fluorescent wheel facing away from the collimating lens assembly and corresponding to the groove.

[0015] In one embodiment, the optical system further comprises:

[0016] a converging lens, the converging lens being located on a side of the beam splitter facing away from the second light-emitting component, and the converging lens being configured as a convex surface facing the beam splitter; and

[0017] A light-rectifying component is arranged along the second direction corresponding to the convex surface of the converging lens.

[0018] The present invention further provides a projection device, comprising an optical system, wherein the optical system comprises a first light-emitting component, a beam splitter, a collimating lens group, a fluorescent wheel, and a second light-emitting component located on one side of the beam splitter along a second direction.

[0019] The beam splitter is arranged in an inclined manner, and a reflective portion is provided on the side thereof facing the fluorescent wheel;

[0020] The fluorescent wheel includes an aluminum substrate configured to rotate around a rotation axis. The rotation axis of the aluminum substrate is parallel to the first direction. A groove is formed on a side of the aluminum substrate facing the collimating lens assembly. The inner wall of the groove is coated with fluorescent powder.

[0021] In the technical solution of the present invention, the first light-emitting component emits a blue laser along a first direction; the blue laser passes through a beam splitter that transmits blue light and reflects red and green light and enters a collimator group, the collimator group focuses the laser onto the phosphor on the inner wall of the groove of the aluminum substrate, the phosphor is excited to emit yellow light formed by a mixture of red and green light, and enters the collimator group again, the collimator group collimates the yellow light into parallel light, the parallel yellow light is reflected to a second direction by the reflective part of the beam splitter, and converges with the blue laser emitted by the second light-emitting component to form white light; by forming a groove in the area coated with phosphor on the traditional planar aluminum substrate, the coating on the inner wall of the groove has a larger excitation surface area than the conventional planar coating, so that more light can be output, the brightness is improved, and thus the optical efficiency is improved; by reasonably allocating the first light-emitting component, the beam splitter, the collimator group, the fluorescent wheel and the second light-emitting component, and forming a groove on the aluminum substrate, the light source of the optical system has good uniformity and high optical efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0023] Figure 1 A schematic structural diagram of an embodiment of an optical system provided by the present utility model;

[0024] Figure 2 for Figure 1 Schematic diagram of the structure of the fluorescent wheel.

[0025] Description of Figure Numbers:

[0026] 100. Optical system; 1. First light-emitting component; 2. Beam splitter; 3. Collimating lens group; 31. First lens; 32. Second lens; 4. Fluorescent wheel; 41. Aluminum substrate; 42. Groove; 43. Drive motor; 5. Second light-emitting component; 6. Light homogenization component; 61. Third lens; 62. Fourth lens; 63. Diffuser; 7. Fan; 8. Converging lens; 9. Light-leveling component.

[0027] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0029] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), such directional indications are only used to explain the relative position relationship, movement status, etc. between the various components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0030] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0031] The phosphor wheels 4 on the market are all made by evenly coating phosphor on a flat substrate. Since the divergence angle of the excited light beam is too large, it becomes an important factor limiting the optical efficiency of the laser projection light path.

[0032] To this end, the present invention proposes an optical system 100, which aims to improve the optical efficiency of the laser projection light path.

[0033] First, it's important to understand that phosphors are materials that emit visible light when excited by light or other forms of energy. When excited by light of a specific wavelength (such as ultraviolet or blue light), the active components within the phosphor absorb energy and enter an excited state. Subsequently, the active components return from the excited state to the ground state, releasing lower-energy photons as visible light.

