Image projection device
By employing two phosphor wheels and independent cooling housings in the image projection device, and utilizing circulating airflow to cool the phosphor wheels and configuring them crosswise or parallel to the optical system, the problem of large-scale light source modules is solved, achieving miniaturization and structural simplification.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- RICOH CO LTD
- Filing Date
- 2022-12-09
- Publication Date
- 2026-05-19
AI Technical Summary
In existing image projection devices, the complex cooling of the light source module with two phosphors leads to the problem of large device size.
The design employs two phosphor wheels and an independent cooling housing. The phosphor wheels are cooled by circulating airflow and are configured crosswise or parallel to the optical system. Combined with homogenizing elements and projection optical system, the light source module is miniaturized.
The light source module that outputs fluorescence after synthesis from two phosphors has been miniaturized, simplifying the structure and reducing cooling complexity.
Smart Images
Figure CN116430660B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to an image projection device. Background Technology
[0002] In image projection devices such as projectors that employ LDs (an example of a light source), the light source module typically includes one LD and one phosphor. However, prior art, such as Patent Document 1 (JP Patent No. 6236891), proposes a solution with two LDs and two phosphors, which synthesizes the fluorescence obtained from the two phosphors and outputs it, with the aim of increasing the light output of the projector.
[0003] On the other hand, the light source module converts excitation light into fluorescence. There is a tendency that the lower the temperature of the phosphor, the higher the conversion efficiency from excitation light to fluorescence. Therefore, in order to improve the conversion efficiency from excitation light to fluorescence, it is necessary to cool the phosphor to reduce its temperature.
[0004] However, in projectors with two phosphors, cooling the two phosphors complicates the projector structure, thus leading to the problem of larger image projection devices such as projectors. Summary of the Invention
[0005] In view of the above background, the present invention provides an image projection device having two light sources and two phosphors, the purpose of which is to miniaturize the light source module output after the fluorescence obtained from the two phosphors is synthesized.
[0006] To address the aforementioned problems and achieve the objective, the present invention provides an image projection device comprising: a light source module including a light source, two phosphor wheels, a homogenizing element, an optical system for guiding excitation light from the light source to the two phosphor wheels and guiding composite light synthesized from the phosphors emitted from the two phosphor wheels to the homogenizing element, an optical housing sealing the optical system, a first cooling housing sealing one of the two phosphor wheels and having a circulation path for airflow, and a second cooling housing sealing the other of the two phosphor wheels and having a circulation path for airflow; a light modulation element for modulating light emitted from the homogenizing element; and a projection optical system for projecting light modulated by the light modulation element onto a display unit, wherein the axes of the circulation paths in the first cooling housing and the second cooling housing are perpendicular to or parallel to the optical axis of the composite light.
[0007] The purpose of this invention is to provide an image projection device that has two light sources and two phosphors, enabling the miniaturization of the light source module after the fluorescence obtained from the two phosphors is synthesized and output. Attached Figure Description
[0008] Figure 1This is a schematic diagram of the configuration of a projector using the image projection device according to this embodiment.
[0009] Figure 2 This is a schematic diagram of a light source module involved in this embodiment.
[0010] Figure 3 This is a schematic diagram of another example of the light source module involved in this embodiment.
[0011] Figure 4 This is a schematic diagram of the heating and cooling mechanisms of the light source module involved in this embodiment.
[0012] Figure 5 This is a schematic diagram of the heating and cooling mechanisms of the light source module in another embodiment of this invention.
[0013] Figure 6 This is a schematic diagram of the light source module of this embodiment as viewed from the direction of the synthesized light emission. Detailed Implementation
[0014] The following describes in detail, with reference to the accompanying drawings, embodiments of the image projection device.
[0015] Figure 1 This is a schematic diagram illustrating the configuration of a projector employing the image projection apparatus described in this embodiment. Figure 1 As shown, the projector 1000 according to this embodiment has a light source module 1, a light modulation element 2, and a projection optical system 3.
