Projection-type image display device

Abstract

The present invention provides a projection-type image display device that cools heat-generating components in a sealed state. [Solution] The projection-type image display device 1 according to the present disclosure is a projection-type image display device comprising a light source and an image display element into which light from the light source is incident, comprising: a first housing that houses the light source and the image display element and forms a sealed first space X1; a second housing that encloses the first housing and forms a second space X2 with the first housing, and has an outside air intake port 113 and an outside air exhaust port 111; a first heat exchanger 104 disposed in the second space that transfers the heat of the image display element to the outside air in the second space; a second heat exchanger 117 disposed in the second space that transfers the heat of the light source to the outside air in the second space; and a first blower disposed in the second space that takes in outside air into the second space through the intake port and discharges outside air from the second space through the exhaust port.

Description

Technical Field

[0001] The present disclosure relates to a projection-type image display device.

Background Art

[0002] A projection-type image display device irradiates a powerful illumination light onto an image display element such as a liquid crystal, and enlarges and projects the image displayed on the image display element with a projection lens. At this time, since the image display element absorbs some light, the image display element generates heat. Also, since the projection light has a large energy, the light source also generates heat. Therefore, it is required to effectively remove heat from the image display element and the light source.

[0003] Generally, a projection-type image display device has a configuration in which outside air is taken in to cool the heat-generating components. However, when outside air is taken in, dust and dirt flow into the interior of the projection-type image display device together with the outside air. There are concerns that dust and dirt adhere to the optical system, deteriorate the image quality, or receive light and become a starting point for heat generation.

[0004] In order to suppress the inflow of dust and dirt, a dust-proof filter is provided at the outside air inlet. In such a configuration, maintenance such as regular replacement or cleaning of the dust-proof filter is required.

[0005] In view of such problems, for example, a projection-type image display device of Patent Document 1 has been proposed.

[0006] Patent Document 1 discloses a projection-type image display device including a plurality of blowers for cooling a liquid crystal panel mounted on an illumination optical system, a heat sink for removing heat from the air blown out from the blowers, and a dust-proof case. The dust-proof case houses the illumination optical system, the blowers, and the heat sink, and has a sealed structure.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

[0008] However, the sealed structure described in Patent Document 1 does not include a light source unit. Therefore, the projection-type image display device cannot be used in environments where it is exposed to water or where there is a concern about salt damage.

[0009] Therefore, the purpose of this disclosure is to solve the aforementioned problems by providing a projection-type image display device that cools heat-generating components in a sealed state. [Means for solving the problem]

[0010] A projection image display device according to one aspect of the present disclosure is a projection image display device comprising a light source and an image display element into which light from the light source is incident, comprising: a first housing that houses the light source and the image display element and forms a sealed first space; a second housing that encloses the first housing and forms a second space with the first housing, and has an air intake port for outside air and an air exhaust port for outside air; a first heat exchanger disposed in the second space that transfers heat from the image display element to the outside air in the second space; a second heat exchanger disposed in the second space that transfers heat from the light source to the outside air in the second space; and a first blower disposed in the second space that takes in outside air into the second space through the air intake port and discharges outside air from the second space through the exhaust port. [Effects of the Invention]

[0011] According to this disclosure, it is possible to provide a projection-type image display device that cools heat-generating components in a sealed state. [Brief explanation of the drawing]

[0012] [Figure 1] Plane conceptual diagram of the overall configuration of the projection-type image display device according to Embodiment 1 [Figure 2] Side view conceptual diagram of the overall configuration of a projection-type image display device. [Figure 3]Schematic diagram showing the air flow in a projection-type image display device [Figure 4] Schematic perspective view showing the layout configuration of a projection-type image display device [Figure 5A] Front cross-sectional view in Figure 4 [Figure 5B] Cross-sectional view with the cross-section position changed parallel to that in Figure 5A [Figure 6] Top cross-sectional view in Figure 4 [Figure 7A] Perspective view of the first heat exchanger [Figure 7B] Perspective view of the partition wall enclosed in the first heat exchanger [Figure 8] Diagram showing the optical configuration [Figure 9] Diagram showing the optical configuration of the projection-type image display device according to Embodiment 2 [Figure 10] Top cross-sectional view of the projection-type image display device according to Embodiment 2 [Figure 11] Cross-sectional view with the cross-section position changed vertically from Figure 10 [Figure 12] Intake part cross-sectional view of the projection-type image display device according to Embodiment 2 [Figure 13] Bottom cross-sectional view of the projection-type image display device according to Embodiment 2

MODE FOR CARRYING OUT THE INVENTION

[0013] Hereinafter, embodiments will be described in detail with appropriate reference to the drawings. However, detailed descriptions that are not necessary may be omitted. For example, detailed descriptions of well-known matters and redundant descriptions of substantially the same configurations may be omitted. This is to avoid making the following description unnecessarily redundant and to facilitate the understanding of those skilled in the art.

[0014] Note that the attached drawings and the following description are provided for those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims. Also, in each figure, for ease of explanation, each element is shown exaggerated.

[0015] (Embodiment 1) FIG. 1 is a plan conceptual diagram of the overall configuration of the projection type image display device 1 according to Embodiment 1. FIG. 2 is a side conceptual diagram of the overall configuration of the projection type image display device 1. Although the optical paths of RGB should originally be described, in FIG. 2, due to the relationship of the drawing, only two liquid crystal units 200 are mentioned, and the illustration of the configuration related to the circulation fan 503 is omitted.

[0016] As shown in FIG. 1, the projection type image display device 1 includes an optical configuration 100, a first housing 500, a second housing 101, a base 118, a first heat exchanger 104, a second heat exchanger 117, outside air fans 103, 114, circulation fans 501 to 503, a power supply 511, and a power supply fan 512.

[0017] The optical configuration 100 is composed of a plurality of optical systems, and includes a light source unit 300 and an illumination optical unit 400 including a liquid crystal unit 200. The optical configuration 100 guides the light from the light source unit 300 to the illumination optical unit 400, and enlarges and projects the image or video displayed on the liquid crystal unit 200 onto a screen (not shown) by a projection lens 421. In Embodiment 1, the light source unit 300 includes a laser light source 301, and the illumination optical unit 400 includes three liquid crystal units 200 as an example of an image display element. The liquid crystal unit 200 has a configuration in which a liquid crystal panel for displaying an image to be enlarged and projected is sandwiched between two polarizing plates. When the image is enlarged and projected, the laser light source 301 and the liquid crystal unit 200 generate heat. In order to remove the heat of the laser light source 301 and the liquid crystal unit 200, cooling of the laser light source 301 and the liquid crystal unit 200 is required.

[0018] The light source unit 300 is housed in a light source block 116, and the illumination optical unit 400 is housed in an illumination case 420. The light source block 116 may be formed of a heat insulating member.

[0019] The first housing 500 houses the laser light source 301 and the liquid crystal unit 200, forming a sealed first space X1. In the first space X1, the entry of outside air is restricted. In Embodiment 1, the sealed first space X1 is an airtight space in which the inflow and outflow of external gases are blocked. The first space X1 only needs to be sealed from the outside air and may be in communication with other sealed spaces.

[0020] In Embodiment 1, the first housing 500 houses the optical configuration 100, including the laser light source 301 and the liquid crystal unit 200, in the first space X1. By housing the optical configuration 100 in the first space X1, it is possible to suppress the adhesion of dust and water droplets contained in the outside air to the optical configuration 100 and the occurrence of salt damage. The air in the first space X1 and other sealed spaces communicating with the first space X1 is called internal air, and the air outside the first space X1 and other sealed spaces communicating with the first space X1 is called external air. Note that the internal air is not limited to air, but may be helium or argon.

[0021] Although not shown in Figure 1, the first housing 500 has a transparent glass plate on the side of the projection lens 421 that is facing outwards. This configuration ensures that the projection lens 421 is sealed within the first space X1.

[0022] The second housing 101 is a component that encloses the first housing 500. The second housing 101 forms a second space X2 between itself and the first housing 500. The second space X2 is divided into two spaces on one side and the other side of the first housing 500. The two spaces may be in communication with each other. Specifically, the second space X2 is divided into a space on one side of the first housing 500 that houses the first heat exchanger 104, and a space on the other side of the first housing 500 that houses the second heat exchanger 117.

[0023] Here, the fact that the first housing 500 is enclosed within the second housing 101 means that the first housing 500 is located inside the outer surface of the second housing 101. In other words, the first housing 500 and the second housing 101 mainly form a double housing. On the other hand, the first housing 500 may have a part that is common with the second housing 101 in some respects.