[0034] See also Figure 1In one embodiment of the utility model, the optical system 100 includes a first light-emitting component 1, a beam splitter 2, a collimating lens group 3, a fluorescent wheel 4, and a second light-emitting component 5 located on one side of the beam splitter 2 along the second direction. The beam splitter 2 is arranged at an angle, and a reflective portion is provided on the side facing the fluorescent wheel 4. The fluorescent wheel 4 includes an aluminum substrate 41, which is configured to rotate around a rotation axis. The rotation axis of the aluminum substrate 41 is parallel to the first direction. A groove 42 is formed on the side of the aluminum substrate 41 facing the collimating lens group 3, and the inner wall surface of the groove 42 is coated with fluorescent powder.

[0035] The first light-emitting component 1 is used to emit a blue laser along a first direction; the spectrometer 2 can transmit blue light and the reflecting part can reflect red and green light; the collimating lens group 3 is used to focus the blue laser emitted by the first light-emitting component 1 onto the phosphor and convert the red and green divergent light excited by the phosphor into a parallel light beam; the fluorescent wheel 4 includes an aluminum substrate 41 and a driving motor 43, the driving motor 43 shaft is connected to the substrate, and is used to drive the aluminum substrate 41 to rotate so that the aluminum substrate 41 dissipates the heat generated by the excitation of the phosphor when rotating at high speed; a groove 42 is formed on the side of the aluminum substrate 41 facing the collimating lens group 3, and the inner wall surface of the groove 42 is coated with phosphor, which increases the contact area between the blue laser and the phosphor, thereby making the excitation surface area larger, outputting more light, improving the brightness, and thus improving the optical efficiency.

[0036] It should be noted that the first direction described in the present invention is parallel to the optical axis of the collimating lens group 3. The actual direction should be based on the installation direction when used (which can be up and down, left and right, front and back). This directional indication is only used to explain the relative position relationship and movement status of each component in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0037] In the technical solution of the present invention, the first light-emitting component 1 emits a blue laser along a first direction; the blue laser passes through a beam splitter 2 that transmits blue light and reflects red and green light and enters a collimator group 3, the collimator group 3 focuses the laser onto the phosphor on the inner wall of a groove 42 of an aluminum substrate 41, the phosphor is excited to emit a yellow light formed by a mixture of red and green light, and enters the collimator group 3 again, the collimator group 3 collimates the yellow light into parallel light, the parallel yellow light is reflected to a second direction by the reflecting part of the beam splitter 2, and converges with the blue laser emitted by the second light-emitting component 5 to form white light; by forming a groove 42 in the area coated with phosphor on the traditional planar aluminum substrate 41, the inner wall coating of the groove 42 has a larger excitation surface area than the conventional planar coating, so that more light can be output, the brightness is improved, and thus the optical efficiency is improved; by reasonably allocating the first light-emitting component 1, the beam splitter 2, the collimator group 3, the fluorescent wheel 4 and the second light-emitting component 5, and forming a groove 42 on the aluminum substrate 41, the light source uniformity of the optical system 100 is good and the optical efficiency is high.

[0038] In one embodiment of the present invention, the collimating lens group 3 includes a first lens 31 and a second lens 32 arranged along a first direction; wherein, the side of the first lens 31 facing the beam splitter 2 is a convex surface, and the second lens 32 is arranged close to the groove 42; by setting the side of the first lens 31 facing the beam splitter 2 as a convex surface, the blue laser emitted by the first light-emitting component 1 is focused onto the phosphor, and the red and green divergent light generated by the phosphor when excited is re-collimated into parallel light, which is convenient for subsequent optical path utilization; since the light beam excited by the phosphor after being irradiated by the laser exhibits Lambertian emission, that is, it is emitted at a divergence angle of nearly 180°, the second lens 32 is arranged close to the groove 42 to ensure that as much of the excited light beam as possible is collected, thereby improving optical efficiency.