[0016] The light source module 1 includes an LD (laser diode light source) as a light source, two phosphor wheels, a homogenizing element, and an optical system. The optical system guides the excitation light from the LD to the two phosphor wheels and guides the combined light from the combined fluorescence emitted by the two phosphor wheels to the homogenizing element. The light modulation element 2 is an example of a light modulation element that modulates the light emitted from the homogenizing element of the light source module 1. The projection optical system 3 is an example of a projection optical system that projects the light modulated by the light modulation element 2 onto a display unit such as a screen.
[0017] Figure 2 This is a schematic diagram of a light source module involved in this embodiment. Figure 2As shown, the light source module 1 involved in this embodiment includes two LDs 101, two phosphor wheels 102-1 and 102-2, a homogenizing element 103, a dichroic mirror 104, a prism 105, a motor 106, a heating device 107, a heat dissipation device 108, a first cooling housing 109-1, a second cooling housing 109-2, and an optical housing 110. In the following description, phosphor wheels 102-1 and 102-2 are referred to as phosphor wheel 102 without distinction. The first cooling housing 109-1 and the second cooling housing 109-2 are referred to as cooling housing 109 without distinction.
[0018] LD101 is an example of an LD that emits light. In this embodiment, the light source module 1 has two LD101s. The dichroic mirror 104 reflects the light emitted from the LD101 and incident it as excitation light onto the phosphor layer on the phosphor wheel 102.
[0019] The fluorescent wheel 102 is an example of a fluorescent wheel used to emit light, i.e., fluorescence, emitted from the LD 101 and reflected and wavelength-converted by the dichroic mirror 104. The prism 105 is an example of an optical system that guides the synthesized light, after wavelength conversion of the fluorescence from the two fluorescent wheels 102-1 and 102-2, into the homogenizing element 103.
[0020] The optical housing 110 is an example of an optical housing used to seal an optical system including a dichroic mirror 104, a prism 105, etc. The first cooling housing 109-1 is an example of a first cooling housing that seals one of the phosphor wheels 102-1 and 102-2 (in this case, phosphor wheel 102-1) and has an internal airflow circulation path. The second cooling housing 109-2 is an example of a second cooling housing that seals the other of the phosphor wheels 102-1 and 102-2 (in this case, phosphor wheel 102-2) and has an internal airflow circulation path. That is, the phosphor wheels 102-1 and 102-2 are sealed separately from the optical system including the dichroic mirror 104, the prism 105, etc., via the cooling housing 109.
[0021] Motor 106 drives fluorescent wheel 102 to rotate. Heating device 107 receives heat generated by fluorescent wheel 102. Heat dissipation device 108 dissipates the heat received from fluorescent wheel 102 through heating device 107 to the outside of cooling housing 109. That is, heating device 107 and heat dissipation device 108 in this embodiment are heat-absorbing components that connect the inside and outside of cooling housing 109. Therefore, the heat generated by fluorescent wheel 102 can be efficiently transferred to heating device 107.
[0022] The heating device 107 and the fluorescent wheel 102 are housed inside the cooling housing 109. A circulating airflow is generated inside the cooling housing 109, through which the heat generated by the fluorescent wheel 102 can be effectively transferred to the heating device 107. In other words, the fluorescent wheel 102 and the heating device 107 (heat-absorbing component) are arranged in the circulation path of the cooling housing 109. The motor 106 can be disposed in the circulation path inside the cooling housing 109. Thus, in addition to cooling the fluorescent wheel 102, the motor 106 can also be cooled.
[0023] Here, the axis of the circulating airflow within the cooling housing 109 intersects perpendicularly with the rotation axis of the motor 106. The optical axis of the synthesized light synthesized by the prism 105 intersects perpendicularly with the axis of the circulating airflow. In this way, the walls of the optical housing 110 and the cooling housing 109 are parallel to each other, eliminating dead angles and thus enabling the reduction in the size of the light source module 1.