[0024] The second housing 101 has outside air intake ports 102, 113 and outside air exhaust ports 111, 115. In the second space X2, two paths are formed: one through which outside air flows into the second space X2 via the intake port 102 and out through the exhaust port 111, and another through which outside air flows into the second space X2 via the intake port 113 and out through the exhaust port 115.

[0025] By making the first housing 500 and the second housing 101 separate components, they can be formed from different materials. The first housing 500 may be made of a material with thermal insulation properties to suppress the internal air from being affected by external thermal influences. Furthermore, since the first housing 500 has a complex shape to compactly arrange and house multiple components, it may be made of a moldable material. On the other hand, the second housing 101 may be made of a material that has weather resistance against external loads such as rain, wind, and sunlight. In Embodiment 1, the first housing 500 is made of resin, for example, a resin molded product such as engineering plastic. The second housing 101 is made of metal such as aluminum.

[0026] The base 118 is a plate-shaped member that supports the first housing 500 and the second housing 101. In other words, the base 118 constitutes a common bottom for the first housing 500 and the second housing 101. The base 118 may also support the optical configuration 100.

[0027] The first heat exchanger 104 is located in the second space X2 and transfers heat from the liquid crystal unit 200 to the outside air in the second space X2. In other words, the first heat exchanger 104 performs unidirectional heat exchange to cool the liquid crystal unit 200. As shown in Figure 2, in Embodiment 1, the first heat exchanger 104 has a partition wall 106 that defines an internal air passage 107 on one side and an external air passage 105 on the other side. The external air passage 105 is in contact with the internal air passage 107 via the partition wall 106. The internal air passage 107 is a sealed passage that communicates with the first space X1. The internal air passage 107 allows the internal air in the first space X1 to pass through, and the external air passage 105 allows the external air in the second space X2 to pass through. The internal air passage 107 has an inlet 108 (Figure 1) and an outlet 112 (Figure 1) that communicate with the first space X1. The inlet 108 allows internal air to pass from the first space X1 into the internal air passage 107, and the outlet 112 allows internal air to pass from the internal air passage 107 towards the first space X1.

[0028] The internal air in the first space X1 is heated by absorbing heat from the liquid crystal unit 200. Through the passage of internal and external air in the first heat exchanger 104, heat from the liquid crystal unit 200 is transferred from the internal air to the external air via the partition wall 106. This configuration enables cooling of the liquid crystal unit 200 via the internal air.

[0029] Returning to Figure 1, the first heat exchanger 104 is positioned in the second space X2 between the intake port 102 and the exhaust port 111. The outside air flowing from the intake port 102 to the exhaust port 111 passes through the outside air passage 105 (Figure 2).

[0030] The second heat exchanger 117 is located in the second space X2 and transfers heat from the laser light source 301 to the outside air in the second space X2. In other words, the second heat exchanger 117 performs unidirectional heat exchange to cool the laser light source 301. In Embodiment 1, the second heat exchanger 117 is a heat sink connected to the laser light source 301. The second heat exchanger 117 penetrates the first housing 500 and is located in the second space X2 between the intake port 113 and the exhaust port 115. A seal is provided between the second heat exchanger 117 and the first housing 500 to suppress air leakage from the first space X1. Outside air moving from the intake port 113 to the exhaust port 115 passes through the second heat exchanger 117. In addition, the laser light source 301 is connected to the second heat exchanger 117 directly or indirectly, and heat from the laser light source 301 is transferred to it. In Embodiment 1, the second heat exchanger 117 is mechanically connected to the laser light source 301 via a thermally conductive material (such as grease) on the back of the laser light source 301. The heat transferred is dissipated towards the passing outside air. This configuration enables cooling of the laser light source 301.

[0031] The first heat exchanger 104 is positioned closer to the intake port 102 than to the intake port 113, and the second heat exchanger 117 is positioned closer to the intake port 113 than to the intake port 102. In the second housing 101, two intake ports 102 and 113 are provided to divide the flow of outside air, allowing the flow of outside air in the first heat exchanger 104 and the second heat exchanger 117 to be independent of each other. With this configuration, the heat dissipation of the laser light source 301 is avoided by the first heat exchanger 104, and the laser light source 301 can be cooled without affecting the first heat exchanger 104 and the internal air in the first space X1.

[0032] The outside air fan 103 is located in the second space X2 and takes in outside air into the second space X2 through the intake port 102 and discharges the outside air from the second space X2 through the exhaust port 111. The outside air fan 103 guides the outside air from the second space X2 to the outside air passage 105 of the first heat exchanger 104, passes it through the outside air passage 105, and discharges it through the exhaust port 111.

[0033] The outside air fan 114 is located in the second space X2 and is a blower that takes in outside air into the second space X2 through the intake port 113 and discharges it through the exhaust port 115. The outside air fan 114 guides the outside air to the second heat exchanger 117.

[0034] Since the outside fans 103 and 114 are directly exposed to the outside air, they may be weather-resistant fans, such as waterproof or oil-resistant fans, that are currently available on the market. For example, the outside fans 103 and 114 are waterproof or oil-resistant axial fans or sirocco fans.

[0035] Multiple circulation fans 501 to 503 are arranged in the first space X1 and are blowers that guide the internal air in the first space X1 to the internal air passage 107, pass through the internal air passage 107, and guide it to the liquid crystal unit 200. In Embodiment 1, the circulation fans 501 to 503 circulate the internal air between the liquid crystal unit 200 and the first heat exchanger 104. Specifically, the circulation fans 501 to 503 send the internal air, which has been heated by absorbing heat from the liquid crystal unit 200, to the first heat exchanger 104, and then send the internal air, which has been cooled in the first heat exchanger 104, back to the liquid crystal unit 200. With this configuration, the heat from the liquid crystal unit 200 is transported to the first heat exchanger 104 via the circulation of internal air. In Embodiment 1, three circulation fans 501 to 503 are provided, each corresponding to one of the three liquid crystal units 200.

[0036] As shown in Figure 2, the circulation fans 501 and 502 are positioned below the lighting case 420 that houses the liquid crystal unit 200. Furthermore, the optical systems 201 to 203 of the liquid crystal unit 200 are arranged so that their incident surfaces, which receive illumination light, extend vertically. With the liquid crystal unit 200 arranged in this manner, the circulation fans 501 and 502 draw in internal air from the side and blow it upwards from below the liquid crystal unit 200. This configuration allows for uniform cooling by bringing the internal air into contact with the incident surfaces of each optical system 201 to 203 of the liquid crystal unit 200.

[0037] In Embodiment 1, sirocco fans are used as circulation fans 501 to 503, which can obtain high static pressure in a limited space.

[0038] Returning to Figure 1, the power supply 511 is a component that supplies power to the light source unit 300 and the electrical circuit board 509. The electrical circuit board 509 is electrically connected to the power supply 511 and is a board on which an electronic circuit that controls the projection-type image display device 1 is mounted. The electronic circuit consists of a circuit pattern formed on the electrical circuit board 509 and electronic components electrically connected to the circuit pattern. The electrical circuit board 509 is located above the lighting case 420. The power supply 511 generates heat when power is supplied. To suppress malfunctions, cooling of the power supply 511 is required.

[0039] The power supply fan 512 is a blower positioned near the power supply 511 in the first space X1. The power supply fan 512 blows internal air toward the power supply 511. This configuration allows the power supply 511 to be cooled.

[0040] Next, we will explain in more detail the configuration related to the cooling of the liquid crystal unit 200 by the first heat exchanger 104.

[0041] To cool the liquid crystal unit 200, the first heat exchanger 104 transfers heat from the internal air to the external air by passing the internal air through it. First, the flow of internal and external air in the projection-type image display device 1 will be explained with reference to Figure 3. Figure 3 is a schematic diagram showing the airflow in the projection-type image display device.

[0042] As shown in Figure 3, when the outside air fan 103 rotates, outside air flows into the second housing 101 through the intake port 102 and passes through the outside air passage 105 (Figure 6) of the first heat exchanger 104. The outside air that flows out from the outside air passage 105 is discharged to the outside of the second housing 101 through the exhaust port 111.

[0043] Meanwhile, the internal air circulates between the internal air passage 107 of the first heat exchanger 104 and the first space X1. The internal air passage 107 is connected to the first space X1 of the first housing 500 to form a sealed space. The projection-type image display device 1 has a plurality of air ducts 515, 505a to 505c, a lighting case 420, an air duct case 510, and a power supply air duct 513 in the first space X1 to form an internal air circulation path.