[0039] In addition, in another embodiment of the present invention, the side of the second lens 32 facing the beam splitter 2 is also set to a convex surface, so as to obtain better focusing and collimation effects; the side of the first lens 31 facing the fluorescent wheel 4 is set to a plane and / or the side of the second lens 32 facing the fluorescent wheel 4 is set to a plane, so as to control the working distance and facilitate the installation of the various components of the optical system 100; and in order to reduce the volume of the optical system 100, in another embodiment of the present invention, the side of the first lens 31 facing the fluorescent wheel 4 is set to a convex surface and / or the side of the second lens 32 facing the fluorescent wheel 4 is set to a convex surface, so as to shorten the focal length, reduce the distance between the first lens 31 and the second lens 32 or between the first lens 31 and the beam splitter 2, and make the optical system 100 smaller.

[0040] See also Figure 2In order to produce a continuous and stable light source, in one embodiment of the present invention, the groove 42 is configured as an annular groove, the center of which coincides with the rotation axis of the aluminum substrate 41. This ensures that during the rotation of the aluminum substrate 41, a portion of the groove 42 is always located corresponding to the collimating lens group 3, thereby producing a continuous and stable light source and improving the quality of the light source. In addition, it is understood that the phosphor generates a large amount of heat during the excitation process. The other portion of the groove 42 that is not irradiated by the blue laser can dissipate heat during the rotation of the aluminum substrate 41, preventing the entire optical system 100 from overheating and causing damage to the system. The present invention does not limit the shape of the groove 42. In other embodiments, to save material, the annular groove can be configured as a square groove and located corresponding to the collimating lens group 3. The aluminum substrate is fixedly disposed so that the phosphor in the square groove is continuously excited, thereby increasing the utilization rate of the phosphor and saving costs.

[0041] See also Figure 2 In one embodiment of the present invention, the outer ring radius of the annular groove is R, the inner ring radius is r, and the distance between the optical axis of the collimating lens group 3 and the rotation axis of the aluminum substrate 41 is H, wherein (R+r) / 2=H, so that the optical axis of the collimating lens group 3 is arranged corresponding to the middle of the annular groove, which can better enable the collimating lens group 3 to focus the blue laser onto the inner wall surface of the groove 42.

[0042] It can be understood that the light beam excited by the phosphor after being irradiated by the laser shows Lambertian emission, that is, it is emitted at a divergence angle of nearly 180°, which is difficult to be collected by the light collecting device, and because the divergence angle is too large, part of the excited light beam is also difficult to be collimated. For this reason, in one embodiment of the present invention, the inner wall surface of the groove 42 is set to a curved surface, so that the excitation surface is a curved surface, and then the divergence angle of the excited phosphor is smaller than the plane Lambertian divergence angle. The reduction of this angle will increase the light path light collection efficiency, facilitate subsequent light collection design, and thus improve optical efficiency. It should be noted that the present invention does not limit the specific shape of the curved surface. It can be a circular arc surface or an aspherical surface, both of which can reduce the divergence angle.

[0043] It should be noted that phosphors come in different materials, and phosphors of different materials can emit light of different wavelengths and other colors when exposed to light of a specific wavelength. To emit light of multiple colors and improve the light source quality of the optical system 100, in one embodiment of the present invention, the inner wall surface of the groove 42 is coated with multiple layers of phosphor. Multiple phosphors can be disposed on the inner wall surface of the groove 42, and the phosphor materials with different absorption and emission characteristics are sequentially coated or deposited on the inner wall surface of the groove 42 to form a multilayer structure. Each layer of phosphor material absorbs light of a specific wavelength and emits fluorescence of a specific wavelength. Furthermore, this multilayer structure allows different phosphors in the same location of the groove 42 to be excited, allowing the phosphor wheel 4 to simultaneously generate light of different wavelengths (i.e., different colors), facilitating subsequent light integration and improving the light source quality of the optical system 100. Furthermore, in another embodiment of the present invention, the phosphor layers in the multilayer structure can be stacked directly or separated by a transparent medium (such as optical varnish or glass) to reduce interference between the layers. This is not a limitation of the present invention.