[0024] In other words, by designing the light source module 1 based on the synthesized light, the overall design of the light source module 1 becomes easier. The shape of the optical housing 110, which houses the optical system, is a cuboid with faces parallel or perpendicular to the synthesized light, thus achieving a compact design. Furthermore, to ensure uniform airflow, the cooling housing 109, which generates the airflow, is formed as a cuboid with faces parallel or perpendicular to the axis of the airflow, further achieving a compact design. Therefore, the axis of the circulation path of the airflow in the light source module 1 intersects perpendicularly or parallel to the optical axis of the synthesized light, so that the walls of the optical housing 110 and the cooling housing 109 are parallel to each other, eliminating dead angles and enabling a smaller light source module 1.
[0025] In this embodiment, the axis of the circulating airflow is orthogonal (perpendicularly intersecting) to the optical axis of the synthesized light. For example, when the axis of the circulating airflow is tilted 90° toward the rotation direction of the motor 106, the axis of the circulating airflow and the optical axis of the synthesized light become parallel. In this case, the walls of the optical housing 110 and the cooling housing 109 are parallel to each other, and no dead angle is generated, thus the light source module 1 can be reduced in size.
[0026] Figure 3 This is a schematic diagram of another example of the light source module involved in this embodiment. Figure 2 In the light source module 1 shown, the motor 106 is mounted on the side of the phosphor wheel 102 opposite to the side where the excitation light is incident. Regarding this, Figure 3 In the light source module 1 shown, the motor 106 is mounted on the surface of the excitation light incident on one of the two surfaces of the fluorescent wheel 102.
[0027] In other words, Figure 3 The light source module 1 shown is relative to Figure 2The light source module 1 shown has the fluorescent wheel 102 as a reference, and the motors 106 are oriented opposite to each other. In this way, through the action of the circulating airflow in the cooling housing 109, not only the fluorescent wheel 102 but also the motors 106 can be cooled.
[0028] Figure 4 This is a schematic diagram of an example of the heating and cooling devices for the light source module involved in this embodiment. Figure 4 As shown, in this embodiment, the heating device 107 and the heat dissipation device 108 are made of aluminum heat sinks or the like, with each base component in close contact. That is, the heat-absorbing component, including the heating device 107 and the heat dissipation device 108, can be a component consisting of two plate components (base components) with thermally conductive components (good thermally conductive components) and blades on one side, tightly bonded together. In this way, heat can be transferred from the sealed cooling housing 109 to the outside of the cooling housing 109 with a low-cost structure.
[0029] In this embodiment, the heating device 107 and the heat dissipation device 108 use the same heat sink, but are not limited to this. The size of the base component, the shape of the blades, the number of blades, etc., can be appropriately changed. By providing components with high thermal conductivity, such as heat-conducting sheets and thermally conductive grease, at the contact points between the base components of the heating device 107 and the base components of the heat dissipation device 108, heat dissipation of the fluorescent wheel 102 can be effectively achieved.
[0030] Figure 5 This is another example of a structural schematic diagram of the heating and cooling devices included in the light source module according to this embodiment. In this embodiment, the heating device 107 and the cooling device 108 can be structures in which blades are erected on both sides of the aluminum substrate component. That is, the heating device 107 and the cooling device 108 can also be plate components (substrate components) with thermally conductive components (good thermally conductive components) and blades on both sides. In this way, the heat inside the sealed cooling housing 109 can be efficiently transferred to the outside of the cooling housing 109 for heat dissipation. In this embodiment, the blades on both sides of the substrate component have the same shape and the same number of blades, but it is not limited to this, and the shape and number of blades can be appropriately changed.