[0044] When the circulation fans 501-503 rotate, the internal air is drawn into the circulation fans 501-503, flows out from the outlet 112 of the internal air passage 107, and enters the air guide duct 515. The internal air is drawn into each of the circulation fans 501-503 and flows in the direction of each of the circulation fans 501-503. The internal air drawn into the circulation fans 501-503 flows through the air guide ducts 505a-505c into the lighting case 420 where the LCD unit 200 is located. The internal air guided to the LCD unit 200 is discharged from the lighting case 420 and enters the air guide case 510.

[0045] When the power supply fan 512 rotates, the internal air is drawn into the power supply fan 512 and flows into the power supply air duct 513 from the case outlet 510a. The internal air passes through the power supply 511 and flows into the internal air passage 107 of the first heat exchanger 104 through the inlet 108. The internal air flowing through the internal air passage 107 returns to the outlet 112. With this structure, the internal air circulates within the first enclosure 500.

[0046] Next, the configuration related to the internal airflow will be explained in more detail with reference to Figures 4 to 6. Figure 4 is a schematic perspective view showing the arrangement of the projection-type image display device 1. In Figure 4, the first housing 500 and the second housing 101 are omitted. Figure 5A is a front cross-sectional view of Figure 4. Figure 5B is a perspective view from Figure 5A with a parallel cross-sectional position. Figure 6 is a top cross-sectional view of Figure 4.

[0047] As shown in Figures 4 and 5A, the air guide duct 515 is a member that extends between the outlet 112 of the internal air passage 107 of the first heat exchanger 104 and the circulation fans 501 to 503, and has a flow path inside. In Embodiment 1, one end of the air guide duct 515 is connected to the outlet 112 of the internal air passage of the first heat exchanger 104, and the other end of the air guide duct 515 is connected to the intake port of the circulation fans 501 to 503. Part of the air guide duct 515 is formed by hollowing out a part of the base 118, but is not limited to this.

[0048] The first flow path 504 is formed by the air guide duct 515.

[0049] As shown in Figures 5A and 5B, the air guide ducts 505a and 505b extend between the circulation fans 501 and 502 and the liquid crystal unit 200 and are components having a flow path inside. In Embodiment 1, one end of the air guide ducts 505a and 505b is connected to the discharge ports of the circulation fans 501 and 502, respectively, and the other end of the air guide ducts 505a and 505b is connected to the lighting case 420. The air guide ducts 505a and 505b are formed by hollowing out a part of the base 118, but are not limited to this.

[0050] The air ducts 505a and 505b form the second flow paths 506a and 506b, respectively.

[0051] Although not shown in the diagram, the air guide ducts 505a and 505b may have a nozzle shape at the connection point with the lighting case 420. This structure allows the internal air to be efficiently concentrated on the components of the liquid crystal unit 200.

[0052] As shown in Figure 5B, the lighting case 420 defines third channels 507a and 507b, which communicate with the second channels 506a and 506b, by its inner wall. The liquid crystal unit 200 is housed in the third channels 507a and 507b. The third channels 507a and 507b extend vertically along the incident surface of the liquid crystal unit 200.

[0053] Furthermore, due to the limitations of the drawings, the description of the circulation fan 503 is omitted, but like the other circulation fans 501 and 502, it is equipped with an air intake duct 505c, a second flow path 506c, and a third flow path 507c (see Figure 3).

[0054] As shown in Figures 4 and 5B, a ventilation case 510 is further provided on top of the lighting case 420. The inner wall of the ventilation case 510 forms a fourth flow path 508 with the upper surface of the lighting case 420. The ventilation case 510 forms a case outlet 510a at a position close to the power supply ventilation duct 513.

[0055] Returning to Figure 2, the air guide case 510 is positioned between the lighting case 420 and the electrical circuit board 509. By providing the air guide case 510, it is possible to suppress the internal air, which has been heated by absorbing heat from the liquid crystal unit 200, from coming into contact with the electrical circuit board 509.

[0056] As shown in Figure 6, the power supply air duct 513 is a component that extends between the liquid crystal unit 200 and the inlet 108 of the internal air passage 107 of the first heat exchanger 104 and has a flow path inside. The power supply 511 is housed in the power supply air duct 513. In Embodiment 1, one end of the power supply air duct 513 faces the power supply fan 512, and the other end of the power supply air duct 513 is connected to the inlet 108 of the internal air passage of the first heat exchanger 104. The power supply fan 512 causes air to flow into the power supply air duct 513.

[0057] The power supply air duct 513 forms the fifth flow path 514.

[0058] This configuration allows for more reliable airflow to the heat-generating liquid crystal unit 200 and power supply 511, and the heated air can then be sent to the first heat exchanger 104.

[0059] Next, the structure of the first heat exchanger 104 will be described in more detail with reference to Figures 7A and 7B. Figure 7A is a perspective view of the heat exchanger 104. Figure 7B is a perspective view of the partition wall 106 contained within the heat exchanger 104.

[0060] As shown in Figure 7A, the first heat exchanger 104 has a heat exchange case 122 and a partition wall 106 housed within the heat exchange case 122. In Embodiment 1, the heat exchange case 122 has a rectangular parallelepiped shape. The partition wall 106 extends along the longitudinal direction of the heat exchange case 122, dividing the internal space of the heat exchange case 122 into two independent flow paths extending along the longitudinal direction. As shown in Figure 7B, the partition wall 106 has a corrugated shape. Therefore, the area of ​​the partition wall 106 that comes into contact with the outside air and the inside air can be increased.

[0061] Returning to Figure 7A, both longitudinal ends of the heat exchanger 104 are open to the outside air on one side of the partition wall 106 and sealed by the comb-shaped plate 120 on the other side of the partition wall 106. With this structure, the outside air passage 105 is open to the outside air, and the inside air passage 107 is sealed to the outside air.

[0062] One end of the open heat exchanger 104 becomes the inlet 109 of the outside air passage 105, and the other end becomes the outlet 110 of the outside air passage 105. The inlet 109 of the outside air passage 105 communicates with the intake port 102 (Figure 1) of the second housing 101, and the outlet 110 of the outside air passage 105 communicates with the exhaust port 111 (Figure 1) of the second housing 101.

[0063] The inlet 108 and outlet 112 of the internal air passage 107 are formed on the side surface 122A connected to the first housing 500. Therefore, the direction of internal air inflow or outflow intersects with the direction in which the internal air passage 107 extends. In Embodiment 1, the direction of internal air inflow or outflow is perpendicular to the direction in which the internal air passage 107 extends. Also, the inlet 108 and outlet 112 are arranged on substantially the same plane. With this structure, the length of the internal air passage 107 can be secured while miniaturizing the projection-type image display device 1. Since the flow velocity in the internal air passage 107 is not high, even if the internal air passage 107 is curved, the internal air flows without hindrance due to the pressure difference generated by each of the circulation fans 501 to 503.

[0064] The first heat exchanger 104 is connected to the side of the first housing 500 at the side surface 122A of the heat exchange case 122. The first heat exchanger 104 is connected in such a way that it seals the first housing 500 so that there is no air leakage from the internal air passage 107.

[0065] As shown in Figure 1, the outlet 112 of the internal airflow channel 107 is positioned closer to the liquid crystal unit 200 than the inlet 108. In Embodiment 1, the first heat exchanger 104 is positioned along the side of the first housing 500 such that the outlet 112 is located near the center of the liquid crystal unit 200. This arrangement makes it possible to suppress the difference in distance between the outlet 112 and the respective circulation fans 501 to 503. Therefore, temperature unevenness in each cooling target (liquid crystal unit 200) can be suppressed.

[0066] Next, we will return to Figures 3, 5A, 5B, and 6 and explain the heat transfer in the first heat exchanger 104.

[0067] As shown in Figure 5A, when the circulation fans 501 to 503 rotate, the internal air flows out from the outlet 112 of the internal air passage 107 and flows into the first passage 504 formed by the air guide duct 515.

[0068] As shown in Figure 5B, the internal air drawn in by the circulation fans 501 to 503 flows through the second channels 506a to 506c formed by the air guide ducts 505a to 505c, and into the third channels 507a to 507c where the liquid crystal unit 200 is located. In the third channels 507a to 507c, the internal air absorbs heat from the liquid crystal unit 200 and its temperature rises.

[0069] As shown in Figures 5B and 6, the internal air is discharged upwards from the lighting case 420 and flows into the fourth channel 508 formed by the air guide case 510. When the power fan 512 rotates, the internal air flows out of the fourth channel 508 through the case outlet 510a and passes over the top of the light source block 116. Since the light source block 116 is cooled by a separate path, the temperature rise of the internal air due to the light source block 116 is suppressed.