[0044] In one embodiment of the present invention, the optical system 100 further includes a light homogenization component 6, which is disposed between the beam splitter 2 and the fluorescent wheel 4. The light homogenization component 6 includes a third lens 61, a fourth lens 62, and a diffuser 63 arranged along a first direction. The diffuser 63 is used to evenly distribute the blue laser light emitted by the first light-emitting component 1. The third lens 61 is disposed adjacent to the first light-emitting component 1, and its side facing the first light-emitting component 1 is convex. When the first light-emitting component 1 emits blue laser light, the third lens 61 converges the blue laser light onto the fourth lens 62. The fourth lens 62 and the diffuser 63 then homogenize the blue laser light to facilitate subsequent optical path utilization.

[0045] By setting the side of the third lens 61 facing the first light-emitting component 1 to be convex, the blue laser emitted by the first light-emitting component 1 is converged to the third lens 62, and the laser is evenly distributed along the first direction through the planar third lens 62 and the diffuser 63; in another embodiment of the present invention, the diffuser 63 can also be set on the side of the beam splitter 2 facing the first light-emitting component 1, thereby reducing the structure of the optical system 100 and making the volume of the optical system 100 smaller.

[0046] It should be noted that in the related art, projection devices often produce a speckle effect when performing projection display. The speckle effect refers to the effect in which two laser beams emitted by a coherent light source interfere with each other in space after irradiating a rough object (such as the screen of a projection device) and scattering, and ultimately granular light and dark spots appear on the screen. The speckle effect makes the display effect of the projected image poor, and these unfocused light and dark spots appear to be flickering to the human eye, which can easily cause dizziness after long-term viewing, resulting in a poor viewing experience for users. In one embodiment of the present invention, the blue laser light emitted by the first light-emitting component 1 can be made more uniform by the action of the diffuser 63, and the interference generated by these lasers when used for projection is weaker, which can reduce the speckle effect when the projection device performs projection display, avoid the projected image from becoming blurred, improve the display effect of the projected image, and avoid the dizziness caused by viewing.

[0047] To better dissipate heat from the fluorescent wheel, in one embodiment of the present invention, the optical system 100 further includes a fan 7 , which is disposed on the side of the fluorescent wheel 4 facing away from the collimating lens assembly 3 and corresponding to the groove 42 . Since the fluorescent powder generates a large amount of heat during excitation, the provision of the fan 7 increases the air velocity in the vicinity, thereby cooling the groove 42 and preventing the entire optical system 100 from overheating and potentially damaging the system. In another embodiment of the present invention, a heat sink may be provided on the side of the fluorescent wheel 4 facing away from the collimating lens assembly 3 to increase heat dissipation from the aluminum substrate 41 . The heat sink may be disposed throughout the entire aluminum substrate 41 , or, to reduce material usage, may be provided corresponding to the position of the groove 42 to save costs.

[0048] In one embodiment of the present invention, the optical system 100 further includes a converging lens 8 and a light-smoothing component 9. The converging lens 8 is located on the side of the beam splitter 2 facing away from the second light-emitting component 5, and the side of the converging lens 8 facing the beam splitter 2 is configured as a convex surface. When the parallel yellow light is reflected in the second direction by the reflective portion of the beam splitter 2 and converges with the blue laser light emitted by the second light-emitting component 5, the converging lens 8 converges the three primary colors of light (white light) onto the light-smoothing component 9. The light-smoothing component 9 further homogenizes the white light, thereby improving the quality of the light source. In addition, the side of the converging lens 8 facing the beam splitter 2 is configured as a convex surface to enhance the converging effect on the light emitted by the beam splitter 2, allowing as much white light as possible to enter the light-smoothing component 9.

