Image Projection Device

Abstract

To provide an image projection device comprising two light sources and two phosphors, capable of downsizing a light source module synthesizing fluorescent light obtained from the two phosphors to output the same.SOLUTION: An image projection device comprises: a light source; two phosphor wheels 102-1, 102-2; a uniformizing element 103; an optical system guiding excitation light from the light source to the two phosphor wheels and guiding synthetic light obtained by synthesizing fluorescent light from the two phosphor wheels to the uniformizing element; an optical casing 110 tightly sealing the optical system; a first cooling casing 109-1 tightly sealing one of the two phosphor wheels and including a circulation path for air flow; and a second cooling casing 109-2 tightly sealing the other of the two phosphor wheels and including a circulation path for air flow. An axis of the circulation path of each of the first cooling casing and the second cooling casing perpendicularly intersects or is parallel to an optical axis of the synthetic light.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an image projection device. [Background technology]

[0002] In image projection devices such as projectors that use LDs (an example of a light source), the light source module generally comprises one LD and one phosphor. However, in order to increase the light output of the projector, a technology has been developed that comprises two LDs and two phosphors and combines and outputs the fluorescence obtained from the two phosphors (see Patent Document 1).

[0003] Furthermore, the light source module converts excitation light into fluorescence, and since the lower the temperature of the phosphor, the higher the conversion efficiency from excitation light to fluorescence tends to be, the phosphor is cooled to lower its temperature in order to increase the conversion efficiency from excitation light to fluorescence. Summary of the Invention [Problem to be solved by the invention]

[0004] However, in a projector equipped with two phosphors, if an attempt is made to cool both phosphors, the configuration of the projector becomes complicated, and there is a problem that the image projection device such as the projector becomes large.

[0005] The present invention has been made in consideration of the above, and aims to provide an image projection device that can miniaturize a light source module that has two light sources and two phosphors and combines and outputs the fluorescence obtained from the two phosphors. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the present invention provides a light source module including: 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 obtained by synthesizing fluorescence from the two phosphor wheels to the homogenizing element; an optical casing that seals the optical system; a first cooling casing that seals one of the two phosphor wheels and has an airflow circulation path; and a second cooling casing that seals the other of the two phosphor wheels and has an airflow circulation path; a light modulation element that modulates the light emitted from the homogenizing element; and a projection optical system that projects the light modulated by the light modulation element onto a display unit, wherein axes of the circulation paths of the first cooling casing and the second cooling casing are perpendicular to or parallel to an optical axis of the synthesized light. A heat absorbing member that is thermally connected to the inside and outside of the phosphor wheel, the first cooling casing, and the second cooling casing is disposed in the circulation path. do. [Effects of the Invention]

[0007] According to the present invention, it is possible to reduce the size of a light source module that includes two light sources and two phosphors and combines and outputs the fluorescence obtained from the two phosphors. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a projector to which an image projection device according to this embodiment is applied. [Figure 2] FIG. 2 is a diagram showing an example of a schematic configuration of a light source module according to the present embodiment. [Figure 3] FIG. 3 is a diagram showing another example of the outline of the light source module according to the present embodiment. [Figure 4] FIG. 4 is a diagram for explaining an example of the configuration of the heat receiving means and the heat dissipating means of the light source module according to the present embodiment. [Figure 5] FIG. 5 is a diagram for explaining another example of the configuration of the heat receiving means and the heat dissipating means of the light source module according to the present embodiment. [Figure 6]FIG. 6 is a view of the light source module according to this embodiment as viewed from the direction in which the combined light is emitted. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an image projection device will be described in detail below with reference to the accompanying drawings.

[0010] 1 is a diagram showing an example of the configuration of a projector to which an image projection device according to this embodiment is applied. As shown in FIG. 1, the projector according to this embodiment includes a light source module 1, a light modulation element 2, and a projection optical system 3.

[0011] The light source module 1 includes an LD (laser diode light source) which is an example of a light source, two phosphor wheels, a homogenizing element, and an optical system which guides excitation light from the LD to the two phosphor wheels and guides combined light obtained by combining fluorescence from the two phosphor wheels to the homogenizing element. The light modulation element 2 is an example of a light modulation element which modulates 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 which projects the light modulated by the light modulation element 2 onto a display unit such as a screen.

[0012] FIG. 2 is a diagram illustrating an example of a schematic configuration of a light source module according to the present embodiment. As illustrated in FIG. 2, the light source module 1 according to the present 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 heat receiving unit 107, a heat dissipation unit 108, a first cooling casing 109-1, a second cooling casing 109-2, and an optical casing 110. In the following description, when the phosphor wheels 102-1 and 102-2 are not distinguished, they are referred to as phosphor wheels 102. In the following description, when the first and second cooling casings 109-1 and 109-2 are not distinguished, they are referred to as cooling casings 109.

[0013] LD 101 is an example of an LD that emits light. In this embodiment, light source module 1 has two LDs 101. Dichroic mirror 104 reflects the light emitted from LD 101 and makes the light incident on the phosphor layer on phosphor wheel 102 as excitation light.