[0070] As shown in Figure 6, the internal air flowing out from the case outlet 510a flows into a fifth flow path 514 formed by the power supply air duct 513. In the fifth flow path 514, the internal air absorbs heat from the power supply 511 and its temperature rises. Also, viewed from the direction of the internal air flow, the power supply 511 is positioned downstream of the liquid crystal unit 200. With this configuration, the internal air before it is heated comes into contact with the liquid crystal unit 200, which has a low target temperature, thereby improving the cooling effect on the liquid crystal unit 200.

[0071] Subsequently, the internal air, having been heated by absorbing heat from the liquid crystal unit 200 and the power supply 511, flows into the internal air channel 107 through the inlet 108. When combined with the flow of outside air in the outside air channel 105, the internal air is cooled in the first heat exchanger 104 by exchanging heat with the outside air passing through the outside air channel 105 after passing through the internal air channel 107. In other words, heat is transferred from the internal air to the outside air through the partition wall 106. The direction in which the internal air flows in the internal air channel 107 (solid arrow) and the direction in which the outside air flows in the outside air channel 105 (dotted arrow) are opposite. Therefore, heat can be efficiently transferred from the internal air to the outside air.

[0072] Due to heat transfer, the temperature of the internal air at the outlet 112 is lower than the temperature of the internal air at the inlet 108. Therefore, the internal air is returned to the first housing 500 at a lower temperature than when it flowed into the first heat exchanger 104.

[0073] By repeatedly circulating the internal air, the internal air and each component within the first housing 500 can be maintained at a desired temperature without directly taking in outside air.

[0074] Next, we will explain the heat transfer in the second heat exchanger 117.

[0075] As shown in Figure 1, when the outside air fan 114 rotates, outside air flows into the second housing 101 through the intake port 113 and hits the second heat exchanger 117. The outside air that has been heated by hitting the second heat exchanger 117 is discharged outside the second housing 101 through the exhaust port 115. Because the path of outside air to the second heat exchanger 117 is away from the first heat exchanger 104, the laser light source 301, which generates a large amount of heat, can be cooled efficiently, and the cooling of the laser light source 301 can be prevented from affecting the cooling of other components or the internal air. For example, the amount of heat generated by the laser light source 301 is half of the input power.

[0076] The detailed configuration of the optical configuration 100 will be described with reference to Figure 8. Figure 8 is a diagram showing the optical configuration 100 of the projection-type image display device 1 according to Embodiment 1. The optical configuration 100 comprises a light source unit 300 and an illumination optical unit 400.

[0077] [1. Light source configuration] The light source unit 300 includes a laser light source 301, a dichroic mirror 302, excitation lenses 303 and 304, a reflective disc 305, a focusing lens 308, a circular polarizer 309, and a diffuse reflection mirror 310.

[0078] The laser light source 301 has multiple lasers, each emitting blue light and arranged in an array, and a collimating lens in front of each laser.

[0079] The dichroic mirror 302 is positioned at an angle, reflecting only S-polarized light and transmitting only P-polarized light (light that is not S-polarized).

[0080] The excitation lenses 303 and 304 focus the passing light into a point-like shape.

[0081] The reflective disc 305 is coated with a phosphor 306 in an annular shape, and the phosphor 306 fluoresces yellow light when excited by blue light. The reflective disc 305 is rotated by a motor 307. Although the phosphor 306 generates heat locally when irradiated with light, excessive temperature rise is suppressed by the rotation.

[0082] The circular polarizer 309 converts incident light into circularly polarized light.

[0083] The diffuse reflection mirror 310 reflects the incident light, converting it into diffused light.

[0084] Blue light from the laser light source 301 is emitted in the -Y direction and incident on the dichroic mirror 302. Of the blue light, the S-polarized component is reflected in the -X direction. Of the blue light, the P-polarized component is transmitted in the -Y direction.

[0085] The S-polarized light component reflected by the dichroic mirror 302 is incident on the phosphor 306 on the reflective disk 305 by the excitation lenses 303 and 304. Upon impact with the phosphor 306, the incident light becomes yellow light and returns to the dichroic mirror 302 with its ray width expanded by the excitation lenses 303 and 304. Since the yellow light passes through the dichroic mirror 302, the yellow light is incident on the illumination optical unit 400.

[0086] On the other hand, the P-polarized light component that passes through the dichroic mirror 302 is focused onto the diffuse reflection mirror 310 as circularly polarized light by the focusing lens 308 and the circular polarizer 309. The diffuse light reflected from the diffuse reflection mirror 310 has its circular polarization direction reversed and travels in the +Y direction before being incident on the circular polarizer 309 again. Because the circular polarization is incident with the rotation reversed, it becomes S-polarized blue light when it passes through the circular polarizer 309 and is incident on the dichroic mirror 302. Since the S-polarized blue light is reflected by the dichroic mirror 302, the blue light is reflected and incident on the illumination optical unit 400.

[0087] With this configuration, yellow light and blue light are incident on the illumination optical unit 400 from the light source unit 300.

[0088] [2. Configuration of the Illumination Optical Section] The illumination optical unit 400 includes fly-eye lenses 401 and 402, a focusing lens 404, a PBS 405, mirrors 407 to 411, a liquid crystal unit 200, a cross-color prism 414, and a projection lens 421. The illumination optical unit 400 has three liquid crystal units 200 for each color of light (RGB). The illumination optical unit 400 may also be called the projection optical system.

[0089] The fly-eye lenses 401 and 402 have numerous rectangular microlenses of the same shape. Each microlens on the exit-side fly-eye lens 402 corresponds to any microlens on the entry-side fly-eye lens 401. Light passes through the fly-eye lenses 401 and 402, and each microlens on the exit-side fly-eye lens 402 forms a rectangular illumination area forward (+X direction).

[0090] The condensing lens 404 collects the light received from the fly-eye lenses 401 and 402, and a rectangular area image is superimposed to form a uniform illumination area.

[0091] PBS405 is an aggregate of rectangular prisms with a parallelogram cross-section, with a polarizing selective film applied to the slanted surfaces and a strip-shaped phase difference plate 406 bonded to the output surface. The function of PBS405 is not essential to the validity of this disclosure, so here we will only explain that it outputs incident light as colored light with aligned polarization directions. In the configuration of PBS405, appropriate temperature control is necessary because the strip-shaped phase difference plate 406 is made of an organic material.

[0092] Mirrors 407-411 are used to deflect the light received from the focusing lens 404 towards the liquid crystal unit 200. Specifically, mirrors 407 and 409 are dichroic mirrors, while mirrors 408, 410, and 411 are reflective mirrors.

[0093] The liquid crystal unit 200 includes an incident polarizer 201, a liquid crystal panel 202, and an output polarizer 203, all arranged in order from the incident side of each color of light. The rectangular area formed by the fly-eye lenses 401, 402 and the condensing lens 404 is set to cover the image display area of ​​the liquid crystal panel 202.

[0094] The incident polarizer 201 is formed by laminating a polarizer to a base glass. The polarization axis of the polarizer is set to transmit only light in the polarization direction of the light incident within a rectangular area. The polarizer in the incident polarizer 201 generates heat because it absorbs several percent of the light, even when the polarization axis of the transmitted light is aligned.

[0095] The liquid crystal panel 202 is equipped with liquid crystals that can be independently controlled for each of the many pixels. Between the pixels, there are light-shielding masks to prevent malfunction of the driving electrical components. For example, light incident on the liquid crystal panel 202 is transmitted through each liquid crystal pixel by the liquid crystal driving circuit that receives the video signal, either maintaining the polarization direction at the time of incidence or changing the polarization direction, before passing through the liquid crystal panel 202. In the liquid crystal panel 202, light is absorbed by the light-shielding masks or, to a small extent, by the liquid crystals, causing the liquid crystal panel 202 to generate heat.

[0096] The output polarizer 203 is formed by laminating a polarization-selective member (polarizer or wire grid) to a base glass. For example, polarized light not driven by the liquid crystal panel 202 is transmitted with only slight absorption by the polarization-selective member on the output polarizer 203, but polarized light driven by the liquid crystal panel 202 is absorbed and not transmitted depending on the degree of modulation. As a result, the output polarizer 203 generates heat. Since the output polarizer 203 generates more heat than other members, especially when displaying black, the polarization-selective member may be an aluminum wire grid with excellent heat resistance, or multiple polarizers with a low degree of polarization may be used in combination.

[0097] Because the LCD unit 200 generates heat, cooling of the LCD unit 200 is required to maintain the driving performance of the LCD or to suppress deterioration of the polarizing plate.

[0098] The cross-color prism 414 is equipped with a red-reflecting dichroic coating 412 and a blue-reflecting dichroic coating 413. Each color of light is combined by the cross-color prism 414.