[0031] Figure 6 This is a diagram showing the light source module according to this embodiment as viewed from the direction of the synthesized light emission. In this embodiment, the blades of the heat dissipation device 108 (heat receiving device 107) inside the cooling housing 109 are parallel to the emission direction of the synthesized light synthesized by the prism 105. Because the blades of the heat dissipation device 108 are aligned parallel to the synthesized light, ducts and fans that allow circulating airflow to act on the blades of the heat dissipation device 108 can be efficiently configured, thereby miniaturizing various devices equipped with the light source module 1. Although the blades of the heat dissipation device 108 are parallel to the synthesized light in this embodiment, the same effect can be achieved even if the blades of the heat dissipation device 108 are perpendicular to the synthesized light.
[0032] In other words, the blades in the heating device 107 and the heat dissipation device 108 that are disposed outside the cooling housing 109 are perpendicular to or parallel to the optical axis of the synthesized light. This allows for efficient airflow to the ducts and fans disposed on the blades outside the cooling housing 109, enabling the miniaturization of various devices such as projectors that carry the light source module 1.
[0033] In this embodiment, the axis of the circulating airflow is perpendicular to or parallel to the optical axis of the synthesized light. However, it is not necessary for all the axes of the circulating airflow to be strictly perpendicular to or parallel to the optical axis of the synthesized light. Even if there are errors in the thickness of the synthesized light beam or the shape of the shell, the circulating airflow is not easily affected by the flow rate. Therefore, sufficient effect can be obtained as long as it is within ±20%.
[0034] As described above, in the projector of this embodiment, the optical axis of the synthesized light synthesized by the prism 105 intersects perpendicularly with the axis of the circulating airflow, and the walls of the optical housing 110 and the cooling housing 109 are parallel to each other, so no dead angle is generated, and the light source module 1 can be reduced in size.
[0035] Explanation of reference numerals in the attached figures
[0036] 1. Light source module
[0037] 2. Optical modulation element
[0038] 3. Projection Optical System
[0039] 101LD
[0040] 102 Glowing Wheel
[0041] 103 Homogenizing element
[0042] 104 Dichroic Mirror
[0043] 105 prism
[0044] 106 motor
[0045] 107 Heating Device
[0046] 108 Heat dissipation device
[0047] 109 Cooling Housing
[0048] 110 Optical housing
Claims
1. An image projection device, comprising: A light source module includes a light source, two phosphor wheels, a homogenizing element, an optical system that guides excitation light from the light source to the two phosphor wheels and guides synthesized light from the phosphors emitted from the two phosphor wheels to the homogenizing element, an optical housing that seals the optical system, a first cooling housing that seals one of the two phosphor wheels and has a circulation path for airflow, and a second cooling housing that seals the other of the two phosphor wheels and has a circulation path for airflow. An optical modulation element is used to modulate the light emitted from the homogenizing element; as well as A projection optical system is used to project light modulated by the light modulation element onto the display unit. The axes of the circulation paths in the first and second cooling housings are perpendicular to or parallel to the optical axis of the synthesized light, thereby making the walls of the optical housing and the first and second cooling housings parallel to each other.
2. The image projection device according to claim 1, wherein, A heat-absorbing component is provided on the circulation path to thermally connect the inner and outer surfaces of the fluorescent wheel, the first cooling housing, and the second cooling housing.
3. The image projection device according to claim 2, wherein, A motor is provided on the loop path to drive the rotation of the fluorescent wheel.
4. The image projection device according to claim 2 or 3, wherein, The heat-absorbing component is formed by bonding two plate components, each with a heat-conducting component and blades on one side of its surface.
5. The image projection apparatus according to claim 2 or 3, wherein, The heat-absorbing component is a plate component with heat-conducting components and blades on both sides.
6. The image projection device according to claim 4, wherein, In the heat-absorbing component, the blades located on the outside of the first cooling housing and the second cooling housing are perpendicular to or parallel to the optical axis of the synthesized light.
7. The image projection apparatus according to any one of claims 1 to 3, wherein, The light source is an LD (Light Detector).