[0014] Phosphor wheel 102 is an example of a phosphor wheel that emits light (fluorescence) obtained by wavelength-converting light emitted from LD 101 and reflected by dichroic mirror 104. Prism 105 is an example of an optical system that guides to homogenizing element 103 synthesized light obtained by combining the fluorescence wavelength-converted by two phosphor wheels 102-1 and 102-2.

[0015] Optical casing 110 is an example of an optical casing that seals the optical system, such as dichroic mirror 104 and prism 105. First cooling casing 109-1 is an example of a first cooling casing that seals one of phosphor wheels 102-1 and 102-2 (phosphor wheel 102-1) and has an airflow circulation path therein. Second cooling casing 109-2 is an example of a second cooling casing that seals the other of phosphor wheels 102-1 and 102-2 (phosphor wheel 102-2) and has an airflow circulation path therein. That is, phosphor wheels 102-1 and 102-2 are each sealed by cooling casing 109 separately from the optical system, such as dichroic mirror 104 and prism 105.

[0016] Motor 106 rotates phosphor wheel 102. Heat receiving means 107 receives heat generated by phosphor wheel 102. Heat dissipation means 108 dissipates the heat received by heat receiving means 107 from phosphor wheel 102 to the outside of cooling casing 109. That is, in this embodiment, heat receiving means 107 and heat dissipation means 108 are examples of heat absorbing members that are thermally connected to the inside and outside of cooling casing 109. This allows heat generated by phosphor wheel 102 to be efficiently transferred to heat receiving means 107.

[0017] Heat receiving means 107 and phosphor wheel 102 are housed in cooling casing 109. A circulating air current is generated within cooling casing 109, and this circulating air current efficiently transfers heat generated by phosphor wheel 102 to heat receiving means 107. That is, phosphor wheel 102 and heat receiving means 107 (heat absorbing member) are arranged in the circulation path within cooling casing 109. Motor 106 may also be arranged in the circulation path within cooling casing 109. This allows motor 106 to be cooled in addition to phosphor wheel 102.

[0018] Here, the axis of the circulating airflow inside cooling casing 109 intersects perpendicularly with the rotation axis of motor 106. Furthermore, the optical axis of the combined light combined by prism 105 and the axis of the circulating airflow intersect perpendicularly. This makes the wall surfaces of optical casing 110 and cooling casing 109 parallel to each other, eliminating dead space and allowing light source module 1 to be made smaller.

[0019] That is, designing the light source module 1 based on the combined light makes it easier to design the entire light source module 1, and therefore, a compact design is possible if the optical casing 110 housing the optical system is shaped like a rectangular parallelepiped with faces parallel or perpendicular to the combined light. Furthermore, to ensure a uniform circulating airflow, a compact design is possible if the cooling casing 109 generating the circulating airflow is shaped like a rectangular parallelepiped with faces parallel or perpendicular to the axis of the circulating airflow. Therefore, in the light source module 1, the axis of the circulation path of the circulating airflow intersects or is parallel to the optical axis of the combined light, so that the wall surfaces of the optical casing 110 and the cooling casing 109 are parallel to each other, eliminating dead space and allowing the light source module 1 to be made smaller.

[0020] In this embodiment, the axis of the circulating airflow and the optical axis of the combined light are orthogonal (intersect perpendicularly), but for example, when the axis of the circulating airflow is tilted 90° in the direction of rotation of motor 106, the axis of the circulating airflow and the optical axis of the combined light become parallel. Even in this case, the wall surfaces of optical casing 110 and cooling casing 109 are parallel to each other, and no dead space is created, allowing light source module 1 to be made smaller.

[0021] Fig. 3 is a diagram showing another example of a schematic light source module according to the present embodiment. In the light source module 1 shown in Fig. 2, a motor 106 is attached to one of the two surfaces of the phosphor wheel 102 opposite to the surface onto which excitation light is incident. On the other hand, in the light source module 1 shown in Fig. 3, a motor 106 is attached to one of the two surfaces of the phosphor wheel 102 opposite to the surface onto which excitation light is incident.

[0022] 3 is arranged with the motor 106 facing in the opposite direction relative to the phosphor wheel 102, as compared to the light source module 1 shown in Fig. 2. This allows the circulating airflow within the cooling casing 109 to cool not only the phosphor wheel 102 but also the motor 106.

[0023] FIG. 4 is a diagram illustrating an example of the configuration of the heat receiving means and heat dissipating means of the light source module according to this embodiment. In this embodiment, as shown in FIG. 4, the heat receiving means 107 and the heat dissipating means 108 are aluminum heat sinks or the like, and their respective base members are in close contact with each other. That is, the heat absorbing member including the heat receiving means 107 and the heat dissipating means 108 may be made of a thermally conductive member (a member with good thermal conductivity) and may be made by bonding together two plate members (base members) having fins on one side. This makes it possible to transfer and dissipate heat from within the sealed cooling casing 109 to the outside of the cooling casing 109 with a low-cost configuration.