[0099] The projection lens 421 is configured to project an enlarged image formed on the liquid crystal panel 202 of the liquid crystal unit 200 onto a screen not shown in the diagram.

[0100] Here, light incident from the light source 300 passes through the incident fly-eye lens 401 and the exit fly-eye lens 402, and the microlenses on the exit fly-eye lens 402 form a rectangular illumination area in front (+X direction). These illumination areas are focused by the condensing lens 404, and the rectangular area images are superimposed to form a uniform illumination area. As described above, the light guided into the rectangular area formed by the fly-eye lenses 401, 402 and the condensing lens 404 is aligned in any polarization direction.

[0101] Light passing through the focusing lens 404 enters the dichroic mirror 407. This dichroic mirror 407 has the characteristic of reflecting only blue light and transmitting other colored light. The blue light reflected by the dichroic mirror 407 is further reflected by the reflective mirror 408 and reaches the blue component of the liquid crystal unit 200. The yellow light that has passed through the dichroic mirror 407 enters the dichroic mirror 409, which has the characteristic of reflecting green light, and only the green light component reaches the green component of the liquid crystal unit 200. The red light remaining as transmitted light after the green component has been removed from the yellow light by the dichroic mirror 409 is reflected by the reflective mirrors 410 and 411 and reaches the red component of the liquid crystal unit 200.

[0102] The light of each color that has passed through the liquid crystal unit 200 is combined in the +Y direction by the cross-color prism 414 and emitted, passing through the dustproof glass 415 and reaching the projection lens 421. When the light is emitted from the projection lens 421, the image displayed by the liquid crystal unit 200 is projected onto the screen in an enlarged size.

[0103] (effect) The projection-type image display device 1 according to this embodiment can achieve the following effects.

[0104] As described above, the projection-type image display device 1 according to this embodiment is a projection-type image display device comprising a laser light source 301 (light source) and a liquid crystal unit 200 (image display element) to which light from the laser light source 301 is incident. The projection-type image display device 1 comprises a first housing 500, a second housing 101, a first heat exchanger 104, a second heat exchanger 117, and an outside air fan 103 (first blower). The first housing 500 houses the laser light source 301 and the liquid crystal unit 200, forming a sealed first space X1. The second housing 101 encloses the first housing 500, forming a second space X2 between itself and the first housing 500, and has an outside air intake port 102 and an outside air exhaust port 111. The first heat exchanger 104 is located in the second space X2 and transfers the heat from the liquid crystal unit 200 to the outside air in the second space X2. The second heat exchanger 117 is located in the second space X2 and transfers the heat from the laser light source 301 to the outside air in the second space X2. The outside air fan 103 is located in the second space X2 and takes in outside air into the second space X2 through the intake port 102 and expels the outside air from the second space X2 through the exhaust port 111.

[0105] This configuration allows the heat-generating laser light source 301 and liquid crystal unit 200 to be cooled in a sealed state. Therefore, dust and water droplets from the outside air can adhere to the laser light source 301 and liquid crystal unit 200, and salt damage can be suppressed. In addition, by transferring the heat from the laser light source 301 and liquid crystal unit 200 to the outside air via different heat exchangers 104 and 117, cooling can be achieved more efficiently.

[0106] In the projection-type image display device 1 according to this embodiment, the first heat exchanger 104 has a partition wall 106 that defines an internal air passage 107 on one side and an external air passage 105 on the other side. The internal air passage 107 has an inlet 108 and an outlet 112 that communicate with the first space X1. The external air passage 105 is in contact with the internal air passage 107 via the partition wall 106 and allows outside air to pass through. The projection-type image display device 1 is further equipped with circulation fans 501 to 503 (second blowers) which are arranged in the first space X1 and guide the internal air in the first space X1 to the internal air passage 107, pass through the internal air passage 107, and guide it to the liquid crystal unit 200. The external air fan 103 guides the outside air in the second space X2 to the external air passage 105, passes through the external air passage 105, and discharges it through the exhaust port 111.

[0107] With this configuration, the first heat exchanger 104 can transfer the heat generated in the liquid crystal unit 200 from the internal air to the outside air. In addition, the cooled internal air can be blown to the liquid crystal unit 200 to cool it.

[0108] The projection-type image display device 1 according to this embodiment further comprises an air guide duct 515 (first duct) and air guide ducts 505a to 505c (second ducts). The air guide duct 515 extends between the outlet 112 of the internal air passage 107 of the first heat exchanger 104 and the circulation fans 501 to 503. The air guide ducts 505a to 505c extend between the circulation fans 501 to 503 and the liquid crystal unit 200.

[0109] This configuration allows the cooled internal air to be more reliably blown to the liquid crystal unit 200.

[0110] The projection-type image display device 1 according to this embodiment further includes a power supply air duct 513 (third duct) extending between the liquid crystal unit 200 and the inlet 108 of the internal air passage 107 of the first heat exchanger 104. The power supply 511 for the laser light source 301 is housed in the power supply air duct 513.

[0111] This configuration allows internal air to be blown to the power supply 511, thereby cooling the power supply 511. Furthermore, by blowing internal air to the liquid crystal unit 200 before blowing it to the power supply 511, a greater cooling effect can be obtained in the liquid crystal unit 200. Therefore, even when the liquid crystal unit 200 has a low target temperature, the heat generated by the liquid crystal unit 200 can be kept below the target temperature.

[0112] The projection-type image display device 1 according to this embodiment further includes a power fan 512 (third blower) that introduces air into the power supply air intake duct 513.

[0113] This configuration allows for more reliable airflow to the power supply 511.

[0114] In the projection-type image display device 1 according to this embodiment, a first flow path 504 is formed by an air guide duct 515. Second flow paths 506a to 506c are formed by air guide ducts 505a to 505c. A fifth flow path 514 (third flow path) is formed by a power supply air guide duct 513. A third flow path 507a to 507c (fourth flow path) is formed, which houses the liquid crystal unit 200 and communicates with the second flow paths 506a to 506c.

[0115] This configuration allows for more reliable airflow to the liquid crystal unit 200.

[0116] In the projection-type image display device 1 according to this embodiment, the second heat exchanger 117 is a heat sink connected to the laser light source 301.

[0117] With this configuration, the heat from the laser light source 301 is transferred to the heat sink in the second space X2 through thermal conduction and dissipated to the outside air.

[0118] In the projection-type image display device 1 according to this embodiment, the second housing 101 has an air intake port 102 (first air intake port) and an air intake port 113 (second air intake port) as air intake ports. The first heat exchanger 104 is positioned closer to the air intake port 102 than to the air intake port 113. The second heat exchanger 117 is positioned closer to the air intake port 113 than to the air intake port 102.

[0119] This configuration allows relatively low-temperature outside air to come into contact with each of the heat exchangers 104 and 117 before heat exchange. In other words, the laser light source 301 and the liquid crystal unit 200 are cooled by different paths of outside air. Therefore, the first heat exchanger 104 can be used to efficiently cool the liquid crystal unit 200, while the first heat exchanger 104 can be used to cool the laser light source 301.

[0120] The projection-type image display device 1 according to this embodiment is further equipped with an outside air fan 114 (fourth blower) which is located in the second space X2 and takes in outside air into the second space X2 through the air intake port 113 and guides it to the second heat exchanger 117.

[0121] This configuration improves the heat dissipation effect in the second heat exchanger 117.

[0122] In the projection-type image display device 1 according to this embodiment, the partition wall 106 has a corrugated shape.

[0123] This configuration increases the contact area between the outside air passage 105 and the inside air passage 107, thereby improving the heat exchange efficiency in the first heat exchanger 104.

[0124] In the projection-type image display device 1 according to this embodiment, the outside air fan 103 is an axial flow fan or sirocco fan that is waterproof or oil-proof.

[0125] This configuration suppresses failure of the outside air fan 103 and allows for high static pressure while saving space.

[0126] In the projection-type image display device 1 according to this embodiment, the first housing 500 and the second housing 101 have a common base 118 as their bottom.

[0127] This configuration simplifies the manufacturing of the housings 500 and 101. It also simplifies the assembly of the projection-type image display device 1 and reduces the overall height of the device.

[0128] In the projection-type image display device 1 according to this embodiment, the first housing 500 is made of resin, and the second housing 101 is made of metal.

[0129] With this configuration, the first housing 500, which is made of a material with thermal insulation properties, becomes less susceptible to thermal influence from the outside air. In addition, by forming it with resin molding, the first housing 500, which has a complex shape, can be easily formed. The second housing 101, which is made of metal, has improved strength and weather resistance compared to the case where it is made of resin.