[0049] Please refer to Figure 1 In the embodiment of the present invention, the light transmission of the device is as follows:

[0050] The first light-emitting component 1 emits a blue laser along a first direction, and the third lens 61 converges the blue laser to the fourth lens 62. The fourth lens 62 and the diffuser 63 perform homogenization on the blue laser in turn. The blue laser passes through the beam splitter 2 that transmits blue light and reflects red and green light and enters the first lens 31. The first lens 31 focuses the laser onto the multilayer phosphor on the inner wall of the groove 42 of the aluminum substrate 41. The phosphor is excited to emit yellow light formed by a mixture of red and green light. The second lens 32 is arranged close to the groove 42 to ensure that as much excited light beam as possible is collected. The second lens 32 and the first lens 31 sequentially re-collimate the yellow light into parallel light. The parallel The yellow light is reflected to the second direction by the reflecting part of the spectrometer 2, and is converged with the blue laser emitted by the second light-emitting component 5 through the converging lens 8 and homogenized by the light-forming component 9 to form white light. Through such an arrangement, the light source uniformity of the optical system 100 is good and the optical efficiency is high. In addition, by forming a groove 42 in the area where the traditional flat aluminum substrate 41 is coated with phosphor, the inner wall coating of the groove 42 has a larger excitation surface area than the conventional flat coating, so that more light can be output and the brightness is improved, and the excitation surface is made into a curved surface, so that the divergence angle of the excited phosphor is smaller than the plane Lambertian divergence angle. The reduction of this angle will increase the light path light collection efficiency, facilitate the subsequent light collection design, and thus improve the optical efficiency.

[0051] The present invention also provides a projection device, which includes an optical system 100. The specific structure of the optical system 100 refers to the above embodiment. Since the present projection device adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, which will not be described one by one here.

[0052] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. An optical system, characterized in that: The optical system comprises a first light-emitting component, a beam splitter, a collimating lens group, a fluorescent wheel, and a second light-emitting component located on one side of the beam splitter along a second direction. The beam splitter is arranged in an inclined manner, and a reflective portion is provided on the side thereof facing the fluorescent wheel; The fluorescent wheel includes an aluminum substrate configured to rotate around a rotation axis. The rotation axis of the aluminum substrate is parallel to the first direction. A groove is formed on a side of the aluminum substrate facing the collimating lens assembly. The inner wall of the groove is coated with fluorescent powder.

2. The optical system according to claim 1, wherein The collimating lens assembly includes a first lens and a second lens arranged along a first direction; Wherein, the surface of the first lens facing the beam splitter is a convex surface, and the second lens is arranged close to the groove of the fluorescent wheel.

3. The optical system according to claim 1, wherein The groove is configured as an annular groove, and the center of the annular groove coincides with the rotation axis of the aluminum substrate.

4. The optical system according to claim 3, wherein The outer ring radius of the annular groove is R, the inner ring radius is r, and the distance between the optical axis of the collimating lens group and the rotation axis of the aluminum substrate is H, where R=H.

5. The optical system according to claim 1 or 3, wherein: The inner wall surface of the groove is configured as a curved surface.

6. The optical system according to claim 1 or 3, wherein: The inner wall surface of the groove is coated with multiple layers of phosphor.

7. The optical system according to claim 1, wherein The optical system further includes a light homogenization component, which is arranged between the beam splitter and the fluorescent wheel, and includes a third lens, a fourth lens and a diffuser arranged along a first direction; The third lens is disposed close to the first light-emitting component, and a side surface thereof facing the first light-emitting component is a convex surface.

8. The optical system according to claim 1, wherein: The optical system further includes a fan, which is arranged on a side of the fluorescent wheel facing away from the collimating lens assembly and corresponding to the groove.

9. The optical system according to claim 1, wherein: The optical system further comprises: a converging lens, the converging lens being located on a side of the beam splitter facing away from the second light-emitting component, and the converging lens being configured as a convex surface facing the beam splitter; and A light-rectifying component is arranged along the second direction corresponding to the convex surface of the converging lens.

10. A projection device, characterized in that: Comprising the optical system according to any one of claims 1 to 9.

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