[0024] In this embodiment, the same heat sink is used for heat receiving means 107 and heat dissipation means 108, but this is not limited to this, and the size of the base member, the shape of the fins, the number of fins, etc. can be changed as appropriate. In addition, arranging a material with high thermal conductivity, such as a thermally conductive sheet or thermally conductive grease, at the contact point between the base member of heat receiving means 107 and the base member of heat dissipation means 108 is effective in dissipating heat from phosphor wheel 102.

[0025] FIG. 5 is a diagram illustrating another example of the configuration of the heat receiving means and heat dissipating means of the light source module according to this embodiment. In this embodiment, the heat receiving means 107 and the heat dissipating means 108 may be configured by fins standing on both sides of an aluminum base member. That is, the heat receiving means 107 and the heat dissipating means 108 may be a plate member (base member) having a thermally conductive member (a material with good thermal conductivity) and fins on both sides. This makes it possible to transfer and dissipate heat from the sealed cooling casing 109 to the outside of the cooling casing 109 with high efficiency. In this embodiment, the fins on both sides of the base member have the same shape and the same number, but this is not limited thereto, and the shape and number of the fins can be changed as appropriate.

[0026] 6 is a view of the light source module according to this embodiment as viewed from the emission direction of the combined light. In this embodiment, the fins of the heat dissipation means 108 (heat receiving means 107) in the cooling casing 109 are parallel to the emission direction of the combined light combined by the prism 105. As a result, the fins of the heat dissipation means 108 are aligned parallel to the combined light, so that ducts and fans for applying circulating airflow to the fins of the heat dissipation means 108 can be efficiently arranged, thereby making it possible to miniaturize various devices incorporating the light source module 1. In this embodiment, the fins of the heat dissipation means 108 are parallel to the combined light, but the same effect can be obtained even if the fins of the heat dissipation means 108 are aligned so as to intersect perpendicularly with the combined light.

[0027] That is, in heat receiving means 107 and heat dissipating means 108, the fins arranged on the outside of cooling casing 109 are arranged so as to intersect perpendicularly with or be parallel to the optical axis of the combined light. This allows for efficient arrangement of ducts and fans for applying airflow to the fins arranged on the outside of cooling casing 109, making it possible to miniaturize various devices such as projectors incorporating light source module 1.

[0028] In this embodiment, the axis of the circulating airflow and the optical axis of the combined light are either perpendicular to or parallel to each other, but it is not necessary for all the axes of the circulating airflow and the optical axis of the combined light to be either strictly perpendicular to or parallel to each other. Since the flow rate is less affected by errors in the thickness of the beam of the combined light and the circulating airflow casing shape, a range of ±20% will be sufficient to provide a satisfactory effect.

[0029] In this way, in the projector according to this embodiment, the optical axis of the combined light combined by the prism 105 and the axis of the circulating airflow intersect perpendicularly, so that the wall surfaces of the optical casing 110 and the cooling casing 109 are parallel to each other, and no dead space is created, allowing the light source module 1 to be made smaller. [Explanation of symbols]

[0030] 1 Light Source Module 2. Light modulation element 3 Projection optical system 101LD 102 Phosphor Wheel 103 Uniformizing element 104 Dichroic Mirror 105 Prism 106 Motor 107 Heat receiving means 108 Heat dissipation means 109 Cooling casing 110 Optical Casing [Prior art documents] [Patent documents]

[0031] [License 1] Patent No. 6236891

Claims

1. a light source module including 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 obtained by combining fluorescence from the two phosphor wheels to the homogenizing element, an optical casing that seals the optical system, a first cooling casing that seals one of the two phosphor wheels and has an airflow circulation path, and a second cooling casing that seals the other of the two phosphor wheels and has an airflow circulation path; a light modulation element that modulates the light emitted from the uniformizing element; a projection optical system that projects the light modulated by the light modulation element onto a display unit, an axis of the circulation path of each of the first cooling casing and the second cooling casing perpendicularly intersects with or is parallel to an optical axis of the combined light; an image projection device, wherein a heat absorbing member thermally connected to the inside and outside of the phosphor wheel, the first cooling casing, and the second cooling casing is disposed in the circulation path;

2. The image projection device according to claim 1 , wherein a motor for rotating the phosphor wheel is disposed in the circulation path.

3. 3. The image projection device according to claim 1, wherein the heat absorbing member is formed by bonding two plate members having a heat conductive member and fins on one side.

4. 3. The image projection device according to claim 1, wherein the heat absorbing member is a plate member having a heat conducting member and fins on both sides.

5. 5. The image projection device according to claim 3, wherein the fins of the heat absorbing member arranged on the outside of the first cooling casing and the second cooling casing are perpendicular to or parallel to the optical axis of the combined light.

6. 6. The image projection device according to claim 1, wherein the light source is an LD.

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