[0130] In the projection-type image display device 1 according to this embodiment, the first housing includes a liquid crystal unit 200 and houses a projection optical system that projects modulated light.

[0131] This configuration prevents dust and water droplets from the outside air from adhering to the projection optical system and prevents salt damage. Therefore, the projection-type image display device 1 can be used outdoors or in environments where it may be exposed to water.

[0132] In the projection-type image display device 1 according to this embodiment, the direction in which the internal air flows through the internal air passage 107 and the direction in which the external air flows through the external air passage 105 are opposite.

[0133] This configuration improves the heat exchange efficiency in the first heat exchanger 104.

[0134] In Embodiment 1, the sealed space was described as an airtight space where the inflow and outflow of gas to and from the outside is blocked, but it is not limited to this. The sealed space may also be a liquid-tight space where the intrusion of dust and other particles is suppressed and liquids such as water are prevented from entering from the outside.

[0135] In Embodiment 1, an example was described in which there are three circulation fans 501 to 503, but the invention is not limited to this. The number and arrangement of circulation fans may be changed as appropriate depending on the required airflow.

[0136] Although Embodiment 1 described an example with a power supply fan 512, the system is not limited to this. If the necessary airflow can be achieved by the circulation fans 501 to 503 alone, the power supply fan 512 is not necessarily required.

[0137] Although Embodiment 1 described an example with an air guide case 510, the invention is not limited to this. If the space between the lighting case 420 and the electrical circuit board 509 is narrow, the air guide case 510 may actually obstruct the airflow, so it is not always necessary.

[0138] In Embodiment 1, an example was described in which the first heat exchanger 104 has a partition wall 106 and the second heat exchanger 117 is a heat sink, but the invention is not limited to this. The first heat exchanger 104 and the second heat exchanger 117 may have other configurations that allow for heat exchange. The first heat exchanger 104 may be a general heat sink or heat pipe, or a configuration with a partition wall of a different type, as long as it separates the outside air and the inside air and maintains their respective intake and discharge positions.

[0139] In Embodiment 1, an example was described in which the second heat exchanger 117 is mechanically connected to the laser light source 301, but the invention is not limited to this. The second heat exchanger 117 may be connected to the laser light source 301 via a fluid such as a refrigerant. For example, the second heat exchanger 117 has heat transfer tubes that circulate a refrigerant. Heat exchange between the ambient air surrounding the laser light source 301 and the ambient air can be achieved through the circulation of the refrigerant. The ambient air surrounding the laser light source 301 is cooled, thereby cooling the laser light source 301.

[0140] In Embodiment 1, an example was described in which the base 118 of the second housing 101 and the first housing 500 are common, but the invention is not limited to this. The first housing 500 may have a base inside the second housing 101. With this configuration, an air layer is formed between the bases of the second housing 101 and the first housing 500, which can suppress temperature changes of the internal air due to thermal contact from the outside. On the other hand, if the base 118 is common, the projection-type image display device 1 can be made smaller and the number of components can be reduced.

[0141] Furthermore, the circulation fans 501-503 and the outside air fans 103 and 114 may be controlled according to the internal air temperature, outside air temperature, and altitude. With such a configuration, the temperature can be kept to a desired value while minimizing the noise generated. Since the circulation fans 501-503 are located within the first space X1, they may be controlled solely by the temperature monitor inside the first enclosure 500.

[0142] Furthermore, some of the internal air drawn in by the circulation fan 503 may flow into the space surrounding the PBS405. The internal air absorbs heat from the PBS405 and its temperature rises. With this configuration, the PBS405 can be cooled by removing heat.

[0143] In Embodiment 1, a configuration using three transmissive liquid crystal panels in the liquid crystal unit 200 was described, but the invention is not limited to this configuration. Reflective liquid crystal panels may also be used.

[0144] (Embodiment 2) A projection-type image display device 150 according to Embodiment 2 of this disclosure will now be described. In Embodiment 2, the differences from Embodiment 1 will be primarily described. In Embodiment 2, components identical or equivalent to those in Embodiment 1 will be denoted by the same reference numerals. Furthermore, in Embodiment 2, descriptions that overlap with those in Embodiment 1 will be omitted.

[0145] Figure 9 shows the optical configuration 450 of the projection-type image display device 150 according to Embodiment 2. In the figure, the right direction is the +X direction, the upward direction is the +Y direction, and the direction towards the viewer is the +Z direction.

[0146] As shown in Figure 9, the projection-type image display device 150 according to Embodiment 2 differs from the projection-type image display device 1 according to Embodiment 1 in that it uses a DMD (Digital Mirror Device) instead of a liquid crystal unit 200 to perform color display. Unless otherwise stated, the projection-type image display device 150 may have the same structure as the projection-type image display device 1 of Embodiment 1.

[0147] The projection-type image display device 150 has an illumination optical system 451 and a projection optical system 452 including a projection lens 453.

[0148] The illumination optical system 451 has a laser light source 454 as a light source. The laser light source 454 is a semiconductor laser that emits blue light, similar to the laser light source 301 of Embodiment 1, and is emitted forward (+Y direction). The emitted light is incident on the focusing lens 455 and focused. The focused light is incident on the focusing lens 458, which is a concave lens, via the folding mirrors 456 and 457, and is converted into parallel light with a reduced height from the laser light source 454, and is incident on the diffuser plate 459. The diffuser plate 459 increases the uniformity of the light, and it is incident on the dichroic mirror 460.

[0149] The dichroic mirror 460 has the property of transmitting blue wavelength light and reflecting visible light of other wavelengths. Therefore, as in Embodiment 1, the light transmitted through the diffuser plate 459 is blue light and is transmitted and focused by the excitation lenses 461 and 462. The focused light forms a focused spot on the phosphor coated on the phosphor wheel 464 of the phosphor unit 463.

[0150] The phosphor wheel 464 is rotatably fixed to the motor 465 and comprises a region with yellow phosphor on its circumference where a focused spot is formed, and a fan-shaped aperture in a portion of the same circumference. When the phosphor receives strong excitation light, approximately half of the energy received is converted into heat. Above a certain temperature, the phosphor's conversion efficiency decreases due to its thermal quenching characteristics, and its reliability decreases due to the high heat generation.

[0151] The fluorescent light generated by the yellow phosphor in the phosphor wheel 464 returns to the dichroic mirror 460 as diffused light via the excitation lenses 461 and 462. The dichroic mirror 460 reflects the incident yellow fluorescence. When the yellow fluorescence enters the focusing lens 468, it enters the color filter section of the color wheel unit 469. The color wheel unit 469 can rotate the color filter section at high speed using the motor 470. The color filter section has a red transmission filter 471 that selectively transmits only red wavelength light, a green transmission filter 472 that selectively transmits only green wavelength light, and a transparent glass 473 that has been treated with an anti-reflective coating. The red transmission filter 471, the green transmission filter 472, and the transparent glass 473 are each formed in a fan shape and are fixed to the motor hub so that the three components form a disc shape. Furthermore, the timing of the excitation light irradiating the yellow phosphor is synchronized so that the light incident on the red transmission filter 471 and the green transmission filter 472 coincides with the timing of the light incident on the yellow phosphor. The red transmission filter 471 and the green transmission filter 472 remove light other than the wavelength required for the incident fluorescence, thereby achieving the desired color purity.

[0152] The light that has passed through the color filter section reaches the incident surface of the rod integrator 474, undergoes repeated total internal reflection, and then passes through the projection relay lenses 475 and 476 and the field lens 477 before reaching the TIR prism unit 478 of the projection optical system 452.

[0153] The TIR prism unit 478 is formed by bonding the incident prism 479 and the exit prism 480 with an air gap of several microns in between. Light entering the incident prism 479 from the field lens 477 is totally reflected at the air gap surface 481 and exits the incident prism 479, where it enters the DMD 482, which is a light modulation element.

[0154] The DMD482 is a device consisting of multiple micromirrors arranged in a matrix with two selectable tilt angles relative to the base substrate. The tilt angle of the micromirrors is changed based on an external video signal. For example, the micromirrors selectively tilt between a first tilt angle at which their reflected light enters the projection lens 453, and a second tilt angle at which the light emitted from the incident prism 479 has a larger incident angle, and the reflected light is reflected to a position where it does not enter the projection lens 453. Furthermore, as described above, the DMD482 achieves high-speed mirror switching operation in accordance with the video signal corresponding to the colored light that is incident over time.

[0155] On the other hand, light incident on the aperture of the phosphor wheel 464 of the phosphor unit 463 is transmitted without being affected by the phosphor unit 463. The transmitted blue light passes through a blue light relay optical path composed of relay lenses 483, 484, 485, 486 and mirrors 487, 488, 489, and is diffused by the diffuser plate 490. Subsequently, the blue wavelength light passes through a dichroic mirror 460 that reflects only yellow light, following the same optical path as the other colored lights, and passes through the transparent glass 473 of the color filter section of the color wheel unit 469. The timing of transmission through the aperture 467 of the wheel substrate, the timing of transmission through the transparent glass 473 of the color filter section, and the timing of the DMD 482 being driven by the blue video signal are synchronized. Subsequently, after passing through the same optical path as the red and green lights, and being modulated by the DMD 482, a color image can be obtained on a screen (not shown in the figure) by the projection lens 453.

[0156] Figure 10 is a top cross-sectional view of the projection-type image display device 150 according to Embodiment 2. Figure 11 is a top cross-sectional view taken from Figure 10 with the cross-sectional position changed vertically. Figure 12 is a cross-sectional view of the intake section of the projection-type image display device 150 according to Embodiment 2. Figure 13 is a bottom cross-sectional view of the projection-type image display device 150 according to Embodiment 2.

[0157] As shown in Figures 10 and 11, the projection-type image display device 150 includes the optical configuration 450 described above, a first housing 550, a second housing 151, a first heat exchanger 154, an intake fan 153, a DMD heat sink 556, a circulation fan 551, a power supply unit 560, and a light source heat sink 566.

[0158] The first housing 550 and the second housing 151 have the same configuration as in Embodiment 1, with the first housing 550 forming a sealed first space X1, and a second space X2 communicating with the outside being formed between the first housing 550 and the second housing 151.

[0159] As shown in Figure 11, the second housing 151 has an air intake port 152 and an exhaust port 159. An exhaust duct 158 ​​is connected to the exhaust port 159.

[0160] As shown in Figures 11 and 12, the first heat exchanger 154 has an outside air duct, fins, an inside air duct, and a first heat pipe 156. The outside air duct is connected to an intake fan 153 and an exhaust duct 158, forming an outside air passage 155 through which outside air flows. The fins are arranged in the outside air passage 155 and extend along the direction of outside air flow. Multiple fins are provided, each arranged parallel to the others. The fins are made of, for example, aluminum. The inside air duct forms an inside air passage 157 through which inside air flows. The inside air passage 157 communicates with the first space X1. The inside air passage 157 is provided with multiple fins, similar to the outside air passage 155. The first heat pipe 156 is a typical heat pipe that removes heat from the high-temperature side as heat of vaporization by adding a small amount of water to a vacuumed sealed tube, vaporizing it on the high-temperature side, and liquefying it on the low-temperature side. The first heat pipe 156 is positioned to penetrate multiple fins in the internal air passage 157 and multiple fins in the external air passage 155. With this configuration, the internal air passing through the internal air passage 157 can exchange heat with the external air through the fins without directly mixing with the external air.

[0161] The intake fan 153 draws outside air into the second housing 151 through the intake port 152 and blows it to the first heat exchanger 154. The outside air that has passed through the first heat exchanger 154 is discharged to the outside via the exhaust duct 158 ​​and the exhaust port 159 of the second housing 151. The intake fan 153 may be a component already supplied to the market as a waterproof fan or an oil-proof fan.

[0162] The DMD heatsink 556 is connected to the back of the DMD482 via a thermal conductive material (such as grease). By drawing heat from the back, the reliability of the DMD482 can be ensured.

[0163] The circulation fan 551 is a fan positioned in the first space X1 that circulates the internal air between the first heat exchanger 154 and the sealed first space X1. A sirocco fan is used as the circulation fan 551 to obtain high static pressure in a limited space.

[0164] The power supply unit 560 includes a configuration similar to that of the power supply 511 in the first embodiment.

[0165] As shown in Figure 10, the light source heatsink 566 is connected to the light source unit case 565, which houses the laser light source 454, phosphor unit 463, color wheel unit 469, and surrounding optical components of the illumination optical system 451. The light source heatsink 566 is positioned near the power supply fan 558. The light source heatsink 566 enhances the heat dissipation of the light source unit case 565.

[0166] The light source heat sink 566 has a heat receiving section 567, which is not shown in the figure. The heat receiving section 567 is connected to the back of the laser light source 454 (Figure 9), which generates a large amount of heat, via a thermal conductive material. One end of a heat pipe 568 is embedded in the heat receiving section 567. The other end of the heat pipe 568 is connected to a heat dissipation fin 569, and a light source cooling fan 570 is provided adjacent to the heat dissipation fin 569. Therefore, the heat from the laser light source 454 is transferred from the heat receiving section 567 through the heat pipe 568 to the heat dissipation fin 569. In other words, the heat receiving section 567, the heat pipe 568, and the heat dissipation fin 569 together form a heat exchanger. The light source cooling fan 570 may be a component already supplied to the market as a waterproof fan or an oil-proof fan.

[0167] A vent 161 is formed on the intake side of the light source cooling fan 570. The vent 161 is formed in the second housing 151 and communicates with an intake port 162 (Figure 13) which consists of multiple openings. As a result, the heat dissipation fins 569 can flow in from the intake port 162 and efficiently dissipate heat using outside air which is relatively cooler than the inside air. The heated outside air is exhausted from an exhaust port 163 (Figure 11) formed in the second housing 151.

[0168] This configuration allows the heat from a light source with a large heat output to be processed separately from the first heat exchanger 154. This is particularly effective when the light source can absorb heat by being directly connected, such as a laser light source. In this case, since the light source can be cooled directly, it is possible to reduce the space required for the heat exchange configuration. Specifically, compared to configurations using conventional light sources such as discharge lamps, which require heat exchange between air (gas) to lower the ambient temperature, it is possible to reduce the space required for the heat exchange configuration.

[0169] Next, we will explain the circulation of internal air in the first space X1.

[0170] As shown in Figure 13, the interior air is guided from the first heat exchanger 154 to the first flow path 553 formed in the first air intake duct 552 by the circulation fan 551. The first flow path 553 is a sealed flow path between the first heat exchanger 154 and the circulation fan 551.

[0171] The internal air guided by the circulation fan 551 reaches a second flow path 555 formed by a second air guide duct 554 connected to the discharge port of the circulation fan 551. The second flow path 555 is a sealed flow path between the circulation fan 551 and the DMD482.

[0172] As shown in Figure 11, the DMD heatsink 556 is housed in a third channel 557 that communicates with the second channel 555. The second air guide duct 554 (Figure 13) has an opening at the connection point to the third channel 557, and the connection point may have a nozzle shape. With this configuration, air is concentrated on the DMD heatsink 556. The internal air removes heat from the DMD heatsink 556.

[0173] The air that passes through the third airflow channel 557 goes through the power supply fan 558, is formed by the third air guide duct 559, and reaches the fourth airflow channel 561 where the power supply unit 560 is housed. The internal air absorbs heat from the power supply unit 560 and its temperature rises.

[0174] As shown in Figure 13, the third air intake duct 559 forms a partition opening 564 at least on the side of the power supply fan 558 and the side of the fourth duct 562. The partition opening 564 is connected to the fifth flow path 563, and the fifth flow path 563 is connected to the internal air flow path 157 (Figure 12). As a result, the heated internal air reaches the internal air flow path 157 of the first heat exchanger 154.

[0175] As the internal air flows around the multiple fins in the internal air channel 157, heat exchange occurs with the external air channel 155, and heat is removed from the internal air. As a result, the temperature of the internal air decreases, and the internal air, at a relatively low temperature, circulates again through the channel leading to the first air channel 553.

[0176] As stated above, it is clear that this disclosure is also valid in configurations using DMDs as image display elements. Similar effects can be expected with LEDs, which are solid-state light sources.

[0177] Although Embodiment 2 described a configuration using one DMD, it is not limited to this. Any number of DMDs may be used.

[0178] In Embodiment 2, an example was described in which the first heat exchanger 154 uses a heat pipe, but the embodiment is not limited to this. The first heat exchanger 154 may have other configurations, such as a configuration using corrugated sheets. Conversely, it goes without saying that a heat exchanger consisting of a heat pipe and fins can be used in Embodiment 1.

[0179] In Embodiment 2, an example was described in which cooling air is concentrated on the DMD heatsink 556 on the back of the DMD482, but the invention is not limited to this. The internal air from the circulation fan 551 may be branched to cool the projection optical system or the DMD482. Alternatively, a dedicated circulation fan may be added separately.

[0180] Although Embodiment 2 describes an example with a power supply fan 558, the invention is not limited to this. The power supply fan 558 may be omitted if sufficient airflow to the light source heatsink 566 can be ensured to suppress the temperature rise of the light source unit case 565.

[0181] The projection image display device in the first embodiment is a projection image display device comprising a light source and an image display element into which light from the light source is incident, comprising: a first housing that houses the light source and the image display element and forms a sealed first space; a second housing that encloses the first housing and forms a second space with the first housing, and has an outside air intake port and an outside air exhaust port; a first heat exchanger disposed in the second space that transfers heat from the image display element to the outside air in the second space; a second heat exchanger disposed in the second space that transfers heat from the light source to the outside air in the second space; and a first blower disposed in the second space that takes in outside air into the second space through the intake port and discharges outside air from the second space through the exhaust port.

[0182] As a projection-type image display device in a second embodiment, in the projection-type image display device in the first embodiment, the first heat exchanger has a partition wall that defines an internal air passage on one side and an external air passage on the other side, the internal air passage has an inlet and an outlet that communicate with a first space, the external air passage is in contact with the internal air passage via the partition wall and allows external air to pass through, and further comprises a second blower which is located in the first space and guides the internal air in the first space into the internal air passage, passes through the internal air passage, and guides it to an image display element, the first blower guides the external air in the second space into the external air passage, passes through the external air passage, and discharges it through an exhaust port.

[0183] As a projection-type image display device in a third embodiment, the projection-type image display device in the second embodiment further comprises a first duct extending between the outlet of the internal air passage of the first heat exchanger and the second blower, and a second duct extending between the second blower and the image display element.

[0184] In the fourth embodiment, the projection-type image display device is further comprising a third duct extending between the image display element and the inlet of the internal airflow channel of the first heat exchanger, the third duct housing the power supply for the light source.

[0185] In the fifth embodiment, the projection-type image display device is further provided with a third blower for introducing air into the third duct, as in the projection-type image display device of the fourth embodiment.

[0186] As a projection-type image display device in the sixth embodiment, in the projection-type image display device in the fourth or fifth embodiment, a first flow path is formed by a first duct, a second flow path is formed by a second duct, a third flow path is formed by a third duct, an image display element is housed, and a fourth flow path is formed that communicates with the second flow path.

[0187] As a projection-type image display device in the seventh embodiment, in the projection-type image display device in the fourth or fifth embodiment, a third heat exchanger is connected to the image display element, a first flow path is formed by a first duct, a second flow path is formed by a second duct, a third flow path is formed by a third duct, a third heat exchanger is housed, and a fourth flow path is formed that communicates with the second flow path.

[0188] In the eighth embodiment, as a projection-type image display device, in any of the first to seventh embodiments, the second heat exchanger is a heat sink connected to a light source.

[0189] As a projection-type image display device in the ninth embodiment, in a projection-type image display device in any of the first to eight embodiments, the second housing has a first air intake and a second air intake as air intakes, the first heat exchanger is positioned closer to the first air intake than the second air intake, and the second heat exchanger is positioned closer to the second air intake than the first air intake.

[0190] As a projection-type image display device in the tenth embodiment, the projection-type image display device in the ninth embodiment further comprises a fourth blower arranged in a second space, which takes in outside air into the second space through a second air intake and guides it to a second heat exchanger.

[0191] In the eleventh embodiment, as a projection-type image display device, in any of the second to seventh embodiments, the partition wall has a corrugated shape.

[0192] In the twelfth embodiment, as a projection-type image display device, in any of the first to eleven embodiments, the first blower is a waterproof or oil-proof axial flow fan or sirocco fan.

[0193] In the 13th embodiment, as a projection-type image display device, in any of the 1 to 12 embodiments, the first housing and the second housing have a common base as their bottom.

[0194] As a projection-type image display device in the 14th embodiment, in a projection-type image display device in any of the 1 to 13 embodiments, the first housing is made of resin and the second housing is made of metal.

[0195] As a projection-type image display device in the 15th embodiment, in a projection-type image display device in any of the 1 to 14 embodiments, the first housing includes an image display element and houses a projection optical system that projects modulated light.

[0196] In the projection-type image display device of the 16th embodiment, in the projection-type image display device of any of the 2nd to 7th embodiments or the 11th embodiment, the direction in which the internal air flows in the internal air channel and the direction in which the external air flows in the external air channel are opposite.

[0197] While this disclosure is adequately described in relation to preferred embodiments with reference to the accompanying drawings, various variations and modifications will be obvious to those skilled in the art. Such variations and modifications should be understood to be included within the scope of this disclosure as defined by the attached claims. [Industrial applicability]

[0198] This disclosure is applicable to projection-type image display devices and projection-type video display devices having heat-generating components. [Explanation of symbols]

[0199] 1. Projection-type image display device 100 optical configurations 101 Second cabinet 102 Intake port 103 Outdoor fan 104 1st heat exchanger 105 Outside air flow path 106 Bulkhead 107 Internal air flow path 108 Inlet 111 Exhaust vent 112 Outlet 113 Air intake 114 Outdoor fan 115 Exhaust port 116 Light source blocks 117 Second heat exchanger 118 base 500 First cabinet 501 Circulating Fan 502 Circulation Fan 503 Circulation Fan 504 First channel 505a~505c Air duct 506a~506c Second channel 507a~507c Third channel 508 Fourth channel 509 Electrical circuit board 511 Power supply 510 Air duct case 512 Power Supply Fan 513 Power supply air duct 515 Air duct X1 1st space X2 2nd space

Claims

1. A projection-type image display device comprising a light source and an image display element into which light from the light source is incident, A first housing that houses the light source and the image display element and forms a sealed first space, A second housing encloses the first housing, forming a second space between it and the first housing, and having an air intake port for outside air and an air exhaust port for outside air, A first heat exchanger is placed in the second space and transfers the heat of the image display element to the outside air in the second space, A second heat exchanger is placed in the second space and transfers the heat of the light source to the outside air in the second space, A projection-type image display device comprising: a first blower positioned in the second space, which takes in outside air into the second space through the intake port and discharges the outside air from the second space through the exhaust port.

2. The first heat exchanger has a partition wall that defines an internal airflow path on one side and an external airflow path on the other side, The internal air passage has an inlet and an outlet that communicate with the first space, The aforementioned outside air passage is in contact with the aforementioned inside air passage via the partition wall and allows outside air to pass through. The system further comprises a second blower, which is positioned in the first space and guides the internal air in the first space into the internal air passage, passes it through the internal air passage, and guides it to the image display element. The projection-type image display device according to claim 1, wherein the first blower guides outside air from the second space into the outside air passage, causes it to pass through the outside air passage, and discharges it through the exhaust port.

3. A first duct extending between the outlet of the internal air passage of the first heat exchanger and the second blower, The projection-type image display device according to claim 2, further comprising a second duct extending between the second blower and the image display element.

4. The third duct further comprises the image display element and the inlet of the internal air passage of the first heat exchanger, The projection-type image display device according to claim 3, wherein the power supply for the light source is housed in the third duct.

5. The projection-type image display device according to claim 4, further comprising a third blower for introducing air into the third duct.

6. The first duct forms the first flow path, The second duct forms a second flow path, The third duct forms a third flow path, The projection-type image display device according to claim 4, wherein the image display element is housed and a fourth channel is formed that communicates with the second channel.

7. A third heat exchanger is connected to the aforementioned image display element. The first duct forms the first flow path, The second duct forms a second flow path, The third duct forms a third flow path, The projection-type image display device according to claim 4, wherein the third heat exchanger is housed and a fourth flow path is formed that communicates with the second flow path.

8. The projection-type image display device according to claim 1, wherein the second heat exchanger is a heat sink connected to the light source.

9. The second housing has a first intake port and a second intake port as the air intake ports, The first heat exchanger is positioned closer to the first air intake than the second air intake. The projection-type image display device according to claim 1, wherein the second heat exchanger is positioned closer to the second air intake than the first air intake.

10. The projection-type image display device according to claim 9, further comprising a fourth blower arranged in the second space, which takes in outside air into the second space through the second air intake and guides it to the second heat exchanger.

11. The projection-type image display device according to claim 2, wherein the partition wall has a corrugated shape.

12. The projection-type image display device according to claim 1, wherein the first blower is a waterproof or oil-proof axial fan or sirocco fan.

13. The projection-type image display device according to claim 1, wherein the first housing and the second housing have a common base as their bottom.

14. The first housing is made of resin, The projection-type image display device according to claim 1, wherein the second housing is made of metal.

15. The projection-type image display device according to any one of claims 1 to 14, wherein the first housing includes the image display element and houses a projection optical system for projecting modulated light.

16. The projection-type image display device according to claim 2, wherein the direction in which the internal air flows in the internal air passage is opposite to the direction in which the external air flows in the external air passage.

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